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

Electronegative LDL induces MMP-9 and TIMP-1 release in monocytes through CD14 activation: Inhibitory effect of glycosaminoglycan sulodexide

OBJECTIVE

Electronegative LDL (LDL(-)) is involved in atherosclerosis through the activation of the TLR4/CD14 inflammatory pathway in monocytes. Matrix metalloproteinases (MMP) and their inhibitors (tissue inhibitors of metalloproteinase [TIMP]) are also crucially involved in atherosclerosis, but their modulation by LDL(-) has never been investigated. The aim of this study was to examine the ability of LDL(-) to release MMPs and TIMPs in human monocytes and to determine whether sulodexide (SDX), a glycosaminoglycan-based drug, was able to affect their secretion.

APPROACH AND RESULTS

Native LDL (LDL(+)) and LDL(-) separated by anion-exchange chromatography were added to THP1-CD14 monocytes in the presence or absence of SDX for 24 h. A panel of 9 MMPs and 4 TIMPs was analyzed in cell supernatants with multiplex immunoassays. The gelatinolytic activity of MMP-9 was assessed by gelatin zymography. LDL(-) stimulated the release of MMP-9 (13-fold) and TIMP-1 (4-fold) in THP1-CD14 monocytes, as well as the gelatinolytic activity of MMP-9. Co-incubation of monocytes with LDL(-) and SDX for 24 h significantly reduced both the release of MMP-9 and TIMP-1 and gelatinase activity. In THP1 cells not expressing CD14, no effect of LDL(-) on MMP-9 or TIMP-1 release was observed. The uptake of DiI-labeled LDL(-) was higher than that of DiI-LDL(+) in THP1-CD14 but not in THP1 cells. This increase was inhibited by SDX. Experiments in microtiter wells coated with SDX demonstrated a specific interaction of LDL(-) with SDX.

CONCLUSIONS

LDL(-) induced the release of MMP-9 and TIMP-1 in monocytes through CD14. SDX affects the ability of LDL(-) to promote TIMP-1 and MMP-9 release by its interaction with LDL(-).

Fine structural characterization of sulodexide

Sulodexide is a heparinoid which combines the properties of its components heparin and dermatan sulfate and is used not only for the prophylaxis and treatment of thromboembolic diseases but also for the treatment of diabetic nephropathy. Despite many clinical studies have been conducted to investigate its activity and safety, no data are available on the fine chemical characterization of its components. In this work, the in-depth investigation on the structural features of both the whole mixture and the isolated components was accomplished, involving the analysis of molecular weight distribution and of their mono, di and oligosaccharide composition by HP-SEC/TDA, 2D-NMR and HPLC-MS techniques. Moreover, also the separation of fractions endowed of graded affinity to antithrombin was achieved followed again by detailed structural analysis. The combination of different techniques permits to profile in depth the structural features of such a drug and offers a useful tool for possible analysis of batch production.

Treatment of 5/6 nephrectomy rats with sulodexide: a novel therapy for chronic renal failure

AIM

Sulodexide, a glycosaminoglycan, could reduce albuminuria in diabetic patients. The aim of this study was to determine whether sulodexide could be used to treat chronic kidney failure in rats.

METHODS

Sixty Wistar rats undergone 5/6 nephrectomy, then were randomly divided into 4 groups: the model group, sulodexide group (sulodexide 5 mg/kg per day, im), irbesartan group irbesartan (20 mg/kg per day, ig) and sulodexide plus irbesartan group. Another 12 rats were enrolled into the sham operation group. After the treatments for 4, 8 and 12 weeks, urinary protein and serum creatinine levels were measured. After 12 weeks, serum cholesterin and triglycerides levels were measured, and the degrees of glomerular sclerosis and renal tubulointerstitial fibrosis were scored. The expression of aminopeptidase P (JG-12) in the renal tissue was examined using immunohistochemical staining. The renal expressions of endothelial nitric oxide synthase (eNOS) and tissue type plasminogen activator (tPA) were detected with RT-PCR and Western blot.

RESULTS

Proteinuria was markedly attenuated in the sulodexide-treated groups. After 4 and 8 weeks only the sulodexide-treated groups showed significant reduction in serum creatinine; while after 12 weeks all the three treatment groups showed significant reduction in serum creatinine. Furthermore, all the three treatment groups showed significant reduction in the scores of glomerular sclerosis and tubulointerstitial fibrosis. The glomerular expression of JG-12 was increased in both the sulodexide group and the sulodexide plus irbesartan group, but not in the irbesartan group. The eNOS mRNA and protein expression was decreased and the tPA mRNA and protein expression was significantly increased in the model group compared with Sham group. Sulodexide, irbesartan, and their combination reversed the decrease of eNOS expression but increased the tPA expression much more compared with model group.

CONCLUSION

Sulodexide was similar to irbesartan that can decrease proteinuria and attenuate renal lesions in 5/6 nephrectomy rats. The renal protection by sulodexide might be achieved via its impact on renal vascular endothelial cells.

Sulodexide ameliorates early but not late kidney disease in models of radiation nephropathy and diabetic nephropathy

BACKGROUND

Sulodexide is a glycosaminoglycan with anticoagulant and antithrombotic activities. Although sulodexide reduced albuminuria in patients with type 1 and type 2 diabetes, long-term effects on chronic renal injury are not established. We investigated sulodexide effects and mechanisms in a rat radiation nephropathy model and in the db/db mouse model of diabetic kidney disease.

METHODS

Sprague-Dawley rats received kidney radiation and were treated as follows: 15 mg/kg/day sulodexide s.c., 6 day/week (SUL) or no treatment (CONT). Subsets of animals were sacrificed after 8 weeks and 12 weeks. Blood pressure, serum creatinine, creatinine clearance (CrCl) and urinary protein excretion were measured every 4 weeks. Sclerosis and plasminogen activator inhibitor-1 (PAI-1) expression were assessed at 8 and 12 weeks, and collagen I, total collagen content and phospho-smad-2 expressions were determined at 12 weeks. Twelve-week-old db/db mice received sulodexide as above or vehicle. Albuminuria and CrCl were assessed at intervals till sacrifice at week 9 with assessment of urinary transforming growth factor-beta (TGF-beta) and glomerular lesions.

RESULTS

Blood pressure, serum creatinine and CrCl were not different in radiation rat CONT vs SUL at any time. Proteinuria was significantly lower in SUL compared to CONT at 4 and 8 weeks but not at 12 weeks. Sclerosis and PAI-1 expression trended lower in SUL vs CONT at 8 weeks. There was no difference between the groups in sclerosis, collagen I mRNA, total collagen content or PAI-1 expression at 12 weeks. Phospho-smad 2 expression was significantly decreased in SUL compared to CONT at 12 weeks. Db/db mice with or without SUL showed no difference in urinary albumin/creatinine ratio, urine TGF-beta or mesangial matrix expansion.

CONCLUSIONS

Our data show that sulodexide can reduce the early, but not late, proteinuria in radiation nephropathy in rats. In addition, sulodexide did not affect urine TGF-beta established albuminuria or mesangial matrix expansion in a chronic model of diabetic kidney disease in mice. Although sulodexide may affect TGF-beta activation in radiation nephropathy, this effect appeared insufficient in this model to inhibit the expressions of PAI-1 and collagen and reduce accumulation of extracellular matrix. These results may explain in part its lack of efficacy in recent clinical trials of chronic kidney disease.

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.

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.

Mesoglycan and sulodexide act as stabilizers and protectors of fibroblast growth factors (FGFs)

Heparin and heparan sulfate proteoglycans (HSPGs) stabilize FGFs which belong to heparin-binding growth factors (HBGFs) on active conformation. They also strongly potentiate their mitogenic activity on many cell types, and protect them against thermal denaturation and enzymatic degradation. In the present work we have tested two heparin-like substances named mesoglycan and sulodexide obtained from bovine intestinal mucosal extracts. These products are used as heparin, in various of therapeutic fields such as atherosclerosis or antithrombotic therapy. The compositions of mesoglycan and sulodexide are partially known and include chondroitin, dermatan and heparan sulfate. We have shown that mesoglycan and sulodexide potentiated the mitogenic activity of FGF1 and FGF2. The magnitude of this effect was identical with that of heparin used as a control substance but at double concentration. Mesoglycan and sulodexide also exerted stabilizing and protective effects on FGFs for heat denaturation and enzymatic degradation. The suppression of the protective properties after heparinase treatment of mesoglycan and sulodexide indirectly demonstrated the presence of heparan sulfate which was shown to represent about 60% of the commercial products.

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.

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.

Lowering of plasma viscosity by the oral administration of the glycosaminoglycan sulodexide in patients with peripheral vascular disease

The aim of the double-blind, crossover, placebo-controlled study was to evaluate whether oral administration of sulodexide, a medium molecular weight glycosaminoglycan, had an effect on whole blood, plasma and serum viscosity, and/or plasma fibrinogen concentrations. The drug was administered orally at a dose of 500 lipoproteinlipase releasing units twice daily for 1 month to two groups of 20 patients with peripheral vascular disease; one group was administered a placebo--drug sequence and the other a drug--placebo sequence. Orally administered sulodexide had a marked effect on plasma viscosity and on plasma fibrinogen concentrations, whereas there were no effects on whole blood viscosity. No significant side-effects were observed. The fact that sulodexide was highly effective, even after oral administration, suggests it may be useful for the treatment of patients with atheromatous vascular diseases of the lower limbs requiring chronic therapy.

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.

Effects of the oral administration of glycosaminoglycans on cellular abnormalities associated with idiopathic calcium oxalate nephrolithiasis

Oral administration of mixture of extractive glycosaminoglycans to a group of renal stone formers led to a significant decrease in oxalate self-exchange and in erythrocytes membrane protein phosphorylation traits that are abnormal in the majority of patients with idiopathic calcium nephrolithiasis. The action of glycosaminoglycans at the cellular level is probably due to their modulating activity on certain membrane protein kinases. The proven effect of the glycosaminoglycans opens a new pharmacological approach to the prevention of recurrent nephrolithiasis.

Effect of sulodexide on blood viscosity in patients with peripheral vascular disease

Thirty patients with Stage II peripheral vascular disease were treated with sulodexide, a new, medium molecular weight glycosaminoglycan, and placebo using a double-blind, crossover study design. After a 1-month wash-out period, patients were treated for 1 month with one or other trial medication and then crossed over to the alternative preparation for a further month. Measurements were made at baseline and at the end of each treatment period of serum, plasma and whole blood viscosities (at various shear rates), fibrinogen levels and red cell filterability. Tolerance parameters were also assessed at the same times. The results showed that there were statistically significant reductions in plasma and whole blood viscosity and in fibrinogen levels after sulodexide, but not after placebo. Neither treatment had any marked effect on red blood cell filterability. Local and systemic tolerance of the treatment was excellent, and some patients reported an improvement in symptoms whilst they were taking sulodexide; this, however, could not be quantified in this study. It is suggested that the viscosity and fibrinogen reducing effect of sulodexide make it a useful form of treatment in patients with atheromatous vascular diseases of the lower limbs.

Double-blind multicenter trial on a new medium molecular weight glycosaminoglycan. Current therapeutic effects and perspectives for clinical use

The ability of glycosaminoglycans to bind to a wide number of biologically active macromolecules has already been investigated. Recent clinical trials on the possible therapeutic benefits of glycosaminoglycans must be placed in perspective, even if they appear to be particularly encouraging, especially as regards the glycosaminoglycan effects on certain coagulation factors. A multicenter, medium-term, double-blind, crossover trial was performed by several Italian Lipid Clinics to determine whether administration of a medium molecular weight glycosaminoglycan (Sulodexide) has a significant clinical effect. Patients affected by peripheral vascular disease and/or hyperlipidemia (type IIa, IIb and IV) were submitted to a 4-week wash-out period, followed by parenteral Sulodexide (S) or placebo (P) administration for 2 weeks, another 2 week wash-out period, parenteral crossover drug or P administration for 2 weeks and, finally, oral S administration for 6 months. Sulodexide lowered plasma viscosity and plasma fibrinogen in all patients. There was also a drop in triglycerides together with a rise in apo A-I and HDL-C in type IV hyperlipoproteinemics, whereas there was no significant effect on total or LDL-plasma cholesterol in type IIa and IIb patients. Moreover, there was a percent increase in peak flow and rest flow in the lower limbs of peripheral vascular disease patients. No side effects or intolerance phenomena were detected. The results indicate that Sulodexide administration may be useful in long-term treatment of patients with peripheral vascular disease and a concomitant increase in plasma triglycerides and/or fibrinogen and/or viscosity.