In Vivo Shear Stress Determines Circulating Levels of Endothelial Microparticles in End-Stage Renal Disease

Abstract

Shear stress is a major determinant of endothelial apoptosis, but its role in the in vivo release of shed membrane microparticles by endothelial cells remains unknown. Thus, we sought to evaluate the possible relationship between circulating endothelial microparticle levels and laminar shear stress in end-stage renal disease patients with high cardiovascular risk, whose levels of endothelial microparticles are elevated. In 34 hemodialyzed patients, we analyzed the relationships between brachial artery and aortic shear stress and circulating microparticles levels. Only endothelial microparticles were inversely correlated with laminar shear stress values (P<0.0001) or its components shear rate and whole blood viscosity, independent of age or arterial blood pressure. Changes in hematocrit resulting from hemodialysis-induced hemoconcentration or erythropoietin anemia improvement induced a significant increase in whole blood viscosity and shear stress and were associated with a significant decrease in endothel...