Effect of sera from male type I (insulin-dependent) diabetics on human aortic smooth muscle cells in culture

Abstract

Abstract. The effects of sera from male type I (insulin-dependent) diabetics in variable metabolic control were studied on the proliferation and the synthesis of hyaluronic acid, collagen and non-collagenous proteins in cultured human aortic smooth muscle cells (HSMCs). Sera from diabetics in poor metabolic control had a decreased growth-promoting effect on HSMCs as compared with that of sera from non-diabetic healthy male controls. The synthesis of hyaluronic acid in HSMCs was increased in the presence of type I diabetic sera, irrespective of the metabolic control of serum donors. The synthesis of collagen by HSMCs was stimulated only by the diabetic sera which were derived from diabetics in poor metabolic control. The synthesis of non-collagenous proteins in HSMCs was not affected by type I diabetic sera. The stimulatory effect of diabetic sera on hyaluronic acid synthesis by HSMCs correlated inversely with plasma HDL cholesterol of serum donors, whereas the effect of diabetic sera on DNA and collagen syntheses in HSMCs showed an inverse correlation with plasma triglycerides of serum donors. Plasma insulin-like growth factor-I did not correlate with the above functions of HSMCs. Addition of insulin and growth hormone directly into HSMC cultures had no effect on the proliferation or synthesis of connective tissue macromolecules of HSMCs. The results suggest that type I diabetic sera contain factors other than insulin, growth hormone or insulin-like growth factor-I that affect the proliferation and synthesis of hyaluronic acid and collagen of HSMCs in culture. The activity of the factors on cell proliferation and synthesis of collagen is related to some extent to the degree of the metabolic control of the diabetics.