The potential role of omentin-1 in obesity-related metabolic dysfunction-associated steatotic liver disease: evidence from translational studies.

BACKGROUND: Obesity, characterized by visceral adipose tissue (VAT) expansion, is closely associated with metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). Recent research has highlighted the crucial role of the adipose tissue-liver axis in the development of MASLD. In this study, we investigated the potential role of omentin-1, a novel adipokine expressed by VAT, in obesity-related MASLD pathogenesis. METHODS: Through in silico analysis of differentially expressed genes in VAT from obese patients with and without MASH, we identified omentin-1 as a significant candidate. To validate our findings, we measured omentin-1 levels in VAT and plasma of lean controls and obese patients with biopsy-proven MASLD. Additionally, we assessed omentin-1 expression in the VAT of diet-induced mice MASLD model. In vitro and ex vivo studies were conducted to investigate the effects of omentin-1 on MASLD-related mechanisms, including steatosis, inflammation, endoplasmic reticulum (ER) stress, and oxidative stress. We also analyzed the impact of D-glucose and insulin on VAT omentin-1 levels ex vivo. RESULTS: Compared to the lean group, the obese groups exhibited significantly lower VAT and plasma levels of omentin-1. Interestingly, within the obese groups, omentin-1 is further decreased in MASH groups, independent of fibrosis. Likewise, VAT of mice fed with high-fat diet, showing histological signs of MASH showed decreased omentin-1 levels as compared to their control diet counterpart. In vitro experiments on fat-laden human hepatocytes revealed that omentin-1 did not affect steatosis but significantly reduced TNF-α levels, ER stress, and oxidative stress. Similar results were obtained using ex vivo VAT explants from obese patients upon omentin-1 supplementation. Furthermore, omentin-1 decreased the mRNA expression of NF-κB and mitogen-activated protein kinases (ERK and JNK). Ex vivo VAT explants showed that D-glucose and insulin significantly reduced omentin-1 mRNA expression and protein levels. CONCLUSIONS: Collectively, our findings suggest that reduced omentin-1 levels contribute to the development of MASLD. Omentin-1 supplementation likely exerts its beneficial effects through the inhibition of the NF-κB and MAPK signaling pathways, and it may additionally play a role in the regulation of glucose and insulin metabolism. Further research is warranted to explore omentin-1 as a potential therapeutic target and/or biomarker for MASLD.

Natural Compounds for Counteracting Nonalcoholic Fatty Liver Disease (NAFLD): Advantages and Limitations of the Suggested Candidates.

The booming prevalence of nonalcoholic fatty liver disease (NAFLD) in adults and children will threaten the health system in the upcoming years. The "multiple hit" hypothesis is the currently accepted explanation of the complex etiology and pathophysiology of the disease. Some of the critical pathological events associated with the development of NAFLD are insulin resistance, steatosis, oxidative stress, inflammation, and fibrosis. Hence, attenuating these events may help prevent or delay the progression of NAFLD. Despite an increasing understanding of the mechanisms involved in NAFLD, no approved standard pharmacological treatment is available. The only currently recommended alternative relies on lifestyle modifications, including diet and physical activity. However, the lack of compliance is still hampering this approach. Thus, there is an evident need to characterize new therapeutic alternatives. Studies of food bioactive compounds became an attractive approach to overcome the reticence toward lifestyle changes. The present study aimed to review some of the reported compounds with beneficial properties in NAFLD; namely, coffee (and its components), tormentic acid, verbascoside, and silymarin. We provide details about their protective effects, their mechanism of action in ameliorating the critical pathological events involved in NAFLD, and their clinical applications.

The Beneficial Effects of Triterpenic Acid and Acteoside in an In Vitro Model of Nonalcoholic Steatohepatitis (NASH).

Triterpenic acid (TA) and acteoside (ACT), the major components of APPLIVER and ACTEOS, respectively, have been reported to exert hepatoprotective effects, but the molecular mechanisms remain elusive, particularly in the NAFLD/NASH context. We assessed their effects in our well-established in vitro model resembling the pathophysiological mechanisms involved in NASH. Human hepatocytes and hepatic stellate cells were exposed to free fatty acids (FFA) alone or in combination with APPLIVER and ACTEOS as a mono- or co-culture. Steatosis, inflammation, generation of reactive oxygen species (ROS), and collagen deposition were determined. ACTEOS reduced both the TNF-α and ROS production, and, most importantly, attenuated collagen deposition elicited by the excess of FFA in the co-culture model. APPLIVER also showed inhibition of both TNF-α production and collagen deposition caused by FFA accumulation. The compounds alone did not induce any cellular effects. The present study showed the efficacy of APPLIVER and ACTEOS on pathophysiological mechanisms related to NASH. These in vitro data suggest that these compounds deserve further investigation for possible use in NASH treatment.

Ficolin-2 Plasma Level Assesses Liver Fibrosis in Non-Alcoholic Fatty Liver Disease.

Fibrosis is the strongest predictor for disease-specific mortality in non-alcoholic fatty liver diseases (NAFLD), but the need for liver biopsy limits its diagnosis. We assessed the performance of plasma ficolin-2 (FCN-2) as a biomarker of fibrosis identified by an in silico discovery strategy. Two hundred and thirty-five morbidly obese (MO) subjects with biopsy-proven NAFLD stratified by fibrosis stage (F0, n = 44; F1, n = 134; F2, n = 46; F3/F4, n = 11) and 40 cirrhotic patients were enrolled. The cohort was subdivided into discovery (n = 76) and validation groups (n = 159). The plasma level of FCN-2 and other candidate markers was determined. FCN-2 was inversely correlated with the stage of liver fibrosis (ρ = −0.49, p < 0.001) independently of steatosis (p = 0.90), inflammation (p = 0.57), and ballooning (p = 0.59). In the global cohort, FCN-2 level decreased significantly in a stepwise fashion from F0/F1 (median 4753 ng/mL) to F2−F3−F4 (2760 ng/mL) and in cirrhotic subjects (1418 ng/mL). The diagnostic performance of FCN-2 in detecting F ≥ 2 was higher than other indexes (APRI, FIB-4) (AUROC 0.82, 0.68, and 0.6, respectively). The accuracy improved when combined with APRI score and HDL values (FCNscore, AUROC 0.85). Overall, the FCN-2 plasma level can accurately discriminate liver fibrosis status (minimal vs. moderate/advanced) significantly improving the fibrosis diagnostic algorithms.

Association of Circulating Serum miR-34a and miR-122 with Dyslipidemia among Patients with Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) covers a spectrum of diseases from simple steatosis to non-alcoholic steatohepatitis, with approximately 20% risk of progressing to fibrosis and cirrhosis. The aim of this study was to compare the relative expression levels of circulating miR-21, miR-34a, miR-122, miR-125b and miR-375 between healthy controls and NAFLD patients, and to assess the feasibility of microRNAs as potential biomarkers for NAFLD. A cross-sectional study was conducted to evaluate circulating serum miRNAs as potential diagnostic markers for NAFLD. Twenty-eight clinically diagnosed and histologically-confirmed NAFLD patients, as well as 36 healthy controls were enrolled in this study. The relative expression of serum microRNAs were calculated using the comparative cycle threshold with spiked-in C. elegans miR-39 as exogenous internal control. Serum levels of miR-34a and miR-122 were significantly higher in NAFLD patients than in healthy controls (P = <0.0001). Positive correlations were observed between serum miR-34a with very low density lipoprotein cholesterol (VLDL-C) and triglyceride levels. However, the expression levels of miR-34a and miR-122 did not correlate with the histological features of NAFLD. Interestingly, receiver operating characteristic (ROC) curve analysis revealed that miR-34a and miR-122 are potential markers for discriminating NAFLD patients from healthy controls with an area under the curve (AUC) values of 0.781 and 0.858, respectively. Serum levels of miR-34a and miR-122 were found to be significantly higher among NAFLD patients, and were positively correlated with VLDL-C and triglyceride levels. Thus, circulating miR-34a and miR-122 can be used as potential biomarkers for discriminating NAFLD patients from healthy controls. Larger cohorts are required to validate the utility of miR-34a and miR-122 in monitoring liver injury.

Complete genome sequence of chikungunya virus isolated in the Philippines.

Chikungunya virus is an alphavirus of the Togaviridae family, which causes a febrile illness with arthralgia in humans. We report here on the complete genome sequence of chikungunya virus strain CHIKV-13-112A isolated from a patient in the Philippines who was suspected to have dengue virus. Phylogenetic analysis revealed that the strain is of the Asian genotype.