Unique Extracellular Matrix Heparan Sulfate from the Bivalve Nodipecten nodosus (Linnaeus, 1758) Safely Inhibits Arterial Thrombosis after Photochemically Induced Endothelial Lesion*

Heparin-like glycans with diverse disaccharide composition and high anticoagulant activity have been described in several families of marine mollusks. The present work focused on the structural characterization of a new heparan sulfate (HS)-like polymer isolated from the mollusk Nodipecten nodosus (Linnaeus, 1758) and on its anticoagulant and antithrombotic properties. Total glycans were extracted from the mollusk and fractionated by ethanol precipitation. The main component (>90%) was identified as HS-like glycosaminoglycan, representing ∼4.6 mg g−1 of dry tissue. The mollusk HS resists degradation with heparinase I but is cleaved by nitrous acid. Analysis of the mollusk glycan by one-dimensional 1H, two-dimensional correlated spectroscopy, and heteronuclear single quantum coherence nuclear magnetic resonance revealed characteristic signals of glucuronic acid and glucosamine residues. Signals corresponding to anomeric protons of nonsulfated, 3- or 2-sulfated glucuronic acid as well as N-sulfated and/or 6-sulfated glucosamine were also observed. The mollusk HS has an anticoagulant activity of 36 IU mg−1, 5-fold lower than porcine heparin (180 IU mg−1), as measured by the activated partial thromboplastin time assay. It also inhibits factor Xa (IC50 = 0.835 μg ml−1) and thrombin (IC50 = 9.3 μg ml−1) in the presence of antithrombin. In vivo assays demonstrated that at the dose of 1 mg kg−1, the mollusk HS inhibited thrombus growth in photochemically injured arteries. No bleeding effect, factor XIIa-mediated kallikrein activity, or toxic effect on fibroblast cells was induced by the invertebrate HS at the antithrombotic dose

Unfractionated Heparin and New Heparin Analogues from Ascidians (Chordate-Tunicate) Ameliorate Colitis in Rats*

The anti-inflammatory effect of mammalian heparin analogues, named dermatan sulfate and heparin, isolated from the ascidian Styela plicata was accessed in a TNBS-induced colitis model in rats. Subcutaneous administration of the invertebrate compounds during a 7-day period drastically reduced inflammation as observed by the normalization of the macroscopic and histological characteristics of the colon. At the molecular level, a decrease in the production of TNF-α, TGF-β, and VEGF was observed, as well as a reduction of NF-κB and MAPK kinase activation. At the cellular level, the heparin analogues attenuated lymphocyte and macrophage recruitment and epithelial cell apoptosis. A drastic reduction in collagen-mediated fibrosis was also observed. No hemorrhagic events were observed after glycan treatment. These results strongly indicate the potential therapeutic use of these compounds for the treatment of colonic inflammation with a lower risk of hemorrhage when compared with mammalian heparin