Hepatology : official journal of the American Association for the Study of Liver Diseases
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Sofosbuvir (SOF) in combination with ribavirin (RBV) for 12 or 24 weeks is the current standard of care for patients infected with hepatitis C virus (HCV) genotypes 2 and 3, respectively. However, in clinical trials treatment-experienced patients, particularly those with cirrhosis, had suboptimal sustained virological response (SVR) rates. We assessed the efficacy and safety of sofosbuvir plus peginterferon and ribavirin (SOF+Peg-IFN+RBV) administered for 12 weeks to treatment-experienced patients with HCV genotypes 2 and 3, with and without cirrhosis. We enrolled 47 patients in this open-label, nonrandomized, uncontrolled phase 2 study. The primary endpoint was the proportion of patients with SVR at 12 weeks after cessation of study treatment (SVR12). The overall rate of SVR12 was 89% (95% confidence interval [CI]: 77-97). Rates of SVR12 were higher in patients with genotype 2 than in those with genotype 3, 96% (95% CI: 78-100) and 83% (95% CI: 62-95), respectively. Rates of SVR12 were similar in patients with and without cirrhosis: for genotype 2, 93% of patients with cirrhosis and 100% of patients without cirrhosis achieved SVR12, and for genotype 3, the SVR12 rate was 83% in patients both with and without cirrhosis. One patient discontinued study treatment because of an adverse event and four patients experienced serious adverse events. The most common adverse events were influenza-like illness, fatigue, anemia, and neutropenia. ⋯ In treatment-experienced patients with HCV genotypes 2 and 3, 12-week administration of SOF+Peg-IFN+RBV provided high SVR rates, irrespective of cirrhosis status. No safety concerns were identified.
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Plasma aminotransferases (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) are usually increased in patients with nonalcoholic fatty liver disease (NAFLD). However, the factors behind their elevation remain unclear. The aim of this study was to assess the role of insulin resistance (IR) and liver triglyceride content in relation to histology in patients with NAFLD/nonalcoholic steatohepatitis (NASH) with normal or elevated ALT levels. To this end, we enrolled 440 patients, divided into three groups: no NAFLD (n = 60); NAFLD with normal ALT (n = 165); and NAFLD with elevated ALT (n = 215). We measured: (1) liver fat by proton magnetic resonance spectroscopy ((1)H-MRS); (2) severity of liver disease by biopsy (n = 293); and (3) insulin sensitivity in liver, muscle, and adipose tissue by a euglycemic hyperinsulinemic clamp with 3-(3)H-glucose. Patients with NAFLD and elevated ALT, even when well matched for body mass index to those with normal ALT, had worse adipose tissue insulin resistance (ATIR; P < 0.0001), higher liver triglyceride content (P < 0.0001), and lower plasma adiponectin (P < 0.05), but no differences in hepatic insulin resistance. Similar results were found when only patients with NASH were compared: both ATIR (P < 0.0001) and liver triglyceride content by (1)H-MRS (P < 0.0001) were worse in NASH with elevated ALT. Consistent with the (1)H-MRS data, steatosis on liver biopsy was also significantly increased in patients with NASH and elevated ALT levels (P < 0.0001). However, and most important, there were no differences in inflammation (P = 0.62), ballooning (P = 0.13), or fibrosis (P = 0.12). ⋯ In patients with NAFLD or NASH, ATIR (but not HIR) and liver triglyceride content are major factors in the elevation of plasma aminotransferase levels. Patients with normal versus elevated ALT had similar severity of NASH, suggesting that plasma aminotransferase levels are misleading parameters for guiding clinical management.
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Targeting mitochondria with methylene blue protects mice against acetaminophen-induced liver injury.
Acetaminophen (APAP) overdose is a frequent cause of drug-induced liver injury and the most frequent cause of acute liver failure in the Western world. Previous studies with mouse models have revealed that impairment of mitochondrial respiration is an early event in the pathogenesis, but the exact mechanisms have remained unclear, and therapeutic approaches to specifically target mitochondria have been insufficiently explored. Here, we found that the reactive oxidative metabolite of APAP, N-acetyl-p-benzoquinoneimine (NAPQI), caused the selective inhibition of mitochondrial complex II activity by >90% in both mouse hepatic mitochondria and yeast-derived complexes reconstituted into nanoscale model membranes, as well as the decrease of succinate-driven adenosine triphosphate (ATP) biosynthesis rates. Based on these findings, we hypothesized that methylene blue (MB), a mitochondria-permeant redox-active compound that can act as an alternative electron carrier, protects against APAP-induced hepatocyte injury. We found that MB (<3 µM) readily accepted electrons from NAPQI-altered, succinate-energized complex II and transferred them to cytochrome c, restoring ATP biosynthesis rates. In cultured mouse hepatocytes, MB prevented the mitochondrial permeability transition and loss of intracellular ATP without interfering with APAP bioactivation. In male C57BL/6J mice treated with APAP (450 mg/kg, intraperitoneally [IP]), MB (10 mg/kg, IP, administered 90 minutes post-APAP) protected against hepatotoxicity, whereas mice treated with APAP alone developed massive centrilobular necrosis and increased serum alanine aminotransferase activity. APAP treatment inhibited complex II activity ex vivo, but did not alter the protein expression levels of subunits SdhA or SdhC after 4 hours. ⋯ MB can effectively protect mice against APAP-induced liver injury by bypassing the NAPQI-altered mitochondrial complex II, thus alleviating the cellular energy crisis. Because MB is a clinically used drug, its potential application after APAP overdose in patients should be further explored.