Myofibroblast-Like Cells Produce mRNA for Type I and III Procollagens in Chronic Active Hepatitis

Abstract

In chronic active hepatitis the rate of collagen biosynthesis is largely determined by intracellular mRNA concentrations. To localize procollagen mRNA-producing cells, we investigated biopsy specimens from five patients with hepatitis B surface antigen-positive chronic active hepatitis and five patients without liver disease by in situ hybridization. We used type I and III procollagen cDNAs for transcription to (³⁵S)-labeled probes. Parallel sections were stained with anti-actin monoclonal antibodies. Our results show that cells in which collagen synthesis is ostensibly enhanced can be localized by in situ hybridization of procollagen mRNAs. These cells were also anti-actin-positive in parallel sections and were localized in areas of inflammatory cell infiltration and necrosis. We conclude that myofibroblast-like cells may express procollagen mRNAs in chronic active hepatitis. Moreover, in situ hybridization may be a valuable diagnostic tool for providing additional morphologic information on the degree of fibrogenesis activity.

Key Words:

• Anti-actin
• chronic active hepatitis
• collagen synthesis
• in situ hybridization
• ITO-cells
• liver fibrosis
• myofibroblast-like cells
• procollagen type I and type III
• procollagen III peptide