WO2005082845A1

WO2005082845A1 - Novel therapies with somatostatin receptor agonists

Info

Publication number: WO2005082845A1
Application number: PCT/FI2005/000124
Authority: WO
Inventors: Jussi Tomperi; Mia Engström; Siegfried Wurster
Original assignee: Oy Juvantia Pharma Ltd
Priority date: 2004-02-27
Filing date: 2005-02-25
Publication date: 2005-09-09

Abstract

Use of an SSTR4 agonist for the manufacture of a pharmaceutical preparation useful in treating wounds or promoting wound healing or tissue repair in a mammal.

Description

NOVEL THERAPIES WITH SOMATOSTATIN RECEPTOR AGONISTS

FIELD OF THE INVENTION The invention relates to the use of agents causing the stimulation of the somatostatin receptor subtype 4 for the purpose of treating wounds and/or promoting wound healing and tissue repair.

BACKGROUND OF THE INVENTION The publications and other materials used herein to illuminate the background of the invention, and in particular, cases to provide additional details regarding the practice, are incorporated by reference. Somatostatin, also known as somatotropin release-inhibiting factor (SRIF), is a widely distributed peptide occurring in two forms, SRIF-14 and SRIF-28. SRIF has multiple functions, including regulation of neurotransmission in the brain, as well as modulation of secretion of growth hormone, insulin, glucagon, pancreatic enzymes and gastric acid. In addition to playing an important regulatory role in neurotransmission and secretion, the peptide may control cell proliferation in normal and tumorous tissues (1 ,2). Somatostatin and more stable peptide analogs thereof have been shown to suppress the growth of various cancer cells, including somatostatin receptor expressing neuroendocrine tumors, thus indicating that somatostatin possess direct anti-proliferative effects (3,4). Indirectly, SRIF exerts anti-proliferative effects by inhibiting the secretion of growth factors and hormones (5). During the past two decades several in vitro, in vivo and clinical studies have been done with SRIF or more stable analogs of it, because of the growth inhibitory effects on many synthetic and secretory processes. For example, somatostatin receptor subtype 2 agonists in particular have been suggested to be effective inhibitors of angiogenesis (6). EP 0657174 describes somatostatin or a somatostatin agonist for the inhibition of bile duct epithelium proliferation; WO 93/08866 discloses somatostatin analogues capable of reducing smooth muscle cell proliferation. Furthermore, EP 0175644 discloses somatostatin analogues effective in the treatment of diseases involving morbid proliferation or keratinisation of epidermal cells. The analogues could thus be useful in the treatment of psoriaris. WO 00/12111 described a method treating endothelial-cell- mediated proliferative diseases such as intimal hyperplasia or an angiogenic disease with SSTR1 or SSTR4 selective agonists. The few existing teachings connecting somatostatin and proliferation (or growth promotion) focus on somatostatin antagonists (WO 98/24807), means to reduce somatostatin levels (WO 99/66950) or ways to inhibit somatostatin actions (US 6,468,974). In summary, the documented effects of SSTR agonists on growth are primarily inhibitory; growth-promoting effects of SSTR agonists have been described only in a limited number of scientific reports (7-12). The biological responses of SRIF are mediated via high affinity G protein-coupled receptors, of which five different subtypes (SSTR1-5) have been cloned and characterized in humans (13,14). The design and synthesis of subtype selective ligands would aid in the determination of the physiological functions for the individual subtypes, and thus the development of novel clinical applications. However, due to the scarcity of completely subtype selective ligands, there is only limited information on the identity of the receptor subtypes mediating for instance the effects of SRIF on cell proliferation. The at times contrasting nature of cell growth responses observed upon application of SRIF to cells expressing multiple SSTRs may be caused by the simultaneous activation of several subtypes with mutually opposing effects. Lauder et al. (1997J report that SRIF-induced anti- proliferative effects in rat aortic vascular smooth muscle cells are mediated via the activation of receptors which are similar to human SSTR5 (15). In vitro, it has also been reported that the activation of recombinant mouse SSTR2 or SSTR5 inhibits serum-induced proliferation (16), whereas the stimulation of the human SSTR4 can induce proliferation in the absence of other mitogenic agents (10, 12). A significant depletion of neuropeptides, one of these being SRIF, have been demonstrated in the wound region, suggesting that these peptides may play an important role in the healing process (17). There is also evidence for the participation of SRIF in the pathophysiology of atopic dermatitis and urticaria pigmentosa (18,19). Since SRIF has been described as an anti-angiogenetic agent and angiogenesis is required for normal tissue repair, one could speculate that SRIF receptor antagonists might be useful in the healing of wounded tissues. However, it was now surprisingly found that selective somatostatin receptor subtype 4 agonists promote both the rate and the extent of wound healing in vivo.

SUMMARY OF THE INVENTION The present invention relates to the use of somatostatin receptor subtype 4 (SSTR4) agonists in wound healing and tissue repair. These compounds form the basis of compositions useful for promoting wound healing or tissue repair in a mammal, comprising of administering to said mammal at least one SSTR4 agonist in a therapeutically effective amount.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows forskolin-stimulated cAMP accumulation as a function of the concentration of SRIF-14 and compound A, an SSTR4 agonist. The data was normalized against the forskolin-induced cAMP accumulation in the absence of test compounds which was set as 100 %. Figure 2 shows the effects of compound A (SSTR4 agonist) and vehicle on wound closure rate and percentage. Figure 3 shows the effect of compound A on wound closure half time (CT₅₀). Figure 4 shows the effects of compounds A and B (another SSTR4 agonist) on wound closure (%) after 10 days of treatment.

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for treating wounds and promoting wound healing or tissue repair using agents, which cause stimulation of the somatostatin receptor subtype 4. It was surprisingly found that SSTR4 agonists significantly promoted wound closure (%) and reduced half closure time (CT₅₀) in vivo. DEFINITIONS The term "treatment" shall be understood to include the complete curing of a disease or condition, as well as the amelioration or alleviation of the said disease or condition. The term "mammal" shall refer to a human or an animal subject. The term "SSTR4 agonist" shall be understood as a substance or drug that has affinity for and stimulates the SSTR4. The wording "selective SSTR4 agonist" shall be understood to refer to an agonist with a binding affinity for the somatostatin receptor subtype 4 (e.g. in form of its Ki value), which is at least 10 times better than any of the affinities for the somatostatin receptor subtypes 1 , 2, 3 or 5. The term "tissue repair" shall be understood to include all healing processes through which the body replaces lost or dead tissue with new tissue that is identical or similar in structure and function. In addition, the term "tissue repair" shall also refer to healing processes, in which the body replaces lost or dead tissue with connective tissue. In other words, the term

"tissue repair" shall refer to regenerative tissue healing responses as well as to tissue healing responses in which lost or dead tissue is replaced by fibrous connective tissue. The method includes a step of administering a therapeutically effective amount of an SSTR4 agonist (e.g. an SSTR4 selective agonist) to a mammal in need of the treatment. A therapeutically effective amount depends upon the condition being treated, the route of administration chosen and the specific activity of the compound used and ultimately will be decided by the attending physician or veterinarian. Depending on the disease, condition or stage of those, the duration of administration of the somatostatin subtype 4 agonist to the patient may, for example, last until the disease or condition has subsided or, if necessary, the somatostatin agonist may be administered for the lifetime of the patient. The SSTR4 agonists within the scope of the invention may be formulated in a conventional manner using one or more pharmaceutically acceptable carrier or excipient to produce pharmaceutical compositions for the treatment of the diseases or disorders disclosed. Formulations may for instance enable topical, oral, buccal, intranasal, parenteral (e.g. intravenous, intramuscular or subcutaneous) or rectal administration or administration by inhalation or insufflation. Furthermore, the SSTR4 agonists belonging to the scope of the invention may also be formulated for slow release using for example oils or biodegradable matrices. For topical administration, suitable compositions include, but are not limited to, liquid, semi-solid or solid compositions for direct application to the wound or target tissue. Furthermore, the composition may be applied to the surface of, or be incorporated into a solid tissue or wound contacting layer, such as a wound dressing, sheet, patch or a film. The layer may also be made of biocompatible, self-adhesive material or material which is biodegradable. More preferably, the composition is a fluid, a gel or a cream comprising at least one SSTR4 agonist optionally together with conventional pharmaceutical excipients for topical application to the wound or target tissue. Suitable carriers include, but are not limited to, hydrogels containing cellulose derivatives, such as hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and mixtures thereof; and hydrogels containing polyacrylic acid. Furthermore, suitable carriers include oil-based emulsions, pastes, gels, creams and ointments used for topical pharmaceutical preparations. The above carriers may include thickeners (such as alginate), preservatives (such as benzyl alcohol), buffers for pH control (such as disodium hydrogen phosphate together with sodium dihydrogen phosphate), agents to adjust osmolarity (such as sodium chloride) and stabilisers (such as EDTA). Besides the conventional compositions, the composition may be a slow release composition, where at least one SSTR4 agonist is dispersed in a slow release solid or semi-solid matrix, such as a matrix of alginate, collagen, or a synthetic biocompatible polymer. For oral administration, forms of suitable compositions include but are not limited to tablets, chewable tablets and capsules. These may be prepared by conventional means with pharmaceutically acceptable excipients, such as binding agents (e.g. pregelatinized maize starch), disintegrants (e.g. potato starch), fillers (e.g. lactose) or lubricants (e.g. magnesium stearate). Tablets may be coated by methods well known in the art. For oral administration, possible liquid preparations include but are not limited to solutions, syrups or suspensions, or they may exist as dry powder for constitution with water or another suitable vehicle prior to use. These liquid preparations may be prepared by conventional means with pharmaceutically acceptable agents, such as suspending agents, non- aqueous vehicles, preservatives and emulsifiers. A possible dose of the therapeutics within the scope of the invention for oral, parenteral, buccal or topical dose to the adult human could for instance be between 0.1 and 500 mg of the active compound per unit dose, which may be administered, for instance, 1 to 4 times a day. It is well recognized that the precise dose, the route of administration and the dosing interval can be determined by those skilled in the art. It is also well recognized that these variables depend on multiple factors including, but not restricted to, the activity of the therapeutic compound, the formulation thereof, the pharmacokinetic properties (such as absorption, distribution, metabolism and excretion) of the therapeutic compound, the nature and location of the target tissue or organ and the issues connected to the state of a disease or disorder in a patient in need of treatment. Additionally, when the SSTR4 agonists within the scope of the invention are administered with additional pharmaceutically active ingredients, one or more pharmaceutical compositions may be used for the delivery of all the agents, which may be administered together, or at different times, as determined by those skilled in the art. The wound can be an acute wound or a chronic wound. As non- limiting examples of acute wounds can be mentioned abrasions, scrapes, avulsions, contusions, bruises, crushes, cuts, lacerations, velocity wounds, punctures or burns. Non-limiting examples of abrasions or scrapes include rope burns, skinned knees and the like. Non-limiting examples of avulsions include loss of permanent tooth, ear lobe, finger and the like. Non-limiting examples of contusions or bruises include subcutaneous bruises, intramuscular bruises, periosteal bruises and the like. Non-limiting examples of crushes include smashed fingers, toes and the like. Non-limiting examples of cuts and lacerations include knife cuts, paper cuts, surgical incisions and the like. Non-limiting examples of velocity wounds include gunshot wounds, arrow wounds, wounds occurred in traffic accidents, and the like. Non-limiting examples of punctures include deep narrow wounds caused for instance by nails, knives, needles, broken glass, and the like.

Non-limiting examples of burns include first-degree, second-degree and third degree burns, which may be caused for instance by heat, radiation, friction, the sun, electricity or chemicals. As non-limiting examples of chronic wounds can be mentioned any type of ulcer and sore. Non-limiting examples of ulcers and sores include venous ulcers, arterial ulcers, stasis ulcers, decubitus ulcers, pressure sores, leg ulcers, venous leg ulcers, venous stasis ulcers, diabetic ulcers, such as diabetic leg ulcers, peptic ulcers, gastric ulcers, mouth ulcers, necrotic ulcer, ulcers of unknown etiology, any ulcer arising from an inflammatory reaction and the like. Yet another aspect of the invention is the treatment of ischemic wounds or tissues, for instance by inducing angiogenesis. Yet another aspect of the invention is the promotion of wound healing or tissue repair. The promotion of wound healing or tissue repair may be the result of enhanced or accelerated re-epithelialization or re-endothelialization of a tissue. The promotion of wound healing or tissue repair may be caused by stimulating the influx of fibroblasts, vascular endothelial cells or epithelial cells into a wound, which comprises contacting the fibroblasts, vascular endothelial cells, epithelial cells, or a combination thereof with an agent which causes the stimulation of SSTR4 on any of the cells. In addition, the promotion of wound healing or tissue repair may be caused by enhancing the proliferation of fibroblasts, vascular endothelial cells or epithelial cells in a wound, which comprises contacting the fibroblasts, vascular endothelial cells, epithelial cells, or a combination thereof with an agent which causes the stimulation of SSTR4 on any of the cells. Yet another aspect of the invention is the treatment of wounds or injuries occurring in the epidermis and/or dermis. A preferred embodiment of the present invention is the treatment of acute wounds, and even more preferably the treatment of abrasions, cuts, lacerations, punctures and burns. Another preferred embodiment of the present invention is the treatment of chronic wounds, and even more preferably the treatment of arterial ulcers, peptic and gastric ulcers and leg ulcers of diabetic and non- diabetic origin. Another preferred embodiment of the present invention is the treatment of ischaemic wounds or tissues. Another preferred embodiment of the present invention is the treatment of epidermic wounds. In one aspect the invention also provides a method for treating a wound in a subject, comprising administering to the subject at least one agent which causes the stimulation of the SSTR4 in combination with an agent selected from the group consisting of an antibacterial agent, an antiviral agent, an antifungal agent, an antiparasitic agent, an antiinflammatory agent, an analgesic agent, an antipruritic agent, or a combination thereof. Yet another aspect of the invention is a method for treating a wound or damaged tissue by administering of combination medication consisting of at least one SSTR4 agonist together with another medication promoting wound healing or tissue repair in a patient. An especially preferred agents or medications together with the SSTR4 agonist are growth factors, such as hEGF (human epidermal growth factor), VEGF (vascular endothelial growth factor), bFGF (basic fibroblast growth factor), PDGF (platelet-derived growth factor), IGF (insuline-like growth factor) and TNF (tumor necrosis factor), growth hormones and oxygen therapy. According to a preferred embodiment, the SSTR4 agonist is a selective SSTR4 agonist. More preferably, its affinity (e.g. in form of its Kj value) for the SSTR4 should be at least 10 times better than that for any of the other somatostatin receptor subtypes 1 , 2, 3 or 5. Even more preferably, its affinity for the SSTR4 should be at least 100 times better than that for any of the other somatostatin receptor subtypes 1 , 2, 3 or 5. In another preferred embodiment, the SSTR4 agonist may be applied topically to the surface of injured tissue for the treatment of acute and chronic wounds. In addition, intrapehtoneal injured tissues, such as it may result from invasive surgery, may be treated with a composition in accordance with the present invention to accelerate the healing process. For example, following the surgical removal of a colon section or other tissue, the surgical plane may be coated with a solution of active agent prior to closing the surgical site in order to accelerate internal capillary perfusion and healing. In addition, the rate of localized healing may be increased by the subdermal administration of active agent by injection or otherwise. Especially preferred SSTR4 agonists are the compounds (1'S, 2S)-A/-(1'-carbamoyl-2'-phenylethyl)-5-guanidino-2-(4"-methyl-1"-naphtha- lenesulfonylamino)pentanamide (in the following compound A) and (1 'S, 2S)-4-amino-Λ/-(1 '-carbamoyl-2'-phenylethyl)-2-(4"-methyl-1 "-naphtha- lenesulfonylamino)butanamide (in the following compound B). These compounds have been disclosed in the Finnish patent applications FI20031454 and FI20031455. The invention will be illuminated by the following non-restrictive Experimental Section.

EXPERIMENTAL SECTION

Cell Culture and Transfections Chinese hamster ovary (CHO) cells (K1 strain) were cultured in Ham's F12 medium (Nutrient Mixture Ham's F12; Invitrogen, Glasgow, UK) containing 10 % fetal calf serum (FCS). The cDNA encoding the human SSTR1 (hSSTRI) or human SSTR4 (hSSTR4) was subcloned from a construct in pBluescript (Stratagene, San Diego, CA), into a bicistronic mammalian expression construct (Clontech, Palo Alto, CA) with an amino- terminal hemagglutinin tag (Clontech, Palo Alto, CA) (and EF1 promoter (Invitrogen, Groningen, Netherlands) in hSSTR4 cloning) using FuGENE™ 6 Transfection Reagent (Roche Diagnostics Corporation, Indianapolis, IN). Stable transfectants were selected in Ham's F12 containing G418 at 500 μg/ml. After selection, transfected CHO-hSSTR4 cells were sorted and the highest-expressing cells collected by fluorescence-activated cell sorting (Flow Cytometry Core Facility, Turku, Finland). Hereafter, both the sorted CHO-hSSTR4 and the unsorted CHO-hSSTR1 cells were cloned by dilution- plating. The highest expressing clone was identified in SRIF binding assays using (¹²⁵l-Tyr)-[Leu⁸,DTrp²²]-somatostatin-28 (¹²⁵l-LTT-SRIF-28) (Anawa, Zurich, Switzerland; specific activity: 2000 Ci/mmol) as tracer. CHO cells expressing the human SSTR2 (hSSTR2), human SSTR3 (hSSTR3) and human SSTR5 (hSSTRδ) were obtained from Prof. Kjell Oberg (Uppsala University Hospital, Sweden). The recombinant CHO cells expressing the SSTR subtypes were grown in Ham's F12 medium supplemented with 5 % foetal bovine calf serum and 200-250 μg/ml G418. Membrane preparation Recombinant CHO cells expressing the human SSTR:s were harvested in phosphate-buffered saline, and frozen at -70°C. To prepare membranes, thawed cell pellets were homogenized under ice-cooling in a Potter Elvehjem homogeniser in 10 mM Tris-HCI, 0.1 mM EDTA, pH 7.5 at RT, supplemented with 320 mM sucrose. The nuclear pellet obtained by centrifugation of the homogenate at 1 000 g for 15 min at 4°C was discarded. From the supernatant, a membrane fraction was collected by centrifugation at 48 000 x g_max for 30 min at 4°C. The 48 000 x g pellet was re-suspended in 10 mM Tris-HCI, 0.1 mM EDTA, pH 7.5 at RT without sucrose and centrifuged again at 48 000 x gm_ax for 30 min. The supernatant was discarded and the washed membranes were resuspended in 10 mM Tris-HCI, 0.1 mM EDTA, pH 7.5 at RT and thereafter stored at -70°C. Binding affinity on human somatostatin receptor subtypes The affinity of SRIF-14 and compounds A and B for the five human somatostatin receptor subtypes (hSSTRI -5) was determined in competition binding assays with (¹²⁵l-Tyr)-[Leu⁸,DTrp²²]-somatostatin-28 (¹²⁵l-LTT-SRIF-28). The biological material for these experiments consisted of membranes from Chinese hamster ovary (CHO) cells stably transfected with one of the five human somatostatin receptor subtypes. Membranes (3- 20 μg of total protein per sample) and trace amount of ¹²⁵l-LTT-SRIF-28 were incubated in 10 mM Hepes, 1 mM EDTA, 5 mM MgCI₂, 5 mg/ml of BSA and 30 μg/ml bacitracin, pH 7.6 with six concentrations of the compounds. Each concentration was run in duplicate. Nonspecific binding was defined by 1 μM somatostatin- 14 (SRIF-14) and corresponded to 5-25 % of total binding. After 60 min at room temperature, incubations were terminated by rapid vacuum filtration through GF/B glass fiber filter mats (presoaked at 4°C in 200 ml of 10 mM Hepes, 1 mM EDTA, 5 mM MgCI₂, pH 7.6) and three 5 ml washes with ice-cold wash buffer (20 mM TRIS, 1 mM EDTA, 5 mM MgCI₂, pH 7.4). The filters were then dried, impregnated with scintillate and their radioactivity was measured by scintillation counting. The analysis of the experiments was carried out by nonlinear least square curve fitting. Affinity constants (K,) were calculated from the ICso-values according to the Cheng-Prusoffs equation (20). Experiments were repeated a minimum of three times. Adenylate Cyclase Activity CHO cells expressing hSSTR4 (2.5 x 10⁴ cells per well in 96-well plates) were cultured for 20 h at 37°C in Ham's F12 medium containing 5 % FCS and thereafter for 1 h in serum-free medium. Cells were further incubated for 10 min with 0.03 mM indomethacine, 0.03 mM rolipram, and 0.1 mM propranolol in a cell incubator, before the addition of various concentrations of agonists and/or 10 μM forskolin. After 30 min, incubations were terminated by removing the medium and adding 20 μl of Lysis Buffer (PerkinElmer™ Life Sciences, Wallac Oy, Turku, Finland) per well. Cyclic AMP (cAMP) was measured by using a 4003-0010 DELFIA^® cAMP kit as recommended by the manufacturer (PerkinElmer™ Life Sciences, Wallac Oy, Turku, Finland). In vivo wound healing assay A study group consisted of five ICR derived male mice (weight 24 ± 2 g) and for each control or treatment condition one study group was used. During the testing period, the animals were single-housed in cages. Under hexobarbital (90 mg/kg, IP, Sigma USA) anesthesia, the shoulder and back region of each animal was shaved. A sharp punch (ID 12 mm) was applied to remove the skin including panniculus carnosus and adherent tissues. The wound area, as traced onto clear plastic sheets on days 0, 2, 4, 6, 8 and 10, was measured by an Image Analyzer (Life Science Resources Vista). Test compounds (20 μg/mouse) and vehicle (1.5 % carboxymethyl cellulose in phosphate buffered saline, pH 7.4, Sigma USA) were administered topically immediately after the injury and then once daily for ten days. The closure of the wound (%) was measured and the wound half-closure time (CT₅₀) determined by regression analysis using Graph-Pad Prism (Graph Pad Software USA). Unpaired Student's t test was applied for the comparison between treated and vehicle groups. Differences were considered to be statistically significance at a p < 0.05 level.

Example 1

Compounds A and B are selective for hSSTR4 The affinity of SSTR ligands was tested in competition binding assays with ¹²⁵l-LTT-SRIF-28 and membranes from CHO-K1 cells expressing one of the five human somatostatin receptor subtypes (hSSTRI -

5). Using the protocol described above, the following test results were obtained: r_no_mmp_nnou _nnHα K, (h _/S_nS_MTRI ) K, (h _/S_nS_MTR2) K, (h _/S_nS_MTR3) K, (h _/S_nS_MTR4) K, (h _/S_nS_MTR5) compound A 73 ± 19 >10 000 >10 000 3.6 ± 0.7 >10 000 compound B 500 ± 150 >5 000 1 400 ± 100 1.2 ± 0.4 540 ± 80

SRIF-14 1.4 ± 0.2 0.62 ± 0.15 1.6 ± 0.2 4.1 ± 0.6 4.1 ± 0.4

The table shows that compound A binds to the hSSTR4 with a 20 times better affinity than to the hSSTRI , while it does not, at concentrations up to 10 μM, bind to the other hSSTRs. The SSTR4-selectivity of compound

B over each of the other hSSTRs is at least 400-fold. SRIF-14 was included as a control peptide in competition binding assays with ¹²⁵l-LTT-SRIF-28.

Example 2 Compounds A and B are agonists at the hSSTR4 as demonstrated here for compound A The functional activity of compound A was assessed as its ability to inhibit forskolin-stimulated cAMP production in CHO-K1 cells recombinantly expressing hSSTR4. The addition of 10 μM forskolin increased the basal rate of cAMP accumulation by about 10-fold in the

CHO-hSSTR4 cells. Fig 1. shows that both SRIF-14 and compound A inhibited forskolin-stimulated cAMP production by more than 90%. The EC50-values of SRIF-14 and compound A were 1.9 ± 0.9 nM and 0.067 ± 0.03 nM, respectively.

Example 3

Compounds A and B are active in wound healing Using the protocol described in above, SSTR4 agonists were shown to increase the rate of wound closure (Fig. 2 and 3) as well as the extent of wound closure (Fig. 2 and 4).

It will be appreciated that the methods of the present invention can be incorporated in the form of a variety of embodiments, only a few of which are disclosed herein. It will be apparent for the expert skilled in the field that other embodiments exist and do not depart from the spirit of the invention. Thus, the described embodiments are illustrative and should not be construed as restrictive.

REFERENCES 1. Lamberts, S. W. J., Krenning, E. P., and Reubi, J.-C. (1991). The role of somatostatin and its analogs in the diagnosis and treatment of tumors. Endocr Rev 12, 450-482. 2. Schally, A. V. (1988). Oncological applications of somatostatin analogues. Cancer Res 15, No. 48, 6977-6985. 3. Arnold, R. and Frank, M. (1996). Control of growth in neuroendocrine gastro-enteropancreatic tumours. Digestion 57, 69-71. 4. Pollak, M. N. and Schally, A. V. (1998). Mechanism of antineoplastic action of somatostatin analogs. Pro Soc Exp Biol Med 217, No. 2, 143- 152. 5. Lamberts, S. W., Oosterom, R., Neufeld, M., and del Pozo, E. (1985). The somatostatin analog SMS 201-995 induces long-acting inhibition of growth hormone secretion without rebound hypersecretion in acromegalic patients. J Clin Endocrinol Metab 60, No. 6, 1161-1165. 6. Woltering, E.A., Watson, J.C, Alperin-Lea, R.C., Sharma, C, Keenan, E., Kurozawa, D., and Barrie, R. (1997). Somatostatin analogs: angiogenesis inhibitors with novel mechanisms of action. Invest. New Drugs 15, 77.86. 7. Douziech, N., Calvo, E., Coulombe, Z., Muradia, G., Bastien, J., Aubin, R. A., Lajas, A., and Morisset, J. (1999). Inhibitory and stimulatory effects of somatostatin on two human pancreatic cancer cell lines: a primary role for tyrosine phosphatase SHP-1. Endocrinol 140, No. 2, 765-777. 8. Ishizuka, J., Beauchamp, R. D., Evers, B. M., Townsend, C. M., and Thompson, J. C. (1992). Unexpected growth-stimulatory effect of somatostatin analogue on cultured human pancreatic carcinoid cells. Biochem Biophys Res Commun 185, 577-581. 9. Kamiya, Y., Ohmura, E., Arai, M., Fujii, T., Hayakawa, F., Ito, J., Kawaguchi, M., Tsushima, T., and Sakuma, N. (1993). Effect of somatostatin and its analogue on proliferation of human epidermoid carcinoma cells in vitro. Biochem Biophys Res Commun 191 , No. 1 , 302-307.

10. Lauder, H., Sellers, L. A., Feniuk, W., and Humphrey, P. P. A. (1998). Somatostatin-induced regeneration of CHO-K1 cells expressing recombinant human sst4 receptors is mediated by activation of MEK. Br J Pharmacol 123, 126 (abstr.).

11. Ruiz-Torres, P., Lucio, F. J., Gonzalez-Rubio, M., Rodriguez-Puyol, M., and Rodriguez-Puyol, D. (1993). A dual effect of somatostatin on the proliferation of cultured rat mesangial cells. Biochem Biophys Res Commun 195, 1057-1062.

12. Sellers, L A., Feniuk, W., Humphrey, P. P. A., and Lauder, H. (1999). Activated G protein-coupled receptor induces tyrosine phosphorylation of STAT3 and agonist-selective serine phosphorylation via sustained stimulation of mitogen-activated protein kinase. J Biol Chem 273, No. 23, 16423-16430.

13. Patel, Y. C. (1999). Somatostatin and its receptor family. Front Neuroendocrinol 20, 157-198.

14. Reisine, T. and Bell, G. I. (1995). Molecular biology of somatostatin receptors. Endocr Rev 16, 427-442. 15. Lauder, H., Sellers, L.A., Fan, T.-P.D., Feniuk, W., and Humphrey, P.P.A. (1997). Somatostatin sst₅ inhibition of receptor mediated regeneration of rat aortic vascular smooth muscle cells. Br J Pharm 122, 663-670.

16. Buscail, L., Esteve, J.-P., Saint-Laurent, N., Bertrand, V., Reisine, T., O'Carroll, A.-M., Bell, G. I., Schally, A. V., Vaysse, N., and Susini, C. (1995). Inhibition of cell proliferation by the somatostatin analogue RC- 160 is mediated by somatostatin receptor subtypes SSTR2 and SSTR5 through different mechanisms. PNAS 92, 1580-1584.

17. Senapati, A., Anand, P., McGregor, G. P., Ghatei, M. A., Thompson, R. P., and Bloom, S. R. (1986). Depletion of neuropeptides during wound healing in rat skin. Neurosci Lett 71 , 101-105. 18. Johansson, O. (1985). Morphological characterization of the somatostatin-immunoreactive dendritic skin cells in urticaria pigmentosa patients by computerized image analysis. Scand J Immunol 21 , 431-439. 19. Pincelli, C, Fantini, F., Massimi, P., Girolomoni, G., Seidenari, S., and Giannetti, A. (1990). Neuropeptides in skin from patients with atopic dermatitis: an immunohistochemical study. Br J Dermatol 122 ,Nr. 6, 745-750. 20. Cheng, Y. and Prusoff, W.H. (1973). Relationship between the inhibition constant (KI) and the concentration of inhibitor which causes 50 per cent inhibition (/₅₀) of an enzymatic reaction. Biochem Pharmacol 22, 3099-3108.

Claims

CLAIMS 1. Use of at least one SSTR4 agonist for the manufacture of a pharmaceutical preparation useful in treating wounds or promoting wound healing or tissue repair in a mammal.

2. The use according to claim 1 , wherein the wound or tissue damage is acute, chronic or ischaemic in nature.

3. The use according to any of claims 1 to 2, wherein the wound or tissue damage is an abrasion, scrape, avulsion, contusion, bruise, crush, cut, laceration, velocity wound, puncture or a burn type of wound.

4. The use according to any of the claims 1 to 2, wherein the wound or tissue damage represents a venous ulcer, arterial ulcer, stasis ulcer, decubitus ulcer, pressure sore, leg ulcer, venous leg ulcer, venous stasis ulcer, diabetic ulcer, diabetic leg ulcer, peptic ulcer, gastric ulcer, mouth ulcer, necrotic ulcer, any ulcer arising from an inflammatory reaction, or an ulcer of unknown etiology.

5. The use according to claim 1 , wherein the administration of at least one SSTR4 agonist causes enhanced or accelerated re- epithelialization or re-endothelialization of a tissue.

6. The use according to claim 1 , wherein the wound or damaged tissue is located in the epidermis or dermis.

7. The use according to claim 1 , wherein at least one SSTR4 agonist is applied topically.

8. The use according to claim 1 , wherein at least one SSTR4 agonist is administered in conjunction with a wound dressing.

9. The use according to claim 1 , wherein the SSTR4 agonist is a selective SSTR4 agonist.

10. The use according to claim 1 , wherein the administration includes a pharmaceutical composition comprising of at least one SSTR4 agonist in a slow release composition.

11. The use according to claim 1 , wherein at least one SSTR4 agonist is administered in combination with another agent or medication useful for wound healing or tissue repair.

12. The use according to claim 11 , wherein at least one other agent is selected from the group consisting of an antibacterial agent, an antiviral agent, an antifungal agent, an antiparasitic agent, an antiinflammatory agent, an analgesic agent and an antipruritic agent.

13. The use according to claim 11 , wherein at least one other medication is selected from the group consisting of oxygen therapy, growth factors and growth hormones.

14. Use of (1'S, 2S)-Λ/-(1'-carbamoyl-2'-phenylethyl)-5-guanidino- 2-(4"-methyl-1"-naphthalenesulfonylamino)pentanamide and/or (VS, 2S)-4- amino-Λ-(1'-carbamoyl-2'-phenylethyl)-2-(4"-methyl-1"-naphthalenesulfonyl- amino)butanamide for the manufacture of a pharmaceutical preparation useful in treating wounds or promoting wound healing or tissue repair in a mammal.