A study on human umbilical cord endothelial cells: Functional modifications induced by plasma from insulin-dependent diabetes mellitus patients

The aim of the present study was to evaluate the action of plasma from insu lin-dependent diabetic (IDDM) pregnant women on nitric oxide synthase (NOS) activity in cultured human umbilical vein endothelial cells (HUVECs). We a lso studied the effect of the plasma on cytosolic calcium and on Na+/K+-ade nosine triphosphatase (ATPase) activity. Dynamic fluorescence studies of me mbrane fluidity were contemporarily performed to detect a direct effect of plasma on the endothelial cell membrane. We observed a significant increase in NOS activity, intracellular calcium, and Na+/K+-ATPase activity in cult ured HUVECs exposed to IDDM plasma. Our dynamic fluorescence study showed a different microenvironmental organization of the cellular membrane after i ncubation with plasma from IDDM pregnant women, with a marked decrease in m icroheterogeneity as evaluated in terms of 1-(4-trimethylaminophenyl)-6-phe nyl-1,3, (TMA-DPH) lifetime distribution width. The present investigation s uggests that plasma from IDDM pregnant women can cause a generalized distur bance in the function of endothelial cells cultured from healthy subjects. Such a modification might play a central role in the pathogenesis of the va scular complications of the disease. Copyright (C) 1999 by W.B. Saunders Co mpany.