ABNORMAL DEPOSITION OF EXTRACELLULAR-MATRIX PROTEINS BY CULTURED SMOOTH-MUSCLE CELLS FROM HUMAN VARICOSE-VEINS

The aim of the present study was to verify whether the modifications o f the extracellular matrix, described in varicose veins, are also pres ent in cultures of smooth muscle cells from human varicose veins. The accumulation of collagen type III and fibronectin was determined by im munofluorescence in cultures of smooth muscle cells at passage 2-3 dur ing the proliferation phase. After 5 days of culture, the immunostaini ng of both collagen type III and fibronectin was weaker in cells from varicose than in those of control veins while the expression of collag en type III and fibronectin messenger ribonucleic acids was not signif icantly different. Collagen type I and III synthesis were quantified b y tritiated proline incorporation in control and varicose cell layers at postconfluence. Collagen type I deposition was similar in both type s of cell layers while collagen type III was decreased in cell layers from varicose veins. Matrix metalloproteinases (MMPs) and their inhibi tors (TIMPs) were also quantified by enzyme immunoassays in supernatan ts from smooth muscle cell cultures at postconfluence. No significant difference was observed in the synthesis of any of the MMPs (-1, -2 an d -9) or their inhibitors (-1 and -2) tested. These data illustrate th at smooth muscle cells cultured from varicose veins deposit less colla gen type III and fibronectin than control cells despite comparable lev els of mRNAs for these proteins suggesting dysregulation of posttransl ational steps in the synthesis of both proteins by smooth muscle cells from varicose veins.