Federal University of Rio de Janeiro, Brazil
Title: Galactanomics: Marine glycans with differential actions in coagulation and thrombosis
Vitor H. Pomin, Adjunt Professor at the Institute of Medical Biochemistry (IBqM) in Federal University of Rio de Janeiro since 2011, conducts research on glycobiology, NMR spectroscopy, and biomedical uses of marine carbohydrates. He is author of 9 book chapters, main editor of 3 books, and has over 20 peer-reviewed published articles, besides serving as editorial board member and reviewer of innumerous reputed journals. After obtaining his Ph.D. in Biological Chemistry (2008) at IBqM, he had a 3-year post-doctoral experience at Complex Carbohydrate Research Center, UGA, USA.
Glycomics is a current international project interested in the comprehensive analysis of carbohydrates, not only physiologically active but also medically relevant. Galactanomics is a subdivision of this project whose target glycans are named galactans (galactose-composing sugars). Th ey are basically of marine origin and highly sulfated. Th is latter feature enables molecular interactions with cationic proteins such as those involved in the coagulation system. Sulfated galactans (SGs) from marine organisms may exhibit diff erential chemical structures which allow advanced structure-function relationship studies, especially those of benefi cial eff ects in hemostasis. In this work, SGs isolated from two species of red alga were comparatively examined with regard to their structures and functions in anticoagulation, antithrombosis and bleeding. In comparison with heparin, a potent anticoagulant and antithrombotic agent with extensive bleeding side-eff ects, the SG from Botryocladia occidentalis was also highly anticoagulant and antithrombotic in the venous models (just in lower doses), aside from showing no additional bleeding eff ect. Th is algal SG is composed of a simple disaccharide repeating unit with heterogeneous sulfation distribution. Conversely, the structurally complex and heterogeneous SG from Acanthophora muscoides exhibited a signifi cant antithrombotic eff ect only on the arterial model, even showing no anticoagulant action and no bleeding eff ect. Unlike heparin, both red algal SGs have shown a serpin-independent anticoagulant mechanism. Th is work clearly dissociate the biochemical mechanisms involved in anticoagulation, arterial and venous antithrombosis, and bleeding, and suggests that the mechanisms of action of novel therapeutic agents in controlling the blood clot might include serpin-unrelated pathways.
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