Can NASH lipidome provide insight into the pathogenesis of obesity-related non-alcoholic fatty liver disease?

The Ameliorating Effects of n-3 Polyunsaturated Fatty Acids on Liver Steatosis Induced by a High-Fat Methionine Choline-Deficient Diet in Mice

The pathogenesis of non-alcoholic fatty liver disease (NAFLD) is associated with abnormalities of liver lipid metabolism. On the contrary, a diet enriched with n-3 polyunsaturated fatty acids (n-3-PUFAs) has been reported to ameliorate the progression of NAFLD. The aim of our study was to investigate the impact of dietary n-3-PUFA enrichment on the development of NAFLD and liver lipidome. Mice were fed for 6 weeks either a high-fat methionine choline-deficient diet (MCD) or standard chow with or without n-3-PUFAs. Liver histology, serum biochemistry, detailed plasma and liver lipidomic analyses, and genome-wide transcriptome analysis were performed. Mice fed an MCD developed histopathological changes characteristic of NAFLD, and these changes were ameliorated with n-3-PUFAs. Simultaneously, n-3-PUFAs decreased serum triacylglycerol and cholesterol concentrations as well as ALT and AST activities. N-3-PUFAs decreased serum concentrations of saturated and monounsaturated free fatty acids (FAs), while increasing serum concentrations of long-chain PUFAs. Furthermore, in the liver, the MCD significantly increased the hepatic triacylglycerol content, while the administration of n-3-PUFAs eliminated this effect. Administration of n-3-PUFAs led to significant beneficial differences in gene expression within biosynthetic pathways of cholesterol, FAs, and pro-inflammatory cytokines (IL-1 and TNF-α). To conclude, n-3-PUFA supplementation appears to represent a promising nutraceutical approach for the restoration of abnormalities in liver lipid metabolism and the prevention and treatment of NAFLD.

The Effect of Mycotoxins and Silymarin on Liver Lipidome of Mice with Non-Alcoholic Fatty Liver Disease

Milk thistle-based dietary supplements have become increasingly popular. The extract from milk thistle (Silybum marianum) is often used for the treatment of liver diseases because of the presence of its active component, silymarin. However, the co-occurrence of toxic mycotoxins in these preparations is quite frequent as well. The objective of this study was to investigate the changes in composition of liver lipidome and other clinical characteristics of experimental mice fed by a high-fat methionine-choline deficient diet inducing non-alcoholic fatty liver disease. The mice were exposed to (i) silymarin, (ii) mycotoxins (trichothecenes, enniatins, beauvericin, and altertoxins) and (iii) both silymarin and mycotoxins, and results were compared to the controls. The liver tissue extracts were analyzed by ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry. Using tools of univariate and multivariate statistical analysis, we were able to identify 48 lipid species from the classes of diacylglycerols, triacylglycerols, free fatty acids, fatty acid esters of hydroxy fatty acids and phospholipids clearly reflecting the dysregulation of lipid metabolism upon exposure to mycotoxin and/or silymarin.

Oxidative Stress Linked Organ Lipid Hydroperoxidation and Dysregulation in Mouse Model of Nonalcoholic Steatohepatitis: Revealed by Lipidomic Profiling of Liver and Kidney

Nonalcoholic steatohepatitis (NASH) is a prevalent disease related to lipid metabolism disorder and oxidative stress. Lipid hydroperoxidation is known to be a critical driving force of various disorders and diseases. However, the combination of both intact and hydroperoxidized lipids in NASH has not yet been studied. In this work, the liver and kidney samples from NASH-model mice were comprehensively investigated by using the LC/MS-based lipidomic analysis. As a result, triglycerides showed the amount accumulation and the profile alteration for the intact lipids in the NASH group, while phosphatidylethanolamines, lysophosphatidylethanolamines, plasmalogens, and cardiolipins largely depleted, suggesting biomembrane damage and mitochondria dysfunction. Notably, the lipid hydroperoxide species of triglyceride and phosphatidylcholine exhibited a significant elevation in both the liver and the kidney of the NASH group and showed considerable diagnostic ability. Furthermore, the relationship was revealed between the lipid metabolism disturbance and the lipid hydroperoxide accumulation, which played a key role in the vicious circle of NASH. The present study suggested that the omics approach to the lipid hydroperoxide profile might be the potential diagnostic marker of NASH and other oxidative stress-related diseases, as well as the evaluative treatment index of antioxidants.

The Stomach as an Endocrine Organ: Expression of Key Modulatory Genes and Their Contribution to Obesity and Non-alcoholic Fatty Liver Disease (NAFLD)

PURPOSE OF REVIEW

Obesity is currently seen in epidemic proportions globally and is one of the largest contributors to the development of NAFLD. The spectrum of NAFLD, particularly the progressive forms of NASH, is likely to become the leading cause of liver disease in the next decade.

RECENT FINDINGS

Soluble molecules, encoded by the stomach tissue, have been shown to have pleiotropic effects in both central and peripheral systems involved in energy homeostasis and obesity regulation. As such, the stomach is one of the important players in the complex, multi-system deregulation leading to obesity and NAFLD. The understanding of the stomach tissue as an active endocrine organ that contributes to the signaling milieu leading to the development of obesity and NAFLD is crucial.

Analogy between non-alcoholic steatohepatitis (NASH) and hypertension: a stepwise patient-tailored approach for NASH treatment

Non-alcoholic steatohepatitis (NASH) is a common liver disorder worldwide. Although there has been improvement in our understanding of the natural history and pathogenesis of the disease, there is still no approved therapy for NASH. NASH shares many similarities with primary hypertension, in that both are extremely common disorders that can easily lead to serious complications if left untreated. Both conditions are viewed as "silent killers", because the disease can progress over a period of time prior to the occurrence of potentially deadly outcomes. While attempts to find the "miracle pill" for NASH are unrealistic, we can make an analogy with the "stepwise combination" approach developed over the last few decades for the treatment of hypertension. In the present review, we summarize some of the similarities in the concepts that underlie NASH and hypertension. The development of a stepwise patient-tailored method for the treatment of NASH is presented.

The novel intracellular protein CREG inhibits hepatic steatosis, obesity, and insulin resistance

Cellular repressor of E1A-stimulated genes (CREG), a novel cellular glycoprotein, has been identified as a suppressor of various cardiovascular diseases because of its capacity to reduce hyperplasia, maintain vascular homeostasis, and promote endothelial restoration. However, the effects and mechanism of CREG in metabolic disorder and hepatic steatosis remain unknown. Here, we report that hepatocyte-specific CREG deletion dramatically exacerbates high-fat diet and leptin deficiency-induced (ob/ob) adverse effects such as obesity, hepatic steatosis, and metabolic disorders, whereas a beneficial effect is conferred by CREG overexpression. Additional experiments demonstrated that c-Jun N-terminal kinase 1 (JNK1) but not JNK2 is largely responsible for the protective effect of CREG on the aforementioned pathologies. Notably, JNK1 inhibition strongly prevents the adverse effects of CREG deletion on steatosis and related metabolic disorders. Mechanistically, CREG interacts directly with apoptosis signal-regulating kinase 1 (ASK1) and inhibits its phosphorylation, thereby blocking the downstream MKK4/7-JNK1 signaling pathway and leading to significantly alleviated obesity, insulin resistance, and hepatic steatosis. Importantly, dramatically reduced CREG expression and hyperactivated JNK1 signaling was observed in the livers of nonalcoholic fatty liver disease (NAFLD) patients, suggesting that CREG might be a promising therapeutic target for NAFLD and related metabolic diseases.

CONCLUSION

The results of our study provides evidence that CREG is a robust suppressor of hepatic steatosis and metabolic disorders through its direct interaction with ASK1 and the resultant inactivation of ASK1-JNK1 signaling. This study offers insights into NAFLD pathogenesis and its complicated pathologies, such as obesity and insulin resistance, and paves the way for disease treatment through targeting CREG. (Hepatology 2017;66:834-854).

Variables Associated With Inpatient and Outpatient Resource Utilization Among Medicare Beneficiaries With Nonalcoholic Fatty Liver Disease With or Without Cirrhosis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is one of the leading causes of chronic liver disease worldwide with tremendous clinical burden. The economic burden of NAFLD is not well studied.

GOAL

To assess the economic burden of NAFLD.

STUDY

Medicare beneficiaries (January 1, 2010 to December 31, 2010) with NAFLD diagnosis by International Classification of Diseases, Ninth Revision codes in the absence of other liver diseases were selected. Inpatient and outpatient resource utilization parameters were total charges and total provider payments. NAFLD patients with compensated cirrhosis (CC) were compared with decompensated cirrhosis (DC).

RESULTS

A total of 976 inpatients and 4742 outpatients with NAFLD were included-87% were white, 36% male, 30% had cardiovascular disease (CVD) or metabolic syndrome conditions, and 12% had cirrhosis. For inpatients, median total hospital charge was $36,289. NAFLD patients with cirrhosis had higher charges and payments than noncirrhotic NAFLD patients ($61,151 vs. $33,863 and $18,804 vs. $10,146, P<0.001). Compared with CC, NAFLD patients with DC had higher charges and payments (P<0.02). For outpatients, median total charge was $9,011. NAFLD patients with cirrhosis had higher charges and payments than noncirrhotic NAFLD patients ($12,049 vs. $8,830 and $2,586 vs. $1,734, P<0.001). Compared with CC, DC patients had higher total charges ($15,187 vs. $10,379, P=0.04). In multivariate analysis, variables associated with increased inpatient resource utilization were inpatient mortality, DC, and CVD; for outpatients, having CVD, obesity, and hypertension (all P<0.001).

CONCLUSIONS

NAFLD is associated with significant economic burden to Medicare. Presence of cirrhosis and CVD are associated with increased resource utilization.

Calycosin attenuates triglyceride accumulation and hepatic fibrosis in murine model of non-alcoholic steatohepatitis via activating farnesoid X receptor

BACKGROUND

Non-alcoholic steatohepatitis (NASH) represents the more severe end of hepatic steatosis and is associated with progressive liver disease. Calycosin, derived from the root of Radix Astragali, has been demonstrated to have favorable efficacy on acute liver injury.

PURPOSE

The present study was to investigate the hepatoprotective effect of calycosin on attenuating triglyceride accumulation and hepatic fibrosis, as well as explore the potential mechanism in murine model of NASH.

STUDY DESIGN

The C57BL/6 male mice were fed with methionine choline deficient (MCD) diet for 4 weeks to induce NASH and treated with or without calycosin by oral gavage for 4 weeks.

METHODS

The body weight, liver weight and the liver to body weight ratios were measured. Serum ALT, AST, TG, TC, FFA, MCP-1 and mKC levels were accessed by biochemical methods. H&E staining and Oil red O staining were used to identify the amelioration of liver histopathology. Immunohistochemistry of a-SMA, Masson trichrome staining and Sirius red staining were used to identify the amelioration of hepatic fibrosis. The quantitative real-time-PCR and Western blot were applied to observe the expression changes of key factors involved in triglyceride synthesis, free fatty acid β-oxidation and hepatic fibrosis.

RESULTS

Calycosin significantly inhibited body weight loss induced by MCD diet, decreased the ALT and AST activities, MCP-1 and mKC in a dose-dependent manner. The H&E and Oil red O staining indicated calycosin effectively improved hepatic steatosis, improved the degree of triglyceride accumulation. Masson trichrome and Sirius red staining indicated that calycosin treatment remarkably attenuated the degree of hepatic fibrosis. Immunohistochemistry of a-SMA demonstrated that calycosin attenuated hepatic fibrosis by inhibiting hepatic stellate cell activation. Further, calycosin inhibited the expression of SREBP-1c, FASN, ACC and SCD1 involved in triglyceride synthesis, promoted the expression of PPARa, CPT1, Syndecan-1 and LPL involved in free fatty acid β-oxidation. The above effects of calycosin were attributed to FXR activation.

CONCLUSION

Calycosin attenuates triglyceride accumulation and hepatic fibrosis to protect against NASH via FXR activation.

Protective effects of glycyrrhizic acid from edible botanical glycyrrhiza glabra against non-alcoholic steatohepatitis in mice

Glycyrrhizic acid protects against non-alcoholic steatohepatitis in mice.