Alterations in cell number and cell morphology in copper deficient endothelial cells

In post‐implantation embryo culture, copper (Cu) deficiency impairs yolk sac vessel development. We used human umbilical vein endothelial cells (HUVEC) to test the hypothesis that the yolk sac vessel anomalies observed in Cu deficiency result from abnormal EC morphology and motility. HUVEC were cultured in low serum (2%) medium for 72 h in chamber slides. The addition of the Cu chelator triethylenepentamine (TEPA) to the culture media resulted in a dose‐dependent decrease in cell number. The addition of 50 uM Cu prevented the reduction in cell viability observed in 10 uM TEPA but not in 50 uM TEPA treated cells. To test the effects of Cu on EC cytoskeleton, HUVEC were grown for 72 h in culture media containing 10 or 50 uM TEPA, with and without 50 uM Cu and processed for fluorescence microscopy. In control medium, actin was organized into stress fibers; tubulin filaments extended from the perinuclear organizing center to the periphery. HUVEC grown in medium containing 10 uM TEPA showed marked reductions in actin filaments; the cells appeared round and hollow. Tubulin extensions were reduced in the Cu deficient cells. These effects we exacerbated at 50 uM TEPA. The addition of 50 uM Cu to 10 uM TEPA treated cells restored the expression patterns of actin and tubulin similar to control; but not at 50 uM TEPA. These data suggest that Cu deficiency disturbs the organization of the cytoskeleton. We are investigating the functional implications of this pattern of expression in endothelial cells. (Supported by AHA 0465074Y).