IL91572A - Pharmaceutical compositions for treating conditions appearing after vascular damage comprising ace inhibitors - Google Patents

Abstract

ACE inhibitors are able to suppress the formation of neointima and the reduction of the vessel volume owing to vessel wall thickening after a vessel injury. They are accordingly suitable for the treatment and prevention of neointima formation after vessel injury, in particular for the prevention of arterial restenosis after angioplasty or of vessel wall thickening after vascular surgery in arteries and veins.

Description

ny DQ niQiAjn mya-in-i i ^oi? niripn ^ eon Pharmaceutical compositions' for treating conditions appearing after vascular damage comprising ACE inhibitors HOFFMANN-LA ROCHE 78375 RAN 4019/105 In the scope of the present invention it has been established that ACE inhibitors suppress the formation of \ neointima and the reduction of the vascular lumen by vascular wall thickening after vascular damage.

Q The increase of smooth muscle tissue by proliferation and the formation of an extracellular matrix are the main processes which lead to a thickening of the vascular wall and finally to vascular closure in the case of arteriosclerosis (including atherosclerosis) or after vascular 5 surgery or forcible vascular opening after vascular stenosis or closure, e.g. after a cardiac infarct. These processes, which take place when vessels grow during development and as a response to a vasodilation or vascular damage, are normally harmless. However, when they 0 are excessive, they lead to the narrowing of arteries and therewith to increased morbidity, i.e. disease in the widest sense.

The proliferation of smooth muscle cells in the 5 vascular wall takes place in the early phase of healing after damage to the endothelium, i.e. to the cell layer lining the blood vessel on the inner side. Thus, for example, in the carotid artery of a rat the transition of the cells from a dormant state into a growing state 0 finishes essentially within 24 hours. The proliferation is intensified by continued growth and mitosis of the descendents of these originally stimulated cells.1 The Laboratory Investigation 49., 327-333 (1983) Kbr/12.7.89 growth factors as well as other mechanisms by which hitherto dormant smooth muscle cells are caused to undergo nuclear division are not known or are only insufficiently known. It is known only that the growth of smooth muscle cells in vitro is increased by growth factors from the blood platelets, but their role in vivo is still not clear .2 After damage, in the widest sense after any disturbance of the vascular endothelium or of the vessel wall, the smooth muscle cells of the media of the vessel wall are caused to enter into the growing state, i.e. to proliferate and to produce extracellular matrix. In addition to the synthesis of DNA and to mitosis, a portion of the smooth muscle cells migrates into the intima of the vascular wall and proliferates there. Some of the smooth muscle cells which have migrated into the intima also produce extracellular matrix and thereby contribute materially to the thickening of the vascular wall, as is observed after vascular damage. Seen in simplified terms. the course of the thickening of the intima of a damaged artery consists in an initial proliferation of the smooth muscle cells in the media, which is followed by a migration of such cells from the media into the intima. In addition, smooth muscle cells proliferate in the intima and produce extracellular matrix. Lastly, intimal proliferation and matrix formation lead to a restriction of the cross-section of the blood vessel to such an extent 3,4 that morbidity occurs The New England Journal of Medicine 314. 488-500 (1986) The New England Journal of Medicine 318. 1734-1737 (1988) 4 J Joouurrinal of the American College of Cardiology 6. 369-375 (1985) The processes which lead to the formation of neointima are based on several basic mechanisms: 1. The proliferation of the smooth muscle cells increases g their number (hyperplasia) in the media and intima. 2. Migration of smooth muscle cells from the media into the intima takes place. 3. Extracellular matrix is formed. 1Q The sum of these processes, which take place mainly in the intima. leads to the formation of neointimal tissue and therewith to an impairment of the blood flow in the blood vessel . 12 Active substances which prevent or strongly reduce these processes are of therapeutic value in a number of pathological conditions. It is known that various active substances inhibit the proliferation of smooth muscle cells in vitro, but hitherto only for heparin has it been 20 clearly possible to detect also in animal models an inhibition of the proliferation of smooth muscle cells and the formation of neointima. Indeed, the plasma concentration which is required to produce this effect in animals is 3 to 4 times higher than the therapeutically 25 conventional concentration for human beings. Furthermore, heparin can only be administered intravenously, which severely limits the duration of administration.

As mentioned above, it has been established in the 30 scope of the present invention that ACE inhibitors suppress the formation of neointima and the reduction of the vascular lumen by vascular wall thickening after vascular damage and, what is more, in concentrations which 35 5 Nature 265. 625-626 (1977) lie in the same order as those which are usual in the treatment of high blood pressure with ACE inhibitors.

It is to be expected that the suppression of the formation of neointima in accordance with the invention and the associated prevention of the reduction of the vascular lumen by vascular wall thickening after vascular damage using ACE inhibitors will be of therapeutic value in a number of clinical situations. Thereto there belong the prevention of a restenosis after percutaneous transluminal angioplasty or vascular surgery as well as the treatment or prevention of neointima formation and of vascular wall thickening in the case of arteriosclerosis and diabetic angiopathy.

The object of the present invention is the use of ACE inhibitors for the prevention of the proliferation of smooth muscle cells in the intima and/or the media, of the migration of smooth muscle cells from the media into the intima and of the formation of extracellular matrix as well as for the treatment and prevention of neointima formation, in each case after vascular damage, especially of damage caused physically, chemically or surgically, as well as of arterial restenosis after angioplasty or vascular wall thickening after vascular surgery in arteries and veins. The use of ACE inhibitors for the prophylaxis of arteriosclerosis and diabetic angiopathy is also an object of the present invention.

Angiotensin-converting enzyme is responsible for the cleavage of the circulatory-inactive angiotensin I to angiotensin II. The main activities of angiotensin II are known. Angiotensin II is a potent constrictor of smooth musculature, especially of vascular musculature. It stimulates the liberation of noradrenalin and inhibits its re-uptake in nerve endings, whereby it is additionally vasoconstrictive. It also influences prostaglandin liberation in such a manner that it is also constrictive. However, angiotensin II also promotes the new growth of blood vessels (angiogenesis ) . The use of ACE inhibitors as antihypertensives, namely by lowering the plasma level of angiotensin II and decreasing the total vascular resistance which follows therefrom, is based on the three first-mentioned main activities.6 Suitable ACE inhibitors for the purpose of the present invention are alacepril. benazepril, captopril. cilazapril. delapril. enalapril. enalaprilat, fosinopril. lisinopril. perindopril, quinapril, ramipril. spirapril, zofenopril and MC 838 [calcium salt of (R-(R.S) )-l-(3-( (2-- ( ( cyc 1ohexy1carbon 1 ) amino )-l-oxopropy1 ) thio)-2-methyl-l--oxopropyl)-L-proline] as well as analogues of these compounds which are described in European Patent Publications EPA 7.477. 12.401. 50.800. 51.391. 53.902. 65.301, 72.352. 94.095. 172.552. 211.220 and 271.795. US Patent Specifications 4.105.776 and 4.316.906. British Patent Specification 2.102.412 as well as Tetrahedron Letters. 23. 1677-1680 (1982). Preferred ACE inhibitors are the compounds referred to as being preferred in the named publications. The compounds specifically named above are especially preferred ACE inhibitors. Cilazapril is the most preferred ACE inhibitor.

For the prevention of trauma-induced neointima formation the ACE inhibitors, particularly cilazapril. are administered systemically. preferably enterally, particularly orally. The dosage varies according to the requirements of the individual patient as determined by 6 Journal of Clinical Investigation 79. 1-6 (1987) the attending physician. For the particularly preferred cilazapril a daily dosage of about 0.5 to 10 rag. preferably 2.5 or 5 mg. orally per day should in general be used. The dosage of 2.5 or 5 mg per day is that which corresponds to the therapeutically preferred established dosage for the treatment of high blood pressure with cilazapril. For the prevention of a restenosis after angioplasty the ACE inhibitors should preferably be administered before the intervention and thereafter until the risk of a restenosis can be disregarded, i.e. about one year. The other ACE inhibitors can be administered in conformity with the respective dosage regimen individually determined by the attending physician.

In this connection, it should also be pointed out that, because of the possibility of administering the ACE inhibitors orally, a duration of treatment is not limited in time, which is essential for the use in accordance with the invention.

As forms of administration there come into consideration the solid or liquid dosage forms which are usual for systemic administration, e.g. suppositories or as solid oral dosage forms capsules, tablets, coated tablets, dragees. pills, powders, granulates and the like, as liquid oral dosage forms solutions, syrups, suspensions, elixirs and the like and as parenteral dosage forms infusion or injection solutions which can be injected intravenously or intramuscularly.

In the scope of the present invention the ACE inhibitors, preferably cilazapril, can be incorporated in the enteral or oral dosage forms in any amount which is suitable for the administration. It is. however, preferred to manufacture preparations which contain per dosage unit the active ingredient in an amount of about 0.5-10 mg. preferably of about 2.5 or 5 mg. The manufacture of capsules and coated tablets is particularly preferred.

The manufacture of the aforementioned dosage forms can be effected in the usual manner, e.g. on the basis of the following Example for cilazapril.

Example 1 Tablets containing 0.5 mg of cilazapril Composition mq/tablet 1. Cilazapril (monohydrate) 0.522 (corr. to 0.5 mg of base) 2. Powd. lactose 82.028 3. Maize starch 39.000 4. Hydroxypropylmethylcellulose 5.200 5. Talc 1.950 6. Sodium stearyl fumarate 1.300 Weight per tablet nucleus 130.000 Coating composition: mg/coated tablet 7. Hydroxypropylmethylcellulose 1.50 8. Talc 0.75 9. Titanium dioxide 0.75 3.00 Total per coated tablet 133.00 mg The active ingredient is in succession homogeneously mixed with a mixture of lactose and maize starch, sieved and moistened with an aqueous hydroxypropylmethylcellulose solution, granulated and dried. Talc and sodium stearyl fumarate are admixed with the dried granulate and tablets of suitable size are manufactured from the ready-to-press mixture. The tablet nuclei are coated with an aqueous suspension of components 7-9 according to a suitable coating process.

Example 2 Coated tablets containing 10 mg of cilapril Composition mg/tablet 1. Cilazapril (raonohydrate) 10.44 (corr. to of base) 2. Powd. lactose 243.56 3. Maize starch 120.00 4. Hydroxypropylmethylcellulose 16.00 5. Talc 6.00 6. Sodium stearyl fumarate 4.00 Weight per tablet nucleus 400.000 Coating composition mq/coated tablet 7. Hydroxypropylmethylcellulose 5.00 8. Talc 2.50 9. Titanium dioxide 0.50 10. Red iron oxide 2.00 Total weight per coated tablet 410.00 mg The cilazapril active ingredient is homogeneously mixed with components 2-4. moistened with an aqueous solution of 4. granulated and dried. The dried granulate is homogeneously mixed with talc and sodium stearyl fumarate and pressed to tablet nuclei of suitable size. The tablet nuclei are coated with an aqueous suspension of components 7-10 according to a suitable coating process.

Example 3 Hard gelatine capsules containing 5 mg of cilazapril Composition mq/capsule Cilazapril (monohydrate) 5.22 (corr. to 5.0 mg of base) Powd. lactose 93.94 Cryst. lactose 110.00 Starch STA-RX 1500 48.00 Talc 2¾.00 Magnesium stearate 0.84 Weight per capsule filling 280.00 mg The cilazapril active ingredient is in succession homogeneously mixed with powd. lactose and sieved (I). Components 3-5 are homogeneously mixed and sieved (II). Mixtures I and II are then mixed and the ready-to-fill powder mixture is manufactured with the sieved magnesium stearate by means of a further mixing process. This final mixture is filled into hard gelatine capsules of suitable size .

The therapeutic activity of cilazapril in the case of vascular damage can be concluded from the following experiment. The experiment is described in such a manner that any person having the required knowledge and equipment can perform it. The scope of the use of the invention is not intended to be limited in any manner by the choice of the experiment carried out.

An artery is damaged from inside using a balloon catheter which is pushed through the vascular lumen (ballooning). By so doing, the innermost cell layer. the endothelium, is removed and the muscle cells of the media are slightly damaged. The muscle cells are thereby stimulated to proliferate and migrate into the intima. New 1 7 tissue, the neointima. results. ' 14 days after the ballooning the artery is fixed for morphometric studies. The extent of the neointima formation is subsequently measured on cross-sections through the artery with the aid of morphometric methods.

Male rats, strain: RORO (average weight 399 ± 6 g; 4-5 months old; Institute for Biological-Medical Research. Fullinsdorf) were used. The animals were randomized to either a control group or a treatment group. 11 animals were used as the control animals and 11 animals were used as treated animals.

The animals of the treatment group received for a period of 20 days cilazapril admixed with the feed such that the daily cilazapril intake amounted to an average of 10 mg/kg. This was a dosage which lowered the systolic blood pressure by about 25%. The control animals received the same laboratory feed without the additive. The ballooning of the common carotid artery was carried out 6 days after the first dose of cilazapril. The animals were narcotized using ether inhalation and subcutaneous administration of 200 mg/kg of sodium hexobarbital . The distal left common carotid artery and the bifurcation region of the external carotid and internal carotid were exposed. The FOGARTY catheter (12-060-2F. Edwards Laboratories. Santa Anna. CA, USA) was introduced through the external carotid artery into the common carotid artery up to the aortic arch, the balloon was filled with water (filling volume about 0.01-0.015 ml) and withdrawn against a slight resistance. This procedure was repeated twice. The Laboratory Investigation 49.. 327-333 (1983) Pathologia et Microbiologia 29.. 393-405 (1966) external carotid artery was ligated and the wound was stitched. The operators had no knowledge whether treated or untreated animals were involved. 14 days after the ballooning the rats were anaesthetized with ether and the carotids were fixed by perfusion with fixative (2.5% glutaraldehyde in 0.1M phosphate buffer. pH 7.4). For this purpose, a probe was passed through the left ventricle of the heart into the ascending aorta (inflow) and a second probe was pushed through the right ventricle into the auricle (outflow). Next, the vascular system was rinsed with 10 ml of PBS ("jDhosphate buffered saline"; buffered isotonic NaCl solution) and then fixed for a period of 15 min with fixative at a pressure of 90 mm mercury column.

Subsequently, not only the left (ballooned) but also the right (non-ballooned) carotid artery (control) were dissected out, freed from tissue and placed in 2.5% glutaraldehyde in 0.1M cacodylate buffer for further fixation. Each carotid artery was divided into five vascular segments from the distal to the proximal ends, drained and embedded in EPON 812 (registered mark of Shell A.G.). The middle segment was used for the morphological investigations.

Semi-thin cross-sections (1 μπι thick) were stained with toluidine blue and basic fuchsin. The following parameters ((l)-(5)) were measured using the DIASYS (Datalab. Heinz Meyer. CH-3367 Thorigen) morphometry system: 2 (1) The cross-sectional area of the neointima in μπι 2 (2) The cross-sectional area of the media in μπ» 2 (3) The cross-sectional area of the lumen in um (4) The length of the lamina elastica interna in the cross-section in um (5) The length of the lamina elastica interna covered with neointima in rn.

The following parameters were calculated from these measurements : (6) The average thickness of the neointima in um calculated as a circular ring from the cross-sectional area of the neointima. For this purpose, the neointima cross-section was transformed into a circular ring, the external limit of which formed the lamina elastica interna. (7) The cross-sectional area of the neointima to the cross-sectional area of the media in percent (normalized neointima area). (8) The percentage of the lamina elastica interna covered with neointima.

The essential morphological characteristics of the neointima in the ballooned carotid artery of untreated animals and cilazapril-treated animals are shown in the following Table. In detail, the following results were obtained : 2 The cross-sectional areas (um ; mean value ± standard deviation) of the neointima (parameter (1)) were 3 3 . 109 x 10 ± 51 x 10 in the case of the control 3 3 animals and 20 x 10 ± 18 x 10 in the case of the cilazapril-treated animals, which corresponds to an inhibition of 82%. 2 The cross-sectional areas (parameter (3); in m ) 3 3 of the liimen were 324 x 10 ± 91 x 10 in the case 3 3 . of the control animals and 468 x 10 ± 114 x 10 in the case of the cilazapr il-treated animals. Therefore, after treatment with cilazapril a substantially larger lumen area is available for the bloodflow.

The average thicknesses of the neointima (parameter (6); in μπι) amounted to 50 ± 25 and, respectively, 8 ± 7 for control animals and cilazapr il-treated animals, which corresponds to an inhibition of 84%.

The ratio of the cross-sectional area of the neointima to the cross-sectional area of the media (parameter (7)) amounted to 101 ± 43% for the controls and 23 ± 21% for the treated animals.

The lamina elastica interna of untreated, ballooned animals were covered to 93 ± 15% with neointima (parameter (8)). This covering was only 35 ± 29% in the case of animals treated with cilazapril.

The inhibiting activity of cilazapril on the neointima formation was statistically of high significance in the case of all parameters. The neointima formation was completely inhibited in the case of 3 of 11 animals. In all non-ballooned arteries (right carotid artery) no vascular changes were determined.

It is clearly shown by this that cilazapril suppresses the neointima formation produced by arterial damage and its consequences.

Untreated Animals treated animals with cilazapril (n = 11) (n = 11) Cross-section area 109xl03 ± 51x10 20xl03 ± 18xl03*** of the neointima (ym2) Cross-section area 324xl03 ± 91xl03 468xl03 ± 114xl03** of the lumen (μπι2) Average thickness of 50 ± 25 8 ± 7 the neointima (ym) Ratio of cross- 101 ± 43 23 ± 21 -section area of the neointima to cross- -section area of the media (%) Percentage of lamina 93 ± 15 35 ± 29 *** elastica interna covered with neointima (%) Meaning of the symbols: n: number of experimental animals; ***: 2p < 0.001 (t-Test) **: 2p < 0.01 (t-Test) Chronic high blood pressure leads to hypertrophy of the media in the large, muscular arteries. Successful treatment of high blood pressure with ACE inhibitors, as well to a lesser extent also with β-blockers and other existing therapeutics such as vasodilators, leads to a g reduction of the hypertrophy.

The novel use of ACE inhibitors described herein differs from that which leads to the reduction of hypertrophy in that here the formation of neointima is inhibited. It can be shown not only in the case of Hypertension 9. 178-187 (1987) hypertonics, but also in the case of norraotonics . when the processes described above occur in the vascular wall.

The current most investigated vascular damage occurs in the case of percutaneous, transluminal coronary angioplasty (PTCA) . Here, a stenosed or closed blood vessel is rendered patent by inflating a balloon catheter.

(This procedure closely resembles the ballooning described above). A problem which frequently occurs is the so-called restenosis, i.e. a re-closing. For example, it is known that in the case of coronary blood vessels a restenosis of 3 about 30% occurs within 6 months. Anatomical studies have shown that re-stenosis or -closure takes place at the site of the damage.

Another clinical application is to be seen in the case of artery-vein transplants. Restenosis occurs, for example, in the case of so-called bypass operations, where a vein or artery transplant replaces arteries, for example coronary blood vessels or carotids. A closure (primarily at the point of joining) can occur through the proliferation of smooth muscle cells.

Finally, migration and proliferation of smooth muscle cells play an important role in a whole series of disorders. Here there are to be mentioned especially 2 arteriosclerosis and diabetic angiopathy.

The New England Journal of Medicine, 318 1734-1737 (1988) ' The New England Journal of Medicine, 314. 488-500 (1986)

Claims (5)

- 17 - 91572/3 CLAIMS:

1. The use of ACE inhibitors for the manufacture of medicaments for the prevention of the proliferation of smooth muscle cells in the intima and/or the media, or of the migration of smooth muscle cells from the media into the intima, or of the formation of extracellular matrix, or for the treatment and prevention of neointima formation, all of these conditions appearing after vascular damage substantially as described in the specification.

2. The use according to claim 1 wherein the ACE inhibitors are alacepril, bena'zepr J.1', captopril. cilazapril. delapril. enalapril. enalaprilat, fosinopril. lisinopril,' perindopril, quinapril, ramipril sp-irapril, zofenopril and MC 838. preferably cilazapril.

3. A pharmaceutical composition in dosage unit form suitable for oral or parenteral administration for the prevention of the proliferation of; smooth muscle cells in the intima and/or the media, or of the migration of smooth muscle cells from the media into the intima, or of the formation of extracellular matrix, or for the treatment and prevention of neointima formation, all of these conditions appearing after vascular damage, particularly that caused physically, chemically or surgically, which composition comprises as active ingredient an ACE inhibitor, particularly alacepril. benazepril, captopril. cilazapril. delapril, enalapril. enalaprilat. fosinopril, lisinopril, perindopril, quinapril, ramipril. spirapril, zofenopril. and MC 838, preferably cilazapril, in an amount effective to prevent the proliferation of smooth muscle cells in the intima and/or the media, or the migration of smooth muscle cells from the media into the intima. or the 91572/3 formation of extracellular matrix, or to treat and/or prevent neointima formation, all of these conditions appearing after vascular damage, pa icularly- that caused physically, chemically or surgically.

4. A pharmaceutical composition in dosage unit form suitable for oral or parenteral administration for the prevention of arterial restenosis- after angioplasty, or of vascular wall thickening in arteries and veins after vascular surgery, or for the prophylaxis of arteriosclerosis and diabetic angiopathy, which composition comprises as active ingredient an ACE inhibitor, particularly alacepril. benazepril, captopril, cilazapril. delapril. enalapril. enalaprilat, fosinopril, lisinopril, perindopril, quinapril, raraipril, spirapril. zofenopril and MC 838, preferably cilazapril. in an amount effective to prevent arterial restenosis after angioplasty, or vascular wall thickening in arteries and veins after vascular surgery, or artriosclerosis and diabetic angiopathy. ■ "

5. A coramercial package containing as an active pharmaceutical ingredient an ACE inhibitor, particularly alacepril, benazepril, captopril. cilazapril, delapril. enalapril, enalaprilat. fosinopril. lisinopril. perindopril. quinapril, ramipril, spirapril, zofenopril and MC 838, preferably cilazapril. together with instructions for the use thereof as claimed in claim. ' 1. For the Applicants DR. REI HOLD COHN AND PARTNERS