Ectopic fat: the true culprit linking obesity and cardiovascular disease?

Changes in abdominal adipose tissues and ectopic fat depots during pregnancy are dissociated from gestational weight gain

OBJECTIVE

The study objective was to evaluate changes in abdominal adipose tissue and ectopic fat during pregnancy and their associations with gestational weight gain (GWG) in women with overweight/obesity.

METHODS

This study was a secondary analysis of a randomized controlled trial. Magnetic resonance scans were performed during gestational week (GW) 15, GW 32, and around birth to measure abdominal subcutaneous (SAT) and visceral (VAT) adipose tissues, liver fat, and muscle fat. Linear mixed models and multivariable linear regression analyses were utilized, adjusting for prepregnancy BMI, parity, and randomization.

RESULTS

Among 119 women, VAT and SAT decreased from GW 15 to GW 32 but rebounded at birth; final levels were lower than at GW 15. Liver fat and muscle fat did not change significantly. GWG was positively associated with changes in SAT but not with those in VAT, liver fat, or muscle fat.

CONCLUSIONS

This study demonstrates dynamic changes in abdominal fat depots during pregnancy in women with overweight/obesity. The observed reduction in VAT and SAT during pregnancy and the association of GWG with SAT suggest that weight gain during pregnancy may be less metabolically harmful than outside pregnancy. Future research should investigate the mechanisms and long-term effects on maternal and child health.

Mouse models for metabolic health research: molecular mechanism of exercise effects on health improvement through adipose tissue remodelling

Exercise provides health benefits to multiple metabolic tissues through complex biological pathways and interactions between organs. However, investigating these complex mechanisms in humans is still limited, making mouse models extremely useful for exploring exercise-induced changes in whole-body metabolism and health. In this review, we focus on gaining a broader understanding of the metabolic phenotypes and molecular mechanisms induced by exercise in mouse models. We first discuss the differences in adaptations induced by aerobic and resistance exercise, and compare voluntary wheel running and forced treadmill exercise, the two main methods of aerobic exercise research in mice, to show the similarities and differences between the same aerobic exercise but different methods, and their impact on experimental outcomes. The effects of exercise on metabolic phenotypes, including alleviation of obesity and metabolic disorders, and the mechanisms involved in adipose tissue remodelling and browning are explored, as well as the role of the gut microbiota in mediating the physiological responses and metabolic effects of exercise. Understanding these molecular mechanisms and methodological aspects of exercise experiments in mouse models can serve as a valuable template for the design of future basic research in exercise physiology and will provide a strong scientific evidence base for optimizing the design of exercise intervention programmes for metabolic health.

Antarctic Krill Euphausia superba Oil Supplementation Attenuates Hypercholesterolemia, Fatty Liver, and Oxidative Stress in Diet-Induced Obese Mice

BACKGROUND

Several Previous studies indicate that consuming krill oil may aid in reducing hypercholesterolemia and improving cholesterol metabolism. Therefore, our study was designed to investigate the effectiveness of Antarctic krill oil (Euphausia superba) (ESKO) in combating obesity and lowering fat/lipid/cholesterol levels.

METHODS

The study aimed to investigate the molecular docking model targeting 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) using ESKO-derived eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and astaxanthin. In this study, histological alterations in the liver of the obesity model (ICR male mouse), obesity-related or antioxidant markers in both liver and serum, the molecular mechanisms in HepG2 cells and liver tissue, and HMGCR activity were analyzed.

RESULTS

Our findings revealed that a high-fat diet (HFD) significantly led to increased oxidative stress, obesity-related indicators, and cardiovascular-associated risk indices. However, ESKO effectively mitigated HFD-induced oxidative stress, fat accumulation, and the suppression of low-density lipoprotein receptor (LDLR) or activation of related molecular pathways. This was achieved through improvements in metabolic parameters, including CD36/liver X receptor α (LXRα)/sterol regulatory element-binding protein 1c (SREBP1c), proprotein convertase subtilsin/kexin type 9 (PCSK-9), and HMGCR, ultimately ameliorating HFD-induced hypercholesterolemia and obesity.

CONCLUSIONS

These beneficial findings indicate that ESKO might have significant potential for preventing and treating obesity-related disorders.

Sex differences in Alzheimer's disease blood biomarkers in a Caribbean population of African ancestry: The Tobago Health Study

INTRODUCTION

Alzheimer's disease (AD) is increasing in the Caribbean, especially for persons of African ancestry (PAA) and women. However, studies have mostly utilized surveys without AD biomarkers.

METHODS

In the Tobago Health Study (n = 309; 109 women, mean age 70.3 ± 6.6), we assessed sex differences and risk factors for serum levels of phosphorylated tau-181 (p-tau181), amyloid-beta (Aβ)42/40 ratio, glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL). Blood samples were from 2010 to 2013 for men and from 2019 to 2023 for women.

RESULTS

Women were more obese, hypertensive, and sedentary but reported less smoking and alcohol use than men (age-adjusted p < 0.04). Compared to men, women had worse levels of AD biomarkers, with higher p-tau181 and lower Aβ42/40, independent of covariates (p < 0.001). In sex-stratified analyses, higher p-tau181 was associated with older age in women and with hypertension in men. GFAP and NfL did not differ by sex.

DISCUSSION

Women had worse AD biomarkers than men, unexplained by age, cardiometabolic diseases, or lifestyle. Studying risk factors for AD in PAA is warranted, especially for women earlier in life.

Cardiovascular risk in bipolar disorder - A case for the hypothalamus-pituitary-adrenal axis?

BACKGROUND

Unipolar major depressive disorder (MDD) and bipolar disorder (BD) are associated with elevated mortality risk secondary to natural causes. Cardiovascular disease (CVD) constitutes the most prevalent underlying condition. Patients with BD display higher CVD-associated excess mortality than MDD patients. Epicardial adipose tissue (EAT) volume, a known predictor of premature CV morbidity and adrenal gland (AG) volume, an indicator for chronic hypothalamus-pituitary-adrenal (HPA) axis activation, were compared in BD and MDD patients.

METHODS

Magnetic resonance imaging was performed to assess EAT and AG volume in age-, gender-, and body mass index (BMI)-matched MDD (N = 27) and BD (N = 27) patients. Ten-year CV mortality risk and diabetes risk were assessed by PROCAM, ESC-SCORE, and FINDRISK, respectively; metabolic syndrome (MetS) was determined following NCEP/ATP III criteria.

RESULTS

Cardiometabolic risk scores and frequency of MetS were comparable, and scores of cardiometabolic risk indices did not significantly differ in both groups. After adjustment for age, BMI, and physical activity, EAT and AG volumes were significantly higher in BD compared to MDD. Partial correlation analyses showed a significant positive association of EAT and AG volumes in BD but not in the MDD.

LIMITATIONS

The modest sample size warrants confirmation in a larger cohort and the cross-sectional design does not allow for temporal or causal inferences.

CONCLUSION

Our study indicates increased EAT accumulation in BD patients. This was associated with HPA axis dysregulation. Therapeutic lifestyle interventions that reduce EAT volume should be considered in clinical BD management.

Adipose Tissue Compartments, Inflammation, and Cardiovascular Risk in the Context of Depression

The neurobiological and behavioral underpinnings linking mental disorders, in particular, major depressive disorder (MDD), with cardiovascular disorders are a matter of debate. Recent research focuses on visceral (intra-abdominal and epicardial) adipose tissue and inflammation and their impact on the development of cardiometabolic disorders. Intra-abdominal adipose tissue is defined as an endocrine active fat compartment surrounding inner organs and is associated with type 2 diabetes mellitus, a risk factor for the later development of cardiovascular disorders. Epicardial (pericardial) adipose tissue is a fat compartment surrounding the heart with close proximity to the arteries supporting the heart. Visceral adipose tissue (VAT) is an important source of inflammatory mediators that, in concert with other risk factors, plays a leading role in cardiovascular diseases. In conjunction with the behavioral (physical inactivity, sedentary lifestyle), psychological (adherence problems), and hormonal (dysfunction of the hypothalamus-pituitary-adrenal axis with subsequent hypercortisolism) alterations frequently accompanying MDD, an enhanced risk for cardiovascular disorders results.

The Effect of High-intensity Interval Training vs Moderate-intensity Continuous Training on Liver Fat: A Systematic Review and Meta-Analysis

CONTEXT

Non-alcoholic fatty liver disease, characterized by excess fat accumulation in the liver, is considered the hepatic manifestation of metabolic syndrome. Recent findings have shown that high-intensity interval training (HIIT) can reduce liver fat but it is unclear whether this form of exercise is superior to traditional moderate-intensity continuous training (MICT).

OBJECTIVE

The aim of this systematic review was to determine the effect of HIIT vs MICT on liver fat in adults. A secondary aim was to investigate the interaction between total weekly exercise volume and exercise-related energy expenditure and change in liver fat.

METHODS

Relevant databases were searched up to December 2020 for randomized trials, comparing HIIT to control, MICT to control, or HIIT to MICT. Studies were excluded if they did not implement 2 or more weeks' intervention or assess liver fat using magnetic resonance-based techniques. Weighted mean differences and 95% CIs were calculated. Regression analyses were undertaken to determine the interaction between weekly exercise volume in minutes and kilocalories (kcal) with change in liver fat content.

RESULTS

Of the 28 268 studies screened, 19 were included involving 745 participants. HIIT and MICT both elicited moderate reductions in liver fat content when compared to control (HIIT: -2.85%, 95% CI, -4.86 to -0.84, P = .005, I2 = 0%, n = 114, low-certainty evidence; MICT: -3.14%, 95% CI, -4.45 to -1.82, P < .001, I2 = 5.2%, n = 533, moderate-certainty evidence). There was no difference between HIIT and MICT (-0.34%, 95% CI, -2.20 to 1.52, P = .721, I2 = 0%, n = 177, moderate-certainty evidence). Neither total exercise volume in minutes (β = .0002, SE = 0.0017, Z = 0.13, P = .89) nor exercise-related energy expenditure in kcal (β = .0003, SE = 0.0002, Z = 1.21, P = .23) were related to changes in liver fat content.

CONCLUSION

HIIT elicits comparable improvements in liver fat to MICT despite often requiring less energy and time commitment. Further studies should be undertaken to assess the relative importance of aerobic exercise prescription variables, such as intensity, on liver fat.

Neck Circumference and Risk of Incident Atrial Fibrillation in the Framingham Heart Study

Background

Increased neck circumference, a proxy for upper‐body subcutaneous fat, is associated with cardiovascular risk and metabolic risk factors, accounting for body mass index (BMI) and waist circumference. The association between neck circumference and incident atrial fibrillation (AF) is unclear. The aim of current study was to evaluate the association between neck circumference and incident AF.

Methods and Results

We selected participants from the Framingham Heart Study aged ≥55 years without diagnosed AF and with available neck circumference, BMI, and waist circumference measurements. We defined high neck circumference as ≥14 inches in women and ≥17 inches in men on the basis of the Contal and O’Quigley changepoint method. We used Fine‐Gray models to estimate subdistribution hazards ratios (sHRs) for the association between neck circumference and incident AF accounting for the competing risk of death. We adjusted models for clinical risk factors. We then additionally adjusted separately for BMI, waist circumference, and height/weight. The study sample included 4093 participants (mean age 64±7 years, 55% female). During 11.2±5.7 mean years of follow‐up, incident AF occurred in 571 participants. High neck circumference was associated with incident AF (sHR for high versus low: 1.58; 95% CI, 1.32–1.90, P<0.0001). The association remained significant after adjustment for BMI (sHR, 1.51; 95% CI, 1.21–1.89; P=0.0003), waist circumference (sHR, 1.47; 95% CI, 1.18–1.83; P<0.0001), and height/weight (sHR, 1.37; 95% CI, 1.09–1.72; P=0.007).

Conclusions

High neck circumference was associated with incident AF adjusting for traditional adiposity measures such as BMI and waist circumference.

PPAR-γ-induced changes in visceral fat and adiponectin levels are associated with improvement of steatohepatitis in patients with NASH

BACKGROUND AND AIMS

Peroxisome proliferator-activated receptor (PPAR)-γ agonists decrease hepatic/visceral fat (VF) and improve necroinflammation despite subcutaneous (SC) fat weight-gain. Understanding the impact of changes in VF, VF-to-SC fat distribution (VF/SC) and adiponectin (ADPN) levels in relation to histological improvement after weight-loss or pioglitazone is relevant as novel PPAR-γ agonists are being developed for treating non-alcoholic steatohepatitis (NASH).

METHODS

Fifty-five patients with NASH received a -500 kcal/d hypocaloric diet and were randomized (double-blind) to pioglitazone (45 mg/d) or placebo for 6-months. Before and after treatment patients underwent a liver biopsy and measurement of hepatic/peripheral glucose fluxes, hepatic/adipose tissue-IR and, in 35 patients, hepatic and VF/SC-fat was measured by magnetic resonance spectroscopy/imaging. Data were examined by multivariable statistical analyses combined with machine-learning techniques (partial least square discriminant analysis [PLS-DA]).

RESULTS

Both pioglitazone (despite weight-gain) and placebo (if weight-loss) reduced steatosis but only pioglitazone ameliorated necroinflammation. Using machine-learning PLS-DA showed that the treatment differences induced by a PPAR-γ agonist vs placebo on metabolic variables and liver histology could be best explained by the increase in ADPN and a decrease in VF/SC, and to a lesser degree, improvement in oral glucose tolerance test-glucose concentrations and ALT. Decrease in steatosis and disease activity score (ballooning plus lobular inflammation) kept a close relationship with an increase in ADPN (r = -.71 and r = -.44, P < .007, respectively) and reduction in VF/SC fat (r = .41 and r = .37, P < .03 respectively).

CONCLUSIONS

Reduction in VF and improved VF/SC-distribution, combined with an increase in ADPN, mediate the histological benefits of PPAR-γ action, highlighting the central role of fat metabolism and its distribution on steatohepatitis disease activity in patients with NASH.

A review on interplay between obesity, lipoprotein profile and nutrigenetics with selected candidate marker genes of type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus, a rapidly growing epidemic, and its frequently related complications demand global attention. The two factors commonly attributed to the epidemic are genetic factors and environmental factors. Studies indicate that the genetic makeup at an individual level and the environmental aspects influence the occurrence of the disease. However, there is insufficiency in understanding the mechanisms through which the gene mutations and environmental components individually lead to T2DM. Also, discrepancies have often been noted in the association of gene variants and type 2 diabetes when the gene factor is examined as a sole attribute to the disease.

STUDY

In this review initially, we have focused on the proposed ways through which CAPN10, FABP2, GLUT2, TCF7L2, and ENPP1 variants lead to T2DM along with the inconsistencies observed in the gene-disease association. The article also emphasizes on obesity, lipoprotein profile, and nutrition as environmental factors and how they lead to T2DM. Finally, the main objective is explored, the environment-gene-disease association i.e. the influence of each environmental factor on the aforementioned specific gene-T2DM relationship to understand if the disease-causing capability of the gene variants is exacerbated by environmental influences.

CONCLUSION

We found that environmental factors may influence the gene-disease relationship. Reciprocally, the genetic factors may alter the environment-disease relationship. To precisely conclude that the two factors act synergistically to lead to T2DM, more attention has to be paid to the combined influence of the genetic variants and environmental factors on T2DM occurrence instead of studying the influence of the factors separately.

Associations of fitness and physical activity with specific abdominal fat depots in children with overweight/obesity

OBJECTIVES

To examine the relationship between physical fitness and physical activity (PA) with specific abdominal fat depots and their potential implications for cardiometabolic risk and insulin resistance (IR) in children with overweight/obesity.

MATERIALS AND METHODS

A total of 116 children with overweight/obesity (10.7 ± 1.1 year, 54% girls) participated in the study. Abdominal visceral (VAT), subcutaneous (ASAT), and intermuscular abdominal adipose tissue (IMAAT) were assessed by magnetic resonance imaging. The cardiometabolic risk (MetS) score and the insulin resistance homeostasis model assessment (HOMA-IR) were calculated. Health-related physical fitness components (treadmill test, and 20 m shuttle run, handgrip, standing broad jump and 4 × 10 m tests) were evaluated, and PA was measured (accelerometry). Children were categorized as fit or unfit for each specific fitness test, and as active or inactive.

RESULTS

Higher VAT, ASAT, and IMAAT were associated with higher MetS score and HOMA-IR (all p < 0.02). A better performance in all fitness tests and total and vigorous PA were strongly associated with lower VAT (all p < 0.04), ASAT (all p < 0.005), and IMAAT (all p < 0.005). Fit or active children had lower VAT, ASAT, and IMAAT (all p < 0.03) than their unfit or inactive counterparts.

CONCLUSION

These results reinforce the importance of having adequate fitness and PA levels to reduce abdominal fat accumulation in children. Given that VAT, ASAT, and IMAAT are associated with higher risk of developing cardiovascular diseases and type 2 diabetes, the improvement of physical fitness by the promotion of PA should be goals of lifestyle interventions for improving health in children with overweight/obesity.

Prolonged Chronic Consumption of a High Fat with Sucrose Diet Alters the Morphology of the Small Intestine

(1) The high-fat diet (HFD) of western countries has dramatic effect on the health of several organs, including the digestive tract, leading to the accumulation of fats that can also trigger a chronic inflammatory process, such as that which occurs in non-alcohol steatohepatitis. The effects of a HFD on the small intestine, the organ involved in the absorption of this class of nutrients, are still poorly investigated. (2) To address this aspect, we administered a combined HFD with sucrose (HFD w/Suc, fat: 58% Kcal) regimen (18 months) to mice and investigated the morphological and molecular changes that occurred in the wall of proximal tract of the small intestine compared to the intestine of mice fed with a standard diet (SD) (fat: 18% Kcal). (3) We found an accumulation of lipid droplets in the mucosa of HFD w/Suc-fed mice that led to a disarrangement of mucosa architecture. Furthermore, we assessed the expression of several key players involved in lipid metabolism and inflammation, such as perilipin, leptin, leptin receptor, PI3K, p-mTOR, p-Akt, and TNF-α. All these molecules were increased in HFD mice compared to the SD group. We also evaluated anti-inflammatory molecules like adiponectin, adiponectin receptor, and PPAR-γ, and observed their significant reduction in the HFD w/Suc group compared to the control. Our data are in line with the knowledge that improper eating habits present a primary harmful assault on the bowel and the entire body's health. (4) These results represent a promising starting point for future studies, helping to better understand the complex and not fully elucidated spectrum of intestinal alterations induced by the overconsumption of fat.

Computed Tomography-Derived Myosteatosis and Metabolic Disorders

The role of ectopic adipose tissue infiltration into skeletal muscle (i.e., myosteatosis) for metabolic disorders has received considerable and increasing attention in the last 10 years. The purpose of this review was to evaluate and summarize existing studies focusing on computed tomography (CT)-derived measures of myosteatosis and metabolic disorders. There is consistent evidence that CT-derived myosteatosis contributes to dysglycemia, insulin resistance, type 2 diabetes mellitus, and inflammation, and, to some extent, dyslipidemia, independent of general obesity, visceral fat, and other relevant risk factors, suggesting that it may serve as a tool for metabolic risk prediction. Identification of which muscles should be examined, and the standardized CT protocols to be employed, are necessary to enhance the applicability of findings from epidemiologic studies of myosteatosis. Additional and longer longitudinal studies are necessary to confirm a role of myosteatosis in the development of type 2 diabetes mellitus, and examine these associations in a variety of muscles across multiple race/ethnic populations. Given the emerging role of myosteatosis in metabolic health, well-designed intervention studies are needed to investigate relevant lifestyle and pharmaceutical approaches.

Hemostatic alterations linked to body fat distribution, fatty liver, and insulin resistance

OBJECTIVE

Obesity, in particular visceral obesity, and insulin resistance emerged as major risk factors for severe coronavirus disease 2019 (COVID-19), which is strongly associated with hemostatic alterations. Because obesity and insulin resistance predispose to thrombotic diseases, we investigated the relationship between hemostatic alterations and body fat distribution in participants at risk for type 2 diabetes.

SUBJECTS

Body fat distribution (visceral and subcutaneous abdominal adipose tissue) and liver fat content of 150 participants - with impaired glucose tolerance and/or impaired fasting glucose - were determined using magnetic resonance imaging and spectroscopy. Participants underwent precise metabolic characterization and major hemostasis parameters were analyzed.

RESULTS

Procoagulant factors (FII, FVII, FVIII, and FIX) and anticoagulant proteins (antithrombin, protein C, and protein S) were significantly associated with body fat distribution. In patients with fatty liver, fibrinogen (298 mg/dl vs. 264 mg/dl, p = 0.0182), FVII (99% vs. 90%, p = 0.0049), FVIII (114% vs. 90%, p = 0.0098), protein C (124% vs. 111%, p = 0.0006), and protein S (109% vs. 89%, p < 0.0001) were higher than in controls. In contrast, antithrombin (97% vs. 102%, p = 0.0025) was higher in control patients. In multivariate analyses controlling for insulin sensitivity, body fat compartments, and genotype variants (PNPLA3^I148MM/MI/TM6SF2^E167kK/kE), only protein C and protein S remained significantly increased in fatty liver.

CONCLUSIONS

Body fat distribution is significantly associated with alterations of procoagulant and anticoagulant parameters. Liver fat plays a key role in the regulation of protein C and protein S, suggesting a potential counteracting mechanism to the prothrombotic state in subjects with prediabetes and fatty liver.

Fermentation of Chestnut (Catanea crenata Sieb) Inner Shell Enhances Anti-Obesity Effects in 3T3-L1 and C3H10T1/2 Adipocytes

Chestnut inner shell (CIS) is rich in phenols and flavonoids such as gallic acid and ellagic acid, which are known to exhibit effective antioxidant and anti-obesity properties. Fermentation using lactic acid bacteria can enhance the physiological activity by increasing the contents of such functional ingredients. In this study, we evaluated the anti-obesity effects of a CIS extract subjected to a fermentation process (fermented CIS [FCIS]). Treatment with CIS and FCIS extracts (125, 250, and 500 μg/mL) increased cell viability and did not induce apoptosis, indicating no toxicity. The extract suppressed the gene expression of adipogenic factors, peroxisome proliferation-activated receptor gamma, CCAAT/enhancer binding protein (C/EBP) alpha, and C/EBP beta (by 7.75% and 67.59%, 21.41% and 66.27% in 500 μg/mL, respectively), and consequently suppressed the expression of downstream lipogenic factors such as fatty acid synthase, stearoyl CoA desaturase-1, citrate synthase, and ATP citrate lyase. The expression of factors involved in fat catabolism and β-oxidation increased in a dose-dependent manner, thereby preventing fat accumulation. This observation was consistent with the significant decrease in the staining intensity for lipid droplets, which indicated that lipid accumulation was decreased by 15.46% and 29.44% in 3T3L-1 and 27.01% and 46.68% in C3H10T1/2. Together, these results demonstrate the higher anti-obesity effects of FCIS extract than that of CIS extract, indicating the potential applicability of FCIS as an effective natural raw material to curb obesity.

Can We Decrease Epicardial and Pericardial Fat in Patients With Diabetes?

Diabetes mellitus (DM) is a chronic and complex metabolic disorder and also an important cause of cardiovascular (CV) disease (CVD). Patients with type 2 DM (T2DM) and obesity show a greater propensity for visceral fat deposition (and excessive fat deposits elsewhere) and the link between adiposity and CVD risk is greater for visceral than for subcutaneous (SC) adipose tissue (AT). There is growing evidence that epicardial AT (EAT) and pericardial AT (PAT) play a role in the development of DM-related atherosclerosis, atrial fibrillation (AF), myocardial dysfunction, and heart failure (HF). In this review, we will highlight the importance of PAT and EAT in patients with DM. We also consider therapeutic interventions that could have a beneficial effect in terms of reducing the amount of AT and thus CV risk. EAT is biologically active and a likely determinant of CV morbidity and mortality in patients with DM, given its anatomical characteristics and proinflammatory secretory pattern. Consequently, modification of EAT/PAT may become a therapeutic target to reduce the CV burden. In patients with DM, a low calorie diet, exercise, antidiabetics and statins may change the quantity of EAT, PAT or both, alter the secretory pattern of EAT, improve the metabolic profile, and reduce inflammation. However, well-designed studies are needed to clearly define CV benefits and a therapeutic approach to EAT/PAT in patients with DM.

Obesity considerations during the COVID-19 outbreak

The worldwide population is facing a double burden of epidemic, the COVID-19 and obesity. This is even more alarming as obesity increases the COVID-19 severity. However, the relationship between obesity and COVID-19 severity is more complex than a simple association with BMI. In particular, obesity has been associated with low death rates in patients with acute respiratory distress syndrome, a fatal comorbidity to COVID-19, possibly due to the obesity paradox. Also, visceral adiposity could be a major risk factor for COVID-19 severity, due to its immune activation component, release of angiotensin-converting enzyme 2 and involvement in the cytokine storm, hypercoagulability and embolism. A poor antioxidant nutritional status also weakens the immune system, increasing inflammation and infection risk. Moreover, the COVID-19 lockdown might impact lifestyle patterns, mental health and weight bias, worsening the obesity then COIVD-19 situation. On the other hand, health care expenses and productivity loss are expected to increase during the concomitant epidemics. The co-occurrence of obesity and COVID-19 is a major challenge at both public health and economic levels that should urgently be taken into consideration. The identification of COVID-19 weight related risk factors and the development of appropriate weight management programs are needed to tackle the concomitant epidemics.

Neck Circumference and 10-Year Cardiovascular Risk at the Baseline of the ELSA-Brasil Study: Difference by Sex

Fundamento:

A circunferência do pescoço (CP) é uma medida indireta do tecido adiposo subcutâneo da parte superior do corpo, apontada como um preditor independente de doenças cardiometabólicas.

Objetivos:

Verificar a associação entre a CP e o risco cardiovascular em 10 anos (risco de doença cardiovascular [DCV] em 10 anos) em homens e mulheres separadamente.

Métodos:

Análise seccional com inclusão de 13.920 participantes da linha de base do Estudo Longitudinal da Saúde do Adulto (ELSA-Brasil). A associação entre a CP (utilizada como variável contínua e agregada em quartis) e o risco de DCV em 10 anos, estimado pelo Framingham Global Risk Score (FGRS), foi investigada por meio de modelos lineares generalizados após ajustes por características sociodemográficas, comportamentos em saúde, índice de massa corporal e circunferência da cintura. O nível de significância estatístico adotado foi de 5%.

Resultados:

A média da CP foi de 39,5 cm (desvio-padrão [DP] de ± 3,6) nos homens e 34,0 cm (DP de ±2,9) nas mulheres. Após ajustes, o aumento de 1 cm na CP foi associado ao incremento de 3% (IC 95%: 1,02 a 1,03) e 5% (IC 95%: 1,04 a 1,06) na média aritmética do risco de DCV em homens e mulheres, respectivamente. No último quartil da CP, homens e mulheres apresentaram um incremento de 18% (IC 95%: 1,13 a 1,24) e 35% (IC 95%: 1,28 a 1,43), respectivamente, na média aritmética do risco de DCV após ajustes.

Conclusões:

Verificamos associação positiva e independente entre a CP e o risco de DCV em 10 anos. Resultados sugerem que a CP pode contribuir para a predição de risco cardiovascular além daquele observado pelas medidas antropométricas clássicas.

The association between triglycerides and ectopic fat obesity: An inverted U-shaped curve

Background

Ectopic fat obesity and triglycerides are risk factors for diabetes and multiple cardiovascular diseases. However, there have been limited studies on the association between triglycerides and ectopic fat obesity. The purpose of this study was to explore the association between triglycerides and ectopic fat obesity.

Methods and results

In this cross-sectional study, we retrospectively analyzed 15464 adult participants recruited by Murakami Memorial Hospital (8430 men and 7034 women, average age of 43.71 ± 8.90). All patients were divided into two groups according to the threshold used to diagnose hypertriglyceridemia. The logistic regression model was used to analyze the association between triglycerides and the risk of ectopic fat obesity, and the generalized additive model was used to identify the nonlinear association. In this study population, the prevalence of ectopic fat obesity was 17.73%. After adjusting other covariables, triglycerides were positively correlated with the risk of ectopic fat obesity (OR: 1.54, 95% CI:1.41–1.69, P<0.0001). Through smooth curve fitting, we found that there was an inverted U-shaped curve association between triglycerides and ectopic fat obesity. This association remained unchanged even if the adjusted covariables were removed from the model, and the inflection point of the curve was 3.98. When triglyceride levels were ≤3.98, triglycerides were positively correlated with the risk of ectopic fat obesity (OR:1.784, 95% CI:1.611–1.975, P<0.0001). When triglyceride levels were >3.98 (right side of the inflection point), there was a negative correlation (OR:0.519, 95% CI:0.333–0.810, P = 0.0039).

Conclusions

Our research showed that there is a significant association between triglycerides and ectopic fat obesity. This relation is not a simple linear relationship but instead an inverted U-shaped curve association.

The Effect of a Novel Low-Volume Aerobic Exercise Intervention on Liver Fat in Type 2 Diabetes: A Randomized Controlled Trial

OBJECTIVE

The aim of this study was to examine the effect of a novel low-volume high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), or placebo (PLA) intervention on liver fat, glycemia, and cardiorespiratory fitness using a randomized placebo-controlled design.

RESEARCH DESIGN AND METHODS

Thirty-five inactive adults (age 54.6 ± 1.4 years, 54% male; BMI 35.9 ± 0.9 kg/m²) with obesity and type 2 diabetes were randomized to 12 weeks of supervised MICT (n = 12) at 60% VO_2peak for 45 min, 3 days/week; HIIT (n = 12) at 90% VO_2peak for 4 min, 3 days/week; or PLA (n = 11). Liver fat percentage was quantified through proton MRS.

RESULTS

Liver fat reduced in MICT (-0.9 ± 0.7%) and HIIT (-1.7 ± 1.1%) but increased in PLA (1.2 ± 0.5%) (P = 0.046). HbA_1c improved in MICT (-0.3 ± 0.3%) and HIIT (-0.3 ± 0.3%) but not in PLA (0.5 ± 0.2%) (P = 0.014). Cardiorespiratory fitness improved in MICT (2.3 ± 1.2 mL/kg/min) and HIIT (1.1 ± 0.5 mL/kg/min) but not in PLA (-1.5 ± 0.9 mL/kg/min) (P = 0.006).

CONCLUSIONS

MICT or a low-volume HIIT approach involving 12 min of weekly high-intensity aerobic exercise may improve liver fat, glycemia, and cardiorespiratory fitness in people with type 2 diabetes in the absence of weight loss. Further studies are required to elucidate the relationship between exercise-induced reductions in liver fat and improvements in glycemia.

Relationship of oxidative stress to visceral adiposity in youth and role played by vitamin D

BACKGROUND

Visceral adipose tissue (VAT) accumulation is a major cardiometabolic risk factor, associated with increased inflammation. Oxidative stress (OS) is also associated with inflammation and cardiometabolic issues, yet mainly through general obesity. Both OS and obesity were linked to vitamin D deficiency.

OBJECTIVES

To investigate whether OS increase is associated with VAT accumulation in youth, and whether in the presence of VAT accumulation, a higher vitamin D status is associated with lower OS.

METHODS

One hundred and fifty-eight youth with overweight/obesity, 7 to 17 years old, were recruited (Pediatric Clinic, Luxembourg). We assessed visceral and subcutaneous abdominal adipose tissues by magnetic resonance imaging, OS by DNA/RNA oxidative damage with ELISA and vitamin D by high-performance liquid chromatography.

RESULTS

VAT was the body fat compartment the most strongly associated with OS (R_Pearson : 0.298; P < 10^-4 ). The general linear (GLM) models assessing the relationship between OS, VAT and vitamin D concentrations showed that "Log₁₀ OS = (0.003 × VAT) + 3.911 (R²_adjusted : 0.083; P-value < 10^-4 )"; "Log₁₀ OS = (0.003 × VAT) - (0.156 × log₁₀ vitamin D) + 4.110 (R²_adjusted : 0.101; P-value < 10^-4 )". After back-transformation of the log-values into normal values, the GLM showed that, for a person with an average value of VAT (40.7 cm² ), a 10 cm² increase in VAT would increase OS by approx. 771.833 pg/mL, after age, gender, Tanner stage and physical activity adjustment. An approximate increase of 9 ng/mL of vitamin D would counterbalance this negative effect of increased VAT.

CONCLUSION

Dietary strategies improving vitamin D status should be investigated to tackle VAT and OS increase.

Hepatic and Skeletal Muscle Adiposity Are Associated with Diabetes Independent of Visceral Adiposity in Nonobese African-Caribbean Men

Background: Adipose tissue (AT) around and within non-AT organs (i.e., ectopic adiposity) is emerging as a strong risk factor for type 2 diabetes (T2D). Not known is whether major ectopic adiposity depots, such as hepatic, skeletal muscle, and pericardial adiposity (PAT), are associated with T2D independent of visceral adiposity (VAT). More data are particularly needed among high-risk nonobese minority populations, as the race/ethnic gap in T2D risk is greatest among nonobese. Methods: Thus, we measured several ectopic adiposity depots by computed tomography in 718 (mean age = 64 years) African-Caribbean men on the Island of Tobago overall, and stratified by obesity (obese N = 187 and nonobese N = 532). Results: In age, lifestyle risk factors, health status, lipid-lowering medication intake, body mass index and all other adiposity-adjusted regression analyses, and hepatic and skeletal muscle adiposity were associated with T2D among nonobese men only (all P < 0.05), despite no association between VAT and PAT and T2D. Conclusions: Our results support the "ectopic fat syndrome" theory in the pathogenesis of T2D among nonobese African-Caribbean men. Longitudinal studies are needed to clarify the independent role of ectopic adiposity in T2D, and to identify possible biological mechanisms underlying this relationship, particularly in high-risk African ancestry and other nonwhite populations.

Review: the Roles and Mechanisms of Glycoprotein 130 Cytokines in the Regulation of Adipocyte Biological Function

Chronic low-grade inflammation is now widely accepted as one of the most important contributors to metabolic disorders. Glycoprotein 130 (gp130) cytokines are involved in the regulation of metabolic activity. Studies have shown that several gp130 cytokines, such as interleukin-6 (IL-6), leukemia inhibitory factor (LIF), oncostatin M (OSM), ciliary neurotrophic factor (CNTF), and cardiotrophin-1 (CT-1), have divergent effects on adipogenesis, lipolysis, and insulin sensitivity as well as food intake. In this review, we will summarize the present knowledge about gp130 cytokines, including IL-6, LIF, CNTF, CT-1, and OSM, in adipocyte biology and metabolic activities in conditions such as obesity, cachexia, and type 2 diabetes. It is valuable to explore the diverse actions of these gp130 cytokines on the regulation of the biological functions of adipocytes, which will provide potential therapeutic targets for the treatment of obesity and cachexia.

Dietary Apigenin promotes lipid catabolism, thermogenesis, and browning in adipose tissues of HFD-Fed mice

Dietary Apigenin (AP), a natural flavonoid from plants, could alleviate high-fat diet (HFD) induced obesity and its complication. Nonetheless, the direct correlation between dietary AP and their effects in adipose tissues remained unclear. In this study, male C57BL/6 mice were fed with low-fat diet, HFD with or without 0.04% (w/w) AP for 12 weeks. Dietary AP ameliorated HFD induced body weight gain, glucose intolerance, and insulin resistance. Energy expenditure was increased with no influence on energy intake, which indicated us that AP prevented obesity by enhancing energy export. Interestingly, AP activated lipolysis (ATGL/FOXO1/SIRT1) without higher cycling free fatty acids (FFAs). FFAs were consumed by the upregulation of fatty acid oxidation (AMPK/ACC), thermogenesis, and browning (UCP-1, PGC-1α). Additionally, adipose tissue metabolic inflammation (NF-кB, MAPK) was also reduced by AP. Our study proposed that dietary AP could be explored as a new dietary strategy to combat obesity and related insulin resistance.

From syndrome X to cardiometabolic risk: clinical and public health implications

Although the first description of a syndrome defined by the co-existence of atherogenic and diabetogenic metabolic abnormalities is debated in the literature, it was Gerald Reaven who proposed, in his landmark 1988 Banting award lecture, that a significant proportion of individuals (with diabetes or not) were characterised by insulin resistance causing prejudice to cardiovascular health. However, Reaven was influenced by seminal observations made more than 50 years earlier by Himsworth who proposed that there were two forms of diabetes (insulin resistant v. insulin sensitive). Reaven went further in proposing the theory that insulin resistance was the most prevalent cause of CVD associated with metabolic abnormalities that he named syndrome X. Because there was a syndrome X documented in cardiology, the term evolved to insulin resistance syndrome. As Reaven could also find insulin-resistant individuals in non-obese subjects, he did not include obesity as a feature of syndrome X. Imaging studies then revealed that excess adipose tissue in the abdominal cavity, a condition described as visceral obesity, was the form of overweight/obesity associated with insulin resistance and its related abnormalities. As obesity risk assessment and management remain largely based on body weight (BMI) and weight loss, it is proposed that our clinical approaches and public health messages should be revisited. First, patients should be educated about the importance of monitoring their waistline as a crude index of abdominal adiposity. Secondly, public health approaches focussing on 'lifestyle vital signs' including achieving healthy waistlines rather than healthy body weights should be developed.

Effects of Dietary Protein and Fat Content on Intrahepatocellular and Intramyocellular Lipids during a 6-Day Hypercaloric, High Sucrose Diet: A Randomized Controlled Trial in Normal Weight Healthy Subjects

Sucrose overfeeding increases intrahepatocellular (IHCL) and intramyocellular (IMCL) lipid concentrations in healthy subjects. We hypothesized that these effects would be modulated by diet protein/fat content. Twelve healthy men and women were studied on two occasions in a randomized, cross-over trial. On each occasion, they received a 3-day 12% protein weight maintenance diet (WM) followed by a 6-day hypercaloric high sucrose diet (150% energy requirements). On one occasion the hypercaloric diet contained 5% protein and 25% fat (low protein-high fat, LP-HF), on the other occasion it contained 20% protein and 10% fat (high protein-low fat, HP-LF). IHCL and IMCL concentrations (magnetic resonance spectroscopy) and energy expenditure (indirect calorimetry) were measured after WM, and again after HP-LF/LP-HF. IHCL increased from 25.0 ± 3.6 after WM to 147.1 ± 26.9 mmol/kg wet weight (ww) after LP-HF and from 30.3 ± 7.7 to 57.8 ± 14.8 after HP-LF (two-way ANOVA with interaction: p < 0.001 overfeeding x protein/fat content). IMCL increased from 7.1 ± 0.6 to 8.8 ± 0.7 mmol/kg ww after LP-HF and from 6.2 ± 0.6 to 6.9 ± 0.6 after HP-LF, (p < 0.002). These results indicate that liver and muscle fat deposition is enhanced when sucrose overfeeding is associated with a low protein, high fat diet compared to a high protein, low fat diet.

Impaired Adipogenesis and Dysfunctional Adipose Tissue in Human Hypertrophic Obesity

The subcutaneous adipose tissue (SAT) is the largest and best storage site for excess lipids. However, it has a limited ability to expand by recruiting and/or differentiating available precursor cells. When inadequate, this leads to a hypertrophic expansion of the cells with increased inflammation, insulin resistance, and a dysfunctional prolipolytic tissue. Epi-/genetic factors regulate SAT adipogenesis and genetic predisposition for type 2 diabetes is associated with markers of an impaired SAT adipogenesis and development of hypertrophic obesity also in nonobese individuals. We here review mechanisms for the adipose precursor cells to enter adipogenesis, emphasizing the role of bone morphogenetic protein-4 (BMP-4) and its endogenous antagonist gremlin-1, which is increased in hypertrophic SAT in humans. Gremlin-1 is a secreted and a likely important mechanism for the impaired SAT adipogenesis in hypertrophic obesity. Transiently increasing BMP-4 enhances adipogenic commitment of the precursor cells while maintained BMP-4 signaling during differentiation induces a beige/brown oxidative phenotype in both human and murine adipose cells. Adipose tissue growth and development also requires increased angiogenesis, and BMP-4, as a proangiogenic molecule, may also be an important feedback regulator of this. Hypertrophic obesity is also associated with increased lipolysis. Reduced lipid storage and increased release of FFA by hypertrophic SAT are important mechanisms for the accumulation of ectopic fat in the liver and other places promoting insulin resistance. Taken together, the limited expansion and storage capacity of SAT is a major driver of the obesity-associated metabolic complications.

Differential role of insulin resistance and β-cell function in the development of prediabetes and diabetes in middle-aged and elderly Chinese population

BACKGROUND

The prevalence of diabetes and prediabetes were estimated to be 10.9% and 35.7% in the Chinese adult population, respectively, and the middle-aged and elderly Chinese are at even higher risk of diabetes and prediabetes than younger population. With the increasing trend of aging in China, the burden of diabetes and related complications will be aggravated.

OBJECTIVES

Through comparing the indices of insulin resistance and β-cell function between subjects with different glucose metabolic status, to analyze the differential role of insulin resistance and β-cell function in the development of prediabetes and type 2 diabetes (T2DM) in the middle-aged and elderly Chinese population.

METHODS

In this cross-sectional study, we enrolled 512 participants aged 50 and over. The indices of insulin resistance (homoeostasis model assessment of insulin resistance (HOMA-IR) and adipose tissue insulin resistance (Adipo-IR), and indices of β-cell function [HOMA-β), fasting C-peptide to glucose ratio (FCPRI) and postprandial C-peptide to glucose ratio (PCPRI)] were calculated. Association of insulin resistance and β-cell function with prediabetes or T2DM were evaluated by multivariate logistic regression analysis, in which potential confounding factors were adjusted.

RESULTS

Of the 509 participants with complete information, 263 (51.7%) had normal glucose tolerance (NGT), 161 (31.6%) were in prediabetic status and 85 (16.7%) were overt T2DM. With the advancing of unfavorable glucose metabolism, the insulin resistance (HOMA-IR and Adipo-IR) and β-cell function (FCPRI, PCPRI) deteriorated (P _trend < 0.05 for all indices). We found that increase in insulin resistance expressed by Adipo-IR and HOMA-IR is associated with increased risk of prediabetes, whereas decrease in β-cell function expressed by HOMA-β and PCPRI is associated with increased risk of T2DM. We also demonstrated that Adipo-IR was more closely associated with developing prediabetes than HOMA-IR, and PCPRI was most closely related with developing T2DM among the indices of β-cell function used in this study.

CONCLUSIONS

Insulin resistance is the main determinant of developing prediabetes, whereas β-cell function is the main determinant of developing T2DM.

“Obesity paradoxes”: main causes of an “inverse” cardiovascular epidemiology

Taken the continuous increase of obesity prevalence, most countries in the world deal with an epidemy, one of the main healthcare concerns. In the structure of nosology associated with overweight and obesity, cardiovascular is leading. Also, in the recent trials and meta analyses there is negative correlation found for body mass index and clinical outcomes characterizing better survival and lower events rate in those with higher BMI, as less chronic diseases. Such facts facilitated a number of discussions on the predictive value of overweight and obesity and consideration whether to correct those in cardiovascular patients as secondary prevention. Current article is focused on the main causes for an “inverse” cardiovascular epidemiology in overweight and obesity.

Fenugreek (Trigonella Foenum-Graecum) Seed Flour and Diosgenin Preserve Endothelium-Dependent Arterial Relaxation in a Rat Model of Early-Stage Metabolic Syndrome

Fenugreek is a common herb possessing several bioactive components including diosgenin. Here, dietary fenugreek seed flour and diosgenin were evaluated on a model of endothelium-dependent vasorelaxation by abdominal aortas isolated from rats receiving high-fat, high-sugar diet (HFHSD). 60 male Wistar rats were randomized into six groups: (i) negative control getting conventional rat feed regimen; (ii) positive control receiving HFHSD; (iii) a test group fed 2 g/kg bw/day fenugreek seed flour (containing 10 mg/kg bw/day diosgenin) + HFHSD; (iv) three test groups fed 1, 10 and 50 mg/kg bw/day diosgenin + HFHSD. Alimentary treatments were carried out for six weeks. The abdominal aortas were isolated, and 2 mm wide rings were sectioned off and mounted at a resting tension of 10 mN in organ baths containing Krebs solution (36 °C) exposed to 95% O₂ and 5% CO₂. After 60-min incubation, a norepinephrine concentration-response (E/c) curve was generated to determine their half-maximal effective concentration (EC₅₀) value. After 60-min wash-out, a pre-contraction with norepinephrine EC₅₀ was made, followed by an acetylcholine E/c curve. Plasma glutathione levels, glutathione-handling enzyme activities and blood antioxidant capacities were also determined. HFHSD significantly decreased the dilatory response to acetylcholine and increased plasma glutathione levels and these effects were significantly reversed by fenugreek seed flour, 10 and 50 mg/kg bw/day diosgenin. Both fenugreek and diosgenin treatments prevent HFHSD-induced endothelial dysfunction and redox changes. As fenugreek treatment was more effective at lower acetylcholine concentrations than diosgenin treatments, components of fenugreek other than diosgenin may contribute to the beneficial effects of dietary fenugreek seed flour.

Atherothrombosis and Thromboembolism: Position Paper from the Second Maastricht Consensus Conference on Thrombosis

Atherothrombosis is a leading cause of cardiovascular mortality and long-term morbidity. Platelets and coagulation proteases, interacting with circulating cells and in different vascular beds, modify several complex pathologies including atherosclerosis. In the second Maastricht Consensus Conference on Thrombosis, this theme was addressed by diverse scientists from bench to bedside. All presentations were discussed with audience members and the results of these discussions were incorporated in the final document that presents a state-of-the-art reflection of expert opinions and consensus recommendations regarding the following five topics: 1. Risk factors, biomarkers and plaque instability: In atherothrombosis research, more focus on the contribution of specific risk factors like ectopic fat needs to be considered; definitions of atherothrombosis are important distinguishing different phases of disease, including plaque (in)stability; proteomic and metabolomics data are to be added to genetic information. 2. Circulating cells including platelets and atherothrombosis: Mechanisms of leukocyte and macrophage plasticity, migration, and transformation in murine atherosclerosis need to be considered; disease mechanism-based biomarkers need to be identified; experimental systems are needed that incorporate whole-blood flow to understand how red blood cells influence thrombus formation and stability; knowledge on platelet heterogeneity and priming conditions needs to be translated toward the in vivo situation. 3. Coagulation proteases, fibrin(ogen) and thrombus formation: The role of factor (F) XI in thrombosis including the lower margins of this factor related to safe and effective antithrombotic therapy needs to be established; FXI is a key regulator in linking platelets, thrombin generation, and inflammatory mechanisms in a renin-angiotensin dependent manner; however, the impact on thrombin-dependent PAR signaling needs further study; the fundamental mechanisms in FXIII biology and biochemistry and its impact on thrombus biophysical characteristics need to be explored; the interactions of red cells and fibrin formation and its consequences for thrombus formation and lysis need to be addressed. Platelet-fibrin interactions are pivotal determinants of clot formation and stability with potential therapeutic consequences. 4. Preventive and acute treatment of atherothrombosis and arterial embolism; novel ways and tailoring? The role of protease-activated receptor (PAR)-4 vis à vis PAR-1 as target for antithrombotic therapy merits study; ongoing trials on platelet function test-based antiplatelet therapy adjustment support development of practically feasible tests; risk scores for patients with atrial fibrillation need refinement, taking new biomarkers including coagulation into account; risk scores that consider organ system differences in bleeding may have added value; all forms of oral anticoagulant treatment require better organization, including education and emergency access; laboratory testing still needs rapidly available sensitive tests with short turnaround time. 5. Pleiotropy of coagulation proteases, thrombus resolution and ischaemia-reperfusion: Biobanks specifically for thrombus storage and analysis are needed; further studies on novel modified activated protein C-based agents are required including its cytoprotective properties; new avenues for optimizing treatment of patients with ischaemic stroke are needed, also including novel agents that modify fibrinolytic activity (aimed at plasminogen activator inhibitor-1 and thrombin activatable fibrinolysis inhibitor.

The color of fat and its central role in the development and progression of metabolic diseases

Excess caloric intake does not always translate to an expansion of the subcutaneous adipose tissue (SAT) and increase in fat mass. It is now recognized that adipocyte type (white, WAT, or brown, BAT), size (large vs. small) and metabolism are important factors for the development of cardiometabolic diseases. When the subcutaneous adipose tissue is not able to expand in response to increased energy intake the excess substrate is stored as visceral adipose tissue or as ectopic fat in tissues as muscle, liver and pancreas. Moreover, adipocytes become dysfunctional (adiposopathy, or sick fat), adipokines secretion is increased, fat accumulates in ectopic sites like muscle and liver and alters insulin signaling, increasing the demand for insulin secretion. Thus, there are some subjects that despite having normal weight have the metabolic characteristics of the obese (NWMO), while some obese expand their SAT and remain metabolically healthy (MHO). In this paper we have reviewed the recent findings that relate the metabolism of adipose tissue and its composition to metabolic diseases. In particular, we have discussed the possible role of dysfunctional adipocytes and adipose tissue resistance to the antilipolytic effect of insulin on the development of impaired glucose metabolism. Finally we have reviewed the possible role of BAT vs. WAT in the alteration of lipid and glucose metabolism and the recent studies that have tried to stimulate browning in human adipose tissue.

Lack of NLRP3-inflammasome leads to gut-liver axis derangement, gut dysbiosis and a worsened phenotype in a mouse model of NAFLD

Non-Alcoholic Fatty Liver Disease (NAFLD) represents the most common form of chronic liver injury and can progress to cirrhosis and hepatocellular carcinoma. A "multi-hit" theory, involving high fat diet and signals from the gut-liver axis, has been hypothesized. The role of the NLRP3-inflammasome, which senses dangerous signals, is controversial. Nlrp3-/- and wild-type mice were fed a Western-lifestyle diet with fructose in drinking water (HFHC) or a chow diet. Nlrp3-/--HFHC showed higher hepatic expression of PPAR γ2 (that regulates lipid uptake and storage) and triglyceride content, histological score of liver injury and greater adipose tissue inflammation. In Nlrp3-/--HFHC, dysregulation of gut immune response with impaired antimicrobial peptides expression, increased intestinal permeability and the occurrence of a dysbiotic microbiota led to bacterial translocation, associated with higher hepatic expression of TLR4 (an LPS receptor) and TLR9 (a receptor for double-stranded bacterial DNA). After antibiotic treatment, gram-negative species and bacterial translocation were reduced, and adverse effects restored both in liver and adipose tissue. In conclusion, the combination of a Western-lifestyle diet with innate immune dysfunction leads to NAFLD progression, mediated at least in part by dysbiosis and bacterial translocation, thus identifying new specific targets for NAFLD therapy.

Role of Adipose Tissue Insulin Resistance in the Natural History of Type 2 Diabetes: Results From the San Antonio Metabolism Study

In the transition from normal glucose tolerance (NGT) to type 2 diabetes mellitus (T2DM), the role of β-cell dysfunction and peripheral insulin resistance (IR) is well established. However, the impact of dysfunctional adipose tissue has not been fully elucidated. The aim of this study was to evaluate the role of resistance to the antilipolytic effect of insulin (adipose tissue IR [Adipo-IR]) in a large group of subjects with NGT, impaired glucose tolerance (IGT), and T2DM. Three hundred two subjects with varying glucose tolerance received an oral glucose tolerance test (OGTT) and euglycemic insulin clamp. We evaluated Adipo-IR (fasting and mean OGTT plasma free fatty acid [FFA] × insulin concentrations), peripheral IR (1/[Matsuda index] and (M/I)^-1 value), and β-cell function (calculated as the ratio of the increment in plasma insulin to glucose [OGTT/IR (ΔI/ΔG ÷ IR)]). Fasting Adipo-IR was increased twofold in obese subjects with NGT and IGT versus lean subjects with NGT (8.0 ± 1.1 and 9.2 ± 0.7 vs. 4.1 ± 0.3, respectively) and threefold in subjects with T2DM (11.9 ± 0.6; P < 0.001). Progressive decline in ΔI/ΔG ÷ IR was associated with a progressive impairment in FFA suppression during OGTT, whereas the rise in mean plasma glucose concentration only became manifest when subjects became overtly diabetic. The progressive decline in β-cell function that begins in individuals with NGT is associated with a progressive increase in FFA and fasting Adipo-IR.

The contribution of different adipose tissue depots to plasma plasminogen activator inhibitor-1 (PAI-1) levels

Increased plasma plasminogen activator inhibitor-1 (PAI-1) level is considered a mechanistic pathway through which obesity contributes to increased cardiovascular disease risk. Abdominal adipose tissue specifically, is a major PAI-1 source with visceral adipose tissue (VAT), an ectopic fat depot, generally considered to produce more PAI-1 than subcutaneous adipose tissue. However, this does not necessarily lead to increased plasma PAI-1 levels. This review provides an overview of studies investigating the association between body fat distribution and plasma PAI-1 levels. It discusses factors that influence this relationship and also considers the contribution of other tissue to plasma PAI-1 levels, placing the relative contribution of adipose tissue into perspective. In conclusion, the relationship between VAT and plasma PAI-1 levels is not fixed but can be modulated by a number of factors such as the size of the subcutaneous adipose tissue depot, ethnicity, possibly genetics and other obesity-related metabolic abnormalities.

Clinical Presentation and Patient Evaluation in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a diagnosis of exclusion. Most patients are asymptomatic and diagnosed incidentally. Most patients remain undiagnosed. A high index of suspicion and serologic work-up to rule out alternative causes of liver disease is required. In NALFD, fibrosis correlates with outcomes, including mortality. To diagnose, assess severity, and monitor fibrosis, 2 noninvasive methods can be used. However, noninvasive tests are more helpful at extremes of fibrosis: excluding it or diagnosing advanced fibrosis. Liver biopsy is usually reserved for cases whereby noninvasive tests fail to accurately determine the degree of fibrosis or the diagnosis is unclear.

The Subtle Balance between Lipolysis and Lipogenesis: A Critical Point in Metabolic Homeostasis

Excessive accumulation of lipids can lead to lipotoxicity, cell dysfunction and alteration in metabolic pathways, both in adipose tissue and peripheral organs, like liver, heart, pancreas and muscle. This is now a recognized risk factor for the development of metabolic disorders, such as obesity, diabetes, fatty liver disease (NAFLD), cardiovascular diseases (CVD) and hepatocellular carcinoma (HCC). The causes for lipotoxicity are not only a high fat diet but also excessive lipolysis, adipogenesis and adipose tissue insulin resistance. The aims of this review are to investigate the subtle balances that underlie lipolytic, lipogenic and oxidative pathways, to evaluate critical points and the complexities of these processes and to better understand which are the metabolic derangements resulting from their imbalance, such as type 2 diabetes and non alcoholic fatty liver disease.

Notch signaling pathway activation in normal and hyperglycemic rats differs in the stem cells of visceral and subcutaneous adipose tissue

The precise mechanisms underlying the differential function and cardiometabolic risk of white adipose tissue (WAT) remain unclear. Visceral adipose tissue (VWAT) and subcutaneous adipose tissue (SCWAT) have different metabolic functions that seem to be ascribed to their different intrinsic expansion capacities. Here we have hypothesized that the WAT characteristics are determined by the resident adipose-derived stem cells (ASCs) found in the different WAT depots. Therefore, our objective has been to investigate adipogenesis in anatomically distinct fat depots. ASCs from five different WAT depots were characterized in both healthy lean and diabetic obese rats, showing significant differences in expression of some of genes governing the stemness and the earlier adipogenic differentiation steps. Notch-target genes [Hes (hairy and enhancer of split) and Hey (hairy/enhancer of split related with YRPW motif) families] were upregulated in ASCs derived from visceral depots. Upon adipogenic differentiation, adipocyte cell markers were downregulated in ASCs from VWAT in comparison to ASCs from SCWAT, revealing a lower adipogenic capacity in ASCs of visceral origin than in those of SCWAT in accordance with the differential activation of Notch signaling. Notch upregulation by its activator phenethyl isothiocyanate attenuated the adipogenic differentiation of ASCs from SCWAT whereas Notch inhibition by N-[N-(3,5-difluorophenacetyl-L-alanyl)]-S-phenylglycine t-butyl ester (DAPT) increased the adipogenic differentiation of ASCs from visceral origin. In conclusion, the differential activation of Notch in ASCs is the origin of the different intrinsic WAT expansion capacities that contribute to the regional variations in WAT homeostasis and to its associated cardiometabolic risk.

HORMONE MEASUREMENT GUIDELINES: Tracing lipid metabolism: the value of stable isotopes

Labelling molecules with stable isotopes to create tracers has become a gold-standard method to study the metabolism of lipids and lipoproteins in humans. There are a range of techniques which use stable isotopes to measure fatty acid flux and oxidation, hepatic fatty synthesis, cholesterol absorption and synthesis and lipoprotein metabolism in humans. Stable isotope tracers are safe to use, enabling repeated studies to be undertaken and allowing studies to be undertaken in children and pregnant women. This review provides details of the most appropriate tracers to use, the techniques which have been developed and validated for measuring different aspects of lipid metabolism and some of the limitations of the methodology.

Anti-Obesity Effects of the Mixture of Eriobotrya japonica and Nelumbo nucifera in Adipocytes and High-Fat Diet-Induced Obese Mice

The present study is to evaluate the anti-obesity effects of Eriobotrya japonica (EJ), Nelumbo nucifera (NN), and their mixture (MIX, 1:1 ratio) in 3T3-L1 adipocytes and high-fat diet-induced obese mice. The treatment of EJ, NN, and MIX in 3T3-L1 adipocytes effectively inhibited lipid accumulation, significantly decreased expression of peroxisome proliferator-activated receptor gamma (PPARγ), sterol regulatory element binding protein (SREBP1c), and adipocyte lipid-binding protein (aP2), and significantly increased phosphorylation of AMP-activated protein kinase (AMPK). Moreover, oral treatment of MIX showed stronger effects than individual treatment. C57BL/6J mice (6 week old) were divided into two groups; low fat diet (LFD) containing 10% calories from fat and high fat diet (HFD) containing 60% calories from fat. The HFD groups were further divided into five subgroups; treated with distilled water (HFD), treated with 400 mg/kg EJ (EJ400), treated with 400 mg/kg NN (NN400), treated with 200 mg/kg MIX (MIX200), and treated with 400 mg/kg MIX (MIX400) during 13 weeks. In our results, the administration of EJ, NN, and MIX significantly decreased body weight (BW), fat weight, liver weight, hepatic triglyceride (TG) and total cholesterol (TC), lipid droplets in the liver, food efficacy ratio, and the plasma TG, TC, glucose, insulin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in a dose-dependent manner, and MIX treatment showed stronger effect than their individual treatments. Similarly, MIX treatment decreased the expression of PPARγ, SREBP-1c, FAS, and ACC more strongly in the adipose tissue than single treatments. In conclusion, the MIX of EJ and NN extract may strongly regulate BW gain than EJ or NN alone, and its anti-obesity effect is associated with the control of lipid metabolism, including adipogenesis and lipogenesis.

Obesity, insulin resistance and comorbidities? Mechanisms of association

Overall excess of fat, usually defined by the body mass index, is associated with metabolic (e.g. glucose intolerance, type 2 diabetes mellitus (T2DM), dyslipidemia) and non-metabolic disorders (e.g. neoplasias, polycystic ovary syndrome, non-alcoholic fat liver disease, glomerulopathy, bone fragility etc.). However, more than its total amount, the distribution of adipose tissue throughout the body is a better predictor of the risk to the development of those disorders. Fat accumulation in the abdominal area and in non-adipose tissue (ectopic fat), for example, is associated with increased risk to develop metabolic and non-metabolic derangements. On the other hand, observations suggest that individuals who present peripheral adiposity, characterized by large hip and thigh circumferences, have better glucose tolerance, reduced incidence of T2DM and of metabolic syndrome. Insulin resistance (IR) is one of the main culprits in the association between obesity, particularly visceral, and metabolic as well as non-metabolic diseases. In this review we will highlight the current pathophysiological and molecular mechanisms possibly involved in the link between increased VAT, ectopic fat, IR and comorbidities. We will also provide some insights in the identification of these abnormalities.

Diosgenin, 4-hydroxyisoleucine, and fiber from fenugreek: mechanisms of actions and potential effects on metabolic syndrome

Metabolic syndrome and its complications continue to rise in prevalence and show no signs of abating in the immediate future. Therefore, the search for effective treatments is a high priority in biomedical research. Products derived from botanicals have a time-honored history of use in the treatment of metabolic diseases including type 2 diabetes. Trigonella foenum-graecum, commonly known as fenugreek, is an annual herbaceous plant that has been a staple of traditional herbal medicine in many cultures. Although fenugreek has been studied in both clinical and basic research settings, questions remain about its efficacy and biologic mechanisms of action. Diosgenin, 4-hydroxyisoleucine, and the fiber component of the plant are the most intensively studied bioactive constituents present in fenugreek. These compounds have been demonstrated to exert beneficial effects on several physiologic markers including glucose tolerance, inflammation, insulin action, liver function, blood lipids, and cardiovascular health. Although insights into the molecular mechanisms underlying the favorable effects of fenugreek have been gained, we still do not have definitive evidence establishing its role as a therapeutic agent in metabolic disease. This review aims to summarize the currently available evidence on the physiologic effects of the 3 best-characterized bioactive compounds of fenugreek, with particular emphasis on biologic mechanisms of action relevant in the context of metabolic syndrome.

Hyperglycemia in rodent models of type 2 diabetes requires insulin-resistant alpha cells

To determine the role of glucagon action in diet-induced and genetic type 2 diabetes (T2D), we studied high-fat-diet-induced obese (DIO) and leptin receptor-defective (LepR(-/-)) rodents with and without glucagon receptors (GcgRs). DIO and LepR(-/-),GcgR(+/+) mice both developed hyperinsulinemia, increased liver sterol response element binding protein 1c, and obesity. DIO GcgR(+/+) mice developed mild T2D, whereas LepR(-/-),GcgR(+/+) mice developed severe T2D. High-fat-fed (HFF) glucagon receptor-null mice did not develop hyperinsulinemia, increased liver sterol response element binding protein 1c mRNA, or obesity. Insulin treatment of HFF GcgR(-/-) to simulate HFF-induced hyperinsulinemia caused obesity and mild T2D. LepR(-/-),GcgR(-/-) did not develop hyperinsulinemia or hyperglycemia. Adenoviral delivery of GcgR to GcgR(-/-),LepR(-/-) mice caused the severe hyperinsulinemia and hyperglycemia of LepR(-/-) mice to appear. Spontaneous disappearance of the GcgR transgene abolished the hyperinsulinemia and hyperglycemia. In conclusion, T2D hyperglycemia requires unsuppressible hyperglucagonemia from insulin-resistant α cells and is prevented by glucagon suppression or blockade.

Waist circumference as a vital sign in cardiology 20 years after its initial publication in the American Journal of Cardiology

In 1994, we reported in The American Journal of Cardiology that a simple anthropometric measurement, waist circumference, was related to the amount of abdominal visceral adipose tissue measured by computed tomography. An elevated waist circumference was also found to be associated with several features of the cardiometabolic risk profile such as glucose intolerance, hyperinsulinemia, and an atherogenic dyslipidemic profile that included hypertriglyceridemia and reduced high-density lipoprotein cholesterol levels. Although a linear relation was found between waist circumference and these metabolic alterations, we reported that a waist circumference value of about 100 cm was associated with a high probability of finding diabetogenic and atherogenic abnormalities. The present short report provides a brief update of issues that have been raised regarding the measurement of waist circumference and its clinical use over a period of 20 years since the original publication.

Motor Activity in Aging: An Integrated Approach for Better Quality of Life

Old age is normally associated with stereotypical structural and physiological changes in the brain that are caused by deterioration in elementary cognitive, sensory, and sensorimotor functions as well as increased susceptibility to stress. These changes are connected with gait impairment and falls, especially among patients with common neurological diseases. Even in the absence of history of falling or when there is no physical injury after a fall, many older people develop a fear of falling that leads to restricted mobility, reduced activity, depression, social isolation, worsened metabolic disease, and increasing risk of cardiovascular morbidity and mortality. Although links between cognitive decline and age-associated brain changes have been clarified, relationships between gait disorders and psychophysiological alterations in aging are less well understood. This review focuses on two crucial elements of aged individuals with gait disorders: characteristic comorbidities in the elderly and the psychophysiological effects of physical exercise in the elderly with gait disorder. We propose an integrated approach to studying elderly subjects with gait disorder before starting a program of motor rehabilitation with wearable robotic devices, in order to investigate the effectiveness and safety of the ambulatory training.