Circulating leptin in patients with nonalcoholic fatty liver disease-related liver fibrosis: a systematic review and a meta-analysis

Adipokine/hepatokines profiling of fatty liver in adolescents and young adults: cross-sectional and prospective analyses of the BCAMS study

OBJECTIVE

The underlying connections between obesity and non-alcoholic fatty liver disease (NAFLD) are not fully understood. One potential link might be the imbalanced adipokines and hepatokines. We aimed to explore the associations between specific adipokines/hepatokines and NAFLD in Chinese youth and to determine how these biomarkers mediate the obesity-NAFLD relationship.

METHODS

We analyzed data from the 10-year follow-up visit of the Beijing Children and Adolescents Metabolic Syndrome (BCAMS) study (n = 509; mean age = 20.2 years) for a comprehensive metabolic risk assessment, including liver ultrasound and plasma measurements of adiponectin, leptin, fibroblast growth factor 21 (FGF21), retinol-binding protein 4 (RBP4), and angiopoietin-like protein 8 (ANGPTL8). Longitudinal analysis was performed on a subgroup (n = 307), with complete baseline (mean age = 12.2 years) and follow-up data. Mediation models assessed how obesity at baseline and follow-up influence NAFLD through these biomarkers.

RESULTS

Participants with NAFLD exhibited a high prevalence of central obesity (90.9%). Both cross-sectional and prospective analyses identified increased RBP4, FGF21, leptin, and decreased adiponectin levels as significant predictors of NAFLD. More adipokine/hepatokine abnormalities were linked to higher NAFLD risk. Furthermore, ratios reflecting adipokine/hepatokine imbalances, including leptin/adiponectin, FGF21/adiponectin, and RBP4/adiponectin, demonstrated stepwise changes correlating with NAFLD severity (all p < 0.05). Mediation analysis indicated that these four adipokines/hepatokines accounted for approximately 72.4% of the central obesity-NAFLD relationship and 80.1% in the subgroup analysis using baseline childhood data.

CONCLUSIONS

Dysregulated adipokines/hepatokines may explain the onset or progression of obesity-related NAFLD in youths. Higher RBP4, FGF21 and leptin, alongside lower adiponectin, could serve as early biomarkers for NAFLD.

Crosstalk between fat tissue and muscle, brain, liver, and heart in obesity: cellular and molecular perspectives

A high-fat diet and physical inactivity are key contributors to obesity, predisposing individuals to various chronic diseases, such as cardiovascular disease and diabetes, which involve multiple organs and tissues. To better understand the role of multi-organ interaction mechanisms in the rising incidence of obesity and its associated chronic conditions, treatment and prevention strategies are being extensively investigated. This review examines the signaling mechanisms between different tissues and organs, with a particular focus on the crosstalk between adipose tissue and the muscle, brain, liver, and heart, and potentially offers new strategies for the treatment and management of obesity and its complications.

Redox Homeostasis and Non-Invasive Assessment of Significant Liver Fibrosis by Shear Wave Elastography

Hepatic fibrosis with various origins can be estimated non-invasively by using certain biomarkers and imaging-based measurements. The aim of our study was to examine redox homeostasis biomarkers and liver stiffness measurements for the assessment of significant liver fibrosis in different etiologies of chronic liver diseases. A cohort study consisting of 88 chronic liver disease patients of both sexes (age 49.1 ± 14.7 years) was performed. Cytokine profiles as well as redox homeostasis characteristics were determined. Liver fibrosis stages were assessed with shear wave elastography. The plasma levels of four cytokines showed no significant alteration between the four fibrotic stages; however, higher values were measured in the F2-4 stages. Free sulfhydryl group concentration, the marker of redox homeostasis, was lower in significant fibrosis (F0-F1: 0.36 ± 0.06 vs. F2-4: 0.29 ± 0.08 mmol/L, p < 0.05). Higher chemiluminescence values, as free radical-antioxidant parameters, were detected in advanced fibrosis stages in erythrocytes (F0-F1: 36.00 ± 37.13 vs. F2-4: 51.47 ± 44.34 RLU%). These data suggest that oxidative stress markers can predict significant fibrosis, with the aim of reducing the number of protocol liver biopsies in patients unlikely to have significant disease; however, their role in distinguishing between the certain fibrosis groups needs further studies.

Non-Invasive Assessment of Metabolic Dysfunction-Associated Steatotic Liver Disease in Adolescents with Severe Obesity; Patient Characteristics and Association with Leptin-A Cross-Sectional Overview of Baseline Data from a RCT

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common liver disease in adolescents with obesity. Nonetheless, the guidelines for screening and managing this disease are contradictory. The purpose of this study is to non-invasively assess the prevalence, patient characteristics, and potential associated factors of MASLD in this demographic. Methods: This study used baseline data from an RCT in adolescents eligible for bariatric surgery. MASLD was determined by measuring the hepatorenal index (HRI) with ultrasonography, blood liver tests, and the fatty liver index (FLI). Results: A total of 56 adolescents enrolled in the analyses; the majority were female n = 44 (79%); the mean age was 15.75 (±1.01) years; the average body mass index (BMI) was 44.08 (±5.16) kg/m2. In 35 (62.5%) of the patients, the HRI was abnormal. This group had a higher waist/hip ratio, elevated liver biochemistry, and significantly lower leptin levels (mean difference = -46.35, 95% CI -76.72, -15.99) compared to the group with a normal HRI. In 32 (55.2%) of the patients, ALT levels were elevated and the FLI was abnormal in all (100%) participants. Linear regression analysis indicated associations between the HRI and typical anthropometric and metabolic measurements; and an inverse association between HRI and leptin B = -0.003 (95% CI -0.005, -0.00), independently of sex- and age-adjusted BMI. Conclusions: MASLD is highly prevalent in adolescents with severe obesity. However, the prevalence strongly depends on which tool is used, namely the HRI (62.5%), alanine transaminase levels (55.2%), and FLI (100%). Our findings suggest that leptin may be a valuable biomarker in supporting the diagnosis of MASLD.

Underlying Mechanisms behind the Brain-Gut-Liver Axis and Metabolic-Associated Fatty Liver Disease (MAFLD): An Update

Metabolic-associated fatty liver disease (MAFLD) includes several metabolic dysfunctions caused by dysregulation in the brain-gut-liver axis and, consequently, increases cardiovascular risks and fatty liver dysfunction. In MAFLD, type 2 diabetes mellitus, obesity, and metabolic syndrome are frequently present; these conditions are related to liver lipogenesis and systemic inflammation. This study aimed to review the connection between the brain-gut-liver axis and MAFLD. The inflammatory process, cellular alterations in hepatocytes and stellate cells, hypercaloric diet, and sedentarism aggravate the prognosis of patients with MAFLD. Thus, to understand the modulation of the physiopathology of MAFLD, it is necessary to include the organokines involved in this process (adipokines, myokines, osteokines, and hepatokines) and their clinical relevance to project future perspectives of this condition and bring to light new possibilities in therapeutic approaches. Adipokines are responsible for the activation of distinct cellular signaling in different tissues, such as insulin and pro-inflammatory cytokines, which is important for balancing substances to avoid MAFLD and its progression. Myokines improve the quantity and quality of adipose tissues, contributing to avoiding the development of MAFLD. Finally, hepatokines are decisive in improving or not improving the progression of this disease through the regulation of pro-inflammatory and anti-inflammatory organokines.