Elevated serum uric acid level was a notable adverse event during combination therapy with sofosbuvir and ribavirin.

AIM: Combination therapy with sofosbuvir and ribavirin (SOF/RBV) has been recently available for chronic hepatitis C patients with genotype 2 (CHG2) in Japan. The domestic phase III clinical trial showed a high antiviral effect with a relatively safe adverse event (AE) profile. Our aim was to report an important AE detected during treatment. METHODS: A prospective multi-institutional study of 12-week combination therapy with SOF/RBV for CHG2 was carried out to evaluate efficacy and safety. RESULTS: The eligible subjects included 142 patients. Out of 50 assessable patients, 16% of the patients were diagnosed with hyperuricemia. The proportions of subjects with grade 1, grade 3, and grade 4 hyperuricemia were 12, 2, and 2%, respectively. Serum uric acid (UA) levels at week 1 of the therapy (W1) were numerically the highest during therapy in patients with hyperuricemia, and the ratio of W1/baseline serum UA levels was significantly higher than that of post-treatment week 4 or 8/baseline serum UA levels in assessable patients. Serum UA levels at W1 were significantly correlated with body mass index. The difference between serum UA levels at W1 and baseline serum UA levels was significantly correlated with the difference between serum creatinine levels at W1 and baseline serum creatinine levels. CONCLUSIONS: Elevated serum UA level was a notable AE associated with SOF/RBV therapy for CHG2. However, because of the small number of subjects, the exact frequency of AEs should be re-evaluated with larger cohorts. We need to remember that elevated serum UA level might develop during the therapy, especially at W1.

Spontaneous remission of hepatitis B virus reactivation during direct-acting antiviral agent-based therapy for chronic hepatitis C.

The administration of direct-acting antiviral agents (DAAs) to treat hepatitis C virus (HCV) infection has been reported to cause hepatitis B virus (HBV) reactivation. However, the actual conditions of HBV reactivation and the ideal timing of medical intervention have not been fully evaluated. We report the cases of two female patients dually infected with HBV and HCV. Both patients were inactive HBV carriers. Although the serum HCV RNA levels promptly decreased after the initiation of DAA-based therapy, the serum HBV DNA levels gradually increased during DAA-based therapy, with the peak serum HBV DNA levels observed at 16 weeks after the initiation of DAA-based therapy in both cases. Subsequently, we checked the serum HBV DNA levels closely every week several times. Fortunately, the serum HBV DNA levels gradually decreased without medical intervention. Neither case developed an alanine aminotransferase flare-up. The HCV genotypes were 2a and 1b, and the DAA-based therapies of Cases 1 and 2 were 12 weeks of sofosbuvir/ribavirin and ombitasvir/paritaprevir/ritonavir, respectively. The significance of our case reports is the demonstration of the existence of spontaneous remission of HBV reactivation that developed during DAA-based therapy, the avoidance of intervention of nucleot(s)ide analogs by frequent monitoring of serum HBV DNA levels, and development of HBV reactivation regardless of the viral genotype or class of DAA. In conclusion, the close monitoring of serum HBV DNA levels during and after DAA-based therapy is essential and medical intervention for HBV reactivation should be carefully considered on an individual basis.

Clinical and virological features of acute hepatitis E in Gunma prefecture, Japan between 2004 and 2015.

AIM: To evaluate the clinical and virological features of acute hepatitis E (AH-E) in Gunma prefecture and focus on the hepatitis E virus (HEV) infection in immunocompromised patients. METHODS: A total of 30 patients with AH-E diagnosed at our Gunma University Hospital, and located in 3-39-15 Showa-machi, Maebashi, Gunma 371-8511 Japan, and its affiliated hospitals from 2004 to 2015, were studied. We evaluated the detailed medical histories, laboratory examinations and virological features of these participants. RESULTS: Of the 30 patients, 21 patients were men, with a median age of 61 years. Three of these patients had a history of recent oversea travel. A total of 14 patients had eaten raw or undercooked meat/viscera from animals, and two patients had contracted transfusion-transmitted AH-E. Eight patients were immunocompromised, including those with hematological disease, cancer receiving systemic chemotherapy and kidney transplant or connective tissue disease undergoing immunosuppressive medications. The alanine aminotransferase and total bilirubin levels were more significantly reduced in these immunocompromised patients than in the non-immunocompromised patients. Severe thrombocytopenia, an extra-hepatic manifestation of AH-E, occurred in one case. Among the 22 HEV strains whose subgenotype was determined, two were imported strains (1a and 1f), and 11 strains formed four distinct phylogenetic clusters within subgenotype 3b. The remaining nine strains differed from each other by 9.8-22.4%, and were classified into four subgenotypes (3a, 3b, 3e and 3f). CONCLUSION: Markedly divergent HEV strains (3a, 3b, 3e and 3f) were found to circulate in Gunma. Although immunosuppression appears to play a crucial role in establishing chronic sequels, AH-E in eight immunocompromised patients, including transfusion-transmitted HEV infection in two patients, did not become chronic.

Combination Therapy with Ombitasvir/Paritaprevir/Ritonavir for Dialysis Patients Infected with Hepatitis C Virus: A Prospective Multi-Institutional Study.

Hepatitis C virus (HCV) infection is common in dialysis patients worldwide and nosocomial HCV spread within dialysis facilities continues to develop. Combination therapy with daclatasvir and asunaprevir (DCV/ASV) that has proven efficacy for dialysis patients infected with genotype 1b HCV (HCV/1b) has several concerns in Japan. The recently available combination therapy with ombitasvir, paritaprevir, and ritonavir (OBV/PTV/r) is not contraindicated in patients with chronic renal failure and has more safety profile and shorter treatment period than that with DCV/ASV. We evaluated the effects of combination therapy with OBV/PTV/r in four dialysis patients infected with HCV/1b, who were eligible for our study. On-treatment assessments included standard laboratory testing, serum HCV RNA and symptom-directed physical examinations. Three patients had a sustained virological response at 12 weeks after treatment, but one remaining patient had viral breakthrough. Notably, the patient with viral breakthrough had been coinfected with HCV/1b and HCV/2b; namely, HCV/2b with resistance-associated variations was not eradicated by the combination therapy. Among the three patients responsive to the combination therapy, one patient complained of appetite loss and itching, while in another patient the therapy was discontinued due to itching, exacerbation of wamble, and a falling tendency probably due to interaction with valsartan. These AEs were ameliorated or disappeared after the completion of the therapy. The significance of our study is persuasive virological evaluation associated to the combination therapy and reasonable interpretation of AEs. In conclusion, combination therapy with OBV/PTV/r may have promise as an efficacious therapy, but caution regarding AEs should be practiced.

A prospective randomized controlled study of long-term combination therapy using ursodeoxycholic acid and bezafibrate in patients with primary biliary cirrhosis and dyslipidemia.

OBJECTIVES: The aim of this study was to assess the long-term prognosis, efficacy, and safety of combination therapy using ursodeoxycholic acid (UDCA) and bezafibrate (BF) for primary biliary cirrhosis (PBC) patients exhibiting dyslipidemia. METHODS: We performed a prospective, randomized, controlled, multicenter study to compare the long-term clinical results between combination therapy and UDCA monotherapy for patients refractory to UDCA monotherapy. Twenty-seven consecutive PBC patients were enrolled. RESULTS: The median treatment period in the UDCA and UDCA+BF groups was 107 and 110 months, respectively. The serum alkaline phosphatase (ALP) levels and the Mayo risk score in the combination therapy group (mean 290 IU/l and 0.91, respectively) were significantly lower than those in the UDCA monotherapy group (mean 461 IU/l and 1.42, respectively) at 8 years after the beginning of the study (P<0.05). The serum creatinine levels in the combination therapy group (mean 0.94 mg/dl) were significantly higher than those in the UDCA monotherapy group (mean 0.56 mg/dl) at 8 years after the beginning of the study (P<0.05). However, the survival rate was not significantly different between the groups. We observed dose reduction or discontinuation of the administration of BF, but not UDCA, due to renal dysfunction or muscle pain. CONCLUSIONS: Long-term combination therapy significantly improved the serum ALP levels and the Mayo risk score. However, the survival rate was not significantly different between the groups. In addition, long-term combination therapy significantly increased the serum creatinine levels. We should pay close attention to adverse events during this long-term combination therapy.

Expression of amino acid transporters (LAT1, ASCT2 and xCT) as clinical significance in hepatocellular carcinoma.

AIM: Amino acid transporters play an important role in tumor progression and survival of cancer cells. However, the prognostic significance of L-type amino acid transporter 1 (LAT1), system ASC amino acid transporter-2 (ASCT2) and xCT expression in patients with hepatocellular carcinoma (HCC) remains unclear. The aim of this study is to investigate the clinicopathological significance of these amino acid transporters in patients with HCC. METHODS: We examined 84 patients with surgically resected HCC. Tumor sections were stained by immunohistochemistry for LAT1, ASCT2, xCT, 4F2hc/CD98hc (4F2hc), Ki-67 and microvessel density (MVD) determined by CD34. RESULTS: LAT1, 4F2hc, ASCT2 and xCT were positively expressed in 61% (50/84), 77% (65/84), 63% (53/84) and 65% (55/84), respectively. Positive LAT1 expression was significantly associated with 4F2hc expression, Ki-67 and the serum albumin. By univariate analysis, LAT1 expression, disease stage and albumin had a significant relationship with overall survival. Tumor size, disease stage, portal vein invasion, albumin and α-fetoprotein had a significant relationship with progression-free survival. Multivariate analysis confirmed that LAT1 expression is an independent and significant prognostic factor for predicting worse outcome after surgery. CONCLUSION: LAT1 can serve as a significant prognostic marker for predicting negative prognosis after surgery.

[Drug-induced liver injury caused by a dietary supplement (Kin-toki Shoga(®)) made from ginger].

A 70-year-old woman who took a dietary supplement, Kin-toki Shoga(®) made from ginger for peripheral psychroesthesia and numbness, experienced an epigastric sense of incongruity and appetite loss and passed brown urine for 2 months. Although she had stopped taking the supplement, her symptoms had not improved. She was admitted to our hospital because of jaundice and liver dysfunction. After an investigation of causes, she was diagnosed with drug-induced liver injury caused by Kin-toki Shoga(®). Liver dysfunction gradually improved with conservative treatment. She was discharged on the 25th day of illness. Liver biopsy findings were compatible with drug-induced liver injury.

A case of thyroid storm with a markedly elevated level of circulating soluble interleukin-2 receptor complicated by multiple organ failure and disseminated intravascular coagulation syndrome.

Thyroid storm (TS) is a life-threatening endocrine emergency. However, the pathogenesis of TS is poorly understood. A 40-year-old man was admitted to a nearby hospital with body weight loss and jaundice. Five days after a contrasted abdominal computerized tomography (CT) scan, he exhibited high fever and disturbance of consciousness. He was diagnosed with TS originating from untreated Graves' disease and was transferred to the intensive care unit (ICU) of our hospital. The patient exhibited impaired consciousness (E4V1M4 in Glasgow coma scale), high fever (39.3°C), and atrial flutter with a pulse rate 162/min, and was complicated by heart failure, acute hepatic failure, and disseminated intravascular coagulation syndrome (DIC). His circulating level of soluble interleukin-2 receptor (sIL-2R), a serum marker of an activated immune response, was highly elevated (7,416 U/mL, reference range: 135-483). Multiple organ failure (MOF) and DIC were successfully managed by multimodality treatments using inorganized iodide, glucocorticoids, anti-thyroid drugs, beta-blockers, and diuretics as well as an anticoagulant agent and the transfusion of platelet concentrate and fresh frozen plasma. sIL-2R levels gradually decreased during the initial treatment, but were still above the reference range even after thyroidectomy. Mild elevations in serum levels of sIL-2R have previously been correlated with thyroid hormone levels in non-storm Graves' disease. The present study demonstrated, for the first time, that circulating sIL-2R levels could be markedly elevated in TS. The marked increase in sIL-2R levels was speculated to represent an inappropriate generalized immune response that plays an unknown role in the pathogenesis of TS.

Paracrine activation of hepatic CB1 receptors by stellate cell-derived endocannabinoids mediates alcoholic fatty liver.

Alcohol-induced fatty liver, a major cause of morbidity, has been attributed to enhanced hepatic lipogenesis and decreased fat clearance of unknown mechanism. Here we report that the steatosis induced in mice by a low-fat, liquid ethanol diet is attenuated by concurrent blockade of cannabinoid CB1 receptors. Global or hepatocyte-specific CB1 knockout mice are resistant to ethanol-induced steatosis and increases in lipogenic gene expression and have increased carnitine palmitoyltransferase 1 activity, which, unlike in controls, is not reduced by ethanol treatment. Ethanol feeding increases the hepatic expression of CB1 receptors and upregulates the endocannabinoid 2-arachidonoylglycerol (2-AG) and its biosynthetic enzyme diacylglycerol lipase beta selectively in hepatic stellate cells. In control but not CB1 receptor-deficient hepatocytes, coculture with stellate cells from ethanol-fed mice results in upregulation of CB1 receptors and lipogenic gene expression. We conclude that paracrine activation of hepatic CB1 receptors by stellate cell-derived 2-AG mediates ethanol-induced steatosis through increasing lipogenesis and decreasing fatty acid oxidation.

Transforming growth factor-α activates pancreatic stellate cells and may be involved in matrix metalloproteinase-1 upregulation.

The role that transforming growth factor-α (TGF-α) has in chronic pancreatitis and pancreatic cancer has not been fully elucidated. We evaluated the effects of TGF-α on the human pancreatic stellate cell (PSC) line RLT-PSC and primary human PSCs, and the expression levels of TGF-α and metalloproteinase-1 (MMP-1) in human chronic pancreatitis and pancreatic cancer tissues. TGF-α stimulated the proliferation and migration of PSCs. Although the mRNA expression levels of tissue inhibitor of metalloproteinase-1 and α1(I) collagen were unchanged, the mRNA expression levels of MMP-1 increased concomitant with increases in MMP-1 protein levels and collagenase activity. TGF-α-stimulated migration of RLT-PSC cells was partially blocked by tissue inhibitor of metalloproteinase-1 protein and MMP-1 small interfering RNA. MMP-1 was also observed to stimulate the migration of PSCs. TGF-α-induced MMP-1 expression was completely blocked by gefitinib in PSCs. The Ras-ERK and PI3/Akt pathways appear to be involved in the activation of MMP-1 in PSCs. Immunohistochemical analyses showed that MMP-1 expression was significantly increased in the pancreatic interstitial tissues in case of chronic pancreatitis or pancreatic cancer compared with those in case of normal pancreas. In conclusion, TGF-α increased proliferation and migration of PSCs. TGF-α-induced migration of cells may be partly due to upregulation of MMP-1. TGF-α and MMP-1 upregulation may contribute to the pathogenesis of chronic pancreatitis and pancreatic cancer.

Interferon treatment for patients with chronic hepatitis C complicated with chronic renal failure receiving hemodialysis.

BACKGROUND AND AIMS: The Japan Society for Dialysis Therapy established "Guidelines for the Treatment of Hepatitis C Virus Infection in Dialysis Patients." We evaluated the status of HCV infection and the treatment of hemodialysis patients in Gunma prefecture. METHODS: Questionnaires concerning the infection rate, recognition of the guidelines, and treatment status were sent to all 64 hospitals/clinics that had hemodialysis systems in Gunma prefecture. The hepatitis C virus-infected hemodialysis patients who received pegylated interferon (peg-IFN) were analyzed at Gunma University Hospital. RESULTS: The positive rate for hepatitis C virus antibody was 256/2582 hemodialysis patients (9.9%). The positive rate varied between institutions (range 0-40.0%; median 9.0%). All institutes recognized the establishment of the guidelines. Conventional or peg-IFN treatment was being given at 37.5% of the institutions. The other 62.5% institutions answered that they intended to provide the treatment in the future if collaboration with a hepatologist could be arranged. The most common answers regarding the indication for IFN treatment were as follows: few complications, under 60 years of age, more than 10 years of survival expected on hemodialysis. Eighteen patients received peg-IFN treatment. The sustained virological response rate of all patients was 33.3%, 0% in 1b/high viral titer, 50% in genotype 2, and 100% in genotype 2/low viral titer. The sustained virological response rate was worse in the patients with 1b/high viral load and diabetic nephropathy (P < 0.05). CONCLUSIONS: Recognition of the publication of the guidelines was high. However, the number of patients treated with peg-IFN was still low. Further enlightenment and cooperation between hemodialysis teams and hepatologists are therefore needed.

A prospective study of long-term outcomes in female patients with nonalcoholic steatohepatitis using age- and body mass index-matched cohorts.

In patients with nonalcoholic steatohepatitis (NASH), the prevalence of cirrhosis is higher among women than men, and hepatocellular carcinoma (HCC) develops mainly in the cirrhotic stage among women. However, the long-term outcomes in female patients with NASH have not been fully elucidated, and age, gender and BMI were not simultaneously adjusted in previous studies on the prognosis of NASH. To elucidate the outcomes in female patients with NASH, we prospectively compared NASH patients with advanced fibrosis (advanced NASH) with hepatitis C virus-related advanced fibrosis (advanced CHC) patients and NASH patients with mild fibrosis (mild NASH) using study cohorts that were adjusted for body mass index (BMI) in addition to age. The median follow-up period was 92.5 months. Liver-related complication-free survival was significantly reduced in the advanced NASH group compared to the mild NASH group. No liver-related complications developed in the mild NASH group. The overall survival, liver-related complication- and cardiovascular/cerebrovascular disease-free survival were not significantly different between the advanced NASH and CHC groups. Female patients with NASH and advanced fibrosis may have a less favorable prognosis for liver-related complications than the matched cohorts with NASH and mild fibrosis, but may have a similar prognosis to the matched cohorts with CHC.

Inflammation-associated interleukin-6/signal transducer and activator of transcription 3 activation ameliorates alcoholic and nonalcoholic fatty liver diseases in interleukin-10-deficient mice.

UNLABELLED: Alcoholic and nonalcoholic steatohepatitis are characterized by fatty liver plus inflammation. It is generally believed that steatosis promotes inflammation, whereas inflammation in turn aggregates steatosis. Thus, we hypothesized the deletion of interleukin (IL)-10, a key anti-inflammatory cytokine, exacerbates liver inflammation, steatosis, and hepatocellular damage in alcoholic and nonalcoholic fatty liver disease models that were achieved via feeding mice with a liquid diet containing 5% ethanol for 4 weeks or a high-fat diet (HFD) for 12 weeks, respectively. IL-10 knockout (IL-10(-/-)) mice and several other strains of genetically modified mice were generated and used. Compared with wild-type mice, IL-10(-/-) mice had greater liver inflammatory response with higher levels of IL-6 and hepatic signal transducer and activator of transcription 3 (STAT3) activation, but less steatosis and hepatocellular damage after alcohol or HFD feeding. An additional deletion of IL-6 or hepatic STAT3 restored steatosis and hepatocellular damage but further enhanced liver inflammatory response in IL-10(-/-) mice. In addition, the hepatic expression of sterol regulatory element-binding protein 1 and key downstream lipogenic proteins and enzymes in fatty acid synthesis were down-regulated in IL-10(-/-) mice. Conversely, IL-10(-/-) mice displayed enhanced levels of phosphorylated adenosine monophosphate-activated protein kinase and its downstream targets including phosphorylated acetyl-coenzyme A carboxylase and carnitine palmitoyltransferase 1 in the liver. Such dysregulations were corrected in IL-10(-/-) IL-6(-/-) or IL-10(-/-) STAT3(Hep-/-) double knockout mice. CONCLUSION: IL-10(-/-) mice are prone to liver inflammatory response but are resistant to steatosis and hepatocellular damage induced by ethanol or HFD feeding. Resistance to steatosis in these mice is attributable to elevation of inflammation-associated hepatic IL-6/STAT3 activation that subsequently down-regulates lipogenic genes but up-regulates fatty acid oxidation-associated genes in the liver.

Optimal follow-up time to determine the sustained virological response in patients with chronic hepatitis C receiving pegylated-interferon and ribavirin.

BACKGROUND AND AIM: This study evaluated whether the assessment of hepatitis C virus (HCV)-RNA at 12 weeks (FW+12) post-treatment follow-up was as applicable as FW+24 to evaluate sustained virological response (SVR) using the highly sensitive real-time polymerase chain reaction (PCR) HCV assay. METHODS AND RESULTS: Two hundred and twenty-two patients with chronic hepatitis C were included in this study. Pegylated interferon (Peg-IFN) and ribavirin were administered for 24-72 weeks based on the genotype and viral load. Serum HCV-RNA was measured using real-time PCR at pretreatment, the end of treatment, FW+4, FW+8, FW+12, FW+16, FW+20 and FW+24. Two hundred patients had a virological response at the end of treatment. One hundred and forty-eight of 200 (74.0%) patients with a virological response at the end of treatment had an SVR at the FW+24. The positive predictive value (PPV) to identify patients with SVR at FW+4, FW+8, FW+12 was 87.1, 96.1, 98.0%, respectively. The viral load showed a reversion to the basal level as early as 8 weeks in relapse patients. There were only three patients who relapsed after FW+12 and all three of these patients were females with genotype Ib and a high viral load. CONCLUSION: The assessment of serum HCV-RNA FW+12, using the highly sensitive real-time PCR assay, is almost as effective as FW+24 to predict SVR. However, there are false negatives in female patients with a high viral load of genotype Ib when the SVR is predicted by FW+12. The current standard with FW+24 is reasonable, but the assessment of serum HCV-RNA FW+12 may be effective in most patients.

Adolescents with chronic hepatitis C might be good candidates for direct-acting antiviral therapy.

Three Japanese adolescents with chronic hepatitis C were treated by direct-acting antivirals (DAAs). No adverse events or laboratory abnormalities were observed during and after DAA therapy, and a sustained virological response was achieved in all cases. The emotional functioning of the patients and their mothers were improved after DAA therapy.

Constitutive active/androstane receptor promotes hepatocarcinogenesis in a mouse model of non-alcoholic steatohepatitis.

The nuclear receptor constitutive active/androstane receptor (CAR) acts as a sensor of toxic byproducts derived from the endogenous metabolism and exogenous chemicals. We previously reported that CAR is responsible for exacerbating hepatic injury and fibrosis in a dietary model of non-alcoholic steatohepatitis (NASH) via upregulation of lipid peroxidation. In this study, we investigated the pathological roles of the CAR in the development of hepatocellular carcinoma in NASH model. CAR+/+ and CAR-/- mice were fed methionine- and choline-deficient (MCD) diet after tumor initiation with a single dose of the genotoxic carcinogen diethylnitrosamine (DEN) at 2 weeks of age. Interestingly, the MCD diet dramatically promoted DEN-induced hepatocarcinogenesis in CAR+/+ mice. However, the deletion of CAR leads to a significantly lower tumor incidence and smaller tumor diameter. Hepatocytes of MCD-treated-CAR+/+ mice showed a significantly higher staining frequency of Ki-67, a marker of cell proliferation, and exhibited a higher expression of c-Myc and FoxM1 transcripts compared with MCD-treated CAR-/- mice. Immunohistochemistry revealed the nuclear translocation of CAR thus suggesting that the activation of CAR signaling increased in the hepatocytes of CAR+/+ mice fed MCD diet. In addition, in vitro experiments using the CAR stably expressed cell line with TCPOBOP have suggested that CAR activation directly leads to cell proliferation. Survival was significantly lower in the CAR+/+ mice fed the MCD diet in comparison with the CAR-/- mice. Taken together, these results suggest that CAR may therefore play a critical role in the hepatocarcinogenesis of the murine NASH model via the upregulation of cell proliferation.

Interplay of hepatic and myeloid signal transducer and activator of transcription 3 in facilitating liver regeneration via tempering innate immunity.

UNLABELLED: Liver regeneration triggered by two-thirds partial hepatectomy is accompanied by elevated hepatic levels of endotoxin, which contributes to the regenerative process, but liver inflammation and apoptosis remain paradoxically limited. Here, we show that signal transducer and activator of transcription 3 (STAT3), an important anti-inflammatory signal, is activated in myeloid cells after partial hepatectomy and its conditional deletion results in an enhanced inflammatory response. Surprisingly, this is accompanied by an improved rather than impaired regenerative response with increased hepatic STAT3 activation, which may contribute to the enhanced liver regeneration. Indeed, conditional deletion of STAT3 in both hepatocytes and myeloid cells results in elevated activation of STAT1 and apoptosis of hepatocytes, and a dramatic reduction in survival after partial hepatectomy, whereas additional global deletion of STAT1 protects against these effects. CONCLUSION: An interplay of myeloid and hepatic STAT3 signaling is essential to prevent liver failure during liver regeneration through tempering a strong innate inflammatory response mediated by STAT1 signaling.

Dissociation between liver inflammation and hepatocellular damage induced by carbon tetrachloride in myeloid cell-specific signal transducer and activator of transcription 3 gene knockout mice.

UNLABELLED: Liver injury is associated with inflammation, which is generally believed to accelerate the progression of liver diseases; however, clinical data show that inflammation does not always correlate with hepatocelluar damage in some patients. Investigating the cellular mechanisms underlying these events using an experimental animal model, we show that inflammation may attenuate liver necrosis induced by carbon tetrachloride (CCl(4)) in myeloid-specific signal transducer and activator of transcription 3 (STAT3) knockout mice. As an important anti-inflammatory signal, conditional deletion of STAT3 in myeloid cells results in markedly enhanced liver inflammation after CCl(4) injection. However, these effects are also accompanied by reduced liver necrosis, correlating with elevated serum interleukin-6 (IL-6) and hepatic STAT3 activation. An additional deletion of STAT3 in hepatocytes in myeloid-specific STAT3 knockout mice restored hepatic necrosis but decreased liver inflammation. CONCLUSION: Inflammation-mediated STAT3 activation attenuates hepatocellular injury induced by CCl(4) in myeloid-specific STAT3 knockout mice, suggesting that inflammation associated with a predominance of hepatoprotective cytokines that activate hepatic STAT3 may reduce rather than accelerate hepatocellular damage in patients with chronic liver diseases.

Transforming growth factor-α attenuates hepatic fibrosis: possible involvement of matrix metalloproteinase-1.

BACKGROUND: The effect of transforming growth factor (TGF)-α on fibrosis varies between cell types and the role of TGF-α in hepatic fibrosis has not been fully elucidated. METHODS: We examined the effect of TGF-α on hepatic fibrosis using TGF-α-expressing transgenic mice fed a methionine- and choline-deficient (MCD) diet and human hepatic stellate cells (HSCs) line LX-2, rat and human primary HSCs. RESULTS: Although the expression levels of the tissue inhibitor of metalloproteinases-1 and α1(I) collagen mRNA were unchanged, feeding the TGF-α transgenic mice the MCD diet resulted in greater expression of the murine functional analogue of matrix metalloproteinase-1 (MMP-1), MMP-13 mRNA and protein and attenuated hepatic fibrosis compared with wild-type mice. TGF-α overexpression did not affect the extent of the steatosis, oxidative stress and hepatic inflammation in the MCD diet-fed mice. The effect of TGF-α on the fibrogenic and anti-fibrogenic gene expressions varied between cell types in vitro. TGF-α increased MMP-1 mRNA expressions that were completely blocked by gefitinib in LX-2 cells. The extracellular signal-regulated kinase (ERK) 1/2, c-Jun N-terminal kinase and p38 pathways were involved in MMP-1 mRNA expression in LX-2 cells. Although TGF-α increased the phosphorylation of p38, the p38 inhibitor activated the RAS-ERK pathway and increased TGF-α-induced MMP-1 mRNA expression, which suggested that there may be a crosstalk between the RAS-ERK and the p38 pathways in LX-2 cells. CONCLUSIONS: The TGF-α may attenuate hepatic fibrosis in part because of upregulation of the expression of MMP-1. The balance between fibrogenic and anti-fibrogenic gene expression and between the activity of the RAS-ERK and the p38 pathways may be crucial for the fibrotic process.

Molecular mechanisms of alcoholic liver disease: innate immunity and cytokines.

Alcohol consumption is a predominant etiological factor in the pathogenesis of chronic liver diseases worldwide, causing fatty liver, alcoholic hepatitis, fibrosis/cirrhosis, and hepatocellular carcinoma. In the past few decades, significant progress has been made in our understanding of the molecular mechanisms underlying alcoholic liver injury. Activation of innate immunity components such as Kupffer cells, LPS/TLR4, and complements in response to alcohol exposure plays a key role in the development and progression of alcoholic liver disease (ALD). LPS activation of Kupffer cells also produces IL-6 and IL-10 that may play a protective role in ameliorating ALD. IL-6 activates signal transducer and activator of transcription 3 (STAT3) in hepatocytes and sinusoidal endothelial cells, while IL-10 activates STAT3 in Kupffer cells/macrophages, subsequently protecting against ALD. In addition, alcohol consumption also inhibits some components of innate immunity such as natural killer (NK) cells, a type of cells that play key roles in anti-viral, anti-tumor, and anti-fibrotic defenses in the liver. Ethanol inhibition of NK cells likely contributes significantly to the pathogenesis of ALD. Understanding the roles of innate immunity and cytokines in alcoholic liver injury may provide insight into novel therapeutic targets in the treatment of alcoholic liver disease.