Abstract
Heparan sulfate proteoglycans produced by vascular endothelium may function physiologically to restrain the migration, multiplication, and phenotypic transition of vascular smooth-muscle cells, and to maintain an anticoagulant luminal surface by bonding and activating antithrombin III. Thus, ample production of heparan sulfate proteoglycans may act to prevent atherosclerosis and its thrombotic complications. The ability of exogenous heparin to stimulate synthesis of heparan sulfate proteoglycans by vascular endothelium may be largely responsible for the positive outcomes of most controlled evaluations of low-dose heparin as a long-term therapy for coronary disease. Glucosamine, a biosynthetic precursor of mucopolysaccharides, can substantially enhance mucopolysaccharide production when added to cultured fibroblasts or chondrocytes; the clinical utility of oral glucosamine in osteoarthritis may reflect increased synthesis of cartilage proteoglycans. It is reasonable to speculate that exogenous glucosamine will likewise enhance heparan sulfate proteoglycans production by vascular endothelial cells, and, when administered orally in regimens comparable to those effective in osteoarthritis, will thereby act to retard atherogenesis.