EXPRESSION OF PLATELET-DERIVED GROWTH-FACTOR AND ITS RECEPTOR IN LIVERS OF PATIENTS WITH CHRONIC LIVER-DISEASE

To find if platelet-derived growth factor contributes to liver fibrosi s in chronic liver disease, we studied the expression of the B-chain o f this cytokine and its beta-receptor in livers of patients with chron ic hepatitis or cirrhosis. Seventeen patients were included in this st udy. Five specimens of liver tissue obtained during autopsy from subje cts without liver disease were used as controls, The location of the p eptides was identified by an immunohistochemical technique with monocl onal antibodies. Expression of mRNA for the B-chain was assessed by in situ hybridization. Cells stained for the B-chain and expressing its mRNA were identified as macrophages. In control tissues, only a few ce lls were stained. In the patients' specimens, most stained cells were in portal areas and their number increased with histologic liver damag e. In intralobular areas, the stained cells were seen in regions of fo cal necrosis. Portal mesenchymal and perisinusoidal cells expressed Pr eceptor. These cells were dense in periportal areas, where many myofib roblast-like cells were seen. These findings suggest that the B-chain of platelet-derived growth factor is released mainly by macrophages in volved in inflammatory reactions. This cytokine probably acts on myofi broblast-like mesenchymal cells, and may be implicated in liver fibros is in chronic liver disease.