Hepatitis: Jeong WI

Gao B, Radaeva S, Jeong WI. · Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Room 2S-33, Bethesda, MD 20892-8115, USA. · Expert Rev Gastroenterol Hepatol. · Pubmed #19072444 No free full text.

Abstract: Liver lymphocytes are enriched in natural killer (NK) cells, which are involved in innate immune defenses against viral infection and tumor transformation in the liver. Recent evidence indicates that NK cell activation by IFN-alpha, IFN-gamma or dsRNA attenuates liver fibrosis through the direct killing of activated hepatic stellate cells (HSCs). Interestingly, NK cells do not kill quiescent or fully activated HSCs, but only early-activated HSCs, as only these cells express elevated levels of the NK cell-activating ligand retinoic acid-induced early transcript (RAE)-1 and TNF-related apoptosis-inducing ligand receptors, in addition to downregulated levels of the NK-cell inhibitory ligand, MHC-I. Inhibition of liver fibrosis by NK cells can also be achieved through production of IFN-gamma, which induces HSC cell cycle arrest and apoptosis in a STAT1-dependent manner. Clinically, it has also been observed that NK cell activity is negatively correlated with liver fibrosis in patients with chronic hepatitis C infection. Therefore, since NK cells inhibit liver fibrosis, stimulating NK activity could potentially be a novel strategy to treat liver fibrosis. Clinical studies will be required to confirm whether stimulating NK cell activity is effective and safe in treating human liver fibrosis.

Park O, Jeong WI, Wang L, Wang H, Lian ZX, Gershwin ME, Gao B. · Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA. · Hepatology. · Pubmed #19205035 No free full text.

Abstract: Liver fibrosis is a common scarring response to all forms of chronic liver injury and is always associated with inflammation that contributes to fibrogenesis. Although a variety of cell populations infiltrate the liver during inflammation, it is generically clear that CD8 T lymphocytes promote while natural killer (NK) cells inhibit liver fibrosis. However, the role of invariant natural killer T (iNKT) cells, which are abundant in the liver, in hepatic fibrogenesis, remains obscure. Here we show that iNKT-deficient mice are more susceptible to carbon tetrachloride (CCl(4))-induced acute liver injury and inflammation. The protective effect of naturally activated iNKT in this model is likely mediated via suppression of the proinflammatory effect of activated hepatic stellate cells. Interestingly, strong activation of iNKT through injection of iNKT activator alpha-galactosylceramide (alpha-GalCer) accelerates CCl(4)-induced acute liver injury and fibrosis. In contrast, chronic CCl(4) administration induces a similar degree of liver injury in iNKT-deficient and wild-type mice, and only a slightly higher grade of liver fibrosis in iNKT-deficient mice than wild-type mice 2 weeks but not 4 weeks after CCl(4) injection, although iNKT cells are able to kill activated stellate cells. An insignificant role of iNKT in chronic liver injury and fibrosis may be attributable to hepatic iNKT cell depletion. Finally, chronic alpha-GalCer treatment had little effect on liver injury and fibrosis, which is attributable to iNKT tolerance after alpha-GalCer injection. Conclusion: Natural activation of hepatic iNKT cells inhibits, whereas strong activation of iNKT cells by alpha-GalCer accelerates CCl(4)-induced acute liver injury, inflammation, and fibrosis. During chronic liver injury, hepatic iNKT cells are depleted and play a role in inhibiting liver fibrosis in the early stage but not the late stage of fibrosis.

Jeong WI, Park O, Gao B. · Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA. · Gastroenterology. · Pubmed #18166357 No free full text.

Abstract: BACKGROUND & AIMS: Chronic alcohol drinking accelerates liver fibrosis in patients with viral hepatitis that cannot be fully explained by ethanol-enhanced liver damage. Here, we identified a novel mechanism by which alcohol accelerates liver fibrosis: inhibition of the antifibrotic effects of natural killer (NK) cells and interferon-gamma (IFN-gamma). METHODS: Alcohol administration was achieved by feeding mice with a liquid diet containing 5% ethanol for 8 weeks. Liver fibrosis was induced by administration of carbon tetrachloride (CCl(4)) for 2 weeks. Hepatic stellate cells (HSCs) were also isolated and cultured for in vitro studies. RESULTS: CCl(4) treatment induced greater fibrosis and less apoptosis of HSCs in ethanol-fed mice compared with pair-fed mice. Polyinosinic-polycytidylic acid (Poly I:C) or IFN-gamma treatment inhibited liver fibrosis in pair-fed but not in ethanol-fed mice. Poly I:C activation of NK cell cytotoxicity against HSCs was attenuated in ethanol-fed mice compared with pair-fed mice, which was due to reduced natural killer group 2 member D (NKG2D), tumor necrosis factor-related apoptosis-inducing ligand, and IFN-gamma expression on NK cells from ethanol-fed mice. In vitro, HSCs from ethanol-fed mice were resistant to IFN-gamma-induced cell cycle arrest and apoptosis compared with pair-fed mice. Such resistance was due to diminished IFN-gamma activation of signal transducer and activator of transcription 1 (STAT1) in HSCs from ethanol-fed mice caused by the induction of suppressors of cytokine signaling proteins and the production of oxidative stress. Finally, HSCs from ethanol-fed mice were resistant to NK cell killing, which can be reversed by transforming growth factor-beta1 (TGF-beta1) neutralizing antibody. CONCLUSIONS: Chronic ethanol consumption attenuates the antifibrotic effects of NK/IFN-gamma/STAT1 in the liver, representing new and different therapeutic targets with which to treat alcoholic liver fibrosis.

Lee CW, Jeong WI, Noh DH, Jeong DH, DO SH, Kim YK, Kwon OD, Kim TH, Jeong KS. · Department of Veterinary Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea. · J Vet Med Sci. · Pubmed #15876791 links to  free full text

Abstract: Among many detrimental injuries, alcohol is implicated in hepatitis, fatty liver, hepatic fibrosis, and cirrhosis. The purpose of this study was to evaluate the protective effect of bio-active ceramic water on alcohol-induced hepatic injury in pigs. Twelve male Landrace pigs were divided into 3 groups. Groups 1, 2, and 3 were fed with bio-active ceramic water + normal liquid diet, bio-active ceramic water + liquid diet containing 15% ethanol, and tap water + liquid diet containing 15% ethanol for 12 weeks, respectively. For serological, histopathological, and immunohistochemical analysis, all pigs were sacrificed at week 12. In group 3, serum ALT and AST levels increased, and mild fatty change and moderate necrosis were detected in the liver. Collagen fibers, myofibroblasts, and CYP2E1 were also increased or activated in group 3. In group 2, there were mild hepatic injuries compared to group 3. However, injuries and activations were not observed in the liver in group 1. We suggest that the bio-active ceramic water used in the present study had protective capability against ethanol-induced hepatic injury and that having no toxic effect on the pig liver. The bio-active ceramic water might be useful as a therapeutic drinking water in patients suffering from alcoholic liver diseases.

Jeong DH, Lee GP, Jeong WI, Do SH, Yang HJ, Yuan DW, Park HY, Kim KJ, Jeong KS. · College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Republic of Korea. · World J Gastroenterol. · Pubmed #15754394 links to  free full text

Abstract: AIM: Silymarin is a potent antioxidant, antiinflammatory and anti-fibrogenic agent in the liver, which is mediated by alteration of hepatic Kupffer cell function, lipid peroxidation, and collagen production. Especially, in hepatic fibrogenesis, mast cells are expressed in chronic inflammatory conditions, and promote fibroblast growth and stimulate production of the extracellular matrix by hepatic stellate cells. METHODS: We examined the inhibitory mechanism of silymarin on CCl(4)-induced hepatic cirrhosis in rats. At 4, 8, and 12 wk, liver tissues were examined histopathologically for fibrotic changes produced by silymarin treatment. RESULTS: In the silymarin with CCl(4)-treated group, increase of hepatic stellate cells and TGF-beta1 production were lower than in the CCl(4)-treated group at early stages. Additionally, at the late fibrogenic stage, expressions of TGF-beta1 were weaker and especially not expressed in hepatocytes located in peripheral areas. Moreover, the number of mast cell in portal areas gradually increased and was dependent on the fibrogenic stage, but those of CCl(1)+silymarin-treated group decreased significantly. CONCLUSION: Anti-fibrotic and antiinflammatory effects of silymarin were associated with activation of hepatic stellate cells through the expression of TGF-beta1 and stabilization of mast cells. These results suggest that silymarin prevent hepatic fibrosis through suppression of inflammation and hypoxia in the hepatic fibrogenesis.

Jeong DH, Jeong WI, Chung JY, An MY, Jung CY, Lee GJ, Kang JS, Kang BC, Jee YH, Williams BH, Kwon YO, Jeong KS. · College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Korea. · J Vet Sci. · Pubmed #14610377 links to  free full text

Abstract: Histologic and clinicopathologic findings of a woodchuck (Marmota monax) vertically infected with woodchuck hepatitis virus (WHV) are presented. The liver exhibits marked cirrhotic changes, which is characteristic of the pre-transformation phase of WHV. At necropsy, the woodchuck exhibited ascites and the liver had a grossly nodular appearance. Microscopically, focal hepatocyte necrosis and inflammatory cells were observed in midzonal and periportal areas in the liver. In Macchiavellos stained sections, cytoplasmic inclusion bodies appeared reddish granular materials. We believe that this may represent a new suitable and cost-effective cirrhotic model for the disease processes associated with hepadnaviruses in a number of other species, most notably Hepatitis B virus infection in man.