Slight activation of nuclear factor kappa-B is associated with increased hepatic stellate cell apoptosis in human schistosomal fibrosis

To investigate the relationship between NF-κB activation and hepatic stellate cell (HSC) apoptosis in hepatosplenic schistosomiasis, hepatic biopsies from patients with Schistosoma mansoni-induced periportal fibrosis, hepatitis C virus-induced cirrhosis, and normal liver were submitted to α-smooth muscle actin (α-SMA) and NF-κB p65 immunohistochemistry, as well as to NF-κB Southwestern histochemistry and TUNEL assay. The numbers of α-SMA-positive cells and NF-κB- and NF-κB p65-positive HSC nuclei were reduced in schistosomal fibrosis relative to liver cirrhosis. In addition, increased HSC NF-κB p65 and TUNEL labeling was observed in schistosomiasis when compared to cirrhosis.These results suggest a possible relationship between the slight activation of the NF-κB complex and the increase of apoptotic HSC number in schistosome-induced fibrosis, taking place to a reduced HSC number in schistosomiasis in relation to liver cirrhosis. Therefore, the NF-κB pathway may constitute an important down-regulatory mechanism in the pathogenesis of human schistosomiasis mansoni, although further studies are needed to refine the understanding of this process.