Role of staphylococcus aureus hemolytic toxin-alpha in pathogenesis of infectious endocarditis: studies in vitro

AIM: To study effects of alpha-toxin (AT) Staphylococcus aureus on human platelets and endothelial cells. MATERIALS AND METHODS: Concentrations of intracellular calcium in human platelets and endothelial cells were estimated by fluorescence, phosphoinositide metabolism in the endothelial cells was studied using 3H-myoinositole. RESULTS: AT induced a dose-dependent increase of intracellular calcium in blood and vascular cells, stimulates dose-dependent formation of inositol phosphates in endothelial cells. CONCLUSION: AT action on the platelets and endothelial cells results in a significant receptor-independent rise in concentration of intracellular calcium, activation of phosphoinositide metabolism, death of cells. These data support the hypothesis that the platelet and endothelial cell damage is mostly due to the passive Ca2+ influxvia pores formed by AT in cellular membrane.