CORRELATION OF ENDOTHELIAL VIMENTIN CONTENT WITH HEMODYNAMIC PARAMETERS

In mammalian species, vimentin is the sole intermediate filament prote in of endothelial cells lining the chambers of the heart and the inner surface of large blood vessels. Obvious quantitative differences in t he vimentin-like immunoreactivity of endothelial cells observed in dif ferent vascular segments led us to undertake a systematic survey on th e endothelial content of vimentin throughout the heart chambers, the v ena cave, the pulmonary trunk, and the aorta of the pig. Immunostainin g and immunoblotting showed that vimentin in endothelial cells of card iovascular segments exposed to high shear stress and blood pressure (p ulmonary trunk, aorta, left ventricle) is approximately 2- to -3-fold higher than in endothelial cells exposed to lower levels of hemodynami c stress (vena cava, left and right atria, right ventricle). Throughou t the aorta, an approximately 1.5-fold increase in the vimentin conten ts was observed in a proximal to distal direction. The total endotheli al amount of vimentin was determined to be 1.2% (inferior vena cava) a nd 2-3.5% (aorta) of total cellular protein. These data support the no tion that the endothelial vimentin cytoskeleton can adapt to different hemodynamic loads, indicating that vimentin might help endothelial ce lls to withstand the mechanical forces exerted by blood flow and blood pressure.