The relationship between Lipocalin-2 level and hepatic steatosis in obese patients with NAFLD after bariatric surgery

Background Lipocalin-2 (LCN2) has a critical effect on obesity as well as its associated comorbidities. The present study focused on analyzing serum LCN2 levels of obese patients with nonalcoholic fatty liver disease (NAFLD) and on determining relationship of hepatic steatosis improvement with LCN2 levels after laparoscopic sleeve gastrectomy (LSG). Methods This work enrolled ninety patients with obesity and NAFLD. Twenty-three of them underwent LSG. Anthropometric and biochemical parameters and serum LCN2 levels were determined at baseline and those at 6-month post-LSG. Controlled attenuation parameter (CAP) measured by FibroScan was adopted for evaluating hepatic steatosis. Results Among severe obesity patients, serum LCN2 levels were significantly increased (111.59 ± 51.16 ng/mL vs. 92.68 ± 32.68 ng/mL, P = 0.035). The CAP value was higher indicating higher liver fat content (360.51 ± 45.14 dB/m vs. 340.78 ± 45.02 dB/m, P = 0.044). With regard to surgical patients, liver function, glucose, and lipid levels were significantly improved after surgery. Serum LCN2 levels significantly decreased (119.74 ± 36.15 ng/mL vs. 87.38 ± 51.65 ng/mL, P = 0.001). Decreased CAP indicated a significant decrease in liver fat content (358.48 ± 46.13 dB/m vs. 260.83 ± 69.64 dB/m, P < 0.001). The decrease in LCN2 levels was significantly related to the reduced hepatic fat content and improvement in steatosis grade after adjusting for gender, age, and BMI decrease. Conclusions Serum LCN2 levels are related to obesity and NAFLD. The decreased serum LCN2 levels could be an indicator of hepatic steatosis improvement.

Validation of a Quantification Method for Curcumin Derivatives and Their Hepatoprotective Effects on Nonalcoholic Fatty Liver Disease

Curcumin (CM), demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC) are major curcumin derivatives found in the rhizome of turmeric (Curcuma longa L.), and have yielded impressive properties to halt various diseases. In the present study, we carried out a method validation for curcumin derivatives and analyzed the contents simultaneously using HPLC with UV detection. For validation, HPLC was used to estimate linearity, range, specificity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). Results showed a high linearity of the calibration curve, with a coefficient of correlation (R2) for CM, DMC, and BDMC of 0.9999, 0.9999, and 0.9997, respectively. The LOD values for CM, DMC, and BDMC were 1.16, 1.03, and 2.53 ng/μL and LOQ values were 3.50, 3.11, and 7.67 ng/μL, respectively. Moreover, to evaluate the ability of curcumin derivatives to reduce liver lipogenesis and compare curcumin derivatives’ therapeutic effects, a HepG2 cell model was established to analyze their hepatoprotective properties. Regarding the in vivo study, we investigated the effect of DMC, CM, and BDMC on nonalcoholic fatty liver disease (NAFLD) caused by a methionine choline deficient (MCD)-diet in the C57BL/6J mice model. From the in vitro and in vivo results, curcumin derivatives alleviated MCD-diet-induced lipid accumulation as well as high triglyceride (TG) and total cholesterol (TC) levels, and the protein and gene expression of the transcription factors related to liver adipogenesis were suppressed. Furthermore, in MCD-diet mice, curcumin derivatives suppressed the upregulation of toll-like receptors (TLRs) and the production of pro-inflammatory cytokines. In conclusion, our findings indicated that all of the three curcuminoids exerted a hepatoprotective effect in the HepG2 cell model and the MCD-diet-induced NAFLD model, suggesting a potential for curcuminoids derived from turmeric as novel therapeutic agents for NAFLD.

Mechanisms of liver injury in high fat sugar diet fed mice that lack hepatocyte X-box binding protein 1

Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of liver diseases in the United States and can progress to cirrhosis, end-stage liver disease and need for liver transplantation. There are limited therapies for NAFLD, in part, due to incomplete understanding of the disease pathogenesis, which involves different cell populations in the liver. Endoplasmic reticulum stress and its adaptative unfolded protein response (UPR) signaling pathway have been implicated in the progression from simple hepatic steatosis to nonalcoholic steatohepatitis (NASH). We have previously shown that mice lacking the UPR protein X-box binding protein 1 (XBP1) in the liver demonstrated enhanced liver injury and fibrosis in a high fat sugar (HFS) dietary model of NAFLD. In this study, to better understand the role of liver XBP1 in the pathobiology of NAFLD, we fed hepatocyte XBP1 deficient mice a HFS diet or chow and investigated UPR and other cell signaling pathways in hepatocytes, hepatic stellate cells and immune cells. We demonstrate that loss of XBP1 in hepatocytes increased inflammatory pathway expression and altered expression of the UPR signaling in hepatocytes and was associated with enhanced hepatic stellate cell activation after HFS feeding. We believe that a better understanding of liver cell-specific signaling in the pathogenesis of NASH may allow us to identify new therapeutic targets.

MAFLD/NAFLD Biopsy-Free Scoring Systems for Hepatic Steatosis, NASH, and Fibrosis Diagnosis

Metabolic dysfunction-associated fatty liver disease (MAFLD), formerly known as nonalcoholic fatty liver disease, is the most prevalent liver disorder worldwide. Historically, its diagnosis required biopsy, even though the procedure has a variable degree of error. Therefore, new non-invasive strategies are needed. Consequently, this article presents a thorough review of biopsy-free scoring systems proposed for the diagnosis of MAFLD. Similarly, it compares the severity of the disease, ranging from hepatic steatosis (HS) and nonalcoholic steatohepatitis (NASH) to fibrosis, by contrasting the corresponding serum markers, clinical associations, and performance metrics of these biopsy-free scoring systems. In this regard, defining MAFLD in conjunction with non-invasive tests can accurately identify patients with fatty liver at risk of fibrosis and its complications. Nonetheless, several biopsy-free scoring systems have been assessed only in certain cohorts; thus, further validation studies in different populations are required, with adjustment for variables, such as body mass index (BMI), clinical settings, concomitant diseases, and ethnic backgrounds. Hence, comprehensive studies on the effects of age, morbid obesity, and prevalence of MAFLD and advanced fibrosis in the target population are required. Nevertheless, the current clinical practice is urged to incorporate biopsy-free scoring systems that demonstrate adequate performance metrics for the accurate detection of patients with MAFLD and underlying conditions or those with contraindications of biopsy.

Sex-specific contribution of lipid accumulation product and cardiometabolic index in the identification of nonalcoholic fatty liver disease among Chinese adults

Background Lipid accumulation product (LAP) and cardiometabolic index (CMI) are two novel obesity-related indexes associated with enhancing metabolic disease (MD) risk. Current evidences suggest that the differences in sex hormones and regional fat distribution in both sexes are directly correlated with MD and nonalcoholic fatty liver disease (NAFLD) risk. Hence, NAFLD incidences reflect sex differences. Herein, we examined the accuracy of LAP and CMI in diagnosing NAFLD in both sexes. Methods Overall, 14,407 subjects, who underwent health check-up in the northeastern China, were enrolled in this study, and their corresponding LAP and CMI were calculated. Abdominal ultrasonography was employed for NAFLD diagnosis. Multivariate analyses were analyzed potential correlations between LAP and/or CMI and NAFLD. Odds ratios (ORs) and 95% confidence intervals (CIs) were evaluated. Receiver operating characteristic curve analyses was executed for the exploration of the diagnostic accuracies. Areas under the curves (AUCs) with 95%CIs were calculated. Results NAFLD prevalence increased with elevated quartiles of LAP and CMI in both sexes. In multivariate logistic regression analyses, LAP and CM expressed as continuous variables or quartiles, significantly correlated with NAFLD. The ORs for the top versus bottom quartile of LAP and CMI for NAFLD were 13.183 (95%CI = 8.512–20.417) and 8.662 (95%CI = 6.371–11.778) in women and 7.544 (95%CI = 5.748–9.902) and 5.400 (95%CI = 4.297–6.786) in men. LAP and CMI exhibited larger AUCs, compared to other obesity-related indexes in terms of discriminating NAFLD. The AUCs of LAP and CMI were 0.860 (95%CI = 0.852–0.867) and 0.833 (95%CI = 0.825–0.842) in women and 0.816 (95%CI = 0.806–0.825) and 0.779 (95%CI = 0.769–0.789) in men. Conclusions LAP and CMI are convenient indexes for the screening and quantification of NAFLD within a Chinese adult population. Their associations with NAFLD are substantially greater in women than men.

The role and possible mechanism of the long noncoding RNA LINC01260 in nonalcoholic fatty liver disease

Objective To investigate the differential expression profile of lncRNAs in the nonalcoholic fatty liver disease (NAFLD) model induced by oleic acid (OA) and to further explore the role of LINC01260 (ENST00000255183) in NAFLD, providing theoretical support for the clinical value of lncRNAs in NAFLD. Methods OA (50 μg/mL) was used to induce steatosis in normal human LO2 hepatocytes for 48 h and was verified by Oil red O staining. Differential expression profiles of lncRNAs were obtained by eukaryotic circular sequencing (RNA/lncRNA/circRNA-seq) techniques. A gain-of-function (GOF) strategy for LINC01260 was adopted, Oil red O staining and semiquantitative analysis were combined to explore whether the GOF of LINC01260 affects LO2 cell steatosis. CeRNA-based bioinformatics analysis of lncRNAs was performed, and the enriched mRNAs were further verified. RXRB siRNAs were applied and verify its role in LINC01260 regulated OA-induced hepatocytes steatosis. Results Lipid droplets of different sizes were observed in the cells of the OA group. Absorbance in the OA group was significantly increased after isopropanol decolorization (P < 0.05). Compared with those in the control group, there were 648 lncRNAs with differential expression greater than 1 time in the OA group, of which 351 were upregulated and 297 were downregulated. Fluorescence quantitative PCR showed that the expression of LINC01260 in the OA group was downregulated by 0.35 ± 0.07-fold (P < 0.05). The formation of lipid droplets in LO2 cells of the LINC01260 GOF group decreased significantly (P < 0.05). CeRNA analysis indicated that the mRNA levels of RXRB, RNPEPL1, CD82, MADD and KLC2 were changed to different degrees. Overexpression of LINC01260 significantly induced RXRB transcription (P < 0.05) and translation, and RXRB silence attenuated the lipids decrease induced by LINC01260 overexpression. Conclusion The OA-induced NAFLD cell model has a wide range of lncRNA differential expression profiles. LINC01260 participates in the regulation of the lipid droplet formation process of NAFLD, and its overexpression can significantly inhibit the steatosis process of LO2 cells. Mechanistically, LINC01260 may act as a ceRNA to regulate the expression of RXRB, thereby affecting the adipocytokine signaling pathway.

Aurantio-Obtusin Attenuates Non-Alcoholic Fatty Liver Disease Through AMPK-Mediated Autophagy and Fatty Acid Oxidation Pathways

Nonalcoholic fatty liver disease (NAFLD), manifested as the aberrant accumulation of lipids in hepatocytes and inflammation, has become an important cause of advanced liver diseases and hepatic malignancies worldwide. However, no effective therapy has been approved yet. Aurantio-obtusin (AO) is a main bioactive compound isolated from Cassia semen that has been identified with multiple pharmacological activities, including improving adiposity and insulin resistance. However, the ameliorating effects of AO on diet-induced NAFLD and underlying mechanisms remained poorly elucidated. Our results demonstrated that AO significantly alleviated high-fat diet and glucose-fructose water (HFSW)-induced hepatic steatosis in mice and oleic acid and palmitic acid (OAPA)-induced lipid accumulation in hepatocytes. Remarkably, AO was found to distinctly promote autophagy flux and influence the degradation of lipid droplets by inducing AMPK phosphorylation. Additionally, the induction of AMPK triggered TFEB activation and promoted fatty acid oxidation (FAO) by activating PPARα and ACOX1 and decreasing the expression of genes involved in lipid biosynthesis. Meanwhile, the lipid-lowing effect of AO was significantly prevented by the pretreatment with inhibitors of autophagy, PPARα or ACOX1, respectively. Collectively, our study suggests that AO ameliorates hepatic steatosis via AMPK/autophagy- and AMPK/TFEB-mediated suppression of lipid accumulation, which opens new opportunities for pharmacological treatment of NAFLD and associated complications.