Shaping fat distribution: New insights into the molecular determinants of depot- and sex-dependent adipose biology

Association between Variants of the TRPV1 Gene and Body Composition in Sub-Saharan Africans

In humans, the transient receptor potential vanilloid 1 (TRPV1) gene is activated by exogenous (e.g., high temperatures, irritating compounds such as capsaicin) and endogenous (e.g., endocannabinoids, inflammatory factors, fatty acid metabolites, low pH) stimuli. It has been shown to be involved in several processes including nociception, thermosensation, and energy homeostasis. In this study, we investigated the association between TRPV1 gene variants, sensory perception (to capsaicin and PROP), and body composition (BMI and bioimpedance variables) in human populations. By comparing sequences deposited in worldwide databases, we identified two haplotype blocks (herein referred to as H1 and H2) that show strong stabilizing selection signals (MAF approaching 0.50, Tajima's D > +4.5) only in individuals with sub-Saharan African ancestry. We therefore studied the genetic variants of these two regions in 46 volunteers of sub-Saharan descent and 45 Italian volunteers (both sexes). Linear regression analyses showed significant associations between TRPV1 diplotypes and body composition, but not with capsaicin perception. Specifically, in African women carrying the H1-b and H2-b haplotypes, a higher percentage of fat mass and lower extracellular fluid retention was observed, whereas no significant association was found in men. Our results suggest the possible action of sex-driven balancing selection at the non-coding sequences of the TRPV1 gene, with adaptive effects on water balance and lipid deposition.

Visceral fat area is more strongly associated with arterial stiffness than abdominal subcutaneous fat area in Chinese patients with type 2 diabetes

BACKGROUND

Few studies have compared the correlation between visceral fat area (VFA) and abdominal subcutaneous fat area (SFA) with arterial stiffness (AS) in patients with type 2 diabetes (T2D). In addition, there is currently controversy regarding the correlation between VFA and SFA with AS. We aimed to investigate the relationship between VFA and SFA with AS in patients with T2D.

METHODS

In this cross-sectional study, 1475 Chinese T2D patients with an average age of 52.32 ± 10.96 years were included. VFA and SFA were determined by a dual bioelectrical impedance analyzer, and AS was determined by measurement of brachial-ankle pulse wave conduction velocity (baPWV). Atherosclerosis was deemed present in study participants with baPWV values higher than 75th percentile (1781 cm/s). Independent correlations of logVFA and logSFA with AS were assessed using multiple linear regression and multivariate logistic regression.

RESULTS

The baPWV was linked with VFA, waist circumference, and women's SFA in a general linear correlation study (P < 0.05), but not with body mass index (P = 0.3783) or men's SFA (P = 0.1899). In both men and women, VFA and SFA were positively correlated with AS, according to the generalized additive model (GAM). After fully adjusting for confounders, multiple linear regression analyses showed that for every 1-unit increase in logVFA, the beta coefficient of baPWV increased by 63.1 cm/s (95% CI: 18.4, 107.8) (P < 0.05). logSFA did not correlate significantly with baPWV (P = 0.125). In the multiple logistic regression analysis, the odds ratio (OR) of elevated baPWV was 1.8 (95% CI: 1.1, 3.1) (P = 0.019) per 1-unit increase in logVFA. logSFA did not correlate significantly with AS (P = 0.091). In the subgroup analysis, the correlation between logVFA and baPWV did not interact across subgroups (P-interaction > 0.05).

CONCLUSIONS

Compared with SFA, VFA had a stronger independent positive correlation with AS in Chinese T2D patients. Patients with T2D should pay more attention to monitoring VFA and lowering it to minimize cardiovascular events.

Increased visceral fat area to skeletal muscle mass ratio is positively associated with the risk of metabolic dysfunction-associated steatotic liver disease in a Chinese population

BACKGROUND

The diagnosis and comprehension of nonalcoholic fatty liver disease (NAFLD), recently redefined as metabolic dysfunction-associated steatotic liver disease (MASLD) are gaining a better understanding. In this study, we examined the association between visceral fat area and skeletal muscle mass ratio (VSR) and the prevalence of MASLD in a Chinese population.

METHODS

A cross-sectional study was conducted involving 10,916 individuals who underwent bioelectrical impedance analysis, along with anthropometric and biochemical measurements, from January 2022 to June 2023. According to the VSR distribution, sex-specific quartiles of VSR within the study population were defined. Linear trend tests were performed for the categorized VSR variables. Logistic regression models were performed to estimate the odds ratio and 95% confidence intervals between VSR distribution and MASLD prevalence stratified by sex.

RESULTS

The prevalence of MASLD was 37.94% in the overall population (56.34% male), and it gradually increased with higher VSR levels in both genders (P < 0.001). Logistic regression analysis demonstrated a significant association between VSR and MASLD prevalence after adjusting for confounders. The odds ratio (95% confidence interval) for MASLD, comparing the lowest to the highest VSR quartile, was 3.159 (2.671, 3.736) for men and 2.230 (1.764, 2.819) for women (all P < 0.001). Restricted cubic splines also indicated significant non-linear relationships between VSR and MASLD prevalence.

CONCLUSIONS

VSR is positively associated with the prevalence of MASLD in this Chinese population, with a notably higher risk for men as VSR increases compared to women.

Resident tissue macrophages: Key coordinators of tissue homeostasis beyond immunity

Resident tissue macrophages (RTMs) encompass a highly diverse set of cells abundantly present in every tissue and organ. RTMs are recognized as central players in innate immune responses, and more recently their importance beyond host defense has started to be highlighted. Despite sharing a universal name and several canonical markers, RTMs perform remarkably specialized activities tailored to sustain critical homeostatic functions of the organs they reside in. These cells can mediate neuronal communication, participate in metabolic pathways, and secrete growth factors. In this Review, we summarize how the division of labor among different RTM subsets helps support tissue homeostasis. We discuss how the local microenvironment influences the development of RTMs, the molecular processes they support, and how dysregulation of RTMs can lead to disease. Last, we highlight both the similarities and tissue-specific distinctions of key RTM subsets, aiming to coalesce recent classifications and perspectives into a unified view.

Association between the ZJU index and risk of new-onset non-alcoholic fatty liver disease in non-obese participants: a Chinese longitudinal prospective cohort study

Background

Non-alcoholic fatty liver disease (NAFLD) is increasingly observed in non-obese individuals. The ZJU (Zhejiang University) index has been established as a new and efficient tool for detecting NAFLD, but the relationship between the ZJU index and NAFLD within non-obese individuals still remains unclear.

Methods

A post-hoc evaluation was undertaken using data from a health assessment database by the Wenzhou Medical Center. The participants were divided into four groups based on the quartile of the ZJU Index. Cox proportional hazards regression, Kaplan-Meier analysis and tests for linear trends were used to evaluate the relationship between the ZJU index and NAFLD incidence. Subgroup analysis was conducted to test the consistency of the correlation between ZJU and NAFLD in subsgroups. Receiver operative characteristic (ROC) curve analysis was performed to evaluate the predictive performance of the ZJU index, compared with the Atherogenic index of plasma (AIP) and Remnant lipoprotein cholesterol (RLP-C) index.

Results

A total of 12,127 were included in this study, and 2,147 participants (17.7%) developed NAFLD in 5 years follow-up. Participants in higher ZJU quartiles tended to be female and have higher liver enzymes (including ALP, GGT, ALT, AST), GLU, TC, TG, LDL and higher NAFLD risk. Hazard Ratios (HR) and 95% confidence intervals (CI) for new-onset NAFLD in Q2, Q3, and Q4 were 3.67(2.43 to 5.55), 9.82(6.67 to 14.45), and 21.67(14.82 to 31.69) respectively in the fully adjusted model 3. With increased ZJU index, the cumulative new-onset NAFLD gradually increased. Significant linear associations were observed between the ZJU index and new-onset NAFLD (p for trend all<0.001). In the subgroup analysis, we noted a significant interaction in sex, with HRs of 3.27 (2.81, 3.80) in female and 2.41 (2.21, 2.63) in male (P for interaction<0.01). The ZJU index outperformed other indices with an area under the curve (AUC) of 0.823, followed by AIP (AUC=0.747) and RLP-C (AUC=0.668).

Conclusion

The ZJU index emerges as a promising tool for predicting NAFLD risk in non-obese individuals, outperforming other existing parameters including AIP and RLP-C. This could potentially aid in early detection and intervention in this specific demographic.

Influence of nonalcoholic fatty liver disease on inflammatory bowel disease hospitalizations in the United States

Background

The reported prevalence of nonalcoholic fatty liver disease (NAFLD) in patients with inflammatory bowel disease (IBD) is 32%. We assessed the influence of NAFLD on IBD hospitalizations in the United States (US).

Methods

We utilized the National Inpatient Sample database, from 2016-2019, to identify the total IBD hospitalizations in the US and we further subdivided them according to the presence or absence of NAFLD. Hospitalization characteristics, comorbidities and outcomes were compared. Statistical significance was set at P<0.05.

Results

There were 1,272,260 IBD hospitalizations in the US, of which 5.04% involved NAFLD. For IBD hospitalizations with NAFLD, the mean age was 50-64 years, and the proportion of males was 46.97%. IBD hospitalizations with NAFLD had a lower proportion of African Americans (8.7% vs. 11.38%, P<0.001). Comorbidities such as hypertension (50.34% vs. 44.04%, P<0.001) and obesity (18.77% vs. 11.81%, P<0.001) were significantly higher in the NAFLD cohort. Overall, based on the Charlson Comorbidity Index, patients with NAFLD had a higher number of comorbidities (52.77% vs. 20.66%, P<0.001). Mortality was higher in the NAFLD compared to the non-NAFLD cohort (3.14% vs. 1.44%, P<0.001). Patients with NAFLD also incurred significantly higher hospital charges ($69,536 vs. $55,467, p<0.001) and had a longer mean length of stay (6.10 vs. 5.27 days, P<0.001) compared to the cohort without NAFLD. Complications and inpatient procedure requirements were also higher in the NAFLD cohort.

Conclusion

Our study revealed greater mortality, morbidity, and healthcare resource utilization in patients with IBD who were hospitalized with a concomitant diagnosis of NAFLD.

Gender-affirming hormone therapy decreases d-dimer but worsens insulin sensitivity in transgender women

OBJECTIVES

Gender-affirming hormonal therapies (GAHT) and HIV increase cardiovascular risk for transgender women (TW), yet there is a paucity of data quantifying cardiometabolic changes following GAHT initiation, particularly among TW with HIV.

METHODS

The Féminas study enrolled TW from October 2016 to March 2017 in Lima, Peru. Participants reported sexual activity that was high risk for HIV acquisition or transmission. All were tested for HIV/ sexually transmitted infection and were given access to GAHT (oestradiol valerate and spironolactone), HIV pre-exposure prophylaxis (PrEP) or antiretroviral therapy (ART) for 12 months. Biomarker measurement was done on stored serum, whereas fasting glucose and lipids were measured in real time.

RESULTS

In all, 170 TW (32 with HIV, 138 without HIV) had median age 27 years and 70% prior GAHT use. At baseline, PCSK9, sCD14, sCD163, IL-6, sTNFRI/II, CRP and EN-RAGE levels were significantly higher in TW with HIV than in TW without HIV. High-density lipoprotein and total cholesterol were lower and insulin and glucose parameters were similar. All TW with HIV started ART, but only five achieved virological suppression at any time. No TW without HIV initiated PrEP. Over 6 months, all participants initiated GAHT and had worsening insulin, glucose and HOMA-IR. Large d-dimer decreases also occurred. Similar changes occurred in TW with and without HIV.

CONCLUSIONS

In this unique cohort of TW, GAHT decreased d-dimer but worsened insulin sensitivity. Because PrEP uptake and ART adherence were very low, observed effects are primarily attributed to GAHT use. Further study is needed to better understand cardiometabolic changes in TW by HIV serostatus.

Sex differences in FASN protein concentrations in urinary exosomes related to serum triglycerides levels in healthy adults

BACKGROUND

Dysregulation of lipid metabolism is the most prominent metabolic alteration observed in obesity, cancer, and cardiovascular diseases. The present study aimed to explore the sex differences associated with lipid metabolism in urinary exosome proteins, and evaluate the correlation of urinary exosome proteins with serum lipid biomarkers.

METHODS

The key enzymes regulating lipid metabolism in healthy adults were screened using urinary exosome data. Urinary exosomes were isolated from 120 healthy subjects and the expression of urinary proteins was assessed by Western blotting and ELISA. The correlation between urinary protein concentrations and the levels of serum lipid biomarkers was analyzed using correlation analysis.

RESULTS

Three urinary exosome proteins, namely fatty acid synthase (FASN), phosphoenolpyruvate carboxykinase (PCK1), and ATP-citrate synthase (ACLY) were identified, and only FASN showed sex differences. Sex differences were also observed in the serum triglyceride (TG) levels. Healthy males had higher FASN levels than females, and a moderate positive correlation was found between FASN concentrations and serum TG levels in healthy males (r = 0.479, P < 0.05). FASN concentrations in different age groups were positively correlated with the level of serum TG (18 ~ 30 years, r = 0.502; 31 ~ 44 years, r = 0.587; 45 ~ 59 years, r = 0.654; all P < 0.05). In addition, FASN concentrations was positively related to the increase in serum TG levels (range:1.0 ~ 1.7 mmol/L; r = 0.574, P < 0.05).

CONCLUSIONS

Sex differences were observed in urinary exosome FASN protein levels in healthy adults. FASN protein levels positively correlated with increased serum TG levels. FASN may serve as a novel biomarker to evaluate fatty acid synthesis in the human body.

Gluteal Augmentation in Men

The shape and definition of the male buttock have been emphasized throughout time, as it represents masculinity, strength, health, and beauty across various cultures. Aesthetic Plastic Surgery in general has become more acceptable for men; thus, the demand for gluteal enhancement parallels this shift in social norms. Surgeons interested in such cases must first understand the aesthetic ideals and principles of gluteal shaping as it pertains to men. By using gluteal implants, fat transfer techniques, local tissue rearrangement principles, or a combination thereof, one can sculpt an aesthetically pleasing male buttock with a high degree of patient satisfaction.

Role of gender in explaining metabolic syndrome risk factors in an Iranian rural population using structural equation modelling

Many factors can lead to an increase in the prevalence of metabolic syndrome (MetS) in different populations. Using an advanced structural equation model (SEM), this study is aimed to determine the most important risk factors of MetS, as a continuous latent variable, using a large number of males and females. We also aimed to evaluate the interrelations among the associated factors involved in the development of MetS. This study used data derived from the Fasa PERSIAN cohort study, a branch of the PERSIAN cohort study, for participants aged 35 to 70 years with 10,138 males and females. SEM was used to evaluate the direct and indirect effects, as well as gender effects of influencing factors. Results from the SEM showed that in females most changes in MetS are described by waist circumference (WC), followed by hypertension (HP) and triglyceride (TG), while in males most changes in MetS are described by WC, followed by TG then fasting blood glucose (FBG). Results from the SEM confirmed the gender effects of social status on MetS, mediated by sleep and controlled by age, BMI, ethnicity and physical activity. This study also shows that the integration of TG and WC within genders could be useful as a screening criterion for MetS in our study population.

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.

Obese Adipocytes Have Altered Redox Homeostasis with Metabolic Consequences

White and brown adipose tissues are organized to form a real organ, the adipose organ, in mice and humans. White adipocytes of obese animals and humans are hypertrophic. This condition is accompanied by a series of organelle alterations and stress of the endoplasmic reticulum. This stress is mainly due to reactive oxygen species activity and accumulation, lending to NLRP3 inflammasome activation. This last causes death of adipocytes by pyroptosis and the formation of large cellular debris that must be removed by macrophages. During their chronic scavenging activity, macrophages produce several secretory products that have collateral consequences, including interference with insulin receptor activity, causing insulin resistance. The latter is accompanied by an increased noradrenergic inhibitory innervation of Langerhans islets with de-differentiation of beta cells and type 2 diabetes. The whitening of brown adipocytes could explain the different critical death size of visceral adipocytes and offer an explanation for the worse clinical consequence of visceral fat accumulation. White to brown transdifferentiation has been proven in mice and humans. Considering the energy-dispersing activity of brown adipose tissue, transdifferentiation opens new therapeutic perspectives for obesity and related disorders.

Deficiency of Adipose Aryl Hydrocarbon Receptor Protects against Diet-Induced Metabolic Dysfunction through Sexually Dimorphic Mechanisms

The molecular mechanisms underlying diet-induced obesity are complex and remain unclear. The activation of the aryl hydrocarbon receptor (AhR), a xenobiotic sensor, by obesogens may contribute to diet-induced obesity through influences on lipid metabolism and insulin resistance acting at various sites, including adipose tissue. Thus, our hypothesis was that conditional AhR depletion, specifically from mature adipose tissue (CadKO), would improve high-fat diet (HFD)-induced metabolic dysfunction. CadKO protects mice from HFD-induced weight gain. CadKO females eat fewer calories, leading to increased energy expenditure (EE) and improved glucose tolerance on HFD. Our exploration of adipose tissue biology suggests that the depletion of AhR from adipocytes provides female mice with an increased capacity for adipogenesis and lipolysis, allowing for the maintenance of a healthy adipocyte phenotype. The HFD-induced leptin rise was reduced in CadKO females, but the hypothalamic leptin receptor (LepR) was increased in the energy regulatory regions of the hypothalamus, suggesting an increased sensitivity to leptin. The estrogen receptor α (ERα) was higher in CadKO female adipose tissue and the hypothalamus. CadKO males displayed a delayed progression of obesity and insulin resistance. In males, CadKO ameliorated proinflammatory adipocytokine secretion (such as TNFα, IL1β, IL6) and displayed reduced inflammatory macrophage infiltration into adipose depots. Overall, CadKO improves weight control and systemic glucose homeostasis under HFD challenge but to a more profound extent in females. CadKO facilitates a lean phenotype in females and mediates healthy adipose-hypothalamic crosstalk. In males, adipose-specific AhR depletion delays the development of obesity and insulin resistance through the maintenance of healthy crosstalk between adipocytes and immune cells.

Sex-specific responses in glucose-insulin homeostasis and lipoprotein-lipid components after high-dose supplementation with marine n-3 PUFAs in abdominal obesity: a randomized double-blind crossover study

Background

Clinical studies on effects of marine-derived omega-3 (n-3) polyunsaturated fatty acids (PUFAs), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and the plant-derived omega-6 (n-6) PUFA linoleic acid (LA) on lipoprotein-lipid components and glucose-insulin homeostasis have shown conflicting results, which may partly be explained by differential responses in females and males. However, we have lacked data on sexual dimorphism in the response of cardiometabolic risk markers following increased consumption of n-3 or n-6 PUFAs.

Objective

To explore sex-specific responses after n-3 (EPA + DHA) or n-6 (LA) PUFA supplementation on circulating lipoprotein subfractions, standard lipids, apolipoproteins, fatty acids in red blood cell membranes, and markers of glycemic control/insulin sensitivity among people with abdominal obesity.

Methods

This was a randomized double-blind crossover study with two 7-week intervention periods separated by a 9-week washout phase. Females (n = 16) were supplemented with 3 g/d of EPA + DHA (fish oil) or 15 g/d of LA (safflower oil), while males (n = 23) received a dose of 4 g/d of EPA + DHA or 20 g/d of LA. In fasting blood samples, we measured lipoprotein particle subclasses, standard lipids, apolipoproteins, fatty acid profiles, and markers of glycemic control/insulin sensitivity.

Results

The between-sex difference in relative change scores was significant after n-3 for total high-density lipoproteins (females/males: -11%*/-3.3%, p = 0.036; *: significant within-sex change), high-density lipoprotein particle size (+2.1%*/-0.1%, p = 0.045), and arachidonic acid (-8.3%*/-12%*, p = 0.012), and after n-6 for total (+37%*/+2.1%, p = 0.041) and small very-low-density lipoproteins (+97%*/+14%, p = 0.021), and lipoprotein (a) (-16%*/+0.1%, p = 0.028). Circulating markers of glucose-insulin homeostasis differed significantly after n-3 for glucose (females/males: -2.1%/+3.9%*, p = 0.029), insulin (-31%*/+16%, p < 0.001), insulin C-peptide (-12%*/+13%*, p = 0.001), homeostasis model assessment of insulin resistance index 2 (-12%*/+14%*, p = 0.001) and insulin sensitivity index 2 (+14%*/-12%*, p = 0.001), and quantitative insulin sensitivity check index (+4.9%*/-3.4%*, p < 0.001).

Conclusion

We found sex-specific responses after high-dose n-3 (but not n-6) supplementation in circulating markers of glycemic control/insulin sensitivity, which improved in females but worsened in males. This may partly be related to the sex differences we observed in several components of the lipoprotein-lipid profile following the n-3 intervention.

Clinical trial registration

https://clinicaltrials.gov/, identifier [NCT02647333].

Body composition and risk of liver cancer: a population-based prospective cohort study on gender difference

Background

Obesity is a common and highly convincing risk factor for many cancers, including liver cancer. Sex disparities in the body composition and regulatory mechanisms involved in energy homeostasis may contribute to the difference in the incidence of cancer. However, evidence on the gender-specific association between body composition and liver cancer incidence is limited. We performed this study to investigate the linear and non-linear associations of body composition with liver cancer risk by gender.

Materials and methods

This prospective analysis included 4,75,659 participants free of cancer, based on the UK Biobank. We used Cox proportional hazard models to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) after adjusting for potential confounders. Restricted cubic spline was performed to investigate the potential non-linear associations.

Results

During a median follow-up, 275 cases (174 male patients and 101 female patients) of liver cancer were identified. Male patients in the highest body fat percentage group are more likely to develop liver cancer (HR = 1.89, 95% CI: 1.17-3.03) compared with those in the lowest group. The one-unit increase of whole-body fat mass, arm fat mass, and trunk fat mass was associated with 1.03-, 1.14-, and 1.05-fold increased risk of liver cancer in male subjects, respectively. U-shaped associations of body composition with liver cancer risk were observed in the female subjects. Both high and low levels of whole-body fat-free mass, particularly in the arm and trunk, were associated with an increased risk of liver cancer.

Conclusion

This study found a gender-specific association between body composition and liver cancer risk and provided evidence for individualized weight management for the prevention of liver cancer.

Sex differences in glycolipidic disorders after exposure to maternal hyperglycemia during early development

PURPOSE

The aim of this review was to summarize sex differences in glycolipid metabolic phenotypes of human and animal models after exposure to maternal hyperglycemia and overview the underlying mechanisms, providing a new perspective on the maternal hyperglycemia-triggered risk of glycolipidic disorders in offspring.

METHODS

A comprehensive literature search within PubMed was performed. Selected publications related to studies on offspring exposed to maternal hyperglycemia investigating the sex differences of glycolipid metabolism were reviewed.

RESULTS

Maternal hyperglycemia increases the risk of glycolipid metabolic disorders in offspring, such as obesity, glucose intolerance and diabetes. Whether with or without intervention, metabolic phenotypes have been shown to exhibit sex differences between male and female offspring in response to maternal hyperglycemia, which may be related to gonadal hormones, organic intrinsic differences, placenta, and epigenetic modifications.

CONCLUSION

Sex may play a role in the different incidences and pathogenesis of abnormal glycolipid metabolism. More studies investigating both sexes are needed to understand how and why environmental conditions in early life affect long-term health between male and female individuals.

The Correlation of Apolipoprotein B with Alterations in Specific Fat Depots Content in Adults

Body mass index (BMI) and blood biomarkers are not enough to predict cardiovascular disease risk. Apolipoprotein B was identified to be associated with cardiovascular disease (CVD) progression. The Dual-energy X-ray Absorption (DXA) results could be considered as a predictor for cardiovascular disease in a more refined way based on fat distribution. The prediction of CVD risk by simple indicators still cannot meet clinical needs. The association of ApoB with specific fat depot features remains to be explored to better co-predict cardiovascular disease risk. An amount of 5997 adults from National Health and Nutrition Examination Survey (NHANES) were enrolled. Their demographic information, baseline clinical condition, blood examination, and DXA physical examination data were collected. Multivariate regression was used to assess the correlation between ApoB and site-specific fat characteristics through different adjusted models. Smooth curve fittings and threshold analysis were used to discover the turning points with 95% confidence intervals. ApoB is positively correlated with arms percent fat, legs percent fat, trunk percent fat, android percent fat, gynoid percent fat, arm circumference and waist circumference after adjustment with covariates for age, gender, race, hypertension, diabetes, hyperlipidemia, coronary heart disease, smoking status and vigorous work activity. The smooth curve fitting and threshold analysis also showed that depot-specific fat had lower turning points of ApoB in both males and females within the normal reference range of ApoB. Meanwhile, females have a lower increase in ApoB per 1% total percent fat and android percent fat than males before the turning points, while females have a higher growth of ApoB per 1% gynoid percent fat than males. The combined specific fat-depot DXA and ApoB analysis could indicate the risk of CVD in advance of lipid biomarkers or DXA alone.

Risk Factors of Non-alcoholic Fatty Liver Disease in the Iranian Adult Population: A Systematic Review and Meta-analysis

Context: Non-alcoholic fatty liver disease (NAFLD) is progressing considerably worldwide. Identifying the risk factors of NAFLD is a critical step in preventing its progression. Methods: In November 2022, two independent researchers studied seven databases, including PubMed, ISI/WoS, ProQuest, Scopus, SID, Magiran, and Google Scholar, and reference list of relevant articles, searching studies that assessed NAFLD risk factors in the Iranian adult population. Heterogeneity between studies was assessed by Cochran’s test and its composition using I2 statistics. A random-effects model was used when heterogeneity was observed; otherwise, a fixed-effects model was applied. Egger’s regression test and Trim-and-Fill analysis were used to assess publication bias. Comprehensive Meta-analysis software (version 3) was used for the analyses of the present study. Results: The results of this study showed significant associations between NAFLD with age [n = 15, odds ratio (OR) = 2.12, 95% CI: 1.79 - 2.51], body mass index (n = 46, OR = 5.00, 95% CI: 3.34 - 7.49), waist circumference (n = 20, OR = 6.37, 95% CI: 3.25 - 12.48), waist-to-hip ratio (n = 17, OR = 4.72, 95% CI: 3.93 - 5.66), total cholesterol (n = 39, OR = 1.80, 95% CI: 1.52 - 2.13), high-density lipoprotein (n = 37, OR = 0.53, 95% CI: 0.44 - 0.65), low-density lipoprotein (n = 31, OR = 1.68, 95% CI: 1.38 - 2.05), triglyceride (n = 31, OR = 3.21, 95% CI: 2.67 - 3.87), alanine aminotransferase (n = 26, OR = 4.06, 95% CI: 2.94 - 5.62), aspartate aminotransferase (n = 27, OR = 2.16, 95% CI: 1.50 - 3.12), hypertension (n = 13, OR = 2.53, 95% CI: 2.32 - 2.77), systolic blood pressure (n = 13, OR = 1.83, 95% CI: 1.53 - 2.18), diastolic blood pressure (n = 14, OR = 1.80, 95% CI: 1.48 - 2.20), fasting blood sugar (n = 31,OR = 2.91, 95% CI: 2.11- 4.01), homeostatic model assessment for insulin resistance (n = 5, OR = 1.92, 95% CI: 1.48 - 2.59), diabetes mellitus (n = 15, OR = 3.04, 95% CI: 2.46 - 3.75), metabolic syndrome (n = 10, OR = 3.56, 95% CI: 2.79 - 4.55), and physical activity (n = 11, OR = 0.32, 95% CI: 0.24 - 0.43) (P < 0.05). Conclusions: In conclusion, several factors are significantly associated with NAFLD. However, anthropometric indices had the strongest relationship with NAFLD in the Iranian adult population.

The role of oestrogen in determining sexual dimorphism in energy balance

Energy balance is determined by caloric intake and the rate at which energy is expended, with the latter comprising resting energy expenditure, physical activity and adaptive thermogenesis. The regulation of both energy intake and expenditure exhibits clear sexual dimorphism, with young women being relatively protected against weight gain and the development of cardiometabolic diseases. Preclinical studies have indicated that females are more sensitive to the satiety effects of leptin and insulin compared to males. Furthermore, females have greater thermogenic activity than males, whereas resting energy expenditure is generally higher in males than females. In addition to this, in post-menopausal women, the decline in sex steroid concentration, particularly in oestrogen, is associated with a shift in the distribution of adipose tissue and overall increased propensity to gain weight. Oestrogens are known to regulate energy balance and weight homeostasis via effects on both food intake and energy expenditure. Indeed, 17β-oestradiol treatment increases melanocortin signalling in the hypothalamus to cause satiety. Furthermore, oestrogenic action at the ventromedial hypothalamus has been linked with increased energy expenditure in female mice. We propose that oestrogen action on energy balance is multi-faceted and is fundamental to determining sexual dimorphism in weight control. Furthermore, evidence suggests that the decline in oestrogen levels leads to increased risk of weight gain and development of cardiometabolic disease in women across the menopausal transition.

Increased visceral fat area to skeletal muscle mass ratio is positively associated with the risk of cardiometabolic diseases in a Chinese natural population: A cross-sectional study

AIMS

Visceral adiposity and skeletal muscle loss may be positively correlated with cardiometabolic outcomes. This study aimed to explore the associations between the visceral fat area to skeletal muscle mass ratio (VSR) and the risk of cardiometabolic diseases in a Chinese natural population.

MATERIALS AND METHODS

A total of 5158 participants were included in this study. Body composition, anthropometrical, and biochemical measurements were performed. Body composition was assessed via the direct segmental multi-frequency bioelectrical impedance analysis method. The associations between VSR and metabolic associated fatty liver disease (MAFLD), hyperglycemia, hypertension, dyslipidemia, and hyperuricemia were analysed.

RESULTS

With the increase of VSR by one quartile, the odds ratio (OR) increased significantly for all five cardiometabolic diseases in both genders (p_trend  < 0.001). With regard to the highest versus the lowest quartile of VSR, the ORs for cardiometabolic diseases were significantly higher in women than in men. Restricted cubic splines showed that there were significant non-linear relationships between VSR and the risk of MAFLD, dyslipidemia, hyperglycemia, and hypertension in both genders (p for non-linearity <0.05). The risk was relatively flat until VSR reached 3.078 cm² /kg in men and 4.750 cm² /kg in women and started to increase rapidly afterwards. In men, however, the risk slowed down after the VSR value reached around 4 cm² /kg.

CONCLUSIONS

VSR was positively associated with cardiometabolic diseases regardless of gender. As VSR increased, the risk of cardiometabolic diseases was significantly higher in women than in men.

TRIAL REGISTRATION

www.chictr.org.cn (Registration number: ChiCTR2100044305).

Altered Adipocyte Cell Size Distribution Prior to Weight Loss in the R6/2 Model of Huntington's Disease

BACKGROUND

Metabolic alterations contribute to disease onset and prognosis of Huntington's disease (HD). Weight loss in the R6/2 mouse model of HD is a consistent feature, with onset in mid-to-late stage of disease.

OBJECTIVE

In the present study, we aimed to investigate molecular and functional changes in white adipose tissue (WAT) that occur at weight loss in R6/2 mice. We further elaborated on the effect of leptin-deficiency and early obesity in R6/2 mice.

METHODS

We performed analyses at 12 weeks of age; a time point that coincides with the start of weight loss in our R6/2 mouse colony. Gonadal (visceral) and inguinal (subcutaneous) WAT depot weights were monitored, as well as adipocyte size distribution. Response to isoprenaline-stimulated glycerol release and insulin-stimulated glucose uptake in adipocytes from gonadal WAT was assessed.

RESULTS

In R6/2 mice, WAT depot weights were comparable to wildtype (WT) mice, and the response to insulin and isoprenaline in gonadal adipocytes was unaltered. Leptin-deficient R6/2 mice exhibited distinct changes compared to leptin-deficient WT mice. At 12 weeks, female leptin-deficient R6/2 mice had reduced body weight accompanied by an increased proportion of smaller adipocytes, while in contrast; male mice displayed a shift towards larger adipocyte sizes without a significant body weight reduction at this timepoint.

CONCLUSIONS

We here show that there are early sex-specific changes in adipocyte cell size distribution in WAT of R6/2 mice and leptin-deficient R6/2 mice.

Sex and Gender and Allostatic Mechanisms of Cardiovascular Risk and Disease

Cardiovascular diseases are leading causes of mortality and morbidity in adults worldwide. Multiple studies suggest that there are clinically relevant sex differences in cardiovascular disease. Women and men differ substantially in terms of prevalence, presentation, management, and outcomes of cardiovascular disease. To date, however, little is known about why cardiovascular disease affects women and men differently. Because many studies do not differentiate the concept of sex and gender, it is sometimes difficult to discriminate sociocultural vs biological contributors that drive observed clinical differences. Female sex has some biological advantages in relation to cardiovascular disease, but many of these advantages seem to disappear as soon as women develop cardiovascular risk factors (eg, type 2 diabetes, hypertension, dyslipidemia). Furthermore, stress and allostatic load could play an important role in the relationship between sex/gender and cardiovascular diseases. In this narrative review, we argue that chronic stress and psychosocial factors might better encompass the patterns of allostatic load increases seen in women, while biological risk factors and unhealthy behaviours might be more important mechanisms that drive increased allostatic load in men. Indeed, men show allostatic load patterns that are more associated with impaired anthropometric, metabolic, and cardiovascular functioning and women have greater dysregulation in neuroendocrine and immune functioning. Thus gender-related factors might contribute to the pathogenesis of cardiovascular disease especially through stress mechanisms. It is important to continue to study the mechanisms by which gender influences chronic stress, because chronic stress could influence modifiable gendered factors to promote cardiovascular disease prevention.

Depot-specific adipose tissue modulation by SGLT2 inhibitors and GLP1 agonists mediates their cardioprotective effects in metabolic disease

Sodium-glucose transporter-2 inhibitors (SGLT-2i) and glucagon-like peptide 1 (GLP-1) receptor agonists are newer antidiabetic drug classes, which were recently shown to decrease cardiovascular (CV) morbidity and mortality in diabetic patients. CV benefits of these drugs could not be directly attributed to their blood glucose lowering capacity possibly implicating a pleotropic effect as a mediator of their impact on cardiovascular disease (CVD). Particularly, preclinical and clinical studies indicate that SGLT-2i(s) and GLP-1 receptor agonists are capable of differentially modulating distinct adipose pools reducing the accumulation of fat in some depots, promoting the healthy expansion of others, and/or enhancing their browning, leading to the suppression of the metabolically induced inflammatory processes. These changes are accompanied with improvements in markers of cardiac structure and injury, coronary and vascular endothelial healing and function, vascular remodeling, as well as reduction of atherogenesis. Here, through a summary of the available evidence, we bring forth our view that the observed CV benefit in response to SGLT-2i or GLP-1 agonists therapy might be driven by their ameliorative impact on adipose tissue inflammation.

Comparison of the role of alcohol consumption and qualitative abdominal fat on NAFLD and MAFLD in males and females

The clinical difference between nonalcoholic fatty liver disease (NAFLD) and metabolic-associated fatty liver disease (MAFLD) between the two sexes is unclear. This study aimed to determine the influences of alcohol consumption and qualitative abdominal fat between male and female patients with NAFLD and MAFLD. This cross-sectional study examined 11,766 participants who underwent health check-ups comparing lifestyle habits, biochemical features, and noninvasive liver fibrosis scores, between non-MAFLD and MAFLD groups. Furthermore, differences in alcohol consumption and qualitative abdominal fat were examined between male and female patients with NAFLD and MAFLD. The prevalence of metabolic dysregulation, ratio of visceral fat area to subcutaneous fat area, and noninvasive liver fibrosis scores were significantly higher in male patients with MAFLD than in those with NAFLD (p < 0.05), but these were not significantly different in female patients. Among male patients with an alcohol consumption of > 70 g/week, several noninvasive liver fibrosis scores were significantly higher in the MAFLD group than in the NAFLD group (all p < 0.05). The influences of alcohol consumption and qualitative abdominal fat on NAFLD and MAFLD were different between sexes. The development of liver fibrosis should be considered in male patients with MAFLD who exceed mild drinking.

Angiogenesis in adipose tissue and obesity

While most tissues exhibit their greatest growth during development, adipose tissue is capable of additional massive expansion in adults. Adipose tissue expandability is advantageous when temporarily storing fuel for use during fasting, but becomes pathological upon continuous food intake, leading to obesity and its many comorbidities. The dense vasculature of adipose tissue provides necessary oxygen and nutrients, and supports delivery of fuel to and from adipocytes under fed or fasting conditions. Moreover, the vasculature of adipose tissue comprises a major niche for multipotent progenitor cells, which give rise to new adipocytes and are necessary for tissue repair. Given the multiple, pivotal roles of the adipose tissue vasculature, impairments in angiogenic capacity may underlie obesity-associated diseases such as diabetes and cardiometabolic disease. Exciting new studies on the single-cell and single-nuclei composition of adipose tissues in mouse and humans are providing new insights into mechanisms of adipose tissue angiogenesis. Moreover, new modes of intercellular communication involving micro vesicle and exosome transfer of proteins, nucleic acids and organelles are also being recognized to play key roles. This review focuses on new insights on the cellular and signaling mechanisms underlying adipose tissue angiogenesis, and on their impact on obesity and its pathophysiological consequences.

Transcriptome and fatty-acid signatures of adipocyte hypertrophy and its non-invasive MR-based characterization in human adipose tissue

Background

The adipocyte-hypertrophy associated remodeling of fat cell function is considered causal for the development of metabolic disorders. A better understanding of transcriptome and fatty acid (FA) related alterations with adipocyte hypertrophy combined with less-invasive strategies for the detection of the latter can help to increase the prognostic and diagnostic value of adipocyte size and FA composition as markers for metabolic disease.

Methods

To clarify adipocyte-hypertrophy associated transcriptomic alterations, fat cell size was related to RNA-Seq data from white adipose tissue and size-separated adipocytes. The relationship between adipocyte size and adipose tissue FA composition as measured by GC-MS was investigated. MR spectroscopy (MRS) methods for clinical scanning were developed to characterize adipocyte size and FA composition in a fast and non-invasive manner.

Findings

With enlarged adipocyte size, substantial transcriptomic alterations of genes involved in mitochondrial function and FA metabolism were observed. Investigations of these two mechanisms revealed a reciprocal relationship between adipocyte size and estimated thermogenic adipocyte content as well as depot-specific correlations of adipocyte size and FA composition. MRS on a clinical scanner was suitable for the in-parallel assessment of adipose morphology and FA composition.

Interpretation

The current study provides a comprehensive overview of the adipocyte-hypertrophy associated transcriptomic and FA landscape in both subcutaneous and visceral adipose tissue. MRS represents a promising technique to translate the observed mechanistic, structural and functional changes in WAT with adipocyte hypertrophy into a clinical context for an improved phenotyping of WAT in the context of metabolic diseases.

Funding

Competence network for obesity (FKZ 42201GI1128), ERC (No 677661, ProFatMRI; No 875488, FatVirtualBiopsy), Else Kröner-Fresenius-Foundation.

Association of Body Mass Index and Abdominal Obesity with the Risk of Airflow Obstruction: National Health and Nutrition Examination Survey (NHANES) 2007-2012

This study aimed to explore the relationship between body mass index (BMI) and abdominal obesity and the risk of airflow obstruction, based on the data from the 2007-2012 National Health and Nutrition Survey (NHANES). Logistic regression was applied to assess the relationships between BMI or abdominal obesity and the risk of airflow obstruction by the fixed ratio method and the lower limit of normal (LLN) method. We further used the restricted cubic splines with 3 knots located at the 5th, 50th, and 95th percentiles of the distribution to evaluate the dose-response relationship. A total of 12,865 individuals aged 20-80 years old were included. In the fixed ratio method, underweight was positively correlated with the risk of airflow obstruction, and overweight and obesity were negatively correlated with the risk of airflow obstruction. In the LLN method, the results were consistent with the fixed ratio method. Abdominal obesity was positively associated with the risk of airflow obstruction only in the fixed ratio method (OR: 1.41, 95% CI: 1.04-1.90). There was an additive interaction between underweight and smoking on airflow obstruction in both methods. Abdominal obesity and smoking had additive interactions in the LLN method. Dose-response analysis indicated that there was a non-linear trend between BMI and the risk of airflow obstruction (P_{for nonlinearity} < 0.01). Our study suggested that underweight and abdominal obesity were associated with the increased risk of airflow obstruction, and overweight and general obesity were associated with the decreased risk of airflow obstruction.

Impact of training modes on fitness and body composition in women with obesity: A systematic review and meta-analysis

OBJECTIVE

This study aimed to assess the effectiveness of different exercise modalities and determine the optimal exercise prescription for improving cardiorespiratory fitness, body composition, and metabolic health of women with obesity.

METHODS

A systematic review of randomized controlled trials (RCTs) published between January 1988 and October 2020 was conducted. The RCTs were screened using the following inclusion criteria: 1) participants: women aged 18 to 65 years with BMI > 30 kg/m² and without comorbidities; 2) intervention: exercise; 3) comparison: non-intervention control; and 4) outcomes measures: cardiorespiratory fitness (maximal oxygen consumption), body composition (i.e., body weight, percentage body fat), and/or metabolic measures (i.e., blood pressure, cholesterol).

RESULTS

A total of 20 RCTs with a total of 2,062 participants were included. Although the results showed that any form of exercise was more effective than control, improvements in fitness and body composition were modest. Aerobic exercise (vigorous and moderate intensity) appeared most promising for improving fitness and body weight, whereas low-load resistance training resulted in the largest improvements in body fatness.

CONCLUSIONS

In women living with obesity, aerobic exercise was consistently effective in improving fitness and body composition. Although both resistance training and combined exercise interventions appear promising, more research is needed to evaluate their efficacy and determine an optimal exercise prescription for this population.

Adipose Tissue Inflammation and Cardiovascular Disease: An Update

PURPOSE OF REVIEW

The obesity epidemic is on the rise, and while it is well known that obesity is associated with an increase in cardiovascular risk factors such as type 2 diabetes mellitus, hypertension, and obstructive sleep apnea, recent data has highlighted that the degree and type of fat distribution may play a bigger role in the pathogenesis of cardiovascular disease (CVD) than body mass index (BMI) alone. We aim to review updated data on adipose tissue inflammation and distribution and CVD.

RECENT FINDINGS

We review the pathophysiology of inflammation secondary to adipose tissue, the association of obesity-related adipokines and CVD, and the differences and significance of brown versus white adipose tissue. We delve into the clinical manifestations of obesity-related inflammation in CVD. We discuss the available data on heterogeneity of adipose tissue-related inflammation with a focus on subcutaneous versus visceral adipose tissue, the differential pathophysiology, and clinical CVD manifestations of adipose tissue across sex, race, and ethnicity. Finally, we present the available data on lifestyle modification, medical, and surgical therapeutics on reduction of obesity-related inflammation. Obesity leads to a state of chronic inflammation which significantly increases the risk for CVD. More research is needed to develop non-invasive VAT quantification indices such as risk calculators which include variables such as sex, age, race, ethnicity, and VAT concentration, along with other well-known CVD risk factors in order to comprehensively determine risk of CVD in obese patients. Finally, pre-clinical biomarkers such as pro-inflammatory adipokines should be validated to estimate risk of CVD in obese patients.

Vitamin D status and obesity markers in older adults: results from West China Health and Aging Trends study

Backgrounds

Vitamin D deficiency and insufficiency in older adults seems to be common, but the prevalence estimates are lacking in West China. Previous studies suggested that low vitamin D status was associated with obesity. However, most of them evaluated obesity based on body mass index (BMI) and there are no studies at present exploring the association between vitamin D status and different obesity markers. The present study aims to investigate the prevalence of low vitamin D status and evaluate the association between the vitamin D status and different obesity markers among older adults in West China.

Methods

Data was based on the baseline of West China Health and Aging Trends study (WCHAT). All of the participants were older than 60 years old in the present study. Vitamin D status was based on laboratory data, and obesity markers were assessed by bioelectrical impedance analysis (BIA) using the InBody 770 analyzer. Multiple linear regression was performed to find the association between the vitamin D status and various obesity markers.

Results

The study included 2661 individuals (mean age: 67.7 ± 6.0 years; males: 41 %). The mean vitamin D level was 18.8 ± 6.3 ng/ml (range: 5 to 59 ng/ml); 5.2 % of participants had a sufficient level of vitamin D, 31.8 % had vitamin D insufficiency, and 63.0 % had vitamin D deficiency. Our results showed that vitamin D status was negatively associated with fat mass index (FMI), visceral fat area (VFA), and waist-hip ratio (WHR) in both sexes. Comparing to other obesity markers, WHR had the strongest correlation with vitamin D status in both sexes (β = -6.090, P = 0.046 in males; β = -11.253, P < 0.001 in females). No significant association was found between vitamin D status and BMI in males.

Conclusion

The prevalence of vitamin D insufficiency and deficiency among older adults in West China was high. Among the older adults in west China, WHR showed stronger association with vitamin D status and was better for the prediction of vitamin D insufficiency or deficiency in both sexes, compared to BMI.

Trial registration

Chinese Clinical Trial Registry: ChiCTR1800018895.

Inflammation-related plasma protein levels and association with adiposity measurements in young adults

Obesity-related inflammation is associated with cardiovascular, metabolic, and pulmonary diseases. The aim of this study was to demonstrate associations between adiposity measurements and levels of inflammation-related plasma proteins in a population of young adults. Subjects from a population-based birth cohort with a mean age of 22.5 years were included in the study population (n = 2074). Protein levels were analyzed using the Olink Proseek Multiplex Inflammation panel. Percentage body fat (%BF) and visceral fat rating (VFR) measurements were collected using Tanita MC 780 body composition monitor. Linear regression of standardized values was used to investigate associations. Potential effect modifications by sex and BMI category were assessed. Of 71 investigated proteins, 54 were significantly associated with all adiposity measurements [%BF, body mass index (BMI), VFR and waist circumference]. Among proteins associated with %BF, seven showed a larger or unique association in overweight/obese subjects and three showed a significant effect modification by sex. Fourteen proteins more strongly associated with VFR in females compared to males. Adipose-associated systemic inflammation was observed in this young adult population. Sex and adiposity localization influenced some of the associations. Our results highlight specific proteins as suitable biomarkers related to adiposity.

RNA-seq Characterization of Sex-Differences in Adipose Tissue of Obesity Affected Patients: Computational Analysis of Differentially Expressed Coding and Non-Coding RNAs

Obesity is a multifactorial disease presenting sex-related differences including adipocyte functions, sex hormone effects, genetics, and metabolic inflammation. These can influence individuals’ risk for metabolic dysfunctions, with an urgent need to perform sex-based analysis to improve prevention, treatment, and rehabilitation programs. This research work is aimed at characterizing the transcriptional differences present in subcutaneous adipose tissue (SAT) of five obesity affected men versus five obesity affected women, with an additional focus on the role of long non-coding RNAs. Through RNA-sequencing, we highlighted the presence of both coding and non-coding differentially expressed RNAs, and with numerous computational analyses we identified the processes in which these genes are implicated, along with their role in co-morbidities development. We report 51 differentially expressed transcripts, 32 of which were coding genes and 19 were non-coding. Using the WGCNA R package (Weighted Correlation Network Analysis, version 1.70-3), we describe the interactions between coding and non-coding RNAs, and the non-coding RNAs association with the insurgence of specific diseases, such as cancer development, neurodegenerative diseases, and schizophrenia. In conclusion, our work highlights a specific gender sex-related transcriptional signature in the SAT of obesity affected patients.

Synergizing Mouse and Human Studies to Understand the Heterogeneity of Obesity

Obesity is routinely considered as a single disease state, which drives a "one-size-fits-all" approach to treatment. We recently convened the first annual University of North Carolina Interdisciplinary Nutrition Sciences Symposium to discuss the heterogeneity of obesity and the need for translational science to advance understanding of this heterogeneity. The symposium aimed to advance scientific rigor in translational studies from animal to human models with the goal of identifying underlying mechanisms and treatments. In this review, we discuss fundamental gaps in knowledge of the heterogeneity of obesity ranging from cellular to population perspectives. We also advocate approaches to overcoming limitations in the field. Examples include the use of contemporary mouse genetic reference population models such as the Collaborative Cross and Diversity Outbred mice that effectively model human genetic diversity and the use of translational models that integrate -omics and computational approaches from pre-clinical to clinical models of obesity. Finally, we suggest best scientific practices to ensure strong rigor that will allow investigators to delineate the sources of heterogeneity in the population with obesity. Collectively, we propose that it is critical to think of obesity as a heterogeneous disease with complex mechanisms and etiologies, requiring unique prevention and treatment strategies tailored to the individual.

Lipofilling in Breast Oncological Surgery: A Safe Opportunity or Risk for Cancer Recurrence?

Lipofilling (LF) is a largely employed technique in reconstructive and esthetic breast surgery. Over the years, it has demonstrated to be extremely useful for treatment of soft tissue defects after demolitive or conservative breast cancer surgery and different procedures have been developed to improve the survival of transplanted fat graft. The regenerative potential of LF is attributed to the multipotent stem cells found in large quantity in adipose tissue. However, a growing body of pre-clinical evidence shows that adipocytes and adipose-derived stromal cells may have pro-tumorigenic potential. Despite no clear indication from clinical studies has demonstrated an increased risk of cancer recurrence upon LF, these observations challenge the oncologic safety of the procedure. This review aims to provide an updated overview of both the clinical and the pre-clinical indications to the suitability and safety of LF in breast oncological surgery. Cellular and molecular players in the crosstalk between adipose tissue and cancer are described, and heterogeneous contradictory results are discussed, highlighting that important issues still remain to be solved to get a clear understanding of LF safety in breast cancer patients.

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.

Sex Differences in the Incidence of Obesity-Related Gastrointestinal Cancer

Cancer is the second leading cause of death worldwide, with 9.6 million people estimated to have died of cancer in 2018. Excess body fat deposition is a risk factor for many types of cancer. Men and women exhibit differences in body fat distribution and energy homeostasis regulation. This systematic review aimed to understand why sex disparities in obesity are associated with sex differences in the incidence of gastrointestinal cancers. Cancers of the esophagus, liver, and colon are representative gastrointestinal cancers, and obesity is a convincing risk factor for their development. Numerous epidemiological studies have found sex differences in the incidence of esophageal, liver, and colorectal cancers. We suggest that these sexual disparities are partly explained by the availability of estrogens and other genetic factors regulating inflammation, cell growth, and apoptosis. Sex differences in gut microbiota composition may contribute to differences in the incidence and phenotype of colorectal cancer. To establish successful practices in personalized nutrition and medicine, one should be aware of the sex differences in the pathophysiology and associated mechanisms of cancer development.

X chromosome dosage of histone demethylase KDM5C determines sex differences in adiposity

Males and females differ in body composition and fat distribution. Using a mouse model that segregates gonadal sex (ovaries and testes) from chromosomal sex (XX and XY), we showed that XX chromosome complement in combination with a high-fat diet led to enhanced weight gain in the presence of male or female gonads. We identified the genomic dosage of Kdm5c, an X chromosome gene that escapes X chromosome inactivation, as a determinant of the X chromosome effect on adiposity. Modulating Kdm5c gene dosage in XX female mice to levels that are normally present in males resulted in reduced body weight, fat content, and food intake to a degree similar to that seen with altering the entire X chromosome dosage. In cultured preadipocytes, the levels of KDM5C histone demethylase influenced chromatin accessibility (ATAC-Seq), gene expression (RNA-Seq), and adipocyte differentiation. Both in vitro and in vivo, Kdm5c dosage influenced gene expression involved in extracellular matrix remodeling, which is critical for adipocyte differentiation and adipose tissue expansion. In humans, adipose tissue KDM5C mRNA levels and KDM5C genetic variants were associated with body mass. These studies demonstrate that the sex-dependent dosage of Kdm5c contributes to male/female differences in adipocyte biology and highlight X-escape genes as a critical component of female physiology.

BMP7 overexpression in adipose tissue induces white adipogenesis and improves insulin sensitivity in ob/ob mice

BACKGROUND/OBJECTIVES

During obesity, hypertrophic enlargement of white adipose tissue (WAT) promotes ectopic lipid deposition and development of insulin resistance. In contrast, WAT hyperplasia is associated with preservation of insulin sensitivity. The complex network of factors that regulates white adipogenesis is not fully understood. Bone morphogenic protein 7 (BMP7) can induce brown adipogenesis, but its role on white adipogenesis remains to be elucidated. Here, we assessed BMP7-mediated effects on white adipogenesis in ob/ob mice.

METHODS

BMP7 was overexpressed in either WAT or liver of ob/ob mice using adeno-associated viral (AAV) vectors. Analysis of gene expression, histological and morphometric alterations, and metabolites and hormones concentrations were carried out.

RESULTS

Overexpression of BMP7 in adipocytes of subcutaneous and visceral WAT increased fat mass, the proportion of small-size adipocytes and the expression of adipogenic and mature adipocyte genes, suggesting induction of adipogenesis irrespective of fat depot. These changes were associated with reduced hepatic steatosis and improved insulin sensitivity. In contrast, liver-specific overproduction of BMP7 did not promote WAT hyperplasia despite BMP7 circulating levels were similar to those achieved after genetic engineering of WAT.

CONCLUSIONS

This study unravels a new autocrine/paracrine role of BMP7 on white adipogenesis and highlights that BMP7 may modulate WAT plasticity and increase insulin sensitivity.

Causal associations between urinary sodium with body mass, shape and composition: a Mendelian randomization study

Observational studies have found associations between urinary sodium (UNa) with obesity, body shape and composition; but the findings may be biased by residual confounding. The objective of this two-sample Mendelian randomization (MR) study was to analyze their causal associations in both sex-combined and sex-specific models. Genome-wide association studies of UNa, body mass index (BMI), BMI-adjusted waist-to-hip ratio (WHR), body fat (BF) percentage and estimated glomerular filtration rate (eGFR) were identified. We initially extracted fifty SNPs associated with UNa at significance level of 5 × 10^–8, but further removed those SNPs with potential horizontal pleiotropy. Univariable and multivariable MR with adjustment for eGFR were performed. Inverse-variance weighted MR was performed as the primary analysis, with MR-Egger methods as sensitivity analysis. The potential bidirectional association between BMI and UNa was investigated. All exposure and outcomes were continuous, and the effect measure was regression coefficients (beta) and their 95% confidence intervals (95% CI). The total sample size was up to 322 154. UNa was causally associated with increased BMI in both men [eGFR-adjusted beta 0.443 (0.163–0.724)] and women [0.594 (0.333–0.855)]. UNa caused BF percentage increase in men [0.622 (0.268–0.976)] and women [0.334 (0.007–0.662)]. UNa significantly elevated BMI-adjusted WHR in men [0.321 (0.094–0.548)], but not in women [0.170 (− 0.052 to 0.391)]. Additionally, we found that BMI causally increased UNa [0.043 (0.023–0.063)]. UNa increased BMI and BF percentage. Salt intake affects male body shape by increasing BMI-adjusted WHR, but showed no effects on female body shape. The bidirectional association between BMI and UNa suggested that salt reduction measures and weight reduction measures should be implemented simultaneously to break the vicious cycle and gain more health benefits.

Sex differences in human adipose tissue gene expression and genetic regulation involve adipogenesis

Sex differences in adipose tissue distribution and function are associated with sex differences in cardiometabolic disease. While many studies have revealed sex differences in adipocyte cell signaling and physiology, there is a relative dearth of information regarding sex differences in transcript abundance and regulation. We investigated sex differences in subcutaneous adipose tissue transcriptional regulation using omic-scale data from ∼3000 geographically and ethnically diverse human samples. We identified 162 genes with robust sex differences in expression. Differentially expressed genes were implicated in oxidative phosphorylation and adipogenesis. We further determined that sex differences in gene expression levels could be related to sex differences in the genetics of gene expression regulation. Our analyses revealed sex-specific genetic associations, and this finding was replicated in a study of 98 inbred mouse strains. The genes under genetic regulation in human and mouse were enriched for oxidative phosphorylation and adipogenesis. Enrichment analysis showed that the associated genetic loci resided within binding motifs for adipogenic transcription factors (e.g., PPARG and EGR1). We demonstrated that sex differences in gene expression could be influenced by sex differences in genetic regulation for six genes (e.g., FADS1 and MAP1B). These genes exhibited dynamic expression patterns during adipogenesis and robust expression in mature human adipocytes. Our results support a role for adipogenesis-related genes in subcutaneous adipose tissue sex differences in the genetic and environmental regulation of gene expression.

Regulators of thymic stromal lymphopoietin production by human adipocytes

Thymic stromal lymphopoietin (TSLP) is a cytokine that is known to play a role in inflammatory conditions, especially asthma and atopic dermatitis. It is also recognized to be expressed in human adipose tissue. TSLP production from human adipocytes is stimulated by thyroid-stimulating hormone (TSH). This study aimed to identify TSH-dependent signaling routes that regulate TSLP, to determine if TSLP production is stimulated by other cytokines (IL-1β and TNF-α), and to examine if TSLP production depends on the adipose depot. Human abdominal differentiated adipocytes were stimulated with TSH, IL-1β, or TNF-α. Activation of cell signaling kinases was measured by phospho-immunoblot analysis, and TSLP in medium was assessed by ELISA. TSLP responses from abdominal subcutaneous and omental adipocytes were compared. TSH-stimulated TSLP secretion from subcutaneous adipocytes was enhanced by IBMX (raises cAMP levels) and was blocked by UO126 (inhibitor of MEK1/2-ERK1/2). TSLP secretion was stimulated by IL-1β and by TNF-α. SC-514 (inhibitor of IKKβ/NF-κB) only reduced the former. There was no effect of SB203580 (p38 MAPK inhibitor) or SP600125 (JNK inhibitor) on the stimulation by TSH, IL-1β or TNF-α. Interferon-γ inhibited TSLP responses to TSH, IL-1β, and TNF-α; IL-4 only blocked the response to TNFα. Intra-abdominal omental adipocytes also release TSLP in response to TSH, IL-1β, and TNF-α. We conclude TSLP is produced by human differentiated adipocytes derived from subcutaneous or omental depots in response to a variety of agonists. Further studies will be needed to understand what role it may play in adipose biology.

Identification of distinct transcriptome signatures of human adipose tissue from fifteen depots

The functional and metabolic characteristics of specific adipose tissue (AT) depots seem to be determined by intrinsic mechanisms. We performed a comprehensive transcriptome profiling of human AT from distinct fat depots to unravel their unique features potentially explaining molecular mechanisms underlying AT distribution and their contribution to health and disease. Post-mortem AT samples of five body donors from 15 anatomical locations were collected. Global mRNA expression was measured by Illumina® Human HT-12 v4 Expression BeadChips. Data were validated using qPCR and Western Blot in a subset of ATs from seven additional body donors. Buccal and heel AT clearly separated from the “classical” subcutaneous AT depots, and perirenal and epicardial AT were distinct from visceral depots. Gene-set enrichment analyses pointed to an inflammatory environment and insulin resistance particularly in the carotid sheath AT depot. Moreover, the epicardial fat transcriptome was enriched for genes involved in extracellular matrix remodeling, inflammation, immune signaling, coagulation, thrombosis, beigeing, and apoptosis. Interestingly, a striking downregulation of the expression of leptin receptor was found in AT from heel compared with all other AT depots. The distinct gene expression patterns are likely to define fat depot specific AT functions in metabolism, energy storage, immunity, body insulation or as cushions. Improved knowledge of the gene expression profiles of various fat depots may strongly benefit studies aimed at better understanding of the genetics and the pathophysiology of obesity and adverse body fat composition.

Distinct abdominal and gluteal adipose tissue transcriptome signatures are altered by exercise training in African women with obesity

The differential associations of adipose depots with metabolic risk during obesity have been proposed to be controlled by environmental and genetic factors. We evaluated the regional differences in transcriptome signatures between abdominal (aSAT) and gluteal subcutaneous adipose tissue (gSAT) in obese black South African women and tested the hypothesis that 12-week exercise training alters gene expression patterns in a depot-specific manner. Twelve young women performed 12-weeks of supervised aerobic and resistance training. Pre- and post-intervention measurements included peak oxygen consumption (VO_2peak), whole-body composition and unbiased gene expression analysis of SAT depots. VO_2peak increased, body weight decreased, and body fat distribution improved with exercise training (p < 0.05). The expression of 15 genes, mainly associated with embryonic development, differed between SAT depots at baseline, whereas 318 genes were differentially expressed post-training (p < 0.05). Four developmental genes were differentially expressed between these depots at both time points (HOXA5, DMRT2, DMRT3 and CSN1S1). Exercise training induced changes in the expression of genes associated with immune and inflammatory responses, and lipid metabolism in gSAT, and muscle-associated processes in aSAT. This study showed differences in developmental processes regulating SAT distribution and expandability of distinct depots, and depot-specific adaptation to exercise training in black South African women with obesity.

Regulatory T cells promote adipocyte beiging in subcutaneous adipose tissue

Regulatory T cells (Tregs) play essential roles in obesity and diabetes. Here, we report a role of Tregs in enhancing β3-adrenergic receptor agonist CL316243 (CL)-stimulated thermogenic program in subcutaneous adipose tissue (SAT), but not in visceral fat. CL treatment for 7 days increased SAT adipocyte beiging and thermogenic gene expression in male or female mice. Adoptive transfer of Tregs enhanced this CL activity. Such Treg activity lost in male epididymal white adipose tissue (eWAT) and female gonadal gWAT. Adipocyte culture yielded the same conclusion. Tregs enhanced the expression of CL-induced thermogenic genes in SAT from male and female mice. This activity of Tregs reduced or disappeared in adipocytes from eWAT or gWAT. Both CL and Tregs induced much higher UCP-1 (uncoupling protein-1) expression in SAT from females than that from males. A mechanistic study demonstrated a role of Tregs in suppressing the expression of M1 macrophage markers (Tnfa, Il6, iNos, Ip10) and promoting the expression of M2 macrophage markers (Mrc1, Arg1, Il10) in bone-marrow-derived macrophages or in SAT from male or female mice. In female mice with pre-established obesity, Treg adoptive transfer reduced the gWAT weight in 2 weeks. Together with CL treatment, Treg adoptive transfer reduced the SAT weight and further improved CL-induced glucose metabolism and insulin sensitivity in female obese mice, but did not affect CL-induced body weight loss in male or female obese mice. This study revealed a predominant role of Tregs in female mice in promoting adipocyte beiging and thermogenesis in SAT, in part by slanting M2 macrophage polarization.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Thigh Adipocyte Size is Inversely Related to Energy Intake and Respiratory Quotient in Healthy Women

OBJECTIVE

The relationship between adipocyte size and ad libitum energy intake has not been previously examined. This study hypothesized an inverse relationship between adipocyte size and daily energy intake (DEI).

METHODS

Seventy healthy adults (39 men and 31 women; BMI 30.0  [SD 6.3]) underwent dual-energy x-ray absorptiometry and subcutaneous fat biopsies from the abdomen and thigh. Osmium-fixed adipocytes were sized with a Coulter counter. Volunteers self-selected food from a vending machine paradigm as the only source of energy intake over 3 days as inpatients. Volunteers also had 24-hour respiratory quotient (RQ) measured in a whole-room indirect calorimeter.

RESULTS

In women, the large cell peak diameter of the thigh depot was greater than that of the abdominal depot (Δ = +15.8 μm; P < 0.0001). In women, thigh peak diameter was inversely associated with DEI (β = -264.7 kcal/d per 10-μm difference; P = 0.03) after adjusting for demographics and body composition. The thigh peak diameter in women was associated with 24-hour RQ (r = -0.47, P = 0.04) after adjusting for demographics, body composition, and 24-hour energy balance. These associations did not extend to men or the abdominal depot.

CONCLUSIONS

In women, thigh adipocyte size was associated with reduced DEI and 24-hour RQ, indicating a special role for thigh fat in women. This depot-specific sexual dimorphism indicates common regulation of energy intake and adipocyte size in the thigh region of women.

Sex-specific metabolic responses to 6 hours of fasting during the active phase in young mice

KEY POINTS

Night time/active phase food restriction for 6 h impaired glucose intolerance in young male and female mice. Females displayed increased capacity for lipogenesis and triglyceride storage in response to a short daily fast. Females had lower fasting insulin levels and an increased potential for utilizing fat for energy through β-oxidation compared to males. The need for the inclusion of both sexes, and the treatment of sex as an independent variable, is emphasized within the context of this fasting regime.

ABSTRACT

There is growing interest in understanding the mechanistic significance and benefits of fasting physiology in combating obesity. Increasing the fasting phase of a normal day can promote restoration and repair mechanisms that occur during the post-absorptive period. Most studies exploring the effect of restricting food access on mitigating obesity have done so with a large bias towards the use of male mice. Here, we disentangle the roles of sex, food intake and food withdrawal in the response to a short-term daily fasting intervention, in which food was removed for 6 h in the dark/active phase of young, 8-week-old mice. We showed that the removal of food during the dark phase impaired glucose tolerance in males and females, possibly due to the circadian disruption induced by this feeding protocol. Although both sexes demonstrated similar patterns of food intake, body composition and various metabolic markers, there were clear sex differences in the magnitude and extent of these responses. While females displayed enhanced capacity for lipogenesis and triglyceride storage, they also had low fasting insulin levels and an increased potential for utilizing available energy sources such as fat for energy through β-oxidation. Our results highlight the intrinsic biological and metabolic disparities between male and female mice, emphasizing the growing need for the inclusion of both sexes in scientific research. Furthermore, our results illustrate sex-specific metabolic pathways that regulate lipogenesis, obesity and overall metabolic health.

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.

Correlates of exposure to phenols, parabens, and triclocarban in the Study of Environment, Lifestyle and Fibroids

We performed a cross-sectional analysis to identify correlates of urinary concentrations of seven phenols (bisphenols A, F, and S; 2,4-dichlorophenol; 2,5-dichlorophenol; benzophenone-3; triclosan), triclocarban, and four parabens (butyl, ethyl, methyl, and propyl). We analyzed baseline data from 766 participants in the Study of Environment, Lifestyle, and Fibroids, a prospective cohort study of 1693 Black women aged 23-34 years residing in Detroit, Michigan (2010-2012). We collected data on demographic, behavioral, and anthropometric factors via telephone interviews, clinic visits, and self-administered questionnaires. For each biomarker, we used linear regression models to estimate mean differences in log-transformed, creatinine-corrected concentrations across factors of interest. Each biomarker was detected in >50% of participants. Median creatinine-corrected concentrations were the highest for methyl paraben (116.8 μg/g creatinine), propyl paraben (16.8 μg/g creatinine), and benzophenone-3 (13.4 μg/g creatinine). Variables most strongly associated with biomarker concentrations included season of urine collection, education, and body mass index (BMI). BMI was positively associated with bisphenol A and S and triclocarban concentrations and inversely associated with butyl and methyl paraben concentrations. In this cohort of Black women, exposure to phenols, parabens, and triclocarban was prevalent and several factors were associated with biomarker concentrations.