Abstract

Background: Fucoidan is a natural sulfated polysaccharide which exists mainly in the cell wall matrix of various species of brown seaweed. Various forms of fucoidan have also been recognized in some marine invertebrates such as sea urchins and sea cucumbers. Fucoidan inhibits the spread of cancerous cells by preventing the adhesion of tumor cells to the extracellular matrix in addition to inducing apoptosis, or programmed self-destruction, in human T-cells infected by T-cells leukemia virus type I (HTLV-1) which causes adult T-cell leukemia. The polysaccharide has also been shown to stimulate the phagocytic action of macrophages and synthesis of several immune cell types, which increases protection against infection. Fucoidan gives the immune system a big boost by enhancing phagocytosis. Additionally, it increases the number of mature white blood cells which are circulating in the body, thereby bolstering the first line of defense against infections and diseases. Moreover, fucoidan has anti-coagulant, anti-thrombotic, anti-inflammatory, antioxidant, anti-allergic, anti-tumor properties and also many others. Methods and Results: In this study, we investigated whether fucoidan is able to alleviate the vascular remodeling process triggered by immunological stimuli in rat allogenic aorta transplantation model, in addition to the evaluated potential mechanisms responsible for the observed effects. Our rat aorta transplantation model was subjected to intraperitoneal or oral treatment with fucoidan or placebo. The results of our study demonstrated that fucoidan inhibits endointimal hyperplasia formation and vascular modulation. In particular, intraperitoneal and oral administration of fucoidan reduced neointima formation in allografts retrieved 8 weeks after transplantation. Moreover, both treatments with fucoidan reduced the number of smooth muscle (SM) a-actin positive cells in intima and adventitia, decreased percentage of macrophages in intima and media, and increased the number of leukocytes in media of the allografts. Fucoidan treatments have also caused reduction in apoptosis in allograft intima and media. Conclusion: Through our study, we demonstrated the inhibitory effect of fucoidan on vascular remodeling in transplant vasculopathy within rats. Our study is the first report of the beneficial effects of fucoidan oral administration on this process, which may have important clinical implications and result in a better understanding of vascular remodeling.

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