Current and future therapeutic regimens for nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Allyl isothiocyanate ameliorates lipid accumulation and inflammation in nonalcoholic fatty liver disease via the Sirt1/AMPK and NF-κB signaling pathways

BACKGROUND

Allyl isothiocyanate (AITC), a classic anti-inflammatory and antitumorigenic agent, was recently identified as a potential treatment for obesity and insulin resistance. However, little is known about its direct impact on the liver.

AIM

To investigate the effect and underlying mechanism of AITC in nonalcoholic fatty liver disease (commonly referred to as NAFLD).

METHODS

To establish a mouse and cellular model of NAFLD, C57BL/6 mice were fed a high fat diet (HFD) for 8 wk, and AML-12 cells were treated with 200 μM palmitate acid for 24 h. For AITC treatment, mice were administered AITC (100 mg/kg/d) orally and AML-12 cells were treated with AITC (20 μmol/L).

RESULTS

AITC significantly ameliorated HFD-induced weight gain, hepatic lipid accumulation and inflammation in vivo. Furthermore, serum alanine aminotransferase and aspartate aminotransferase levels were markedly reduced in AITC-treated mice. Mechanistically, AITC significantly downregulated the protein levels of sterol regulatory element­binding protein 1 (SREBP1) and its lipogenesis target genes and upregulated the levels of proteins involved in fatty acid β-oxidation, as well as the upstream mediators Sirtuin 1 (Sirt1) and AMP-activated protein kinase α (AMPKα), in the livers of HFD-fed mice. AITC also attenuated the nuclear factor kappa B (NF-κB) signaling pathway. Consistently, AITC relieved palmitate acid-induced lipid accumulation and inflammation in AML-12 cells in vitro through the Sirt1/AMPK and NF-κB signaling pathways. Importantly, further studies showed that the curative effect of AITC on lipid accumulation was abolished by siRNA-mediated knockdown of either Sirt1 or AMPKα in AML-12 cells.

CONCLUSION

AITC significantly ameliorates hepatic steatosis and inflammation by activating the Sirt1/AMPK pathway and inhibiting the NF-κB pathway. Therefore, AITC is a potential therapeutic agent for NAFLD.

Indole-3-propionic acid inhibits gut dysbiosis and endotoxin leakage to attenuate steatohepatitis in rats

Microbial metabolites have emerged as critical components that mediate the metabolic effects of the gut microbiota. Here, we show that indole-3-propionic acid (IPA), a tryptophan metabolite produced by gut bacteria, is a potent anti-non-alcoholic steatohepatitis (NASH) microbial metabolite. Here, we demonstrate that administration of IPA modulates the microbiota composition in the gut and inhibits microbial dysbiosis in rats fed a high-fat diet. IPA induces the expression of tight junction proteins, such as ZO-1 and Occludin, and maintains intestinal epithelium homeostasis, leading to a reduction in plasma endotoxin levels. Interestingly, IPA inhibits NF-κB signaling and reduces the levels of proinflammatory cytokines, such as TNFα, IL-1β, and IL-6, in response to endotoxin in macrophages to repress hepatic inflammation and liver injury. Moreover, IPA is sufficient to inhibit the expression of fibrogenic and collagen genes and attenuate diet-induced NASH phenotypes. The beneficial effects of IPA on the liver are likely mediated through inhibiting the production of endotoxin in the gut. These findings suggest a protective role of IPA in the control of metabolism and uncover the gut microbiome and liver cross-talk in regulating the intestinal microenvironment and liver pathology via a novel dietary nutrient metabolite. IPA may provide a new therapeutic strategy for treating NASH.

A molecule made by beneficial microbes in the gut helps protect against a severe form of fatty liver disease by preventing bacterial toxins from leaking out of the intestines into the bloodstream. A research team in China led by Yu Li from the Shanghai Institute of Nutrition and Health (CAS) and Jian-Gao Fan from Xinhua Hospital (SJTU) showed in a rat model of non-alcoholic steatohepatitis that indole-3-propionic acid (IPA), a metabolite produced by gut bacteria, helps maintain the integrity of the intestinal inner lining. The more robust intestinal barrier ensures that bacterial toxins do not enter the bloodstream and eventually reach the liver, where they can trigger injury-inducing inflammation. The findings reveal an interaction between the gut microbiome and the liver, and suggest a role for IPA in the treatment of fatty liver disease.

The Role of Innate Immune Cells in Nonalcoholic Steatohepatitis

Inflammation and metabolic dysfunction are hallmarks of nonalcoholic steatohepatitis (NASH), which is one of the fastest-growing liver diseases worldwide. Emerging evidence indicates that innate immune mechanisms are pivotal drivers of inflammation and other pathological manifestations observed in NASH, such as hepatosteatosis, insulin resistance (IR), and fibrosis. This robust innate immune reaction is intrinsic to the liver, which is an important immunological organ that contains a coordinated network of innate immune cells, including Kupffer cells (KCs), dendritic cells (DCs), and lymphocytes. Hepatocytes and liver sinusoidal endothelial cells (LSECs) are not formally innate immune cells, but they take on immune cell function when stressed. These cells can sense excess metabolites and bacterial products and translate those signals into immune responses and pathological hepatic changes during the development of NASH. In this review, we take a historical perspective in describing decades of research that aimed to identify the key molecular and cellular players in the innate immune system in the setting of NASH. Furthermore, we summarize the innate immune cells that are involved in the progression of NASH and illustrate how they sense disturbances in circulating metabolic factors by innate immune receptors and subsequently initiate the intercellular signaling cascades that lead to persistent inflammation and progression of hepatic complications.

Sequential drug delivery for liver diseases

The liver performs critical physiological functions such as metabolism/detoxification and blood homeostasis/biliary excretion. A high degree of blood access means that a drug's resident time in any cell is relatively short. This short drug exposure to cells requires local sequential delivery of multiple drugs for optimal efficacy, potency, and safety. The high metabolism and excretion of drugs also impose both technical challenges and opportunities to sequential drug delivery. This review provides an overview of the sequential events in liver regeneration and the related liver diseases. Using selected examples of liver cancer, hepatitis B viral infection, fatty liver diseases, and drug-induced liver injury, we highlight efforts made for the sequential delivery of small and macromolecular drugs through different biomaterials, cells, and microdevice-based delivery platforms that allow fast delivery kinetics and rapid drug switching. As this is a nascent area of development, we extrapolate and compare the results with other sequential drug delivery studies to suggest possible application in liver diseases, wherever appropriate.

Validation of Chronic Liver Disease Questionnaire for Nonalcoholic Steatohepatitis in Patients With Biopsy-Proven Nonalcoholic Steatohepatitis

BACKGROUND & AIMS

The chronic liver disease questionnaire for nonalcoholic steatohepatitis (CLDQ-NASH) was developed in a systematic manner for assessment of patient-reported outcomes. This instrument collects data on 36 items grouped into 6 domains: abdominal symptoms, activity/energy, emotional health, fatigue, systemic symptoms, and worry. We aimed to validate the CLDQ-NASH in a large group of patients with NASH.

METHODS

We collected data from patients with biopsy-proven NASH enrolled in 2 international phase 3 trials of selonsertib (NCT03053050 and NCT03053063). Our final analysis comprised 1667 patients who completed the CLDQ-NASH (age, 58 ± 9 y; 40% male; 52% with cirrhosis; and 69% with type 2 diabetes). The CLDQ-NASH was administered before treatment initiation. A standard patient-reported outcome instrument validation pipeline with internal consistency and validity assessment was applied.

RESULTS

The domains of CLDQ-NASH showed good to excellent internal consistency: the Cronbach's α values were 0.80 to 0.94 and item-to-own-domain correlations were greater than 0.50 for 33 of 36 items. All items correlated to the greatest extent with their own domains (discriminant validity). Known-group validity tests indicated that the instrument consistently discriminated between patients with NASH based on the presence of cirrhosis (vs bridging fibrosis; all but 1 P value < .02), obesity (all but 1 P value < .001), psychiatric comorbidities (all P values < .0001), fatigue (all P values < .001), and type 2 diabetes (all but 1 P value < .01). Of the CLDQ-NASH domains, the highest correlated domains with the Short Form-36 were as follows: physical functioning for activity (rho = 0.70), mental health for emotional (rho = 0.72), vitality for fatigue (rho = 0.75), and body pain for systemic (rho = 0.72) (all P values < .0001). In contrast, the domains of abdominal and worry, which are disease-specific, did not correlate with the domains in the Short Form-36 (all rho ≤ 0.50).

CONCLUSIONS

We validated the CLDQ-NASH by an analysis of data from 1667 patients with biopsy-proven NASH enrolled in phase 3 trials, observing excellent psychometric characteristics of the instrument.

Diabetes Association with Liver Diseases: An Overview for Clinicians

BACKGROUND

There is a strong association between liver diseases and diabetes (DM) which is higher than expected by a correlation between two very common diseases. Liver diseases may occur as a result of diabetes, and the reverse is true as well.

AIM

To review the etiology of this association between liver diseases and diabetes and how to diagnose it.

METHODS

Studies that identified this association between liver diseases and diabetes and how to diagnose it was reviewed.

RESULTS

This association can be divided into the following categories: liver disease related to diabetes (Diabetic hepatopathy), hepatogenous diabetes (HD), and liver diseases that occur in conjunction with Diabetes mellitus. Two hours after glucose loading is the best screening test for HD. HbA1c may neither be suitable for diagnosis nor monitoring of diabetes that links liver disease.

CONCLUSION

NAFLD, hepatogenous diabetes, glycogenic hepatopathy and diabetic hepatosclerosis are the most important association between liver diseases and diabetes. The criteria for the diagnosis of diabetes associating liver disease are the same for primary diabetes. Two hours post glucose load is the best screening test for HD due to the fact that fasting glucose can be normal early in the disease. The tool used for diabetes monitoring depends on stage and severity of liver condition.

Mortality Related to Nonalcoholic Fatty Liver Disease Is Increasing in the United States

Population‐level nonalcoholic fatty liver disease (NAFLD) death rate data are sparse. We described death rates for adults with NAFLD in the United States using mortality data from the National Vital Statistics System multiple‐cause mortality data (2007‐2016). Decedents who had NAFLD were identified by International Classification of Diseases (ICD) codes K75.81, K76.0, K74.0, K74.6, and K76.9. Among NAFLD decedents, cause‐specific deaths (e.g., cardiovascular disease [CVD], cirrhosis, hepatocellular carcinoma [HCC], non‐liver cancer, diabetes mellitus [DM]) were identified by underlying cause of death ICD‐10 codes. Trends were evaluated by average annual percentage change (AAPC) in age‐standardized death rate (ASDR) per 100,000 persons. Among the 25,129,960 decedents aged ≥20 years, 353,234 (1.4%) decedents had NAFLD (212,322 men; 260,765 non‐Hispanic whites, 32,868 non‐Hispanic blacks, 46,530 Hispanics, 5,025 non‐Hispanic American Indian or Alaska Natives [AIANs], 7,023 non‐Hispanic Asian or Pacific Islanders [APIs]), with a mean age at death of 64.47 ± 13.17 years. During the study period, the ASDR for NAFLD increased by 15% (12.94 to 14.90; AAPC, 1.98%; P < 0.001]), while women (AAPC, 2.99% vs. 1.16% men; P = 0.003), non‐Hispanic whites (AAPC, 2.48%), non‐Hispanic AIANs (AAPC, 2.31%), and Hispanics (AAPC, 0.74%) experienced the highest annual increases. Stable trends were noted for non‐Hispanic blacks and non‐Hispanic APIs. Among subgroups, Mexican (AAPC, 1.75%) and Asian Indians (AAPC, 6.94%) experienced annual increases. The top six underlying causes of death (155,894 cirrhosis, 38,444 CVD, 19,466 non‐liver cancer, 10,867 HCC, 8,113 DM, and 5,683 lung disease) accounted for 67.5% of NAFLD‐related deaths. For cause‐specific deaths, ASDR increased for HCC (AAPC, 3.82%), DM (AAPC, 2.23%), non‐liver cancer (AAPC, 2.14%), CVD (AAPC, 1.59%), and cirrhosis (AAPC, 0.96%). Conclusion: NAFLD‐related deaths in U.S. adults are increasing. Cirrhosis is the top cause‐specific death, followed by CVD. Women, non‐Hispanic whites, and non‐Hispanic AIANs (subgroups Mexicans and Asian Indians) experienced the highest increases in deaths. Policies addressing the societal burden of NAFLD are needed.

N-ACETYLCYSTEINE AND/OR URSODEOXYCHOLIC ACID ASSOCIATED WITH METFORMIN IN NON-ALCOHOLIC STEATOHEPATITIS: AN OPEN-LABEL MULTICENTER RANDOMIZED CONTROLLED TRIAL

BACKGROUND

Nowadays, pharmacological treatment of non-alcoholic fatty liver disease (NAFLD) is still limited and it is based on the treatment of conditions associated comorbities. Oxidative stress and insulin resistance are the mechanisms that seem to be mostly involved in its pathogenesis.

OBJECTIVE

To evaluate the efficacy of N-acetylcysteine (NAC) in combination with metformin (MTF) and/or ursodeoxycholic acid (UDCA) for treatment of non-alcoholic steatohepatitis (NASH).

METHODS

Open-label multicenter randomized trial was conducted for 48 weeks. It included patients with biopsy-proven NASH. The patients were randomized into three groups: NAC (1.2 g) + UDCA (15 mg/kg) + MTF (850-1500 mg/day) (n=26); UDCA (20 mg/kg) + MTF (850-1500 mg/day) (n=13); NAC (1.2g) + MTF (850-1500 mg/day) (n=14) for 48 weeks. Clinical, laboratory and the second liver biopsies were performed after 48 weeks.

RESULTS

A total of 53 patients were evaluated; 17 (32.1%) were males; median age ±54 (IQR=15, 21-71) years. In the baseline, no difference was seen between groups according clinical and histological parameters. The groups differed only in cholesterol, LDL and triglycerides. No significant differences in biochemical and histologic parameters were found between these the three groups after 48 weeks of treatment. In the intragroup analysis (intention-to-treat) comparing histological and biochemical features, there were significant improvements in the steatosis degree (P=0.014), ballooning (0.027) and, consequently, in the NAFLD Activity Score (NAS) (P=0.005), and in the ALT levels at the end of the treatment only in the NAC + MTF group. No significant evidence of modification in the liver fibrosis could be observed in any of the groups.

CONCLUSION

This multicenter study suggests that the association of NAC + MTF could reduce the liver disease activity in patients with NASH. These data stimulate further controlled studies with this therapy for these patients.

Long-term exercise prevents hepatic steatosis: a novel role of FABP1 in regulation of autophagy-lysosomal machinery

Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent diseases worldwide. Exercise is a first-line therapy and an important preventive measure for patients with NAFLD, but the underlying mechanisms are not clear. C57BL/6 mice were fed a high-fat diet (HFD) and subjected to 12 wk swimming exercise. Exercise protected against hepatic lipid accumulation and alleviated hepatocyte damage in HFD mice. Tandem mass tag-based quantitative proteomic analyses and ingenuity pathway analysis revealed that exercise down-regulated fatty acid-binding protein (FABP)1 signaling pathway, which was most closely associated with lipid metabolism. Moreover, exercise significantly decreased FABP1 expression, and liver-specific overexpression of FABP1 abolished the protective effect of exercise in NAFLD mice. Specifically, exercise significantly increased autophagic flux via restoring lysosomal function, including lysosomal proteolysis and lysosomal acidification maintenance, contributing to enhancement in autophagic clearance and subsequently alleviation of hepatic steatosis. Conversely, Fabp1 overexpression in the mouse liver blocked the protective effect of exercise via inhibiting autophagy flux. The present study identified FABP1 inhibition-mediated replenishment of the autophagy-lysosomal machinery as a novel endogenous mechanism whereby long-term exercise improves lipid homeostasis and ameliorates hepatic steatosis in NAFLD.-Pi, H., Liu, M., Xi, Y., Chen, M., Tian, L., Xie, J., Chen, M., Wang, Z., Yang, M., Yu, Z., Zhou, Z., Gao, F. Long-term exercise prevents hepatic steatosis: a novel role of FABP1 in regulation of autophagy-lysosomal machinery.

Nonalcoholic Fatty Liver Disease and Renal Function Impairment: A Cross-Sectional Population-Based Study on Its Relationship From 1999 to 2016

There is growing evidence that links nonalcoholic fatty liver disease (NAFLD) with impairment of renal function. As such, we aimed to demonstrate the trend of NAFLD, NAFLD with renal insufficiency (RI), disease awareness, and mortality over time. Patient data were extracted from the National Health and Nutrition Examination Survey (NHANES) 1999-2016. A total of 14,255 adult study participants without competing liver disease or heavy drinking and with complete laboratory data were included. NAFLD was defined using the U.S. Fatty Liver Index (USFLI) and RI was defined using the Chronic Kidney Disease Epidemiology Collaboration equation and urine albumin:creatinine ratio. Death data were obtained from the National Death Index (up to December 31, 2015). Prevalence of NAFLD in participants was 31.2% (95% confidence interval [CI], 30.01-32.46); of these participants, 22.05% (95% CI, 20.34-23.85) had RI. From 1999 to 2016, prevalence of both NAFLD without RI (P = 0.048) and NAFLD-RI (P = 0.006) increased significantly. Among those with NAFLD-RI, awareness of kidney disease was 8.56% (95% CI, 6.69-10.89), while awareness of liver disease among all NAFLD was 4.49% (95% CI, 3.17-6.33). Among those with NAFLD, mortality incidence per 1,000 person years was highest among those with severe RI in all-cause mortality (104.4; 95% CI, 83.65-130.39) and other residual causes of mortality (mean, 50.88; 95% CI, 37.02-69.93). Conclusion: Prevalence of NAFLD and NAFLD-RI has increased over the past 2 decades in the United States. Low kidney disease and liver disease awareness are major public health issues as those with NAFLD-RI have significantly higher mortality than those with only NAFLD.

Serum Vitamin E Levels of Adults with Nonalcoholic Fatty Liver Disease: An Inverse Relationship with All-Cause Mortality in Non-Diabetic but Not in Pre-Diabetic or Diabetic Subjects

Nonalcoholic fatty liver disease (NAFLD) is a growing health threat worldwide. Vitamin E supplementation is recommended for nonalcoholic steatohepatitis (NASH) patients, but only for non-diabetic subjects. We aimed to investigate whether serum vitamin E levels differently impact long-term prognosis in diabetic versus non-diabetic NAFLD individuals. A total of 2404 ultrasonographically defined NAFLD individuals from National Health and Nutrition Examination Survey (NHANES) III were stratified by their glycemic statuses into diabetic (N = 662), pre-diabetic (N = 836) and non-diabetic (N = 906), and the relationship between serum vitamin E levels and all-cause mortality was analyzed. The serum vitamin E concentrations were 31.1 ± 14.1, 26.7 ± 9.6, and 24.7 ± 9.8 µmol/L and vitamin E: total cholesterol ratios were 5.16 ± 1.70, 4.81 ± 1.46, and 4.80 ± 1.34 µmol/mmol in in diabetic, pre-diabetic, and non-diabetic groups, respectively. Of 2404 NAFLD subjects, 2403 have mortality information and 152 non-diabetic, 244 pre-diabetic, and 342 diabetic participants died over a median follow-up period of 18.8 years. Both serum vitamin E levels and vitamin E: total cholesterol ratios were negatively associated with all-cause mortality after adjusting for possible confounders in non-diabetic subjects (HR = 0.483, and 0.451, respectively, p < 0.005), but not in either diabetic or pre-diabetic subjects. In NAFLD individuals, both serum vitamin E and lipid-corrected vitamin E were (1) higher in the diabetic group; and (2) negatively associated with all-cause mortality only in the non-diabetic group. Further investigations are warranted to elucidate the underlying mechanism of this inverse association of serum vitamin E concentration with all-cause mortality in non-diabetic but not pre-diabetic or diabetic subjects.

Gut microbiome-targeted therapies in nonalcoholic fatty liver disease: a systematic review, meta-analysis, and meta-regression

BACKGROUND

Preclinical evidence suggests that modulation of the gut microbiome could represent a new therapeutic target in nonalcoholic fatty liver disease (NAFLD).

OBJECTIVES

The aim of this study was to evaluate the most current evidence for liver-specific and metabolic effects of microbiome-targeted therapies (MTTs) in persons with NAFLD.

METHODS

We searched multiple electronic databases for randomized controlled trials (RCTs) published from January 1, 2005 to December 1, 2018 that enrolled persons with NAFLD who received MTT rather than placebo or usual care. MTT was defined as antibiotics, probiotics, synbiotics, or fecal microbiota transplantation (FMT). Clinical outcomes were pooled with the use of random-effects models and heterogeneity was assessed with the I2 statistic. A random-effects meta-regression was performed to determine sources of heterogeneity in prevalence estimates between studies.

RESULTS

Twenty-one RCTs (1252 participants) were included; 9 evaluated probiotics and 12 evaluated synbiotics, with treatment duration ranging from 8 to 28 wk. No RCTs examined the efficacy of antibiotics or FMT. Probiotics/synbiotics were associated with a significant reduction in alanine aminotransferase activity [ALT, weighted mean difference (WMD): -11.23 IU/L; 95% CI: -15.02, -7.44 IU/L] and liver stiffness measurement (LSM) by elastography (reflecting inflammation and fibrosis) (WMD: -0.70 kPa; 95% CI: -1.00, -0.40 kPa), although analyses showed heterogeneity (I2 = 90.6% and I2 = 93.4%, respectively). Probiotics/synbiotics were also associated with increased odds of improvement in hepatic steatosis, as graded by ultrasound (OR: 2.40; 95% CI: 1.50, 3.84; I2 = 22.4%). No RCTs examined sequential liver biopsy findings. Probiotics (WMD: -1.84; 95% CI: -3.30, -0.38; I2 = 23.6%), but not synbiotics (WMD: -0.85; 95% CI: -2.17, 0.47; I2 = 96.6%), were associated with a significant reduction in body mass index.

CONCLUSIONS

The use of probiotics/synbiotics was associated with improvement in liver-specific markers of hepatic inflammation, LSM, and steatosis in persons with NAFLD. Although promising, given the heterogeneity in pooled analyses, additional well-designed RCTs are needed to define the efficacy of probiotics/synbiotics for treatment of NAFLD. This study was registered with PROSPERO as CRD42018091455.

Liver transplantation for bariatric surgery-related liver failure: a systematic review of a rare condition

BACKGROUND

Protein malnutrition and bacterial overgrowth occurring after bariatric surgery (BS) might cause severe liver failure (LF) needing liver transplantation (LT).

OBJECTIVES

To evaluate indications and outcomes of LT for BS-related LF.

SETTING

University hospital in France.

METHODS

The EMBASE, MEDLINE, and COCHRANE central databases were systematically searched according to the PRISMA criteria from inception up through December 2017 for articles describing LT for LF after BS.

RESULTS

Fourteen studies reporting 36 patients listed for LT, of which 32 underwent the procedure, were retained. The types of previously performed BS included jejunoileal bypass (n = 16), bilio-pancreatic diversion according to Scopinaro (n = 14) or with duodenal switch (n = 3), bilio-intestinal bypass (n = 1), long-limb Roux-en-Y gastric bypass (n = 1), and single anastomosis omega gastric bypass (n = 1). Liver failure developed a median of 20 months after BS (mean ± SD: 105 ± 121 mo; range, 5-300 mo). This interval of time was significantly shorter after biliopancreatic diversion than jejunoileal bypass (mean ± SD: 22 ± 21 mo versus 269 ± 27 mo; P = .0001). Four patients (11.1%) died while on the waiting list for LT, and 4 more (12.5%) died after LT. Morbidity and liver retransplantation were reported in 8 (25%) and 2 (6.2%) patients, respectively. Twenty-one patients (65.6%) had their BS procedure reversed (1 patient before, 15 patients during, and 5 patients after LT, respectively). Biopsy-proven steatosis recurrence after LT was reported in 6 patients (18.7%), 4 of whom did not have BS reversal.

CONCLUSIONS

Severe LF occurring after BS, although rare, might require LT. When indicated, LT is effective at restoring liver function, even when BS reversal is performed synchronously.

Global Perspectives on Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis

Over the past 2 decades, nonalcoholic fatty liver disease (NAFLD) has grown from a relatively unknown disease to the most common cause of chronic liver disease in the world. In fact, 25% of the world's population is currently thought to have NAFLD. Nonalcoholic steatohepatitis (NASH) is the subtype of NAFLD that can progress to cirrhosis, hepatocellular carcinoma (HCC), and death. NAFLD and NASH are not only found in adults-there is also a high prevalence of these diseases in children and adolescents. Because of the close association of NAFLD with type 2 diabetes (T2DM) and obesity, the latest models predict that the prevalence of NAFLD and NASH will increase, causing a tremendous clinical and economic burden and poor patient-reported outcomes. Nonetheless, there is no accurate noninvasive method to detect NASH, and treatment of this disease is limited to lifestyle modifications. To examine the state of NAFLD among different regions and understand the global trajectory of this disease, an international group of experts came together during the 2017 American Association for the Study of Liver Diseases Global NAFLD Forum. We provide a summary of this forum and an assessment of the current state of NAFLD and NASH worldwide.

Noninvasive monitoring of hepatic steatosis: controlled attenuation parameter and magnetic resonance imaging-proton density fat fraction in patients with nonalcoholic fatty liver disease

With an increase in the worldwide prevalence of obesity, the incidence of non-alcoholic fatty liver disease (NAFLD) has been on the rise, such that it has been recently considered to be a major public health concern. Traditional interventions, such as lifestyle modifications, regular exercise, and healthy diet, have been significant in improving NAFLD with reduction of liver fat. Areas covered: Although liver biopsy is still the gold standard for diagnosis of NAFLD, there is a need for non-invasive, quantitative assessments of hepatic steatosis, especially in clinical trials of anti-steatotic medications or in the follow-up of patients undergoing lifestyle modifications. Liver biopsy has various shortcomings, such as invasive nature, risk of complications and possibility of sampling error. Therefore, it is impractical to use liver biopsy routinely in patients with NAFLD, clearly indicating the need for non-invasive and accurate diagnostic methods. Recently, controlled attenuation parameter (CAP) and magnetic resonance imaging-proton density fat fraction (MRI-PDFF) have been employed in various studies to monitor the dynamic changes of hepatic steatosis in response to treatment in patients with NAFLD. Expert commentary: Although further validations are required, CAP and MRI-PDFF could be used as potential diagnostic and monitoring tools in clinical setting.

Genetic Insights for Drug Development in NAFLD

Drug development is a costly, time-consuming, and challenging endeavour, with only a few agents reaching the threshold of approval for clinical use. Therefore, approaches to more efficiently identify targets that are likely to translate to clinical benefit are required. Interrogation of the human genome in large patient cohorts has rapidly advanced our knowledge of the genetic architecture and underlying mechanisms of many diseases, including nonalcoholic fatty liver disease (NAFLD). There are no approved pharmacotherapies for NAFLD currently. Genetic insights provide a powerful and new approach to infer and prioritise candidate drugs, with such selection avoiding myriad pitfalls, while defining likely benefits. In this review, we discuss the prospects and challenges for the optimal utilisation of genetic findings for improving and accelerating the NAFLD drug discovery pipeline.

Temporal Trends Associated With the Rise in Alcoholic Liver Disease-related Liver Transplantation in the United States

BACKGROUND

In the United States, alcoholic liver disease (ALD) has recently become the leading indication for liver transplantation.

METHODS

Using the United Network for Organ Sharing registry, we examined temporal trends in adult liver transplant waitlist (WL) registrants and recipients with chronic liver disease (CLD) due to ALD from 2007 to 2016.

RESULTS

From 2007 to 2016, ALD accounted for 20.4% (18 399) of all CLD WL additions. The age-standardized ALD WL addition rate was 0.459 per 100 000 US population in 2007; nearly doubled to 0.872 per 100 000 US population in 2016 and increased with an average annual percent change of 47.56% (95% confidence interval, 30.33% to 64.72%).The ALD WL addition rate increased over twofold among young (18-39 years) and middle-aged (40-59 years) adults during the study period. Young adult ALD WL additions presented with a higher severity of liver disease including Model for End-Stage Liver Disease score compared to middle aged and older adults (≥60 years). The number of annual ALD WL deaths readily rose from 2014 to 2016, despite an overall annual decline in all CLD WL deaths. Severe hepatic encephalopathy, low body mass index (<18.5) and diabetes mellitus were significant predictors for 1-year WL mortality.

CONCLUSIONS

Alcoholic liver disease-related WL registrations and liver transplantation have increased over the past decade with a disproportionate increase in young and middle-aged adults. These subpopulations within the ALD cohort need to be evaluated in future studies to improve our understanding of factors associated with these alarming trends.

Endoplasmic Reticulum Stress in Metabolic Liver Diseases and Hepatic Fibrosis

Endoplasmic reticulum (ER) stress is a major contributor to liver disease and hepatic fibrosis, but the role it plays varies depending on the cause and progression of the disease. Furthermore, ER stress plays a distinct role in hepatocytes versus hepatic stellate cells (HSCs), which adds to the complexity of understanding ER stress and its downstream signaling through the unfolded protein response (UPR) in liver disease. Here, the authors focus on the current literature of ER stress in nonalcoholic and alcoholic fatty liver diseases, how ER stress impacts hepatocyte injury, and the role of ER stress in HSC activation and hepatic fibrosis. This review provides insight into the complex signaling and regulation of the UPR, parallels and distinctions between different liver diseases, and how ER stress may be targeted as an antisteatotic or antifibrotic therapy to limit the progression of liver disease.

Prevalence and long-term outcomes of non-alcoholic fatty liver disease among elderly individuals from the United States

BACKGROUND

The prevalence and outcomes of non-alcoholic fatty liver disease (NAFLD) among elderly have not been well described. Our aim was to assess the prevalence, risk factors and mortality of NAFLD in individuals older than 60 years.

METHODS

The data from the Third National Health and Nutrition Examination Survey with linked mortality files were utilized. NAFLD was defined by United States Fatty Liver Index in the absence of other causes of liver disease. Cox proportional hazards models were used to assess all-cause and cardiovascular (CV) mortality. All analyses were performed using SAS software.

RESULTS

Three thousand two hundred seventy-one NHANES-III participants were included. The prevalence rates from NAFLD were 40.3% (95% CI: 37.2-43.5%) and 39.2% (95% CI: 34.4-44.0%) among 60-74 and > 74 years old. Among aged 60-74, the risks for 5-year and 10-year all-cause mortality were associated with presence of NAFLD [adjusted hazard ratios: 1.60 (95% CI: 1.24-1.96) for 5-year and 1.22 (95%CI: 1.01-1.49) for 10-year]. CV mortality were higher in this group were (aHR: 2.12 (95% CI: 1.20-3.75) for 5-year and 1.06 (95%CI: 0.73-1.52) for 10-year]. In contrast, in individuals > 74 years old, diagnosis of NAFLD was not associated with all-cause or CVD mortality.

CONCLUSIONS

NAFLD is common among elderly population. Although NAFLD is associated with increased risk of mortality for 60-74-year-old individuals, this risk was not increased in those older than 74 years.

Lipidomic and transcriptomic analysis of western diet-induced nonalcoholic steatohepatitis (NASH) in female Ldlr -/- mice

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, particularly in obese and type 2 diabetic individuals. NAFLD ranges in severity from benign steatosis to nonalcoholic steatohepatitis (NASH); and NASH can progress to cirrhosis, primary hepatocellular carcinoma (HCC) and liver failure. As such, NAFLD has emerged as a major public health concern. Herein, we used a lipidomic and transcriptomic approach to identify lipid markers associated with western diet (WD) induced NASH in female mice.

METHODS

Female mice (low-density lipoprotein receptor null (Ldlr -/-) were fed a reference or WD diet for 38 and 46 weeks. Transcriptomic and lipidomic approaches, coupled with statistical analyses, were used to identify associations between major NASH markers and transcriptomic & lipidomic markers.

RESULTS

The WD induced all major hallmarks of NASH in female Ldlr -/- mice, including steatosis (SFA, MUFA, MUFA-containing di- and triacylglycerols), inflammation (TNFα), oxidative stress (Ncf2), and fibrosis (Col1A). The WD also increased transcripts associated with membrane remodeling (LpCat), apoptosis & autophagy (Casp1, CtsS), hedgehog (Taz) & notch signaling (Hey1), epithelial-mesenchymal transition (S1004A) and cancer (Gpc3). WD feeding, however, suppressed the expression of the hedgehog inhibitory protein (Hhip), and enzymes involved in triglyceride catabolism (Tgh/Ces3, Ces1g), as well as the hepatic abundance of C18-22 PUFA-containing phosphoglycerolipids (GpCho, GpEtn, GpSer, GpIns). WD feeding also increased hepatic cyclooxygenase (Cox1 & 2) expression and pro-inflammatory ω6 PUFA-derived oxylipins (PGE2), as well as lipid markers of oxidative stress (8-iso-PGF2α). The WD suppressed the hepatic abundance of reparative oxylipins (19, 20-DiHDPA) as well as the expression of enzymes involved in fatty epoxide metabolism (Cyp2C, Ephx).

CONCLUSION

WD-induced NASH in female Ldlr -/- mice was characterized by a massive increase in hepatic neutral and membrane lipids containing SFA and MUFA and a loss of C18-22 PUFA-containing membrane lipids. Moreover, the WD increased hepatic pro-inflammatory oxylipins and suppressed the hepatic abundance of reparative oxylipins. Such global changes in the type and abundance of hepatic lipids likely contributes to tissue remodeling and NASH severity.

Nonalcoholic Fatty Liver Disease and Diabetes: Part II: Treatment

Nonalcoholic fatty liver disease (NAFLD) and diabetes are common metabolic disorders that are often comorbid conditions. Among many proposed treatments, weight reduction is the only approved option for NAFLD to date. However, it is not easy to maintain weight loss by lifestyle modification alone; pharmacological treatments are helpful in this regard. Although many drugs have been investigated, pioglitazone could be a first-line therapy in patients with NAFLD and diabetes. Many more drugs are currently being developed and investigated, and it is likely that combination strategies will be used for future treatment of NAFLD and diabetes. Attention should be paid to the management of NAFLD and diabetes and efforts should be made to intervene early and individualize treatment of NAFLD in patients with diabetes.

Folate receptor-beta expression as a diagnostic target in human & rodent nonalcoholic steatohepatitis

INTRODUCTION

Nonalcoholic steatohepatitis (NASH) afflicts 20-36% of individuals with nonalcoholic fatty liver disease (NAFLD). A lipotoxic hepatic environment, altered innate immune signaling and inflammation are defining features of progression to NASH. Activated resident liver macrophages express folate receptor beta (FR-β) which may be an indicator of progression from steatosis to NASH. The goals of this study were to characterize FR-β protein expression in human NAFLD and rodent models of NASH, and demonstrate liver targeting of an FR-β imaging agent to the liver of a rodent NASH model using FR-β.

METHODS

Rat liver lysates from methionine choline deficient (MCD) fed rats, high fat diet (HFD) and methionine choline sufficient (MC+) rat controls were analyzed for hepatic FR-β protein. The FR-β-targeted agent, Etarfolatide was injected into MCD and MC + -fed C57BL/6 mice for efficient FastSPECT hepatic imaging. Additionally, FR-β expression across the stages of human NAFLD from normal to NASH was assessed.

RESULTS

FastSPECT images show targeting of Etarfolatide to the liver of mice fed 8 weeks of MCD diet but not control-fed mice. The MCD rat model exhibited significantly increased protein expression of hepatic FR-β in contrast to HFD or normal samples. Similarly human liver samples categorized as NASH Fatty or NASH Not Fatty showed elevated FR-β protein when compared to normal liver. FR-β transcript expression levels were elevated across both NASH Fatty and NASH Not Fatty samples.

CONCLUSION

The findings in this study indicate that FR-β expression in NASH may be harnessed to target agents directly to the liver.

Protective Effects of Ipragliflozin, a Sodium-glucose Cotransporter 2 Inhibitor, on a Non-alcoholic Steatohepatitis Mouse Model

Background

The options for the treatment of nonalcoholic steatohepatitis (NASH) are limited. We examined the effects of ipragliflozin, a sodium-glucose cotransporter 2 inhibitor, on the fatty liver Shionogi (FLS)-ob/ob mice, a non-alcoholic steatohepatitis mouse model.

Methods

FLS-ob/ob male mice were treated with vehicle (n = 10) and ipragliflozin (n = 8). Serum metabolic markers, histopathology of the liver, hepatic cholesterol and triglyceride levels and hepatic mRNA levels related to fibrosis, lipid metabolism and endoplasmic reticulum (ER) stress were compared between the two groups.

Results

The body weight and hepatic cholesterol and triglyceride levels were significantly decreased in the ipragliflozin group compared with the control group. Hepatic steatosis and fibrosis were significantly ameliorated by the treatment with ipragliflozin. Hepatic infiltration of macrophage, expression levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) and hepatic mRNA levels of ER stress markers were not significantly modulated by the treatment with ipragliflozin.

Conclusion

Ipragliflozin can be a therapeutic option for patients with NASH. The precise mechanisms of action need to be clarified in future studies.

Impact of Nutritional Changes on Nonalcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a major global health threat due to its growing incidence and prevalence. It is becoming the leading cause of liver disease in addition to its strong association with cardio-metabolic disease. Therefore, its prevention and treatment are of strong public interest. Therapeutic approaches emphasize lifestyle modifications including physical activity and the adoption of healthy eating habits that intend to mainly control body weight and cardio-metabolic risk factors associated with the metabolic syndrome. Lifestyle interventions may be reinforced by pharmacological treatment in advanced stages, though there is still no registered drug for the specific treatment of NAFLD. The purpose of this review is to assess the evidence available regarding the impact of dietary recommendations against NAFLD, highlighting the effect of macronutrient diet composition and dietary patterns in the management of NAFLD.

Dietary determinants of hepatic fat content and insulin resistance in overweight/obese children: a cross-sectional analysis of the Prevention of Diabetes in Kids (PREDIKID) study

Paediatric non-alcoholic fatty liver disease has increased in parallel with childhood obesity. Dietary habits, particularly products rich in sugars, may influence both hepatic fat and insulin resistance (homeostatic model assessment for insulin resistance (HOMA-IR)). The aim of the study was to examine the association of the consumption of foods and food components, dairy desserts and substitutes (DDS), sugar-sweetened beverages (SSB), as well as total and added sugars, with hepatic fat and HOMA-IR. Dietary intake (two non-consecutive 24 h-recalls), hepatic fat (MRI) and HOMA-IR were assessed in 110 overweight/obese children (10·6 (sd 1·1) years old). Linear regression analyses were used to examine the association of dietary intake with hepatic fat and HOMA-IR adjusted for potential confounders (sex, age, energy intake, maternal educational level, total and abdominal adiposity and sugar intake). The results showed that there was a negative association between cereal intake and hepatic fat (β=-0·197, P&lt;0·05). In contrast, both SSB consumption (β=0·217; P=0·028) and sugar in SSB (β=0·210, P=0·035), but not DDS or sugar in DDS or other dietary components, were positively associated with hepatic fat regardless of potential confounders including total sugar intake. In conclusion, cereal intake might decrease hepatic fat, whereas SSB consumption and its sugar content may increase the likelihood of having hepatic steatosis. Although these observations need to be confirmed using experimental evidence, these results suggest that healthy lifestyle intervention programs are needed to improve dietary habits as well as to increase the awareness of the detrimental effects of SSB consumption early in life.

Alcoholic and non-alcoholic steatohepatitis: global perspective and emerging science

Alcohol and high-fat diet are two major risk factors responsible for metabolic diseases, which are manifested as steatohepatitis and liver cancer in the liver, and chronic pancreatitis and pancreatic adenocarcinoma (PDAC) in the pancreas. These metabolic diseases are becoming increasingly prevalent around the globe, and more importantly, their two major etiologies commonly coexist to precipitate the disease processes. To highlight the importance of these metabolic diseases, Japanese Society of Gastroenterology (JSGE) and National Institute on Alcoholism and Alcohol Abuse of National Institute of Health cosponsored the JSGE's 7th International Forum jointly held with the 12th International Symposium on ALPD and Cirrhosis. Toward the main theme of "Frontiers in ASH, NASH, NBNC-HCC and PDAC", this platform showcased presentations by 12 invited international and Japanese speakers on brain-gut-liver interactions, emerging mechanisms of ASH and NASH, metabolic reprogramming, and new therapeutic targets for cirrhosis, HCC, and PDAC. This editorial discusses the most recent data on global statistics on how alcohol and obesity impact health and longevity as a prelude to a brief summary of the symposium presentations and discussions, primarily focusing on the first two session themes.

A Review of Non-Alcoholic Fatty Liver Disease in HIV-Infected Patients: The Next Big Thing?

The burden of liver-related morbidity remains high among HIV-infected patients, despite advances in the treatment of HIV and viral hepatitis. Especially, the impact of non-alcoholic fatty liver disease (NAFLD) is significant with a prevalence of up to 50%. The pathogenesis of NAFLD and the reasons for progression to non-alcoholic steatohepatitis (NASH) are still not fully elucidated, but insulin resistance, mitochondrial dysfunction and dyslipidemia seem to be the main drivers. Both HIV-infection itself and combination antiretroviral therapy (cART) can contribute to the development of NAFLD/NASH in various ways. As ongoing HIV-related immune activation is associated with insulin resistance, early initiation of cART is needed to limit its duration. In addition, the use of early-generation nucleoside reverse transcriptase inhibitors and protease inhibitors is also associated with the development of NAFLD/NASH. Patients at risk should therefore receive antiretroviral drugs with a more favorable metabolic profile. Only weight reduction is considered to be an effective therapy for all patients with NAFLD/NASH, although certain drugs are available for specific subgroups. Since patients with NASH are at risk of developing liver cirrhosis and hepatocellular carcinoma, several non-antifibrotic and antifibrotic drugs are under investigation in clinical trials to broaden the therapeutic options. The epidemiology and etiology of NAFLD/NASH in HIV-positive patients is likely to change in the near future. Current guidelines recommend early initiation of cART that is less likely to induce insulin resistance, mitochondrial dysfunction and dyslipidemia. In contrast, as a result of increasing life expectancy in good health, this population will adopt the more traditional risk factors for NAFLD/NASH. HIV-treating physicians should be aware of the etiology, pathogenesis and treatment of NAFLD/NASH in order to identify and treat the patients at risk.

Nonalcoholic Steatohepatitis Is the Fastest Growing Cause of Hepatocellular Carcinoma in Liver Transplant Candidates

BACKGROUND & AIMS

Although hepatitis B and C have been the main drivers of hepatocellular carcinoma (HCC), nonalcoholic steatohepatitis (NASH) has recently become an important cause of HCC. The aim of this study was to assess the causes of HCC among liver transplant (LT) candidates in the United States.

METHODS

The Scientific Registry of Transplant Recipients (2002-2016) was used to estimate the trends in prevalence of HCC in LT candidates with the most common types of chronic liver disease: alcoholic liver disease (ALD), chronic hepatitis B (CHB), chronic hepatitis C, and NASH.

RESULTS

158,347 adult LT candidates were included. Of these, 26,121 (16.5%) had HCC; this proportion increased from 6.4% (2002) to 23.0% (2016) (trend P < .0001). Over the study period, CHC remained the most common etiology for HCC (65%). The proportions of HCC accounted for by CHC and ALD remained stable (both trend P > .10), the proportion of CHB decreased 3.1-fold (P < .0001), while the proportion of NASH in HCC increased 7.7-fold (from 2.1% to 16.2%; P < .0001). Furthermore, since 2002, the prevalence of HCC in LT candidates with NASH increased 11.8-fold, while this rate increased 6.0-fold in CHB, 3.4-fold in ALD, and 2.3-fold in CHC (all P < .0001); the increasing trend in NASH was steeper than that for any other etiology (P < .0001 in a trend regression model). The proportion of LT candidates with HCC who ultimately received a transplant or died while waiting did not differ between etiologies (P > .05).

CONCLUSIONS

Nonalcoholic steatohepatitis is the most rapidly growing cause of HCC among US patients listed for liver transplantation.

Non-alcoholic fatty liver disease - A global public health perspective

As the epidemics of obesity and type 2 diabetes mellitus increase worldwide, the prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing proportionately. The subtype of NAFLD which can be characterised as non-alcoholic steatohepatitis (NASH) is a potentially progressive liver disease that can lead to cirrhosis, hepatocellular carcinoma, liver transplantation, and death. NAFLD is also associated with extrahepatic manifestations such as chronic kidney disease, cardiovascular disease and sleep apnoea. NAFLD and NASH carry a large economic burden and create poor health-related quality of life. Despite this important burden, we are only beginning to understand its mechanisms of pathogenesis and the contribution of environmental and genetic factors to the risk of developing a progressive course of disease. Research is underway to identify appropriate non-invasive diagnostic methods and effective treatments. Although the risk of liver-related mortality is increased in patients with NAFLD and liver fibrosis stages F3 or F4, the leading cause of death is cardiovascular disease. Given the rapidly growing global burden of NAFLD and NASH, efforts must continue to find accurate non-invasive diagnostic and prognostic biomarkers, to develop effective treatments for individuals with advanced NASH and prevention methods for individuals at high risk of NAFLD and progressive liver disease.

An Inhibitor of Arginine-Glycine-Aspartate-Binding Integrins Reverses Fibrosis in a Mouse Model of Nonalcoholic Steatohepatitis

The presence and stage of liver fibrosis in patients with nonalcoholic steatohepatitis (NASH) is strongly associated with mortality. Thus, both preventing and reversing fibrosis are critically important approaches to prevent death or the need for liver transplantation from NASH. Recently, fibrosis in several mouse models of organ injury was shown to be prevented and reversed with the potent small molecule, arginine-glycine-aspartic acid tripeptide (RGD)-binding, integrin antagonist (3S)-3-(3-bromo-5-(tert-butyl)phenyl)-3-(2-(3-hydroxy-5-((5-hydroxy-1,4,5,6-tetrahydropyrimidin-2-yl)amino)benzamido)acetamido)propanoic acid (Center for World Health and Medicine [CWHM]-12). We hypothesized that RGD-binding integrins may play an important role in fibrosis progression in NASH. We assessed the efficacy of CWHM-12 in a choline deficient, amino-acid defined, high-fat diet (CDAHFD) mouse model of NASH. Mice were kept on the CDAHFD or a control diet for 10 weeks, and CWHM-12 was delivered by continuous infusion for the final 4 weeks. The parameters of NASH and liver fibrosis were evaluated before and after drug treatment. Hepatic steatosis, liver injury, and inflammation were significantly induced by the CDAHFD at week 6 and did not change by week 10. Hepatic profibrogenic gene expression was induced by the CDAHFD at week 6, further increased at week 10, and decreased by CWHM-12. Fibrosis measured by analysis of liver collagen was reduced by CWHM-12 to levels significantly less than found at 6 weeks, demonstrating the possibility of reversing already established fibrosis despite ongoing injury. Demonstrated mechanisms of the antifibrotic effect of CWHM-12 included loss of activated hepatic stellate cells through apoptosis and suppression of hepatic profibrotic signal transduction by transforming growth factor β. Conclusion: RGD-binding integrins may be critical in the development of fibrosis in NASH and may represent potential targets for treating patients with NASH to reverse advanced liver fibrosis.

Concomitant PPARα and FXR Activation as a Putative Mechanism of NASH Improvement after Gastric Bypass Surgery: a GEO Datasets Analysis

BACKGROUND

Compared to non-surgical weight loss (Diet), weight loss after Roux-en-Y gastric bypass (RYGB) results in greater rates of non-alcoholic steatohepatitis (NASH) resolution. Changes in bile acid physiology and farnesoid X receptor (FXR) signaling are suspected mediators of postoperative NASH improvement. Recent experimental evidence suggests that upregulation of hepatic peroxisome proliferator-activated receptor α (PPARα) activity might also impact NASH improvement. As FXR partly regulates PPARα, we compared resolution of NASH and changes in hepatic PPARα and FXR gene expression following Diet and RYGB.

METHODS

We searched the Gene Expression Omnibus database to identify human studies with liver biopsies containing genomic data and histologic NASH features, at baseline and after Diet or RYGB. Microarray data were extracted for PPARα and FXR gene expression analyses using GEOquery R package v.2.42.0.

RESULTS

We identified one study (GSE83452) where patients underwent either Diet (n = 29) or RYGB (n = 25). NASH prevalence was similar at baseline (Diet 76% versus RYGB 60%, P = ns). After 1 year, NASH resolved in 93.3% of RYGB but only in 27.3% of Diet (P < 0.001). Hepatic PPARα and FXR gene expression increased only after RYGB (P < 0.001). These changes were also found when analyzing only patients that resolved NASH (P < 0.01), and patients without NASH at baseline and follow-up (P < 0.05).

CONCLUSIONS

Compared to Diet, RYGB results in greater NASH resolution with concurrent upregulation of hepatic PPARα and FXR. Our findings point to concurrent PPARα and FXR activation, triggered by RYGB, as a potential mechanism to improve NASH.

Patients With Lean Nonalcoholic Fatty Liver Disease Are Metabolically Abnormal and Have a Higher Risk for Mortality

IN BRIEF Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized and common cause of chronic liver disease worldwide. Although most patients with NAFLD are obese, a smaller group of NAFLD patients are lean. This study explored the long-term outcomes of lean patients with NAFLD in the United States. Compared to lean individuals without NAFLD, lean people with NAFLD were significantly more likely to be older and male and had higher comorbidities (i.e., diabetes, hyperlipidemia, hypertension, metabolic syndrome, chronic kidney disease, and cardiovascular disease). The presence of NAFLD in lean individuals was independently associated with increased risk of all-cause and cardiovascular mortality.

Extracellular Vesicles from Amnion-Derived Mesenchymal Stem Cells Ameliorate Hepatic Inflammation and Fibrosis in Rats

Background

There are no approved drug treatments for liver fibrosis and nonalcoholic steatohepatitis (NASH), an advanced stage of fibrosis which has rapidly become a major cause of cirrhosis. Therefore, development of anti-inflammatory and antifibrotic therapies is desired. Mesenchymal stem cell- (MSC-) based therapy, which has been extensively investigated in regenerative medicine for various organs, can reportedly achieve therapeutic effect in NASH via paracrine action. Extracellular vesicles (EVs) encompass a variety of vesicles released by cells that fulfill functions similar to those of MSCs. We herein investigated the therapeutic effects of EVs from amnion-derived MSCs (AMSCs) in rats with NASH and liver fibrosis.

Methods

NASH was induced by a 4-week high-fat diet (HFD), and liver fibrosis was induced by intraperitoneal injection of 2 mL/kg 50% carbon tetrachloride (CCl₄) twice a week for six weeks. AMSC-EVs were intravenously injected at weeks 3 and 4 in rats with NASH (15 μg/kg) and at week 3 in rats with liver fibrosis (20 μg/kg). The extent of inflammation and fibrosis was evaluated with quantitative reverse transcription polymerase chain reaction and immunohistochemistry. The effect of AMSC-EVs on inflammatory and fibrogenic response was investigated in vitro.

Results

AMSC-EVs significantly decreased the number of Kupffer cells (KCs) in the liver of rats with NASH and the mRNA expression levels of inflammatory cytokines such as tumor necrosis factor- (Tnf-) α, interleukin- (Il-) 1β and Il-6, and transforming growth factor- (Tgf-) β. Furthermore, AMSC-EVs significantly decreased fiber accumulation, KC number, and hepatic stellate cell (HSC) activation in rats with liver fibrosis. In vitro, AMSC-EVs significantly inhibited KC and HSC activation and suppressed the lipopolysaccharide (LPS)/toll-like receptor 4 (TLR4) signaling pathway.

Conclusions

AMSC-EVs ameliorated inflammation and fibrogenesis in a rat model of NASH and liver fibrosis, potentially by attenuating HSC and KC activation. AMSC-EV administration should be considered as a new therapeutic strategy for chronic liver disease.

Gut Microbial Metabolism and Nonalcoholic Fatty Liver Disease

The gut microbiome, the multispecies community of microbes that exists in the gastrointestinal tract, encodes several orders of magnitude more functional genes than the human genome. It also plays a pivotal role in human health, in part due to metabolism of environmental, dietary, and host‐derived substrates, which produce bioactive metabolites. Perturbations to the composition and associated metabolic output of the gut microbiome have been associated with a number of chronic liver diseases, including nonalcoholic fatty liver disease (NAFLD). Here, we review the rapidly evolving suite of next‐generation techniques used for studying gut microbiome composition, functional gene content, and bioactive products and discuss relationships with the pathogenesis of NAFLD.

Improvement of clinical management and outcome in hepatocellular carcinoma nowadays compared with historical cohorts

OBJECTIVES

Therapeutic approaches in the treatment of hepatocellular carcinoma (HCC) depend on tumour stage, liver function and patient comorbidities. The aim of this study was to investigate the influence of tumour stage and therapeutic approach on overall survival in HCC.

MATERIALS AND METHODS

Two hundred and fourteen patients with HCC diagnosed between December 2012 and May 2017 were assessed retrospectively for tumour stage [Barcelona Clinic Liver Cancer (BCLC)], liver function (Child-Pugh score), therapeutic approach and outcome (mean survival time). The results were compared to two historical cohorts from our centre diagnosed between 1999 and 2013 and 1988 and 1999, respectively.

RESULTS

Nowadays, HCC is diagnosed in earlier tumour stages and with better liver function compared with the historical cohorts (P<0.001). Survival times depend on both BCLC stages and liver function for all therapeutic approaches. The 1-year survival rate in the present cohort was 79.4% compared with 58.6% in the historical cohort.In terms of BCLC stages, therapeutic approaches followed HCC guidelines in 43.9% of cases.Whereas the percentage of patients receiving resection or ablation did not change between the historical and the present cohort, there was a tendency towards a decrease in transarterial chemoembolization, with a shift towards selective internal radiotherapy, accompanied by an increase in systemic therapy with sorafenib.Also, the percentage of patients receiving single instead of multiple therapies was significantly higher in the present cohort compared with the historical cohort (P=0.016). In 62/83 patients receiving single therapy (64.7%), tumour remission was maintained during the period of follow-up.

CONCLUSION

HCC is increasingly being diagnosed in earlier stages, so that single therapy is often sufficient. Besides BCLC stages, therapy in HCC must consider liver function, tumour location, local expertise and patients' comorbidities and preferences. Further research is needed to evaluate the benefit of early multimodal concepts. Therapeutic approaches in HCC remain individual decisions.

Targeting mitochondria to oppose the progression of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a condition characterized by the excessive accumulation of triglycerides in hepatocytes. NAFLD is the most frequent chronic liver disease in developed countries, and is often associated with metabolic disorders such as obesity and type 2 diabetes. NAFLD definition encompasses a spectrum of chronic liver abnormalities, ranging from simple steatosis (NAFL), to steatohepatitis (NASH), significant liver fibrosis, cirrhosis, and hepatocellular carcinoma. NAFLD, therefore, represents a global public health issue. Mitochondrial dysfunction occurs in NAFLD, and contributes to the progression to the necro-inflammatory and fibrotic form (NASH). Disrupted mitochondrial function is associated with a decrease in the energy levels and impaired redox balance, and negatively affects cell survival by altering overall metabolism and subcellular trafficking. Such events reduce the tolerance of hepatocytes towards damaging hits, and favour the injurious effects of extra-cellular factors. Here, we discuss the role of mitochondria in NAFLD and focus on potential therapeutic approaches aimed at preserving mitochondrial function.

Advances and challenges in the management of advanced fibrosis in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming the most common type of chronic liver disease worldwide. From the spectrum of NAFLD, it is nonalcoholic steatohepatitis (NASH) that predominantly predisposes patients to higher risk for development of cirrhosis and hepatocellular carcinoma. There is growing evidence that the risk of progression to cirrhosis and hepatocellular carcinoma is not uniform among all patients with NASH. In fact, NASH patients with increasing numbers of metabolic diseases such as diabetes, hypertension, visceral obesity and dyslipidemia are at a higher risk of mortality. Additionally, patients with higher stage of liver fibrosis are also at increased risk of mortality. In this context, NASH patients with fibrosis are in the most urgent need of treatment. Also, the first line of treatment for NASH is lifestyle modification with diet and exercise. Nevertheless, the efficacy of lifestyle modification is quite limited. Additionally, vitamin E and pioglitazone may be considered for subset of patients with NASH. There are various medications targeting one or more steps in the pathogenesis of NASH being developed. These drug regimens either alone or in combination, may provide potential treatment option for patients with NASH.

The Chinese medicine Chai Hu Li Zhong Tang protects against non-alcoholic fatty liver disease by activating AMPKα

An effective treatment for non-alcoholic fatty liver disease (NAFLD) is urgently needed. In the present study, we investigated whether the Chinese medicine Chai Hu Li Zhong Tang (CHLZT) could protect against the development of NAFLD. Rats in an animal model of NAFLD were treated with CHLZT, and their serum levels of cholesterol (TC), triglycerides (TG), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were detected with an automatic biochemical analyzer. A cellular model of NAFLD was also established by culturing HepG2 cells in a medium that contained a long chain fat emulsion. Those cells were treated with CHLZT that contained serum from rats. After treatment, the levels of adenylate-activated protein kinase (AMPK) α (AMPKα), p-AMPKα, acetyl coenzyme A carboxylase (ACC) α (ACCα), pACCα, PPARγ, and SREBP-2 were detected. The AMPK agonist, acadesine (AICAR), was used as a positive control compound. Our results showed that CHLZT or AICAR significantly decreased the serum levels of TG, TC, LDL-C, AST, ALT, and insulin in NAFLD rats, and significantly increased their serum HDL-C levels. Treatments with CHLZT or AICAR significantly decreased the numbers of lipid droplets in NAFLD liver tissues and HepG2 cells. CHLZT and AICAR increased the levels of p-AMPKα and PPARγ in the NAFLD liver tissues and HepG2 cells, but decreased the levels of ACC-α, p-ACC-α, SREBP-2, and 3-hydroxyl-3-methylglutaryl-coenzyme A reductase (HMGR). CHLZT protects against NAFLD by activating AMPKα, and also by inhibiting ACC activity, down-regulating SREBP2 and HMGR, and up-regulating PPAR-γ. Our results suggest that CHLZT might be useful for treating NAFLD in the clinic.

Among Patients With NAFLD, Treatment of Dyslipidemia Does Not Reduce Cardiovascular Mortality

Dyslipidemia is one of the common risk factors for NAFLD and is associated with cardiovascular (CV) mortality, which is the most common cause of death in NAFLD. Lipid-lowering agents (LLAs) are used to reduce CV events in the general population. Our aim was to assess whether the use of LLAs in patients with NAFLD can reduce the risk of CV mortality. We used the third National Health and Nutrition Examination Survey mortality linked files. Mortality was determined from the National Death Index records through 2011. NAFLD was diagnosed by ultrasound after exclusion of other causes of liver disease. After inclusion and exclusion, the cohort consisted of 2,566 patients with NAFLD (45.8% < 45 years of age, 52.8% male, 75.4% white). Those who were taking LLAs were more likely to be older, non-Hispanic white, and had significantly higher rates of diabetes mellitus (DM), hyperlipidemia, hypertension, metabolic syndrome, and history of CV disease (CVD) (all P< 0.01). In our multivariate analysis, DM was an independent predictor of overall mortality (adjusted hazard ratio [aHR]: 1.79 [95% confidence interval (CI): 1.40-2.30]) and CV mortality (aHR: 1.89 [95% CI: 1.08-3.30]). History of CVD was associated with both overall (aHR: 2.03 [95% CI: 1.57-2.63]) and CV mortality (aHR: 3.69 [95% CI: 2.23-6.08]). In contrast, the use of statins and other LLAs was not associated with reduction in overall (aHR = 0.95 [95% CI: 0.37-2.44] and aHR = 1.43 [95% CI: 0.99-2.07]) and CV mortality (aHR = 1.20 [95% CI: 0.26-5.54] and aHR = 1.63 [95% CI: 0.70-3.76]). Conclusion: The use of statins and other LLAs did not reduce the increased risk of overall or CV mortality in NAFLD.

Emerging Therapeutic Targets and Experimental Drugs for the Treatment of NAFLD

The two main subsets of nonalcoholic fatty liver disease (NAFLD) include: (1) nonalcoholic fatty liver (NAFL), the more common and non-progressive subtype; and (2) nonalcoholic steatohepatitis (NASH), the less common subtype, which has the potential to progress to advanced liver damage. Current treatment strategies have focused on lifestyle management of modifiable risk factors, namely weight, and on the optimization of the management of individual components of metabolic syndrome. Various hypothetical pathogenic mechanisms have been proposed, leading to the development of novel drugs with the potential to effectively treat patients with NASH. Numerous clinical trials are ongoing, utilizing these experimental drugs and molecules targeting specific mechanistic pathway(s) to effectively treat NASH. Some of these mechanistic pathways targeted by experimental pharmacologic agents include chemokine receptor 2 and 5 antagonism, inhibition of galectin-3 protein, antagonism of toll-like receptor 4, variation of fibroblast growth factor 19, agonism of selective thyroid hormone receptor-beta, inhibition of apoptosis signal-regulating kinase 1, inhibition of acetyl-coenzyme A carboxylase, agonism of farnesoid X receptor, antibodies against lysl oxidase-like-2, and inhibition of inflammasomes. Emerging data are promising and further updates from ongoing clinical trials are eagerly awaited.

Dissociation of Fatty Liver and Insulin Resistance in I148M PNPLA3 Carriers: Differences in Diacylglycerol (DAG) FA18:1 Lipid Species as a Possible Explanation

Fatty liver is tightly associated with insulin resistance and the development of type 2 diabetes. I148M variant in patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene is associated with high liver fat but normal insulin sensitivity. The underlying mechanism of the disassociation between high liver fat but normal insulin sensitivity remains obscure. We investigated the effect of I148M variant on hepatic lipidome of subjects with or without fatty liver, using the Lipidyzer method. Liver samples of four groups of subjects consisting of normal liver fat with wild-type PNPLA3 allele (group 1); normal liver fat with variant PNPLA3 allele (group 2); high liver fat with wild-type PNPLA3 allele (group 3); high liver fat with variant PNPLA3 allele (group 4); were analyzed. When high liver fat to normal liver fat groups were compared, wild-type carriers (group 3 vs. group 1) showed similar lipid changes compared to I148M PNPLA3 carriers (group 4 vs. group 2). On the other hand, in wild-type carriers, increased liver fat significantly elevated the proportion of specific DAGs (diacylglycerols), mostly DAG (FA18:1) which, however, remained unchanged in I148M PNPLA3 carriers. Since DAG (FA18:1) has been implicated in hepatic insulin resistance, the unaltered proportion of DAG (FA18:1) in I148M PNPLA3 carriers with fatty liver may explain the normal insulin sensitivity in these subjects.

Bile Acids Activated Receptors Regulate Innate Immunity

Once known exclusively for their role in nutrients absorption, primary bile acids, chenodeoxycholic and cholic acid, and secondary bile acids, deoxycholic and lithocholic acid, are signaling molecules, generated from cholesterol breakdown by the interaction of the host and intestinal microbiota, acting on several receptors including the G protein-coupled bile acid receptor 1 (GPBAR1 or Takeda G-protein receptor 5) and the Farnesoid-X-Receptor (FXR). Both receptors are placed at the interface of the host immune system with the intestinal microbiota and are highly represented in cells of innate immunity such as intestinal and liver macrophages, dendritic cells and natural killer T cells. Here, we review how GPBAR1 and FXR modulate the intestinal and liver innate immune system and contribute to the maintenance of a tolerogenic phenotype in entero-hepatic tissues, and how regulation of innate immunity might help to explain beneficial effects exerted by GPBAR1 and FXR ligands in immune and metabolic disorders.

Zinc alpha2 glycoprotein protects against obesity-induced hepatic steatosis

BACKGROUND/AIM

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis, impaired insulin sensitivity, and chronic low-grade inflammation. Our previous studies indicated that zinc alpha2 glycoprotein (ZAG) alleviates palmitate (PA)-induced intracellular lipid accumulation in hepatocytes. This study is to further characterize the roles of ZAG on the development of hepatic steatosis, insulin resistance (IR), and inflammation.

METHODS

ZAG protein levels in the livers of NAFLD patients, high-fat diet (HFD)-induced or genetically (ob/ob) induced obese mice, and in PA-treated hepatocytes were determined by western blotting. C57BL/6J mice injected with an adenovirus expressing ZAG were fed HFD for indicated time to induce hepatic steatosis, IR, and inflammation, and then biomedical, histological, and metabolic analyses were conducted to identify pathologic alterations in these mice. The molecular mechanisms underlying ZAG-regulated hepatic steatosis were further explored and verified in mice and hepatocytes.

RESULTS

ZAG expression was decreased in NAFLD patient liver biopsy samples, obese mice livers, and PA-treated hepatocytes. Simultaneously, ZAG overexpression alleviated intracellular lipid accumulation via upregulating adiponectin and lipolytic genes (FXR, PPARα, etc.) while downregulating lipogenic genes (SREBP-1c, LXR, etc.) in obese mice as well as in cultured hepatocytes. ZAG improved insulin sensitivity and glucose tolerance via activation of IRS/AKT signaling. Moreover, ZAG significantly inhibited NF-ĸB/JNK signaling and thus resulting in suppression of obesity-associated inflammatory response in hepatocytes.

CONCLUSIONS

Our results revealed that ZAG could protect against NAFLD by ameliorating hepatic steatosis, IR, and inflammation.

Cardiometabolic effects of antidiabetic drugs in non-alcoholic fatty liver disease

PURPOSE

Non-alcoholic fatty liver disease (NAFLD) affects about 25% of the population worldwide. NAFLD may be viewed as the hepatological manifestation of metabolic syndrome. Patients with metabolic syndrome due to diabetes or obesity have an increased risk of cardiovascular disease. This narrative review describes cardiometabolic effects of antidiabetic drugs in NAFLD.

METHODS

We conducted a systematic search in PubMed and manually scanned bibliographies in trial databases and reference lists in relevant articles.

RESULTS

Heart disease is the leading cause of death in NAFLD. Conversely, NAFLD is an independent cardiovascular risk factor in patients suffering from metabolic syndrome. NAFLD is associated with markers of atherosclerosis, and patients have increased risk of ischaemic heart disease. Additionally, patients with NAFLD have increased risk of cardiac dysfunction and heart failure. There are no randomized controlled trials showing clear effects of medical treatment on clinical outcomes in patients with NAFLD. However, based on evidence from small trials and extrapolation from trials evaluating patients with type 2 diabetes, some antidiabetic drugs may be beneficial on cardiovascular function in patients with NAFLD.

CONCLUSION

At present, there is promising evidence of a potential effect of antidiabetic drugs for patients with NAFLD. Future studies should address the treatment of NAFLD and the liver-related consequences but also aim at improving the cardiometabolic outcomes.