Metabolic Consequences Of Obesity Research Articles

Bioelectrical Impedance Analysis Detects Body Fat Changes After Surgical Subcutaneous Fat Removal.

Background: The risk and metabolic effects of obesity are determined by the distribution of fat throughout the body. It has been proposed that the distribution of abdominal fat is more closely related to the metabolic risks of obesity. High prevalence of overweight and obesity has thereby contributed to an increased uptake of surgical subcutaneous fat removal (SSFR) procedures. The goal of this study was to determine whether bioelectrical impedance analysis (Tanita system) can be used to detect the removal of excess abdominal subcutaneous fat tissue during SSFR when studying the metabolic effects of such procedures. Methods: Study population comprised patients who received body contouring procedures at the Hamad General Hospital's plastic surgery department between November 2020 and December 2022. To evaluate the factors of interest, subjects were prospectively followed up at two time points: within 1 week before the surgery and within 1-2 weeks thereafter. The following factors were measured: body weight, body fat percentage, body fat mass, body mass index (BMI), fat-free mass, estimated muscle mass, total body water, visceral fat score, and basal metabolic rate. Results: In total, 22 patients were included in the study. The two visits' medians for height, weight, BMI, fat percent (fat%), fat mass, visceral fat rating, and Doi's weighted average glucose (dwAG) were compared. Only in the case of Tanita fat% and fat mass, were the preoperative and postoperative medians significantly different. Furthermore, there was no association between these Tanita measures and dwAG or homeostatic model assessment (HOMA; insulin resistance [IR]) changes (before and after surgery). Tanita measures overestimated fat loss, as seen by the mountain plot and Bland-Altman plot agreement methods. Conclusions: Our findings indicated that the only two Tanita measures exhibited meaningful early associations with the amount of tissue excised which were fat mass and fat% differences. Although dwAG and HOMA-IR are not impacted immediately postsurgery, a trend was seen that suggested improvements in those parameters, even though the changes are not clinically significant.

Anti-Inflammatory Mechanisms of Curcumin and Its Metabolites in White Adipose Tissue and Cultured Adipocytes.

The plant-derived polyphenol curcumin alleviates the inflammatory and metabolic effects of obesity, in part, by reducing adipose tissue inflammation. We hypothesized that the benefits of curcumin supplementation on diet-induced obesity and systemic inflammation in mice occur through downregulation of white adipose tissue (WAT) inflammation. The hypothesis was tested in adipose tissue from high-fat diet-induced obese mice supplemented with or without curcumin and in 3T3-L1 adipocytes treated with or without curcumin. Male B6 mice were fed a high-fat diet (HFD, 45% kcal fat) with or without 0.4% (w/w) curcumin supplementation (HFC). Metabolic changes in these mice have been previously reported. Here, we determined the serum levels of the curcumin metabolites tetrahydrocurcumin (THC) and curcumin-O-glucuronide (COG) using mass spectrometry. Moreover, we determined interleukin 6 (IL-6) levels and proteomic changes in LPS-stimulated 3T3-L1 adipocytes treated with or without curcumin by using immunoassays and mass spectrometry, respectively, to gain further insight into any altered processes. We detected both curcumin metabolites, THC and COG, in serum samples from the curcumin-fed mice. Both curcumin and its metabolites reduced LPS-induced adipocyte IL-6 secretion and mRNA levels. Proteomic analyses indicated that curcumin upregulated EIF2 and mTOR signaling pathways. Overall, curcumin exerted anti-inflammatory effects in adipocytes, in part by reducing IL-6, and these effects may be linked to the upregulation of the mTOR signaling pathway, warranting additional mechanistic studies on the effects of curcumin and its metabolites on metabolic health.

Reduced Lipopolysaccharide-Binding Protein (LBP) Levels Are Associated with Non-Alcoholic Fatty Liver Disease (NAFLD) and Adipose Inflammation in Human Obesity.

Lipopolysaccharide (LPS) and its binding protein LBP have emerged as potential contributors to the progression from overweight/obesity to overt metabolic diseases and NAFLD. While LPS is known to activate hepatocyte inflammation, thus contributing toward NAFLD development, the role of LBP is more intricate, and recent data have shown that experimental reduction in hepatic LBP promotes NAFLD progression. In this cross-sectional investigation, we evaluated circulating LBP in relation to obesity, NAFLD, visceral adipose tissue (VAT) inflammation, and type 2 diabetes (T2D). We recruited 186 individuals (M/F: 81/105; age: 47 ± 10.4 years; BMI: 35.5 ± 8.6 kg/m2); a subgroup (n = 81) underwent bariatric surgery with intra-operative VAT and liver biopsies. LBP levels were higher in obese individuals than non-obese individuals but were inversely correlated with the parameters of glucose metabolism. Reduced LBP predicted T2D independent of age, sex, and BMI (p < 0.001). LBP levels decreased across more severe stages of hepatosteatosis and lobular inflammation, and were inversely associated with VAT inflammation signatures. In conclusion, LBP levels are increased in obese individuals and are associated with a more favorable metabolic profile and lower NAFLD/NASH prevalence. A possible explanation for these findings is that hepatic LBP production may be triggered by chronic caloric excess and facilitate LPS degradation in the liver, thus protecting these individuals from the metabolic consequences of obesity.

Metabolic obesity and the risk of knee osteoarthritis progression in elderly community residents: A 3-year longitudinal cohort study.

Metabolic syndrome is a major health problem worldwide associated with obesity, thus drawing attention to its relation to osteoarthritis (OA). However, it is still uncertain whether metabolic syndrome or body fat distribution is associated with knee OA. The aim of this longitudinal study was to elucidate the association between metabolic obesity and adverse structural changes of knee OA assessed by magnetic resonance imaging (MRI). Participants were recruited from the Hallym Aging Study cohort in Korea. Knee MRI scans, along with dual-energy X-ray absorptiometry, were assessed in 226 participants at baseline and after 3years. The structural progression in the tibiofemoral joint was evaluated using the semi-quantitative Whole-Organ MRI Score (WORMS) for cartilage morphology and bone marrow lesions (BML). Logistic regression with generalized estimating equation was performed for associations of metabolic risk factors with worsening of WORMS scores at the subregional level. In the medial compartment, fat mass in women was associated with cartilage loss, but the statistical significance disappeared after adjusting for body mass index. Metabolic syndrome and each of its components were not associated with cartilage loss or increase of BML. On the other hand, the interaction effects of metabolic syndrome on the association between obesity and knee OA progression were not significant. In this cohort, metabolic effects of obesity on knee cartilage damage and BML were not demonstrated. Further large-scale studies are required to prove the causal relationship between metabolic obesity and knee OA.

Obesity and Risk for First Ischemic Stroke Depends on Metabolic Syndrome: The HUNT Study.

Obesity is one of the most prevalent modifiable risk factors of ischemic stroke. However, it is still unclear whether obesity itself or the metabolic abnormalities due to obesity increase the risk of ischemic stroke. We therefore investigated the association between metabolic health, weight, and risk of ischemic stroke in a large prospective cohort study. In the Norwegian HUNT study (Trøndelag Health Study), we included 35 105 participants with complete information on metabolic risk factors and relevant covariates. Metabolically unhealthy state was defined as sex specific increased waist circumference in addition to 2 or more of the following criteria: hypertension, increased blood pressure, decreased high-density lipoprotein, triglycerides or glucose, or self-reported diagnosis of diabetes. We then applied Cox proportional hazard models to estimate the risk for ischemic stroke among overweight and obese metabolically healthy and unhealthy participants compared with metabolically healthy, normal weight participants. A total of 1161 ischemic stroke cases occurred after an average observation time of 11.9 years. In general, metabolically unhealthy participants were at increased risk of ischemic stroke (for obese participants: hazard ratio, 1.30 [95% CI, 1.09–1.56] compared with metabolically healthy participants with a normal body mass index). Hypertension appeared to be the most important metabolic risk factor. Metabolically healthy participants with overweight or obesity were at similar risk of ischemic stroke compared with normal weight participants (hazard ratio, 1.02 [95% CI, 0.81–1.28] for participants with obesity). Obesity and overweight even over an extended period of time seems to be benign about ischemic stroke, as long as it was not associated with metabolic abnormalities. Obesity was not an independent ischemic stroke risk factor in this cohort, and the risk depended more on the metabolic consequences of obesity.

Sex-Specific Differences in the Association Between Obesity and Depression in Large Epidemiological Studies: Findings From Dallas Heart Study and National Health and Nutrition Examination Survey

The inflammatory and metabolic effects of obesity, and how they contribute to pathophysiology of depression have gained recent attention. However, sex-specific differences in the association between obesity and depression remains poorly understood.

Metabolic consequences of obesity on the hypercoagulable state of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) women have a hypercoagulable state; however, whether this is intrinsically due to PCOS or, alternatively, a consequence of its metabolic complications is unclear. We determined plasma coagulation pathway protein levels in PCOS (n = 146) and control (n = 97) women recruited to a PCOS biobank. Circulating levels of a panel of 18 clotting pathway proteins were determined by Slow Off-rate Modified Aptamer-scan plasma protein measurement. Cohorts were age matched, though PCOS had elevated body mass index (p < 0.001), insulin (p < 0.001) and C-reactive protein (CRP) (p < 0.0001). Eight pro-coagulation proteins were elevated in PCOS: plasminogen activator inhibitor-1 (p < 0.0001), fibrinogen (p < 0.01), fibrinogen gamma chain (p < 0.0001), fibronectin (p < 0.01), von Willebrand factor (p < 0.05), D-dimer (p < 0.0001), P-selectin (p < 0.05), and plasma kallikrein (p < 0.001). However, two anticoagulant proteins, vitamin K-dependent protein-S (p < 0.0001) and heparin cofactor-II (p < 0.001) were elevated and prothrombin was decreased (p < 0.05). CRP, as a marker of inflammation, and insulin resistance (HOMA-IR) correlated with 11 and 6 of the clotting proteins, respectively (p < 0.05). When matched for BMI < 25 (16 PCOS, 53 controls) HOMA-IR remained elevated (p < 0.05) and heparin cofactor-II was increased (p < 0.05). In a multivariate analysis accounting for inflammation, insulin resistance and BMI, there was no correlation of PCOS with any of the coagulation proteins. The hypercoagulable state in PCOS is not intrinsic to the disease as it can be fully accounted for by BMI, inflammation and insulin resistance.

A214 BARIATRIC SURGERY PATIENTS WITH NON-ALCOHOLIC FATTY LIVER DISEASE HAVE DIFFERENT VISCERAL ADIPOSE TISSUE GENE EXPRESSION COMPARED TO THOSE WITH NORMAL LIVER

Abstract Background Non-alcoholic fatty liver disease (NAFLD) includes simple steatosis (SS) and nonalcoholic steatohepatitis (NASH). It affects 74–98% of individuals with morbid obesity undergoing bariatric surgery (BSX). Among several factors contributing to NAFLD pathogenesis, adipokines secreted by visceral adipose tissue (VAT) can play a role by regulating glucose/lipid metabolism and inflammation. Aims This study aims to determine if visceral adipose tissue adipokine and cytokine gene expression are associated with NAFLD (SS and NASH) at the time of BSX. Methods Patients were recruited from the Toronto Western Hospital Bariatric Clinic. Demographic data was recorded. The VAT and liver biopsies were collected at the time of bariatric surgery. VAT adipokines and other mediators were assessed by RT-PCR and included markers of thermogenic capacity, inflammation, fibrosis, adipokines, and others. Liver histology was assessed by a pathologist using the Brunt system and individuals were diagnosed as either SS, NASH, or having a healthy liver (HL). Blood samples were collected pre-BSX to measure liver and metabolic syndrome related parameters, including HOMA-IR, HbA1c, liver enzymes, and lipid profile. Anthropometry was also assessed. Groups were compared using Kruskal-Wallis test followed by Wilcoxon ranked sum, or chi-square and Fisher’s exact test as necessary. Data was considered to be statistically significant with a p-value less than 0.05. Results We are presenting data on 126 patients, 80.2% females with a median age of 49 and a body mass index (BMI) of 46.9. Fifty-seven patients had SS, 34 had NASH and 35 had a healthy liver (HL). BMI, age, and sex did not differ between the three groups. First, we found that those with NASH had significantly higher VAT expression of fibrosis (Loxl2), inflammation (CCL4 and TGFb1) and proliferation markers (E2F1) and significantly lower expression of adipokines (TNFa and resistin) compared to HL. Also, we found that SS had significantly higher fibrosis (Col3a1, Col6a1, Loxl2, CD9 and Acta2), inflammation (Nox2, TGFb1, IFNg and Clec10a), browning (PPARa, PPARg and Glut1) and proliferation (E2F1) marker expression compared to HL. Conclusions Results show that there is a significant difference in the expression pattern of VAT fibrotic and inflammatory markers between HL, SS and NASH patients. The observed increase of inflammatory markers in NAFLD is in line with prior research outlining the ability of inflammatory mediators from VAT to contribute to liver pathology via portal circulation. The relationship between VAT characteristics and NAFLD are important in understanding the widespread metabolic effects of obesity. Funding Agencies CIHRCanadian Liver foundation

Association Between Midlife Obesity and Its Metabolic Consequences, Cerebrovascular Disease, and Cognitive Decline.

Chronic obesity is associated with several complications, including cognitive impairment and dementia. However, we have only piecemeal knowledge of the mechanisms linking obesity to central nervous system damage. Among candidate mechanisms are other elements of obesity-associated metabolic syndrome, such as hypertension, dyslipidemia, and diabetes, but also systemic inflammation. While there have been several neuroimaging studies linking adiposity to changes in brain morphometry, a comprehensive investigation of the relationship has so far not been done. To identify links between adiposity and cognitive dysfunction. This observational cohort study (UK Biobank), with an 8-year follow-up, included more than 20 000 participants from the general community, with a mean age of 63 years. Only participants with data available on both baseline and follow-up timepoints were included. The main outcome measures were cognitive performance and mediator variables: hypertension, diabetes, systemic inflammation, dyslipidemia, gray matter measures, and cerebrovascular disease (volume of white matter hyperintensities on magnetic resonance imaging). Using structural equation modeling, we found that body mass index, waist-to-hip ratio, and body fat percentage were positively related to higher plasma C-reactive protein, dyslipidemia, hypertension, and diabetes. In turn, hypertension and diabetes were related to cerebrovascular disease. Finally, cerebrovascular disease was associated with lower cortical thickness and volume and higher subcortical volumes, but also cognitive deficits (largest significant pcorrected = 0.02). We show that adiposity is related to poor cognition, with metabolic consequences of obesity and cerebrovascular disease as potential mediators. The outcomes have clinical implications, supporting a role for the management of adiposity in the prevention of late-life dementia and cognitive decline.

The Interaction between Mitochondrial Oxidative Stress and Gut Microbiota in the Cardiometabolic Consequences in Diet-Induced Obese Rats.

Background: The objective of this study is to determine the role of mitochondrial oxidative stress in the dysbiosis associated with a high fat diet in rats. In addition, the impact of gut microbiota (GM) in the cardiometabolic consequences of diet-induced obesity in rats has been evaluated. Methods: Male Wistar rats were fed either a high fat diet (HFD) or a control (CT) one for 6 weeks. At the third week, one-half of the animals of each group were treated with the mitochondrial antioxidant MitoTempo (MT; 0.7 mgKg−1day−1 i.p). Results: Animals fed an HFD showed a lower microbiota evenness and diversity in comparison to CT rats. This dysbiosis is characterized by a decrease in Firmicutes/Bacteroidetes ratio and relevant changes at family and genera compared with the CT group. This was accompanied by a reduction in colonic mucin-secreting goblet cells. These changes were reversed by MT treatment. The abundance of certain genera could also be relevant in the metabolic consequences of obesity, as well as in the occurrence of cardiac fibrosis associated with obesity. Conclusions: These results support an interaction between GM and mitochondrial oxidative stress and its relation with development of cardiac fibrosis, suggesting new approaches in the management of obesity-related cardiometabolic consequences.

Aging Reduces Estradiol Protection Against Neural but Not Metabolic Effects of Obesity in Female 3xTg-AD Mice.

Vulnerability to Alzheimer’s disease (AD) is increased by several risk factors, including midlife obesity, female sex, and the depletion of estrogens in women as a consequence of menopause. Conversely, estrogen-based hormone therapies have been linked with protection from age-related increases in adiposity and dementia risk, although treatment efficacy appears to be affected by the age of initiation. Potential interactions between obesity, AD, aging, and estrogen treatment are likely to have significant impact on optimizing the use of hormone therapies in postmenopausal women. In the current study, we compared how treatment with the primary estrogen, 17β-estradiol (E2), affects levels of AD-like neuropathology, behavioral impairment, and other neural and systemic effects of preexisting diet-induced obesity in female 3xTg-AD mice. Importantly, experiments were conducted at chronological ages associated with both the early and late stages of reproductive senescence. We observed that E2 treatment was generally associated with significantly improved metabolic outcomes, including reductions in body weight, adiposity, and leptin, across both age groups. Conversely, neural benefits of E2 in obese mice, including decreased β-amyloid burden, improved behavioral performance, and reduced microglial activation, were observed only in the early aging group. These results are consistent with the perspective that neural benefits of estrogen-based therapies require initiation of treatment during early rather than later phases of reproductive aging. Further, the discordance between E2 protection against systemic versus neural effects of obesity across age groups suggests that pathways other than general metabolic function, perhaps including reduced microglial activation, contribute to the mechanism(s) of the observed E2 actions. These findings reinforce the potential systemic and neural benefits of estrogen therapies against obesity, while also highlighting the critical role of aging as a mediator of estrogens’ protective actions.

[Nutrition in Cancer: Effective in Prevention and Treatment?]

Nutritional effects on cancer occurrence and on treatment outcome in cancer patients may depend on food preferences and on the quantity of foods supplied. However, it has been difficult to reliably show beneficial effects of specific dietary concepts on cancer incidence. On the other hand, obesity as a result of chronic overfeeding has been linked firmly to an increased risk of a number of cancers as well as on cancer recurrence after treatment. Metabolic consequences of obesity and other components of the metabolic syndrome may be responsible for inducing and/or promoting cancer growth and should be antagonized by regular moderate physical activity in healthy subjects and in cancer survivors. During cancer treatment and in patients with advanced disease, inadequate food intake and physical inactivity may lead to malnutrition, while recurrent and chronic systemic inflammatory reactions induce chronic catabolism with a preferential loss of muscle and cell mass, condition referred to as cachexia.

The European medical information framework: A novel ecosystem for sharing healthcare data across Europe.

IntroductionThe European medical information framework (EMIF) was an Innovative Medicines Initiative project jointly supported by the European Union and the European Federation of Pharmaceutical Industries and Associations, that generated a common technology and governance framework to identify, assess and (re)use healthcare data, to facilitate real‐world data research. The objectives of EMIF included providing a unified platform to support a wide range of studies within two verification programmes—Alzheimer's disease (EMIF‐AD), and metabolic consequences of obesity (EMIF‐MET).MethodsThe EMIF platform was built around two main data‐types: electronic health record data and research cohort data, and the platform architecture composed of a set of tools designed to enable data discovery and characterisation. This included the EMIF catalogue, which allowed users to find relevant data sources, including the data‐types collected. Data harmonisation via a common data model were central to the project especially for population data sources. EMIF also developed an ethical code of practice to ensure data protection, patient confidentiality and compliance with the European Data Protection Directive, and GDPR.ResultsCurrently 18 population‐based disease agnostic and 60 cohort‐based Alzheimer's data partners from across 14 countries are contained within the catalogue, and this will continue to expand. The work conducted in EMIF‐AD and EMIF‐MET includes standardizing cohorts, summarising baseline characteristics of patients, developing diagnostic algorithms, epidemiological studies, identifying and validating novel biomarkers and selecting potential patient samples for pharmacological intervention.ConclusionsEMIF was designed to provide a sustainable model as demonstrated by the sustainability plans for EMIF‐AD. Although network‐wide studies using EMIF were not conducted during this project to evaluate its sustainability, learning from EMIF will be used in the follow‐on IMI‐2 project, European Health Data and Evidence Network (EHDEN). Furthermore, EMIF has facilitated collaborations between partners and continues to promote a wider adoption of principles, technology and architecture through some of its continued work.

Sex Differences in the Risk of Barrett’s Esophagus Associated With the Metabolic Effects of Obesity

The goal of this study was to determine if there is an association between the insulin-insulin-like growth factor axis, the metabolic syndrome (MetS), type 2 diabetes mellitus and risk of Barrett's esophagus (BE), and if these associations are modified by sex. BE is more common in males. Gastroesophageal reflux disease, the major risk factor for BE occurs at similar frequencies in both sexes, suggesting that sex-related factors such as the metabolic effects of abdominal obesity may be important in the causation of BE. A structured interview, anthropometric measures, and fasting blood were collected within a population-based case-control study. We recruited 227 BE cases (70% male) and 241 population controls, frequency matched by age and sex. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) for association with BE using multivariable logistic regression models. Hyperinsulinemia (highest vs. lowest tertile, OR=1.9; 95% CI: 1.2-3.1), Homeostatic Model Assessment of Insulin Resistance (OR=1.9; 95% CI: 1.2-3.1) and the MetS (OR=1.8; 95% CI: 1.2-2.6) were independently associated with an increased risk of BE. With each additional MetS criterion, there was a 20% increased risk of BE (OR=1.2; 95% CI: 1.0-1.4). When stratified by sex, these associations were found in males but not females. We found no association with serum measures of insulin-like growth factors or interleukin-6 and risk of BE. Hyperinsulinemia, insulin resistance, and the MetS are associated with the risk of BE in males but not females, suggesting these factors may contribute to the higher prevalence of BE in males.

Dysmetabolic markers predict outcomes in autosomal dominant polycystic kidney disease.

Overweight and obesity were recently associated with a poor prognosis in patients with autosomal dominant polycystic kidney disease (ADPKD). Whether the metabolic consequences of obesity as defined by the metabolic syndrome (MS) are also linked with disease progression remains untested. Eligible ADPKD patients with different stages of CKD (n = 105) and 105 non-diabetic controls matched for CKD stage were enrolled in the study. Groups were evaluated at baseline for presence of MS, blood markers of metabolism, homeostasis model assessment of insulin resistance (HOMA-IR) score, and biochemical markers of inflammation (hs-CRP, IL-1β, IL-6, TNF-α and PON-1). MS was defined according to the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III). Patients were followed for 12months and progression defined as a decrease in baseline eGFR > 10%. MS and hypertension were more prevalent amongst ADPKD patients than in the control group. Meanwhile, markers of inflammation such as hs-CRP (3.63 [3.45-5.17] vs. 4.2 [3.45-8.99] mg/dL; p = 0.014), IL-6 (21.65 [14.1-27.49] vs. 24.9 [16.23-39.4] pg/mL; p = 0.004) and IL-1β (21.33 [15.8-26.4] vs. 26.78 [18.22-35] pg/mL; p < 0.001) levels were all more elevated in ADPKD patients than in non-diabetic CKD subjects. In multivariate analysis having a truncating PKD1 mutation predicted (OR 1.25 [1.09-1.43]; p = 0.002) fulfilling the MS criteria. Finally, ADPKD patients fulfilling MS criteria had a significantly more rapid progression during 12months of follow-up than did those that did not (OR 3.28 [1.09-9.87]; p = 0.035). Our data supports the notion that dysmetabolisms part of the ADPKD phenotype and associated with a poor outcome, especially in patients with a truncating PKD1 mutation.

Genetic Architecture of Human Obesity Traits in the Rhesus Macaque

Objective:While the metabolic consequences of obesity have been studied extensively in the rhesus macaque, corollary genetic studies of obesity are non-existent. Here, we assess genetic contributions to spontaneous adiposity in this species.Methods:We assessed phenotypic variation by age-class and sex for body mass index, waist-to-height ratio, waist-to-thigh ratio, and waist circumference in 583 macaques. We estimated total and sex-specific heritability for all traits, including waist-to-thigh ratio adjusted for BMI, as well as genotypic and phenotypic correlations. We also assessed functional genetic variation at BDNF, FTO, LEP, LEPR, MC4R, PCSK1, POMC, and SIM1 in 4 animals with extreme spontaneous adiposity.Results:Trait heritability in the combined sample was low-to-moderate (0.14–0.32), while sex-specific heritability was more substantial (0.20–0.67). Heritability was greater in females for all traits except BMI. All traits were robustly correlated, with genetic correlations of 0.63–0.93 indicating substantial pleiotropy. We discovered likely functional variants in the 4 macaques at all 8 human obesity genes, including 6 missense mutations in BDNF, FTO, LEP, LEPR, and PCSK1, and notably, 1 nonsense mutation in LEPR.Conclusions:We find a moderate polygenic contribution to adiposity in rhesus macaques, and mutations with potentially larger effects in multiple genes that influence obesity in humans.

Calcium-sensing receptor activates the NLRP3 inflammasome in LS14 preadipocytes mediated by ERK1/2 signaling.

The study of the mechanisms that trigger inflammation in adipose tissue is key to understanding and preventing the cardiometabolic consequences of obesity. We have proposed a model where activation of the G protein-coupled calcium sensing receptor (CaSR) leads to inflammation and dysfunction in adipose cells. Upon activation, CaSR can mediate the expression and secretion of proinflammatory factors in human preadipocytes, adipocytes, and adipose tissue explants. One possible pathway involved in CaSR-induced inflammation is the activation of the NLR family, pyrin domain-containing 3 (NLRP3) inflammasome, that promotes maturation and secretion of interleukin (IL)-1β. The present work aimed to study whether CaSR mediates the activation of NLRP3 inflammasome in the human adipose cell model LS14. We assessed NLRP3 inflammasome priming and assembly after cinacalcet-induced CaSR activation and evaluated if this activation is mediated by downstream ERK1/2 signaling in LS14 preadipocytes. Exposure to 2 μM cinacalcet elevated mRNA expression of NLRP3, CASP-1, and IL-1β, as well as an increase in pro-IL-1β protein. In addition, CaSR activation triggered NLRP3 inflammasome assembly, as evidenced by a 25% increase in caspase-1 activity and 63% IL-1β secretion. CaSR silencing (siRNA) abolished the effect. Upstream ERK pathway inhibition decreased cinacalcet-dependent activation of NLRP3 inflammasome. We propose CaSR-dependent NLRP3 inflammasome activation in preadipocytes through ERK signaling as a novel mechanism for the development of adipose dysfunction, that may favor the cardiovascular and metabolic consequences of obesity. To the best of our knowledge, this is the first report linking the inflammatory effect of CaSR to NLRP3 inflammasome induction in adipose cells.

Inhibition of galectin-3 ameliorates the consequences of cardiac lipotoxicity in a rat model of diet-induced obesity.

ABSTRACTObesity is accompanied by metabolic alterations characterized by insulin resistance and cardiac lipotoxicity. Galectin-3 (Gal-3) induces cardiac inflammation and fibrosis in the context of obesity; however, its role in the metabolic consequences of obesity is not totally established. We have investigated the potential role of Gal-3 in the cardiac metabolic disturbances associated with obesity. In addition, we have explored whether this participation is, at least partially, acting on mitochondrial damage. Gal-3 inhibition in rats that were fed a high-fat diet (HFD) for 6 weeks with modified citrus pectin (MCP; 100 mg/kg/day) attenuated the increase in cardiac levels of total triglyceride (TG). MCP treatment also prevented the increase in cardiac protein levels of carnitine palmitoyl transferase IA, mitofusin 1, and mitochondrial complexes I and II, reactive oxygen species accumulation and decrease in those of complex V but did not affect the reduction in 18F-fluorodeoxyglucose uptake observed in HFD rats. The exposure of cardiac myoblasts (H9c2) to palmitic acid increased the rate of respiration, mainly due to an increase in the proton leak, glycolysis, oxidative stress, β-oxidation and reduced mitochondrial membrane potential. Inhibition of Gal-3 activity was unable to affect these changes. Our findings indicate that Gal-3 inhibition attenuates some of the consequences of cardiac lipotoxicity induced by a HFD since it reduced TG and lysophosphatidyl choline (LPC) levels. These reductions were accompanied by amelioration of the mitochondrial damage observed in HFD rats, although no improvement was observed regarding insulin resistance. These findings increase the interest for Gal-3 as a potential new target for therapeutic intervention to prevent obesity-associated cardiac lipotoxicity and subsequent mitochondrial dysfunction.

The genetics of obesity - Pathogenetic, clinical and diagnostic aspects

Due to its prevalence and its health-related, economic and social consequences, childhood and adult obesity is a complex, medical and civilizational problem, which has been on the increase in the last decade. The results of multi-center investigations reveal that genetic factors play an essential role in the etiopathogenesis of obesity, particularly in the case of extreme cases with very early onset. The Body Mass Index (BMI) is one of the most frequently used indicators of obesity and shows a strong genetic component with a 40-70% degree of heritability. The three types of genetically conditioned obesity are: (1) isolated (nonsyndromic) monogenic obesity, (2) syndromic monogenic obesity associated with dysmorphic features and/or congenital defects, caused by mutations in specific gene(s), (3) chromosomal aberrations, including submicroscopic changes. The most prevalent common (complex) obesity is linked to the presence of various changes in different genomic loci, which are subject to interactions and modifications by environmental (ethnic, dietary, lifestyle, bacterial flora, oxidative stress), as well as epigenetic (i.e., associated with DNA methylation, histone modification) and epistatic (gene-gene interaction) factors. Recent investigations using the modern methods of genome-wide association studies (GWAS), bioinformatics and proteomics, have made it possible to elucidate 8 key genes among the 97 genes most likely to play significant roles in the metabolic effects of obesity. The results of investigations on the pathogenesis of complex obesity do not as yet clarify the potential pathogenic significance of these genomic changes in humans. This article discusses the neuro-endocrinological regulation of the sensation of hunger and thirst, the clinical consequences of mutations in genes associated with the melanocortin pathway, and the features of the most common obesity syndromes, including syndromes conditioned by genomic imprinting. A diagnostic algorithm for cases of suspected syndromic obesity is proposed.

[Nutrition in Cancer: Effective in Prevention and Treatment?]

Nutritional effects on cancer occurrence and on treatment outcome in cancer patients may depend on food preferences and on the quantity of foods supplied. However, it has been difficult to reliably show beneficial effects of specific dietary concepts on cancer incidence. On the other hand, obesity as aresult of chronic overfeeding has been linked firmly to an increased risk of a number of cancers as well as on cancer recurrence after treatment. Metabolic consequences of obesity and other components of the metabolic syndrome may be responsible for inducing and/or promoting cancer growth and should be antagonized by regular moderate physical activity in healthy subjects and in cancer survivors. During cancer treatment and in patients with advanced disease, inadequate food intake and physical inactivity may lead to malnutrition, while recurrent and chronic systemic inflammatory reactions induce chronic catabolism with a preferential loss of muscle and cell mass, condition referred to as cachexia.