Hepatic Mitochondrial SAB Deletion or Knockdown Alleviates Diet-Induced Metabolic Syndrome, Steatohepatitis, and Hepatic Fibrosis.

BACKGROUND AND AIMS: The hepatic mitogen-activated protein kinase (MAPK) cascade leading to c-Jun N-terminal kinase (JNK) activation has been implicated in the pathogenesis of nonalcoholic fatty liver (NAFL)/NASH. In acute hepatotoxicity, we previously identified a pivotal role for mitochondrial SH3BP5 (SAB; SH3 homology associated BTK binding protein) as a target of JNK, which sustains its activation through promotion of reactive oxygen species production. Therefore, we assessed the role of hepatic SAB in experimental NASH and metabolic syndrome. APPROACH AND RESULTS: In mice fed high-fat, high-calorie, high-fructose (HFHC) diet, SAB expression progressively increased through a sustained JNK/activating transcription factor 2 (ATF2) activation loop. Inducible deletion of hepatic SAB markedly decreased sustained JNK activation and improved systemic energy expenditure at 8 weeks followed by decreased body fat at 16 weeks of HFHC diet. After 30 weeks, mice treated with control-antisense oligonucleotide (control-ASO) developed steatohepatitis and fibrosis, which was prevented by Sab-ASO treatment. Phosphorylated JNK (p-JNK) and phosphorylated ATF2 (p-ATF2) were markedly attenuated by Sab-ASO treatment. After 52 weeks of HFHC feeding, control N-acetylgalactosamine antisense oligonucleotide (GalNAc-Ctl-ASO) treated mice fed the HFHC diet exhibited progression of steatohepatitis and fibrosis, but GalNAc-Sab-ASO treatment from weeks 40 to 52 reversed these findings while decreasing hepatic SAB, p-ATF2, and p-JNK to chow-fed levels. CONCLUSIONS: Hepatic SAB expression increases in HFHC diet-fed mice. Deletion or knockdown of SAB inhibited sustained JNK activation and steatohepatitis, fibrosis, and systemic metabolic effects, suggesting that induction of hepatocyte Sab is an important driver of the interplay between the liver and the systemic metabolic consequences of overfeeding. In established NASH, hepatocyte-targeted GalNAc-Sab-ASO treatment reversed steatohepatitis and fibrosis.

IgG:IgM Ratios of Liver Plasma Cells Reveal Similar Phenotypes of Primary Biliary Cholangitis With and Without Features of Autoimmune Hepatitis.

Within the spectrum of autoimmune liver diseases, there are patients who manifest features of more than one disease, which was previously identified as having overlap syndrome1,2 and is now referred to as variant syndromes. The most common variant syndrome is between primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH). Typically, AIH presents with elevated serum immunoglobulin (Ig) G, whereas PBC is associated with elevated serum IgM.3,4 Previous studies have suggested that plasma cells in liver biopsies of AIH patients are predominantly IgG+, whereas in PBC, there is an abundance of IgM+ cells.5,6 We wanted to determine the immunostaining pattern for IgG and IgM of liver plasma cells among Hispanic patients in Los Angeles with features of both PBC-AIH compared with those with PBC or AIH alone.

Detection of Occult Hepatitis C Virus Infection in Patients Who Achieved a Sustained Virologic Response to Direct-Acting Antiviral Agents for Recurrent Infection After Liver Transplantation.

Occult infection with hepatitis C virus (HCV) is defined as the presence of the HCV genome in either liver tissue or peripheral blood monocytes, despite constant negative results from tests for HCV RNA in serum. We investigated whether patients who maintained a sustained virologic response 12 weeks after therapy (SVR12) with direct-acting antiviral (DAA) agents for recurrent HCV infection after liver transplantation had occult HCV infections. We performed a prospective study of 134 patients with recurrent HCV infection after liver transplantation who were treated with DAAs, with or without ribavirin, from 2014 through 2016 (129 patients achieved an SVR12). In >10% of the patients who achieved SVR12 (n = 14), serum levels of aminotransferases did not normalize during or after DAA therapy, or they normalized transiently but then increased sharply after DAA therapy. Of these 14 patients, 9 were assessed for occult HCV infection by reverse transcription quantitative polymerase chain reaction. This analysis revealed that 55% of these patients (n = 5) had an occult infection, with the detection of negative strand viral genome, indicating viral replication. These findings indicate the presence of occult HCV infection in some patients with abnormal levels of serum aminotransferases, despite SVR12 to DAAs for HCV infection after liver transplantation.

Liver-specific knockout of GRP94 in mice disrupts cell adhesion, activates liver progenitor cells, and accelerates liver tumorigenesis.

UNLABELLED: Liver cancer is one of the most common solid tumors, with poor prognosis and high mortality. Mutation or deletion of the tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is strongly correlated with human liver cancer. Glucose-regulated protein 94 (GRP94) is a major endoplasmic reticulum (ER) chaperone protein, but its in vivo function is still emerging. To study the role of GRP94 in maintaining liver homeostasis and tumor development, we created two liver-specific knockout mouse models with the deletion of Grp94 alone, or in combination with Pten, using the albumin-cre system. We demonstrated that while deletion of GRP94 in the liver led to hyperproliferation of liver progenitor cells, deletion of both GRP94 and PTEN accelerated development of liver tumors, including both hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC), suggestive of progenitor cell origin. Furthermore, at the premalignant stage we observed disturbance of cell adhesion proteins and minor liver injury. When GRP94 was deleted in PTEN-null livers, ERK was selectively activated. CONCLUSION: GRP94 is a novel regulator of cell adhesion, liver homeostasis, and tumorigenesis.

Innate and adaptive immune cell interaction drives inflammasome activation and hepatocyte apoptosis in murine liver injury from immune checkpoint inhibitors.

Immune checkpoints (CTLA4 & PD-1) are inhibitory pathways that block aberrant immune activity and maintain self-tolerance. Tumors co-opt these checkpoints to avoid immune destruction. Immune checkpoint inhibitors (ICIs) activate immune cells and restore their tumoricidal potential, making them highly efficacious cancer therapies. However, immunotolerant organs such as the liver depend on these tolerogenic mechanisms, and their disruption with ICI use can trigger the unintended side effect of hepatotoxicity termed immune-mediated liver injury from ICIs (ILICI). Learning how to uncouple ILICI from ICI anti-tumor activity is of paramount clinical importance. We developed a murine model to recapitulate human ILICI using CTLA4+/- mice treated with either combined anti-CTLA4 + anti-PDL1 or IgG1 + IgG2. We tested two forms of antisense oligonucleotides to knockdown caspase-3 in a total liver (parenchymal and non-parenchymal cells) or in a hepatocyte-specific manner. We also employed imaging mass cytometry (IMC), a powerful multiplex modality for immunophenotyping and cell interaction analysis in our model. ICI-treated mice had significant evidence of liver injury. We detected cleaved caspase-3 (cC3), indicating apoptosis was occurring, as well as Nod-like receptor protein 3 (NLRP3) inflammasome activation, but no necroptosis. Total liver knockdown of caspase-3 worsened liver injury, and induced further inflammasome activation, and Gasdermin-D-mediated pyroptosis. Hepatocyte-specific knockdown of caspase-3 reduced liver injury and NLRP3 inflammasome activation. IMC-generated single-cell data for 77,692 cells was used to identify 22 unique phenotypic clusters. Spatial analysis revealed that cC3+ hepatocytes had significantly closer interactions with macrophages, Kupffer cells, and NLRP3hi myeloid cells than other cell types. We also observed zones of three-way interaction between cC3+ hepatocytes, CD8 + T-cells, and macrophages. Our work is the first to identify hepatocyte apoptosis and NLRP3 inflammasome activation as drivers of ILICI. Furthermore, we report that the interplay between adaptive and innate immune cells is critical to hepatocyte apoptosis and ILICI.

Role of differentiation of liver sinusoidal endothelial cells in progression and regression of hepatic fibrosis in rats.

BACKGROUND & AIMS: Capillarization, characterized by loss of differentiation of liver sinusoidal endothelial cells (LSECs), precedes the onset of hepatic fibrosis. We investigated whether restoration of LSEC differentiation would normalize crosstalk with activated hepatic stellate cells (HSC) and thereby promote quiescence of HSC and regression of fibrosis. METHODS: Rat LSECs were cultured with inhibitors and/or agonists and examined by scanning electron microscopy for fenestrae in sieve plates. Cirrhosis was induced in rats using thioacetamide, followed by administration of BAY 60-2770, an activator of soluble guanylate cyclase (sGC). Fibrosis was assessed by Sirius red staining; expression of α-smooth muscle actin was measured by immunoblot analysis. RESULTS: Maintenance of LSEC differentiation requires vascular endothelial growth factor-A stimulation of nitric oxide-dependent signaling (via sGC and cyclic guanosine monophosphate) and nitric oxide-independent signaling. In rats with thioacetamide-induced cirrhosis, BAY 60-2770 accelerated the complete reversal of capillarization (restored differentiation of LSECs) without directly affecting activation of HSCs or fibrosis. Restoration of differentiation to LSECs led to quiescence of HSCs and regression of fibrosis in the absence of further exposure to BAY 60-2770. Activation of sGC with BAY 60-2770 prevented progression of cirrhosis, despite continued administration of thioacetamide. CONCLUSIONS: The state of LSEC differentiation plays a pivotal role in HSC activation and the fibrotic process.

Hepatic damage caused by long-term high cholesterol intake induces a dysfunctional restorative macrophage population in experimental NASH.

Excessive dietary cholesterol is preferentially stored in the liver, favoring the development of nonalcoholic steatohepatitis (NASH), characterized by progressive hepatic inflammation and fibrosis. Emerging evidence indicates a critical contribution of hepatic macrophages to NASH severity. However, the impact of cholesterol on these cells in the setting of NASH remains elusive. Here, we demonstrate that the dietary cholesterol content directly affects hepatic macrophage global gene expression. Our findings suggest that the modifications triggered by prolonged high cholesterol intake induce long-lasting hepatic damage and support the expansion of a dysfunctional pro-fibrotic restorative macrophage population even after cholesterol reduction. The present work expands the understanding of the modulatory effects of cholesterol on innate immune cell transcriptome and may help identify novel therapeutic targets for NASH intervention.

Epigenetic profiling of somatic tissues from human autopsy specimens identifies tissue- and individual-specific DNA methylation patterns.

DNA methylation is known to be associated with cell differentiation, aging, disease and cancer. There exists an expanding base of knowledge regarding tissue-specific DNA methylation, but we have little information about person-specific DNA methylation. Here, we analyze the DNA methylation patterns of multiple tissues from multiple individuals using a high-throughput quantitative assay of genome-wide DNA methylation, namely the Illumina GoldenGate BeadArray. DNA methylation patterns were largely conserved across 11 different tissues (r = 0.852) and across six individuals (r = 0.829), and we found that DNA was highly methylated in non-CpG islands and/or CpG sites that are not occupied by either H3K4me3 or H3K27me3 (P < 0.05). Finally, we found that the Illumina GoldenGate assay features a large number of probes (265/1505 probes, 17.6%) that contain single-nucleotide polymorphisms, which may interfere with DNA methylation analyses in genome-wide studies.

Expansion of hepatic tumor progenitor cells in Pten-null mice requires liver injury and is reversed by loss of AKT2.

BACKGROUND & AIMS: The tumor suppressor PTEN inhibits AKT2 signaling; both are aberrantly expressed in liver tumors. We investigated how PTEN and AKT2 regulate liver carcinogenesis. Loss of PTEN leads to spontaneous development of liver tumors from progenitor cells. We investigated how the loss of PTEN activates liver progenitor cells and induces tumorigenesis. METHODS: We studied mice with liver-specific disruptions in Pten and the combination of Pten and Akt2 to investigate mechanisms of liver carcinogenesis. RESULTS: PTEN loss leads to hepatic injury and establishes selective pressure for tumor-initiating cells (TICs), which proliferate to form mixed-lineage tumors. The Pten-null mice had increasing levels of hepatic injury before proliferation of hepatic progenitors. Attenuation of hepatic injury by deletion of Akt2 reduced progenitor cell proliferation and delayed tumor development. In Pten/Akt2-null mice given 3,5-diethoxycarbonyl-1,4 dihydrocollidine (DDC), we found that the primary effect of AKT2 loss was attenuation of hepatic injury and not inhibition of progenitor-cell proliferation in response to injury. CONCLUSIONS: Liver carcinogenesis in Pten-null mice requires not only the transformation of TICs but selection pressure from hepatic injury and cell death, which activates TICs. Further research is required to elucidate the mechanism for hepatic injury and its relationship with TIC activation.

The critical role of AKT2 in hepatic steatosis induced by PTEN loss.

Insulin signaling in the liver leads to accumulation of phosphatidylinositol (3,4,5)-trisphosphate (PIP3). Deletion of the phosphatase Pten (phosphatase and tensin homologue deleted on chromosome 10) reduces PIP3 levels and leads to fatty liver development. The purpose of this study was to investigate the mechanisms underlying lipogenesis that result from PIP3 accumulation using liver Pten-deletion mice. To explore the role of AKT2, the major liver AKT isoform in steatosis induced by deletion of Pten, we created mice lacking both Pten and Akt2 in hepatocytes and compared the effect of deleting Akt2 and Pten in the double mutants to the Pten deletion mice alone. Hepatic lipid accumulation was significantly reduced in mice lacking both PTEN and AKT2, as compared with Pten mutant mice alone. This effect was due to the role of AKT2 in maintaining expression of genes involved in de novo lipogenesis. We showed that lipid accumulation in the double mutant hepatocytes was partially reversed by expression of constitutive active FOXO1, a transcription factor downstream of AKT not dependent on inhibition of atypical protein kinase C. In summary, this study delineated regulation of lipid metabolism by PI3K signaling pathway by showing that AKT mediates PIP3 accumulation (mimicked by PTEN loss) induced lipid deposition in the liver and provided an important molecular mechanism for insulin-regulated hepatic lipogenesis.

Bone marrow progenitor cells repair rat hepatic sinusoidal endothelial cells after liver injury.

BACKGROUND & AIMS: Damage to hepatic sinusoidal endothelial cells (SECs) initiates sinusoidal obstruction syndrome (SOS), which is most commonly a consequence of myeloablative chemoirradiation or ingestion of pyrrolizidine alkaloids such as monocrotaline (Mct). This study examines whether SECs are of bone marrow origin, whether bone marrow repair can be a determinant of severity of liver injury, and whether treatment with progenitor cells is beneficial. METHODS: Mct-treated female rats received infusion of male whole bone marrow or CD133(+) cells at the peak of sinusoidal injury. The Y chromosome was identified in isolated SECs by fluorescent in situ hybridization. Bone marrow suppression was induced by irradiation of both lower extremities with shielding of the abdomen. RESULTS: SECs in uninjured liver have both hematopoietic (CD45, CD33) and endothelial (CD31) markers. After Mct-induced SOS, infusion of bone marrow-derived CD133(+) progenitor cells replaces more than one quarter of SECs. All CD133(+) cells recovered from the SEC fraction after injury are CD45(+). CD133(+)/CD45(+) progenitors also repaired central vein endothelium. Mct suppresses CD133(+)/CD45(+) progenitors in bone marrow by 50% and in the circulation by 97%. Irradiation-induced bone marrow suppression elicited SOS from a subtoxic dose of Mct, whereas infusion of bone marrow during the necrotic phase of SOS nearly eradicates histologic features of SOS. CONCLUSIONS: SECs have both hematopoietic and endothelial markers. Bone marrow-derived CD133(+)/CD45(+) progenitors replace SECs and central vein endothelial cells after injury. Toxicity to bone marrow progenitors impairs repair and contributes to the pathogenesis of SOS, whereas timely infusion of bone marrow has therapeutic benefit.

S-adenosylmethionine in the chemoprevention and treatment of hepatocellular carcinoma in a rat model.

UNLABELLED: Hepatocellular carcinoma (HCC) remains a common cancer worldwide that lacks effective chemoprevention or treatment. Chronic liver disease often leads to impaired hepatic S-adenosylmethionine (SAMe) biosynthesis, and mice with SAMe deficiency develop HCC spontaneously. SAMe is antiapoptotic in normal hepatocytes but proapoptotic in cancerous hepatocytes. The present study investigated SAMe's effectiveness in prevention and treatment of HCC. Two weeks after injecting 2.5 million H4IIE cells into the liver parenchyma of ACI rats, they typically form a 1-cm tumor. When SAMe (150 mg/kg/day) was delivered through continuous intravenous infusion, hepatic SAMe levels reached 0.7 mM (over 10-fold) 24 hours later. This regimen, started 1 day after injecting H4IIE cells and continued for 10 days, was able to reduce tumor establishment and growth. However, if intravenous SAMe was started after HCC had already developed, it was ineffective in reducing tumor growth for 24 days. Although plasma SAMe levels remained elevated, hepatic SAMe levels were minimally increased (30% higher). Chronic SAMe administration led to induction of hepatic methyltransferases, which prevented SAMe accumulation. To see if SAMe's preventive effect on tumor establishment involves angiogenesis, the effect of SAMe on angiogenesis genes was studied. SAMe treatment of H4IIE cells altered the expression of several genes with the net effect of inhibiting angiogenesis. These changes were confirmed at the protein level and functionally in human umbilical vein endothelial cells. CONCLUSION: SAMe is effective in preventing HCC establishment but ineffective in treating established HCC because of induction of hepatic methyltransferases, which prevents SAMe level to reach high enough to kill liver cancer cells. SAMe's chemopreventive effect may be related to its proapoptotic action and its ability to inhibit angiogenesis.

Prevention of hepatic fibrosis in a murine model of metabolic syndrome with nonalcoholic steatohepatitis.

The endocannabinoid pathway plays an important role in the regulation of appetite and body weight, hepatic lipid metabolism, and fibrosis. Blockade of the endocannabinoid receptor CB1 with SR141716 promotes weight loss, reduces hepatocyte fatty acid synthesis, and is antifibrotic. D-4F, an apolipoprotein A-1 mimetic with antioxidant properties, is currently in clinical trials for the treatment of atherosclerosis. C57BL/6J mice were fed a high-fat diet for 7 months, followed by a 2.5-month treatment with either SR141716 or D-4F. SR141716 markedly improved body weight, liver weight, serum transaminases, insulin resistance, hyperglycemia, hypercholesterolemia, hyperleptinemia, and oxidative stress, accompanied by the significant prevention of fibrosis progression. D-4F improved hypercholesterolemia and hyperleptinemia without improvement in body weight, steatohepatitis, insulin resistance, or oxidative stress, and yet, there was significant prevention of fibrosis. D-4F prevented culture-induced activation of stellate cells in vitro. In summary, C57BL/6J mice given a high-fat diet developed features of metabolic syndrome with nonalcoholic steatohepatitis and fibrosis. Both SR141716 and D-4F prevented progression of fibrosis after onset of steatohepatitis, ie, a situation comparable to a common clinical scenario, with D-4F seeming to have a more general antifibrotic effect. Either compound therefore has the potential to be of clinical benefit.

Niacin-Induced Anicteric Microvesicular Steatotic Acute Liver Failure.

Niacin (vitamin B3) is available as a prescription medication and over-the-counter supplement. Although it is well known for its vasodilatory effect, it has also been associated with mild hepatotoxicity and, rarely, acute liver failure. We present the case of a 74-year-old Hispanic woman who developed acute liver failure (anicteric encephalopathy and coagulopathy) after her home dose of immediate-release niacin was replaced with an extended-release formulation during an inpatient hospital stay. This is the first reported case of niacin toxicity associated with a histopathologic finding of diffuse microvesicular steatosis. This unique phenotype strongly implicates mitochondrial impairment as a mechanism of niacin-induced hepatotoxicity.

Lack of increases in methylation at three CpG-rich genomic loci in non-mitotic adult tissues during aging.

BACKGROUND: Cell division occurs during normal human development and aging. Despite the likely importance of cell division to human pathology, it has been difficult to infer somatic cell mitotic ages (total numbers of divisions since the zygote) because direct counting of lifetime numbers of divisions is currently impractical. Here we attempt to infer relative mitotic ages with a molecular clock hypothesis. Somatic genomes may record their mitotic ages because greater numbers of replication errors should accumulate after greater numbers of divisions. Mitotic ages will vary between cell types if they divide at different times and rates. METHODS: Age-related increases in DNA methylation at specific CpG sites (termed "epigenetic molecular clocks") have been previously observed in mitotic human epithelium like the intestines and endometrium. These CpG rich sequences or "tags" start unmethylated and potentially changes in methylation during development and aging represent replication errors. To help distinguish between mitotic versus time-associated changes, DNA methylation tag patterns at 8-20 CpGs within three different genes, two on autosomes and one on the X-chromosome were measured by bisulfite sequencing from heart, brain, kidney and liver of autopsies from 21 individuals of different ages. RESULTS: Levels of DNA methylation were significantly greater in adult compared to fetal or newborn tissues for two of the three examined tags. Consistent with the relative absence of cell division in these adult tissues, there were no significant increases in tag methylation after infancy. CONCLUSION: Many somatic methylation changes at certain CpG rich regions or tags appear to represent replication errors because this methylation increases with chronological age in mitotic epithelium but not in non-mitotic organs. Tag methylation accumulates differently in different tissues, consistent with their expected genealogies and mitotic ages. Although further studies are necessary, these results suggest numbers of divisions and ancestry are at least partially recorded by epigenetic replication errors within somatic cell genomes.

Hepatic angiosarcoma with clinical and histological features of Kasabach-Merritt syndrome.

Hepatic angiosarcoma is a mesenchymal tumor originating from liver sinusoidal endothelial cells. It is an extremely rare malignant neoplasm accounting for less than 1% of primary malignant liver tumors. The deregulated coagulopathy that can be seen in hepatic angiosarcoma fulfills the clinical diagnostic criteria of disseminated intravascular coagulation. However, the mechanism that governs this coagulopathy has been poorly understood. This case report provides histological evidence of the consumption of coagulation factors along with trapped platelets occurring within the tumor, which is the foundation for the concept of Kasabach-Merritt syndrome (KMS). KMS is characterized by thrombocytopenia and hyperconsumption of coagulation factors within a vascular tumor. However, KMS associated with angiosarcoma has not been well recognized. This case report describes, for the first time, the histological evidence of KMS that occurred in an extremely rare mesenchymal malignant tumor of the liver.

Prediction of histologic alcoholic hepatitis based on clinical presentation limits the need for liver biopsy.

The clinical presentation of alcoholic hepatitis (AH) can be mimicked by other alcoholic liver diseases. The aim of this study was to identify clinical features that predict AH on liver biopsy. Biopsies from patients hospitalized for presumed severe AH were used to identify a derivation cohort (101 patients) and validation cohort (71 patients). Using histologic scores for hepatocyte ballooning, Mallory-Denk bodies, and lobular inflammation, 95 patient biopsies (55%) were classified as definite AH, 55 (32%) as possible AH, and 22 (13%) as no AH. Survival was similar among the groups, but mortality was significantly increased for patients with fatty change ≤50% on initial liver biopsy. An analysis limited to uninfected patients with definite AH or no AH in the derivation cohort identified a greater leukocyte count at admission and radiographic evidence of liver surface nodularity as independent predictors of definite AH on biopsy (P < 0.05). In the derivation cohort, the leukocyte count thresholds for ensuring 100% specificity for diagnosing definite AH were 10 × 109/L if the liver surface was nodular and 14 × 109/L if the liver surface was smooth, with a sensitivity of 76% and an area under the receiver operator characteristic curve of 0.88. In the validation cohort, these thresholds had a specificity of 86%, a sensitivity of 59%, and an area under the receiver operator characteristic curve of 0.72. Conclusion: The combination of an elevated leukocyte count and a nodular liver surface in the absence of active infection retrospectively identified patients with a high likelihood of histologic AH for whom liver biopsy may not be necessary. For patients with suspected severe AH who do not fulfill these criteria, liver biopsy is important to exclude other variants of alcoholic liver disease. (Hepatology Communications 2017;1:1070-1084).

Do type and duration of antiretroviral therapy attenuate liver fibrosis in HIV-hepatitis C virus-coinfected patients?

BACKGROUND: This study aimed to determine whether type and duration of therapy for human immunodeficiency virus (HIV) infection attenuates liver fibrosis in patients with HIV and hepatitis C virus (HCV) coinfection. METHODS: Patients with HCV monoinfection (group 1) and HIV-HCV coinfection were retrospectively selected; the latter patients were classified into the following 3 groups: group 2, patients who received no therapy or only nucleoside reverse-transcriptase inhibitors (NRTIs); group 3, those who received highly active antiretroviral therapy (HAART); and group 4, those who initially received NRTIs followed by HAART. Fibrosis stage (scale, 0-6) and necroinflammatory score (scale, 0-18) were assessed according to the Ishak system. Data are presented as mean +/- standard deviation. RESULTS: Three hundred eighty-one patients (296 HCV-monoinfected patients and 85 HIV-HCV-coinfected patients) were recruited. The durations of HIV therapy before liver biopsy was performed for groups 2, 3, and 4 were 3.8 +/- 2.8, 3.3 +/- 1.8, and 6.6 +/- 2.2 years. The time from HIV diagnosis to HAART initiation was shorter for group 3 than for group 4 (9.1 +/- 7.3 vs. 34.1 +/- 13.1 months; P < .0001). Groups 1 and 3 had similar fibrosis stages (3.1 +/- 2 vs. 3.4 +/- 2.4), rates of fibrosis progression (0.13 +/- 0.09 vs. 0.16 +/- 0.11 per year), and necroinflammatory scores (6.1 +/- 1.8 vs. 6.1 +/- 2.0). Groups 2 and 4 had significantly more-advanced liver disease, as determined by fibrosis stage (4.6 +/- 1.8 vs. 4.3 +/- 2.0; P < .0009), rate of fibrosis progression (0.24 +/- 0.11 vs. 0.20 +/- 0.10 per year; P < .0001), and prevalence of cirrhosis (68% vs. 55%; P < .006), compared with group 1. CONCLUSIONS: HIC-HCV-coinfected subjects who receive HAART as their sole form of therapy have liver histology findings comparable to those for HCV-monoinfected patients. A similar degree of benefit is not observed for HIV-HCV-coinfected patients who receive no therapy, NRTIs, or HAART after NRTIs, despite having a longer duration of therapy.

Spontaneous oxidative stress and liver tumors in mice lacking methionine adenosyltransferase 1A.

In mammals, methionine metabolism occurs mainly in the liver via methionine adenosyltransferase-catalyzed conversion to S-adenosylmethionine. Of the two genes that encode methionine adenosyltransferase(MAT1Aand MAT2A), MAT1A is mainly expressed in adult liver whereas MAT2A is expressed in all extrahepatic tissues. Mice lacking MAT1A have reduced hepatic S-adenosylmethionine content and hyperplasia and spontaneously develop nonalcoholic steatohepatitis. In this study, we examined whether chronic hepatic S-adenosylmethionine deficiency generates oxidative stress and predisposes to injury and malignant transformation. Differential gene expression in MAT1A knockout mice was analyzed following the criteria of the Gene Ontology Consortium. Susceptibility of MAT1A knockout mice to CCl4-induced hepatotoxicity and malignant transformation was determined in 3- and 18-month-old mice, respectively. Analysis of gene expression profiles revealed an abnormal expression of genes involved in the metabolism of lipids and carbohydrates in MAT1A knockout mice, a situation that is reminiscent of that found in diabetes, obesity, and other conditions associated with nonalcoholic steatohepatitis. This aberrant expression of metabolic genes in the knockout mice was associated with hyperglycemia, increased hepatic CYP2E1 and UCP2 expression and triglyceride levels, and reduced hepatic glutathione content. The knockout animals have increased lipid peroxidation and enhanced sensitivity to CCl4-induced liver damage, which was largely due to increased CYP2E1 expression because diallyl sulfide, an inhibitor of CYP2E1, prevented CCl4-induced liver injury. Hepatocellular carcinoma developed in more than half of the knockout mice by 18 months of age. Taken together, our findings define a critical role for S-adenosylmethionine in maintaining normal hepatic function and tumorigenesis of the liver.