Metabolic endotoxaemia in childhood obesity

Low Grade Endotoxemia and Oxidative Stress in Offspring of Patients with Early Myocardial Infarction

Background and aims: Offspring of patients with early myocardial infarction are at higher cardiovascular risk, but the underlying physio-pathological mechanism is unclear. NADPH oxidase-type 2 (NOX-2) plays a pivotal role as mediator of oxidative stress and could be involved in activating platelets in these patients. Furthermore, altered intestinal permeability and serum lipopolysaccharide (LPS) could be a trigger to promote NOX-2 activation and platelet aggregation. This study aims to evaluate the behavior of low grade endotoxemia, oxidative stress and platelet activation in offspring of patients with early myocardial infarction. Methods: We enrolled, in a cross-sectional study, 46 offspring of patients with early myocardial infarction and 86 healthy subjects (HS). LPS levels and gut permeability (assessed by zonulin), oxidative stress (assessed by serum NOX-2-derived peptide (sNOX2-dp) release, hydrogen peroxide (H₂O₂) production and isoprostanes), serum nitric oxide (NO) bioavailability and platelet activation (by serum thromboxane B2 (TXB2) and soluble P-Selectin (sP-Selectin)) were analyzed. Results: Compared to HS, offspring of patients with early myocardial infarction had higher values of LPS, zonulin, serum isoprostanes, sNOX2-dp H₂O₂, TXB2, p-selectin and lower NO bioavailability. Logistic regression analysis showed that the variables associated with offspring of patients with early myocardial infarction were LPS, TXB2 and isoprostanes. The multiple linear regression analysis confirmed that serum NOX-2, isoprostanes, p-selectin and H₂O₂ levels were significantly associated to LPS. Furthermore, serum LPS, isoprostanes and TXB2 levels were significantly associated with sNOX-2-dp. Conclusions: Offspring of patients with early myocardial infarction have a low grade endotoxemia that could generate oxidative stress and platelet activation increasing their cardiovascular risk. Future studies are needed to understand the role of dysbiosis in this population.

The impact of metabolic endotoxaemia on the browning process in human adipocytes

BACKGROUND

Dysfunctional adipose tissue (AT) is known to contribute to the pathophysiology of metabolic disease, including type 2 diabetes mellitus (T2DM). This dysfunction may occur, in part, as a consequence of gut-derived endotoxaemia inducing changes in adipocyte mitochondrial function and reducing the proportion of BRITE (brown-in-white) adipocytes. Therefore, the present study investigated whether endotoxin (lipopolysaccharide; LPS) directly contributes to impaired human adipocyte mitochondrial function and browning in human adipocytes, and the relevant impact of obesity status pre and post bariatric surgery.

METHODS

Human differentiated abdominal subcutaneous (AbdSc) adipocytes from participants with obesity and normal-weight participants were treated with endotoxin to assess in vitro changes in mitochondrial function and BRITE phenotype. Ex vivo human AbdSc AT from different groups of participants (normal-weight, obesity, pre- and 6 months post-bariatric surgery) were assessed for similar analyses including circulating endotoxin levels.

RESULTS

Ex vivo AT analysis (lean & obese, weight loss post-bariatric surgery) identified that systemic endotoxin negatively correlated with BAT gene expression (p < 0.05). In vitro endotoxin treatment of AbdSc adipocytes (lean & obese) reduced mitochondrial dynamics (74.6% reduction; p < 0.0001), biogenesis (81.2% reduction; p < 0.0001) and the BRITE phenotype (93.8% reduction; p < 0.0001). Lean AbdSc adipocytes were more responsive to adrenergic signalling than obese AbdSc adipocytes; although endotoxin mitigated this response (92.6% reduction; p < 0.0001).

CONCLUSIONS

Taken together, these data suggest that systemic gut-derived endotoxaemia contributes to both individual adipocyte dysfunction and reduced browning capacity of the adipocyte cell population, exacerbating metabolic consequences. As bariatric surgery reduces endotoxin levels and is associated with improving adipocyte functionality, this may provide further evidence regarding the metabolic benefits of such surgical interventions.

Toll-like receptor 4 and myeloid differentiation factor 88 are required for gastric bypass-induced metabolic effects

Background:

Toll-like receptor 4 (TLR4) has been suggested as one of the forefront cross-communicators between the intestinal bacteria and the host to regulate inflammatory signals and energy homeostasis. High-fat diet–induced inflammation is mediated by changes in gut microbiota and requires a functional TLR-4, the deficiency of which renders mice resistant to diet-induced obesity and its associated metabolic dysfunction. Furthermore, gut microbiota was suggested to play a key role in the beneficial effects of Roux-en-Y gastric bypass (RYGB), a commonly performed bariatric procedure.

Objectives:

To explore whether TLR4, myeloid differentiation factor 8 (MyD88; 1 of its key downstream signaling regulators) and gut microbiota play an integrative role in RYGB-induced metabolic outcomes.

Setting:

Animal-based study.

Method:

We performed RYGB in TLR4 and MyD88 knock-out (KO) mice and used fecal microbiota transplant (FMT) from RYGB-operated animals to these genetic mouse models to address our questions.

Results:

We demonstrate that RYGB reduces TLR4 expression explicitly in the small and large intestine of C57Blc/6J mice. We also show that TLR4 KO mice have an attenuated glucoregulatory response to RYGB. In addition, we reveal that MyD88 KO mice fail to respond to all RYGB-induced metabolic effects. Finally, fecal microbiota transplant from RYGB-operated mice into TLR4 KO and MyD88 KO naïve recipients fails to induce a metabolic phenotype similar to that of the donors, as it does in wild-type recipients.

Conclusion:

TLR4 and MyD88 are required for RYGB-induced metabolic response that is likely mediated by gut microbiome.

Methodology of an exercise intervention program using social incentives and gamification for obese children

BACKGROUND

Traditional exercise [supervised exercise (SE)] intervention has been proved to be one of the most effective ways to improve metabolic health. However, most exercise interventions were on a high-cost and small scale, moreover lacking of the long-term effect due to low engagement. On the other hand, it was noteworthy that gamification and social incentives were promising strategies to increase engagement and sustain exercise interventions effects; as well as mobile technologies such as WeChat also can provide an appropriate platform to deploy interventions on a broader, low-cost scale. Thus, we aim to develop a novel exercise intervention ('S&G exercise intervention') that combines SE intervention with gamification and social incentives design through WeChat, with the aim of improving metabolic health and poor behaviors among overweight and obesity children.

METHODS

We propose a randomized controlled trial of a 'S&G exercise intervention' among 420 overweight and obese children who have at least one marker of metabolic syndrome. Children will be randomized to control or intervention group in a 1:1 ratio. The exercise intervention package includes intervention designs based on integrated social incentives and gamification theory, involving targeted essential volume and intensity of activity (skipping rope) as well as monitoring daily information and providing health advice by WeChat. Participants will undertake assessments at baseline, at end of intervention period, in the follow-up time at months 3,6,12. The primary outcome is outcome of metabolic health. Secondary outcomes include behavioral (e.g., diary physical activity, diet) and anthropometric measures (e.g., body fat rate and muscle mass).

DISCUSSIONS

This will be the first study to design an exercise intervention model that combines traditional supervised exercise (SE) intervention with gamification and social incentives theory through WeChat. We believed that this study could explore a low-cost, easy-to-popularize, and effective exercise intervention model for improving metabolic health and promote healthy among obese children. Furthermore, it will also provide important evidence for guidelines to prevent and improve metabolic health and health behaviors.

TRIAL REGISTRATION

10-04-2019;Registration number: ChiCTR1900022396 .

Metabolic Abnormalities in Normal Weight Children Are Associated with Increased Visceral Fat Accumulation, Elevated Plasma Endotoxin Levels and a Higher Monosaccharide Intake

Being overweight has been identified as the main risk factor for the development of metabolic disorders in adults and children. However, recent studies suggest that normal weight individuals are also frequently affected by metabolic abnormalities with underlying mechanisms not yet fully understood. The aim of the present study was to determine if dietary pattern and markers of intestinal permeability, as well as inflammation, differ between normal weight healthy children and normal weight children suffering from metabolic abnormalities. In total, 45 normal weight children aged 5–9 years were included in the study, of whom nine suffered from metabolic abnormalities. Anthropometric data, dietary intake and markers of inflammation, as well as intestinal permeability, were assessed in fasting blood samples. Neither BMI nor BMI-SDS differed between groups; however, children with metabolic abnormalities had a significantly larger waist circumference (+~5 cm) and a higher leptin to adiponectin ratio. While plasma leptin levels are significantly higher in normal weight children with metabolic abnormalities, neither TNF α nor sCD14, adiponectin, PAI-1 or IL-6 plasma levels differed between groups. Despite similar total calorie and macronutrient intake between groups, mean total fructose and total glucose intake (resulting mainly from sugar sweetened beverages, fruits and sweets) were higher in children with metabolic abnormalities than in healthy children. Time spent physically active was significantly higher in healthy normal weight children whereas time spent physically inactive was similar between groups. Furthermore, bacterial endotoxin levels were significantly higher in the peripheral plasma of normal weight children with metabolic abnormalities than in healthy normal weight children. Our results suggest that metabolic disorders in normal weight children are associated with a high monosaccharide intake and elevated bacterial endotoxin as well as leptin plasma levels, the latter also discussed as being indicative of visceral adiposity.

Perioperative considerations for airway management and drug dosing in obese children

PURPOSE OF REVIEW

Childhood obesity, a phenomenon that is increasing globally, holds substantial relevance for pediatric anesthesia. In particular, understanding the nuances of airway management and drug dosing in obese children can be daunting.

RECENT FINDINGS

Respiratory adverse events and challenges in managing the airway may be anticipated. In addition, drug-dosing strategies for the obese child are complex and poorly understood although recent advances have clarified the optimal dosing for anesthetics in these children.

SUMMARY

Theoretical knowledge, practical skills, meticulous risk stratification and optimal drug regimens are crucial to ensure the safe conduct of anesthesia for obese children.

Prebiotics Reduce Body Fat and Alter Intestinal Microbiota in Children Who Are Overweight or With Obesity

BACKGROUND & AIMS

It might be possible to manipulate the intestinal microbiota with prebiotics or other agents to prevent or treat obesity. However, little is known about the ability of prebiotics to specifically modify gut microbiota in children with overweight/obesity or reduce body weight. We performed a randomized controlled trial to study the effects of prebiotics on body composition, markers of inflammation, bile acids in fecal samples, and composition of the intestinal microbiota in children with overweight or obesity.

METHODS

We performed a single-center, double-blind, placebo-controlled trial of 2 separate cohorts (March 2014 and August 2014) at the University of Calgary in Canada. Participants included children, 7-12 years old, with overweight or obesity (>85th percentile of body mass index) but otherwise healthy. Participants were randomly assigned to groups given either oligofructose-enriched inulin (OI; 8 g/day; n=22) or maltodextrin placebo (isocaloric dose, controls; n=20) once daily for 16 weeks. Fat mass and lean mass were measured using dual-energy-x-ray absorptiometry. Height, weight, and waist circumference were measured at baseline and every 4 weeks thereafter. Blood samples were collected at baseline and 16 weeks, and analyzed for lipids, cytokines, lipopolysaccharide, and insulin. Fecal samples were collected at baseline and 16 weeks; bile acids were profiled using high-performance liquid chromatography and the composition of the microbiota was analyzed by 16S rRNA sequencing and quantitative polymerase chain reaction. The primary outcome was change in percent body fat from baseline to 16 weeks.

RESULTS

After 16 weeks, children who consumed OI had significant decreases in body weight z-score (decrease of 3.1%), percent body fat (decrease of 2.4%), and percent trunk fat (decrease of 3.8%) compared with children given placebo (increase of 0.5%, increase of 0.05%, and decrease of 0.3%, respectively). Children who consumed OI also had a significant reduction in level of interleukin 6 from baseline (decrease of 15%) compared with the placebo group (increase of 25%). There was a significant decrease in serum triglycerides (decrease of 19%) in the OI group. Quantitative polymerase chain reaction showed a significant increase in Bifidobacterium spp. in the OI group compared with controls. 16S rRNA sequencing revealed significant increases in species of the genus Bifidobacterium and decreases in Bacteroides vulgatus within the group who consumed OI. In fecal samples, levels of primary bile acids increased in the placebo group but not in the OI group over the 16-week study period.

CONCLUSIONS

In a placebo-controlled, randomized trial, we found a prebiotic (OI) to selectively alter the intestinal microbiota and significantly reduce body weight z-score, percent body fat, percent trunk fat, and serum level of interleukin 6 in children with overweight or obesity (Clinicaltrials.gov no: NCT02125955).

Microbial Impact on Host Metabolism: Opportunities for Novel Treatments of Nutritional Disorders?

Malnutrition is the cause of major public health concerns worldwide. On the one hand, obesity and associated pathologies (also known as the metabolic syndrome) affect more than 10% of the world population. Such pathologies might arise from an elevated inflammatory tone. We have discovered that the inflammatory properties of high-fat diets were linked to the translocation of lipopolysaccharide (LPS). We proposed a mechanism associating the gut microbiota with the onset of insulin resistance and low-grade inflammation, a phenomenon that we called “metabolic endotoxemia.” We and others have shown that bacteria as well as host-derived immune-related elements control microbial communities and eventually contribute to the phenotype observed during diet-induced obesity, diabetes, and metabolic inflammation. On the other hand, undernutrition is one of the leading causes of death in children. A diet poor in energy and/or nutrients causes incomplete development of the gut microbiota and may profoundly affect energy absorption, initiating stunted growth, edema, and diarrhea. In this review, we discuss how changes in microbiota composition are associated with obesity and undernutrition. We also highlight that opposite consequences exist in terms of energy absorption from the diet (obesity versus undernutrition), but interestingly the two situations share similar defects in term of diversity, functionality, and inflammatory potential.

The initiation of metabolic inflammation in childhood obesity

An understanding of the events that initiate metabolic inflammation (metainflammation) can support the identification of targets for preventing metabolic disease and its negative effects on health. There is ample evidence demonstrating that the initiating events in obesity-induced inflammation start early in childhood. This has significant implications on our understanding of how early life events in childhood influence adult disease. In this Review we frame the initiating events of metainflammation in the context of child development and discuss what this reveals about the mechanisms by which this unique form of chronic inflammation is initiated and sustained into adulthood.

Apolipoprotein E4, Gender, Body Mass Index, Inflammation, Insulin Resistance, and Air Pollution Interactions: Recipe for Alzheimer's Disease Development in Mexico City Young Females

Given the epidemiological trends of increasing Alzheimer's disease (AD) and growing evidence that exposure and lifestyle factors contribute to AD risk and pathogenesis, attention should be paid to variables such as air pollution, in order to reduce rates of cognitive decline and dementia. Exposure to fine particulate matter (PM2.5) and ozone (O3) above the US EPA standards is associated with AD risk. Mexico City children experienced pre- and postnatal high exposures to PM2.5, O3, combustion-derived iron-rich nanoparticles, metals, polycyclic aromatic hydrocarbons, and endotoxins. Exposures are associated with early brain gene imbalance in oxidative stress, inflammation, innate and adaptive immune responses, along with epigenetic changes, accumulation of misfolded proteins, cognitive deficits, and brain structural and metabolic changes. The Apolipoprotein E (APOE) 4 allele, the most prevalent genetic risk for AD, plays a key role in the response to air pollution in young girls. APOE 4 heterozygous females with >75% to <94% BMI percentiles are at the highest risk of severe cognitive deficits (1.5-2 SD from average IQ). This review focused on the relationships between gender, BMI, systemic and neural inflammation, insulin resistance, hyperleptinemia, dyslipidemia, vascular risk factors, and central nervous system involvement in APOE4 urbanites exposed to PM2.5 and magnetite combustion-derived iron-rich nanoparticles that can reach the brain. APOE4 young female heterozygous carriers constitute a high-risk group for a fatal disease: AD. Multidisciplinary intervention strategies could be critical for prevention or amelioration of cognitive deficits and long-term AD progression in young individuals at high risk.

Toxins, Toxicity, and Endotoxemia: A Historical and Clinical Perspective for Chiropractors

OBJECTIVE

The purpose of this commentary is to review the notion of toxicity in the context of chiropractic practice.

DISCUSSION

The belief that body toxicity is the cause of disease has been promoted for thousands of years. Prior to the emergence of the chiropractic profession, the medical profession embraced the notion that the body becomes "toxic," requiring detoxification interventions or surgery. The legacy of body toxicity within the chiropractic approach to patient care began with Daniel David Palmer. Today, some sectors within the medical and chiropractic professions continue to embrace the concept of body toxicity and the related need to engage in detoxifying treatments. The most common areas of focus for detoxification are the intestines and liver; however, the nature of the toxicity in these organs has yet to be defined or measured. In contrast, diet-induced systemic bacterial endotoxemia is a measureable state that is known to be promoted by a diet rich in sugar, flour, and refined oil. This suggests that bacterial endotoxin may be a candidate toxin to consider in the clinical context, as many common conditions, such as obesity, metabolic syndrome, diabetes, interstitial cystitis, depression, and migraine headache, are known to be promoted by endotoxemia.

CONCLUSION

A diet rich in refined sugar, flour, and oils may induce proinflammatory changes within intestinal microbiota that lead to systemic, low-grade endotoxemia, which is a common variety of "toxicity" that is measurable and worthy of research consideration. Introducing a diet to reduce endotoxemia, rather than attempting to target a specific organ, appears to be a rational clinical approach for addressing the issue of toxicity.

Interactive and additive influences of Gender, BMI and Apolipoprotein 4 on cognition in children chronically exposed to high concentrations of PM2.5 and ozone. APOE 4 females are at highest risk in Mexico City

Children's air pollution exposures are associated with systemic and brain inflammation and the early hallmarks of Alzheimer's disease (AD). The Apolipoprotein E (APOE) 4 allele is the most prevalent genetic risk for AD, with higher risk for women. We assessed whether gender, BMI, APOE and metabolic variables in healthy children with high exposures to ozone and fine particulate matter (PM2.5) influence cognition. The Wechsler Intelligence Scale for Children (WISC-R) was administered to 105 Mexico City children (12.32±5.4 years, 69 APOE 3/3 and 36 APOE 3/4). APOE 4v 3 children showed decrements on attention and short-term memory subscales, and below-average scores in Verbal, Performance and Full Scale IQ. APOE 4 females had higher BMI and females with normal BMI between 75-94% percentiles had the highest deficits in Total IQ, Performance IQ, Digit Span, Picture Arrangement, Block Design and Object Assembly. Fasting glucose was significantly higher in APOE 4 children p=0.006, while Gender was the main variable accounting for the difference in insulin, HOMA-IR and leptin (p<.05). Gender, BMI and APOE influence children's cognitive responses to air pollution and glucose is likely a key player. APOE 4 heterozygous females with >75% to <94% BMI percentiles are at the highest risk of severe cognitive deficits (1.5-2SD from average IQ). Young female results highlight the urgent need for gender-targeted health programmes to improve cognitive responses. Multidisciplinary intervention strategies could provide paths for prevention or amelioration of female air pollution targeted cognitive deficits and possible long-term AD progression.