GAP JUNCTIONAL COMMUNICATION IN PRIMARY CULTURE OF CELLS DERIVED FROMHUMAN AORTIC INTIMA

Intercellular communication via gap junctions plays an important role in the regulation and homeostasis. The presence of gap junctions and t he efficiency of their function directly correlates with the degree of cell differentiation in a tissue, In the present study, gap junctiona l communication has been investigated in a primary culture of highly d ifferentiated mesenchymal cells (subendothelial smooth muscle cells is olated from grossly normal and atherosclerotic areas of human aorta) a nd in poorly differentiated cells of mesenchymal origin (adult human s kin fibroblasts as well as skin fibroblasts and aortic smooth muscle c ells, derived from human fetus), The fluorescent dye transfer techniqu e was used in this study, In cell cultures isolated from grossly norma l and atherosclerotic aorta, the number of cells coupled via gap junct ions increased with cell density and reached a plateau at a cell densi ty of 50 to 70 cells/mm(2). In cultures of normal aortic cells the num ber of coupled cells was 23.0+/-4.1 per injected cell and was signific antly higher than in cultures of atherosclerotic cells (16.4+/-2.1, p< 0.05). Gap junctional communication between cells loaded with lipid in clusions was 2.4-fold lower than between cells free of excess intracel lular lipids. In cultures of human skin fibroblasts the rate of interc ellular communication was lower than in cultures of normal aortic cell s and was comparable to that in cultures of atherosclerotic cells. The re was practically no cell-to-cell communication in cultures of fetal cells. It is hypothesized that the reduced gap junctional communicatio n in atherosclerotic human aorta is associated with the alterations in the degree of smooth muscle cell differentiation and impairs the func tion of the intima in atherosclerosis.