Serum leptin and leptin resistance correlations with NAFLD in patients with type 2 diabetes

Team players in the pathogenesis of metabolic dysfunctions-associated steatotic liver disease: The basis of development of pharmacotherapy

Nutrient metabolism is regulated by several factors. Social determinants of health with or without genetics are the primary regulator of metabolism, and an unhealthy lifestyle affects all modulators and mediators, leading to the adaptation and finally to the exhaustion of cellular functions. Hepatic steatosis is defined by presence of fat in more than 5% of hepatocytes. In hepatocytes, fat is stored as triglycerides in lipid droplet. Hepatic steatosis results from a combination of multiple intracellular processes. In a healthy individual nutrient metabolism is regulated at several steps. It ranges from the selection of nutrients in a grocery store to the last step of consumption of ATP as an energy or as a building block of a cell as structural component. Several hormones, peptides, and genes have been described that participate in nutrient metabolism. Several enzymes participate in each nutrient metabolism as described above from ingestion to generation of ATP. As of now several publications have revealed very intricate regulation of nutrient metabolism, where most of the regulatory factors are tied to each other bidirectionally, making it difficult to comprehend chronological sequence of events. Insulin hormone is the primary regulator of all nutrients' metabolism both in prandial and fasting states. Insulin exerts its effects directly and indirectly on enzymes involved in the three main cellular function processes; metabolic, inflammation and repair, and cell growth and regeneration. Final regulators that control the enzymatic functions through stimulation or suppression of a cell are nuclear receptors in especially farnesoid X receptor and peroxisome proliferator-activated receptor/RXR ligands, adiponectin, leptin, and adiponutrin. Insulin hormone has direct effect on these final modulators. Whereas blood glucose level, serum lipids, incretin hormones, bile acids in conjunction with microbiota are intermediary modulators which are controlled by lifestyle. The purpose of this review is to overview the key players in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) that help us understand the disease natural course, risk stratification, role of lifestyle and pharmacotherapy in each individual patient with MASLD to achieve personalized care and target the practice of precision medicine. PubMed and Google Scholar databases were used to identify publication related to metabolism of carbohydrate and fat in states of health and disease states; MASLD, cardiovascular disease and cancer. More than 1000 publications including original research and review papers were reviewed.

Evidence That Peripheral Leptin Resistance in Omental Adipose Tissue and Liver Correlates with MASLD in Humans

Leptin regulates lipid metabolism, maximizing insulin sensitivity; however, peripheral leptin resistance is not fully understood, and its contribution to metabolic dysfunction-associated steatotic liver disease (MASLD) is unclear. This study evaluated the contribution of the leptin axis to MASLD in humans. Forty-three participants, mostly female (86.04%), who underwent cholecystectomy were biopsied. Of the participants, 24 were healthy controls, 8 had MASLD, and 11 had metabolic dysfunction-associated steatohepatitis (MASH). Clinical and biochemical data and the gene expression of leptin, leptin receptor (LEPR), suppressor of cytokine signaling 3 (SOCS3), sterol regulatory element-binding transcription factor 1 (SREBF1), stearoyl-CoA desaturase-1 (SCD1), and patatin-like phospholipase domain-containing protein 2 (PNPLA2), were determined from liver and adipose tissue. Higher serum leptin and LEPR levels in the omental adipose tissue (OAT) and liver with MASH were found. In the liver, LEPR was positively correlated with leptin expression in adipose tissue, and SOCS3 was correlated with SREBF1-SCD1. In OAT, SOCS3 was correlated with insulin resistance and transaminase enzymes (p < 0.05 for all. In conclusion, we evidenced the correlation between the peripheral leptin resistance axis in OAT-liver crosstalk and the complications of MASLD in humans.

Effect of Cytokeratin-18, C-peptide, MHR, and MACK-3 Biomarkers in Metabolic Dysfunction-Associated Fatty Liver Disease After Laparoscopic Sleeve Gastrectomy

Background

Laparoscopic sleeve gastrectomy (LSG) has emerged as a valuable treatment for various metabolic disorders, including metabolic dysfunction-associated fatty liver disease (MAFLD) in patients with obesity. Consequently, there is a pressing need to develop noninvasive biomarkers for diagnosing and monitoring disease progression.

Objectives

This study aimed to evaluate specific biomarkers, including Cytokeratin-18 (CK-18), C-peptide, monocyte to HDL cholesterol ratio (MHR), and MACK-3, in patients with obesity with MAFLD undergoing LSG.

Design

A prospective cohort study on patients with obesity before and 6 months after the LSG procedure.

Methods

70 patients with obesity with confirmed MAFLD, determined by Transient Elastography (TE), were pre- and 6 months postoperatively tested. Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), lipid profile, ghrelin, leptin, peptide YY, GLP-1, and liver fibrosis scores, including AST/ALT ratio (AAR), Fibrosis-4 index (FIB-4), and BARD Score were tested.

Results

BMI significantly decreased in all participants, with a % excess weight loss of 62.0% ± 15.4%. TE measurements revealed a significant postoperative reduction from 100% to 87.1% (P = .006). All selected biomarkers showed significant postoperative improvement-a significant association of CK-18 with MAFLD markers, including AAR, FIB-4, and BARD score, were found. MACK-3 had positive associations with FIB-4. C-peptide and MHR showed no association with MAFLD markers. Furthermore, there was a positive correlation between CK-18 and MACK-3 tests and between C-peptide and CK-18 and MACK-3. Additionally, a receiver operating characteristic (ROC) curve was constructed, with CK-18 performing the best, with an estimated area under the curve of 0.863.

Conclusion

Serum CK-18 outperformed other selected biomarkers in predicting and monitoring MAFLD in patients with obesity, suggesting its prospective utility in clinical practice. Further studies are needed to validate the accuracy of the MACK-3 test.

Comparative and Predictive Significance of Serum Leptin Levels in Non-alcoholic Fatty Liver Disease

Background Non-alcoholic fatty liver disease (NAFLD) has emerged as the single most common chronic non-viral liver disease. The burden of the disease on healthcare-providing services has increased tremendously. Although a liver biopsy is the most authentic laboratory investigation for scoring the disease progression, it is an invasive technique. Researchers are vigorously working to find alternate markers for the scoring purpose. Despite the importance and association of leptin with metabolic syndrome and its related disorders, there have been relatively fewer studies on serum leptin and its association with NAFLD. Objective This study aimed to investigate variations in serum leptin levels between subjects with and without fibrosis in NAFLD and to assess the predictive value of serum leptin levels in NAFLD subjects. Materials and methods The study comprised 130 NAFLD subjects from two tertiary care hospitals in Lahore along with 86 healthy controls that were age, gender, and BMI matched with the subjects. Based on the NAFLD fibrosis score (NFS), the subjects were divided into two sub-groups, subjects with simple steatosis and those with fibrosis. Fasting serum leptin, glucose, and insulin levels were measured using enzyme-linked immunosorbent assay (ELISA). The Kruskal-Wallis test was applied to find differences between the three groups and Fisher's exact test for categorical comparison. To assess the predictive value of serum leptin for steatosis and fibrosis in NAFLD subjects, receiver operation characteristic (ROC) curve analysis was implemented. Results The difference in serum leptin level was statistically highly significant (p-value <0.001), with leptin levels of 10 (17.1) ng/mL among controls, 20.5 (21) ng/mL in simple steatosis, and 21 (28.6) ng/mL in fibrosis. The area under the ROC curve was 0.67 and 0.52 for steatosis and fibrosis, respectively. The cut-off value of 12.2 ng/mL showed 70% sensitivity and 50% specificity for steatosis, while at a threshold of 18 ng/mL, leptin demonstrated 40% sensitivity and specificity for fibrosis. Conclusion In conclusion, this study found that serum leptin levels are higher in NAFLD subjects compared to healthy controls, and it is a good independent predictor for the detection of liver steatosis.

Fatty liver index (FLI): more than a marker of hepatic steatosis

Fatty liver index (FLI) was developed as a simple and accurate marker of hepatic steatosis. FLI is derived from an algorithm based on body mass index, waist circumference, and levels of triglycerides and gamma-glutamyltransferase, and it is widely used in clinical and epidemiological studies as a screening tool for discriminating between healthy and nonalcoholic fatty liver disease (NAFLD) subjects. However, a systematic review of the literature regarding FLI revealed that this index has more extensive relationships with biochemical and physiological parameters. FLI is associated with key parameters of lipid, protein and carbohydrate metabolism, hormones, vitamins and markers of inflammation, or oxidative stress. FLI can be a predictor or risk factor for a number of metabolic and nonmetabolic diseases and mortality. FLI is also used as an indicator for determining the effects of health-related prevention interventions, medications, and toxic substances on humans. Although in most cases, the exact mechanisms underlying these associations have not been fully elucidated, they are most often assumed to be mediated by insulin resistance, inflammation, and oxidative stress. Thus, FLI may be a promising marker of metabolic health due to its multiple associations with parameters of physiological and pathological processes. In this context, the present review summarizes the data from currently available literature on the associations between FLI and biochemical variables and physiological functions. We believe that this review will be of interest to researchers working in this area and can provide new perspectives and directions for future studies on FLI.

Adiponectin Resistance in Obesity: Adiponectin Leptin/Insulin Interaction

The adiponectin (APN) levels in obesity are negatively correlated with chronic subclinical inflammation markers. The hypertrophic adipocytes cause obesity-linked insulin resistance and metabolic syndrome. Furthermore, macrophage polarization is a key determinant regulating adiponectin receptor (AdipoR1/R2) expression and differential adiponectin-mediated macrophage inflammatory responses in obese individuals. In addition to decrease in adiponectin concentrations, the decline in AdipoR1/R2 messenger ribonucleic acid (mRNA) expression leads to a decrement in adiponectin binding to cell membrane, and this turns into attenuation in the adiponectin effects. This is defined as APN resistance, and it is linked with insulin resistance in high-fat diet-fed subjects. The insulin-resistant group has a significantly higher leptin-to-APN ratio. The leptin-to-APN ratio is more than twofold higher in obese individuals. An increase in expression of AdipoRs restores insulin sensitivity and β-oxidation of fatty acids via triggering intracellular signal cascades. The ratio of high molecular weight to total APN is defined as the APN sensitivity index (ASI). This index is correlated to insulin sensitivity. Homeostasis model of assessment (HOMA)-APN and HOMA-estimated insulin resistance (HOMA-IR) are the most suitable methods to estimate the metabolic risk in metabolic syndrome. While morbidly obese patients display a significantly higher plasma leptin and soluble (s)E-selectin concentrations, leptin-to-APN ratio, there is a significant negative correlation between leptin-to-APN ratio and sP-selectin in obese patients. When comparing the metabolic dysregulated obese group with the metabolically healthy obese group, postprandial triglyceride clearance, insulin resistance, and leptin resistance are significantly delayed following the oral fat tolerance test in the first group. A neuropeptide, Spexin (SPX), is positively correlated with the quantitative insulin sensitivity check index (QUICKI) and APN. APN resistance together with insulin resistance forms a vicious cycle. Despite normal or high APN levels, an impaired post-receptor signaling due to adaptor protein-containing pleckstrin homology domain, phosphotyrosine-binding domain, and leucine zipper motif 1 (APPL1)/APPL2 may alter APN efficiency and activity. However, APPL2 blocks adiponectin signaling through AdipoR1 and AdipoR2 because of the competitive inhibition of APPL1. APPL1, the intracellular binding partner of AdipoRs, is also an important mediator of adiponectin-dependent insulin sensitization. The elevated adiponectin levels with adiponectin resistance are compensatory responses in the condition of an unusual discordance between insulin resistance and APN unresponsiveness. Hypothalamic recombinant adeno-associated virus (rAAV)-leptin (Lep) gene therapy reduces serum APN levels, and it is a more efficient strategy for long-term weight maintenance.

Inter-organ crosstalk during development and progression of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is characterized by tissue-specific insulin resistance and pancreatic β-cell dysfunction, which result from the interplay of local abnormalities within different tissues and systemic dysregulation of tissue crosstalk. The main local mechanisms comprise metabolic (lipid) signalling, altered mitochondrial metabolism with oxidative stress, endoplasmic reticulum stress and local inflammation. While the role of endocrine dysregulation in T2DM pathogenesis is well established, other forms of inter-organ crosstalk deserve closer investigation to better understand the multifactorial transition from normoglycaemia to hyperglycaemia. This narrative Review addresses the impact of certain tissue-specific messenger systems, such as metabolites, peptides and proteins and microRNAs, their secretion patterns and possible alternative transport mechanisms, such as extracellular vesicles (exosomes). The focus is on the effects of these messengers on distant organs during the development of T2DM and progression to its complications. Starting from the adipose tissue as a major organ relevant to T2DM pathophysiology, the discussion is expanded to other key tissues, such as skeletal muscle, liver, the endocrine pancreas and the intestine. Subsequently, this Review also sheds light on the potential of multimarker panels derived from these biomarkers and related multi-omics for the prediction of risk and progression of T2DM, novel diabetes mellitus subtypes and/or endotypes and T2DM-related complications.

Adiponectin-leptin ratio for the early detection of lean non-alcoholic fatty liver disease independent of insulin resistance

BACKGROUND

Lean Non-alcoholic Fatty Liver Disease (NAFLD) shares a similar disease burden to those of their overweight counterparts and should be detected early. We hypothesized that the adiponectin-leptin ratio (AL ratio) could be a good marker for early detection of lean NAFLD independent of insulin resistance.

MATERIALS AND METHODS

A total of 575 adults without diabetes were enrolled in a community-based study. The subjects were stratified into the lean controls, lean NAFLD, simple overweight/obesity and overweight/obesity NAFLD groups according to body mass index (BMI) and ultrasonographic fatty liver indicators. Serum adiponectin and leptin levels were measured by enzyme-linked immunosorbent assay. Multivariate logistic regression analyses were performed to estimate the odds ratio of having NAFLD in relation to the tertiles of serum AL concentration after adjustment. Receiver operating characteristic (ROC) analyses were applied to evaluate the diagnostic performance of the AL ratio for NAFLD.

RESULTS

The mean age of the participants was 42.8 ± 11.5 years. Comparing with the lean controls, the odds of having lean NAFLD for the highest versus the lowest tertile of AL ratio was 0.28(95%CI: 0.12-0.69) after adjustment. Putting AL ratio, BMI, triglyceride, AST/ALT ratio to the diagnosis performance of NAFLD, the ROC was 0.85 (95% CI: 0.82-0.88), 0.83 (95% CI 0.78-0.87) and 0.86 (95% CI 081-0.91) for all NAFLD, NAFLD in women and NAFLD in men, respectively. (p < .001).

CONCLUSIONS

The study revealed that the AL ratio could be a good biomarker to early distinguish lean NAFLD patients from lean controls independent of insulin resistance. [AQ3]Key messagesThe prevalence of non-alcoholic fatty liver disease (NAFLD) increases globally and is related to liver diseases and metabolic dysfunctions. Lean subset of NAFLD shares a similar disease burden to those of their overweight counterparts and should be detected early.Adiponectin-leptin ratio were associated with the severity of steatosis and was a predictor of obese NAFLD better than each single adipokine. To date, there is no investigation that explores specifically for the relationship between lean NAFLD and AL ratio.Our study found that adiponectin-leptin ratio is a sole independent marker regardless of insulin resistance in lean NAFLD. Having lean NAFLD for the highest versus the lowest tertile of adiponectin-leptin ratio was 0.28(95%CI: 0.12-0.69) after adjustment of age, sex, current smoking, exercise habits, HOMA-IR and AST/ALT. ROC for the NAFLD performance is good for the early detection (0.85; 95% CI: 0.82-0.88). Further rigorous investigation is necessary and should be promptly performed.

High Intensity Interval Training can Ameliorate Hypothalamic Appetite Regulation in Male Rats with Type 2 Diabetes: The Role of Leptin

Disruption of leptin (LEP) signaling in the hypothalamus caused by type 2 diabetes (T2D) can impair appetite regulation. The aim of this study was to investigate whether the improvement in appetite regulation induced by high-intensity interval training (HIIT) in rats with T2D can be mediated by LEP signaling. In this study, 20 male Wister rats were randomly assigned to one of four groups: CO (non-type 2 diabetes control), T2D (type 2 diabetes), EX (non-type 2 diabetes exercise), and T2D + EX (type 2 diabetes + exercise).To induce T2D, a combination of a high-fat diet for 2 months and a single dose of streptozotocin (35 mg/kg) was administered. Rats in the EX and T2D + EX groups performed 4-10 intervals of treadmill running at 80-100% of their maximum velocity (Vmax). Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), serum levels of insulin (INS) and LEP (LEPS) as well as hypothalamic expression of LEP receptors (LEP-R), Janus kinase 2 (JAK-2), signal transducer and activator of transcription 3 (STAT-3), neuropeptide Y (NPY), agouti-related protein (AGRP), pro-opiomelanocortin cocaine (POMC), amphetamine-related transcript (CART), suppressor of cytokine signaling (SOCS3), forkhead box protein O1 (FOXO1) were assessed. ANOVA and Tukey post hoc tests were used to compare the results between the groups. The levels of LEPS and INS, as well as the levels of LEP-R, JAK-2, STAT-3, POMC, and CART in the hypothalamus were found to be higher in the T2D + EX group compared to the T2D group. On the other hand, the levels of HOMA-IR, NPY, AGRP, SOCS3, and FOXO1 were lower in the T2D + EX group compared to the T2D group (P < 0.0001). The findings of this study suggest that HIIT may improve appetite regulation in rats with T2D, and LEP signaling may play a crucial role in this improvement. Graphical abstract (leptin signaling in the hypothalamus), Leptin (LEP), Leptin receptor (LEP-R), Janus kinase 2 (JAK2), Signal transducer and activator of transcription 3 (STAT3), expressing Neuropeptide Y (NPY), Agouti-related protein (AGRP), anorexigenic neurons (expressing pro-opiomelanocortin cocaine (POMC), Amphetamine-related transcript (CART), suppressor of cytokine signaling (SOCS3), forkhead box protein O1 (FOXO1).

Impacts of Non-alcoholic Fatty Liver Disease on Acute Coronary Syndrome: Evidence and Controversies

PURPOSE OF REVIEW

Acute coronary syndrome (ACS) and non-alcoholic fatty liver disease (NAFLD) are two clinically common disease entities that share numerous risk factors. This review aimed to discuss the impacts of NAFLD on ACS.

RECENT FINDINGS

In an era of improved control of traditional risk factors, the substantial burden of cardiometabolic abnormalities has caused widespread concern. NAFLD is considered the hepatic component of metabolic syndrome, which can exert an impact on human health beyond the liver. Accumulating studies have demonstrated that NAFLD is closely related to cardiovascular disease, especially coronary artery disease. Interestingly, although recent data have suggested an association between NAFLD and the incidence and outcomes of ACS, the results are not consistent. In this review, we comprehensively summarized evidence and controversies regarding whether NAFLD is a contributor to either the development of ACS or worse outcomes in patients with ACS. The potential pathophysiological and molecular mechanisms involved in the impacts of NAFLD on ACS were also elucidated.

Metformin induces pyroptosis in leptin receptor-defective hepatocytes via overactivation of the AMPK axis

Metformin is the biguanide of hepatic insulin sensitizer for patients with non-alcohol fatty liver disease (NAFLD). Findings regarding its efficacy in restoring blood lipids and liver histology have been contradictory. In this study, we explore metformin's preventive effects on NAFLD in leptin-insensitive individuals. We used liver tissue, serum exosomes and isolated hepatocytes from high-fat diet (HFD)-induced Zucker diabetic fatty (ZDF) rats and leptin receptor (Lepr) knockout rats to investigate the correlation between hepatic Lepr defective and liver damage caused by metformin. Through immunostaining, RT-PCR and glucose uptake monitoring, we showed that metformin treatment activates adenosine monophosphate (AMP)-activated protein kinase (AMPK) and its downstream cytochrome C oxidase (CCO). This leads to overactivation of glucose catabolism-related genes, excessive energy repertoire consumption, and subsequent hepatocyte pyroptosis. Single-cell RNA sequencing further confirmed the hyper-activation of glucose catabolism after metformin treatment. Altogether, we showed that functional Lepr is necessary for metformin treatment to be effective, and that long-term metformin treatment might promote NAFLD progression in leptin-insensitive individuals. This provides important insight into the clinical application of metformin.

Effects of treatment of non-alcoholic fatty liver disease on heart failure with preserved ejection fraction

In the past few decades, non-alcoholic fatty liver disease (NAFLD) and heart failure with preserved ejection fraction (HFpEF) have become the most common chronic liver disease and the main form of heart failure (HF), respectively. NAFLD is closely associated with HFpEF by sharing common risk factors and/or by boosting systemic inflammation, releasing other secretory factors, and having an expansion of epicardial adipose tissue (EAT). Therefore, the treatments of NAFLD may also affect the development and prognosis of HFpEF. However, no specific drugs for NAFLD have been approved by the Food and Drug Administration (FDA) and some non-specific treatments for NAFLD are applied in the clinic. Currently, the treatments of NAFLD can be divided into non-pharmacological and pharmacological treatments. Non-pharmacological treatments mainly include dietary intervention, weight loss by exercise, caloric restriction, and bariatric surgery. Pharmacological treatments mainly include administering statins, thiazolidinediones, glucagon-like peptide-1 receptor agonists, sodium-glucose cotransporter 2 inhibitors, and metformin. This review will mainly focus on analyzing how these treatments may affect the development and prognosis of HFpEF.

Association of serum C-peptide with all-cause and cardiovascular disease mortality in ultrasound-defined nonalcoholic fatty liver disease

OBJECTIVE

To determine the prognostic value of C-peptide in long-term nonalcoholic fatty liver disease (NAFLD) mortality.

METHODS

A total of 4670 participants with NAFLD were enrolled in this study. Multivariable Cox regression models evaluated the links between C-peptide levels and all-cause and cardiovascular disease (CVD) mortality risk using adjusted hazard ratios (aHR). In addition, a two‑piecewise Cox model with penalized splines was adapted to investigate the nonlinear relationships between C-peptide and mortality.

RESULTS

After a mean follow‑up period of 20 years, 1714 deaths from all causes were recorded. In an adjusted Cox regression analysis, using the low C-peptide group as the reference (quartile 1), higher C-peptide (quartile 4) was notably associated with increased all-cause mortality (aHR =1.39; 95% CI: 1.18-1.65) and CVD death (aHR = 1.97; 95% CI: 1.41-2.76). Spline analyses demonstrated that the association between C-peptide levels and all-cause mortality was U-shaped, with a threshold value of 0.41 nmol/L. Below the threshold, every one-unit increment in C-peptide had a 70% reduced risk of all-cause death (aHR = 0.30, 95% CI: 0.1-0.7). Above the threshold, the C-peptide levels were associated with a higher probability of all-cause death (aHR = 1. 3, 95% CI:1.2-1.4).

CONCLUSIONS

In the US NAFLD population defined by ultrasound, a U-shaped association was detected between baseline serum C-peptide level and all-cause mortality.

Effect of Gender on Serum Leptin in Type 2 Diabetes Mellitus: A System Review and Meta-Analysis

Objective

To assess the effect of gender factors on serum leptin levels in patients with diabetes mellitus.

Methods

To remove any studies that indicated a relationship between leptin-based inflammatory variables and the prevalence of type 2 diabetes in particular patient categories, a comprehensive search of all articles published between July 2019 and June 2021 was performed on PubMed/MEDLINE, Web of Science, Scopus, and EBSCO Host, including Academic Search Premier, Africa-Wide Information, and Cumulative Index to Nursing and Allied Health Literature. A summary description of the combined analysis across multiple centers, regions, and continents will help us better understand the effect of gender on serum leptin levels in patients with diabetes. The meta-analysis was performed using RevMan 5.2 software on the literature that satisfied the inclusion and exclusion criteria.

Results

Plasma CRP levels in women with type 2 diabetes were found to be no different from those in males with type 2 diabetes, with an OR of 0.12, 95 percent confidence interval (CI) of 0.12 to 0.12, P = 0.01. There was no statistically significant difference in the plasma level of interleukin-6 (IL-6) between women with type 2 diabetes and males with type 2 diabetes However, the “inverted funnel” diagram is asymmetrical, indicating a publication bias in the included studies, despite the fact that there was no statistically significant difference in abnormal leptin levels between men with type 2 diabetes and women patients (OR = −0.69, 95 percent CI (0.88, 1.00), P < 0.05).

Conclusion

Gender factors did not affect the level of inflammatory factors and leptin level in type 2 diabetes.

mTOR: A Potential New Target in Nonalcoholic Fatty Liver Disease

The global prevalence of nonalcoholic fatty liver disease (NAFLD) continues to rise, yet effective treatments are lacking due to the complex pathogenesis of this disease. Although recent research has provided evidence for the “multiple strikes” theory, the classic “two strikes” theory has not been overturned. Therefore, there is a crucial need to identify multiple targets in NAFLD pathogenesis for the development of diagnostic markers and targeted therapeutics. Since its discovery, the mechanistic target of rapamycin (mTOR) has been recognized as the central node of a network that regulates cell growth and development and is closely related to liver lipid metabolism and other processes. This paper will explore the mechanisms by which mTOR regulates lipid metabolism (SREBPs), insulin resistance (Foxo1, Lipin1), oxidative stress (PIG3, p53, JNK), intestinal microbiota (TLRs), autophagy, inflammation, genetic polymorphisms, and epigenetics in NAFLD. The specific influence of mTOR on NAFLD was hypothesized to be divided into micro regulation (the mechanism of mTOR’s influence on NAFLD factors) and macro mediation (the relationship between various influencing factors) to summarize the influence of mTOR on the developmental process of NAFLD, and prove the importance of mTOR as an influencing factor of NAFLD regarding multiple aspects. The effects of crosstalk between mTOR and its upstream regulators, Notch, Hedgehog, and Hippo, on the occurrence and development of NAFLD-associated hepatocellular carcinoma are also summarized. This analysis will hopefully support the development of diagnostic markers and new therapeutic targets in NAFLD.

New Insights into Non-Alcoholic Fatty Liver Disease and Coronary Artery Disease: The Liver-Heart Axis

Non-alcoholic fatty liver disease (NAFLD) represents the hepatic expression of the metabolic syndrome and is the most prevalent liver disease. NAFLD is associated with liver-related and extrahepatic morbi-mortality. Among extrahepatic complications, cardiovascular disease (CVD) is the primary cause of mortality in patients with NAFLD. The most frequent clinical expression of CVD is the coronary artery disease (CAD). Epidemiological data support a link between CAD and NAFLD, underlain by pathogenic factors, such as the exacerbation of insulin resistance, genetic phenotype, oxidative stress, atherogenic dyslipidemia, pro-inflammatory mediators, and gut microbiota. A thorough assessment of cardiovascular risk and identification of all forms of CVD, especially CAD, are needed in all patients with NAFLD regardless of their metabolic status. Therefore, this narrative review aims to examine the available data on CAD seen in patients with NAFLD, to outline the main directions undertaken by the CVD risk assessment and the multiple putative underlying mechanisms implicated in the relationship between CAD and NAFLD, and to raise awareness about this underestimated association between two major, frequent and severe diseases.

The Association of Salt Intake and Non-alcoholic Fatty Liver Disease in People With Type 2 Diabetes: A Cross-Sectional Study

Objectives

Non-alcoholic fatty liver disease (NAFLD), which has a close relationship with type 2 diabetes (T2D), is related to salt intake in the general population. In contrast, the relationship between salt intake and the presence of NAFLD in patients with T2D has not been clarified.

Methods

Salt intake (g/day) was assessed using urinary sodium excretion, and a high salt intake was defined as an intake greater than the median amount of 9.5 g/day. Hepatic steatosis index (HSI) ≥ 36 points was used to diagnosed NAFLD. Odds ratios of high salt intake to the presence of NAFLD were evaluated by logistic regression analysis.

Results

The frequency of NAFLD was 36.5% in 310 patients with T2D (66.7 ± 10.7 years old and 148 men). The patients with high salt intake had a higher body mass index (25.0 ± 4.0 vs. 23.4 ± 3.8 kg/m², p < 0.001) than those with low salt intake. HSI in patients with high salt intake was higher than that in patients with low salt intake (36.2 ± 6.2 vs. 34.3 ± 5.5 points, p = 0.005). In addition, the presence of NALFD in patients with high salt intake was higher than that in patients with low salt intake (44.5% vs. 28.4%, p = 0.005). High salt intake was associated with the prevalence of NAFLD [adjusted odds ratio, 1.76 (95% confidence interval: 1.02–3.03), p = 0.043].

Conclusion

This cross-sectional study revealed that salt intake is related to the prevalence of NAFLD in patients with T2D.

Fatty kidney: A possible future for chronic kidney disease research

BACKGROUND

Metabolic syndrome is a growing twenty-first century pandemic associated with multiple clinical comorbidities ranging from cardiovascular diseases, non-alcoholic fatty liver disease and polycystic ovary syndrome to kidney dysfunction. A novel area of research investigates the concept of fatty kidney in the pathogenesis of chronic kidney disease, especially in patients with diabetes mellitus or metabolic syndrome.

AIM

To review the most updated literature on fatty kidney and provide future research, diagnostic and therapeutic perspectives on a disease increasingly affecting the contemporary world.

MATERIALS AND METHOD

We performed an extensive literature search through three databases including Embase (Elsevier) and the Cochrane Central Register of Controlled Trials (Wiley) and PubMed/Medline Web of Science in November 2021 by using the following terms and their combinations: 'fatty kidney', 'ectopic fat', 'chronic kidney disease', 'cardiovascular event', 'cardio-metabolic risk', 'albuminuria' and 'metabolic syndrome'. Each study has been individually assessed by the authors.

RESULTS

Oxidative stress and inflammation, Klotho deficiency, endoplasmic reticulum stress, mitochondrial dysfunction and disruption of cellular energy balance appear to be the main pathophysiological mechanisms leading to tissue damage following fat accumulation. Despite the lack of large-scale comprehensive studies in this novel field of research, current clinical trials demonstrate fatty kidney as an independent risk factor for the development of chronic kidney disease and cardiovascular events.

CONCLUSION

The requirement for future studies investigating the pathophysiology, clinical outcomes and therapeutics of fatty kidney is clear.

Influence of High Energy Diet and Polygenic Predisposition for Obesity on Postpartum Health in Rat Dams

It is estimated that 30% of pregnant women worldwide are overweight or obese, leading to adverse health effects for both mother and child. Women with obesity during pregnancy are at higher risk for developing both metabolic and mental disorders, such as diabetes and depression. Numerous studies have used rodent models of maternal obesity to understand its consequences on the offspring, yet characterization of changes in the dams is rare, and most rodent models rely solely on a high fat diet to induce maternal obesity, without regarding genetic propensity for obesity. Here we present the influence of both peripartum high energy diet (HE) and obesity-proneness on maternal health using selectively bred diet-resistant (DR) and diet-induced obese (DIO) rat dams. Outbred Sprague-Dawley rats were challenged with HE diet prior to mating and bred according to their propensity to gain weight. The original outbred breeding dams (F0) were maintained on low-fat chow during pregnancy and lactation. By comparison, the F1 dams consuming HE diet during pregnancy and lactation displayed higher gestational body weight gain (P < 0.01), and HE diet caused increased meal size and reduced meal frequency (P < 0.001). Sensitivity to the hormone amylin was preserved during pregnancy, regardless of diet. After several rounds of selective breeding, DIO and DR dams from generation F3 were provided chow or HE during pregnancy and lactation and assessed for their postpartum physiology and behaviors. We observed strong diet and phenotype effects on gestational weight gain, with DIO-HE dams gaining 119% more weight than DR-chow (P < 0.001). A high-resolution analysis of maternal behaviors did not detect main effects of diet or phenotype, but a subset of DIO dams showed delayed nursing behavior (P < 0.05). In generation F6/F7 dams, effects on gestational weight gain persisted (P < 0.01), and we observed a main effect of phenotype during a sucrose preference test (P < 0.05), with DIO-chow dams showing lower sucrose preference than DR controls (P < 0.05). Both DIO and DR dams consuming HE diet had hepatic steatosis (P < 0.001) and exhibited reduced leptin sensitivity in the arcuate nucleus (P < 0.001). These data demonstrate that both diet and genetic obesity-proneness have consequences on maternal health.

Mechanism-Based Biomarker Prediction for Low-Grade Inflammation in Liver and Adipose Tissue

Metabolic disorders, such as obesity and type 2 diabetes have a large impact on global health, especially in industrialized countries. Tissue-specific chronic low-grade inflammation is a key contributor to complications in metabolic disorders. To support therapeutic approaches to these complications, it is crucial to gain a deeper understanding of the inflammatory dynamics and to monitor them on the individual level. To this end, blood-based biomarkers reflecting the tissue-specific inflammatory dynamics would be of great value. Here, we describe an in silico approach to select candidate biomarkers for tissue-specific inflammation by using a priori mechanistic knowledge from pathways and tissue-derived molecules. The workflow resulted in a list of candidate markers, in part consisting of literature confirmed biomarkers as well as a set of novel, more innovative biomarkers that reflect inflammation in the liver and adipose tissue. The first step of biomarker verification was on murine tissue gene-level by inducing hepatic inflammation and adipose tissue inflammation through a high-fat diet. Our data showed that in silico predicted hepatic markers had a strong correlation to hepatic inflammation in the absence of a relation to adipose tissue inflammation, while others had a strong correlation to adipose tissue inflammation in the absence of a relation to liver inflammation. Secondly, we evaluated the human translational value by performing a curation step in the literature using studies that describe the regulation of the markers in human, which identified 9 hepatic (such as Serum Amyloid A, Haptoglobin, and Interleukin 18 Binding Protein) and 2 adipose (Resistin and MMP-9) inflammatory biomarkers at the highest level of confirmation. Here, we identified and pre-clinically verified a set of in silico predicted biomarkers for liver and adipose tissue inflammation which can be of great value to study future development of therapeutic/lifestyle interventions to combat metabolic inflammatory complications.

NAFLD-Related Hepatocarcinoma: The Malignant Side of Metabolic Syndrome

Hepatocellular carcinoma (HCC) is the seventh most common cancer worldwide and the second leading cause of cancer-related mortality. HCC typically arises within a cirrhotic liver, but in about 20% of cases occurs in absence of cirrhosis. Among non-cirrhotic risk factors, non-alcoholic fatty liver disease (NAFLD) currently represents the most important emerging cause of HCC in developed countries. It has been estimated that annual incidence of HCC among patients with non-cirrhotic NAFLD is approximately 0.1-1.3 per 1000 patients/year and ranges from 0.5% to 2.6% among patients with non-alcoholic steatohepatitis (NASH) cirrhosis. However, only a few clinical trials enrolling HCC patients actually distinguished NAFLD/NASH-related cases from other non-cirrhotic causes and therefore evidence is still lacking in this subset of patients. This review aims to describe the biology underpinning NAFLD development, to investigate the main molecular pathways involved in its progression to NASH and HCC and to describe how different pathogenetic mechanisms underlying the onset of HCC can have an impact in clinical practice. We hereby also provide an overview of current HCC treatment options, with a particular focus on the available data on NAFLD-related cases in practice-changing clinical trials.

Role of Leptin in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD), which affects about a quarter of the global population, poses a substantial health and economic burden in all countries, yet there is no approved pharmacotherapy to treat this entity, nor well-established strategies for its diagnosis. Its prevalence has been rapidly driven by increased physical inactivity, in addition to excessive calorie intake compared to energy expenditure, affecting both adults and children. The increase in the number of cases, together with the higher morbimortality that this disease entails with respect to the general population, makes NAFLD a serious public health problem. Closely related to the development of this disease, there is a hormone derived from adipocytes, leptin, which is involved in energy homeostasis and lipid metabolism. Numerous studies have verified the relationship between persistent hyperleptinemia and the development of steatosis, fibrinogenesis and liver carcinogenesis. Therefore, further studies of the role of leptin in the NAFLD spectrum could represent an advance in the management of this set of diseases.

Body mass index and serum levels of soluble leptin receptor are sex-specifically related to alcohol binge drinking behavior

OBJECTIVE

Binge drinking is a highly prevalent behavior in adolescents and young adults and a risk factor to develop alcohol use disorder. Body mass index (BMI) and blood levels of leptin peptide and its soluble receptor have been implicated in alcohol use disorder; however, their role in binge drinking remains to be investigated.

METHOD

We studied associations of BMI, serum levels of soluble leptin receptor (ObRe) and leptin as well as the free leptin index with binge drinking in 93 male and 99 female young adults.

RESULTS

In men, binge drinkers showed significantly higher BMI (kg/m²) than non-binge drinkers (23.67 vs. 22.08) and higher BMI correlated significantly with more severe binge drinking episodes (ρ = 0.251). In women, we found significantly higher ObRe (ng/ml) / BMI (kg/m²) values in binge drinkers than in non-binge drinkers (0.52 vs. 0.44) and ObRe/BMI values correlated significantly with more severe binge drinking episodes (ρ = 0.210).

CONCLUSION

This study confirms that higher BMI associates with binge drinking in men and shows for the first time a role of ObRe/BMI in binge drinking in women. Our data emphasize the importance of further research in the field of metabolic markers and implications in neurobiological processes of binge drinking.

NAFLD in type 2 diabetes mellitus: Still many challenging questions

Epidemiologic data consistently show that in patients with type 2 diabetes (T2DM) the prevalence of non-alcoholic fatty liver disease (NAFLD), including advanced fibrosis, is double compared to the general population, and it associates with high risk of liver-related morbidity (advanced fibrosis, hepatocellular carcinoma) and mortality, but also with other systemic consequences, such as cardiovascular (CV) disease, chronic kidney disease, and overall mortality. There are still many answers that need to be clarified regarding NAFLD in T2DM, including deciphering the complex pathogenetic mechanisms, the intertwined relationships with the extrahepatic organs and tissues (mainly heart, kidneys, adipose tissue, gut), the prognostic value of NAFLD for CV risk stratification, and more importantly, what would be the most appropriate screening algorithm, diagnostic method and therapeutic approach. We advocate here for proactive action, in order to identify NAFLD in a timely manner, and suggest a simple algorithm to be used in clinical practice, based on risk stratification and on experts' opinions. We discuss the current therapeutic options for NAFLD in T2DM, for which a multifactorial approach is needed, that concomitantly addresses the liver and the cardio-reno-metabolic disturbances.

Chemerin/CMKLR1 ameliorates nonalcoholic steatohepatitis by promoting autophagy and alleviating oxidative stress through the JAK2-STAT3 pathway

Nonalcoholic steatohepatitis (NASH) is a global public health challenge. Overwhelmed oxidative stress and impaired autophagy play an important role in the progression of NASH. Chemerin is an adipokine that has attracted much attention in inflammation and metabolic diseases. This study aimed to examine the effects of chemerin in NASH and its association with oxidative stress and autophagy. In this study, chemerin was found to significantly ameliorate high-fat diet (HFD) induced NASH, marked by decreased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α), decreased insulin resistance (IR) and leptin resistance (LR), and improved liver lesions. Besides, chemerin prevented enhanced oxidative stress in NASH mice by regulating the antioxidant defense system (MDA downregulation and upregulation of superoxide dismutase (SOD)). Moreover, chemerin contributed to the alleviation of NASH through autophagy activation (p62 downregulation, and upregulation of beclin-1 and LC3). Furthermore, these effects were related to increased phosphorylation of JAK2-STAT3 stimulated by chemerin, which could be inhibited by the CMKLR1 specific inhibitor α-NETA. In conclusion, excess chemerin highly probably ameliorated NASH by alleviating oxidative stress and promoting autophagy, the mechanism responsible for this process was related, at least in part, to the increased phosphorylation of JAK2-STAT3 stimulated by chemerin/CMKLR1. Rh-chemerin may represent promising therapeutic targets in the treatment of NASH.

Comparison of dapagliflozin and teneligliptin in nonalcoholic fatty liver disease patients without type 2 diabetes mellitus: a prospective randomized study

There are no reports regarding the efficacy of sodium-glucose cotransporter 2 inhibitor (SGLT2i) and dipeptidyl peptidase 4 inhibitor (DPP4i) administrations in nonalcoholic fatty liver disease (NAFLD) patients without type 2 diabetes mellitus. The purpose of this study was to evaluate the efficacy of those drugs in such patients. NAFLD patients without type 2 diabetes mellitus were enrolled in this single center double-blind randomized prospective study, and allocated to receive either dapagliflozin (SGLT2i) or teneligliptin (DPP4i) for 12 weeks. Laboratory variables and body compositions were assessed at the baseline and end of treatment. The primary endpoint was alanine aminotransferase (ALT) reduction level at the end of treatment. Twenty-two eligible patients (dapagliflozin group, n = 12; teneligliptin group, n = 10) were analyzed. In both groups, the serum concentration of ALT was significantly decreased after treatment (p<0.05). Multiple regression analysis results showed that decreased body weight of patients with dapagliflozin administration was significantly related to changes in total body water and body fat mass. Administration of dapagliflozin or teneligliptin decreased the serum concentration of ALT in NAFLD patients without type 2 diabetes mellitus. With dapagliflozin, body weight decreased, which was related to changes in total body water and body fat mass (UMIN000027304).

In Vitro and In Vivo Models of Non-Alcoholic Fatty Liver Disease: A Critical Appraisal

Non-alcoholic fatty liver disease (NAFLD), including non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH), represents the hepatic manifestation of obesity and metabolic syndrome. Due to the spread of the obesity epidemic, NAFLD is becoming the most common chronic liver disease and one of the principal indications for liver transplantation. However, no pharmacological treatment is currently approved to prevent the outbreak of NASH, which leads to fibrosis and cirrhosis. Preclinical research is required to improve our knowledge of NAFLD physiopathology and to identify new therapeutic targets. In the present review, we summarize advances in NAFLD preclinical models from cellular models, including new bioengineered platforms, to in vivo models, with a particular focus on genetic and dietary mouse models. We aim to discuss the advantages and limits of these different models.

Parathyroid Hormone and 25-Hydroxyvitamin D Do Not Mediate the Association between Dietary Calcium, Protein and Vitamin D Intake and Adiposity and Lipid Profile in Patients with Type 2 Diabetes: a Structural Equation Modeling Approach

This study aimed to utilize structural equation modeling (SEM) techniques to determine the effects of dietary calcium, protein and vitamin D on adiposity and lipidemia and to assess mediatory effects of parathyroid hormone (PTH) and 25-hydroxyvitamin D (25(OH)D) in patients with type 2 diabetes. In this cross-sectional study, a total of 150 diabetic patients (93 females and 57 males) were randomly selected. Anthropometric measures, biochemical analyses, and fat mass percent were recorded. Nutritional data were collected. SEM was performed. Based on the primary hypothesis, adiposity and lipidemia were fitted in a model. The direct effects of dietary calcium (λ = -0.165, p value = 0.002) and PTH (λ = -0.143, p value = 0.011) were significantly associated with lipidemia. There were no significant effects for dietary protein on PTH (λ = -0.270, p value = 0.057), 25(OH)D (λ = -0.071, p value = 0.613), lipidemia (λ = -0.044; p value = 0.638) or adiposity (λ = -0.009, p value = 0.949) as well as for dietary vitamin D on PTH (λ = -0.119, p value = 0.194), 25(OH)D (λ = 0.023, p value = 0.806), lipidemia (λ = 0.034, p value = 0.587) or adiposity (λ = -0.221, p value = 0.118). The correlation between calcium intake and lipidemia, and adiposity are not mediated by 25(OH)D and PTH. There were the direct effects of dietary calcium on adiposity in patients with type 2 diabetes. The model can be tested in future longitudinal and intervention studies to identify the predictors of obesity.

Metabolic liver disease in diabetes - From mechanisms to clinical trials

Non-alcoholic fatty liver disease (NAFLD) comprises fatty liver (steatosis), non-alcoholic steatohepatitis (NASH) and fibrosis/cirrhosis and may lead to end-stage liver failure or hepatocellular carcinoma. NAFLD is tightly associated with the most frequent metabolic disorders, such as obesity, metabolic syndrome, and type 2 diabetes mellitus (T2DM). Both multisystem diseases share several common mechanisms. Alterations of tissue communications include excessive lipid and later cytokine release by dysfunctional adipose tissue, intestinal dysbiosis and ectopic fat deposition in skeletal muscle. On the hepatocellular level, this leads to insulin resistance due to abnormal lipid handling and mitochondrial function. Over time, cellular oxidative stress and activation of inflammatory pathways, again supported by multiorgan crosstalk, determine NAFLD progression. Recent studies show that particularly the severe insulin resistant diabetes (SIRD) subgroup (cluster) associates with NAFLD and its accelerated progression and increases the risk of diabetes-related cardiovascular and kidney diseases, underpinning the critical role of insulin resistance. Consequently, lifestyle modification and certain drug classes used to treat T2DM have demonstrated effectiveness for treating NAFLD, but also some novel therapeutic concepts may be beneficial for both NAFLD and T2DM. This review addresses the bidirectional relationship between mechanisms underlying T2DM and NAFLD, the relevance of novel biomarkers for improving the diagnostic modalities and the identification of subgroups at specific risk of disease progression. Also, the role of metabolism-related drugs in NAFLD is discussed in light of the recent clinical trials. Finally, this review highlights some challenges to be addressed by future studies on NAFLD in the context of T2DM.

The association of anthropometric parameters with markers of insulin and leptin secretion and resistance in type 2 diabetes mellitus

Aim: We evaluated the association between anthropometric parameters and markers of insulin and leptin secretion/resistance in patients with type 2 diabetes mellitus (T2DM).

Material and methods: This post-hoc data analysis from a cross-sectional study included 176 T2DM patients. Laboratory tests (serum leptin, soluble form of leptin receptor (sObR), C peptide, glycemic and lipid parameters) and anthropometric parameters were obtained, adiposity indexes (including body adiposity index (BAI), visceral adiposity index (VAI)), indicators of insulin resistance, β-cell function, and leptin resistance (Free Leptin Index, FLI) were calculated.

Results: The body mass index (BMI), diabetes duration, VAI and leptin correlated independently with HOMA-IR, while BMI, diabetes duration and HbA1c with HOMA-B. The total body fat mass (TBFM), C peptide, diabetes duration, BMI and BAI correlated with leptin concentrations, while the first three with FLI. VAI was an indicator of insulin resistance (β=0.166, p=0.003), while BAI of leptin secretion (β=0.260, p=0.010). TBFM strongly associated with leptin resistance and secretion (β=0.037, r=0.688, p<0.0001, and β=0.521, r=0.667, p<0.0001), and BMI correlated weakly with insulin secretion and resistance. While insulin and leptin secretion increased progressively with BMI, leptin and insulin resistance became significant only in case of obesity. The sObR was significantly associated with C peptide concentrations (β=-0.032; p=0.044), but not with HOMA-B or -IR. A strong positive correlation between the C peptide/leptin ratio and non-fat mass /TBFM ratio was noted (r=0.62 [0.52, 0.71], p<0.0001).

Conclusions: Parameters of peripheral adiposity correlated better with markers of leptin system, and those of visceral adiposity with markers of insulin secretion/resistance. The sObR correlated independently and negatively with C peptide.

Anti-Inflammatory Strategies Targeting Metaflammation in Type 2 Diabetes

One of the concepts explaining the coincidence of obesity and type 2 diabetes (T2D) is the metaflammation theory. This chronic, low-grade inflammatory state originating from metabolic cells in response to excess nutrients, contributes to the development of T2D by increasing insulin resistance in peripheral tissues (mainly in the liver, muscles, and adipose tissue) and by targeting pancreatic islets and in this way impairing insulin secretion. Given the role of this not related to infection inflammation in the development of both: insulin resistance and insulitis, anti-inflammatory strategies could be helpful not only to control T2D symptoms but also to treat its causes. This review presents current concepts regarding the role of metaflammation in the development of T2D in obese individuals as well as data concerning possible application of different anti-inflammatory strategies (including lifestyle interventions, the extra-glycemic potential of classical antidiabetic compounds, nonsteroidal anti-inflammatory drugs, immunomodulatory therapies, and bariatric surgery) in the management of T2D.

Serum lipids, leptin, and soluble leptin receptor in alcohol dependence: A cross-sectional and longitudinal study

OBJECTIVE

Alcohol dependence affects metabolic processes. Further research is needed to apply this knowledge clinically. In this study, possible differences in serum lipids and/or leptin activities between alcohol-dependent in-patients and healthy controls and possible associations with alcohol-related blood parameters and with prospective outcomes in alcohol dependence were assessed sex-specifically.

METHOD

We measured and compared (median) serum lipids (triglycerides and total, HDL, and LDL cholesterol) and leptin activities (leptin, soluble leptin receptor [ObRe], and free leptin index) in 200 (males 56.5 %) early-abstinent alcohol-dependent in-patients and 240 (males 55.4 %) healthy controls and assessed alcohol-related readmissions during a 24 -month post-inclusion period.

RESULTS

Male patients showed higher HDL cholesterol (61 versus 48 mg/dl), lower LDL/HDL ratios (2.06 versus 3.04), and lower free leptin index (0.30 versus 0.59) at study inclusion compared to healthy controls. In patients, ObRe levels were higher than in controls and decreased from inclusion to the second study-visit (at median 5 days later; males: 16.7-13.8 versus 11.0 ng/ml; females: 17.0-13.4 versus 12.1 ng/ml). The free leptin index increased between the two time points in females (0.80 versus 1.20). Lipids and leptin activities correlated with carbohydrate-deficient transferrin levels and liver enzyme activities. None of the serum parameters were significantly associated with alcohol-related readmissions.

CONCLUSION

Our data support that serum lipid levels and leptin activities are involved in alcohol dependence. The parameters appear as possible indirect biomarkers for alcohol dependence.

Synergism of Adipocytokine Profile and ADIPOQ/TNF-α Polymorphisms in NAFLD-associated MetS Predict Colorectal Liver Metastases Outgrowth

BACKGROUND/AIM

The aim of this study was to evaluate whether the altered profile of adipocytokine and genetic fingerprint in NAFLD-associated metabolic syndrome "cluster" represents synergistic risk factors predicting onset of liver colorectal cancer metastases.

MATERIALS AND METHODS

A total of 165 colorectal cancer patients were enrolled, 56,3% were with metabolic syndrome/NAFLD. Serum samples were assayed for ADIPOQ, leptin and TNF-a levels by ELISA. ADIPOQ rs266729 C/G and TNF-308 A/G genotypes were analyzed in DNA isolated from whole blood.

RESULTS

Reduction in adiponectin levels and increase in leptin and TNF-α was shown in patients with liver metastases. This trend was influenced by BMI, MetS/NAFLD, and insulin resistance. ADIPOQ G rs266729 and TNF- 308 A allele are associated with obesity, MetS/NAFLD and insulin resistance. ADIPOQ CG/GG and GA/AA TNF-alpha genotypes confer susceptibility to liver metastases.

CONCLUSION

Obesity and hepatic steatosis significantly favor the development of colorectal cancer liver metastases and the individual adipocytokines genetic profile may play an important predictive role.

Atrial Fibrillation and Heart Failure With Preserved Ejection Fraction in Patients With Nonalcoholic Fatty Liver Disease

The most common causes of chronic liver disease in the developed world-nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH)-are the hepatic manifestations of an insulin-resistant state that is linked to visceral adiposity and systemic inflammation. NAFLD and NASH lead to an expansion of epicardial adipose tissue and the release of proinflammatory adipocytokines that cause microcirculatory dysfunction and fibrosis of the adjoining myocardium, resulting in atrial fibrillation as well as heart failure with a preserved ejection fraction (HFpEF). Inflammatory changes in the left atrium lead to electroanatomical remodeling; thus, NAFLD and NASH markedly increase the risk of atrial fibrillation. Simultaneously, patients with NAFLD or NASH commonly show diastolic dysfunction or latent HFpEF. Interventions include 1) weight loss by caloric restriction, bariatric surgery, or intensive exercise, and 2) drugs that ameliorate fat-mediated inflammation in both the liver and heart (eg, statins, metformin, sodium-glucose cotransporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and pioglitazone). Patients with NAFLD or NASH commonly have an inflammation-related atrial and ventricular myopathy, which may contribute to symptoms and long-term outcomes.

C-peptide is associated with NAFLD inflammatory and fibrotic progression in type 2 diabetes

BACKGROUND

A higher prevalence of nonalcoholic steatohepatitis (NASH) and advanced stages of fibrosis was observed in type 2 diabetes. We aim to investigate whether C-peptide is associated with nonalcoholic fatty liver disease (NAFLD) progression in type 2 diabetic adults.

METHODS

A total of 4937 diabetic participants were enrolled from China in 2018. Liver steatosis was detected by ultrasound. Subjects with NAFLD were categorized into simple NAFLD and probable NASH by the concurrent presence of metabolic syndrome. NAFLD fibrosis score was used to identify patients with probable advanced fibrosis.

RESULTS

Individuals with a longer history of type 2 diabetes had a lower C-peptide level and a lower prevalence of probable NASH but a higher prevalence of advanced fibrosis. C-peptide was positively associated with simple NAFLD and probable NASH, with odds ratios (ORs) of 4.55 [95% confidence interval (CI) 3.16, 6.55] and 5.28 (95% CI 3.94, 7.09), respectively, comparing quartile 4 with quartile 1 (both p for trend <0.001). However, C-peptide quartiles were negatively associated with the probable presence of advanced fibrosis (Q4 vs. Q1, OR 0.59, 95% CI 0.36, 0.97, p for trend <0.05). A 1-SD increment of ln(C-peptide) was also significantly associated with inflammatory and fibrotic progression (OR 1.34, 95% CI 1.27, 1.41; OR 0.88, 95% CI 0.79, 0.98, respectively).

CONCLUSIONS

Significant but opposite associations between C-peptide and inflammatory and fibrotic progression of NAFLD were observed. Understanding islet hormone changes during type 2 diabetes and differentiating the stage of NAFLD may help to personalize treatment strategies for NAFLD patients with type 2 diabetes.

Changes in Serum Nesfatin-1 After Laparoscopic Sleeve Gastrectomy are Associated with Improvements in Nonalcoholic Fatty Liver Disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a serious and widespread disease worldwide. Bariatric surgery is one of the treatments for NAFLD. Nesfatin-1 is located in the brain, periphery and plasma. We studied the relationship between nesfatin-1 changes after laparoscopic sleeve gastrectomy (LSG) and NAFLD remission.

METHODS

A total of 29 patients participated in the study, which collected clinical information on the patients and indicators of liver function, hepatic steatosis score and nesfatin-1 level before and after LSG.

RESULTS

The average BMI of the patients before surgery was 42.63±8.91 kg/m², and the average BMI was 28.54±5.63 kg/m² one year after surgery (p < 0.05). One year after LSG, the total weight loss percentage (TWL%) was 32.11±7.10%. The mean value of nesfatin-1 before surgery was 3.04±0.81 ng/mL, and the mean value of nesfatin-1 was 5.52±1.55 ng/mL at one year after surgery (p < 0.05). The average preoperative hepatic steatosis index (HSI) score of the patients was 52.55±9.17, and the average postoperative HSI score was 38.84±5.82 (p < 0.05). Before LSG (p < 0.05, r= -0.81) and 1 year after surgery (p < 0.05, r = -0.58), HSI and nesfatin-1 were significantly negatively correlated. Percentage of increased nesfatin-1 and percentage of decreased HSI showed positive correlation after LSG.

CONCLUSION

There was a negative correlation between HSI and nesfatin-1 before and after LSG, which may suggest that nesfatin-1 plays a role in NAFLD.

Is "Leptin Resistance" Another Key Resistance to Manage Type 2 Diabetes?

Although novel pharmacological options for the treatment of type 2 diabetes mellitus (DM2) have been observed to modulate the functionality of several key organs in glucose homeostasis, successful regulation of insulin resistance (IR), body weight management, and pharmacological treatment of obesity remain notable problems in endocrinology. Leptin may be a pivotal player in this scenario, as an adipokine which centrally regulates appetite and energy balance. In obesity, excessive caloric intake promotes a low-grade inflammatory response, which leads to dysregulations in lipid storage and adipokine secretion. In turn, these entail alterations in leptin sensitivity, leptin transport across the blood-brain barrier and defects in post-receptor signaling. Furthermore, hypothalamic inflammation and endoplasmic reticulum stress may increase the expression of molecules which may disrupt leptin signaling. Abundant evidence has linked obesity and leptin resistance, which may precede or occur simultaneously to IR and DM2. Thus, leptin sensitivity may be a potential early therapeutic target that demands further preclinical and clinical research. Modulators of insulin sensitivity have been tested in animal models and small clinical trials with promising results, especially in combination with agents such as amylin and GLP-1 analogs, in particular, due to their central activity in the hypothalamus.

Brain leptin reduces liver lipids by increasing hepatic triglyceride secretion and lowering lipogenesis

Hepatic steatosis develops when lipid influx and production exceed the liver’s ability to utilize/export triglycerides. Obesity promotes steatosis and is characterized by leptin resistance. A role of leptin in hepatic lipid handling is highlighted by the observation that recombinant leptin reverses steatosis of hypoleptinemic patients with lipodystrophy by an unknown mechanism. Since leptin mainly functions via CNS signaling, we here examine in rats whether leptin regulates hepatic lipid flux via the brain in a series of stereotaxic infusion experiments. We demonstrate that brain leptin protects from steatosis by promoting hepatic triglyceride export and decreasing de novo lipogenesis independently of caloric intake. Leptin’s anti-steatotic effects are generated in the dorsal vagal complex, require hepatic vagal innervation, and are preserved in high-fat-diet-fed rats when the blood brain barrier is bypassed. Thus, CNS leptin protects from ectopic lipid accumulation via a brain-vagus-liver axis and may be a therapeutic strategy to ameliorate obesity-related steatosis.

Obesity is associated with leptin resistance and rising blood leptin levels while central leptin exposure may be limited. Here, the authors show that brain leptin infusion reduces hepatic lipid content in rats by increasing hepatic VLDL secretion and lowering liver de novo lipogenesis via a vagal mechanism.

Environmental microcystin targets the microbiome and increases the risk of intestinal inflammatory pathology via NOX2 in underlying murine model of Nonalcoholic Fatty Liver Disease

With increased climate change pressures likely to influence harmful algal blooms, exposure to microcystin, a known hepatotoxin and a byproduct of cyanobacterial blooms can be a risk factor for NAFLD associated comorbidities. Using both in vivo and in vitro experiments we show that microcystin exposure in NAFLD mice cause rapid alteration of gut microbiome, rise in bacterial genus known for mediating gut inflammation and lactate production. Changes in the microbiome were strongly associated with inflammatory pathology in the intestine, gut leaching, tight junction protein alterations and increased oxidative tyrosyl radicals. Increased lactate producing bacteria from the altered microbiome was associated with increased NOX-2, an NADPH oxidase isoform. Activationof NOX2 caused inflammasome activation as shown by NLRP3/ASCII and NLRP3/Casp-1 colocalizations in these cells while use of mice lacking a crucial NOX2 component attenuated inflammatory pathology and redox changes. Mechanistically, NOX2 mediated peroxynitrite species were primary to inflammasome activation and release of inflammatory mediators. Thus, in conclusion, microcystin exposure in NAFLD could significantly alter intestinal pathology especially by the effects on microbiome and resultant redox status thus advancing our understanding of the co-existence of NAFLD-linked inflammatory bowel disease phenotypes in the clinic.

Leptin-deficient mice have altered three-dimensional growth plate histomorphometry

BACKGROUND

Leptin is an adipokine that regulates energy homeostasis and is also needed for normal bone growth and maintenance. Mutation in the lep gene, which characterizes the ob/ob mouse model, results in the development of obesity and type 2 diabetes mellitus, as well as reduced limb bone length and increased fracture risk. However, the relationship between limb bone length and growth plate cartilage structure in obese diabetic adolescents is incompletely understood. Here, we tested the hypothesis that leptin deficiency affects the microstructure of growth plate cartilage in juvenile ob/ob mice.

METHODS

Tibial growth plate cartilage structure was compared between lean and obese, leptin-deficient (ob/ob) female mice aged 10 weeks. We used confocal laser scanning microscopy to assess 3D histological differences in Z stacks of growth plate cartilage at 0.2 µm intervals, 80-100 µm in depth. Histomorphometric comparisons were made between juvenile lean and ob/ob mice.

RESULTS

We found obese mice have significantly reduced tibial length and growth plate height in comparison with lean mice (P < 0.05). Obese mice also have fewer chondrocyte columns in growth plate cartilage with reduced chondrocyte cell volumes relative to lean mice (P < 0.05).

CONCLUSIONS

These data help explicate the relationship between growth plate cartilage structure and bone health in obese diabetic juvenile mice. Our findings suggest obesity and diabetes may adversely affect growth plate cartilage structure.

Malnutrition and Metabolic Changes in Patients with Type 2 Diabetes

Background/Aim: In patients with type 2 diabetes (T2D), malnutrition has been recognized as a serious health problem mainly in hospitalized conditions, but there is little data regarding malnutrition outside hospital settings. The aim of this study was to evaluate the risk of malnutrition and associated metabolic changes in ambulatory patients with T2D.

Material and methods: This analysis used data collected from 161 patients with T2D enrolled in a larger cross-sectional study. Several anthropometric and metabolic parameters were obtained. Nutritional status was evaluated using the Controlling Nutritional Status (CONUT) score. Correlations between nutritional status and metabolic and anthropometric parameters of interest were examined.

Results: Of all T2D patients, 29.8% had mild malnutrition (CONUT score 2–4). These patients presented lower triglyceride (124.8 ± 42.3 mg/dL vs. 165.7 ± 84.3 mg/dL, p <0.01) and LDL cholesterol concentrations (62.7 ± 20.0 mg/dL vs. 104.9 ± 30.6 mg/dL, p <0.0001), higher leptin levels (10.2 [1.6–44.9] ng/mL vs. 7.3 [0.9–49.8] ng/mL, p <0.05) and free leptin index (0.65 [0.04–2.88] vs. 0.36 [0.01–3.98], p <0.05) compared with patients with normal nutritional status. They also had higher total body adiposity. In patients with obesity, triglycerides levels were lower in those with mild malnutrition vs. those without malnutrition (mean difference: 27.26 mg/dL, p <0.05). Serum C peptide/leptin ratio was higher in T2D patients with normal nutritional status without obesity, the differences being significant vs. the two groups with obesity (with or without malnutrition, 0.71 ± 0.53, 0.42 ± 0.33, and 0.49 ± 0.68, respectively). HOMA-IR was lower in patients with normal nutritional status without obesity vs. those with obesity (mean difference: −0.7126, p <0.05), while in patients with mild malnutrition, HOMA-IR values were higher, but no differences were noted between the groups with or without obesity.

Conclusion: In patients with T2D, malnutrition associated with lower triglycerides concentrations, even in the presence of obesity. Malnutrition and/or obesity associated with higher HOMA-IR, serum leptin levels and lower C peptide/leptin ratio.