Cultivated Enterococcus faecium B6 from children with obesity promotes nonalcoholic fatty liver disease by the bioactive metabolite tyramine.

Gut microbiota plays an essential role in nonalcoholic fatty liver disease (NAFLD). However, the contribution of individual bacterial strains and their metabolites to childhood NAFLD pathogenesis remains poorly understood. Herein, the critical bacteria in children with obesity accompanied by NAFLD were identified by microbiome analysis. Bacteria abundant in the NAFLD group were systematically assessed for their lipogenic effects. The underlying mechanisms and microbial-derived metabolites in NAFLD pathogenesis were investigated using multi-omics and LC-MS/MS analysis. The roles of the crucial metabolite in NAFLD were validated in vitro and in vivo as well as in an additional cohort. The results showed that Enterococcus spp. was enriched in children with obesity and NAFLD. The patient-derived Enterococcus faecium B6 (E. faecium B6) significantly contributed to NAFLD symptoms in mice. E. faecium B6 produced a crucial bioactive metabolite, tyramine, which probably activated PPAR-γ, leading to lipid accumulation, inflammation, and fibrosis in the liver. Moreover, these findings were successfully validated in an additional cohort. This pioneering study elucidated the important functions of cultivated E. faecium B6 and its bioactive metabolite (tyramine) in exacerbating NAFLD. These findings advance the comprehensive understanding of NAFLD pathogenesis and provide new insights for the development of microbe/metabolite-based therapeutic strategies.

Inulin supplementation exhibits increased muscle mass via gut-muscle axis in children with obesity: double evidence from clinical and in vitro studies.

Gut microbiota manipulation may reverse metabolic abnormalities in obesity. Our previous studies demonstrated that inulin supplementation significantly promoted Bifidobacterium and fat-free mass in obese children. We aimed to study gut-muscle axis from inulin supplementation in these children. In clinical phase, the plasma samples from 46 participants aged 7-15 years, were analyzed for muscle biomarkers before and after 6-month inulin supplementation. In parallel, the plausible mechanism of muscle production via gut-muscle axis was examined using macrophage cell line. Bifidobacterium was cultured in semi-refined medium with inulin used in the clinical phase. Cell-free supernatant was collected and used in lipopolysaccharide (LPS)-induced macrophage cell line to determine inflammatory and anti-inflammatory gene expression. In clinical phase, IL-15 and creatinine/cystatin C ratio significantly increased from baseline to the 6th month. In vitro study showed that metabolites derived from Bifidobacterium capable of utilizing inulin contained the abundance of SCFAs. In the presence of LPS, treatment from Bifidobacterium + inulin downregulated TNF-α, IL-6, IL-1ß, and iNOS, but upregulated FIZZ-1 and TGF-ß expression. Inulin supplementation promoted the muscle biomarkers in agreement with fat-free mass gain, elucidating by Bifidobacterium metabolites derived from inulin digestion showed in vitro anti-inflammatory activity and decreased systemic pro-inflammation, thus promoting muscle production via gut-muscle axis response.Clinical Trial Registry number: NCT03968003.

Baseline higher hair cortisol moderated some effects in a healthy lifestyle intervention.

Children and families from socioeconomically marginalized background experience high levels of stress, especially persistent chronic stress, due to unstable housing, employment, and food insecurity. Although consistent evidence supports a stress-obesity connection, little research has examined the potential moderation role of stress in childhood obesity interventions. Therefore, this study aimed to explore how chronic stress (hair cortisol) moderated the effects of a healthy lifestyle intervention on improving behavioral and anthropometric outcomes among 95 socioeconomically marginalized parent-child dyads. Data were collected in a cluster randomized controlled trial with 10 Head Start childcare centers being randomized into intervention and control. The child sample (3-5 years old) included 57.9 % female, 12.6 % Hispanic, and 40.0 % Black. For the parents, 91.6 % were female, 8.4 % were Hispanic, 36.8 % were Black, and 56.8 % were single. Parent baseline hair cortisol significantly moderated the intervention effects on child fruit intake (B = -1.56, p = .030) and parent nutrition self-efficacy (B = 1.49, p = .027). Specifically, higher parent hair cortisol lowered the increases in child fruit intake but improved the increases in parent nutrition self-efficacy in the intervention group compared to control group. Child higher baseline hair cortisol was significantly associated with the decreases in child fruit intake (B = -0.60, p = .025). Child baseline hair cortisol significantly moderated the intervention effects on parent physical activity (PA) self-efficacy (B = -1.04, p = .033) and PA parental support (B = -0.50, p = .016), with higher child hair cortisol decreasing the improvement on these two outcomes in the intervention group compared to control group. Results from this study shed lights on the moderation role of chronic stress on impacting healthy lifestyle intervention effects. Although needing further investigation, the adverse effects of chronic stress on intervention outcomes should be considered when developing healthy lifestyle interventions for preschoolers and their families.

Prediction of resting energy expenditure for adolescents with severe obesity: A multi-centre analysis.

BACKGROUND AND OBJECTIVES: Resting energy expenditure (REE) assessments can help inform clinical treatment decisions in adolescents with elevated body mass index (BMI), but current equations are suboptimal for severe obesity. We developed a predictive REE equation for youth with severe obesity and obesity-related comorbidities and compared results to previously published predictive equations. METHODS: Data from indirect calorimetry, clinical measures, and body composition per Dual x-ray absorptiometry (DXA) were collected from five sites. Data were randomly divided into development (N = 438) and validation (N = 118) cohorts. A predictive equation was developed using Elastic Net regression, using sex, race, ethnicity, weight, height, BMI percent of the 95th%ile (BMIp95), waist circumference, hip circumference, waist/hip ratio, age, Tanner stage, fat and fat-free mass. This equation was verified in the validation cohort and compared with 11 prior equations. RESULTS: Data from the total cohort (n = 556, age 15 ± 1.7 years, 77% female, BMIp95 3.3 ± 0.94) were utilized. The best fit equation was REE = -2048 + 18.17 × (Height in cm) - 2.57 × (Weight in kg) + 7.88 × (BMIp95) + 189 × (1 = male, 0 = female), R2 = 0.466, and mean bias of 23 kcal/day. CONCLUSION: This new equation provides an updated REE prediction that accounts for severe obesity and metabolic complications frequently observed in contemporary youth.

Exposure to 4,4'-DDE in visceral adipose tissue and weight loss in adolescents from the Teen-LABS cohort.

OBJECTIVE: Dichlorodiphenyldichloroethylene (DDE), an obesogen accumulating in adipose tissue, is released into circulation with weight loss, although its impact is underexplored among adolescents. We tested the association using an integrative translational approach of epidemiological analysis among adolescents with obesity and in vitro measures exploring the impact of DDE on adipogenesis via preadipocytes. METHODS: We included 63 participants from the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) cohort. We assessed 4,4'-DDE in visceral adipose tissue at surgery and BMI and waist circumference at surgery and 0.5, 1, 3, and 5 years after. We conducted longitudinal analysis to estimate the interaction on weight loss between DDE and time since surgery. In vitro analysis quantified adipogenic differentiation in commercial human preadipocytes exposed to 4,4'-DDE via fluorescent staining and imaging. RESULTS: A dose-response relationship was observed, with the low-exposure group having a greater reduction in BMI during the first year compared to higher-exposure groups and showing smaller regains compared to higher-exposure groups after the first year. In vitro analysis of preadipocytes treated with 4,4'-DDE during adipogenic differentiation for 12 days showed a concentration-dependent increase in lipid accumulation. CONCLUSIONS: DDE could contribute to weight trajectory among adolescents undergoing bariatric surgery, potentially mediated via promoted adipogenesis in preadipocytes.

Decreased vitamin D bio-availability with altered DNA methylation of its metabolism genes in association with the metabolic disorders among the school-aged children with degree I, II, and III obesity.

Obesity is strongly associated with disturbances of vitamin D (VD) metabolites in the animal models. However, the related epidemiological evidence is still controversial, especially the different degrees of obesity children. Hence, in this present representative case-control study, 106 obesity school-age children aged 7-12 years were included and divided into different subgroups as degree I (the age- and sex-specific BMI≥95th percentile, n=45), II (BMI ≥120% percentile, n=34) and III (BMI ≥140% percentile, n=27) obesity groups across the ranges of body mass index (BMI). While the age- and sex-matched subjects without obesity were as the control group. Notably, it was significantly different of body composition, anthropological and clinical characteristics among the above four subgroups with the dose-response relationships (P<.05). Moreover, comparing with the control group, the serum VD concentrations were higher, VD metabolites like 25(OH)D, 25(OH)D3 and 1,25(OH)2D, and related hydroxylases as CYP27A1, CYP2R1 and CYP27B1 were lower in the degree I, II, and III obesity subgroups (P<.05), which were more disorder with the anthropological and clinical characteristics as the obesity was worsen in a BMI-independent manner (P<.05). However, there was a significant increase of CYP27B1 in the degree III obesity group than those in the degree I and II obesity subgroups. Furthermore, the methylation patterns on the genome-wide (Methylation/Hydroxymethylation) and VD metabolism genes (CYP27A1, CYP2R1 and CYP27B1) were negatively correlated with the worse obesity and their related expressions (P<.05). In summary, these results indicated that obesity could affect the homeostasis of VD metabolism related genes such as CYP27A1, CYP2R1, CYP27B1 and etc through abnormal DNA methylation, resulting in the disorders of VD related metabolites to decrease VD bio-availability with the BMI-independent manner. In turn, the lower levels of VD metabolites would affect the liver function to exacerbate the progression of obesity, as the Degree II and III obesity subgroups.

Integrative metabolomics highlights gut microbiota metabolites as novel NAFLD-related candidate biomarkers in children.

Altered gut microbiota and metabolites are important for non-alcoholic fatty liver disease (NAFLD) in children. We aimed to comprehensively examine the effects of gut metabolites on NAFLD progression. We performed integrative metabolomics (untargeted discovery and targeted validation) analysis of non-alcoholic fatty liver (NAFL), non-alcoholic steatohepatitis (NASH), and obesity in children. Fecal samples were collected from 75 subjects in the discovery cohort (25 NAFL, 25 NASH, and 25 obese control children) and 145 subjects in an independent validation cohort (53 NAFL, 39 NASH, and 53 obese control children). Among 2,491 metabolites, untargeted metabolomics revealed a complete NAFLD metabolic map containing 318 increased and 123 decreased metabolites. Then, machine learning selected 65 important metabolites that can distinguish the severity of the NAFLD. Furthermore, precision-targeted metabolomics selected 5 novel gut metabolites from 20 typical metabolites. The functionality of candidate metabolites was validated in hepatocyte cell lines. In the end, this study annotated two novel elevated pathogenic metabolites (dodecanoic acid and creatinine) and a relationship between depleted protective gut microbiota (Butyricicoccus and Alistipes), increased inflammation (IL-1ß), lipid metabolism (TG), and liver function (ALT and AST). This study demonstrates the role of novel gut metabolites (dodecanoic acid and creatinine), as the fatty acid metabolism regulator contributing to NAFLD development through its influence on inflammation and liver function. IMPORTANCE: Altered gut microbiota and metabolites are a major cause of non-alcoholic fatty liver disease (NAFLD) in children. This study demonstrated a complete gut metabolic map of children with NAFLD, containing 318 increased and 123 decreased metabolites by untargeted metabolomic. Multiple validation approaches (machine learning and targeted metabolomic) selected five novel gut metabolites for targeted metabolomics, which can distinguish NAFLD status and severity. The gut microbiota (Butyricicoccus and Alistipes) and metabolites (creatinine and dodecanoic acid) were novel biomarkers associated with impaired liver function and inflammation and validated by experiments of hepatocyte cell lines. The data provide a better understanding of the importance of gut microbiota and metabolite alterations in NAFLD, which implies that the altered gut microbiota and metabolites may represent a potential target to prevent NAFLD development.

Altered extracellular matrix dynamics is associated with insulin resistance in adolescent children with obesity.

OBJECTIVE: The objective of this study was to examine the hypothesis that abdominal and gluteal adipocyte turnover, lipid dynamics, and fibrogenesis are dysregulated among insulin-resistant (IR) compared with insulin-sensitive (IS) adolescents with obesity. METHODS: Seven IS and seven IR adolescents with obesity participated in a 3-h oral glucose tolerance test and a multi-section magnetic resonance imaging scan of the abdominal region to examine body fat distribution patterns and liver fat content. An 8-week 70% deuterated water (2 H2 O) labeling protocol examined adipocyte turnover, lipid dynamics, and fibrogenesis in vivo from biopsied abdominal and gluteal fat. RESULTS: Abdominal and gluteal subcutaneous adipose tissue (SAT) turnover rates of lipid components were similar among IS and IR adolescents with obesity. However, the insoluble collagen (type I, subunit α2) isoform measured from abdominal, but not gluteal, SAT was elevated in IR compared with IS individuals. In addition, abdominal insoluble collagen Iα2 was associated with ratios of visceral-to-total (visceral adipose tissue + SAT) abdominal fat and whole-body and adipose tissue insulin signaling, and it trended toward a positive association with liver fat content. CONCLUSIONS: Altered extracellular matrix dynamics, but not expandability, potentially decreases abdominal SAT lipid storage capacity, contributing to the pathophysiological pathways linking adipose tissue and whole-body IR with altered ectopic storage of lipids within the liver among IR adolescents with obesity.

Insufficient Bone Mineralization to Sustain Mechanical Load of Weight in Obese Boys: A Cross-Sectional Study.

CONTEXT: The increase in bone mineral content (BMC) and density (BMD) measured by dual-energy x-ray absorptiometry (DXA) in obese children may not sustain the mechanical load associated with weight, and the factors influencing bone mineralization are not well known. OBJECTIVE: We described bone mineralization in boys with overweight/obesity and leanness in relation to body composition. METHODS: Cross-sectional study in the Pediatric Endocrinology Unit of Angers University Hospital with 249 overweight/obese boys aged 8-18 who underwent DXA and insulin, testosterone, and IGF-1 measurements. Bone mineralization was compared with data from 301 lean boys of similar age and height from NHANES 2011-2015, using the same DXA model. Path analyses were performed to evaluate factors associated with total body less head (TBLH) BMC. RESULTS: The mean age- and height-adjusted difference in TBLH BMC between obese and lean boys was 241 ± 20 g/cm2. Each 1 kg/m2 increase in BMI was associated with +39 ± 6 g of TBLH BMC in lean subjects vs + 25 ± 3 g in obese subjects (P < .05). Each 1 kg/m2 increase in lean BMI (LBMI) was associated with +78 ± 5 g of TBLH BMC in lean and obese boys, and each 1 kg/m2 increase in fat mass index (FMI) was associated with a decrease of 9 ± 3 g of TBLH BMC. The TBLH BMC was directly positively influenced by LBMI and indirectly and positively influenced by IGF-1, testosterone, and insulin (mediated through height and LBMI). FMI indirectly influenced TBLH BMC, both positively through LBMI and negatively through its negative impact on IGF-1 and testosterone. CONCLUSION: The increase in bone mineralization in obese children does not adapt to the increase in body mass.

Associations of Adipocyte-derived Versican and Macrophage-derived Biglycan with Body Adipose Tissue and Hepatosteatosis in Obese Children

Objective: In animal models of obesity, adipocyte-derived versican, and macrophage-derived biglycan play a crucial role in mediating adipose tissue inflammation. The aim was to investigate levels of versican and biglycan in obese children and any potential association with body adipose tissue and hepatosteatosis. Methods: Serum levels of versican, biglycan, interleukin-6 (IL-6), and high sensitivity C-reactive protein (hsCRP) were measured by ELISA. Fat deposition in the liver, spleen, and subcutaneous adipose tissue was calculated using the IDEAL-IQ sequences in magnetic resonance images. Bioimpedance analysis was performed using the Tanita BC 418 MA device. Results: The study included 36 obese and 30 healthy children. The age of obese children was 13.6 (7.5-17.9) years, while the age of normal weight children was 13.0 (7.2-17.9) years (p=0.693). Serum levels of versican, hsCRP, and IL-6 were higher in the obese group (p=0.044, p=0.039, p=0.024, respectively), while no significant difference was found in biglycan levels between the groups. There was a positive correlation between versican, biglycan, hsCRP, and IL-6 (r=0.381 p=0.002, r=0.281 p=0.036, rho=0.426 p=0.001, r=0.424 p=0.001, rho=0.305 p=0.017, rho=0.748 p<0.001, respectively). Magnetic resonance imaging revealed higher segmental and global hepatic steatosis in obese children. There was no relationship between hepatic fat content and versican, biglycan, IL-6, and hsCRP. Versican, biglycan, hsCRP, and IL-6 were not predictive of hepatosteatosis. Body fat percentage >32% provided a predictive sensitivity of 81.8% and a specificity of 70.5% for hepatosteatosis [area under the curve (AUC): 0.819, p<0.001]. Similarly, a body mass index standard deviation score >1.75 yielded a predictive sensitivity of 81.8% and a specificity of 69.8% for predicting hepatosteatosis (AUC: 0.789, p<0.001). Conclusion: Obese children have higher levels of versican, hsCRP, and IL-6, and more fatty liver than their healthy peers.

Exercised breastmilk: a kick-start to prevent childhood obesity?

Exercise has systemic health benefits through effects on multiple tissues, with intertissue communication. Recent studies indicate that exercise may improve breastmilk composition and thereby reduce the intergenerational transmission of obesity. Even if breastmilk is considered optimal infant nutrition, there is evidence for variations in its composition between mothers who are normal weight, those with obesity, and those who are physically active. Nutrition early in life is important for later-life susceptibility to obesity and other metabolic diseases, and maternal exercise may provide protection against the development of metabolic disease. Here we summarize recent research on the influence of maternal obesity on breastmilk composition and discuss the potential role of exercise-induced adaptations to breastmilk as a kick-start to prevent childhood obesity.

Circulating extracellular vesicles are associated with pathophysiological condition including metabolic syndrome-related dysmetabolism in children and adolescents with obesity.

Obesity of children and adolescents (OCA) is often accompanied by metabolic syndrome (MetS), which often leads to adult obesity and subsequent complications, yet the entire pathophysiological response is not fully understood. The number and composition of circulating extracellular vesicles (EV) reflect overall patient condition; therefore, we investigated the pathophysiological condition of OCA, including MetS-associated dysmetabolism, using circulating EVs. In total, 107 children and adolescents with or without obesity (boys, n = 69; girls, n = 38; median age, 10 years) were enrolled. Circulating EV number and EV protein composition were assessed via flow cytometry and liquid chromatography tandem-mass spectrometry, respectively. In a multivariate analysis, relative body weight (standardized partial regression coefficient (SPRC) 0.469, P = 0.012) and serum triglyceride level (SPRC 0.548, P < 0.001) were detected as independent parameters correlating with circulating EV number. Proteomic analysis identified 31 upregulated and 45 downregulated EV proteins in OCA. Gene ontology analysis revealed upregulated proteins to be involved in various biological processes, including intracellular protein transport, protein folding, stress response, leukocyte activation, innate immune response, and platelet degranulation, which can modulate lipid and glucose metabolism, skeletal and cardiac muscle development, inflammation, immune response, carcinogenesis, and cancer progression. Notably, several identified EV proteins are involved in neuro-development, neurotransmitter release, and neuro-protective agents in OCA. Circulating EVs were derived from adipocytes, hepatocytes, B cell lymphocytes, and neurons. Circulating EV number is significantly associated with MetS-related dysmetabolism and the EV protein cargo carries a special "signature" that reflects the alteration of various biological processes under the pathophysiological condition of OCA. KEY MESSAGES: Circulating EV number correlates with physical and laboratory parameters for obesity in children and adolescents. Relative body weight and triglyceride are independent factors for increased circulating EVs. EV composition is significantly changed in obesity of children and adolescents. Identified EV composition changes associated with obesity and involves in metabolism, immune response, and cancer progression. Circulating EVs are partially derived from adipocyte, hepatocytes, B cells, and neurons.

Toxicity of Polystyrene Nanoplastics in the Liver and Intestine of Normal and High-Fat-Diet Juvenile Zebrafish.

Nanoplastics (NPs) are widely found and threaten environmental and biological safety, because they do not degrade completely. We aimed to preliminarily explore the toxicity of NPs in obese children, because childhood obesity is a growing global health concern. We used zebrafish as a vertebrate toxicological model to examine the hepatic lipid metabolism and gut microbiota in juvenile zebrafish exposed to 1000 µg/L polystyrene NPs and a high-fat diet (HFD) using Raman spectroscopy, pathological examination, transcriptome analysis, and 16S sequencing techniques. Our study showed that polystyrene NPs perturb the lipid metabolism and gut microbiota stability in zebrafish. Furthermore, the combined effects of polystyrene NPs and HFD resulted in gastrointestinal injury. Our study is one of the first to investigate the toxicity of polystyrene NPs to normal-diet and HFD juvenile zebrafish using confocal Raman spectroscopy. Our results show the importance of a healthy diet and a reduction in the use of plasticware. Environ Toxicol Chem 2024;43:147-158. © 2023 SETAC.

Proinflammatory pattern in the lower airways of non-asthmatic obese adolescents.

BACKGROUND: Obesity is known to be a pro-inflammatory condition affecting multiple organs. Obesity as a systemic pro-inflammatory state, might be associated with bronchial inflammation in non-smoking adolescents with a BMI ≥ 30 kg/m2 without evidence of concomitant chronic diseases. MATERIALS AND METHODS: We studied non-asthmatic obese patients (n = 20; median age 15.8 years; BMI 35.0 kg/m2) compared to age matched healthy control subjects (n = 20; median age 17.5 years; BMI 21.5 kg/m2). Induced sputum differential cell counts and sputum mRNA levels were assessed for all study subjects. Serum levels of CRP, IL-6, and IL-8 were measured. Further, IL-5, IL-6, IL-8, IL-13, IL-17, TNF-α, IFN-γ, and IP-10 protein levels were analyzed in induced sputum was. RESULTS: Serum CRP levels, sputum inflammatory cell load and sputum eosinophils differed significantly between obese and non-obese subjects, for sputum neutrophils, a correlation was shown with BMI ≥ 30 kg/m2. Differences were also observed for sputum mRNA expression of IL6, IL8, IL13, IL17, IL23, and IFN-γ, as well as the transcription factors T-bet, GATA3, and FoxP3. CONCLUSIONS: Increased bronchial inflammation, triggered by systemic or local inflammatory effects of obesity itself, may account for the higher rates of airway disease in obese adolescents.

Loss of Uncoupling Protein 1 Expression in the Subcutaneous Adipose Tissue Predicts Childhood Obesity.

Stimulation of thermogenesis by inducing uncoupling protein 1 (UCP1) expression in adipocytes is thought to promote weight loss by increasing energy expenditure, and it is postulated that the human newborn has thermogenic subcutaneous fat depots. However, it remains unclear whether a relevant number of UCP1-expressing (UCP1+) adipocytes exist in the early postnatal life. Here we studied the distribution of UCP1 and the expression of thermogenic genes in the subcutaneous adipose tissues of the human fetus, infant and child. We show that the deep layer of human fetal and neonatal subcutaneous fat, particularly the abdominal wall, is rich in UCP1+ adipocytes. These adipocytes develop in the late third trimester and persist throughout childhood, expressing a panel of genes linked to mitochondrial biogenesis and thermogenesis. During the early childhood adiposity rebound-a critical phase that determines obesity risk later in life-the absence of adipose tissue UCP1 expression in children with normal body mass index (BMI) correlates with an obesity-associated gene expression signature. Finally, UCP1 expression is negatively correlated with BMI z-score and adipocyte size in infants and children. Overall, our results show that the absence of UCP1 expression in adipose tissue is an early indicator of adipose tissue expansion in children.

The Protective Effects of Cinnamyl Alcohol Against Hepatic Steatosis, Oxidative and Inflammatory Stress in Nonalcoholic Fatty Liver Disease Induced by Childhood Obesity.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is characterized by excessive intracellular lipid accumulation, oxidative stress, and inflammation. Cinnamyl alcohol (CA), one of the cinnamon extracts, has been shown to exhibit anti-oxidative and anti-inflammatory activities. We proposed that CA was beneficial to NAFLD. METHODS: Serum cytokines and components of the lipid metabolism were determined in children with NAFLD against age-matched comparisons. A NAFLD mouse model was established by high fat and high carbohydrate (HFHC) diet in male C57BL/6 mouse pups, followed by administration of CA. The effects of CA on lipid metabolism, oxidative stress, and inflammation in hepatic tissues were assessed. RESULTS: Abnormal lipid metabolism and inflammatory responses were observed in the children with NAFLD as compared with the controls. CA reduced the weight of obese mice without affecting food intake as well as alleviating liver injury caused by HFHC feeding. CA was found to mitigate dyslipidemia and reduce hepatic steatosis in HFHC-fed mice by down-regulating genes related to lipogenesis, including peroxisome proliferator-activated receptor gamma (PPARγ), sterol regulatory element-binding transcription factor-1c (SREBP-1c), and acetyl-CoA carboxylase 1 (ACC1). Additionally, CA treatment reversed HFHC-induced oxidative stress and inflammation, evidenced by the decreased liver reactive oxygen species (ROS), hepatic inflammatory cytokine levels, and F4/80-positive macrophage infiltration in HFHC diet mice. CA reduced the protein levels of pyrin domain-containing protein 3 (NLRP3), adapter protein apoptosis-associated speck-like protein (ASC), and caspase-1 in the liver tissues significantly. CONCLUSION: CA alleviates HFHC-induced NAFLD in mice, which is associated with the amelioration in lipid metabolism, oxidative stress, and inflammation.

CD8 cytotoxic T-cell infiltrates and cellular damage in the hypothalamus in human obesity.

Rare cases of paraneoplastic obesity in children suggest sporadic obesity might also arise from an adaptive immune cell-mediated mechanism. Since the hypothalamus is a central regulator of feeding behavior and energy expenditure, we quantified lymphocytic inflammation in this region in a cohort of obese and non-obese human post-mortem brains. We report that CD8-positive cytotoxic T-cells are increased in hypothalamic median eminence/arcuate nucleus (ME/Arc) and bed nucleus of the stria terminalis in 40% of obese compared to non-obese patients, but not in other hypothalamic nuclei or brain regions. CD8 T-cells were most abundant in individuals with concurrent obesity and diabetes. Markers of cytotoxic T-cell induced damage, activated caspase 3 and poly-ADP ribose, were also elevated in the ME/Arc of obese patients. To provoke CD8 cytotoxic T-cell infiltrates in ventromedial region of hypothalamus in mice we performed stereotactic injections of an adeno-associated virus expressing immunogenic green fluorescent protein or saline. AAV but not saline injections triggered hypothalamic CD8 T-cell infiltrates associated with a rapid weight gain in mice recapitulating the findings in human obesity. This is the first description of the neuropathology of human obesity and when combined with its reconstitution in a mouse model suggests adaptive immunity may drive as much as 40% of the human condition.

Macrophage-associated markers of metaflammation are linked to metabolic dysfunction in pediatric obesity.

BACKGPOUND: Metabolically driven chronic low-grade adipose tissue inflammation, so-called metaflammation, is a central feature in obesity. This inflammatory tone is largely driven by adipose tissue macrophages (ATM), which express pro- and anti-inflammatory markers and cytokines such as, e.g., IL-1 receptor antagonist (IL-1RA), CD163 and osteopontin (OPN). Metaflammation ultimately leads to the development of cardiometabolic diseases. This study aimed to evaluate the association between selected adipose tissue macrophage-associated markers and metabolic comorbidities in pediatric obesity. METHODS: From a pediatric cohort with obesity (n = 108), clinically thoroughly characterized including diverse routine blood parameters, oral glucose tolerance test and liver MRI, plasma IL-1RA, soluble (s)CD163 and OPN were measured by ELISA. RESULTS: We observed significantly higher IL-1RA, sCD163, and OPN levels in the plasma of children with metabolic-dysfunction associated fatty liver disease (MAFLD) and metabolic syndrome. Moreover, IL-1RA and sCD163 correlated with hepatic disease and apoptosis markers alanine aminotransferase and CK-18. IL-1RA concentrations additionally correlated with insulin resistance, while children with disturbed glucose metabolism had significantly higher levels of sCD163. CONCLUSION: MAFLD and other metabolic disorders in pediatric patients with obesity are associated with an elevation of adipose tissue macrophage-related inflammation markers.

Metformin restores prohormone processing enzymes and normalizes aberrations in secretion of proinsulin and insulin in palmitate-exposed human islets.

AIM: To elucidate how proinsulin synthesis and insulin was affected by metformin under conditions of nutrient overstimulation. MATERIALS AND METHODS: Isolated human pancreatic islets from seven donors were cultured at 5.5 mmol/L glucose and 0.5 mmol/L palmitate for 12, 24 or 72 h. Metformin (25 µmol/L) was introduced after initial 12 h with palmitate. Proinsulin and insulin were measured. Expression of prohormone convertase 1/3 (PC1/3) and carboxypeptidase E (CPE), was determined by western blot. Adolescents with obesity, treated with metformin and with normal glucose tolerance (n = 5), prediabetes (n = 14), or type 2 diabetes (T2DM; n = 7) were included. Fasting proinsulin, insulin, glucose, 2-h glucose and glycated haemoglobin were measured. Proinsulin/insulin ratio (PI/I) was calculated. RESULTS: In human islets, palmitate treatment for 12 and 24 h increased proinsulin and insulin proportionally. After 72 h, proinsulin but not insulin continued to increase which was coupled with reduced expression of PC1/3 and CPE. Metformin normalized expression of PC1/3 and CPE, and proinsulin and insulin secretion. In adolescents with obesity, before treatment, fasting proinsulin and insulin concentrations were higher in subjects with T2DM than with normal glucose tolerance. PI/I was reduced after metformin treatment in subjects with T2DM as well as in subjects with prediabetes, coupled with reduced 2-h glucose and glycated haemoglobin. CONCLUSIONS: Metformin normalized proinsulin and insulin secretion after prolonged nutrient-overstimulation, coupled with normalization of the converting enzymes, in isolated islets. In adolescents with obesity, metformin treatment was associated with improved PI/I, which was coupled with improved glycaemic control.

Childhood obesity: Implications on adipose tissue dynamics and metabolic health.

Obesity is the leading risk factor for the development of type 2 diabetes and cardiovascular diseases. Childhood obesity represents an alarming health challenge because children with obesity are prone to remain with obesity throughout their life and have an increased morbidity and mortality risk. The ability of adipose tissue to store lipids and expand in size during excessive calorie intake is its most remarkable characteristic. Cellular and lipid turnovers determine adipose tissue size and are closely related with metabolic status. The mechanisms through which adipose tissue expands and how this affects systemic metabolic homeostasis are still poorly characterized. Furthermore, the mechanism through which increased adiposity extends from childhood to adulthood and its implications in metabolic health are in most part, still unknown. More studies on adipose tissue development in healthy and children with obesity are urgently needed. In the present review, we summarize the dynamics of white adipose tissue, from developmental origins to the mechanisms that allows it to grow and expand throughout lifetime and during obesity in children and in different mouse models used to address this largely unknown field. Specially, highlighting the role that excessive adiposity during the early life has on future's adipose tissue dynamics and individual's health.