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

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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.