Individual, culture-specific alterations in the human endothelial glutathione system: relationships to oxidant toxicity

In this communication we report on the effects of serial passage of human umbilical vein endothelial cells on the levels of GSH and activities of selenium-dependent GSH peroxidase (SeGSHpx) and GSSG reductase (GSSGred) in confluent monolayers of human umbilical vein endothelial cells derived from 4 individual donors. The mean levels of GSH in confluent monolayers of individual human umbilical vein endothelial cells batches fell from an average of 35 nmol/mg protein to 16 nmol/mg protein from primary culture to the third passage, with little interindividual variation noted. Simultaneously, the mean activities of SeGSHpx and GSSGred remained unaltered during serial culture, again with little interindividual variation noted. However, serial passage of the cells from different individuals did not affect the sensitivity of the cells to sublethal injury induced by H2O2 (10 or 100 microM), as judged by the stimulated release of (3H)-deoxyglucose. When these GSH-dependent parameters were assayed during the coarse of the growth of an individual passage of cells, GSH levels declined following trypsinisation, but the activities of SeGSHpx and GSSGred remained essentially unaltered, when the data were standardised to cell number. On the other hand, standardisation of these data to cell protein revealed decreases in all three parameters following trypsinisation, indicating the introduction of artefacts into the data and the unsuitability of this standardisation procedure. For the first four hours following plating, all of the GSH-dependent parameters remained essentially unaltered, but began increasing thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)