WO2005117561A2

WO2005117561A2 - Compositions and methods for diagnosing and treating diseases using low density lipoprotein-like lipid emulsions

Info

Publication number: WO2005117561A2
Application number: PCT/US2005/019698
Authority: WO
Inventors: Pedro M. Tosetti; Eric G. Kirschner; Raul C. MARANHÃO
Original assignee: Icell Therapeutics; Laherty, Carol, D.
Priority date: 2004-06-04
Filing date: 2005-06-03
Publication date: 2005-12-15
Also published as: BRPI0511739A; WO2005117561A3

Abstract

The present invention relates to low density lipoprotein-like emulsions that bind to low density lipid receptors, and therapeutic uses of such emulsions. The invention further relates to the use of low density lipoprotein-like emulsions in the diagnosis and treatment of a variety of diseases and disorders, including cardiovascular and ocular diseases.

Description

COMPOSITIONS AND METHODS FOR DIAGNOSING AND TREATING DISEASES USING LOW DENSITY LIPOPROTEIN-LIKE LIPID EMULSIONS

BACKGROUND OF THE INVENTION

Field of the Invention The present invention relates to low density lipoprotein-like lipid emulsions and their use in the delivery of therapeutic agents and the diagnosis, treatment and prevention of disease.

Description of the Related Art A major challenge facing the pharmaceutical industry lies in providing therapeutic agents to specifically targeted tissues or cells at a sufficient dosage to provide a therapeutic benefit, without prohibitively harming the patient being treated. Accordingly, it is an important goal of the pharmaceutical industry to develop drug delivery vehicles and methods that target diseased tissues and cells. A variety of different general approaches have been taken, with various degrees of success. These include, e.g., implanting drug delivery devices, attaching cell- or tissue-specific targeting moieties to therapeutic compounds, and encapsulating therapeutic compounds in liposomes. In addition, lipid emulsions having a chemical composition similar to low density lipoproteins (LDLs) have been used for the targeted delivery of chemotherapeutic agents to neoplastic cells, which overexpress LDL receptors bound by the lipid emulsions (described in U.S. Patent No. 5,578,583). However, such emulsions have not previously been used to target cells or tissues associated with other major diseases, such as cardiovascular and ocular diseases. Cardiovascular disease is the number one cause of death in the industrialized world. According to the World Health Organization, more than 12 million people suffer each year from heart attacks and strokes. Coronary artery disease, the primary form of cardiovascular disease (CVD), is the major cause of death in the United States today, responsible for over 550,000 deaths per year. Cerebrovascular disease is the third leading cause of death in the United States. The etiology of both coronary artery and cerebrovascular diseases is attributed to atherosclerosis. Through its clinical manifestations, atherosclerosis is the major cause of the more than one million heart attacks and approximately 400,000 strokes that occur each year. In addition to the high morbidity and mortality associated with atherosclerosis, it has been estimated that atherosclerosis has cost the United States' economy over $80 billion each year in lost wages, lost productivity, and medical care costs (Levy, R., Am. Heart J. 110: 1116 (1985)). A substantial body of evidence has established a relationship between hypercholesterolemia and premature atherosclerosis; the higher the levels of plasma cholesterol, the greaterthe risk of subsequent heart attack (Steinberg, D., JAMA 264: 3047 (1991 ); Lipid Research Clinics Program, JAMA 251 : 351 (1984); Rifkind, B., Am. J. Cardiol. 54: 30C (1984)). Atherosclerosis is a complex disease that is associated with a variety of etiologic factors. Studies have shown that, of the major factors involved, diet- induced hyperlipidemia and genetic defects or abnormalities in lipoprotein metabolism have received the most attention. The local disease process of atherosclerosis is characterized by the accumulation of lipids in the walls of blood vessels. Concomitant with lipid accumulation, there is vascular cell damage resulting in dysfunction of the endothelium, smooth muscle proliferation, and matrix deposition. These changes ultimately result in the formation of what is termed "plaque." As these plaques expand and mature, ruptures in their surface can occur, leading to major thrombotic events. This process, which can occur in essentially all of the blood vessels of the body, results in many of the major disease categories of our time, including coronary artery disease, peripheral vascular disease, myocardial infarction and stroke. Vascular smooth muscle cells play an important role during vascular development and in vascular diseases, such as atherosclerosis, that are characterized by alterations in the control of smooth muscle growth and/or differentiation. Abnormal blood vessel growth is found in a variety of diseases including cancer, arthritis, psoriasis, and in eye diseases (i.e., ocular diseases). Examples of such ocular neovasculature diseases include, but are not limited to, macular degeneration; neoplasias, e.g., retinoblastoma; diabetic retinopathy; open angle glaucoma; and various infections and trauma, e.g., to the cornea. The most well known forms of ocular diseases associated with neovascular formation are macular degeneration and diabetic retinopathy, constituting the leading cause of blindness in the United States. In the United States alone, 15 million people are diagnosed with macular degeneration. Macular degeneration can be subdivided into dry and wet types with 13.5 million and 1.5 million cases respectively. There are 2 million new cases of macular degeneration per year. There are 16 million people in the United States with Type 1 and Type 2 diabetes, and within 15 years, 80% of Type 1 patients have developed diabetic retinopathy, while 84% of Type 2 diabetic patients develop retinopathy within 19 years. Although it is not completely understood how either macular degeneration or diabetic retinopathy occur in the eye, it is understood that the vessels are formed through a combination of hypoxia, inflammation and oxidative products similar to some of the conditions found inside developing solid tumors. For this reason, it is believed that anti-angiogenesis drugs, including those proven effective at treating solid tumors, may be used as therapeutic agents for the treatment of ocular diseases. It has been demonstrated that the growth of a highly aggressive intraocular tumor in mice could be inhibited significantly by treating the mice with eye drops containing the angiostatic agent anecortave acetate. Neovascular glaucoma is a form of glaucoma that most commonly is associated with proliferative diabetic retinopathy (PDR) and central retinal vein occlusion (CRVO). Other causative factors include carotid occlusive disease (carotid artery plaques resulting in significant lumen narrowing or occlusion), central retinal artery occlusion (CRAO), temporal arteritis, and other conditions that result in ischemia of the retina or ciliary body. The primary mechanism of neovascular glaucoma is neovascularization in the angle of the eye causing obstruction to fluid egress via the trabecular meshwork. When the retina is ischemic, it is believed that an angiogenic factor is released from the ischemic tissue, resulting in the development of neovascularization, primarily in the optic nerve, retina, iris, and angle of the eye. Medical management of ocular neovascular diseases is difficult and includes a variety of drug and surgical treatments, including glaucoma filtration surgery, implantation of a glaucoma drainage device (tube shunt), or cyclocryotherapy (freezing therapy of the ciliary body, which produces aqueous fluid). Laser cyclophotocoagulation, which entails use of a laser to destroy part of the ciliary body, may also be used. Laser ablation of the vessels in the angle of the eye is only occasionally effective and may be used as a temporary measure to help keep the angle open. Most pharmacologic management of ocular disease uses the topical application of solutions to the surface of the eye as drops. Factors that can limit the usefulness of topical drug application include the significant barrier to solute flux provided by the corneal epithelium and the rapid and extensive precomeal loss that occurs as the result of drainage and tear fluid turnover. It has been estimated that typically less than 5% of a topically applied drug permeates the cornea and reaches intraocular tissues. The major portion of the instilled dose is absorbed systemically by way of the conjunctiva, through the highly vascular conjunctival stroma and through the lid margin vessels. Recent advances in topical drug delivery have been made that improve ocular drug contact time and drug delivery, including the development of ointments, gels, liposome formulations, and various sustained and controlled- release substrates, such as the Ocusert, collagen shields, and hydrogel lenses. The development of newer topical delivery systems using polymeric gels, colloidal systems, and cyclodextrins may also prove effective. However, the delivery of therapeutic doses of drugs to the appropriate cells and tissues of the eye remains a significant challenge. Clearly, there remains a need in the art for effectively targeting drug delivery to cells associated with specific diseases and disorders, including diseases associated with smooth muscle cell proliferation and neovascularization. The present invention meets this need by providing compositions and methods that may be used to deliver therapeutic agents to diseased cells. In addition, the invention also provides related compositions and methods that may be used for the diagnosis, treatment, and prevention of a variety of diseases, including cardiovascular and ocular diseases.

BRIEF SUMMARY OF THE INVENTION The present invention is drawn to low density lipoprotein-like lipid emulsions (LDEs) and uses thereof. The invention, therefore, includes LDEs, compositions comprising LDEs, and related methods of manufacturing and using LDEs. In one embodiment, the LDE is a protein-free emulsion. In certain embodiments, the LDEs of the present invention further comprise one or more apolipoproteins or mimemtics thereof. In one embodiment, the invention provides a composition adapted for cardiovascular delivery, comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises a therapeutic agent, and wherein said therapeutic agent is used in the treatment of a cardiovascular disease or disorder. In a related embodiment, the invention includes a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises a therapeutic agent, wherein said LDE binds a low density lipoprotein receptor (LDLR), and wherein overexpression of said LDLR is associated with a cardiovascular disease or disorder. In a specific embodiment, the LDLR is LR11. In various embodiments, the LDE comprises a hydrophobic core surrounded by a monolayer of phospholipids, and it may also comprise free cholesterol and/or a surfactant on the surface of said monolayer of phospholipids. In particular embodiments, the hydrophobic core consists essentially of cholesterol esters, triglycerides, or mixtures thereof. The invention further includes compositions and methods wherein the LDE is detectably labeled. In one embodiment, the LDE is labeled with a radioactive label. In a particular embodiment, the label is [¹⁴C]cholesterol oleate, [³H]cholesterol oleate, [³H]triolein, [³H]cholesterol, ^99mTc, ²³l, ³¹l, ³²P, ¹⁹²lr¹⁰³Pd, ¹⁹⁸Au ¹¹¹ln, ⁶⁷Ga, ²⁰¹TI, ¹⁵³Sm, ¹⁸F or ⁹⁰Sr. In other embodiments, the LDE is fluorescently labeled. In various related embodiments, compositions of the invention include any of a variety of therapeutic agents. In one embodiment, the therapeutic agent is hydrophobic. In related embodiments, the therapeutic agent is an antianginal agent, antiarrhythmic agent, antihypertensive agent, antithrombotic and fibrinolytic agent, blood lipid-lowering agent, congestive heart failure drug, anti-inflammatory agent, inflammatory agent, growth factor, isotope, fluorescently labeled compound, cell growth inhibitor, or cell growth stimulator. Specific embodiments of antianginal agents include organonitrates, calcium channel blockers, and beta-ad renergic antagonists. Specific embodiments of antiarrhythmic agents include sodium channel blockers, beta-adrenergic blockers, repolarization drugs, calcium channel blockers, adenosine, and digoxin. Specific embodiments of antihypertensive agents include alpha adrenergic antagonists, beta-adrenergic antagonists, combined alpha/beta-adrenergic antagonists, adrenergic neuron blocking agents, CNS-acting antihypertensives, anti-angiotensin II agents, calcium channel blockers, diuretics, and direct vasodilators. Specific embodiments of antithrombotic and fibrinolytic agents include anticoagulants, anticoagulant antagonists, antiplatelet agents, thrombolytic agents, and thrombolytic agent antagonists. Specific embodiments of blood lipid-lowering agents include resins, HMG CoA reductase inhibitors, fibric acid derivatives, nicotinic acid and probucol. Specific embodiments of congestive heart failure drugs include inotropic agents, angiotensin antagonists, diuretics, combined afterload-preload reduction drugs, and beta-adrenergic blockers. Specific embodiments of anti-inflammatory agents include steroid anti-inflammatory agents, including bethametasone, cortisone, hydrocortisone, dexametasone, methylprednisolone, prednisolone, prednisone, and triacinolone, and non-steroid anti-inflammatory agents, including salicylates, p- aminophenols, iondoles, heteroaryl acetic acids, arylpropionic acids, and enolic acids. In various embodiments of the invention, the therapeutic agent is paclitaxel or an analog or derivative thereof. In a specific embodiment, the therapeutic agent is a lipophilic prodrug of paclitaxel, such as, e.g., paclitaxel oleate. In particular related embodiments, the therapeutic agent is a peptide or polypeptide, an oligonucleotide, a radiopharmaceutical compound, a fluorescently labeled compound, or single radioactive seeds. In yet another embodiment, compositions of the invention include a polypeptide. In one embodiment, the polypeptide is an apolipoprotein, which may be apolipoprotein E. In another embodiment, compositions of the invention include a pharmaceutically acceptable excipient. Other embodiments of the invention include compositions comprising a solid support, wherein said lipid emulsion is associated with the solid support. In one embodiment, the solid support is an implantable medical device, such as, e.g., a balloon, stent, coil, or tissue engineering scaffold. In another related embodiment, compositions of the invention include at least one additional therapeutic agent, wherein said additional therapeutic agent is used in the treatment of a cardiovascular disease or disorder. Certain embodiments of the invention include an implantable medical device, wherein said device comprises a solid support and a low density lipoprotein-like lipid emulsion (LDE). In a particular embodiment, the solid support is coated with said LDE. In another embodiment, the LDE comprises a therapeutic agent. In one embodiment, the therapeutic agent is used in the treatment of a cardiovascular disease or disorder. In a related embodiment, the solid support is a balloon, stent, coil, or tissue engineering scaffold. In another embodiment, the LDE further comprises at least one additional therapeutic agent. The invention further contemplates a method of delivering a cardiovascular therapeutic agent to a patient, comprising introducing to the patient a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises the cardiovascular therapeutic agent. In a particular embodiment, the LDE binds a low density lipoprotein receptor (LDLR) and said cardiovascular therapeutic agent is selectively delivered to cells expressing the LDLR. In one embodiment, said LDLR is LR11. In certain embodiments, the cardiovascular therapeutic agent is any of those described above. In particular embodiments, the patient has been diagnosed with or is suspected of having a cardiovascular disease. In related embodiments, the cardiovascular disease is restenosis, atherosclerosis, coronary heart disease, lipidemia, or peripheral vascular disease, such as an aneurism. The invention also provides a method for determining the presence or absence of a cardiovascular disease, comprising delivering a composition comprising a labeled low density lipoprotein-like lipid emulsion (LDE) to a subject, detecting an amount of labeled LDE bound to the subject's vasculature, and comparing the amount of bound LDE to either a predetermined cut-off value or a control amount detected in a subject known to not have cardiovascular disease, wherein an increase in the amount as compared to the predetermined cut-off value or control amount is indicative of the presence of cardiovascular disease. In another embodiment, the invention includes a method of staging a cardiovascular disease, comprising delivering a composition comprising a labeled low density lipoprotein-like lipid emulsion (LDE) to a subject, detecting an amount of labeled LDE bound to the subject's vasculature, and comparing the amount of bound LDE detected in step (b) to one or more predetermined values, each associated with a cardiovascular disease stage, thereby determining the stage of cardiovascular disease. In one embodiment, the LDE binds LR11. In various embodiments of methods of the invention, the LDE is delivered to the subject's bloodstream. In other embodiments, the LDE is associated with a solid support, and the LDE is delivered by implanting the solid support into the subject. In another embodiment, the invention includes a method of delivering a cardiovascular therapeutic agent to an atherosclerotic lesion, comprising introducing a solid support to the site of the atherosclerotic lesion in a subject, wherein a low density lipoprotein-like lipid emulsion (LDE) comprising the cardiovascular therapeutic agent is associated with the solid support. In a particular embodiment, the LDE binds a low density lipid receptor overexpressed in the atherosclerotic lesion. In another embodiment, the solid support is an implantable medical device. In various embodiments, the cardiovascular therapeutic agent is any of those described above. The invention further includes a related embodiment of a method of capturing apolipoprotein E present in a subject's plasma, comprising delivering a low density lipoprotein-like lipid emulsion (LDE) to the subject's bloodstream, wherein said LDE binds apolipoprotein E. In addition, the invention includes the related embodiment of a method of removing a polypeptide from a lipoprotein present in a subject's plasma, comprising delivering a low density lipoprotein-like lipid emulsion (LDE) to the subject's bloodstream, wherein said LDE competes with lipoproteins, chylomicrons and other protein-binding lipids for binding the polypeptide. In a specific embodiment, the polypeptide is apolipoprotein E. In various embodiments of methods of the invention, the LDE comprises a hydrophobic core surrounded by a monolayer of phospholipids. In yet another related embodiment, the invention includes a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises a vascular smooth muscle cell (VSMC) growth factor, or a fragment, variant, or inhibitor thereof, and wherein said LDE binds an LDL-receptor related protein (LRP). In one embodiment, the growth factor is connective tissue growth factor (CTGF). In a related embodiment, the LDE binds a VSMC. In a related embodiment, the invention includes a method of stimulating vascular smooth muscle cell growth and/or migration, comprising delivering a composition comprising a low density lipoprotein-like lipid emulsion (LDE) to a subject, wherein said LDE comprises a vascular smooth muscle cell (VSMC) growth factor, or a fragment or variant thereof, and wherein said LDE binds an LDL-receptor related protein (LRP). The invention further includes a method of inhibiting vascular smooth muscle cell growth and/or migration, comprising delivering a composition comprising a low density lipoprotein-like lipid emulsion (LDE) to a subject, wherein said LDE comprises an inhibitor of a vascular smooth muscle cell (VSMC) growth factor, and wherein said LDE binds an LDL-receptor related protein (LRP). In various embodiments of methods of the invention, the VSMC growth factor is connective tissue growth factor. A further embodiment of the invention provides a method of treating a patient diagnosed with or suspected of having a peripheral vascular disease, comprising delivering to said patient a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises a vascular smooth muscle cell (VSMC) growth factor, or a fragment or variant thereof, and wherein said LDE binds an LDL-receptor related protein (LRP). In one embodiment, the disease is an aneurism. In another embodiment, the LDE is associated with an implantable medical device. A further embodiment of the invention includes a method of treating a patient diagnosed with or suspected of having restenosis or atherosclerosis, comprising delivering to said patient a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises an inhibitor of a vascular smooth muscle cell (VSMC) proliferation, wherein said LDE binds an LDL-receptor related protein (LRP). In particular embodiments, the inhibitor is an inhibitor of a VSMV growth factor. In a specific embodiment, the LDE is associated with an implantable medical device. In specific embodiments of these methods, the VSMC growth factor is connective tissue growth factor. The invention also provides a related method of treating a patient having a cardiovascular disease or disorder, comprising delivering to said patient a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE promotes cholesterol efflux from macrophages. In yet another embodiment, the invention includes a process for producing a low density lipoprotein-like lipid emulsion (LDE) comprising a therapeutic agent, wherein said therapeutic agent is used in the treatment of a cardiovascular disease or disorder, comprising preparing an LDE and combining said LDE with said therapeutic agent. In one embodiment, combining is performed by sonication, ultrasound treatment, and/or homogenization. In a related embodiment, the invention includes a process for producing a low density lipoprotein-like lipid emulsion (LDE) comprising a therapeutic agent, comprising preparing an LDE and homogenizing said LDE in the presence of said therapeutic agent. In a further related embodiment, the invention includes a method of treating a patient diagnosed with or suspected of having a disease associated with neovascularization, comprising: delivering to said patient a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises an inhibitor of blood vessel growth, and wherein said LDE binds an LDL-receptor related protein (LRP). In particular embodiments, the disease associated with neovascularization disease is arthritis, psoriasis or an ocular disease. In particular embodiments, the ocular disease is macular degeneration, diabetic retinopathy or glaucoma. According to various embodiments of the invention, compositions are provided topically or systemically. In addition, compositions may be associated with an implantable medical device. In one embodiment, an inhibitor of blood vessel growth is an inhibitor of angiogenesis. In certain embodiments, an inhibitor of blood vessel growth or angiogenesis targets an angiogenic factor selected from the group consisting of: angiopoietin-1, basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF). In particular embodiments, an inhibitor is a statin, e.g., angiostatin or endostatin.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) Figures 1 A and 1 B are graphical depictions of the reduction in intima thickness and area observed in rabbits treated with LDE-paclitaxel oleate (LDE:PO) as compared to controls. Figure 1 A depicts intima thickness; Figure 1 B depicts intima area. Figure 2A and 2B are graphical depictions of the dose-dependent increase in vascular smooth muscle cell proliferation observed upon treatment with TGF-β1 (Figure 2A) or GM-CSF (Figure 2B). Figures 3A and 3B are graphical depictions of the amount of TGF-β1 released upon vascular smooth muscle cell injury as compared to a control. Figures 3A and 3B represent the results of two independent experiments. Figure 4 is a graphical depiction of the decrease in wound area observed upon treatment with TGF-β1 as compared to a control. Figure 5 illustrates western blot analysis of collagen III (top) and fibronectin (bottom) protein expression by vascular smooth muscle cells treated with various amounts of TGF-β1 and/or GM-CSF. Figure 6 is a graphical depiction of the amount of paclitaxel oleate associated with LDE at various time points when dialyzed against plasma (open circle) or Tris-HCI buffer (filled circle). Results are presented as means + SEM (bars) of three experiments. Figures 7A and 7B are graphical depictions of the effect of cell survival of serial dilutions of a Cremophor/EL stock solution of paclitaxel, paclitaxel oleate, or LDE-paclitaxel oleate. Figure 7A shows the dose-response curves of the cytostatic activity of paclitaxel oleate (filled circle) and of paclitaxel (open circle), both using Cremophor/EL as solubilizing agent. Figure 7B shows the dose- response curve of the cytostatic activity of LDE-paclitaxel oleate with (open circle) or without (filled circle) Cremophor EL/ethanol and of commercial paclitaxel (filled square). Results are presented as means + SEM (bars) of three experiments performed in triplicate. Figure 8A is a graphical depiction of uptake by cultivated cells of increasing amounts of LDE-paclitaxel oleate doubly labeled with [¹⁴C]-cholesteryl ester (filled circle) and [³H]-paclitaxel oleate (open circle). Figure 8B graphically illustrates the effect of addition of increasing amounts of human LDL (50-400 μg/ml) on the uptake by cells of LDE-paclitaxel oleate doubly labeled with [¹⁴C]- cholesterol ester (filled square) and [³H]-paclitaxel oleate (open circle). The concentration of LDE-paclitaxel oleate was constant corresponding to 200 μg/ml. Cells were incubated for 4 hours at 37 °C. Results are presented as means + SEM (bars) of three experiments performed in triplicate.

DETAILED DESCRIPTION OF THE INVENTION This invention provides novel compositions and related methods of diagnosing, treating and preventing diseases, including diseases associated with neovascularization and/or smooth muscle cell proliferation, e.g., cardiovascular and ocular diseases, in a subject in need thereof. The invention is based, in large part, upon the surprising discovery that low density lipoprotein-like lipid emulsions can be used to specifically deliver a therapeutic compound to tissues and/or cells associated with particular diseases, including cardiovascular disease, peripheral vascular disease, and ocular diseases. In certain embodiments, the compositions of the invention are used in targeting vascular smooth muscle cells, and are, therefore, particularly useful in treating and preventing diseases and disorders associated with deregulated smooth muscle proliferation, including those associated with angiogenesis.

A. Low density lipoprotein-like lipid emulsions and compositions thereof The present invention includes low density lipoprotein-like lipid emulsions (LDEs) comprising one or more therapeutic agents. In certain embodiments, the LDEs are labeled with a detectable label to facilitate their detection. Such LDEs may be used alone or in combination with an active agent, e.g., a therapeutic compound, according to various aspects of the invention.

1. Low density lipoprotein-like lipid emulsions (LDEs) Lipid emulsions of the present invention, generally referred to as low density lipoprotein-like lipid emulsions (LDEs) are protein-free microemulsions having a lipid composition resembling that of low density lipoprotein (LDL). LDEs, including their composition and method of preparation, are described in detail in

Redgrave, T.G. and Maranhao, R.C, Biochim. Biophys. Acta 835:104-112 (1985); Maranhao, R.C. et ai, Biochim. Biophys. Acta 875:247-255 (1986); Redgrave,

T.G. et ai, Lipids 23:101-105 (1988); Ginsburg, G.S. et ah, J. Biol. Chem.

257:8216-8227 (1982); Maranhao, R.C. etal., Brazilian J. Med. Biol. Res. 25:1003-

1007 (1992); Maranhao, R.C. etal., Lipids 28:691 -696 (1993); Maranhao, R.C. et ai, Cancer Research 54:4660-4666 (1994); and Hirata, R.D.C. et al., Biochim. Biophys. Acta 1437:53-62 (1999). LDEs generally bind one or more protein components of the lipoproteins, including, e.g., apolipoprotein A-l, apolipoprotein A-l I, apolipoprotein

B, apolipoprotein C-l, apoliprotein Cll, apolipoprotein C-lll, apolipoprotein D, apolipoprotein E, apolipoprotein E2, apolipoprotein E3, and/or apolipoprotein E4. In particular embodiments of the invention, compositions comprising LDE further comprise a protein component, such as, e.g., apolipoprotein B-100 or apolipoprotein E, or a fragment thereof. When bound to a protein component, LDEs are capable of binding to one or more low density lipoprotein family receptors and related molecules. For example, LDE binds to the LDL receptor, as well as to other receptors such as LRP, LR11 , etc. LDEs without apolipoprotein have a markedly different metabolic behavior, emphasizing the importance of the protein component for its capacity to bind the LDL receptor (Maranhao, R.C. etal., Lipids 28:691-696 (1993)). The LDL receptor (LDLR) is a prototype for a large family of cell surface receptors implicated in biological processes ranging from lipoprotein uptake to Wnt signal transduction. These proteins combine several types of structural units in similar arrangements, such that groups of cysteine-rich LDL-A modules precede regions with clusters of epidermal growth factor-like (EGF) modules and b-propeller domains containing conserved YWTD motifs. Each receptor then terminates with a transmembrane segment and a cytoplasmic tail of variable length. A variety of receptors related to the LDL receptor have been identified, including the very low density lipoprotein receptor (VLDLR) and ApoER2. A second class of LDL receptor related proteins that contain LDL-A, EGF-like, and YWTD domains in a different arrangement include LRP-5 and LRP-6. The LDE may bind specifically to one or more particular LDL receptors or LDL receptor related proteins. Binding is considered specific when it occurs with an at least two-fold, five-fold or ten-fold higher affinity as compared to binding to a control polypeptide. LDEs may bind to free protein components within plasma, or, alternatively, they may compete with endogenous LDLs for binding to protein components and may, therefore, capture protein components, including apoE, from endogenous LDLs, such as, e.g., very low density lipoproteins (VLDLs). In one embodiment, the LDE binds to LR11. LR11 , a mosaic LDL receptor family member, is highly expressed in vascular smooth muscle cells (SMCs) of the hyperplastic intima. LR11 is also highly expressed in the atheromatous plaque areas of apoE knockout mice, particularly in the intimal SMCs at the border between intima and media. Zhu, Y. etal., Circ Res.94(6):752- 8. Epub (2004). In addition, LR11 expression is markedly increased in atherosclerotic lesions. Kanaki, T. et al., Arterioscler. Thromb. Vase. Biol. (November 1999):2687-2695. LR11 has also been demonstrated to mediate the uptake of ApoE-rich lipoproteins in vitro. Taira, K. et al., Arterioscler. Thromb. Vase. Biol. (Sept. 2001 ):1501 -1506. In another embodiment, the LDE binds LRP1/A2MR, another LDL receptor-related protein, which is implicated in coronary atherosclerosis. Schulz, S. et al., Hum. Mutat. 20:404 (2002). In certain embodiments, the LDE is oxidized. Oxidized LDL is a major inflammatory stimulant. Oxidized low-density lipoproteins also play a critical role in the development and progression of atherosclerosis. It is generally believed that oxidized lipoproteins are formed by free radical damage to lipids that accumulate in macrophages and smooth muscle cells causing foam cell formation, an initial step in disease. Accordingly, oxidized LDE may be used as an inflammatory agent, e.g., to provoke the formation of scar tissue. LDEs are emulsions and, as such, are typically composed of particles that are substantially spherical and formed of a hydrophobic lipid core surrounded by a lipid and/or surfactant layers. In particular embodiments, the hydrophobic core is surrounded by a single lipid and/or surfactant layer. Any of a number of lipids and surfactants may be present in LDEs of the present invention, including amphipathic, neutral, cationic, and anionic lipids and surfactants. Examples of neutral lipids that can be included, i.e., lipid species that exist either in an uncharged or neutral zwitterionic form at physiological pH, include but are not limited to mono-, di- and triacylglycerols, sterols such as cholesterol, fatty acid cholesterol esters, tocopherols, and complex glycerolipids and sphingolipids such as mono- and diacylphosphatidylcholines, etherlipids, phosphatidylethanolamines, ceramides, sphingomyelins, cephalins, cerebrosides and polymer-derivatized lipids such as poly(ethylene glycol) modified lipids. Examples of cationic lipids include, but are not limited to, N,N-dioleyl-N,N- dimethylammonium chloride ("DODAC"); N-(2,3-dioleyloxy)propyl-N,N-N- triethylammonium chloride ("DOTMA"); N,N-distearyl-N,N-dimethylammonium bromide ("DDAB"); N-(2,3-dioleoyloxy)propyl)-N,N,N-trimethylammonium chloride (^,,DOTAP"); 3β-(N-(N^,,N'-dimethylaminoethane)-carbamoyl)cholesterol ("DC-Chol"), N-(1-(2,3-dioleyloxy)propyl)-N-2-(sperminecarboxamido)ethyl)-N,N- dimethylammonium trifluoracetate ("DOSPA"), dioctadecylamidoglycyl carboxyspermine ("DOGS"), 1 ,2-dileoyl-sn-3-phosphoethanolamine ("DOPE"), 1 ,2- dioleoyl-3-dimethylammonium propane ("DODAP"), and N-(1,2-dimyristyloxyprop- 3-yl)-N,N-dimethyl-N-hydroxyethyl ammonium bromide ("DMRIE"). Anionic lipids suitable for use in the present invention include, but are not limited to, phosphatidylglycerols, phosphatidylserines, diacylphosphatidic acids, cardiolipin, N-dodecanoyl phosphatidylethanoloamine, N-succinyl phosphatidylethanolamine, N-glutaryl phosphatidylethanolamine, lysylphosphatidylglycerol, and other anionic modifying groups joined to neutral lipids. In one embodiment, the hydrophobic core consists essentially of or consists of cholesterol esters, triglycerides, or mixtures thereof. In particular embodiments, the hydrophobic core consists essentially of or consists of cholesterol esters or triglycerides. In one particular embodiment, LDE is comprised of phospholipids and triacylglycerols with the phospholipid component constituting 10-70% (by weight) of the total LDE components and the triacylglycerolsl 0-90% (by weight).of the total LDE components In one particular embodiment, LDE is comprised of phospholipids and cholesterol esters with the phospholipid component constituting 10-70% (by weight) of the total LDE components and the cholesterol esters constituting10-90% (by weight). In another particular embodiment, the LDE has a chemical composition of approximately 64% animal or plant-derived or synthetic phosphatidylcholine, 33% cholesteryl oleate, 1 % cholesterol and 2% triolein (by weight). In certain embodiments, LDEs of the invention include cholesterol, while in other embodiments LDEs of the invention do not include cholesterol. a. Detectable labels In certain embodiments, the LDE is detectably labeled. The invention contemplates the use of any type of detectable label, including, e.g., visually detectable labels, fluorophores, and radioactive labels. The detectable label may be incorporated at any site within the LDE, including, e.g., within or attached, either covalently or non-covalently, to any lipid or cholesterol constituent of the LDE. A wide variety of radioactive isotopes may be used to label LDE, including, e.g., ¹⁴C, ³H, ^99mTc, ¹²³l, ¹³¹l, ³²P, ¹⁹²lr¹⁰³Pd, ¹⁹⁸Au, ^{1 1}ln, ⁶⁷Ga, ²⁰¹TI, ¹⁵³Sm, ¹⁸F and ⁹⁰Sr. Examples of specific radioactive labeled compounds that may be used to label the LDE include, but are not limited to: [¹⁴C]cholesterol oleate, [³H]cholesterol oleate, [³H]triolein, and [³H]cholesterol. b. Compositions comprising an LDE and a therapeutic agent The invention further includes novel compositions, e.g., pharmaceutical compositions, comprising an LDE and one or more therapeutic agents. Accordingly, in one embodiment, a composition comprises an LDE and a therapeutic agent, while in another embodiment, a composition comprises an LDE and two or more therapeutic agents. The therapeutic agents may be used in the treatment of the same or different diseases. In addition, in certain embodiments, a first therapeutic agent is used in the treatment of a disease or disorder, while an additional therapeutic agent is used to treat, reduce, or ameliorate a side-effect resulting from treatment with the first therapeutic agent (or even a different treatment or therapy). Therapeutic agents may be present in any region of the LDE. For example, a therapeutic agent may be located in the hydrophobic nucleus, the phospholipid layer, or associated with the surface of an LDE. Accordingly, in certain embodiments, a therapeutic agent is hydrophobic, while in other embodiments, a therapeutic agent may be hydrophilic (e.g., when associated with the surface of an LDE). The compounds and compositions of the invention may further comprise one or more buffers (e.g., neutral buffered saline or phosphate buffered saline), carbohydrates (e.g., glucose, mannose, sucrose or dextrans), mannitol, proteins, polypeptides or amino acids such as glycine, antioxidants, bacteriostats, chelating agents such as EDTA or glutathione, adjuvants (e.g., aluminum hydroxide), solutes that render the formulation isotonic, hypotonic or weakly hypertonic with the blood of a recipient, suspending agents, thickening agents and/or preservatives. In one embodiment, the compositions are formulated for topical application to the eye. Typically, the compositions will contain at least about 0.1% of the active compound or more, although the percentage of the active agent may, of course, be varied and may conveniently be between about 1 or 2% and about 60% or 70% or more of the weight or volume of the total composition. Naturally, the amount of active compound(s) in each therapeutically useful composition may be prepared in such a way that a suitable dosage will be obtained in any given unit dose of the compound. Factors such as solubility, bioavailability, biological half- life, route of administration, product shelf life, as well as other pharmacological considerations will be contemplated by one skilled in the art of preparing such pharmaceutical formulations, and as such, a variety of dosages and treatment regimens may be desirable. The compounds and compositions described herein may be presented in unit-dose or multi-dose containers, such as sealed ampoules or vials, and kits comprising the same and, optionally, instructions for use. Such containers are typically sealed in such a way to preserve the sterility and stability of the compositions until use. In general, compositions may be stored as suspensions, solutions or emulsions in oily or aqueous vehicles. Alternatively, a pharmaceutical composition may be stored in a freeze-dried condition requiring only the addition of a sterile liquid carrier immediately prior to use. The development of suitable dosing and treatment regimens for using the particular compositions described herein in a variety of diagnostic and treatment regimens, including, e.g., oral, intraocular, parenteral, intravenous, intranasal, and intramuscular administration and formulation, as well as those associated with an implanted medical device, will depend, in large part, upon the therapeutic agent being administered, the disease being treated, and characteristics of the subject being treated. Such dosing and treatment regimens can be readily determined by those of skill in the art. c. Therapeutic agents The invention includes compositions comprising any therapeutic agent or active compounds. In certain embodiments, therapeutic agents are used to treat any of a variety of different diseases and disorders, including, but not limited to, bacterial infections and mycoses, viral infections, parasitic diseases, neoplasms (cancers), musculoskeletal diseases, digestive system diseases, stomatognathic diseases, respiratory and pulmonary diseases, otorhinolaryngolic diseases, nervous system diseases, ocular diseases, urologic and make genital diseases, female genital diseases and pregnancy complications, cardiovascular diseases, hemic and lymphatic diseases, congenital, hereditary and neonatal diseases and abnormalities, skin and connective tissue diseases, nutritional and metabolic diseases, endocrine diseases, immunologic diseases, disorders of environmental origin, poisoning, animal diseases, other pathological conditions, signs and symptoms, and mental disorders. In certain embodiments, a therapeutic agent is an agent that promotes or induces cell growth. In particular embodiments, a therapeutic agent is a vascular smooth muscle cell (VSMC) growth factor, which, as used herein, means any agent that induces or is capable of inducing growth or proliferation of a vascular smooth muscle cell. One example is connective tissue growth factor. I In other embodiments, a therapeutic agent is an agent that inhibits or reduces cell growth, such as vascular smooth muscle cell growth. In particular embodiments, a therapeutic agent is an inhibitor of a vascular smooth muscle cell growth factor. In certain embodiments, therapeutic agents used according to the invention are drugs used to prevent or treat cardiovascular or peripheral vascular diseases or disorders. Examples of such drugs include, but are not limited to, antianginal agents, antiarrhythmic agents, antihypertensive agents, antithrombotic and fibrinolytic agents, blood lipid-lowering agents, congestive heart failure drugs, anti-inflammatory agents, inflammatory agents, growth factors, isotopes, cell growth inhibitors, and cell growth stimulators. Exemplary antianginal agents include organonitrates, calcium channel blockers, and beta-adrenergic antagonists. Exemplary antiarrhythmic agents include sodium channel blockers, beta-adrenergic blockers, repolarization drugs, calcium channel blockers, adenosine, and digoxin. Exemplary antihypertensive agents include alphar adrenergic antagonists, beta-adrenergic antagonists, combined alpha/beta- adrenergic antagonists, adrenergic neuron blocking agents, CNS-acting antihypertensives, anti-angiotensin II agents, calcium channel blockers, diuretics, and direct vasodilators. Exemplary antithrombotic and fibrinolytic agents include anticoagulants, anticoagulant antagonists, antiplatelet agents, thrombolytic agents, and thrombolytic agent antagonists. Exemplary blood lipid-lowering agents include resins, HMG CoA reductase inhibitors, fibric acid derivatives, nicotinic acid and probucol. Exemplary congestive heart failure drugs include inotropic agents, angiotensin antagonists, diuretics, combined afterioad-preload reduction drugs, and beta-adrenergic blockers. Exemplary anti-inflammatory agents include steroid anti-inflammatory agents, including bethametasone, cortisone, hydrocortisone, dexametasone, methylprednisolone, prednisolone, prednisone, and triacinolone, and non-steroid anti-inflammatory agents, including salicylates, p-aminophenols, iondoles, heteroaryl acetic acids, arylpropionic acids, and enolic acids. In certain embodiments, therapeutic agents are anti-angiogenic agents. In certain embodiments, therapeutic agents reduce, inhibit, prevent or block neovascularization or reduce, inhibit, prevent or block smooth muscle cell growth or differentiation. In recent years, researchers have discovered that some chemotherapy drugs already in use, e.g., paclitaxel (Taxol), doxorubicin (Adriamycin), epirubicin, mitoxantrone, and cyclophosphamide, among others, have some antiangiogenic effects. Accordingly, therapeutic agents include any of such chemotherapy drugs. Additional examples of preferred therapeutic agents include transforming growth factors (TGF), including TGF-β1 , and granulocyte/macrophage colony stimulating factor (GM-CSF). In one embodiment, a therapeutic agent is paclitaxel or an analog or derivative thereof. Paclitaxel is a highly derivatized diterpenoid (Wani etal., J. Am. Chem. Soc. 93:2325, 1971), which has been obtained from the harvested and dried bark of Taxus brevifolia (Pacific Yew.) and Taxomyces Andreanae and Endophytic Fungus of the Pacific Yew (Stierle etal., Science 60:214-216, 1993). Generally, paclitaxel acts to stabilize microtubular structures by binding tubulin to form abnormal mitotic spindles. "Paclitaxel" (which should be understood herein to include analogs and derivatives such as, for example, TAXOL. RTM., TAXOTERE.RTM., 10-desacetyl analogs of paclitaxel, and 3'N-desbenzoyl-3'N-t- butoxy carbonyl analogues of paclitaxel) may be readily prepared utilizing techniques known to those skilled in the art (see also WO 94/07882, WO 94/07881 , WO 94/07880, WO 94/07876, WO 93/23555, WO 93/10076, U.S. Pat. Nos. 5,294,637, 5,283,253, 5,279,949, 5,274,137, 5,202,448, 5,200,534, 5,229,529, and EP 590267), or obtained from a variety of commercial sources, including for example, Sigma Chemical Co., St. Louis, Mo. (T7402-from Taxus brevifolia). Representative examples of paclitaxel derivatives or analogs include 7-deoxy-docetaxol, 7,8-cyclopropataxanes, N-substituted 2-azetidones, 6,7-epoxy paclitaxels, 6,7-modified paclitaxels, 10-desacetoxytaxol, 10-deacetyltaxol (from 10-deacetylbaccatin III), phosphonooxy and carbonate derivatives of taxol, taxol 2', 7-di(sodium 1 ,2-benzenedicarboxylate, 10-desacetoxy- 11 ,12-dihydrotaxol- 10,12(18)-diene derivatives, 10-desacetoxytaxol, Protaxol (2'-and/or 7-O-ester derivatives ), (2'-and/or 7-O-carbonate derivatives), asymmetric synthesis of taxol side chain, fluoro taxols, 9-deoxotaxane, (13-acetyl-9-deoxobaccatine III, 9- deoxotaxol, 7-deoxy-9-deoxotal, 10-desacetoxy-7-deoxy-9-deoxotaxol, Derivatives containing hydrogen or acetyl group and a hydroxy and tert-butoxycarbonylamino, sulfonated 2'-acryloyltaxol and sulfonated 2'-O-acyl acid taxol derivatives, succinyltaxol, 2'-.gamma.-aminobutyryltaxol formate, 2'-acetyl taxol, 7-acetyl taxol, 7-glycine carbamate taxol, 2'-OH-7-PEG(5000) carbamate taxol, 2'-benzoyl and 2',7-dibenzoyl taxol derivatives, other prodrugs (2'-acetyltaxol; 2',7-diacetyltaxol; 2'succinyltaxol; 2'-(beta-alanyl)-taxol); 2'gamma-aminobutyryltaxol formate; ethylene glycol derivatives of 2'-succinyltaxol; 2'-glutaryltaxol; 2'-(N,N- dimethylglycyl) taxol; 2'-(2-(N,N-dimethylamino)propionyl)taxol;

2'orthocarboxybenzoyl taxol; 2'aliphatic carboxylic acid derivatives of taxol, Prodrugs {2'(N,N-diethylaminopropionyl)taxol, 2'(N,N-dimethyglycyl)taxol, 7(N,N- dimethylglycyl)taxol, 2',7-di-(N,N-dimethylglycyl)taxol, 7(N,N- diethylaminopropionyl)taxol, 2',7-di(N,N-diethylaminopropionyl)taxol, 2'-(L- glycyl)taxol, 7-(L-glycyl)taxol, 2',7-di(L-glycyl)taxol, 2'-(L-alanyl)taxol, 7-(L- alanyl)taxol, 2',7-di(L-alanyl)taxol, 2'-(L-leucyl)taxol, 7-(L-leucyl)taxol, 2',7-di(L- leucyl)taxol, 2'-(L-isoleucyl)taxol, 7-(L-isoleucyl)taxol, 2',7-di(L-isoleucyl)taxol, 2'-(L- valyl)taxol, 7-(L-valyl)taxol, 2'7-di(L-valyl)taxol, 2'-(L-phenylalanyl)taxol, 7-(L- phenylalany)taxol, 2',7-di(L-phenylalanyl)taxol, 2'-(L-prolyl)taxol, 7-(L-prolyl)taxol, 2',7-di(L-prolyl)taxol, 2'-(L-lysyl)taxol, 7-(L-lysyl)taxol, 2',7-di(L-lysyl)taxol, 2'-(L- glutamyl) taxol, 7-(L-glutamyl)taxol, 2',7-di(L-glutamyl)taxol, 2'-(L-arginyl)taxol, 7- (L-arginyl)taxol, 2',7-di(L-arginyl)taxol}, Taxol analogs with modified phenylisoserine side chains, taxotere, (N-debenzoyl-N-tert-(butoxycaronyl)- 10- deacetyltaxol, and taxanes (e.g., baccatin III, cephalomannine, 10- deacetylbaccatin III, brevifoliol, yunantaxusin and taxusin). In certain embodiments, paclitaxel derivatives, such as hydrophic taxane derivatives or prodrugs, including those described, e.g., in U.S. Patent No. 6,291 ,690, are used in accordance with the present invention. In one particular embodiment, the therapeutic agent is paclitaxel oleate, which is described in Lundberg, B.B. et al., J. Controlled Release 86:93-1000 (2003). In additional embodiments, therapeutic agents are drugs used to prevent or treat an ocular disease or disorder. The role of vascular endothelial growth factor (VEGF) in neovascularization, including, e.g., pathological ocular neovascularization, is well characterized. VEGF has been shown to be capable of inducing choroidal neovascularization (CNV), which is the wet form of macular degeneration. Therefore, in certain embodiments, the present invention includes anti-VEGF drugs, which block EGF expression and/or activity. In one particular embodiment, the therapeutic agent is an anti-VEGF antibody, e.g., RhuFab™ (Genentech; S. San Francisco, CA), which binds to VEGF, thus blocking its ability to induce new blood vessel growth and subsequently leakage beneath the retina, which leads to wet AMD vision loss. In another particular embodiment, the therapeutic agent is an anti-VEGF aptamer, e.g., pegaptanib sodium (Macugen™; Eyetech Pharmaceuticals; New York, NY). In further embodiments, therapeutic agents are statins. Researchers studying the use of statins have demonstrated that patients with age-related macular degeneration (AMD) who took statins were only half as liable to develop the more serious form of AMD, the wet form, than those who were not taking them. In one embodiment, the therapeutic agent is angiostatin. Angiostatin is a polypeptide of approximately 200 amino acids. It is produced by the cleavage of plasminogen, a plasma protein that is important for dissolving blood clots. Angiostatin binds to subunits of ATP synthase exposed at the surface of the cell embedded in the plasma membrane. In another embodiment, the therapeutic agent is endostatin. Endostatin is a polypeptide of 184 amino acids. It is the globular domain found at the C-terminus of Type XVIII (18) collagen (a collagen found in blood vessels), released from the parent molecule. Ischemic injuries also cause ocular damage and lead to, e.g., glaucoma, retinal ischemic disease, retinal degeneration, and optic neuropathy. Many ischemic ocular diseases are treated initially by removing the source of the insult, but the ischemic damage remains. Recently, it has been shown that brain- derived neurotrophic factor (BDNF), a member of the neurotrophins, has a protective effect on retinal injury induced by KCN treatment, which causes energy depletion and mimics ischemia. Thus, BDNF may provide new strategies for treating retinal ischemic diseases as a neuroprotectant. Accordingly, in one embodiment, a therapeutic agent is BDNF or a functional fragment or derivative thereof. Therapeutic agents include any class of molecule, including, e.g., peptides and polypeptides; antibodies or fragments or derivatives thereof; nucleic acids, including, e.g., single-stranded or double-stranded DNA or RNA molecules or hybrids thereof, antisense RNA or DNA sequences, RNA interference molecules; ribozymes; organic molecules, including small organic compounds; and inorganic molecules. In addition, therapeutic agents include radiopharmaceutical compounds and radioactive seeds, including single radioactive seeds. Incorporation of a given agent to LDE or the stability of the incorporation may be effected or facilitated by modifications or alterations, including, but not limited to, chemical modifications, e.g., addition of fatty acids, esterification, etc. d. Medical devices The invention further includes compositions comprising an LDE and, optionally, one or more therapeutic agents (e.g., paclitaxel oleate), wherein said composition is associated with a solid support. Accordingly, in one embodiment, the invention includes a medical device, preferably an implantable medical device, comprising an LDE. In certain embodiments, the solid support has features commonly associated with being "biocompatible," in that it is in a form that does not produce an adverse, allergic or other untoward reaction when administered to a mammalian host. Solid supports may be formed from either natural or synthetic materials, or both. The supports may be non-biodegradable, e.g., in instances where it is desirable to leave permanent structures in the body; or biodegradable, e.g., wherein treatment with the therapeutic agent is required only for a short duration of time. In preferred embodiments, solid supports are implantable devices and may, therefore, take the form of balloons, stents (including drug-eluting stents), coils, tissue engineering scaffolds sponges, implants, contact lenses, tubes, or nanoparticles. Medical devices also include prosthetics. Sometimes referred to as a "coated" or "medicated" stent, a drug-eluting stent is a typically metal stent that has been coated with a polymer or other material and a pharmacologic agent (drug) that is known to interfere with the process of restenosis (reblocking). Other examples of implantable medical devices include replacement heart valves and implanted cerebella stimulators. In particular embodiments, the solid support has appropriate structure to restore or maintain blood flow through an occluded blood vessel. In certain embodiments, compositions of the invention are associated with drug delivery devices, including, e.g., solid supports. Such drug delivery devices may be used to regulate the delivery of the composition of the invention to a patient, either locally or systemically. In one embodiment, a composition of the invention is provided to a patient using an ocular implant. Accordingly, in certain embodiments, a composition of the invention is associated with an ocular implant. The choice of solid support material will vary according to the particular circumstance and the site of implantation or treatment. Physical and chemical characteristics, such as, e.g., biocompatibility, biodegradability, strength, rigidity, interface properties and even cosmetic appearance may be considered in choosing a solid support, as is well known to those of skill in the art. Where the solid supports are to be maintained at a site of implantation for extended periods of time, non-biodegradable supports may be employed, such as sintered hydroxyapatite, bioglass, aluminates, other bioceramic materials and metal materials, including titanium. Polymeric matrices may also be employed, including acrylic ester polymers and lactic acid polymers, as disclosed in U.S. Patent Nos. 4,521 ,909, and 4,563,489, respectively. Particular examples of useful polymers are those of orthoesters, anhydrides, propylene-cofumarates, or a polymer of one or more γ-hydroxy carboxylic acid monomers, e.g., γ-hydroxy auric acid (glycolic acid) and/or γ-hydroxy propionic acid (lactic acid). The compositions of the invention may be associated with solid supports that protect them from rapid elimination from the body. Such solid supports include controlled release formulations, including, but not limited to, implants and microencapsulated delivery systems, and biodegradable, biocompatible polymers, such as ethylene vinyl acetate, polyanhydrides, polyglycolic acid, polyorthoesters, polylactic acid and others. A compound or composition of the invention may be associated with the surface of a solid support, or, alternatively, it may be located within a solid support, including, for example, a biodegradable support. Similarly, a compound or composition of the invention may be enclosed within or entrapped within a solid support or component thereof, such as, for example, a microsphere. e. Combination therapies Compounds and compositions of the present invention may be used alone or in combination with one or more additional therapeutic agents or treatments. Accordingly, a compound or composition of the invention may be administered to a subject before, during or after treatment with one or more additional therapeutic agents or treatments. This additional treatment may include any type of treatment, including the administration of a therapeutic agent, i.e., drug, surgical treatment, radiation therapy, or the implantation of a medical device or physical support. In certain embodiments, a composition of the invention comprises two or more therapeutic agents. Generally, the two or more therapeutic agents are used in combination therapy for a particular disease. However, an additional therapeutic agent may be used to reduce or alleviate a side-effect associated with treatment from the first therapeutic agent or even a different agent or therapy. Compositions of the present invention may, therefore, comprise one, two, or more therapeutic agents. A variety of combination therapies are known in the art for treating cardiovascular, ocular, and other diseases, and any such combination may be used according to the present invention. In certain embodiments, a composition of the present invention may be administered in combination with a different type of therapy, such as, e.g., surgery or angioplasty. In other embodiments, a composition of the present invention may be administered in combination with another therapeutic agent, which may be administered independently of or as an additional component of the composition of the invention. A variety of combination therapies for the treatment of cardiovascular diseases have been described, and these and other combination therapies are contemplated by the invention. For example, patients with increased global coronary heart disease (CHD) risk and/or mixed dyslipidemias have been treated with combination lipid-altering therapy, including combinations of statins, for reducing low-density lipoprotein cholesterol (LDL-C), with fibrates, niacin, or intestinal-acting drugs. Another combination strategy combines aspirin, a statin, three anti-hypertensives and folic acid in one pill for patients with vascular disease and those over the age of 55 years. The objective of this 'PolypilF is to simultaneously reduce four key cardiovascular risk factors: LDL cholesterol, blood pressure, serum homocysteine and platelet function. Other examples of combination therapies include: beta-blockers and ACE inhibitors; Caduet®, a combination of Lipitor® and Norvasc®; Enbrel® and methotrexate; and a Zocor®/Zetia® single pill combination. This product merges a first generation statin with a novel intestinal cholesterol absorption inhibitor. Another example is Lipitor® (atorvastatin) in combination with torcetrapib for the treatment of dyslipidaemia. Torcetrapib is a member of the cholesteryl ester transfer protein (CETP) inhibitor class of drugs for dyslipidaemia and has a different but complementary mode of action to statins. 2. Methods of Manufacture LDE compounds and compositions of the invention may be prepared by any means available in the art, including those described, e.g., in Maranhao, R.C. et al., Cancer Research 54:4660-4666 (1994); Hirata, R.D.C. et al., Biochimica et Biophysica Acta 1437:53-62 (1999); Maranhao, R.C. et al., Brazilian J. MedBiol. Res. 25:1003-1007 (1992); Maranhao, R.C. etal., Lipids 32:627-633 (1997); Maranhao, R.C. et al., Lipids 28:691-696 (1993); and U.S. Patent Nos. 5,874,059 and 5,578,583, and references cited therein. In certain embodiments, an LDE composition of the invention is prepared by combining an LDE with a therapeutic agent via sonication, ultrasound treatment. In a novel method provided by the invention, an LDE composition of the invention is prepared or manufactured by homogenizing an LDE in the presence of a therapeutic agent. Homogenization may be performed in addition to or instead of sonication or ultrasound treatment in the manufacturing of the LDE composition. In one particular embodiment, the invention provides a novel method of preparing, producing and manufacturing LDE compounds comprising a therapeutic agent, wherein said therapeutic agent is used in the treatment of a cardiovascular disease or disorder, comprising preparing an LDE and combining said LDE with said therapeutic agent.

B. Methods of Use The unique characteristics of the present invention facilitate their use in a variety of diagnostic and therapeutic applications. LDE compounds of the invention, themselves, may be used both diagnostically and therapeutically, based, in part, upon their ability to bind endogenous or exogenous proteins and LDL receptors. These properties of LDEs also provide the basis for their use in delivering a therapeutic agent to targeted cells or tissues. In general, LDE compounds and compositions of the invention may be delivered to a subject in a free form or associated with a solid support, such as an implantable medical device. Accordingly, LDE compounds and compositions may be delivered locally or systemically, in either form. For example, a free LDE compound or composition may be delivered systemically by introduction into a subject's bloodstream or locally via introduction into a subject's respiratory tract. For further example, an LDE compound or composition associated with a solid support implanted within a blood vessel may be used for systemic delivery of a therapeutic agent, or may be used for local delivery of a therapeutic agent when implanted within a particular target tissue or organ. In certain embodiments, an LDE compound or composition of the present invention is delivered to the eye via an ocular implant device. 1. Treatment of disease and delivery of therapeutic agents to diseased cells and tissues LDE compositions comprising one or more therapeutic agents are useful in delivering therapeutic agents to a subject in need thereof. Subjects include human and non-human animals. In particular embodiments, subjects are mammals. In certain embodiments, delivery is targeted to desired cells or tissues, e.g., diseased cells, based upon the LDE's ability to bind specifically to one or more LDL receptors located on the target cells. Such methods are particularly advantageous for targeting therapeutic agents to cells having increased expression of an LDL receptor bound by the LDE, such as cancer cells, vascular smooth muscle cells, and other diseases associated with neovascularization or angiogenesis, including, e.g., cardiovascular and ocular diseases. As described in U.S. Patent No. 5,578,583 and other references cited above, LDL receptor expression is highly increased in several lineages of cancer cells, and specific receptors, including LR11 , are overexpressed in vascular smooth muscle cells and atherosclerotic lesions. Thus, in one embodiment, the invention includes a method of delivering a therapeutic agent to a subject in need thereof, comprising delivering or introducing an LDE comprising the therapeutic agent to the subject. In one specific embodiment, the invention provides a method of delivering a therapeutic agent to vascular smooth muscle cells, comprising introducing an LDE comprising the therapeutic agent to a patient. The LDE may be introduced systemically or locally, e.g., via an implantable medical device. In a related embodiment, the invention provides a method of delivering a therapeutic agent to an atherosclerotic lesion, comprising introducing a solid support to the site of the atherosclerotic lesion in a subject, wherein an LDE comprising the cardiovascular therapeutic agent is associated with the solid support. In another embodiment, the invention provides a method of delivering a therapeutic agent to the eye, comprising introducing a solid support to the eye of a subject, wherein an LDE comprising a therapeutic agent for the treatment of an ocular disease or disorder. LDE compounds and compositions may be used to treat any of a variety of diseases, including, e.g., diseases wherein affected cells express an LDL receptor or related protein. For example, LDE compounds and compositions may be used to treat restenosis, atherosclerosis, angina, arrhythmia, hypertension, thrombosis and fibrinolysis, high cholesterol, congestive heart failure, and inflammation. In certain embodiments, LDE compounds and compositions of the invention are used to treat a disease associated with neovascularization. Since smooth muscle cells represent a major cellular component in the vascular wall, sites of neovascularization are effectively targeted by compositions of the invention, which preferentially bind to smooth muscle cells, e.g., via LR11. Accordingly, compositions of the invention may be used to treat a wide range of diseases and disorders associated with or resulting from neovascularization, including, e.g., cancer, arthritis, psoriasis and ocular diseases. Examples of ocular disease that are treated using compositions and methods of the present invention include, but are not limited to, macular degeneration, diabetic retinopathy, retinoblastoma, glaucoma, and various infections and trauma to the eye region. Specific forms of diseases treated according to the invention include, but are not limited to, Stargardt's disease, Best's vitelliform macular dystrophy, Doyne's honeycomb retinal dystrophy, Sorsby's fundus dystrophy, Malattia levintinese, Fundus flavimaculatus, and autosomal dominant hemorrhagic macular dystrophy. Compounds and compositions of the invention may be delivered by any means available in the art, including, e.g., by direct inhalation, by direct injection or by use of a catheter, infusion pump or stent. Other routes of delivery include, but are not limited to, intra vascular, intramuscular, subcutaneous or joint injection or surgical implantation, aerosol inhalation, oral (tablet or pill form), topical, systemic, ocular, intraperitoneal and/or intrathecal delivery. In certain embodiments, the pharmaceutical compositions may be delivered by intranasal sprays, inhalation, and/or other aerosol delivery vehicles. Methods for delivering therapeutic agents directly to the lungs via nasal aerosol sprays has been described, e.g., in U. S. Patent 5,756,353 and U. S. Patent 5,804,212. Likewise, illustrative transmucosal drug delivery in the form of a polytetrafluoroetheylene support matrix is described in U. S. Patent 5,780,045. In particular embodiments, pharmaceutical compositions of the present invention are delivered in eye drops.

2. Diagnosing the presence and progression of disease The LDE's ability to bind to LDL receptors and LDL receptor related proteins allows them to be used in determining whether and where such receptors are being expressed, underexpressed, and/or overexpressed, thus providing a basis for their use in diagnosing or staging a disease associated with differential or increased expression of LDL receptors or related proteins. In general, diagnostic and staging methods of the invention are based upon delivering a labeled LDE to a subject, detecting the amount of labeled LDE bound to the subject's cells or tissues, and comparing the amount of bound LDE to a control amount, to determine whether there is an increased or decreased amount of bound LDE in the subject as compared to the control. Appropriate controls may be readily determined by the skilled artisan. Examples of appropriate controls include results (i.e., amount of bound LDE) obtained using a control subject known to either have a particular disease or be free of a particular disease, and control amounts (e.g., predetermined cut-off values) identified as being associated with particular stages of a disease. Diagnostic and staging methods of the invention may be used to diagnose and stage any disease associated with alterations in expression or LDL-binding activity of an LDL receptor or LDL receptor-like protein, including, e.g., cancer and cardiovascular disease. Thus, in one embodiment, the invention provides a method for determining the presence or absence of a cardiovascular disease, comprising: delivering a composition comprising a labeled low density lipoprotein-like lipid emulsion (LDE) to a subject; detecting an amount of labeled LDE bound to the subject's vasculature; and comparing the amount of bound LDE detected to either a predetermined cut-off value or a control amount detected in a subject known to not have cardiovascular disease, wherein an increase in the amount as compared to the predetermined cut-off value or control amount is indicative of the presence of cardiovascular disease. Generally, the presence of a disease associated with overexpression of an LDL receptor or related protein is indicated by an at least two-fold, three-fold, or five-fold increase in bound LDE detected in the subject as compared to a control. Similarly, the presence of a disease associated with underexpression of an LDL receptor or related protein is indicated by an at least two-fold, three-fold, or five-fold decrease in bound LDE detected in the subject as compared to a control. Similarly, the invention includes a method of staging a cardiovascular disease, comprising: delivering a composition comprising a labeled low density lipoprotein-like lipid emulsion (LDE) to a subject; detecting an amount of labeled LDE bound to the subject's vasculature; and comparing the amount of bound LDE to one or more predetermined values, each associated with a cardiovascular disease stage, thereby determining the stage of cardiovascular disease. Detecting bound labeled LDE may be performed by any means available in the art that is suitable for the type of label being used and the area being examined. In certain embodiments, detection is performed using specialized equipment capable of visualizing and creating vessel and cell tissue images throughout all or a selected region of the body, such as, e.g., Positron Emission Tomography (PET) and Computed Tomography (CT) imaging or scanning.

3. Regulating vascular smooth muscle cell growth, differentiation, and/or migration Compositions of the invention are further used to regulate smooth muscle cell growth, proliferation, and/or differentiation. In general, a composition of the invention comprising a smooth muscle cell growth factor or growth inhibitor is delivered to a cell comprising an LDL receptor or related protein, thus stimulating or inhibiting smooth muscle cell growth, proliferation, differentiation, and/or migration. Smooth muscle cell proliferation is associated with a number of diseases and disorders, including, e.g., ocular diseases and the formation of atherosclerotic plaques. The proliferation and migration of vascular smooth muscle cells (VSMC) following endothelial injury are key events in the development of vascular occlusive disease. Following injury to the arterial wall, growth factors released from platelets, endothelium, macrophages and VSMC trigger the initiation of VSMC proliferation and migration. It has also recently been demonstrated that connective tissue growth factor (CTGF) is a growth factor for VSMC and thus plays a role in promoting VSMC proliferation, migration, and formation of extracellular matrix. CTGF is a cysteine-rich protein induced by TGF-beta. CTGF is expressed abundantly in atherosclerotic lesions but only marginally in normal vascular tissues (discussed in Fan, W.-H. ef al., European Journal of Cell Biology 79:915-923 (2000)). Thus, it is hypothesized that CTGF is a novel factor involved in the development and progression of atherosclerosis. Recent studies have demonstrated that CTGF binds specifically to the multiligand receptor, low density lipoprotein receptor-related protein/α2- macroglobulin receptor (LRP), which was previously identified as an apoE receptor (Beisiegel, U. et al., Nature 341 :162-164 (1989). Furthermore, CTGF is internalized into cells and degraded in an LRP-dependent process. Segarini, P. et al., J. Biol. Chem. 276:40659-40667 (2001 ). Accordingly, it is understood that LRP is a receptor for CTGF and, thus, plays an important role in CTGF biology. Since the LDE recruits apoE and binds to apoE receptors, such as LDLR and LRP, the present invention contemplates compositions and methods of regulating SMC proliferation and migration by providing to such cells an LDE composition of the invention comprising a SMC growth factor or SMC growth inhibitor. While the invention encompasses the use of any SMC growth factor or inhibitor, in certain embodiments, the SMC growth factor is CTGF, TGF-beta 1 , or a related polypeptide. Similarly, in certain embodiments, the SMC growth inhibitor is a CTGF fragment or dominant-negative mutant. Such methods and compositions may be further used in the treatment or prevention of vascular diseases, such as atherosclerosis and various ocular diseases. Thus, in one embodiment, the invention includes a composition comprising an LDE, wherein said LDE comprises a vascular smooth muscle cell (VSMC) growth factor, or a fragment, variant, or inhibitor thereof, and wherein said LDE binds an LRP. In particular embodiments, the VSMC growth factor is CTGF or TGF beta 1. Similarly, the invention includes a method of stimulating vascular smooth muscle cell growth and/or migration, comprising: delivering a composition comprising a labeled LDE to a subject, wherein said LDE comprises a vascular smooth muscle cell (VSMC) growth factor, or a fragment or variant thereof, and wherein said LDE binds an LRP. The invention also includes a method of inhibiting vascular smooth muscle cell growth and/or migration, comprising delivering a composition comprising an LDE to a subject, wherein said LDE comprises an inhibitor of a vascular smooth muscle cell (VSMC) growth factor, and wherein said LDE binds an LRP. While the invention may be used in the treatment of any disease or disorder associated with irregular SMC growth/proliferation and/or migration, specific examples of such disease that are treated according to the invention include, but are not limited to, cancer, arthritis, psoriasis, and ocular diseases. Examples of ocular diseases treated according to the present invention include, but are not limited to, macular degeneration; neoplasias, e.g., retinoblastoma; diabetic retinopathy; open angle glaucoma; and various infections and trauma, e.g., to the cornea. In one embodiment, methods of the invention are used to treat peripheral vascular diseases, such as an aneurism. Accordingly, the invention includes a method of treating a patient diagnosed with or suspected of having restenosis or atherosclerosis, comprising delivering to said patient a composition comprising an LDE, wherein said LDE comprises an inhibitor of a vascular smooth muscle cell (VSMC) growth factor, and wherein said LDE binds an LDL-receptor related protein (LRP). The invention further provides a method of treating a patient diagnosed with or suspected of having a peripheral vascular disease, comprising: delivering to said patient a composition comprising an LDE wherein said LDE comprises a vascular smooth muscle cell (VSMC) growth factor, or a fragment or variant thereof, and wherein said LDE binds an LDL-receptor related protein (LRP). In one embodiment, the method is employed to treat an aneurism. In one embodiment, methods of the invention are used to treat ocular diseases, such as, e.g., macular degeneration and diabetic retinopathy. Accordingly, the invention includes a method of treating a patient diagnosed with or suspected of having macular degeneration or diabetic retinopathy (or any other ocular disease), comprising delivering to said patient a composition comprising an LDE, wherein said LDE comprises an inhibitor of a vascular smooth muscle cell (VSMC) growth factor, and wherein said LDE binds an LDL-receptor related protein (LRP). The compositions may be associated with an implantable medical device, or other solid support, as described above, and is, thus, particularly suited for the localized treatment of restenosis, atherosclerosis, or ocular diseases, wherein a composition comprising an LDE containing an inhibitor of a vascular smooth muscle cell (VSMC) growth factor is associated with a solid support, which is implanted at a site of lesion or disease in a subject in need thereof. In one embodiment, the invention includes an implantable medical device or other solid support of the invention includes an LDE composition comprising CTGF.

4. Promoting cholesterol efflux and lipoprotein capture LDE compounds and compositions of the invention are also useful in promoting cholesterol efflux, and, therefore, preventing and treating atherosclerosis. The majority of blood lipids are transported in plasma bound to lipoprotein particles. Lipoproteins are high molecular weight carriers of plasma cholesterol and triglycerides, typically in the form of cholesteryl esters. They are micellar lipid-protein complexes that comprise one or more proteins associated with polar lipids surrounding a cholesterol-containing core. Five major density classes of lipoproteins have been recognized: chylomicrons, very low-density lipoproteins (VLDL), intermediate density lipoprotein (IDL) low-density lipoproteins (LDL) and high-density lipoproteins (HDL). The lipid-poor apolipoprotein A-1 has been shown to reduce progression of and even induce regression of atherosclerosis, via a mechanism involving promoting cholesterol efflux from peripheral cells, including, e.g., macrophages, and returning it to the liver for excretion, a process termed reverse cholesterol transport, as described in further detail in Rader, D.J., Am. J. Cardiol. 2003;92(suppl):42J-49J. The invention provides a novel mechanism of promoting cholesterol efflux, i.e., by introducing an LDE into the bloodstream. Without wishing to be bound to any particular theory, it is understood that the LDE binds free cholesterol and/or cholesterol associated with peripheral cells and transports it to the liver. Thus, in one embodiment, the invention includes a method of treating a patient having a cardiovascular disease or disorder, comprising delivering to said patient a composition comprising an LDE, wherein said LDE promotes cholesterol efflux from peripheral cells, such as macrophages. Given that the LDE binds apolipoprotein, the invention further provides a method of capturing apolipoprotein present in a subject's plasma, comprising delivering an LDE to the subject's bloodstream. In addition, the invention includes a method of removing a polypeptide from a lipoprotein present in a subject's plasma, comprising delivering an LDE to the subject's bloodstream, wherein said LDE competes with lipoproteins, chylomicrons and other protein- binding lipids for binding the polypeptide. In certain embodiments, the LDE may be associated with a solid support. All of the above U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non- patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety.

EXAMPLES EXAMPLE 1 PREPARATION AND CHARACTERIZATION OF LDE LDE was prepared from a lipid mixture composed of 40 mg egg phosphatidylcholine (PC), 20 mg cholesteryl oleate (CO), 1 mg triolein (TO) and 0.5 mg cholesterol (chol), corresponding to 65% PC, 32.5% CO, 1.6% TO and 0.8% chol. Lipids were dissolved in 10 ml chloroform/methanol (2:1) at concentrations of 100 mg/ml for CO, 50 mg/ml for chol, and 40 mg/ml for TO (PC was purchased in solution). The solvent was removed under N₂ stream and the lipids were dried overnight at 4 °C in a vacuum desiccator. The lipids were hydrated with 10 ml of 0.9% saline solution in a 20 ml vial (lipid concentration approximately 6 mg/ml), and sonicated for 3 hrs with a Branson sonicator (model 450, cm titanium flat tip probe) at 125 W in continuous operating mode under N₂ atmosphere. The temperature was maintained between 50-55 ^°C (10 °C above the phase transition temperature of CO). A RT water bath was used for cooling when sample became too warm. The LDE emulsion was subsequently centrifuged at 4 °C for 30 min at 210000 xg_max (35000 rpm) using a Beckman ultracentrifuge in conjunction with a SW41 rotor. The top 10% (1 ml) of the emulsion was aspirated off and discarded. The particle size was determined by dynamic light scattering as varying between 45 and 55 nm in diameter. In some instances, the samples were concentrated by potassium bromide gradient ultracentrifugation and potassium bromide was subsequently removed by dilaysis. LDE was passed through a 0.22- μm filter for sterilization.

EXAMPLE 2 INCORPORATION OF PACLITAXEL OLEATE INTO LDE AND CHARACTERIZATION OF THE LDE-DRUG COMPLEX

Paclitaxel oleate was incorporated into LDE by adding 34 mg of paclitaxel oleate dissolved in 1.2 ml ethanol (28.3 mg/ml) to 2.8 ml LDE (46.7 mg/ml) at a paclitaxel oleate-to-lipid ratio of 0.26 mg/mg. The ethanol-containing emulsion (40% (v/v)) was sonicated for 30 min at 70 °C using a Branson Sonifier model 450 equipped with a 1 cm titanium flat tip probe. Unincorporated paclitaxel oleate was removed by centrifugation at 3000 rpm for 15 minutes. The incorporation efficiency was 70-75% with a final drug-to-lipid ratio of 0.18-0.2 mg/mg (0.125 mol/mol). Incorporation efficiency was 95% and was determined by HPLC and also by radioactivity count of the radiolabeled components. The particle size was determined by dynamic light scattering, revealing an increase in size of about 10% when compared with the LDE without drug. The emulsion was filter- sterilized by filtration through a 0.22-μm filter. It was determined that each ml of LDE solubilized 4.8-5.4 mg of paclitaxel oleate. EXAMPLE 3 REDUCTION OF NEOINTIMAL HYPERPLASIA IN ATHEROSCLEROSIS INDUCED RABBITS BY SYSTEMIC DELIVERY OF LDE-PACLITAXEL OLEATE

The association of paclitaxel oleate with LDE forms a stable complex that binds to the low-density lipoprotein (LDL) receptors. As certain proliferative diseases overexpress these receptors, the complex can be used as a method of targeting these cells. This Example demonstrates the ability of the LDE:Paclitaxel oleate complex to inhibit vascular smooth muscle cell proliferation in an animal model of atherosclerosis. Male rabbits weighting 2.7 - 3.0 kg were fed a cholesterol rich diet for 2 months and divided into 2 groups (treated and control). After 1 month of diet, the treated group of animals was injected with LDE:Paclitaxel oleate (4mg/kg) intravenously (4 doses/month). Both groups were daily monitored for weight variation, and blood samples collected once a week for analysis. After 2 months, both animal groups were sacrificed, and the aortas were harvested for macro and microscopic analysis and lesion size measurements. Blood laboratory analysis demonstrated no hemogram alteration in either groups. However in regards to weight, the control group showed a significant 35% in weight reduction when compared with the treated group. Arterial analysis revealed a reduction of intimal thickness in the treated group compared to the control group (1.4 x 10⁵ and 8.8 x 10⁵ μm² and 40 and 184 μm, respectively), as shown in Figure 1. This data clearly demonstrates that treatment with LDE:Paclitaxel oleate reduces neointimal hyperplasia, and provides evidence of low toxicity. EXAMPLE 4 TGF β1 REGULATION OF VASCULAR SMOOTH MUSCLE PROLIFERATION AND FIBROSIS

This Example demonstrates that, in a dose dependent manner, TGF- βl increases proliferation of vascular smooth muscle cells. Vascular smooth muscle cells (VSMC) obtained from bovine aortas were cultured at a density of 10,000 cells/cm² (20,000 cells per 24 well culture plate). Increasing doses of TGF-β1 or GM-CSF were added, and the cells were cultured for 24 hours. After washing, ³[H]-thymidine incorporation was measured, as an indicator of DNA synthesis and an index of cell proliferation. As shown in Figure 2A, TGF-β1 caused an 8-fold increase within 24 hours of incubation with VSMC. GM-CSF, a cytokine expected to enhance the connective tissue effects of TGF-β1 , increased ³[H]-thymidine 0.3 fold, as shown in Figure 3B. In addition, an assay measuring 3-(4,5-diethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT assay), which measures cell activity and correlates with the number of viable cells, showed that the number of viable cells was increased by TGF-β1 in a dose- dependent manner (data not shown). These findings demonstrate that even small quantities of TGF-β1 (0.1 ng/ml) induced hyperplasia of VSMC. In contrast, GM-CSF had a minimal effect on the proliferation of VSMC. Additional data not shown demonstrated that the concomitant presence of TGF-β1 and GM-CSF did not result in augmented proliferation of VSMCs, although the presence of GM-CSF augmented collagen I synthesis mediated by TGF-β1. In addition, the presence of TGF-β1 in a dose dependent fashion increases synthesis of collagen III and fibronectin. To determine the effect of smooth muscle cell injury on TGF-β1 release, VSMCs were plated at a density of 10,000 cells cm² in DMEM with 10% fetal calf serum and grown to confluence, then changed to serum-free DMEM containing 1 g/l insulin, 0.67 mg/l sodium selenium, 0.55 g/l transferring, and 0.2 g/l ethanolamine for 2 days. Each monolayer was mechanically wounded by 18 scrapes using a plastic cell scraper, then washed with the serum-free DMEM and cultured with fresh serum-free DMEM. TGF-β1 in the conditioned media was quantitated using an ELISA. Active TGF-β1 was determined as TGF-β1 released in a biologically active form, and total TGF-β1 was determined as the total of active and latent TGF-β1 present in the CM. As shown in Figure 3, these findings demonstrate that injury to VSMCs results in release of the potent fibrogenic cytokine, TGF-β1. As shown above, wounding of monolayers of vascular smooth muscle cells spontaneously releases an active form of TGF-β1. To determine the effect of TGF-β1 on wound healing, wound areas were measured 24 hours after wounding. As shown in Figure 4, the presence of TGF-β1 decreased the area of wounds in monolayers of VSMCs at a faster rate than when no TGF-β1 was present. These findings demonstrate that in the presence of TGF-β1 , VSMCs are likely to proliferate and enclose or fill in any gaps created by the presence of an injury, such as that may occur with insertion of a prosthesis or other medical device. The addition of GM-CSF concomitantly with TGF-β1 to wounds of in vitro monolayers of VSMC led to increased repair by proliferation of VSMCs. To determine the role of connective tissue synthesis in this process, VSMCs obtained from bovine aortas were cultured at a density of 10,000 cells/cm² (20,000 cells per 24 well culture plate). Increasing doses of TGF-β1 or GM-CSF were added, as indicated in Figure 5, and the cells were cultured for 24 hours. After washing, the VSMCs were collected for protein extraction and western analysis for collagen III and fibronectin. The results shown in Figure 5 demonstrate that, in a dose- dependent manner, the presence of TGF-β1 augments fibronectin synthesis. These findings suggest that the presence of TGF-β1 , with or without GM-CSF, induces connective tissue synthesis and stabilizes any prosthetic material implanted in a vessel.

EXAMPLE 5 STABILITY OF THE LDE-PACLITAXEL OLEATE COMPLEX IN VITRO The stability of LDE-paclitaxel oleate was tested by membrane dialysis (12,000 MW cut-off) against human plasma and Tris-HCI solution, pH 7.4. One milliliter of labeled [¹⁴C]-cholesteryl oleate-LDE:[³H]-paclitaxel oleate was dialyzed against 20 ml of human plasma or Tris-HCI solution. Samples of 5 ml were collected from the dialysis bag at 0.03-168 h intervals and placed separately into vials with 7 ml scintillation solution. The radioactivity was measured by liquid scintillation spectrometry using a Packard 1600 TR model liquid scintillation counter. As shown in Figure 6, during the first 24 h, only negligible dissociation of the complex occurred regardless whether plasma or Tris buffer was used. In the ensuing 24-168 h, there was some minor dissociation of the complex, which was less in Tris buffer than in plasma. After incubation with plasma, 97.8% of the LDE radioactive label and 98.4% of the paclitaxel oleate label were found at the lipoprotein-containing plasma fraction, whereas 2.2% and 1.6% of the two labels, respectively, were found at the lipoprotein-deficient fraction. Therefore, only residual amounts of drug leaked out of the microemulsion, and is found in the fraction that contains mainly albumin, globulins, and a-glycoprotein. Furthermore, plasma kinetic analysis of LDE-paclitaxel oleate demonstrated that this period of time is sufficient for most of the complex to be removed from the plasma compartment. These results demonstrate that LDE-paclitaxel oleate is a stable drug formulation with improved pharmacokinetic properties.

EXAMPLE 6 CELL GROWTH INHIBITION BY LDE-PACLITAXEL OLEATE

To determine the growth inhibitory effect of LDE-paclitaxel oleate, NCI H292 cells were harvested from culture and distributed into 96-well culture plates at 10⁵ cells/well. After 24 h incubation, serial dilutions of a Cremophor/EL stock solution of paclitaxel oleate or paclitaxel or LDE-pactitaxel oleate were added to the wells in triplicate. The final concentrations of paclitaxel or paclitaxel oleate (0.003-3 μM) and LDE-paclitaxel oleate (0.0001-10 μM) were used. The cells were incubated an additional 72 h. Atthe end of this time period, the medium was removed and the number of living cells was determined by the colorimetric MTT assay. The 50% inhibitory concentration (IC₅₀) was determined as the drug concentration required to inhibit 50% of the cell growth. Figure 7A shows the dose-response curves of the cytostatic activity of paclitaxel oleate and of paclitaxel, both using Cremophor as solubilizing agent. These data demonstrate that the chemical modification of the drug does not affect the cytostatic activity of the drug (p=0.523). The cytostatic index of paclitaxel oleate (IC₅₀=0.11 μM) and paclitaxel (IC₅₀=0.11 μM) are also similar. Figure 7B shows the cytostatic activity curves of LDE-paclitaxel oleate, paclitaxel oleate solubilized in Cremophor and, finally, of LDE-paclitaxel oleate with addition of Cremophor, in order to discriminate the additive cytotoxicity of Cremophor. LDE-paclitaxel oleate had a clear-cut lower cytotoxicity than paclitaxel oleate solubilized in Cremophor (IC₅o=1.00 μM and 0.09 μM, respectively, p=0.015). When Cremophor is added to LDE-paclitaxel oleate incubates, the cytotoxicity increased (IC₅o=0.15 μM, p=0.756), so that the IC₅₀ approached that of commercial paclitaxel oleate solubilized in Cremophor, indicating that the greater cytotoxicity of the commercial formulation of paclitaxel and paclitaxel oleate solubilized in Cremophor can be ascribed to the presence of

Cremophor. These results demonstrate clear advantages of lower toxicity using

LDE-paclitaxel oleate as compared to paclitaxel formulations using Cremophor.

EXAMPLE 7 COMPETITION BETWEEN LDE-PACLITAXEL OLEATE AND NATIVE LDL

To examine the role of LDL in uptake of LDE-paclitaxel oleate, NCI H292 viable cells (10⁶) were incubated for 24 h in RPMI 1640 containing antibiotics, supplemented with 10% LPDS. After this period, 200 μg/ml of [¹⁴C]- cholesteryl oleate-LDE-[³H]-paclitaxel oleate, and increasing amounts of human LDL (50-400 μg/ml), were added to the plates in duplicate and incubated for 4 h at 37 °C. The cells were then washed three times with cold PBS plus BSA and twice with PBS at 37 °C, harvested and centrifuged at 14,000 rpm for 15 min; 200 μl of NaOH 0.1 M were added to the pellet to disrupt the cell pellet under vortex mixing before radioactivity measurement. As shown in Figure 8A, when cells were incubated with increasing amounts of LDE-paclitaxel oleate labeled with [³H]-paclitaxel oleate and [¹⁴C]- cholesteryl oleate, there was a proportionally increasing uptake of the two labels and the two uptake curves are similar (p=0.2717), indicating that both paclitaxel and cholesteryl oleate components of the complex are simultaneously internalized into the cells. As shown in Figure 8B, the addition of increasing amounts of native human LDL to the incubates of LDE-paclitaxel oleate and the malignant cells led to a progressive diminution of cell uptake of both [³H]-paclitaxel oleate and [¹⁴C]- cholesteryl oleate contained in the LDE. This indicates that when LDE uptake is diminished by the competition of native LDL, the cell uptake of the drug associated with the LDE is also proportionally diminished, further establishing that the LDE may be used to target delivery of drug to cells comprising LDL receptors.

From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.

Claims

1. A composition adapted for cardiovascular delivery, comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises a therapeutic agent, and wherein said therapeutic agent is used in the treatment of a cardiovascular disease or disorder.

2. A composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises a therapeutic agent, wherein said LDE binds a low density lipoprotein receptor (LDLR), and wherein overexpression of said LDLR is associated with a cardiovascular disease or disorder.

3. The composition of claim 2, wherein said LDLR is LR11.

4. The composition of claim 1 or 2, wherein said LDE comprises a hydrophobic core surrounded by a monolayer of phospholipids.

5. The composition of claim 4, further comprising cholesterol in said monolayer of phospholipids.

6. The composition of claim 4, further comprising a surfactant in said monolayer of phospholipids.

7. The composition of claim 4 or 5, wherein said hydrophobic core consists essentially of cholesterol esters, triglycerides, or mixtures thereof.

8. The composition of claim 7, wherein said hydrophobic core consists essentially of cholesterol esters.

9. The composition of claim 7 or 8, wherein the phospholipids comprise 10-70% (by weight) of said LDE and the cholesterol esters comprise 10-90% (by weight)of said LDE.

10. The composition of claim 7, wherein the phospholipids comprise 10- 70% (by weight) of said LDE and the triglycerides comprise 10-90% (by weight) of said LDE.

11. The composition of claim 4 or 5, wherein the phospholipid is egg or soy phosphatidylcholine and the core is composed of a mixture of cholesterol oleate and triolein.

12. The composition of claim 11 , wherein said LDE comprises phosphatidylcholine:cholesterol oleate:triolein:cholesterol at a ratio of 65%:33%:2%:1 % (by weight).

13. The composition of claim 1 or 2, wherein said LDE is detectably labeled.

14. The composition of claim 13, wherein said LDE is labeled with a radioactive label.

15. The composition of claim 14, wherein said LDE is labeled with a detectable label selected from the group consisting of: [¹⁴C]cholesterol oleate, [³H]cholesterol oleate, [³H]triolein, [³H]cholesterol, ^99mTc, ²³l, ¹³¹l, ³²P, ¹⁹²lr¹⁰³Pd, ⁹⁸Au ¹¹¹ln, ⁶⁷Ga, ²⁰¹TI, ¹⁵³Sm, ¹⁸F and ⁹⁰Sr.

16. The composition of claim 1 or 2, wherein said therapeutic agent is hydrophobic.

17. The composition of claim 1 or 2, wherein said therapeutic agent is selected from the group consisting of: antianginal agents, antiarrhythmic agents, antihypertensive agents, antithrombotic and fibrinolytic agents, blood lipid-lowering agents, congestive heart failure drugs, anti-inflammatory agents, inflammatory agents, angiogenic agents, anti-angiogenic agents, growth factors, isotopes, cell growth inhibitors, and cell growth stimulators.

18. The composition of claim 17, wherein said antianginal agents are selected from the group consisting of: organonitrates, calcium channel blockers, and beta-adrenergic antagonists.

19. The composition of claim 17, wherein said antiarrhythmic agents are selected from the group consisting of: sodium channel blockers, beta-adrenergic blockers, repolarization drugs, calcium channel blockers, adenosine, and digoxin.

20. The composition of claim 17, wherein said antihypertensive agents are selected from the group consisting of: alphai-ad renergic antagonists, beta- adrenergic antagonists, combined alpha/beta-adrenergic antagonists, adrenergic neuron blocking agents, CNS-acting antihypertensives, anti-angiotensin II agents, calcium channel blockers, diuretics, and direct vasodilators.

21. The composition of claim 17, wherein said antithrombotic and fibrinolytic agents are selected from the group consisting of: anticoagulants, anticoagulant antagonists, antiplatelet agents, thrombolytic agents, and thrombolytic agent antagonists.

22. The composition of claim 17, wherein said blood lipid-lowering agents are selected from the group consisting of: resins, HMG CoA reductase inhibitors, fibric acid derivatives, nicotinic acid and probucol.

23. The composition of claim 17, wherein said congestive heart failure drugs are selected from the group consisting of: inotropic agents, angiotensin antagonists, diuretics, combined afterioad-preload reduction drugs, and beta-adrenergic blockers.

24. The composition of claim 17, wherein said anti-inflammatory agents are selected from the group consisting of: steroid anti-inflammatory agents, including bethametasone, cortisone, hydrocortisone, dexametasone, methylprednisolone, prednisolone, prednisone, and triacinolone, and non-steroid anti-inflammatory agents, including salicylates, p-aminophenols, iondoles, heteroaryl acetic acids, arylpropionic acids, and enolic acids.

25. The composition of claim 1 or 2, wherein said therapeutic agent is paclitaxel or an analog or derivative thereof.

26. The composition of claim 25, wherein said therapeutic agent is paclitaxel oleate.

27. The composition of claim 1 or 2, wherein said therapeutic agent is a peptide or polypeptide.

28. The composition of claim 1 or 2, wherein said therapeutic agent is a radiopharmaceutical or fluorescently labeled compound or single radioactive seeds.

29. The composition of claim 1 or 2, further comprising a polypeptide.

30. The composition of claim 29, wherein said polypeptide is an apolipoprotein.

31. The composition of claim 30, wherein said apolipoprotein is apolipoprotein E.

32. The composition of claim 1 or 2, further comprising a pharmaceutically acceptable excipient.

33. The composition of claim 1 or 2, further comprising a solid support, wherein said lipid emulsion is associated with the solid support.

34. The composition of claim 33, wherein said solid support is an implantable medical device.

35. The composition of claim 34, wherein said implantable medical device is selected from the group consisting of: balloons, stents, coils, and tissue engineering scaffolds.

36. The composition of claim 1 or 2, further comprising at least one additional therapeutic agent, wherein said additional therapeutic agent is used in the treatment of a cardiovascular disease or disorder.

37. An implantable medical device, wherein said device comprises a solid support and a low density lipoprotein-like lipid emulsion (LDE).

38. The medical device of claim 37, wherein said solid support is coated with said LDE.

39. The medical device of claim 37, wherein said LDE comprises a therapeutic agent.

40. The medical device of claim 39, wherein said therapeutic agent is used in the treatment of a cardiovascular disease or disorder.

41. The medical device of claim 39, wherein said therapeutic agent is paclitaxel or an analog or derivative thereof.

42. The medical device of claim 41 , wherein said therapeutic agent is paclitaxel oleate.

43. The medical device of claim 39, wherein said solid support is selected from the group consisting of: balloons, stents, coils, and tissue engineering scaffolds.

44. The medical device of claim 39, wherein said LDE further comprises at least one additional therapeutic agent.

45. A method of delivering a cardiovascular therapeutic agent to a patient, comprising introducing to the patient a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises a cardiovascular therapeutic agent.

46. The method of claim 45, wherein said LDE binds a low density lipoprotein receptor (LDLR) and wherein said cardiovascular therapeutic agent is selectively delivered to cells expressing the LDLR.

47. The method of claim 46, wherein said LDLR is LR11.

48. The method of claim 45 or 46, wherein said cardiovascular therapeutic agent is hydrophobic.

49. The method of claim 45 or 46, wherein said therapeutic agent is selected from the group consisting of: antianginal agents, antiarrhythmic agents, antihypertensive agents, antithrombotic and fibrinolytic agents, blood lipid-lowering agents, congestive heart failure drugs, anti-inflammatory agents, inflammatory agents, growth factors, isotopes, cell growth inhibitors, and cell growth stimulators.

50. The method of claim 45 or 46, wherein said therapeutic agent is paclitaxel or an analog or derivative thereof.

51. The method of claim 50, wherein said therapeutic agent is paclitaxel oleate.

52. The method of claim 45 or 46, wherein said patient has been diagnosed with or is suspected of having a cardiovascular disease.

53. The method of claim 52, wherein said cardiovascular disease is selected from the group consisting of: restenosis, atherosclerosis, coronary heart disease, lipidemia, and peripheral vascular diseases, including aneurisms.

54. A method for determining the presence or absence of a cardiovascular disease, comprising: (a) delivering a composition comprising a labeled low density lipoprotein-like lipid emulsion (LDE) to a subject; (b) detecting an amount of labeled LDE bound to the subject's vasculature; and comparing the amount of bound LDE detected in step (b) to either a predetermined cut-off value or a control amount detected in a subject known to not have cardiovascular disease, wherein an increase in the amount as compared to the predetermined cut-off value or control amount is indicative of the presence of cardiovascular disease.

55. A method of staging a cardiovascular disease, comprising: (a) delivering a composition comprising a labeled low density lipoprotein-like lipid emulsion (LDE) to a subject; (b) detecting an amount of labeled LDE bound to the subject's vasculature; and comparing the amount of bound LDE detected in step (b) to one or more predetermined values, each associated with a cardiovascular disease stage, thereby determining the stage of cardiovascular disease.

56. The method of claim 54 or 55, wherein said LDE binds LR11.

57. The method of claim 54 or 55, wherein said LDE is delivered to the subject's bloodstream.

58. The method of claim 54 or 55, wherein said labeled LDE is associated with a solid support, and wherein said labeled LDE is delivered by implanting the solid support into the subject.

59. A method of delivering a cardiovascular therapeutic agent to an atherosclerotic lesion, comprising introducing a solid support to the site of the atherosclerotic lesion in a subject, wherein a low density lipoprotein-like lipid emulsion (LDE) comprising the cardiovascular therapeutic agent is associated with the solid support.

60. The method of claim 59, wherein the LDE binds a low density lipid receptor overexpressed in the atherosclerotic lesion.

61. The method of claim 59, wherein the solid support is an implantable medical device.

62. The method of claim 59, wherein the cardiovascular therapeutic agent is selected from the group consisting of: antianginal agents, antiarrhythmic agents, antihypertensive agents, antithrombotic and fibrinolytic agents, blood lipid- lowering agents, congestive heart failure drugs, anti-inflammatory agents, inflammatory agents, growth factors, isotopes, cell growth inhibitors, and cell growth stimulators.

63. The method of claim 59, wherein said cardiovascular therapeutic agent is paclitaxel or an analog or derivative thereof.

64. The method of claim 63, wherein said cardiovascular therapeutic agent is paclitaxel oleate.

65. A method of capturing apolipoprotein present in a subject's plasma, comprising delivering a low density lipoprotein-like lipid emulsion (LDE) to the subject's bloodstream, wherein said LDE binds apolipoprotein.

66. A method of removing a polypeptide from a lipoprotein present in a subject's plasma, comprising delivering a low density lipoprotein-like lipid emulsion (LDE) to the subject's bloodstream, wherein said LDE competes with lipoproteins, chylomicrons and other protein-binding lipids for binding the polypeptide.

67. The method of claim 66, wherein the polypeptide is apolipoprotein E.

68. The method of claim 65 or 66, wherein said LDE comprises a hydrophobic core surrounded by a monolayer of phospholipids.

69. A composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises a vascular smooth muscle cell (VSMC) growth factor, or a fragment, variant, or inhibitor thereof, and wherein said LDE binds an LDL-receptor related protein (LRP).

70. The composition of claim 69, wherein said growth factor is connective tissue growth factor (CTGF).

71. The composition of claim 69, wherein said LDE binds a VSMC.

72. A method of stimulating vascular smooth muscle cell growth and/or migration, comprising: delivering a composition comprising a low density lipoprotein-like lipid emulsion (LDE) to a subject, wherein said LDE comprises a vascular smooth muscle cell (VSMC) growth factor, or a fragment or variant thereof, and wherein said LDE binds an LDL-receptor related protein (LRP).

73. A method of inhibiting vascular smooth muscle cell growth and/or migration, comprising delivering a composition comprising a low density lipoprotein-like lipid emulsion (LDE) to a subject, wherein said LDE comprises an inhibitorof a vascular smooth muscle cell (VSMC) growth factor, and wherein said LDE binds an LDL-receptor related protein (LRP).

74. The method of claim 72 or 73, wherein said VSMC growth factor is connective tissue growth factor.

75. A method of treating a patient diagnosed with or suspected of having a peripheral vascular disease, comprising: delivering to said patient a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises a vascular smooth muscle cell (VSMC) growth factor, or a fragment or variant thereof, and wherein said LDE binds an LDL-receptor related protein (LRP).

76. The method of claim 75, wherein said disease is an aneurism.

77. The method of claim 75, wherein said LDE is associated with an implantable medical device.

78. A method of treating a patient diagnosed with or suspected of having restenosis or atherosclerosis, comprising delivering to said patient a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises an inhibitor of a vascular smooth muscle cell (VSMC) growth factor, and wherein said LDE binds an LDL-receptor related protein (LRP).

79. The method of claim 78, wherein said LDE is associated with an implantable medical device.

80. The method of claim 75 or 78, wherein said VSMC growth factor is connective tissue growth factor.

81. A method of treating a patient having a cardiovascular disease or disorder, comprising delivering to said patient a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE promotes cholesterol efflux from macrophages.

82. A process for producing a low density lipoprotein-like lipid emulsion (LDE) comprising a therapeutic agent, wherein said therapeutic agent is used in the treatment of a cardiovascular disease or disorder, comprising: (a) preparing an LDE; and (b) combining said LDE with said therapeutic agent.

83. The process of claim 82, wherein said combining is performed by one of the following procedures: sonication, ultrasound treatment, and homogenization.

84. A process for producing a low density lipoprotein-like lipid emulsion (LDE) comprising a therapeutic agent, comprising: (a) preparing an LDE; and (b) homogenizing said LDE in the presence of said therapeutic agent.

85. A method of treating a patient diagnosed with or suspected of having a disease associated with neovascularization, comprising: delivering to said patient a composition comprising a low density lipoprotein-like lipid emulsion (LDE), wherein said LDE comprises an inhibitorof blood vessel growth, and wherein said LDE binds an LDL-receptor related protein (LRP).

86. The method of claim 85, wherein said disease is selected from the group consisting of: arthritis, psoriasis and ocular disease.

87. The method of claim 86, wherein said ocular disease is macular degeneration.

88. The method of claim 86, wherein said ocular disease is diabetic retinopathy.

89. The method of claim 86, wherein said ocular disease is glaucoma.

90. The method of claim 85, wherein said composition is provided topically.

91. The method of claim 85, wherein said composition is provided systemically.

92. The method of claim 85, wherein said composition is associated with an implantable medical device.

93. The method of claim 85, wherein said inhibitor of blood vessel growth is an inhibitor of angiogenesis.

94. The method of claim 93, wherein said inhibitor targets an angiogenic factor selected from the group consisting of: angiopoietin-1 , basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF).

95. The method of claim 93, wherein said inhibitor is a statin.

96. The method of claim 94, wherein said statin is angiostatin or endostatin.