Influence of glucagon-like peptide-1 receptor agonists on fat accumulation in patients with diabetes mellitus and non-alcoholic fatty liver disease or obesity: A systematic review and meta-analysis of randomized control trials

AIM

This systematic review and meta-analysis aimed to comprehensively evaluate the impact of glucagon-like peptide 1 receptor agonists (GLP-1RAs) on visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in individuals with diabetes mellitus and non-alcoholic fatty liver disease (NAFLD) or obesity.

METHODS

A search of PubMed, Embase, and Web of Science until October 2023 identified 13 Randomized Controlled Trials (RCTs) meeting the inclusion criteria. Bias risk was assessed using the Cochrane risk-of-bias instrument. Statistical analysis utilized standard mean differences (SMD) in Review Manager 5.4. Heterogeneity and publication bias were assessed. This study used the protocol registered with the Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY2023110020).

RESULTS

GLP-1RA treatment significantly reduced VAT (SMD -0.55, 95 % CI [-0.90, -0.19]), SAT (SMD -0.59, 95 % CI [-0.99, -0.19]), body weight (SMD -1.07, 95 % CI [-1.67, -0.47]), and body mass index (BMI) (SMD -1.10, 95 % CI [-1.74, -0.47]) compared to controls. Heterogeneity was observed for VAT (I2 = 79 %, P < 0.01), SAT (I2 = 73 %, P < 0.01), body weight (I2 = 82 %, P < 0.01), and BMI (I2 = 82 %, P < 0.01). No publication bias was detected for VAT (P = 0.57) and SAT (P = 0.18). GLP-1RA treatment improved fasting blood glucose (FBG), postprandial glucose (PPG), hemoglobin A1c (HbA1c), Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), and fibrosis-4 (FIB-4).

CONCLUSIONS

This meta-analysis highlights GLP-1RAs' potential to reduce fat accumulation, body weight, and BMI and improve glycemic control in individuals with diabetes mellitus and NAFLD or obesity. These findings supported using GLP-1RAs as promising therapeutic agents to address abnormal adipose tissue distribution and metabolic dysfunction.

Sarcopenia and adipose tissue evaluation by artificial intelligence predicts the overall survival after TAVI

Sarcopenia is a serious systemic disease that reduces overall survival. TAVI is selectively performed in patients with severe aortic stenosis who are not indicated for open cardiac surgery due to severe polymorbidity. Artificial intelligence-assisted body composition assessment from available CT scans appears to be a simple tool to stratify these patients into low and high risk based on future estimates of all-cause mortality. Within our study, the segmentation of preprocedural CT scans at the level of the lumbar third vertebra in patients undergoing TAVI was performed using a neural network (AutoMATiCA). The obtained parameters (area and density of skeletal muscles and intramuscular, visceral, and subcutaneous adipose tissue) were analyzed using Cox univariate and multivariable models for continuous and categorical variables to assess the relation of selected variables with all-cause mortality. 866 patients were included (median(interquartile range)): age 79.7 (74.9-83.3) years; BMI 28.9 (25.9-32.6) kg/m2. Survival analysis was performed on all automatically obtained parameters of muscle and fat density and area. Skeletal muscle index (SMI in cm2/m2), visceral (VAT in HU) and subcutaneous adipose tissue (SAT in HU) density predicted the all-cause mortality in patients after TAVI expressed as hazard ratio (HR) with 95% confidence interval (CI): SMI HR 0.986, 95% CI (0.975-0.996); VAT 1.015 (1.002-1.028) and SAT 1.014 (1.004-1.023), all p < 0.05. Automatic body composition assessment can estimate higher all-cause mortality risk in patients after TAVI, which may be useful in preoperative clinical reasoning and stratification of patients.

Reconstructed Human Skin with Hypodermis Shows Essential Role of Adipose Tissue in Skin Metabolism

BACKGROUND

Dysregulation of skin metabolism is associated with a plethora of diseases such as psoriasis and dermatitis. Until now, reconstructed human skin (RhS) models lack the metabolic potential of native human skin, thereby limiting their relevance to study human healthy and diseased skin. We aimed to determine whether incorporation of an adipocyte-containing hypodermis into RhS improves its metabolic potential and to identify major metabolic pathways up-regulated in adipose-RhS.

METHODS

Primary human keratinocytes, fibroblasts and differentiated adipose-derived stromal cells were co-cultured in a collagen/fibrin scaffold to create an adipose-RhS. The model was extensively characterized structurally in two- and three-dimensions, by cytokine secretion and RNA-sequencing for metabolic enzyme expression.

RESULTS

Adipose-RhS showed increased secretion of adipokines. Both RhS and adipose-RhS expressed 29 of 35 metabolic genes expressed in ex vivo native human skin. Addition of the adipose layer resulted in up-regulation of 286 genes in the dermal-adipose fraction of which 7 were involved in phase I (CYP19A1, CYP4F22, CYP3A5, ALDH3B2, EPHX3) and phase II (SULT2B1, GPX3) metabolism. Vitamin A, D and carotenoid metabolic pathways were enriched. Additionally, pro-inflammatory (IL-1β, IL-18, IL-23, IL-33, IFN-α2, TNF-α) and anti-inflammatory cytokine (IL-10, IL-12p70) secretion was reduced in adipose-RhS.

CONCLUSIONS

Adipose-RhS mimics healthy native human skin more closely than traditional RhS since it has a less inflamed phenotype and a higher metabolic activity, indicating the contribution of adipocytes to tissue homeostasis. Therefore it is better suited to study onset of skin diseases and the effect of xenobiotics.

Mycobacterium leprae is able to infect adipocytes, inducing lipolysis and modulating the immune response

Leprosy is a chronic infectious disease caused by the intracellular bacillus Mycobacterium leprae (M. leprae), which is known to infect skin macrophages and Schwann cells. Although adipose tissue is a recognized site of Mycobacterium tuberculosis infection, its role in the histopathology of leprosy was, until now, unknown. We analyzed the M. leprae capacity to infect and persist inside adipocytes, characterizing the induction of a lipolytic phenotype in adipocytes, as well as the effect of these infected cells on macrophage recruitment. We evaluated 3T3-L1-derived adipocytes, inguinal adipose tissue of SWR/J mice, and subcutaneous adipose tissue biopsies of leprosy patients. M. leprae was able to infect 3T3-L1-derived adipocytes in vitro, presenting a strong lipolytic profile after infection, followed by significant cholesterol efflux. This lipolytic phenotype was replicated in vivo by M. leprae injection into mice inguinal adipose tissue. Furthermore, M. leprae was detected inside crown-like structures in the subcutaneous adipose tissue of multibacillary patients. These data indicate that subcutaneous adipose tissue could be an important site of infection, and probably persistence, for M. leprae, being involved in the modulation of the innate immune control in leprosy via the release of cholesterol, MCP-1, and adiponectin.

Elevated 18F-FDG uptake in subcutaneous adipose tissue correlates negatively with nutritional status and prognostic survival in cachexia patients with gastric cancer

BACKGROUND

Browning of white adipose tissue is a crucial factor contributing to adipose loss in cachexia patients, detectable via 18F-Fluorodeoxyglucose (18F-FDG) uptake. The present study elucidates the clinical relevance of 18F-FDG uptake in the subcutaneous adipose tissue of gastric cancer patients, specifically focusing on adipose browning and its implications on patient clinical parameters and prognosis.

METHODS

This investigation encompassed 770 gastric cancer patients, with PET-CT imaging and clinical data meticulously combined. The 18F-FDG uptake in subcutaneous adipose tissue at the third lumbar layer was quantified, and its correlation with clinical parameters, particularly those related to nutritional status and fat metabolism, was examined. Kaplan-Meier curves were subsequently employed to probe the relationship between 18F-FDG uptake and overall survival.

RESULTS

Of the 770 gastric cancer patients, 252 exhibited cancer-associated cachexia, while 518 did not. Cachectic patients demonstrated elevated 18F-FDG uptake in subcutaneous adipose tissue relative to non-cachectic patients (P < 0.001). Increased 18F-FDG uptake was also correlated with reduced plasma concentrations of albumin, prealbumin, hemoglobin, platelets, cholesterol, apolipoprotein A, low-density lipoprotein, and elevated IL-6 concentrations (all P < 0.05). A significant inverse correlation was observed between 18F-FDG uptake and BMI, albumin, low-density lipoprotein, cholesterol, and apolipoprotein A (all P < 0.05). Patients with higher 18F-FDG uptake exhibited diminished overall survival rates compared to those with lower 18F-FDG uptake (P = 0.0065). Furthermore, 18F-FDG uptake in subcutaneous adipose tissue was an independent prognostic indicator in gastric cancer patients (P = 0.028).

CONCLUSIONS

Browning of subcutaneous adipose tissue was markedly elevated in cachectic gastric cancer patients compared to non-cachectic counterparts. Increased 18F-FDG uptake in subcutaneous adipose tissue in cachectic gastric cancer patients was inversely correlated with nutritional status and survival prognosis.

Profiling of Skeletal Muscle and Adipose Tissue Depots in Men with Advanced Prostate Cancer Receiving Different Forms of Androgen Deprivation Therapy

Background

Androgen deprivation therapy (ADT) is a common treatment modality for men with prostate cancer. Increases in adipose tissue mass and decreases in skeletal muscle mass are known on-target adverse effects of standard ADT. The effects of newer agents such as abiraterone acetate (ABI) and enzalutamide (ENZA) on body composition and how these compare with standard luteinizing hormone-releasing hormone agonists (aLHRHs) are unclear.

Objective

To assess the effects of different forms of androgen deprivation therapy on body composition in men with prostate cancer.

Design setting and participants

Using a retrospective design, 229 patients receiving aLHRHs alone (n = 120) or in combination with ABI (n = 53) or ENZA (n = 56) were studied.

Outcome measurements and statistical analysis

Muscle, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were assessed at baseline, 6 mo, and 18 mo after initiating therapy using a cross-sectional densitometry analysis performed on standard of care computed tomography images. Response trajectories for all treatment groups were calculated via a two-way analysis of variance post hoc test, for both within-group and between-group differences.

Results and limitations

Treatment with aLHRHs, ABI, and ENZA was associated with a median muscle volume loss of -1.4%, -4.8%, and -5.5% at 6 mo, and -7.1%, -8.1%, and -8.3% at 18 mo, respectively. Therapy with aLHRHs was associated with minimal changes in VAT (0.3% at 6 mo and -0.1% at 18 mo). ABI therapy was associated with significant increases in VAT at 6 mo (4.9%) but not at 18 mo (0.5%), and ENZA therapy was associated with significant decreases in VAT (-4.6% at 6 mo and -5.4% at 18 mo). With respect to SAT, treatment with aLHRHs was associated with increases over time (8.6% at 6 mo and 4.7% at 18 mo), ABI was associated with decreases over time (-3.6% at 6 mo and -6.8% at 18 mo), and ENZA had no clear effects (1.7% at 6 mo and 3.3% at 18 mo).

Conclusions

ADT regimens cause significant short-term losses in muscle mass, with the most rapid effects occurring with ABI and ENZA. The three regimens have disparate effects on SAT and VAT, suggesting distinct roles of androgens in these tissues.

Patient summary

Androgen deprivation therapy alters body composition in men with prostate cancer. Abiraterone and enzalutamide are associated with losses in muscle mass compared with luteinizing hormone-releasing hormone agonists. These treatments impact subcutaneous and visceral fat mass, suggesting distinct roles of androgens in these tissues.

Gender-specific associations between abdominal adipose mass and bone mineral density in the middle-aged US population

OBJECTIVES

The relationship between abdominal adipose tissue and osteoporosis is poorly understood. The purpose of this study was to examine the associations of abdominal adipose tissue with bone mineral density (BMD) among a nationally representative sample of US middle-aged adults.

MATERIAL AND METHODS

This study included 1498 participants from the National Health and Nutrition Examination Survey 2013-2014 and 2017-2018. Dual-energy x-ray absorptiometry was used to measure BMD at the lumbar spine and femoral neck, as well as to assess abdominal adipose mass by categorizing total adipose tissue (TAT) into visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). Linear regression was used to assess the relationship between abdominal adipose tissue and BMD, and logistic regression and generalized additive model were used to assess the associations of abdominal adipose tissue with the development of low BMD.

RESULTS

In our study, men accounted for 51.3%, and the mean age and body mass index for men and women were 49.3 and 49.6 years, and 23.9 and 28.3 kg/m2, respectively. In the univariate model, we found that abdominal adipose mass was positively associated with BMD at femoral neck and spine in both genders. In the multivariate model, among men, a negative correlation was observed between TAT and SAT and BMD at the femoral neck. Additionally, higher masses of TAT, SAT, and VAT were found to significantly increase the risk of low BMD at both the femoral neck and lumbar spine. In contrast, there was no significant association between abdominal adipose mass and BMD in middle-aged women, regardless of menopausal status.

CONCLUSIONS

Our finding suggested that abdominal adipose tissue, regardless of its location (SAT or VAT), may have a negative impact on BMD in middle-aged men independently of body weight, but this relationship was not observed in women. Further research is needed to confirm these findings and investigate potential mechanisms underlying these associations.

Assessment of synthetic musks, polychlorinated biphenyls and brominated flame retardants in adipose tissue of obese northern Portuguese women - Metabolic implications

Obesity is a worldwide multifactorial disease linked to persistent pollutants exposure amongst other factors. Humans are daily exposed to an assort of pollutants, such as polychlorinated biphenyls, brominated flame retardants and synthetic musks. These, also known as endocrine disruptors, were all found in human adipose tissue, the preferable matrix for the assessment of long-time accumulation. There are several accounts of hazardous effects of polychlorinated biphenyls and brominated flame retardants on the human organism, whereas for synthetic musks little is still known. Hence, in this study, the levels of polychlorinated biphenyls, brominated flame retardants, and synthetic musks were measured in samples of adipose tissue from 188 Obese Portuguese Women (subcutaneous or scAT and visceral or vAT). After which, associations between pollutants levels and several biochemical parameters from assorted of metabolic processes were studied. Brominated flame retardants were not found in any sample analysed, synthetic musks were found in all the samples analysed (100 % detection frequency) with median levels of 0.4 ± 0.6 μg/g in scAT and 0.4 ± 0.7 μg/g in vAT and polychlorinated biphenyls were found in the majority of samples (<90 % detection frequency) with median levels of 0.1 ± 0.3 μg/g in both tissues. Median concentrations of synthetic musks and polychlorinated biphenyls were similar between scAT and vAT. In total 315 associations were achieved with pollutants levels in adipose tissue, including 273 Spearman's correlations (146 negative and 127 positive). Additionally, 3 multiple linear regressions were achieved. Synthetic musks behave differently than polychlorinated biphenyls and other well-known persistent pollutants in the human body. Synthetic musks behaviour is yet poorly known and their high levels and detection frequencies enforces the need for more studies about their impact on human health. Understanding how these chemicals alter the metabolism is crucial knowledge and hopefully will contribute to improving the treatment and follow-up of obesity in the female population.

Adiposity-associated atrial fibrillation: molecular determinants, mechanisms, and clinical significance

Obesity is an important contributing factor to the pathophysiology of atrial fibrillation (AF) and its complications by causing systemic changes, such as altered haemodynamic, increased sympathetic tone, and low-grade chronic inflammatory state. In addition, adipose tissue is a metabolically active organ that comprises various types of fat deposits with discrete composition and localization that show distinct functions. Fatty tissue differentially affects the evolution of AF, with highly secretory active visceral fat surrounding the heart generally having a more potent influence than the rather inert subcutaneous fat. A variety of proinflammatory, profibrotic, and vasoconstrictive mediators are secreted by adipose tissue, particularly originating from cardiac fat, that promote atrial remodelling and increase the susceptibility to AF. In this review, we address the role of obesity-related factors and in particular specific adipose tissue depots in driving AF risk. We discuss the distinct effects of key secreted adipokines from different adipose tissue depots and their participation in cardiac remodelling. The possible mechanistic basis and molecular determinants of adiposity-related AF are discussed, and finally, we highlight important gaps in current knowledge, areas requiring future investigation, and implications for clinical management.

Parameters of body composition and creeping fat are associated with activity of Crohn's disease

AIM

This study aimed at assessing body composition parameters, creeping fat (CrF), and Crohn's disease's (CD) activity based on the Magnetic Resonance Index of Activity (MaRIA).

METHODS

114 CD patients who underwent magnetic resonance enterography (MRE) between June 2010 and April 2020 were retrospectively assessed. The semi-automated body composition segmentation, the qualitative evaluation of CrF, and MaRIA were performed. Based on their MaRIA score, patients were divided into two groups: mild-to-moderate disease (MaRIA <11, n = 50) and severe disease (MaRIA ≥11, n = 64). MRE parameters were analyzed between both groups. Patients were dichotomized according to body composition categories and the presence of CrF. Univariate regression analyses were performed to investigate the association between dichotomized variables and severe disease. Significant variables were incorporated into the multivariate logistic regression model.

RESULTS

The severe disease group exhibited higher serum C-reactive protein (CRP) levels compared to the mild-to-moderate disease group (p ≤0.001). In the mild-to-moderate disease group, a higher proportion of patients had a body mass index (BMI) ≥ 25 (kg/m²) (32.0%) compared to the severe disease group (16.5%) (p = 0.04). The subcutaneous adipose tissue index (SATI) was significantly higher in the mild-to-moderate disease group (p = 0.04). The visceral to subcutaneous adipose tissue (VAT/SAT) ratio tended to be higher in the severe disease group (p = 0.09). There was no significant difference between both groups regarding total adipose tissue index (TATI) (p = 0.10), visceral adipose tissue index (VATI) (p = 0.51), intramuscular adipose tissue index (IMATI) (p = 0.38), skeletal muscle index (SMI) (p = 0.83), and sarcopenia (p = 0.75). In the multivariate analysis, CrF was significantly associated with severe disease (odds ratio [OR] 11.50, 95% confidence interval [CI] 3.13-42.17; p ≤0.001). Additionally, a BMI ≥ 25 (kg/m²) was protective against severe disease (OR: 0.34, 95% CI 0.12-0.95; p = 0.04).

CONCLUSION

CrF is significantly associated with CD activity.

Abdominal fat and muscle distributions in different stages of colorectal cancer

BACKGROUND

The purpose of this study is to explore the difference of abdominal fat and muscle composition, especially subcutaneous and visceral adipose tissue, in different stages of colorectal cancer (CRC).

MATERIALS AND METHODS

Patients were divided into 4 groups: healthy controls (patients without colorectal polyp), polyp group (patients with colorectal polyp), cancer group (CRC patients without cachexia), and cachexia group (CRC patients with cachexia). Skeletal muscle (SM), subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and intermuscular adipose tissue (IMAT) were assessed at the third lumbar level on computed tomography images obtained within 30 days before colonoscopy or surgery. One-way ANOVA and linear regression were used to analyze the difference of abdominal fat and muscle composition in different stages of CRC.

RESULTS

A total of 1513 patients were divided into healthy controls, polyp group, cancer group, and cachexia group, respectively. In the development of CRC from normal mucosa to polyp and cancer, the VAT area of the polyp group was significantly higher than that of the healthy controls both in male (156.32 ± 69.71 cm² vs. 141.97 ± 79.40 cm², P = 0.014) and female patients (108.69 ± 53.95 cm² vs. 96.28 ± 46.70 cm², P = 0.044). However, no significant differences were observed of SAT area between polyp group and healthy controls in both sexes. SAT area decreased significantly in the male cancer group compared with the polyp group (111.16 ± 46.98 cm² vs. 126.40 ± 43.52 cm², P = 0.001), while no such change was observed in female patients. When compared with healthy controls, the SM, IMAT, SAT, and VAT areas of cachexia group was significantly decreased by 9.25 cm² (95% CI: 5.39-13.11 cm², P < 0.001), 1.93 cm² (95% CI: 0.54-3.32 cm², P = 0.001), 28.84 cm² (95% CI: 17.84-39.83 cm², P < 0.001), and 31.31 cm² (95% CI: 18.12-44.51 cm², P < 0.001) after adjusting for age and gender.

CONCLUSION

Abdominal fat and muscle composition, especially SAT and VAT, was differently distributed in different stages of CRC. It is necessary to pay attention to the different roles of subcutaneous and visceral adipose tissue in the development of CRC.

Are paraspinal muscle quantity, lumbar indentation value, and subcutaneous fat thickness related to disc degeneration? An MRI-based study

INTRODUCTION

The aim of the study was to investigate the relationship between lumbar disc herniation and Goutallier classification (GC), lumbar indentation value, and subcutaneous adipose tissue thickness.

METHODS

102 consecutive patients (59 female and 43 male) with lumbar back pain, numbness, tingling, or pain in the lower extremity indicating radiculopathy who had undergone lumbar magnetic resonance imaging (MRI) and had an intervertebral disc herniation in the L4-5 level, were included in the study. 102 patients who have undergone lumbar MRI in the same time period and have no disc herniation were chosen to be the control group and were selected so as to match the herniated group for sex and age. All these patients' scans were re-interpreted regarding paraspinal muscle atrophy (using the GC), lumbar indentation value, and subcutaneous adipose tissue thickness in the L4-5 level.

RESULTS

The Goutallier score was higher in the herniated group, compared with the non-herniated group (p < 0.001). There was no statistical difference between herniated and non-herniated groups regarding lumbar indentation value (LIV) and subcutaneous adipose tissue thickness (SATT). A Goutallier score of 1.5 provided the highest sensitivity x specificity value to indicate the disc herniation according to the statistical results. The individuals with a Goutallier score of 2, 3, and 4 have 2.87 times more likely to have disc herniation in their MRIs than the ones with a score of 0 and 1.

CONCLUSION

Paraspinal muscle atrophy seems to be related to the presence of disc herniations. The cut-off value of GC to indicate the disc herniation in this study might be useful to predict the risk for disc herniation regarding the Goutallier score. The LIV and SATT measured in magnetic resonance images were randomly distributed between individuals with herniated and non-herniated groups, and statistically, no relationship was observed between these groups regarding these parameters.

IMPLICATIONS FOR PRACTICE

The effect of the parameters studied in this research on disc herniations are expected to be an added value to the literature. The awareness of risk factors for intervertebral disc herniations might be used in preventive medicine to predict the risk and understand the tendency of an individual for disc herniations to occur in the future. Further investigations are needed to establish whether there is a causal relationship or correlation between these parameters and disc herniation.

Inflammation biomarkers and inflammatory genes expression in metabolically healthy obese patients

BACKGROUND AND AIMS

Obesity without metabolic alterations (Metabolically Healthy Obesity, MHO) is a condition with a risk of death and cardiovascular disease lower than that of obesity associated with metabolic alterations (Metabolically Unhealthy Obesity, MUO) and similar to that of healthy non obese individuals. Inflammation is considered as a key risk factor mediating the adverse health outcomes in obesity.

METHODS AND RESULTS

We compared circulating levels of thirteen major cytokines and adipokines and the expression profiles of fifteen pro-inflammatory and two anti-inflammatory genes in visceral and subcutaneous adipose tissue in a series of 16 MHO patients and in 32 MUO patients that underwent bariatric surgery. MHO was defined according to the most applied definition in current literature. Serum levels of a large set of major cytokines and adipokines did not differ between MHO and MUO patients (p ≥ 0.15). Analyses of the expression profile of pro-inflammatory and anti-inflammatory genes in subcutaneous and visceral adipose tissue failed to show differences between MHO and MUO patients (p ≥ 0.07). Sensitivity analyses applying two additional definitions of MHO confirmed the results of the primary analysis.

CONCLUSION

In a series of metabolically healthy obese patients neither circulating levels of major cytokines and adipokines nor the gene expression profile of a large set of pro-inflammatory and anti-inflammatory genes in subcutaneous and visceral fat differed from those in metabolically unhealthy obese patients.

Fully automated CT-based adiposity assessment: comparison of the L1 and L3 vertebral levels for opportunistic prediction

PURPOSE

The purpose of this study is to compare fully automated CT-based measures of adipose tissue at the L1 level versus the standard L3 level for predicting mortality, which would allow for use at both chest (L1) and abdominal (L3) CT.

METHODS

This retrospective study of 9066 asymptomatic adults (mean age, 57.1 ± 7.8 [SD] years; 4020 men, 5046 women) undergoing unenhanced low-dose abdominal CT for colorectal cancer screening. A previously validated artificial intelligence (AI) tool was used to assess cross-sectional visceral and subcutaneous adipose tissue areas (SAT and VAT), as well as their ratio (VSR) at the L1 and L3 levels. Post-CT survival prediction was compared using area under the ROC curve (ROC AUC) and hazard ratios (HRs).

RESULTS

Median clinical follow-up interval after CT was 8.8 years (interquartile range, 5.2-11.6 years), during which 5.9% died (532/9066). No significant difference (p > 0.05) for mortality was observed between L1 and L3 VAT and SAT at 10-year ROC AUC. However, L3 measures were significantly better for VSR at 10-year AUC (p < 0.001). HRs comparing worst-to-best quartiles for mortality at L1 vs. L3 were 2.12 (95% CI, 1.65-2.72) and 2.22 (1.74-2.83) for VAT; 1.20 (0.95-1.52) and 1.16 (0.92-1.46) for SAT; and 2.26 (1.7-2.93) and 3.05 (2.32-4.01) for VSR. In women, the corresponding HRs for VSR were 2.58 (1.80-3.69) (L1) and 4.49 (2.98-6.78) (L3).

CONCLUSION

Automated CT-based measures of visceral fat (VAT and VSR) at L1 are predictive of survival, although overall measures of adiposity at L1 level are somewhat inferior to the standard L3-level measures. Utilizing predictive L1-level fat measures could expand opportunistic screening to chest CT imaging.

U-shaped relationship between subcutaneous adipose tissue index and mortality in liver cirrhosis

BACKGROUND

Subcutaneous and visceral adipose tissues are important body components, but their effects on the mortality in patients with liver cirrhosis remain controversial based on the current evidence.

METHODS

We retrospectively identified 372 eligible patients in whom subcutaneous adipose tissue index (SATI) and visceral adipose tissue index (VATI) could be measured by computed tomography images at the third lumbar vertebra. The association of SATI and VATI with the risk of death was evaluated on a continuous scale with restricted cubic spline curves based on Cox proportional hazards models. Cumulative probability of mortality was estimated by Nelson-Aalen cumulative risk curve analyses. Independent predictors of death were evaluated by competing risk analyses after adjusting for age, sex, and model for end-stage liver disease score.

RESULTS

Majority of patients were male (69.4%) with a mean age of 55.40 ± 10.68 years. SATI had a U-shaped association with mortality (P for non-linearity <0.001). Cutoff values of SATI were 19.7 and 51.8 cm² /m² at the points where hazard ratios were just <1.2. SATI was categorized as low (<19.7 cm² /m² ), moderate (19.7-51.8 cm² /m² ), and high (>51.8 cm² /m² ) level. There was no significant difference in the cumulative probability of mortality between low versus moderate SATI groups (Gray's test, P = 0.052) and high versus moderate SATI groups (Gray's test, P = 0.054). Competing risk analyses demonstrated that low SATI could increase the mortality compared with moderate SATI (subdistribution hazard ratio [sHR] = 1.66, 95% confidence interval [CI]: 0.992-2.78, P = 0.054) and was an independent predictor of death (sHR = 1.86, 95% CI: 1.059-3.28, P = 0.031). Competing risk analyses also demonstrated that high SATI could significantly increase the mortality compared with moderate SATI (sHR = 1.6, 95% CI: 1-2.54, P = 0.049), and was an independent predictor of death (sHR = 2.007, 95% CI: 1.195-3.37, P = 0.0085). VATI had an irregularly shaped association with mortality (P for non-linearity <0.001). Cutoff values of VATI were 9.8 and 40.2 cm² /m² at the points where hazard ratios were just <1.2. VATI was categorized as low (<9.8 cm² /m² ), moderate (9.8-40.2 cm² /m² ), and high (>40.2 cm² /m² ) level. There was no significant difference in the cumulative probability of mortality between low versus moderate VATI groups (Gray's test, P = 0.381) and high versus moderate VATI groups (Gray's test, P = 0.787). Competing risk analyses demonstrated that neither low (sHR = 1.27, 95% CI: 0.599-2.7, P = 0.53) nor high VATI (sHR = 0.848, 95% CI: 0.539-1.34, P = 0.48) was an independent predictor of death compared with moderate VATI.

CONCLUSIONS

Both excessive deficiency and accumulation of subcutaneous adipose tissues negatively influence the outcomes of cirrhotic patients.

Body Composition Predictors of Complicated Crohn's Disease

BACKGROUND

High visceral adipose tissue (VAT) and creeping fat (CrF) in Crohn's disease (CD) have been widely recognized. The VAT to subcutaneous adipose tissue (SAT) ratio and sarcopenia have been associated with CD complications. Studies regarding the influence of body composition predictors on CD complications assessed with magnetic resonance enterography (MRE) are scarce.

AIM

The aim of this study was to assess body composition parameters and CrF in opportunistic MRE as predictors of complicated CD.

METHODS

This was a retrospective study of 114 patients with inflammatory (n = 54) and complicated (n = 60) CD. The semiautomated assessment of body composition and the qualitative evaluation of CrF were performed.

RESULTS

Body composition parameters did not differ between both groups regarding the body mass index (p = 0.50), total adipose tissue index (TATI) (p = 0.14), subcutaneous adipose tissue index (SATI) (p = 0.17), visceral adipose tissue index (VATI) (p = 0.33), VAT/SAT ratio (p = 0.77), intramuscular adipose tissue (p = 0.64), skeletal muscle index (p = 0.22), and sarcopenia (p = 0.50). 47 strictures, 18 fistulae, and seven abscesses were identified. Fistulae were more likely to occur in patients with CrF (odds ratio [OR] 5.07, 95% confidence interval [CI] 1.76-14.56; p=<0.001) and high VAT/SAT ratio (OR: 3.82, 95% CI 1.34-10.85; p = 0.01).

CONCLUSION

Body composition measurements in CD patients displayed no statistically significant difference between the groups of inflammatory and complicated disease. Nonetheless, CD patients stratified in the group of high VAT/SAT ratio and the presence of CrF should be recognized as risk groups for the occurrence of fistulae.

Baseline gene expression in subcutaneous adipose tissue predicts diet-induced weight loss in individuals with obesity

Background

Weight loss effectively reduces cardiometabolic health risks among people with overweight and obesity, but inter-individual variability in weight loss maintenance is large. Here we studied whether baseline gene expression in subcutaneous adipose tissue predicts diet-induced weight loss success.

Methods

Within the 8-month multicenter dietary intervention study DiOGenes, we classified a low weight-losers (low-WL) group and a high-WL group based on median weight loss percentage (9.9%) from 281 individuals. Using RNA sequencing, we identified the significantly differentially expressed genes between high-WL and low-WL at baseline and their enriched pathways. We used this information together with support vector machines with linear kernel to build classifier models that predict the weight loss classes.

Results

Prediction models based on a selection of genes that are associated with the discovered pathways 'lipid metabolism' (max AUC = 0.74, 95% CI [0.62-0.86]) and 'response to virus' (max AUC = 0.72, 95% CI [0.61-0.83]) predicted the weight-loss classes high-WL/low-WL significantly better than models based on randomly selected genes (P < 0.01). The performance of the models based on 'response to virus' genes is highly dependent on those genes that are also associated with lipid metabolism. Incorporation of baseline clinical factors into these models did not noticeably enhance the model performance in most of the runs. This study demonstrates that baseline adipose tissue gene expression data, together with supervised machine learning, facilitates the characterization of the determinants of successful weight loss.

Oleic acid regulates the circadian rhythm of adipose tissue in obesity

The effect of oleic acid (OA) on the regulation of the circadian rhythm present in human visceral (VAT) and subcutaneous (SAT) adipose tissue from patients with morbid obesity has not been analyzed yet. VAT and SAT explants from patients with morbid obesity were incubated with OA to analyze the circadian regulation of clock and other genes related to lipid metabolism (SREBP-1c, FAS, LPL and CPT1), and their association with baseline variables and the improvement of these patients after bariatric surgery. There were significant differences in amplitude and acrophase in VAT with respect to SAT. In VAT, body weight negatively correlated with BMAL1 and CRY1 amplitude, and REVERBα acrophase; body mass index (BMI) negatively correlated with REVERBα acrophase; and waist circumference negatively correlated with PER3 acrophase. In SAT, BMI negatively correlated with CLOCK amplitude, and CLOCK, REVERBα and CRY2 MESOR; and waist circumference negatively correlated with PER3 amplitude and acrophase. A greater short-term improvement of body weight, BMI and waist circumference in patients with morbid obesity after bariatric surgery was associated with a lower CRY1 and CRY2 amplitude and an earlier PER1 and PER3 acrophase in SAT. OA produced a more relevant circadian rhythm and increased the amplitude of most clock genes and lipid metabolism-related genes. OA regulated the acrophase of most clock genes in VAT and SAT, placing CLOCK/BMAL1 in antiphase with regard to the other genes. OA increased the circadian rhythmicity, although with slight differences between adipose tissues. These differences could determine its different behavior in obesity.

Prognostic value of SAT volume and density for predicting the outcome of patients with unresectable HCC treated with lenvatinib plus anti-PD-1 antibodies

The combination of immunotherapy and lenvatinib has shown a good response for inoperable hepatocellular carcinoma (HCC) patients. However, a specific marker to predict the response, overall survival (OS) and progression-free survival (PFS) of this combination treatment is lacking. The present work focused on investigating whether subcutaneous adipose tissue (SAT) characteristics on CT could predict the response and survival for HCC patients who receive the combination treatment. This study retrospectively enrolled 100 patients with inoperable HCC who received lenvatinib combined with anti-PD-1 antibody treatment from 2018 to 2022. Fifty-six patients were finally included. The area and density of SAT were measured using unenhanced cross-sectional CT images. The SAT volume index was calculated as the SAT area divided by height squared in meters (cm²/m²). We classified these patients into two groups according to SAT volume index and density. Twenty-one patients (37.5%) with a low SAT volume index and high density were divided into the high risk group. High risk patients showed a markedly decreased objective response rate (ORR) compared with low risk patients (19.0% versus 54.3%, P = 0.021). The median PFS times were 6.00 and 12.03 months for the high risk and low risk groups, respectively (hazard ratio (HR) = 2.296, P = 0.035). High risk patients with Barcelona Clinic Liver Cancer (BCLC) stage-C had a markedly decreased OS of compared to low risk patients (HR = 4.272, P = 0.01). Patients with low SAT volume index and high density were found to have less opportunity to benefit from this combination therapy.

Evaluation of the relationship between abdominal fat distribution and osteoporotic vertebral compression fracture with MRI

OBJECTIVE

This study was carried out to investigate the effects of abdominal subcutaneous adiposity and visceral adiposity on osteoporotic compression fractures.

MATERIAL AND METHODS

The study group consisted of a total of 152 individuals aged 50-80 years; 76 were included in the vertebral fracture group and 76 in the healthy control group, whose bone mineral density was calculated. In order to determine the distribution of abdominal fat in both groups, four different measurements, i.e., sagittal abdominal diameter (SAD), abdominal diameter (AD), ventral subcutaneous thickness (VST), and dorsal subcutaneous thickness (DST), were made using lumbar magnetic resonance imaging (MRI). The visceral fat ratio (VFR) was also calculated based on these measurements.

RESULTS

There was a significant difference between the patient and control groups in VST and DST values, both when gender distribution was and was not taken into account (p < 0.006 for all cases). There was no significant difference between the patient and control groups in SAD and AS values, both when only female patients were considered, and gender distribution was not taken into account (p > 0.25 for all cases). On the other hand, in the analysis, when only male patients were considered, the SAD and AD values of the patient group were found to be significantly lower than those of the control group (p = 0.046 and p = 0.048, respectively).

CONCLUSION

In conclusion, the study findings indicated that high SAD values in the male gender and high VST and DST values in both genders were associated with low lumbar vertebral fracture risk.

Adipose tissue radiodensity and mortality among patients with nonmetastatic breast cancer

BACKGROUND & AIMS

Computed tomography (CT) scans can measure quantity and distribution of adipose tissue, which are associated with breast cancer prognosis. As a novel prognostic marker, radiodensity of adipose tissue has been examined in multiple cancer types, but never in breast cancer. Lower density indicates larger adipocytes with greater lipid content, whereas higher density can reflect inflammation, fibrosis, vascularity, or even metabolic changes; and both may impact breast cancer prognosis.

METHODS

We included 2868 nonmetastatic patients with breast cancer diagnosed between January 2005 and December 2013 at Kaiser Permanente Northern California, an integrated healthcare system. From CT scans at diagnosis, we assessed the radiodensity of subcutaneous (SAT) and visceral adipose tissue (VAT) at the third lumbar vertebra and categorized their radiodensity into three levels: low (<1 standard deviation [SD] below the mean), middle (mean ± 1 SD), and high (>1 SD above the mean). Using multivariable Cox proportional hazards regression with adjustment for clinicopathological characteristics including body mass index, we calculated hazard ratios (HRs [95% confidence intervals]) for the associations of adipose tissue radiodensity with overall mortality and breast-cancer-specific mortality.

RESULTS

Median age at diagnosis of breast cancer was 56.0 years, most (63.3%) were non-Hispanic White and nearly half (45.6%) were stage II. Compared to middle SAT radiodensity, high SAT radiodensity was significantly associated with increased risk of overall mortality (HR: 1.45 [1.15-1.81]), non-significantly with breast-cancer-specific mortality (HR: 1.32 [0.95-1.84]). Neither low SAT radiodensity nor high or low VAT radiodensity was significantly associated with overall or breast-cancer-specific mortality.

CONCLUSIONS

High radiodensity of SAT at diagnosis of nonmetastatic breast cancer was associated with increased risk of overall mortality, independent of adiposity and other prognostic factors. Considering both radiodensity and quantity of adipose tissue at different locations could deepen understanding of the role of adiposity in breast cancer survival.

Discovery of a novel anti-obesity meroterpenoid agent targeted subcutaneous adipose tissue

BACKGROUND

Meroterpenoid furanasperterpene A (T2-3) with a novel 6/6/6/6/5 pentacyclic skeleton was isolated from the Aspergillus terreus GZU-31-1. Previously, we showed that T2-3 possessed significant lipid-lowering effects in 3T3-L1 adipocytes at 5 μM concentration. However, its therapeutic effect in metabolic disease and the underlying mechanisms of action remain unclear.

METHODS

High fat diet-induced obesity (DIO) mouse model and 3T3-L1 cell model were used to assess the anti-obesity effects of T2-3. Lipids in the adipocytes were examined by Oil Red O staining. β-catenin expression was examined by immunofluorescence and Western blotting, its activity was assessed by TOPflash/FOPflash assay.

RESULTS

T2-3 possessed potent anti-obesity effects in DIO mice, it significantly reduced body weight and subcutaneous adipose tissue (SAT) mass. Mechanistic studies showed that T2-3 significantly inhibited 3T3-L1 preadipocyte differentiation as indicated by the reduced number of mature adipocytes. The treatments also reduced the expressions of critical adipogenic transcription factors CEBP-α and PPAR-γ in both 3T3-L1 adipocytes and SAT in DIO mice. Interestingly, T2-3 increased the cytoplasmic and nuclear expressions of β-catenin and the transcriptional activity of β-catenin in 3T3-L1 adipocytes; the elevated β-catenin expression was also observed in SAT of the T2-3-treated DIO mice. Indeed, upregulation of β-catenin activity suppressed adipogenesis, while β-catenin inhibitor JW67 reversed the anti-adipogenic effect of T2-3. Taken together, our data suggest that T2-3 inhibits adipogenesis by upregulating β-catenin activity.

CONCLUSIONS

Our study is the first report demonstrating meroterpenoid furanasperterpene A as a novel 6/6/6/6/5 pentacyclic skeleton (T2-3) that possesses potent anti-adipogenic effect by targeting β-catenin signaling pathway. Our findings drive new anti-obesity drug discovery and provide drug leads for chemists and pharmacologists.

Analysis of different adipose depot gene expression in cachectic patients with gastric cancer

Purpose

This study aimed to identify the differentially expressed genes (DEGs) that contributed to the different amount of fat loss between subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) among cachectic patients.

Methods

RNA sequencing was performed and bioinformatic tools were utilized to analyze the biological functions and construct regulation networks of DEGs. We presumed that iroquois homeobox 1 (IRX1) to be a hub gene and analyzed its clinical significance. Mouse model of cancer cachexia was established and differences between SAT and VAT were compared. The function of IRX1 on lipid metabolism was clarified by Oil Red O staining, qRT-PCR, and Western blotting in adipocytes.

Results

A total of 455 DEGs were screened between SAT and VAT in cachectic patients. Several hub genes were selected and IRX1 was presumed to contribute to the pathological difference between SAT and VAT in cancer cachexia. Patients with higher expression of IRX1 in SAT than VAT revealed significantly higher weight loss, IL-6 and TNF-α, as well as lower BMI, SAT, and VAT area. IRX1 expression in SAT was negatively correlated with SAT area. In cachectic mice, the expression of IRX1 in SAT was significantly higher than that in VAT. The inhibition effect on adipogenesis exerted by IRX1 was also proved in vitro.

Conclusion

These data supported that DEGs contribute to the different degrees of fat loss among adipose depots in cachectic patients. IRX1 in SAT promoted fat loss by inhibiting adipocyte differentiation and adipogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-022-00708-x.

MRI adipose tissue segmentation and quantification in R (RAdipoSeg)

BACKGROUND

Excess adipose tissue is associated with increased cardiovascular and metabolic risk, but the volume of visceral and subcutaneous adipose tissue poses different metabolic risks. MRI with fat suppression can be used to accurately quantify adipose depots. We have developed a new semi-automatic method, RAdipoSeg, for MRI adipose tissue segmentation and quantification in the free and open source statistical software R.

METHODS

MRI images were obtained from wild-type mice on high- or low-fat diet, and from 20 human subjects without clinical signs of metabolic dysfunction. For each mouse and human subject, respectively, 10 images were segmented with RAdipoSeg and with the commercially available software SliceOmatic. Jaccard difference, relative volume difference and Spearman's rank correlation coefficients were calculated for each group. Agreement between the two methods were analysed with Bland-Altman plots.

RESULTS

RAdipoSeg performed similarly to the commercial software. The mean Jaccard differences were 10-29% and the relative volume differences were below ( ±) 20%. Spearman's rank correlation coefficient gave p-values below 0.05 for both mouse and human images. The Bland-Altman plots indicated some systematic and proporitional bias, which can be countered by the flexible nature of the method.

CONCLUSION

RAdipoSeg is a reliable and low cost method for fat segmentation in studies of mice and humans.

Failure of subcutaneous lipectomy to combat metabolic dysregulations in ovariectomy-induced obesity in young female rats

PURPOSE

The deleterious effect of visceral adipose tissue accumulation is well known. However, the recent trend in liposuction is mal-directed toward easily accessible subcutaneous fat for the purpose of body shaping. The aim of the present study is to probe the metabolic effects of subcutaneous abdominal adipose tissue lipectomy in ovariectomized obese rats as well as the role of adipokines in these changes.

METHODS

The study was conducted on young female rats randomized into two main groups according to the duration of the experiment, namely, 5-week and 10-week. Both groups were subdivided as follows: sham-operated, ovariectomized, and ovariectomized lipectomized rat groups. The rats underwent measurement of body weight (BW) and determination of body mass index (BMI). Fasting blood glucose, lipid profile, liver function, plasma malondialdehyde, leptin, and adiponectin were estimated, and the content of both blood and hepatic tissue of reduced glutathione was assessed. In addition, histological study of the liver, aorta, and perirenal fat of all rat groups was performed.

RESULTS

Ovariectomy-induced obesity is marked by a significant increase in BW and BMI. Following subcutaneous lipectomy, the rats exhibited significant weight gain accompanied by fasting hyperglycemia, dyslipidemia, deterioration of synthetic function of the liver, and disturbed oxidant/antioxidant status. Histological examination revealed fatty infiltration of aortic and hepatic tissues.

CONCLUSION

Despite the immediate positive effect of subcutaneous lipectomy for weight loss and/or body shaping, multiple delayed hazards follow the procedure, which should be carefully considered.

Visceral Adipose Tissue Inflammation and Radiographic Visceral-to-Subcutaneous Adipose Tissue Ratio in Patients with Cirrhosis

BACKGROUND AND AIMS

Accumulation of visceral adipose tissue is associated with hepatic inflammation and fibrosis, suggestive of its metabolic and inflammatory properties. We aimed to examine the histologic findings of visceral and subcutaneous adipose tissue and to associate these findings with clinical and radiologic characteristics in patients with cirrhosis.

METHODS

Included were 55 adults with cirrhosis who underwent liver transplantation from 3/2017-12/2018 and had an abdominal computed tomography (CT) scan within 6 months prior to transplant. Visceral-to-subcutaneous adipose tissue ratio (VSR) was calculated using visceral (VATI) and subcutaneous adipose tissue index (SATI) quantified by CT at the L3-vertebral level and normalized for height (cm²/m²). VAT (greater omentum), SAT (abdominal wall), and skeletal muscle (rectus abdominis) biopsies were collected at transplant.

RESULTS

Majority of patients had VAT inflammation (71%); only one patient (2%) had SAT inflammation. Patients with VAT inflammation had similar median VATI (42 vs 41 cm²/m²), lower median SATI (64 vs 97 cm²/m²), and higher median VSR (0.63 vs 0.37, p = 0.002) than patients without inflammation. In univariable logistic regression, VSR was associated with VAT inflammation (OR 1.47, 95%CI 1.11-1.96); this association remained significant even after adjusting for age, sex, BMI, HCC, or MELD-Na on bivariable analyses.

CONCLUSION

In patients with cirrhosis undergoing liver transplantation, histologic VAT inflammation was common, but SAT inflammation was not. Increased VSR was independently associated with VAT inflammation. Given the emerging data demonstrating the prognostic value of VSR, our findings support the value of CT-quantified VSR as a prognostic marker for adverse outcomes in the liver transplant setting.

Molecular remodeling of adipose tissue is associated with metabolic recovery after weight loss surgery

BACKGROUND

Bariatric surgery is an effective therapy for individuals with severe obesity to achieve sustainable weight loss and to reduce comorbidities. Examining the molecular signature of subcutaneous adipose tissue (SAT) following different types of bariatric surgery may help in gaining further insight into their distinct metabolic impact.

RESULTS

Subjects undergoing biliopancreatic diversion with duodenal switch (BPD-DS) showed a significantly higher percentage of total weight loss than those undergoing gastric bypass or sleeve gastrectomy (RYGB + SG) (41.7 ± 4.6 vs 28.2 ± 6.8%; p = 0.00005). Individuals losing more weight were also significantly more prone to achieve both type 2 diabetes and dyslipidemia remission (OR = 0.75; 95%CI = 0.51-0.91; p = 0.03). Whole transcriptome and methylome profiling showed that bariatric surgery induced a profound molecular remodeling of SAT at 12 months postoperative, mainly through gene down-regulation and hypermethylation. The extent of changes observed was greater following BPD-DS, with 61.1% and 49.8% of up- and down-regulated genes, as well as 85.7% and 70.4% of hyper- and hypomethylated genes being exclusive to this procedure, and mostly associated with a marked decrease of immune and inflammatory responses. Weight loss was strongly associated with genes being simultaneously differentially expressed and methylated in BPD-DS, with the strongest association being observed for GPD1L (r² = 0.83; p = 1.4 × 10^-6).

CONCLUSIONS

Present findings point to the greater SAT molecular remodeling following BPD-DS as potentially linked with higher metabolic remission rates. These results will contribute to a better understanding of the metabolic pathways involved in the response to bariatric surgery and will eventually lead to the development of gene targets for the treatment of obesity. Trial registration ClinicalTrials.gov NCT02390973.

The regulation of adipokines related to obesity and diabetes is sensitive to BDNF levels and adipose tissue location

PURPOSE

The role of BDNF in adipose tissue metabolism is poorly understood. We investigated the effects of decreased levels of BDNF on the expression of major adipokines in different fat depots (e.g., subcutaneous and epididymal) of mouse groups fed three different diet protocols.

METHODS

BDNF heterozygous (+ / -) mice were used to evaluate the effect of reduced BDNF levels. Six groups of C57BL/6 J breed wild type (WT) and BDNF (+ / -) mice were formed. These groups were fed, respectively, a control diet (CD), a high-fat diet (HFD), and a high-sucrose diet (HSD) for 4 months. Serum samples and adipose tissues were used for biochemical assays. The serum concentrations and tissue expression levels of leptin, adiponectin, and resistin were measured.

RESULTS

Compared to the CD-fed WT group (control group), serum leptin and leptin expression levels were found to be higher in all experimental groups. Serum adiponectin levels were lower in the BDNF (+ / -) groups and HFD-fed WT group than in the control group. Epididymal adiponectin expression was found to be lower in the HFD-fed BDNF (+ / -) group and higher in HSD-fed groups than in the control group. Compared to the control group, adiponectin expression increased in the WT groups in subcutaneous adipose tissue. Serum resistin levels were elevated in the HFD-fed groups. Resistin expression in epididymal adipose tissue was lower in the CD-fed and HFD-fed groups than in the control group.

CONCLUSIONS

BDNF levels and diet differentially affect the expression of adipokines in different fat tissues in the body. BDNF may play a protective role in obesity and diabetes.

Preoperative Assessment of Abdominal Adipose Tissue to Predict Microvascular Invasion in Small Hepatocellular Carcinoma

BACKGROUND AND AIMS

Microvascular invasion (MVI) affects recurrence after treatment of small hepatocellular carcinoma (sHCC) of ≤3 cm in size. The present study aimed to investigate whether abdominal subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and intermuscular adipose tissue (IMAT) are associated with MVI in patients with sHCC.

METHODS

A total of 124 patients with pathologically-confirmed sHCC diagnosed on surgical resection at the First Hospital Affiliated to Army Military University were recruited and divided into two groups according to MVI classification criteria (i.e., MVI-positive or MVI-negative). The SAT, VAT, and IMAT areas at the lumbar 3 vertebral level were imaged with abdominal computed tomography and measured using ImageJ software. Their association with MVI in sHCC was analyzed.

RESULTS

Of the 124 patients with sHCC, 67 were MVI-positive and 57 were MVI-negative. Univariate analysis revealed a significant difference in the abdominal VAT and SAT between the MVI-positive and MVI-negative groups (p<0.05), with an area under the receiver operating characteristic curve of 0.76 and 0.65, respectively.

CONCLUSIONS

The results of this study suggest that the areas of abdominal SAT and VAT are of significant clinical value because they can effectively predict the MVI status in patients with sHCC.

Altered features of body composition in older adults with type 2 diabetes and prediabetes compared with matched controls

BACKGROUND

Ageing is accompanied by muscle loss and fat gain, which may elevate the risk of type 2 diabetes (T2D). However, there is a paucity of data on the distribution of regional lean and fat tissue in older adults with T2D or prediabetes compared with healthy controls. The objective of this study was to compare regional body composition [by dual-energy x-ray absorptiometry (DXA)], muscle and subcutaneous adipose tissue (SAT) thicknesses (by ultrasound), and ultrasound-based muscle texture features in older adults with T2D or prediabetes compared with normoglycaemic controls.

METHODS

Eighteen adults > 60 years with T2D or prediabetes (T2D group) were individually matched to normoglycaemic participants [healthy matched (HM) group] for age (±5 years), sex, and body fat (±2.5%). In a single study visit, all participants received a whole-body DXA scan and ultrasound assessment of the abdomen and anterior thigh. At these two landmarks, we used ultrasound to measure muscle and SAT thickness, as well as texture features of the rectus femoris and rectus abdominis. We also conducted an exploratory subanalysis on a subset of participants (n = 14/18 in the T2D group and n = 10/18 in the HM group) who underwent additional assessments including strength testing of the knee extensors (using a Biodex dynamometer), and a fasting blood sample for the measurement of circulating markers of glucose metabolism [glucose, insulin, c-peptide, and the homoeostatic model assessment of insulin resistance (HOMA-IR)].

RESULTS

The T2D group was 72 ± 8 years old (mean ± SD), predominantly male (n = 15/18; 83%), and overweight (BMI: 27.8 ± 4.2 kg/m² , 33.2 ± 5.3% body fat). DXA-derived upper arm lean mass was 0.4 kg greater (P = 0.034), and leg fat mass was 1.4 kg lower (P = 0.048), in the T2D vs. HM group. Ultrasound-based texture features were distinct between the groups [rectus abdominis blob size: 0.07 ± 0.06 vs. 0.30 ± 0.43 cm² , P = 0.045; rectus femoris local binary pattern (LBP) entropy: 4.65 ± 0.05 vs. 4.59 ± 0.08 A.U., P = 0.007]. When all participants who underwent additional assessments were pooled (n = 24), we observed that certain ultrasound-based muscle texture features correlated significantly with muscle strength (rectus abdominis histogram skew vs. power during an isokinetic contraction at 60°/s: r = 0.601, P = 0.003) and insulin resistance (rectus femoris LBP entropy vs. HOMA-IR: r = 0.419, P = 0.042).

CONCLUSIONS

Our findings suggest a novel body composition phenotype specific to older adults with T2D or prediabetes. We are also the first to report that ultrasound-based texture features correspond with functional outcomes. Future larger scale studies are needed to uncover the mechanisms underpinning these regional body composition differences.

The NLRP3 inflammasome activation in subcutaneous, epicardial and pericardial adipose tissue in patients with coronary heart disease undergoing coronary by-pass surgery

Background and aims

Epicardial and pericardial adipose tissue (EAT and PAT) associate with atherosclerosis, however, discussed to have different inflammatory properties. We examined the NLRP3 inflammasome related pathway, playing a pivotal role in atherosclerosis, in EAT, PAT and subcutaneous AT (SAT), their relationship to cell types and anthropometric measures in patients undergoing coronary artery bypass grafting.

Methods

Biopsies from EAT, PAT and SAT were collected from 52 patients with coronary heart disease (CHD) (median body weight 85.0 kg) and 22 controls. RNA was extracted and expression of interleukin (IL)-1β, IL-18, NLRP3, Caspase-1, toll-like receptor 4 (TLR4), IL-6, IL-6 receptor and gp130 were analyzed by RT-PCR.

Results

Limited differences in any genes between CHD patients and controls. IL-18 and IL-6 were 4-fold higher expressed in EAT versus PAT (p < 0.01, both) and SAT (p < 0.001, both), whereas caspase-1, IL-6R and gp130 were higher expressed in SAT compared to the other compartments (all p = 0.06-<0.001). Significant correlations between SAT and PAT gene expressions (r = 0.358-0.579, all p ≤ 0.01). Especially NLRP3 and TLR4 associated with the expression of macrophages in all compartments (all p < 0.001). In EAT IL-18 correlated inversely with the expression of macrophages and T-cells. In SAT and PAT most of the mediators associated with body weight.

Conclusions

Higher expression of IL-18 and IL-6 was observed in EAT in our non-obese CHD patients, not related to inflammatory cells. The NLRP3 inflammasome activation in SAT that mirrored PAT, both related to anthropometrics, suggest that SAT samples, being easily available, to a certain degree, represent adipose tissue inflammation in general.

New insights into aging-associated characteristics of female subcutaneous adipose tissue through integrative analysis of multi-omics data

Aging could be critical in limiting the application of subcutaneous adipose tissue (SAT) in tissue repair and reconstruction. However, no systematic study on the characteristics of SAT aging has been conducted. In this study, a scanning electronic microscope was used to detect the structural and compositional changes of SAT collected from nine females in three age groups. Multi-omics data of SAT from 37 females were obtained from Gene Expression Omnibus database, and 1860 genes, 56 miRNAs, and 332 methylated genes were identified as being differentially expressed during aging among non-obese females. Using Weighted Correlation Network Analysis (WGCNA), 1754 DEGs were defined as aging-associated genes for non-obese females, distributed among ten co-expression modules. Through Gene Ontology enrichment analysis and Gene Set enrichment analysis on those aging-associated DEGs, SAT aging was observed to be characterized by variations in immune and inflammatory states, mitochondria, lipid and carbohydrate metabolism, and regulation of vascular development. SUPV3L1, OGT, and ARPC1B were identified as conserved and core SAT-aging-related genes, as verified by RT-qPCR among 18 samples in different age groups. Multi-omics regulatory networks of core aging-associated biological processes of SAT were also constructed. Based on WGCNA, we performed differential co-expression analysis to unveil the differences in aging-related co-expression patterns between obese and non-obese females and determined that obesity could be an important accelerating factor in aging processes. Our work provides a landscape of SAT aging, which could be helpful for further research in fields such as repair and reconstruction as well as aging.

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.

Experimental characterisation of porcine subcutaneous adipose tissue under blunt impact up to irreversible deformation

A deeper understanding of the mechanical characteristics of adipose tissue under large deformation is important for the analysis of blunt force trauma, as adipose tissue alters the stresses and strains that are transferred to subjacent tissues. Hence, results from drop tower tests of subcutaneous adipose tissue are presented (i) to characterise adipose tissue behaviour up to irreversible deformation, (ii) to relate this to the microstructural configuration, (iii) to quantify this deformation and (iv) to provide an analytical basis for computational modelling of adipose tissue under blunt impact. The drop tower experiments are performed exemplarily on porcine subcutaneous adipose tissue specimens for three different impact velocities and two impactor geometries. An approach based on photogrammetry is used to derive 3D representations of the deformation patterns directly after the impact. Median values for maximum impactor acceleration for tests with a flat cylindrical impactor geometry at impact velocities of 886 mm/s, 1253 mm/s and 2426 mm/s amount to 61.1 g, 121.6 g and 264.2 g, respectively, whereas thickness reduction of the specimens after impact amount to 16.7%, 30.5% and 39.3%, respectively. The according values for tests with a spherically shaped impactor at an impact velocity of 1253 mm/s are 184.2 g and 78.7%. Based on these results, it is hypothesised that, in the initial phase of a blunt impact, adipose tissue behaviour is mainly governed by the behaviour of the lipid inside the adipocytes, whereas for further loading, contribution of the extracellular collagen fibre network becomes more dominant.

Automatic segmentation of whole-body adipose tissue from magnetic resonance fat fraction images based on machine learning

OBJECTIVE

To propose a fully automated algorithm, which is implemented to segment subcutaneous adipose tissue (SAT) and internal adipose tissue (IAT) from the total adipose tissue for whole-body fat distribution analysis using proton density fat fraction (PDFF) magnetic resonance images.

MATERIALS AND METHODS

Adipose tissue segmentation was implemented using the U-Net deep neural network model. All datasets were collected using a 3.0 T magnetic resonance imaging (MRI) scanner for whole-body scan of 20 volunteers covering from neck to knee with about 160 images for each volunteer. PDFF images were reconstructed based on chemical-shift-encoded fat-water imaging. After selecting the representative PDFF images (total 906 images), the manual labeling of the SAT area was used for model training (504 images), validation (168 images), and testing (234 images).

RESULTS

The automatic segmentation model was validated through three indices using the validation and test sets. The dice similarity coefficient, precision rate, and recall rate were 0.976 ± 0.048, 0.978 ± 0.048, and 0.978 ± 0.050, respectively, in both validation and test sets.

CONCLUSION

The proposed algorithm can reliably and automatically segment SAT and IAT from whole-body MRI PDFF images. The proposed method provides a simple and automatic tool for whole-body fat distribution analysis to explore the relationship between fat deposition and metabolic-related chronic diseases.

Postnatal exercise protects offspring from high-fat diet-induced reductions in subcutaneous adipocyte beiging in C57Bl6/J mice

Maternal low-protein and postnatal high-fat (HF) diets program offspring obesity and type 2 diabetes mellitus (T2DM) risk by epigenetically reducing beige adipocytes (BAs) via increased G9a protein expression (Histone3 Lysine9 dimethyl transferase), an inhibitor of the BA marker fibroblast growth factor 21 (FGF21). Conversely, offspring exercise reduces fat mass and white adipocytes, but the mechanisms are not yet understood. This work investigated whether exercise reduces offspring obesity and T2DM risk caused by a maternal HF diet via regulation of G9a and FGF21 expression that would convert white to BA. Two-month-old female C57Bl/6J mice (F0) were fed a 16% (normal fat; NF) or a 45% HF diet for 3 months prior to breeding, and subsequent gestation and lactation. Male offspring (F1) were fed the same NF and HF diets and further divided into either sedentary (S) or voluntary wheel running (Ex) groups for an additional 3 months yielding eight groups: NF (maternal treatment condition)-NF-S (postweaning treatment conditions), NF-HF-S, NF-NF-Ex, NF-HF-Ex, HF-NF-S, HF-HF-S, HF-NF-Ex, and HF-HF-Ex. Subcutaneous adipose tissue was collected for protein and mRNA analysis of FGF21, peroxisome proliferator-activated receptor-gamma coactivator (PGC-1 alpha, inducer of FGF21), G9a, E4BP4 (G9a coactivator), and protein expression of H3K9 demethylases (KDM4C). Postnatal HF diet decreased FGF21 positive BA numbers regardless of maternal diets and postnatal exercise. Under sedentary conditions, postnatal HF diet increased protein expression of FGF21 transcription inhibitors G9a and E4BP4 compared to NF diet resulting in decreased FGF21 expression. In contrast, postnatal HF diet and exercise decreased G9a and E4BP4 protein expression while decreasing FGF21 expression compared to NF diet. Under exercised condition, postnatal HF diet-induced KDM4C protein expression while no changes in KDM4C protein expression were induced by postnatal HF diet under sedentary conditions. These findings suggest that the postnatal diet exerts a greater impact on offspring adiposity and BA numbers than maternal diets. These data also suggest that offspring exercise induces KDM4C to counter the increase in G9a that was triggered by maternal and postnatal HF diets. Future studies need to determine whether KDM4C induces methylation status of G9a to alter thermogenic function of BA.

Subcutaneous, but not visceral, adipose tissue as a marker for prognosis in gastric cancer patients with cachexia

BACKGROUND & AIMS

Adipose tissue loss is one of the features in patients with cancer cachexia. However, whether subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) contribute differently to the progress of cancer cachexia in gastric cancer patients with cachexia remains unclear. This study aim to investigate the effect of SAT and VAT in gastric cancer patients with cachexia.

METHODS

Gastric cancer patients who underwent surgery were divided into cancer cachexia group and non-cachexia group. A new deep learning system was developed to segment SAT and VAT from the computed tomography images at the third lumbar vertebra. Indexes of SAT (SATI) and VAT (VATI) were compared between cachexia and non-cachexia groups. The prognostic values of SATI and VATI for patients with gastric cancer cachexia were analyzed by Kaplan-Meier method and Cox regression.

RESULTS

A total of 1627 gastric cancer patients (411 cachexia and 1216 non-cachexia) were included in this study. A new V-Net-Based segmentation deep learning system was developed to quickly (0.02 s/image) and accurately segment SAT (dice scores = 0.96) and VAT (dice scores = 0.98). The SATI of gastric cancer patients with cachexia were significantly lower than non-cachexia patients (44.91 ± 0.90 vs. 50.92 ± 0.71 cm²/m², P < 0.001), whereas no significant difference was detected in VATI (35.98 ± 0.84 VS. 37.90 ± 0.45 cm²/m², P = 0.076). Cachexia patients with low SATI showed poor survival than those with high SATI (HR = 1.35; 95% CI = 1.06-1.74). In contrast, VATI did not show close correlation with survival in patients with cachexia (HR = 1.18; 95% CI = 0.92-1.51).

CONCLUSION

SAT and VAT showed different effects on gastric cancer patients with cachexia. More attention should be paid to the loss of SAT during the progress of cancer cachexia.

Obesity and obesity-induced inflammatory disease contribute to atherosclerosis: a review of the pathophysiology and treatment of obesity

Two billion people worldwide older than 18 years of age, or approximately 30% of the world population, are overweight or obese. In addition, more than 43 million children under the age of 5 are overweight or obese. Among the population in the United States aged 20 and greater, 32.8 percent are overweight and 39.8 percent are obese. Blacks in the United States have the highest age-adjusted prevalence of obesity (49.6%), followed by Hispanics (44.8%), whites (42.2%) and Asians (17.4%). The impact of being overweight or obese on the US economy exceeds $1.7 trillion dollars, which is equivalent to approximately eight percent of the nation's gross domestic product. Obesity causes chronic inflammation that contributes to atherosclerosis and causes >3.4 million deaths/year. The pathophysiologic mechanisms in obesity that contribute to inflammation and atherosclerosis include activation of adipokines/cytokines and increases in aldosterone in the circulation. The adipokines leptin, resistin, IL-6, and monocyte chemoattractant protein activate and chemoattract monocytes/macrophages into adipose tissue that promote visceral adipose and systemic tissue inflammation, oxidative stress, abnormal lipid metabolism, insulin resistance, endothelial dysfunction, and hypercoagulability that contribute to atherosclerosis. In addition in obesity, the adipokines/cytokines IL-1β, IL-18, and TNF are activated and cause endothelial cell dysfunction and hyperpermeability of vascular endothelial junctions. Increased aldosterone in the circulation not only expands the blood volume but also promotes platelet aggregation, vascular endothelial dysfunction, thrombosis, and fibrosis. In order to reduce obesity and obesity-induced inflammation, therapies including diet, medications, and bariatric surgery are discussed that should be considered in patients with BMIs>35-40 kg/m2 if diet and lifestyle interventions fail to achieve weight loss. In addition, antihypertensive therapy, plasma lipid reduction and glucose lowering therapy should be prescribed in obese patients with hypertension, a 10-year CVD risk >7.5%, or prediabetes or diabetes.

CAFT: a deep learning-based comprehensive abdominal fat analysis tool for large cohort studies

BACKGROUND

There is increasing appreciation of the association of obesity beyond co-morbidities, such as cancers, Type 2 diabetes, hypertension, and stroke to also impact upon the muscle to give rise to sarcopenic obesity. Phenotypic knowledge of obesity is crucial for profiling and management of obesity, as different fat-subcutaneous adipose tissue depots (SAT) and visceral adipose tissue depots (VAT) have various degrees of influence on metabolic syndrome and morbidities. Manual segmentation is time consuming and laborious. Study focuses on the development of a deep learning-based, complete data processing pipeline for MRI-based fat analysis, for large cohort studies which include (1) data augmentation and preprocessing (2) model zoo (3) visualization dashboard, and (4) correction tool, for automated quantification of fat compartments SAT and VAT.

METHODS

Our sample comprised 190 healthy community-dwelling older adults from the Geri-LABS study with mean age of 67.85 ± 7.90 years, BMI 23.75 ± 3.65 kg/m², 132 (69.5%) female, and mainly Chinese ethnicity. 3D-modified Dixon T1-weighted gradient-echo MR images were acquired. Residual global aggregation-based 3D U-Net (RGA-U-Net) and standard 3D U-Net were trained to segment SAT, VAT, superficial and deep subcutaneous adipose tissue depots (SSAT and DSAT). Manual segmentation from 26 subjects was used as ground truth during training. Data augmentations, random bias, noise and ghosting were carried out to increase the number of training datasets to 130. Segmentation accuracy was evaluated using Dice and Hausdorff metrics.

RESULTS

The accuracy of segmentation was SSAT:0.92, DSAT:0.88 and VAT:0.9. Average Hausdorff distance was less than 5 mm. Automated segmentation significantly correlated R² > 0.99 (p < 0.001) with ground truth for all 3-fat compartments. Predicted volumes were within ± 1.96SD from Bland-Altman analysis.

CONCLUSIONS

DL-based, comprehensive SSAT, DSAT, and VAT analysis tool showed high accuracy and reproducibility and provided a comprehensive fat compartment composition analysis and visualization in less than 10 s.

Association of measures of body fat with serum alpha-tocopherol and its metabolites in middle-aged individuals

BACKGROUND AND AIMS

The accumulation of fat increases the formation of lipid peroxides, which are partly scavenged by alpha-tocopherol (α-TOH). Here, we aimed to investigate the associations between different measures of (abdominal) fat and levels of urinary α-TOH metabolites in middle-aged individuals.

METHODS AND RESULTS

In this cross-sectional analysis in the Netherlands Epidemiology of Obesity study (N = 511, 53% women; mean [SD] age of 55 [6.1] years), serum α-TOH and α-TOH metabolites from 24-h urine were measured as alpha-tocopheronolactone hydroquinone (α-TLHQ, oxidized) and alpha-carboxymethyl-hydroxychroman (α-CEHC, enzymatically converted) using liquid-chromatography-tandem mass spectrometry. Body mass index and total body fat were measured, and abdominal subcutaneous and visceral adipose tissue (aSAT and VAT) were assessed using magnetic resonance imaging. Using multivariable-adjusted linear regression analyses, we analysed the associations of BMI, TBF, aSAT and VAT with levels of urinary α-TOH metabolites, adjusted for confounders. We observed no evidence for associations between body fat measures and serum α-TOH. Higher BMI and TBF were associated with lower urinary levels of TLHQ (0.95 [95%CI: 0.90, 1.00] and 0.94 [0.88, 1.01] times per SD, respectively) and with lower TLHQ relative to CEHC (0.93 [0.90, 0.98] and 0.93 [0.87, 0.98] times per SD, respectively). We observed similar associations for VAT (TLHQ: 0.94 [0.89, 0.99] times per SD), but not for aSAT.

CONCLUSIONS

Opposite to our research hypothesis, higher abdominal adiposity was moderately associated with lower levels of oxidized α-TOH metabolites, which might reflect lower vitamin E antioxidative activity in individuals with higher abdominal fat instead.

Differences in expression of genes related to steroidgenesis in abdominal subcutaneous adipose tissue of pregnant women with and without PCOS; a case control study

BACKGROUND

It was reported that steroid-related gene expressions in the adipose tissue (AT) of women differ between women affected with polycystic ovary syndrome (PCOS) and non-PCOS. Although association between PCOS in mother and offspring's health is a crucial issue, there are few studies focusing on AT of pregnant women suffering from PCOS. Our objectives were to determine the differences between mRNA expression levels of key steroid-converting enzymes in abdominal subcutaneous AT of pregnant women afflicted with PCOS and non-PCOS.

METHODS

Twelve pregnant women with PCOS (case) and thirty six non-PCOS pregnant women (control) (1:3 ratio; age- and BMI-matched) undergoing cesarean section were enrolled for the present study. Expressions of fifteen genes related to steriodogenesis in abdominal subcutaneous AT were investigated using quantitative real-time PCR.

RESULTS

No significant differences were detected with respect to age, BMI (prior pregnancy and at delivery day), gestational period and parity among pregnant women with PCOS and non-PCOS. Most of the sex steroid-converting genes except 17β-Hydroxysteroid dehydrogenases2 (17BHSD2), were highly expressed on the day of delivery in subcutaneous AT. Women with PCOS showed significantly higher mRNA levels of steroidgenic acute regulator (STAR; P < 0.001), cytochrome P450 monooxygenase (CYP11A1; P < 0.05), 17α-hydroxylase (CYP17A1; P < 0.05), and 11β-Hydroxysteroid dehydrogenase (11BHSD1 and 11BHSD2; P < 0.05). The expression of steroid 21-hydroxylase (CYP21) in non-PCOS was fourfold higher than those of women with PCOS (P < 0.001). There were no significant differences between relative expression of aromatase cytochrome P450 (CYP19A1), 3β-hydroxysteroid dehydrogenase (3BHSD1 and 3BHSD2), and 17BHSD family (1, 3, 5, 7, and 12) between the two groups.

CONCLUSION

The expression levels of genes related to sex steroids metabolism were similar to age-matched and BMI- matched pregnant non-PCOS and pregnant women with PCOS at delivery day. However, the alterations in gene expressions involved in glucocorticoids and mineralocorticoids metabolism were shown. It is necessary to point out that further studies regarding functional activity are required. More attention should be given to AT of pregnant women with PCOS that was previously ignored.

Predicting Cardiometabolic Risk From Visceral Abdominal Adiposity in Persons With Chronic Spinal Cord Injury

Persons with spinal cord injury (SCI) have increased adiposity that may predispose to cardiovascular disease compared to those who are able-bodied (AB). The purpose of this study was to determine the relationships between dual energy X-ray absorptiometry (DXA)-derived visceral adipose tissue (VAT) and biomarkers of lipid metabolism and insulin resistance in persons with chronic SCI. A prospective observational study in participants with chronic SCI and age- and gender-matched AB controls. The study was conducted at a Department of Veterans Affairs Medical Center and Private Rehabilitation Hospital. The quantification of DXA-derived VAT volume (VAT_vol) and blood-derived markers of lipid and carbohydrate metabolism were determined in 100 SCI and 51 AB men. The VAT_vol was acquired from a total body DXA scan and analyzed using iDXA enCore CoreScan software (GE Lunar). Blood samples were collected for the serum lipid profile and plasma and glucose concentrations, with the latter two values used to calculate a measure of insulin resistance. In the SCI and AB groups, VAT% was significantly correlated with most cardiometabolic biomarkers. The results of the binary logistic regression analysis revealed that participants who had a VAT_vol above the cutoff value of 1630 cm³ were 3.1-, 4.8-, 5.6-, 19.2-, and 16.7-times more likely to have high serum triglycerides (R²_N= 0.09, p = 0.014), low serum high density lipoprotein cholesterol (R²_N = 0.16, p < 0.001), HOMA2-IR (R²_N = 0.18, p < 0.001), metabolic syndrome (R²_N = 0.25, p < 0.001), and a 10-yr Framingham Risk Score ≥ 10% (R²_N = 0.16, p = 0.001), respectively, when compared to participants below this VAT_vol cutoff value. Our findings reveal that persons with chronic SCI have a higher VAT_vol than that of AB controls, and VAT_vol correlates directly with biomarkers of lipid and carbohydrate metabolism that are strong predictors of cardiometabolic disorders.

Adipose tissue radiodensity: A new prognostic biomarker in people with multiple myeloma

OBJECTIVES

Standard prognostic markers based on individual characteristics of individuals with multiple myeloma (MM) remain scarce. Body-composition features have often been associated with survival outcomes in different cancers. However, the association of adipose tissue radiodensity with MM prognosis has not yet, to our knowledge, been explored.

METHODS

Computed tomography at the third lumbar vertebra was used for body-composition analysis, including adipose tissue radiodensity, in 91 people with MM. Additionally, fludeoxyglucose F 18 (¹⁸F-FDG) positron emission tomography was used to assess adipose tissue ¹⁸F-FDG uptake. Proinflammatory cytokine and adipokine levels were measured.

RESULTS

Event-free survival and overall survival were both shorter in participants with high subcutaneous adipose tissue (SAT) radiodensity. Those in the highest SAT radiodensity tertile had an independently higher risk for both overall survival (hazard ratio, 4.55; 95% confidence interval, 1.26-16.44; P_trend = 0.036) and event-free survival (hazard ratio, 3.08; 95% confidence interval, 1.02-9.27; P_trend = 0.035). Importantly, higher SAT radiodensity was significantly correlated with increased ¹⁸F-FDG adipose tissue uptake and proinflammatory cytokine (tumor necrosis factor and interleukin-6) levels, and with decreased leptin levels.

CONCLUSIONS

SAT radiodensity may serve as a biomarker to predict host-related metabolic and proinflammatory milieu, which ultimately correlates with MM prognosis.

PPARγ-induced upregulation of subcutaneous fat adiponectin secretion, glyceroneogenesis and BCAA oxidation requires mTORC1 activity

The nutrient sensors peroxisome proliferator-activated receptor γ (PPARγ) and mechanistic target of rapamycin complex 1 (mTORC1) closely interact in the regulation of adipocyte lipid storage. The precise mechanisms underlying this interaction and whether this extends to other metabolic processes and the endocrine function of adipocytes are still unknown. We investigated herein the involvement of mTORC1 as a mediator of the actions of the PPARγ ligand rosiglitazone in subcutaneous inguinal white adipose tissue (iWAT) mass, endocrine function, lipidome, transcriptome and branched-chain amino acid (BCAA) metabolism. Mice bearing regulatory associated protein of mTOR (Raptor) deletion and therefore mTORC1 deficiency exclusively in adipocytes and littermate controls were fed a high-fat diet supplemented or not with the PPARγ agonist rosiglitazone (30 mg/kg/day) for 8 weeks and evaluated for iWAT mass, lipidome, transcriptome (Rnaseq), respiration and BCAA metabolism. Adipocyte mTORC1 deficiency not only impaired iWAT adiponectin transcription, synthesis and secretion, PEPCK mRNA levels, triacylglycerol synthesis and BCAA oxidation and mRNA levels of related proteins but also completely blocked the upregulation in these processes induced by pharmacological PPARγ activation with rosiglitazone. Mechanistically, adipocyte mTORC1 deficiency impairs PPARγ transcriptional activity by reducing PPARγ protein content, as well as by downregulating C/EBPα, a co-partner and facilitator of PPARγ. In conclusion, mTORC1 and PPARγ are essential partners involved in the regulation of subcutaneous adipose tissue adiponectin production and secretion and BCAA oxidative metabolism.

Transcriptomics analysis of differentially expressed genes in subcutaneous and perirenal adipose tissue of sheep as affected by their pre- and early postnatal malnutrition histories

BACKGROUND

Early life malnutrition is known to target adipose tissue with varying impact depending on timing of the insult. This study aimed to identify differentially expressed genes in subcutaneous (SUB) and perirenal (PER) adipose tissue of 2.5-years old sheep to elucidate the biology underlying differential impacts of late gestation versus early postnatal malnutrition on functional development of adipose tissues. Adipose tissues were obtained from 37 adult sheep born as twins to dams fed either NORM (fulfilling energy and protein requirements), LOW (50% of NORM) or HIGH (110% of protein and 150% of energy requirements) diets in the last 6-weeks of gestation. From day 3 to 6 months of age, lambs were fed high-carbohydrate-high-fat (HCHF) or moderate low-fat (CONV) diets, and thereafter the same moderate low-fat diet.

RESULTS

The gene expression profile of SUB in the adult sheep was not affected by the pre- or early postnatal nutrition history. In PER, 993 and 186 differentially expressed genes (DEGs) were identified in LOW versus HIGH and NORM, respectively, but no DEG was found between HIGH and NORM. DEGs identified in the mismatched pre- and postnatal nutrition groups LOW-HCHF (101) and HIGH-HCHF (192) were largely downregulated compared to NORM-CONV. Out of 831 DEGs, 595 and 236 were up- and downregulated in HCHF versus CONV, respectively. The functional enrichment analyses revealed that transmembrane (ion) transport activities, motor activities related to cytoskeletal and spermatozoa function (microtubules and the cytoskeletal motor protein, dynein), and responsiveness to the (micro) environmental extracellular conditions, including endocrine and nervous stimuli were enriched in the DEGs of LOW versus HIGH and NORM. We confirmed that mismatched pre- and postnatal feeding was associated with long-term programming of adipose tissue remodeling and immunity-related pathways. In agreement with phenotypic measurements, early postnatal HCHF feeding targeted pathways involved in kidney cell differentiation, and mismatched LOW-HCHF sheep had specific impairments in cholesterol metabolism pathways.

CONCLUSIONS

Both pre- and postnatal malnutrition differentially programmed (patho-) physiological pathways with implications for adipose functional development associated with metabolic dysfunctions, and PER was a major target.

Almond consumption decreases android fat mass percentage in adults with high android subcutaneous adiposity but does not change HbA1c in a randomised controlled trial

The purpose of this study was to determine if the mixed evidence of almond consumption on HbA1c stems from testing people with different body fat distributions (BFD) associated with different risks of glucose intolerance. A 6-month randomised controlled trial in 134 adults was conducted. Participants were randomly assigned to the almond (A) or control (C) group based on their BFD. Those in the almond group consumed 1·5 oz of almonds with their breakfast and as their afternoon snack daily. Those in the control group continued their habitual breakfast and afternoon snack routines. Body weight and composition were measured and blood samples were collected for determination of HbA1c, glycaemia and lipaemia at 0 and 6 months. Appetite ratings, energy intake and diet quality were collected at 0, 2, 4 and 6 months. Participants consuming almonds ingested 816 (sem 364) kJ/d more than participants in the control group (P = 0·03), but this did not result in any differences in body weight (A: –0·3 (sem 0·4), C: –0·4 (sem 0·4); P > 0·3). Participants in the almond, high android subcutaneous adipose tissue (SAT) group had a greater reduction in android fat mass percentage (A: –1·0 (sem 0·6), C: 1·1 (sem 0·6); P = 0·04), preserved android lean mass percentage (A: 0·9 (sem 0·6), C: –1 (sem 0·6); P = 0·04) and tended to decrease android visceral adipose tissue mass (A: –13 (sem 53) g, C: 127 (sem 53) g; P = 0·08) compared with those in the control, high SAT group. There were no differences in HbA1c between groups (A: 5·4 (sem 0·04), C: 5·5 (sem 0·04); P > 0·05). Thus, BFD may not explain the mixed evidence on almond consumption and HbA1c. Long-term almond consumption has limited ability to improve cardiometabolic health in those who are overweight and obese but otherwise healthy.

Adipose tissue fibrosis assessed by high resolution ex vivo MRI as a hallmark of tissue alteration in morbid obesity

To determine whether magnetic resonance imaging (MRI) when used in an optimal ex vivo setting can help detecting and quantifying the 3D fibrosis fraction in human subcutaneous adipose tissue (SAT) samples, as compared to histology. This prospective observational study was approved by our institutional review board 3D MRI acquisitions were performed at 4.0 T (Bruker) on XX human SAT samples (around 1 cm3) collected from biopsy in morbidly obese patients. Such acquisitions included saturation-recovery T1 mapping (spatial resolution: 200 µm, acquisition time: ~16 minutes) and DIXON imaging (spatial resolution: 200 µm, acquisition time: ~20 minutes). After MRI, histological quantification of fibrosis was performed using picrosirius staining. T1 maps were clustered based on a k-means algorithm allowing quantification of fibrosis within the adipose tissue and percentage of fibrosis over the entire sample volume was calculated. Fat maps were computed from DIXON in-phase and out-of-phase images. The 3D MRI fibrosis percentage within the SAT samples were comprised between 6% and 15%. Excellent correlations and levels of agreement were observed between single slice MRI and histology (r=0.9, P=0.08) and between 3D MRI and histology in terms fibrosis percentages within SAT samples (r=0.9, P=0.01). High Field ex vivo MRI was able to quantify fibrosis in human SAT samples with high agreement with histology and moreover to provide 3D SAT fibrosis quantification avoiding histological sampling errors.

Role of exercise on visceral adiposity after spinal cord injury: a cardiometabolic risk factor

PURPOSE

Visceral adipose tissue (VAT) is associated with cardiometabolic disease risk in able-bodied (AB) populations. However, the underlying mechanisms of VAT-induced disease risk are unknown in persons with spinal cord injury (SCI). Potential mechanisms of VAT-induced cardiometabolic dysfunction in persons with SCI include systemic inflammation, liver adiposity, mitochondrial dysfunction, and anabolic deficiency. Moreover, how exercise interventions impact these mechanisms associated with VAT-induced cardiometabolic dysfunction are still being explored.

METHODS

A search for relevant scientific literature about the effects of exercise on VAT and cardiometabolic health was conducted on the PubMed database. Literature from reference lists was also included when appropriate.

RESULTS

Both aerobic and resistance exercise training beneficially impact health and VAT mass via improving mitochondrial function, glucose effectiveness, and inflammatory signaling in SCI and AB populations. Specifically, aerobic exercise appears to also modulate cellular senescence in AB populations and animal models, while resistance exercise seems to augment anabolic signaling in persons with SCI.

CONCLUSIONS

The current evidence supports regular engagement in exercise to reduce VAT mass and the adverse effects on cardiometabolic health in persons with SCI. Future research is needed to further elucidate the precise mechanisms by which VAT negatively impacts health following SCI. This will likely facilitate the development of rehabilitation protocols that target VAT reduction in persons with SCI.

The 2020 ESPEN Arvid Wretlind lecture: Metabolic response in bariatric surgery - Mechanisms and clinical implications

BACKGROUND & AIMS

Owing to the "obesity-pandemic", an increasing number of individuals are in need of treatment for obesity and obesity-related disorders. For patients with severe disease, results with conventional treatment modalities such as diet regimens, physical activity, and pharmacologic agents most often lack satisfactory efficacy and/or sustainability. In contrast, bariatric surgery has been demonstrated to be associated with marked, long-term weight loss as well as resolution or improvement of co-morbid disease, in particular metabolic aberrations such as insulin resistance and type 2 diabetes. The underlying mechanisms for the effects of surgery-induced weight loss on such morbidity are incompletely understood.

METHODS

This article gives an updated overview of some aspects on the mechanisms involved in the improvement in metabolism in obese individuals submitted to surgery-induced weight loss. Patients undergoing Roux en-Y Gastric Bypass (RYGB) were studied before and at various times after the operation. Weight, body composition with determination of distribution of adipose tissue (DEXA), and insulin sensitivity (hyperinsulinemic clamp) was determined. In vitro; lipolytic activity and adipose morphology (fat cell size) was assessed.

RESULTS

Low calorie intake, rerouting of nutrients as well as loss of fat mass are all associated with improved insulin sensitivity after RYGB. In obese individuals, an increase in lipolytic activity in visceral adipose tissue might contribute to the association with cardiometabolic disease. However, selective reduction (omentectomy) seems not to improve insulin sensitivity or cardiometabolic risk. Adipose hyperplasia (many small cells) might be protective against metabolic abnormalities compared to hypertrophy (large cells). Preoperative fat cell size is related to improvement in insulin sensitivity after RYGB. Two years after weight loss, a change in adipose morphology to a more metabolically benign phenotype (remodeling) is seen, with a reduction of fat cell size which is correlated to the improvement in insulin sensitivity. Patients with weight regain 5 years after RYGB, still display a more benign metabolic profile compared to weight-matched controls.

CONCLUSIONS

Several factors contribute to the improvements in insulin sensitivity and cardiometabolic disease after surgery-induced weight loss, including low calorie intake rerouting of nutrients and loss of adipose tissue mass. Increased lipolytic activity in visceral adipose tissue as well as adipose hypertrophy relates to increased metabolic risk. RYGB-induced weight loss is associated with redistribution of adipose tissue as well as remodeling of fat cells to a more benign profile. Reduction of fat cell size might be a possible target to improve insulin sensitivity in patients with obesity in the future.