Diabetes, Vol 38, Issue 2 212-218, Copyright © 1989 by American Diabetes Association
Modification of tissue-factor mRNA and protein response to thrombin and interleukin 1 by high glucose in cultured human endothelial cells
D Boeri, FE Almus, M Maiello, E Cagliero, LV Rao and M Lorenzi
Department of Medicine, University of California, San Diego.
Because diabetic vascular disease is accompanied by a state of
hypercoagulability, manifested by increased thrombin activity and foci of
intravascular coagulation, we investigated whether a specific procoagulant
property of the endothelium--production and surface expression of tissue
factor--is modified by elevated glucose concentrations. In unperturbed
human vascular endothelial cells, tissue factor mRNA and expression of the
functional protein were undetectable and were not induced by 10-12 days of
exposure to 30 mM glucose. In thrombin-stimulated cultures, tissue-factor
expression was related inversely to cellular density, with confluent
cultures producing (per 10(5) cells) half the amount of tissue factor
measured in sparse cultures. Cells exposed to high glucose and studied when
cell number and thymidine incorporation were identical to control cells
manifested increased tissue-factor mRNA level and functional protein
production in response to thrombin (P = .002). This effect was not
attributable to hypertonicity and was not observed after short exposure to
high glucose. In contrast, the tissue-factor response to interleukin 1, a
modulator of endothelial function in the context of host defense, was
decreased in cells cultured in high glucose (P = .04). These findings
indicate that exposure to high glucose can alter tissue-factor gene
expression in perturbed vascular endothelium. The reciprocal effects of
high glucose on the tissue-factor response to thrombin and interleukin 1
points to different pathways of tissue-factor stimulation by the two agents
and suggests functional consequences pertinent to the increased thrombin
activity and compromised host-defense mechanisms observed in diabetes.