The Sexual Dimorphism of Human Adipose Depots

Sexual dimorphism in the association of umbilical cord blood lipidome with abdominal fat in early childhood

BACKGROUND

Although the associations between cord blood lipidome and neonatal birth weight are established, it remains uncertain whether sexual dimorphism in fetal fat accumulation extends to the relationship between cord blood lipid profiles and neonatal abdominal fat compartments. Understanding these relationships could provide insights into early sex-specific differences in lipid metabolism.

METHODS

We conducted lipidomics of umbilical cord blood plasma samples (350 (46.6%) girls and 401 (53.4%) boys) from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort. Abdominal fat compartments-superficial subcutaneous adipose tissue (sSAT), deep SAT (dSAT), and intra-abdominal adipose tissue (IAT)-were quantified by magnetic resonance imaging within 2 weeks of birth in 239 subjects. Linear regression models were used to assess sex differences in lipid species associated with abdominal fat compartments.

RESULTS

Newborn girls had significantly higher superficial and deep subcutaneous adipose tissue volumes compared to boys, whereas intra-abdominal adipose tissue volumes were similar between sexes. In the pooled analysis, cord blood plasma lipids showed distinct associations with different fat depots: 38 lipid species were associated with sSAT, 4 with dSAT, and 38 with IAT. In sex-stratified analyses, 13 lipids were associated with sSAT in girls and 3 in boys, whereas dSAT showed associations with 45 lipids in boys but none in girls. These sex differences were primarily observed in ether-linked phospholipids and ceramides. Notably, no significant associations were observed between lipids and IAT in either sex, suggesting depot-specific sexual dimorphism in early life.

CONCLUSIONS

Our study reveals sexual dimorphism in the associations between cord blood lipidome and abdominal adiposity, suggesting depot-specific patterns in adipose tissue development and lipid metabolism in early life.

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.

Association of BMI with mortality and health-related quality of life among 4.4 million adults: Evidence from a nationwide, population-based, prospective cohort study

AIMS

The body mass index (BMI), as an easy-to-calculate measure of body fatness, is closely associated with all-cause mortality, but few studies with a large enough scale have examined the relationship between BMI and quality of life. A comprehensive and precise insight into a new range is needed.

MATERIALS AND METHODS

Based on the ChinaHEART (Health Evaluation And risk Reduction through nationwide Teamwork), a nationwide, population-based cohort study, 4,485,773 participants living in 20,159 communities or villages were passively followed for death records, through a linkage of data with the National Mortality Surveillance System and Vital Registration. Firstly, we conducted Cox proportional-hazards regression models to assess the hazard ratios (HRs) of BMI on the risk of all-cause and cause-specific mortality. Secondly, we used logistic regression models to examine associations between BMI and health-related quality of life (HRQL). Fully adjusted models were adjusted for age, sex, annual household income, occupation, education level, marriage, medical insurance, urbanity, tobacco smoking, alcohol consumption and the history of hypertension, diabetes mellitus, dyslipidaemia and cardiovascular disease (CVD).

RESULTS

Among the 4 485 773 included participants with an average age of 56.4 ± 10.0 years, 59.0% were female. During the follow-up period, which had a median duration of 5.3 years, a total of 142 004 cases of all-cause mortality were confirmed. After adjusting for participant characteristics and lifestyles, we observed the U-shaped association between BMI and all-cause mortality with an inflection of 26-27 kg/m2, and the estimated HR per 1 kg/m2 increase in BMI was 0.92 (95% CI 0.92-0.93) and 1.03 (95% CI 1.03-1.04) below and above the turning point, respectively. An inverted J-shape pattern between BMI and HRQL with a peak of 22-23 kg/m2 was found, in which the odd ratio per 1 kg/m2 increase in BMI was 0.98 (95% CI 0.98, 0.99) below 22-23 kg/m2 and 1.03 (95% CI 1.03-1.03) above this point.

CONCLUSIONS

We found distinct ranges of BMI for minimized mortality risk and maximized HRQL. The BMI range corresponding to the HRQL is lower than the BMI range corresponding to the lowest risk of death generally. Therefore, it is worth considering how to define the new recommended range for a new BMI based on the goal of 'living a longer and healthier life'.

Exploring Visceral Fat as a Screening Marker for Cardiometabolic Risk in Children and Adolescents

Objective: To establish and validate age- and sex-specific visceral fat area (VFA) cutoff values for the effective identification of cardiometabolic risk (CMR) in children and adolescents. Methods: A cross-sectional study involving 8133 participants was conducted to derive age- and sex-specific VFA cutoffs, which were validated in a longitudinal cohort comprising 10,805 individuals. The predictive performance of the derived VFA cutoffs for CMR was evaluated using the area under the receiver operating characteristic curve (AUC). Additionally, logistic regression models were utilized to calculate the relative risk (RR) of CMR associated with elevated VFA levels. Results: The 75th percentile of the VFA was identified as the optimal cutoff for screening for hypertension, hyperglycemia, dyslipidemia, and CMR clustering in boys. In girls, the 75th percentile was optimal for screening hypertension, dyslipidemia, and CMR clustering, while the 80th percentile proved best for hyperglycemia. No significant difference in predicative performance was observed between the optimal and simplified VFA cutoffs. Longitudinal validation demonstrated that individuals exceeding the VFA cutoff had a significantly higher risk for CMR, with RRs ranging from 1.33 to 3.89 (all p < 0.001) for boys and from 1.63 to 3.16 (all p < 0.001) for girls. Notably, normal-weight boys with VFA above the cutoff had a significantly higher CMR risk compared to their peers in other weight status categories. Conclusions: Both the optimal and simplified VFA cutoffs are robust tools for screening CMR in Chinese children and adolescents, with significant implications for early intervention strategies.

Intermittent fasting as a dietary intervention with potential sexually dimorphic health benefits

Intermittent fasting (IF) has proven to be a feasible dietary intervention for the wider population. The recent increase in IF clinical trials highlights its potential effects on health, including changes in body composition, cardiometabolic status, and aging. Although IF may have clinical applications in different populations, studies suggest there may be sex-specific responses in parameters such as body composition or glucose and lipid metabolism. Here, the existing literature on IF clinical trials is summarized, the application of IF in both disease prevention and management is discussed, and potential disparities in response to this type of diet between men and women are assessed. Moreover, the potential mechanisms that may be contributing to the sexually dimorphic response, such as age, body composition, tissue distribution, or sex hormones are investigated. This review underscores the need to further study these sex-specific responses to IF to define the most effective time frames and length of fasting periods for men and women. Tailoring IF to specific populations with a personalized approach may help achieve its full potential as a lifestyle intervention with clinical benefits.

Baseline and early changes in CT body composition can predict recurrence-free survival after radical gastrectomy: A sex-specific study

OBJECTIVE

This study aimed to explore the predictive value of baseline CT body composition and its early changes on recurrence-free survival (RFS) following radical gastrectomy, while also assessing potential sex-related differences.

METHODS

We conducted a retrospective analysis of gastric cancer (GC) patients with confirmed pathology from October 2019 to May 2023. All patients underwent preoperative and postoperative CT scans to assess visceral fat area (VFA), subcutaneous fat area (SFA), skeletal muscle area (SMA), and skeletal muscle density (SMD), along with calculating their respective rates of change. Multivariate Cox regression analyses were used to identify independent predictors of RFS in male and female patients separately, and nomogram models were subsequently developed. The models' predictive performance was assessed using calibration curves, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA).

RESULTS

The study included 287 patients, consisting of 185 males and 102 females. At baseline, males had a lower subcutaneous adipose tissue index (SATI) but higher skeletal muscle index (SMI) and SMD compared to females (p＜0.001). Postoperatively, both SATI and visceral adipose tissue index (VATI) were significantly lower in both males and females than their corresponding preoperative values (p＜0.005). In males, SMI (HR = 0.442, p = 0.002), VATI (HR = 1.843, p = 0.018), lymphocyte (LYM) (HR = 0.486, p = 0.040), pathological T stage (HR = 3.004, p = 0.003), and postoperative complication (POC) (HR = 1.893, p = 0.014) were found to be independent predictors of RFS. In females, independent predictors of RFS included SMI (HR = 0.361, p = 0.013), SATI change rate (δSATI) (HR = 0.428, p = 0.024), albumin (ALB) (HR = 0.242, p = 0.003), CEA (HR = 5.418, p < 0.001), and POC (HR = 3.425, p < 0.001). The male-specific nomogram model demonstrated predictive accuracy for recurrence-free survival (RFS), with areas under the ROC curve (AUC) of 0.621, 0.783, and 0.796 at 1, 2, and 3 years, respectively. Similarly, the female-specific nomogram model achieved AUCs of 0.796, 0.836, and 0.783 at the corresponding time points. Calibration curves indicated a strong concordance between predicted and observed outcomes, while DCA validated the clinical utility of both models. Additionally, the models effectively stratified patients into low-risk and high-risk groups.

CONCLUSION

Sex differences were observed in the predictive value of CT body composition for RFS after gastrectomy. By incorporating CT body composition parameters and clinical indicators, sex-specific nomogram models were developed, demonstrating effective prediction of RFS in gastric cancer patients post-surgery.

Linear and non-linear relationships between body fat mass distribution and bone mineral density in adults: The NHANES, 2011-2018

OBJECTIVE

The relationship between body fat mass and bone mineral density (BMD) remains controversial. This research aimed to explore the linear or non-linear relationship between body fat mass and BMD among adults in the United States.

METHODS

This cross-sectional study identified adults aged 18 years or older in the National Health and Nutrition Examination Survey from 2011 to 2018. After adjusting for covariates, linear relationships between body fat mass and BMD in different genders were tested by generalized linear models, and potential non-linear relationships were explored by generalized additive models and piecewise linear regression models.

RESULTS

The research included 4691 (57.9% of the total sample) males and 3417 (42.1% the of total sample) females. In both males and females, we found a negative association between android or total body fat mass and lumbar spine BMD and a positive association between appendicular, android, gynoid, or total body fat mass and whole body BMD (all P < 0.05). The relationships between body fat mass in all regions and lumbar spine BMD were U-shaped in males and inverted U-shaped in females (all Pnon-linear < 0.05). Inverted U-shaped relationships existed between body fat mass in all regions and whole body BMD in females (all Pnon-linear < 0.05).

CONCLUSIONS

Body fat mass was negatively and linearly associated with lumbar spine BMD, but positively associated with whole body BMD. Body fat mass had a U-shaped relationship with lumbar spine BMD in males and an inverted U-shaped association with lumbar spine and whole body BMD in females.

Improved whole-mount immunofluorescence protocol for consistent and robust labeling of adult Drosophila melanogaster adipose tissue

Energy storage and endocrine functions of the Drosophila fat body make it an excellent model for elucidating mechanisms that underlie physiological and pathophysiological organismal metabolism. Combined with Drosophila's robust genetic and immunofluorescence microscopy toolkits, studies of Drosophila fat body function are ripe for cell biological analysis. Unlike the larval fat body, which is easily removed as a single, cohesive sheet of tissue, isolating intact adult fat body proves to be more challenging, thus hindering consistent immunofluorescence labeling even within a single piece of adipose tissue. Here, we describe an improved approach to handling Drosophila abdomens that ensures full access of the adult fat body to solutions generally used in immunofluorescence labeling protocols. In addition, we assess the quality of fluorescence reporter expression and antibody immunoreactivity in response to variations in fixative type, fixation incubation time, and detergent used for cellular permeabilization. Overall, we provide several recommendations for steps in a whole-mount staining protocol that results in consistent and robust immunofluorescence labeling of the adult Drosophila fat body.

Obesity: a gender-view

PURPOSE

There is a growing awareness of the importance of understanding gender differences in obesity. The aim of this short review was to revise the current evidence on anthropometric characteristics and nutritional and pharmacological aspects of obesity from a gender perspective.

METHODS

A literature search within PubMed was performed. Selected publications related to obesity and gender differences were reviewed.

RESULTS

The prevalence of obesity among men is higher than in women, but women have a higher percentage of body fat content compared to men, and gender appears to be an important factor in the manifestation of central (android) or peripheral (gynoid) obesity. In addition, while in most clinical trials, women are still underrepresented, in clinical registration trials of anti-obesity drugs, women are commonly up-represented and gender-specific analysis is uncommon. Considering that adipose tissue is one of the factors affecting the volume of distribution of many drugs, mainly lipophilic drugs, gender differences might be expected in the pharmacokinetics and pharmacodynamics of anti-obesity drugs. Indeed, although Liraglutide 3 mg, a long-acting glucagon-like peptide-1 receptor agonist, and naltrexone/bupropion display lipophilic properties, currently, a gender-dose adjustment for both these drugs administration is not recommended. In addition, despite that predicted responders to treatment offer substantial opportunities for efficient use, especially of expensive new therapies, such as anti-obesity drugs, data on gender differences to identify early responders to both these have not yet been investigated. Finally, bariatric surgery gender disparity reflects healthcare practices. Weight loss similar, but differing effects: women need more correction and face psychology challenges; men have worse physiology and fewer comorbidity improvements.

CONCLUSION

Gender differences exist in obesity prevalence and phenotype, body fat distribution, drug efficacy, clinical trial representation, and different secondary effects of bariatric surgery. Gender is an important variable in obesity analysis.

The impact of chromosomal sex on cardiometabolic health and disease

Many aspects of metabolism are sex-biased, from gene expression in metabolic tissues to the prevalence and presentation of cardiometabolic diseases. The influence of hormones produced by male and female gonads has been widely documented, but recent studies have begun to elucidate the impact of genetic sex (XX or XY chromosomes) on cellular and organismal metabolism. XX and XY cells have differential gene dosage conferred by specific genes that escape X chromosome inactivation or the presence of Y chromosome genes that are absent from XX cells. Studies in mouse models that dissociate chromosomal and gonadal sex have uncovered mechanisms for sex-biased epigenetic, transcriptional, and post-transcriptional regulation of gene expression in conditions such as obesity, atherosclerosis, pulmonary hypertension, autoimmune disease, and Alzheimer's disease.

Processing Adipose Tissue Samples in a GMP Environment Standardizes the Use of SVF in Cell Therapy Treatments: Data on 302 Patients

Stromal vascular fraction (SVF) cells, together with adipose-derived mesenchymal stem cells, are becoming the tool of choice for many clinical applications. Currently, nearly 200 clinical trials are running worldwide to prove the efficacy of this cell type in treating many diseases and pathological conditions. To reach the goals of cell therapies and produce ATMPs as drugs for regenerative medicine, it is necessary to properly standardize GMP processes and, thus, collection methods, transportation strategies, extraction protocols, and characterization procedures, without forgetting that all the tissues of the human body are characterized by a wide inter-individual variability which is genetically determined and acquired during life. Here, we compare 302 samples processed under GMP rules to exclude the influence of the operator and of the anatomical site of collection. The influence of variability in the ages and genders of patients, along with laboratory parameters such as total cell number, cell viability, stem cell number, and other stromal vascular fraction cell subpopulations, has been compared. The results show that when the laboratory protocol is standardized, the variability of quantifiable cell parameters is widely statistically non-significant, meaning that we can take a further step toward standardized advanced cell therapy products.

Quantification of the renal sinus fat and exploration of its relationship with ectopic fat deposition in normal subjects using MRI fat fraction mapping

Purpose

To determine the renal sinus fat (RSF) volume and fat fraction (FF) in normal Chinese subjects using MRI fat fraction mapping and to explore their associations with age, gender, body mass index (BMI) and ectopic fat deposition.

Methods

A total of 126 subjects were included in the analysis. RSF volume and FF, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) area, and hepatic and pancreatic FFs were measured for each subject. The comparisons in gender were determined using two-tailed t-tests or the nonparametric Mann-Whitney U-test for normally or non-normally distributed data for continuous variables and the chi-square test for categorical variables. Comparisons of RFS volume and FF between right and left kidneys were determined using paired sample t-tests. Multivariable logistic models were performed to confirm whether RSF differences between men and women are independent of VAT or SAT area. When parameters were normally distributed, the Pearson correlation coefficient was used; otherwise, the Spearman correlation coefficient was applied.

Results

The RSF volumes (cm3) of both kidneys in men (26.86 ± 8.81 for right and 31.62 ± 10.32 for left kidneys) were significantly bigger than those of women (21.47 ± 6.90 for right and 26.03 ± 8.55 for left kidneys) (P < 0.05). The RSF FFs (%) of both kidneys in men (28.33 ± 6.73 for right and 31.21 ± 6.29 for left kidneys) were significantly higher than those of the women (23.82 ± 7.74 for right and 27.92 ± 8.15 for left kidneys) (P < 0.05). The RSF differences between men and women are independent of SAT area and dependent of VAT area (except for right RSF volume). In addition, the RSF volumes and FFs in both kidneys in the overall subjects show significant correlations with age, BMI, VAT area, hepatic fat fraction and pancreatic fat fraction (P < 0.05). However, the patterns of these correlations varied by gender. The RSF volume and FF of left kidney were significantly larger than those of the right kidney (P < 0.05).

Conclusion

The association between renal sinus fat and ectopic fat deposition explored in this study may help establish a consensus on the normal values of RSF volume and FF for the Chinese population. This will facilitate the identification of clinicopathological changes and aid in the investigation of whether RSF volume and FF can serve as early biomarkers for metabolic diseases and renal dysfunction in future studies.

Programming Mechanism of Adipose Tissue Expansion in the Rat Offspring of Obese Mothers Occurs in a Sex-Specific Manner

We investigated whether excessive retroperitoneal adipose tissue (AT) expansion programmed by maternal obesity (MO) affects adipocyte size distribution and gene expression in relation to adipocyte proliferation and differentiation in male and female offspring (F1) from control (F1C) and obese (F1MO) mothers. Female Wistar rats (F0) ate a control or high-fat diet from weaning through pregnancy and lactation. F1 were weaned onto a control diet and euthanized at 110 postnatal days. Fat depots were weighed to estimate the total AT. Serum glucose, triglyceride, leptin, insulin, and the insulin resistance index (HOMA-IR) were determined. Adipocyte size and adipogenic gene expression were examined in retroperitoneal fat. Body weight, retroperitoneal AT and adipogenesis differed between male and female F1Cs. Retroperitoneal AT, glucose, triglyceride, insulin, HOMA-IR and leptin were higher in male and female F1MO vs. F1C. Small adipocytes were reduced in F1MO females and absent in F1MO males; large adipocytes were increased in F1MO males and females vs. F1C. Wnt, PI3K-Akt, and insulin signaling pathways in F1MO males and Egr2 in F1MO females were downregulated vs. F1C. MO induced metabolic dysfunction in F1 through different sex dimorphism mechanisms, including the decreased expression of pro-adipogenic genes and reduced insulin signaling in males and lipid mobilization-related genes in females.

Sex differences in thermoregulation in mammals: Implications for energy homeostasis

Thermal homeostasis is a fundamental process in mammals, which allows the maintenance of a constant internal body temperature to ensure an efficient function of cells despite changes in ambient temperature. Increasing evidence has revealed the great impact of thermoregulation on energy homeostasis. Homeothermy requires a fine regulation of food intake, heat production, conservation and dissipation and energy expenditure. A great interest on this field of research has re-emerged following the discovery of thermogenic brown adipose tissue and browning of white fat in adult humans, with a potential clinical relevance on obesity and metabolic comorbidities. However, most of our knowledge comes from male animal models or men, which introduces unwanted biases on the findings. In this review, we discuss how differences in sex-dependent characteristics (anthropometry, body composition, hormonal regulation, and other sexual factors) influence numerous aspects of thermal regulation, which impact on energy homeostasis. Individuals of both sexes should be used in the experimental paradigms, considering the ovarian cycles and sexual hormonal regulation as influential factors in these studies. Only by collecting data in both sexes on molecular, functional, and clinical aspects, we will be able to establish in a rigorous way the real impact of thermoregulation on energy homeostasis, opening new avenues in the understanding and treatment of obesity and metabolic associated diseases.