WO2010015870A1

WO2010015870A1 - Use of dihydralazine for the treatment of diseases related to elevated semicarbazide sensitive amine-oxidase (ssao) activity

Info

Publication number: WO2010015870A1
Application number: PCT/HU2009/000073
Authority: WO
Inventors: Péter MÁTYUS; János Németh; Kálmán Magyar; Anikó SOMOGYI; Petra Dunkel; Gábor Márk SOMFAI; Balázs BALOGH; György TÚRÓS
Original assignee: Semmelweis Egyetem
Current assignee: Semmelweis Egyetem
Priority date: 2008-08-06
Filing date: 2009-08-05
Publication date: 2010-02-11
Anticipated expiration: 2011-02-06
Also published as: EP2326328B1; EP2326328A1; HUP0800498A2

Abstract

The present invention relates to the use of dihydralazine for the treatment of diseases related to elevated level of SSAO activity and its use for the manufacture of pharmaceutical compositions for the treatment of such diseases.

Description

Use Of Dihydralazine For The Treatment Of Diseases Related To Elevated Semicarbazide Sensitive

Amine-Oxidase (Ssao) Activity

Field of the invention

The present invention relates to the use of dihydralazine for the treatment of diseases related to elevated level of SSAO activity and its use for the manufacture of pharmaceutical compositions for the treatment of such diseases. Said diseases related to elevated SSAO activity include: acute or chronic inflammatory conditions and diseases related to elevated SSAO activity, connective tissue inflammatory conditions and diseases, rheumatoid arthritis, ankylosing spondylitis, lupus erythematosus, vasculitis, synovitis, gastrointestinal inflammatory conditions and diseases, ulcerative colitis, Crohn's disease, irritable bowel syndrome, central nervous system inflammatory conditions and diseases, Alzheimer's disease, multiple sclerosis, pulmonary inflammatory conditions and diseases, asthma, inflammatory skin conditions, psoriasis, contact dermatitis, atopic dermatitis, liver inflammatory conditions and diseases, inflammatory conditions and diseases of the eye (eyeball, accessory and protective structures of the eye, orbit), macular edema, diseases related to carbohydrate metabolism, diseases related to adipocyte differentiation or dysfunction, diseases related to smooth muscle cell dysfunction, atherosclerosis, obesity, vascular diseases, arteriosclerosis, Raynaud's disease. In a preferred embodiment of the invention, dihydralazine is used to decrease SSAO activity in such a dose, that does not lead to appreciable drop in blood pressure in the animal or human treated.

Background of the invention

Semicarbazide sensitive amine oxidase (SSAO) catalyzes the oxidative deamination of primary aliphatic and arylalkylamines, resulting in the formation of the corresponding aldehyde, with the concomitant production of H₂O₂ and NH₁. The physiological substrates of SSAO are aminoacetone and methylamine. SSAO differ from the other main group of amine oxidases including MAO-A and MAO-B with respect to cofactor, subcellular distribution, biological function, substrates and inhibitors. In the human genome, three SSAO genes have been identified, AOCl corresponding to diamine oxidase (DAO) (Chassande, O. et a!., J. Biδl. Chem., 1994, 269, 14484-14489), A0C2 coding for retina-specific SSAO (Imamura, Y. et a!., Genomics, 1997, 40, 277-

283; Imamura, Y. et al., Genomics, 1998, 51, 293-298; Zhang, Q. et al., Gene, 2003, 318, 45-53), and A0C3 for human placental amine oxidase/VAP-1 (Zhang, X. and McEntire, W.S.. Gene, 1996, 179, 279-286; Smith, D.J. et al., J. Exp. Med., 1998, 188, 17-27).

SSAO is involved in the metabolism of biogenic and xenobiotic amines. The human SSAO enzyme exists as a membrane-bound and as a soluble form in the plasma, its activity displaying a wide tissue distribution. The major sources of the enzyme are the endothelial cells, smooth muscle cells and adipocytes. Sequence identity of SSAO was reported with vascular adhesion protein- 1 (VAP-I), which has a role in the adhesion of lymphocytes, therefore in inflammation (Smith, DJ. et al., J. Exp. Med., 1998, 188, 17-27). Elevated SSAO levels or overexpression of the enzyme have been reported in various pathological conditions (e.g. congestive heart failure (Boomsma, F. et al., Cardiovasc. Res., 1997, 33, 387-391), end-stage renal disease (Kurkijarvi, R. et al., Eur. J. Immunol., 2001 , 31 , 2876-2884), inflammatory liver diseases (Kurkijarvi, R. et al., J. Immunol., 1998, 161 , 1549-1557), multiple sclerosis (Airas, L. et al., J. Neuroimmunol., 2006, 177, 132- 135), psoriasis (Madej, A. et al., J. Eur. Acad. Dermatol. Venerol., 2007, 21 , 72-78), Alzheimer's disease (del Mar Hernandez, M. et al., Neurosci. Lett., 2005, 384, 183- 187; Ferrer, I. et al., 2002, 321, 21-24) and myopathies (Olive, M. et al., Muscle Nerve, 2004, 29, 261-266)).

Elevated levels of SSAO activity have been observed in type I and type II diabetes, markedly in the presence of diabetic complications (Boomsma, F. et al., Biochim. Biophys. Acta, 2003, 1647, 48-54; Boomsma, F. et al., Clin. ScL, 1995, 88, 675-679; Garpenstrand, H. et al., Diabetic. Med., 1999, 16, 514-521 ; Meszaros, Z. et al., Metab. Clin. Exp., 1999, 48, 1 13-1 17; Boomsma, F. et al., Diabetoiogia, 1999, 42, 233-237; Salmi, M. et al., Am. J. Pathol., 2002, 161 , 2255-2262). Elevated SSAO activity has been reported in diabetic retinopathy, supporting the hypothesis that SSAO may be involved in the pathogenesis of this diabetic complication.

Thus, pharmacological inhibition of the SSAO enzyme may exert beneficial effects in various diseases. As a consequence of the elevated activity of the enzyme in diabetes, there is an increased formation of the cito- and/or angiotoxic enzyme products, that may contribute to the pathogenesis of diabetic complications. Since there is a high expression of SSAO in the endothel and the plasma, the SSAO-related citotoxic effects might be more significant in the highly vascularised tissues, such as for example in the eyes (Ekblom, J., Pharmacol. Res., 1998, 37, 87-92). The citotoxic enzyme products in case of the physiological substrates are formaldehyde, methylglioxal, NH₃ and H₂O₂, that may increase the deleterious effects of oxidative stress, moreover may lead to the formation of protein cross-links and advanced-glycation end-products (AGEs). The said processes have an important role also in the pathogenesis of diabetic complications. Thus, inhibitors of SSAO activity may be useful for the treatment of diabetic complications, particularly diabetic retinopathy and diabetic macular edema. Diabetic retinopathy and diabetic macular edema are severe complications of diabetes even in an epidemiological aspect. Diabetic retinopathy is the second leading cause of acquired blindness in adults. Currently, the primary treatment of diabetic retinopathy and macular edema is retinal laser photocoagulation therapy. However, this therapy is relatively time consuming besides leading to a beneficial outcome only in a moderate number of cases, mostly helping to reduce the progression of the disease. A routine treatment is pars plana vitrectomy, i.e. surgical clearing of the vitreous body. The surgical technique however is rather elaborate, costly and has certain risks. On the other hand, the currently available pharmacological therapies are not effective enough, they can lead only to a transient amelioration of the condition. Therefore, there is a great demand for novel pharmacological agents, that are more effective than the currently available therapies (Ciulla, A.T. et al., Diabetes Care, 2003, 26, 2653-2664). Of the potential pharmacological therapies of retinopathy, clinical trials have been conducted with AGE inhibitors and antioxidants (Soro-Paavonen, A., Curr. Med. Chem., 2006, 13, 1777- 1788). Retinal leukostasis, capillary occlusion and on the other hand, chronic, low-grade subclinical inflammation were suggested to have central and causal role in the formation of the signature vascular lesions of diabetic retinopathy (Joussen, A.M., FASEB J., 2001 , 18. 1450). Inhibition of the SSAO activity leads to a decrease in the formation of AGEs and in oxidative stress. Moreover, a specific VAP-I inhibitor was reported to have beneficial effects in an uveitis model (endotoxin- induced uveitis) (Noda, K., FASEB J., 2008, 22, 1094-1 103). Thiazole VAP-I inhibitors were disclosed as useful for the treatment of macular edema (VVO 2006/028269, WO 2006/01 1631, WO 2004/067521 ). In an animal model of diabetes, the treatment with the inhibitor exhibited a beneficial effect on the increased vascular permeability in the eyes (WO 2004/067521). The strong SSAO inhibitor aminoguanidine has beneficial effect on diabetic retinopathy in animal model (Ellis, E.N., et al., Metabolism, 1991 , 40, 1016), its effect might be related to its SSAO inhibition.

Considering the above detailed aspects, it is reasonable to suggest that application of pharmaceutical compositions of SSAO/V AP- 1 inhibitors could be a novel, effective approach for the treatment of inflammatory eye diseases. Currently there is not any drug available in therapy exploiting this approach.

In SSAO enzyme catalysis the carbonyl group containing topaquinone cofactor has a central role, analysis of its structure may serve as a sound basis for the design of inhibitor compounds. The name of SSAO derives from its sensitivity to inhibition by semicarbazide. Besides semicarbazide, the well-known inhibitor of SSAO, also other classes of compounds were described as inhibitors, such as several hydrazine derivatives. Among the drugs already used in therapy containing hydrazino group, several were reported to have SSAO inhibitory effect, such as hydralazine, carbidopa and benserazide (Matyus, P. et al., Curr. Med. Chem., 2004, 1 1, 1285-1298). None of these compounds has been used however for the treatment of diseases related to elevated SSAO activity, said diseases including diabetic complications, such an application of these drugs was not even suggested previously.

An underlying reason of that could be, that the primary effect of these drugs that serve as the basis of their recent use in therapy (e.g. antihypertensive effect), may be a serious adverse effect in course of their use for the treatment of diseases related to elevated SSAO activity, such as retinopathy.

The growing interest in hydrazino derivatives however is well illustrated by the recent disclosure of several SSAO inhibitor hydrazino derivatives, e.g. some hydrazinoalcohol derivatives (WO 2005/080319, WO 2002/002090); hydrazinoindane derivatives (WO 2003/006003); and phenylallylhydrazine derivatives (Wang, E. Y. et al., J. Med. Chem., 2006, 49, 2166-2173, WO 2006/094201). According to the patent publications, these compounds could be useful for the treatment of acute and chronic inflammations, diseases related to carbohydrate metabolism, diseases related to adipocyte differentiation or dysfunction, diseases related to smooth muscle dysfunctions and vascular diseases.

Disclosure of the invention

Dihydralazine has long been used in human therapy as an antihypertensive agent. Despite its structural analogy with hydralazine (dihydralazine may be regarded as a substituted hydralazine), no data have been published previously on the effect of dihydralazine on SSAO. In spite of the structural resemblance of dihydralazine to hydralazine, the SSAO inhibitory activity of dihydralazine is far from being evident, due to the observations that even slight structural modifications in hydrazine derivatives may significantly influence the type and magnitude of SSAO inhibitory activity (Lizcano, J. M. et al., Biochem. Pharmacol., 1996, 52, 187-195). The SSAO inhibition by dihydralazine was confirmed by our experiments described in the examples. Therapeutic application of dihydralazine as an SSAO inhibitor may be more advantageous than that of hydralazine, as a consequence of the presence of one more hydrazino group in dihydralazine. It is well known that the hydrazino group of hydralazine and one of the hydrazino groups of dihydralazine undergo metabolic inactivation (Schneider, T. et al., Pharmazie, 1988, 43, 33-36, ibidem. 704-706), the other, metabolically intact hydrazino group of dihydralazine may therefore be available for SSAO inhibition that may result in particularly preferable pharmacokinetic and phamacodynamic properties of dihydralazine as SSAO inhibitor.

The present invention relates to the use of dihydralazine for the treatment of diseases related to elevated levels of SSAO activity.

In another embodiment, the present invention relates to the use of dihydralazine for manufacture of a pharmaceutical composition for the treatment of diseases related to elevated levels of SSAO activity. The diseases related to elevated SSAO activity of the above embodiments include: acute or chronic inflammatory conditions and diseases related to elevated SSAO activity, connective tissue inflammatory conditions and diseases, rheumatoid arthritis, ankylosing spondylitis, lupus erythematosus, vasculitis, synovitis, gastrointestinal inflammatory conditions and diseases, ulcerative colitis, Crohn's disease, irritable bowel syndrome, central nervous system inflammatory conditions and diseases, Alzheimer's disease, multiple sclerosis, pulmonary inflammatory conditions and diseases, asthma, inflammatory skin conditions, psoriasis, contact dermatitis, atopic dermatitis, liver inflammatory conditions and diseases, inflammatory conditions and diseases of the eye (eyeball, accessory and protective structures of the eye, orbit), macular edema, diseases related to carbohydrate metabolism, diseases related to adipocyte differentiation or dysfunction, diseases related to smooth muscle cell dysfunction, atherosclerosis, obesity, vascular diseases, arteriosclerosis, Raynaud's disease. In the above embodiments, diseases related to carbohydrate metabolism include diabetes (type 1 or type

2), diabetes related vascular complications and/or neuropathy and/or retinopathy and/or nephropathy, particularly diabetic retinopathy and macular edema.

It should be noted, that according to our animal experiments, dihydralazine is able to exhibit significant SSAO inhibition in such a low dose, that does not cause appreciable (i.e. appreciable to the animal or human treated) blood pressure lowering effect. Thus, in a preferred embodiment of the invention dihydralazine is used for the inhibition of SSAO activity in such a dose, which does not cause appreciable lowering in blood pressure in the animal or human treated under the normal levels. However, in patients with hypertension, lowering of blood pressure, i.e. antihypertensive effect could be beneficial, therefore, in case of such patients, even higher doses (depending on the degree of hypertension) than the ones described below as preferred embodiments of the invention can be used.

In one embodiment, the invention relates to the use of dihydralazine in therapy per se or with one or more additional compounds in combination. In another embodiment, dihydralazine can be used per se or in combination with one or more additional compounds for the manufacture of a pharmaceutical composition.

Detailed description of the invention

The pharmaceutical compositions of the present invention can be administered by any means that achieve their intended purpose. Routes of administration of the present invention can be, for example, oral, intravenous, intramuscular, subconjunctival, parabulbar, retrobulbar, subtenon, intracameral, intravitreal and other injections, sublingual, transdermal, ocular, eye drops, eye gels or ointments. Compositions of the present invention can be solid, semisolid or liquid. Potential liquid compositions of the present invention include but are not limited to solutions, tinctures, syrups, emulsions and suspensions.

The pharmaceutical compositions of the present invention can contain one or more non-toxic, pharmaceutically acceptable excipients (e.g. agents used for formulation, carriers, surface acting agents, colours, sweeteners, solvents, suspending agents, coatings etc.). Preferred embodiments are controlled-release compositions and compositions providing an organ specific targeted delivery of the active ingredient.

Pharmaceutical compositions of the present invention can be prepared by admixing the active ingredient dihydralazine or its salt (preferred are for example sulphate, hydrochloride salts) with one or more excipients and by formulation to a pharmaceutical composition. Pharmaceutical compositions can be prepared by methods and contain excipients which are well known in the art. A generally recognized compendium of such methods and ingredients is Remington's Pharmaceutical Sciences.

In one embodiment, dihydralazine is administered in a dose of 0.005-1.5 mg/bodyweight kg. In a preferred embodiment, dihydralazine is administered in a dose of 0.2- 1 mg/bodyweight kg, in a more preferred embodiment, in a dose of 0.4-0.8 mg/bodyweight kg, if the preferred embodiment of administering the active ingredient without causing appreciable lowering of blood pressure is intended to be carried out. These dosage intervals are related to administration to humans and can be used for the administration to animals just with the appropriate interpolation.

Pharmaceutical compositions of the invention in a preferred embodiment contain single doses. The exact dosage administered will be dependent upon a variety of factors and can be chosen by the individual physician in view of the appropriate parameters (weight of the recipient, age, stage and degree of the disease etc).

As demonstrated by Example 3, in adults of average weight (approx. 70 kg), administration of 14.5 mg dihydralazine sulphate two times daily was found to be preferable (no appreciable lowering of blood pressure was observed). The effect of dihydralazine was studied in Micromedex/Drugdex evaluations. In the treatment of hypertension, dihydralazine is indicated as supplemental therapy as a second or third drug. Dihydralazine therapy is initiated with lower doses (eg, 12.5 to 25 milligrams twice daily), with gradual dose increases based on clinical response and tolerability to total daily doses of 25 to 100 milligrams in 2 or 3 divided doses (Strocchi E. et al., Int. J. Clin. Pharmacol. Ther. Toxicol., 1983, 21, 519-523; Komajda M. et a!., Am. J. Nephrol., 1986, 6(suppl 2), 106-1 12; Thibonnier M. et al., Br. J. Clin. Pharmacol., 1980, 9, 561-567; Salmela P.I. et al., Ann. Clin. Res., 1981, 13, 433-438; Sassano P. et al., Am. J. Med., 1987, 83, 227-235). Higher doses (150 milligrams/day) have been used in some studies (Kirch W. & Axthelm T., J. Cardiovasc. Pharmacol., 1982, 4, 562-566).

In one embodiment, the invention relates to the use of dihydralazine in therapy per se or with one or more additional active ingredients in combination. In another embodiment, dihydralazine can be used per se or in combination with one or more additional active ingredients for the manufacture of a pharmaceutical composition. Preferred additional active ingredients of the invention are agents inhibiting SSAO activity and/or anti-inflammatory agents and/or VEGF inhibitors and/or VEGF small interfering RNA agents and/or tyrosine kinase inhibitors and/or protein kinase C inhibitors and/or angiotensin converting enzyme (ACE) inhibitors and/or PPAR-γ inhibitors and/or acetylsalicylic acid and/or statins (statin type compounds, abbreviated: statins), and/or compounds used for the treatment of diabetes and/or its pathological consequences.

Preferred additional active ingredients can be: VEGF inhibitors, as for example pegaptanib (Macugen), ranibizumab (Lucentis), bevacizumab (Avastin), vatalanib; VEGF Trap; VEGF small interfering RNA agents, as for example bevasiranib, Sirna-027; PPAR-γ inhibitors, as for example glitazones; tyrosine kinase inhibitors, as for example ALN-VEGOl, AG-013958; steroid or non-steroid anti- inflammatory agents.

The invention is illustrated by the following non-restrictive experimental examples.

Example 1 Study of the effect of dihydralazine on human serum SSAO activity

In the experiment human serum was used in the following way: blood samples were collected without anticoagulant, then stored at 4°C for 15 minutes and centrifuged (4°C, 2500 g/10 min). The supernatant was stored at -80⁰C until the measurement of the enzyme activity. A radiochemical procedure (Yu P.H., Zuo D. M., Biochem. Pharmacol., 1992, 43, 307-312) was adapted for determining SSAO activities in the human serum. It is based on the determination of the quantity of '⁴C- benzaldehyde formed by the enzyme reaction of ^l4C-benzylamine.

The preparations containing the serum and the dihydralazine enzyme inhibitor were pre-incubated at room temperature for 20 min. The enzyme reaction was started with ¹⁴C-benzyIamine substrate (~ 200000 dpm/tube). During the experiments 200 μl was the final volume of the incubation media, the composition of which is shown in Table 1. The samples obtained accordingly were incubated at 37°C for 40 min, then the reaction was stopped by adding 200 μl 2M citric acid solution. In case of the 'blank' sample, citric acid solution was added before adding the substrate, therefore, in this case no enzyme reaction took place. The samples were extracted with 1000 μl 1 : 1 toluene - ethyl acetate mixture, by vortex method, then centrifuged (2500 g / 5 min). The enzyme activity was determined by liquid scintillation counting (600 μl supernatant + 5ml Aquasafe), using the formula below:

fdpm (sample) - dpm 0'1 x 1.6 x IQ x 1.5 measured substrate activity dpm x mg protein

standing for: 1.6: extraction volume; 10: molar activity; 1.5: correction factor for the incubation time; dpm: disintegrations per minute (unit of radioactivity)

The inhibition was calculated in the % inhibition compared to the control ('control' sample not containing the inhibitor compound) after correction with the background ('blank' sample). The method used for the determination of the protein quantity of the samples is based on comparison of the 100Ox dilution of the plasma to the standard calibration curve of serum albumin (Bradford M. M., Anal. Biochem. 72, 248, 1976). The % inhibition can be determined also of the dpm values of the control and the sample. Table 1.

Composition of the incubation media

According to the assay, the IC_2O value of dihydralazine on human serum SSAO is 0.5 μM.

Example 2

Effect of dihydralazine on the SSAO activity in vivo in rats

Rats were treated sc with 0.1 or 0.01 M dihydralazine solution (0.1 ml/100 g) once daily for 1-5 days.

On the appropriate day, 2 hours after the treatment the rats were decapitated and their blood was collected without anticoagulant in plastic centrifuge tubes. Blood samples were centrifuged at a low frequency (800 rpm/min) and the supernatant was used for the determination of SSAO activity applying ¹⁴C-benzylamine substrate.

SSAO inhibition expressed in pmol/mg protein/hour units and in % values (mean + S.D.) in the two treated groups is shown in table 2 and 3. The blood pressure of the animals was determined in an invasive way. In treated animals, compared to the control group, the treatment did not cause lowering of the blood pressure.

Table 2

Effect of dihydralazine on SSAO activity in vivo (1.)

Table 3

Effect of dihydralazine on SSAO activity in vivo (2.)

Example 3

Study of the effect of dihydralazine on the macular edema of type 2 diabetic patients and on the SSAO activity The effect of orally administered low dose dihydralazine on macular edema and serum SSAO activity was studied in type 2 diabetic patients in an early stage of macular edema formation.

After giving their informed consent, patients participating in the study were treated for 56 days taking V₂ tablet twice daily of a pharmaceutical composition containing 28.9 mg dihydralazine sulphate (i.e. the V₂ tablet contained 14.5 mg dihydralazine sulphate). To measure the efficacy and monitor the safety of the treatment, the following examinations were carried out before starting the treatment and at the 1., 7., 14., 28. and 56. day of the treatment:

1. ocular examinations: visual acuity (ETDRS chart), slit-lamp examination, measurement of intraocular pressure with applanation tonometry, fundus biomicroscopy with pupil dilation, digital fundus photography. The grade of macular edema was determined via measuring retinal thickness with optical coherency tomography (OCT).

2. internal medicine examinations: anamnesis, physical examinations, blood pressure, pulse, urine examination.

3. laboratory examinations: blood glucose, HbAIc, liver function, kidney function, microalbuminuria, metabolic panel of the blood , lipids, CRP. Serum SSAO activity was determined from blood samples collected before starting the treatment, and at the 14., 28. and 56. day of the treatment. The blood samples were centrifuged and the supernatant was stored at - 80⁰C until the measurement of the enzyme activity. SSAO activity was determined applying the method described in the example above.

The table below (Table 4) summarizes the data of 2 treated patients. In the presented cases, significant decrease of the macular edema was observed in the fovea, the most important anatomical location of the retina responsible for central sharp vision, with a parallel decrease of serum SSAO activity. As illustrated by the data, the applied dose did not cause significant change of blood pressure. In the table the following abbreviations were used: BMI: body mass index - weight (kg) / height² (m²) RRsyst: blood pressure (systolic) (Hgmm)

RRdiast: blood pressure (diastolic) (Hgmm)

OCT CST (central subfield thickness): the average thickness of the central 1-mm area of the macula OCT CPT (center point thickness): the thickness of the center point of the retina; normally that is the thinnest point of the macula

Table 4.

Data of the patients' treated

Claims

1. Dihydralazine for use in the treatment of diseases related to elevated levels of SSAO activity.

2. Use of dihydralazine for manufacture of a pharmaceutical composition for the treatment of diseases related to elevated levels of SSAO activity.

3. Method for the treatment of diseases related to elevated levels of SSAO activity in a mammal in need thereof, which comprises administering to said mammal an effective amount of dihydralazine.

4. The product or use or method according to any of of claims 1 to 3, wherein said SSAO related disease is selected from the group consisting of: acute or chronic inflammatory conditions and diseases related to elevated SSAO activity, connective tissue inflammatory conditions and diseases, rheumatoid arthritis, ankylosing spondylitis, lupus erythematosus, vasculitis, synovitis, gastrointestinal inflammatory conditions and diseases, ulcerative colitis, Crohn's disease, irritable bowel syndrome, central nervous system inflammatory conditions and diseases, Alzheimer's disease, multiple sclerosis, pulmonary inflammatory conditions and diseases, asthma, inflammatory skin conditions, psoriasis, contact dermatitis, atopic dermatitis, liver inflammatory conditions and diseases, inflammatory conditions and diseases of the eye (eyeball, accessory and protective structures of the eye, orbit), macular edema, diseases related to carbohydrate metabolism, diseases related to adipocyte differentiation or dysfunction, diseases related to smooth muscle cell dysfunction, atherosclerosis, obesity, vascular diseases, arteriosclerosis, Raynaud's disease.

5. The use of claim 4, wherein said diseas related to carbohydrate metabolism is type 1 or type 2 diabetes, diabetes related vascular complications and/or neuropathy and/or retinopathy and/or nephropathy, particularly diabetic retinopathy and macular edema.

6. The use of claim 1-5, wherein dihydralazine is administered to decrease SSAO activity in such a dose, that does not lead to appreciable lowering of blood pressure in the animal or human treated.

7. The use of claim 6, wherein dihydralazine is administered in a 0.005-1.5 mg/weight kg, preferably in a 0.2-1 mg/weight kg, more preferably in a 0.4-0.8 mg/weight kg dose.

8. The use of claim 1-7, wherein dihydralazine is administered in combination with one or more additional active ingredients, preferably in combination with other agents inhibiting SSAO activity and/or anti- inflammatory agents and/or VEGF inhibitors and/or VEGF small interfering RNA agents and/or tyrosine kinase inhibitors and/or protein kinase C inhibitors and/or angiotensin converting enzyme (ACE) inhibitors and/or PPAR-γ inhibitors and/or acetylsalicylic acid and/or statin type compounds and/or compounds used for the treatment of diabetes and/or its pathological consequences.