Sex-dependent Depot Differences in Adipose Tissue Development and Function; Role of Sex Steroids

Sex- and depot-specific differences in cellular insulin responsiveness during adipose expansion

BACKGROUND

Adipose tissue distribution, metabolism, and expansion capacity exhibit notable sex- and depot-specific differences. Herein, we monitored adipocyte traits related to insulin responsiveness and glucose transport during adipose expansion in visceral and subcutaneous fat from male and female mice.

MATERIALS AND METHODS

Adipocytes were isolated from perigonadal and inguinal adipose tissue of chow-fed female and male C57Bl6/J mice and assessed for adipocyte size distribution using a coulter counter; glucose uptake and cytosolic volume were measured using glucose tracer assays. GLUT1, GLUT4, and IRS-1 protein levels were assessed by western blot. Pharmacological inhibition (BAY876) of GLUT1 and GLUT4 was used to resolve their respective contribution to cellular glucose transport.

KEY FINDINGS

Independent of adiposity or sex, visceral adipocytes were larger and displayed higher glucose transport, cytosolic volume, and GLUT4 levelsthan subcutaneous adipocytes. GLUT1 content was higher in subcutaneous than visceral adipocytes in both sexes. Pharmacological inhibition confirmed that GLUT1 contributes to <10 % of adipocyte glucose uptake, while GLUT4 facilitates most of both basal and insulin-stimulated glucose uptake. Females showed significantly higher basal and insulin-stimulated glucose transport, higher cytosolic volume, and greater GLUT4 and IRS-1 protein levels than males in both adipose depots. Interestingly, insulin responsiveness was preserved in female subcutaneous adipocytes but deteriorated in subcutaneous male adipocytes during adipose expansion.

SIGNIFICANCE

The improved insulin responsiveness, increased glucose transport, and higher levels of GLUT4 and IRS-1 in adipocytes might protect females from the adverse systemic effects linked to obesity. Insulin responsiveness was preserved in female subcutaneous adipocytes during adipose tissue expansion, which could contribute to the reduced risk of females to develop systemic insulin resistance.

Heart Rate Mystery Unveiled: Sex Differences in Human Sinoatrial Node Genes and Female Tachycardia

BACKGROUND

Despite over a century of clinical electrocardiographic studies showing that women exhibit a faster resting heart rate (HR), the mechanisms underlying sex differences in HR remain unresolved. Moreover, inappropriate sinus tachycardia primarily affects women, whereas men are at a higher risk for conduction block and atrial fibrillation. We hypothesized that the sexual dimorphism of genes responsible for sinoatrial node (SAN) pacemaking and signaling pathways may contribute to the sex differences in HR and susceptibility to arrhythmias.

METHODS

Human SAN central pacemaker and right atrial tissue were isolated from nondiseased ex vivo donor hearts. Gene expressions were quantified and validated using the transcriptomic panel and quantitative polymerase chain reaction. Gene set enrichment analysis, Ingenuity Pathway Analysis, and human-specific SAN models were utilized to define regulatory mechanisms and functional impacts of sex-biased gene transcription.

RESULTS

We identified differentially expressed region- and sex-specific genes, with gene sets enriched in HR regulation (eg, TBX3, HCN1) and metabolism (eg, ADIPOQ, LEP) pathways in female SAN. In contrast, differential genes and gene sets involved in collagen biosynthetic processes, fibrogenesis (eg, EGR1), and immune response (eg, IL6, CXCL8) pathways were enriched in males SAN and right atrial. Ingenuity Pathway Analysis predicted significant roles for TBX3 and estradiol in the sex-specific expression of genes involved in SAN function. Computational simulations showed that the sex-specific SAN differences in If (pacemaker current; HCN1) and ICa,L(L-type calcium current; CACNA1D) can explain the faster HR in female SAN, with female SAN having a lower threshold for inappropriate sinus tachycardia, whereas male SAN are more vulnerable to sinus arrest.

CONCLUSIONS

The human SAN exhibits region-specific sexual dimorphism in pacemaking gene sets. Higher expression of TBX3 and HCN1 in female SAN may underlie faster HR and increased susceptibility to inappropriate sinus tachycardia in women, whereas enriched gene sets related to inflammation and collagen biosynthesis in men may predispose them to conduction impairments and atrial fibrillation risk.

Sex and Depot Specific Adipocyte Proteome Profiling In Vivo via Intracellular Proximity Labeling

Adipose tissue has varying distributions and metabolic properties between the sexes. Inherent sex-specific differences in adipocytes may heighten the risk of metabolic disease in males. Analysis of the adipocyte proteome can potentially provide important insight. To enable cell-type specific proteomic profiling in vivo, we genetically engineered a mouse line for cell-type specific production of a promiscuous biotin ligase (BirA*G3) facilitating the rapid isolation of biotinylated cell-type specific proteomes. Adipocyte-specific activation of cytoplasmic BirA*G3 led to robust biotinylation of adipocyte proteins across all major fat depots. Comparison of brown adipose tissue (BAT) and subcutaneous white adipose tissue (SAT) proteomes identified 229 brown adipose-enriched and 35 white adipose-enriched proteins. Regional comparison of white fat depots revealed additional differences across depots. Comparison of male and female depots identified sexually dimorphic adipose proteins: AHNAK predominating in the male and ACOT2 in the female. These findings validate the genetic model and highlight insights to be gained through targeted profiling of adipocytes. The genetic tool adds to existing approaches for in vivo proximity profiling of cell-type specific proteome programs.

Sexual Dimorphism in Cardiometabolic Diseases: From Development to Senescence and Therapeutic Approaches

The global incidence and prevalence of cardiometabolic disorders have risen significantly in recent years. Although lifestyle choices in adulthood play a crucial role in the development of these conditions, it is well established that events occurring early in life can have an important effect. Recent research on cardiometabolic diseases has highlighted the influence of sexual dimorphism on risk factors, underlying mechanisms, and response to therapies. In this narrative review, we summarize the current understanding of sexual dimorphism in cardiovascular and metabolic diseases in the general population and within the framework of the Developmental Origins of Health and Disease (DOHaD) concept. We explore key risk factors and mechanisms, including the influence of genetic and epigenetic factors, placental and embryonic development, maternal nutrition, sex hormones, energy metabolism, microbiota, oxidative stress, cell death, inflammation, endothelial dysfunction, circadian rhythm, and lifestyle factors. Finally, we discuss some of the main therapeutic approaches, responses to which may be influenced by sexual dimorphism, such as antihypertensive and cardiovascular treatments, oxidative stress management, nutrition, cell therapies, and hormone replacement therapy.

Artificial intelligence-based body composition analysis using computed tomography images predicts both prevalence and incidence of diabetes mellitus

AIM/INTRODUCTION

We assess the efficacy of artificial intelligence (AI)-based, fully automated, volumetric body composition metrics in predicting the risk of diabetes.

MATERIALS AND METHODS

This was a cross-sectional and 10-year retrospective longitudinal study. The cross-sectional analysis included health check-up data of 15,330 subjects with abdominal computed tomography (CT) images between January 1, 2011, and September 30, 2012. Of these, 10,570 subjects with available follow-up data were included in the longitudinal analyses. The volume of each body segment included in the abdominal CT images was measured using AI-based image analysis software.

RESULTS

Visceral fat (VF) proportion and VF/subcutaneous fat (SF) ratio increased with age, and both strongly predicted the presence and risk of developing diabetes. Optimal cut-offs for VF proportion were 24% for men and 16% for women, while VF/SF ratio values were 1.2 for men and 0.5 for women. The subjects with higher VF/SF ratio and VF proportion were associated with a greater risk of having diabetes (adjusted OR 2.0 [95% CI 1.7-2.4] in men; 2.9 [2.2-3.9] in women). In subjects with normal glucose tolerance, higher VF proportion and VF/SF ratio were associated with higher risk of developing prediabetes or diabetes (adjusted HR 1.3 [95% CI 1.1-1.4] in men; 1.4 [1.2-1.7] in women). These trends were consistently observed across each specified cut-off value.

CONCLUSIONS

AI-based volumetric analysis of abdominal CT images can be useful in obtaining body composition data and predicting the risk of diabetes.

The association of thyroid stimulating hormone and body fat in adults

BACKGROUND

Thyroid stimulating hormone (TSH) has been proven to be closely associated with metabolic abnormalities, including obesity. The objective of this investigation was to scrutinize the intricate association between TSH concentration and obesity, within the adult population. The study focused on a comprehensive examination of the relationship, delving into specific adiposity parameters such as total percent fat (TPF), android percent fat (APF), and gynoid percent fat (GPF).

METHODS

This study included 809 participants aged 20 and above with normal TSH values from the National Health and Nutrition Examination Survey (NHANES) 2007-2012. Multivariable linear regression models examined the associations of TSH concentration with TPF, APF, and GPF. Subgroup analyses, stratified by sex, were performed using multivariable linear regression. Fitted smoothing curves and generalized additive models addressed non-linear relationships between TSH and TPF, APF, and GPF.

RESULTS

In fully adjusted models, a significant positive association was observed between TPF and TSH (β = 0.01, 95% CI: 0.00-0.02, p<0.05), while no such association was evident in APF and GPF. Upon sex stratification, females exhibited significant positive correlations between TSH and TPF, APF, and GPF (all p < 0.001), contrasting with males where no such correlations were found. Notably, a non-linear association was identified in males, specifically a U-shaped curve (inflection point: 32.6%) for TSH and APF.

CONCLUSION

The study unveiled a statistically significant positive association between TSH and TPF in adults. Upon sex stratification, similar statistically significant relationships were observed between TSH and adiposity (TPF, APF, GPF) in females, while males exhibited a U-shaped non-linear relationship between TSH and APF.

Tissue-specific sex-dependent difference in the metabolism of fatty acid esters of hydroxy fatty acids

Fatty acid esters of hydroxy fatty acids (FAHFAs) are endogenous bioactive lipids known for their anti-inflammatory and anti-diabetic properties. Despite their therapeutic potential, little is known about the sex-specific variations in FAHFA metabolism. This study investigated the role of sex and Androgen Dependent TFPI Regulating Protein (ADTRP), a FAHFA hydrolase. Additionally, tissue-specific differences in FAHFA levels, focusing on the perigonadal white adipose tissue (pgWAT), subcutaneous white adipose tissue (scWAT), brown adipose tissue (BAT), plasma, and liver, were evaluated using metabolomics and lipidomics. We found that female mice exhibited higher FAHFA levels in pgWAT, scWAT, and BAT compared to males. FAHFA levels were inversely related to testosterone and Adtrp mRNA, which showed significantly lower expression in females compared with males in pgWAT and scWAT. However, no significant differences between the sexes were observed in plasma and liver FAHFA levels. Adtrp deletion had minimal impact on both sexes' metabolome and lipidome of pgWAT. However, we discovered higher endogenous levels of triacylglycerol estolides containing FAHFAs, a FAHFA metabolic reservoir, in the pgWAT of female mice. These findings suggest that sex-dependent differences in FAHFA levels occur primarily in specific WAT depots and may modulate local insulin sensitivity in adipocytes, and the role of ADTRP is limited to adipose depots. However, further investigations are warranted to fully comprehend the underlying mechanisms and implications of sex-dependent regulation of human FAHFA metabolism.

Quantitative assessment of morphological changes in lipid droplets and lipid-mito interactions with aging in brown adipose

The physical characteristics of brown adipose tissue (BAT) are defined by the presence of multilocular lipid droplets (LDs) within the brown adipocytes and a high abundance of iron-containing mitochondria, which give it its characteristic color. Normal mitochondrial function is, in part, regulated by organelle-to-organelle contacts. For example, the contact sites that mediate mitochondria-LD interactions are thought to have various physiological roles, such as the synthesis and metabolism of lipids. Aging is associated with mitochondrial dysfunction, and previous studies show that there are changes in mitochondrial structure and the proteins that modulate organelle contact sites. However, how mitochondria-LD interactions change with aging has yet to be fully clarified. Therefore, we sought to define age-related changes in LD morphology and mitochondria-lipid interactions in BAT. We examined the three-dimensional morphology of mitochondria and LDs in young (3-month) and aged (2-year) murine BAT using serial block face-scanning electron microscopy and the Amira program for segmentation, analysis, and quantification. Our analyses showed reductions in LD volume, area, and perimeter in aged samples in comparison to young samples. Additionally, we observed changes in LD appearance and type in aged samples compared to young samples. Notably, we found differences in mitochondrial interactions with LDs, which could implicate that these contacts may be important for energetics in aging. Upon further investigation, we also found changes in mitochondrial and cristae structure for the mitochondria interacting with LDs. Overall, these data define the nature of LD morphology and organelle-organelle contacts during aging and provide insight into LD contact site changes that interconnect biogerontology with mitochondrial function, metabolism, and bioactivity in aged BAT.

Cxcr4 regulates a pool of adipocyte progenitors and contributes to adiposity in a sex-dependent manner

Sex steroids modulate the distribution of mammalian white adipose tissues. Moreover, WAT remodeling requires adipocyte progenitor cells. Nevertheless, the sex-dependent mechanisms regulating adipocyte progenitors remain undetermined. Here, we uncover Cxcr4 acting in a sexually dimorphic manner to affect a pool of proliferating cells leading to restriction of female fat mass. We find that deletion of Cxcr4 in Pparγ-expressing cells results in female, not male, lipodystrophy, which cannot be restored by high-fat diet consumption. Additionally, Cxcr4 deletion is associated with a loss of a pool of proliferating adipocyte progenitors. Cxcr4 loss is accompanied by the upregulation of estrogen receptor alpha in adipose-derived PPARγ-labelled cells related to estradiol hypersensitivity and stalled adipogenesis. Estrogen removal or administration of antiestrogens restores WAT accumulation and dynamics of adipose-derived cells in Cxcr4-deficient mice. These findings implicate Cxcr4 as a female adipogenic rheostat, which may inform strategies to target female adiposity.

Dual Regulation Mechanism of Obesity: DNA Methylation and Intestinal Flora

Obesity is a multifactorial chronic inflammatory metabolic disorder, with pathogenesis influenced by genetic and non-genetic factors such as environment and diet. Intestinal microbes and their metabolites play significant roles in the occurrence and development of obesity by regulating energy metabolism, inducing chronic inflammation, and impacting intestinal hormone secretion. Epigenetics, which involves the regulation of host gene expression without changing the nucleotide sequence, provides an exact direction for us to understand how the environment, lifestyle factors, and other risk factors contribute to obesity. DNA methylation, as the most common epigenetic modification, is involved in the pathogenesis of various metabolic diseases. The epigenetic modification of the host is induced or regulated by the intestinal microbiota and their metabolites, linking the dynamic interaction between the microbiota and the host genome. In this review, we examined recent advancements in research, focusing on the involvement of intestinal microbiota and DNA methylation in the etiology and progression of obesity, as well as potential interactions between the two factors, providing novel perspectives and avenues for further elucidating the pathogenesis, prevention, and treatment of obesity.

The association between waist-to-hip ratio (WHR) with diabetes in the PERSIAN Guilan cohort study population

BACKGROUND

Waist circumference (WC), or waist-to-hip ratio (WHR), potentially offers a more accurate reflection of intra-abdominal fat accumulation and could serve as a superior predictor of type 2 diabetes mellitus (T2DM) risk compared to BMI. The current study investigated the relationship between WHR and its influencing factors among diabetes patients enrolled in the Prospective Epidemiological Research Studies in Iran (PERSIAN) Guilan Cohort study (PGCS).

METHOD

In this cross-sectional study of 10,520 participants, 2,531 had T2DM. Waist and hip circumference, body mass index (BMI), underlying diseases, and demographical data of participants were recorded. Also, fasting blood sugar (FBS), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides (TG) were assessed. All data was analyzed using SPSS version 16; the significant level was < 0.05.

RESULTS

The mean age of participants was 51.52 ± 8.90 years, and 39.9% had a BMI between 25 and 30 kg/m2. The prevalence of diabetes was 24.1% (n = 2531). About 7628 (72.5%) individuals had abnormal WHR, and 2072 (19.7%) were diabetics. Among patients with diabetes, abnormal WHR was significantly associated with age over 50, female gender, higher BMI, and lower LDL (P < 0.05).

CONCLUSION

The study showed a higher prevalence of abnormal WHR in diabetic patients. Abnormal WHR in patients with diabetes was significantly associated with age, gender, and BMI.

Sex- and Gender-Related Differences in Obesity: From Pathophysiological Mechanisms to Clinical Implications

Obesity, primarily characterized by excessive fat accumulation, is a multifactorial chronic disease with an increasing global prevalence. Despite the well-documented epidemiology and significant advances in understanding its pathophysiology and clinical implications, the impact of sex is typically overlooked in obesity research. Worldwide, women have a higher likelihood to become obese compared to men. Although women are offered weight loss interventions more often and at earlier stages than men, they are more vulnerable to psychopathology. Men, on the other hand, are less likely to pursue weight loss intervention and are more susceptible to the metabolic implications of obesity. In this narrative review, we comprehensively explored sex- and gender-specific differences in the development of obesity, focusing on a variety of biological variables, such as body composition, fat distribution and energy partitioning, the impact of sex steroid hormones and gut microbiota diversity, chromosomal and genetic variables, and behavioural and sociocultural variables influencing obesity development in men and women. Sex differences in obesity-related comorbidities and varying effectiveness of different weight loss interventions are also extensively discussed.

Determinants of echocardiographic epicardial adipose tissue in a general middle-aged population - The Cardiovascular Risk in Young Finns Study

Epicardial adipose tissue (EAT) is the cardiac visceral fat depot proposed to play a role in the etiology of various cardiovascular disease outcomes. Little is known about EAT determinants in a general population. We examined cardiometabolic, dietary, lifestyle and socioeconomic determinants of echocardiograpghically measured EAT in early adulthood. Data on cardiometabolic, dietary, lifestyle and socioeconomic factors were collected from participants of the Cardiovascular Risk in Young Finns Study (YFS; N = 1667; age 34-49 years). EAT thickness was measured from parasternal long axis echocardiograms. Multivariable regression analysis was used to study potential EAT determinants. Possible effect modification of sex was addressed. Mean EAT thickness was 4.07 mm (95% CI 4.00-4.17). Multivariable analysis [β indicating percentage of change in EAT(mm) per one unit increase in determinant variable] indicated female sex (β = 11.0, P < 0.0001), type 2 diabetes (β = 14.0, P = 0.02), waist circumference (cm) (β = 0.38, P < 0.0001), systolic blood pressure (mmHg) (β = 0.18, P = 0.02) and red meat intake (g/day) (β = 0.02, P = 0.05) as EAT determinants. Sex-specific analysis revealed age (year) (β = 0.59, P = 0.01), alcohol intake (drinks/day) (β = 4.69, P = 0.006), heavy drinking (yes/no) (β = 30.4, P < 0.0001) as EAT determinants in women and fruit intake (g/day) (β = -1.0, P = 0.04) in men. In the YFS cohort, waist circumference, systolic blood pressure and red meat intake were directly associated with EAT among all participants. In women, age, alcohol intake, heavy drinking and type 2 diabetes associated directly with EAT, while an inverse association was observed between fruit intake and EAT in men.

Sexual dimorphism and the multi-omic response to exercise training in rat subcutaneous white adipose tissue

Subcutaneous white adipose tissue (scWAT) is a dynamic storage and secretory organ that regulates systemic homeostasis, yet the impact of endurance exercise training (ExT) and sex on its molecular landscape is not fully established. Utilizing an integrative multi-omics approach, and leveraging data generated by the Molecular Transducers of Physical Activity Consortium (MoTrPAC), we show profound sexual dimorphism in the scWAT of sedentary rats and in the dynamic response of this tissue to ExT. Specifically, the scWAT of sedentary females displays -omic signatures related to insulin signaling and adipogenesis, whereas the scWAT of sedentary males is enriched in terms related to aerobic metabolism. These sex-specific -omic signatures are preserved or amplified with ExT. Integration of multi-omic analyses with phenotypic measures identifies molecular hubs predicted to drive sexually distinct responses to training. Overall, this study underscores the powerful impact of sex on adipose tissue biology and provides a rich resource to investigate the scWAT response to ExT.

The pathophysiology of visceral adipose tissues in cardiometabolic diseases

Central pattern of fat distribution, especially fat accumulation within the intraabdominal cavity increases risks for cardiometabolic diseases. Portal hypothesis combined with a pathological remodeling in visceral fat is considered the major etiological factor explaining the independent contribution of visceral obesity to cardiometabolic diseases. Excessive remodeling in visceral fat during development of obesity leads to dysfunctions in the depot, characterized by hypertrophy and death of adipocytes, hypoxia, inflammation, and fibrosis. Dysfunctional visceral fat secretes elevated levels of fatty acids, glycerol, and proinflammatory and profibrotic cytokines into the portal vein directly impacting the liver, the central regulator of systemic metabolism. These metabolic and endocrine products induce ectopic fat accumulation, insulin resistance, inflammation, and fibrosis in the liver, which in turn causes or exacerbates systemic metabolic derangements. Elucidation of underlying mechanisms that lead to the pathological remodeling and higher degree of dysfunctions in visceral adipose tissue is therefore, critical for the development of therapeutics to prevent deleterious sequelae in obesity. We review depot differences in metabolic and endocrine properties and expendabilities as well as underlying mechanisms that contribute to the pathophysiological aspects of visceral adiposity in cardiometabolic diseases. We also discuss impacts of different weight loss interventions on visceral adiposity and cardiometabolic diseases.

Tissue-specific sex difference in the metabolism of fatty acid esters of hydroxy fatty acids

Fatty acid esters of hydroxy fatty acids (FAHFAs) are endogenous bioactive lipids known for their anti-inflammatory and anti-diabetic properties. Despite their therapeutic potential, little is known about the sex-specific variations in FAHFA metabolism. This study investigated the role of Androgen Dependent TFPI Regulating Protein (ADTRP), a FAHFA hydrolase. Additionally, tissue-specific differences in FAHFA levels, focusing on the perigonadal white adipose tissue (pgWAT), subcutaneous white adipose tissue (scWAT), brown adipose tissue (BAT), plasma, and liver, were evaluated using metabolomics and lipidomics. We found that female mice exhibited higher FAHFA levels in pgWAT, scWAT, and BAT compared to males. FAHFA levels were inversely related to Adtrp mRNA, which showed significantly lower expression in females compared with males in pgWAT and scWAT. However, no significant differences between the sexes were observed in plasma and liver FAHFA levels. Adtrp deletion had minimal impact on both sexes' metabolome and lipidome of pgWAT. However, we discovered higher endogenous levels of triacylglycerol estolides containing FAHFAs, a FAHFA metabolic reservoir, in the pgWAT of female mice. These findings suggest that sex-dependent differences in FAHFA levels occur primarily in specific WAT depots and may modulate local insulin sensitivity in adipocytes. However, further investigations are warranted to fully comprehend the underlying mechanisms and implications of sex effects on FAHFA metabolism in humans.

An overview on androgen-mediated actions in skeletal muscle and adipose tissue

Androgens are a class of steroid hormones primarily associated with male sexual development and physiology, but exert pleiotropic effects in either sex. They have a crucial role in various physiological processes, including the regulation of skeletal muscle and adipose tissue homeostasis. The effects of androgens are mainly mediated through the androgen receptor (AR), a ligand-activated nuclear receptor expressed in both tissues. In skeletal muscle, androgens via AR exert a multitude of effects, ranging from increased muscle mass and strength, to the regulation of muscle fiber type composition, contraction and metabolic functions. In adipose tissue, androgens influence several processes including proliferation, fat distribution, and metabolism but they display depot-specific and organism-specific effects which differ in certain context. This review further explores the potential mechanisms underlying androgen-AR signaling in skeletal muscle and adipose tissue. Understanding the roles of androgens and their receptor in skeletal muscle and adipose tissue is essential for elucidating their contributions to physiological processes, disease conditions, and potential therapeutic interventions.

Retrospective analysis of high-intensity focused electromagnetic procedure synchronized with radiofrequency energy for visceral fat reduction

BACKGROUND

Visceral adipose tissue (VAT), present in the abdominal cavity, oftentimes contributes to an unpleasant aesthetic appearance and can be correlated with serious health issues. High-intensity focused electromagnetic field (HIFEM) technology with synchronized radiofrequency (RF) was recently used for abdominal body shaping through subcutaneous fat reduction and muscle growth.

AIM

This study aimed to assess the effect of HIFEM + RF technology on VAT tissue.

METHODS

Data of 16 men and 24 women (22-62 years, 21.2-34.3 kg/cm2 ) from the original study were retrospectively reviewed. All subjects received three 30-min HIFEM + RF abdominal treatments once weekly for three consecutive weeks. The VAT area was measured in the axial plane of MRI scans at two levels: L4-L5 vertebrae and 5 cm above this level. The VAT was identified, segmented, and calculated, yielding total area in square centimeters per scan at both specified levels.

RESULTS

By thoughtful review of the subject's post-treatment MRI scans, no other changes in the abdominal cavity were found except for VAT. The evaluation showed a VAT reduction of 17.8% (p < 0.001) on average at 3-month follow-up, maintaining the results up to 6 months (-17.3%). Averaging the values obtained from both measured levels, the VAT, occupied an area of 100.2 ± 73.3 cm2 at the baseline. At the 3-month follow-up, the subjects achieved an average reduction of 17.9 cm2 , preserving the results at 6 months (-17.6 ± 17.3 cm).

CONCLUSION

This retrospective analysis of MRI images objectively documented the effect of HIFEM + RF abdominal therapy on VAT. The data indicates considerable VAT reduction without serious adverse events following the HIFEM + RF procedure.

Centile reference curves of the ultrasound-based characteristics of the rectus femoris muscle composition in children at 4-11 years old

Quantitative diagnostic ultrasound has been proposed as a way to characterize muscle structure, but there is a lack of normative data for children. This study aims to establish age-specific normal ranges for echo-intensity (EI), cross-sectional area (CSA), muscular thickness (MT), and subcutaneous adipose thickness (SAT) values of the rectus femoris muscle in typically developing children. The study recruited 497 children (288 boys and 209 girls) aged 4-10.9 years (mean age 7.39 years), and muscle parameters were measured using 2D B-mode ultrasound. Percentile values and reference curves were calculated using the Lambda, Mu, and Sigma method (LMS). The results showed small variation between measurements for boys compared to girls, with the most significant difference in EI, CSA, and MT values. EI decreased with age, with the most pronounced curve in boys. SAT increased in both sexes, with a slightly higher increase in girls after the age of 9.0 years. This study provides the first age-specific reference norms for the rectus femoris muscle architecture in children, and further research is needed to validate these curves and determine their clinical utility.

Pharmacological antagonism of receptor for advanced glycation end products signaling promotes thermogenesis, healthful body mass and composition, and metabolism in mice

OBJECTIVE

Optimal body mass and composition as well as metabolic fitness require tightly regulated and interconnected mechanisms across tissues. Disturbances in these regulatory networks tip the balance between metabolic health versus overweight and obesity and their complications. The authors previously demonstrated roles for the receptor for advanced glycation end products (RAGE) in obesity, as global- or adipocyte-specific deletion of Ager (the gene encoding RAGE) protected mice from high-fat diet-induced obesity and metabolic dysfunction.

METHODS

To explore translational strategies evoked by these observations, a small molecule antagonist of RAGE signaling, RAGE229, was administered to lean mice and mice with obesity undergoing diet-induced weight loss. Body mass and composition and whole body and adipose tissue metabolism were examined.

RESULTS

This study demonstrates that antagonism of RAGE signaling reduced body mass and adiposity and improved glucose, insulin, and lipid metabolism in lean male and female mice and in male mice with obesity undergoing weight loss. In adipose tissue and in human and mouse adipocytes, RAGE229 enhanced phosphorylation of protein kinase A substrates, which augmented lipolysis, mitochondrial function, and thermogenic programs.

CONCLUSIONS

Pharmacological antagonism of RAGE signaling is a potent strategy to optimize healthful body mass and composition and metabolic fitness.

Evaluation of ultrasonographic approaches aimed at determining distinct abdominal adipose tissue depots

Objective

To analyze different anatomical sites in the abdominal region, in order to determine the positional parameter that identifies a higher level of visceral adipose tissue (VAT) and confers a greater cardiometabolic risk.

Materials and methods

This is a methodological study in which VAT was evaluated by ultrasonography (USG) in three anatomical sites in the abdomen, while the abdominal circumference (AC) was measured using seven different protocols. Additionally, the glycemic and lipid profile, C-reactive protein, and the presence of systemic arterial hypertension were evaluated.

Results

One hundred and six individuals with an average age of 42 (36.8-46.2) years were included. The evaluation of the calibration of the ultrasound procedure for the analysis of VAT by intra- and inter-evaluators showed high reproducibility. The pattern of abdominal fat distribution differed between sexes, with higher mean VAT in males (p < 0.05) and higher mean SAT (subcutaneous adipose tissue) in females (p < 0.005). In the abdominal scan applied to women, higher levels of VAT and lower levels of SAT were observed in the narrower waist region, between the iliac crest and the last rib (p < 0.001). In males, the profile of adipose disposition along the abdomen was uniform (p > 0.05). Correlations between VAT measured by USG and cardiometabolic parameters were relatively stronger in the upper abdomen (p < 0.05).

Conclusion

Women accumulate more VAT in the narrower waist region, while men accumulate VAT uniformly across the abdomen. There was relative superiority in predicting cardiometabolic risk in the upper abdomen for both sexes.

Occupational differences in personal care product use and urinary concentration of endocrine disrupting chemicals by gender

BACKGROUND

In most societies, women and men systematically differ in consumption of cosmetics and household products, which are interlinked with gendered norms and occupational segregation. We investigated the differences in personal care product (PCP) use and exposure to endocrine disrupting chemicals (EDCs) based on occupation and gender.

METHODS

We utilized data from the first to third Korean National Environmental Health Survey analyzing 9218 participants aged 20-59 years engaged in their current occupation for ≥3 months. Frequent PCP use (≥once/week) and exposure to EDCs were analyzed by gender and occupation. We used least-square geometric means (LSGMs) of urinary concentrations of the five EDCs adjusted for covariates.

RESULTS

Manual occupation was most common in men and no paid occupation was most frequent in women. In general, clerical, service, and sales workers showed the highest prevalence of frequent use of hair and body products. Women used body and makeup products more frequently than men. For all five EDCs, similarly, women showed higher urinary levels in all occupation groups. When stratified by gender, the differences in urinary concentration of EDCs across occupation groups were not observed in men. Among women, clerical, service, and sales workers showed higher bisphenol A (BPA) and mono-n-butyl phthalate (MnBP) levels than manual workers.

CONCLUSIONS

Differentials in exposure to EDCs by occupation groups were not evident for men. Given the higher urinary concentration of EDCs in women compared to men, interventions to reduce the exposure to EDCs would need to focus on women, especially in clerical, service, and sales occupations.

Sexual dimorphism and the multi-omic response to exercise training in rat subcutaneous white adipose tissue

Subcutaneous white adipose tissue (scWAT) is a dynamic storage and secretory organ that regulates systemic homeostasis, yet the impact of endurance exercise training and sex on its molecular landscape has not been fully established. Utilizing an integrative multi-omics approach with data generated by the Molecular Transducers of Physical Activity Consortium (MoTrPAC), we identified profound sexual dimorphism in the dynamic response of rat scWAT to endurance exercise training. Despite similar cardiorespiratory improvements, only male rats reduced whole-body adiposity, scWAT adipocyte size, and total scWAT triglyceride abundance with training. Multi-omic analyses of adipose tissue integrated with phenotypic measures identified sex-specific training responses including enrichment of mTOR signaling in females, while males displayed enhanced mitochondrial ribosome biogenesis and oxidative metabolism. Overall, this study reinforces our understanding that sex impacts scWAT biology and provides a rich resource to interrogate responses of scWAT to endurance training.

Zinc and Zinc Transporters in Dermatology

Zinc is an important trace mineral in the human body and a daily intake of zinc is required to maintain a healthy status. Over the past decades, zinc has been used in formulating topical and systemic therapies for various skin disorders owing to its wound healing and antimicrobial properties. Zinc transporters play a major role in maintaining the integrity of the integumentary system by controlling zinc homeostasis within dermal layers. Mutations and abnormal function of zinc-transporting proteins can lead to disease development, such as spondylocheirodysplastic Ehlers-Danlos syndrome (SCD-EDS) and acrodermatitis enteropathica (AE) which can be fatal if left untreated. This review discusses the layers of the skin, the importance of zinc and zinc transporters in each layer, and the various skin disorders caused by zinc deficiency, in addition to zinc-containing compounds used for treating different skin disorders and skin protection.

Differences in Adipose Gene Expression Profiles between Male and Female Even Reindeer (Rangifer tarandus) in Sakha (Yakutia)

Reindeer are native to harsh northern Eurasian environments which are characterized by long and cold winters, short summers, and limited pasture vegetation. Adipose tissues play a significant role in these animals by modulating energy metabolism, immunity, and reproduction. Here, we have investigated the transcriptome profiles of metacarpal, perirenal, and prescapular adipose tissues in Even reindeer and searched for genes that were differentially expressed in male and female individuals. A total of 15,551 genes were expressed, where the transcriptome profile of metacarpal adipose tissue was found to be distinct from that of perirenal and prescapular adipose tissues. Interestingly, 10 genes, including PRDM9, which is known to have an important role in adaptation and speciation in reindeer, were always upregulated in all three tissues of male reindeer.

The Regulation of Adipose Tissue Health by Estrogens

Obesity and its' associated metabolic diseases such as type 2 diabetes and cardiometabolic disorders are significant health problems confronting many countries. A major driver for developing obesity and metabolic dysfunction is the uncontrolled expansion of white adipose tissue (WAT). Specifically, the pathophysiological expansion of visceral WAT is often associated with metabolic dysfunction due to changes in adipokine secretion profiles, reduced vascularization, increased fibrosis, and enrichment of pro-inflammatory immune cells. A critical determinate of body fat distribution and WAT health is the sex steroid estrogen. The bioavailability of estrogen appears to favor metabolically healthy subcutaneous fat over visceral fat growth while protecting against changes in metabolic dysfunction. Our review will focus on the role of estrogen on body fat partitioning, WAT homeostasis, adipogenesis, adipocyte progenitor cell (APC) function, and thermogenesis to control WAT health and systemic metabolism.

Prenatal exposure to persistent organic pollutants and childhood obesity: A systematic review and meta-analysis of human studies

We conducted a systematic review and meta-analysis of the associations between prenatal exposure to persistent organic pollutants (POPs) and childhood obesity. We focused on organochlorines (dichlorodiphenyltrichloroethane [DDT], dichlorodiphenyldichloroethylene [DDE], hexachlorobenzene [HCB], and polychlorinated biphenyls [PCBs]), perfluoroalkyl and polyfluoroalkyl substances (PFAS), and polybrominated diphenyl ethers (PBDEs) that are the POPs more widely studied in environmental birth cohorts so far. We search two databases (PubMed and Embase) through July/09/2021 and identified 33 studies reporting associations with prenatal organochlorine exposure, 21 studies reporting associations with prenatal PFAS, and five studies reporting associations with prenatal PBDEs. We conducted a qualitative review. Additionally, we performed random-effects meta-analyses of POP exposures, with data estimates from at least three prospective studies, and BMI-z. Prenatal DDE and HCB levels were associated with higher BMI z-score in childhood (beta: 0.12, 95% CI: 0.03, 0.21; I2 : 28.1% per study-specific log increase of DDE and beta: 0.31, 95% CI: 0.09, 0.53; I2 : 31.9% per study-specific log increase of HCB). No significant associations between PCB-153, PFOA, PFOS, or pentaPBDEs with childhood BMI were found in meta-analyses. In individual studies, there was inconclusive evidence that POP levels were positively associated with other obesity indicators (e.g., waist circumference).

The value of sex-specific abdominal visceral fat as measured via CT as a predictor of clear renal cell carcinoma T stage

Although much is known about how adipose tissue affects the development of clear cell renal carcinoma (ccRCC), little information is available for the utility of sex-specific abdominal visceral fat composition as a predictor of clear cell renal carcinoma (ccRCC) T stage. We conducted CT-based sex-specific abdominal fat measurements in ccRCC patients to assess whether VFA distribution could predict the ccRCC T stage. In total, 253 patients (182 males and 71 females) from our hospital with pathologically confirmed ccRCC (178 low T-stage and 75 high T-stage) were retrospectively reviewed for the present study. Computed tomography (CT) scans were assessed using ImageJ to differentiate between the visceral and subcutaneous fat areas (VFA and SFA), after which the relative VFA (rVFA) and total fat area (TFA) were computed. The relationships between these fat area-related variables, patient age, sex, and BMI, and ccRCC T stage were then evaluated through univariate and multivariate logistic regression analysis to clarify the association between general or sex-specific abdominal visceral fat and T stage. Following adjustment for age, males with high T stage ccRCC exhibited an increased rVFA as compared to males with low T stage ccRCC, with the same relationship being observed among females. This association between rVFA and high T stage was confirmed through both univariate and multivariate models. As thus, sex-specific visceral fat composition is a reliable independent predictor that can identify both male and female patients with high T stage ccRCC.

Gender difference in the relationship between lipid accumulation product index and pulse pressure in nondiabetic Korean adults: The Korean National Health and Nutrition Examination Survey 2013-2014

The present study was conducted to assess the association between the lipid accumulation product index (LAP) and pulse pressure (PP) by gender in nondiabetic Korean adults. This study used the data of 8,240 nondiabetic adults (3,577 men and 4,663 women) aged ≥ 20 years from the Korean National Health and Nutrition Examination Survey 2013-2014. Key findings from the study were as follows: first, the mean values of age for the overall population, men, and women were 49.59 ± 15.73 years, 49.26 ± 16.04 years, and 49.85 ± 15.47 years, respectively. Second, in women (n = 4,663), after adjustment for related variables and with quartile 1 of LAP as a reference, the odds ratios (ORs) of high PP (PP > 60 mmHg) were significantly higher in quartile 3 [1.735 (95% confidence interval [CI], 1.064-2.831)] and quartile 4 of LAP [2.271 (95% CI, 1.325-3.893)]. Third, high PP in men (n = 3,577) was not associated with the quartiles of LAP. Forth, after adjustment for related variables, the PP level was positively associated with the quartiles of LAP in women (p < .001) but not in men (p = .400). PP was positively associated with LAP in nondiabetic Korean women but not in men.

The Metabolic Significance of Intermuscular Adipose Tissue: Is IMAT a Friend or a Foe to Metabolic Health?

Adipose tissues are not homogeneous and show site-specific properties. An elusive and understudied adipose tissue depot, most likely due to its limited accessibility, is the intermuscular adipose tissue (IMAT) depot. Adipose tissue is a pliable organ with the ability to adapt to its physiological context, yet whether that adaptation is harmful or beneficial in the IMAT depot remains to be explored in humans. Potential reasons for IMAT accumulation in humans being deleterious or beneficial include 1) sex and related circulating hormone levels, 2) race and ethnicity, and 3) lifestyle factors (e.g., diet and physical activity level). IMAT quantity per se may not be the driving factor in the etiology of insulin resistance and type 2 diabetes, but rather the quality of the IMAT itself is the true puppeteer. Adipose tissue quality likely influences its secreted factors, which are also likely to influence metabolism of surrounding tissues. The advent of molecular assessments such as transcriptome sequencing (RNAseq), assay for transposase-accessible chromatin using sequencing (ATACseq), and DNA methylation at the single-cell and single-nucleus levels, as well as the potential for ultrasound-guided biopsies specifically for IMAT, will permit more sophisticated investigations of human IMAT and dramatically advance our understanding of this enigmatic adipose tissue.

Association between visceral/subcutaneous adipose tissue ratio and plasma inflammatory markers and score for cardiovascular risk prediction in a Brazilian cohort: Pró-Saúde Study

Visceral adipose tissue (VAT) is associated with various metabolic disorders, and adipokines, secreted by adipose tissue, are involved in their pathogenesis. This study investigated associations between VAT/subcutaneous adipose tissue (SAT) ratio, inflammatory markers, and cardiovascular (CV) risk-score in adults. Plasma levels of adipokines, plasma lipid profile, blood pressure, and body composition (using dual-emission x-ray absorptiometry) were determined. CV risk-score based on the American College of Cardiology and the American Heart Association (ACC/AHA) score was calculated in a sample of 309 Brazilian civil servants aged <60 years. Participants' VAT/SAT ratio were categorized into quartiles. Among males, plasma leptin (2.8 ng/mL) and C reactive protein (CRP) (0.2 mg/dL) (P<0.05) levels were higher at P75 and P50 than P5, and the highest calculated CV risk-score was observed at P75 (7.1%). Among females, higher plasma adiponectin levels were observed at P25 (54.3 ng/mL) compared with P75 (36 ng/mL) (P<0.05). Higher plasma CRP levels were observed at P75 (0.4 mg/dL) compared with P5 (0.1 mg/dL) (P<0.05). Higher CV risk-score was observed at P75 (2.0%) compared with P5 (0.7%). In both sexes, VAT and VAT/SAT ratio were directly associated with plasma leptin, CRP, and CV risk-score, and inversely associated with adiponectin; SAT was directly associated with plasma leptin and CRP (P<0.01); interleukin (IL)-10 and CRP were directly associated with adiponectin and leptin, respectively (P<0.05). Among men only, IL-10 (inversely) and CRP (directly) were associated with CV risk-score (P=0.02). Our results strengthened the relevance of the VAT/SAT ratio in cardiovascular risk.

Sex differences in brown adipose tissue activity and cold-induced thermogenesis

INTRODUCTION

Brown adipose tissue (BAT) is suggested to exhibit a sexual dimorphism and thus contributes to the observed sex differences in cardiometabolic risk observed between women and men. Clinical data supporting this hypothesis are however scarce. The aim of this study was to investigate the relationship between BAT activity and sex using positron emission tomography (PET) - the current gold-standard for BAT quantification.

METHODS

In this study, we included 95 subjects with a wide BMI range (20-55 kg/m²) aged from 18 to 50 years. Avoiding shivering, participants were cooled with a water-perfused vest to achieve adequate BAT activation. BAT activity was determined by ¹⁸F-fluorodeoxyglucose PET/computed tomography (¹⁸F-FDG PET/CT). Cold-induced thermogenesis (CIT) was quantified by indirect calorimetry.

RESULTS

BAT was present in 44.6% of pre-menopausal women and in 35.9% of men (p = 0.394). CIT was significantly higher in women (p = 0.024). Estradiol levels were positively associated with CIT independent of age, sex, body fat and other sex hormones (b = 0.360, p = 0.016). In women, CIT decreased during the menstrual cycle, with lower levels in the luteal phase similar to median concentrations in men.

CONCLUSION

The prevalence of cold-activated BAT is slightly but non-significantly higher in pre-menopausal women than men. CIT is increased in females and independently associated with estradiol, suggesting that sex hormones may play a role in different thermogenic responses between men and women.

Recent Update on the Molecular Mechanisms of Gonadal Steroids Action in Adipose Tissue

The gonadal steroids, including androgens, estrogens and progestogens, are involved in the control of body fat distribution in humans. Nevertheless, not only the size and localization of the fat depots depend on the sex steroids levels, but they can also highly affect the functioning of adipose tissue. Namely, the gonadocorticoids can directly influence insulin signaling, lipid metabolism, fatty acid uptake and adipokine production. They may also alter energy balance and glucose homeostasis in adipocytes in an indirect way, e.g., by changing the expression level of aquaglyceroporins. This work presents the recent advances in understanding the molecular mechanism of how the gonadal steroids influence the functioning of adipose tissue leading to a set of detrimental metabolic consequences. Special attention is given here to highlighting the sexual dimorphism of adipocyte functioning in terms of health and disease. Particularly, we discuss the molecular background of metabolic disturbances occurring in consequence of hormonal imbalance which is characteristic of some common endocrinopathies such as the polycystic ovary syndrome. From this perspective, we highlight the potential drug targets and the active substances which can be used in personalized sex-specific management of metabolic diseases, in accord with the patient's hormonal status.

Obesity, Adipose Tissue and Vascular Dysfunction

Cardiovascular diseases are the leading cause of death worldwide. Overweight and obesity are strongly associated with comorbidities such as hypertension and insulin resistance, which collectively contribute to the development of cardiovascular diseases and resultant morbidity and mortality. Forty-two percent of adults in the United States are obese, and a total of 1.9 billion adults worldwide are overweight or obese. These alarming numbers, which continue to climb, represent a major health and economic burden. Adipose tissue is a highly dynamic organ that can be classified based on the cellular composition of different depots and their distinct anatomical localization. Massive expansion and remodeling of adipose tissue during obesity differentially affects specific adipose tissue depots and significantly contributes to vascular dysfunction and cardiovascular diseases. Visceral adipose tissue accumulation results in increased immune cell infiltration and secretion of vasoconstrictor mediators, whereas expansion of subcutaneous adipose tissue is less harmful. Therefore, fat distribution more than overall body weight is a key determinant of the risk for cardiovascular diseases. Thermogenic brown and beige adipose tissue, in contrast to white adipose tissue, is associated with beneficial effects on the vasculature. The relationship between the type of adipose tissue and its influence on vascular function becomes particularly evident in the context of the heterogenous phenotype of perivascular adipose tissue that is strongly location dependent. In this review, we address the abnormal remodeling of specific adipose tissue depots during obesity and how this critically contributes to the development of hypertension, endothelial dysfunction, and vascular stiffness. We also discuss the local and systemic roles of adipose tissue derived secreted factors and increased systemic inflammation during obesity and highlight their detrimental impact on cardiovascular health.

Adipose Tissue Gene Expression of Entire Male, Immunocastrated and Surgically Castrated Pigs

Differences in adipose tissue deposition and properties between pig male sex categories, i.e., entire males (EM), immunocastrates (IC) and surgical castrates (SC) are relatively well-characterized, whereas the underlying molecular mechanisms are still not fully understood. To gain knowledge about the genetic regulation of the differences in adipose tissue deposition, two different approaches were used: RNA-sequencing and candidate gene expression by quantitative PCR. A total of 83 differentially expressed genes were identified between EM and IC, 15 between IC and SC and 48 between EM and SC by RNA-sequencing of the subcutaneous adipose tissue. Comparing EM with IC or SC, upregulated genes related to extracellular matrix dynamics and adipogenesis, and downregulated genes involved in the control of lipid and carbohydrate metabolism were detected. Differential gene expression generally indicated high similarity between IC and SC as opposed to EM, except for several heat shock protein genes that were upregulated in EM and IC compared with SC. The candidate gene expression approach showed that genes involved in lipogenesis were downregulated in EM compared with IC pigs, further confirming RNA-sequencing results.

Sexual dimorphism in adipose tissue mitochondrial function and metabolic flexibility in obesity

OBJECTIVE

The prevalence of obesity is growing globally. Adiposity increases the risk for metabolic syndrome, type 2 diabetes and cardiovascular disease. Adipose tissue distribution influences systemic metabolism and impacts metabolic disease risk. The link between sexual dimorphisms of adiposity and metabolism is poorly defined. We hypothesise that depot-specific adipose tissue mitochondrial function contributes to the sexual dimorphism of metabolic flexibility in obesity.

METHODS

Male and female mice fed high fat diet (HFD) or standard diet (STD) from 8-18 weeks of age underwent whole animal calorimetry and high-resolution mitochondrial respirometry analysis on adipose tissue depots. To determine translatability we used RT-qPCR to examine key brown adipocyte-associated gene expression: peroxisome proliferator-activated receptor co-activator 1α, Uncoupling protein 1 and cell death inducing DFFA like effector a in brown adipose tissue (BAT) and subcutaneous adipose tissue (sWAT) of 18-week-old mice and sWAT from human volunteers.

RESULTS

Male mice exhibited greater weight gain compared to female mice when challenged with HFD. Relative to increased body mass, the adipose to body weight ratio for BAT and sWAT depots was increased in HFD-fed males compared to female HFD-fed mice. Oxygen consumption, energy expenditure, respiratory exchange ratio and food consumption did not differ between males and females fed HFD. BAT mitochondria from obese females showed increased Complex I & II respiration and maximal respiration compared to lean females whereas obese males did not exhibit adaptive mitochondrial BAT respiration. Sexual dimorphism in BAT-associated gene expression in sWAT was also associated with Body Mass Index in humans.

CONCLUSIONS

We show that sexual dimorphism of weight gain is reflected in mitochondrial respiration analysis. Female mice have increased metabolic flexibility to adapt to changes in energy intake by regulating energy expenditure through increased complex II and maximal mitochondrial respiration within BAT when HFD challenged and increased proton leak in sWAT mitochondria.

Immuno-Endocrinology of COVID-19: The Key Role of Sex Hormones

Epidemiological evidence shows clear gender disparities in the Coronavirus 2019 Disease (COVID-19) severity and fatality. This may reflect the contribution of gender-related factors, such as sex hormones, to COVID-19 pathogenesis. However, the mechanism linking gender disparities to COVID-19 severity is still poorly understood. In this review, we will pinpoint several elements involved in COVID-19 pathogenesis that are regulated by the two main sex hormones, estrogen and androgen. These include tissue specific gene regulation of SARS-CoV2 entry factors, innate and adaptive immune responses to infection, immunometabolism, and susceptibility to tissue injury by cytopathic effect or hyper-inflammatory response. We will discuss the mechanistic link between sex hormone regulation of COVID-19 pathogenetic factors and disease severity. Finally, we will summarize current evidence from clinical studies and trials targeting sex hormones and their signalling in COVID-19. A better understanding of the role of sex hormones in COVID-19 may identify targets for therapeutic intervention and allow optimization of treatment outcomes towards gender-based personalised medicine.

High-fat diet-fed ovariectomized mice are susceptible to accelerated subcutaneous tumor growth potentially through adipose tissue inflammation, local insulin-like growth factor release, and tumor associated macrophages

Background: The association between obesity and colorectal cancer (CRC) risk has been well established. This relationship appears to be more significant in men than in women, which may be attributable to sex hormones. However, controlled animal studies to substantiate these claims and the mechanisms involved are lacking.

Materials and Methods: MC38 murine colon adenocarcinoma cells were injected subcutaneously into high-fat diet (HFD) fed male, female and ovariectomized (OVX) female C57BL/6 mice.

Results: HFD increased tumor growth (main effect) that was consistent with metabolic perturbations (P < 0.01). HFD OVX mice exhibited the most significant tumor growth compared to HFD male and female mice (p < 0.05) and this was associated with increased subcutaneous adipose tissue (p < 0.05). Further, the subcutaneous adipose tissue depots within HFD OVX mice exhibited more severe macrophage associated inflammation compared to female (P < 0.01), but not male mice. Conditioned media from subcutaneous adipose tissue of HFD OVX contained higher IGF-1 levels compared to male (P < 0.01), but not female mice. Finally, HFD OVX mice had increased M2-like gene expression in their tumor-associated macrophages (TAMs) compared to female mice (P < 0.01).

Conclusions: This work provides evidences suggesting adiposity, adipose specific IGF-1, macrophage associated adipose inflammation, and TAMs as potential mechanisms driving obesity-enhanced CRC in females lacking ovarian hormones.

Relationships of Physical Activity and Diet Quality with Body Composition and Fat Distribution in US Adults

OBJECTIVE

This study aimed to investigate the relationships among physical activity (PA), diet quality, body composition, and fat distribution in a representative sample of US adults.

METHODS

A cross-sectional analysis was conducted using publicly accessible data from the 2011 to 2016 National Health and Nutrition Examination Survey and the Food Patterns Equivalents Database (n = 7,423). Variables from the data sets were analyzed for this study, including PA, two 24-hour dietary recalls, and dual-energy x-ray absorptiometry outputs.

RESULTS

For men, PA and diet quality were inversely associated with the percentage of body fat (β = -0.0042, 95% CI: -0.0084 to -0.0001; β = -0.28, 95% CI: -0.42 to -0.14) and fat mass index (β = -0.0125, 95% CI: -0.0209 to -0.0041; β = -0.56, 95% CI: -0.81 to -0.32); meeting the PA recommendation and having good diet quality provided an additive effect on body fat. A similar pattern was observed in women. Additionally, diet quality was inversely associated with all fat distribution measures in both sexes, whereas PA was positively associated with lean mass measures in men only.

CONCLUSIONS

Increased PA and/or better diet quality were associated with reduced body fat, a healthier fat distribution, and increased lean mass. Further research examining how changes in PA or diet quality influence body composition and fat distribution in adults is warranted.

Adipose Morphology: a Critical Factor in Regulation of Human Metabolic Diseases and Adipose Tissue Dysfunction

Emerging evidence highlights that dysfunction of adipose tissue contributes to impaired insulin sensitivity and systemic metabolic deterioration in obese state. Of note, adipocyte hypertrophy serves as a critical event which associates closely with adipose dysfunction. An increase in cell size exacerbates hypoxia and inflammation as well as excessive collagen deposition, finally leading to metabolic dysregulation. Specific mechanisms of adipocyte hypertrophy include dysregulated differentiation and maturation of preadipocytes, enlargement of lipid droplets, and abnormal adipocyte osmolarity sensors. Also, weight loss therapies exert profound influence on adipocyte size. Here, we summarize the critical role of adipocyte hypertrophy in the development of metabolic disturbances. Future studies are required to establish a standard criterion of size measurement to better clarify the impact of adipocyte hypertrophy on changes in metabolic homeostasis.

Fasting and refeeding cycles alter subcutaneous white depot growth dynamics and the morphology of brown adipose tissue in female rats

Intermittent food restriction (IFR) is used mainly for weight loss; however, its effects on adipose tissue are not known when alternating with an obesogenic diet. To demonstrate its effects on morphological dynamics of fat deposits, female Wistar rats were distributed into groups: standard control (ST-C), with commercial diet; DIO control (DIO-C), with a diet that induces obesity (DIO) during the first and last 15 d, replaced by a standard diet for thirty intermediate days; standard restricted (ST-R), with standard diet during the first and last 15 d, with six cycles of IFR at 50 % of ST-C; and DIO restricted (DIO-R), in DIO during the first and last 15 d, with six cycles of IFR at 50 % of DIO-C. At 105 d of life, white adipose tissue (WAT) and brown adipose tissue (BAT) deposits were collected, weighed and histology performed. The DIO-R group showed higher total food intake (DIO-R 10 768·0 (SEM 357·52) kJ/g v. DIO-C 8868·6 (SEM 249·25) kJ/g, P < 0·0001), energy efficiency during RAI (DIO-R 2·26 (SEM 0·05) g/kJ v. DIO-C 0·70 (SEM 0·03) g/kJ, P < 0·0001) and WAT (DIO-R 5·65 (SEM 0·30) g/100 g v. DIO-C 4·56 (SEM 0·30) g/100 g) than their respective control. Furthermore, IFR groups presented hypertrophy of WAT and BAT, as well as fibrosis in BAT. Thus, IFR can establish prospective resistance to weight loss by favouring changes in adipose tissue morphology, increased energy intake and efficiency. Finally, the DIO diet before and after IFR aggravates the damages caused by the restriction.

Sex and Region-Specific Associations of Bone Mineral Content, Muscle Mass, and Fat Mass with Insulin Resistance

Background: To compare the strengths of the associations between total and region-specific body composition and insulin resistance (IR) considering sex and menopausal status and to compare body composition indicators for discriminating high IR. Materials and Methods: Among 5380 men, 3652 premenopausal women, and 3207 postmenopausal women in the Korean National Health and Nutrition Examination Survey, high IR was defined as the sex-specific highest quintiles of homeostasis model assessment IR and metabolic syndrome. Percentages of bone mineral content (BMC%), muscle mass (MM%), and fat mass (FM%) were measured for the whole body, trunk, and upper/lower extremities by dual-energy X-ray absorptiometry. Results: After adjusting for body mass, age, education, smoking status, alcohol use, and physical activity, one-standard deviation increases in whole-body FM%, MM%, and BMC% were associated with 50%-63%, 19%-26%, and 14%-22% higher odds of high IR in men and pre- and postmenopausal women, 31%-36%, 12%-17%, and 10%-15% lower odds, and 27%-36%, 31%-40%, and 19%-23% lower odds, respectively. Those associations for FM% in men and BMC% in premenopausal women tended to be stronger in the upper body than in lower extremities. In receiver operating characteristic curve analysis, FM% in men and BMC% in women had superior discriminatory abilities for high IR. Conclusions: IR may have a stronger association with FM% in men and BMC% in premenopausal women in upper body, while the association strength in postmenopausal women may be similar across body composition. These findings reveal differences in the strengths of region-, sex, and menopausal status-specific relationships between body composition and IR.

The omentum of obese girls harbors small adipocytes and browning transcripts

Severe obesity (SO) affects about 6% of youth in the United States, augmenting the risks for cardiovascular disease and type 2 diabetes. Herein, we obtained paired omental adipose tissue (omVAT) and abdominal subcutaneous adipose tissue (SAT) biopsies from girls with SO undergoing sleeve gastrectomy (SG), to test whether differences in cellular and transcriptomic profiles between omVAT and SAT depots affect insulin sensitivity differently. Following weight loss, these analyses were repeated in a subgroup of subjects having a second SAT biopsy. We found that omVAT displayed smaller adipocytes compared with SAT, increased lipolysis through adipose triglyceride lipase phosphorylation, reduced inflammation, and increased expression of browning/beiging markers. Contrary to omVAT, SAT adipocyte diameter correlated with insulin resistance. Following SG, both weight and insulin sensitivity improved markedly in all subjects. SAT adipocytes' size became smaller, showing increased lipolysis through perilipin 1 phosphorylation, decreased inflammation, and increased expression in browning/beiging markers. In summary, in adolescent girls with SO, both omVAT and SAT depots showed distinct cellular and transcriptomic profiles. Following weight loss, the SAT depot changed its cellular morphology and transcriptomic profiles into more favorable ones. These changes in the SAT depot may play a fundamental role in the resolution of insulin resistance.

Percent of body fat, fat-mass, fat-free mass and assessment of body composition among rural school-going children of Eastern-India

Percent of body fat (PBF), fat mass (FM) and fat free mass (FFM) are useful indicators for the assessment of body composition. The present study was conducted among 1351 children (boys: 660; girls: 691) aged 5–12 years residing in West Bengal, Eastern-India. The children were selected using a stratified random sampling method. Anthropometric measurements of height, weight, triceps skinfold (TSF) and sub-scapular skinfold (SSF) were recorded using standard procedures. The PBF, PBF-for-age z-score (PBFZ) and body mass index (BMI) were subsequently calculated. Body composition was assessed using FM, FFM, fat mass index (FMI) and fat free mass index (FFMI). Age-specific mean values of FM ranged from 2.12–4.00 kg (boys) and 2.16–4.40 kg (girls). Age-specific mean values of FFM ranged from 14.45–23.93 kg (boys) and 14.01–23.03 kg (girls). Sex-specific mean differences between sexes were statistically significant in weight, height, TSF, SSF, PBF, PBFAZ, FM, FFM, FMI and FFMI (p<0.05), except in BMI (p>0.05). These results are important for future investigations in clinical and epidemiological settings so as to accurately identify the risk of lower or higher adiposity and body composition using PBF, FM and FFM.