Howard C. Masuoka

Nonalcoholic fatty liver disease: an emerging threat to obese and diabetic individuals.

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in the Western world and its incidence is increasing rapidly. NAFLD is a spectrum ranging from simple steatosis, which is relatively benign hepatically, to nonalcoholic steatohepatitis (NASH), which can progress to cirrhosis. Obesity, insulin resistance, type 2 diabetes mellitus, and dyslipidemia are the most important risk factors for NAFLD. Due to heavy enrichment with metabolic risk factors, individuals with NAFLD are at significantly higher risk for cardiovascular disease. Individuals with NAFLD have higher incidence of type 2 diabetes. The diagnosis of NAFLD requires imaging evidence of hepatic steatosis in the absence of competing etiologies including significant alcohol consumption. Liver biopsy remains the gold standard for diagnosing NASH and for determining prognosis. Weight loss remains a cornerstone of treatment. Weight loss of ∼5% is believed to improve steatosis, whereas ∼10% weight loss is necessary to improve steatohepatitis. A number of pharmacologic therapies have been investigated to treat NASH, and agents such as vitamin E and thiazolidinediones have shown promise in select patient subgroups.

CHOP Links Endoplasmic Reticulum Stress to NF-κB Activation in the Pathogenesis of Nonalcoholic Steatohepatitis

During metabolic stress, the UPR transcription factor CHOP activates NF-κB through a pathway involving IRAK2 expression, resulting in hepatocyte secretion of cytokines IL-8 and TNFα, which trigger inflammation and hepatocellular death.

Relationship Between Changes in Serum Levels of Keratin 18 and Changes in Liver Histology in Children and Adults With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS Cross-sectional studies have associated serum levels of the keratin 18 (K18) fragment with histologic features of liver in individuals with nonalcoholic fatty liver disease (NAFLD). We investigated the relationship between changes in serum levels of K18 and changes in liver histology in adults and children with NAFLD. METHODS We measured levels of K18 in stored serum samples collected at baseline and various time points from 231 adults with nonalcoholic steatohepatitis and 152 children with NAFLD who participated in 2 separate prospective randomized clinical trials. Liver biopsy specimens collected at baseline and week 96 were reviewed centrally. RESULTS There were greater decreases in serum levels of K18 in adults with histologic improvement at week 96 than in those without histologic improvement at week 16 (decrease, 193 ± 293 vs 139 ± 467 U/L; P < .001), week 48 (decrease, 232 ± 360 vs 113 ± 425 U/L; P < .001), or week 96 (decrease, 269 ± 368 vs 97 ± 400 U/L; P < .001). There were greater decreases in serum levels of K18 in children with histologic improvements than in those without histologic improvements at week 48 (decrease, 197 ± 467 vs 47 ± 350 U/L; P = .005) and week 96 (decrease, 206 ± 432 vs 2 ± 474 U/L; P < .001). However, reductions in serum levels of K18 were not better than reductions in levels of alanine aminotransferase in identifying adults with histologic improvement (area under the receiver operator characteristic [AUROC], 0.71; 95% confidence interval [CI], 0.63-0.80; vs AUROC, 0.68; 95% CI, 0.61-0.79; P = .34) or children (AUROC, 0.72; 95% CI, 0.63-0.81; vs AUROC, 0.79; 95% CI, 0.70-0.87; P = .42). CONCLUSIONS Decreases in serum levels of K18 are associated strongly with improved liver histologies in adults or children with NAFLD. However, reductions in K18 do not perform better than those in alanine aminotransferase level in identifying histologic changes in NAFLD.

Transplantation for Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a primary hepatic neoplasm that arises from malignant transformation of the biliary epithelium. Chronic biliary tree inflammation as occurs in primary sclerosing cholangitis (PSC) is a risk factor for the development of CCA. Surgical resection and liver transplantation following neoadjuvant therapy in patients with early extrahepatic CCA are the only potentially curative modalities. Biliary stenting, chemotherapy, radiation therapy, and photodynamic therapy are palliative treatment options for patients who are not surgical candidates. Liver transplantation following neoadjuvant therapy is an effective therapy for patients with hilar cholangiocarcinoma that is unresectable or arising in the setting of PSC.

Severe Drug-Induced Skin and Liver Injury from Rivaroxaban

Rivaroxaban, a direct factor Xa (FXa) inhibitor, is a new oral anticoagulant approved for use in the USA in 2011 for the prevention of deep vein thrombosis in patients undergoing knee and hip replacement surgery. Direct FXa inhibitors generated

Liver Injury and Fibrosis Induced by Dietary Challenge in the Ossabaw Miniature Swine

2.1 billion in 2013, with rivaroxaban accounting for 93.6 % of sales due to label expansion to cover for additional indications [1, 2]. Concern for druginduced liver injury (DILI) from new oral anticoagulants has lingered ever since the termination of the ximelagatran development program [3]. Recent recognition of several spontaneous reports in the pharmacovigilance systems has unfortunately rekindled this concern [4]. A careful analysis of an individual case of suspected DILI from rivaroxaban is therefore very important as the causality assessment in these spontaneous reports is not very robust due to lack of complete information.

Function of inhibitor of Bruton's tyrosine kinase isoform α (IBTKα) in nonalcoholic steatohepatitis links autophagy and the unfolded protein response

Background Ossabaw miniature swine when fed a diet high in fructose, saturated fat and cholesterol (NASH diet) develop metabolic syndrome and nonalcoholic steatohepatitis (NASH) characterized by liver injury and fibrosis. This study was conducted to further characterize the development of NASH in this large animal model. Methods Ossabaw swine were fed standard chow (control group; n = 6) or NASH diet (n = 6) for 24 weeks. Blood and liver tissue were collected and liver histology were characterized at 0, 8, 16 and 24 weeks of dietary intervention. Hepatic apoptosis and lipid levels were assessed at week 24. Results The NASH diet group developed metabolic syndrome and progressive histologic features of NASH including: (a) hepatocyte ballooning at 8 weeks which progressed to extensive ballooning (>90% hepatocytes), (b) hepatic fibrosis at week 16, which progressed to moderate fibrosis, and (c) Kupffer cell accumulation with vacuolization at 8 weeks which progressed through week 24. The NASH diet group showed increased hepatocyte apoptosis that correlated with hepatic total and free cholesterol and free fatty acids, but not esterified cholesterol or triglycerides. Conclusions This report further characterizes the progression of diet-induced NASH in the Ossabaw swine model. In Ossabaw swine fed the NASH diet: (a) hepatocyte injury and fibrosis can occur without macrovesicular steatosis or excess triglyceride accumulation; (b) hepatocyte ballooning generally precedes the development of fibrosis; (c) there is increased hepatocyte apoptosis, and it is correlated more significantly with hepatic free cholesterol than hepatic free fatty acids and had no correlation with hepatic triglycerides.

518 Changes in Serum Cytokeratin 18 Levels Significantly Predict Changes in Liver Histology in Adults With Nonalcoholic Steatohepatitis: Results From the Pivens Trial

Nonalcoholic fatty liver disease (steatosis) is the most prevalent liver disease in the Western world. One of the advanced pathologies is nonalcoholic steatohepatitis (NASH), which is associated with induction of the unfolded protein response (UPR) and disruption of autophagic flux. However, the mechanisms by which these processes contribute to the pathogenesis of human diseases are unclear. Herein, we identify the α isoform of the inhibitor of Brutons tyrosine kinase (IBTKα) as a member of the UPR, whose expression is preferentially translated during endoplasmic reticulum (ER) stress. We found that IBTKα is located in the ER and associates with proteins LC3b, SEC16A, and SEC31A and plays a previously unrecognized role in phagophore initiation from ER exit sites. Depletion of IBTKα helps prevent accumulation of autophagosome intermediates stemming from exposure to saturated free fatty acids and rescues hepatocytes from death. Of note, induction of IBTKα and the UPR, along with inhibition of autophagic flux, was associated with progression from steatosis to NASH in liver biopsies. These results indicate a function for IBTKα in NASH that links autophagy with activation of the UPR.

Serum high mobility group box 1 protein levels are not associated with either histological severity or treatment response in children and adults with nonalcoholic fatty liver disease

Background: Previous cross-sectional studies have shown that serum levels of cytokeratin fragments (CK18) are associated with the presence of steatohepatitis in individuals with nonalcoholic fatty liver disease (NAFLD). However, it is unknown if serial serum CK18 levels can predict longitudinal changes in liver histology in NAFLD. Aim: To determine the degree to which changes in serum CK18 associate with changes in liver histology over a 96-week period in adult patients with nonalcoholic steatohepatitis (NASH). Methods: Serum CK18 levels were measured at baseline and 16, 48, and 96 weeks in 231 of the 247 adults with NASH who participated in the PIVENS trial which investigated the efficacy of pioglitazone vs. vitamin E vs. placebo in non-diabetic individuals with histologically confirmed NASH over a 96-week period. Liver biopsies at baseline and after 96 weeks of treatment were centrally evaluated by the NASH CRN Pathology Committee. Multiple logistic (for categorical outcomes) and linear (for continuous outcome variables) regression models were used to determine the association between changes in histological features, ALT, and % collagen assessed by Sirius red staining, and change in CK18 levels, controlling for baseline CK18 levels and treatment group. Results: At baseline, CK18 levels among the 3 treatment groups were similar (placebo: 440± 350 U/L, vit E: 510± 350 U/L, and pioglitazone: 490± 410 U/L). Compared to placebo, serum CK18 levels among individuals treated with vit E were reduced at week 16 (mean change from baseline -160± 300 vs. -50 ±380 U/L, p= 0.02), week 48 (-220± 390 vs. -10± 370 U/L, p=0.009), and week 96 (-200± 400 vs. 30± 400 U/L, p=0.009). Similarly, compared to placebo, serum CK18 levels among individuals treated with pioglitazone were reduced at week 16 (mean change from baseline -240 ± 390 vs. -50± 380 U/L, p,=0.001), week 48 (-180± 370 vs. -10± 370 U/L, p=0.001, and week 96 (-260 ±400 vs. 30 ± 400 U/L, p=0.001). Strong correlations were seen with change in CK18 levels and the primary histologic endpoint, resolution of NASH, and individual histologic features of NASH (Table 1). In addition, change in CK18 levels strongly correlated with change in ALT levels (b=0.06, 95% CI: 0.04, 0.08; P,0.001).Percent collagen measurements were not related to change in CK18 (b=-0.17 %/100*U/L , 95% CI:-0.70, 0.37; P= 0.54). Summary: (1) Compared to placebo, treatment with vit E or pioglitazone had significant reduction in serum CK18 levels. (2) Changes in serum CK18 correlated with histologic improvement in non-diabetic adults with NASH treated with vitamin E or pioglitazone. Conclusion: Serum CK18 is a potential useful surrogate marker for detection of improvement in clinical trials.

Multifocal Gastric Ulcers Caused by Diffuse Large B Cell Lymphoma in a Patient With Significant Weight Loss

Aim Serum high mobility group box 1 protein (HMGB1) is a proinflammatory molecule that could potentially serve as a biomarker for non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) due to its correlation with degree of liver fibrosis. The aim of the current study was to examine the cross-sectional and longitudinal relationships between serum HMGB1 levels and liver histology in adults and children with NAFLD participating in two large randomized controlled trials. Methods Serum HMGB1 levels were measured at various time points in adults and children with NAFLD, who participated in PIVENS and TONIC clinical trials respectively. PIVENS trial compared vitamin E or pioglitazone to placebo in adults whereas TONIC trial compared vitamin E or metformin to placebo in children. Participants had liver biopsies at baseline and the end of treatment (96 weeks), and liver histology was reviewed by a central committee of study pathologists. Results In the cross-sectional analyses (n = 205 for PIVENS and 109 for TONIC), there was no significant relationship between serum HMGB1 levels and histological features such as steatosis, ballooning, inflammation, fibrosis, or presence of steatohepatitis in either adults or children. Serum HMGB1 levels did not change significantly during treatment either with placebo, vitamin E therapy (P = 0.81) or pioglitazone (P = 0.09) in the PIVENS trial. Similarly, serum HMGB1 levels did not change significantly during treatment either with placebo, metformin (P = 0.15) or vitamin E (P = 0.23) in the TONIC trial. In the longitudinal analyses (n = 105 for PIVENS and 109 for TONIC), changes in serum HMGB1 levels did not correlate with histologic improvement or resolution of NASH in either adults or children. There was no relationship between serum HMGB1 and ALT levels in either adults or children with NAFLD. Conclusion Serum HMGB1 levels were not associated with histological severity or treatment response in either children or adults with NAFLD.