Background:
@EN Thickening of basement membrane is a characteristic change in chronic diabetic complications. Hyperinsulinemia and elevated insulin-like growth factor-(IGF-1) might be associated with acceleration of atherosclerosis and the devleopment of
microvascular complications. We have now determined that insulin and IGF-1 enhanced the expression of basement membrane components such as collagen and fibronectin in endothelial cells and fibroblasts.
@ES Methods :
@EN Dose-responsive effect of insulin (1~1,000ng.ml) and IGF-1 (1~500 ng/ml) on collagen, fibronectin, and DNA synthesis by cultures of bovine capillarly endothelial cells, bovine arterial endothelial cells, and human skin fibroblasts wre
studied.
The
measurement of collagen and noncollagen protein synthesis in these cells were accomplished by labeling with [3H] proline and counting radioactivity in collagenase-sensitive and insensitive protein fractions. Fibronectin synthesis was measured by
ELISA.
DNA synthesis was analyzed by [3H] thymidine incorporation into the cells.
@ES Results :
@EN In bovine capillary endothelial cells, insulin and IGF-1 increased collagen and noncollagen protein (NCP) production, the latter was more prominent than the former, Insulin and IGF-1 also stimulated the production of collagen and NCP by
bovine
arterial endothelial cells but in a lesser extent as compared to the bovine capillary endothelial cells. Insulin and IGF-1 significantly increased DNA synthesis by bovine capillary endothelial cells but not by bovine arterial endothelial cells.
In
human skin fibroblasts, insulin and IGF-1 stimulated collagen, NCP, and DNA synthesis in a greater extent as compared to the bovine capillary endothelial cells.
@ES Conclusions:
@EN Hyperinsulinemia in diabetes might have direct effects on bovine capillary endothelial cells rather than bovine arterial endothelial cells.
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