Immune responses are important in dictating nonalcoholic steatohepatitis (NASH) outcome. We previously reported that upregulation of hedgehog (Hh) and osteopontin (OPN) occurs in NASH, that Hh-regulated accumulation of natural killer T (NKT) cells promotes hepatic stellate cell (HSC) activation, and that cirrhotic livers harbor large numbers of NKT cells. Here, we evaluated the hypothesis that activated NKT cells drive fibrogenesis during NASH by assessing if NKT depletion protects against NASH-fibrosis; identifying the NKT associated fibrogenic factors; and correlating plasma levels of the NKT cell-associated factor OPN with fibrosis severity in mice and humans. When fed methionine choline deficient (MCD) diets for 8 weeks, WT mice exhibited Hh pathway activation, enhanced OPN expression, and NASH-fibrosis. Jα18−/− and CD1d−/− mice which lack NKT cells had significantly attenuated Hh and OPN expression and dramatically less fibrosis. Liver mononuclear cells (LMNC) from MCD diet-fed WT mice contained activated NKT cells, generated Hh and OPN, and stimulated hepatic stellate cells (HSC) to become myofibroblasts (MF); neutralizing these factors abrogated the fibrogenic actions of WT LMNC. LMNC from NKT cell deficient mice were deficient in fibrogenic factors, failing to activate collagen gene expression in HSC. Human NASH livers with advanced fibrosis contained more OPN and Hh protein than those with early fibrosis. Plasma levels of OPN mirrored hepatic OPN expression, and correlated with fibrosis severity. In conclusion, hepatic NKT cells drive production of OPN and Hh ligands that promote fibrogenesis during NASH. Associated increases in plasma levels of OPN may provide a biomarker of NASH-fibrosis.

ObjectiveChronic fibrosing liver injury is a major risk factor for hepatocarcinogenesis in humans. Mice with targeted deletion of Mdr2 (the murine ortholog of MDR3) develop chronic fibrosing liver injury. Hepatocellular carcinoma (HCC) emerges spontaneously in such mice by 50–60 weeks of age, providing a model of fibrosis-associated hepatocarcinogenesis. We used Mdr2−/− mice to investigate the hypothesis that activation of the hedgehog (Hh) signaling pathway promotes development of both liver fibrosis and HCC.MethodsHepatic injury and fibrosis, Hh pathway activation, and liver progenitor populations were compared in Mdr2−/− mice and age-matched wild type controls. A dose finding experiment with the Hh signaling antagonist GDC-0449 was performed to optimize Hh pathway inhibition. Mice were then treated with GDC-0449 or vehicle for 9 days, and effects on liver fibrosis and tumor burden were assessed by immunohistochemistry, qRT-PCR, Western blot, and magnetic resonance imaging.ResultsUnlike controls, Mdr2−/− mice consistently expressed Hh ligands and progressively accumulated Hh-responsive liver myofibroblasts and progenitors with age. Treatment of aged Mdr2-deficient mice with GDC-0449 significantly inhibited hepatic Hh activity, decreased liver myofibroblasts and progenitors, reduced liver fibrosis, promoted regression of intra-hepatic HCCs, and decreased the number of metastatic HCC without increasing mortality.ConclusionsHh pathway activation promotes liver fibrosis and hepatocarcinogenesis, and inhibiting Hh signaling safely reverses both processes even when fibrosis and HCC are advanced.

Hepatopulmonary syndrome (HPS) results when chronic liver disease or portal hypertension causes intrapulmonary microvascular dilatation with hypoxemia. In experimental HPS, tumor necrosis factor alpha (TNF-␣) overproduction contributes to vasodilatation, which is improved by pentoxifylline, a TNF-␣ inhibitor. The effectiveness of pentoxifylline in humans is unknown. The aim of this open-label, single-arm clinical trial was to assess the efficacy and tolerability of pentoxifylline in patients with cirrhosis and advanced HPS undergoing liver transplantation evaluation. Nine adults with cirrhosis and moderate to severe HPS were enrolled. All patients had an initial 2-week titration to a target dose of pentoxifylline of 400 mg by mouth every 8 hours, which was continued for 6 weeks. Baseline and follow-up arterial blood gases and TNF-␣ levels were evaluated. Adverse effects and tolerability were assessed. The 9 patients had a mean age of 55 Ϯ 10 years, and 67% were female. The most common causes of cirrhosis were hepatitis C virus and alcohol (55%). The mean Model for End-Stage Liver Disease score was 11 (range, 6-19), and patients had advanced hypoxemia [mean partial pressure of arterial oxygen (PaO 2 ) ϭ 54 Ϯ 12 mm Hg, mean alveolar-arterial oxygen gradient (A-a PaO 2 ) ϭ 57 Ϯ 15 mm Hg]. Of the 9 patients enrolled, follow-up blood gases were done in 7. There was no significant change in PaO 2 (P ϭ 0.3) or A-a PaO 2 (P ϭ 0.3) with treatment. Pentoxifylline was poorly tolerated. Nausea (100%) and vomiting (56%) were the predominant side effects, and only a single patient was able to complete full-dose therapy. Treatment with pentoxifylline did not improve arterial oxygenation in advanced HPS, and tolerance was limited by gastrointestinal toxicity. Liver Transpl 14: [1199][1200][1201][1202][1203] 2008 Hepatopulmonary syndrome (HPS) results from intrapulmonary microvascular dilatation that impairs arterial oxygenation in the setting of cirrhosis or portal hypertension. 1 As many as 10%-20% of patients with cirrhosis being evaluated for orthotopic liver transplantation (OLT) have advanced HPS, 2 and mortality is greater in those with HPS than in those without HPS. 3 Currently, OLT is the only effective treatment, although postoperative mortality in HPS is increased with respect to patients with cirrhosis without HPS, with a 1-year survival of 68% to 80%. 4 Therefore, effective medical therapy for advanced HPS could improve both preoperative and postoperative mortality.Recent work in experimental models of HPS has revealed that both nitric oxide synthase-derived nitric oxide and heme oxygenase-derived carbon monoxide cause intrapulmonary vasodilatation. These alterations appear to be driven in part by tumor necrosis factor alpha (TNF-␣) modulation of pulmonary blood flow and intravascular monocyte accumulation. 5-7 PentoxifyllineAbbreviations: A-a PaO 2 , alveolar-arterial oxygen gradient; ALT, alanine aminotransferase; AST, aspartate aminotransferase; HCV, hepatitis C virus; HPS, hepatopulmonary syndrome; INR, internat...

Sleep alters respiratory mechanics and gas exchange, which can adversely affect arterial oxygenation. Whether sleep affects oxygenation in hepatopulmonary syndrome is unknown. The aim of this study was to assess oxygen desaturation during sleep in hepatopulmonary syndrome. Twenty adults with cirrhosis including 10 controls and 10 patients with hepatopulmonary syndrome underwent home pulse-oximetry during sleep. Subjects at high risk for obstructive sleep apnea were excluded through the Berlin questionnaire. Subjects who spent more than 10% of total sleep time with arterial oxygen saturation < 90% were classified as sleep-time oxygen desaturators. Sleep-time desaturation was correlated with clinical variables. The results showed that 7 of 10 hepatopulmonary syndrome subjects and none of the 10 controls had sleep-time oxygen desaturation. The median percentage of total sleep time with arterial oxygen saturation < 90% was significantly higher in hepatopulmonary syndrome subjects than in controls (medians 25% versus 0%, P ‫؍‬ 0.005). Hepatopulmonary syndrome subjects had significantly lower wake-time arterial oxygen saturation level (median, 97% versus 95%; P ‫؍‬ 0.003) and mean sleep-time arterial oxygen saturation level (median, 96% versus 91%; P ‫؍‬ 0.0008) than did the controls. Sleep-time desaturation directly correlated with alveolar-arterial oxygen gradient (P ‫؍‬ 0.0007) and inversely correlated with wake-time arterial oxygen tension (P ‫؍‬ 0.0007) and oxygen saturation (P < 0.0001). Conclusion: Oxygen desaturation occurred during sleep in 70% of hepatopulmonary syndrome subjects, the degree of which correlated with the severity of hepatopulmonary syndrome. Marked hypoxemia during sleep may occur in hepatopulmonary syndrome patients who, according to wake-time oxygen values, have only mild to moderate hypoxemia.

This preliminary study showed for the first time that training for POEM can be performed in a step-by-step fashion, learning mucosal incision, submucosal dissection, myotomy, and mucosal incision closure from an expert interventional endoscopist without increasing adverse events. The checklist for each step could be used as an important guide in training POEM. The outcomes of POEM in this study were similar to those reported by others without trainees. Further multiple center studies are needed to verify this training process and to establish a formal training protocol.