[Serum hepatocyte growth factor (HGF) in patients with inflammatory myopathies]

The hepatocyte growth factor (HGF) regulates growth, motility, and morphogenesis of epithelial and endothelial cells. It has been reported that serum level of HGF was elevated in patients with having fulminant hepatitis. In inflammatory myopathies (IM), muscle cells are damaged by the inflammatory process and subsequently regenerated. HGF may be involved in the regeneration process of muscle cells in IM. We examined serum HGF was measured by ELISA from 13 patients with having polymyositis (PM), 18 patients with having dermatomyositis (DM), 3 patients with amyopathic dermatomyositis (ADM) and 14 normal individuals. The muscle of IM patients was examined by immunofluorescence staining using a monoclonal anti-HGF antibody. The serum HGF level was significantly higher in IM patients (0.63 +/- 0.11 (p = 0.028) in PM, 0.58 +/- 0.07 (p = 0.023) in DM) than in normal controls (0.26 +/- 0.01 ng/ml). However, there was no relationship between the serum HGF level and hepatic enzyme level in IM. The levels of serum HGF were significantly higher in active disease (1.05 +/- 0.26 ng/ml) than in inactive disease (0.29 +/- 0.03 ng/ml) (p = 0.044). The serum HGF levels (0.77 +/- 0.12 ng/ ml) were significantly higher in IM patients with pulmonary fibrosis than in those (0.42 +/- 0.04 ng/ml) without pulmonary fibrosis (p = 0.049). There was a positive relationship between serum HGF levels and the presence of opaque fiber and/or regeneration/degeneration fiber in biopsied muscles. HGF was detected in muscles from IM patients by immunofluorescence. Serum HGF levels are elevated in IM and correlated with disease activity and complication of interstitial pneumonia.