Non-alcoholic steatohepatitis patients exhibit reduced CD47, and increased sphingosine, cholesterol and MCP1 levels in the erythrocyte membranes

Non-alcoholic steatohepatitis (NASH) constitutes a significant cause of deaths, liver transplantations and economic costs worldwide. Despite extended research, investigations on the role of erythrocytes are scarce. Red blood cells from experimental animals and human patients with NASH, present phosphatidylserine exposure which is then recognized by Kupffer cells. This event leads to erythrophagocytosis, and amplification of inflammation through iron disposition. In addition, it has been shown that erythrocytes from NASH patients release the chemokine MCP1, leading to increased TNF-α release from macrophages RAW 264.7. However, erythrophagocytosis can also be caused by reduced CD47 levels. In addition, increased MCP1 release could be either signal-induced, or caused by higher MCP1 levels on the erythrocyte membrane. Finally, erythrocyte efferocytosis could provide additional inflammatory metabolites. In this study, we measured the erythrocyte membrane levels of CD47 and MCP1 by ELISA, and cholesterol and sphingosine with thin-layer chromatography. 18 patients (8 men, 10 women aged 56.7+/-11.5 years) and 14 healthy controls (7 men, 7 women aged 39.3+/-15.5 years) participated in our study. The erythrocyte CD47 levels were decreased in the erythrocyte membranes of NASH patients (844+/-409 pg/ml) compared to healthy controls (2969+/-1936 pg/ml) with P(Healthy>NAFLD)=99.1%, while the levels of MCP1 were increased in NASH patients (389+/-255 pg/ml), compared to healthy controls (230+/-117 pg/ml) with P(Healthy<NAFLD)=88.9%. Moreover, in erythrocyte membranes there was a statistically significant accumulation of sphingosine and cholesterol in NASH patients, compared to healthy controls. Our results imply that erythrocytes release chemotactic (find me signals) MCP1, while containing reduced (do not eat me signals) CD47. These molecules can lead to erythrophagocytosis. Next, increased (goodbye signals) sphingosine and cholesterol could augment inflammation by metabolic reprogramming.

Chemerin Overexpression in the Liver Protects against Inflammation in Experimental Non-Alcoholic Steatohepatitis

Non-alcoholic steatohepatitis (NASH) is marked by macrophage infiltration and inflammation. Chemerin is a chemoattractant protein and is abundant in hepatocytes. The aim of this study was to gain insight into the role of hepatocyte-produced prochemerin in NASH. Therefore, mice were infected with adeno-associated virus 8 to direct hepatic overexpression of prochemerin in a methionine–choline deficient dietary model of NASH. At the end of the study, hepatic and serum chemerin were higher in the chemerin-expressing mice. These animals had less hepatic oxidative stress, F4/80 and CC-chemokine ligand 2 (CCL2) protein, and mRNA levels of inflammatory genes than the respective control animals. In order to identify the underlying mechanisms, prochemerin was expressed in hepatocytes and the hepatic stellate cells, LX-2. Here, chemerin had no effect on cell viability, production of inflammatory, or pro-fibrotic factors. Notably, cultivation of human peripheral blood mononuclear cells (PBMCs) in the supernatant of Huh7 cells overexpressing chemerin reduced CCL2, interleukin-6, and osteopontin levels in cell media. CCL2 was also low in RAW264.7 cells exposed to Hepa1–6 cell produced chemerin. In summary, the current study showed that prochemerin overexpression had little effect on hepatocytes and hepatic stellate cells. Of note, hepatocyte-produced chemerin deactivated PBMCs and protected against inflammation in experimental NASH.

Drug Therapy for Non-Alcoholic Steatohepatitis-Induced Liver Fibrosis

Aim. An overview of current pharmacotherapy for non-alcoholic steatohepatitis (NASH)-associated liver fibrosis.Key points. In current clinical recommendations, therapeutic measures in non-alcoholic fatty liver disease should include lifestyle change, body weight normalisation, NASH-associated liver fibrosis-specific drug therapy and treatment for metabolic syndrome-related diseases. Given a lack of approved antifibrotic therapies in NASH, several drugs have nevertheless demonstrated an adequate efficacy and safety in phase 3 clinical trials, also in compensated cirrhosis, which allows their practical validation in phase 4.Conclusion. The understanding of liver fibrosis as an adverse natural consequence of non-alcoholic fatty liver disease clearly attests for an early introduction and wide use of antifibrotic therapy to improve NASH outcomes and avoid associated complications.

Non-Alcoholic Steatohepatitis (NASH) and Organokines: What Is Now and What Will Be in the Future

Non-alcoholic steatohepatitis (NASH) is characterized by steatosis, lobular inflammation, and enlargement of the diameter of hepatocytes (ballooning hepatocytes), with or without fibrosis. It affects 20% of patients with non-alcoholic fatty liver disease (NAFLD). Due to liver dysfunction and the numerous metabolic changes that commonly accompany the condition (obesity, insulin resistance, type 2 diabetes, and metabolic syndrome), the secretion of organokines is modified, which may contribute to the pathogenesis or progression of the disease. In this sense, this study aimed to perform a review of the role of organokines in NASH. Thus, by combining descriptors such as NASH, organokines, oxidative stress, inflammation, insulin resistance, and dyslipidemia, a search was carried out in the EMBASE, MEDLINE-PubMed, and Cochrane databases of articles published in the last ten years. Insulin resistance, inflammation and mitochondrial dysfunction, fructose, and intestinal microbiota were factors identified as participating in the genesis and progression of NASH. Changes in the pattern of organokines secretion (adipokines, myokines, hepatokines, and osteokines) directly or indirectly contribute to aggravating the condition or compromise homeostasis. Thus, further studies involving skeletal muscle, adipose, bone, and liver tissue as endocrine organs are essential to better understand the modulation of organokines involved in the pathogenesis of NASH to advance in the treatment of this disease.

Exercise Alleviates the Apolipoprotein A5-Toll-Like Receptor 4 Axis Impairment in Mice With High-Fat Diet-Induced Non-alcoholic Steatohepatitis

Background: Apolipoprotein A5 (ApoA5), an important modulator of plasma and hepatic triglyceride metabolism, has been found to be downregulated by metformin to improve non-alcoholic fatty liver disease. Meanwhile, exercise has been recommended as a therapeutic strategy for non-alcoholic steatohepatitis (NASH). However, no study has yet determined whether exercise affects hepatic ApoA5 expression or the inhibition of ApoA5 to toll-like receptor 4 (TLR4). We herein examined the effects of exercise on hepatic ApoA5 expression and the relevance of ApoA5 and TLR4-mediated pathway in mice with high-fat diet (HFD)-induced NASH.Methods: Male C57BL/6J mice were built NASH model with high-fat diet for 12 weeks, and following mice were subjected to exercise for 12 weeks on a treadmill. Microscopy and enzyme-linked immunosorbent assay were used to measure histological analysis of liver and hepatic lipids, respectively. Quantitative real-time PCR and western blot were used to determined mRNA and protein levels of ApoA5 and TLR4-mediated nuclear factor kappa B (NF-κB) pathway components, respectively. ApoA5 overexpression plasmids transfected into mice to investigate the relevance of ApoA5 and TLR4.Results: 12 weeks of exercise remarkably alleviated HFD-induced hepatic lipid accumulation, inflammation, and fibrosis, as well as reduced serum lipopolysaccharide (LPS), hepatic TLR4, myeloid differentiation factor 88 (MyD88), and NF-κBp65 expression. Importantly, exercise did not reduce ApoA5 expression but instead enhanced its ability to suppress TLR4-mediated NF-κB pathway components by decreasing circulating LPS in our experiments involving transfection of ApoA5 overexpression plasmids and LPS interventions.Conclusion: The results demonstrated that exercise improved HFD-induced NASH by triggering the inhibitory effects of ApoA5 on the TLR4-mediated NF-κB pathway.

Changes in rat liver fatty acid profile in experimental non-alcoholic steatohepatitis

Introduction. Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the world. Non-alcoholic steatohepatitis (NASH), a clinically progressive morphological form of NAFLD, ranks second in the list of reasons for liver transplantation in the adult population. In the pathogenesis of this disease, metabolism and distribution of free fatty acids (FFA) play an important role. A large number of studies have established that the level of FFA in peripheral blood directly correlates with the severity of NASH, but it is still unclear what effect fluctuations in the profile of fatty acids (FA) in the liver have in steatohepatitis.Aim. Study of changes in the profile of fatty acids in the liver of laboratory animals with experimental non-alcoholic steatohepatitis.Materials and methods. The study was carried out on 17 white outbred male rats, which were randomized into two groups – intact (n = 6) and control (steatohepatitis) (n = 11). Steatohepatitis was modeled by 12-month use of a hypercaloric high-fat diet against the background of hypodynamia. The content of fatty acids in the liver was determined in the reaction of methanolysis and extraction with a hexane mixture of their methyl esters. The LC was separated by gas chromatography-mass spectrometry. Calibration for quantitative calculation was carried out with deuterated tridecanoic acid. The content of saturated and monounsaturated higher FAs, their aldehydes and hydroxy derivatives, as well as sterols were studied.Results and discussion. A total decrease in the content of FFA in the liver of animals with steatohepatitis was revealed. The most significant decrease occurred mainly in the class of monounsaturated fatty acids and cholesterol. Also, a significant decrease in the activity of Δ9-desaturase, a key enzyme in the synthesis of monounsaturated FAs from their precursor with the same carbon chain length, was revealed, which was manifested by a significant decrease in their amount in the liver. There were no statistically significant changes in the levels of aldehydes and hydroxy acids between the study groups, as well as in the level of sterols (except for cholesterol, the content of which decreased significantly).Conclusion. Thus, in the liver of rats with steatohepatitis caused by a combination of a hypercaloric diet and hypodynamia, statistically significant changes in the profile and concentration of fatty acids were found in comparison with healthy animals. The demonstrated shifts in FA composition may reflect both adaptive and pathological changes in the liver of animals with NAFLD and require further study.