Bioconcentration of polycyclic aromatic hydrocarbons in the adipose tissue of women with pelvic endometriosis and idiopathic infertility: A case-control study.

PURPOSE: Polycyclic aromatic hydrocarbons (PAHs), present in air and food, generated during energy production and waste incineration, are known for health toxicity. PAHs may activate the aryl hydrocarbon receptor, which could in turn modify estrogen-dependent inflammatory pathways in endometriosis. The possible role of PAHs in the pathogenesis of endometriosis remains unclear. The study aimed to evaluate the potential link between exposure to PAHs and the occurrence of peritoneal and ovarian endometriosis. METHODS: A prospective case-control tertiary-center study included 46 women aged 22-45 undergoing laparoscopy due to pelvic endometriosis (n â€‹= â€‹32; arm 1) and idiopathic infertility (n â€‹= â€‹14; arm 2). A sample of the greater omentum was collected intraoperatively for detection of 16 standard PAHs by gas chromatography-isotope dilution mass spectrometry method. PAHs concentrations were compared in both study arms. The associations between PAHs concentrations and selected variables were investigated. RESULTS: There were no significant differences between both arms in terms of reference PAHs concentrations, nor correlations between PAHs concentrations and the stage of endometriosis. However, notable differences were observed in specific PAHs concentrations related to certain conditions. The concentrations of acenaphthene (p â€‹= â€‹0.016) and fluorene (p â€‹= â€‹0.013) were significantly lower in women with peritoneal adhesions, while the concentrations of benz[a]anthracene, benzo[k]fluoranthene and indeno[1,2,3-cd]pyrene [ng/g] were higher in cigarette smokers. CONCLUSIONS: The study showed no differences in exposure to PAHs between women with and without pelvic endometriosis. Determining the toxicity of PAHs in endometriosis requires further research.

Efficacy of injection of autologous adipose tissue in the treatment of patients with complex and recurrent fistula-in-ano of cryptoglandular origin.

BACKGROUND: Adipose tissue injections, a rich source of mesenchymal stem cells, have been successfully used to promote anal fistula healing. This study aimed to investigate the efficacy of adipose tissue injection in treating patients with complex and recurrent fistulas of cryptoglandular origin. METHODS: We conducted a prospective, single-center, open-label, non-randomized, interventional clinical trial from January 2020 to December 2022. We enrolled nine patients, who were evaluated after at least 12 months of follow-up. All patients had seton removal, fistula tract excision or curettage, and a mucosal flap if possible or, alternatively, an internal opening suture. We used a commercially available system to collect and process adipose tissue prior to injection. This system allowed the collection, microfragmentation, and filtration of tissue. RESULTS: Selected cases included six men and three women with a median age of 42 (range 31-55) years. All patients had an extended disease course period, ranging from 3 to 13 (mean 6.6) years, and a history of multiple previous surgeries, including two to eight interventions (a mean of 4.4 per case). All fistulas were high transsphincteric, four cases horseshoe and two cases with secondary suprasphincteric or peri-elevator tract fistulas. Six cases (66%) achieved complete fistula healing at a mean follow-up of 18 (range 12-36) months. Three cases (33.3%) experienced reduced secretion and decreased anal discomfort. CONCLUSIONS: In patients with complex and recurrent fistulas, such as the ones described, many from palliative treatments with setons, the adjuvant injection of adipose tissue might help achieve complete healing or improvement in a significant percentage of cases. CLINICALTRIALS: The study protocol was prospectively registered on ClinicalTrials.gov (NCT04750499).

Exploring the Link Between Metabolic Syndrome and Cellulite.

Metabolic syndrome (MetS) encompasses a cluster of metabolic abnormalities, including insulin resistance, hypertension, abdominal obesity, and dyslipidemia, increasing cardiovascular disease and type 2 diabetes risks. Cellulite, a cosmetic condition marked by dimpled skin, predominantly affects women and shares risk factors with MetS, such as obesity and hormonal imbalances. This review examines the potential link between MetS and cellulite, focusing on shared pathophysiological pathways and implications for clinical practice and future research. Common factors such as inflammation, hormonal changes, and adipose tissue dysfunction are explored. The review highlights the importance of longitudinal studies to track cellulite progression in MetS patients, biomarker identification for early detection, intervention trials to assess therapeutic efficacy, mechanistic studies to elucidate underlying pathways and the impact of comorbidities on cellulite development. Understanding these relationships can enhance prevention, diagnosis, and treatment strategies for both MetS and cellulite, addressing significant public health and cosmetic concerns.

A causal relationship between particulate matter 2.5 and obesity and its related indicators: a Mendelian randomization study of European ancestry.

Background: In recent years, the prevalence of obesity has continued to increase as a global health concern. Numerous epidemiological studies have confirmed the long-term effects of exposure to ambient air pollutant particulate matter 2.5 (PM2.5) on obesity, but their relationship remains ambiguous. Methods: Utilizing large-scale publicly available genome-wide association studies (GWAS), we conducted univariate and multivariate Mendelian randomization (MR) analyses to assess the causal effect of PM2.5 exposure on obesity and its related indicators. The primary outcome given for both univariate MR (UVMR) and multivariate MR (MVMR) is the estimation utilizing the inverse variance weighted (IVW) method. The weighted median, MR-Egger, and maximum likelihood techniques were employed for UVMR, while the MVMR-Lasso method was applied for MVMR in the supplementary analyses. In addition, we conducted a series of thorough sensitivity studies to determine the accuracy of our MR findings. Results: The UVMR analysis demonstrated a significant association between PM2.5 exposure and an increased risk of obesity, as indicated by the IVW model (odds ratio [OR]: 6.427; 95% confidence interval [CI]: 1.881-21.968; P FDR = 0.005). Additionally, PM2.5 concentrations were positively associated with fat distribution metrics, including visceral adipose tissue (VAT) (OR: 1.861; 95% CI: 1.244-2.776; P FDR = 0.004), particularly pancreatic fat (OR: 3.499; 95% CI: 2.092-5.855; PFDR =1.28E-05), and abdominal subcutaneous adipose tissue (ASAT) volume (OR: 1.773; 95% CI: 1.106-2.841; P FDR = 0.019). Furthermore, PM2.5 exposure correlated positively with markers of glucose and lipid metabolism, specifically triglycerides (TG) (OR: 19.959; 95% CI: 1.269-3.022; P FDR = 0.004) and glycated hemoglobin (HbA1c) (OR: 2.462; 95% CI: 1.34-4.649; P FDR = 0.007). Finally, a significant negative association was observed between PM2.5 concentrations and levels of the novel obesity-related biomarker fibroblast growth factor 21 (FGF-21) (OR: 0.148; 95% CI: 0.025-0.89; P FDR = 0.037). After adjusting for confounding factors, including external smoke exposure, physical activity, educational attainment (EA), participation in sports clubs or gym leisure activities, and Townsend deprivation index at recruitment (TDI), the MVMR analysis revealed that PM2.5 levels maintained significant associations with pancreatic fat, HbA1c, and FGF-21. Conclusion: Our MR study demonstrates conclusively that higher PM2.5 concentrations are associated with an increased risk of obesity-related indicators such as pancreatic fat content, HbA1c, and FGF-21. The potential mechanisms require additional investigation.

Prevalence of clinical characteristics of lipodystrophy in the US adult population in a healthcare claims database.

BACKGROUND: Lipodystrophy is characterized by progressive loss of adipose tissue and consequential metabolic abnormalities. With new treatments emerging for lipodystrophy, there is a growing need to understand the prevalence of specific comorbidities that may be commonly associated with lipodystrophy to contextualize the natural history of lipodystrophy without any disease modifying therapy. OBJECTIVE: To examine the risk of specific clinical characteristics in people living with lipodystrophy (LD) in 2018-2019 compared with the general US population, among the commercially insured US population. METHODS: A retrospective cohort study was conducted using the 2018-2019 Clinformatics® Data Mart database. An adult LD cohort (age ≥ 18 years) with at least ≥ 1 inpatient or ≥ 2 outpatient LD diagnoses was created. The LD cohort included non-HIV-associated LD (non-HIV-LD) and HIV-associated LD (HIV-LD) subgroups and compared against age- and sex-matched control groups with a 1:4 ratio from the general population with neither an LD or an HIV diagnosis using odds ratios (ORs) with 95% confidence intervals. RESULTS: We identified 546 individuals with non-HIV-LD (mean age, 60.3 ± 14.9 years; female, 67.6%) and 334 individuals with HIV-LD (mean age, 59.2 ± 8.3 years; female, 15.0%) in 2018-2019. Compared with the general population, individuals with non-HIV-LD had higher risks (odds ratio [95% confidence interval]) for hyperlipidemia (3.32 [2.71-4.09]), hypertension (3.58 [2.89-4.44]), diabetes mellitus (4.72 [3.85-5.79]), kidney disease (2.78 [2.19-3.53]), liver fibrosis or cirrhosis (4.06 [1.66-9.95]), cancer (2.20 [1.59-3.01]), and serious infections resulting in hospitalization (3.00 [2.19-4.10]). Compared with individuals with HIV, those with HIV-LD have higher odds of hypertension (1.47 [1.13-1.92]), hyperlipidemia (2.46 [1.86-3.28]), and diabetes (1.37 [1.04-1.79]). CONCLUSIONS: LD imposes a substantial burden on affected individuals due to a high prevalence of metabolic comorbidities and other complications as compared with the general non-LD population. Future longitudinal follow-up studies investigating the causality between LD and observed comorbidities are warranted.

Excessive accumulation of epicardial adipose tissue promotes microvascular obstruction formation after myocardial ischemia/reperfusion through modulating macrophages polarization.

BACKGROUND: Owing to its unique location and multifaceted metabolic functions, epicardial adipose tissue (EAT) is gradually emerging as a new metabolic target for coronary artery disease risk stratification. Microvascular obstruction (MVO) has been recognized as an independent risk factor for unfavorable prognosis in acute myocardial infarction patients. However, the concrete role of EAT in the pathogenesis of MVO formation in individuals with ST-segment elevation myocardial infarction (STEMI) remains unclear. The objective of the study is to evaluate the correlation between EAT accumulation and MVO formation measured by cardiac magnetic resonance (CMR) in STEMI patients and clarify the underlying mechanisms involved in this relationship. METHODS: Firstly, we utilized CMR technique to explore the association of EAT distribution and quantity with MVO formation in patients with STEMI. Then we utilized a mouse model with EAT depletion to explore how EAT affected MVO formation under the circumstances of myocardial ischemia/reperfusion (I/R) injury. We further investigated the immunomodulatory effect of EAT on macrophages through co-culture experiments. Finally, we searched for new therapeutic strategies targeting EAT to prevent MVO formation. RESULTS: The increase of left atrioventricular EAT mass index was independently associated with MVO formation. We also found that increased circulating levels of DPP4 and high DPP4 activity seemed to be associated with EAT increase. EAT accumulation acted as a pro-inflammatory mediator boosting the transition of macrophages towards inflammatory phenotype in myocardial I/R injury through secreting inflammatory EVs. Furthermore, our study declared the potential therapeutic effects of GLP-1 receptor agonist and GLP-1/GLP-2 receptor dual agonist for MVO prevention were at least partially ascribed to its impact on EAT modulation. CONCLUSIONS: Our work for the first time demonstrated that excessive accumulation of EAT promoted MVO formation by promoting the polarization state of cardiac macrophages towards an inflammatory phenotype. Furthermore, this study identified a very promising therapeutic strategy, GLP-1/GLP-2 receptor dual agonist, targeting EAT for MVO prevention following myocardial I/R injury.

Downregulation of adipose LPL by PAR2 contributes to the development of hypertriglyceridemia.

Lipoprotein lipase (LPL) hydrolyzes circulating triglycerides (TGs), releasing fatty acids (FA) and promoting lipid storage in white adipose tissue (WAT). However, the mechanisms regulating adipose LPL and its relationship with the development of hypertriglyceridemia are largely unknown. WAT from obese humans exhibited high PAR2 expression, which was inversely correlated with the LPL gene. Decreased LPL expression was also inversely correlated with elevated plasma TG levels, suggesting that adipose PAR2 might regulate hypertriglyceridemia by downregulating LPL. In mice, aging and high palmitic acid diet (PD) increased PAR2 expression in WAT, which was associated with a high level of macrophage migration inhibitory factor (MIF). MIF downregulated LPL expression and activity in adipocytes by binding with CXCR2/4 receptors and inhibiting Akt phosphorylation. In a MIF overexpression model, high-circulating MIF levels suppressed adipose LPL, and this suppression was associated with increased plasma TGs but not FA. Following PD feeding, adipose LPL expression and activity were significantly reduced, and this reduction was reversed in Par2-/- mice. Recombinant MIF infusion restored high plasma MIF levels in Par2-/- mice, and the levels decreased LPL and attenuated adipocyte lipid storage, leading to hypertriglyceridemia. These data collectively suggest that downregulation of adipose LPL by PAR2/MIF may contribute to the development of hypertriglyceridemia.

The role of interleukin-6 family cytokines in cancer cachexia.

Cachexia is a wasting syndrome that manifests in more than half of all cancer patients. Cancer-associated cachexia negatively influences the survival of patients and their quality of life. It is characterized by a rapid loss of adipose and skeletal muscle tissues, which is partly mediated by inflammatory cytokines. Here, we explored the crucial roles of interleukin-6 (IL-6) family cytokines, including IL-6, leukemia inhibitory factor, and oncostatin M, in the development of cancer cachexia. These cytokines have been shown to exacerbate cachexia by promoting the wasting of adipose and muscle tissues, activating mechanisms that enhance lipolysis and proteolysis. Overlapping effects of the IL-6 family cytokines depend on janus kinase/signal transducer and activator of transcription 3 signaling. We argue that the blockade of these cytokine pathways individually may fail due to redundancy and future therapeutic approaches should target common downstream elements to yield effective clinical outcomes.

Hibernoma in the renal sinus: A case mimicking malignancy.

Introduction: Hibernomas are benign tumors of brown adipose tissue. Hibernoma in the renal sinus is extremely rare. Herein, we present the third known case of renal hibernoma. Case presentation: A 71-year-old man reported to our department with a left kidney tumor with an average growth rate of 5 mm/year and a progressive contrast effect on computed tomography. It was diagnosed as a hibernoma following a laparoscopic radical nephrectomy. Conclusion: We encountered a rare case of a hibernoma in the renal sinus. Development of new and accurate diagnostic methods for hibernoma, without resorting to nephrectomy, is essential.

Outcomes of combined mitochondria and mesenchymal stem cells-derived exosome therapy in rat acute respiratory distress syndrome and sepsis.

BACKGROUND: The treatment of acute respiratory distress syndrome (ARDS) complicated by sepsis syndrome (SS) remains challenging. AIM: To investigate whether combined adipose-derived mesenchymal-stem-cells (ADMSCs)-derived exosome (EXAD) and exogenous mitochondria (mitoEx) protect the lung from ARDS complicated by SS. METHODS: In vitro study, including L2 cells treated with lipopolysaccharide (LPS) and in vivo study including male-adult-SD rats categorized into groups 1 (sham-operated-control), 2 (ARDS-SS), 3 (ARDS-SS + EXAD), 4 (ARDS-SS + mitoEx), and 5 (ARDS-SS + EXAD + mitoEx), were included in the present study. RESULTS: In vitro study showed an abundance of mitoEx found in recipient-L2 cells, resulting in significantly higher mitochondrial-cytochrome-C, adenosine triphosphate and relative mitochondrial DNA levels (P < 0.001). The protein levels of inflammation [interleukin (IL)-1ß/tumor necrosis factor (TNF)-α/nuclear factor-κB/toll-like receptor (TLR)-4/matrix-metalloproteinase (MMP)-9/oxidative-stress (NOX-1/NOX-2)/apoptosis (cleaved-caspase3/cleaved-poly (ADP-ribose) polymerase)] were significantly attenuated in lipopolysaccharide (LPS)-treated L2 cells with EXAD treatment than without EXAD treatment, whereas the protein expressions of cellular junctions [occluding/ß-catenin/zonula occludens (ZO)-1/E-cadherin] exhibited an opposite pattern of inflammation (all P < 0.001). Animals were euthanized by 72 h post-48 h-ARDS induction, and lung tissues were harvested. By 72 h, flow cytometric analysis of bronchoalveolar lavage fluid demonstrated that the levels of inflammatory cells (Ly6G+/CD14+/CD68+/CD11b/c+/myeloperoxidase+) and albumin were lowest in group 1, highest in group 2, and significantly higher in groups 3 and 4 than in group 5 (all P < 0.0001), whereas arterial oxygen-saturation (SaO2%) displayed an opposite pattern of albumin among the groups. Histopathological findings of lung injury/fibrosis area and inflammatory/DNA-damaged markers (CD68+/γ-H2AX) displayed an identical pattern of SaO2% among the groups (all P < 0.0001). The protein expressions of inflammatory (TLR-4/MMP-9/IL-1ß/TNF-α)/oxidative stress (NOX-1/NOX-2/p22phox/oxidized protein)/mitochondrial-damaged (cytosolic-cytochrome-C/dynamin-related protein 1)/autophagic (beclin-1/Atg-5/ratio of LC3B-II/LC3B-I) biomarkers exhibited a similar manner, whereas antioxidants [nuclear respiratory factor (Nrf)-1/Nrf-2]/cellular junctions (ZO-1/E-cadherin)/mitochondrial electron transport chain (complex I-V) exhibited an opposite manner of albumin among the groups (all P < 0.0001). CONCLUSION: Combined EXAD-mitoEx therapy was better than merely one for protecting the lung against ARDS-SS induced injury.

The Effect of Prenatal Docosahexaenoic Acid Supplementation on Offspring Fat Mass and Distribution at 24 Months Old.

Background: Excessive gestational weight gain (GWG) is related to increased offspring fat accrual, and increased fat mass (FM) is related to obesity development. Prenatal DHA supplementation has been linked to lower levels of offspring FM; however, conflicting data exist. Objectives: This study aimed to determine if there is a protective effect of prenatal DHA supplementation on offspring fat accrual and adipose tissue deposition at 24 mo in offspring born to females who gain excessive weight compared with nonexcessive weight during pregnancy. We also explored if the effect of DHA dose on FM differed by offspring sex. Methods: Infants born to females who participated in the Assessment of DHA on Reducing Early Preterm Birth randomized controlled trial (ADORE) were recruited. In ADORE, females were randomly assigned to either a high or low prenatal DHA supplement. Offspring body composition and adipose tissue distribution were measured using dual-energy x-ray absorptiometry (DXA). GWG was categorized as excessive or not excessive based on clinical guidelines. Results: For total FM, there was a significant main effect for the DHA dose (P = 0.03); however, the dose by GWG status was nonsignificant (P = 0.44). Therefore, a higher prenatal DHA dose was related to greater offspring FM (622.9 g greater) and unrelated to GWG status. When investigating a DHA dose by sex effect, a significant main effect for DHA dose (P = 0.01) was detected for central FM. However, no interaction was detected (P = 0.98), meaning that both boys and girls had greater central FM if their mother was assigned to the higher DHA dose. Conclusions: Greater prenatal DHA supplementation was associated with greater offspring FM and adipose tissue distribution at 24 mo. It will be important to understand if these effects persist into childhood.This trial was registered at clinicaltrials.gov as NCT03310983.

Morphological Changes of Peri-Coronary Adipose Tissue Together with Elevated NLR in Acute Myocardial Infarction Patients in-Hospital.

Background: Inflammation triggers atherosclerotic plaque rupture, leading to acute myocardial infarction (AMI). Following AMI, peri-coronary adipose tissue (PCAT) undergoes a transition from lipid-rich to hydrophilic characteristics due to vascular inflammation. This study investigates PCAT changes and neutrophil-to-lymphocyte ratio levels during AMI. Patients and Methods: 60 AMI patients undergoing coronary computed tomography angiography and angiography (Jan 2020-Jun 2022) were studied 60 age, gender, BMI-matched stable angina, and 60 non-coronary artery disease patients were included. Siemens VB20.0 measured PCAT-volume and fat attenuation index (FAI). Neutrophil-to-lymphocyte ratio levels were calculated by peripheral blood tests. Results: The PCAT volume and PCAT-FAI gradually increased across the control, stable angina, and AMI groups, with a corresponding gradual rise in NLR. NLR exhibited weak positive correlation with PCAT-FAI (r=0.35) and PCAT-volume (r=0.24). Multivariable logistic regression identified increased PCAT-volume, PCAT-FAI and neutrophil-to-lymphocyte ratio as possible independent AMI risk factors. No significant PCAT-volume difference was observed between infarct-related artery (IRA) and non-IRA for all three coronary arteries. Only PCAT-FAI around IRA-LAD was higher than non-IRA-LAD (-74.84±6.93 HU vs -79.04±8.68 HU). PCAT-FAI around culprit vessels in AMI was higher than corresponding lesion related vessel in SA. PCAT-volume around narrowed non-IRA in AMI was higher than that of corresponding LRV in SA. PCAT-FAI of narrowed non-IRA-LADs and non-IRA-LCXs in AMI were elevated compared to LADs (-78.46±8.56HU vs -83.13±8.34 HU) and LCXs (-73.83±10.63 HU vs -81.38±7.88 HU) of lesion related vessel in stable angina. Conclusion: We found an association between AMI and inflammation in the coronary perivascular adipose tissue and systemic inflammatory response.

Regional adiposity and insulin sensitivity - interactions with menopause and HIV in middle-aged Black African women.

OBJECTIVE: To explore depot-specific functional aspects of adipose tissue, examining the putative role for menopause and HIV status on insulin sensitivity (SI) and beta-cell function in Black South African women. METHODS: Women (n = 92) from the Middle-Aged Soweto Cohort, including premenopausal HIV-negative (n = 21); premenopausal women living with HIV (WLWH; n = 11); postmenopausal HIV-negative (n = 42); postmenopausal WLWH (n = 18) underwent the following tests: body composition (dual energy x-ray absorptiometry); fasting bloods for sex hormones, inflammation and adipokines; frequently sampled intravenous glucose tolerance test for SI and beta-cell function (disposition index, DI); abdominal (aSAT) and gluteal subcutaneous adipose tissue (gSAT) biopsies for cell size and mRNA expression of adipokines, inflammation, and estrogen receptors [ER]. RESULTS: Depot-specific associations between gene expression and insulin parameters did not differ by HIV or menopause status. Pooled analysis showed significant models for SI (P = 0.002) and DI (P = 0.003). Higher SI was associated with lower leptin and CD11c expression in aSAT and higher adiponectin in gSAT. Higher DI was associated with higher aSAT and gSAT expression of adiponectin, LPL, ERα, and PPARγ, and lower leptin in aSAT. WLWH had higher expression of adiponectin and lower expression of leptin in both aSAT (P = 0.002 and P = 0.005) and gSAT (P = 0.004 and P = 0.002), respectively, and a larger proportion of smaller cells in aSAT (P < 0.001). CONCLUSION: Insulin sensitivity and beta cell function were distinctively associated with aSAT and gSAT. While menopause did not influence these relationships, HIV had a significant effect on adipose tissue, characterised by variations in cell size distribution and transcript levels within the depots.

Neuregulin4-ErbB4 signalling pathway is driven by electroacupuncture stimulation to remodel brown adipose tissue innervation.

AIM: To show that electroacupuncture stimulation (ES) remodels sympathetic innervation in brown adipose tissue (BAT) via the bone morphogenic protein 8B (BMP8B)-neuregulin 4 (NRG4)-ErbB4 axis, with somatotopic dependence. MATERIALS AND METHODS: We established a high-fat diet (HFD) model with C57BL/6J mice to measure the thermogenesis and metabolism of BAT. In addition, the sympathetic nerve activity (SNA) was measured with the electrophysiological technique, and the immunostaining of c-Fos was used to detect the central nervous system sources of sympathetic outflows. Finally, the key role of the BMP8B-NRG4-ErbB4 axis was verified by peripheral specific antagonism of ErbB4. RESULTS: ES at the forelimb and abdomen regions significantly up-regulate SNA, whereas ES at the hindlimb region has a limited regulatory effect on SNA but still partially restores HFD-induced BAT dysfunction. Mechanistically, ES at the forelimb and abdomen regions driving catecholaminergic signals in brown adipocytes depends on neural activities projected from the ventromedial nucleus of the hypothalamus (VMH) to the spinal cord intermediolateral column (IML). Notably, the peripheral suppression of ErbB4 in BAT inhibits the thermogenesis and metabolic function of BAT, as well as significantly hindering the SNA activation and metabolic benefits induced by ES. CONCLUSION: These results suggest that ES appears to be an effective approach for remodeling sympathetic innervation in BAT, which is closely related to neuronal activity in the VMH and the NRG4-ErbB4 signaling pathway.

Trapped fat: Obesity pathogenesis as an intrinsic disorder in metabolic fuel partitioning.

Our understanding of the pathophysiology of obesity remains at best incomplete despite a century of research. During this time, two alternative perspectives have helped shape thinking about the etiology of the disorder. The currently prevailing view holds that excessive fat accumulation results because energy intake exceeds energy expenditure, with excessive food consumption being the primary cause of the imbalance. The other perspective attributes the initiating cause of obesity to intrinsic metabolic defects that shift fuel partitioning from pathways for mobilization and oxidation to those for synthesis and storage. The resulting reduction in fuel oxidation and trapping of energy in adipose tissue drives a compensatory increase in energy intake and, under some conditions, a decrease in expenditure. This theory of obesity pathogenesis has historically garnered relatively less attention despite its pedigree. Here, we present an updated comprehensive formulation of the fuel partitioning theory, focused on evidence gathered over the last 80 years from major animal models of obesity showing a redirection of fuel fluxes from oxidation to storage and accumulation of excess body fat with energy intake equal to or even less than that of lean animals. The aim is to inform current discussions about the etiology of obesity and by so doing, help lay new foundations for the design of more efficacious approaches to obesity research, treatment and prevention.

Skeletal muscle quantity and quality evaluation in heart failure: comparing thoracic versus abdominopelvic CT approaches.

Given the critical role of skeletal muscle in healthy aging, low muscle mass (myopenia) and quality (myosteatosis) can be used as predictors of poor functional and cardiometabolic outcomes. Myopenia is also a part of sarcopenia and malnutrition diagnostic criteria. However, there is limited evidence for using chest computed tomography (CT) to evaluate muscle health. We aimed to compare chest CT landmarks to the widely used L3 vertebra for single-slice skeletal muscle evaluation in patients with heart failure (HF). Patients admitted for acute decompensated HF between January 2017 and December 2018 were retrospectively analyzed. Body composition measurements were made on CT of the chest and abdomen/pelvis with or without contrast one month before discharge. Skeletal muscle index (SMI) and intermuscular adipose tissue percentage (IMAT%) were calculated at several thoracic levels (above the aortic arch, T8, and T12) and correlated to the widely used L3 level. A total of 200 patients were included, 89 (44.5%) female. The strongest correlation of thoracic SMI (for muscle quantity) and IMAT% (for muscle quality) with L3 was at the T12 level (r = 0.834, p < 0.001 and r = 0.757, p < 0.001, respectively). Cutoffs to identify low muscle mass for T12 SMI (derived from the lowest sex-stratified L3 SMI tertile) were 31.1 cm²/m² in men and 26.3 cm²/m² in women. SMI and IMAT% at T12 had excellent correlations with the widely used L3 level for muscle quantity and quality evaluation in patients with HF.

Increased secretion of adipocyte-derived extracellular vesicles is associated with adipose tissue inflammation and the mobilization of excess lipid in human obesity.

BACKGROUND: Obesity is a worldwide epidemic characterized by adipose tissue (AT) inflammation. AT is also a source of extracellular vesicles (EVs) that have recently been implicated in disorders related to metabolic syndrome. However, our understanding of mechanistic aspect of obesity's impact on EV secretion from human AT remains limited. METHODS: We investigated EVs from human Simpson Golabi Behmel Syndrome (SGBS) adipocytes, and from AT as well as plasma of subjects undergoing bariatric surgery. SGBS cells were treated with TNFα, palmitic acid, and eicosapentaenoic acid. Various analyses, including nanoparticle tracking analysis, electron microscopy, high-resolution confocal microscopy, and gas chromatography-mass spectrometry, were utilized to study EVs. Plasma EVs were analyzed with imaging flow cytometry. RESULTS: EVs from mature SGBS cells differed significantly in size and quantity compared to preadipocytes, disagreeing with previous findings in mouse adipocytes and indicating that adipogenesis promotes EV secretion in human adipocytes. Inflammatory stimuli also induced EV secretion, and altered EV fatty acid (FA) profiles more than those of cells, suggesting the role of EVs as rapid responders to metabolic shifts. Visceral AT (VAT) exhibited higher EV secretion compared to subcutaneous AT (SAT), with VAT EV counts positively correlating with plasma triacylglycerol (TAG) levels. Notably, the plasma EVs of subjects with obesity contained a higher number of adiponectin-positive EVs than those of lean subjects, further demonstrating higher AT EV secretion in obesity. Moreover, plasma EV counts of people with obesity positively correlated with body mass index and TNF expression in SAT, connecting increased EV secretion with AT expansion and inflammation. Finally, EVs from SGBS adipocytes and AT contained TAGs, and EV secretion increased despite signs of less active lipolytic pathways, indicating that AT EVs could be involved in the mobilization of excess lipids into circulation. CONCLUSIONS: We are the first to provide detailed FA profiles of human AT EVs. We report that AT EV secretion increases in human obesity, implicating their role in TAG transport and association with adverse metabolic parameters, thereby emphasizing their role in metabolic disorders. These findings promote our understanding of the roles that EVs play in human AT biology and metabolic disorders.

Preclinical Therapeutic Efficacy of Extracellular Vesicles Derived from Adipose-Derived Mesenchymal Stromal/Stem Cells in Diabetic Wounds: a Systematic Review and Meta-Analysis.

Extracellular vesicles isolated from adipose tissue-derived mesenchymal stromal/stem cells (ADSC-EVs) have demonstrated promising potential in wound healing treatment. To determine the therapeutic efficacy of ADSC-EVs for diabetic wounds in preclinical models, we performed a meta-analysis of available studies. PubMed and Embase were searched (to April 23, 2023). All full-text articles describing the therapeutic application of ADSC-EVs in diabetic wounds were included. Study outcomes were pooled using a random effects meta-analysis, including wound closure, angiogenesis, and collagen deposition. Other outcomes were only discussed descriptively. Seventy unique records were identified from our search; 20 full-text articles were included for qualitative analysis. Twelve studies were eligible for quantitative meta-analysis. The results showed that ADSC-EVs accelerated diabetic wound healing compared to controls with a large effect (standardized mean difference (SMD) 4.22, 95% confidence interval (CI) 3.07 to 5.36). The administration of ADSC-EVs also improved neovascularization (SMD 9.27, 95% CI 4.70 to 13.83) and collagen deposition (SMD 2.19, 95% CI 0.94 to 3.44), with a large effect. The risk of bias was unclear in all included studies. Conclusively, ADSC-EV is an effective treatment for diabetic wounds in preclinical trials, and it appears justified for transfer into the clinical field.

Intermuscular adipose tissue accumulation is associated with higher tissue sodium in healthy individuals.

BACKGROUND AND AIMS: High tissue sodium accumulation and intermuscular adipose tissue (IMAT) are associated with aging, type 2 diabetes, and chronic kidney disease. In this study, we aim to investigate whether high lower-extremity tissue sodium accumulation relates to IMAT quantity and whether systemic inflammatory mediators and adipocytokines contribute to such association. METHODS: Tissue sodium content and IMAT accumulation (percentage of IMAT area to muscle area) were measured in 83 healthy individuals using sodium imaging (23Na-MRI) and proton (1H-MRI) imaging of the calf. Insulin sensitivity was assessed by glucose disposal rate (GDR) measured with the hyperinsulinemic-euglycemic clamp. RESULTS: Median (interquartile range) muscle and skin sodium contents were 16.6 (14.9, 19.0) and 12.6 (10.9, 16.7) mmol/L, respectively. Median IMAT was 3.69 (2.80, 5.37) %. In models adjusted for age, sex, BMI, GDR, adiponectin, and high-sensitivity C-reactive protein, increasing tissue sodium content was significantly associated with higher IMAT quantity (p = 0.018 and 0.032 for muscle and skin tissue sodium, respectively). In subgroup analysis stratified by sex, skin sodium was significantly associated with IMAT only among men. In interaction analysis, the association between skin sodium and IMAT was greater with increasing levels of high-sensitivity C-reactive protein and interleukin-6 (p for interaction = 0.022 and 0.006, respectively). CONCLUSIONS: Leg muscle and skin sodium are associated with IMAT quantity among healthy individuals. The relationship between skin sodium and IMAT may be mediated by systemic inflammation.

SGLT2 inhibitor canagliflozin reduces visceral adipose tissue in db/db mice by modulating AMPK/KLF4 signaling and regulating mitochondrial dynamics to induce browning.

Obesity is characterized by excessive accumulation of adipose tissue (mainly visceral). The morphology and function of mitochondria are crucial for regulating adipose browning and weight loss. Research suggests that the SGLT2 inhibitor canagliflozin may induce weight loss through an unknown mechanism, particularly targeting visceral adipose tissue. While Krueppel-Like Factor 4 (KLF4) is known to be essential for energy metabolism and mitochondrial function, its specific impact on visceral adipose tissue remains unclear. We administered canagliflozin to db/db mice for 8 weeks, or exposed adipocytes to canagliflozin for 24 h. The expression levels of browning markers, mitochondrial dynamics, and KLF4 were assessed. Then we validated the function of KLF4 through overexpression in vivo and in vitro. Adenosine monophosphate-activated protein kinase (AMPK) agonists, inhibitors, and KLF4 si-RNA were employed to elucidate the relationship between AMPK and KLF4. The findings demonstrated that canagliflozin significantly decreased body weight in db/db mice and augmented cold-induced thermogenesis. Additionally, canagliflozin increased the expression of mitochondrial fusion-related factors while reducing the levels of fission markers in epididymal white adipose tissue. These consistent findings were mirrored in canagliflozin-treated adipocytes. Similarly, overexpression of KLF4 in both adipocytes and db/db mice yielded comparable results. In all, canagliflozin mitigates obesity in db/db mice by promoting the brown visceral adipocyte phenotype through enhanced mitochondrial fusion via AMPK/KLF4 signaling.