Ectopic Lipid Deposition Is Associated With Insulin Resistance in Postmenopausal Women

Effects of ambient air pollution on obesity and ectopic fat deposition: a protocol for a systematic review and meta-analysis

INTRODUCTION

Globally, the prevalence of obesity tripled from 1975 to 2016. There is evidence that air pollution may contribute to the obesity epidemic through an increase in oxidative stress and inflammation of adipose tissue. However, the impact of air pollution on body weight at a population level remains inconclusive. This systematic review and meta-analysis will estimate the association of ambient air pollution with obesity, distribution of ectopic adipose tissue, and the incidence and prevalence of non-alcoholic fatty liver disease among adults.

METHODS AND ANALYSIS

The study will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for conduct and reporting. The search will include the following databases: Ovid Medline, Embase, PubMed, Web of Science and Latin America and the Caribbean Literature on Health Sciences, and will be supplemented by a grey literature search. Each article will be independently screened by two reviewers, and relevant data will be extracted independently and in duplicate. Study-specific estimates of associations and their 95% Confidence Intervals will be pooled using a DerSimonian and Laird random-effects model, implemented using the RevMan software. The I2 statistic will be used to assess interstudy heterogeneity. The confidence in the body of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

ETHICS AND DISSEMINATION

As per institutional policy, ethical approval is not required for secondary data analysis. In addition to being published in a peer-reviewed journal and presented at conferences, the results of the meta-analysis will be shared with key stakeholders, health policymakers and healthcare professionals.

PROSPERO REGISTRATION NUMBER

CRD42023423955.

The Metabolic Syndrome, a Human Disease

This review focuses on the question of metabolic syndrome (MS) being a complex, but essentially monophyletic, galaxy of associated diseases/disorders, or just a syndrome of related but rather independent pathologies. The human nature of MS (its exceptionality in Nature and its close interdependence with human action and evolution) is presented and discussed. The text also describes the close interdependence of its components, with special emphasis on the description of their interrelations (including their syndromic development and recruitment), as well as their consequences upon energy handling and partition. The main theories on MS's origin and development are presented in relation to hepatic steatosis, type 2 diabetes, and obesity, but encompass most of the MS components described so far. The differential effects of sex and its biological consequences are considered under the light of human social needs and evolution, which are also directly related to MS epidemiology, severity, and relations with senescence. The triggering and maintenance factors of MS are discussed, with especial emphasis on inflammation, a complex process affecting different levels of organization and which is a critical element for MS development. Inflammation is also related to the operation of connective tissue (including the adipose organ) and the widely studied and acknowledged influence of diet. The role of diet composition, including the transcendence of the anaplerotic maintenance of the Krebs cycle from dietary amino acid supply (and its timing), is developed in the context of testosterone and β-estradiol control of the insulin-glycaemia hepatic core system of carbohydrate-triacylglycerol energy handling. The high probability of MS acting as a unique complex biological control system (essentially monophyletic) is presented, together with additional perspectives/considerations on the treatment of this 'very' human disease.

The effects of exercise training on body composition in postmenopausal women: a systematic review and meta-analysis

Introduction

We conducted a systematic review and meta-analysis to investigate the effect of exercise training on body composition outcomes in postmenopausal women.

Methods

PubMed, Web of Science, CINAHL, and Medline were searched to identify the randomized controlled trials which evaluated effect of exercise training versus control in postmenopausal women. Standardized mean differences (SMD), weighted mean differences (WMD) and 95% confidence intervals (95% CIs) were calculated using random effects model.

Results

One hundred and one studies involving 5,697 postmenopausal women were included in the meta-analysis. Results indicated that exercise training effectively increased muscle mass/ volume, muscle and fiber cross-sectional area and fat-free mass, and decreased fat mass, body fat percentage, waist circumference and visceral fat. Furthermore, subgroup analyses results revealed that aerobic and combined training had greater beneficial effects on fat mass outcomes, whereas resistance and combined training had greater beneficial effects on muscle mass outcomes.

Discussion

Overall, our results revealed that exercise training is effective for improving body composition in postmenopausal women. To be specific, aerobic training is effective on fat loss, whereas resistance training is effective on muscle gain. However, combination of aerobic and resistance trainings may be considered a viable strategy to improve body composition in postmenopausal women.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42021283425.

Effects of Exercise Intensity on Cardiometabolic Parameters of Ovariectomized Obese Mice

The aim of this study was to compare the effects of continuous-moderate vs. high-intensity interval aerobic training on cardiovascular and metabolic parameters in ovariectomized high-fat-fed mice. C57BL/6 female ovariectomized were divided into four groups (n=8): low-fat-fed sedentary (SLF); high-fat-fed sedentary (SHF); high-fat-fed moderate-intensity continuous trained (MICT-HF); and high-fat-fed high-intensity interval aerobic trained (HIIT-HF). The high-fat diet lasted 10 weeks. Ovariectomy was performed in the fourth week. The exercise training was carried out in the last four weeks of protocol. Fasting glycemia, oral glucose tolerance, arterial pressure, baroreflex sensitivity, and cardiovascular autonomic modulation were evaluated. Moderate-intensity continuous training prevented the increase in arterial pressure and promoted a reduction in HR at rest, associated with an improvement in the sympathovagal balance in MICT-HF vs. SHF. The high-intensity interval training reduced blood glucose and glucose intolerance in HIIT-HF vs. SHF and MICT-HF. In addition, it improved sympathovagal balance in HIIT-HF vs. SHF. Moderate-intensity continuous training was more effective in promoting cardiovascular benefits, while high-intensity interval training was more effective in promoting metabolic benefits.

Air pollution combined with high-fat feeding aggravates metabolic and cardiovascular diseases: A dangerous, oxidative, and immune-inflammatory association

Obesity and particulate air pollutant (PM_2.5) are important risk factors for cardiometabolic diseases. PM_2.5 exacerbates insulin resistance and lipid ectopic deposition in obese animals. The inorganic fraction of PM_2.5, the Residual Oil Fly Ash (ROFA), is related to cardiovascular events, by enhancing the generation of reactive species, inflammatory cytokines, and leukocyte activation. However, the synergistic effects of ROFA and a high-fat diet (HFD) are still poorly described, and the studies were mainly conducted with males.

AIMS

To investigate if ROFA could potentiate the cardiometabolic effects of diet-induced obesity in female rats.

MATERIAL AND METHODS

Wistar female rats were divided into four groups: Control (n = 6), Polluted (n = 6), HFD (n = 6), and HFD + Polluted (n = 6). HFD and HFD + Polluted received a high-fat diet (HFD) (58.3 % as fats), whilst Control and Polluted groups received a standard diet (Nuvilab CR-1). In addition, Polluted and HFD + Polluted groups received intranasal instillation of ROFA (250 μg/50 μL), while Control and HFD groups received saline solution (50 μL) daily, five days per week. Both interventions occurred 24 weeks after the animals were euthanized.

KEY FINDINGS

HFD combined with ROFA exposure impaired lipid profile challenged systemic and cardiac antioxidant defense, and presented a synergistic effect in inducing an immune-inflammatory condition. We found that the lipid profile disturbance is associated with HFD-induced hepatic, but not cardiac, deposition of triglycerides in female animals.

SIGNIFICANCE

Our results support the hypothesis that ROFA exposure combined with bad feeding can exacerbate metabolic and cardiovascular diseases.

The association of dietary insulin load and dietary insulin index with body composition among professional soccer players and referees

BACKGROUND

There has been limited research undertaken about the association of dietary insulin load (DIL) and dietary insulin index (DII) with body composition in non-athletic adults, however, to the best of our knowledge No previous study has investigated such an association in an athletic population.

PURPOSE

The aim of this study was to explore the association of DII and DIL with body compositions in male and female soccer players and referees.

METHODS

The cross-sectional study was conducted on 199 professional male and female soccer players and referees. A 147-item semi-quantitative food frequency questionnaire (FFQ) was adopted to congregate the participants' dietary data. Body composition was measured using InBody to gain a detailed understanding of fat mass, percent body fat (PBF), lean mass, percent muscle mass (PMM), and bone mineral content (BMC). Waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) were obtained from all participants. Other body composition parameters include a body shape index (ABSI), abdominal volume index (AVI), body adiposity index (BAI), body roundness index (BRI), conicity index (CI), weight-adjusted waist index (WWI) and waist-to-hip-to-height ratio (WHHR) were calculated using a particular defined formula.

RESULTS

Results of multiple linear regression revealed that there is a significant association between DIL and BMI (P = 0.04) in < 18 male soccer players, CI (P = 0.04) and WWI (P = 0.03) in ≥ 18 female soccer players, PBF (P = 0.02), PMM (P = 0.01) and WWI (P = 0.01) in ≥ 18 female soccer players. Nevertheless, no significant associations between DIL and body composition parameters were found in the referees. Additionally, there is a significant association between DII and BMC (P = 0.02) in male soccer referees, however, no significant associations were found in young soccer players and female athletes.

CONCLUSION

This study demonstrates that DIL is positively associated with BMI, CI, and WWI in male soccer players and PBF, and WWI in female soccer players. Although, there was an observed negative association between DIL and PMM in females. In addition, a significant negative association between DII and BMC was observed in male soccer players.

Canagliflozin ameliorates the development of NAFLD by preventing NLRP3-mediated pyroptosis through FGF21-ERK1/2 pathway

Recent studies have suggested that sodium-glucose co-transporter2 inhibitors go beyond their glycemic advantages to ameliorate the development of NAFLD. However, little research has been done on the underlying mechanisms. Here, we took deep insight into the effect of canagliflozin (CANA), one of the sodium-glucose co-transporter2 inhibitor, on the progression of NAFLD, and explored the molecular mechanisms. Our findings showed that CANA-treated ob/ob and diabetic mice developed improved glucose and insulin tolerance, although their body weights were comparable or even increased compared with the controls. The CANA treatment ameliorated hepatic steatosis and lipid accumulation of free fatty acid-treated AML12 cells, accompanied by decreased lipogenic gene expression and increased fatty acid β oxidation-related gene expression. Furthermore, inflammation and fibrosis genes decreased in the livers of CANA-treated ob/ob and diabetic mice mice. FGF21 and its downstream ERK1/2/AMPK signaling decreased, whereas NLRP3-mediated pyroptosis increased in the livers of the ob/ob and diabetic mice mice, which was reversed by the CANA treatment. In addition, blocking FGF21 or ERK1/2 activity antagonized the effects of CANA on NLRP3-mediated pyroptosis in lipopolysaccharide plus nigericin-treated J774A.1 cells. We conclude that CANA treatment alleviated insulin resistance and the progression of NAFLD in ob/ob and diabetic mice mice independent of the body weight change. CANA protected against the progression of NAFLD by inhibiting NLRP3-mediated pyroptosis and enhancing FGF21-ERK1/2 pathway activity in the liver. These findings suggest the therapeutic potential of sodium-glucose co-transporter2 inhibitors in the treatment of NAFLD.

Differences of Regional Fat Distribution Measured by Magnetic Resonance Imaging According to Obese Phenotype in Koreans

Background: Obesity is commonly associated with a high risk of metabolic disorders, and obesity-related metabolic abnormalities are affected by some specific obesity phenotypes, regional fat distribution, and body mass index. However, few studies have investigated the relationship between obesity phenotypes and regional fat distribution in Korean subjects. This study aimed to assess regional fat distribution by gender using magnetic resonance imaging (MRI), and to identify a link between fat distribution and metabolic disorders in Korean subjects. Methods: This study included 35 Korean subjects (20 women, 15 men) who were classified into two groups by gender, and further divided into two groups based on their obesity phenotype: a metabolically abnormal obesity (MAO) and metabolically healthy obesity (MHO) group. Fat distribution was measured using MRI. The blood parameters were measured using a commercially available kit. Results: Women in the MAO group had more risk factors for metabolic abnormalities than those in the MHO group. Serum glucose, triglyceride, and high-density lipoprotein cholesterol (HDL-C) levels were also significantly higher in women with MAO than in those with MHO. The intermuscular adipose tissue (IMAT) of women with MAO was significantly higher than that of women with MHO. Serum HDL-C level was negatively correlated with IMAT, whereas leptin showed a positive correlation with IMAT in all subjects. Conclusions: Metabolic abnormalities according to obesity phenotype posed a higher risk in women than that in men. These findings suggest that an understanding of gender differences in relation to the association between obesity and metabolic risk would be helpful to reduce the prevalence of obesity.

Intramuscular sex steroid hormones are reduced after resistance training in postmenopausal women, but not affected by estrogen therapy

Animal and human studies suggest that low concentrations of circulating sex steroid hormones play a critical role in the accelerated loss of muscle mass and strength after menopause. The skeletal muscle can produce sex steroid hormones locally, however, their presence and regulation remain mostly elusive. The purpose of this study was to examine sex steroid hormone concentrations in skeletal muscle biopsies from postmenopausal women before and after 12-weeks of resistance training with (n = 15) or without (n = 16) estrogen therapy, and after acute exercise. Furthermore, associations between circulating sex hormones, intramuscular sex steroid hormones and muscle parameters related to muscle strength, mass and quality were elucidated. Blood and muscle samples, body composition (DXA-scan), muscle size (MR), and muscle strength measures were determined before and after the intervention. An additional blood and muscle sample was collected after the last resistance exercise bout. The results demonstrated reduced intramuscular estradiol, testosterone and dehydroepiandrosterone (DHEA) concentrations after resistance training irrespective of estrogen therapy. Acute exercise had no effect on intramuscular sex hormone levels. Low circulating levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) associated with high muscle mass at baseline, and a decline in circulating FSH after the intervention associated with a greater gain in muscle cross-sectional area in response to the resistance training. In conclusion, intramuscular estradiol, testosterone and DHEA were reduced by resistance training and unaffected by changes in circulating estrogen levels induced by estrogen therapy. Serum FSH and LH were superior predictors of muscle mass compared to other circulating and intramuscular sex steroid hormones.

Dynapenic-abdominal obesity as an independent risk factor for chronic kidney disease in postmenopausal women: a population-based cohort study

OBJECTIVE

Low muscle strength and obesity lead to a higher risk of chronic kidney disease (CKD). Perimenopause is associated with a natural decline in muscle strength and an increase in visceral adiposity. Dynapenic obesity, which is the coexistence of low muscle strength and obesity, is expected to synergistically increase the prevalence of CKD in postmenopausal women. The aim of this study was to determine combined associations of dynapenia and obesity with CKD in postmenopausal women.

METHODS

This study used data from the Korean National Health and Nutrition Examination Survey, 2016 to 2019. The study included 4,525 postmenopausal women aged 42 to 80 years that were classified into four groups based on waist circumference (≥85 cm) and hand grip strength (<18 kg): normal, dynapenic, obese, or dynapenic-obese. According to the Kidney Disease: Improving Global Outcomes, we defined CKD as an estimated glomerular filtration rate <60 mL/min per 1.73 m2. Complex sample logistic regression models were conducted to determine the relationships among coexistence of dynapenia, abdominal obesity, and the risk of CKD.

RESULTS

Dynapenic-abdominal obese group displayed lower estimated glomerular filtration rate levels than other groups (P < 0.05 for all data). The prevalence rates of CKD were 15.5%, 7.8%, 6.2%, and 2.4% in the dynapenic-abdominal obese, dynapenic, abdominal obese, and normal groups, respectively (P < 0.001). Complex sample logistic regression analyses, after adjusting for age, height, health behaviors, and comorbidities, showed that the odds ratio for CKD with respect to dynapenic-abdominal obesity was 1.82 (95% confidence interval, 1.19-2.79) and to abdominal obesity was 1.54 (95% confidence interval, 1.07-2.22) than in the normal group.

CONCLUSIONS

This study demonstrated that dynapenic-abdominal obesity, as determined by low handgrip strength and high waist circumference values, was associated with increased risk of CKD in postmenopausal women.

Lipids and diastolic dysfunction: Recent evidence and findings

AIM

Diastolic dysfunction is the decreased flexibility of the left ventricle due to the impaired ability of the myocardium to relax and plays an important role in the pathogenesis of heart failure. Lipid metabolism is a well-known contributor to cardiac conditions, including ventricular function. In this article, we aimed to review the literature addressing the connections between lipids, their storage, and metabolism with left ventricular diastolic dysfunction.

DATA SYNTHESIS

We searched Google scholar, Pubmed, Embase and Researchgate for our keywords: "Diastolic function", "Fat" and "Lipid profile". Initially, 250 articles were selected by title and 84 of them were chosen as most relevant and directly reviewed.

CONCLUSIONS

Alterations of lipid metabolism in cardiac muscle and cardiac lipid content can occur in many conditions, including consumption of a high-fat diet, obesity, metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD). These conditions induce alterations in myocardial lipid metabolism, increase myocardial fat content and epicardial fat thickness and increase inflammation and oxidative stress which ultimately lead to cardiac lipotoxicity and diastolic dysfunction. The effects of lipids on diastolic function can differ based on gender. Lipid profile and metabolism are as important in the pathogenesis of diastolic dysfunction as they are in other cardiovascular disorders. A more careful look at cardiac lipid metabolism in molecular, histological and gross levels results in more precise understanding of its role in myocardial function and leads to development of potential treatments for diastolic dysfunction.

Increased liver fat associates with severe metabolic perturbations in low birth weight men

OBJECTIVE

Ectopic liver fat deposition, resulting from impaired subcutaneous adipose tissue expandability, may represent an age-dependent key feature linking low birth weight (LBW) with increased risk of type 2 diabetes (T2D). We examined whether presumably healthy early middle-aged, non-obese LBW subjects exhibit increased liver fat content, whether increased liver fat in LBW is associated with the severity of dysmetabolic traits and finally whether such associations may be confounded by genetic factors.

METHODS

Using 1H magnetic resonance spectroscopy, we measured hepatic fat content in 26 early middle-aged, non-obese LBW and 22 BMI-matched normal birth weight (NBW) males. Endogenous glucose production was measured by stable isotopes, and a range of plasma adipokine and gut hormone analytes were measured by multiplex ELISA. Genetic risk scores were calculated from genome-wide association study (GWAS) data for birth weight, height, T2D, plasma cholesterol and risk genotypes for non-alcoholic fatty liver disease (NAFLD).

RESULTS

The LBW subjects had significantly increased hepatic fat content compared with NBW controls (P= 0.014), and 20% of LBW vs no controls had overt NAFLD. LBW subjects with NAFLD displayed widespread metabolic changes compared with NBW and LBW individuals without NAFLD, including hepatic insulin resistance, plasma adipokine and gut hormone perturbations as well as dyslipidemia. As an exception, plasma adiponectin levels were lower in LBW subjects both with and without NAFLD as compared to NBW controls. Genetic risk for selected differential traits did not differ between groups.

CONCLUSION

Increased liver fat content including overt NAFLD may be on the critical path linking LBW with increased risk of developing T2D in a non-genetic manner.

Multimodal analysis suggests differential immuno-metabolic crosstalk in lung squamous cell carcinoma and adenocarcinoma

Immunometabolism within the tumor microenvironment is an appealing target for precision therapy approaches in lung cancer. Interestingly, obesity confers an improved response to immune checkpoint inhibition in non-small cell lung cancer (NSCLC), suggesting intriguing relationships between systemic metabolism and the immunometabolic environment in lung tumors. We hypothesized that visceral fat and ¹⁸F-Fluorodeoxyglucose uptake influenced the tumor immunometabolic environment and that these bidirectional relationships differ in NSCLC subtypes, lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). By integrating ¹⁸F-FDG PET/CT imaging, bulk and single-cell RNA-sequencing, and histology, we observed that LUSC had a greater dependence on glucose than LUAD. In LUAD tumors with high glucose uptake, glutaminase was downregulated, suggesting a tradeoff between glucose and glutamine metabolism, while in LUSC tumors with high glucose uptake, genes related to fatty acid and amino acid metabolism were also increased. We found that tumor-infiltrating T cells had the highest expression of glutaminase, ribosomal protein 37, and cystathionine gamma-lyase in NSCLC, highlighting the metabolic flexibility of this cell type. Further, we demonstrate that visceral adiposity, but not body mass index (BMI), was positively associated with tumor glucose uptake in LUAD and that patients with high BMI had favorable prognostic transcriptional profiles, while tumors of patients with high visceral fat had poor prognostic gene expression. We posit that metabolic adjunct therapy may be more successful in LUSC rather than LUAD due to LUAD's metabolic flexibility and that visceral adiposity, not BMI alone, should be considered when developing precision medicine approaches for the treatment of NSCLC.

The effects of low-intensity exercise on cardiac glycogenesis and glycolysis in male and ovariectomized female rats on a fructose-rich diet

We previously reported that low-intensity exercise prevented cardiac insulin resistance induced by a fructose-rich diet (FRD). To examine whether low-intensity exercise could prevent the disturbances of key molecules of cardiac glucose metabolism induced by FRD in male and ovariectomized (ovx) female rats, animals were exposed to 10% fructose solution (SF) or underwent both fructose diet and exercise (EF). Exercise prevented a decrease in cardiac GSK-3β phosphorylation induced by FRD in males (p < .001 vs. SF). It also prevented a decrease in PFK-2 phosphorylation in ovx females (p < .001 vs. SF) and increased the expression of PFK-2 in males (p < .05 vs. control). Exercise did not prevent a decrease in plasma membrane GLUT1 and GLUT4 levels in ovx females on FRD. The only effect of exercise on glucose transporters that could be indicated as beneficial is an augmented GLUT4 protein expression in males (p < .05 vs. control). Obtained results suggest that low-intensity exercise prevents harmful effects of FRD towards cardiac glycogenesis in males and glycolysis in ovx females. PRACTICAL APPLICATIONS: Low-intensity exercise, equivalent to brisk walking, was able to prevent disturbances in cardiac glycolysis regulation in ovx female and the glycogen synthesis pathway in male rats. In terms of human health, although molecular mechanisms of beneficial effects of exercise on cardiac glucose metabolism vary between genders, low-intensity running may be a useful non-pharmacological approach in the prevention of cardiac metabolic disorders in both men and postmenopausal women.

Changes in abdominal subcutaneous adipose tissue phenotype following menopause is associated with increased visceral fat mass

Menopause is associated with a redistribution of adipose tissue towards central adiposity, known to cause insulin resistance. In this cross-sectional study of 33 women between 45 and 60 years, we assessed adipose tissue inflammation and morphology in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) across menopause and related this to menopausal differences in adipose tissue distribution and insulin resistance. We collected paired SAT and VAT biopsies from all women and combined this with anthropometric measurements and estimated whole-body insulin sensitivity. We found that menopause was associated with changes in adipose tissue phenotype related to metabolic dysfunction. In SAT, postmenopausal women showed adipocyte hypertrophy, increased inflammation, hypoxia and fibrosis. The postmenopausal changes in SAT was associated with increased visceral fat accumulation. In VAT, menopause was associated with adipocyte hypertrophy, immune cell infiltration and fibrosis. The postmenopausal changes in VAT phenotype was associated with decreased insulin sensitivity. Based on these findings we suggest, that menopause is associated with changes in adipose tissue phenotype related to metabolic dysfunction in both SAT and VAT. Whereas increased SAT inflammation in the context of menopause is associated with VAT accumulation, VAT morphology is related to insulin resistance.

Preserved postprandial suppression of bone turnover markers, despite increased fasting levels, in postmenopausal women

CONTEXT

Menopause leads to an increased bone turnover associated with a high risk of fractures. Bone turnover is inhibited by meal intake, to some extent mediated by gut hormones, and interventions based on these endocrine changes may have potential in future prevention of osteoporosis.

OBJECTIVE

To investigate whether postmenopausal women exhibit postprandial suppression of bone turnover markers to the same extent as premenopausal women, despite higher fasting levels. Furthermore, to assess whether menopausal differences in bone turnover markers are related to postmenopausal changes in plasma gut hormone levels.

METHODS

A cross-sectional study of 21 premenopausal, 9 perimenopausal, and 24 postmenopausal women between 45 and 60 years of age. Serum/plasma levels of bone turnover markers and gut hormones were investigated during a 120 min oral glucose tolerance test. Bone turnover markers included N-terminal propeptide of type-I procollagen (PINP, bone formation marker) and carboxyterminal collagen I crosslinks (CTX-I, bone resorption marker). Gut hormone secretion was evaluated from responses of glucagon-like peptide-1 (GLP-1), glucagon-like peptide-2 (GLP-2) and glucose-dependent insulinotropic polypeptide (GIP).

RESULTS

Fasting levels of s-CTX-I were increased in peri- and postmenopausal women compared to premenopausal women (p = 0.001). Despite higher fasting levels, the relative postprandial s-CTX-I suppression was comparable across menopausal status (p = 0.14). Fasting levels of s-PINP were also increased in postmenopausal women compared to premenopausal women (p < 0.001) with comparable and modest s-PINP suppression over menopause (p = 0.13). Postprandial plasma GLP-1 (p = 0.006) and GLP-2 (p = 0.01) were significantly increased in postmenopausal women compared to premenopausal women while GIP responses were slightly increased in the perimenopausal group (p = 0.02) but comparable between pre- and postmenopausal women. None of the postprandial gut hormone increases predicted postprandial bone turnover suppression in these women.

CONCLUSIONS

Glucose-induced suppression of bone turnover markers is preserved in postmenopausal women, despite significantly higher fasting values, indicating that CTX-I lowering treatments based on these postprandial mechanisms might be a feasible strategy to prevent postmenopausal osteoporosis.

Impacts of Selected Dietary Nutrient Intakes on Skeletal Muscle Insulin Sensitivity and Applications to Early Prevention of Type 2 Diabetes

As the largest tissue in the body, skeletal muscle not only plays key roles in movement and glucose uptake and utilization but also mediates insulin sensitivity in the body by myokines. Insulin resistance in the skeletal muscle is a major feature of type 2 diabetes (T2D). A weakened response to insulin could lead to muscle mass loss and dysfunction. Increasing evidence in skeletal muscle cells, rodents, nonhuman primates, and humans has shown that restriction of caloric or protein intake positively mediates insulin sensitivity. Restriction of essential or nonessential amino acids was reported to facilitate glucose utilization and regulate protein turnover in skeletal muscle under certain conditions. Furthermore, some minerals, such as zinc, chromium, vitamins, and some natural phytochemicals such as curcumin, resveratrol, berberine, astragalus polysaccharide, emodin, and genistein, have been shown recently to protect skeletal muscle cells, mice, or humans with or without diabetes from insulin resistance. In this review, we discuss the roles of nutritional interventions in the regulation of skeletal muscle insulin sensitivity. A comprehensive understanding of the nutritional regulation of insulin signaling would contribute to the development of tools and treatment programs for improving skeletal muscle health and for preventing T2D.

Adipose tissue in health and disease

Adipose, or fat, tissue (AT) was once considered an inert tissue that primarily existed to store lipids, and was not historically recognized as an important organ in the regulation and maintenance of health. With the rise of obesity and more rigorous research, AT is now recognized as a highly complex metabolic organ involved in a host of important physiological functions, including glucose homeostasis and a multitude of endocrine capabilities. AT dysfunction has been implicated in several disease states, most notably obesity, metabolic syndrome and type 2 diabetes. The study of AT has provided useful insight in developing strategies to combat these highly prevalent metabolic diseases. This review highlights the major functions of adipose tissue and the consequences that can occur when disruption of these functions leads to systemic metabolic dysfunction.

Tunicamycin-Induced Endoplasmic Reticulum Stress Mediates Mitochondrial Dysfunction in Human Adipocytes

CONTEXT

Dysfunctional endoplasmic reticulum (ER) and mitochondria are known to contribute to the pathology of metabolic disease. This damage may occur, in part, as a consequence of ER-mitochondria cross-talk in conditions of nutrient excess such as obesity. To date, insight into this dynamic relationship has not been characterized in adipose tissue. Therefore, this study investigated whether ER stress contributes to the development of mitochondrial inefficiency in human adipocytes from lean and obese participants.

METHODS

Human differentiated adipocytes from Chub-S7 cell line and primary abdominal subcutaneous adipocytes from lean and obese participants were treated with tunicamycin to induce ER stress. Key parameters of mitochondrial function were assessed, including mitochondrial respiration, membrane potential (MMP), and dynamics.

RESULTS

ER stress led to increased respiratory capacity in a model adipocyte system (Chub-S7 adipocytes) in a concentration and time dependent manner (24 h: 23%↑; 48 h: 68%↑, P < 0.001; 72 h: 136%↑, P < 0.001). This corresponded with mitochondrial inefficiency and diminished MMP, highlighting the formation of dysfunctional mitochondria. Morphological analysis revealed reorganization of mitochondrial network, specifically mitochondrial fragmentation. Furthermore, p-DRP1, a key protein in fission, significantly increased (P < 0.001). Additionally, adipocytes from obese subjects displayed lower basal respiration (49%↓, P < 0.01) and were unresponsive to tunicamycin in contrast to their lean counterparts, demonstrating inefficient mitochondrial oxidative capacity.

CONCLUSION

These human data suggest that adipocyte mitochondrial inefficiency is driven by ER stress and exacerbated in obesity. Nutrient excess-induced ER stress leads to mitochondrial dysfunction that may therefore shift lipid deposition ectopically and thus have further implications on the development of related metabolic disorders.

Increased systemic inflammation and altered distribution of T-cell subsets in postmenopausal women

Aim

To investigate markers of systemic inflammation in pre- and postmenopausal women and identify possible predictors of systemic inflammation with menopause.

Methods

Cross-sectional study of 69 healthy women between 45- and 60 years. Blood samples were collected to assess leukocyte subsets and plasma cytokines. MRI and DXA scans were performed to assess body composition. Through uni- and multivariate analyses, follicle-stimulating hormone (FSH), visceral fat mass and age were evaluated as predictors of systemic inflammation in relation to menopause.

Results

Postmenopausal women tended to have higher leukocyte counts (5.4 x10⁹ vs. 4.9 x10⁹ cells/l, p = 0.05) reflected in increased total lymphocytes (1.8 x10⁹ vs. 1.6 x10⁹ cells/l, p = 0.01) and monocytes (0.5 x10⁹ vs. 0.4 x10⁹ cells/l, p = 0.02), compared to premenopausal women. Increased visceral fat mass was a strong predictor of high leukocyte subsets. Postmenopausal women had higher plasma TNF-α (2.24 vs. 1.91 pg/ml, p = 0.01) and IL-6 (0.45 vs. 0.33 pg/ml, p = 0.004) compared to premenopausal women and high FSH was a significant predictor of increased plasma TNF-α, IL-1β and IL-6. Menopause was further associated with increased T-cells (1,336 vs. 1,128 cells/μl, p = 0.04) reflected in significantly higher counts of exhausted-, senescent-, and memory CD4+ T-cell subsets.

Conclusions

Menopause is associated with increased systemic inflammation as well as exhausted- and senescent T-cells. We suggest, that both increased visceral fat mass and declining sex hormone levels might contribute to postmenopausal systemic inflammation and calls for further large-scale studies to confirm these findings.

Perimenopause, body fat, metabolism and menopausal symptoms in relation to serum markers of adiposity, inflammation and digestive metabolism

BACKGROUND

Perimenopausal women gain weight that may alter inflammatory status, endocrine equilibrium, and the intensity of vasomotor symptoms.

OBJECTIVE

To measure serum levels of markers related to adiposity, inflammation/angiogenesis and digestive metabolism and correlate them with body mass index (BMI), waist-to-hip ratio (WHR), metabolic parameters and menopausal symptoms (assessed with the 10-item Cervantes Scale [CS-10]).

METHODS

Serum of perimenopausal women (n = 24), STRAW stages-2 and -1, was analyzed using the Bio-Plex 200 System technology to assess 30 proposed analytes. The MetS was defined by the American Heart Association criteria and women were divided as: normal BMI (NBMI), excessive BMI (EBMI), and EBMI with MetS (EBMI-MetS).

RESULTS

Weight, BMI, abdominal circumference, WHR, systolic blood pressure, glucose and triglyceride levels were significantly higher and high-density lipoprotein cholesterol (HDL-C) was lower in EBMI-MetS women compared to NBMI ones. Insulin, C-peptide, resistin, adipsin, GIP, leptin, IL-6, FGF21 and PAI-1 levels were significantly higher and ghrelin and IGFBP-1 lower in EBMI-MetS women as compared to NBMI ones. Spearman's correlation of pooled data showed a significant positive correlation between abdominal perimeter and WHR and C-peptide, insulin, adipsin, resistin, leptin, PAI-1 and FGF21 and a negative correlation with IGFBP-1 levels. Total CS-10 scores and hot flush intensity did not differ between studied groups, yet positively correlated with anthropometric values but not with studied analytes.

CONCLUSION

Perimenopausal women with EBMI and the MetS showed an altered metabolic profile, but no differences in menopausal symptoms which also did not correlate with changes in studied biomarkers.

Thigh Muscle Fat Infiltration Is Associated With Impaired Physical Performance Despite Remission in Cushing's Syndrome

CONTEXT

Muscle weakness is common in patients with Cushing's syndrome (CS) and may persist after the resolution of hypercortisolism. Intramuscular fatty infiltration has been associated with the deterioration of muscle performance in several conditions.

OBJECTIVES

To quantify the degree of fatty infiltration in the thigh muscles of "cured" CS patients and evaluate the relationship between intramuscular fatty infiltration and physical performance.

DESIGN

This was a cross-sectional study.

SETTING

Tertiary referral center.

PATIENTS

Thirty-six women with CS in remission, and 36 controls matched for age, BMI, menopausal status, and level of physical activity.

MAIN OUTCOME MEASURES

We analyzed the percentage fat fraction (FF) of the thigh muscles in the anterior, posterior, and combined anterior and posterior compartments using MRI and 2-point Dixon sequence. We assessed muscle function and strength using the following tests: gait speed (GS), timed up and go (TUG), 30-second chair stand, and hand grip strength.

RESULTS

Fat fraction in all the compartments analyzed was increased in patients as compared with controls. The performance on TUG, 30-second chair stand, and GS was more impaired in CS patients versus controls. In patients, greater FF was negatively associated with performance on functional tests. Fat fraction in the combined anterior and posterior compartments predicted performance on TUG (ß 0.626, P < 0.000) and GS (ß -0.461, P = 0.007), after adjusting for age, BMI, menopausal status, and muscle mass.

CONCLUSIONS

Thigh muscle fatty infiltration is increased in "cured" CS patients and is associated with poorer muscle performance. Future studies are needed to establish therapeutic strategies to improve muscle weakness in these patients.

Analysis of muscle, hip, and subcutaneous fat in osteoporosis patients with varying degrees of fracture risk using 3T Chemical Shift Encoded MRI

Osteoporosis (OP) is a major disease that affects 200 million people worldwide. Fatty acid metabolism plays an important role in bone health and plays an important role in bone quality and remodeling. Increased bone marrow fat quantity has been shown to be associated with a decrease in bone mineral density (BMD), which is used to predict fracture risk. Chemical-Shift Encoded magnetic resonance imaging (CSE-MRI) allows noninvasive and quantitative assessment of adipose tissues (AT). The aim of our study was to assess hip or proximal femoral bone marrow adipose tissue (BMAT), thigh muscle (MUS), and subcutaneous adipose tissue (SAT) in 128 OP subjects matched for age, BMD, weight and height with different degrees of fracture risk assessed through the FRAX score (low, moderate and high). Our results showed an increase in BMAT and in MUS in high compared to low fracture risk patients. We also assessed the relationship between fracture risk as assessed by FRAX and AT quantities. Overall, the results of this study suggest that assessment of adipose tissue via 3T CSE-MRI provides insight into the pathophysiology fracture risk by showing differences in the bone marrow and muscle fat content in subjects with similarly osteoporotic BMD as assessed by DXA, but with varying degrees of fracture risk as assessed by FRAX.

Intramyocardial Triglycerides Among Women With vs Without HIV: Hormonal Correlates and Functional Consequences

CONTEXT

Women with HIV (WHIV) on anti-retroviral therapy (ART) are living longer but facing heightened vulnerability to heart failure.

OBJECTIVE

We investigated metabolic/hormonal/immune parameters relating to diastolic dysfunction-a precursor to heart failure-among WHIV without known cardiovascular disease (CVD).

DESIGN AND OUTCOME MEASURES

Nineteen ART-treated WHIV and 11 non-HIV-infected women without known CVD enrolled and successfully completed relevant study procedures [cardiac magnetic resonance spectroscopy (MRS) and cardiac MRI]. Groups were matched on age and body mass index. Primary outcome measures included intramyocardial triglyceride content (cardiac MRS) and diastolic function (cardiac MRI). Relationships between intramyocardial triglyceride content and clinical parameters were also assessed.

RESULTS

Among WHIV (vs non-HIV-infected women), intramyocardial triglyceride content was threefold higher [1.2 (0.4, 3.1) vs 0.4 (0.1, 0.5)%, P = 0.01], and diastolic function was reduced (left atrial passive ejection fraction: 27.2 ± 9.6 vs 35.9 ± 6.4%, P = 0.007). There was a strong inverse relationship between intramyocardial triglyceride content and diastolic function (ρ = -0.62, P = 0.004). Among the whole group, intramyocardial triglyceride content did not relate to chronologic age but did increase across the reproductive aging spectrum (P = 0.02). HIV status and reproductive aging status remained independent predictors of intramyocardial triglyceride content after adjusting for relevant cardiometabolic parameters (overall model R2 = 0.56, P = 0.003; HIV status P = 0.01, reproductive aging status P = 0.02).

CONCLUSIONS

For asymptomatic WHIV, increased intramyocardial triglyceride content is associated with diastolic dysfunction. Moreover, relationships between intramyocardial triglyceride accumulation and women's reproductive aging are noted.

Circulating CRP Levels Are Associated with Epicardial and Visceral Fat Depots in Women with Metabolic Syndrome Criteria

Sexual dimorphism accounts for significant differences in adipose tissue mass and distribution. However, how the crosstalk between visceral and ectopic fat depots occurs and which are the determinants of ectopic fat expansion and dysfunction remains unknown. Here, we focused on the impact of gender in the crosstalk between visceral and epicardial fat depots and the role of adipocytokines and high-sensitivity C-reactive protein (hs-CRP). A total of 141 outward patients (both men and women) with one or more defining criteria for metabolic syndrome (MetS) were consecutively enrolled. For all patients, demographic and clinical data were collected and ultrasound assessment of visceral adipose tissue (VFth) and epicardial fat (EFth) thickness was performed. Hs-CRP and adipocytokine levels were assessed by enzyme-linked immunosorbent assay (ELISA). Men were characterized by increased VFth and EFth (p-value < 0.001 and 0.014, respectively), whereas women showed higher levels of adiponectin and leptin (p-value < 0.001 for both). However, only in women VFth and EFth significantly correlated between them (p = 0.013) and also with leptin (p < 0.001 for both) and hs-CRP (p = 0.005 and p = 0.028, respectively). Linear regression confirmed an independent association of both leptin and hs-CRP with VFth in women, also after adjustment for age and MetS (p = 0.012 and 0.007, respectively). In conclusion, men and women present differences in epicardial fat deposition and systemic inflammation. An intriguing association between visceral/epicardial fat depots and chronic low-grade inflammation also emerged. In women Although a further validation in larger studies is needed, these findings suggest a critical role of sex in stratification of obese/dysmetabolic patients.

Myocardial adipose deposition and the development of heart failure with preserved ejection fraction

AIMS

It has been proposed that an increase of myocardial adiposity is related to left ventricular (LV) diastolic dysfunction. The specific roles of myocardial steatosis including epicardial fat and intramyocardial fat for diastolic function are unknown in those patients suffering heart failure (HF) with reduced (HFrEF) or preserved ejection fraction (HFpEF). This study aims to determine the complex relationship between myocardial adiposity in patients with HFrEF or HFpEF.

METHODS AND RESULTS

Using cardiac magnetic resonance imaging (CMRI), myocardial steatosis was measured in 305 subjects (34 patients with HFrEF, 163 with HFpEF, and 108 non-HF controls). We also evaluated cardiac structure and diastolic and systolic function by echocardiography and CMRI. Patients with HFpEF had significantly more intramyocardial fat than HFrEF patients or non-HF controls [intramyocardial fat content (%), 1.56 (1.26, 1.89) vs. 0.75 (0.50, 0.87) and 1.0 (0.79, 1.15), P < 0.05]. Intramyocardial fat amount (%) was higher in HFpEF women than in men [1.91% (1.17%, 2.32%) vs. 1.22 (0.87%, 2.02%), P = 0.01]. When estimated by CMRI (left ventricular peak filling rate), echocardiographic E/e' level, or left atrial volume index, intramyocardial fat correlated with LV diastolic dysfunction parameters in HFpEF patients, and this was independent of age, co-morbidities, body mass index, gender, and myocardial fibrosis (standardized coefficient: β = -0.34, P = 0.03; β = 0.29, P = 0.025; and β = 0.25, P = 0.02, respectively).

CONCLUSIONS

Patients with HFpEF had significantly more intramyocardial fat than HFrEF patients or non-HF controls. Independent of risk factors or gender, intramyocardial fat correlated with LV diastolic dysfunction parameters in HFpEF patients.

Luteolin reduces adipose tissue macrophage inflammation and insulin resistance in postmenopausal obese mice

Previously, we showed that loss of ovarian function in mice fed high-fat diet exacerbated insulin resistance and adipose tissue inflammation. In the current study, we tested whether consumption of luteolin, an anti-inflammatory flavonoid, could mitigate adipose tissue inflammation and insulin resistance in obese ovariectomized mice. Nine-week-old ovariectomized C57BL/6 mice were fed a low-fat diet, high-fat diet (HFD) or HFD supplemented with 0.005% luteolin (HFD+L) for 16 weeks. Results showed no difference in body weight or fat mass between mice fed HFD+L and those fed HFD. However, luteolin supplementation resulted in lower CD11c⁺ macrophages in gonadal adipose tissue, as well as a trend toward lower macrophage infiltration. Luteolin supplementation also significantly lowered mRNA expression of inflammatory and M1 markers MCP-1, CD11c, TNF-α and IL-6, while maintaining expression of M2 marker MGL1. Consistent with this, the in vitro luteolin treatment, with or without the presence of estrogen, inhibited lipopolysaccharide-induced polarization of RAW 264.7 cells toward M1 phenotype. We further found that luteolin supplementation protected mice from insulin resistance induced by HFD consumption; this improved insulin resistance was correlated with reductions in CD11c⁺ adipose tissue macrophages. Taken together, these findings indicate that dietary luteolin supplementation attenuates adipose tissue inflammation and insulin resistance found in mice with loss of ovarian function coupled with an HFD intake, and this effect may be partly mediated through suppressing M1-like polarization of macrophages in adipose tissue. These results have clinical implication in implementing dietary intervention for prevention of metabolic syndrome associated with postmenopause and obesity.

The glucocorticoid receptor agonistic modulators CpdX and CpdX-D3 do not generate the debilitating effects of synthetic glucocorticoids

Seventy years after the discovery of their anti-inflammatory properties, glucocorticoids (GCs) remain the mainstay treatment for major allergic and inflammatory disorders, such as atopic dermatitis, asthma, rheumatoid arthritis, colitis, and conjunctivitis, among others. However, their long-term therapeutical administration is limited by major debilitating side effects, e.g., skin atrophy, osteoporosis, Addison-like adrenal insufficiency, fatty liver, and type 2 diabetes syndrome, as well as growth inhibition in children. These undesirable side effects are mostly related to GC-induced activation of both the direct transactivation and the direct transrepression functions of the GC receptor (GR), whereas the activation of its GC-induced indirect tethered transrepression function results in beneficial anti-inflammatory effects. We have reported in the accompanying paper that the nonsteroidal compound CpdX as well as its deuterated form CpdX-D3 selectively activate the GR indirect transrepression function and are as effective as synthetic GCs at repressing inflammations generated in several mouse models of major pathologies. We now demonstrate that these CpdX compounds are bona fide selective GC receptor agonistic modulators (SEGRAMs) as none of the known GC-induced debilitating side effects were observed in the mouse upon 3-mo CpdX treatments. We notably report that, unlike that of GCs, the administration of CpdX to ovariectomized (OVX) mice does not induce a fatty liver nor type 2 diabetes, which indicates that CpdX could be used in postmenopausal women as an efficient "harmless" GC substitute.

Metabolic control and sex: A focus on inflammatory-linked mediators

Men and women have many differing biological and physiological characteristics. Thus, it is no surprise that the control of metabolic processes and the mechanisms underlying metabolic-related diseases have sex-specific components. There is a clear metabolic sexual dimorphism in that up until midlife, men have a far greater likelihood of acquiring cardio-metabolic disease than women. Following menopause, however, this difference is reduced, suggestive of a protective role of the female sex hormones. Inflammatory processes have been implicated in the pathogenesis of cardio-metabolic disease with human studies correlating metabolic disease acquisition or risk with levels of various inflammatory markers. Rodent studies employing genetic modifications or novel pharmacological approaches have provided mechanistic insight into the role of these inflammatory mediators. Sex differences impact inflammatory processes and the subsequent biological response. As a consequence, this may affect how inflammation alters metabolic processes between the sexes. Recently, some of our work in the field of inflammatory genes and metabolic control identified a sexual dimorphism in a preclinical model and caused us to question the frequency and scale of such findings in the literature. This review concentrates on inflammatory-related signalling in relation to obesity, insulin resistance, and type 2 diabetes and highlights the differences observed between males and females. Differences in the activation and signalling of various inflammatory genes and proteins present another reason why studying both male and female patients or animals is important in the context of understanding and finding therapeutics for metabolic-related disease. LINKED ARTICLES: This article is part of a themed section on The Importance of Sex Differences in Pharmacology Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.21/issuetoc.

Targeting White Adipose Tissue with Exercise or Bariatric Surgery as Therapeutic Strategies in Obesity

Adipose tissue is critical to whole-body energy metabolism and has become recognized as a bona fide endocrine organ rather than an inert lipid reservoir. As such, adipose tissue is dynamic in its ability to secrete cytokines, free fatty acids, lipokines, hormones and other factors in response to changes in environmental stimuli such as feeding, fasting and exercise. While excess adipose tissue, as in the case of obesity, is associated with metabolic complications, mass itself is not the only culprit in obesity-driven metabolic abnormalities, highlighting the importance of healthy and metabolically adaptable adipose tissue. In this review, we discuss the fundamental cellular processes of adipose tissue that become perturbed in obesity and the impact of exercise on these processes. While both endurance and resistance exercise can promote positive physiological adaptations in adipose tissue, endurance exercise has a more documented role in remodeling adipocytes, increasing adipokine secretion and fatty acid mobilization and oxidation during post-exercise compared with resistance exercise. Exercise is considered a viable therapeutic strategy for the treatment of obesity to optimize body composition, in particular as an adjuvant therapy to bariatric surgery; however, there is a gap in knowledge of the molecular underpinnings of these exercise-induced adaptations, which could provide more insight and opportunity for precision-based treatment strategies.

Menopause and Dry Eye Syndrome

Dry eye syndrome is a common ophthalmic complaint. Women, especially menopausal women with comorbidities, are at greater risk for developing dry eye syndrome and subsequent negative effects on their overall eye health. In this article, I review the anatomy and physiology of the ocular surface of the eye, pathophysiology of dry eyes and its complications, risk factors for menopausal women, and assessment tools that nurses can use. Implications for nursing practice are discussed, and a case example illustrates clinical points.