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Evidence for erythrocyte-microvesiculation in vivo
Abstract:
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.
Insights
Physiologic aging causes red blood cells (RBCs) to lose membrane, likely through microvesicle shedding. This study demonstrates that aged RBCs can release microvesicles in narrow blood flow, such as the spleen.
Area of Science:
- Hematology
- Cell Biology
- Physiology
Background:
- Erythrocytes (RBCs) lose membrane during aging.
- Microvesicle shedding is a proposed mechanism for membrane loss.
- In vivo detection of RBC microvesicles is challenging due to low levels and rapid clearance.
Purpose of the Study:
- To investigate the shedding of microvesicles from aged red blood cells.
- To explore the role of microvesiculation in RBC aging.
- To provide evidence for in vivo microvesicle formation from aged RBCs.
Main Methods:
- Biochemical investigations of aged erythrocytes.
- Analysis of spleen tissues following phenylhydrazine (PHZ) treatment.
- Intravenous injection of heat-induced RBC microvesicles to study clearance.
Main Results:
- Biochemical data support membrane loss in aging RBCs.
- PHZ-induced treatment clearly demonstrated RBC microvesicles in spleen.
- RBC microvesicles injected intravenously were rapidly cleared by the reticulo-histiocytic system.
Conclusions:
- Aged, rigid RBCs can shed microvesicles.
- Microvesiculation likely occurs in narrow blood flow areas like the spleen.
- This process contributes to membrane loss during physiologic RBC aging.