Abdominal superficial subcutaneous fat: a putative distinct protective fat subdepot in type 2 diabetes

Female-specific pancreatic cancer survival from CT imaging of visceral fat implicates glutathione metabolism in solid tumors

RATIONALE AND OBJECTIVES

To identify if body composition, assessed with preoperative CT-based visceral fat ratio quantification as well as tumor metabolic gene expression, predicts sex-dependent overall survival (OS) in patients with pancreatic ductal adenocarcinoma (PDAC).

MATERIALS AND METHODS

This was a retrospective analysis of preoperative CT in 98 male and 107 female patients with PDAC. Relative visceral fat (rVFA; visceral fat normalized to total fat) was measured automatically using software and corrected manually. Median and optimized rVFA thresholds were determined according to published methods. Kaplan Meier and log-rank tests were used to estimate OS. Multivariate models were developed to identify interactions between sex, rVFA, and OS. Unsupervised gene expression analysis of PDAC tumors from The Cancer Genome Atlas (TCGA) was performed to identify metabolic pathways with similar survival patterns to rVFA.

RESULTS

Optimized preoperative rVFA threshold of 38.9% predicted significantly different OS in females with a median OS of 15 months (above threshold) vs 24 months (below threshold; p = 0.004). No significant threshold was identified in males. This female-specific significance was independent of age, stage, and presence of chronic pancreatitis (p = 0.02). Tumor gene expression analysis identified female-specific stratification from a five-gene signature of glutathione S-transferases. This was observed for PDAC as well as clear cell renal carcinoma and glioblastoma.

CONCLUSION

CT-based assessments of visceral fat can predict pancreatic cancer OS in females. Glutathione S-transferase expression in tumors predicts female-specific OS in a similar fashion.

Sex-specific association of visceral and subcutaneous adipose tissue volumes with systemic inflammation and innate immune cells in people living with obesity

BACKGROUND AND AIMS

Obesity predisposes to metabolic and cardiovascular diseases. Adipose tissue inflammation and systemic inflammation contribute to these complications. There are strong sex differences in adipose tissue distribution and in systemic inflammation. Women have more subcutaneous adipose tissue (SAT) and less visceral adipose tissue (VAT) than men. We explored the sex differences in the association between the different adipose compartments and inflammatory markers that are important in cardiometabolic disease pathophysiology.

METHODS

Single-center observational cohort study with 302 individuals with a BMI ≥ 27 kg/m2. We were unable to acquire MRI data from seven individuals and from another 18 the MRI data were not usable, resulting in 277 people (155 men, 122 women), aged 55-81 years.

INTERVENTION

We performed the following measurements: abdominal magnetic resonance imaging to measure VAT, and SAT (deep and superficial) volumes; circulating leukocyte counts and cytokine production capacity of peripheral blood mononuclear cells (PBMCs), circulating cytokines, adipokines, and targeted proteomics; abdominal sSAT biopsies for histology and gene expression.

RESULTS

Only in women, (s)SAT volume was associated with circulating leukocytes, monocytes, and neutrophils. Circulating IL-6 and IL-18BP were associated with SAT volume in women and VAT in men. Several circulating proteins, including monocyte-colony-stimulating factor 1 and hepatocyte growth factor, are associated with sSAT in women and VAT in men. Only in women, SAT volume is associated with SAT expression of inflammatory proteins, including leptin, CD68, TNFα and IL-1α.

CONCLUSION

In women living with obesity, abdominal SAT volume, especially sSAT, is associated with circulating leukocytes and inflammatory proteins. In men, these parameters mainly show associations with VAT volume. This could be because only in women, sSAT volume is associated with sSAT expression of inflammatory proteins. These findings underscore that future research on adipose tissue in relation to cardiometabolic and cardiovascular disease should take sex differences into account.

Mimicking lipolytic, adipogenic, and secretory capacities of human subcutaneous adipose tissue by spheroids from distinct subpopulations of adipose stromal/stem cells

Background: Adipose tissue engineering may provide 3D models for the understanding of diseases such as obesity and type II diabetes. Recently, distinct adipose stem/stromal cell (ASC) subpopulations were identified from subcutaneous adipose tissue (SAT): superficial (sSAT), deep (dSAT), and the superficial retinacula cutis (sRC). This study aimed to test these subpopulations ASCs in 3D spheroid culture induced for adipogenesis under a pro-inflammatory stimulus with lipopolysaccharide (LPS). Methods: The samples of abdominal human subcutaneous adipose tissue were obtained during plastic aesthetic surgery (Protocol 145/09). Results: ASC spheroids showed high response to adipogenic induction in sSAT. All ASC spheroids increased their capacity to lipolysis under LPS. However, spheroids from dSAT were higher than from sSAT (p = 0.0045) and sRC (p = 0.0005). Newly formed spheroids and spheroids under LPS stimulus from sSAT showed the highest levels of fatty acid-binding protein 4 (FABP4) and CCAAT/enhancer-binding protein-α (C/EBPα) mRNA expression compared with dSAT and sRC (p < 0.0001). ASC spheroids from sRC showed the highest synthesis of angiogenic cytokines such as vascular endothelial growth factor (VEGF) compared with dSAT (p < 0.0228). Under LPS stimulus, ASC spheroids from sRC showed the highest synthesis of pro-inflammatory cytokines such as IL-6 compared with dSAT (p < 0.0092). Conclusion: Distinct physiological properties of SAT can be recapitulated in ASC spheroids. In summary, the ASC spheroid from dSAT showed the greatest lipolytic capacity, from sSAT the greatest adipogenic induction, and sRC showed greater secretory capacity when compared to the dSAT. Together, all these capacities form a true mimicry of SAT and hold the potential to contribute for a deeper understanding of cellular and molecular mechanisms in healthy and unhealthy adipose tissue scenarios or in response to pharmacological interventions.

Cutaneous changes in diabetic patients: Primed for aberrant healing?

Cutaneous manifestations affect most patients with diabetes mellitus, clinically presenting with numerous dermatologic diseases from xerosis to diabetic foot ulcers (DFUs). Skin conditions not only impose a significantly impaired quality of life on individuals with diabetes but also predispose patients to further complications. Knowledge of cutaneous biology and the wound healing process under diabetic conditions is largely limited to animal models, and studies focusing on biology of the human condition of DFUs remain limited. In this review, we discuss the critical molecular, cellular, and structural changes to the skin in the hyperglycaemic and insulin-resistant environment of diabetes with a focus specifically on human-derived data. Elucidating the breadth of the cutaneous manifestations coupled with effective diabetes management is important for improving patient quality of life and averting future complications including wound healing disorders.

Analysis of Superficial Subcutaneous Fat Camper's and Scarpa's Fascia in a United States Cohort

Together, the Camper's and Scarpa's fasciae form the superficial fat layer of the abdominal wall. Though they have clinical and surgical relevance, little is known about their role in body composition across diverse patient populations. This study aimed to determine the relationship between patient characteristics, including sex and body mass index, and the distribution of Camper's and Scarpa's fascial layers in the abdominal wall. A total of 458 patients' abdominal CT examinations were segmented via CoreSlicer 1.0 to determine the surface area of each patient's Camper's, Scarpa's, and visceral fascia layers. The reproducibility of segmentation was corroborated by an inter-rater analysis of segmented data for 20 randomly chosen patients divided between three study investigators. Pearson correlation and Student's t-test analyses were performed to characterize the relationship between fascia distribution and demographic factors. The ratios of Camper's fascia, both as a proportion of superficial fat (r = -0.44 and p < 0.0001) and as a proportion of total body fat (r = -0.34 and p < 0.0001), showed statistically significant negative correlations with BMI. In contrast, the ratios of Scarpa's fascia, both as a proportion of superficial fat (r = 0.44 and p < 0.0001) and as a proportion of total body fat (r = 0.41 and p < 0.0001), exhibited statistically significant positive correlations with BMI. Between sexes, the females had a higher ratio of Scarpa's facia to total body fat compared to the males (36.9% vs. 31% and p < 0.0001). The ICC values for the visceral fat, Scarpa fascia, and Camper fascia were 0.995, 0.991, and 0.995, respectively, which were all within the 'almost perfect' range (ICC = 0.81-1.00). These findings contribute novel insights by revealing that as BMI increases the proportion of Camper's fascia decreases, while the ratio of Scarpa's fascia increases. Such insights expand the scope of body composition studies, which typically focus solely on superficial and visceral fat ratios.

Specific Features of Stromal Cells Isolated from the Two Layers of Subcutaneous Adipose Tissue: Roles of Their Secretion on Angiogenesis and Neurogenesis

Human-adipose-tissue-derived mesenchymal stromal cells (AD-MSCs) are currently being tested as autologous-cell-based therapies for use in tissue healing and regeneration. Recent studies have also demonstrated that AD-MSC-derived exosomes contribute to tissue repair and peripheral nerve regeneration. Subcutaneous abdominal adipose tissue (AAT) is divided into two layers: the superficial layer (sAAT) and the deep layer (dAAT). However, it is unclear whether there are particular characteristics of each layer in terms of AD-MSC regenerative potential. Using AD-MSCs purified and characterized from three abdominoplasties, we compared their secretomes and exosome functions to identify which layer may be most suitable as a source for cell therapy. Phenotypical analysis of the AD-MSCs containing stromal vascular fraction did not reveal any difference between the two layers. The AD-MSC secretomes showed a very similar pattern of cytokine content and both layers were able to release exosomes with identical characteristics. However, compared to the secretome, the released exosomes showed better biological properties. Interestingly, dAAT exosomes appeared to be more effective on neuromodulation, whereas neither sAAT nor dAAT-derived exosomes had significant effects on endothelial function. It thus appears that AD-MSC-derived exosomes from the two abdominal adipose tissue layers possess different features for cell therapy.

Unraveling White Adipose Tissue Heterogeneity and Obesity by Adipose Stem/Stromal Cell Biology and 3D Culture Models

The immune and endocrine dysfunctions of white adipose tissue are a hallmark of metabolic disorders such as obesity and type 2 diabetes. In humans, white adipose tissue comprises distinct depots broadly distributed under the skin (hypodermis) and as internal depots (visceral). Depot-specific ASCs could account for visceral and subcutaneous adipose tissue properties, by regulating adipogenesis and immunomodulation. More importantly, visceral and subcutaneous depots account for distinct contributions to obesity and its metabolic comorbidities. Recently, distinct ASCs subpopulations were also described in subcutaneous adipose tissue. Interestingly, the superficial layer closer to the dermis shows hyperplastic and angiogenic capacities, whereas the deep layer is considered as having inflammatory properties similar to visceral. The aim of this focus review is to bring the light of recent discoveries into white adipose tissue heterogeneity together with the biology of distinct ASCs subpopulations and to explore adipose tissue 3D models revealing their advantages, disadvantages, and contributions to elucidate the role of ASCs in obesity development. Recent advances in adipose tissue organoids opened an avenue of possibilities to recreate the main cellular and molecular events of obesity leading to a deep understanding of this inflammatory disease besides contributing to drug discovery. Furthermore, 3D organ-on-a-chip will add reproducibility to these adipose tissue models contributing to their translation to the pharmaceutical industry.

Comparison of therapeutic effects of mesenchymal stem cells derived from superficial and deep subcutaneous adipose tissues

BACKGROUND

Fibrosis is a common histological feature in the process from chronic organ injury to organ failure. Chronic tissue injury causes inflammatory cell infiltration into the injured tissue. The persistence of this inflammatory cell infiltration leads to fibrosis and organ failure. Adipose-derived mesenchymal stem cells (ASCs) have received much attention as a regenerative therapeutic tool to prevent progression from organ injury to failure. Subcutaneous abdominal adipose tissue is divided into superficial and deep layers by a superficial fascia. Adipose tissue easily collected by liposuction is usually obtained from a deep layer, so ASCs derived from a deep layer are generally used for regenerative medicine. However, no research has been conducted to investigate differences in the therapeutic effects of ASCs from the superficial and deep layers (Sup-ASCs and Deep-ASCs, respectively). Therefore, we compared the therapeutic potencies of Sup-ASCs and Deep-ASCs.

METHODS

ASCs were isolated from superficial and deep subcutaneous abdominal adipose tissues collected from patients who underwent breast reconstruction. We first compared cell characteristics, such as morphology, cell proliferation, cell surface markers, adipogenic and osteogenic differentiation, cell senescence markers, and expression of coagulation and anticoagulant factors between Sup-ASCs and Deep-ASCs. Furthermore, we compared their ability to promote polarization of M2 macrophages and to inhibit transforming growth factor (TGF)-β/Smad signaling using THP-1 cells and TGF-β1 stimulated HK-2 cells incubated with conditioned media from Sup-ASCs or Deep-ASCs. In in vivo experiments, after renal ischemia-reperfusion injury (IRI) procedure, Sup-ASCs or Deep-ASCs were injected through the abdominal aorta. At 21 days post-injection, the rats were sacrificed and their left kidneys were collected to evaluate fibrosis. Finally, we performed RNA-sequencing analysis of Sup-ASCs and Deep-ASCs.

RESULTS

Sup-ASCs had greater proliferation and adipogenic differentiation compared with Deep-ASCs, whereas both ASC types had similar morphology, cell surface markers, senescence markers, and expression of coagulation and anticoagulant factors. Conditioned media from Sup-ASCs and Deep-ASCs equally promoted polarization of M2 macrophages and suppressed TGF-β/Smad signaling. Moreover, administration of Sup-ASCs and Deep-ASCs equally ameliorated renal fibrosis induced by IRI in rats. RNA-sequencing analysis revealed no significant difference in the expression of genes involved in anti-inflammatory and anti-fibrotic effects between Sup-ASCs and Deep-ASCs.

CONCLUSIONS

These results indicate that both Sup-ASCs and Deep-ASCs can be used effectively and safely as an intravascular ASC therapy for organ injury.

Imaging modalities for measuring body composition in patients with cancer: opportunities and challenges

Body composition assessment (ie, the measurement of muscle and adiposity) impacts several cancer-related outcomes including treatment-related toxicities, treatment responses, complications, and prognosis. Traditional modalities for body composition measurement include body mass index, body circumference, skinfold thickness, and bioelectrical impedance analysis; advanced imaging modalities include dual energy x-ray absorptiometry, computerized tomography, magnetic resonance imaging, and positron emission tomography. Each modality has its advantages and disadvantages, thus requiring an individualized approach in identifying the most appropriate measure for specific clinical or research situations. Advancements in imaging approaches have led to an abundance of available data, however, the lack of standardized thresholds for classification of abnormal muscle mass or adiposity has been a barrier to adopting these measurements widely in research and clinical care. In this review, we discuss the different modalities in detail and provide guidance on their unique opportunities and challenges.

The effect of high-polyphenol Mediterranean diet on visceral adiposity: the DIRECT PLUS randomized controlled trial

BACKGROUND

Mediterranean (MED) diet is a rich source of polyphenols, which benefit adiposity by several mechanisms. We explored the effect of the green-MED diet, twice fortified in dietary polyphenols and lower in red/processed meat, on visceral adipose tissue (VAT).

METHODS

In the 18-month Dietary Intervention Randomized Controlled Trial PoLyphenols UnproceSsed (DIRECT-PLUS) weight-loss trial, 294 participants were randomized to (A) healthy dietary guidelines (HDG), (B) MED, or (C) green-MED diets, all combined with physical activity. Both isocaloric MED groups consumed 28 g/day of walnuts (+ 440 mg/day polyphenols). The green-MED group further consumed green tea (3-4 cups/day) and Wolffia globosa (duckweed strain) plant green shake (100 g frozen cubes/day) (+ 800mg/day polyphenols) and reduced red meat intake. We used magnetic resonance imaging (MRI) to quantify the abdominal adipose tissues.

RESULTS

Participants (age = 51 years; 88% men; body mass index = 31.2 kg/m²; 29% VAT) had an 89.8% retention rate and 79.3% completed eligible MRIs. While both MED diets reached similar moderate weight (MED: - 2.7%, green-MED: - 3.9%) and waist circumference (MED: - 4.7%, green-MED: - 5.7%) loss, the green-MED dieters doubled the VAT loss (HDG: - 4.2%, MED: - 6.0%, green-MED: - 14.1%; p < 0.05, independent of age, sex, waist circumference, or weight loss). Higher dietary consumption of green tea, walnuts, and Wolffia globosa; lower red meat intake; higher total plasma polyphenols (mainly hippuric acid), and elevated urine urolithin A polyphenol were significantly related to greater VAT loss (p < 0.05, multivariate models).

CONCLUSIONS

A green-MED diet, enriched with plant-based polyphenols and lower in red/processed meat, may be a potent intervention to promote visceral adiposity regression.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT03020186.

Noninvasive NMR/MRS Metabolic Parameters to Evaluate Metabolic Syndrome in Rats

(1) Background: Ectopic fat deposition and its effects, metabolic syndrome, have been significantly correlated to lifestyle and caloric consumption. There is no specific noninvasive evaluation tool being used in order to establish clinical markers for tracing the metabolic pathway implicated in obesity-related abnormalities that occur in the body as a result of a high-fat diet (HFD). The purpose of this work is to investigate in vivo ectopic fat distribution and in vitro metabolite profiles given by HFDs, as well as how they are inter-related, in order to find surrogate metabolic biomarkers in the development of metabolic syndrome utilizing noninvasive approaches. (2) Methods: Male Wistar rats were divided into a standard normal chow diet, ND group, and HFD group. After 16 weeks of different diet administration, blood samples were collected for proton nuclear magnetic resonance (¹H NMR) and biochemical analysis. Magnetic resonance imaging/proton magnetic resonance spectroscopy (MRI/¹H MRS) was performed on the abdomen, liver, and psoas muscle of the rats. (3) Results: Visceral fat showed the strongest relationship with blood cholesterol. Although liver fat content (LFC) was not associated with any biophysical profiles, it had the highest correlation with metabolites such as (-CH₂)_n very-low-density lipoprotein/low-density lipoprotein (VLDL/LDL), lactate, and N-acetyl glycoprotein of serum ¹H NMR. HFD showed no obvious influence on muscle fat accumulation. Acetoacetate, N-acetyl glycoprotein, lactate, (-CH₂)_n VLDL/LDL, and valine were the five possible metabolic biomarkers used to differentiate HFD from ND in the present study. (4) Conclusions: Our study has validated the influence of long-term HFD-induced ectopic fat on body metabolism as well as the metabolic profile deterioration both in vivo and in vitro.

Environmental determinants of human milk composition in relation to health outcomes

Humans are exposed to environmental factors at every stage of life including infancy. The aim of this mini-review was to present a narrative of environmental factors influencing human milk composition. Current literature shows lactation is a dynamic process and is responsive to multiple environmental challenges including geographical location, lifestyle, persistent pollutants and maternal factors (ethnicity, diet, stress, allergy and adiposity) that may influence human milk composition in a synergistic manner and should be considered in order to improve infant and maternal outcomes on a populations scale. Further interventional studies on larger international cohorts are needed to elucidate these complex relationships. Lactating women should aim for a healthy lifestyle and maintain a healthy body composition prior to and throughout the reproductive period, including during lactation.

Human Milk Macronutrients and Bioactive Molecules and Development of Regional Fat Depots in Western Australian Infants during the First 12 Months of Lactation

We investigated associations between intakes of human milk (HM) components (macronutrients and biologically active molecules) and regional fat depots development in healthy term infants (n = 20) across the first year of lactation. Infant limb (mid-arm and mid-thigh) lean and fat areas were assessed by ultrasound imaging at 2, 5, 9 and 12 months of age. Concentrations of HM total protein, whey protein, casein, adiponectin, leptin, lysozyme, lactoferrin, secretory IGA, total carbohydrates, lactose, HM oligosaccharides (total HMO, calculated) and infant 24-h milk intake were measured, and infant calculated daily intakes (CDI) of HM components were determined. This pilot study shows higher 24-h milk intake was associated with a larger mid-arm fat area (p = 0.024), higher breastfeeding frequency was associated with larger mid-arm (p = 0.008) and mid-thigh (p < 0.001) fat areas. Lysozyme (p = 0.001) and HMO CDI (p = 0.004) were time-dependently associated with the mid-arm fat area. Intakes of HM components and breastfeeding parameters may modulate infant limb fat depots development during the first year of age and potentially promote favorable developmental programming of infant body composition; however, further studies are needed to confirm these findings.

Diet-induced Fasting Ghrelin Elevation Reflects the Recovery of Insulin Sensitivity and Visceral Adiposity Regression

CONTEXT

Lower fasting ghrelin levels (FGL) are associated with obesity and metabolic syndrome.

OBJECTIVE

We aimed to explore the dynamics of FGL during weight loss and its metabolic and adiposity-related manifestations beyond weight loss.

METHODS

This was a secondary analysis of a clinical trial that randomized participants with abdominal obesity/dyslipidemia to 1 of 3 diets: healthy dietary guidelines (HDG), Mediterranean diet (MED), or green-MED diet, all combined with physical activity (PA). Both MED diets were similarly hypocaloric and included 28 g/day walnuts. The green-MED group further consumed green tea (3-4 cups/day) and a Wolffia globosa (Mankai) plant green shake. We measured FGL and quantified body fat depots by magnetic resonance imaging at baseline and after 18 months.

RESULTS

Among 294 participants (body mass index = 31.3 kg/m2; FGL = 504 ± 208 pg/mL; retention rate = 89.8%), lower FGL was associated with unfavorable cardiometabolic parameters such as higher visceral adipose tissue (VAT), intrahepatic fat, leptin, and blood pressure (P < 0.05 for all; multivariate models). The ∆FGL18-month differed between men (+7.3 ± 26.6%) and women (-9.2% ± 21.3%; P = 0.001). After 18 months of moderate and similar weight loss among the MED groups, FGL increased by 1.3%, 5.4%, and 10.5% in HDG, MED, and green-MED groups, respectively (P = 0.03 for green-MED vs HDG); sex-stratified analysis revealed similar changes in men only. Among men, FGL18-month elevation was associated with favorable changes in insulin resistance profile and VAT regression, after adjusting for relative weight loss (HbA1c: r = -0.216; homeostatic model of insulin resistance: r = -0.154; HDL-c: r = 0.147; VAT: r = -0.221; P < 0.05 for all). Insulin resistance and VAT remained inversely related with FGL elevation beyond that explained by weight loss (residual regression analyses; P < 0.05).

CONCLUSION

Diet-induced FGL elevation may reflect insulin sensitivity recovery and VAT regression beyond weight loss, specifically among men. Green-MED diet is associated with greater FGL elevation.

Assessing Obesity-Related Adipose Tissue Disease (OrAD) to Improve Precision Medicine for Patients Living With Obesity

Obesity is a heterogenous condition that affects the life and health of patients to different degrees and in different ways. Yet, most approaches to treat obesity are not currently prescribed, at least in a systematic manner, based on individual obesity sub-phenotypes or specifically-predicted health risks. Adipose tissue is one of the most evidently affected tissues in obesity. The degree of adipose tissue changes - "adiposopathy", or as we propose to relate to herein as Obesity-related Adipose tissue Disease (OrAD), correspond, at least cross-sectionally, to the extent of obesity-related complications inflicted on an individual patient. This potentially provides an opportunity to better personalize anti-obesity management by utilizing the information that can be retrieved by assessing OrAD. This review article will summarize current knowledge on histopathological OrAD features which, beyond cross-sectional analyses, had been shown to predict future obesity-related endpoints and/or the response to specific anti-obesity interventions. In particular, the review explores adipocyte cell size, adipose tissue inflammation, and fibrosis. Rather than highly-specialized methods, we emphasize standard pathology laboratory approaches to assess OrAD, which are readily-available in most clinical settings. We then discuss how OrAD assessment can be streamlined in the obesity/weight-management clinic. We propose that current studies provide sufficient evidence to inspire concerted efforts to better explore the possibility of predicting obesity related clinical endpoints and response to interventions by histological OrAD assessment, in the quest to improve precision medicine in obesity.

The Effect of Weight-Loss Interventions on Cervical and Chin Subcutaneous Fat Depots; the CENTRAL Randomized Controlled Trial

Accumulation of cervical and chin subcutaneous adipose tissues (SAT) represent known phenotypes of obesity. We aimed to evaluate the sensitivity of these fat storages to long-term weight-loss directed lifestyle-intervention and to assess their relations to bodily-adiposity, insulin-resistance, and cardiometabolic risk; We randomly assigned 278 participants with abdominal-obesity/dyslipidemia to low-fat or Mediterranean/low-carbohydrate diets +/- physical-activity. All participants underwent an 18 month whole-body magnetic resonance imaging follow-up, from which we assessed cervical and chin SAT-areas; Participants (age = 48 years; 90% men; body-mass-index = 30.9 kg/m²) had an 18-month adherence-rate of 86%. Cervical-SAT and chin-SAT decreased after 6-months (-13.1% and -5.3%, respectively, p < 0.001). After 18-months only cervical-SAT remained decreased compared to baseline (-5%, p < 0.001). Cervical and chin-SAT 18-month changes were associated with changes in weight (r = 0.70, r = 0.66 respectively; <0.001 for both) and visceral-adipose-tissue (VAT; r = 0.35, r = 0.42 respectively; <0.001 for both). After adjustment to VAT, waist-circumference, or weight-changes, chin-SAT 18-month reduction was associated with favorable changes in fasting-glucose (β = 0.10; p = 0.05), HbA1c (β = 0.12; p = 0.03), and homeostasis-model-assessment-of-insulin-resistance (β = 0.12; p = 0.03). Cervical-SAT 18-month reduction was associated with decreased triglycerides (β = 0.16; p = 0.02) and leptin (β = 0.19; p = 0.01) independent of VAT; Cervical and chin-SATs are dynamic fat depots that correspond with weight-loss and are associated with changes in cardiometabolic profile. In long-term, chin-SAT displays a larger rebound compared with cervical-SAT. Chin-SAT accumulation is associated with in insulin-resistance, independent of central obesity. (ClinicalTrials identifier NCT01530724).

Transcriptome-Based Analysis Reveals Therapeutic Effects of Resveratrol on Endometriosis in aRat Model

Introduction

Endometriosis (EMs) is associated with severe chronic pelvic pain and infertility and the development of improved EMs treatment options is an ongoing focus. In this study, we investigated the effects of resveratrol on EMs and analyzed transcriptional changes in the lesions of model rats before and after resveratrol treatment.

Methods

We established arat model of endometriosis through the trans-implantation of endometrial fragments to the peritoneal wall and then used resveratrol as treatment. We then analyzed the results using RNA sequencing of the lesion tissues of each of the model rats before resveratrol treatment and the reduced lesion tissues after the treatment. Examinations of anatomy, biochemistry, immunohistochemical staining and flow cytometry examinations were also conducted. Other trans-implanted rats were also given sham treatments as sham-treatment control and other untrans-implanted rats served as sham-operation controls.

Results

In addition to the obvious lesions observed in the model rats, there were significant differences in the glucose tolerance, macrophage M1/M2 polarization, and adipocyte sizes between the treated model rats and sham (control) rats. Resveratrol treatment in the model rats showed significant efficacy and positive therapeutic effect. Transcriptional analysis showed that the effects of resveratrol on the endometriosis model rats were manifested by alterations in the PPAR, insulin resistance, MAPK and PI3K/Akt signaling pathways. Correspondingly, changes in PPARγ activation, M1/M2 polarization and lipid metabolism were also detected after resveratrol treatment.

Discussion

Our study revealed that resveratrol treatment displayed efficient therapeutic effects for EMs model rats, probably through its important roles in anti-inflammation, immunoregulation and lipid-related metabolism regulation.

Automated Segmentation of Visceral, Deep Subcutaneous, and Superficial Subcutaneous Adipose Tissue Volumes in MRI of Neonates and Young Children

Purpose

To develop and evaluate an automated segmentation method for accurate quantification of abdominal adipose tissue (AAT) depots (superficial subcutaneous adipose tissue [SSAT], deep subcutaneous adipose tissue [DSAT], and visceral adipose tissue [VAT]) in neonates and young children.

Materials and Methods

This was a secondary analysis of prospectively collected data, which used abdominal MRI data from Growing Up in Singapore Towards healthy Outcomes, or GUSTO, a longitudinal mother-offspring cohort, to train and evaluate a convolutional neural network for volumetric AAT segmentation. The data comprised imaging volumes of 333 neonates obtained at early infancy (age ≤2 weeks, 180 male neonates) and 755 children aged either 4.5 years (n = 316, 150 male children) or 6 years (n = 439, 219 male children). The network was trained on images of 761 randomly selected volumes (neonates and children combined) and evaluated on 100 neonatal volumes and 227 child volumes by using 10-fold validation. Automated segmentations were compared with expert-generated manual segmentation. Segmentation performance was assessed using Dice scores.

Results

When the model was tested on the test datasets across the 10 folds, the model had strong agreement with the ground truth for all testing sets, with mean Dice similarity scores for SSAT, DSAT, and VAT, respectively, of 0.960, 0.909, and 0.872 in neonates and 0.944, 0.851, and 0.960 in children. The model generalized well to different body sizes and ages and to all abdominal levels.

Conclusion

The proposed segmentation approach provided accurate automated volumetric assessment of AAT compartments on MR images of neonates and children.Keywords Pediatrics, Deep Learning, Convolutional Neural Networks, Water-Fat MRI, Image Segmentation, Deep and Superficial Subcutaneous Adipose Tissue, Visceral Adipose TissueClinical trial registration no. NCT01174875 Supplemental material is available for this article. © RSNA, 2021.

Advanced Molecular Imaging (MRI/MRS/1H NMR) for Metabolic Information in Young Adults with Health Risk Obesity

BACKGROUND

Obesity or being overweight is a medical condition of abnormal body fat accumulation which is associated with a higher risk of developing metabolic syndrome. The distinct body fat depots on specific parts of the anatomy have unique metabolic properties and different types of regional excessive fat distribution can be a disease hazard. The aim of this study was to identify the metabolome and molecular imaging phenotypes among a young adult population.

METHODS

The amount and distribution of fat and lipid metabolites profile in the abdomen, liver, and calf muscles of 46 normal weight, 17 overweight, and 13 obese participants were acquired using MRI and MR spectroscopy (MRS), respectively. The serum metabolic profile was obtained using proton NMR spectroscopy. NMR spectra were integrated into seven integration regions, which reflect relative metabolites.

RESULTS

A significant metabolic disorder symptom appeared in the overweight and obese group, and increased lipid deposition occurred in the abdomen, hepatocytes, and muscles that were statistically significant. Overall, the visceral fat depots had a marked influence on dyslipidemia biomarkers, blood triglyceride (r = 0.592, p < 0.001), and high-density lipoprotein cholesterol (r = -0.484, p < 0.001). Intrahepatocellular lipid was associated with diabetes predictors for hemoglobin (HbA1c%; r = 0.379, p < 0.001) and for fasting blood sugar (r = 0.333, p < 0.05). The lipid signals in serum triglyceride and glucose signals gave similar correspondence to biochemical lipid profiles.

CONCLUSIONS

This study proves the association between alteration in metabolome in young adults, which is the key population for early prevention of obesity and metabolic syndrome. This study suggests that dyslipidemia prevalence is influenced mainly by the visceral fat depot, and liver fat depot is a key determinant for glucose metabolism and hyperglycemia. Moreover, noninvasive advanced molecular imaging completely elucidated the impact of fat distribution on the anthropometric and laboratory parameters, especially indices of the metabolic syndrome biomarkers in young adults.

Superficial vs Deep Subcutaneous Adipose Tissue: Sex-Specific Associations With Hepatic Steatosis and Metabolic Traits

CONTEXT

Subcutaneous adipose tissue (SAT) is not homogeneous, as the fascia scarpa separates the deep SAT (dSAT) from the superficial SAT (sSAT).

OBJECTIVE

The aim of this study is to evaluate the sex-specific associations of sSAT and dSAT with hepatic steatosis and metabolic syndrome in overweight individuals.

METHODS

We recruited 285 individuals with a body mass index (BMI) greater than or equal to 27 and aged 55 to 81 years. Abdominal magnetic resonance imaging was performed around level L4 to L5 to measure visceral adipose tissue (VAT), dSAT, and sSAT volumes. The amount of hepatic fat was quantified by MR spectroscopy.

RESULTS

Men had significantly higher volumes of VAT (122.6 cm3 vs 98.7 cm3, P < .001) and had only half the volume of sSAT compared to women adjusted for BMI (50.3 cm3 in men vs 97.0 cm3 in women, P < .001). dSAT correlated significantly with hepatic fat content in univariate analysis (standardized β = .190, P < .05), while VAT correlated significantly with hepatic steatosis in a multivariate model, adjusted for age, alcohol use, and other abdominal fat compartments (standardized β = .184, P = .037). Moreover, dSAT in men correlated negatively with HDL cholesterol (standardized β = -0.165, P = .038) in multivariate analyses. In women with a BMI between 30 and 40, in a multivariate model adjusted for age, alcohol use, and other abdominal fat compartments, VAT correlated positively (standardized β = -.404, P = .003), and sSAT negatively (standardized β = -.300, P = .04) with hepatic fat content.

CONCLUSION

In men, dSAT is associated with hepatic steatosis and adverse metabolic traits, such as lower HDL cholesterol levels, whereas in women with obesity sSAT shows a beneficial relation with respect to hepatic fat content.

Development of Visceral and Subcutaneous-Abdominal Adipose Tissue in Breastfed Infants during First Year of Lactation

This study aimed to investigate relationships between infant abdominal visceral and subcutaneous adiposity and human milk (HM) components and maternal body composition (BC) during first year of lactation. Subcutaneous-abdominal depth (SAD), subcutaneous-abdominal fat area (SFA), visceral depth (VD) and preperitoneal fat area of 20 breastfed infants were assessed at 2, 5, 9 and 12 months using ultrasound. Maternal BC was determined with bioimpedance spectroscopy. HM macronutrients and bioactive components concentrations and infant 24-h milk intake were measured and calculated daily intakes (CDI) determined. Maternal adiposity associated with infant SFA (negatively at 2, 5, 12, positively at 9 months, all overall p < 0.05). 24-h milk intake positively associated with infant SAD (p = 0.007) and VD (p = 0.013). CDI of total protein (p = 0.013), total carbohydrates (p = 0.004) and lactose (p = 0.013) positively associated with SFA. Lactoferrin concentration associated with infant VD (negatively at 2, 12, positively at 5, 9 months, overall p = 0.003). CDI of HM components and maternal adiposity have differential effects on development of infant visceral and subcutaneous abdominal adiposity. Maintaining healthy maternal BC and continuing breastfeeding to 12 months and beyond may facilitate favourable BC development reducing risk of obesity.

The longitudinal association between early-life screen viewing and abdominal adiposity-findings from a multiethnic birth cohort study

IMPORTANCE

Screen viewing in adults has been associated with greater abdominal adiposity, with the magnitude of associations varying by sex and ethnicity, but the evidence is lacking at younger ages. We aimed to investigate sex- and ethnic-specific associations of screen-viewing time at ages 2 and 3 years with abdominal adiposity measured by magnetic resonance imaging at age 4.5 years.

METHODS

The Growing Up in Singapore Towards healthy Outcomes is an ongoing prospective mother-offspring cohort study. Parents/caregivers reported the time their child spent viewing television, handheld devices, and computer screens at ages 2 and 3 years. Superficial and deep subcutaneous and visceral abdominal adipose tissue volumes were quantified from magnetic resonance images acquired at age 4.5 years. Associations between screen-viewing time and abdominal adipose tissue volumes were examined by multivariable linear regression adjusting for confounding factors.

RESULTS

In the overall sample (n = 307), greater total screen-viewing time and handheld device times were associated with higher superficial and deep subcutaneous adipose tissue volumes, but not with visceral adipose tissue volumes. Interactions with child sex were found, with significant associations with superficial and deep subcutaneous and visceral adipose tissue volumes in boys, but not in girls. Among boys, the increases in mean (95% CI) superficial and deep subcutaneous and visceral adipose tissue volumes were 24.3 (9.9, 38.7), 17.6 (7.4, 27.8), and 7.8 (2.1, 13.6) mL per hour increase in daily total screen-viewing time, respectively. Ethnicity-specific analyses showed associations of total screen-viewing time with abdominal adiposity only in Malay children. Television viewing time was not associated with abdominal adiposity.

CONCLUSION

Greater total screen-viewing time (and in particular, handheld device viewing time) was associated with higher abdominal adiposity in boys and Malay children. Additional studies are necessary to confirm these associations and to examine screen-viewing interventions for preventing excessive abdominal adiposity and its adverse cardiometabolic consequences.

Epigenetic modifications underlie the differential adipogenic potential of preadipocytes derived from human subcutaneous fat tissue

AIM

Ceiling culture-derived preadipocytes (ccdPAs) and adipose-derived stem cells (ASCs) can be harvested from human subcutaneous fat tissue using the specific gravity method. Both cell types possess a similar spindle shape without lipid droplets. We previously reported that ccdPAs have a higher adipogenic potential than ASCs, even after a 7-week culture. We performed a genome-wide epigenetic analysis to examine the mechanisms contributing to the adipogenic potential differences between ccdPAs and ASCs.

MATERIALS AND METHODS

Methylation analysis of cytosines followed by guanine (CpG) using a 450K BeadChip was performed on human ccdPAs and ASCs isolated from three metabolically healthy females. Chromatin immunoprecipitation sequencing (ChIP-seq) was performed to evaluate trimethylation at lysine 4 of histone 3 (H3K4me3).

RESULTS

Unsupervised machine learning using t-distributed stochastic neighbor embedding (tSNE) to interpret 450,000-dimensional methylation assay data showed that the cells were divided into ASC and ccdPA groups. In KEGG pathway analysis of 1,543 genes with differential promoter CpG methylation, the peroxisome proliferator-activated receptor (PPAR) and adipocytokine signaling pathways ranked in the top 10 pathways. In the PPAR gamma gene, H3K4me3 peak levels were higher in ccdPAs than in ASCs, whereas promoter CpG methylation levels were significantly lower in ccdPAs than in ASCs. Similar differences in promoter CpG methylation were also seen in the fatty acid-binding protein 4 (FABP4) and leptin genes.

CONCLUSION

We analyzed the epigenetic status of adipogenesis-related genes as a potential mechanism underlying the differences in adipogenic differentiation capability between ASCs and ccdPAs.

Increasing changes in visceral adiposity is associated with higher risk for colorectal adenoma: Multilevel analysis in a prospective cohort

BACKGROUND AND AIM

While many studies demonstrated an association between visceral adiposity and colorectal adenoma (CRA), the effect of longitudinal changes in body fat composition on CRA is unclear. We investigated the longitudinal association between changes in visceral adiposity and CRA occurrence.

METHODS

Between 2006 and 2018, 732 (62.8%) of the 1165 subjects in a prospective cohort voluntarily underwent follow-up abdominal fat computed tomography and colonoscopy. We defined incident and recurrent CRA as adenoma detected at follow-up colonoscopy from negative and positive adenoma at baseline colonoscopy, respectively. Multilevel survival analysis examined the longitudinal association between changes in visceral fat and CRA.

RESULTS

During a median follow-up of 7.4 years, 400 (54.6%) subjects developed CRA. In multivariable analysis, increasing changes in visceral adipose tissue (VAT) area were associated with higher risk of incident adenoma (hazard ratio [HR] 1.21, 95% confidence interval [CI] 1.00-1.46 for change per 10 cm² increase; HR 1.79, 95% CI 1.08-2.97 for highest vs lowest quartile, P values for trend = 0.045). Likewise, increasing changes in VAT area were independently associated with a higher risk of recurrent adenoma (HR 1.35, 95% CI 1.13-1.62 for change per 10 cm² increase; HR 1.62, 95% CI 1.04-2.52 for highest vs lowest quartile, P values for trend = 0.001). Changes in subcutaneous adipose tissue area were not independently associated with CRA.

CONCLUSION

Increasing changes in VAT area were longitudinally associated with a higher risk of incident and recurrent CRA, independent of risk factors, suggesting that visceral adiposity may be an important target in CRA prevention.

Waist Circumference and BMI Are Strongly Correlated with MRI-Derived Fat Compartments in Young Adults

Young adulthood is increasingly considered as a vulnerable age group for significant weight gain, and it is apparent that there is an increasing number of new cases of metabolic syndrome developing among this population. This study included 60 young adult volunteers (18-26 years old). All participants obtained a calculated total abdominal fat percentage, subcutaneous fat percentage, and visceral fat percentage using a semiautomatic segmentation technique from T1-weighted magnetic resonance imaging (MRI) images of the abdomen. The results show strongest correlation between abdominal fat and BMI (r = 0.824) followed by subcutaneous fat (r = 0.768), and visceral fat (r = 0.633) respectively, (p < 0.001 for all, after having been adjusted for age and gender). Among anthropometric measurements, waist circumference showed strong correlation with all fat compartments (r = 0.737 for abdominal, r = 0.707 for subcutaneous fat, and r = 0.512 for visceral fat; p < 0.001 for all). The results obtained from examining the blood revealed that there was a moderate positive correlation relationship between all fat compartments with triglyceride, high-density lipoprotein, and fasting glucose levels (p < 0.05 for all). This study suggests that both BMI and waist circumference could be used to assess the fat compartments and treatment targets to reduce the risk of metabolic disorders and health risks in the young adult population.

Effect of Dietary Strategies on Respiratory Quotient and Its Association with Clinical Parameters and Organ Fat Loss: A Randomized Controlled Trial

The relation between changes in respiratory quotient (RQ) following dietary interventions and clinical parameters and body fat pools remains unknown. In this randomized controlled trial, participants with moderate abdominal obesity or/and dyslipidemia (n = 159) were randomly assigned to a Mediterranean/low carbohydrate (MED/LC, n = 80) or a low fat (LF, n = 79) isocaloric weight loss diet and completed a metabolic assessment. Changes in RQ (measured by indirect calorimeter), adipose-tissue pools (MRI), and clinical measurements were assessed at baseline and after 6 months of intervention. An elevated RQ at baseline was significantly associated with increased visceral adipose tissue, hepatic fat, higher levels of insulin and homeostatic insulin resistance. After 6 months, body weight had decreased similarly between the diet groups (−6 ± 6 kg). However, the MED/LC diet, which greatly improved metabolic health, decreased RQ significantly more than the LF diet (−0.022 ± 0.007 vs. −0.002 ± 0.008, p = 0.005). Total cholesterol and diastolic blood pressure were independently associated with RQ changes (p = 0.045). RQ was positively associated with increased superficial subcutaneous-adipose-tissue but decreased renal sinus, pancreatic, and intramuscular fats after adjusting for confounders. Fasting RQ may reflect differences in metabolic characteristics between subjects affecting their potential individual response to the diet.

Relationship of Visceral Adipose Tissue With Dilated Perivascular Spaces

BACKGROUND

Dilated perivascular spaces (dPVS) are considered to be a type of cerebral small vessel disease (CSVD) as well as an important part of the glymphatic system. Although obesity has been shown to play a significant role in the development of CSVD, there are no studies addressing the correlation between obesity and dPVS. We aimed to study the relationship between abdominal fat distribution and dPVS in neurologically healthy cohorts.

METHODS

A total of 989 subjects, who were examined during a health examination project, were included in this study. We measured both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) areas using abdominal computed tomography. The dPVS scores were also evaluated in the basal ganglia (BG) and the centrum semiovale (CSO).

RESULTS

In a multivariate ordinal regression analysis, the relationship between VAT area and CSO-dPVS scores remained significant (β [95% confidence interval {CI} = 0.00003395] [0.00001074-0.00005716], P = 0.004), especially in male cohorts (β [95% CI] = 0.00004325 [0.00001772-0.00006878], P = 0.001) after adjusting for age; sex; and glucose, creatinine, uric acid, high-density lipoprotein, and low-density lipoprotein levels, while no association was found between SAT area and dPVS scores. The effects of quartile VAT area on CSO-dPVS were also significant in male cohorts (odds ratio [95% CI] = 1.33 [1.139 - 1.557], P < 0.001).

CONCLUSION

We demonstrated a positive association between VAT and CSO-dPVS scores in a healthy cohort, which was more prominent in males.

Adipose-Derived Mesenchymal Stromal Cells in Regenerative Medicine: State of Play, Current Clinical Trials, and Future Prospects

Significance: Wound healing is a complex process involving pain and inflammation, where innervation plays a central role. Managing wound healing and pain remains an important issue, especially in pathologies such as excessive scarring (often leading to fibrosis) or deficient healing, leading to chronic wounds. Recent Advances: Advances in therapies using mesenchymal stromal cells offer new insights for treating indications that previously lacked options. Adipose-derived mesenchymal stromal cells (AD-MSCs) are now being used to a much greater extent in clinical trials for regenerative medicine. However, to be really valid, these randomized trials must imperatively follow strict guidelines such as consolidated standards of reporting trials (CONSORT) statement. Indeed, AD-MSCs, because of their paracrine activities and multipotency, have potential to cure degenerative and/or inflammatory diseases. Combined with their relatively easy access (from adipose tissue) and proliferation capacity, AD-MSCs represent an excellent candidate for allogeneic treatments. Critical Issues: The success of AD-MSC therapy may depend on the robustness of the biological functions of AD-MSCs, which requires controlling source heterogeneity and production processes, and development of biomarkers that predict desired responses. Several studies have investigated the effect of AD-MSCs on innervation, wound repair, or pain management separately, but systematic evaluation of how those effects could be combined is lacking. Future Directions: Future studies that explore how AD-MSC therapy can be used to treat difficult-to-heal wounds, underlining the need to thoroughly characterize the cells used, and standardization of preparation processes are needed. Finally, how this a priori easy-to-use cell therapy treatment fits into clinical management of pain, improvement of tissue healing, and patient quality of life, all need to be explored.

Secondary analyses of global datasets: do obesity and physical activity explain variation in diabetes risk across populations?

Type 2 diabetes rates vary significantly across geographic regions. These differences are sometimes assumed to be entirely driven by differential distribution of environmental triggers, including obesity and insufficient physical activity (IPA). In this review, we discuss data which conflicts with this supposition. We carried out a secondary analysis of publicly available data to unravel the relative contribution of obesity and IPA towards diabetes risk across different populations. We used sex-specific, age-standardized estimates from Non-Communicable Disease Risk Factor Collaboration (NCD-RisC) on diabetes (1980-2014) and obesity (1975-2016) rates, in 200 countries, and from WHO on IPA rates in 168 countries in the year 2016. NCD-RisC and WHO organized countries into nine super-regions. All analyses were region- and sex-specific. Although obesity has been increasing since 1975 in every part of the world, this was not reflected in a proportional increase in diabetes rates in several regions, including Central and Eastern Europe, and High-income western countries region. Similarly, the association of physical inactivity with diabetes is not homogeneous across regions. Countries from different regions across the world could have very similar rates of diabetes, despite falling on opposite ends of IPA rate spectrum. The combined effect of obesity and IPA on diabetes risk was analyzed at the worldwide and country level. The overall findings highlighted the larger impact of obesity on disease risk; low IPA rates do not seem to be protective of diabetes, when obesity rates are high. Despite that, some countries deviate from this overall observation. Sex differences were observed across all our analyses. Overall, data presented in this review indicate that different populations, while experiencing similar environmental shifts, are apparently differentially subject to diabetes risk. Sex-related differences observed suggest that males and females are either subject to different risk factor exposures or have different responses to them.

Association of Adipose Tissue Distribution With Type 2 Diabetes in Breast Cancer Patients

PURPOSE

We examined the association of adipose tissue distribution with type 2 diabetes (T2D) in breast cancer patients.

METHODS

Participants (N = 238) diagnosed with breast cancer at 20-75 years old who received breast cancer treatment at a major hospital from January 1, 2012, to December 31, 2017, with at least one completed and identifiable abdominal or pelvic computed tomography (CT) scan and data regarding race and ethnicity were included. Thirty-two breast cancer patients were identified as T2D patients after their breast cancer diagnoses. The adipose tissue distribution (visceral fat area [VFA], subcutaneous fat area [SFA], and the ratio of VFA to SFA [VFA/SFA]) was quantified on CT images of the third lumbar vertebra. T2D status was retrieved from patients' electronic medical records. The association of adipose tissue distribution with T2D in women with breast cancer was examined using multivariable logistic regression.

RESULTS

Participants with T2D had significantly smaller SFA compared to those without T2D (odds ratio [OR] = 0.88, 95% confidence interval [95% CI] = 0.81-0.96, per 10 cm2 SFA). A positive association of VFA/SFA ratio with T2D was observed (OR = 19.57, 95% CI = 3.26-117.42, per unit VFA/SFA), although the estimate was imprecise.

CONCLUSIONS

The amount of subcutaneous adipose tissue was inversely associated with T2D, and the ratio of the amount of visceral adipose tissue to the amount of subcutaneous adipose tissue was positively associated with T2D in breast cancer patients.

Wine and Health-New Evidence

Health benefits of moderate wine consumption have been studied during the past decades, first in observational studies and more recently, in experimental settings and randomized controlled studies. Suggested biological pathways include antioxidant, lipid regulating, and anti-inflammatory effects. Both the alcoholic and polyphenolic components of wine are believed to contribute to these beneficial effects. Although several of these studies demonstrated protective associations between moderate drinking and cardiovascular disease, atherosclerosis, hypertension, certain types of cancer, type 2 diabetes, neurological disorders, and the metabolic syndrome, no conclusive recommendations exist regarding moderate wine consumption. Yet, it is suggested that the physician and patient should discuss alcohol use. In the CASCADE (CArdiovaSCulAr Diabetes & Ethanol) trial, 224 abstainers with type 2 diabetes were randomized to consume red wine, white wine or mineral water for two years. Here, we summarize our previous findings, offer new evidence concerning the differential effects of wine consumption among men and women, and further suggest that initiating moderate alcohol consumption among well-controlled persons with type 2 diabetes is apparently safe, in regard to changes in heart rate variability and carotid plaque formation.

NAFLD and cardiovascular diseases: a clinical review

Non-alcoholic fatty liver DISEASE (NAFLD) is the most common chronic liver disease in Western countries and affects approximately 25% of the adult population. Since NAFLD is frequently associated with further metabolic comorbidities such as obesity, type 2 diabetes mellitus, or dyslipidemia, it is generally considered as the hepatic manifestation of the metabolic syndrome. In addition to its potential to cause liver-related morbidity and mortality, NAFLD is also associated with subclinical and clinical cardiovascular disease (CVD). Growing evidence indicates that patients with NAFLD are at substantial risk for the development of hypertension, coronary heart disease, cardiomyopathy, and cardiac arrhythmias, which clinically result in increased cardiovascular morbidity and mortality. The natural history of NAFLD is variable and the vast majority of patients will not progress from simple steatosis to fibrosis and end stage liver disease. However, patients with progressive forms of NAFLD, including non-alcoholic steatohepatitis (NASH) and/or advanced fibrosis, as well as NAFLD patients with concomitant types 2 diabetes are at highest risk for CVD. This review describes the underlying pathophysiological mechanisms linking NAFLD and CVD, discusses the role of NAFLD as a metabolic dysfunction associated cardiovascular risk factor, and focuses on common cardiovascular manifestations in NAFLD patients.

Maternal glycemia during pregnancy and offspring abdominal adiposity measured by MRI in the neonatal period and preschool years: The Growing Up in Singapore Towards healthy Outcomes (GUSTO) prospective mother-offspring birth cohort study

BACKGROUND

Gestational diabetes is associated with unfavorable body fat distribution in offspring. However, less is known about the effects across the range of maternal gestational glycemia on offspring abdominal adiposity (AA) in infancy and early childhood.

OBJECTIVES

This study determined the association between gestational glycemia and offspring AA measured by MRI in the neonatal period and during the preschool years.

METHODS

Participants were mother-offspring pairs from the GUSTO (Growing Up in Singapore Towards healthy Outcomes) prospective cohort study. Children who underwent MRI within 2 wk postdelivery (n = 305) and/or at preschool age, 4.5 y (n = 273), and whose mothers had a 2-h 75-g oral-glucose-tolerance test (OGTT) at 26-28 weeks of gestation were included. AA measured by adipose tissue compartment volumes-abdominal superficial (sSAT), deep subcutaneous (dSAT), and internal (IAT) adipose tissue-was quantified from MRI images.

RESULTS

Adjusting for potential confounders including maternal prepregnancy BMI, each 1-mmol/L increase in maternal fasting glucose was associated with higher SD scores for sSAT (0.66; 95% CI: 0.45, 0.86), dSAT (0.65; 95% CI: 0.44, 0.87), and IAT (0.64; 95% CI: 0.42, 0.86) in neonates. Similarly, each 1-mmol/L increase in 2-h OGTT glucose was associated with higher neonatal sSAT (0.11; 95% CI: 0.03, 0.19) and dSAT (0.09; 95% CI: 0.00, 0.17). These associations were stronger in female neonates but only persisted in girls between fasting glucose, and sSAT and dSAT at 4.5 y.

CONCLUSIONS

A positive association between maternal glycemia and neonatal AA was observed across the whole range of maternal mid-gestation glucose concentrations. These findings may lend further support to efforts toward optimizing maternal hyperglycemia during pregnancy. The study also provides suggestive evidence on sex differences in the impact of maternal glycemia, which merits further confirmation in other studies.This trial was registered at clinicaltrials.gov as NCT01174875.

Association between abdominal fat distribution and coronary plaque instability in patients with acute coronary syndrome

BACKGROUND AND AIMS

This study aimed to assess possible association of detailed abdominal fat profiles with coronary plaque characteristics in patients with acute coronary syndrome (ACS).

METHODS AND RESULTS

In 60 patients with ACS, culprit arteries were evaluated at 1-mm intervals (length analyzed: 66 ± 28 mm) by grayscale and integrated backscatter intravascular ultrasound (IB-IVUS) before percutaneous coronary intervention. Standard IVUS indexes (as a volume index: volume/length), plaque components (as percent tissue volume) and fibrous cap thickness (FCT) were assessed by IB-IVUS. Plain abdominal computed tomography was performed to evaluate subcutaneous adipose tissue (SAT) area, visceral adipose tissue (VAT) area, and VAT/SAT ratio. While SAT area only correlated with vessel volume (r = 0.27, p = 0.04), VAT area correlated positively with vessel (r = 0.30, p = 0.02) and plaque (r = 0.33, p = 0.01) volumes and negatively with FCT (r = -0.26, p = 0.049), but not with percent plaque volume and plaque tissue components. In contrast, higher VAT/SAT ratio significantly correlated with higher percent lipid (r = 0.34, p = 0.008) and lower percent fibrous (r = -0.34, p = 0.007) volumes with a trend toward larger percent plaque volume (r = 0.19, p = 0.15), as well as thinner FCT (r = -0.53, p < 0.0001). In the multiple regression analysis, higher VAT/SAT ratio was independently associated with higher percent lipid with lower percent fibrous volumes (p = 0.03 for both) and thinner fibrous cap thickness (p = 0.0001).

CONCLUSION

Coronary plaque vulnerability, defined as increased lipid content with thinner fibrous cap thickness, appears to be more related to abnormal abdominal fat distribution, or so-called hidden obesity, compared with visceral or subcutaneous fat amount alone in patients with ACS.

Sex-Specific Regulation of Inflammation and Metabolic Syndrome in Obesity

Supplemental Digital Content is available in the text.

Objective:

Metabolic dysregulation and inflammation are important consequences of obesity and impact susceptibility to cardiovascular disease. Anti-inflammatory therapy in cardiovascular disease is being developed under the assumption that inflammatory pathways are identical in women and men, but it is not known if this is indeed the case. In this study, we assessed the sex-specific relation between inflammation and metabolic dysregulation in obesity.

Approach and Results:

Three hundred two individuals were included, half with a BMI 27 to 30 kg/m² and half with a BMI>30 kg/m², 45% were women. The presence of metabolic syndrome was assessed according to the National Cholesterol Education Program-ATPIII criteria, and inflammation was studied using circulating markers of inflammation, cell counts, and ex vivo cytokine production capacity of isolated immune cells. Additionally, lipidomic and metabolomic data were gathered, and subcutaneous fat biopsies were histologically assessed.

Metabolic syndrome is associated with an increased inflammatory profile that profoundly differs between women and men: women with metabolic syndrome show a lower concentration of the anti-inflammatory adiponectin, whereas men show increased levels of several pro-inflammatory markers such as IL (interleukin)-6 and leptin. Adipose tissue inflammation showed similar sex-specific associations with these markers. Peripheral blood mononuclear cells isolated from men, but not women, with metabolic syndrome display enhanced cytokine production capacity.

Conclusions:

We identified sex-specific pathways that influence inflammation in obesity. Excessive production of proinflammatory cytokines was observed in men with metabolic syndrome. In contrast, women typically showed reduced levels of the anti-inflammatory adipokine adiponectin. These different mechanisms of inflammatory dysregulation between women and men with obesity argue for sex-specific therapeutic strategies.

Expansion and Impaired Mitochondrial Efficiency of Deep Subcutaneous Adipose Tissue in Recent-Onset Type 2 Diabetes

CONTEXT/OBJECTIVE

Impaired adipose tissue (AT) function might induce recent-onset type 2 diabetes (T2D). Understanding AT energy metabolism could yield novel targets for the treatment of T2D.

DESIGN/PATIENTS

Male patients with recently-diagnosed T2D and healthy male controls (CON) of similar abdominal subcutaneous AT (SAT)-thickness, fat mass, and age (n = 14 each), underwent hyperinsulinemic-euglycemic clamps with [6,6-2H2]glucose and indirect calorimetry. We assessed mitochondrial efficiency (coupling: state 3/4o; proton leak: state 4o/u) via high-resolution respirometry in superficial (SSAT) and deep (DSAT) SAT-biopsies, hepatocellular lipids (HCL) and fat mass by proton-magnetic-resonance-spectroscopy and -imaging.

RESULTS

T2D patients (known diabetes duration: 2.5 [0.1; 5.0] years) had 43%, 44%, and 63% lower muscle insulin sensitivity (IS), metabolic flexibility (P < 0.01) and AT IS (P < 0.05), 73% and 31% higher HCL (P < 0.05), and DSAT-thickness (P < 0.001), but similar hepatic IS compared with CON. Mitochondrial efficiency was ~22% lower in SSAT and DSAT of T2D patients (P < 0.001) and ~8% lower in SSAT vs DSAT (P < 0.05). In both fat depots, mitochondrial coupling correlated positively with muscle IS and metabolic flexibility (r ≥ 0.40; P < 0.05), proton leak correlated positively (r ≥ 0.51; P < 0.01) and oxidative capacity negatively (r ≤ -0.47; P < 0.05) with fasting free fatty acids (FFA). Metabolic flexibility correlated positively with SAT-oxidative capacity (r ≥ 0.48; P < 0.05) and negatively with DSAT-thickness (r = -0.48; P < 0.05). DSAT-thickness correlated negatively with mitochondrial coupling in both depots (r ≤ -0.50; P < 0.01) and muscle IS (r = -0.59; P < 0.01), positively with FFA during clamp (r = 0.63; P < 0.001) and HCL (r = 0.49; P < 0.01).

CONCLUSIONS

Impaired mitochondrial function, insulin resistance, and DSAT expansion are AT abnormalities in recent-onset T2D that might promote whole-body insulin resistance and increased substrate flux to the liver.

Impact of adiposity on staging and prognosis of colorectal cancer

Abdominal visceral fat is a well-recognized a risk for colorectal cancer (CRC). In contrast to the risk for CRC, the impact of adiposity in disease staging and patient survival is less well-established. Our aim was to critically review the literature on the influence of adiposity assessed by different methods routinely used in clinical settings, on CRC staging and prognosis. In the 32 studies reviewed, overweight was initially identified as a survival advantage, an evidence that was later challenged by studies suggesting that body adiposity is likely to have a deleterious effect in CRC outcomes, particularly in males. Hence, whether obesity has a negative impact in CRC staging or prognosis remains controversial. In sum, addressing the impact of body fat in CRC biological behavior is still an unmet need. Understanding how adiposity influences CRC staging and prognosis could allow further patient risk stratification for devising targeted interventions and improve clinical outcomes.

Quantitative analyses of adiposity dynamics in zebrafish

Adipose tissues often exhibit subtle, quantitative differences between individuals, leading to a graded series of adiposity phenotypes at the population level. Robust, quantitative analyses are vital for studying these differences. In this Commentary we highlight two articles from our lab that employ sensitive new methods in zebrafish capable of delineating complex and quantitative adiposity phenotypes. In the first article, we utilized in vivo imaging to systematically quantify zebrafish adipose tissues. We identified 34 regionally distinct zebrafish adipose tissues and developed statistical models to predict the size and variance of each adipose tissue over the course of zebrafish growth. We then employed these models to identify effects of strain and diet on adipose tissue growth. In the second article, we employed deep phenotyping to study complex disease-related adiposity traits. Using this methodology, we identified that adipose tissues have unique capacities to re-deposit lipid following food restriction and re-feeding. These distinct re-deposition potentials led to widespread fat distribution changes following re-feeding. We discuss how these novel findings may provide relevance to health conditions such as anorexia nervosa. Together, the strategies described in these two articles can be used as unbiased and quantitative methods to uncover new relationships between genotype, diet and adiposity.

Ethnic differences in hepatic, pancreatic, muscular and visceral fat deposition in healthy men of white European and black west African ethnicity

AIMS

We aimed to assess ethnic differences in visceral adipose tissue (VAT), intrahepatic (IHL), intrapancreatic (IPL) and intramyocellular lipids (IMCL) between healthy white European (WE) and black west African (BWA) men.

METHODS

23 WE and 20 BWA men underwent Dixon-magnetic resonance imaging to quantify VAT, IHL and IPL; and proton-magnetic resonance spectroscopy to quantify IMCL. Insulin sensitivity and beta-cell function were determined using homeostasis model assessment (HOMA-2).

RESULTS

BWA men exhibited significantly lower VAT (P = 0.021) and IHL (P = 0.044) than WE men, but comparable IPL (P = 0.92) and IMCL (P = 0.87). VAT was associated with IPL in both ethnicities (WE: P < 0.001; BWA: P = 0.001) but the relationship with IHL differed by ethnicity (P_interaction = 0.018) and was only significant in WE men (WE: P < 0.001; BWA: P = 0.36). All ectopic fat depots inversely associated with insulin sensitivity and positively associated with beta-cell function in WE but not BWA men.

CONCLUSIONS

Lower VAT and IHL, and their lack of interrelation, in BWA men suggests ethnic differences exist in the mechanisms of ectopic fat deposition. The lack of association between ectopic fat with insulin sensitivity and beta-cell function in BWA men may indicate a lesser role for ectopic fat in the development of type 2 diabetes mellitus in black populations.

The beneficial effects of Mediterranean diet over low-fat diet may be mediated by decreasing hepatic fat content

BACKGROUND & AIM

It is unclear if a reduction in hepatic fat content (HFC) is a major mediator of the cardiometabolic benefit of lifestyle intervention, and whether it has prognostic significance beyond the loss of visceral adipose tissue (VAT). In the present sub-study, we hypothesized that HFC loss in response to dietary interventions induces specific beneficial effects independently of VAT changes.

METHODS

In an 18-month weight-loss trial, 278 participants with abdominal obesity/dyslipidemia were randomized to low-fat (LF) or Mediterranean/low-carbohydrate (MED/LC + 28 g walnuts/day) diets with/without moderate physical activity. HFC and abdominal fat-depots were measured using magnetic resonance imaging at baseline, after 6 (sub-study, n = 158) and 18 months.

RESULTS

Of 278 participants (mean HFC 10.2% [range: 0.01%-50.4%]), the retention rate was 86.3%. The %HFC substantially decreased after 6 months (-6.6% absolute units [-41% relatively]) and 18 months (-4.0% absolute units [-29% relatively]; p <0.001 vs. baseline). Reductions of HFC were associated with decreases in VAT beyond weight loss. After controlling for VAT loss, decreased %HFC remained independently associated with reductions in serum gamma glutamyltransferase and alanine aminotransferase, circulating chemerin, and glycated hemoglobin (p <0.05). While the reduction in HFC was similar between physical activity groups, MED/LC induced a greater %HFC decrease (p = 0.036) and greater improvements in cardiometabolic risk parameters (p <0.05) than the LF diet, even after controlling for VAT changes. Yet, the greater improvements in cardiometabolic risk parameters induced by MED/LC were all markedly attenuated when controlling for HFC changes.

CONCLUSIONS

%HFC is substantially reduced by diet-induced moderate weight loss and is more effectively reduced by the MED/LC diet than the LF diet, independently of VAT changes. The beneficial effects of the MED/LC diet on specific cardiometabolic parameters appear to be mediated more by decreases in %HFC than VAT loss.

LAY SUMMARY

High hepatic fat content is associated with metabolic syndrome, type 2 diabetes mellitus, and coronary heart disease. In the CENTRAL 18-month intervention trial, a Mediterranean/low-carbohydrate diet induced a greater decrease in hepatic fat content than a low-fat diet, conferring beneficial health effects that were beyond the favorable effects of visceral fat loss. ClinicalTrials.gov Identifier: NCT01530724.

Abdominal fatness and cerebral white matter hyperintensity

Although obesity has been proven as a risk factor of metabolic and cardiovascular diseases, there have been few studies addressing the association between obesity and cerebral white matter hyperintensity (WMH) volume with controversial findings. In this study, we evaluated the relationship between abdominal fat distribution and WMH volume in a neurologically healthy population. We performed an observational study in a consecutive series of subjects who were examined during voluntary health check-ups between January 2006 and December 2013. We directly measured both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) using abdominal computed tomography. The WMH volumes were also recorded quantitatively. A total of 2504 subjects were included in this study. In multivariate analysis, the relationship between SAT and WMH volume remained significant (β = -0.170, standard error [SE] = 0.065, P = .006) after adjusting for confounding factors. The protective effects of SAT on the WMH volume were more prominent in female participants (β = -0.295, SE = 0.138, P = .033) and in severely obese participants (β = -0.358, SE = 0.167, P = .033). Conclusively, we demonstrated a negative association between SAT and WMH volume in a healthy population.

High triglyceride/HDL cholesterol ratio is associated with silent brain infarcts in a healthy population

Background

Triglycerides (TG)/high-density lipoprotein (HDL) cholesterol ratio is a marker of small/dense low-density lipoprotein particles, which are closely associated with various metabolic and vascular diseases. However, the role of TG/HDL cholesterol ratio in cerebrovascular diseases has not been well studied. In this study, we evaluated the relationship between TG/HDL cholesterol ratio and the presence of silent brain infarct (SBI) in a neurologically healthy population.

Methods

We retrospectively evaluated consecutive participants in health check-ups between January 2006 and December 2013. SBI was defined as an asymptomatic, well-defined lesion with a diameter of ≥3 mm on T1- or T2-weighted images. TG/HDL cholesterol ratio was calculated after dividing absolute TG levels by absolute HDL cholesterol levels.

Results

Of 3172 healthy participants, 263 (8.3%) had SBI lesions. In multivariate analysis, TG/HDL cholesterol ratio was independently associated with SBI (adjusted odds ratio [aOR] = 1.16, 95% confidence interval [CI] = 1.00 to 1.34, P = 0.047). This association was prominent in males (aOR = 1.23, 95% CI = 1.03 to 1.48, P = 0.021), but not in females. In the analyses of the relationships between lipid parameters and SBI lesion burden, TG/HDL cholesterol ratio was positively correlated, and total cholesterol/TG ratio was negatively correlated with SBI lesion burden, in dose-response manners (P for trend = 0.015 and 0.002, respectively).

Conclusions

The TG/HDL cholesterol ratio was positively associated with the prevalence of SBI in a neurologically healthy population.

Electronic supplementary material

The online version of this article (10.1186/s12883-019-1373-8) contains supplementary material, which is available to authorized users.

Visceral and subcutaneous adipose tissue association with metabolic syndrome and its components in a South African population

BACKGROUND AND AIMS

A number of studies concur that visceral abdominal tissue (VAT) is a metabolic organ that mostly contributes to the metabolic consequences of obesity, however reports regarding subcutaneous adipose tissue (SAT) are controversial. We aimed to investigate the association between computed tomography measured visceral and subcutaneous adipose tissue and metabolic syndrome as well as its individual components.

METHODS

Computed tomography at level L4/L5 intervertebral disc space was performed in 401 mixed ancestry individuals from the Bellville South community of Cape Town. Data collections included OGTT, anthropometric, blood pressure, lipids, insulin cotinine, and alcohol consumption history.

RESULTS

Both VAT and SAT were increased in subjects with metabolic syndrome (p < 0.0001). In logistic regression, adjusted for age, gender, BMI, smoking, alcohol use, hypertension, diabetes and dyslipidaemia treatment (for women also adjusted for menopausal age) increasing quartiles of VAT were associated with metabolic syndrome {odds ratio (95% confidence interval) ≥ 4.14 (1.92-8.93), p < 0.001} and any type of hyperglycaemia (≥4.45 (1.89-10.47), p ≤ 0.001) whilst decreasing quartiles of SAT were associated with metabolic syndrome, p ≤ 0.037. In gender specific multivariate linear regression models, increased SAT levels were associated with 2-h plasma glucose, insulin levels and triglycerides in men, β ≥ 0.999, p ≤ 0.01.

CONCLUSIONS

Our study shows that increased VAT and decreased SAT are associated with metabolic syndrome in women, but in men increased SAT has deleterious effects to metabolic syndrome components. Therefore, in men increased SAT may like VAT increase the risk of diabetes development.

Association Between Early Life Weight Gain and Abdominal Fat Partitioning at 4.5 Years is Sex, Ethnicity, and Age Dependent

OBJECTIVE

The aim of this study was to investigate the independent associations between age-specific annual weight gain from birth to age 4 years and fat deposition in metabolically distinct compartments at age 4.5 years in a South Asian longitudinal birth cohort.

METHODS

Volumetric abdominal magnetic resonance imaging with comprehensive segmentation of deep and superficial subcutaneous adipose tissue (SAT) and visceral adipose tissues (VAT) was performed in 316 children (150 boys and 166 girls in three ethnic groups; 158 Chinese, 94 Malay, and 64 Indian) aged 4.5 years. Associations between fat volumes and annual relative weight gain conditional on past growth were assessed overall and stratified by sex and ethnicity.

RESULTS

Conditional relative weight gain had stronger associations with greater SAT and VAT at age 4.5 years in girls than boys and in Indians compared with Malay and Chinese. Overall, the magnitude of association was the largest during 2 to 3 years for SAT and 1 to 2 years for VAT. Despite similar body weight, Indian children and girls had the highest deep and superficial SAT volumes at age 4.5 years (all interactions P < 0.05). No significant sex or ethnic differences were observed in VAT. With increasing BMI, Indian children had the highest tendency to accumulate VAT, and girls accumulated more fat than boys in all depots (all interactions P < 0.001).

CONCLUSIONS

Indian ethnicity and female sex predisposed children to accumulate more fat in the VAT depot with increasing conditional relative weight gain in the second year of life. Thus, 1 to 2 years of age may be a critical window for interventions to reduce visceral fat accumulation.

Changes in Obesity Phenotype Distribution in Mixed-ancestry South Africans in Cape Town Between 2008/09 and 2014/16

Background: The concept of obesity phenotypes encompasses a different approach to evaluating the relationship between obesity and cardiometabolic diseases. Considering the minimal research on obesity phenotypes in Africa, we investigated these changes from 2008/09 to 2014/16 in the mixed ancestry population in Cape Town, South Africa. Methods: In all, 928 (2008/09) and 1969 (2014/16) ≥20 year old participants were included in two community-based cross-sectional studies. For obesity phenotype classification, a combination of body mass index (BMI) categories and prevalent cardiometabolic disease risk factors were used, with the presence of ≥2 cardiometabolic abnormalities defining abnormal metabolic status. Interaction tests were used to investigate changes in their distribution across the years of study. Results: Distribution of BMI categories differed significantly between the 2 years; normal weight, overweight and obese: 27.4, 27.4, and 45.3% in 2008/09 vs. 34.2, 23.6, and 42.2% in 2014/16 (p = 0.001). There was no differential effect in the distribution of obesity phenotypes pattern across the two time-points (interaction p = 0.126). Across BMI categories, levels of cardiometabolic risk factors linearly deteriorated in both metabolically healthy and abnormal participants (all p ≤ 0.018 for linear trends). Findings were not sensitive to the number of metabolic abnormalities included in the definition of obesity phenotypes. Conclusions: Our study showed negligible differences in obesity phenotypes over time, but a high burden of metabolic abnormalities among normal weight participants, and a significant proportion of metabolically health obese individuals. Further investigation is needed to improve risk stratification and cost-effective identification of individuals at high risk for cardiometabolic diseases.

Energy metabolism of white adipose tissue and insulin resistance in humans

BACKGROUND

Insulin resistance not only occurs in obesity, but also in lipodystrophy. Although adipose tissue mass affects metabolic fluxes and participates in interorgan crosstalk, the role of energy metabolism within white adipose tissue for insulin resistance is less clear.

MATERIALS AND METHODS

A Medline search identified in vivo studies in humans on energy and lipid metabolism in subcutaneous (SAT) and visceral adipose tissue (VAT). Studies in adipocyte cultures and transgenic animal models were included for the better understanding of the link between abnormal energy metabolism in adipose tissue and insulin resistance.

RESULTS

The current literature indicates that higher lipolysis and lower lipogenesis in VAT compared to SAT enhance portal delivery of lipid metabolites (glycerol and fatty acids) to the liver. Thus, the lower lipolysis and higher lipogenesis in SAT favour storage of excess lipids and allow for protection of insulin-sensitive tissues from lipotoxic effects. In insulin-resistant humans, enhanced lipolysis and impaired lipogenesis in adipose tissue lead to release of cytokines and lipid metabolites, ultimately promoting insulin resistance. Adipose tissue of insulin-resistant humans also displays lower expression of proteins involved in mitochondrial function. In turn, this leads to lower availability of mitochondria-derived energy sources for lipogenesis in adipose tissue.

CONCLUSIONS

Abnormal mitochondrial function in human white adipose tissue likely contributes to the secretion of lipid metabolites and lactate, which are linked to insulin resistance in peripheral tissues. However, the relevance of adipose tissue energy metabolism for the regulation of human insulin sensitivity remains to be further elucidated.

Relevance of human fat distribution on lipid and lipoprotein metabolism and cardiovascular disease risk

PURPOSE OF REVIEW

Upper body abdominal and lower body gluteofemoral fat depot masses display opposing associations with plasma lipid and lipoprotein and cardiovascular disease (CVD) risk profiles. We review developments on adipose tissue fatty acid metabolism in the context of body fat distribution and how that might be related to adverse lipid and lipoprotein profiles and CVD risk.

RECENT FINDINGS

Recent data have confirmed the paradoxical relationship of upper abdominal and lower body gluteofemoral adiposity and CVD risk. Mechanistically, this is likely to reflect the different ways fat depots handle lipid storage and release, which impacts directly and indirectly on lipid and lipoprotein metabolism. The upper body enhances immediate fat storage pathway with rapid uptake of dietary-derived fatty acids, whereas the lower body fat depot has a reduced lipid turnover accommodating a slower fat redistribution. Body fat distribution and the fat depots' ability to undergo appropriate expansion when fat storage is required, rather than overall body fatness, appear as the important determinant of metabolic health.

SUMMARY

A focus on fat distribution in overweight people, preferably using precise imaging methods, rather than quantifying total body fatness, is likely to provide the medical community with better tools to stratify and treat patients with obesity-related complications.

Obesity associated disease risk: the role of inherent differences and location of adipose depots

Obesity and associated metabolic co-morbidities are a worldwide public health problem. Negative health outcomes associated with obesity, however, do not arise from excessive adiposity alone. Rather, deleterious outcomes of adipose tissue accumulation are a result of how adipocytes are distributed to individual regions in the body. Due to our increased understanding of the dynamic relationship that exists between specific adipose depots and disease risk, an accurate characterization of total body adiposity as well as location is required to properly evaluate a population's disease risk. Specifically, distinctive tissue depots within the body include the lower body, upper body and abdominal (deep and superficial) subcutaneous regions, as well as visceral (mesenteric and omental) regions. Upper body and visceral adipose tissues are highly associated with metabolic dysfunction and chronic disease development, whereas lower body gluteofemoral subcutaneous adipose tissue imparts protection against diet-induced metabolic derangement. Each adipose depot functions distinctly as an endocrine organ hence it has a different level of impact on health outcomes. Effluent from adipose tissue can modulate the functions of other tissues, whilst receiving differential communication from the rest of the body via central nervous system innervation, metabolites and other signaling molecules. More so, adipose depots contain a diverse reservoir of tissue-resident immune cells that play an integral part in both maintaining tissue homeostasis, as well as propagating metabolically-induced inflammation. Overall, the conceptualization of obesity and associated risks needs updating to reflect the complexities of obesity. We review adipose tissue characteristics that are linked to deleterious or beneficial adipose tissue distributions.