The biological effects of depolymerized sodium spirulan and sulfated colominic acid on vascular cells are beneficial in preventing atherosclerosis

Abstract

Atherosclerosis is a vascular lesion that is a common health problem in advanced countries. Functional damage of the vascular endothelial cells, vascular smooth muscle cell hyperplasia, and procoagulant/antifibrinolytic state of blood are generally observed in the lesion. Since polysaccharides such as heparin modulate vascular cell behavior through interaction with cytokines/growth factors, we hypothesized that polysaccharides from natural sources may possess beneficial biological activities that prevent atherosclerosis. Changes in cultured aortic endothelial and smooth muscle cells were investigated after treatment with the polysaccharides sodium spirulan (Na-SP) - a sulfated polysaccharide obtained from a hot water extract of the blue-green alga Spirulina platensis - and colominic acid (CA)-prepared as a homopolymer of N-acetylneuraminic acid produced by Escherichia coli K1. The experiments suggest that depolymerized Na-SP and sulfated CA can function as precursors of the agents that prevent atherosclerosis. In particular, both the chemically modified polysaccharides significantly inhibit the proliferation of the arterial smooth muscle cells without exhibiting any toxic effects on the integrity of the vascular endothelial cell layers. The results also indicate that chemical modifications, for example, depolymerization of Na-SP and sulfation of CA, can control the biological effects of these polysaccharides on vascular cells.