Antithrombotic activity of a glycosaminoglycan (sulodexide) in rats

Sulodexide attenuates endoplasmic reticulum stress induced by myocardial ischaemia/reperfusion by activating the PI3K/Akt pathway

Acute myocardial ischaemia/reperfusion (MI/R) injury causes severe arrhythmias with a high rate of lethality. Extensive research focus on endoplasmic reticulum (ER) stress and its dysfunction which leads to cardiac injury in MI/R Our study evaluated the effects of sulodexide (SDX) on MI/R by establishing MI/R mice models and in vitro oxidative stress models in H9C2 cells. We found that SDX decreases cardiac injury during ischaemia reperfusion and decreased myocardial apoptosis and infarct area, which was paralleled by increased superoxide dismutase and reduced malondialdehyde in mice plasm, increased Bcl‐2 expression, decreased BAX expression in a mouse model of MI/R. In vitro, SDX exerted a protective effect by the suppression of the ER stress which induced by tert‐butyl hydroperoxide (TBHP) treatment. Both of the in vivo and in vitro effects were involved in the phosphatidylinositol 3‐kinase (PI3K)/Akt signalling pathway. Inhibition of PI3K/Akt pathway by specific inhibitor, LY294002, partially reduced the protective effect of SDX. In short, our results suggested that the cardioprotective role of SDX was related to the suppression of ER stress in mice MI/R models and TBHP‐induced H9C2 cell injury which was through the PI3K/Akt signalling pathway.

Sulodexide promotes arterial relaxation via endothelium-dependent nitric oxide-mediated pathway

Sulodexide (SDX) is a highly purified glycosaminoglycan with antithrombotic and profibrinolytic properties and reported benefits in thrombotic and atherosclerotic vascular disorders. However, the effects of SDX on vascular function are unclear. We tested whether SDX affects vascular relaxation and examined the potential underlying mechanisms. Isolated segments of male rat abdominal aorta and mesenteric artery were suspended in a tissue bath, and the changes in arterial contraction/relaxation were measured. The α-adrenergic receptor agonist phenylephrine (Phe) (10^-9-10^-5 M) caused concentration-dependent aortic and mesenteric artery contraction that was reduced in tissues pretreated with SDX (1 mg/ml). In aortic and mesenteric arterial segments precontracted with submaximal concentration of Phe (3 × 10^-7-6 × 10^-7 M), SDX (0.001-1 mg/ml) caused concentration-dependent relaxation. To test the role of endothelium, SDX-induced relaxation was compared with that of acetylcholine (ACh), a known activator of endothelium-dependent relaxation. In Phe precontracted aorta, ACh relaxation was abolished and SDX relaxation was significantly inhibited by endothelium removal or the nitric oxide synthase (NOS) inhibitor N_ω-nitro-l-arginine methyl ester (L-NAME), suggesting a role of NO. In mesenteric artery, ACh relaxation was abolished by endothelium removal, partially blocked by L-NAME, and completely blocked by a mixture of indomethacin, a cyclooxygenase inhibitor and blocker of the PGI₂-cAMP pathway, and tetraethylammonium, a blocker of K⁺ channels and EDHF-dependent hyperpolarization pathway. In comparison, SDX relaxation of mesenteric artery was almost completely inhibited by endothelium removal or NOS inhibitor L-NAME. SDX enhanced vascular relaxation and increased nitrate/nitrite production in response to all ACh concentrations in the aorta, but only to low ACh concentrations (<10^-7 M) in mesenteric artery. SDX did not affect aortic or mesenteric artery endothelium-independent relaxation to the NO donor sodium nitroprusside. Thus, SDX promotes arterial relaxation via a mechanism involving endothelium-dependent NO production; an effect that could enhance vasodilation and decrease vasoconstriction in vascular disorders.

Development and use of sulodexide in vascular diseases: implications for treatment

Sulodexide (SDX), a sulfated polysaccharide complex extracted from porcine intestinal mucosa, is a blend of two glycosaminoglycan (GAG) entities, namely a fast-moving heparin (HP) fraction and a dermatan sulfate (DS; 20%) component. The compound is unique among HP-like substances in that it is biologically active by both the parenteral and oral routes. A main feature of the agent is to undergo extensive absorption by the vascular endothelium. For this reason, in preclinical studies, SDX administered parenterally displays an antithrombotic action similar to that of HPs but associated with fewer alterations of the blood clotting mechanisms and tests, thus being much less conducive to bleeding risk than HPs. When given orally, SDX is associated with minimal changes in classic coagulation tests, but maintains a number of important effects on the structure and function of endothelial cells (EC), and the intercellular matrix. These activities include prevention or restoration of the integrity and permeability of EC, counteraction versus chemical, toxic or metabolic EC injury, regulation of EC-blood cell interactions, inhibition of microvascular inflammatory and proliferative changes, and other similar effects, thus allowing oral SDX to be considered as an endothelial-protecting agent. The best available clinical evidence of the efficacy of SDX administered orally with or without an initial parenteral phase is the following: alleviation of symptoms in chronic venous disease and especially acceleration of healing of venous leg ulcers; prevention of cardiovascular events in survivors after acute myocardial infarction; marked improvement of intermittent claudication in patients with peripheral occlusive arterial disease; and abatement of proteinuria in patients with diabetic nephropathy that may contribute to the amelioration or stabilization of kidney function. Although further clinical trials are warranted, SDX is presently widely accepted in many countries as an effective and safe long-term, endothelial-protecting drug.

Therapeutic Modalities in Diabetic Nephropathy: Future Approaches

Diabetes mellitus is the leading cause of end stage renal disease and is responsible for more than 40% of all cases in the United States. Several therapeutic interventions for the treatment of diabetic nephropathy have been developed and implemented over the past few decades with some degree of success. However, the renal protection provided by these therapeutic modalities is incomplete. More effective approaches are therefore urgently needed. Recently, several novel therapeutic strategies have been explored in treating DN patients including Islet cell transplant, Aldose reductase inhibitors, Sulodexide (GAC), Protein Kinase C (PKC) inhibitors, Connective tissue growth factor (CTGF) inhibitors, Transforming growth factor-beta (TGF-β) inhibitors and bardoxolone. The benefits and risks of these agents are still under investigation. This review aims to summarize the utility of these novel therapeutic approaches.

Anti-proteinuric effect of sulodexide in immunoglobulin a nephropathy

PURPOSE

We conducted a multi-center randomized double-blind study to determine the effects of 6-month therapy with sulodexide on urinary protein excretion in patients with idiopathic Immunoglobulin A (IgA) nephropathy.

MATERIALS AND METHODS

A total of seventy-seven patients participated in the study. They were randomly allocated to one of three groups: sulodexide 75 mg or 150 mg daily or the placebo for 6 months. The primary end point was the achievement, at 6 months, of at least 50% reduction in urine protein/creatinine ratio (UPCR) from the baseline value.

RESULTS

At 6 months, the primary end point was achieved by 12.5% of the patients assigned to the placebo, 4.0% of the patients assigned to sulodexide 75 mg daily and 21.4% of those assigned to 150 mg (p=0.308). Treatment with sulodexide 150 mg daily for 6 months significantly reduced log UPCR from 6.38±0.77 at baseline to 5.98±0.94 at 6 months (p=0.045), while treatment with sulodexide 75 mg daily and placebo did not.

CONCLUSION

A 6-month treatment with sulodexide did not achieve 50% reduction of urinary protein excretion in IgA nephropathy patients, but showed a tendency to increase the time-dependent anti-proteinuric effect. Therefore, long-term clinical trials on a larger scale are warranted to elucidate the hypothesis that sulodexide affords renal protection in IgA nephropathy patients.

Sulodexide: a renewed interest in this glycosaminoglycan

Glycosaminoglycans (GAGs) are the most abundant group of heteropolysaccharides found in the body. These long unbranched molecules contain a repeating disaccharide unit. GAGs are located primarily in the extracellular matrix or on the surface of cells. These molecules serve as lubricants in the joints while at the same time providing structural rigidity to cells. Sulodexide is a highly purified glycosaminoglycan composed of a fast mobility heparin fraction as well as dermatan sulfate. Sulodexide differs from other glycosaminoglycans, like heparin, by having a longer half-life and a reduced effect on systemic clotting and bleeding. In addition, sulodexide demonstrates a lipolytic activity that is increased in comparison to heparin. Oral administration of sulodexide results in the release of tissue plasminogen activator and an increase in fibrinolytic activities. An increasing body of research has demonstrated the safety and efficacy of sulodexide in a wide range of vascular pathologies.

A study on the safety, efficacy, and efficiency of sulodexide compared with acenocoumarol in secondary prophylaxis in patients with deep venous thrombosis

This study was carried out to study the safety and efficacy of a fixed dosage of sulodexide compared to adjusted dosages (INR) of acenocoumarol as secondary prophylaxis in patients with deep vein thrombosis (DVT) in lower limbs. An economic evaluation based on the criteria of use in normal clinical practice was also performed. One hundred and fifty patients of both sexes were included, all over 18 years of age and diagnosed with proximal DVT of the lower limbs by color echo-Doppler, and with clinical evolution of less than 1 month. The patients were initially treated with low-molecular-weight heparin (LMWH) and urokinase in accordance with the established protocol. They were then randomized to continue treatment with acenocoumarol and INR adjustments every 30 days, or with sulodexide. Treatment was extended for 3 months with monthly follow-up visits and a final visit at 3 months posttreatment. No differences between the groups were detected concerning demographic or basal characteristics in clinical evolution or adverse reactions. In the group treated with sulodexide, no major/minor hemorrhagic complications were detected. On the other hand, in the acenocoumarol group, 1 major hemorrhage and 9 minor hemorrhages were produced (13.3%), reaching statistical difference in relation to the sulodexide group (p = 0.014; CI from 95% of 4.7% to 19.4%). Regarding the economic impact, treatment costs with sulodexide are much less than those with acenocoumarol, the data confirmed by the sensitivity analyses performed. The results prove the efficacy, safety, and efficiency of sulodexide as a secondary prophylaxis in thromboembolic disease, avoiding hemorrhagic risks and the monitoring of patients, and providing significant savings to the health system.

Review of pharmacodynamics, pharmacokinetics, and therapeutic properties of sulodexide

Due to various side effects of heparin, such as heparin-induced thrombocytopenia type I or type II, alternative anticoagulants are in clinical development to optimize the anticoagulant regimes in patients requiring low or high anticoagulation dosages. Sulodexide is a highly purified preparation containing a fast-moving heparin fraction as well as dermatansulfate. The pharmacological effects of sulodexide differ substantially from unfractionated heparin and are mainly characterized by a prolonged half-life and reduced effect on global coagulation and bleeding parameters. The lipolytic activity of sulodexide is increased in comparison to unfractionated heparin. Clinical studies demonstrate the safety and efficacy of sulodexide. Specially, oral administration leads to fibrinolytic activities in contrast to oral administration of other glycosaminoglycans. Thus, sulodexide releases tissue plasminogen activator and decreases fibrinogen levels as well as HDL and total cholesterol levels and blood viscosity. Clinical efficacy is demonstrated in peripheral arterial disease, cardiovascular events, in postphlebitic syndrome and on albuminuria in nephropathy.

Sulodexide versus calcium heparin in the medium-term treatment of deep vein thrombosis of the lower limbs

Thirty adult patients with distal, monolateral deep vein thrombosis of the lower limbs were randomly treated for sixty days either with subcutaneous Ca-Heparin or with Sulodexide, administered IM for ten days and orally for fifty days. The thrombus accretion above the knee, the venous pressures of the affected leg, the clinical symptomatology, and some laboratory coagulative tests were monitored throughout the administration period. Local tolerability of the two treatments was also evaluated. The two applied treatments evidenced a net antithrombotic activity, preventing thrombus accretion above the knee, improving with the same efficacy the venous pressures in the affected legs, and similarly reducing clinical symptoms, with a quick and statistically significant trend toward normalization. Blood fibrinogen was significantly lowered by both drugs, while only Ca-heparin yielded a prolongation of activated partial thromboplastin time. Local tolerability of treatments was better for the mainly oral Sulodexide administrations, while subcutaneous Ca-heparin often induced small, though transient, hematomas.

Vascular dementia Italian sulodexide study (VA.D.I.S.S.). Clinical and biological results

In order to evaluate the biological effects on some haemostasis factors of antithrombotic-hemorheological treatments on patients with vascular dementia, a multicenter, randomized, double-blind, double-dummy, study comparing sulodexide (Sdx, 50 mg bid orally for 6 months) and pentoxifylline (Ptx, 400 mg tid orally for six months) was carried out. Eighty-six patients, 46 in Sdx group, 40 in Ptx group, fulfilling the NINDS-AIREN criteria for probable vascular dementia were evaluated. Plasma fibrinogen levels showed a significant reduction in both groups, in patients with high basal levels (> or = 350 mg/dl), the reduction being earlier in Sdx group (2nd month of therapy) than in Ptx group (4th month of therapy). In Sdx group a significant reduction in factor VII-Ag (baseline 102.8 U/dl; 6th month 90.1 U/dl) was also observed. Both drugs induced a slight reduction in activated factor VII levels as well. A parallel improvement of G.B.S. Rating Scale for dementia scores was observed in Sdx group. These results seem to indicate that sulodexide treatment can have positive effects in vascular dementia.

Meta-analysis of some results of clinical trials on sulodexide therapy in peripheral occlusive arterial disease

The aim was to look at the effect of sulodexide in diabetic and non-diabetic patients with peripheral occlusive arterial disease (POAD), by verifying, through meta-analysis of Italian data, if the drug affects the clinical course of claudication or the main risk factors for POAD. Sulodexide increases the pain-free walking distance (benefit 36% vs controls, P < 0.001). The meta-analysis confirmed the effectiveness of sulodexide in improving claudication (lower limit of the 95% CI for overall odds ratio always > 1). There was a marked effect in lowering triglycerides (overall -28%, P = 0.0015), fibrinogen (-13%, P < 0.0001) and plasma and serum viscosities, and in increasing high-density-lipoprotein cholesterol (24.4%, P = 0.0007). The medium-term administration of sulodexide has a therapeutic effect on claudication of diabetic and/or hyperlipidaemic patients suffering from POAD stages- and also counteracts several POAD risk factors. Long-term use of sulodexide appears to be well tolerated. The treatment has a low daily cost; therefore, it has a favourable cost-benefit ratio, in view of the high general costs associated with global POAD care, particularly in diabetic patients.

Novel antithrombotic drugs in development

Platelet activation plays a critical role in thromboembolic disorders, and aspirin remains a keystone in preventive strategies. This remarkable efficacy is rather unexpected, as aspirin selectively inhibits platelet aggregation mediated through activation of the arachidonic-thromboxane pathway, but not platelet aggregation induced by adenosine diphosphate (ADP), collagen and low levels of thrombin. This apparent paradox has stimulated investigations on the effect of aspirin on eicosanoid-independent effects of aspirin on cellular signalling. It has also fostered the search for antiplatelet drugs inhibiting platelet aggregation at other levels than the acetylation of platelet cyclo-oxygenase, such as thromboxane synthase inhibitors and thromboxane receptor antagonists. The final step of all platelet agonists is the functional expression of glycoprotein (GP) IIb/IIIa on the platelet surface, which ligates fibrinogen to link platelets together as part of the aggregation process. Agents that interact between GPIIb/IIIa and fibrinogen have been developed, which block GPIIb/IIIa, such as monoclonal antibodies to GPIIb/IIIa, and natural and synthetic peptides (disintegrins) containing the Arg-Gly-Asp (RGD) recognition sequence in fibrinogen and other adhesion macromolecules. Also, some non-peptide RGD mimetics have been developed which are orally active prodrugs. Stable analogues of prostacyclin, some of which are orally active, are also available. Thrombin has a pivotal role in both platelet activation and fibrin generation. In addition to natural and recombinant human antithrombin III, direct antithrombin III-independent thrombin inhibitors have been developed as recombinant hirudin, hirulog, argatroban, boroarginine derivatives and single stranded DNA oligonucleotides (aptanes). Direct thrombin inhibitors do not affect thrombin generation and may leave some 'escaping' thrombin molecules unaffected. Inhibition of factor Xa can prevent thrombin generation and disrupt the thrombin feedback loop that amplifies thrombin production.

IPO-V2: a prospective, multicenter, randomized, comparative clinical investigation of the effects of sulodexide in preventing cardiovascular accidents in the first year after acute myocardial infarction

OBJECTIVES

This study was conducted to assess the efficacy of sulodexide, a glycosaminoglycan compound with antithrombotic properties, in preventing death and thromboembolic events after acute myocardial infarction.

BACKGROUND

Antithrombotic therapy has been found to play an important role in the prevention of cardiovascular events and death after acute myocardial infarction. Glycosaminoglycan-containing compounds, including sulodexide, show profibrinolytic and antithrombotic properties that render them suitable for use in patients after infarction.

METHODS

A total of 3,986 patients who had recovered from acute myocardial infarction were randomized to receive either the standard therapy routinely administered at each study center, excluding antiplatelet and anticoagulant drugs (control group, 1,970 patients), or the standard therapy plus sulodexide (treated group, 2,016 patients). Between 7 and 10 days after the episode of acute myocardial infarction, sulodexide was administered as a single daily 600-lipoprotein-lipase-releasing unit (LRU) intramuscular injection for the 1st month, followed by oral capsules of 500 LRU twice daily. Patients were evaluated for > or = 12 months.

RESULTS

At the end of the study, 140 deaths (7.1%) were recorded in the control group and 97 (4.8%) in the sulodexide group (32% risk reduction, p = 0.0022, chi-square test). A total of 90 patients (4.6%) in the control group had a further infarction, compared with 66 (3.3%) in the sulodexide group (28% risk reduction, p = 0.035). Furthermore, a reduction in left ventricular thrombus formation (evaluated by echocardiography) was observed in the sulodexide group (n = 12; 0.6%), compared with values in the control group (n = 25; 1.3%) (53% risk reduction, p = 0.027). Sulodexide was well tolerated and devoid of significant adverse events. All significant results were confirmed by "actual treatment" analyses.

CONCLUSIONS

The study provides evidence that long-term therapy with sulodexide started early after an episode of acute myocardial infarction is associated with reductions in total mortality, rate of reinfarction and mural thrombus formation.

Pharmacodynamic effects of single and repeated doses of oral sulodexide in healthy volunteers. A placebo-controlled study with an enteric-coated formulation

Eight male and 8 female healthy volunteers, aged on average 32 +/- 6 years, underwent a randomized, crossover study, aimed at comparing the activity on some fibrinolysis and coagulation parameters of 100 and 200 mg/day of oral sulodexide, administered as enteric-coated tablets. After the single and the repeated (for 7 days) administration of the two daily dosages, the Fibrin Plates test, the Heptest, the Plasminogen Activator Inhibitor test (as to both activity and antigen level) and the activated Partial Thromboplastin Time were checked during the first 6 hours after administration. The pro-fibrinolytic and antithrombotic activity of sulodexide was confirmed to be significant with both dosage schemes and potentiated by repeated administrations. On the other hand, the absence of any influence on aPTT confirmed the lack of interference of the drug, after oral administration, on the intrinsic pathway of coagulation. No adverse reactions or events were observed.

Double-blind, double-dummy, randomized, multi-centre clinical assessment of the efficacy, tolerability and dose-effect relationship of sulodexide in chronic venous insufficiency

A multi-centre study was carried out in 476 patients with chronic venous insufficiency to compare the efficacy, tolerability and dose-effect relationship of sulodexide given orally as either capsules or as a new, enteric-coated tablet formulation. Three comparable groups of patients each with chronic venous insufficiency of thrombotic or varicose aetiology received during 60 consecutive days either sulodexide 250 LRU (= 25 mg) capsules twice daily, 50 mg sulodexide enteric-coated tablets twice daily or 100 mg sulodexide enteric-coated tablets once daily, according to a double-blind, double-dummy, randomized design. Doppler and echoduplex examinations, supine and standing peripheral venous pressure, specific symptoms and signs, peripheral haemodynamics and safety haematology and haematochemistry were monitored monthly. The results showed that peripheral venous pressure improved to a clinically relevant and statistically significant extent in all groups and symptoms and signs were rapidly and significantly relieved. These effects were dose-related, as in both cases the recovery was faster and greater with the 100 mg per day dose however administered. Both the thrombotic and varicose aetiologic sub-groups benefited from treatment to approximately the same extent. Mild to moderate gastro-intestinal adverse experiences occurred in 48 patients evenly split between groups but spontaneously disappeared within 72 hours, none leading to treatment withdrawal. No clinically relevant modifications of peripheral haemodynamics or of safety haematology and haematochemistry was observed. The haemocoagulation parameters failed to exhibit appreciable variations. While the known clinical usefulness of sulodexide 250 LRU (= 25 mg) capsules twice daily was confirmed in this trial, the enteric-coated tablets, 50 mg twice daily or 100 mg once daily, were shown to have greater efficacy and similar tolerability to the standard formulation and dose.

Antithrombotic and thrombolytic activity of sulodexide in rats

We evaluated the ability of sulodexide, an extracted glycosaminoglycan, to prevent thrombus formation and to reduce a stabilized thrombus in a rat venous thrombosis model (vena cava ligature). Injection of sulodexide 10 min before induction of venous stasis, prevented thrombus formation in a dose-dependent manner (median effective dose 0.55 mg/kg). When given to rats with 6-h-old thrombi, sulodexide caused a marked reduction in thrombus size which reached 70% after 2 h with the highest dose tested (2 mg/kg). The effect of sulodexide on established thrombi appears to be due, at least in part, to a fibrinolysis-mediated mechanism, since it was significantly inhibited by epsilon-aminocaproic acid, a well-known antifibrinolytic drug. Treatment with sulodexide did not noticeably affect plasma levels of plasminogen activator and its specific inhibitor. We also showed that fluorescein-labelled sulodexide, when given to animals with 6-h-old thrombi, was present within the thrombi harvested 2 h later, but was then absent from blood. The fluorescence was mainly located in areas filled with amorphous material, that was identified as fibrin by staining with phosphotungstic acid-hematoxylin. No fluorescein-labelled material could be detected in rats treated with fluorescein alone. These findings indicate that, besides preventing venous thrombus formation, sulodexide is able to promote thrombus dissolution by a mechanism that is partly related to local fibrinolysis stimulation.

Sulodexide and the microcirculatory component in microphlebopathies

A double-blind, placebo-controlled study was carried out in 36 patients, aged 30 to 50 years, to evaluate the effectiveness of oral sulodexide in the treatment of chronic venous insufficiency due to idiopathic varices. Patients were allocated at random to receive either oral sulodexide as 2 capsules (each containing 250 lipoproteinolipase releasing units) twice daily or 2 identical placebo capsules twice daily over a period of 45 days. Using strain gauge plethysmographic data, assessments were made of the microcirculatory effects of treatment by calculating the coefficient of capillary filtration from measurements made on both legs of each patient on entry and after 30 and 45 days of treatment. The coefficient is derived from the transmembranous flow values at the occlusive pressures of 60 and 40 mmHg, the difference between the two occlusive pressures examined and a corrective factor to calculate the capillary pressure based on the pressure in the venous circulation. Statistical analysis of the results showed that sulodexide produced a significant mean reduction from baseline values of the coefficient at both the 30 and 45 day examinations whereas the coefficient increased in the placebo group. The difference between the two groups was also statistically significant. These findings suggest that sulodexide has a positive influence on capillary permeability.

Studies of chemical and biologic properties of a fraction of sulodexide, a heparin-like glycosaminoglycan

The chemical composition and biologic properties of a fraction (f) of Sulodexide, a heparin-like GAG, were studied and compared with those of two sulfated GAG preparations and heparin from intestinal mucosa. f-Sulodexide and the sulfated GAG preparations were fractionated on a Dowex-1Cl- column and subsequently on an antithrombin III affinity column. Low affinity and high affinity fractions had similar chemical composition and lipoprotein lipase releasing ability, but they varied in anticoagulant activity. Low affinity fractions from f-Sulodexide had negligible anticoagulant activity while high affinity fractions had one-half the activity of mucosal heparin. When compared to heparin, both fractions had one third amount of lipoprotein lipase releasing activity. The low anticoagulant activity of f-Sulodexide suggests a suitability for long-term use as an antiatherogenic agent.

The use of sulodexide in the treatment of peripheral vasculopathy accompanying metabolic diseases. Controlled study in hyperlipidemic and diabetic subjects

Thirty vasculopathic subjects with hyperlipoproteinemia (18) and/or diabetes (22) underwent a clinical double-blind study in order to evaluate the effect of sulodexide on lipid and hemorheologic parameters. The experimental design consisted of a first 20-day i.m. therapeutic period with either sulodexide (300 Lipasemic Units twice daily via intramuscular route) or placebo and the following 70 days with the active compound for both groups at the same posology. Results obtained demonstrated that sulodexide yields a hypotriglyceridemic effect on type IV hyperlipoproteinemia and hypofibrinogenic effect, as well. Moreover, this compound exerted a beneficial effect on HDL Cholesterol levels and on the antithrombin III activity by increasing both parameters significantly. Signs and symptoms were alleviated, particularly in the most severe cases of peripheral vascular disease. Insignificant and slight changes were observed at the end of treatments as regards the efficacy of the two administration routes, the i.m. one being more efficacious on lipid parameters and faster acting. No side effects or intolerance were observed during the different periods of the trial.

Antithrombotic and thrombolytic effects of galactan polysulfate (DH 6322) in rats

Anticoagulant, fibrinolytic and thrombolytic effects of galactan polysulfate (DH 6322), a new semi-synthetic polysaccharide sulfate of bacterial origin, were studied in the rat in vitro, ex vivo and in vivo. Addition of DH 6322 to citrated plasma gave a 50% reduction in euglobulin lysis time at around 50 micrograms/ml and a 2-fold prolongation in plasma recalcification time at 40 micrograms/ml. Intravenous injection of DH 6322 caused significant acceleration of euglobulin clot lysis and urokinase-induced plasma clot lysis at doses as low as 2 mg/kg, and also significant prolongation of plasma recalcification time. Oral application of the compound gave similar effects only at an extremely high dose of 3 g/kg. When injected intravenously before induction of pulmonary thrombosis by lactic acid infusion, DH 6322 was found to be effective in preventing thrombus formation. In progressive venous thrombosis induced by insertion of a steel coil into the inferior vena cava, DH 6322 treatment also caused a significant reduction of thrombus size together with increase in the serum levels of fibrin degradation products. The findings indicate that the antithrombotic effects of DH 6322 result from its enhancement of the fibrinolytic potential as well as its anticoagulative action.