Inhibition of rat glomerular visceral epithelial cell growth by heparin

The effect of several glycosaminoglycans and sulfated polysaccharides on the growth of cultured rat glomerular visceral epithelial cells (GEC) was studied in vitro. Heparin, one preparation of heparan sulfate proteoglycan, dextran sulfate, and pentosan polysulfate significantly inhibited the growth of several GEC clones studied (36.0-77.1% inhibition at 100 micrograms/ml). Other glycosaminoglycans studied did not affect GEC growth. Growth inhibition by heparin was dose related and did not appear to reflect cytotoxicity. Heparins with high or low affinity for antithrombin inhibited growth to similar degrees. When heparin was fractionated into high- and low-anticoagulant activity fractions by physicochemical means the high activity fraction displayed significantly greater growth inhibition. The degree of growth inhibition significantly correlated with serum concentration in the media (r = 0.64; P less than 0.001). Removal of heparin binding factors from serum resulted in a loss of this correlation as well as less overall growth inhibition. These experiments suggest that interactions of GEC with heparan sulfates and other heparin-like molecules in the extracellular matrix may be important in the control of GEC growth.