RESPONSIVENESS TO GROWTH-FACTORS IN AORTIC VASCULAR SMOOTH-MUSCLE CELLS FROM RATS WITH CIRRHOSIS

Hemodynamic changes in cirrhosis may be associated with alterations in aortic vascular smooth muscle cell (AVSMC) function. The present stud y compared the proliferative response to serum and growth factors in c irrhotic and control AVSMC. Serum from cirrhotic rats, cirrhotic ic ce ll lysates, and the conditioned medium of cultured cirrhotic AVSMC ind uced an increase in [H-3]thymidine incorporation in control but not in cirrhotic AVSMC. Platelet-derived growth factor-beta (PDGF-BB) induce d a greater increase in [H-3]thymidine incorporation in cirrhotic than in control cells. [H-3]thymidine incorporation induced by cirrhotic c onditioned medium was blocked by anti-PDGF antibody. Immunoblot studie s showed that the anti-PDGF antibody recognized a 30-kDa protein in th e conditioned medium of cirrhotic AVSMC culture, a protein correspondi ng to PDGF. Binding studies of PDGF-BB indicated a two-fold increase i n receptor density in cirrhotic AVSMC with no alteration in affinity f or PDGF-BB. We conclude that an increased responsiveness of cirrhotic AVSMC to the PDGF could contribute to alterations in AVSMC and muscle eel tone that may play a role in the hemodynamic changes in cirrhosis.