Inflammation-associated interleukin-6/signal transducer and activator of transcription 3 activation ameliorates alcoholic and nonalcoholic fatty liver diseases in interleukin-10-deficient mice

Graveoline attenuates D-GalN/LPS-induced acute liver injury via inhibition of JAK1/STAT3 signaling pathway

Graveoline exhibits various biological activities. However, only limited studies have focused on its hepatoprotective properties. This study evaluated the anti-inflammatory and hepatoprotective activities of graveoline, a minor 2-phenylquinolin-4-one alkaloid isolated from Ruta graveolens L., in a liver injury model in vitro and in vivo. A network pharmacology approach was used to investigate the potential signaling pathway associated with the hepatoprotective activity of graveoline. Subsequently, biological experiments were conducted to validate the findings. Topological analysis of the KEGG pathway enrichment revealed that graveoline mediates its hepatoprotective activity through genes associated with the hepatitis B viral infection pathway. Biological experiments demonstrated that graveoline effectively reduced the levels of alanine transaminase and aspartate transaminase in lipopolysaccharide (LPS)-induced HepG2 cells. Graveoline exerted antihepatitic activity by inhibiting the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) and elevated the anti-inflammatory cytokines interleukin-4 (IL-4) and interleukin-10 (IL-10) in vitro and in vivo. Additionally, graveoline exerted its hepatoprotective activity by inhibiting JAK1 and STAT3 phosphorylation both in vitro and in vivo. In summary, graveoline can attenuate acute liver injury by inhibiting the TNF-α inflammasome, activating IL-4 and IL-10, and suppressing the JAK1/STAT3 signaling pathway. This study sheds light on the potential of graveoline as a promising therapeutic agent for treating liver injury.

Inflammation in Alcohol-Associated Hepatitis: Pathogenesis and Therapeutic Targets

Alcohol-associated hepatitis (AH) is an acute-on-chronic liver injury that occurs in patients with chronic alcohol-associated liver disease (ALD). Patients with severe AH have high short-term mortality and lack effective pharmacologic therapies. Inflammation is believed to be one of the key factors promoting AH progression and has been actively investigated as therapeutic targets over the last several decades, but no effective inflammatory targets have been identified so far. In this review, we discuss how inflammatory cells and the inflammatory mediators produced by these cells contribute to the development and progression of AH, with focus on neutrophils and macrophages. The crosstalk between inflammatory cells and liver nonparenchymal cells in the pathogenesis of AH is elaborated. We also deliberate the application of recent cutting-edge technologies in characterizing liver inflammation in AH. Finally, the potential therapeutic targets of inflammatory mediators for AH are briefly summarized.

Costunolide mitigates inflammation and promotes extracellualr matrix integrity of thoracic aortic dissection by inhibiting NF-κB signaling

BACKGROUND

Thoracic aortic dissection (TAD) is one of the most fatal cardiovascular diseases. One of its important pathological characteristics is the local inflammatory response. Many studies have found that Macrophage polarization plays an extremely critical role in the inflammatory progression and tissue remodeling of TAD. Costunolide (CTD) has an improving effect on oxidative stress and inflammation in the body. However, whether it can promote the integrity of extracellular matrix in Aortic dissection and its mechanism are still unclear.

METHODS

The male C57BL/6J mice were used to construct an animal model of TAD with β-aminopropionitrile (BAPN) (100 mg/kg/day, lasting for 28 days), and then CTD (10 mg/kg or 100 mg/kg) was injected intraperitoneally for 28 days to check the survival rate, TAD incidence, aortic morphology and other indicators of the mice. Using hematoxylin-eosin (HE), Masson, Elastin van Gieson (EVG) staining, immunofluorescence (IF), and immunohistochemical staining, the study aimed to determine the therapeutic effects of CTD on an animal model with BAPN-induced TAD. To enhance the examination of the regulatory mechanism of CTD, we conducted transcriptome sequencing on arterial tissues of mice in both the BAPN group and the BAPN + CTD100 group. Next, ANG II were used to construct TAD model in vascular smooth muscle cells (VMSCs). The effects of CTD on the proliferation, migration, invasion, and apoptosis of ANG II-induced cells are to be detected. The expression of MMP2, MMP9, P65, and p-P65 in each group will be examined using Western blot. Finally, the overexpression of IκB kinaseβ (IKKβ) will be established in VMSCs cells to further explore the protective function of CTD.

RESULTS

The result showed that CTD significantly inhibited BAPN induced mortality and TAD incidence in the animal model, improved aortic vascular morphology, promoted the integrity of extracellular matrix in TAD, reduced tissue inflammation, reduced the accumulation of M1 macrophage, promoted M2 macrophage polarization, and reduced the expression of NF-κB pathway related proteins. Mechanistically, CTD significantly weakened the proliferation, migration, invasion, and apoptosis. p-P65 protein expression of TAD cells were induced by ANG II and IKK-β.

CONCLUSION

CTD has the potential to alleviate inflammation, VSMC apoptosis, MMP2/9 levels, and enhance extracellular matrix integrity in TAD by inhibiting the NF-κB signaling pathway.

Polyphenol-rich black currant and cornelian cherry juices ameliorate metabolic syndrome induced by a high-fat high-fructose diet in Wistar rats

Diets high in fat and sugar lead to metabolic syndrome (MetS) and related chronic diseases. We investigated the effects of commercially available, cold-pressed polyphenol-rich black currant (BC) and cornelian cherry (CC) juices on the prevention of MetS in Wistar rats induced by a 10-weeks high-fat high-fructose (HFF) diet. Juice consumption, either BC or CC, with a HFF diet resulted in lower serum triglycerides compared to only the HFF consumption. Both juices also mitigated the effects of HFF on the liver, pancreas, and adipose tissue, by preserving liver and pancreas histomorphology and reducing visceral fat and adipocyte size. Furthermore, supplementation with both juices reduced glucagon and up-regulated insulin expression in the pancreas of the rats on the HFF diet, whereas the BC also showed improved glucose regulation. BC juice also reduced the expression of IL-6 and hepatic inflammation compared to the group only on HFF diet. Both juices, especially BC, could be a convenient solution for the prevention of MetS in humans.

Inflammatory liver diseases and susceptibility to sepsis

Patients with inflammatory liver diseases, particularly alcohol-associated liver disease and metabolic dysfunction-associated fatty liver disease (MAFLD), have higher incidence of infections and mortality rate due to sepsis. The current focus in the development of drugs for MAFLD is the resolution of non-alcoholic steatohepatitis and prevention of progression to cirrhosis. In patients with cirrhosis or alcoholic hepatitis, sepsis is a major cause of death. As the metabolic center and a key immune tissue, liver is the guardian, modifier, and target of sepsis. Septic patients with liver dysfunction have the highest mortality rate compared with other organ dysfunctions. In addition to maintaining metabolic homeostasis, the liver produces and secretes hepatokines and acute phase proteins (APPs) essential in tissue protection, immunomodulation, and coagulation. Inflammatory liver diseases cause profound metabolic disorder and impairment of energy metabolism, liver regeneration, and production/secretion of APPs and hepatokines. Herein, the author reviews the roles of (1) disorders in the metabolism of glucose, fatty acids, ketone bodies, and amino acids as well as the clearance of ammonia and lactate in the pathogenesis of inflammatory liver diseases and sepsis; (2) cytokines/chemokines in inflammatory liver diseases and sepsis; (3) APPs and hepatokines in the protection against tissue injury and infections; and (4) major nuclear receptors/signaling pathways underlying the metabolic disorders and tissue injuries as well as the major drug targets for inflammatory liver diseases and sepsis. Approaches that focus on the liver dysfunction and regeneration will not only treat inflammatory liver diseases but also prevent the development of severe infections and sepsis.

The double roles of T cell-mediated immune response in the progression of MASLD

Metabolic dysfunction-associated steatotic liver disease(MASLD), formerly known as non-alcoholic fatty liver disease(NAFLD), has become a major cause of chronic liver disease and a significant risk factor for hepatocellular carcinoma, which poses a huge burden on global public health and economy. MASLD includes steatotic liver disease, steatohepatitis, and cirrhosis, and the latter two cause great harm to human health and life, even complicated with liver cancer. Immunologic mechanism plays a major role in promoting its development into hepatitis and cirrhosis. Now more and more evidences show that T cells play an important role in the progression of MASLD. In this review, we discuss the double roles of T cells in MASLD from the perspective of T cell response pathways, as well as new evidences regarding the possible application of immunomodulatory therapy in MASH.

The Role of Cytokines in the Pathogenesis and Treatment of Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a major cause of chronic liver disease. This term covers a broad spectrum of liver lesions, from simple steatosis to alcoholic hepatitis and cirrhosis. The pathogenesis of ALD is multifactorial and not fully elucidated due to complex mechanisms related to direct ethanol toxicity with subsequent hepatic and systemic inflammation. The accumulation of pro-inflammatory cytokines and the reduction of anti-inflammatory cytokines promote the development and progression of ALD. To date, there are no targeted therapies to counter the progression of chronic alcohol-related liver disease and prevent acute liver failure. Corticosteroids reduce mortality by acting on the hepatic-systemic inflammation. On the other hand, several studies analyzed the effect of inhibiting pro-inflammatory cytokines and stimulating anti-inflammatory cytokines as potential therapeutic targets in ALD. This narrative review aims to clarify the role of the main cytokines involved in the pathogenesis and treatment of ALD.

Interleukins: Pathogenesis in Non-Alcoholic Fatty Liver Disease

Inflammatory cytokines have been implicated as crucial contributors to the onset and progression of non-alcoholic fatty liver disease (NAFLD). The exact mechanisms by which interleukins (ILs) contribute to NAFLD may vary, and ongoing research is aimed at understanding the specific roles of different ILs in the pathogenesis of this condition. In addition, variations in environmental factors and genetics in each individual can influence the onset and/or progression of NAFLD. The lack of clinical studies related to the potential therapeutic properties of IL-1 inhibitors currently does not allow us to conclude their validity as a therapeutic option, although preclinical studies show promising results. Further studies are needed to elucidate their beneficial properties in NAFLD treatment.

Essential contribution of the JAK/STAT pathway to carcinogenesis, lytic infection of herpesviruses and pathogenesis of COVID‑19 (Review)

The intracellular pathway of Janus kinase/signal transducer and activator of transcription (JAK/STAT) and modification of nucleosome histone marks regulate the expression of proinflammatory mediators, playing an essential role in carcinogenesis, antiviral immunity and the interaction of host proteins with Herpesviral particles. The pathway has also been suggested to play a vital role in the clinical course of the acute infection caused by severe acute respiratory syndrome coronavirus type 2 (SARS‑CoV‑2; known as coronavirus infection‑2019), a novel human coronavirus initially identified in the central Chinese city Wuhan towards the end of 2019, which evolved into a pandemic affecting nearly two million people worldwide. The infection mainly manifests as fever, cough, myalgia and pulmonary involvement, while it also attacks multiple viscera, such as the liver. The pathogenesis is characterized by a cytokine storm, with an overproduction of proinflammatory mediators. Innate and adaptive host immunity against the viral pathogen is exerted by various effectors and is regulated by different signaling pathways notably the JAK/STAT. The elucidation of the underlying mechanism of the regulation of mediating factors expressed in the viral infection would assist diagnosis and antiviral targeting therapy, which will help overcome the infection caused by SARS‑CoV‑2.

What are the common downstream molecular events between alcoholic and nonalcoholic fatty liver?

Liver fat storage, also called hepatic steatosis, is increasingly common and represents a very frequent diagnosis in the medical field. Excess fat is not without consequences. In fact, hepatic steatosis contributes to the progression toward liver fibrosis. There are two main types of fatty liver disease, alcoholic fatty liver disease (AFLD) and nonalcoholic fatty liver disease (NAFLD). Although AFLD and NAFLD are similar in their initial morphological features, both conditions involve the same evolutive forms. Moreover, there are various common mechanisms underlying both diseases, including alcoholic liver disease and NAFLD, which are commonalities. In this Review, the authors explore similar downstream signaling events involved in the onset and progression of the two entities but not completely different entities, predominantly focusing on the gut microbiome. Downstream molecular events, such as the roles of sirtuins, cytokeratins, adipokines and others, should be considered. Finally, to complete the feature, some new tendencies in the therapeutic approach are presented.

CETP-derived Peptide Seq-1, the Key Component of HB-ATV-8 Vaccine Prevents Stress Responses, and Promotes Downregulation of Pro-Fibrotic Genes in Hepatocytes and Stellate Cells

BACKGROUND

The nasal vaccine HB-ATV-8 has emerged as a promising approach for NAFLD (non-alcoholic fatty liver disease) and atherosclerosis prevention. HB-ATV-8 contains peptide seq-1 derived from the carboxy-end of the Cholesteryl Ester Transfer Protein (CETP), shown to reduce liver fibrosis, inflammation, and atherosclerotic plaque formation in animal models. Beyond the fact that this vaccine induces B-cell lymphocytes to code for antibodies against the seq-1 sequence, inhibiting CETP's cholesterol transfer activity, we have hypothesized that beyond the modulation of CETP activity carried out by neutralizing antibodies, the observed molecular effects may also correspond to the direct action of peptide seq-1 on diverse cellular systems and molecular features involved in the development of liver fibrosis.

METHODS

The HepG2 hepatoma-derived cell line was employed to establish an in vitro steatosis model. To obtain a conditioned cell medium to be used with hepatic stellate cell (HSC) cultures, HepG2 cells were exposed to fatty acids or fatty acids plus peptide seq-1, and the culture medium was collected. Gene regulation of COL1A1, ACTA2, TGF-β, and the expression of proteins COL1A1, MMP-2, and TIMP-2 were studied.

AIM

To establish an in vitro steatosis model employing HepG2 cells that mimics molecular processes observed in vivo during the onset of liver fibrosis. To evaluate the effect of peptide Seq-1 on lipid accumulation and pro-fibrotic responses. To study the effect of Seq-1-treated steatotic HepG2 cell supernatants on lipid accumulation, oxidative stress, and pro-fibrotic responses in HSC.

RESULTS AND CONCLUSION

Peptide seq-1-treated HepG2 cells show a downregulation of COLIA1, ACTA2, and TGF-β genes, and a decreased expression of proteins such as COL1A1, MMP-2, and TIMP-2, associated with the remodeling of extracellular matrix components. The same results are observed when HSCs are incubated with peptide Seq-1-treated steatotic HepG2 cell supernatants. The present study consolidates the nasal vaccine HB-ATV-8 as a new prospect in the treatment of NASH directly associated with the development of cardiovascular disease.

Lower creatinine to cystatin C ratio is associated with an increased risk of MASLD: A cross-sectional and prospective study of 368,634 UK Biobank participants

OBJECTIVE

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects many populations, and screening out the high-risk populations at an early stage is a challenge. As a sarcopenia index, the relationship between creatinine to cystatin C ratio (CCR) and MASLD remains unclear. This cross-sectional, prospective study aimed to explore the relationship between CCR and MASLD. Design Firstly, explored the correlation between CCR and MASLD in cross-sectional analyses. Then excluded the population with baseeline diagnosis of MASLD and analyzed the association with baseline CCR levels and the onset of MASLD in the population with available follow-up data. Univariate and multivariate logistic regression analyses were used to calculate odds ratios (ORs) to evaluate the association between CCR levels and MASLD.

PATIENTS AND MEASUREMENTS

This study included 368,634 participants from the UK Biobank for cross-sectional and prospective analyses. The demographic characteristics and laboratory measurements of all participants were obtained from the UK Biobank. MASLD was diagnosed according to the multi-society consensus nomenclature. Hepatic steatosis was defined as FLI  ≥60.

RESULTS

We grouped the study participants according to CCR tertiles. In cross-sectional analyses, participants in CCR tertile 1 had the highest MASLD risk (OR: 1.070, 95% CI: 1.053-1.088, p < .001). And the similar association was observed in the prospective analyses (CCR tertile 1 OR: 1.340, 95% CI: 1.077-1.660, p = .009; CCR tertile 2 OR: 1.217, 95% CI: 1.021-1.450, p = .029, respectively). After stratification by gender, the significant association between CCR and the onset of MASLD was only observed in males (CCR tertile 1 OR: 1.639, 95% CI: 1.160-2.317, p = .005; CCR tertile 2 OR: 1.322, 95% CI: 1.073-1.628, p = .005, respectively).

CONCLUSION

Our results indicated that lower CCR was significantly associated with higher risk of MASLD, based on which predictive models can be developed to screen populations at high risk of developing MASLD.

Association between total body muscle percentage and prevalence of non-alcoholic fatty liver disease in Korean adults findings from an 18-year follow-up: a prospective cohort study

BACKGROUND

This study aimed to elucidate the association between total lean muscle mass and the incidence of non-alcoholic fatty liver disease (NAFLD) in the adult Korean population.

METHODS

Utilizing data derived from the 18-year prospective cohort of the Korean Genome and Epidemiology Study, NAFLD was diagnosed via the hepatic steatosis index with an established cutoff value of 36. Lean muscle mass was assessed via bioelectrical impedance analysis and subsequently divided into tertiles. A generalized mixed model with a logit link was employed for repeated measures data analysis, accounting for potential confounders.

RESULTS

Analysis encompassed 7,794 participants yielding 49,177 measurements. The findings revealed a markedly increased incidence of NAFLD in the lower tertiles of muscle mass, specifically, tertile 1 (odds ratio [OR], 20.65; 95% confidence interval [CI], 9.66-44.11) and tertile 2 (OR, 4.57; 95% CI, 2.11-9.91), in comparison to tertile 3. Age-dependent decreases in the OR were observed within the tertile 1 group, with ORs of 10.12 at age of 40 years and 4.96 at age of 80 years. Moreover, each 1%-point increment in total muscle mass corresponded with an estimated OR of 0.87 (95% CI, 0.82-0.93) for NAFLD resolution.

CONCLUSIONS

The study demonstrates a significant association between total muscle mass and NAFLD prevalence among Korean adults. Given the potential endocrine role of muscle mass in NAFLD pathogenesis, interventions aimed at enhancing muscle mass might serve as an effective public health strategy for mitigating NAFLD prevalence.

Macrophage-derived Osteopontin (SPP1) Protects From Nonalcoholic Steatohepatitis

BACKGROUND & AIMS

Nonalcoholic steatohepatitis (NASH) is characterized by steatosis, lobular inflammation, hepatocyte ballooning degeneration, and fibrosis, all of which increase the risk of progression to end-stage liver disease. Osteopontin (OPN, SPP1) plays an important role in macrophage (MF) biology, but whether MF-derived OPN affects NASH progression is unknown.

METHODS

We analyzed publicly available transcriptomic datasets from patients with NASH, and used mice with conditional overexpression or ablation of Spp1 in myeloid cells and liver MFs, and fed them a high-fat, fructose, and cholesterol diet mimicking the Western diet, to induce NASH.

RESULTS

This study demonstrated that MFs with high expression of SPP1 are enriched in patients and mice with nonalcoholic fatty liver disease (NAFLD), and show metabolic but not pro-inflammatory properties. Conditional knockin of Spp1 in myeloid cells (Spp1KI Mye) or in hepatic macrophages (Spp1KI LvMF) conferred protection, whereas conditional knockout of Spp1 in myeloid cells (Spp1ΔMye) worsened NASH. The protective effect was mediated by induction of arginase-2 (ARG2), which enhanced fatty acid oxidation (FAO) in hepatocytes. Induction of ARG2 stemmed from enhanced production of oncostatin-M (OSM) in MFs from Spp1KI Mye mice. OSM activated STAT3 signaling, which upregulated ARG2. In addition to hepatic effects, Spp1KI Mye also protected through sex-specific extrahepatic mechanisms.

CONCLUSION

MF-derived OPN protects from NASH, by upregulating OSM, which increases ARG2 through STAT3 signaling. Further, the ARG2-mediated increase in FAO reduces steatosis. Therefore, enhancing the OPN-OSM-ARG2 crosstalk between MFs and hepatocytes may be beneficial for patients with NASH.

Combined carvacrol and cilostazol ameliorate ethanol-induced liver fibrosis in rats: Possible role of SIRT1/Nrf2/HO-1 pathway

Carvacrol is a natural phenolic monoterpenoid, and cilostazol is a selective phosphodiesterase-3 inhibitor with antioxidant, anti-inflammatory and antiapoptotic effects. This experiment aimed to explore the hepatoprotective effects of carvacrol and cilostazol alone and in combination against alcoholic liver fibrosis (ALF), and the underlying mechanisms, using silymarin as a reference anti-fibrotic product. ALF was induced by oral administration of ethanol (1 ml/100 g/day) thrice per week. Silymarin (100 mg/kg), carvacrol (70 mg/kg), cilostazol (50 mg/kg), or carvacrol + cilostazol combination were administered daily and concurrently with ethanol for six weeks. Hepatic changes were evaluated by quantifying serum biomarkers of liver injury, hepatic MDA, GSH and NOx as oxidative stress markers, interleukin (IL)-10 as an anti-inflammatory cytokine, 4-hydroxyproline (4-HYP) as a collagen synthesis indicator, transforming growth factor (TGF)-β1 as a profibrogenic cytokine, α-smooth muscle actin (α-SMA) as a marker of hepatic stellate cells (HSCs) activation, histopathological (necroinflammation and fibrosis) scores and hepatic sirtuin-1 (SIRT1), nuclear factor-erythroid 2-related factor 2 (Nrf2), and hemeoxygenase-1 (HO-1) mRNA levels. Our results showed that carvacrol, cilostazol, and their combination significantly ameliorated ethanol-induced hepatic fibrosis manifested as improving hepatic functions and histopathological features, attenuating α-SMA immunostaining, reducing TGF-β1 and 4-HYP levels, suppressing oxidativeinjury and elevating IL-10 contents. Such effects were accompanied by upregulating SIRT1, Nrf2 and HO-1 genes. This work disclosed for the first time the hepatoprotective effect of carvacrol against ALF and, to a greater extent, with carvacrol + cilostazol combination that could be partially accredited to SIRT1/Nrf2/HO-1 pathway with consequent antioxidant, anti-inflammatory, and anti-fibrotic features.

Inhibitory effect of non-alcoholic steatohepatitis on colon cancer liver metastasis

BACKGROUND

The incidence of non-alcoholic steatohepatitis (NASH) is dramatically increasing, but the effect of NASH on colon cancer liver metastasis (CLM) is controversial. The aim of this study was to investigate the impact and mechanism of action of NASH on CLM using a western diet (WD)-fed mouse model.

METHODS

Six-week-old male C57BL/6 J mice were used. They were divided into the WD group and control group with normal diet. MC38 colon cancer cells were injected into the spleen at 2, 6, 8 and 16 weeks, and mice were killed at 2 weeks after injection to evaluate hepatic steatosis, fibrosis, metastasis and mRNA/protein expression in the liver.

RESULTS

Only mice fed a WD for 16 weeks showed hepatic fibrosis. These mice showed significantly higher alanine aminotransferase and total cholesterol levels compared with the control group (p < 0.05). The WD group showed significantly lower tumor number and smaller tumor diameter (p < 0.05). In the WD group, expression of SAA1, IL6, STAT3 and MMP9 mRNA in the liver was significantly lower than in the control group (p < 0.05). Serum amyloid A1 protein expression was also lower in the WD group.

CONCLUSIONS

The WD-fed NASH mouse model showed an inhibitory effect on CLM. Suppressed interleukin-6/signal transducer and activator of transcription 3 signaling and serum amyloid A/matrix metalloproteinase 9 expression may affect this phenomenon.

Associations of muscle mass and grip strength with severe NAFLD: A prospective study of 333,295 UK Biobank participants

BACKGROUND & AIMS

Cross-sectional studies have reported that lower muscle mass and strength are risk factors for non-alcoholic fatty liver disease (NAFLD). However, the evidence from prospective studies is limited. This study examined both the strength and pattern of the associations between these 2 physical capability markers and severe NAFLD using data from the UK Biobank study.

METHODS

A total of 333,295 participants were included in this prospective study. Grip strength was measured using a Jamar J00105 hydraulic hand dynamometer, and the Janssen equation was used to estimate skeletal muscle mass by bioelectrical impedance. Muscle mass was adjusted for body weight and all exposures were sex-standardised. Associations of muscle mass and strength with severe NAFLD (defined as hospital admission or death) were first investigated by tertile of each exposure using Cox proportional hazard models. Non-linear associations were investigated using penalised cubic splines fitted in the Cox proportional hazard models.

RESULTS

After a median follow-up of 10 years (IQR 9.3 to 10.7 years), 3,311 individuals had severe NAFLD (3,277 hospitalisations and 34 deaths). Compared with the lowest tertile of muscle mass, the risk of severe NAFLD was lower in the middle (hazard ratio 0.76; 95% CI 0.70-0.83) and the highest tertile (hazard ratio 0.46; 95% CI 0.40-0.52). Tertiles of grip strength showed a similar pattern. Non-linearity was only identified for muscle mass (p <0.001). Being on the lower tertile of grip strength and muscle mass accounted for 17.7% and 33.1% of severe NAFLD cases, respectively.

CONCLUSIONS

Lower muscle mass and grip strength were associated with higher risk of developing severe NAFLD. Interventions to improve physical capability may be protective, but this needs to be investigated in appropriately designed trials.

LAY SUMMARY

Lower muscle mass - both quantity and quality - were associated with a higher risk of severe non-alcoholic fatty liver disease. Therefore, improving muscle mass might be a protective factor against this increasing public health problem.

MicroRNA-29b ameliorates hepatic inflammation via suppression of STAT3 in alcohol-associated liver disease

Alcohol-associated liver disease (ALD) is induced by chronic excessive alcohol consumption resulting in the clinical manifestations of steatosis, inflammation, and cirrhosis. MicroRNA-29b (miR-29b) is mainly expressed in hepatic nonparenchymal cells, and its expression level varies in different diseases. In this study, we aimed to determine the role of miR-29b in a mouse model of alcohol-associated liver disease. Wild-type (WT) and miR-29b knockout (miR-29b^-/-) mice were fed a Lieber-DeCarli liquid diet containing 5% alcohol for 10 days, followed by gavage of a single dose of ethanol (5 g/kg body weight). Histology, immunoblotting, and biochemical analyses were then conducted for comparison. miR-29b expression was decreased in the livers of chronic-plus-binge ethanol-fed mice. Further analysis revealed that alcohol exposure exacerbated hepatic injury by significantly increasing serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, with decreased survival rates for miR-29b^-/- mice. Results from the luciferase assay indicated that miR-29b negatively regulated the signal transducer and activator of transcription 3 (STAT3). Depletion of miR-29b led to an increase in STAT3 and more noticeable inflammation in the liver, whereas overexpression of miR-29b downregulated STAT3 and proinflammatory cytokine expression in primary mouse peritoneal macrophages. Taken together, these results demonstrate a novel association between miR-29b and ALD. miR-29b plays a hepatoprotective role in alcohol-induced inflammation and liver injury by targeting STAT3.

Adipose tissue regulatory T cells: differentiation and function

Rising obesity levels, worldwide, are resulting in substantial increases in cardiovascular disease, diabetes, kidney disease, musculoskeletal disorders, and certain cancers, and obesity-associated illnesses are estimated to cause ∼4 million deaths worldwide per year. A common theme in this disease epidemic is the chronic systemic inflammation that accompanies obesity. CD4+ Foxp3+ regulatory T cells residing in visceral adipose tissues (VAT Tregs) are a unique immune cell population that play essential functions in restricting obesity-associated systemic inflammation through regulation of adipose tissue homeostasis. The distinct transcriptional program that defines VAT Tregs has been described, but directly linking VAT Treg differentiation and function to improving insulin sensitivity has proven more complex. Here we review new findings which have clarified how VAT Tregs differentiate, and how distinct VAT Treg subsets regulate VAT homeostasis, energy expenditure, and insulin sensitivity.

Interleukins in adipose tissue: Keeping the balance

The role of the immune system is to defend the host and preserve the functionality in response to stress. This function is not limited to infection or injury as it also plays a role in the response to overnutrition. Indeed, low-grade chronic activation of the immune system associated with overnutrition may be deleterious, contributing importantly to diabetes and long-term complications, such as cardiovascular disorders. Increasing evidence shows that adipose tissue participates in the obesity-related inflammatory response and that interleukins are one of the key players, either as a pro-inflammatory response to the metabolic dysregulation or to restore homeostasis. The crosstalk between adipocytes and immune cells through some important interleukins and their role in metabolic disruption is the topic of this review.

TTC39B destabilizes retinoblastoma protein promoting hepatic lipogenesis in a sex-specific fashion

BACKGROUND & AIMS

Molecular mechanisms underlying the different susceptibility of men and women to non-alcoholic fatty liver disease (NAFLD) are poorly understood. The TTC39B locus encodes a scaffolding protein, associates with gynecological disorders and its deletion protects mice from diet-induced steatohepatitis. This study aimed to elucidate the molecular mechanisms linking TTC39B (T39) to the expression of lipogenic genes and to explore sex-specific effects.

METHODS

Co-expression in HEK293A cells validated the novel T39/pRb interaction predicted by a protein-protein interaction algorithm. T39 was knocked down using an antisense oligonucleotide (ASO) in mice with dietary NAFLD and a genetic deficiency of pRb or its downstream effector E2F1, as well as in primary human hepatocytes.

RESULTS

T39 interacts with pRb via its C-terminal TPR domain and promotes its proteasomal degradation. In female mice, T39 deficiency reduces the mRNA of lipogenic genes, especially Pnpla3, in a pRb- and E2F1-dependent manner. In contrast, in male mice, T39 deficiency results in a much smaller reduction in lipogenic gene expression that is independent of pRb/E2F1. T39 also interacts with VAPB via an N-terminal FFAT motif and stabilizes the interaction of VAPB with SCAP. Ovariectomy abolishes the effect of T39 knockdown on the hepatic pRb/E2F1/Pnpla3 axis. In both sexes T39 knockdown reduces SCAP independently of pRb. In primary human hepatocytes, T39 knockdown reduces expression of PNPLA3 and other lipogenic genes in women but not men.

CONCLUSIONS

We have uncovered a conserved sexual dimorphism in the regulation of hepatic lipogenic genes, with effects of T39 mediated through pRb/E2F1 in females and VAPB/SCAP in both sexes. T39 inhibition could be a novel strategy to downregulate PNPLA3 and treat NAFLD in women.

LAY SUMMARY

In females, the protein TTC39B degrades a tumor suppressor in the liver to promote the synthesis of new fat and the expression of a major genetic risk factor for non-alcoholic fatty liver disease. TTC39B is a potential therapeutic target for non-alcoholic fatty liver disease, especially in women.

The Association of Sarcopenia and Visceral Obesity with Lean Nonalcoholic Fatty Liver Disease in Chinese Patients with Type 2 Diabetes Mellitus

BACKGROUND

Few studies have specifically observed the relationship of sarcopenia, visceral obesity, or their joint effects with lean NAFLD in patients with diabetes. We aimed to investigate the associations of lean NAFLD with sarcopenia, visceral obesity, and sarcopenic visceral obesity (SV) in Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

Altogether, 1,112 T2DM patients with BMI <25 kg/m² were enrolled, and 33.18% of them were diagnosed with lean NAFLD by abdominal ultrasonography. Body composition markers were measured by bioelectrical impedance (BIA). Skeletal muscle mass index (SMI) was calculated as appendicular skeletal muscle mass (ASM) divided by weight, and sarcopenia was defined as SMI < 1 standard deviation (SD) below the sex-specific average for a young reference population. Visceral obesity was defined as visceral fat area (VFA) ≥ 100 cm². Participants were categorized into one of the four body composition groups: nonsarcopenia/nonvisceral obesity (NN), nonsarcopenia/visceral obesity (NV), sarcopenia/nonvisceral obesity (SN), and SV.

RESULTS

Compared to those in the NN group, patients in the NV and SN groups had a higher risk of lean NAFLD after full adjustments (NV: OR = 1.74; 95% CI: 1.09, 2.78; SN: OR =2.07; 95% CI: 1.23, 3.46). Of note, patients in the SV group had the highest odds of lean NAFLD (OR = 3.29; 95% CI: 2.10, 5.17). There were no significant interaction effects between sarcopenia and metabolic risk factors on prevalent lean NAFLD.

CONCLUSIONS

The current study demonstrated that SV was more closely associated with higher prevalent lean NAFLD than sarcopenia or visceral obesity alone in Chinese patients with T2DM. Besides, the harmful effect of sarcopenia on lean NAFLD was not influenced by visceral obesity or other metabolic risk factors. We hypothesize that increasing skeletal muscle mass more than just reducing visceral fat might be more optimal for the prevention and management of lean NAFLD, which needs further investigation in future studies.

STAT3: A key regulator in liver fibrosis

Janus protein tyrosine kinase (JAK) has the ability to activate signal transducer and activator of transcription (STAT). STAT3 is a valued member of the JAK/STAT signaling pathway. In recent years, several studies have documented that STAT3 is closely related to the occurrence and development of liver fibrosis caused by various factors. Activation of STAT3 can play anti- or pro-inflammatory roles in the pathogenesis of liver fibrosis. This article reviewed the recent studies on STAT3 in the development of various liver fibrosis to find a more effective method to relieve and cure liver diseases, such as hepatitis B virus (HBV), non-alcoholic fatty liver disease (NAFLD), schistosomiasis, and chemical liver injury.

Longitudinal Associations Between Hand Grip Strength and Non-Alcoholic Fatty Liver Disease in Adults: A Prospective Cohort Study

Purpose: This study aimed to determine the longitudinal association between hand grip strength (HGS) and the development of non-alcoholic fatty liver disease (NAFLD) in adults. Design: A cohort study. Methods: This study was conducted in a general Chinese population (n = 14,154) from 2013-2018. NAFLD was diagnosed by liver ultrasonography during evaluating alcohol consumption. The associations between the HGS and NAFLD were assessed using a multivariable Cox proportional hazards regression model. Results: During the study period with a mean follow-up duration of 3.20 years, 2,452 participants developed NAFLD. The risk of NAFLD decreased progressively with increasing HGS in both men and women (P for trend <0.0001). The multivariate-adjusted hazard ratios (95% CI) for NAFLD incidence across the quartiles of HGS were 1 (reference), 0.90 (0.79, 1.02), 0.69 (0.60, 0.79), and 0.44 (0.37, 0.52) for men and 1 (reference), 0.82 (0.69, 0.96), 0.54 (0.45, 0.66), and 0.41 (0.33, 0.52) for women, respectively. The interaction terms for body mass index (BMI)-HGS and waist-HGS were significant in men and women (all P < 0.0001). The participants with normal BMIs and waist circumferences had the lowest hazard ratios on the subgroup analyses. The sensitivity analysis that defined NAFLD using the hepatic steatosis and fatty liver indices revealed results that were similar to the main analyses. Conclusion: The present study indicates that the HGS is inversely associated with the incidence of NAFLD.

Untargeted serum metabolites profiling in high-fat diet mice supplemented with enhanced palm tocotrienol-rich fraction using UHPLC-MS

Excessive high fat dietary intake promotes risk of developing non-alcoholic fatty liver disease (NAFLD) and predisposed with oxidative stress. Palm based tocotrienol-rich fraction (TRF) has been reported able to ameliorate oxidative stress but exhibited poor bioavailability. Thus, we investigated whether an enhanced formulation of TRF in combination with palm kernel oil (medium-chain triglycerides) (ETRF) could ameliorate the effect of high-fat diet (HFD) on leptin-deficient male mice. All the animals were divided into HFD only (HFD group), HFD supplemented with ETRF (ETRF group) and HFD supplemented with TRF (TRF group) and HFD supplemented with PKO (PKO group). After 6 weeks, sera were collected for untargeted metabolite profiling using UHPLC-Orbitrap MS. Univariate analysis unveiled alternation in metabolites for bile acids, amino acids, fatty acids, sphingolipids, and alkaloids. Bile acids, lysine, arachidonic acid, and sphingolipids were downregulated while xanthine and hypoxanthine were upregulated in TRF and ETRF group. The regulation of these metabolites suggests that ETRF may promote better fatty acid oxidation, reduce oxidative stress and pro-inflammatory metabolites and acts as anti-inflammatory in fatty liver compared to TRF. Metabolites regulated by ETRF also provide insight of its role in fatty liver. However, further investigation is warranted to identify the mechanisms involved.

Alternative activation of macrophages by prostacyclin synthase ameliorates alcohol induced liver injury

Alcoholic liver disease (ALD) is a major cause of chronic liver disease worldwide. Macrophages exhibit different functional states and are classified as classically activated (M1) and alternatively activated (M2) macrophages. However, the mechanisms that govern M1/M2 polarization in chronic ALD remain to be elucidated. Prostacyclin (PGI2) synthase (PTGIS) is an enzyme of the prostaglandin pathway which catalyzes the conversion of Prostaglandin H2 (PGH2) to PGI2. PTGIS has anti-inflammatory properties. However, the function of PTGIS in ALD has not yet been determined. In this study, we demonstrated that PTGIS was downregulated in ALD and forced PTGIS expression in vivo using recombinant adeno-associated viral vector-packed PTGIS overexpression plasmid, which alleviated the inflammatory response and suppressed the macrophage M1 phenotype in mice. Loss- and gain-of function-experiments demonstrated that forced PTGIS expression inhibited the macrophage switch to the M1 phenotype and promoted M2 polarization. Furthermore, we identified the genes regulated by PTGIS through RNA-sequencing (RNA-seq) analysis. Gene ontology and KEGG pathway analyses showed that PTGIS regulates many genes involved in the immune response and is enriched in the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signal transduction pathway, which plays an important role in regulating macrophage polarization. The proteins interacting with JAKs were predicted using the STRING database. The overlap between the RNA-seq and the STRING database was interleukin-6; this indicated that it was involved in macrophage polarization regulated by JAK/STAT signaling. We further explored the microRNAs that could regulate the expression of PTGIS through TargetScan. The results of luciferase assay illustrated that the expression of PTGIS was regulated by miR-140-3p.1. These results imply that PTGIS plays a pivotal role in ALD, partly by influencing macrophage polarization.

TGR5 Expression Is Associated with Changes in the Heart and Urinary Bladder of Rats with Metabolic Syndrome

Adipose-derived cytokines may contribute to the inflammation that occurs in metabolic syndrome (MetS). The Takeda G protein-coupled receptor (TGR5) regulates energy expenditure and affects the production of pro-inflammatory biomarkers in metabolic diseases. Etanercept, which acts as a tumor necrosis factor (TNF)-α antagonist, can also block the inflammatory response. Therefore, the interaction between TNF-α and TGR5 expression was investigated in rats with high-fat diet (HFD)-induced obesity. Heart tissues isolated from the HFD-induced MetS rats were analyzed. Changes in TGR5 expression were investigated with lithocholic acid (LCA) as the agonist. Betulinic acid (BA) was used to activate TGR5 in urinary bladders. LCA was more effective in the heart tissues of HFD-fed rats, although etanercept alleviated the function of LCA. STAT3 activation and higher TGR5 expression were observed in the heart tissues collected from HFD-fed rats. Thus, cardiac TGR5 expression is promoted by HFD through STAT3 activation in rats. Moreover, the urinary bladders of female rats fed a HFD showed a low response, which was reversed by etanercept. Relaxation by BA in the bladders was more marked in HFD-fed rats. The high TGR5 expression in HFD-fed rats was characterized using a mRNA assay, and the increased cAMP levels were found to be stimulated by BA in the isolated bladders. Therefore, TGR5 expression increases with a HFD in both the hearts and urinary bladders. Collectively, cytokine-medicated TGR5 activation was observed in the hearts and urinary bladders of rats.

Myeloid-Cell-Specific IL-6 Signaling Promotes MicroRNA-223-Enriched Exosome Production to Attenuate NAFLD-Associated Fibrosis

BACKGROUND ANDS AIMS

NAFLD is associated with elevation of many cytokines, particularly IL-6; however, the role of IL-6 in NAFLD remains obscure. The aim of this study was to examine how myeloid-specific IL-6 signaling affects NAFLD by the regulation of antifibrotic microRNA-223 (miR-223) in myeloid cells.

APPROACH AND RESULTS

Patients with NAFLD or NASH and healthy controls were recruited, and serum IL-6 and soluble IL-6 receptor α (sIL-6Rα) were measured. Compared to controls, serum IL-6 and sIL-6Rα levels were elevated in NAFLD/NASH patients. IL-6 levels correlated positively with the number of circulating leukocytes and monocytes. The role of IL-6 in NAFLD was investigated in Il6 knockout (KO) and Il6 receptor A (Il6ra) conditional KO mice after high-fat diet (HFD) feeding. HFD-fed Il6 KO mice had worse liver injury and fibrosis, but less inflammation, compared to wild-type mice. Hepatocyte-specific Il6ra KO mice had more steatosis and liver injury, whereas myeloid-specific Il6ra KO mice had a lower number of hepatic infiltrating macrophages (IMs) and neutrophils with increased cell death of these cells, but greater liver fibrosis (LF), than WT mice. Mechanistically, the increased LF in HFD-fed, myeloid-specific Il6ra KO mice was attributable to the reduction of antifibrotic miR-223 and subsequent up-regulation of the miR-223 target gene, transcriptional activator with PDZ-binding motif (TAZ), a well-known factor to promote NASH fibrosis. In vitro, IL-6 treatment up-regulated exosome biogenesis-related genes and subsequently promoted macrophages to release miR-223-enriched exosomes that were able to reduce profibrotic TAZ expression in hepatocytes by exosomal transfer. Finally, serum IL-6 and miR-223 levels were elevated and correlated with each other in NAFLD patients.

CONCLUSIONS

Myeloid-specific IL-6 signaling inhibits LF through exosomal transfer of antifibrotic miR-223 into hepatocytes, providing therapeutic targets for NAFLD therapy.

The two facets of gp130 signalling in liver tumorigenesis

The liver is a vital organ with multiple functions and a large regenerative capacity. Tumours of the liver are the second most frequently cause of cancer-related death and develop in chronically inflamed livers. IL-6-type cytokines are mediators of inflammation and almost all members signal via the receptor subunit gp130 and the downstream signalling molecule STAT3. We here summarize current knowledge on how gp130 signalling and STAT3 in tumour cells and cells of the tumour micro-environment drives hepatic tumorigenesis. We furthermore discuss very recent findings describing also anti-tumorigenic roles of gp130/STAT3 and important considerations for therapeutic interventions.

Interleukin-10 Attenuates Liver Fibrosis Exacerbated by Thermoneutrality

Background: Crosstalk between brown adipose tissue (BAT) and the liver is receiving increasing attention. This study investigated the effect of BAT dysfunction by thermoneutral (TN) housing on liver fibrosis in mice and examined the effect of secreted factors from brown adipocytes on the activation of hepatic stellate cells (HSCs).

Methods: The carbon tetrachloride (CCl₄)-induced liver fibrosis mouse model was used to evaluate fibrotic changes in the livers of mice housed under standard and TN conditions. The effect of BAT on the activation of HSCs was examined using cultured cells treated with conditioned media from brown adipocytes.

Results: Under TN conditions, mice with CCl₄-induced liver fibrosis exhibited increased liver injury, collagen deposition, and alpha smooth muscle actin (α-SMA) expression in the liver compared with mice maintained at room temperature. The numbers of liver-infiltrating immune cells and T cells producing IL-17A and IFN-γ were also significantly increased in the livers of mice housed under TN conditions. Treatment of HSCs with conditioned media from brown adipocytes markedly attenuated HSC activation, as shown by down-regulated α-SMA expression at day 4, day 7 and day 10 of culture. At thermoneutrality, with CCl₄ administration, IL-10-deficient mice exhibited more severe liver fibrosis than wild-type mice. Interestingly, conditioned media from IL-10-deficient brown adipocytes could up-regulate the expression of α-SMA and induce HSCs activation.

Conclusions: BAT inactivation by thermoneutrality contributes to the activation of pro-inflammatory and pro-fibrotic pathways in mice with CCl₄-induced liver fibrosis. Normal brown adipocytes secreted factors that impair the activation of HSCs, while this protective effect was lost in IL-10-deficient brown adipocytes. Thus, the BAT–liver axis may serve as a potential therapeutic target for liver fibrosis, and IL-10 may be a key factor regulating the activation of HSCs by BAT.

Mesencephalic astrocyte-derived neurotrophic factor alleviates alcohol induced hepatic steatosis via activating Stat3-mediated autophagy

Alcoholic fatty liver disease (AFLD) is induced by alcohol consumption and may progress to more severe liver diseases such as alcoholic steatohepatitis, fibrosis and cirrhosis, and even hepatocellular carcinoma. Mesencephalic astrocyte-derived neurotrophic factor (MANF) participates in maintaining lipid homeostasis. However, the role of MANF in the pathogenesis of AFLD remains unclear. We established an AFLD mouse model following the US National Institute on Alcohol Abuse and Alcoholism procedure. Both mRNA and protein levels of MANF were significantly increased in the chronic binge alcohol feeding model. Liver-specific knockout of MANF aggravated hepatic lipid accumulation. Similarly, liver-specific overexpression of MANF alleviated AFLD in mouse livers. MANF affected hepatic lipid metabolism by modulating autophagy. The levels of LC3-II and Atg5-Atg12 were decreased in mouse livers with MANF liver-specific knockout and increased with MANF liver-specific overexpression. Furthermore, MANF changed the phosphorylation of Stat3 and its nuclear localization. MANF may have a protective role in the development of AFLD.

A review on molecular mechanism of alcoholic liver disease

Excessive alcohol consumption leads to damage to the organs of the body. More importantly, the liver is majorly affected organ upon alcohol consumption for most of the people; it causes inflammation and affects various pathways involved in metabolism. If the person is with high response of inflammatory in conduct with alcohol leads to the liver damage, which involves the creating effects with major cycle leads to homeostasis. In this review, we summarize the molecular mechanisms of alcoholic liver disease, such as the important role of genes, risk factors, pathogenicity, and role of micro RNA, the role of inflammation in the liver, and alcoholic fibrosis in the liver. There is increased oxidative stress, change in the biochemical alterations, and reduction in the antioxidant enzymes. These changes in the mechanism lead to liver injury. Hepatocyte nuclear factor-4 is the major transcriptional factor for the regulation of some genes involved in the lipid metabolism and oxidation process; with the help of the agonist, we can attenuate the level of the gene in the site of hepatic tissues, which will prevent the homeostatic condition. This review shows a clear view of the various pathways involved in alcohol consumption, which helps in the prevention of ALD using an agonist.

Redox treatment ameliorates diabetes mellitus-induced skin flap necrosis via inhibiting apoptosis and promoting neoangiogenesis

Intractable wound healing is the habitual problem of diabetes mellitus. High blood glucose limits wound healing by interrupting inflammatory responses and inhibiting neoangiogenesis. Oxidative stress is commonly thought to be a major pathogenic cause of diabetic complications. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one, EDV) is a free radical scavenger which suppress oxidative stress. This study investigates whether EDV can reduce oxidative stress in wound healing HaCaT/human dermal fibroblasts cells (HDFs) in vitro and in vivo animal model. Cell viability and wound healing assays, FACS flow cytometry, and Hoechst 33342 staining were performed to confirm apoptosis and cytotoxicity in H2O2 and EDV-treated HaCaT and HDFs. A streptozotocin-induced hyperglycemic animal model was made in adult C57BL6 mice. Full-thickness skin flap was made on dorsomedial back and re-sutured to evaluate the wound healing process. EDV was delivered slowly in the skin flap with degradable fibrin glue. The flap was monitored and analyzed on postoperative days 1, 3, and 5. CD31/DAPI staining was done to detect newly formed blood vessels. The expression levels of NF-κB, bcl-2, NOX3, and STAT3 proteins in C57BL6 mouse tissues were also examined. The wound healing process in hyper- and normoglycemic mice showed a difference in protein expression, especially in oxidative stress management and angiogenesis. Exogenous H2O2 reduced cell viability in a proportion to the concentration via apoptosis. EDV protected HaCaT cells and HDFs from H2O2 induced reactive oxygen species cell damage and apoptosis. In the mouse model, EDV with fibrin resulted in less necrotic areas and increased angiogenesis on postoperative day 5, compared to sham-treated mice. Our results indicate that EDV could protect H2O2-induced cellular injury via inhibiting early apoptosis and inflammation and also increasing angiogenesis. EDV might be valuable in the treatment of diabetic wounds that oxidative stress has been implicated.

Development and validation of a noninvasive clinical scoring system to predict significant fibrosis in patients with nonalcoholic fatty liver disease

BACKGROUND

The aims of this study were to identify risk factors for significant fibrosis (SF) by assessing physical and laboratory parameters and develop and validate a clinical score and nomogram for the prediction of SF in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

This retrospective study included 225 patients with histologically confirmed NAFLD who were divided into two cohorts using 10-fold cross validation for model training and validation. The clinical score and nomogram were used to predict the NAFLD outcome.

RESULTS

The model for predicting SF (stage ≥ 2) including the free T4/free T3 ratio, low-density lipoprotein cholesterol, homeostatic model assessment for insulin resistance (HOMA-IR), percentage of appendicular skeletal muscle mass and aspartate aminotransferase (AST) level in the training and validation cohorts yielded an area under the receiver operator characteristic curve (AUROC) of 0.79 and 0.78, respectively. The AUROC of the combined clinical score for the prediction of SF was 0.82 (95% CI, 0.75-0.89) at a cutoff value of 3 points, with a sensitivity (SE) of 77.19%, specificity (SP) of 82.88%, positive predictive value (PPV) of 63.77%, and negative predictive value (NPV) of 90.30%. The nomogram had good performance in quantitatively predicting the risk probability of SF.

CONCLUSION

Our study showed that a noninvasive clinical scoring system using easily available physical and laboratory variables can identify patients with NAFLD with or without SF with a high degree of accuracy. Application of this system may decrease the need for staging liver biopsy specimens and allow early identification and intervention in these high-risk patients.

Deletion of the nuclear receptor RORα in macrophages does not modify the development of obesity, insulin resistance and NASH

Retinoic acid receptor-related orphan receptor-alpha (RORα) is a transcription factor from the nuclear receptor family expressed by immune cells and involved in the development of obesity, insulin resistance (IR) and non-alcoholic steatohepatitis (NASH). It was recently reported that mice deficient for RORα in macrophages develop more severe NASH upon high fat diet (HFD) feeding due to altered Kupffer cell function. To better understand the role of RORα in obesity and IR, we independently generated a macrophage RORα-deficient mouse line. We report that RORα deletion in macrophages does not impact on HFD-induced obesity and IR. Surprisingly, we did not confirm an effect on NASH development upon HFD feeding nor in the more severe and obesity-independent choline-deficient, L-amino acid-defined diet model. Our results therefore show that RORα deletion in macrophages does not alter the development of obesity and IR and question its role in NASH.

Targeted treatment of alcoholic liver disease based on inflammatory signalling pathways

Targeted therapy is an emerging treatment strategy for alcoholic liver disease (ALD). Inflammation plays an important role in the occurrence and development of ALD, and is a key choice for its targeted treatment, and anti-inflammatory treatment has been considered beneficial for liver disease. Surprisingly, immune checkpoint inhibitors have become important therapeutic agents for hepatocellular carcinoma (HCC). Moreover, studies have shown that the combination of inflammatory molecule inhibitors and immune checkpoint inhibitors can exert better effects than either alone in mouse models of HCC. This review discusses the mechanism of hepatic ethanol metabolism and the conditions under which inflammation occurs. In addition, we focus on the potential molecular targets in inflammatory signalling pathways and summarize the potential targeted inhibitors and immune checkpoint inhibitors, providing a theoretical basis for the targeted treatment of ALD and the development of new combination therapy strategies for HCC.

Immunopathobiology and therapeutic targets related to cytokines in liver diseases

Chronic liver injury with any etiology can progress to fibrosis and the end-stage diseases cirrhosis and hepatocellular carcinoma. The progression of liver disease is controlled by a variety of factors, including liver injury, inflammatory cells, inflammatory mediators, cytokines, and the gut microbiome. In the current review, we discuss recent data on a large number of cytokines that play important roles in regulating liver injury, inflammation, fibrosis, and regeneration, with a focus on interferons and T helper (Th) 1, Th2, Th9, Th17, interleukin (IL)-1 family, IL-6 family, and IL-20 family cytokines. Hepatocytes can also produce certain cytokines (such as IL-7, IL-11, and IL-33), and the functions of these cytokines in the liver are briefly summarized. Several cytokines have great therapeutic potential, and some are currently being tested as therapeutic targets in clinical trials for the treatment of liver diseases, which are also described.

Relative Skeletal Muscle Mass Is an Important Factor in Non-Alcoholic Fatty Liver Disease in Non-Obese Children and Adolescents

Recently, sarcopenia was identified as a risk factor for non-alcoholic fatty liver disease (NAFLD) in adults. We here investigated the association between skeletal muscle mass (SMM) and NAFLD in non-obese children and adolescents. A retrospective medical chart review was performed for individuals aged 9–15 years diagnosed with NAFLD. Healthy volunteers aged 9–15 years were recruited as controls. Participants were subject to laboratory tests, abdominal sonography, and multi-frequency bioelectrical impedance analysis. SMM data were calculated as the skeletal muscle-to-body fat ratio (MFR), and the diagnosis of fatty liver was established by abdominal sonography. The control and NAFLD groups included 73 and 53 individuals, respectively. No significant difference was observed in gender and body mass index (BMI) distribution between the groups. Mean MFR was significantly lower in individuals with NAFLD than in those without (0.83 vs. 1.04, p = 0.005). After adjusting for age, sex, BMI, and serum glucose, the risk of having NAFLD was significantly associated with a decreased MFR (p = 0.016). NAFLD is significantly associated with relatively low SMM in non-obese children and adolescents. Increasing SMM, such as weight training, can be suggested as one of the treatment strategies in pediatric NAFLD without obesity.

WITHDRAWN: Higher appendicular skeletal muscle mass percentage is an independent protective factor for non-alcoholic steatohepatitis and significant fibrosis in male with NAFLD

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Biology and therapeutic potential of interleukin-10

The authors review the molecular mechanisms regulating IL-10 production and response and describe classic and novel functions of IL-10 in immune and non-immune cells. They further discuss the therapeutic potential of IL-10 in different diseases and the outstanding questions underlying an effective application of IL-10 in clinical settings.

The cytokine IL-10 is a key anti-inflammatory mediator ensuring protection of a host from over-exuberant responses to pathogens and microbiota, while playing important roles in other settings as sterile wound healing, autoimmunity, cancer, and homeostasis. Here we discuss our current understanding of the regulation of IL-10 production and of the molecular pathways associated with IL-10 responses. In addition to IL-10’s classic inhibitory effects on myeloid cells, we also describe the nonclassic roles attributed to this pleiotropic cytokine, including how IL-10 regulates basic processes of neural and adipose cells and how it promotes CD8 T cell activation, as well as epithelial repair. We further discuss its therapeutic potential in the context of different diseases and the outstanding questions that may help develop an effective application of IL-10 in diverse clinical settings.

Hypoxia-Inducible Factor-2α Reprograms Liver Macrophages to Protect Against Acute Liver Injury Through the Production of Interleukin-6

BACKGROUND AND AIMS

Acetaminophen (APAP) overdose represents the most frequent cause of acute liver failure, resulting in death or liver transplantation in more than one third of patients in the United States. The effectiveness of the only antidote, N-acetylcysteine, declines rapidly after APAP ingestion, long before patients are admitted to the clinic with symptoms of severe liver injury. The direct hepatotoxicity of APAP triggers a cascade of innate immune responses that may exacerbate or limit the progression of tissue damage. A better understanding of this complex mechanism will help uncover targets for therapeutic interventions.

APPROACH AND RESULTS

We observed that APAP challenge caused stabilization of hypoxia-inducible factors (HIFs) in the liver and hepatic macrophages (MΦs), particularly HIF-2α. Genetic deletion of the HIF-2α gene in myeloid cells (HIF-2α^mye/- ) markedly exacerbated APAP-induced liver injury (AILI) without affecting APAP bioactivation and detoxification. In contrast, hepatic and serum levels of the hepatoprotective cytokine interleukin 6 (IL-6), its downstream signal transducer and transcription factor 3 activation in hepatocytes, as well as hepatic MΦ IL-6 expression were markedly reduced in HIF-2α^mye/- mice compared to wild-type mice post-APAP challenge. In vitro experiments revealed that hypoxia induced IL-6 production in hepatic MΦs and that such induction was abolished in HIF-2α-deleted hepatic MΦs. Restoration of IL-6 by administration of exogenous IL-6 ameliorated AILI in HIF-2α^mye/- mice. Finally, IL-6-mediated hepatoprotection against AILI was abolished in hepatocyte-specific IL-6 receptor knockout mice.

CONCLUSIONS

The data demonstrate that APAP treatment leads to HIF-2α stabilization in hepatic MΦs and that HIF-2α subsequently reprograms hepatic MΦs to produce the hepatoprotective cytokine IL-6, thereby ameliorating AILI.

Repeated stretch-shortening contraction of the triceps surae attenuates muscle atrophy and liver dysfunction in a rat model of inflammation

NEW FINDINGS

What is the central question of this study? Is stretch-shortening contraction effective to attenuate skeletal muscle atrophy and hepatic dysfunction in a rat model of peptidoglycan-polysaccharide (PG-PS)-induced inflammation (PG-PS rat)? What are the main findings and their importance? Stretch-shortening contraction attenuates skeletal muscle atrophy in the trained leg and increases circulating interleukin-10 in PG-PS rats. Stretch-shortening contraction also ameliorates liver dysfunction in PG-PS rats, possibly via increased blood interleukin-10. These findings are important because they suggest that stretch-shortening contraction is effective to maintain liver function in addition to exercised skeletal muscle mass.

ABSTRACT

Stretch-shortening contraction (SSC) is an effective modality to improve skeletal muscle mass. However, the beneficial effects of SSC in the presence of chronic inflammation remain unclear. Here, we imposed five SSC sessions unilaterally on the triceps surae in young female Lewis rats. Rats were injected with vehicle or peptidoglycan-polysaccharide (PG-PS) to induce long-lasting inflammation. The PG-PS reduced gastrocnemius muscle mass in both legs, but that of the SSC-trained leg was significantly greater than that of the contralateral leg. Circulating pro-inflammatory cytokines, such as IL-1β, were significantly increased by PG-PS injection, even if carrying out SSC. The circulating anti-inflammatory cytokine IL-10 increased with SSC in both healthy and inflammatory conditions. Stretch-shortening contraction also prevented increases in serum aspartate aminotransferase activity and plasma free phenylalanine concentration induced by PG-PS, in comparison to the control resistance exercise consisting of isometric contractions. Moreover, aspartate aminotransferase and phenylalanine concentrations demonstrated a significant and negative correlation with IL-10/IL-1β values (r = -0.61, P = 0.017, and r = -0.66, P = 0.008, respectively). These results suggest that SSC training is effective to reduce both muscle atrophy and the hepatic dysfunction induced by PG-PS, mediated, at least in part, through an increase in circulating IL-10.

Impact of Skeletal Muscle Mass on Metabolic Health

Skeletal muscle is regarded as an endocrine and paracrine organ. Muscle-derived secretory proteins, referred to as myokines, mediate interactions between skeletal muscle mass and other organs such as the liver, adipose tissue, pancreas, bone, and the cardiovascular system. As individuals age, reduced levels of physical activity and sarcopenia (loss of skeletal muscle mass and strength) are associated with physical frailty and disability. Recently, several studies have suggested that the loss of skeletal muscle mass may contribute to metabolic disease. Therefore, herein, we focus on the relationships between skeletal muscle mass and metabolic diseases, including metabolic syndrome and non-alcoholic fatty liver disease.

Connective tissue growth factor in hepatocytes is elevated by carbon tetrachloride via STAT3 activation

Carbon tetrachloride (CCl4) is widely used to induce hepatic fibrosis. Therapeutic agents alleviate hepatic fibrosis by inhibiting signal transducer and activator of transcription 3 (STAT3) activation. To understand the direct effects of CCl4 on STAT3 expression in the liver, the present study incubated cultured hepatocytes expressing connective tissue growth factor (CTGF) with CCl4. Rats exposed to CCl4 for 8 weeks exhibited hepatic fibrosis, which was confirmed through the assessment of plasma biomarkers. Isolated liver samples were used to determine the protein levels of CTGF and STAT3 using western blotting. In addition, STAT3 expression was silenced in α mouse liver 12 (AML‑12) cells using small interfering RNA transfection. In addition, a pharmacological inhibitor, stattic, was used to inhibit STAT3 expression. The incubation of AML‑12 cells with CCl4 induced a dose‑dependent increase in CTGF expression and STAT3 activation. Notably, silymarin, an extract from milk thistle, inhibited these changes in AML‑12 cells and the antioxidant tiron produced similar effects. Silencing of STAT3 reduced the CTGF expression promoted by CCl4 in the hepatocytes. Additionally, similar to tiron, stattic inhibited CTGF expression induced by CCl4. In conclusion, CCl4 may activate STAT3 through oxidative stress to promote CTGF expression, which is one of the main factors contributing to the risk of hepatic fibrosis.

Creatinine-to-bodyweight ratio is a predictor of incident non-alcoholic fatty liver disease: A population-based longitudinal study

AIM

Serum creatinine (Cre) is used as a surrogate marker of muscle mass. We investigated the impact of the Cre-to-bodyweight (BW) ratio (Cre/BW) on incident non-alcoholic fatty liver disease (NAFLD).

METHODS

Fatty liver disease was diagnosed by abdominal ultrasonography. In this historical cohort study of 13 728 participants (6397 men and 7331 women), we divided the participants into two groups by sex and into quartiles according to Cre (mg/dL)/BW (kg; Q1-4). We carried out Cox proportional hazard models, adjusting for age, alanine aminotransferase, fasting plasma glucose, systolic blood pressure, alcohol consumption, smoking status, and exercise.

RESULTS

During the 5.1-year follow up for men and 6.0-year follow up for women, 2497 participants (1696 men, 801 women) developed NAFLD. The 4000-days cumulative incidence rates of FLD for men and women were 29.6% and 16.6% in Q1, 28.2% and 10.6% in Q2, 25.5% and 8.8% in Q3, and 22.7% and 7.7% in Q4, respectively. The hazard ratios of incident NAFLD in Q1 (Cre/BW [×100]: men <1.28; women <1.17) were 1.89 (95% confidence interval 1.64-2.17, P < 0.001) in men and 2.96 (2.42-3.62, P < 0.001) in women, compared with Q4 (Cre/BW [×100]: men ≥1.61; women ≥1.51).

CONCLUSIONS

A low Cre/BW is associated with an increased risk of NAFLD. Screening Cre/BW can be used to identify individuals who are at high risk of NAFLD.

Relationship between relative skeletal muscle mass and nonalcoholic fatty liver disease: a systematic review and meta-analysis

BACKGROUND AND AIM

Nonalcoholic fatty liver disease (NAFLD) has gradually become one of the most common chronic liver diseases in the world. More and more evidence shows that low skeletal muscle mass index (SMI) may play a role in the development of NAFLD. Our aim was to quantify the association between SMI, sarcopenia and the presence and severity of NAFLD.

METHODS

We systematically searched English relevant studies from PubMed, Embase, the Web of Science and the Cochrane Library updated to December 20th, 2018. Studies in which SMI was compared between NAFLD cases and controls were included. So were studies concerning the odds ratio (OR) of NAFLD, non-alcoholic steatohepatitis (NASH) and significant fibrosis in sarcopenia patients. Pooled weighted mean differences and ORs were calculated.

RESULTS

Of the 1331 retrieved studies, 19 articles were included. SMI level in NAFLD patients was 1.77 (95% CI 1.15, 2.39) lower than that in normal controls. We also found a significantly higher occurrence risk of NAFLD (OR = 1.33, 95% CI 1.20 to 1.48), NASH (OR = 2.42, 95% CI 1.27 to 3.57) and NAFLD-related significant fibrosis (OR = 1.56, 95% CI 1.34, 1.78) in sarcopenia subjects.

CONCLUSIONS

SMI level in patients with NAFLD was lower than healthy people, and patients with sarcopenia have higher occurrence risk of NAFLD, as well as its advanced stages including NASH or NAFLD-related significant fibrosis. Further well-designed prospective studies are required to strengthen the arguments.

A Low Creatinine to Body Weight Ratio Predicts the Incident Nonalcoholic Fatty Liver Disease in Nonelderly Chinese without Obesity and Dyslipidemia: A Retrospective Study

AIM

A lower ratio of creatinine to body weight (Cr/BW) is considered the independent risk factor for incident nonalcoholic fatty liver disease (NAFLD). However, the relationship between the Cr/BW ratio and NAFLD among individuals without obesity and dyslipidemia and how this relationship is impacted by age are still ambiguous. Therefore, we explored the effect of the Cr/BW ratio on the incident NAFLD among Chinese without obesity and dyslipidemia of different age groups.

METHODS

A total of 9756 participants without NAFLD at baseline were included and grouped by the median value (1.32) of the Cr/BW ratio. Then, a further analysis was stratified by age (60 years old). The primary outcome was new-onset NAFLD.

RESULTS

After a median follow-up of 2.76 years, 844 (8.7%) participants developed NAFLD. The elderly had a higher person-years incidence rate and cumulative incidence rate than the nonelderly. A high Cr/BW ratio showed a lower cumulative incidence compared to a low Cr/BW ratio for the whole population (P = 0.039) and the nonelderly group (P = 0.008). After being adjusted for multivariate variables, the lower Cr/BW ratio was the independent risk factor for incident NAFLD in the nonelderly (HR 0.718, 95% CI 0.548-0.942), instead of the elderly.

CONCLUSIONS

The Cr/BW ratio has a negative relationship with incident NAFLD among nonobese Chinese without dyslipidemia before the age of 60.

Promotion of Adropin Expression by Hyperglycemia Is Associated with STAT3 Activation in Diabetic Rats

BACKGROUND

Adropin is a secreted polypeptide that has been demonstrated to play an important role in energy homeostasis and lipid metabolism. Signal transducer and activator of transcription 3 (STAT3) may promote the transcription of target genes including adropin. In the current study, we investigated the effect of adropin on glucose metabolism in diabetic rats and the mechanism that governs this effect was subsequently assessed.

MATERIALS AND METHODS

Rats received a single injection of streptozotocin to induce type 1 diabetes. The diabetic rats were treated with insulin or phloridzin, another antidiabetic agent through inhibition of glucose reabsorption, for 7 days. Plasma glucose levels and adropin levels were measured. The interaction between STAT3 and adropin was evaluated using the human hepatoma HepG2 cell line. HepG2 cells were pretreated with the specific antagonist Stattic or with STAT3-specific siRNAs to knockout STAT3. Changes in energy homeostasis-associated gene expression were measured using real-time PCR. The protein expression levels of pSTAT3 and STAT3 were measured using Western blotting.

RESULTS

In diabetic rats, the serum concentrations of adropin were increased in the vehicle-treated group and decreased in the insulin- or phloridzin-treated group. In liver tissues, the Enho expression level and the activity of STAT3 also showed similar tendencies. After HepG2 cells were treated with medium containing high glucose, the ratio of p-STAT3 to STAT3, Enho mRNA levels and reactive oxygen species expression levels in HepG2 cells were significantly increased in conjunction with increased glucose levels. The effect was inhibited after pretreatment with Stattic or knockdown with STAT3-specific siRNAs.

CONCLUSION

STAT3 is involved in the genetic regulation of adropin, increasing the levels of circulating adropin and promoting Enho expression in the livers of diabetic rats.

The Atypical Cannabinoid Abn-CBD Reduces Inflammation and Protects Liver, Pancreas, and Adipose Tissue in a Mouse Model of Prediabetes and Non-alcoholic Fatty Liver Disease

Background and Aims: The synthetic atypical cannabinoid Abn-CBD, a cannabidiol (CBD) derivative, has been recently shown to modulate the immune system in different organs, but its impact in obesity-related meta-inflammation remains unstudied. We investigated the effects of Abn-CBD on metabolic and inflammatory parameters utilizing a diet-induced obese (DIO) mouse model of prediabetes and non-alcoholic fatty liver disease (NAFLD). Materials and Methods: Ten-week-old C57Bl/6J mice were fed a high-fat diet for 15 weeks, following a 2-week treatment of daily intraperitoneal injections with Abn-CBD or vehicle. At week 15 mice were obese, prediabetic and developed NAFLD. Body weight and glucose homeostasis were monitored. Mice were euthanized and blood, liver, adipose tissue and pancreas were collected and processed for metabolic and inflammatory analysis. Results: Body weight and triglycerides profiles in blood and liver were comparable between vehicle- and Abn-CBD-treated DIO mice. However, treatment with Abn-CBD reduced hyperinsulinemia and markers of systemic low-grade inflammation in plasma and fat, also promoting white adipose tissue browning. Pancreatic islets from Abn-CBD-treated mice showed lower apoptosis, inflammation and oxidative stress than vehicle-treated DIO mice, and beta cell proliferation was induced. Furthermore, Abn-CBD lowered hepatic fibrosis, inflammation and macrophage infiltration in the liver when compared to vehicle-treated DIO mice. Importantly, the balance between hepatocyte proliferation and apoptosis was improved in Abn-CBD-treated compared to vehicle-treated DIO mice. Conclusions: These results suggest that Abn-CBD exerts beneficial immunomodulatory actions in the liver, pancreas and adipose tissue of DIO prediabetic mice with NAFLD, thus protecting tissues. Therefore, Abn-CBD and related compounds could represent novel pharmacological strategies for managing obesity-related metabolic disorders.