Myofibroblasts in schistosomal portal fibrosis of man

Myofibroblasts, cells with intermediate features between smooth muscle cell s and fibroblasts, have been described as an important cellular component o f schistosomal portal fibrosis. The origin, distribution and fate of myofib roblasts were investigated by means of light, fluorescent immunoenzymatic a nd ultrastructural techniques in wedge liver biopsies from 68 patients with the hepatosplenic form of schistosomiasis. Results demonstrated that the p resence of myofibroblasts varied considerably from case to case and was alw ays related to smooth muscle cell dispersion, which occurred around medium- sized damaged portal vein branches. By sequential observation of several ca ses, it was evident that myofibroblasts derived by differentiation of vascu lar smooth muscle and gradually tended to disappear some of them further di fferentiating into fibroblasts. Thus, in schistosomal pipestem fibrosis myo fibroblasts appear as transient cells, focally accumulated around damaged p ortal vein branches, and do not seem to have by themselves any important pa rticipation in the pathogenesis of hepatosplenic schistosomiasis.