Nathan M. Bass

Pioglitazone, Vitamin E, or Placebo for Nonalcoholic Steatohepatitis

BACKGROUND Nonalcoholic steatohepatitis is a common liver disease that can progress to cirrhosis. Currently, there is no established treatment for this disease. METHODS We randomly assigned 247 adults with nonalcoholic steatohepatitis and without diabetes to receive pioglitazone at a dose of 30 mg daily (80 subjects), vitamin E at a dose of 800 IU daily (84 subjects), or placebo (83 subjects), for 96 weeks. The primary outcome was an improvement in histologic features of nonalcoholic steatohepatitis, as assessed with the use of a composite of standardized scores for steatosis, lobular inflammation, hepatocellular ballooning, and fibrosis. Given the two planned primary comparisons, P values of less than 0.025 were considered to indicate statistical significance. RESULTS Vitamin E therapy, as compared with placebo, was associated with a significantly higher rate of improvement in nonalcoholic steatohepatitis (43% vs. 19%, P=0.001), but the difference in the rate of improvement with pioglitazone as compared with placebo was not significant (34% and 19%, respectively; P=0.04). Serum alanine and aspartate aminotransferase levels were reduced with vitamin E and with pioglitazone, as compared with placebo (P<0.001 for both comparisons), and both agents were associated with reductions in hepatic steatosis (P=0.005 for vitamin E and P<0.001 for pioglitazone) and lobular inflammation (P=0.02 for vitamin E and P=0.004 for pioglitazone) but not with improvement in fibrosis scores (P=0.24 for vitamin E and P=0.12 for pioglitazone). Subjects who received pioglitazone gained more weight than did those who received vitamin E or placebo; the rates of other side effects were similar among the three groups. CONCLUSIONS Vitamin E was superior to placebo for the treatment of nonalcoholic steatohepatitis in adults without diabetes. There was no benefit of pioglitazone over placebo for the primary outcome; however, significant benefits of pioglitazone were observed for some of the secondary outcomes. (ClinicalTrials.gov number, NCT00063622.)

Rifaximin Treatment in Hepatic Encephalopathy

BACKGROUND Hepatic encephalopathy is a chronically debilitating complication of hepatic cirrhosis. The efficacy of rifaximin, a minimally absorbed antibiotic, is well documented in the treatment of acute hepatic encephalopathy, but its efficacy for prevention of the disease has not been established. METHODS In this randomized, double-blind, placebo-controlled trial, we randomly assigned 299 patients who were in remission from recurrent hepatic encephalopathy resulting from chronic liver disease to receive either rifaximin, at a dose of 550 mg twice daily (140 patients), or placebo (159 patients) for 6 months. The primary efficacy end point was the time to the first breakthrough episode of hepatic encephalopathy. The key secondary end point was the time to the first hospitalization involving hepatic encephalopathy. RESULTS Rifaximin significantly reduced the risk of an episode of hepatic encephalopathy, as compared with placebo, over a 6-month period (hazard ratio with rifaximin, 0.42; 95% confidence interval [CI], 0.28 to 0.64; P<0.001). A breakthrough episode of hepatic encephalopathy occurred in 22.1% of patients in the rifaximin group, as compared with 45.9% of patients in the placebo group. A total of 13.6% of the patients in the rifaximin group had a hospitalization involving hepatic encephalopathy, as compared with 22.6% of patients in the placebo group, for a hazard ratio of 0.50 (95% CI, 0.29 to 0.87; P=0.01). More than 90% of patients received concomitant lactulose therapy. The incidence of adverse events reported during the study was similar in the two groups, as was the incidence of serious adverse events. CONCLUSIONS Over a 6-month period, treatment with rifaximin maintained remission from hepatic encephalopathy more effectively than did placebo. Rifaximin treatment also significantly reduced the risk of hospitalization involving hepatic encephalopathy. (ClinicalTrials.gov number, NCT00298038.)

SIRT3 Deficiency and Mitochondrial Protein Hyperacetylation Accelerate the Development of the Metabolic Syndrome

Acetylation is increasingly recognized as an important metabolic regulatory posttranslational protein modification, yet the metabolic consequence of mitochondrial protein hyperacetylation is unknown. We find that high-fat diet (HFD) feeding induces hepatic mitochondrial protein hyperacetylation in mice and downregulation of the major mitochondrial protein deacetylase SIRT3. Mice lacking SIRT3 (SIRT3KO) placed on a HFD show accelerated obesity, insulin resistance, hyperlipidemia, and steatohepatitis compared to wild-type (WT) mice. The lipogenic enzyme stearoyl-CoA desaturase 1 is highly induced in SIRT3KO mice, and its deletion rescues both WT and SIRT3KO mice from HFD-induced hepatic steatosis and insulin resistance. We further identify a single nucleotide polymorphism in the human SIRT3 gene that is suggestive of a genetic association with the metabolic syndrome. This polymorphism encodes a point mutation in the SIRT3 protein, which reduces its overall enzymatic efficiency. Our findings show that loss of SIRT3 and dysregulation of mitochondrial protein acetylation contribute to the metabolic syndrome.

Excellent Outcome Following Down-Staging of Hepatocellular Carcinoma Prior to Liver Transplantation: An Intention-to-Treat Analysis

We previously reported encouraging results of down‐staging of hepatocellular carcinoma (HCC) to meet conventional T2 criteria (one lesion 2–5 cm or two to three lesions <3 cm) for orthotopic liver transplantation (OLT) in 30 patients as a test of concept. In this ongoing prospective study, we analyzed longer‐term outcome data on HCC down‐staging in a larger cohort of 61 patients with tumor stage exceeding T2 criteria who were enrolled between June 2002 and January 2007. Eligibility criteria for down‐staging included: (1) one lesion >5 cm and up to 8 cm; (2) two to three lesions with at least one lesion >3 cm and not exceeding 5 cm, with total tumor diameter up to 8 cm; or (3) four to five lesions with none >3 cm, with total tumor diameter up to 8 cm. A minimum observation period of 3 months after down‐staging was required before OLT. Tumor down‐staging was successful in 43 patients (70.5%). Thirty‐five patients (57.4%) had received OLT, including two who had undergone live‐donor liver transplantation. Treatment failure was observed in 18 patients (29.5%), primarily due to tumor progression. In the explant of 35 patients who underwent OLT, 13 had complete tumor necrosis, 17 met T2 criteria, and five exceeded T2 criteria. The Kaplan‐Meier intention‐to‐treat survival at 1 and 4 years after down‐staging were 87.5% and 69.3%, respectively. The 1‐year and 4‐year posttransplantation survival rates were 96.2% and 92.1%, respectively. No patient had HCC recurrence after a median posttransplantation follow‐up of 25 months. The only factor predicting treatment failure was pretreatment alpha‐fetoprotein >1,000 ng/mL. Conclusion: Successful down‐staging of HCC can be achieved in the majority of carefully selected patients and is associated with excellent posttransplantation outcome. (HEPATOLOGY 2008.)

Liver Transplantation for Hepatocellular Carcinoma: Validation of the UCSF‐Expanded Criteria Based on Preoperative Imaging

We previously suggested that in patients with heptocellular carcinoma (HCC), the conventional Milan criteria (T1/T2) for orthotopic liver transplantation (OLT) could be modestly expanded based on pathology (UCSF criteria). The present study was undertaken to prospectively validate the UCSF criteria based on pretransplant imaging. Over a 5‐year period, the UCSF criteria were used as selection guidelines for OLT in 168 patients, including 38 patients exceeding Milan but meeting UCSF criteria (T3A). The 1‐ and 5‐year recurrence‐free probabilities were 95.9% and 90.9%, and the respective survivals without recurrence were 92.1% and 80.7%. Patients with preoperative T1/T2 HCC had 1‐ and 5‐year recurrence‐free probabilities of 95.7% and 90.1%, respectively, versus 96.9% and 93.6%, respectively, for preoperative T3A stage (p = 0.58). Under‐staging was observed in 20% of T2 and 29% of T3A HCC (p = 0.26). When explant tumor exceeded UCSF criteria (15%), the 1‐ and 5‐year recurrence‐free probabilities were 80.4% and 59.5%, versus 98.6% and 96.7%, respectively, for those within UCSF criteria (p < 0.0001). In conclusion, our results validated the ability of the UCSF criteria to discriminate prognosis after OLT and to serve as selection criteria for OLT, with a similar risk of tumor recurrence and under‐staging when compared to the Milan criteria.

Serum sodium predicts mortality in patients listed for liver transplantation.

With the implementation of the model for end‐stage liver disease (MELD), refractory ascites, a known predictor of mortality in cirrhosis, was removed as a criterion for liver allocation. Because ascites is associated with low serum sodium, we evaluated serum sodium as an independent predictor of mortality in patients with cirrhosis who were listed for liver transplantation and whether the addition of serum sodium to MELD was superior to MELD alone. This is a single‐center retrospective cohort of all adult patients with cirrhosis listed for transplantation from February 27, 2002, to December 26, 2003. Listing laboratories were those nearest the listing date ±2 months. Of the 513 patients meeting inclusion criteria, 341 were still listed, while 172 were removed from the list (105 for transplantation, 56 for death, 11 for other reasons). The median serum sodium and MELD scores were 137 mEq/L (range, 110‐155) and 15 (range, 6‐51), respectively, at listing. Median follow‐up was 201 (range, 1‐662) days. The risk of death with serum sodium < 126 mEq/L at listing or while listed was increased, with hazard ratios of 7.8 (P < .001) and 6.3 (P < .001), respectively, and the association was independent of MELD. The c‐statistics of receiver operating characteristic curves for predicting mortality at 3 months based upon listing MELD with and without listing serum sodium were 0.883 and 0.897, respectively, and at 6 months were 0.871 and 0.905, respectively. In conclusion, serum sodium < 126 mEq/L at listing or while listed for transplantation is a strong independent predictor of mortality. Addition of serum sodium to MELD increases the ability to predict 3‐ and 6‐month mortality in patients with cirrhosis. (HEPATOLOGY 2005;41:32–39.)

Racial and ethnic distribution of nonalcoholic fatty liver in persons with newly diagnosed chronic liver disease

We performed a cross‐sectional study of newly diagnosed cases of nonalcoholic fatty liver disease (NAFLD) identified between December 1998 and December 2000 in the Chronic Liver Disease Surveillance Study. We compared the demographic and clinical features of NAFLD in a racially diverse representative U.S. population (Alameda County, CA). Diagnostic criteria for probable NAFLD were persistent unexplained elevation of serum aminotransferase levels, radiology (ultrasound or computed tomography scan) consistent with fatty liver, and/or two or more of the following: (i) body mass index of 28 kg/m2 or more, (ii) type 2 diabetes, or (iii) hyperlipidemia, in the absence of significant alcohol use. Definite NAFLD cases required histological confirmation. Of the 742 persons with newly diagnosed chronic liver disease, 159 (21.4%) had definite or probable NAFLD. The majority were nonwhite: Hispanics (28%), Asians (18%), African Americans (3%), and other race(s) (6%). African Americans with NAFLD were significantly older than other racial or ethnic groups (P < .001), and in Asians, NAFLD was 3.5 times more common in males than in females (P = .016). Clinical correlates of NAFLD (obesity, hyperlipidemia, diabetes) were similar among racial and ethnic groups, except that body mass index was lower in Asians compared with other groups (P < .001). Compared with the base population (Kaiser Permanente members), Hispanics with NAFLD were overrepresented (28% vs. 10%) and whites were underrepresented (45% vs. 59%). In conclusion, these racial and gender variations may reflect differences in genetic susceptibility to visceral adiposity, including hepatic involvement, and may have implications for the evaluation of persons with the metabolic syndrome. Clinicians need to be aware of the variable presentations of NAFLD in different racial and ethnic groups. (HEPATOLOGY 2005;41:372–379.)

Clinical, laboratory and histological associations in adults with nonalcoholic fatty liver disease

The Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) was formed to conduct multicenter studies on the etiology, contributing factors, natural history, and treatment of nonalcoholic steatohepatitis (NASH). The aim of this study was to determine the associations of readily available demographic, clinical, and laboratory variables with the diagnosis of NASH and its key histological features, and determine the ability of these variables to predict the severity of nonalcoholic fatty liver disease (NAFLD). A total of 1266 adults were enrolled in NASH CRN studies between October 2004 and February 2008, of whom 1101 had available liver histology. The median age was 50 years; 82% were white and 12% Hispanic. The median body mass index was 33 kg/m2; 49% had hypertension and 31% had type 2 diabetes. On liver biopsy, 57% were judged to have definite NASH and 31% bridging fibrosis or cirrhosis. Using data from the 698 patients with liver biopsies within 6 months of clinical data, patients with definite NASH were more likely to be female and have diabetes, higher levels of aspartate and alanine aminotransferases, alkaline phosphatase, gamma glutamyl transpeptidase, and homeostasis model assessment of insulin resistance (HOMA‐IR). Progressive models for predicting histological diagnoses performed modestly for predicting steatohepatitis or ballooning (area under receiver operating characteristic curves [AUROC] ranged from 0.70‐0.79), and better for advanced fibrosis (AUROC 0.73‐0.85). Conclusion: Readily available clinical and laboratory variables can predict advanced fibrosis in adults with NAFLD, but additional information is needed to reliably predict the presence and severity of NASH. Prospective studies of this well‐characterized population and associated tissue bank samples offer a unique opportunity to better understand the cause and natural history of NAFLD and develop more precise means for noninvasive diagnosis. (HEPATOLOGY 2010)

Correlation of paired liver biopsies in morbidly obese patients with suspected nonalcoholic fatty liver disease

In the absence of surrogate markers, the evaluation of suspected nonalcoholic fatty liver disease (NAFLD) is highly dependent on histological examination. The extent of sampling variability affecting the reliability of a single liver biopsy in patients with suspected NAFLD is poorly characterized. This prospective study aimed to correlate precise histological findings in paired biopsies—right and left lobe—in the diagnosis of NAFLD in morbidly obese subjects undergoing bariatric surgery employing both Brunt and Matteoni classifications and the NAFLD Activity Score (NAS). We also aimed to determine whether the composite histopathological findings of the two biopsies would improve diagnostic accuracy. Consecutive subjects had an intraoperative biopsy from both right and left lobes, evaluated and scored in a blinded manner. Intraobserver agreement was also assessed. Kappa coefficients of agreement were calculated. Forty‐one subjects had acceptable biopsies. Agreement for steatosis was excellent and moderate for fibrosis. Concordance was only fair for most features of necroinflammation. Intraobserver agreement was only moderate for lobular inflammation. Excellent agreement was seen for the diagnosis of NASH using Brunt criteria and good agreement when using Matteoni and NAS scoring systems. Composite biopsy data particularly improved identification of hepatocyte ballooning. The diagnostic accuracy also improved substantially when composite features were compared with single‐sided biopsy features, especially for the Matteoni and NAS scoring systems. In conclusion, significant sampling variability occurs in NAFLD, particularly for features of necroinflammation. This should be factored into the design of clinical trials and studies of the natural history of the disease. (HEPATOLOGY 2006;44:874–880.)

The cellular fatty acid binding proteins: aspects of structure, regulation, and function.

Publisher Summary This chapter provides a comprehensive overview of the current state of knowledge of the research with particular emphasis on evolving concepts of fatty acid binding proteins (FABP) structure, regulation, and function. Long-chain fatty acids provide the main energy source of most mammalian tissues and also comprise essential components of the structural lipids of cell membranes. The purification of the specific proteins responsible for the low-molecular-weight fatty-acid binding protein activity in different tissues leads to the characterization of three structurally distinct FABP of similar size, each the product of a separate gene. The three cytosolic FABP are generally named according to their tissues of greatest abundance, and comprise liver FABP, intestinal FABP, and heart muscle FABP. A role for the 40-kDa LPM-FABP as a specific cell membrane carrier in the transport of long chain fatty acids into the cells of the liver and possibly other tissues as well is available. The 14- to 15-kDa cytosolic FABPs may function as intracellular acceptors and carriers of long-chain fatty acids and their coenzyme A (CoA) esters, maintaining the ability of the tissues, particularly liver, intestine, heart, and skeletal muscle to utilize fatty acids over wide and acutely varying ranges of flux.