EXPRESSION OF CYTOSKELETAL PROTEINS AND ATPASE ACTIVITY IN BOVINE FEMORAL-ARTERY AND VEIN INTIMA

Intimal cells play an important role in the biology of the vascular wa ll. Variability in the metabolic activity of intimal smooth muscle cel ls (SMC), as well as the differential expression of cellular cytoskele tal proteins depend on factors such as degree of differentiation, agin g, atherosclerosis, etc. Myosin ATPase activity and cytoskeletal prote ins were studied in the intima of bovine femoral arteries and veins of mature animals. In some arteries the intima was thickened and two dis tinct layers - inner elastic hyperplastic (EHL) and outer, musculo-ela stic (MEL) were observed. ATPase activity was well defined in endothel ial cells (EC) as well as in SMC. However, differential enzymatic expr ession was observed in thickened intimas. SMC in the EHL were ATPase n egative, while in the MEL they were ATPase positive. All EC and SMC in the ''normal'' intimas were vimentin positive, desmin and cytokeratin negative. In vessels with thickened intimas, the EHL showed intensive vimentin positivity; in the MEL desmin immunoreactive SMC were numero us as were as those in the media. Vimentin-positive SMC occupied their innermost part. Differences in the expression of ATPase activity and cytoskeletal proteins is discussed in terms of possible migration of m edial SMC and/or morphological modulation observed in vessels with alt ered vascular walls.