Abdominal subcutaneous and visceral adipose tissue and insulin resistance in the Framingham heart study

Insulin-resistance in paediatric age: Its magnitude and implications

Insulin resistance (IR) is insulin failure in normal plasma levels to adequately stimulate glucose uptake by the peripheral tissues. IR is becoming more common in children and adolescents than before. There is a strong association between obesity in children and adolescents, IR, and the metabolic syndrome components. IR shows marked variation among different races, crucial to understanding the possible cardiovascular risk, specifically in high-risk races or ethnic groups. Genetic causes of IR include insulin receptor mutations, mutations that stimulate autoantibody production against insulin receptors, or mutations that induce the formation of abnormal glucose transporter 4 molecules or plasma cell membrane glycoprotein-1 molecules; all induce abnormal energy pathways and end with the development of IR. The parallel increase of IR syndrome with the dramatic increase in the rate of obesity among children in the last few decades indicates the importance of environmental factors in increasing the rate of IR. Most patients with IR do not develop diabetes mellitus (DM) type-II. However, IR is a crucial risk factor to develop DM type-II in children. Diagnostic standards for IR in children are not yet established due to various causes. Direct measures of insulin sensitivity include the hyperinsulinemia euglycemic glucose clamp and the insulin-suppression test. Minimal model analysis of frequently sampled intravenous glucose tolerance test and oral glucose tolerance test provide an indirect estimate of metabolic insulin sensitivity/resistance. The main aim of the treatment of IR in children is to prevent the progression of compensated IR to decompensated IR, enhance insulin sensitivity, and treat possible complications. There are three main lines for treatment: Lifestyle and behavior modification, pharmacotherapy, and surgery. This review will discuss the magnitude, implications, diagnosis, and treatment of IR in children.

Association between changes in body weight and cardiovascular disease risk factors among obese Japanese patients with type 2 diabetes

Aims/Introduction

We aimed to assess the association between bodyweight reduction and cardiovascular disease risk factors, and to identify the minimum bodyweight reduction associated with significant improvement in cardiovascular disease risk factors among obese Japanese patients with type 2 diabetes.

Materials and Methods

The cohort comprised 1,753 patients with type 2 diabetes and body mass index ≥25 kg/m², who visited our clinic between 2013 and 2016. Multivariable linear regression analysis was carried out to assess the relationship between bodyweight changes and glycated hemoglobin A1c, serum lipids and blood pressure. Analyses of covariance were carried out to compare mean changes in cardiovascular disease risk factors across six groups of bodyweight change, <−5%, −5% to <−3%, −3% to <−1%, −1% to <1% (reference), 1% to <3% and ≥3%.

Results

Log‐transformed bodyweight change had a significantly positive relationship with log‐transformed glycated hemoglobin A1c, triglycerides, low‐density lipoprotein cholesterol and systolic blood pressure changes, and a negative relationship with high‐density lipoprotein cholesterol, after adjusting for sex, age, duration of diabetes, body mass index, use of glucose‐lowering, lipid‐lowering and antihypertensive agents, and changes in the use of these medications. A mean change in glycated hemoglobin A1c was significantly improved only in the <−5% group compared with the reference. Mean changes in triglycerides were improved in all groups, and significantly in the <−5% group.

Conclusions

Bodyweight change was significantly associated with cardiovascular disease risk factor changes, and >5% bodyweight reduction was associated with improved glycated hemoglobin A1c.

Visceral Adipose Tissue and Non-alcoholic Fatty Liver Disease in Patients with Type 2 Diabetes

AIM

To explore the association of visceral adipose tissue (VAT) area and non-alcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM).

METHODS

This was a cross-sectional study comprising 100 patients with T2DM and 100 non-T2DM individuals, matched for age, sex, and body mass index (BMI). Transient elastography was used to assess hepatic steatosis and liver stiffness measurements (LSM). Controlled attenuation parameter (CAP) was used to quantify hepatic steatosis. To distinguish grades of hepatic steatosis, cutoff values were as follows: S1 ≥ 302, S2 ≥ 331, and S3 ≥ 337 dB/m. Moreover, VAT area was measured by dual-energy X-ray absorptiometry in accordance with validated protocols.

RESULTS

CAP score was significantly higher in participants with T2DM (294.61 ± 3.82 vs. 269.86 ± 3.86 dB/ m; P < 0.001). Furthermore, 42% of participants with T2DM had hepatic steatosis (S > S1: 302 dB/m), while this figure was 26% in non-T2DM group (P < 0.003). The mean liver stiffness measurement was also significantly higher in patients with T2DM (5.53 vs. 4.79 kPa; P < 0.001). VAT area was greater in patients with T2DM compared to non-T2DM individuals: 163.79 ± 47.98 cm² versus 147.49 ± 39.09 cm², P = 0.009. However, total and truncal fat mass were not different between the two groups. Age, BMI, waist circumference, ALT, CAP, and LSM were significantly associated with VAT area. BMI and VAT area were the important determinants of steatosis in both groups of participants with and without T2DM. Moreover, the VAT area was associated with the severity of hepatic steatosis and liver stiffness, independent of anthropometric measures of obesity.

CONCLUSION

VAT area is a major determinant of the severity of hepatic steatosis and liver stiffness in patient with T2DM.

Sirt3 Pharmacologically Promotes Insulin Sensitivity through PI3/AKT/mTOR and Their Downstream Pathway in Adipocytes

Sirtuin-3 (Sirt3) is a major mitochondrial deacetylase enzyme that regulates multiple metabolic pathways, and its expression is decreased in diabetes type 1 and type 2 diabetes. This study aimed to elucidate Sirt3′s molecular mechanism in regulating insulin sensitivity in adipocytes that can contribute to the effort of targeting Sirt3 for the treatment of obesity and type 2 diabetes. We found that the Sirt3 activator honokiol (HNK) induced adipogenesis compared to the control, in contrast to Sirt3 inhibitor, 3-TYP. Accordingly, HNK increased expression of adipocyte gene markers, gene-involved lipolysis and glucose transport (GLUT4), while 3-TYP reduced expression of those genes. Interestingly, 3-TYP caused an increase in gene expression of adipocyte-specific cytokines including IL6, resistin, and TNF-α. However, changes in adipocyte-specific cytokines in HNK treated cells were not significant. In addition, HNK stimulated insulin pathway by promoting insulin receptor beta (IRβ) and PI3K/AKT/mTOR pathways, resulting in an increase in phosphorylation of the forkhead family FoxO1/FoxO3a/FoxO4 and glycogen synthase kinase-3 (GSK-3β), opposing 3-TYP. In line with these findings, HNK increased free fatty acid and glucose uptake, contrary to 3-TYP. In conclusion, Sirt3 activator-HNK induced adipogenesis and lipolysis reduced adipocytes specific cytokines. Intriguingly, HNK activated insulin signaling pathway and increased free fatty acid as well as glucose uptake and transport, in sharp contrast to 3-TYP. These results indicate that, via insulin signaling regulation, Sirt3 activation by HNK improves insulin resistance, while Sirt3 inhibition by 3-TYP might precipitate insulin resistance.

Relationship between glucose homeostasis and obesity in early life-a study of Italian children and adolescents

Epidemic obesity is the most important risk factor for prediabetes and type 2 diabetes (T2D) in youth as it is in adults. Obesity shares pathophysiological mechanisms with T2D and is likely to share part of the genetic background. We aimed to test if weighted genetic risk scores (GRSs) for T2D, fasting glucose (FG) and fasting insulin (FI) predict glycaemic traits and if there is a causal relationship between obesity and impaired glucose metabolism in children and adolescents. Genotyping of 42 SNPs established by genome-wide association studies for T2D, FG and FI was performed in 1660 Italian youths aged between 2 and 19 years. We defined GRS for T2D, FG and FI and tested their effects on glycaemic traits, including FG, FI, indices of insulin resistance/beta cell function and body mass index (BMI). We evaluated causal relationships between obesity and FG/FI using one-sample Mendelian randomization analyses in both directions. GRS-FG was associated with FG (beta = 0.075 mmol/l, SE = 0.011, P = 1.58 × 10-11) and beta cell function (beta = -0.041, SE = 0.0090 P = 5.13 × 10-6). GRS-T2D also demonstrated an association with beta cell function (beta = -0.020, SE = 0.021 P = 0.030). We detected a causal effect of increased BMI on levels of FI in Italian youths (beta = 0.31 ln (pmol/l), 95%CI [0.078, 0.54], P = 0.0085), while there was no effect of FG/FI levels on BMI. Our results demonstrate that the glycaemic and T2D risk genetic variants contribute to higher FG and FI levels and decreased beta cell function in children and adolescents. The causal effects of adiposity on increased insulin resistance are detectable from childhood age.

Body Composition Predictors of Adverse Postoperative Events in Patients Undergoing Surgery for Long Bone Metastases

Body composition assessed using opportunistic CT has been recently identified as a predictor of outcome in patients with cancer. The purpose of this study was to determine whether the cross-sectional area (CSA) and the attenuation of abdominal subcutaneous adipose tissue, visceral adipose tissue (VAT), and paraspinous and abdominal muscles are the predictors of length of hospital stay, 30-day postoperative complications, and revision surgery in patients treated for long bone metastases.

Association of adiposity evaluated by anthropometric, BIA, and DXA measures with cardiometabolic risk factors in nonobese postmenopausal women: the CoLaus/OsteoLaus cohort

OBJECTIVE

After menopause, body composition changes with body fat accumulation, and an increase in cardiometabolic risk factors. Total fat mass, regional fat mass, and visceral adipose tissue (VAT) may be estimated with anthropometric measures, bioelectrical impedance analysis (BIA), and dual-energy X-ray absorptiometry (DXA). The aim of our study was to assess which measurement correlated best with cardiometabolic risk factors in healthy nonobese postmenopausal women.

METHODS

The CoLaus/OsteoLaus cohort included 1,500 postmenopausal women (age range 50-80). We analyzed correlations between: 1) measurements of body composition assessed by anthropometric measures, BIA, and DXA and 2) these measurements and different selected cardiometabolic risk factors, such as blood pressure, lipid markers (cholesterol subtypes and triglycerides), and metabolic markers (glucose, insulin, adiponectin, and leptin). Spearman correlation coefficient, stepwise forward regression, and linear regression analyses were used to determine association between anthropometric measurements and cardiometabolic risk factors.

RESULTS

In the 803 included participants (mean age 62.0 ± 7.1 y, mean body mass index 25.6 kg/m2 ± 4.4), correlations between total fat mass measured by BIA and total fat mass, android fat, gynoid fat, or VAT measured by DXA are very strong (from r = 0.531, [99% confidence interval (CI), 0.443-0.610] to r = 0.704, [99% CI, 0.640-0.758]). Body mass index and waist circumference have a higher correlation with VAT (r = 0.815, [99% CI, 0.772-0.851] and r = 0.823 [99% CI, 0.782-0.858], respectively) than BIA (r = 0.672 [99% CI, 0.603-0.731]). Among the anthropometric measurement and the measurements derived from DXA and BIA, VAT is the parameter most strongly associated with cardiometabolic risk factors. VAT better explains the variation of most of the cardiometabolic risk factors than age and treatment. For example, nearly 5% of the variability of the diastolic blood pressure (9.9 vs 4.9), nearly 15% of the variability of high-density lipoprotein cholesterol (20.3 vs 3.8) and triglyceride (21.1 vs 6.5), 25.3% of the variability of insulin (33.3 vs 8.1), and 37.5% of the variability of leptin (37.7 vs 1.1) were explained by VAT.

CONCLUSIONS

BIA seems not to be a good tool to assess VAT. At the population level, waist circumference and body mass index seem to be good tools to estimate VAT. VAT measured by DXA is the parameter most correlated with cardiometabolic risk factors and could become a component of the cardiometabolic marker on its own.

Association Between Visceral Adiposity Index and Insulin Resistance: A Cross-Sectional Study Based on US Adults

BACKGROUND

Visceral obesity index (VAI) is an empirical mathematical model used to evaluate the distribution and function of fat. Some studies have shown that VAI may be associated with the development of insulin resistance. In view of the differences in insulin resistance among different ethnic groups, this study attempts to analyze the special relationship between VAI and insulin resistance in American adults.

METHODS

We conducted a cross-sectional study through NHANES database. A total of 27309 patients over the age of 18 from the United States took part in the survey. It was divided into two groups: the IR-positive group and the IR-negative group. The association of VAI with IR was evaluated by logistic regression analyses mainly, including univariate analysis, multivariate regression analysis, curve fitting analysis and subgroup analysis.

RESULTS

The results showed that in the full-adjusted model, there is a strong positive association between VAI level and insulin resistance (OR: 1.28 (1.2~1.37), P<0.001) and there is a threshold effect.

CONCLUSIONS

This study suggests that higher VAI levels are associated with insulin resistance. VAI index may be used as a predictor of insulin resistance.

A performance review of novel adiposity indices for assessing insulin resistance in a pediatric Latino population

INTRODUCTION

Body mass index (BMI) percentile or BMI adjusted for age and sex is the most common anthropometric index to monitor and assess obesity in children. However, the ability of BMI to accurately predict insulin resistance (IR) in youth is debated. Determining the best method to noninvasively measure IR in the pediatric population is especially important due to the growing prevalence of type 2 diabetes mellitus (T2DM), which is more likely to develop in people with IR. Therefore, this study analyzed the performance of BMI against newer anthropometric indices in assessing IR in a pediatric Latino identifying sample.

METHODS

We studied 127 pediatric Latino participants from the Arizona Insulin Resistance (AIR) registry and performed linear regression analyses between various measures of IR and adiposity indices, including body mass index (BMI), triponderal mass index (TMI), body adiposity index (BAI), pediatric body adiposity index (pBAI), a body shape index (ABSI), abdominal volume index (AVI), waist to height ratio (WtHR) and waist to hip ratio (WHR). Log transformations of each index adjusted for age and sex and IR were used for the linear regressions. Additionally, we generated receiver operating characteristics (ROC) from logistic regressions between HOMA-IR and HOMA2IR against the same indices.

RESULTS

Using the homeostatic assessment of insulin resistance (HOMA-IR), HOMA2IR, the quantitative insulin-sensitivity check index (QUICKI), fasting serum insulin, and FPG/FSI to measure IR, we showed that BMI adjusted for age and sex performs similarly to many of the newer indices in our sample. The correlation coefficients for pBAI [R2: 0.27, 95% confidence interval: 0.88-1.81, p < 0.001] and BMI [R2: 0.27, 95% confidence interval: 0.92-1.92, p < 0.001] were the highest for HOMA-IR. Similarly, pBAI [R2: 0.29, 95% confidence interval: 0.88-1.72, p < 0.001] and BMI [R2: 0.29, 95% confidence interval: 0.93-1.83, p < 0.001] were the highest for HOMA2IR. A similar trend was observed with QUICKI, FSI, and FPG/FSI. ABSI had the lowest R ² value for all measures of IR. Area under the curve (AUC) values for the receiver operating characteristics (ROC) for HOMA-IR and HOMA2IR support these conclusions.

CONCLUSIONS

BMI adjusted for age and sex, despite its usage and simplicity, still stacks up well against newer indices in our Latino sample. Testing these indices across larger samples is necessary to generalize these findings and translate performance to adults.

Relationship Between Acyl and Desacyl Ghrelin Levels with Insulin Resistance and Body Fat Mass in Type 2 Diabetes Mellitus

PURPOSE

Although strong evidence suggests that ghrelin plays an important role in regulating energy balance, the effects of acylated ghrelin (AG) and deacylated ghrelin (DAG) on fat mass are largely undefined. This study aimed to investigate the differential associations of both forms of ghrelin with insulin resistance and body fat mass in patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

A total of 162 patients with type 2 diabetes were recruited and classified based on BMI and visceral fat area (VFA) as VFA normal group (n = 78), normal-BMI VFA obesity group (n = 20) and high-BMI VFA obesity group (n = 64). VFA and subcutaneous fat area (SFA) were detected by bioelectrical impedance analysis. Blood samples were collected to measure fasting glucose, insulin, lipids, AG and DAG levels after clinical examination.

RESULTS

Compared with VFA normal group, DAG levels were significantly lower (421.7 ± 106.0 and 388.7 ± 96.5 pg/mL vs 524.4 ± 141.5 pg/mL, P < 0.01) in the two VFA obesity groups. No significant difference was found in AG levels within three groups. Among all subjects, BMI, VFA, SFA, fasting insulin and HOMA-IR were negatively correlated with DAG but positively with AG/DAG ratio (P < 0.01). In contrast, AG was positively correlated with HOMA-IR and fasting glucose (P < 0.01). Multiple stepwise regression analysis showed that fasting glucose was the independent factor of AG, VFA and HOMA-IR were the independent factors related to DAG.

CONCLUSION

DAG levels have a strong negative association with excess body fat mass and insulin resistance, whereas AG levels are closely related to elevated blood glucose levels in T2DM patients.

Sex Differences in the Associations of Nutrient Patterns with Total and Regional Adiposity: A Study of Middle-Aged Black South African Men and Women

The study evaluated the association between nutrient patterns with body fat and regional adiposity in middle-aged black South African (SA) men and women and determined if this differed by sex. Body fat and regional adiposity (dual-energy x-ray absorptiometry), and dietary intake (7-day quantified food frequency questionnaire) were measured in black SA men (n = 414) and women (n = 346). Using principal component analysis, nutrient patterns were computed from 25 nutrients in the combined sample. Four nutrient patterns were extracted, explaining 67% of the variance in nutrient intake. Animal and fat, as well as the vitamin C, sugar, and potassium driven patterns, were positively associated with total adiposity. In contrast, the retinol and vitamin B12 pattern was associated with the centralisation of fat. Notably, the strength of the association between the animal-driven nutrient pattern and BMI was greater in men (1.14 kg/m², 95% CI (0.63–1.66)) than in women (0.81 kg/m², 95% CI (0.25–1.36)) (P_int = 0.017). In contrast, the plant-driven pattern was associated with higher abdominal subcutaneous adipose tissue (SAT) in women (44 cm², 95% CI (22–67)) but not men (P_int = 1.54 × 10⁻⁴). These differences suggest that although men and women have similar nutrient patterns, their associations with the whole body and regional body fat are different.

Exploring the Cell Stemness and the Complexity of the Adipose Tissue Niche

Adipose tissue is a complex organ composed of different cellular populations, including mesenchymal stem and progenitor cells, adipocytes, and immune cells such as macrophages and lymphocytes. These cellular populations alter dynamically during aging or as a response to pathophysiology such as obesity. Changes in the various inflammatory cells are associated with metabolic complications and the development of insulin resistance, indicating that immune cells crosstalk with the adipocytes. Therefore, a study of the cell populations in the adipose tissue and the extracellular matrix maintaining the tissue niche is important for the knowledge on the regulatory state of the organ. We used a combination of methods to study various parameters to identify the composition of the resident cells in the adipose tissue and evaluate their profile. We analyzed the tissue structure and cells based on histology, immune fluorescence staining, and flow cytometry of cells present in the tissue in vivo and these markers’ expression in vitro. Any shift in cells’ composition influences self-renewal of the mesenchymal progenitors, and other cells affect the functionality of adipogenesis.

Engineered mesoporous silica reduces long-term blood glucose, HbA1c, and improves metabolic parameters in prediabetics

Aim: To investigate the effect of oral consumption of engineered mesoporous silica particles, SiPore15^®, on long-term blood glucose levels and other metabolic parameters in individuals with prediabetes and newly diagnosed Type 2 diabetes. Method: An open-label, single-arm, multicenter trial was conducted in which SiPore15 was consumed three times daily for 12 weeks. Hemoglobin A1c (HbA1c, primary end point) and an array of metabolic parameters were measured at baseline and throughout the trial. Result: SiPore15 treatment significantly reduced HbA1c by a clinically meaningful degree and improved several disease-associated parameters with minimal side effects. Conclusion: The results from this study demonstrate the potential use of SiPore15 as a treatment for prediabetes that may also delay or prevent the onset of Type 2 diabetes.

Association Between Lipid Accumulation Product and Target Organ Damage in Elderly Population: The Northern Shanghai Study

Introduction

Lipid accumulation product (LAP), calculated from waist circumference (WC) and triglycerides (TG), is a novel index that correlates cardiovascular disease. We aimed to investigate the relationship between LAP and target organ damage (TOD) in elderly Chinese community-dwelling individuals.

Materials and Methods

We enrolled 3363 participants whose age was ≥65 years old. TOD, including left ventricular hypertrophy (LVH), arterial stiffness (AS), lower extremity atherosclerotic (LEA), micro-albuminuria (MAU) and chronic kidney disease (CKD), was measured using standard methods. LAP was calculated as (WC–65) × TG in men and (WC–58) × TG in women. Both quartiles and continuation of LAP were analyzed.

Results

Age-sex adjusted partial correlation analysis showed that LAP was significantly associated with CVD risk factors. With the first quartile (Q1) as a reference, in univariate logistic regression, the fourth quartile (Q4) of LAP was associated with all TOD. In multivariate model, Q4 of LAP was only associated with an increased risk of AS (odds ratio (OR) = 1.88, 95% confidence interval (CI): 1.37–2.58, P_{for trend}< 0.001), MAU (OR = 1.33, 95% CI: 1.01–1.75, P_{for trend}= 0.02) and CKD (OR = 2.39, 95% CI: 1.39–4.12, P_{for trend}< 0.001). But, Q4 of LAP was not associated with an increased risk of LVH (OR = 1.19, 95% CI: 0.85–1.65, P_{for trend}= 0.25) or LEA (OR = 0.87, 95% CI: 0.58–1.29, P_{for trend}= 0.96). Similar associations were found when analyzed continuously.

Conclusion

The novel metabolic parameter LAP is significantly and independently associated with an increased risk of arterial stiffness, chronic kidney disease and micro-albuminuria in Chinese community-dwelling elderly individuals.

Neck Circumference and Cerebral Gray Matter Volume

BACKGROUND

While obesity is linked with brain atrophy and dementia incidence, associations with regional adiposity are uncertain. Our goal was to determine whether cerebral gray matter volume is related to neck circumference (NC), a measure of regional adiposity having unique relationships with metabolic disorders and cardiovascular disease.

METHODS

Magnetic resonance imaging and NC were cross-sectionally assessed from 2011 to 2014 in a population-based sample of 2916 men and women in the Korean Genome and Epidemiology Study.

RESULTS

For men, NC was inversely associated with total and regional gray matter in the frontal, temporal, and occipital lobes after adjusting for age and intracranial brain volume. Associations were especially strong in the presence of diabetes. With further adjustment for indices of body composition and other characteristics, total and frontal gray matter in diabetic men were lowered by 6.1 mL (95% confidence interval: 2.5-9.7, P=0.004) and 2.9 mL (95% confidence interval: 1.0-4.9, P=0.017), respectively, per SD increase in NC (2.3 cm). For men without diabetes, and in all women, associations were less apparent.

CONCLUSIONS

In men with diabetes, NC was inversely associated with cerebral gray matter volume. The link between neck anthropometry and brain aging in diabetic men warrants further consideration.

Serum levels of adiponectin, resistin and tumour necrosis factor-alpha in Nigerian men with nuchal fat fold

BACKGROUND

Factors necessitating the propensity of adults with upper body fat deposition (UBFD) for developing insulin resistance and cardiovascular diseases (CVDs) are poorly understood. Therefore, understanding the roles of adipocytokines in the development of UBFD-associated pathologies could be of clinical importance.

AIM

To assess the levels of selected adipocytokines in males with nuchal fat fold (NFF).

METHODOLOGY

Eighty-six males (43 with NFF and 43 without NFF) were enrolled into this study. Serum levels of tumour necrosis factor-alpha (TNF-α), resistin and adiponectin were determined using ELISA.

RESULTS

Adiponectin level was significantly higher while resistin and TNF-α levels were significantly lower in NFF compared with the controls. TNF-α had significant positive correlation with systolic blood pressure (SBP) while adiponectin had significant positive correlation with the waist-hip ratio (WHR). Stratifying based on the obesity status, the mean body weight, BMI, waist circumference (WC), hip circumference (HC), WHR, neck circumference (NC), NFF and diastolic BP were significantly higher in NFF with obesity compared with those without obesity. However, levels of TNF-α, resistin and adiponectin were similar between the two groups.

CONCLUSIONS

NFF is associated with elevation in adiponectin level and increased CVD risk. NFF can therefore, serve as an index of early onset of cardiometabolic diseases.

High prevalence of steroid-induced glucose intolerance with normal fasting glycaemia during low-dose glucocorticoid therapy: an oral glucose tolerance test screening study

OBJECTIVES

To evaluate the prevalence and risk factors of new-onset glucose metabolism impairment using an oral glucose tolerance test (OGTT) in patients with normal fasting glycaemia on long-term glucocorticoid (GC) treatment.

METHODS

An OGTT was performed in 150 patients without a previous history of pre-diabetes or diabetes who were diagnosed with inflammatory rheumatic diseases and treated with GCs >3 months. All participants underwent clinical and biochemical evaluation for risk factors of diabetes: age, sex, current and cumulative dose of steroids, treatment duration, waist circumference, BMI, Homeostatic Model Assessment for Insulin Resistance, fasting insulin concentration, family history of diabetes, CRP, 28-joint DAS with CRP, type of connective tissue disease and trunk fat percentage measured by DXA. Logistic regression analysis was conducted to evaluate the association between the presence of impaired glucose tolerance (IGT) in the OGTT and analysed risk factors.

RESULTS

A total of 102 patients (68%) had fully normal glucose tolerance. Diabetes, isolated impaired fasting glucose, isolated IGT and combined impaired fasting glucose + IGT was diagnosed in 3.3, 4.67, 19.33 and 4.67% of patients, respectively; 20% of participants had IGT or diabetes despite normal fasting glucose concentration. The median cumulative dose and current dose (5 mg) of GCs and treatment duration were similar compared with the normal glucose tolerance group. In a multivariate logistic regression model, only older age (particularly ≥50 years of age) and trunk fat percentage remained significant factors predicting IGT or diabetes in the OGTT.

CONCLUSION

New-onset GC-induced glucose intolerance, even in patients on long-term low-dose treatment, is prevalent despite normal fasting glucose concentration and patients should be screened with an OGTT despite the absence of classic risk factors of diabetes.

White adipose tissue dysfunction in obesity and aging

Both obesity and aging are associated with the development of metabolic diseases such as type 2 diabetes and cardiovascular disease. Chronic low-grade inflammation of adipose tissue is one of the mechanisms implicated in the progression of these diseases. Obesity and aging trigger adipose tissue alterations that ultimately lead to a pro-inflammatory phenotype of the adipose tissue-resident immune cells. Obesity and aging also share other features such as a higher visceral vs. subcutaneous adipose tissue ratio and a decreased lifespan. Here, we review the common characteristics of obesity and aging and the alterations in white adipose tissue and resident immune cells. We focus on the adipose tissue metabolic derangements in obesity and aging such as inflammation and adipose tissue remodeling.

Higher Leptin-to-Adiponectin Ratio Strengthens the Association Between Body Measurements and Occurrence of Type 2 Diabetes Mellitus

Aim: This case-control study aimed to investigate the interrelations of body measurements and selected biomarkers in type 2 diabetes mellitus (T2DM). Methods: We recruited 98 patients with T2DM and 98 controls from 2016 to 2018 in Taiwan. Body measurements were obtained using a three-dimensional body surface scanning system. Four biomarkers related to insulin resistance, adipokines, and inflammation were assayed. A multiple logistic regression model was used to perform multivariable analyses. Results: Four body measurements, namely waist circumference (odds ratio, OR = 1.073; 95% confidence interval, CI = 1.017-1.133), forearm circumference (OR = 1.227; 95% CI = 1.002-1.501), thigh circumference (OR = 0.841; 95% CI = 0.73-0.969), and calf circumference (OR = 1.25; 95% CI = 1.076-1.451), were significantly associated with T2DM. Leptin (OR = 1.09; 95% CI = 1.036-1.146) and adiponectin (OR = 0.982; 95% CI = 0.967-0.997) were significantly associated with T2DM. Six body measurement combinations, namely body mass index, waist-to-hip ratio, waist-to-height ratio, waist-to-thigh ratio, forearm-to-thigh ratio, and calf-to-thigh ratio (CTR), were significantly associated with T2DM. CTR had the strongest linear association with T2DM. Moderating effects of significant biomarkers, namely leptin and adiponectin, were observed. Participants with high leptin-to-adiponectin ratios and in the fourth CTR quartile were 162.2 times more prone to develop T2DM. Conclusions: We concluded that a combination of leptin and adiponectin modulated the strength of the association between body measurements and T2DM while providing clues for high-risk group identification and mechanistic conjectures of preventing T2DM.

Heritability of fat distributions in male mice from the founder strains of the Diversity Outbred mouse population

Specific fat distributions are risk factors for complex diseases, including coronary heart disease and obstructive sleep apnea. To demonstrate the utility of high-diversity mouse models for elucidating genetic associations, we describe the phenotyping and heritability of fat distributions within the five classical inbred and three wild-derived founder mouse strains of the Collaborative Cross and Diversity Outbred mice. Measurements of subcutaneous and internal fat volumes in the abdomen, thorax and neck, and fat volumes in the tongue and pericardium were obtained using magnetic resonance imaging in male mice from the A/J (n = 12), C57BL/6J (n = 17), 129S1/SvlmJ (n = 12), NOD/LtJ (n = 14), NZO/HILtJ (n = 12), CAST/EiJ (n = 14), PWK/PhJ (n = 12), and WSB/EiJ (n = 15) strains. Phenotypes were compared across strains using analysis of variance and heritability estimated as the proportion of phenotypic variability attributable to strain. Heritability ranged from 44 to 91% across traits, including >70% heritability of tongue fat. A majority of heritability estimates remained significant controlling for body weight, suggesting genetic influences independent of general obesity. Principal components analysis supports genetic influences on overall obesity and specific to increased pericardial and intra-neck fat. Thus, among the founder strains of the Collaborative Cross and Diversity Outbred mice, we observed significant heritability of subcutaneous and internal fat volumes in the neck, thorax and abdomen, pericardial fat volume and tongue fat volume, consistent with genetic architecture playing an important role in explaining trait variability. Findings pave the way for studies utilizing high-diversity mouse models to identify genes affecting fat distributions and, in turn, influencing risk for associated complex disorders.

Retinol-binding protein 4 in obesity and metabolic dysfunctions

Excessive increased adipose tissue mass in obesity is associated with numerous co-morbid disorders including increased risk of type 2 diabetes, fatty liver disease, hypertension, dyslipidemia, cardiovascular diseases, dementia, airway disease and some cancers. The causal mechanisms explaining these associations are not fully understood. Adipose tissue is an active endocrine organ that secretes many adipokines, cytokines and releases metabolites. These biomolecules referred to as adipocytokines play a significant role in the regulation of whole-body energy homeostasis and metabolism by influencing and altering target tissues function. Understanding the mechanisms of adipocytokine actions represents a hot topic in obesity research. Among several secreted bioactive signalling molecules from adipose tissue and liver, retinol-binding protein 4 (RBP4) has been associated with systemic insulin resistance, dyslipidemia, type 2 diabetes and other metabolic diseases. Here, we aim to review and discuss the current knowledge on RBP4 with a focus on its role in the pathogenesis of obesity comorbid diseases.

Interaction of genetic and environmental factors for body fat mass control: observational study for lifestyle modification and genotyping

Previous studies suggested that genetic, environmental factors and their interactions could affect body fat mass (BFM). However, studies describing these effects were performed at a single time point in a population. In this study, we investigated the interaction between genetic and environmental factors in affecting BFM and implicate the healthcare utilization of lifestyle modifications from a personalized and genomic perspective. We examined how nutritional intake or physical activity changes in the individuals affect BFM concerning the genetic composition. We conducted an observational study including 259 adult participants with single nucleotide polymorphism (SNP) genotyping and longitudinal lifestyle monitoring, including food consumption and physical activities, by following lifestyle modification guidance. The participants’ lifelog data on exercise and diet were collected through a wearable device for 3 months. Moreover, we measured anthropometric and serologic markers to monitor their potential changes through lifestyle modification. We examined the influence of genetic composition on body fat reduction induced by lifestyle changes using genetic risk scores (GRSs) of three phenotypes: GRS-carbohydrate (GRS-C), GRS-fat (GRS-F), and GRS-exercise (GRS-E). Our results showed that lifestyle modifications affected BFM more significantly in the high GRS class compared to the low GRS class, indicating the role of genetic factors affecting the efficiency of the lifestyle modification-induced BFM changes. Interestingly, the influence of exercise modification in the low GRS class with active lifestyle change was lower than that in the high GRS class with inactive lifestyle change (P = 0.022), suggesting the implication of genetic factors for efficient body fat control.

Circulating Adiponectin and Resistin Levels Are Associated with Adiposity Indices and Physical Fitness in Healthy Adult Males

BACKGROUND The aim of this study was to assess the correlation of physical fitness scores (PFS) with serum adiponectin, resistin, and adiponectin/resistin ratio (AR ratio) in relation to body adiposity indices in healthy adult males. MATERIAL AND METHODS This cross-sectional study was conducted at the Clinical Physiology Unit, Physiology Department, King Saud University Medical City, King Saud University, Riyadh, from March 2017 to April 2018. We included 125 healthy adult males. Serum samples were obtained after overnight fasting. Analysis was performed for fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), basal insulin, lipid profile, resistin, and adiponectin. Bioimpedance analysis (BIA) was used to assess body composition. Based on ideal body composition, PFS were computed as previously published for all subjects and compared with serum markers. RESULTS There was a positive correlation of adiponectin with PFS (r=.218, p=0.015) and an inverse correlation with obesity degree (OD), OD (r=-.239, p=0.001), body mass index (BMI) (r=-.244, p=0.001), and waist/hip ratio (WHR) WHR (r=-.296, p=0.001). Moreover, it was correlated negatively with basal insulin (r=-.211, p=0.009) and homeostatic insulin resistance model (HOMA-IR) HOMA-IR (r=-.221, p=0.013). Resistin was correlated negatively with PFS (r=-.203, p=0.023), while its correlation with OD, BMI, WHR, and HOMA-IR was not significant. AR ratio was positively correlated with PFS (r=.286, p=0.001) and negatively with OD (r=-.210, p=0.019), BMI (r=-.222, p=0.013), WHR (r=-.308, p=0.001) and basal insulin (r=-.237, p=0.008). In linear regression analysis, the relationship of PFS was significant with adiponectin (r=.218, p=0.015), resistin (r=-.203, p=0.023) and AR ratio (r=.286, p=0.001). ROC curve analysis showed that individually the values of adiponectin and resistin were not significantly correlated with PFS, but they were significant with the combined AR ratio with AUC 64.6% (p=0.029). CONCLUSIONS Serum adiponectin was positively correlated and resistin was negatively correlated with physical fitness scores based on healthy body composition with low proportion of body adiposity and a higher proportion of fat-free mass. However, the combined effect of adiponectin/resistin ratio is an even better predictor of physical fitness. Moreover, the adiponectin/resistin ratio is even more highly associated with physical fitness than adiponectin or resistin alone.

Aging mitigates the severity of obesity-associated metabolic sequelae in a gender independent manner

BACKGROUND

Understanding gender-associated bias in aging and obesity-driven metabolic derangements has been hindered by the inability to model severe obesity in female mice.

METHODS

Here, using chow- or high fat diet (HFD)-feeding regimens at standard (TS) and thermoneutral (TN) housing temperatures, the latter to model obesity in female mice, we examined the impact of gender and aging on obesity-associated metabolic derangements and immune responsiveness. Analysis included quantification of: (i) weight gain and adiposity; (ii) the development and severity of glucose dysmetabolism and non-alcoholic fatty liver disease (NAFLD); and (iii) induction of inflammatory pathways related to metabolic dysfunction.

RESULTS

We show that under chow diet feeding regimen, aging was accompanied by increased body weight and white adipose tissue (WAT) expansion in a gender independent manner. HFD feeding regimen in aged, compared to young, male mice at TS, resulted in attenuated glucose dysmetabolism and hepatic steatosis. However, under TS housing conditions only aged, but not young, HFD fed female mice developed obesity. At TN however, both young and aged HFD fed female mice developed severe obesity. Independent of gender or housing conditions, aging attenuated the severity of metabolic derangements in HFD-fed obese mice. Tempered severity of metabolic derangements in aged mice was associated with increased splenic frequency of regulatory T (Treg) cells, Type I regulatory (Tr1)-like cells and circulating IL-10 levels and decreased vigor of HFD-driven induction of inflammatory pathways in adipose and liver tissues.

CONCLUSION

Our findings suggest that aging-associated altered immunological profile and inflammatory vigor may play a dominant role in the attenuation of obesogenic diet-driven metabolic dysfunction.

How the love of muscle can break a heart: Impact of anabolic androgenic steroids on skeletal muscle hypertrophy, metabolic and cardiovascular health

It is estimated 6.4% of males and 1.6% of females globally use anabolic-androgenic steroids (AAS), mostly for appearance and performance enhancing reasons. In combination with resistance exercise, AAS use increases muscle protein synthesis resulting in skeletal muscle hypertrophy and increased performance. Primarily through binding to the androgen receptor, AAS exert their hypertrophic effects via genomic, non-genomic and anti-catabolic mechanisms. However, chronic AAS use also has a detrimental effect on metabolism ultimately increasing the risk of cardiovascular disease (CVD). Much research has focused on AAS effects on blood lipids and lipoproteins, with abnormal concentrations of these associated with insulin resistance, hypertension and increased visceral adipose tissue (VAT). This clustering of interconnected abnormalities is often referred as metabolic syndrome (MetS). Therefore, the aim of this review is to explore the impact of AAS use on mechanisms of muscle hypertrophy and markers of MetS. AAS use markedly decreases high-density lipoprotein cholesterol (HDL-C) and increases low-density lipoprotein cholesterol (LDL-C). Chronic AAS use also appears to cause higher fasting insulin levels and impaired glucose tolerance and possibly higher levels of VAT; however, research is currently lacking on the effects of AAS use on glucose metabolism. While cessation of AAS use can restore normal lipid levels, it may lead to withdrawal symptoms such as depression and hypogonadism that can increase CVD risk. Research is currently lacking on effective treatments for withdrawal symptoms and further long-term research is warranted on the effects of AAS use on metabolic health in males and females.

The Association of Upper Body Obesity with Insulin Resistance in the Newfoundland Population

Body-fat distribution is a primary risk factor for insulin resistance and cardiovascular disease. Visceral fat explains only a portion of this risk. The link between upper-body fat and insulin resistance is uncertain. Furthermore, upper-body fat is not clearly defined. Dual-energy X-ray absorptiometry (DXA) can accurately quantify body fat. In this study, we explored the relationship between non-visceral upper-body adiposity and insulin resistance and other markers of metabolic syndrome. Fat proportions in the upper body, leg, and visceral regions were quantified by using DXA in 2547 adult Newfoundlanders aged 19 and older. Adjusting for remaining fat regions, we performed partial correlation analysis for each body region and insulin resistance defined by the Homeostatic Model of Assessment (HOMA). Similarly, partial correlation analysis was also performed between each fat region and other markers of metabolic syndrome, including high-density lipoprotein cholesterol (HDL), triglycerides (TG), body mass index (BMI), and blood pressure. Major confounding factors, including age, caloric intake, and physical activity, were statistically controlled by using partial correlation analysis. Interactions between sex, menopausal status, and medication status were also tested. Arm adiposity was correlated with HOMA-IR (R = 0.132, p < 0.001) and HOMA-β (R = 0.134, p < 0.001). Visceral adiposity was correlated with HOMA-IR (R = 0.230, p < 0.001) and HOMA-β (R = 0.160, p < 0.001). No significant correlation between non-visceral trunk adiposity and insulin resistance was found. Non-visceral trunk adiposity was negatively correlated with HDL in men (R = −0.110, p < 0.001) and women (R = −0.117, p < 0.001). Non-visceral trunk adiposity was correlated with TG (total: R = 0.079, p < 0.001; men: R = 0.105, p = 0.012; women: R = 0.078, p = 0.001). In menopausal women, leg adiposity was negatively correlated with HOMA-IR (R = −0.196, p < 0.001) and HOMA-β (R = −0.101, p = 0.012). Upper-body adiposity in the arms is an independent contributor to insulin resistance. Upper-body adiposity in the non-visceral trunk region is an independent contributor to metabolic syndrome. Leg adiposity is protective against metabolic syndrome in women.

The Tri-ponderal Mass Index is associated with adiposity in adolescent type 2 diabetes mellitus: a cross-sectional analysis

Pediatric type 2 diabetes mellitus (T2DM) patients are often overweight or obese, yet there are no validated clinical measures of adiposity to stratify cardiometabolic risk in this population. The tri-ponderal mass index (TMI, kg/m³) has recently been reported as a measure of adiposity in children, but there has been no validation of the association of TMI with adiposity in pediatric T2DM. We hypothesized that in children with T2DM, the TMI can serve as a more accurate measure of adiposity when compared to BMI z-score, and that it is associated with components of the metabolic syndrome. This is a cross-sectional secondary data analysis from the Improving Renal Complications in Adolescents with Type 2 Diabetes Through REsearch (iCARE) study (n = 116, age 10.20–17.90 years). Spearman’s correlations and multivariable regression were used in the analyses. When compared to DXA, TMI demonstrated significant correlation with total adiposity versus BMI z-score (TMI r = 0.74, p-value < 0.0001; BMI z-score r = − 0.08, p-value 0.403). In regression analyses, TMI was associated with WHtR (B = 35.54, 95% CI 28.81, 42.27, p-value < 0.0001), MAP dipping (B = 1.73, 95% CI 0.12, 3.33, p-value = 0.035), and HDL (B = − 5.83, 95% CI − 10.13, − 1.54, p-value = 0.008). In conclusion, TMI is associated with adiposity and components of the metabolic syndrome in pediatric T2DM patients.

Contribution of Adipose Tissue Oxidative Stress to Obesity-Associated Diabetes Risk and Ethnic Differences: Focus on Women of African Ancestry

Adipose tissue (AT) storage capacity is central in the maintenance of whole-body homeostasis, especially in obesity states. However, sustained nutrients overflow may dysregulate this function resulting in adipocytes hypertrophy, AT hypoxia, inflammation and oxidative stress. Systemic inflammation may also contribute to the disruption of AT redox equilibrium. AT and systemic oxidative stress have been involved in the development of obesity-associated insulin resistance (IR) and type 2 diabetes (T2D) through several mechanisms. Interestingly, fat accumulation, body fat distribution and the degree of how adiposity translates into cardio-metabolic diseases differ between ethnicities. Populations of African ancestry have a higher prevalence of obesity and higher T2D risk than populations of European ancestry, mainly driven by higher rates among African women. Considering the reported ethnic-specific differences in AT distribution and function and higher levels of systemic oxidative stress markers, oxidative stress is a potential contributor to the higher susceptibility for metabolic diseases in African women. This review summarizes existing evidence supporting this hypothesis while acknowledging a lack of data on AT oxidative stress in relation to IR in Africans, and the potential influence of other ethnicity-related modulators (e.g., genetic-environment interplay, socioeconomic factors) for consideration in future studies with different ethnicities.

Advances in Understanding of the Role of Lipid Metabolism in Aging

During aging, body adiposity increases with changes in the metabolism of lipids and their metabolite levels. Considering lipid metabolism, excess adiposity with increased lipotoxicity leads to various age-related diseases, including cardiovascular disease, cancer, arthritis, type 2 diabetes, and Alzheimer's disease. However, the multifaceted nature and complexities of lipid metabolism make it difficult to delineate its exact mechanism and role during aging. With advances in genetic engineering techniques, recent studies have demonstrated that changes in lipid metabolism are associated with aging and age-related diseases. Lipid accumulation and impaired fatty acid utilization in organs are associated with pathophysiological phenotypes of aging. Changes in adipokine levels contribute to aging by modulating changes in systemic metabolism and inflammation. Advances in lipidomic techniques have identified changes in lipid profiles that are associated with aging. Although it remains unclear how lipid metabolism is regulated during aging, or how lipid metabolites impact aging, evidence suggests a dynamic role for lipid metabolism and its metabolites as active participants of signaling pathways and regulators of gene expression. This review describes recent advances in our understanding of lipid metabolism in aging, including established findings and recent approaches.

Effect of genetic liability to visceral adiposity on stroke and its subtypes: A Mendelian randomization study

BACKGROUND

Observational studies have found an association between visceral adiposity and stroke.

AIMS

The purpose of this study was to investigate the role and genetic effect of visceral adipose tissue accumulation on stroke and its subtypes.

METHODS

In this two-sample Mendelian randomization study, genetic variants (221 single nucleotide polymorphisms; P < 5 × 10^-8) using as instrumental variables for Mendelian randomization analysis was obtained from a genome-wide association study of visceral adipose tissue. The outcome datasets for stroke and its subtypes were obtained from the MEGASTROKE consortium (up to 67,162 cases and 453,702 controls). Mendelian randomization standard analysis (inverse variance weighted method) was conducted to investigate the effect of genetic liability to visceral adiposity on stroke and its subtypes. Sensitivity analyses (Mendelian randomization-Egger, weighted median, Mendelian randomization-pleiotropy residual sum and outlier) were also utilized to assess horizontal pleiotropy and remove outliers. Multi-variable Mendelian randomization analysis was employed to adjust potential confounders.

RESULTS

In the standard Mendelian randomization analysis, genetically determined visceral adiposity (per 1 SD) was significantly associated with a higher risk of stroke (odds ratio (OR) 1.30; 95% confidence interval (CI) 1.21-1.41, P = 1.48× 10^-11), ischemic stroke (OR 1.30; 95% CI 1.20-1.41, P = 4.01 × 10^-10) and large artery stroke (OR 1.49; 95% CI 1.22-1.83, P = 1.16 × 10^-4). The significant association was also found in sensitivity analysis and multi-variable Mendelian randomization analysis.

CONCLUSIONS

Genetic liability to visceral adiposity was significantly associated with an increased risk of stroke, ischemic stroke, and large artery stroke. The effect of genetic susceptibility to visceral adiposity on the stroke warrants further investigation.

Body Composition Methods in Adults with Type 2 Diabetes or at Risk for T2D: a Clinical Review

PURPOSE OF REVIEW

The aim of this study is to summarize anthropometric and advanced methods used to assess body composition in adults diagnosed with type 2 diabetes (T2D) or at risk for T2D that provide clinically relevant information about T2D disease-related complications or risk factors.

RECENT FINDINGS

Anthropometry is commonly used in clinical settings; however, provides unreliable estimates of fat mass, fat-free mass, and body fat distribution for metabolic health assessments compared to advanced techniques such as bioelectrical impedance analysis (BIA), dual-energy x-ray absorptiometry (DXA), computerized tomography (CT), and magnetic resonance imaging (MRI). Few studies report the clinical use of anthropometric and advanced body composition methods that identify T2D disease-related complications or T2D risk factors. Anthropometry, BIA, DXA, CT, and MRI were used to estimate body adiposity and distribution, visceral and subcutaneous adipose tissue depots, and skeletal muscle mass. Review findings indicate that these methods were capable of identifying clinically relevant T2D disease-related complications such as sarcopenia and T2D risk factors such as obesity or regional adiposity. However, estimates were often sex and race/ethnicity specific warranting cross-validation of these methods in broader populations with T2D or risk for T2D prior to clinical implementation.

Adipose tissue and age‑dependent insulin resistance: New insights into WAT browning (Review)

Insulin resistance (IR) is defined as impaired insulin function, reduced glucose uptake and increased glucose production, which can result in type II diabetes, metabolic syndrome and even bone metabolic disorders. A possible reason for the increasing incidence of IR is population aging. Adipose tissue (AT) is an important endocrine organ that serves a crucial role in whole-body energy homeostasis. AT can be divided into white AT (WAT), beige AT and brown AT (BAT). Several mechanisms have been previously associated with age-dependent IR in WAT. However, BAT, a metabolically active tissue, controls the levels of plasma glucose and triglyceride metabolism. Therefore, the present review aimed to summarize the mechanisms of age-dependent IR induced by AT and to determine the role of WAT browning in achieving positive therapeutic outcomes in age-dependent IR.

Removal of Epididymal Visceral Adipose Tissue Prevents Obesity-Induced Multi-organ Insulin Resistance in Male Mice

Obesity is associated with insulin resistance, an important risk factor of type 2 diabetes, atherogenic dyslipidemia, and nonalcoholic fatty liver disease. The major purpose of this study was to test hypothesize that prophylactic removal of epididymal visceral adipose tissue (VAT) prevents obesity-induced multi-organ (liver, skeletal muscle, adipose tissue) insulin resistance. Accordingly, we surgically removed epididymal VAT pads from adult C57BL/6J mice and evaluated in vivo and cellular metabolic pathways involved in glucose and lipid metabolism following chronic high-fat diet (HFD) feeding. We found that VAT removal decreases HFD-induced body weight gain while increasing subcutaneous adipose tissue (SAT) mass. Strikingly, VAT removal prevents obesity-induced insulin resistance and hyperinsulinemia and markedly enhances insulin-stimulated AKT-phosphorylation at serine-473 (Ser473) and threonine-308 (Thr308) sites in SAT, liver, and skeletal muscle. VAT removal leads to decreases in plasma lipid concentrations and hepatic triglyceride (TG) content. In addition, VAT removal increases circulating adiponectin, a key insulin-sensitizing adipokine, whereas it decreases circulating interleukin 6, a pro-inflammatory adipokine. Consistent with these findings, VAT removal increases adenosine monophosphate-activated protein kinase C phosphorylation, a major downstream target of adiponectin signaling. Data obtained from RNA sequencing suggest that VAT removal prevents obesity-induced oxidative stress and inflammation in liver and SAT, respectively. Taken together, these findings highlight the metabolic benefits and possible action mechanisms of prophylactic VAT removal on obesity-induced insulin resistance and hepatosteatosis. Our results also provide important insight into understanding the extraordinary capability of adipose tissue to influence whole-body glucose and lipid metabolism as an active endocrine organ.

Adiposity and mortality in Korean adults: a population-based prospective cohort study

BACKGROUND

The Asia-Pacific obesity classification recommends using lower BMI cutoffs in Asians compared with those in Western populations. However, the supporting evidence is scarce and little is known about the exact shape of the relations between adiposity and mortality in Asians.

OBJECTIVES

We investigated the relations of BMI (in kg/m2), waist circumference, and predicted body fat mass with mortality using a population-based prospective cohort of Korean men and women.

METHODS

This analysis included 44,060 Korea National Health and Nutrition Examination Survey 2007-2014 participants who agreed to mortality follow-up through 31 December, 2016. At baseline, height, weight, and waist circumference were measured. Using DXA data, we derived predicted body fat and fat-free mass. Cox proportional hazards models were used to estimate HRs and 95% CIs for the associations with mortality, adjusting for potential confounders. We tested for nonlinearity using the likelihood ratio test comparing nonlinear restricted cubic spline models with linear models.

RESULTS

During ≤9.5 y of follow-up, 1682 deaths were identified. The relations of BMI with all-cause and cardiovascular mortality were J-shaped with the nadir at BMI = 25.0-29.9 (P-nonlinearity < 0.001). Among participants without a history of cancer or cardiovascular disease, waist circumference (≥95 compared with 75.0-79.9 cm: HR: 2.10; 95% CI: 1.54, 2.86) and predicted body fat mass (highest compared with lowest sextiles: 2.55; 95% CI: 1.60, 4.06) were positively associated with all-cause mortality (all P-nonlinearity ≤ 0.03), as well as cancer and cardiovascular mortality. The highest mortality was observed among participants who had both high predicted fat mass and low fat-free mass.

CONCLUSIONS

Our data suggest a strong positive association between adiposity and mortality in a population without pre-existing disease. We observed the lowest mortality at BMI = 25.0-29.9, suggesting that the current cutoff for overweight (BMI ≥23) may require re-evaluation and that BMI alone may not be a useful measure for indicating adiposity in Asians.

NDRG1 Activity in Fat Depots Is Associated With Type 2 Diabetes and Impaired Incretin Profile in Patients With Morbid Obesity

OBJECTIVE

We aimed to investigate insulin-, mTOR- and SGK1-dependent signaling basal states in morbidly obese patients' fat. We analyzed the correlation between the signaling activity, carbohydrate metabolism, and incretin profiles of patients.

METHODS

The omental and subcutaneous fat was obtained in patients with obesity. The omental study included 16 patients with normal glucose tolerance (NGT) and 17 patients with type 2 diabetes mellitus (T2DM); the subcutaneous study included 9 NGT patients and 12 T2DM patients. Insulin resistance was evaluated using the hyperinsulinemic euglycemic clamp test and HOMA-IR index. The oral glucose tolerance test (OGTT) for NGT patients and mixed meal tolerance test (MMTT) for T2DM patients were performed. The levels of incretins (GLP-1, GIP, oxyntomodulin) and glucagon were measured during the tests. Signaling was analyzed by Western blotting in adipose tissue biopsies.

RESULTS

We have shown equal levels of basal phosphorylation of insulin- and mTOR-dependent signaling in omental fat depot in NGT and T2DM obese patients. Nevertheless, pNDRG1-T346 was decreased in omental fat of T2DM patients. Correlation analysis has shown an inverse correlation of pNDRG1-T346 in omental fat and diabetic phenotype (HbA1c, impaired incretin profile (AUC GLP-1, glucagon)). Moreover, pNDRG1-T346 in subcutaneous fat correlated with impaired incretin levels among obese patients (inverse correlation with AUC glucagon and AUC GIP).

CONCLUSIONS

According to results of the present study, we hypothesize that phosphorylation of pNDRG1-T346 can be related to impairment in incretin hormone processing. pNDRG1-T346 in adipose tissue may serve as a marker of diabetes-associated impairments of the systemic incretin profile and insulin sensitivity.

The Postprandial Glycaemic and Hormonal Responses Following the Ingestion of a Novel, Ready-to-Drink Shot Containing a Low Dose of Whey Protein in Centrally Obese and Lean Adult Males: A Randomised Controlled Trial

PURPOSE

Elevated postprandial glycaemia [PPG] increases the risk of cardiometabolic complications in insulin-resistant, centrally obese individuals. Therefore, strategies that improve PPG are of importance for this population. Consuming large doses of whey protein [WP] before meals reduces PPG by delaying gastric emptying and stimulating the secretion of the incretin peptides, glucose-dependent insulinotropic polypeptide [GIP] and glucagon-like peptide 1 [GLP-1]. It is unclear if these effects are observed after smaller amounts of WP and what impact central adiposity has on these gastrointestinal processes.

METHODS

In a randomised-crossover design, 12 lean and 12 centrally obese adult males performed two 240 min mixed-meal tests, ~5-10 d apart. After an overnight fast, participants consumed a novel, ready-to-drink WP shot (15 g) or volume-matched water (100 ml; PLA) 10 min before a mixed-nutrient meal. Gastric emptying was estimated by oral acetaminophen absorbance. Interval blood samples were collected to measure glucose, insulin, GIP, GLP-1, and acetaminophen.

RESULTS

WP reduced PPG area under the curve [AUC_0-60] by 13 and 18.2% in the centrally obese and lean cohorts, respectively (both p <0.001). In both groups, the reduction in PPG was accompanied by a two-three-fold increase in GLP-1 and delayed gastric emptying. Despite similar GLP-1 responses during PLA, GLP-1 secretion during the WP trial was ~27% lower in centrally obese individuals compared to lean (p = 0.001). In lean participants, WP increased the GLP-1_ACTIVE/TOTAL ratio comparative to PLA (p = 0.004), indicative of reduced GLP-1 degradation. Conversely, no treatment effects for GLP-1_ACTIVE/TOTAL were seen in obese subjects.

CONCLUSION

Pre-meal ingestion of a novel, ready-to-drink WP shot containing just 15 g of dietary protein reduced PPG in lean and centrally obese males. However, an attenuated GLP-1 response to mealtime WP and increased incretin degradation might impact the efficacy of nutritional strategies utilising the actions of GLP-1 to regulate PPG in centrally obese populations. Whether these defects are caused by an individual's insulin resistance, their obese state, or other obesity-related ailments needs further investigation.

CLINICAL TRIAL REGISTRATION

ISRCTN.com, identifier [ISRCTN95281775]. https://www.isrctn.com/.

Aerobic Physical Exercise Improves Exercise Tolerance and Fasting Glycemia Independent of Body Weight Change in Obese Females

Obesity is associated with increased risk of several chronic diseases and the loss of disease-free years, which has increased the focus of much research for the discovery of therapy to combat it. Under healthy conditions, women tend to store more fat in subcutaneous deposits. However, this sexual dimorphism tends to be lost in the presence of comorbidities, such as type 2 diabetes mellitus (T2DM). Aerobic physical exercise (APE) has been applied in the management of obesity, however, is still necessary to better understand the effects of APE in obese female. Thus, we investigated the effect of APE on body weight, adiposity, exercise tolerance and glucose metabolism in female ob/ob mice. Eight-weeks-old female wild-type C57BL/6J and leptin-deficient ob/ob mice (Lep^ob) were distributed into three groups: wild-type sedentary group (Wt; n = 6), leptin-deficient sedentary group (Lep^obS; n = 5) and leptin-deficient trained group (Lep^obT; n = 8). The Lep^obT mice were subjected to 8 weeks of aerobic physical exercise (APE) at 60% of the maximum velocity achieved in the running capacity test. The APE had no effect in attenuating body weight gain, and did not reduce subcutaneous and retroperitoneal white adipose tissue (SC-WAT and RP-WAT, respectively) and interscapular brown adipose tissue (iBAT) weights. The APE neither improved glucose intolerance nor insulin resistance in the Lep^obT group. Also, the APE did not reduce the diameter or the area of RP-WAT adipocytes, but the APE reduced the diameter and the area of SC-WAT adipocytes, which was associated with lower fasting glycemia and islet/pancreas area ratio in the Lep^obT group. In addition, the APE increased exercise tolerance and this response was also associated with lower fasting glycemia in the Lep^obT group. In conclusion, starting APE at a later age with a more severe degree of obesity did not attenuate the excessive body weight gain, however the APE promoted benefits that can improve the female health, and for this reason it should be recommended as a non-pharmacological therapy for obesity.

Role of exercise on insulin sensitivity and beta-cell function: is exercise sufficient for the prevention of youth-onset type 2 diabetes?

Parallel with the current pediatric obesity epidemic, the escalating rates of youthonset type 2 diabetes mellitus (T2DM) have become a major public health burden. Although lifestyle modification can be the first-line prevention for T2DM in youths, there is a lack of evidence to establish optimal specific exercise strategies for obese youths at high risk for T2DM. The purpose of this narrative review is to summarize the potential impact of exercise on 2 key pathophysiological risk factors for T2DM, insulin sensitivity and β-cell function, among obese youths. The studies cited are grouped by use of metabolic tests, i.e., direct and indirect measures of insulin sensitivity and β-cell function. In general, there are an increasing number of studies that demonstrate positive effects of aerobic exercise, resistance exercise, and the 2 combined on insulin sensitivity. However, a lack of evidence exists for the effect of any exercise modality on β-cell functional improvement. We also suggest a future direction for research into exercise medical prevention of youth-onset T2DM. These suggestions focus on the effects of exercise modalities on emerging biomarkers of T2DM risk.

Good, better, best: clinical scenarios for the use of L-methylfolate in patients with MDD

Depression is among the most prevalent mental disorders worldwide, and a substantial proportion of patients do not respond adequately to standard antidepressants. Our understanding of the pathophysiology of depression is no longer limited to the chemical imbalance of neurotransmitters, but also involves the interplay of proinflammatory modulators in the central nervous system, as well as folate metabolism. Additional factors such as stress and metabolic disorders also may contribute. Multiple inflammatory, metabolic, and genetic markers have been identified and may provide critical information to help clinicians individualize treatments for patients to achieve optimal outcomes. Recent advancements in research have clarified underlying causes of depression and have led to possible new avenues for adjunctive treatment. Among these is L-methylfolate, a medical food that is thought to enhance synthesis of monoamines (serotonin, norepinephrine, and dopamine), suppress inflammation, and promote neural health. Clinical studies that assessed supplemental use of L-methylfolate in patients with usual care-resistant depression found that it resulted in improved outcomes. Patients with selective serotonin reuptake inhibitor-resistant depression, and particularly subgroups with biomarkers of inflammation or metabolic disorders or folate metabolism-related genetic polymorphisms (or ≥2 of these factors), had the best responses. Considering this, the goals of this review are to 1) highlight recent advances in the pathophysiology of major depressive disorder as it pertains to folate and associated biomarkers and 2) establish the profiles of patients with depression who could benefit most from supplemental use of L-methylfolate.

Cardiovascular Benefits and Lipid Profile Changes 5 Years After Bariatric Surgery: A Comparative Study Between Sleeve Gastrectomy and Roux-en-Y Gastric Bypass

INTRODUCTION

Visceral adipose tissue has been linked with cardiovascular events. Visceral adiposity index (VAI) is a routinely applicable tool for evaluation of visceral adipose dysfunction and linked to 10 year-cardiovascular risk. No previous studies have evaluated the changes over time of the VAI in patients who underwent different types of bariatric surgery.

MATERIALS AND METHODS

We reviewed data of 42 patients who underwent laparoscopic sleeve gastrectomy (LSG) and 61 patients who underwent laparoscopic Roux-en-Y gastric bypass (LRYGB). VAI, lipid profile, and several anthropometric variables were measured before and after 5 years following surgery.

RESULTS

During the studied time period, the BMI was similar between LSG and LRYGB patients (34.1 vs 31.6; p = 0.191), but the percentage of total weight loss (%TWL) for LRYGB was significantly higher than LSG (31.3% vs 23.0%; p < 0.001). LRYGB patients had a significant improvement of all lipid parameters evaluated over time, while LSG patients experienced only a reduction in triglycerides (TG) levels and an increase in HDL cholesterol (HDL-C). VAI values were similar in the two groups at baseline as well at the last follow-up point (5-year VAI, LSG: 0.93, RYGB: 0.93; p = 0.951). At multivariate regression analysis, 5-year-%TWL was the only independent predictor of a greater amount of VAI reduction over time.

CONCLUSION

Bariatric surgery, independent of the type of surgical procedure, decreases the cardiovascular disease (CVD) risks due to weight loss and improvement of lipid parameters. VAI could be a useful tool to better identify eligible patients for bariatric surgery and to determine the success of surgery.

The utility of visceral fat level measured by bioelectrical impedance analysis in predicting metabolic syndrome

BACKGROUND

Visceral adipose tissue dysfunction contributes to metabolic syndrome (MetS) and cardiovascular diseases. This study aims to investigate the association between visceral fat level measured by bioelectric impedance analysis (BIA) and MetS.

MATERIAL AND METHODS

This cross-sectional study recruited Taiwanese volunteers aged ≥20 years between 2012 and 2014. Anthropometric measurements and plasma concentrations of glucose, insulin, and lipid profiles were collected after at least 8 h of fasting. Insulin resistance was calculated by the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). Visceral fat level (VFL, ranges: 1-59) and trunk fat percentage were measured through by the Body Composition Analyzer TANITA AB 140 Viscan.

RESULTS

A total of 1086 volunteers (mean age = 44.2 ± 13.2 years) were enrolled. Multiple regression analyses showed that triglycerides levels and blood pressure increased while high-density lipoprotein-cholesterol decreased with VFL in both genders (p < 0.05). Increased HOMA-IR and VFL had a synergistic effect on MetS. Higher VFL was independently associated with MetS in both men (OR = 1.33, 95% CI: 1.19-1.48) and women (OR = 1.28, 95% CI: 1.17-1.39).

CONCLUSIONS

Higher VFL is associated with MetS and its components. The portable BIA machine is easily applicable and useful tool to measure visceral fat in the community setting.

Ethnic and Adipose Depot Specific Associations Between DNA Methylation and Metabolic Risk

Background

Metabolic risk varies according to body mass index (BMI), body fat distribution and ethnicity. In recent years, epigenetics, which reflect gene-environment interactions have attracted considerable interest as mechanisms that may mediate differences in metabolic risk. The aim of this study was to investigate DNA methylation differences in abdominal and gluteal subcutaneous adipose tissues of normal-weight and obese black and white South African women.

Methods

Body composition was assessed using dual-energy x-ray absorptiometry and computerized tomography, and insulin sensitivity was measured using a frequently sampled intravenous glucose tolerance test in 54 normal-weight (BMI 18–25 kg/m²) and obese (BMI ≥ 30 kg/m²) women. Global and insulin receptor (INSR) DNA methylation was quantified in abdominal (ASAT) and gluteal (GSAT) subcutaneous adipose depots, using the Imprint methylation enzyme-linked immunosorbent assay and pyrosequencing. INSR gene expression was measured using quantitative real-time PCR.

Results

Global DNA methylation in GSAT varied according to BMI and ethnicity, with higher levels observed in normal-weight white compared to normal-weight black (p = 0.030) and obese white (p = 0.012) women. Pyrosequencing of 14 CpG sites within the INSR promoter also showed BMI, adipose depot and ethnic differences, although inter-individual variability prevented attainment of statistical significance. Both global and INSR methylation were correlated with body fat distribution, insulin resistance and systemic inflammation, which were dependent on ethnicity and the adipose depot. Adipose depot and ethnic differences in INSR gene expression were observed.

Conclusion

We show small, but significant global and INSR promoter DNA methylation differences in GSAT and ASAT of normal-weight and obese black and white South African women. DNA methylation in ASAT was associated with centralization of body fat in white women, whereas in black women DNA methylation in GSAT was associated with insulin resistance and systemic inflammation. Our findings suggest that GSAT rather than ASAT may be a determinant of metabolic risk in black women and provide novel evidence that altered DNA methylation within adipose depots may contribute to ethnic differences in body fat distribution and cardiometabolic risk.

Preoperative sarcopenia is associated with poor overall survival in pancreatic cancer patients following pancreaticoduodenectomy

OBJECTIVES

To analyze the effect of preoperative body composition on survival in patients with pancreatic cancer following pancreaticoduodenectomy (PD).

METHODS

Between October 2005 and August 2018, 116 patients (68 men, 48 women, mean age 66.2 ± 11.9 years) diagnosed with pancreatic adenocarcinoma following PD were retrospectively enrolled. The preoperative CT on vertebral level L3 was assessed for total abdominal muscle area (TAMA), visceral adipose tissue area (VAT), subcutaneous adipose tissue area (SAT), and mean skeletal muscle attenuation (SMD). The clinical data and pathological findings of tumors were collected. The impact of these factors on disease-free survival (DFS) and overall survival (OS) was evaluated by the Kaplan-Meier method and by univariable and multivariable Cox proportional hazards models.

RESULTS

The 3-year DFS and OS rates were 8% and 25%, respectively. Of 116 patients, 20 (17.2%), 3 (2.6%), and 46 (39.7%) patients were classified as having sarcopenia, sarcopenic obesity, and myosteatosis, respectively. The VAT-TAMA ratio (1.2 ± 0.7 vs 0.9 ± 0.5, p = 0.01) and the visceral to subcutaneous adipose tissue area ratio (1.3 ± 0.7 vs 0.9 ± 0.5, p = 0.04) were higher in sarcopenic patients than in the nonsarcopenic group. Preoperative sarcopenia and sarcopenic obesity were associated with shorter OS (p = 0.012 and p = 0.041, respectively), but not shorter DFS. Myosteatosis was neither associated with DFS nor OS. On multivariable analysis, sarcopenia was the only significant prognostic factor for OS (p = 0.039).

CONCLUSIONS

Preoperative sarcopenia assessed by CT is a poor prognostic factor for OS in pancreatic cancer patients after PD.

KEY POINTS

• Sarcopenia and sarcopenic obesity can be evaluated by abdominal CT on L3 level. • Patients with diabetes mellitus (DM) had lower sex-standardized subcutaneous adipose tissue area index and skeletal muscle density and higher visceral to subcutaneous adipose tissue area ratio than did those without DM. • Preoperative sarcopenia, sarcopenic obesity, and new-onset diabetes mellitus may predict poor overall survival in pancreatic cancer patients following pancreaticoduodenectomy.

Case of type 2 diabetes possibly caused by excessive accumulation of visceral fat in a child born small-for-gestational age

We encountered a 12-year-old boy with type 2 diabetes who was born small-for-gestational age. We described his clinical characteristics and a possible etiological factor for development of hyperglycemia. He developed well with sufficient nutrition and progressed to being overweight at 6 years-of-age as a result of a high-calorie, high-protein intake diet. He showed a diabetic pattern with a normal insulin response on an oral glucose tolerance test carried out with the urine glucose screening program at schools. He showed a large total fat area of 239.4 cm2 ; in particular, his visceral fat area was 103.0 cm2 with a high ratio of visceral fat area to subcutaneous fat area (0.76). The present case might show that insulin resistance, possibly as a result of accumulation of a great amount of visceral fat, might be attributed to the pathogenesis of type 2 diabetes in children born small-for-gestational age.

Role of Patatin-Like Phospholipase Domain-Containing 3 Gene for Hepatic Lipid Content and Insulin Resistance in Diabetes

OBJECTIVE

The rs738409(G) single nucleotide polymorphism (SNP) in the patatin-like phospholipase domain-containing 3 (PNPLA3) gene associates with increased risk and progression of nonalcoholic fatty liver disease (NAFLD). As the recently described severe insulin-resistant diabetes (SIRD) cluster specifically relates to NAFLD, this study examined whether this SNP differently associates with hepatic lipid content (hepatocellular lipids [HCL]) and insulin sensitivity in recent-onset diabetes.

RESEARCH DESIGN AND METHODS

A total of 917 participants in the German Diabetes Study (GDS) underwent genotyping, hyperinsulinemic-euglycemic clamps with stable isotopic tracer dilution, and MRS.

RESULTS

The G allele associated positively with HCL (β = 0.36, P < 0.01), independent of age, sex, and BMI across the whole cohort, but not in the individual clusters. Those with SIRD exhibited lowest whole-body insulin sensitivity compared with those with severe insulin-deficient (SIDD), moderate obesity-related (MOD), moderate age-related (MARD), and severe autoimmune diabetes (SAID) clusters (all P < 0.001). Interestingly, the SIRD group presented with higher prevalence of the rs738409(G) SNP compared with other clusters and the glucose-tolerant control group (P < 0.05). HCL was higher in the SIRD group (median 13.6% [1st quartile 5.8; 3rd quartile 19.1] compared with the MOD (6.4 % [2.1; 12.4], P < 0.05), MARD (3.0% [1.0; 7.9], P < 0.001), SAID (0.4% [0.0; 1.5], P < 0.001), and glucose-tolerant (0.9% [0.4; 4.9), P < 0.001) group. Although the PNPLA3 polymorphism did not directly associate with whole-body insulin sensitivity in SIRD, the G-allele carriers had higher circulating free fatty acid concentrations and greater adipose tissue insulin resistance compared with noncarriers (both P < 0.001).

CONCLUSIONS

Members of the SIRD cluster are more frequently carriers of the rs738409(G) variant. The SNP-associated adipose tissue insulin resistance and excessive lipolysis may contribute to their NAFLD.

Pathogenesis of type 2 diabetes risk in black Africans: a South African perspective

The prevalence of type 2 diabetes (T2D) is higher in black Africans than their European counterparts. This review summarizes the research exploring the pathogenesis of T2D in populations of African ancestry compared to white Europeans and shows that the pathogenesis differs by ethnicity. Black Africans present with a phenotype of low insulin sensitivity and hyperinsulinaemia as a result of increased insulin secretion and reduced hepatic insulin clearance. Whether hyperinsulinaemia precedes insulin resistance or is merely a compensatory mechanism is yet to be determined. Black Africans have lower visceral adipose tissue and ectopic fat deposition and greater peripheral (gluteo-femoral) fat deposition than their European counterparts. This suggests that black Africans are more sensitive to the effects of ectopic fat deposition, or alternatively, that ectopic fat is not an important mediator of T2D in black Africans. Importantly, ethnic disparities in T2D risk factors may be confounded by differences in sociocultural and lifestyle factors. Future longitudinal and dietary intervention studies, in combination with genetic analyses, are needed for a better understanding of the pathophysiology of T2D in black Africans. This will be key for effective prevention and management strategies.

Exercise training improves adipose tissue metabolism and vasculature regardless of baseline glucose tolerance and sex

INTRODUCTION

We investigated the effects of a supervised progressive sprint interval training (SIT) and moderate-intensity continuous training (MICT) on adipocyte morphology and adipose tissue metabolism and function; we also tested whether the responses were similar regardless of baseline glucose tolerance and sex.

RESEARCH DESIGN AND METHODS

26 insulin-resistant (IR) and 28 healthy participants were randomized into 2-week-long SIT (4-6×30 s at maximum effort) and MICT (40-60 min at 60% of maximal aerobic capacity (VO2peak)). Insulin-stimulated glucose uptake and fasting-free fatty acid uptake in visceral adipose tissue (VAT), abdominal and femoral subcutaneous adipose tissues (SATs) were quantified with positron emission tomography. Abdominal SAT biopsies were collected to determine adipocyte morphology, gene expression markers of lipolysis, glucose and lipid metabolism and inflammation.

RESULTS

Training increased glucose uptake in VAT (p<0.001) and femoral SAT (p<0.001) and decreased fatty acid uptake in VAT (p=0.01) irrespective of baseline glucose tolerance and sex. In IR participants, training increased adipose tissue vasculature and decreased CD36 and ANGPTL4 gene expression in abdominal SAT. SIT was superior in increasing VO2peak and VAT glucose uptake in the IR group, whereas MICT reduced VAT fatty acid uptake more than SIT.

CONCLUSIONS

Short-term training improves adipose tissue metabolism both in healthy and IR participants independently of the sex. Adipose tissue angiogenesis and gene expression was only significantly affected in IR participants.

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.

Extended Ketogenic Diet and Physical Training Intervention in Military Personnel

INTRODUCTION

Ketogenic diets (KDs) that elevate ketones into a range referred to as nutritional ketosis represent a possible nutrition approach to address the emerging physical readiness and obesity challenge in the military. An emerging body of evidence demonstrates broad-spectrum health benefits attributed to being in nutritional ketosis, but no studies have specifically explored the use of a KD in a military population using daily ketone monitoring to personalize the diet prescription.

MATERIALS AND METHODS

To evaluate the feasibility, metabolic, and performance responses of an extended duration KD, healthy adults (n = 29) from various military branches participated in a supervised 12-wk exercise training program. Fifteen participants self-selected to an ad libitum KD guided by daily measures of capillary blood ketones and 14 continued their normal mixed diet (MD). A battery of tests were performed before and after the intervention to assess changes in body mass, body composition, visceral fat, liver fat, insulin sensitivity, resting energy metabolism, and physical performance.

RESULTS

All KD subjects were in nutritional ketosis during the intervention as assessed by daily capillary beta-hydroxybutyrate (βHB) (mean βHB 1.2 mM reported 97% of all days) and showed higher rates of fat oxidation indicative of keto-adaptation. Despite no instruction regarding caloric intake, the KD group lost 7.7 kg body mass (range -3.5 to -13.6 kg), 5.1% whole-body percent fat (range -0.5 to -9.6%), 43.7% visceral fat (range 3.0 to -66.3%) (all p < 0.001), and had a 48% improvement in insulin sensitivity; there were no changes in the MD group. Adaptations in aerobic capacity, maximal strength, power, and military-specific obstacle course were similar between groups (p > 0.05).

CONCLUSIONS

US military personnel demonstrated high adherence to a KD and showed remarkable weight loss and improvements in body composition, including loss of visceral fat, without compromising physical performance adaptations to exercise training. Implementation of a KD represents a credible strategy to enhance overall health and readiness of military service members who could benefit from weight loss and improved body composition.

The association of the visceral adiposity index with insulin resistance and beta-cell function in Korean adults with and without type 2 diabetes mellitus

This study was conducted to assess the association of the visceral adiposity index (VAI) with insulin resistance and beta cell function in Korean adults with and without type 2 diabetes mellitus. The study was carried out using data from the 2015 Korean National Health and Nutrition Examination Survey (KNHANES VI-3) and included 4,922 adults, aged 20 or older. There were several key findings in the present study. First, in subjects without type 2 diabetes mellitus, homeostasis model assessment of insulin resistance (HOMA-IR) (p < 0.001) and beta cell function (HOMA-B) (p < 0.001), insulin (p < 0.001), fasting blood glucose (FBG) (p < 0.001), and metabolic syndrome (MetS) score (p < 0.001) were positively associated with quartiles of VAI. Second, in subjects with type 2 diabetes mellitus, HOMA-IR (p = 0.038), FBG (p = 0.007), and MetS score (p < 0.001) were positively associated with quartiles of VAI, but associations with HOMA-B (p = 0.879) and insulin (p = 0.104) were not significant. In conclusions, the visceral adiposity index is positively associated with insulin resistance and beta cell function in Korean adults without type 2 diabetes mellitus. The visceral adiposity index is positively associated with insulin resistance but not beta cell function in Korean adults with type 2 diabetes mellitus.