heparitin-sulfate and Necrosis

Cobra venom contains cardiotoxins (CTXs) that induce tissue necrosis and systolic heart arrest in bitten victims. CTX-induced membrane pore formation is one of the major mechanisms responsible for the venom's designated cytotoxicity. This chapter examines how glycoconjugates such as heparan sulfates (HS) and glycosphingolipids, located respectively in the extracellular matrix and lipid bilayers of the cell membranes, facilitate CTX pore formation. Evidences for HS-facilitated cell surface retention and glycosphingolipid-facilitated membrane bilayer insertion of CTX are reviewed. We suggest that similar physical steps could play a role in the mediation of other pore forming toxins (PFT). The membrane pores formed by PFT are expected to have limited lifetime on biological cell surface as a result of membrane dynamics during endocytosis and/or rearrangement of lipid rafts.

Topics: Animals; Cobra Cardiotoxin Proteins; Elapidae; Heart Arrest; Heparitin Sulfate; Humans; Lipid Bilayers; Membrane Microdomains; Necrosis; Pore Forming Cytotoxic Proteins; Sphingolipids

Recommendations for transitioning from therapy with heparin or a low-molecular-weight heparin preparation to therapy with an oral anticoagulant in patients with acute venous or arterial thromboembolism have undergone several changes during the last two decades. Physicians are now comfortable with beginning treatment with an oral anticoagulant once the diagnosis is confirmed, and loading doses are no longer considered to be necessary. Exceptions to early transition may be necessary in patients with an extensive iliofemoral or axillary-subclavian vein thrombosis or pulmonary embolism where thrombolytic agents may be indicated, or in individuals who require surgery or other invasive procedures, or if there are concerns about bleeding. The avoidance of early transition to oral anticoagulants in patients with acute heparin-induced thrombocytopenia also has been advised because of the potential for further thrombotic complications, including venous limb gangrene and warfarin-induced skin necrosis.

Topics: Administration, Oral; Anticoagulants; Arginine; Blood Coagulation; Blood Coagulation Factors; Chondroitin Sulfates; Dermatan Sulfate; Drug Combinations; Gangrene; Heparin; Heparitin Sulfate; Hirudins; Humans; Ischemia; Leg; Necrosis; Pipecolic Acids; Recombinant Proteins; Skin; Sulfonamides; Thrombocytopenia; Thrombosis; Warfarin

There are three distinct syndromes of heparin-induced thrombocytopenia: an acute reversible from seen immediately after intravenous bolus injection, a delayed-onset antibody-mediated form seen several days after the initiation of therapy, and an intermediate type characterized by mild thrombocytopenia developing just a few days after starting therapy. Delayed-onset heparin-induced thrombocytopenia, clinically the most important form, results from the formation of heparin-dependent antibodies that are directed against the platelet membrane. In the presence of heparin, these antibodies may induce in vitro or in vivo platelet aggregation. Consequently, the course may be complicated by arterial thromboses. Treatment of this syndrome includes the prompt cessation of heparin. Since continued or future anticoagulation is usually necessary, alternative means of anticoagulation have been explored. Oral anticoagulation is often started but requires several days to take effect. Other options include low-molecular-weight heparins, antiplatelet agents, prostacyclin analogues, and low-molecular-weight dextran. In vitro laboratory tests may be helpful in guiding alternative therapy in some, but not all cases. Unfortunately, none of these agents have proved to be uniformly effective and additional agents and clinical investigation are needed before a definitive option becomes available.

Topics: Aspirin; Cardiopulmonary Bypass; Chondroitin Sulfates; Dermatan Sulfate; Epoprostenol; Fibrinolytic Agents; Glycosaminoglycans; Heparin; Heparinoids; Heparitin Sulfate; Humans; Iloprost; Necrosis; Platelet Aggregation Inhibitors; Skin; Skin Diseases; Thrombocytopenia; Thrombosis

Life-threatening cardiomyopathy is a severe, but common, complication associated with severe trauma or sepsis. Several signaling pathways involved in apoptosis and necroptosis are linked to trauma- or sepsis-associated cardiomyopathy. However, the underling causative factors are still debatable. Heparan sulfate (HS) fragments belong to the class of danger/damage-associated molecular patterns liberated from endothelial-bound proteoglycans by heparanase during tissue injury associated with trauma or sepsis. We hypothesized that HS induces apoptosis or necroptosis in murine cardiomyocytes. By using a novel Medical-

Topics: Algorithms; Animals; Apoptosis; Cardiomyopathies; Caspase 3; Cell Culture Techniques; Cells, Cultured; Cytochromes c; Heparitin Sulfate; Humans; Machine Learning; Mice; Myocytes, Cardiac; Necrosis; Receptor-Interacting Protein Serine-Threonine Kinases; Sepsis; Signal Transduction; Wounds and Injuries

Life-threatening heparin-induced thrombocytopenia (HIT) is treated with the alternative nonheparin anticoagulants argatroban, lepirudin, or danaparoid. Frequently, the pentasaccharide fondaparinux is used off-label.. The authors sought to investigate the safety and efficacy of the different anticoagulants for treating HIT.. In a national, multicenter registry study, hospitalized patients who were diagnosed with HIT, an at least intermediate clinical HIT-risk (4Ts score ≥4 points), and received treatment with ≥1 dose of the aforementioned anticoagulants were included. Main outcome measures were the incidences of HIT-specific complications (thromboembolic venous/arterial events, amputations, recurrent/persistent thrombocytopenia, skin lesions) and bleedings.. Of 195 patients, 46 (23.6%), 4 (2.1%), 61 (31.3%), and 84 (43.1%) had been treated first-line with argatroban, lepirudin, danaparoid, and fondaparinux, respectively. The composite endpoint of HIT-specific complications (thromboembolic events, amputation, skin necrosis) occurred in 11.7% of patients treated with approved alternative anticoagulation and in 0.0% of fondaparinux-treated patients. The all-cause in-hospital mortality rates were 14.4% during approved alternative anticoagulation and 0.0% during fondaparinux treatment. Bleeding complications occurred in alternatively anticoagulated patients and in fondaparinux-treated patients in 6.3% and 4.8%, respectively. Post hoc analysis of clinical and laboratory features confirmed "true" HIT in at least 74 of 195 (38.0%) patients; 35 of 74 (47.3%) were treated with fondaparinux.. Fondaparinux is effective and safe in suspected acute HIT; no HIT-specific complications occurred in the fondaparinux-treated patients, even among those with a high clinical HIT probability. Further data from randomized controlled trials are urgently needed because lepirudin was recalled from the market; danaparoid access has been limited and is not approved in the United States; and argatroban is contraindicated in patients with impaired liver function, and activated partial thromboplastin time confounding may interfere with monitoring. (Retrospective Registry of Patients With Acute Heparin-induced Thrombocytopenia Type II; NCT01304238).

Topics: Anticoagulants; Arginine; Chondroitin Sulfates; Dermatan Sulfate; Factor Xa Inhibitors; Female; Fondaparinux; Hemorrhage; Heparin; Heparitin Sulfate; Hirudins; Hospital Mortality; Hospitalization; Humans; Male; Necrosis; Off-Label Use; Partial Thromboplastin Time; Patient Safety; Pipecolic Acids; Polysaccharides; Recombinant Proteins; Registries; Retrospective Studies; Sulfonamides; Thrombocytopenia; Thromboembolism; Treatment Outcome

Dying cells, such as apoptotic and necrotic cells, are cleared rapidly from the site of cell death to prevent the exposure of intracellular antigenic and immunostimulatory molecules that may cause tissue injury or facilitate the development of autoimmune diseases. For the immune system to recognize and remove dying cells efficiently, professional phagocytes use a variety of mechanisms that distinguish healthy cells from dying cells. HRG, a relatively abundant heparin/HS-binding protein in human plasma, has been shown recently to tether IgG specifically to necrotic cells and aid the phagocytic uptake of necrotic cells via a FcgammaRI-dependent pathway. In this study, we provide direct evidence that HRG can function cooperatively with cell surface HS on the monocytic cell line THP-1 to promote necrotic cell removal. In addition, we found that the presence of heparin can markedly inhibit HRG-enhanced necrotic cell clearance by THP-1 cells, possibly by blocking the ability of HRG to interact with necrotic cells as well as THP-1 cells. Thus, these data suggest that HRG can aid the phagocytosis of necrotic cells via a HS-dependent pathway, and this process can be regulated by the presence of certain HRG ligands, such as heparin.

Topics: Animals; Cell Communication; Cell Line; Cell Membrane; Cell Survival; Chondroitin Sulfates; Dermatan Sulfate; Hemin; Heparin; Heparitin Sulfate; Humans; Models, Immunological; Necrosis; Phagocytes; Phagocytosis; Protein Binding; Proteins; T-Lymphocytes; Zinc

Mucopolysaccharidosis type IIIA is a neurodegenerative lysosomal storage disorder characterized by progressive loss of learned skills, sleep disturbance and behavioural problems. Absent or greatly reduced activity of sulphamidase, a lysosomal protein, results in intracellular accumulation of heparan sulphate. Subsequent neuroinflammation and neurodegeneration typify this and many other lysosomal storage disorders. We propose that intra-cerebrospinal fluid protein delivery represents a potential therapeutic avenue for treatment of this and other neurodegenerative conditions; however, technical restraints restrict examination of its use prior to adulthood in mice. We have used a naturally-occurring Mucopolysaccharidosis type IIIA mouse model to determine the effectiveness of combining intravenous protein replacement (1 mg/kg) from birth to 6 weeks of age with intra-cerebrospinal fluid sulphamidase delivery (100 microg, fortnightly from 6 weeks) on behaviour, the level of heparan sulphate-oligosaccharide storage and other neuropathology. Mice receiving combination treatment exhibited similar clinical improvement and reduction in heparan sulphate storage to those only receiving intra-cerebrospinal fluid enzyme. Reductions in micro- and astrogliosis and delayed development of ubiquitin-positive lesions were seen in both groups. A third group of intravenous-only treated mice did not exhibit clinical or neuropathological improvements. Intra-cerebrospinal fluid injection of sulphamidase effectively, but dose-dependently, treats neurological pathology in Mucopolysaccharidosis type IIIA, even when treatment begins in mice with established disease.

Topics: Analysis of Variance; Animals; Antibodies; Body Weight; Brain; Chromatography, High Pressure Liquid; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Routes; Exploratory Behavior; Heparitin Sulfate; Hydrolases; Lysosomal Storage Diseases; Male; Maze Learning; Mice; Mice, Inbred C57BL; Mice, Knockout; Mucopolysaccharidosis III; Necrosis; Proteins; Tandem Mass Spectrometry; Time Factors

A beta1-40 and perlecan (A beta + perlecan) were infused into rat hippocampus for 1 week via osmotic pumps. At the end of the infusion a deposit of A beta immunoreactive material was found surrounding the infusion site. No neurons could be identified within this A beta deposit. The neuron-free area resulting from A beta + perlecan was significantly larger than that found after infusions of A beta40-1 and perlecan (reverse A beta + perlecan), perlecan alone or phosphate-buffered saline vehicle. Following infusion of A beta + perlecan, the glial cells segregated in a manner similar to that associated with compacted amyloid plaques in Alzheimer's disease (AD). Activated microglia/macrophages were prevalent within the A beta deposit while the perimeter of the deposit was delimited by reactive astrocytes. Thioflavin S and Congo red staining indicated a beta-pleated sheet conformation of the A beta deposits, implying formation of fibrils. Intact, apparently healthy neurons were found immediately adjacent to the A beta + perlecan deposit. In contrast, reverse A beta peptide did not form congophilic deposits despite the presence of perlecan. Apoptotic profiles visualized with bisbenzamide or TUNEL staining of fragmented DNA were not seen at any of the infusion sites, yet were readily seen in hippocampal sections from animals treated with kainic acid. At 8 weeks, A beta immunoreactivity, Thioflavin S and Congo red staining was reduced, indicating that A beta was being cleared. There also was no evidence of neuron loss by Nissl or TUNEL staining. The zone of apparent necrosis did not expand between 1 and 8 weeks, and in some instances appeared to contract. The consistency of the A beta + perlecan infusion method in producing reliable A beta amyloid deposits permits estimates of the rate at which fibrillar A beta amyloid can be removed from the brain, and may provide a useful model to study this process in vivo. However, the absence of clearly identifiable degenerating/dying neurons at the 1 or 8 week survival times suggests that either fibrillar A beta + perlecan slowly displaced the brain parenchyma during infusion, or neurons were killed very gradually during the process of clearing the A beta.

Topics: Amyloid beta-Peptides; Animals; Brain; Heparan Sulfate Proteoglycans; Heparitin Sulfate; Immunohistochemistry; Male; Necrosis; Neuroglia; Neurotoxins; Peptide Fragments; Proteoglycans; Rats; Rats, Sprague-Dawley; Time Factors; Tissue Distribution

Loxoscelism or necrotic arachnidism are terms used to describe lesions and reactions induced by bites (envenomation) from spiders of the genus Loxosceles. Envenomation has been reported to provoke dermonecrosis and haemorrhage at the bite site and haemolysis, disseminated intravascular coagulation and renal failure. The purpose of this work was to study the effect of the venom of the brown spider Loxosceles intermedia on basement membrane structures and on its major constituent molecules. Light microscopy observations showed that L. intermedia venom obtained through electric shock, which reproduces two major signals of Loxoscelism in the laboratory, exhibits activity toward basement membrane structures in mouse Engelbreth-Holm-Swarm (EHS) sarcoma. Basement degradation was seen by a reduced periodic acid-Schiff (PAS) and alcian blue staining as well as by a reduced immunostaining for laminin when compared to control experiments. Electron microscopy studies confirmed the above results, showing the action of the venom on EHS-basement membranes and demonstrating that these tissue structures are susceptible to the venom. Using purified components of the basement membrane, we determined through SDS-PAGE and agarose gel that the venom is not active toward laminin or type IV collagen, but is capable of cleaving entactin and endothelial heparan sulphate proteoglycan. In addition, when EHS tissue was incubated with venom we detected a release of laminin into the supernatant, corroborating the occurrence of some basement membrane disruption. The venom-degrading effect on entactin was blocked by 1, 10-phenanthroline, but not by other protease inhibitors such as PMSF, NEM or pepstatin-A. By using light microscopy associated with PAS staining we were able to identify that 1,10-phenanthroline also inhibits EHS-basement membrane disruption evoked by venom, corroborating that a metalloprotease of venom is involved in these effects. Degradation of these extracellular matrix molecules and the observed susceptibility of the basement membrane could lead to loss of vessel and glomerular integrity, resulting in haemorrhage and renal problems after envenomation.

Topics: Animals; Basement Membrane; Electrophoresis, Polyacrylamide Gel; Heparitin Sulfate; Humans; Immunohistochemistry; Membrane Glycoproteins; Microscopy, Electron; Microscopy, Electron, Scanning; Necrosis; Neoplasm Transplantation; Phosphoric Diester Hydrolases; Platelet Aggregation; Protease Inhibitors; Proteoglycans; Rabbits; Sarcoma, Experimental; Serine Endopeptidases; Skin; Spider Venoms

A 52-year-old man had been in terminal renal failure for 6 years. On haemodialysis under heparin without complications, acral skin necroses occurred. Even with low-molecular heparin anticoagulation further lesions developed. Within 12 weeks of haemodialysis being performed without heparin the necroses healed, but they recurred when heparin was again added for dialysis. On admission the patient was in poor general condition, with a weight of 55 kg (height 175 cm). LABORATORY INVESTIGATIONS: The heparin-induced platelet aggregation (HIPA) test was positive in the absence of thrombocytopenia. Na-heparin reacted positively in three out of four tests, but Danaparoid did not react.. The skin necroses once again healed after the heparinoid Danaparoid, which had not reacted in the HIPA test, had been substituted for heparin.. This case illustrates that skin necroses, thrombocytopenia and thromboembolism can be independent signs of immunologically induced platelet aggregation.

Topics: Anticoagulants; Chondroitin Sulfates; Dermatan Sulfate; Drug Combinations; Foot Dermatoses; Heparin; Heparinoids; Heparitin Sulfate; Humans; Kidney Failure, Chronic; Male; Middle Aged; Necrosis; Platelet Aggregation; Renal Dialysis; Skin; Skin Diseases