Role of subcutaneous adipose tissue in the pathogenesis of insulin resistance

Development and analysis of scaffold-free adipose spheroids

Adipose tissue plays a crucial role in metabolic syndrome, autoimmune diseases, and many cancers. Because of adipose's role in so many aspects of human health, there is a critical need for in vitro models that replicate adipose architecture and function. Traditional monolayer models, despite their convenience, are limited, showing heterogeneity and functional differences compared to 3D models. While monolayer cultures struggle with detachment and inefficient differentiation, healthy adipocytes in 3D culture accumulate large lipid droplets, secrete adiponectin, and produce low levels of inflammatory cytokines. The shift from monolayer models to more complex 3D models aims to better replicate the physiology of healthy adipose tissue in culture. This study introduces a simple and accessible protocol for generating adipose organoids using a scaffold-free spheroid model. The method, utilizing either 96-well spheroid plates or agarose micromolds, demonstrates increased throughput, uniformity, and ease of handling compared to previous techniques. This protocol allows for diverse applications, including drug testing, toxin screening, tissue engineering, and co-culturing. The choice between the two methods depends on the experimental goals, with the 96-well plate providing individualized control and the micromold offering scale advantages. The outlined protocol covers isolation, expansion, and characterization of stromal vascular fraction cells, followed by detailed steps for spheroid formation and optional downstream analyses.

Plasma adiponectin/leptin ratio associates with subcutaneous abdominal and omental adipose tissue characteristics in women

BACKGROUND

A better understanding of adipose tissue (AT) dysfunction, which includes morphological and functional changes such as adipocyte hypertrophy as well as impaired adipogenesis, lipid storage/mobilization, endocrine and inflammatory responses, is needed in the context of obesity. One dimension of AT dysfunction, secretory adiposopathy, often assessed as a low plasma adiponectin (A)/leptin (L) ratio, is commonly observed in obesity. The aim of this study was to examine markers of AT development and metabolism in 67 women of varying age and adiposity (age: 40-62 years; body mass index, BMI: 17-41 kg/m2) according to levels of adiponectinemia, leptinemia or the plasma A/L ratio.

METHODS

Body composition, regional AT distribution and circulating adipokines were determined. Lipolysis was measured from glycerol release in subcutaneous abdominal (SCABD) and omental (OME) adipocytes under basal, isoproterenol-, forskolin (FSK)- and dibutyryl-cyclic AMP (DcAMP)-stimulated conditions. Adipogenesis (C/EBP-α/β/δ, PPAR-γ2 and SREBP-1c) and lipid metabolism (β2-ARs, HSL, FABP4, LPL and GLUT4) gene expression (RT-qPCR) was assessed in both fat depots. Participants in the upper versus lower tertile of adiponectin, leptin or the A/L ratio were compared.

RESULTS

Basal lipolysis was similar between groups. Women with a low plasma A/L ratio were characterized by higher adiposity and larger SCABD and OME adipocytes (p<0.01) compared to those with a high ratio. In OME adipocytes, women in the low adiponectinemia tertile showed higher isoproterenol-stimulated lipolysis (0.01

CONCLUSIONS

Secretory adiposopathy assessed as the plasma A/L ratio, more so than adiponectin or leptin levels alone, discriminates low and elevated lipolysis in OME and SCABD adipocytes despite similar AT expression of selected genes involved in lipid metabolism.

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Key Words

• Adipogenesis
• Adipokines
• Adipose cell lipolysis
• Adipose tissue gene expression
• Lipid metabolism

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MESH Headings

• Female
• Humans
• Adult
• Middle Aged
• Adiponectin/metabolism
• Leptin/metabolism
• Isoproterenol/metabolism
• Adipose Tissue/metabolism
• Obesity/metabolism

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Grants

• MOP-64182 and MOP-102642 CIHR
• Canadian Institutes of Health Research
• Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec

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Affiliation(s)

Eve-Julie Tremblay École de Nutrition, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec City, Canada Centre de recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec (CRIUCPQ), Université Laval, Québec City, Canada
André Tchernof École de Nutrition, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec City, Canada Centre de recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec (CRIUCPQ), Université Laval, Québec City, Canada
Mélissa Pelletier Centre de recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec (CRIUCPQ), Université Laval, Québec City, Canada
Denis R Joanisse Centre de recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec (CRIUCPQ), Université Laval, Québec City, Canada Département de kinésiologie, Faculté de médecine, Université Laval, Québec City, Canada
Pascale Mauriège Centre de recherche de l'Institut Universitaire de Cardiologie et Pneumologie de Québec (CRIUCPQ), Université Laval, Québec City, Canada. Département de kinésiologie, Faculté de médecine, Université Laval, Québec City, Canada.

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Novel Anthropometric Indices as Screening Tools for Obesity: A Study on Healthy Iranians

Background and Aims

Upper body fat distribution is more related to cardiometabolic diseases than central obesity. Neck circumference (NC) and neck-to-height ratio (NHtR) are two indicators of upper body obesity that are affordable, easy to obtain, highly reproducible, and more practical in the crowded health centers than the classic anthropometric indices.

Methods

18-65-year-old individuals with no past medical history were included. After obtaining written informed consent, they were screened for hypertension, high blood glucose, and other abnormal laboratory results. Data were analyzed using SPSS and Mann-Whitney U test, Chi square test, Spearman's correlation coefficient, and ROC curve.

Results

In our 2,812 participants, NC had the lowest area under the curve (AUC) in both male and female obese and overweight subjects. NHtR and hip circumference (HC) had the highest AUC in men and women with obesity, respectively. The highest sensitivity for overweight men and women belonged to waist circumference (WC) and waist-to-height ratio (WHtR), respectively, and for both males and females with obesity, NHtR had the highest sensitivity. The cutoff point of NHtR had the same value for males and females. HC and NHtR had the highest positive likelihood ratio (PLR) for obesity in men. In addition, HC and WC had the highest PLR for obesity in women.

Conclusion

In this study, we revealed that NC had the lowest and NHtR and HC had the highest predictive value for obesity. Furthermore, for both males and females with obesity, NHtR had the highest sensitivity. HC had the highest PLR for obesity in both genders. Our results warrant prospective studies to evaluate the role of NHtR and other novel anthropometric indices in the risk of cardiometabolic diseases.

Sarcopenia negatively affects postoperative short-term outcomes of patients with non-cirrhosis liver cancer

BACKGROUND

Literature review have shown that sarcopenia substantially alters the postoperative outcomes after liver resection for malignant tumors. However, these retrospective studies do not distinguish cirrhotic and non-cirrhotic liver cancer patients, nor combine the assessment of muscle strength in addition to muscle mass. The purpose of this study is to study the relationship between sarcopenia and short-term outcomes after hepatectomy in patients with non-cirrhotic liver cancer.

METHODS

From December 2020 to October 2021, 431 consecutive inpatients were prospectively enrolled in this study. Muscle strength and mass were assessed by handgrip strength and the skeletal muscle index (SMI) on preoperative computed tomographic scans, respectively. Based on the SMI and the handgrip strength, patients were divided into four groups: group A (low muscle mass and strength), group B (low muscle mass and normal muscle strength), group C (low muscle strength and normal muscle mass), and group D (normal muscle mass and strength). The main outcome was major complications and the secondary outcome was 90-d Readmission rate.

RESULTS

After strictly exclusion, 171 non-cirrhosis patients (median age, 59.00 [IQR, 50.00-67.00] years; 72 females [42.1%]) were selected in the final analysis. Patients in group A had a statistically significantly higher incidence of major postoperative complications (Clavien-Dindo classification ≥ III) (26.1%, p = 0.032), blood transfusion rate (65.2%, p < 0.001), 90-day readmission rate (21.7%, p = 0.037) and hospitalization expenses (60,842.00 [IQR, 35,563.10-87,575.30], p < 0.001) than other groups. Sarcopenia (hazard ratio, 4.21; 95% CI, 1.44-9.48; p = 0.025) and open approach (hazard ratio, 2.56; 95% CI, 1.01-6.49; p = 0.004) were independent risk factors associated with major postoperative complications.

CONCLUSIONS

Sarcopenia is closely related to poor short-term postoperative outcomes in non-cirrhosis liver cancer patients and the assessment that combines muscle strength and muscle mass can simply and comprehensively identify it.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers NCT04637048 . (19/11/2020).

Gene expression profiling of subcutaneous adipose tissue reveals new biomarkers in acromegaly

CONTEXT

Active acromegaly is characterized by lipolysis-induced insulin resistance, which suggests adipose tissue (AT) as a primary driver of metabolic aberrations.

OBJECTIVE

To study the gene expression landscape in AT in patients with acromegaly before and after disease control in order to understand the changes and to identify disease-specific biomarkers.

METHODS

RNA sequencing was performed on paired subcutaneous adipose tissue (SAT) biopsies from six patients with acromegaly at time of diagnosis and after curative surgery. Clustering and pathway analyses were performed in order to identify disease activity-dependent genes. In a larger patient cohort (n = 23), the corresponding proteins were measured in serum by immunoassay. Correlations between growth hormone (GH), insulin-like growth factor I (IGF-I), visceral AT (VAT), SAT, total AT, and serum proteins were analyzed.

RESULTS

743 genes were significantly differentially expressed (P-adjusted < .05) in SAT before and after disease control. The patients clustered according to disease activity. Pathways related to inflammation, cell adhesion and extracellular matrix, GH and insulin signaling, and fatty acid oxidation were differentially expressed.Serum levels of HTRA1, METRNL, S100A8/A9, and PDGFD significantly increased after disease control (P < .05). VAT correlated with HTRA1 (R = 0.73) and S100A8/A9 (R = 0.55) (P < .05 for both).

CONCLUSION

AT in active acromegaly is associated with a gene expression profile of fibrosis and inflammation, which may corroborate the hyper-metabolic state and provide a means for identifying novel biomarkers.

The Link between NAFLD and Metabolic Syndrome

Metabolic syndrome (MetS) is characterized by an association of cardiovascular and diabetes mellitus type 2 risk factors. Although the definition of MetS slightly differs depending on the society that described it, its central diagnostic criteria include impaired fasting glucose, low HDL-cholesterol, elevated triglycerides levels and high blood pressure. Insulin resistance (IR) is believed to be the main cause of MetS and is connected to the level of visceral or intra-abdominal adipose tissue, which could be assessed either by calculating body mass index or by measuring waist circumference. Most recent studies revealed that IR may also be present in non-obese patients, and considered visceral adiposity to be the main effector of MetS' pathology. Visceral adiposity is strongly linked with hepatic fatty infiltration also known as non-alcoholic fatty liver disease (NAFLD), therefore, the level of fatty acids in the hepatic parenchyma is indirectly linked with MetS, being both a cause and a consequence of this syndrome. Taking into consideration the present pandemic of obesity and its tendency to drift towards a progressively earlier onset due to the Western lifestyle, it leads to an increased NAFLD incidence. Novel therapeutic resources are lifestyle intervention with physical activity, Mediterranean diet, or therapeutic surgical respective metabolic and bariatric surgery or drugs such as SGLT-2i, GLP-1 Ra or vitamin E. NAFLD early diagnosis is important due to its easily available diagnostic tools such as non-invasive tools: clinical and laboratory variables (serum biomarkers): AST to platelet ratio index, fibrosis-4, NAFLD Fibrosis Score, BARD Score, fibro test, enhanced liver fibrosis; imaging-based biomarkers: Controlled attenuation parameter, magnetic resonance imaging proton-density fat fraction, transient elastography (TE) or vibration controlled TE, acoustic radiation force impulse imaging, shear wave elastography, magnetic resonance elastography; and the possibility to prevent its complications, respectively, fibrosis, hepato-cellular carcinoma or liver cirrhosis which can develop into end-stage liver disease.

Polysaccharide-rich fractions from Enteromorpha prolifera improve hepatic steatosis and gut barrier integrity in high-fat diet-induced obese mice linking to modulation of gut microbiota

Polysaccharides from Enteromorpha prolifera (EP) possess important benefits in the management of obesity and associated metabolic diseases, but to date, the underlying mechanism linking this alleviative effect of EP to gut microbiota remains obscure. This study aimed to investigate the effects of EP in improving lipid metabolism disorders and intestinal barrier disruption in mice with high-fat diet (HFD), and its association with modulation of gut microbiota. C57BL/6 mice were fed a control diet or a HFD with or without 5% EP for 12 weeks. Factors related to lipid metabolism, insulin signaling and intestinal barrier integrity, as well as the involvement of gut microbiota and metabolites, were measured. EP supplementation reduced HFD-induced adiposity and mitigated insulin resistance, hepatic steatosis and elevation of serum lipopolysaccharides (LPS). HFD impaired intestinal barrier integrity while improved due to EP. Moreover, EP administration ameliorated HFD-induced gut dysbiosis, as revealed by the increased short-chain fatty acid (SCFA)-producing bacteria (e.g., Bacteroides, Parabacteroides, Alloprevotella, and Ruminococcus) and gut barrier-protective Akkermansia muciniphila and decreased endotoxin-producing bacteria (e.g., Desulfovibrionaceae and Bilophila), accompanied by enrichment in intestinal SCFA content and reduction in circulating LPS level. The change of dominant bacterial genera is significantly correlated with improved metabolic profiles and intestinal permeability induced by EP. In conclusion, our results indicate that EP can attenuate HFD-induced metabolic disorders along with restoration of gut barrier integrity and lowering of circulating endotoxin, and these improvements are associated with modulation of gut microbiota composition and related metabolites. These data deepen mechanistic understanding of the anti-obesity and metabolic improving effects of EP.

Utility of high-resolution ultrasound in measuring subcutaneous fat thickness

OBJECTIVE

Previous studies conclude that high-resolution ultrasound (HRUS) enables noninvasive and accurate measurements of subcutaneous fat thickness. The primary objective of this cross-sectional study was to better characterize subcutaneous fat thickness measurements in a diverse patient population using HRUS. Secondarily, we sought to correlate these measurements with patients' body image.

METHODS

A cross-sectional study to measure subcutaneous fat measurements at seven distinct anatomic sites, including upper and lower extremities, submental, and torso regions, in 40 men and women of different ages and races using HRUS. Independent t-tests and analysis of variance were performed to analyze findings.

RESULTS

In our patient population, on average, women had thicker subcutaneous fat than men at all anatomic sites. Asian patients had significantly reduced fat thickness at peripheral anatomic sites, such as arms when compared to patients who identified as Black and Other (p = 0.05 and p = 0.008, respectively). Lastly, women reported decreased total body satisfaction at all anatomic sites when compared to men.

CONCLUSION

The information obtained and methods developed in this study may be utilized clinically during patient selection for fat reduction procedures, including for estimating the degree of likely benefit; for managing pathologies involving subcutaneous fat thickness alteration; and to monitor the progression of lipodystrophy secondary to disease or drugs.

Untapped Pharmaceutical Potential of 4,5,4'-Trihydroxy-3,3'-dimethoxybibenzyl for Regulating Obesity: A Cell-Based Study with a Focus on Terminal Differentiation in Adipogenesis

Obesity and its global prevalence has become a threat to human health, while its pharmacotherapy via the application of natural products is still underdeveloped. Here, we probed how 4,5,4'-trihydroxy-3,3'-dimethoxybibenzyl (TDB) derived from an orchid (Dendrobium ellipsophyllum) could exert its roles on the differentiation and function of murine (3T3-L1) and human (PCS-210-010) pre-adipocytes and offer some implications to modulate obesity. Cytotoxic effects of TDB on adipocytes were 2-fold lower than those detected with pre-adipocytes, and no significant difference was detected in cytotoxic profiles between both cell lineages. TDB in a dose-dependent manner decreased cellular lipid accumulation and enhanced lipolysis of both cell lines assessed at early differentiation and during maturation. Underlining molecular mechanisms proved that TBD paused the cell cycle progression by regulating inducers and inhibitors in mitotic clonal expansion, leading to growth arrest of pre-adipocytes at the G0/G1 phase. The compound also governed adipocyte differentiation by repressing expressions of crucial adipogenic regulators and effectors through deactivating the AKT/GSK-3β signaling pathway and activating the AMPK-ACC pathway. To this end, TDB has shown its pharmaceutical potential for modulating adipocyte development and function, and it would be a promising candidate for further assessments as a therapeutic agent to defeat obesity.

Do patients with Prader-Willi syndrome have favorable glucose metabolism?

Background

In recent years, more studies have observed that patients with Prader–Willi syndrome have lower insulin levels and lower insulin resistance than body mass index-matched controls, which may suggest protected glucose metabolism.

Method

The PubMed and Web of Science online databases were searched to identify relevant studies published in the English language using the terms “Prader–Willi syndrome” with “glucose”, “insulin”, “diabetes mellitus”, “fat”, “adipo*”, “ghrelin”, “oxytocin”, “irisin” or “autonomic nervous system”.

Results

The prevalence of impaired glucose intolerance, type 2 diabetes mellitus and some other obesity-associated complications in patients with Prader–Willi syndrome tends to be lower when compared to that in general obesity, which is consistent with the hypothetically protected glucose metabolism. Factors including adipose tissue, adiponectin, ghrelin, oxytocin, irisin, growth hormone and the autonomic nervous system possibly modulate insulin sensitivity in patients with Prader–Willi syndrome.

Conclusion

Although lower insulin levels, lower IR and protected glucose metabolism are widely reported in PWS patients, the causes are still mysterious. Based on existing knowledge, we cannot determine which factor is of utmost importance and what are the underlying mechanisms, and further research is in urgent need.

Sex differences in regional adipose tissue depots pose different threats for the development of Type 2 diabetes in males and females

Type 2 diabetes mellitus (T2DM) affects males and females disproportionately. In midlife, more males have T2DM than females. The sex difference in T2DM prevalence is, in part, explained by differences in regional adipose tissue characteristics. With obesity, changes to regional adipokine and cytokine release increases the risk of T2DM in both males and females with males having greater levels of TNFα and females having greater levels of leptin, CRP, and adiponectin. Regional immune cell infiltration appears to be pathogenic in both sexes via different routes as males with obesity have greater VAT ATM and a decrease in the protective Treg cells, whereas females have greater SAT ATM and T cells. Lastly, the ability of female adipose tissue to expand all regions through hyperplasia, rather than hypertrophy, protects them against the development of large insulin-resistant adipocytes that dominate male adipose tissue. The objective of this review is to discuss how sex may affect regional differences in adipose tissue characteristics and how these differences may distinguish the development of T2DM in males and females. In doing so, we will show that the origins of T2DM development differ between males and females.

Neck circumference as a screening measure for identifying NAFLD among a group of academic employees in Bangkok, Thailand

Neck circumference (NC) reflects the fat deposition in upper body and has potential to be used as a predictor of Non-Alcoholic Fatty Liver Disease (NAFLD). Our objectives were to examine the association of NC with NAFLD prevalence, and to determine the optimal cut-off of NC in identifying the presence of NAFLD among the employees of an academic institution in Bangkok, Thailand. In this cross-sectional study, 635 employees of an academic institution underwent anthropometric measurement and transient elastography following an overnight fast. NAFLD was defined as a CAP value >238 dB.m-1. The NAFLD prevalence in men and women were 66.17% and 46.22%, respectively. The mean NCs for men and women with NAFLD were higher (38.53±0.31 cm and 35.83±0.48 cm, respectively) than those without NAFLD (33.58±0.24 and 31.098±0.14 cm, respectively) (p<0.001). Metabolic markers including age, weight, BMI, NC, WC, WHR, FBS, triglycerides were significantly higher, HDL was significantly lower among participants with NAFLD compared to those without NAFLD (p<0.05). NC was independently associated with NAFLD among women with OR (95%CI) of 1.17 (1.05, 1.32). The optimal cut-offs of NC to predict NAFLD were 37.07 cm (sensitivity: 70.50%; specificity: 68.90%) and 32.07 cm (sensitivity: 70.70%; specificity: 62.10%), respectively for men and women. NC significantly correlated with NAFLD in women. The optimal cut-off points of 32 cm and 37 cm for men and women, which similar to Chinese populations. Therefore, it can be used as a cost-effective tool to predict NAFLD.

Trial Registration: Thai Clinical Trials Registry (TCTR20210329006)

Quercetin improves the adipose inflammatory response and insulin signaling to reduce "real-world" particulate matter-induced insulin resistance

Numerous epidemiological data and experimental studies support a strong link between fine particulate matter (less than 2.5 mm in aerodynamic diameter, PM_2.5) exposure and the development of insulin resistance/type 2 diabetes mellitus (T2DM). Quercetin (Que), a flavonoid compound with anti-inflammatory effects, has been confirmed to improve glucose metabolic disorders in rodents and humans. In this study, we investigated the underlying mechanisms of particulate matter (PM)-induced glucose metabolic disorder and subsequently examined the protective effect and mechanism of quercetin supplementation. Male C57BL/6 mice in the control group and PM group were exposed to ambient filtered air (FA) or PM (6 h/day, 7 days/week) for 18 weeks. Mice in the Que group were exposed to PM for 18 weeks and administered Que (50 or 100 mg/kg bw). Glucose tolerance, insulin sensitivity, and systemic and visceral white adipose tissue (vWAT) inflammatory responses were measured. The expression of proteins involved in insulin signal transduction in vWAT was assessed. Chronic PM exposure caused systemic and vWAT inflammation characterized by an increase in serum IL-6 and TNF-α levels and increased vWAT macrophage filtration, triggering NLRP3 inflammasome activation, impairing the classic glucose metabolism signal in vWAT, and inducing whole-body insulin resistance. Moreover, Que administration significantly alleviated systemic and vWAT inflammation, abolished NLRP3 inflammasome activation, and improved signaling abnormalities characteristic of insulin resistance in vWAT and adipocytes. Based on these findings, chronic PM exposure activated the NLRP3 inflammasome and subsequently caused systemic and WAT inflammation and impaired insulin signaling in vWAT and adipocytes. Most importantly, Que administration inhibited NLRP3 inflammasome-mediated inflammation and insulin signaling in vWAT to improve these adverse effects.

Physical activity in the management of obesity in adults: A position statement from Exercise and Sport Science Australia

This Position Statement examines the evidence for physical activity in weight and adiposity loss, prevention of weight and adiposity gain, and in weight regain in adults, and provides guidance on implications for exercise practitioners. Research evidence indicates that >150 min but preferably 300 min per week of aerobic activity of at least moderate intensity is required to prevent weight and adiposity gain, and at least the upper end of this range of activity to prevent weight regain after weight loss. For meaningful weight and total adiposity loss, a minimum of 300-420 min per week of aerobic activity of at least moderate intensity is required. The evidence around the volume of aerobic physical activity required to reduce central adiposity is emerging, and research suggests that it may be substantially less than that required for weight loss. The impact of high-intensity physical activity and resistance exercise for weight management is uncertain. During consultations for weight management, exercise practitioners should advise that metabolic and cardiovascular health benefits can be achieved with physical activity at any weight, and irrespective of weight change.

An association between subcutaneous fat mass accumulation and hypertension

Evidence to assess relationships between subcutaneous fat area (SFA) and lifestyle-related diseases, including hypertension, remains limited. The aim of this study was to investigate the relationship between SFA and hypertension. This study was a single-institution, cross-sectional study of 1,899 eligible Japanese participants who underwent health checkups between December 2016 and December 2018. All patients were measured for SFA and visceral fat area (VFA) by abdominal computed tomography (CT). SFA was divided into quartiles by gender, and multivariate logistic regression analysis was performed to estimate associations between SFA quartiles (Q) and hypertension. Mean age and SFA were 60.9 9 (standard devastation [SD]:12.0) years and 123.0 (56.9) cm2 in men, and 60.6 (12.8) years and 146.6 (79.0) cm2 in women, respectively. Risk of hypertension from multivariate regression modeling compared with the lowest quartile (Q) in both sexes was as follows: for men Q2 [odds ratio (OR), 1; 95% confidence interval (CI), 0.55-1.51 ], Q3 (OR, 1.73; 95%CI, 1.17-2.56), and Q4 (OR, 1.96; 95%CI, 1.31-2.94); for women Q2 (OR, 0.87; 95%CI, 0.48-1.58), Q3 (OR, 1.73; 95%CI, 1.02-2.95), and Q4 (OR, 2.54; 95%CI, 1.51-4.28). The optimal SFA cutoff value at risk of hypertension was 114.7 cm2 in men and 169.3 cm2 in women. The prevalence of hypertension was positively associated with SFA quartiles in both genders. The present results may indicate the necessity of considering not only VFA, but also SFA for the primary and secondary prevention of hypertension.

Age-associated telomere attrition in adipocyte progenitors predisposes to metabolic disease

White and beige adipocytes in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) are maintained by proliferation and differentiation of adipose progenitor cells (APCs). Here we use mice with tissue-specific telomerase reverse transcriptase (TERT) gene knockout (KO), which undergo premature telomere shortening and proliferative senescence in APCs, to investigate the effect of over-nutrition on APC exhaustion and metabolic dysfunction. We find that TERT KO in the Pdgfra⁺ cell lineage results in adipocyte hypertrophy, inflammation and fibrosis in SAT, while TERT KO in the Pdgfrb⁺ lineage leads to adipocyte hypertrophy in both SAT and VAT. Systemic insulin resistance is observed in both KO models and is aggravated by a high-fat diet. Analysis of human biopsies demonstrates that telomere shortening in SAT is associated with metabolic disease progression after bariatric surgery. Our data indicate that over-nutrition can promote APC senescence and provide a mechanistic link between ageing, obesity and diabetes.

The Fat-to-Lean Mass Ratio Is Associated with Hyperinsulinemia in Healthy Mexican Adolescents

Objective: To evaluate whether the Fat-to-Lean Mass (FyM) ratio is associated to hyperinsulinemia in healthy adolescents.Methods: Apparently healthy adolescents aged 10 to 15 years that according to sex, age, and percentiles of body fat percent, were included and allocated into the groups with elevated (body fat percent ≥85 percentile) and normal total body fat (body fat percent <85 percentile). The FyM ratio was calculated as total lean mass (kg)/total body fat (kg) and hyperinsulinemia was defined by fasting insulin levels ≥20 µUI/mL.Results: A total of 1,299 adolescents, 665 (51.9%) girls and 634 (48.1%) boys, were enrolled and allocated into the groups with high (n = 439) and normal (n = 860) body fat. The FyM index remained significantly associated with hyperinsulinemia (OR 5.58; _95%CI: 1.54-28.10) after logistic regression analysis adjusted by sex, age, body-weight, body mass index, and waist circumference.Conclusion: The FyM index is highly associated to the presence of hyperinsulinemia in adolescents, emerging as a useful tool from anthropometric measurements for identify insulin abnormalities.

Glycaemia and hand grip strength in aging people: Guangzhou biobank cohort study

BACKGROUND

There is a link between hyperglycemia and mechanical functions of muscle. However, existing evidence of the association between hyperglycemia and weaker muscle strength is limited and inconsistent. We examined whether glycemic status was associated with relative grip strength (RGS) in older Chinese.

METHODS

In 2008-2012, 9180 participants (2516 men and 6664 women) from the Guangzhou Biobank Cohort Study had fasting and 2-h post-load glucose measured. Glycemic status was categorized as normoglycaemia, prediabetes (i.e., impaired fasting glucose and/or impaired glucose tolerance) and diabetes. RGS was assessed using a Jamar Hydraulic Hand Dynamometer divided by body mass index. General linear model was used to assess the association of glycemic status with RGS.

RESULTS

After adjusting for age, smoking status, alcohol use, physical activity, health status, body fat percentage and waist circumference, in men, hyperglycemia was associated with a lower RGS, with the RGS being 1.38 (95% confidence interval (CI) = 1.34, 1.42) in normoglycaemia, 1.35 (95% CI = 1.30, 1.39) in prediabetes, 1.33 (95% CI = 1.29, 1.38) in newly diagnosed diabetes and 1.32 (95% CI = 1.27, 1.37) in known diabetes (P for trend < 0.001). The association of glycemic status with RGS was non-significant in women. Among the normoglycaemic group, no association was found between fasting glucose and RGS in men, whereas a significantly inverse association was found in women, with adjusted β for RGS per mmol/l increase in fasting glucose being - 0.05 to - 0.04 (P values from 0.002 to 0.03).

CONCLUSIONS

Higher fasting glucose was associated with reduced grip strength in a dose-response manner, and the association was significant even in women with normoglycaemia. Our findings suggest that lowering glucose across the whole range might be important in preserving muscle strength, especially in aging women.

Comparing an adiposopathy approach with four popular classifications schemes to categorize the metabolic profile of postmenopausal women

Numerous classifications are used to discern metabolically healthy obese (MHO) from metabolically abnormal obese (MAO) individuals. The goal of this study was to compare a single phenotype approach, adiposopathy (i.e., the plasma adiponectin/leptin ratio), with four commonly used classifications (International Diabetes Federation (IDF), Karelis, Lynch, Wildman), all based on obesity with other risk factors), for their ability to discern phenotypic differences between MAO and MHO postmenopausal women. Anthropometry, body composition, blood pressure, cardiorespiratory fitness (CRF), lipid-lipoprotein, hepatic, inflammatory, and adipokine profiles, as well as glucose-insulin homeostasis, were assessed in 79 obese sedentary postmenopausal women (60 ± 5 years; body mass index, BMI, 34.0 ± 3.7 kg/m²). Abdominal subcutaneous adipose tissue (SCAT) expression of selected genes involved in fatty acid metabolism and inflammation was used as markers of tissue state (n = 48). Beyond their intrinsic criteria, adiposopathy was almost as effective as the Karelis definition in discerning differences in MHO for adiposity (reduced body weight, BMI, waist circumference, and fat mass), lipid-lipoprotein (lower triacylglycerol and higher HDL-cholesterol levels, reduced atherogenic ratios) and adipokine (higher adiponectin and lower leptin levels) profiles, and glucose-insulin homeostasis (lower insulin resistance) as well as for some SCAT gene expression related to lipolysis and lipogenesis, but was the only one able to distinguish these subjects for greater CRF. The other classifications revealed fewer differences between MAO and MHO women. These data suggest that considering a marker of AT dysfunction such as adiposopathy either alone or in addition to other criteria could be potentially interesting in discerning the MHO phenotype.

Imaging of body composition in children

Overweight and obesity in children and adolescents have become a worldwide public health concern with an ever-increasing prevalence. An excessive accumulation of intraabdominal fat tissue increases the risk of developing insulin resistance, diabetes, and cardiovascular diseases in adulthood. Body composition has a role in metabolism regulation in children and adolescents with differences between genders and age groups. Until recently, Air Displacement Plethysmography and Dual-energy X-ray Absorptiometry (DXA) have been the most common techniques used to assess body composition in children. Ultrasound (US) is an accurate, readily available, and radiation-free technique to quantify intra-abdominal fat in adults, but its use in children has not yet been validated. Computed tomography (CT) is a reliable tool to assess body composition, but its use in children should be avoided due to the significant radiation burden. Quantitative Magnetic Resonance Imaging (qMRI) provides an accurate measurement of body composition, through the quantification of the visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and brown adipose tissue (BAT), as well as lean mass. Furthermore, qMRI provides other significant estimates such as the Proton Density Fat-Fraction of the fat tissue. This review article aims to briefly describe the state of art of the advanced imaging techniques to provide a quantitative assessment of body composition in children and adolescents.

Pdgfrα-Cre mediated knockout of the aryl hydrocarbon receptor protects mice from high-fat diet induced obesity and hepatic steatosis

Aryl hydrocarbon receptor (AHR) agonists such as dioxin have been associated with obesity and the development of diabetes. Whole-body Ahr knockout mice on high-fat diet (HFD) have been shown to resist obesity and hepatic steatosis. Tissue-specific knockout of Ahr in mature adipocytes via adiponectin-Cre exacerbates obesity while knockout in liver increases steatosis without having significant effects on obesity. Our previous studies demonstrated that treatment of subcutaneous preadipocytes with exogenous or endogenous AHR agonists disrupts maturation into functional adipocytes in vitro. Here, we used platelet-derived growth factor receptor alpha (Pdgfrα)-Cre mice, a Cre model previously established to knock out genes in preadipocyte lineages and other cell types, but not liver cells, to further define AHR's role in obesity. We demonstrate that Pdgfrα-Cre Ahr-floxed (Ahrfl/fl) knockout mice are protected from HFD-induced obesity compared to non-knockout Ahrfl/fl mice (control mice). The Pdgfrα-Cre Ahrfl/fl knockout mice were also protected from increased adiposity, enlargement of adipocyte size, and liver steatosis while on the HFD compared to control mice. On a regular control diet, knockout and non-knockout mice showed no differences in weight gain, indicating the protective phenotype arises only when animals are challenged by a HFD. At the cellular level, cultured cells from brown adipose tissue (BAT) of Pdgfrα-Cre Ahrfl/fl mice were more responsive than cells from controls to transcriptional activation of the thermogenic uncoupling protein 1 (Ucp1) gene by norepinephrine, suggesting an ability to burn more energy under certain conditions. Collectively, our results show that knockout of Ahr mediated by Pdgfrα-Cre is protective against diet-induced obesity and suggest a mechanism by which enhanced UCP1 activity within BAT might confer these effects.

Fat Distribution in Women Is Associated With Depot-Specific Transcriptomic Signatures and Chromatin Structure

BACKGROUND

Preferential accumulation of fat in the upper body (apple shape) is associated with higher risk of developing metabolic syndrome relative to lower body fat (pear shape). We previously discovered that chromatin openness partially defined the transcriptome of preadipocytes isolated from abdominal and gluteofemoral fat. However, the molecular mechanisms underlying interindividual variation in body shape are unknown.

METHODS

Adipocyte fraction was isolated from abdominal and gluteofemoral fat biopsies of premenopausal women (age and body mass index matched) segregated initially only by their waist-to-hip ratio. We evaluated transcriptomic and chromatin accessibility using RNA sequencing and assay for transposase-accessible chromatin using sequencing (ATAC-seq) along with key clinical parameters.

RESULTS

Our data showed that higher lower body fat mass was associated with better lipid profile and free fatty acid decrease after glucose administration. Lipid and glucose metabolic pathways genes were expressed at higher levels in gluteofemoral adipocyte fraction in pears, whereas genes associated with inflammation were higher both in abdominal and gluteofemoral apple adipocyte fraction. Gluteofemoral adipocyte chromatin from pear-shaped women contained a significantly higher number of differentially open ATAC-seq peaks relative to chromatin from the apple-shaped gluteofemoral adipocytes. In contrast, abdominal adipocyte chromatin openness showed few differences between apple- and pear-shaped women. We revealed a correlation between gene transcription and open chromatin at the proximity of the transcriptional start site of some of the differentially expressed genes.

CONCLUSIONS

Integration of data from all 3 approaches suggests that chromatin openness partially governs the transcriptome of gluteofemoral adipocytes and may be involved in the early metabolic syndrome predisposition associated with body shape.

Physical Health Status of Emergency Care Providers in South Africa

Background: Emergency care providers (ECPs) have a physically, mentally, and emotionally demanding profession. Therefore, they are predisposed to cardiovascular and other non-communicable disease risk factors. Objectives: The objective of the study was to determine the physical health status of ECPs in the North West province of South Africa through a selected anthropometric and other health parameter test battery. Methods: Ninety-one ECPs (64 males, 27 females) took part in the study voluntarily for health screening tests including body mass index (BMI), lean body mass (LBM), resting heart rate (RHR), blood pressure (BP), skinfold measurement, waist circumference (WC), waist-to-hip ratio (WHR), fasting blood glucose (FBG), and total cholesterol (TC). The collected data were subjected to statistical analysis using the Statistical Package for Social Sciences (SPSS) version 25 (IBM). Results: The participants demonstrated a mean BMI of 28.2 ± 5.5 kg/m2, body fat of 26 ± 7.6 %, and LBM of 58.6 ± 10 kg. Significant differences were seen in height (170.5 ± 6.2 vs. 160.7 ± 5.3 cm), BF% (22.5 ± 5.3 vs. 34.2 ± 6.2 %), and LBM (62.3 ± 8 vs. 49.2 ± 8.2 kg) between males and females (P ≤ 0.05). Mean systolic BP was 122 ± 15 mmHg, and diastolic BP was 81 ± 10 mmHg. Mean WC was 90.8 ± 11.4 cm. Other health parameters included mean FBG of 5.1 ± 2.4 mmol/L and mean TC of 4.9 ± 0.7 mmol/L. Significant differences were seen in WHR (0.88 ± 0.04 vs. 0.79 ± 0.06) between males and females (P ≤ 0.05). Conclusions: A significant number of ECPs presented with cardiovascular and other NCD risk factors such as hypertension, obesity, high WC, elevated FBG, and abnormal levels of TC. This can be attributed to the nature of their occupation such as working irregular shifts leading to sleep deprivation, being exposed to psychological trauma, poor nutrition during shifts, and/or lack of exercise. Stress management is an important part of these workers’ rehabilitation program. A well-formulated employee wellness program is required to set remedial measures in place.

Glucose transporter 10 modulates adipogenesis via an ascorbic acid-mediated pathway to protect mice against diet-induced metabolic dysregulation

The development of type 2 diabetes mellitus (T2DM) depends on interactions between genetic and environmental factors, and a better understanding of gene-diet interactions in T2DM will be useful for disease prediction and prevention. Ascorbic acid has been proposed to reduce the risk of T2DM. However, the links between ascorbic acid and metabolic consequences are not fully understood. Here, we report that glucose transporter 10 (GLUT10) maintains intracellular levels of ascorbic acid to promote adipogenesis, white adipose tissue (WAT) development and protect mice from high-fat diet (HFD)-induced metabolic dysregulation. We found genetic polymorphisms in SLC2A10 locus are suggestively associated with a T2DM intermediate phenotype in non-diabetic Han Taiwanese. Additionally, mice carrying an orthologous human Glut10^G128E variant (Glut10^G128E mice) with compromised GLUT10 function have reduced adipogenesis, reduced WAT development and increased susceptibility to HFD-induced metabolic dysregulation. We further demonstrate that GLUT10 is highly expressed in preadipocytes, where it regulates intracellular ascorbic acid levels and adipogenesis. In this context, GLUT10 increases ascorbic acid-dependent DNA demethylation and the expression of key adipogenic genes, Cebpa and Pparg. Together, our data show GLUT10 regulates adipogenesis via ascorbic acid-dependent DNA demethylation to benefit proper WAT development and protect mice against HFD-induced metabolic dysregulation. Our findings suggest that SLC2A10 may be an important HFD-associated susceptibility locus for T2DM.

Environmental triggers may amplify genetically determined disease susceptibility, especially for carriers of rare variants with relatively large individual effect sizes, making these polymorphisms highly informative for predicting individualized clinical risk and preventing disease. Since transitions in dietary pattern have greatly contributed to the increased prevalence of obesity and accelerated the spread of the T2DM epidemic worldwide, a better understanding of gene-diet interactions in T2DM will be useful for disease prediction and prevention. Here, we demonstrate that polymorphisms in the gene encoding GLUT10 are associated with a T2DM intermediate phenotype in non-diabetic human subjects. Additionally, mice that carry a GLUT10 rare variant have reduced WAT development and are susceptible for HFD-induced T2DM. We further demonstrate that GLUT10 is highly expressed in preadipocytes, where it regulates intracellular ascorbic acid levels and ascorbic acid-dependent DNA demethylation to control adipogenesis. Preadipocytes carrying the GLUT10 rare variant or with knockdown of GLUT10 expression have reduced the adipogenesis. Thus, we are able to conclude that GLUT10 regulates adipogenesis via ascorbic acid-dependent DNA demethylation to affect WAT development and contribute to the sensitivity of HFD-induced metabolic dysregulation.

TRI-PONDERAL MASS INDEX IS USEFUL FOR SCREENING CHILDREN AND ADOLESCENTS WITH INSULIN RESISTANCE

Objective:

To investigate whether tri-ponderal mass index and body mass index Z scores are equivalent for screening children and adolescents with insulin resistance.

Methods:

Cross-sectional study with 296 children and adolescents enrolled at public schools of Vitória, Espírito Santo, Brazil, aged eight to 14 years. The tri-ponderal mass index was calculated as the ratio between weight and height cubed. The body mass index was calculated as the ratio between weight and height squared. Insulin resistance was defined with the homeostatic model assessment (HOMA-IR).

Results:

The HOMA-IR was higher in the 4^th quartile of body mass index Z scores and tri-ponderal mass index compared to 1^st and 2^nd quartiles for both girls and boys. The areas under the age-adjusted receiver operating characteristic curves were similar between the indices for girls (body mass index Z scores=0.756; tri-ponderal mass index=0.763) and boys (body mass index Z scores=0.831; tri-ponderal mass index=0.843). In addition, according to the simple linear regression analyses estimations, both body mass index Z scores and tri-ponderal mass index explained a significant fraction of the homeostatic model assessment variability for girls (body mass index Z scores: R²=0.269; tri-ponderal mass index: R²=0.289; p<0.001) and boys (body mass index Z scores: R²=0.175; tri-ponderal mass index: R²=0.210; p<0.001).

Conclusions:

The tri-ponderal mass index and body mass index Z scores were similar to discriminate children and adolescents with insulin resistance. It is noteworthy that the use of tri-ponderal mass index is clearly advantageous, because it can be calculated with no concerns on adjustments for the age, a fact that makes it very applicable in the clinical practice.

PCB126 blocks the thermogenic beiging response of adipocytes

Subcutaneous white adipose tissue is capable of becoming thermogenic in a process that is referred to as "beiging." Beiging is associated with activation of the uncoupling protein, UCP1, and is known to be important for preventing adipose hypertrophy and development of insulin resistance. Polychlorinated biphenyls (PCBs) accumulate in fat, and it is hypothesized that disruption of adipogenesis and adipocyte function by PCBs may be causative in the development of obesity and diabetes. We developed immortal human subcutaneous preadipocytes that, when differentiated, are capable of beiging. Preadipocytes that were treated with polychlorinated biphenyl congener 126 (PCB126), followed by differentiation, were suppressed for their ability to activate UCP1 upon β-adrenergic stimulation with norepinephrine (NE), demonstrating a block in the beiging response. Treatment of preadipocytes with another known endogenous AhR agonist, indoxyl sulfate (IS), followed by differentiation also blocked the NE-stimulated upregulation of UCP1. Knockdown of the aryl hydrocarbon receptor (AhR) caused the preadipocytes to be refractory to PCB126 and IS effects. The chemical AhR antagonist, CH223191, was effective at preventing the effects of PCB126 but not IS, indicating AhR ligand specificity of CH223191. Repression of NE-induced UCP1 upregulation was also observed when already-differentiated mature adipocytes were treated with PCB126 but not IS. These results indicate that exposure of preadipocytes to endogenous (IS) or exogenous (PCB126) AhR agonists is effective at blocking them from becoming functional adipocytes that are capable of the beiging response. Mature adipocytes may have differential responses. This finding suggests a mechanism by which dioxin-like PCBs such as PCB126 could lead to disruption in energy homeostasis, potentially leading to obesity and diabetes.

No Influence of Overweight/Obesity on Exercise Lipid Oxidation: A Systematic Review

Compared to lean counterparts, overweight/obese individuals rely less on lipid during fasting. This deficiency has been implicated in the association between overweight/obesity and blunted insulin signaling via elevated intramuscular triglycerides. However, the capacity for overweight/obese individuals to use lipid during exercise is unclear. This review was conducted to formulate a consensus regarding the influence of overweight/obesity on exercise lipid use. PubMed, ProQuest, ISI Web of Science, and Cochrane Library databases were searched. Articles were included if they presented original research on the influence of overweight/obesity on exercise fuel use in generally healthy sedentary adults. Articles were excluded if they assessed older adults, individuals with chronic disease, and/or exercise limitations or physically-active individuals. The search identified 1205 articles with 729 considered for inclusion after duplicate removal. Once titles, abstracts, and/or manuscripts were assessed, 24 articles were included. The preponderance of evidence from these articles indicates that overweight/obese individuals rely on lipid to a similar extent during exercise. However, conflicting findings were found in eight articles due to the outcome measure cited, participant characteristics other than overweight/obesity and characteristics of the exercise bout(s). We also identified factors other than body fatness which can influence exercise lipid oxidation that should be controlled in future research.

Agreement between software programmes of body composition analyses on abdominal computed tomography scans of obese adults

Objective A large number of studies have used abdominal computed tomography (CT) to quantify body composition, and different software programmes have been used to perform these analyses. Thus, this comparison is important to enable researchers to know the performance of more accessible software. Subjects and methods Fifty-four abdominal CT scans of obese (BMI 30 to 39.9 kg/m2), sedentary adults (24-41 years) patients from a Brazilian single center were selected. Two software programs were compared: Slice-O-Matic (Tomovision, Canada) version 5.0 and OsiriX version 5.8.5. The body composition analysis were segmented using standard Hounsfield unit (HU) (adipose tissue: -190 to +30 and skeletal muscle: -29 to +150) and measured at the mid third lumbar vertebra (L3) level on a slice showing both transversal processes. Bland-Altman limits of agreement analyses were used to assess the level of agreement between Slice-O-Matic and OsiriX. Results A total of fifty-four participants were evaluated, with majority women (69%), mean of age 31.3 (SD 6.5) years and obesity grade I most prevalent (74.1%). The agreement, in Bland-Altman analysis, between Slice-O-Matic and OsiriX analisys for the muscle mass tissue, visceral adipose tissue and subcutaneous adipose tissue were excellent (≥ 0.954) with P-values < 0.001. Conclusion These findings show that Slice-O-Matic and OsiriX softwares agreement in measurements of skeletal muscle and adipose tissue and sarcopenia diagnosis in obese patients, suggesting good applicability in studies with body composition in this population and clinical practice.

Inter and intra-reliability of ultrasonography for the measurement of abdominal subcutaneous & visceral adipose tissue thickness at 12 weeks gestation

BACKGROUND

Excess abdominal adiposity cause metabolic disturbances, particularly in pregnancy. Methods of accurate measurement are limited in pregnancy due to risks associated with these procedures. This study outlines a non-invasive methodology for the measurement of adipose tissue in pregnancy and determines the intra- and inter-observer reliability of ultrasound (US) measurements of the two components of adipose tissue (subcutaneous (SAT) and visceral adipose tissue (VAT)) within a pregnant population.

METHODS

Thirty pregnant women were recruited at the end of their first trimester, from routine antenatal clinic at the University Maternity Hospital Limerick, Ireland. Measurements of adipose tissue thickness were obtained using a GE Voluson E8 employing a 1-5 MHz curvilinear array transducer. Two observers, employing methodological rigour in US technique, measured thickness of adipose tissue three times, and segmented the US image systematically in order to define measurements of SAT and VAT using specifically pre-defined anatomical landmarks.

RESULTS

Intra-observer and inter-observer precision was assessed using Coefficient of Variation (CV). Measurements of SAT and total adipose for both observers were < 5% CV and < 10% CV for VAT in measures by both observers. Inter-observer reliability was assessed by Limits of Agreement (LoA). LoA were determined to be - 0.45 to 0.46 cm for SAT and - 0.34 to 0.53 cm for VAT values. Systematic bias of SAT measurement was 0.01 cm and 0.10 cm for VAT. Inter-observer precision was also assessed by coefficient of variation (CV: SAT, 3.1%; VAT, 7.2%; Total adipose, 3.0%).

CONCLUSION

Intra-observer precision was found to be acceptable for measures of SAT, VAT and total adipose according to anthropometric criterion, with higher precision reported in SAT values than in VAT. Inter-observer reliability assessed by Limits-Of-Agreement (LoA) confirm anthropometrically reliable to 0.5 cm. Systematic bias was minimal for both measures, falling within 95% confidence intervals. These results suggest that US can produce reliable, repeatable and accurate measures of SAT and VAT during pregnancy.

Abdominal adiposity and cardiometabolic risk factors in children and adolescents: a Mendelian randomization analysis

BACKGROUND

Mendelian randomization studies in adults suggest that abdominal adiposity is causally associated with increased risk of type 2 diabetes and coronary artery disease in adults, but its causal effect on cardiometabolic risk in children remains unclear.

OBJECTIVE

We aimed to study the causal relation of abdominal adiposity with cardiometabolic risk factors in children by applying Mendelian randomization.

METHODS

We constructed a genetic risk score (GRS) using variants previously associated with waist-to-hip ratio adjusted for BMI (WHRadjBMI) and examined its associations with cardiometabolic factors by linear regression and Mendelian randomization in a meta-analysis of 6 cohorts, including 9895 European children and adolescents aged 3-17 y.

RESULTS

WHRadjBMI GRS was associated with higher WHRadjBMI (β = 0.021 SD/allele; 95% CI: 0.016, 0.026 SD/allele; P = 3 × 10-15) and with unfavorable concentrations of blood lipids (higher LDL cholesterol: β = 0.006 SD/allele; 95% CI: 0.001, 0.011 SD/allele; P = 0.025; lower HDL cholesterol: β = -0.007 SD/allele; 95% CI: -0.012, -0.002 SD/allele; P = 0.009; higher triglycerides: β = 0.007 SD/allele; 95% CI: 0.002, 0.012 SD/allele; P = 0.006). No differences were detected between prepubertal and pubertal/postpubertal children. The WHRadjBMI GRS had a stronger association with fasting insulin in children and adolescents with overweight/obesity (β = 0.016 SD/allele; 95% CI: 0.001, 0.032 SD/allele; P = 0.037) than in those with normal weight (β = -0.002 SD/allele; 95% CI: -0.010, 0.006 SD/allele; P = 0.605) (P for difference = 0.034). In a 2-stage least-squares regression analysis, each genetically instrumented 1-SD increase in WHRadjBMI increased circulating triglycerides by 0.17 mmol/L (0.35 SD, P = 0.040), suggesting that the relation between abdominal adiposity and circulating triglycerides may be causal.

CONCLUSIONS

Abdominal adiposity may have a causal, unfavorable effect on plasma triglycerides and potentially other cardiometabolic risk factors starting in childhood. The results highlight the importance of early weight management through healthy dietary habits and physically active lifestyle among children with a tendency for abdominal adiposity.

Brown adipocytes from induced pluripotent stem cells-how far have we come?

A global increase in the number of individuals who are either overweight or obese is leading to a higher incidence of type 2 diabetes (T2D). Behavioral interventions for the treatment of obesity have yet to deliver desired outcomes, thus introducing a pressing need for molecular- and cellular-based therapies. Excess energy from food is stored in the form of triglycerides in white adipose tissue, which expands during weight gain and can lead to insulin resistance and T2D. By contrast, brown adipose tissue (BAT) releases energy from metabolic substrates in the form of heat and secretes factors that can reverse metabolic disease by acting systemically. Therefore, the ability to increase BAT activity is a promising approach to improve energy balance and metabolic homeostasis. Methods are now being developed to generate brown adipocytes from human induced pluripotent stem cells (hiPSCs), which would (1) provide an unlimited source of cellular material to study human brown adipogenesis, and (2) could be used to develop drug- and cell-based therapies for the treatment of metabolic complications associated with obesity. This article reviews basic BAT biology and details the current progress toward developing brown adipocytes from hiPSCs.

Evaluation of neck circumference as an easy and reliable predictor for non-alcoholic fatty liver disease

BACKGROUND/AIMS

The aim of the present study was to investigate the relationship between non-alcoholic fatty liver disease (NAFLD) and neck circumference (NC) and to compare the NC predictive value with other anthropometric indices in the prediction of NAFLD and metabolic syndrome (MetS) as well as to find the NC cut-off point for the prediction of NAFLD and MetS in an Iranian population.

MATERIALS AND METHODS

A total of 590 individuals who fulfilled our criteria were enrolled in the study. Anthropometric measurements, physical examinations, and abdominal ultrasonography were performed by trained staff. Blood samples for biochemical tests were also obtained after fasting for 12 h.

RESULTS

Neck circumference was associated with NAFLD and MetS in both genders (p<0.0001) and remained significant even after adjustment for possible confounding factors. It was also significantly associated with other anthropometric indices, such as fatty liver severity, aspartate aminotransferase, alanine aminotransferase, fasting blood sugar, triglycerides, low-density lipoprotein, systolic and diastolic blood pressure, and family history of diabetes in both sexes (p<0.05). There was a significant negative correlation between high-density lipoprotein levels and NC in both sexes (p<0.001).

CONCLUSION

Neck circumference was significantly correlated with NAFLD and MetS. In addition, it had the highest predictive value for NAFLD and MetS among other common anthropometric indices. Therefore, it can be used as a simple and feasible tool for screening NAFLD in a large population.

Acute effects of active breaks during prolonged sitting on subcutaneous adipose tissue gene expression: an ancillary analysis of a randomised controlled trial

Active breaks in prolonged sitting has beneficial impacts on cardiometabolic risk biomarkers. The molecular mechanisms include regulation of skeletal muscle gene and protein expression controlling metabolic, inflammatory and cell development pathways. An active communication network exists between adipose and muscle tissue, but the effect of active breaks in prolonged sitting on adipose tissue have not been investigated. This study characterized the acute transcriptional events induced in adipose tissue by regular active breaks during prolonged sitting. We studied 8 overweight/obese adults participating in an acute randomized three-intervention crossover trial. Interventions were performed in the postprandial state and included: (i) prolonged uninterrupted sitting; or prolonged sitting interrupted with 2-minute bouts of (ii) light- or (iii) moderate-intensity treadmill walking every 20 minutes. Subcutaneous adipose tissue biopsies were obtained after each condition. Microarrays identified 36 differentially expressed genes between the three conditions (fold change ≥0.5 in either direction; p < 0.05). Pathway analysis indicated that breaking up of prolonged sitting led to differential regulation of adipose tissue metabolic networks and inflammatory pathways, increased insulin signaling, modulation of adipocyte cell cycle, and facilitated cross-talk between adipose tissue and other organs. This study provides preliminary insight into the adipose tissue regulatory systems that may contribute to the physiological effects of interrupting prolonged sitting.

The discriminatory power of visceral adipose tissue area vs anthropometric measures as a diagnostic marker for metabolic syndrome in South African women

BACKGROUND

A number of studies have shown central adiposity, in particular visceral adipose tissue (VAT) accumulation to be a hallmark of metabolic syndrome (MetS). In clinical practice, waist circumference (WC) is used as a proxy for VAT.

AIM

To compare the ability of dual energy x-ray absorptiometry (DXA)-derived VAT area and anthropometric measures of adiposity for diagnosing MetS in a sample of high risk South African women.

METHODS

MetS was quantified using the Joint Interim Statement (JIS) criteria. Fasting glucose, insulin and lipid profile were measured in 204 post-menopausal women. Anthropometry measures included body mass index (BMI), WC, waist-to-hip ratio (WHR), waist-to-height ratio (WHtR) and a body shape index (ABSI). The area under the curve (AUC) was used to assess their performance in detecting any two components of MetS (excluding WC). Optimal WC and VAT area cut-points were derived to compare their performance for diagnosing MetS and to compare to internationally recognised cut-points.

RESULTS

The highest AUC for the prediction of MetS was recorded for VAT, followed by WHtR and WC (AUC, 0.767, 0.747 and 0.738 respectively), but these did not differ significantly (all p ≥ 0.192). In contrast, VAT was significantly better than BMI (p = 0.028), hip (p = 0.0004) and ABSI (p < 0.0001). The optimal WC (94.4 cm) and VAT area (174 cm² based on the Youden's index method and 175.50 cm² based on the CTL approach) cut-points performed similarly in detecting MetS.

CONCLUSION

DXA-derived VAT and WC had the same overall performance in discriminating the presence of any 2 MetS components in high risk South African women. These findings support the current recommendations of using WC rather than VAT for MetS risk screening, as it is cheap, accessible and easy to measure.

Contribution of Adipose Tissue Inflammation to the Development of Type 2 Diabetes Mellitus

The objective of this comprehensive review is to summarize and discuss the available evidence of how adipose tissue inflammation affects insulin sensitivity and glucose tolerance. Low-grade, chronic adipose tissue inflammation is characterized by infiltration of macrophages and other immune cell populations into adipose tissue, and a shift toward more proinflammatory subtypes of leukocytes. The infiltration of proinflammatory cells in adipose tissue is associated with an increased production of key chemokines such as C-C motif chemokine ligand 2, proinflammatory cytokines including tumor necrosis factor α and interleukins 1β and 6 as well as reduced expression of the key insulin-sensitizing adipokine, adiponectin. In both rodent models and humans, adipose tissue inflammation is consistently associated with excess fat mass and insulin resistance. In humans, associations with insulin resistance are stronger and more consistent for inflammation in visceral as opposed to subcutaneous fat. Further, genetic alterations in mouse models of obesity that reduce adipose tissue inflammation are-almost without exception-associated with improved insulin sensitivity. However, a dissociation between adipose tissue inflammation and insulin resistance can be observed in very few rodent models of obesity as well as in humans following bariatric surgery- or low-calorie-diet-induced weight loss, illustrating that the etiology of insulin resistance is multifactorial. Taken together, adipose tissue inflammation is a key factor in the development of insulin resistance and type 2 diabetes in obesity, along with other factors that likely include inflammation and fat accumulation in other metabolically active tissues. © 2019 American Physiological Society. Compr Physiol 9:1-58, 2019.

Differential open chromatin profile and transcriptomic signature define depot-specific human subcutaneous preadipocytes: primary outcomes

Background

Increased lower body fat is associated with reduced cardiometabolic risk. The molecular basis for depot-specific differences in gluteofemoral (GF) compared with abdominal (A) subcutaneous adipocyte function is poorly understood. In the current report, we used a combination of Assay for Transposase-Accessible Chromatin followed by sequencing (ATAC-seq), RNA-seq, and chromatin immunoprecipitation (ChIP)-qPCR analyses that provide evidence that depot-specific gene expression patterns are associated with differential epigenetic chromatin signatures.

Methods

Preadipocytes cultured from A and GF adipose tissue obtained from premenopausal apple-shaped women were used to perform transcriptome analysis by RNA-seq and assess accessible chromatin regions by ATAC-seq. We measured mRNA expression and performed ChIP-qPCR experiments for histone modifications of active (H3K4me3) and repressed chromatin (H3K27me3) regions respectively on the promoter regions of differentially expressed genes.

Results

RNA-seq experiments revealed an A-fat and GF-fat selective gene expression signature, with 126 genes upregulated in abdominal preadipocytes and 90 genes upregulated in GF cells. ATAC-seq identified almost 10-times more A-specific chromatin-accessible regions. Using a combined analysis of ATAC-seq and global gene expression data, we identified 74 of the 126 abdominal-specific genes (59%) with A-specific accessible chromatin sites within 200 kb of the transcription start site (TSS), including HOXA3, HOXA5, IL8, IL1b, and IL6. Interestingly, only 14 of the 90 GF-specific genes (15%) had GF-specific accessible chromatin sites within 200 kb of the corresponding TSS, including HOXC13 and HOTAIR, whereas 25 of them (28%) had abdominal-specific accessible chromatin sites. ChIP-qPCR experiments confirmed that the active H3K4me3 chromatin mark was significantly enriched at the promoter regions of HOXA5 and HOXA3 genes in abdominal preadipocytes, while H3K27me3 was less abundant relative to chromatin from GF. This is consistent with their A-fat specific gene expression pattern. Conversely, analysis of the promoter regions of the GF specific HOTAIR and HOXC13 genes exhibited high H3K4me3 and low H3K27me3 levels in GF chromatin compared to A chromatin.

Conclusions

Global transcriptome and open chromatin analyses of depot-specific preadipocytes identified their gene expression signature and differential open chromatin profile. Interestingly, A-fat-specific open chromatin regions can be observed in the proximity of GF-fat genes, but not vice versa.

Trial registration

Clinicaltrials.gov, NCT01745471. Registered 5 December 2012.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0582-0) contains supplementary material, which is available to authorized users.

Subcutaneous adipose tissue imaging of human obesity reveals two types of adipocyte membranes: Insulin-responsive and -nonresponsive

In adipose tissue, resistance to insulin's ability to increase glucose uptake can be induced by multiple factors, including obesity. Impaired insulin action may take place at different spatial loci at the cellular or subcellular level. To begin to understand the spatial response to insulin in human subcutaneous adipose tissue (hSAT), we developed a quantitative imaging method for activation of a major signaling node in the glucoregulatory insulin signaling pathway. After treatment with insulin or control media, biopsied tissues were immunostained for Akt phosphorylation at Thr-308/9 (pAkt) and then imaged by confocal fluorescence microscopy automated to collect a large grid of high resolution fields. In hSAT from 40 men and women with obesity, substantial heterogeneity of pAkt densities in adipocyte membranes were quantified in each image mosaic using a spatial unit of at least twice the size of the point spread function. Statistical analysis of the distribution of pAkt spatial units was best fit as the weighted sum of two separate distributions, corresponding to either a low or high pAkt density. A "high pAkt fraction" metric was calculated from the fraction of high pAkt distributed units over the total units. Importantly, upon insulin stimulation, tissues from the same biopsy showed either a minimal or a substantial change in the high pAkt fraction. Further supporting a two-state response to insulin stimulation, subjects with similar insulin sensitivity indices are also segregated into either of two clusters identified by the amount of membrane-localized pAkt.

A delayed proinflammatory response of human preadipocytes to PCB126 is dependent on the aryl hydrocarbon receptor

Inflammation in adipose tissue is recognized as a causative factor in the development of type II diabetes. Adipocyte hypertrophy as well as bacterial and environmental factors have been implicated in causing inflammation in mature adipocytes. Exposure to persistent organic pollutants such as polychlorinated biphenyls (PCBs) has been associated with the development of type II diabetes. We show here that PCB126, a dioxin-like PCB, activates a robust proinflammatory state in fat cell precursors (preadipocytes). The response was found to be dependent on aryl hydrocarbon receptor (AhR) activation, although induction of the response was delayed compared to upregulation of CYP1A1, a classic AhR-responsive gene. Treatment of preadipocytes with a nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) inhibitor partially attenuated the PCB126-induced inflammatory response and partly, but not completely, ameliorated disruption of adipogenesis caused by PCB126. Our results indicate a role for PCB126 in mediating an inflammatory response through AhR in preadipocytes that interferes with adipogenesis.

Chest adipose tissue distribution in patients with morbid obesity

Purpose

Obesity is a well-known of risk factor for atherosclerosis and the amount of visceral adipose tissue is considered as an independent predictor of coronary artery disease (CAD). An aim of the study was to investigate the distribution of intrathoracic adipose tissue in morbidly obese patients.

Material and methods

Fifty-one patients with morbid obesity (BMI ≥ 40 kg/m²) and thirty controls were scanned in a coronary calcium scoring protocol. Control group consisted of patients scanned due to a clinical suspicion of CAD, who did not fulfill obesity criteria. The amount of adipose tissue was measured as epicardial adipose tissue (EAT) thickness, pericoronary fat (PCF) thickness, total intra-pericardial fat (IPF) volume, and total intrathoracic fat (ITF) volume.

Results

Mean BMI of obese patients and controls was 47.3 and 26.5, respectively (p < 0.0001). Patients with obesity and controls did not differ with respect to mean EAT, mean PCF, and IPF. However, ITF was lower in obesity group than in control group (268 vs. 332 cm³, respectively; p < 0.03). Moreover, ROC analysis presented relation between obesity and the superior EAT thickness, PCF at LCX, mean PCF, ITF, and chest soft tissue (CST) thickness (p < 0.03). CST thickness of > 60 mm was the parameter that presented the strongest association with morbid obesity (AUC 0.95; p < 0.0001).

Conlcusions

Increased chest soft tissue thickness but not the increased intrathoracic adipose tissue volume was associated with morbid obesity. Since the quantity of the pericardiac fat is not directly related to the obesity, its accumulation may be related to a mechanism different than that of subcutaneous adipose tissue growth.

Associations of Abdominal Subcutaneous and Visceral Fat with Insulin Resistance and Secretion Differ Between Men and Women: The Netherlands Epidemiology of Obesity Study

BACKGROUND

Abdominal obesity is a well-established risk factor for the development of type 2 diabetes. However, sex differences may exist. We aimed to investigate the associations of abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) with insulin resistance and insulin secretion in men and women.

METHODS

In this cross-sectional analysis of the Netherlands Epidemiology of Obesity study, fasting and postprandial concentrations of glucose and insulin were measured and abdominal fat depots were assessed using magnetic resonance imaging in 2253 participants (53% women). With linear regression analysis, we examined associations of abdominal SAT and VAT with measures of insulin resistance and insulin secretion in men and women, while adjusting for age, ethnicity, education, smoking habits, alcohol consumption, menopausal state and hormone use in women, and models with VAT additionally for total body fat.

RESULTS

Participants had a mean [standard deviation (SD)] age of 56 (6) years, body mass index: 25.9 (3.9) kg/m², VAT: 89 (55) cm², and SAT: 235 (95) cm². In the multivariate models in men, per SD of VAT the homeostatic model assessment of insulin resistance (HOMA-IR) was 20% (95% CI: 14-26) higher, and per SD SAT 21% (15-27) higher. In women, per SD of VAT the HOMA-IR was 40% (29-52) higher, and per SD SAT 12% (6-19) higher. Associations with measures of insulin secretion were weaker than with insulin resistance.

CONCLUSIONS

In men, abdominal SAT and VAT were associated with insulin resistance to a similar extent, whereas in women particularly VAT was associated with insulin resistance and insulin secretion. Future studies need to unravel the mechanisms underlying the metabolic effects of visceral fat in women. Simple and less expensive measures that can distinct abdominal subcutaneous and visceral fat are needed for an improved metabolic risk stratification.

Scaffold-free generation of uniform adipose spheroids for metabolism research and drug discovery

Adipose tissue dysfunction is critical to the development of type II diabetes and other metabolic diseases. While monolayer cell culture has been useful for studying fat biology, 2D culture often does not reflect the complexity of fat tissue. Animal models are also problematic in that they are expensive, time consuming, and may not completely recapitulate human biology because of species variation. To address these problems, we have developed a scaffold-free method to generate 3D adipose spheroids from primary or immortal human or mouse pre-adipocytes. Pre-adipocytes self-organize into spheroids in hanging drops and upon transfer to low attachment plates, can be maintained in long-term cultures. Upon exposure to differentiation cues, the cells mature into adipocytes, accumulating large lipid droplets that expand with time. The 3D spheroids express and secrete higher levels of adiponectin compared to 2D culture and respond to stress, either culture-related or toxin-associated, by secreting pro-inflammatory adipokines. In addition, 3D spheroids derived from brown adipose tissue (BAT) retain expression of BAT markers better than 2D cultures derived from the same tissue. Thus, this model can be used to study both the maturation of pre-adipocytes or the function of mature adipocytes in a 3D culture environment.

Schisandrin B regulates lipid metabolism in subcutaneous adipocytes

Subcutaneous adipocytes in obese subjects have a lower sensitivity to catecholamine-induced lipolysis and a higher sensitivity to insulin anti-lipolytic effects compared to adipocytes in other adipose depots. Therefore, increasing lipolysis in subcutaneous adipocytes coupled with enhanced fatty acid oxidation may be an anti-obesity strategy. Schisandrin B (Sch B) is one of the most abundant active dibenzocyclooctadiene derivatives found in the fruit of Schisandra chinensis which is a commonly prescribed Chinese medicinal herb. We found that Sch B reduced glycerolipid contents in 3T3-L1 adipocytes and subcutaneous adipocytes dissected from DIO mice. Sch B also activated hormone sensitive lipase (HSL) and increased lipolysis in these adipocyte in a protein kinase A-dependent manner. Interestingly, Sch B increased fatty acid oxidation gene expressions in these adipocytes, implying an increase in fatty acid oxidation after treatment. In in vivo model, we found that Sch B increased HSL phosphorylation, reduced glycerolipid levels and increased fatty acid oxidation gene expressions in the subcutaneous adipocytes in the DIO mice. More importantly, Sch B significantly reduced the subcutaneous adipocyte sizes, subcutaneous adipose tissue mass and body weight of the mice. Our study provides scientific evidence to suggest a potential therapeutic function of Sch B or Schisandra chinensis seed containing Sch B in reducing obesity.

Enriching Diet with n-3 PUFAs to Help Prevent Cardiovascular Diseases in Healthy Adults: Results from Clinical Trials

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are believed to be important for cardiovascular health. Many investigations have been carried out in an attempt to examine the effect of n-3 PUFAs intake, in the form of supplementation or fortified foods, for the management of cardiovascular disease (CVD) and risk factors for CVD, whereas less is known about the effect on healthy individuals. The present study reviews the available literature in order to examine the relationship between n-3 PUFAs intake, either via supplementation or enriched food, and the prevention of CVD among healthy adults. Interventional clinical trials on subjects aged >18 years old with none of the established risk factors for CVD have been considered for review. n-3 PUFAs supplementation or enriched food may positively regulate triglycerides and some lipoprotein subsets, as well as several vascular and coagulation parameters, even in healthy patients, presenting no risk factors for CVD, suggesting a protective effect. Diet enrichment with omega-3 is likely to be useful in helping to lower the risk of developing CVD in healthy individuals, but still offers no strong evidence of a tangible benefit on a population level. Additional studies are needed to determine the optimal daily intake, especially to prevent the unfavorable effects of PUFAs over-consumption.

Hypertriglyceridemic Waist Phenotype and Changes in the Fasting Glycemia and Blood Pressure in Children and Adolescents Over One-Year Follow-Up Period

BACKGROUND:

The hypertriglyceridemic waist (HTW) phenotype is defined as the simultaneous presence of increased waist circumference (WC) and serum triglycerides (TG) levels and it has been associated with cardiometabolic risk in children and adolescents.

OBJECTIVE:

The objective was to evaluate the influence of HTW phenotype in the fasting glycemia and blood pressure in children and adolescents over one-year follow-up period.

METHODS:

It is a cohort study involving 492 children and adolescents from 7 to 15 years old, both genders, who were submitted to anthropometric, biochemical and clinical evaluation at the baseline, and also after 6 and 12 months of follow-up. Generalized Estimating Equation (GEE) models were calculated to evaluate the longitudinal influence of the HTW phenotype in the glycemia and blood pressure over one-year.

RESULTS:

It was observed a prevalence of 10.6% (n = 52) of HTW phenotype in the students. The GEE models identified that students with HTW phenotype had an increase of 3.87 mg/dl in the fasting glycemia mean (CI: 1.68-6.05) and of 3.67mmHg in the systolic blood pressure (SBP) mean (CI: 1.55-6.08) over one-year follow-up, after adjusting for confounding variables.

CONCLUSIONS:

The results of this study suggest that HTW phenotype is a risk factor for longitudinal changes in glycemia and SBP in children and adolescents over one-year follow-up period.

FUNDAMENTO:

O fenótipo de cintura hipertrigliceridêmica (CHT) é definido como a presença simultânea de circunferência de cintura (CC) e níveis séricos de triglicérides (TG) aumentados e tem sido associado com risco cardiometabólico em crianças e adolescentes.

OBJETIVO:

Avaliar a influência do fenótipo CHT na glicemia de jejum e na pressão arterial em crianças e adolescentes em um período de acompanhamento de um ano.

MÉTODOS:

Trata-se de um estudo de coorte envolvendo 492 crianças e adolescentes de 7 a 15 anos de ambos os sexos, que foram submetidos à avaliação antropométrica, bioquímica e clínica no início e também após 6 e 12 meses de seguimento. Os modelos de Equação de Estimulação Generalizada (GEE) foram calculados para avaliar a influência longitudinal do fenótipo CHT na glicemia e na pressão arterial ao longo de um ano.

RESULTADOS:

Foi observada uma prevalência de 10,6% (n = 52) do fenótipo CHT nos estudantes. Os modelos GEE identificaram que os estudantes com fenótipo CHT apresentaram aumento de 3,87 mg/dl na média de glicemia em jejum (IC: 1,68-6,05) e de 3,67 mmHg na pressão arterial sistólica media (PAS) (IC: 1,55-6,08) depois de um ano de acompanhamento, após ajuste para variáveis de confusão.

CONCLUSÕES:

Os resultados deste estudo sugerem que o fenótipo CHT é um fator de risco para alterações longitudinais da glicemia e da PAS em crianças e adolescentes em um período de um ano de seguimento.