Interaction between glycosaminoglycans, platelets, and leukocytes

Effects of different routes of administration and doses of Sulodexide on leukocyte-endothelium interaction and tissue perfusion on an animal model of low flow and high pressure in veins

Objectives

To assess the effects of different doses and routes of Sulodexide on leukocyte-endothelium interaction and tissue perfusion in a model of venous hypertension and low blood flow.

Methods

Six weeks after venous hypertension induction, through external iliac vein ligature male hamsters ( Mesocricetus auratus) received Sulodexide at 1, 2, or 4 mg/kg/day or saline (placebo) by subcutaneous or intramuscular routes during 2 or 4 weeks. After treatments, leukocyte rolling and adhesion, functional capillary density (FCD), and venular diameter were evaluated on the affected hindlimb.

Results

Subcutaneous and intramuscular treatments with Sulodexide after 2 and 4 weeks, significantly reduced leukocyte rolling and adhesion and increased FCD. Sulodexide did not affect venular diameter and intramuscular treatment was more effective in reducing leukocyte adhesion than the subcutaneous one.

Conclusion

This preliminary study demonstrated that Sulodexide significantly decreased leukocyte-endothelium interaction and improved tissue perfusion in hamsters subjected to venous hypertension and low blood flow.

Sulodexide in venous disease

Sulodexide is a glycosaminoglycan extracted from porcine intestinal mucosa. The purpose of this review is to discuss sulodexide's complex pharmacological profile and its clinical applications for venous disease. Sulodexide has wide-ranging biological effects on the vascular system, including antithrombotic, profibrinolytic, anti-inflammatory, endothelial protective and vasoregulatory effects. Sulodexide has emerged as a potential therapeutic option for the management of chronic venous insufficiency, including venous ulceration, and the prevention of recurrent venous thromboembolism, with a low rate of major bleeding complications. Sulodexide's pleiotropic vascular effects may facilitate the management of common venous 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.

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.

Pathogenic factors in vascular dementia and Alzheimer's disease. Multiple actions of heparin that probably are beneficial

The following areas are discussed in this review: atherogenesis; cerebrovascular factors; hypoperfusion; beta-amyloid production; beta-amyloid fibril formation; beta-sheets; metal cations; reactive oxygen species/free radicals; chronic inflammatory factors; endogenous plasma heparin; lipoprotein lipase; polyamines; protein kinase C; casein kinases; phospholipase A2; serine proteases; myeloperoxidase; cyclooxygenase 2; cysteine proteases; caspases; proprotein convertases; aspartic proteases; cyclin proteinases; thrombin; tau hyperphosphorylation; advanced glycosylation end products; activator protein 1; calcium; apolipoprotein E epsilon4; histamine; blood-brain barrier; glutamate; transglutaminase; insulin-like growth factor 1.

Sulodexide attenuates myocardial ischemia/reperfusion injury and the deposition of C-reactive protein in areas of infarction without affecting hemostasis

Several glycosaminoglycans (GAGs) have been demonstrated to protect the ischemic heart against reperfusion injury, in part, by modulating activation of the complement cascade. The present study assessed the cardioprotective effects of sulodexide (KRX-101), a mixture of GAGs composed of 80% low-molecular mass heparin and 20% dermatan sulfate. KRX-101 differs from other GAGs (e.g., heparin) in that it has limited anticoagulant efficacy and can be administered orally. The experimental protocol was designed to determine whether KRX-101 could protect the ischemic myocardium. Anesthetized New Zealand white rabbits underwent 30 min of coronary artery occlusion. Intravenous doses of KRX-101 (0.5 mg/kg, n = 10) or drug diluent (n = 10) were administered at the end of regional ischemia and at each hour of reperfusion. Infarct size, as a percentage of the area at risk, was calculated for both groups. Myocardial infarct size was 31.3 +/- 4.1% in the vehicle- and 17.3 +/- 3.2% in the KRX-101-treated animals (p < 0.05 versus vehicle). Activated partial thromboplastin times determined at baseline (preischemia) and at each hour of reperfusion (n = 4) were not significantly different between vehicle- and KRX-101-treated groups (p = N.S.). Myocardial injury was further assessed by measuring serum levels of cardiac-specific troponin I. KRX-101 administration significantly reduced (p < 0.05) the serum concentration of troponin I during reperfusion. The results suggest that KRX-101 may be an effective adjunctive agent in myocardial revascularization procedures, without the risk of increased bleeding.

Oral erosive/ulcerative lichen planus: preliminary findings in an open trial of sulodexide compared with cyclosporine (ciclosporin) therapy

OBJECTIVE

To study the effect of the heparinoid sulodexide systemically, compared with topical cyclosporine (ciclosporin), on chronic oral erosive/ulcerative lichen planus.

STUDY DESIGN

An open nonrandomized trial was conducted in two groups of 10 Italian patients with lichen planus, with subjective assessment of pain and assessment of ulceration amelioration by nonblinded clinicians.

RESULTS

Comparable pain relief and amelioration of erosions/ulcers were seen in patients on sulodexide and in those on ciclosporin, but with faster healing in those on sulodexide.

CONCLUSIONS

Sulodexide appears to be as effective, and perhaps more effective, than topical ciclosporin in the therapy of oral lichen planus, and is less expensive, but full double-blind placebo-controlled studies are required.

Treatment of concanavalin A-induced hepatitis in mice with low molecular weight heparin

BACKGROUND/AIMS

Heparin has been noted to inhibit inflammation independent of its known anti-coagulant activity. In the present study, we examined the ability of heparin and low molecular weight heparin to prevent immune-mediated, concanavalin A-induced liver damage.

METHODS

Mice were pretreated with either heparin or low molecular weight heparin (Fragmin) prior to their inoculation with concanavalin A (10 mg/kg). Liver enzymes, liver histology, and the serum levels of tumor necrosis factor-a, interleukin-6, and interleukin-10 were examined in the control and treated mice.

RESULTS

The histopathologic damage in the liver, and the concanavalin A-induced release of aminotransferases, tumor necrosis factor-a, and interleukin-6 were significantly inhibited in mice pretreated with low molecular weight heparin, whereas the serum levels of the anti-inflammatory cytokine interleukin-10 were increased (p<0.01). Interestingly, maximal inhibition was obtained with low low molecular weight heparin doses (5 and 1 microg/mouse, p<0.001), while higher doses were less effective. Concanavalin A-induced liver injury was not prevented by pretreatment of the mice with heparan sulphate (p<0.001), which although it is structurally similar to heparin possesses neither anti-inflammatory nor anti-coagulant properties.

CONCLUSIONS

This study demonstrates the efficacy of low molecular weight heparin in preventing immune-mediated liver damage in mice.

Heparin in inflammation: potential therapeutic applications beyond anticoagulation

In this chapter we have described anti-inflammatory functions of heparin distinct from its traditional anticoagulant activity. We have presented in vivo data showing heparin's beneficial effects in various preclinical models of inflammatory disease as well as discussed some clinical studies showing that the anti-inflammatory activities of heparin may translate into therapeutic uses. In vivo models that use low-anticoagulant heparins indicate that the anticoagulant activity can be distinguished from heparin's anti-inflammatory properties. In certain cases such as hypovolemic shock, the efficacy of a low-anticoagulant heparin derivative (GM1892) exceeds heparin. Data also suggest that nonconventional delivery of heparin, specifically via inhalation, has therapeutic potential in improving drug pharmacokinetics (as determined by measuring blood coagulation parameters) and in reducing the persistent concerns of systemic hemorrhagic complications. Results from larger clinical trials with heparin and LMW heparins are eagerly anticipated and will allow us to assess our predictions on the effectiveness of this drug class to treat a variety of human inflammatory diseases.

Heparin and low molecular weight heparin decrease nitric oxide production by human polymorphonuclear cells

BACKGROUND

Heparin and heparin derivatives with low anticoagulant activity exhibit a wide spectrum of biological functions affecting adhesion, activation and trafficking of leukocytes.

METHODS

We investigated the in vitro effect of heparin and a low molecular weight heparin derivative (LMWH) on nitric oxide (NO) production by human polymorphonuclear leukocytes (PMN).

RESULTS

N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated NO production was significantly decreased by heparin at doses of 0.5 and 5 micrograms/mL, while LMWH was only effective at doses of 50 and 200 micrograms/mL by means of a mechanism not related to NO synthase (NOS) activity.

CONCLUSIONS

These results support the hypothesis that heparin and LMWH derivatives may offer therapeutic benefit for inflammatory diseases where NO plays a protagonic role.

Heparin inhibits leukocyte rolling in pial vessels and attenuates inflammatory changes in a rat model of experimental bacterial meningitis

Heparin is a natural proteoglycan that was first described in 1916. In addition to its well characterized effect on blood coagulation, it is becoming clear that heparin also modulates inflammatory processes on several levels, including the interference with leukocyte-endothelium interaction. Anecdotal observations suggest a better clinical outcome of heparin-treated patients with bacterial meningitis. The authors demonstrate that heparin, a glycosaminoglycan, inhibits significantly in the early phase of experimental pneumococcal meningitis the increase of 1) regional cerebral blood flow (125 +/- 18 versus 247 +/- 42%), 2) intracranial pressure (4.5 +/- 2.0 versus 12.1 +/- 2.2 mm Hg), 3) brain edema (brain water content: 78.23 +/- 0.33 versus 79.49 +/- 0.46%), and 4) influx of leukocytes (571 +/- 397 versus 2400 +/- 875 cells/microL) to the cerebrospinal fluid compared with untreated rats. To elucidate the possible mechanism of this observation, the authors investigated for the first time leukocyte rolling in an inflammatory model in brain venules by confocal laser scanning microscopy in vivo. Heparin significantly attenuates leukocyte rolling at 2, 3, and 4 hours (2.8 +/- 1.3 versus 7.9 +/- 3.2/100 microm/min), as well as leukocyte sticking at 4 hours (2.1 +/- 0.4 versus 3.5 +/- 1.0/100 microm/min) after meningitis induction compared with untreated animals. The authors conclude that heparin can modulate acute central nervous system inflammation and, in particular, leukocyte-endothelium interaction, a key process in the cascade of injury in bacterial meningitis. They propose to evaluate further the potential of heparin in central nervous system inflammation in basic and clinical studies.

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.