HUMAN ENDOTHELIAL-CELLS ARE DEFECTIVE IN DIABETIC VASCULAR-DISEASE

Diabetic vascular disease is characterized pathologically by endotheli al cell (EC) hyperplasia and basement membrane (BM) thickening. One ke y question regarding the pathogenesis of diabetic vascular disease is whether the EC or BM or both are primarily defective and responsible f or these pathological changes. Previous studies, which took the approa ch of creating artificial diabetic conditions, have been inconclusive; It is known, however, that the extracellular matrix may be altered by glycosylation as a result of hyperglycemia, thereby altering EC funct ion. To begin to address this question and more closely mimic the situ ation in vivo, we characterized human diabetic EC harvested from insul in-dependent diabetic mothers (IDDM) at the cellular and molecular lev els. Human EC were isolated from both normal and IDDM umbilical cords and cellular functions evaluated using standard assays of attachment ( % attached cells), proliferation (cpm/cell), resistance to detachment under shear stress (number of cells remaining attached), and glucose u ptake (cpm/2 X 10(4) cells). Gene expression of major BM components (c ollagen type IV, laminin beta 1, and laminin beta 2) was quantified by Northern analysis. Diabetic EC demonstrated increased proliferation ( two- to eightfold compared td normals), were 20-40% less resistant to shear stress and took up glucose 10-15% more slowly than normal EC. Fu rthermore, Northern analysis showed that the expression of major BM co mponents was increased by an average of 10-18% in diabetic cells compa red to normal cells. These results were consistent with in vivo observ ations and previously published data. The preservation of diabetic cha racteristics by diabetic EC in the absence of diabetic or glycosylated BM suggests that EC may be the site of an additional primary defect i n DM that may contribute to the development of vascular diseases. (C) 1994 Academic Press, Inc.