Shear-stress effect on mitochondrial membrane potential and albumin uptakein cultured endothelial cells

Endothelial cells (ECs) that line the inner surface of blood vessels are co ntinuously exposed to shear stress induced by blood flow in vivo and shear stress affects ATP-dependent macromolecular transport in ECs. However, the relationship between the ATP production and shear stress is still unclear. We, therefore, evaluated mitochondrial ATP synthesis activity in cultured e ndothelial cells exposed to shear stress, using a confocal laser scanning m icroscope (CLSM) and a mitochondrial membrane potential probe (5,5',6,6'-te trachloro-1,1',3,3'-tetraethyl-benzimidazolycarbocyanine iodide, JC-l). Low shear stress (10 dyn/cm(2)) increased mitochondrial membrane potential by 30%. On the contrary, high shear stress (60 dyn/cm(2)) decreased it by 20%. This observation was consistent with the ATP-dependent albumin uptake into endothelial cells. Our results indicate that ATP synthetic activity is rel ated to the albumin uptake into endothelial cells. (C) 2000 Academic Press.