Evidence for erythrocyte-microvesiculation in vivo.

During physiologic aging, erythrocytes (RBC) mainly loose membrane as shown by biochemical investigations. The most likely reason for a such loss would be the pinch off of RBC-microvesicles. The detection of RBC-microvesicles generated in vivo is rendered more difficult because of the relatively small amount of vesiculation processes under physiologic conditions accompanied by the fast phagocytosis of RBC-microvesicles in the reticulo-histiocytic system. The latter has been shown after the intravenous injection of heat-induced RBC-microvesicles. Investigations of spleens resulted in the case of PHZ-treatment, up till now in a clear demonstration of RBC-microvesicles. The result of microvesiculation in the PHZ-model led to the conclusion, that also rigid, naturally aged RBC could pinch off microvesicles in physiologic narrows of the blood flow like in the spleen.