Purification and Characterization of Hepatocyte Regeneration Stimulatory Factor from Shark Liver

Aim To purify hepatocyte regeneration stimulatory factor from shark liver and research its molecular feature and activity. Methods and Results Hepatocyte regeneration stimulatory factor (sHRSF) was isolated from healthy shark livers and separated by homogenization, freezing melting, heat treating, centrifugation, and ultrafiltration. HRSF activity was found mainly in the subfraction of molecular weight less than 30 000 daltons. This crude ultrafiltrate was further purified successively by DEAE Sepharose fast flow chromatography, FPLC Resource 30Q, Resource Q and Mono Q chromatography. A single band was displayed on sodium dodecyl sulfate polyacrylamide gel electrophoresis, which corresponds to molecular weight of 14 600 daltons. The characteristic absorption was obtained at the wavelength 276 nm. The isoelectric point was about 5 1. It contained 18 amino acids and the 15 N terminal amino acid residues were LVGPIGAVGPAGKDG. It had a significant activity in stimulating liver to regenerate. Conclusion We obtained an unknown new active protein, that is hepatocyte regeneration stimulatory factor from shark liver (sHRSF).

Increased hepatic expression of insulin-like growth factor-Ⅰreceptor in chronic hepatitis C

AIM： Although increased insulin-like growth factor-I receptor （IGF-IR） gene expression has been reported in hepatocellular carcinoma, studies assessing IGF-IR in chronic hepatitis C （CHC） and cirrhosis are scarce. We therefore aimed to evaluate IGF-IR and IGF-I rnRNA expression in liver from patient with CHC. METHODS： IGF-IR and IGF-I rnRNA content were determined by semi-quantitative RT-PCR and IGF-IR protein expression was determined by immunohistochemistry in hepatic tissue obtained from patients with CHC before （34 patients） and after （10 patients） therapy with interferon-α and ribavirin. RESULTS： An increase of IGF-IR rnRNA content was observed in hepatic tissue obtained from all CHC patients as well as from 6 cadaveric liver donors following orthopic transplantation （an attempt to evaluate normal livers） in comparison to normal liver, while no relevant modifications were detected in IGF-I mRNA content. The irnrnunohistochemical results showed that the raise in IGF-IR rnRNA content was related both to ductular reaction and to increased IGF-IR expression in hepatocytes. A decrease in IGF-IR rnRNA content was observed in patients who achieved sustained virological response after therapy, suggesting an improvement in hepatic damage. CONCLUSION： The up-regulation of IGF-IR expression in hepatocytes of patients with CHC could constitute an attempt to stimulate hepatocyte regeneration. Considering that liver is the organ with the highest levels of IGF-I, our finding of increased IGF-IR expression after both acute and chronic hepatic damage highlights the need for additional studies to elucidate the role of IGF-I in liver regeneration.

Ductular proliferation in liver tissues with severe chronic hepatitis B: An immunohistochemical study

AIM： To clarify the pathogenesis of ductular proliferation and its possible association with oval cell activation and hepatocyte regeneration. METHODS： Immunohistochemical staining and image analysis of the ductular structures in the liver tissues from 11 patients with severe chronic hepatitis B and 2 healthy individuals were performed. The liver specimens were sectioned serially, and then cytokeratin 8 （CK8）, CK19, OV6, proliferating cell nuclear antigens （PCNA）, glutathione-S-transferase （GST）, α-fetal protein （AFP） and albumin were stained immunohistochemically. RESULTS： Typical and atypical types of ductular proliferation were observed in the portal tracts of the liver tissues in all 11 patients. The proliferating ductular cells were positive for CKS, CK19, OV6 and PCNA staining. Some atypical ductular cells displayed the morphological and immunohistochemical characteristics of hepatic oval cells. Some small hepatocyte-like cells were between hepatic oval cells and mature hepatocytes morphometrically and immunohistochemically. CONCLUSION： The proliferating ductules in the liver of patients with severe chronic liver disease may have different origins. Some atypical ductular cells are actually activated hepatic oval cells. Atypical ductular proliferation is related to hepatocyte regeneration and small hepatocyte-like cells may be intermediate transient cells between hepatic oval cells and mature hepatocytes.

Molecular pathogenesis of acetaminophen-induced liver injury and its treatment options

Acetaminophen,also known as N-acetyl-p-aminophenol(APAP),is commonly used as an antipyretic and analgesic agent.APAP overdose can induce hepatic toxicity,known as acetaminophen-induced liver injury(AILI).However,therapeutic doses of APAP can also induce AILI in patients with excessive alcohol intake or who are fasting.Hence,there is a need to understand the potential pathological mechanisms underlying AILI.In this review,we summarize three main mechanisms involved in the pathogenesis of AILI:hepatocyte necrosis,sterile inflammation,and hepatocyte regeneration.The relevant factors are elucidated and discussed.For instance,N-acetyl-p-benzoquinone imine(NAPQI)protein adducts trigger mitochondrial oxidative/nitrosative stress during hepatocyte necrosis,danger-associated molecular patterns(DAMPs)are released to elicit sterile inflammation,and certain growth factors contribute to liver regeneration.Finally,we describe the current potential treatment options for AILI patients and promising novel strategies available to researchers and pharmacists.This review provides a clearer understanding of AILI-related mechanisms to guide drug screening and selection for the clinical treatment of AILI patients in the future.