Cadmium Stimulation of Glycosaminoglycan Synthesis by Cultured Vascular Endothelial Cells : Comparison of Various Cell Types

Abstract

We investigated the effect of cadmium on the synthesis of glycosaminoglycans (GAGs) in confluent cultures of vascular endothelial cells derived from bovine aorta. Cadmium markedly increased the incorporation of [³H] glucosamine into GAGs in both the cell layer and the conditioned medium but decreased [³⁵S] sulfate in the cell layer. This suggested that cadmium induced the GAG synthesis by endothelial cells accompanied by a reduction of the sulfation of cell-associated GAGs. Of the tested heavy metals, the [³⁵S] sulfate incorporation in the cell layer was significantly decreased by lead ; zinc slightly but significantly increased the [³⁵S] sulfate incorporation ; manganese and copper failed to change the [³H] glucosamine and [³⁵S] sulfate incorporation ; and the incorporation of [³H] glucosamine was increased only by cadmium. On the other hand, vascular smooth-muscle cells and fibroblastic Balb/3T3 cells responded to cadmium in a way similar to vascular endothelial cells, while fibroblastic IMR-90 cells, Chang liver cells and epithelial LLC-PK1 cells altered the [³H] glucosamine and [³⁵S] sulfate incorporation after exposure to cadmium in different manners. The alteration of GAGs induced by cadmium may be involved in the pathogenesis of the metal.