Lipid overload and overflow: metabolic trauma and the metabolic syndrome

Waistline to thigh circumference ratio as a predictor of MAFLD: a health care worker study with 2-year follow-up

BACKGROUND

This study aimed to determine whether the waist-to-thigh ratio (WTTR) is associated with the incidence of metabolic-associated fatty liver disease (MAFLD) in health care workers.

METHODS

There were 4517 health care workers with baseline data and results from 2 follow-up examinations. We divided the subjects into 3 groups according to baseline WTTR and used the Cox hazard regression model to estimate MAFLD risk.

RESULTS

The WTTRs were categorized by tertiles at baseline using the values 1.58 and 1.66. Patients with higher WTTR tended to have significantly greater values for the following factors, body mass index (BMI), fasting blood glucose (FPG), systolic blood pressure, diastolic blood pressure, total cholesterol (TC), triglycerides (TG), low-density lipoprotein-cholesterol (LDL-C) and neck circumference. The incidence of MAFLD significantly increased with increasing WTTR tertiles (5.74%, 12.75% and 22.25% for the first, second and third tertiles, respectively, P < 0.05 for trend). Kaplan-Meier(K-M) survival analysis revealed a significant tendency towards increased MAFLD risk with increasing WTTR tertile. In the fully adjusted model, the hazard ratios (95% CIs) for MAFLD in the second, third WTTR tertiles compared with the first quartile were 2.17(1.58,2.98), 3.63(2.70,4.89), respectively, third neck circumference tertiles compared with the first quartile were 2.84(1.89,4.25), 8.95(6.00,13.35), respectively. Compared with those of individuals with a BMI > 23 kg/m2, the associations between WTTR and MAFLD incidence were more pronounced in subjects with a BMI < 23 kg/m2. Similarly, the difference in neck circumference was more pronounced in these patients with a BMI < 23 kg/m2.

CONCLUSIONS

Our results revealed that the WTTR is an independent risk factor for MAFLD, and there was a dose‒response relationship between the WTTR and MAFLD risk. The neck circumference was significantly different in subjects with a BMI < 23 kg/m2. This approach provides a new way to predict the incidence rate of MAFLD.

Association of the fat mass index with hepatic steatosis and fibrosis: evidence from NHANES 2017-2018

Limited population-based studies discuss the association between fat mass index (FMI) and the risk of liver diseases. This investigation utilized data from the National Health and Nutrition Examination Survey (NHANES) to examine the linkage between the FMI and liver conditions, specifically steatosis and fibrosis. The study leveraged data from NHANES's 2017-2018 cross-sectional study, employing an oversampling technique to deal with sample imbalance. Hepatic steatosis and fibrosis were identified by vibration-controlled transient elastography. Receiver operating curve was used to assess the relationship of anthropometric indicators, e.g., the FMI, body mass index (BMI), weight-adjusted-waist index (WWI), percentage of body fat (BF%), waist-to-hip ratio (WHR), and appendicular skeletal muscle index (ASMI), with hepatic steatosis and fibrosis. In this study, which included 2260 participants, multivariate logistic regression models, stratified analyses, restricted cubic spline (RCS), and sharp regression discontinuity analyses were utilized. The results indicated that the WHR and the FMI achieved the highest area under the curve for identifying hepatic steatosis and fibrosis, respectively (0.720 and 0.726). Notably, the FMI presented the highest adjusted odds ratio for both hepatic steatosis (6.40 [4.91-8.38], p = 2.34e-42) and fibrosis (6.06 [5.00, 7.37], p = 5.88e-74). Additionally, potential interaction effects were observed between the FMI and variables such as the family income-to-poverty ratio, smoking status, and hypertension, all of which correlated with the presence of liver fibrosis (p for interaction < 0.05). The RCS models further confirmed a significant positive correlation of the FMI with the controlled attenuation parameter and liver stiffness measurements. Overall, the findings underscore the strong link between the FMI and liver conditions, proposing the FMI as a potential straightforward marker for identifying liver diseases.

Structural modifications of INGAP-PP present in HTD4010 peptide potentiate its effect on rat islet gene expression and insulin secretion

Type 2 diabetes (T2D) is characterized by peripheral insulin resistance and altered insulin secretion due to a progressive loss of β-cell mass and function. Today, most antidiabetic agents are designed to resolve impaired insulin secretion and/or insulin resistance, and only GLP-1-based formulations contribute to stopping the decline in β-cell mass. HTD4010, a peptide carrying two modifications of the amino acid sequence of INGAP-PP (N-terminus acetylation and substitution of Asn13 by Ala) showed greater plasma stability and could be a good candidate for proposal as a drug that could improve β cell mass and function lost in T2D. In the present study, we showed that HTD4010 included in the culture media of normal rat islets at a dose 100 times lower than that used for INGAP-PP was able to modulate, in the same way as the original peptide, both insulin secretion in response to glucose and the expression of key genes related to insular function, insulin and leptin intracellular pathways, neogenesis, apoptosis, and inflammatory response. Our results confirm the positive effect of HTD4010 on β-cell function and gene expression of factors involved in the maintenance of β-cell mass. Although new assays in animal models of prediabetes and T2D must be performed to be conclusive, our results are very encouraging, and they suggest that the use of HTD4010 at a dose 100 times lower than that of INGAP-PP could minimize its side effects in a future clinical trial.

Cellular mechanism of diabetes remission by bariatric surgery

Bariatric surgery is a powerful therapy for type 2 diabetes in patients with obesity. The mechanism of insulin sensitization by surgery has been extensively investigated in weight loss-dependent and weight loss-independent conditions. However, a consensus remains to be established regarding the underlying mechanisms. Energy deficit induced by calorie restriction (CR), that occurs both before and after surgery, represents a unique physiological basis for insulin sensitization regardless of weight loss. In support, we integrate evidence in the literature to provide an energy-based view of insulin sensitization as follows: surgery improves insulin sensitivity through the energy deficit induced by CR, leading to correction of mitochondrial overload in multiple cell types; this then triggers functional reprogramming of relevant tissues leading to diabetes remission.

Circulatory miRNAs as Correlates of Elevated Intra-Pancreatic Fat Deposition in a Mixed Ethnic Female Cohort: The TOFI_Asia Study

Ectopic lipid accumulation, including intra-pancreatic fat deposition (IPFD), exacerbates type 2 diabetes risk in susceptible individuals. Dysregulated circulating microRNAs (miRNAs) have been identified as correlating with clinical measures of pancreatitis, pancreatic cancer and type 1 diabetes. The aim of the current study was therefore to examine the association between circulating abundances of candidate miRNAs, IPFD and liver fat deposition as quantified using magnetic resonance imaging (MRI) and spectroscopy (MRS). Asian Chinese (n = 34; BMI = 26.7 ± 4.2 kg/m2) and European Caucasian (n = 34; BMI = 28.0 ± 4.5 kg/m2) females from the TOFI_Asia cohort underwent MRI and MRS analysis of pancreas (MR-%IPFD) and liver fat (MR-%liver fat), respectively, to quantify ectopic lipid deposition. Plasma miRNA abundances of a subset of circulatory miRNAs associated with IPFD and liver fat deposition were quantified by qRT-PCR. miR-21-3p and miR-320a-5p correlated with MR-%IPFD, plasma insulin and HOMA2-IR, but not MR-%liver fat. MR-%IPFD remained associated with decreasing miR-21-3p abundance following multivariate regression analysis. miR-21-3p and miR-320a were demonstrated to be negatively correlated with MR-%IPFD, independent of ethnicity. For miR-21-3p, this relationship persists with the inclusion of MR-%liver fat in the model, suggesting the potential for a wider application as a specific circulatory correlate of IPFD.

Analysis of risk factors related to nonalcoholic fatty liver disease: a retrospective study based on 31,718 adult Chinese individuals

Objective

Nonalcoholic fatty liver disease (NAFLD) is becoming increasingly prevalent worldwide. This study guides the prevention and diagnosis of NAFLD by analyzing its risk factors and the diagnostic value of each index for NAFLD.

Method

We collected the clinical information of adults individuals who underwent physical examination in the Physical Examination Center of Qingpu Branch of Zhongshan Hospital, Fudan University, from January 2016 to January 2020, including gender, age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), and low-density lipoprotein (LDL). We performed logistic regression analysis and ROC diagnostic analysis.

Results

The results showed that age, BMI, SBP, ALT, AST, FBG, TBIL, TG, and LDL were risk factors for NAFLD in adults, and HDL was a protective factor (all p-values were less than 0.05). Among them, age, BMI, ALT, TG, and HDL had a predictive value for the occurrence of NAFLD in the adults (AUC = 0.708, 0.836, 0.767, 0.780, and 0.732, respectively). The combination of age, BMI, ALT, TG, and HDL had a diagnostic value for the occurrence of NAFLD (AUC = 0.881).

Conclusion

Healthy people should pay attention to their BMI levels, manage blood pressure, blood glucose, and lipid levels, and pay attention to changes in ALT and AST index levels to prevent NAFLD. Age, BMI, ALT, TG, and HDL indexes are helpful factors in the diagnosis of NAFLD.

Obesity-induced metabolic imbalance allosterically modulates CtBP2 to inhibit PPAR-alpha transcriptional activity

Maintenance of metabolic homeostasis is secured by metabolite-sensing systems, which can be overwhelmed by constant macronutrient surplus in obesity. Not only the uptake processes but also the consumption of energy substrates determine the cellular metabolic burden. We herein describe a novel transcriptional system in this context comprised of peroxisome proliferator-activated receptor alpha (PPARα), a master regulator for fatty acid oxidation, and C-terminal binding protein 2 (CtBP2), a metabolite-sensing transcriptional co-repressor. CtBP2 interacts with PPARα to repress its activity, and the interaction is enhanced upon binding to malonyl-CoA, a metabolic intermediate increased in tissues in obesity and reported to suppress fatty acid oxidation through inhibition of carnitine palmitoyltransferase 1 (CPT1). In line with our preceding observations that CtBP2 adopts a monomeric configuration upon binding to acyl-CoAs, we determined that mutations in CtBP2 that shift the conformational equilibrium toward monomers increase the interaction between CtBP2 and PPARα. In contrast, metabolic manipulations that reduce malonyl-CoA decreased the formation of the CtBP2/PPARα complex. Consistent with these in vitro findings, we found that the CtBP2/PPARα interaction is accelerated in obese livers while genetic deletion of CtBP2 in the liver causes derepression of PPARα target genes. These findings support our model where CtBP2 exists primarily as a monomer in the metabolic milieu of obesity to repress PPARα, representing a liability in metabolic diseases that can be exploited to develop therapeutic approaches.

Association of triglyceride-glucose index with incident hypertension among non-overweight healthy adults: A cohort study in China

BACKGROUND AND AIMS

Overweight and obesity are well recognized as important and traditional risk factors for hypertension (HTN), but the prevalence of HTN tends to increase in non-overweight people. Triglyceride-glucose (TyG) index has been observed to be associated with HTN. However, whether such association still persists in non-overweight people remains unclear. The aim of our cohort study was to explore the link between TyG index and incident HTN in non-overweight Chinese population.

METHODS AND RESULTS

As many as 4678 individuals without HTN at baseline were involved, who underwent at least two years of health check-ups in the eight-year study period and maintained non-overweight at follow-up. According to baseline TyG index quintiles, participants were classified into five groups. Compared with the 1st quantile, those in the 5th quantile of TyG index had a 1.73-fold (HR 95% CI 1.13-2.65) risk of incident HTN. The results remained consistent when analyses were restricted to participants without abnormal TG or FPG level at baseline (HR 1.62, 95% CI 1.17-2.26). Furthermore, the subgroup analyses were conducted, the risk of incident HTN was still significantly increased with increasing TyG index for subgroups of older participants (age≥ 40 years), males, females and higher BMI group (BMI≥ 21 kg/m²).

CONCLUSIONS

The risk of incident HTN increased with increasing TyG index among Chinese non-overweight adults, so TyG index might be a reliable predictor of incident HTN among adults maintaining non-overweight.

Visceral fat correlates with insulin secretion and sensitivity independent of BMI and subcutaneous fat in Chinese with type 2 diabetes

AIM

Clinical heterogeneity exists in overall obesity and abdominal obesity in terms of insulin secretion and sensitivity. Further, the impact of visceral fat (VF) on the first- and second-phase insulin secretion (FPIS and SPIS) is controversial. We aim to investigate insulin secretion and sensitivity in Chinese patients with T2DM according to different BMI and VF levels.

METHODS

This study enrolled 300 participants. A dual bioelectrical impedance analyzer was used to assess the visceral and subcutaneous fat area (VFA and SFA). VF levels were categorized as normal or high, with the cutoff value of 100 cm². FPIS and SPIS were evaluated by arginine stimulation test and standardized steamed bread meal tolerance test, respectively. β-cell function (HOMA2-β), insulin resistance (HOMA2-IR), and Gutt's insulin sensitivity index (Gutt-ISI) were also calculated. Spearman's correlation analysis and multivariate linear regression analysis were adopted for statistical analysis.

RESULTS

Participants were categorized into four groups: normal weight-normal VF, normal weight-high VF, overweight/obese-normal VF and overweight/obese-high VF. Multivariate linear regression showed that both VFA and SFA were correlated with FPIS, HOMA2-IR and Gutt-ISI after controlling for gender and diabetes duration. After further adjustment for BMI and VFA, some associations of SFA with insulin secretion and sensitivity disappeared. After adjustment for gender, diabetes duration, BMI and SFA, VFA was positively correlated with FPIS, SPIS and HOMA2-IR. Subjects with overweight/obese-high VF were more likely to have higher FPIS, HOMA2-IR and lower Gutt-ISI (all p < 0.05).

CONCLUSION

VF affects both FPIS and SPIS, and worsens insulin sensitivity independent of BMI and subcutaneous fat in Chinese patients with T2DM.

CLINICAL TRIAL REGISTRATION

http://www.chictr.org.cn, identifier ChiCTR2200062884.

Low 25 Hydroxyvitamin D and High Leptin Level as Risk Factors of Metabolic Syndrome in Obese Women

Obesity is associated with low vitamin D levels and high leptin levels. The aim of this study is to see if low vitamin D levels and high leptin levels are risk factors for metabolic syndrome in obese women.This study use case control study to observe the difference of leptin and vitamin D plasma level as risk factor of metabolic syndrome on obesity women. There are 34 obese women as the sample of study. Subject is divided randomly into 2 groups, where each of groups consists of 17 obese with syndrome metabolic case and 17 obese women as control. Each group was tested for its vitamin D and leptin level. The relationship between vitamin D and leptin levels and metabolic syndrome was then investigated using the Chi Square test, and logistic regression was taken to discover odds ratio (OR). The result is p=0.031 (p<0.05), and OR=5.25; CI 95% which means the group with low vitamin D has risk factors for metabolic syndrome by 5 times than the control group high vitamin D. It was obtained p=0.001 (p<0.05), and OR= 256; CI 95% means that the case group with high leptin is the risk factors of the occurred metabolic syndrome by 256 times than low level of leptin in control group. It is concluded that in this study there is a link between low vitamin D levels and high leptin levels as risk factors of metabolic syndrome found in obesity.

Association of METS-IR with incident hypertension in non-overweight adults based on a cohort study in Northeastern China

BACKGROUND

Insulin resistance (IR) plays an important role in the progression of hypertension (HTN); therefore, early identification of IR is clinically important for preventing HTN. Our study aims to explore the relationship between the metabolic score for IR (METS-IR) and HTN in Chinese population who maintained non-overweight.

METHODS

A total of 4678 adults who underwent annual health check-up in our institution from 2010 to 2017, did not have HTN at the first check-up and maintained non-overweight at follow-up were selected as subjects. The baseline METS-IR was calculated and the outcome was incident HTN. Cox proportional hazards regression models were used to evaluate hazards ratios of HTN for METS-IR. Additionally, sensitive analyses and stratification analyses were used to deeply verify the relationship of METS-IR with HTN. The dose-response association between METS-IR and HTN risk was investigated using restricted the cubic spline analysis fitted for the Cox proportional hazards model.

RESULTS

Compared with the first quartiles of METS-IR, the risk of incident HTN was increased by 58% [hazard ratio (HR) 1.58, 95% confidence interval (CI) 1.12-2.22] and 96% (HR 1.96, 95% CI 1.40-2.76) in the Q3 group and the Q4 group, respectively. The results remained consistent when analyses were restricted to people without abnormal high-density lipoprotein cholesterol, triglyceride or fasting plasma glucose level at baseline. A linear dose-response relationship between METS-IR and HTN risk was identified (HR 1.08, 95% CI 1.04-1.12).

CONCLUSIONS

The risk of incident HTN was associated with elevated METS-IR levels in non-overweight individuals. METS-IR could help predict the risk of HTN in non-overweight individuals.

A Review of free fatty acid-induced cell signaling, angiopoietin-like protein 4, and skeletal muscle differentiation

Postnatal skeletal muscle differentiation from quiescent satellite cells is a highly regulated process, although our understanding of the contribution of nutritional factors in myogenesis is limited. Free fatty acids (FFAs) are known to cause detrimental effects to differentiated skeletal muscle cells by increasing oxidative stress which leads to muscle wasting and insulin resistance in skeletal muscle. In addition, FFAs are thought to act as inhibitors of skeletal muscle differentiation. However, the precise molecular mechanisms underlying the effects of FFAs on skeletal muscle differentiation remains to be elucidated. There is a clear relationship between dietary FFAs and their ability to suppress myogenesis and we propose the hypothesis that the FFA-mediated increase in angiopoietin-like protein 4 (ANGPTL4) may play a role in the inhibition of differentiation. This review discusses the role of FFAs in skeletal muscle differentiation to-date and proposes potential mechanisms of FFA-induced ANGPTL4 mediated inhibition of skeletal muscle differentiation.

Sex-related association of nonalcoholic fatty liver disease and liver fibrosis with body fat distribution in the general US population

BACKGROUND

Few population-based studies have investigated the association between body fat distribution and the risk of nonalcoholic fatty liver disease (NAFLD) and significant liver fibrosis.

OBJECTIVES

We aimed to evaluate the relations of total body fat and body fat distribution with NAFLD in the general US population.

METHODS

This is a cross-sectional, population-based study based on the 2017-2018 cycle of the NHANES. Participants aged 18-59 y without known liver conditions or significant alcohol consumption were studied by DXA and vibration-controlled transient elastography to assess body composition and liver steatosis and fibrosis, respectively. Multivariable logistic regression analysis was performed to evaluate the contribution of BMI and android:gynoid ratio (A:G ratio) to the prevalence of liver steatosis and fibrosis in males and females.

RESULTS

Weighted prevalence of steatosis was 41.5% and 29.9% among the 1115 males and 1113 females included in the study, respectively, whereas 7.0% of males and 4.0% of females had elastographic evidence of significant liver fibrosis. After adjustment for age, race-Hispanic origin, diabetes, cigarette smoke, and BMI, a higher A:G ratio was associated with increased odds of steatosis in both males (OR: 1.79; 95% CI: 1.07, 2.99; P = 0.029) and females (OR: 1.95; 95% CI: 1.11, 3.41; P = 0.023). Conversely, a significant association between A:G ratio and liver fibrosis was identified in females (OR: 2.09; 95% CI: 1.11, 3.97; P = 0.026), but not in males (OR: 0.56; 95% CI: 0.29, 1.08; P = 0.078).

CONCLUSIONS

Independently from BMI, an android fat deposition pattern is associated with increased prevalence of NAFLD in both sexes, whereas the effect on fibrosis was only evident in females.

Upregulation of the serine palmitoyltransferase subunit SPTLC2 by endoplasmic reticulum stress inhibits the hepatic insulin response

Endoplasmic reticulum (ER) stress is induced by various conditions, such as inflammation and the presence of excess nutrients. Abnormal accumulation of unfolded proteins leads to the activation of a collective signaling cascade, termed the unfolded protein response (UPR). ER stress is reported to perturb hepatic insulin response metabolism while promoting insulin resistance. Here, we report that ER stress regulates the de novo biosynthesis of sphingolipids via the activation of serine palmitoyltransferase (SPT), a rate-limiting enzyme involved in the de novo biosynthesis of ceramides. We found that the expression levels of Sptlc1 and Sptlc2, the major SPT subunits, were upregulated and that the cellular concentrations of ceramide and dihydroceramide were elevated by acute ER stress inducers in primary hepatocytes and HepG2 cells. Sptlc2 was upregulated and ceramide levels were elevated by tunicamycin in the livers of C57BL/6J wild-type mice. Analysis of the Sptlc2 promoter demonstrated that the transcriptional activation of Sptlc2 was mediated by the spliced form of X-box binding protein 1 (sXBP1). Liver-specific Sptlc2 transgenic mice exhibited increased ceramide levels in the liver and elevated fasting glucose levels. The insulin response was reduced by the inhibition of the phosphorylation of insulin receptor β (IRβ). Collectively, these results demonstrate that ER stress induces activation of the de novo biosynthesis of ceramide and contributes to the progression of hepatic insulin resistance via the reduced phosphorylation of IRβ in hepatocytes.

A lipid molecule called ceramide is key to regulating the body’s insulin response, which controls blood sugar, and thus may hold keys to new treatments for metabolic diseases such as diabetes. Although ceramide levels were known to be raised in obesity and diabetes, the mechanism remained unclear. Tae-Sik Park at Gachon University, Sungnam, South Korea, and Sang-Ho Kwon at Augusta University, USA, and co-workers investigated how excess ceramide production is triggered and the blood sugar regulation consequences. They found that the liver-specific SPTLC2 transgenic mice fed a high-fat diet had increased levels of an enzyme activity of serine palmitoyltransferase which led to synthesis of high levels of ceramide in the liver. The high ceramide levels suppressed insulin signaling, imbalancing blood sugar levels and causing liver toxicity. Therapies that inhibit ceramide synthesis show promise for treatment of metabolic diseases.

Pancreatic fat infiltration, β-cell function and insulin resistance: A study of the young patients with obesity

OBJECTIVE

This study aimed to investigate the relationship between pancreatic fat infiltration (PFI) and glucose metabolism disorder, β-cell function and insulin resistance in patients with obesity.

METHODS

Pancreatic fat fraction (PFF) was quantified by MRI IDEAL-IQ technique. PFF greater than 6.2 % was defined as PFI, and 34 obese patients were divided into PFI and non-PFI groups. The 5-point plasma glucose and insulin values during oral glucose tolerance test (OGTT) were recorded. OGTT-derived indices of insulin resistance and β-cell function were calculated.

RESULTS

Glucose values levels at 0-120 min during OGTT were significantly higher and β-cell function variables were lower in PFI group than non-PFI group. While indices of insulin resistance were not significantly different between two groups. Correlation analysis showed that PFF was positively correlated with glucose levels at 0, 30 and 60 min, negatively correlated with β-cell function variables and not significantly correlated with indices of insulin resistance. However, these associations of PFF with β-cell function and glucose levels were only present in type 2 diabetes mellitus (T2DM) group but not in non-T2DM group.

CONCLUSION

There is an association between PFI and impaired β-cell function, and increased pancreatic fat may be a potential risk factor for the development of T2DM.

Adiponectin receptor agonist ameliorates cardiac lipotoxicity via enhancing ceramide metabolism in type 2 diabetic mice

Accumulation of lipids and their metabolites induces lipotoxicity in diabetic cardiomyopathy. Lowering ceramide concentration could reduce the impact of metabolic damage to target organs. Adiponectin improves lipotoxicity through its receptors (AdiopRs), which have sequence homology with ceramidase enzymes. Therefore, cardioprotective role of AdipoR agonism by AdipoRon was investigated. Sixteen-week-old male db/m and db/db mice were fed a diet containing AdipoRon for four weeks. Phenotypic and metabolic profiles with associated cellular signaling pathways involved in lipid metabolism were investigated in the mice heart and human cardiomyocytes to establish treatment effect of AdipoRon. AdipoRon ameliorated insulin resistance, fibrosis, M1-dominant inflammation, and apoptosis in association with reduced accumulations of free fatty acid, triglycerides, and TLR4-related ceramide in the heart. This resulted in overall reduction in the level of oxidative stress which ameliorated cardiac hypertrophy and its function. AdipoRon increased the expression of AdipoR1 and AdipoR2 via pAMPK/FoxO1-induced Akt phosphorylation resulting from a decrease in PP2A level. It also increased acid ceramidase activity which reduced ceramide and increased sphingosine-1 phosphate levels in the heart of db/db mice and cultured human cardiomyocytes. Consistent upregulation of AdipoRs and their downstream regulatory pathways involving pAMPK/PPARα/PGC-1α levels led to lipid metabolism enhancement, thereby improving lipotoxicity-induced peroxisome biogenesis and oxidative stress. AdipoRon might control oxidative stress, inflammation, and apoptosis in the heart through increased AdipoR expression, acid ceramidase activity, and activation of AMPK-PPARα/PGC-1α and related downstream pathways, collectively improving cardiac lipid metabolism, hypertrophy, and functional parameters.

Renal Cell Cancer and Obesity

Cancers are a frequent cause of morbidity and mortality. There are many risk factors for tumours, including advanced age, personal or family history of cancer, some types of viral infections, exposure to radiation and some chemicals, smoking and alcohol consumption, as well as obesity. Increasing evidence suggest the role of obesity in the initiation and progression of various cancers, including renal cell carcinoma. Since tumours require energy for their uncontrollable growth, it appears plausible that their initiation and development is associated with the dysregulation of cells metabolism. Thus, any state characterised by an intake of excessive energy and nutrients may favour the development of various cancers. There are many factors that promote the development of renal cell carcinoma, including hypoxia, inflammation, insulin resistance, excessive adipose tissue and adipokines and others. There are also many obesity-related alterations in genes expression, including DNA methylation, single nucleotide polymorphisms, histone modification and miRNAs that can promote renal carcinogenesis. This review focuses on the impact of obesity on the risk of renal cancers development, their aggressiveness and patients’ survival.

Supplementation of Enriched Polyunsaturated Fatty Acids and CLA Cheese on High Fat Diet: Effects on Lipid Metabolism and Fat Profile

Epidemiological studies have demonstrated a positive relationship between dietary fat intake and the onset of several metabolic diseases. This association is particularly evident in a diet rich in saturated fatty acids, typical of animal foods, such as dairy products. However, these foods are the main source of fatty acids with a proven nutraceutical effect, such as the ω-3 fatty acid α-linolenic acid (ALA) and the conjugated linoleic acid (CLA), which have demonstrated important roles in the prevention of various diseases. In the present study, the effect of a supplementation with cheese enriched with ω-3 fatty acids and CLA on the metabolism and lipid profiles of C57bl/6 mice was evaluated. In particular, the analyses were conducted on different tissues, such as liver, muscle, adipose tissue and brain, known for their susceptibility to the effects of dietary fats. Supplementing cheese enriched in CLA and ω-3 fats reduced the level of saturated fat and increased the content of CLA and ALA in all tissues considered, except for the brain. Furthermore, the consumption of this cheese resulted in a tissue-specific response in the expression levels of genes involved in lipid and mitochondrial metabolism. As regards genes involved in the inflammatory response, the consumption of enriched cheese resulted in a reduction in the expression of inflammatory genes in all tissues analyzed. Considering the effects that chronic inflammation associated with a high-calorie and high-fat diet (meta-inflammation) or aging (inflammaging) has on the onset of chronic degenerative diseases, these data could be of great interest as they indicate the feasibility of modulating inflammation (thus avoiding/delaying these pathologies) with a nutritional and non-pharmacological intervention.

Mechanisms of Kaempferol in the treatment of diabetes: A comprehensive and latest review

Obesity-insulin resistance-β-cells apoptosis" is an important trilogy of the pathogenesis of type 2 diabetes. With the global pandemic of obesity and diabetes, continuous research and development of new drugs focuses on the prevention of the pathological progress of these diseases. According to a recent study, the natural product kaempferol has excellent antidiabetic effects. Therefore, this review comprehensively summarized the frontier studies and pharmacological mechanisms of kaempferol in the treatment of diabetes. The successful research and development of kaempferol may yield a significant leap in the treatment of diabetes and its complications.

Key signaling networks are dysregulated in patients with the adipose tissue disorder, lipedema

Objectives

Lipedema, a poorly understood chronic disease of adipose hyper-deposition, is often mistaken for obesity and causes significant impairment to mobility and quality-of-life. To identify molecular mechanisms underpinning lipedema, we employed comprehensive omics-based comparative analyses of whole tissue, adipocyte precursors (adipose-derived stem cells (ADSCs)), and adipocytes from patients with or without lipedema.

Methods

We compared whole-tissues, ADSCs, and adipocytes from body mass index–matched lipedema (n = 14) and unaffected (n = 10) patients using comprehensive global lipidomic and metabolomic analyses, transcriptional profiling, and functional assays.

Results

Transcriptional profiling revealed >4400 significant differences in lipedema tissue, with altered levels of mRNAs involved in critical signaling and cell function-regulating pathways (e.g., lipid metabolism and cell-cycle/proliferation). Functional assays showed accelerated ADSC proliferation and differentiation in lipedema. Profiling lipedema adipocytes revealed >900 changes in lipid composition and >600 differentially altered metabolites. Transcriptional profiling of lipedema ADSCs and non-lipedema ADSCs revealed significant differential expression of >3400 genes including some involved in extracellular matrix and cell-cycle/proliferation signaling pathways. One upregulated gene in lipedema ADSCs, Bub1, encodes a cell-cycle regulator, central to the kinetochore complex, which regulates several histone proteins involved in cell proliferation. Downstream signaling analysis of lipedema ADSCs demonstrated enhanced activation of histone H2A, a key cell proliferation driver and Bub1 target. Critically, hyperproliferation exhibited by lipedema ADSCs was inhibited by the small molecule Bub1 inhibitor 2OH-BNPP1 and by CRISPR/Cas9-mediated Bub1 gene depletion.

Conclusion

We found significant differences in gene expression, and lipid and metabolite profiles, in tissue, ADSCs, and adipocytes from lipedema patients compared to non-affected controls. Functional assays demonstrated that dysregulated Bub1 signaling drives increased proliferation of lipedema ADSCs, suggesting a potential mechanism for enhanced adipogenesis in lipedema. Importantly, our characterization of signaling networks driving lipedema identifies potential molecular targets, including Bub1, for novel lipedema therapeutics.

Insulin Resistance and Cancer: In Search for a Causal Link

Insulin resistance (IR) is a condition which refers to individuals whose cells and tissues become insensitive to the peptide hormone, insulin. Over the recent years, a wealth of data has made it clear that a synergistic relationship exists between IR, type 2 diabetes mellitus, and cancer. Although the underlying mechanism(s) for this association remain unclear, it is well established that hyperinsulinemia, a hallmark of IR, may play a role in tumorigenesis. On the other hand, IR is strongly associated with visceral adiposity dysfunction and systemic inflammation, two conditions which favor the establishment of a pro-tumorigenic environment. Similarly, epigenetic modifications, such as DNA methylation, histone modifications, and non-coding RNA, in IR states, have been often associated with tumorigenesis in numerous types of human cancer. In addition to these observations, it is also broadly accepted that gut microbiota may play an intriguing role in the development of IR-related diseases, including type 2 diabetes and cancer, whereas potential chemopreventive properties have been attributed to some of the most commonly used antidiabetic medications. Herein we provide a concise overview of the most recent literature in this field and discuss how different but interrelated molecular pathways may impact on tumor development.

Novel strategies for glycaemic control and preventing diabetic complications applying the clustering-based classification of adult-onset diabetes mellitus: A perspective

Diabetes mellitus results from an interplay between insulin resistance and β-cell dysfunction. Since their relative contributions to its pathogenesis are difficult to quantify, therapeutic strategies for glycaemic control are determined primarily based on two limited metrics: plasma glucose and haemoglobin A1c. Recent attempts have been made to subclassify diabetes mellitus to better predict its associated pathology and plan appropriate therapeutic strategies. These classifications are based on data-driven cluster analysis using autoimmunity, age, obesity (metabolically unhealthy and healthy phenotypes), insulin secretory capacity and resistance, and ethnicity. This review addresses potential therapeutic strategies for the cluster-based classifications of adult-onset diabetes mellitus to achieve better glycaemic control and prevent or at least delay the concomitant complications.

Reversal of hypertriglyceridemia in diabetic BTBR ob/ob mice does not prevent nephropathy

The etiology of diabetic nephropathy in type 2 diabetes is multifactorial. Sustained hyperglycemia is a major contributor, but additional contributions come from the hypertension, obesity, and hyperlipidemia that are also commonly present in patients with type 2 diabetes and nephropathy. The leptin deficient BTBR ob/ob mouse is a model of type 2 diabetic nephropathy in which hyperglycemia, obesity, and hyperlipidemia, but not hypertension, are present. We have shown that reversal of the constellation of these metabolic abnormalities with leptin replacement can reverse the morphologic and functional manifestations of diabetic nephropathy. Here we tested the hypothesis that reversal specifically of the hypertriglyceridemia, using an antisense oligonucleotide directed against ApoC-III, an apolipoprotein that regulates the interactions of VLDL (very low density lipoproteins) with the LDL receptor, is sufficient to ameliorate the nephropathy of Type 2 diabetes. Antisense treatment resulted in reduction of circulating ApoC-III protein levels and resulted in substantial lowering of triglycerides to near-normal levels in diabetic mice versus controls. Antisense treatment did not ameliorate proteinuria or pathologic manifestations of diabetic nephropathy, including podocyte loss. These studies indicate that pathologic manifestations of diabetic nephropathy are unlikely to be reduced by lipid-lowering therapeutics alone, but does not preclude a role for such interventions to be used in conjunction with other therapeutics commonly employed in the treatment of diabetes and its complications.

In Vivo Magnetic Resonance Spectroscopy of Hyperpolarized [1-13 C]Pyruvate and Proton Density Fat Fraction in a Guinea Pig Model of Non-Alcoholic Fatty Liver Disease Development After Life-Long Western Diet Consumption

BACKGROUND

Alterations in glycolysis are central to the increasing incidence of non-alcoholic fatty liver disease (NAFLD), highlighting a need for in vivo, non-invasive technologies to understand the development of hepatic metabolic aberrations.

PURPOSE

To use hyperpolarized magnetic resonance spectroscopy (MRS) and proton density fat fraction (PDFF) magnetic resonance imaging (MRI) techniques to investigate the effects of a chronic, life-long exposure to the Western diet (WD) in an animal model resulting in NAFLD; to investigate the hypothesis that exposure to the WD will result in NAFLD in association with altered pyruvate metabolism.

STUDY TYPE

Prospective.

ANIMAL MODEL

Twenty-eight male guinea pigs weaned onto a control diet (N = 14) or WD (N = 14).

FIELD STRENGTH/SEQUENCE

3 T; T1-weighted gradient echo, T2-weighted spin-echo, three-dimensional gradient multi-echo fat-water separation (IDEAL-IQ), and broadband point-resolved spectroscopy (PRESS) chemical-shift sequences.

ASSESSMENT

Median PDFF was calculated in the liver and hind limbs. [1-¹³ C]pyruvate dynamic MRS in the liver was quantified by the time-to-peak (TTP) for each metabolite. Animals were euthanized and tissue was analyzed for lipid and cholesterol concentration and enzyme level and activity.

STATISTICAL TESTS

Unpaired Student's t-tests were used to determine differences in measurements between the two diet groups. The Pearson correlation coefficient was calculated to determine correlations between measurements.

RESULTS

Life-long WD consumption resulted in significantly higher liver PDFF and elevated triglyceride content in the liver. The WD group exhibited a decreased TTP for lactate production, and ex vivo analysis highlighted increased liver lactate dehydrogenase (LDH) activity.

DATA CONCLUSION

PDFF MRI results suggest differential fat deposition patterns occurring in animals fed a life-long WD characteristic of lean, or lacking excessive subcutaneous fat, NAFLD. The decreased liver lactate TTP and increased ex vivo LDH activity suggest lipid accumulation occurs in association with a shift from oxidative metabolism to anaerobic glycolytic metabolism in WD-exposed livers.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 1.

Adipokine signatures of subcutaneous and visceral abdominal fat in normal-weight and obese women with different metabolic profiles

INTRODUCTION

Metabolic syndrome arises from abnormal adipose function accompanied by insulin resistance. As early factors reflecting/impacting lipid storage dysfunction of adipose tissues, we sought to determine adipokine levels in subcutaneous and visceral adipose tissues (SAT and VAT).

MATERIAL AND METHODS

Gene and protein expression levels of leptin, adiponectin, and resistin were analysed in SAT and VAT of normal-weight and overweight/obese women, subclassified according to insulin resistance index, triglyceride, total, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol levels into metabolically healthy and "at risk" groups.

RESULTS

Compared with normal-weight women, obese women had higher serum leptin levels (p < 0.05), as well as increased leptin gene and protein expression in VAT. Conversely, expression levels of leptin were lower in SAT of obese women, and minor in the SAT of "at risk" groups of women, compared with weight-matched healthy groups. In addition, lower adiponectin levels were detected in SAT of metabolically healthy obese women (p < 0.01), and lower in SAT and VAT (p < 0.05) of "at risk" obese women compared to healthy, obese women. Significant differences in resistin levels were only observed in obese women; resistin gene expression was higher in VAT and SAT of obese, compared to normal-weight women. However, higher gene expression was not consistent with protein expression of resistin.

CONCLUSIONS

Low adiponectin in both examined adipose tissues and inappropriate leptin expression levels in SAT appear to be important characteristics of obesity-related metabolic syndrome. Intriguingly, this adipokine dysregulation is primary seen in SAT, suggesting that endocrine dysfunction in this abdominal depot may be an early risk sign of metabolic syndrome.

The Ubiquitin Ligase SIAH2 Negatively Regulates Glucocorticoid Receptor Activity and Abundance

Glucocorticoids are clinically essential drugs used routinely to control inflammation. However, a host of metabolic side effects manifests upon usage beyond a few days. In the present study, we tested the hypothesis that seven-in-absentia mammalian homolog-2 (SIAH2), a ubiquitin ligase that regulates adipogenesis, is important for controlling adipocyte size, inflammation, and the ability of adipose tissue to expand in response to a glucocorticoid challenge. Using mice with global deletion of SIAH2 exposed or not to corticosterone, we found that adipocytes are larger in response to glucocorticoids in the absence of SIAH2. In addition, SIAH2 regulates glucocorticoid receptor (GR) transcriptional activity and total GR protein abundance. Moreover, these studies reveal that there is an increased expression of genes involved in fibrosis and inflammatory signaling pathways found in white adipose tissue in response to glucocorticoids in the absence of SIAH2. In summary, this is the first study to identify a role for SIAH2 to regulate transcriptional activity and abundance of the GR, which leads to alterations in adipose tissue size and gene expression during in vivo exposure to glucocorticoids.

Mechanism of Transplanted Islet Engraftment in Visceral White Adipose Tissue

BACKGROUND

White adipose tissue (WAT) is a candidate transplantation site for islets. However, the mechanism of islet engraftment in WAT has not been fully investigated. In this study, we attempted to clarify the therapeutic effect and mechanism of islet transplantation into visceral WAT.

METHODS

Two hundred mouse islets were transplanted into epididymal WAT of syngeneic diabetic mice by wrapping islets with the tissue (fat-covered group). Mice that received intraperitoneal and renal subcapsular islet transplantations were used as negative and positive control groups, respectively.

RESULTS

The transplant efficacy, including improvements in blood glucose and plasma insulin levels and in glucose tolerance tests, of the fat-covered group was superior to the negative control group and almost equal to the positive control group. Vessel density of engrafted islets in the fat-covered group was higher than that in the positive control group. It was speculated that the mechanism of islet engraftment in WAT might consist of trapping islets in WAT, adhesion of islets via a combination of adhesion factors (fibronectin and integrin β1), and promotion of angiogenesis in islets by expression of angiogenic factors induced by adiponectin.

CONCLUSIONS

Visceral WAT is an important candidate for islet transplantation. Adhesion factors and adiponectin might contribute to islet engraftment into WAT. Further studies to elucidate the detailed mechanism are necessary.

The Prevalence and Predictors of Non-alcoholic Fatty Liver Disease in Morbidly Obese Women - A Cross-sectional Study from Southern India

BACKGROUND

The prevalence of obesity is increasing rapidly in India and so are its associated comorbidities. Non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of metabolic syndrome, is commonly associated with obesity. However, limited data are available on its prevalence and clinical indicators among morbidly obese Indian women. The aim of our study was to find the prevalence of NAFLD in morbidly obese Indian women and study the clinically measurable obesity indicators that would best predict NAFLD.

METHODS

This was a cross-sectional study, conducted in the Department of Endocrinology, Diabetes and Metabolism, Christian Medical College, Vellore. Women were enrolled who were diagnosed to have NAFLD on sonography. Anthropometric variables, such as body mass index, waist circumference, hip circumference, waist-hip ratio and waist-height ratio were measured and compared between the two groups. SPSS Statistics 21.0 software was used for analysing the data.

RESULTS

One hundred and six consecutive, morbidly obese women were recruited in this study. Nearly three-quarters (73.6%) of the 106 morbidly obese participants were found to have NAFLD. We found waist circumference, body mass index and waist-height ratio to be most useful in distinguishing between patients with and without NAFLD, and found waist-height ratio was the best screening tool for diagnosing NAFLD.

CONCLUSION

NAFLD is present in a large proportion of morbidly obese women. Waist-height ratio could be used a surrogate screening tool to detect NAFLD in resource-constrained settings.

Adipocyte Ceramides-The Nexus of Inflammation and Metabolic Disease

Adipose depots are heterogeneous tissues that store and sense fuel levels. Through the secretion of lipids, cytokines, and protein hormones (adipokines), they communicate with other organ systems, informing them of the organism's nutritional status. The adipose tissues include diverse types of adipocytes (white, beige, and brown) distinguished by the number/size of lipid droplets, mitochondrial density, and thermogenic capacity. Moreover, they include a spectrum of immune cells that modulate metabolic activity and tissue remodeling. The unique characteristics and interplay of these cells control the production of ceramides, a class of nutrient signals derived from fat and protein metabolism that modulate adipocyte function to regulate glucose and lipid metabolism. The excessive accumulation of ceramides contributes to the adipose tissue inflammation and dysfunction that underlies cardiometabolic disease. Herein we review findings on this important class of lipid species and discuss their role at the convergence point that links overnutrition/inflammation to key features of the metabolic syndrome.

Nonalcoholic fatty liver disease and type 2 diabetes: pathophysiological mechanisms shared between the two faces of the same coin

The pathophysiological mechanisms underlying the close relationship between nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are multiple, complex and only partially known. The purpose of this paper was to review the current knowledge of these mechanisms in a unified manner. Subjects with NAFLD and T2DM have established insulin resistance (IR), which exacerbates the two comorbidities. IR worsens NAFLD by increasing the accumulation of free fatty acids (FFAs) in the liver. This occurs due to an increase in the influx of FFAs from peripheral adipose tissue by the activation of hormone-sensitive lipase. In addition, there is de novo increased lipogenesis, a transcription factor, the sterols regulatory element-binding transcription factor 1c (SREBP-1c), which activates the expression of several genes strongly promotes lipogenesis by the liver and facilitate storage of triglycerides. Lipids accumulation in the liver induces a chronic stress in the endoplasmic reticulum of the hepatocytes. Genome-wide association studies have identified genetic variants associated with NAFLD severity, but unrelated to IR. In particular, the alteration of patatin-like phospholipase domain-containing protein 3 contributes to the susceptibility to NAFLD. Furthermore, the lipotoxicity of ceramides and diacylglycerol, well known in T2DM, triggers a chronic inflammatory process favoring the progression from hepatic steatosis to steatohepatitis. Reactive oxygen species produced by mitochondrial dysfunction trigger both liver inflammation and beta-cells damage, promoting the progression of both NAFLD and T2DM. The close association between NAFLD and T2DM is bidirectional, as T2DM may trigger both NAFLD onset and its progression, but NAFLD itself may contribute to the development of IR and T2DM. Future studies on the mechanisms will have to deepen the knowledge of the interaction between the two pathologies and should allow the identification of new therapeutic targets for the treatment of NAFLD, currently substantially absent.

Obesity as a contributor to immunopathology in pregnant and non-pregnant adults with COVID-19

The ongoing coronavirus disease 2019 (COVID‐19) pandemic has led to a global public health emergency with the need to identify vulnerable populations who may benefit from increased screening and healthcare resources. Initial data suggest that overall, pregnancy is not a significant risk factor for severe coronavirus disease 2019 (COVID‐19). However, case series have suggested that maternal obesity is one of the most important comorbidities associated with more severe disease. In obese individuals, suppressors of cytokine signaling are upregulated and type I and III interferon responses are delayed and blunted leading to ineffective viral clearance. Obesity is also associated with changes in systemic immunity involving a wide range of immune cells and mechanisms that lead to low‐grade chronic inflammation, which can compromise antiviral immunity. Macrophage activation in adipose tissue can produce low levels of pro‐inflammatory cytokines (TNF‐α, IL‐1β, IL‐6). Further, adipocyte secretion of leptin is pro‐inflammatory and high circulating levels of leptin have been associated with mortality in patients with acute respiratory distress syndrome. The synergistic effects of obesity‐associated delays in immune control of COVID‐19 with mechanical stress of increased adipose tissue may contribute to a greater risk of pulmonary compromise in obese pregnant women. In this review, we bring together data regarding obesity as a key co‐morbidity for COVID‐19 in pregnancy with known changes in the antiviral immune response associated with obesity. We also describe how the global burden of obesity among reproductive age women has serious public health implications for COVID‐19.

Ceramides in Adipose Tissue

Adipose tissue is a key nutrient-sensing depot that regulates excess energy storage and consumption. Adipocytes, the key components of the adipose tissue, have unique ability to store excess energy in the form of triglycerides, sense systemic energy demands, and secrete factors (lipids, peptides, cytokines, and adipokines) to regulate other metabolic tissues. The presence of various types of adipocytes (white, brown, and beige) characterized by the number/size of lipid droplets, mitochondrial density, and thermogenic capacity, further highlights how intricate is the communication of these cell-types with other metabolic tissues to sense nutrients. In obesity the inherent capacity of adipose tissue to store and sense nutrients is compromised, causing spillover of the intermediate lipid metabolites into circulation and resulting in their ectopic deposition in tissues not suitable for lipid storage, a phenomenon known as lipotoxicity. This results in a spectrum of cellular dysfunction, that underlies various metabolic diseases. Of the numerous lipid classes implicated in eliciting lipotoxicity, sphingolipid: ceramides are among the most deleterious as they modulate signaling pathways involved in regulating glucose metabolism, triglyceride synthesis, apoptosis, and fibrosis. Notably, recent experimental studies have strongly implicated ceramides in the development of numerous metabolic diseases such as insulin resistance, diabetes, cardiomyopathy, hepatic-steatosis, and atherosclerosis. Herein we discuss and summarizes recent findings that implicate ceramides as a key contributor to adipocyte dysfunction underlying metabolic diseases and how depletion of ceramides can be exploited to improve metabolic health.

Ceramide and Sphingosine 1-Phosphate in Liver Diseases

The liver is an important organ in the regulation of glucose and lipid metabolism. It is responsible for systemic energy homeostasis. When energy need exceeds the storage capacity in the liver, fatty acids are shunted into nonoxidative sphingolipid biosynthesis, which increases the level of cellular ceramides. Accumulation of ceramides alters substrate utilization from glucose to lipids, activates triglyceride storage, and results in the development of both insulin resistance and hepatosteatosis, increasing the likelihood of major metabolic diseases. Another sphingolipid metabolite, sphingosine 1-phosphate (S1P) is a bioactive signaling molecule that acts via S1P-specific G protein coupled receptors. It regulates many cellular and physiological events. Since an increase in plasma S1P is associated with obesity, it seems reasonable that recent studies have provided evidence that S1P is linked to lipid pathophysiology, including hepatosteatosis and fibrosis. Herein, we review recent findings on ceramides and S1P in obesity-mediated liver diseases and the therapeutic potential of these sphingolipid metabolites.

Abnormalities of Skeletal Muscle, Adipocyte Tissue, and Lipid Metabolism in Heart Failure: Practical Therapeutic Targets

Chronic diseases, including heart failure (HF), are often accompanied with skeletal muscle abnormalities in both quality and quantity, which are the major cause of impairment of the activities of daily living and quality of life. We have shown that skeletal muscle abnormalities are a hallmark of HF, in which metabolic pathways involving phosphocreatine and fatty acids are largely affected. Not only in HF, but the dysfunction of fatty acid metabolism may also occur in many chronic diseases, such as arteriosclerosis, as well as through insufficient physical exercise. Decreased fatty acid catabolism affects adenosine triphosphate (ATP) production in mitochondria, via decreased activity of the tricarboxylic acid cycle; and may cause abnormal accumulation of adipose tissue accompanied with hyperoxidation and ectopic lipid deposition. Such impairments of lipid metabolism are in turn detrimental to skeletal muscle, which is hence a chicken-and-egg problem between skeletal muscle and HF. In this review, we first discuss skeletal muscle abnormalities in HF, including sarcopenia; particularly their association with lipid metabolism and adipose tissue. On the other hand, the precise mechanisms involved in metabolic reprogramming and dysfunction are beginning to be understood, and an imbalance of daily nutritional intake of individuals has been found to be a causative factor for the development and worsening of HF. Physical exercise has long been known to be beneficial for the prevention and even treatment of HF. Again, the molecular mechanisms by which exercise promotes skeletal muscle as well as cardiac muscle functions are being clarified by recent studies. We propose that it is now the time to develop more “natural” methods to prevent and treat HF, rather than merely relying on drugs and medical interventions. Further analysis of the basic design of and molecular mechanisms involved in the human body, particularly the inextricable association between physical exercise and the integrity and functional plasticity of skeletal and cardiac muscles is required.

Bifidobacterium animalis subsp. lactis 420 for Metabolic Health: Review of the Research

The growing worldwide epidemic of obesity and associated metabolic health comorbidities has resulted in an urgent need for safe and efficient nutritional solutions. The research linking obesity with gut microbiota dysbiosis has led to a hypothesis that certain bacterial strains could serve as probiotics helping in weight management and metabolic health. In the search for such strains, the effect of Bifidobacterium animalis subsp. lactis 420 (B420) on gut microbiota and metabolic health, and the mechanisms of actions, has been investigated in a variety of in vitro, pre-clinical, and clinical studies. In this review, we aim to highlight the research on B420 related to obesity, metabolic health, and the microbiota. Current research supports the hypothesis that gut dysbiosis leads to an imbalance in the inflammatory processes and loss of epithelial integrity. Bacterial components, like endotoxins, that leak out of the gut can invoke low-grade, chronic, and systemic inflammation. This imbalanced state is often referred to as metabolic endotoxemia. Scientific evidence indicates that B420 can slow down many of these detrimental processes via multiple signaling pathways, as supported by mechanistic in vitro and in vivo studies. We discuss the connection of these mechanisms to clinical evidence on the effect of B420 in controlling weight gain in overweight and obese subjects. The research further indicates that B420 may improve the epithelial integrity by rebalancing a dysbiotic state induced by an obesogenic diet, for example by increasing the prevalence of lean phenotype microbes such as Akkermansia muciniphila. We further discuss, in the context of delivering the health benefits of B420: the safety and technological aspects of the strain including genomic characterization, antibiotic resistance profiling, stability in the product, and survival of the live probiotic in the intestine. In summary, we conclude that the clinical and preclinical studies on metabolic health suggest that B420 may be a potential candidate in combating obesity; however, further clinical studies are needed.

Hepatic Expression of the Serine Palmitoyltransferase Subunit Sptlc2 Reduces Lipid Droplets in the Liver by Activating VLDL Secretion

Objective

Ceramide is a signaling molecule that contributes to insulin resistance and hepatosteatosis. In the present study, we activated de novo ceramide synthesis by inducing the hepatic expression of Sptlc2 to investigate the role of ceramide in glucose and lipid metabolism.

Methods

We first constructed an adenovirus containing Sptlc2 (AdSptlc2), which encodes a major catalytic subunit of serine palmitoyltransferase (SPT). We then infected hepatocytes and mice fed a regular diet with AdSptlc2 to activate de novo ceramide biosynthesis. The liver-specific effects of ceramide biosynthesis on glucose and lipid metabolism were investigated by measuring changes in insulin signaling, lipid droplet formation, and very low-density lipoprotein (VLDL) secretion.

Results

In HepG2 hepatocytes, adenoviral Sptlc2 expression inhibited insulin signaling and increased ceramide levels via activation of c-Jun N-terminal kinase and serine phosphorylation of insulin receptor substrate 1. In contrast, in mice, AdSptlc2 infection decreased plasma glucose levels by downregulating gluconeogenic genes and increased plasma triglyceride levels by increasing VLDL secretion. In mice infected with AdSptlc2, glucose intolerance and insulin sensitivity improved, while pyruvate utilization via gluconeogenesis decreased.

Conclusion

Hepatic ceramide was found to modulate hepatosteatosis and the insulin response via increased VLDL secretion and inhibition of gluconeogenesis in vivo. Although inhibition of the insulin response was observed in vitro, the compensatory mechanism of relieving ceramide-induced stress and reducing ceramide levels resulted in improvements of glucose and lipid metabolic profiles in vivo. This discrepancy between in vitro and in vivo regulation mechanisms suggests that ceramide plays a role in non-alcoholic fatty liver disease and insulin resistance.

Metabolically Healthy Obesity-Heterogeneity in Definitions and Unconventional Factors

The concept of heterogeneity among obese individuals in their risk for developing metabolic dysfunction and associated complications has been recognized for decades. At the origin of the heterogeneity idea is the acknowledgement that individuals with central obesity are more prone to developing type 2 diabetes and cardiovascular disease than those with peripheral obesity. There have been attempts to categorize subjects according to their metabolic health and degree of obesity giving rise to different obese and non-obese phenotypes that include metabolically unhealthy normal-weight (MUHNW), metabolically healthy obese (MHO), and metabolically unhealthy obese (MUO). Individuals belonging to the MHO phenotype are obese according to their body mass index although exhibiting fewer or none metabolic anomalies such as type 2 diabetes, dyslipidemia, hypertension, and/or unfavorable inflammatory and fribinolytic profiles. However, some authors claim that MHO is only transient in nature. Additionally, the phenotype categorization is controversial as it lacks standardized definitions possibly blurring the distinction between obesity phenotypes and confounding the associations with health outcomes. To add to the discussion, the factors underlying the origin or protection from metabolic deterioration and cardiometabolic risk for these subclasses are being intensely investigated and several hypotheses have been put forward. In the present review, we compare the different definitions of obesity phenotypes and present several possible factors underlying them (adipose tissue distribution and cellularity, contaminant accumulation on the adipose tissue, dysbiosis and metabolic endotoxemia imposing on to the endocannabinoid tone and inflammasome, and nutrient intake and dietary patterns) having inflammatory activation at the center.

Amelioration of hippocampal dysfunction by adipose tissue-targeted stem cell transplantation in a mouse model of type 2 diabetes

There is growing evidence that type 2 diabetes or insulin resistance is linked to cognitive impairment. We recently confirmed altered lipid composition, down-regulation of insulin receptor expression and impaired basal synaptic transmission in the hippocampus of our transgenic murine model of adipocyte insulin resistance (AtENPP1-Tg). Here we evaluated whether the correction of adipose tissue dysfunction [via the subcutaneous transplantation of mesenchymal stem cells (MSC)] can improve the hippocampal synaptic transmission in AtENPP1-Tg mice versus their wildtype littermates. Animals were simply randomized to receive MSC, then weighed weekly for 12 weeks. At euthanasia, we assessed leptin in the collected serum and hippocampal synaptic high-frequency stimulation long-term potentiation (HFS-LTP) using brain slices. MSC transplantation normalized AtENPP1-Tg body and epididymal fat weights and was associated with increased leptin levels, a sign of adipocyte maturation. More importantly, transplantation restored the deficiency observed in AtENPP1-Tg HFS-LTP, the cellular readout of memory. Our results further corroborate the role of adipocyte maturation arrest in adipose tissue and highlight a role for the adipose tissue in modulating hippocampal cellular mechanisms. Further studies are warranted to explore the mechanisms for the MSC-induced improvement of hippocampal HFS-LTP.

Oxygenation of adipose tissue: A human perspective

Obesity is a complex disorder of excessive adiposity, and is associated with adverse health effects such as cardiometabolic complications, which are to a large extent attributable to dysfunctional white adipose tissue. Adipose tissue dysfunction is characterized by adipocyte hypertrophy, impaired adipokine secretion, a chronic low‐grade inflammatory status, hormonal resistance and altered metabolic responses, together contributing to insulin resistance and related chronic diseases. Adipose tissue hypoxia, defined as a relative oxygen deficit, in obesity has been proposed as a potential contributor to adipose tissue dysfunction, but studies in humans have yielded conflicting results. Here, we will review the role of adipose tissue oxygenation in the pathophysiology of obesity‐related complications, with a specific focus on human studies. We will provide an overview of the determinants of adipose tissue oxygenation, as well as the role of adipose tissue oxygenation in glucose homeostasis, lipid metabolism and inflammation. Finally, we will discuss the putative effects of physiological and experimental hypoxia on adipose tissue biology and whole‐body metabolism in humans. We conclude that several lines of evidence suggest that alteration of adipose tissue oxygenation may impact metabolic homeostasis, thereby providing a novel strategy to combat chronic metabolic diseases in obese humans.

Advantages of Phosphodiesterase Type 5 Inhibitors in the Management of Glucose Metabolism Disorders: A Clinical and Translational Issue

Among metabolic diseases, carbohydrate metabolism disorders are the most widespread. The most common glucose pathological conditions are acquired and may increase the risk of type 2 diabetes, obesity, heart diseases, stroke, and kidney insufficiency. Phosphodiesterase type 5 inhibitors (PDE5i) have long been used as an effective therapeutic option for the treatment of erectile dysfunction (ED). Different studies have demonstrated that PDE5i, by sensitizing insulin target tissues to insulin, play an important role in controlling the action of insulin and glucose metabolism, highlighting the protective action of these drugs against metabolic diseases. In this review, we report the latest knowledge about the role of PDE5i in the metabolic diseases of insulin resistance and type 2 diabetes, highlighting clinical aspects and potential treatment approaches. Although various encouraging data are available, further in vivo and in vitro studies are required to elucidate the mechanism of action and their clinical application in humans.

Pancreatic Fat is not significantly correlated with β-cell Dysfunction in Patients with new-onset Type 2 Diabetes Mellitus using quantitative Computed Tomography

Objective: Type 2 diabetes mellitus (T2DM) is a chronic condition resulting from insulin resistance and insufficient β-cell secretion, leading to improper glycaemic regulation. Previous studies have found that excessive fat deposits in organs such as the liver and muscle can cause insulin resistance through lipotoxicity that affects β-cell function. The relationships between fat deposits in pancreatic tissue, the function of β-cells, the method of visceral fat evaluation and T2DM have been sought by researchers. This study aims to elucidate the role of pancreatic fat deposits in the development of T2DM using quantitative computed tomography (QCT), especially their effects on islet β-cell function. Methods: We examined 106 subjects at the onset of T2DM who had undergone abdominal QCT. Estimated pancreatic fat and liver fat were quantified using QCT and calculated. We analysed the correlations with Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) scores and other oral glucose tolerance test-derived parameters that reflect islet function. Furthermore, correlations of estimated pancreatic fat and liver fat with the area under the curve for insulin (AUC_INS) and HOMA-IR were assessed with partial correlation analysis and demonstrated by scatter plots. Results: Associations were found between estimated liver fat and HOMA-IR, AUC_INS, the modified β-cell function index (MBCI) and Homeostatic Model Assessment β (HOMA-β). However, no significant differences existed between estimated pancreas fat and those parameters. Similarly, after adjustment for sex, age and body mass index, only estimated liver fat was correlated with HOMA-IR and AUC_INS. Conclusions: This study suggests no significant correlation between pancreatic fat deposition and β-cell dysfunction in the early stages of T2DM using QCT as a screening tool. The deposits of fat in the pancreas and the resulting lipotoxicity may play an important role in the late stage of islet cell function dysfunction as the course of T2DM progresses.

Asprosin: A Novel Player in Metabolic Diseases

Asprosin, a novel glucogenic adipokine, is encoded by two exons (exon 65 and exon 66) of the gene Fibrillin 1 (FBN1) and mainly synthesized and released by white adipose tissue during fasting. Asprosin plays a complex role in the central nervous system (CNS), peripheral tissues, and organs. It is involved in appetite, glucose metabolism, insulin resistance (IR), cell apoptosis, etc. In this review, we will summarize the newly discovered roles of asprosin in metabolic diseases including diabetes, obesity, polycystic ovarian syndrome (PCOS), and cardiovascular disease (CVD), which may contribute to future clinical diagnosis and treatment.

The Association between Adult Weight Gain and Insulin Resistance at Middle Age: Mediation by Visceral Fat and Liver Fat

We aimed to investigate the role of the amount of visceral fat and liver fat in the association between adult weight change and insulin resistance at middle age. In the Netherlands Epidemiology of Obesity study, adult weight change was calculated with recalled body weight at age 20 years and measured body weight at middle age. Measures of insulin resistance were calculated using both fasting and postprandial glucose and insulin concentrations. Visceral fat was assessed by magnetic resonance (MR) imaging and liver fat by proton-MR spectroscopy (N = 1758). We examined the association between adult weight change and insulin resistance with linear regression, adjusted for confounding factors. To investigate mediation, we additionally adjusted for total body fat, visceral fat, and liver fat. In participants who gained ≥50% of body weight during adulthood, homeostatic model assessment for insulin resistance (HOMA-IR) was 3.22 (95% CI 2.76; 3.77) times higher than in weight maintainers. In a joint model, total body fat mediated this association for 8.1% (95% CI −9.2; 25.4), visceral fat for 32.0% (18.6; 45.4%) and liver fat for 22.5% (15.0; 30.1). The association between adult weight gain and insulin resistance at middle age is largely mediated by both visceral fat and liver fat.

Risk factors for ischemic stroke in patients with non-valvular atrial fibrillation and therapeutic international normalized ratio range

INTRODUCTION

Atrial fibrillation (AF) is the most common cause of ischemic stroke (IS). Atrial fibrillation patients are recommended to use oral anticoagulants (OACs) as part of prevention against IS. However, despite having a therapeutic intensity of OAC therapy, IS can still occur in such patients. The aim of our study was to examine the configuration of IS risk factors in patients with non-valvular atrial fibrillation (NVAF) and within the therapeutic INR range (TINR).

MATERIAL AND METHODS

Our retrospective study involved 1835 patients with a recent IS. The experimental group consisted of 154 patients with acute IS, NVAF and TINR. The control group consisted of 1681 patients with acute IS but without AF.

RESULTS

Patients with IS, NVAF and TINR were significantly older and more often female than patients with IS without NVAF (p < 0.001 and p < 0.001, respectively). In these patients, diabetes mellitus, dyslipidemia, hypertension, coronary heart disease, smoking and previous IS were significantly more frequent than in the patients with IS without NVAF (p = 0.036, p = 0.002, p < 0.001, p < 0.001, p < 0.001, p = 0.003). Based on a univariable and multivariable logistic regression model, we found that in the group of patients who suffered a stroke despite TINR compared to patients with IS without AF there were more smokers (OR = 20.337; OR = 147.589) and patients with previous stroke (OR = 6.556; OR = 11.094), hypertension (OR = 3.75; OR = 2.75) and dyslipidemia (OR = 2.318; OR = 2.294).

CONCLUSIONS

The group of patients with NVAF and TINR is significantly more burdened by other independent common risk factors for stroke.