The stabilizing effect of glucocorticoids on human endothelial cells in culture

The effect of hydrocortisone, prednisolone and dexamethasone on the stability and viability of cultured human endothelial cells was studied by measuring the release of 51Cr from pre-labelled cells by cell number calculation and by the Trypan-blue test. All glucocorticoids studied, stabilized endothelial cells as demonstrated by a decreased release of 51Cr. The maximal stabilizing effect of the steroids appeared to be equal, although the maximal effect of dexamethasone was seen at a lower concentration than that of prednisolone and hydrocortisone. However, at the very high concentration of 10(-4) mol/l, dexamethasone induced an increase in the release of 51Cr suggesting a toxic effect. The viability of cells was not affected by the steroids. The stabilizing effect of glucocorticoids at optimal concentrations in vitro may indicate strengthening of endothelial integrity by the steroids in vivo. This may explain their beneficial effect in the treatment of certain vascular disorders, e.g. thrombocytopenia.