The role of the gut microbiota on the metabolic status of obese children

Self-Initiated Dietary Adjustments Alter Microbiota Abundances: Implications for Perceived Health

Background/Objectives: Personalized and self-initiated dietary adjustments have been shown to alleviate mental and somatic complaints. Here, we investigated the potential role of gut microbiome alterations underlying these effects. Methods: For this purpose, participants (n = 185) underwent a four-week self-initiated dietary intervention and filled out weekly questionnaires on their dietary intake, somatic and mental symptoms, and physical activity. Results: Overall, the participants lost weight, had alleviated mental and somatic complaints, reduced their total caloric and percentual carbohydrate intake, and ate less processed, party-type, and traditional Dutch food items, but ate more Pescatarian type food items, while keeping their fiber intake unaltered. Baseline and endpoint gut microbiota analyses using 16S rRNA gene sequencing revealed an overall increase in Gemmiger formicilis and reductions in Peptostreptococcaceae and Ruminococcus bromii over the four-week dietary intervention. While these bacterial alterations were considered to be beneficial for the host, they were not individually correlated with alterations in, or endpoint levels of, somatic and/or mental complaints. Instead, individual increases in Ruminococcus bicirculans (a well-known utilizer of plant cell wall polysaccharides) were strongly correlated with reductions in mental complaints, even though overall R. bicirculans remained unaltered over the course of the four-week self-initiated dierary intervention. Conclusions: Our results suggest that overall altered versus individually correlated microbiota abundances and their relations with host health characteristics over the course of a self-chosen dietary intervention may represent different levels of regulation, which remain to be further untangled.

The Combination of Exercise and Konjac Glucomannan More Effectively Prevents Antibiotics-Induced Dysbiosis in Mice Compared with Singular Intervention

Our previous studies have demonstrated that konjac glucomannan (KGM) can prevent dysbiosis induced by antibiotics. While exercise may also impact the gut microbiome, there are limited studies reporting its protective effect on antibiotic-induced dysbiosis. Therefore, this study investigated the preventive and regulatory effects of a combination of 6-week exercise and KGM intervention on antibiotic-induced dysbiosis in C57BL/6J mice compared with a single intervention. The results showed that combined exercise and KGM intervention could restore the changes in the relative abundance of Bacteroides (3.73% with CTL versus 14.23% with ATBX versus 4.46% with EK) and Prevotellaceae_Prevotella (0.33% with CTL versus 0.00% with ATBX versus 0.30% with EK) induced by antibiotics (p < 0.05), and minimized the Bray-Curtis distance induced by antibiotics (0.55 with CTL versus 0.81 with ATBX versus 0.80 with EXC versus 0.83 with KGM versus 0.75 with EK). Compared with the combined intervention, exercise intervention also produced a certain level of recovery effects; the relative abundance of Rikenellaceae (1.96% with CTL versus 0.09% with ATBX versus 0.49% with EXC) was restored, while KGM supplementation showed the best preventive effect. In addition, the combination of exercise and KGM significantly enriched microbial purine metabolic pathways (p < 0.05). These findings indicate that combining exercise with KGM could be a promising approach to reducing the side effects of antibiotics on the gut microbiome.

Metagenomics-Metabolomics Exploration of Three-Way-Crossbreeding Effects on Rumen to Provide Basis for Crossbreeding Improvement of Sheep Microbiome and Metabolome of Sheep

The objective of this experiment was to explore the effects of three-way hybridization on rumen microbes and metabolites in sheep using rumen metagenomics and metabolomics. Healthy Hu and CAH (Charolais × Australian White × Hu) male lambs of similar birth weight and age were selected for short-term fattening after intensive weaning to collect rumen fluid for sequencing. Rumen metagenomics diversity showed that Hu and CAH sheep were significantly segregated at the species, KEGG-enzyme, and CAZy-family levels. Moreover, the CAH significantly increased the ACE and Chao1 indices. Further, correlation analysis of the abundance of the top 80 revealed that the microorganisms were interrelated at the species, KEGG-enzyme, and CAZy-family levels. Overall, the microbiome significantly affected metabolites of the top five pathways, with the strongest correlation found with succinic acid. Meanwhile, species-level microbial markers significantly affected rumen differential metabolites. In addition, rumen microbial markers in Hu sheep were overall positively correlated with down-regulated metabolites and negatively correlated with up-regulated metabolites. In contrast, rumen microbial markers in CAH lambs were overall negatively correlated with down-regulated metabolites and positively correlated with up-regulated metabolites. These results suggest that three-way crossbreeding significantly affects rumen microbial community and metabolite composition, and that significant interactions exist between rumen microbes and metabolites.

Pro- and anti-inflammatory cytokines are the game-changers in childhood obesity-associated metabolic disorders (diabetes and non-alcoholic fatty liver diseases)

Childhood obesity is a chronic inflammatory epidemic that affects children worldwide. Obesity affects approximately 1 in 5 children worldwide. Obesity in children can worsen weight gain and raise the risk of obesity-related comorbidities like diabetes and non-alcoholic fatty liver disease (NAFLD). It can also negatively impact the quality of life for these children. Obesity disrupts immune system function, influencing cytokine (interleukins) balance and expression levels, adipokines, and innate and adaptive immune cells. The altered expression of immune system mediators, including interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-17 (IL-17), interleukin-18 (IL-18), transforming growth factor (TGF), tumor necrosis factor (TNF), and others, caused inflammation, progression, and the development of pediatric obesity and linked illnesses such as diabetes and NAFLD. Furthermore, anti-inflammatory cytokines, including interleukin-2 (IL-2), have been shown to have anti-diabetes and IL-1 receptor antagonist (IL-1Ra) anti-diabetic and pro-NAFLFD properties, and interleukin-10 (IL-10) has been shown to have a dual role in managing diabetes and anti-NAFLD. In light of the substantial increase in childhood obesity-associated disorders such as diabetes and NAFLD and the absence of an effective pharmaceutical intervention to inhibit immune modulation factors, it is critical to consider the alteration of immune system components as a preventive and therapeutic approach. Thus, the current review focuses on the most recent information regarding the influence of pro- and anti-inflammatory cytokines (interleukins) and their molecular mechanisms on pediatric obesity-associated disorders (diabetes and NAFLD). Furthermore, we discussed the current therapeutic clinical trials in childhood obesity-associated diseases, diabetes, and NAFLD.

Multivariate Analysis and Correlation Study Shows the Impact of Anthropometric and Demographic Variables on Gut Microbiota in Obese Egyptian Children

Deciphering the gut microbiome's link to obesity is crucial. Our study characterized the gut microbial community in Egyptian children and investigated the effect of covariates on the gut microbiome, body mass index (BMI), geographical location, gender, and age. We used 16S rRNA sequencing to characterize the gut microbial communities of 49 children. We then evaluated these communities for diversity, potential biomarkers, and functional capacity. Alpha diversity of the non-obese group was higher than that of the obese group (Chao1, P = 0.006 and observed species, P = 0.003). Beta diversity analysis revealed significant variations in the gut microbiome between the two geographical locations, Cairo and Ismailia (unweighted UniFrac, P = 0.03) and between obesity statuses, obese and non-obese (weighted UniFrac, P = 0.034; unweighted UniFrac, P = 0.015). We observed a significantly higher Firmicutes/Bacteroidetes ratio in obese males than in non-obese males (P = 0.004). Interestingly, this difference was not seen in females (P = 0.77). Multivariable association with linear models (MaAsLin2) identified 8 microbial features associated with obesity, 12 associated with non-obesity, and found 29 and 13 features specific to Cairo and Ismailia patients, respectively. It has also shown one microbial feature associated with patients under five years old. MaAsLin2, however, failed to recognize any association between gender and the gut microbiome. Moreover, it could find the most predominant features in groups 2-9 but not in group 1. Another method used in the analysis is the Linear discriminant analysis Effect Size (LEfSe) approach, which effectively identified 19 biomarkers linked to obesity, 9 linked non-obesity, 20 linked to patients residing in Cairo, 14 linked to patients in Ismailia, one linked to males, and 12 linked to females. LEfSe could not, however, detect any prevalent bacteria among children younger or older than five. Future studies should take advantage of such correlations, specifically BMI, to determine the interventions needed for obesity management.

A Multi-Omics Approach to Disclose Metabolic Pathways Impacting Intestinal Permeability in Obese Patients Undergoing Very Low Calorie Ketogenic Diet

A very low calorie ketogenic diet (VLCKD) impacts host metabolism in people marked by an excess of visceral adiposity, and it affects the microbiota composition in terms of taxa presence and relative abundances. As a matter of fact, there is little available literature dealing with microbiota differences in obese patients marked by altered intestinal permeability. With the aim of inspecting consortium members and their related metabolic pathways, we inspected the microbial community profile, together with the set of volatile organic compounds (VOCs) from untargeted fecal and urine metabolomics, in a cohort made of obese patients, stratified based on both normal and altered intestinal permeability, before and after VLCKD administration. Based on the taxa relative abundances, we predicted microbiota-derived metabolic pathways whose variations were explained in light of our cohort symptom picture. A totally different number of statistically significant pathways marked samples with altered permeability, reflecting an important shift in microbiota taxa. A combined analysis of taxa, metabolic pathways, and metabolomic compounds delineates a set of markers that is useful in describing obesity dysfunctions and comorbidities.

The Effects of Almond Consumption on Cardiovascular Health and Gut Microbiome: A Comprehensive Review

The consumption of almonds has been associated with several health benefits, particularly concerning cardiovascular and intestinal health. In this comprehensive review, we compile and deliberate studies investigating the effects of almond consumption on cardiovascular disease (CVD) risk factors and gut health. Almonds are rich in monounsaturated fats, fiber, vitamins, minerals, and polyphenols, which contribute to their health-promoting properties. Regular intake of almonds has been shown to improve lipid profiles by reducing LDL cholesterol and enhancing HDL functionality. Additionally, almonds aid in glycemic control, blood pressure reduction, and chronic inflammation amelioration, which are critical for cardiovascular health. The antioxidant properties of almonds, primarily due to their high vitamin E content, help in reducing oxidative stress markers. Furthermore, almonds positively influence body composition by reducing body fat percentage and central adiposity and enhancing satiety, thus aiding in weight management. Herein, we also contemplate the emerging concept of the gut-heart axis, where almond consumption appears to modulate the gut microbiome, promoting the growth of beneficial bacteria and increasing short-chain fatty acid production, particularly butyrate. These effects collectively contribute to the anti-inflammatory and cardioprotective benefits of almonds. By encompassing these diverse aspects, we eventually provide a systematic and updated perspective on the multifaceted benefits of almond consumption for cardiovascular health and gut microbiome, corroborating their broader consideration in dietary guidelines and public health recommendations for CVD risk reduction.

Unraveling the gut microbiota of Mexican pinnipeds: the dominance of life histories over phylogeny

Studying how phylogeny influences the composition and functions of microbiotas within animal hosts is essential for gaining insights into the connection between genetics, ecology, and health in the animal kingdom. However, due to limited comprehensive studies, this influence remains unclear for many wild mammals, including Mexican pinnipeds. We employed 16S rRNA gene deep-sequencing to investigate the impact of phylogeny on the gut microbiota of four pinniped species inhabiting Mexican shores: the Pacific harbor seal (Phoca vitulina richardii), the northern elephant seal (Mirounga angustirostris), the California sea lion (Zalophus californianus), and the Guadalupe fur seal (Arctocephalus philippii townsendi). Our results indicated that factors such as diets and shared life histories exerted more influence on microbiota composition than phylogeny alone. Notably, otariid species sharing similar life histories displayed greater microbiota similarity than phocids, which have distinct life histories and fewer microbiota similarities. Furthermore, harbor seals have more microbial similarities with the two otariid species than with elephant seals. Of particular concern, we observed a higher abundance of potentially pathogenic bacteria (e.g., Photobacterium damselae and Clostridium perfringens) in harbor seals and Guadalupe fur seals compared to other pinnipeds. This finding could pose health threats to these species and nearby human populations.IMPORTANCEPinnipeds in Mexico host microbial communities that remain understudied. While several factors can influence microbiota composition, the role of phylogenetic relationships among these pinnipeds remains unclear due to limited knowledge of the microbiota in certain species. This study aimed to fill this gap by characterizing the composition and function of the gut microbiota in the four pinniped species that occur in Mexico. Our analysis reveals that shared diets and life histories contribute to similarities in the composition of gut microbial communities. This study also highlights the potential differences in the metabolic capabilities and adaptations within the gut microbiota of pinnipeds. Understanding how phylogeny impacts microbial communities enhances our insights into the evolutionary dynamics of marine mammals.

1-Deoxynojirimycin containing Morus alba leaf-based food modulates the gut microbiome and expression of genes related to obesity

BACKGROUND

Obesity is a serious disease with an alarmingly high incidence that can lead to other complications in both humans and dogs. Similar to humans, obesity can cause metabolic diseases such as diabetes in dogs. Natural products may be the preferred intervention for metabolic diseases such as obesity. The compound 1-deoxynojirimycin, present in Morus leaves and other sources has antiobesity effects. The possible antiobesity effect of 1-deoxynojirimycin containing Morus alba leaf-based food was studied in healthy companion dogs (n = 46) visiting the veterinary clinic without a history of diseases. Body weight, body condition score (BCS), blood-related parameters, and other vital parameters of the dogs were studied. Whole-transcriptome of blood and gut microbiome analysis was also carried out to investigate the possible mechanisms of action and role of changes in the gut microbiome due to treatment.

RESULTS

After 90 days of treatment, a significant antiobesity effect of the treatment food was observed through the reduction of weight, BCS, and blood-related parameters. A whole-transcriptome study revealed differentially expressed target genes important in obesity and diabetes-related pathways such as MLXIPL, CREB3L1, EGR1, ACTA2, SERPINE1, NOTCH3, and CXCL8. Gut microbiome analysis also revealed a significant difference in alpha and beta-diversity parameters in the treatment group. Similarly, the microbiota known for their health-promoting effects such as Lactobacillus ruminis, and Weissella hellenica were abundant (increased) in the treatment group. The predicted functional pathways related to obesity were also differentially abundant between groups.

CONCLUSIONS

1-Deoxynojirimycin-containing treatment food have been shown to significantly improve obesity. The identified genes, pathways, and gut microbiome-related results may be pursued in further studies to develop 1-deoxynojirimycin-based products as candidates against obesity.

Shotgun metagenomics reveals the gut microbial diversity and functions in Vespa mandarinia (Hymenoptera: Vespidae) at multiple life stages

Wasps play important roles as predators and pollinators in the ecosystem. The Jingpo minority residing in Yunnan Province, China, has a traditional practice of using wine infused with mature wasps as a customary remedy for managing rheumatoid arthritis. The larva of the wasp is also a tasteful folk dish that has created a tremendous market. There is a paucity of survival knowledge, which has greatly restricted their potential applications in food and healthcare. Recent research has highlighted the importance of gut microbiota in insect growth. Nevertheless, there is still a lack of understanding regarding the composition, changes, and functions of the gut microbiota in Vespa mandarinia during development. In this research, the gut microbiota were investigated across three growth stages of Vespa mandarinia using a metagenomic technology. The result revealed that there are significant variations in the proportion of main gut microbes during the metamorphosis of Vespa mandarinia. Tenericutes were found to dominate during the larval stage, while Proteobacteria emerged as the dominant group post-pupation. Through a comprehensive analysis of the gut microbiota metagenome, this study revealed functional differences in the wasp gut microbiota at various growth stages. During the larval stage, the gut microbiota plays a central role in promoting metabolism. Following pupation, the gut microbiota exhibited diversified functions, likely due to the complex environments and diverse food sources encountered after metamorphosis. These functions included amino acid metabolism, compound degradation, and defense mechanisms. This research provides an extensive dataset on the gut microbiota during the metamorphosis of Vespa mandarinia, contributing to a deeper understanding of the influence of gut microbiota on wasp growth. Furthermore, this study uncovers a unique microbial treasure within insect guts, which is important for advancing the application of wasps in the fields of food and medicine.

Association between LEPR Genotype and Gut Microbiome in Healthy Non-Obese Korean Adults

The LEPR (leptin receptor) genotype is associated with obesity. Gut microbiome composition differs between obese and non-obese adults. However, the impact of LEPR genotype on gut microbiome composition in humans has not yet been studied. In this study, the association between LEPR single nucleotide polymorphism (rs1173100, rs1137101, and rs790419) and the gut microbiome composition in 65 non-obese Korean adults was investigated. Leptin, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels were also measured in all participants. Mean ± SD (standard deviation) of age, body mass index, and leptin hormone levels of participants was 35.2 ± 8.1 years, 21.4 ± 1.8 kg/m2, and 7989.1 ± 6687.4 pg/mL, respectively. Gut microbiome analysis was performed at the phylum level by 16S rRNA sequencing. Among the 11 phyla detected, only one showed significantly different relative abundances between LEPR genotypes. The relative abundance of Candidatus Saccharibacteria was higher in the G/A genotype group than in the G/G genotype group for the rs1137101 single nucleotide polymorphism (p=0.0322). Participant characteristics, including body mass index, leptin levels, and other lipid levels, were similar between the rs1137101 G/G and G/A genotypes. In addition, the relative abundances of Fusobacteria and Tenericutes showed significant positive relationship with plasma leptin concentrations (p=0.0036 and p=0.0000, respectively). In conclusion, LEPR genotype and gut microbiome may be associated even in normal-weight Korean adults. However, further studies with a greater number of obese adults are needed to confirm whether LEPR genotype is related to gut microbiome composition.

Dietary fiber for the prevention of childhood obesity: a focus on the involvement of the gut microbiota

Given the worldwide epidemic of overweight and obesity among children, evidence-based dietary recommendations are fundamentally important for obesity prevention. Although the significance of the human gut microbiome in shaping the physiological effects of diet and obesity has been widely recognized, nutritional therapeutics for the mitigation of pediatric obesity globally are only just starting to leverage advancements in the nutritional microbiology field. In this review, we extracted data from PubMed, EMBASE, Scopus, Web of Science, Google Scholar, CNKI, Cochrane Library and Wiley online library that focuses on the characterization of gut microbiota (including bacteria, fungi, viruses, and archaea) in children with obesity. We further review host-microbe interactions as mechanisms mediating the physiological effects of dietary fibers and how fibers alter the gut microbiota in children with obesity. Contemporary nutritional recommendations for the prevention of pediatric obesity are also discussed from a gut microbiological perspective. Finally, we propose an experimental framework for integrating gut microbiota into nutritional interventions for children with obesity and provide recommendations for the design of future studies on precision nutrition for pediatric obesity.

Contribution of the microbiome for better phenotyping of people living with obesity

Obesity has reached epidemic proportion worldwide and in all ages. Available evidence points to a multifactorial pathogenesis involving gene predisposition and environmental factors. Gut microbiota plays a critical role as a major interface between external factors, i.e., diet, lifestyle, toxic chemicals, and internal mechanisms regulating energy and metabolic homeostasis, fat production and storage. A shift in microbiota composition is linked with overweight and obesity, with pathogenic mechanisms involving bacterial products and metabolites (mainly endocannabinoid-related mediators, short-chain fatty acids, bile acids, catabolites of tryptophan, lipopolysaccharides) and subsequent alterations in gut barrier, altered metabolic homeostasis, insulin resistance and chronic, low-grade inflammation. Although animal studies point to the links between an "obesogenic" microbiota and the development of different obesity phenotypes, the translational value of these results in humans is still limited by the heterogeneity among studies, the high variation of gut microbiota over time and the lack of robust longitudinal studies adequately considering inter-individual confounders. Nevertheless, available evidence underscores the existence of several genera predisposing to obesity or, conversely, to lean and metabolically health phenotype (e.g., Akkermansia muciniphila, species from genera Faecalibacterium, Alistipes, Roseburia). Further longitudinal studies using metagenomics, transcriptomics, proteomics, and metabolomics with exact characterization of confounders are needed in this field. Results must confirm that distinct genera and specific microbial-derived metabolites represent effective and precision interventions against overweight and obesity in the long-term.

Bayesian compositional regression with microbiome features via variational inference

The microbiome plays a key role in the health of the human body. Interest often lies in finding features of the microbiome, alongside other covariates, which are associated with a phenotype of interest. One important property of microbiome data, which is often overlooked, is its compositionality as it can only provide information about the relative abundance of its constituting components. Typically, these proportions vary by several orders of magnitude in datasets of high dimensions. To address these challenges we develop a Bayesian hierarchical linear log-contrast model which is estimated by mean field Monte-Carlo co-ordinate ascent variational inference (CAVI-MC) and easily scales to high dimensional data. We use novel priors which account for the large differences in scale and constrained parameter space associated with the compositional covariates. A reversible jump Monte Carlo Markov chain guided by the data through univariate approximations of the variational posterior probability of inclusion, with proposal parameters informed by approximating variational densities via auxiliary parameters, is used to estimate intractable marginal expectations. We demonstrate that our proposed Bayesian method performs favourably against existing frequentist state of the art compositional data analysis methods. We then apply the CAVI-MC to the analysis of real data exploring the relationship of the gut microbiome to body mass index.

Characterization of gut microbiota associated with metabolic syndrome and type-2 diabetes mellitus in Mexican pediatric subjects

BACKGROUND

Childhood obesity is a serious public health concern that confers a greater risk of developing important comorbidities such as MetS and T2DM. Recent studies evidence that gut microbiota may be a contributing factor; however, only few studies exist in school-age children. Understanding the potential role of gut microbiota in MetS and T2DM pathophysiology from early stages of life might contribute to innovative gut microbiome-based interventions that may improve public health. The main objective of the present study was to characterize and compare gut bacteria of T2DM and MetS children against control subjects and determine which microorganisms might be potentially related with cardiometabolic risk factors to propose gut microbial biomarkers that characterize these conditions for future development of pre-diagnostic tools.

RESULTS

Stool samples from 21 children with T2DM, 25 with MetS, and 20 controls (n = 66) were collected and processed to conduct 16S rDNA gene sequencing. α- and β-diversity were studied to detect microbial differences among studied groups. Spearman correlation was used to analyze possible associations between gut microbiota and cardiometabolic risk factors, and linear discriminant analyses (LDA) were conducted to determine potential gut bacterial biomarkers. T2DM and MetS showed significant changes in their gut microbiota at genus and family level. Read relative abundance of Faecalibacterium and Oscillospora was significantly higher in MetS and an increasing trend of Prevotella and Dorea was observed from the control group towards T2DM. Positive correlations were found between Prevotella, Dorea, Faecalibacterium, and Lactobacillus with hypertension, abdominal obesity, high glucose levels, and high triglyceride levels. LDA demonstrated the relevance of studying least abundant microbial communities to find specific microbial communities that were characteristic of each studied health condition.

CONCLUSIONS

Gut microbiota was different at family and genus taxonomic levels among controls, MetS, and T2DM study groups within children from 7 to 17 years old, and some communities seemed to be correlated with relevant subjects' metadata. LDA helped to find potential microbial biomarkers, providing new insights regarding pediatric gut microbiota and its possible use in the future development of gut microbiome-based predictive algorithms.

The number of metabolic syndrome risk factors predicts alterations in gut microbiota in Chinese children from the Huantai study

BACKGROUND

Evidence on the effect of gut microbiota on the number of metabolic syndrome (MetS) risk factors among children is scarce. We aimed to examine the alterations of gut microbiota with different numbers of MetS risk factors among children.

METHODS

Data were collected from a nested case-control study at the baseline of the Huantai Childhood Cardiovascular Health Cohort Study in Zibo, China. We compared the differences in gut microbiota based on 16S rRNA gene sequencing among 72 children with different numbers of MetS risk factors matched by age and sex (i.e., none, one, and two-or-more MetS risk factors; 24 children for each group).

RESULTS

The community richness (i.e., the total number of species in the community) and diversity (i.e., the richness and evenness of species in the community) of gut microbiota decreased with an increased number of MetS risk factors in children (P for trend < 0.05). Among genera with a relative abundance greater than 0.01%, the relative abundance of Lachnoclostridium (PFDR = 0.009) increased in the MetS risk groups, whereas Alistipes (PFDR < 0.001) and Lachnospiraceae_NK4A136_group (PFDR = 0.043) decreased in the MetS risk groups compared to the non-risk group. The genus Christensenellaceae_R-7_group excelled at distinguishing one and two-or-more risk groups from the non-risk group (area under the ROC curve [AUC]: 0.84 - 0.92), while the genera Family_XIII_AD3011_group (AUC: 0.73 - 0.91) and Lachnoclostridium (AUC: 0.77 - 0.80) performed moderate abilities in identifying none, one, and two-or-more MetS risk factors in children.

CONCLUSIONS

Based on the nested case-control study and the 16S rRNA gene sequencing technology, we found that dysbiosis of gut microbiota, particularly for the genera Christensenellaceae_R-7_group, Family_XIII_AD3011_group, and Lachnoclostridium may contribute to the early detection and the accumulation of MetS risk factors in childhood.

Association of gut microbiota and glucose metabolism in children with disparate degrees of adiposity

OBJECTIVE

To investigate the characteristics of gut microbiota in children with disparate degrees of adiposity, and analyze the association between gut microbiota, glucose metabolism indicators, and inflammatory factors.

METHODS

Clinical data were examined in 89 Chinese children. Children with a body fat percentage ≥ 30% were diagnosed as obese, and ≥ 35% in males and ≥ 40% in females were further defined as severe obesity. The composition of gut microbiota was determined by 16S rDNA-based metagenomics.

RESULTS

The study population (9.75 ± 1.92-year-old) was characterized as normal weight (n = 29), mild obesity (n = 27) and severe obesity (n = 33) groups. Linear discriminant analysis Effect Size (LEfSe) analysis found that compared to the severe obesity group, subjects with mild obesity had more prevalent members of the phylum Fusobacteria, the genus Alistipes, and fewer members of genus Granulicatella and Clostridium (p < 0.05). For subjects with mild obesity, Spearman's correlation analysis revealed that fasting plasma glucose positively correlated with species A. indistinctus, A. putredinis, and negatively correlated with species Ruminococcus gnavus; LBP negatively correlated with species Clostridium hathewayi, and Blautia producta. For subjects with severe obesity, oral glucose tolerance test 2 h plasma glucose (OGTT2HPG) negatively correlated with the phylum Synergistetes, genus Pyramidobacter, species Veillonella parvula, P. piscolens, and positively correlated with species B. producta, INS and HOMA-IR negatively correlated with the genus Haemophilus, species H. parainfluenzae, lipopolysaccharide-binding protein (LBP) negatively correlated with the phylum Actinobacteria, genus Bifidobacterium, Lactobacillus, and species B. longum (all p < 0.05). Phylogenetic investigation of communities by reconstruction of unobserved states 2 (PICRUSt2) analysis discerned that the glucose metabolism pathway, gluconeogenesis I was curtailed in the severe obesity group.

CONCLUSION

The gut microbiota could favourably compensate for glucose metabolism in children with obesity. Genus Haemophilus and Bifidobacterium longum may influence glucose tolerance and insulin resistance in children with severe obesity.

The diet rapidly and differentially affects the gut microbiota and host lipid mediators in a healthy population

BACKGROUND

Bioactive lipids produced by human cells or by the gut microbiota might play an important role in health and disease. Dietary intakes are key determinants of the gut microbiota, its production of short-chain (SCFAs) and branched-chain fatty acids (BCFAs), and of the host endocannabinoidome signalling, which are all involved in metabolic diseases. This hypothesis-driven longitudinal fixed sequence nutritional study, realized in healthy participants, was designed to determine if a lead-in diet affects the host response to a short-term dietary intervention. Participants received a Mediterranean diet (MedDiet) for 3 days, a 13-day lead-in controlled diet reflecting the average Canadian dietary intake (CanDiet), and once again a MedDiet for 3 consecutive days. Fecal and blood samples were collected at the end of each dietary phase to evaluate alterations in gut microbiota composition and plasma levels of endocannabinoidome mediators, SCFAs, and BCFAs.

RESULTS

We observed an immediate and reversible modulation of plasma endocannabinoidome mediators, BCFAs, and some SCFAs in response to both diets. BCFAs were more strongly reduced by the MedDiet when the latter was preceded by the lead-in CanDiet. The gut microbiota response was also immediate, but not all changes due to the CanDiet were reversible following a short dietary MedDiet intervention. Higher initial microbiome diversity was associated with reduced microbiota modulation after short-term dietary interventions. We also observed that BCFAs and 2-monoacylglycerols had many, but distinct, correlations with gut microbiota composition. Several taxa modulated by dietary intervention were previously associated to metabolic disorders, warranting the need to control for recent diet in observational association studies.

CONCLUSIONS

Our results indicate that lipid mediators involved in the communication between the gut microbiota and host metabolism exhibit a rapid response to dietary changes, which is also the case for some, but not all, microbiome taxa. The lead-in diet influenced the gut microbiome and BCFA, but not the endocannabinoidome, response to the MedDiet. A higher initial microbiome diversity favored the stability of the gut microbiota in response to dietary changes. This study highlights the importance of considering the previous diet in studies relating the gut microbiome with lipid signals involved in host metabolism. Video Abstract.

Bioactive compounds in childhood obesity and associated metabolic complications: Current evidence, controversies and perspectives

Obesity represents the most frequent chronic disease among children worldwide, with a significant global burden on society. Metabolically unhealthy obesity (MUO) can affect children since their first years of life, and novel therapeutic strategies to tackle metabolic complications are under investigation. This review focuses on bioactive compounds and their possible beneficial effects on obesity, particularly omega-3, docosahexaenoic acid, vitamin D, biotics, polysaccharide macromolecules, polyphenols, inositols, alpha lipoic acid, and bromelaine. Our aim is to summarize current evidence about bioactive compounds in the treatment of obesity, highlighting recent findings on their use in children and adolescents. Most studied molecules are omega-3 and vitamin D, despite the heterogeneity between the studies. Moreover, given the emerging interest in the gut-brain axis in the link between metabolic health and microbiota, various studies on prebiotics, probiotics, synbiotics, postbiotics and polysaccharide macromolecules have been considered. Some preclinical studies seem to highlight a possible role of the polyphenols, even if their clinical evidence is still discussed. Lastly, we describe possible effects of inositols and alpha-lipoic acid. Despite some dietary supplements seem to be promising in overweight subjects, only in a few of them a dose/response efficacy has been found in the pediatric age. Innovative, well-designed and targeted clinical trials are then needed to prove the beneficial effects of these compounds that could support the standard behavioral therapy for obesity.

Causal associations between gut microbiota and adverse pregnancy outcomes: A two-sample Mendelian randomization study

Growing evidence indicates that gut microbiota could be closely associated with a variety of adverse pregnancy outcomes (APOs), but a causal link between gut microbiome and APOs has yet to be established. Therefore, in this study, we comprehensively investigated the relationship between gut microbiota and APOs to identify specific causal bacteria that may be associated with the development and occurrence of APOs by conducting a two-sample Mendelian randomization (MR) analysis. The microbiome genome-wide association study (GWAS) from the MiBioGen consortium was used as exposure data, and the GWAS for six common APOs was used as outcome data. Single-nucleotide polymorphisms (SNPs) that significantly correlated to exposure, data obtained from published GWAS, were selected as instrumental variables (IVs). We used the inverse variance-weighted (IVW) test as the main MR analysis to estimate the causal relationship. The Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) and MR-Egger regression were used to confirm the presence of horizontal pleiotropy and to exclude outlier SNPs. We performed Cochran's Q test to assess the heterogeneity among SNPs associated with each bacterium. The leave-one-out sensitivity analysis was used to evaluate whether the overall estimates were affected by a single SNP. Our analysis shows a causal association between specific gut microbiota and APOs. Our findings offer novel insights into the gut microbiota-mediated development mechanism of APOs.

Gut microbiota in obesity and related comorbidities in children and adolescents: the role of biotics in treatment

INTRODUCTION

Obesity is a complex pathology, globally spread, with a multifactorial pathogenesis, strictly linked with lifestyle, hormones, genetic and epigenetic factors. Evidence supports that obesity, and its comorbidities, are related to changes in gut microbiota, partially responsible of the modulation of energy metabolism.

EVIDENCE ACQUISITION

Pediatric obesity has been associated with lower bacterial diversity and differences in composition of the gut microbiota, also varying according to the metabolic status of obese subjects. Indeed, differences in distributions and activity of microorganisms in the gut of metabolically healthy and unhealthy obese children have been highlighted.

EVIDENCE SYNTHESIS

Based on human studies, this review aims to discuss gut microbiota alterations in obese children and adolescents and its role in obese-related complications. Moreover, the role of biotics (probiotics, prebiotics, synbiotics and -marginally- postbiotics) has been analyzed as modulator of obesity-related dysbiosis.

CONCLUSIONS

As a conclusion, a deeper knowledge about biotic mechanisms of action would be of great interest to implement the clinical care of children and adolescents with obesity and related comorbidities.

Effects of Dietary Supplementation of Solubles from Shredded, Steam-Exploded Pine Particles on the Performance and Cecum Microbiota of Acute Heat-Stressed Broilers

Heat stress (HS) negatively influences livestock productivity, but it can be, at least in part, mitigated by nutritional interventions. One such intervention is to use byproducts from various sources that are likely to be included in the consumer chain. Thus, the present study investigated the effects of dietary supplementation of solubles from shredded, steam-exploded pine particles (SSPPs) on the performance and cecum microbiota in broilers subjected to acute HS. One-week-old Ross 308 broilers (n = 108) were fed 0%, 0.1%, or 0.4% SSPP in their diets. On the 37th day, forty birds were allocated to one of four groups; namely, a group fed a control diet without SSPPs at thermoneutral temperature (NT) (0% NT) and acute heat-stressed birds with 0% (0% HS), 0.1% (0.1% HS), and 0.4% (0.4% HS) SSPP-supplemented diets. The NT was maintained at 21.0 °C, while the HS room was increased to 31 °C. The final BW, percent difference in body weight (PDBW), and feed intake (FI) were lower in HS birds, but PDBW was reversely associated with dietary SSPP. Similarly, HS birds had a higher rectal temperature (RT) and ΔT in comparison to birds kept at NT. The FI of SSPP-supplemented birds was not significant, indicating lower HS effects. Plasma triglyceride was decreased in HS birds but not affected in 0.1% HS birds in comparison to 0% NT birds. OTUs and Chao1 were increased by 0.1% HS compared to 0% NT. Unweighted Unifrac distances for 0.1% HS were different from 0% NT and 0.4% HS. The favorable bacterial phylum (Tenericutes) and genera (Faecalibacterium and Anaerofustis) were increased, while the pathogenic genus (Enterococcus) was decreased, in SSPP-supplemented birds. In sum, production performances are negatively affected under acute HS. Dietary supplementation of SSPPs is beneficial for improving community richness indices and unweighted Unifrac distances, and it enhanced the advantageous bacterial phyla and reduced virulent genera and triglyceride hydrolysis in acute HS broilers. Our results indicate that dietary SSPPs modulates the microbial profile of the cecum while resulting in relatively less weight loss and lower rectal temperature compared to control.

The double-edged sword of probiotic supplementation on gut microbiota structure in Helicobacter pylori management

As Helicobacter pylori management has become more challenging and less efficient over the last decade, the interest in innovative interventions is growing by the day. Probiotic co-supplementation to antibiotic therapies is reported in several studies, presenting a moderate reduction in drug-related side effects and a promotion in positive treatment outcomes. However, the significance of gut microbiota involvement in the competence of probiotic co-supplementation is emphasized by a few researchers, indicating the alteration in the host gastrointestinal microbiota following probiotic and drug uptake. Due to the lack of long-term follow-up studies to determine the efficiency of probiotic intervention in H. pylori eradication, and the delicate interaction of the gut microbiota with the host wellness, this review aims to discuss the gut microbiota alteration by probiotic co-supplementation in H. pylori management to predict the comprehensive effectiveness of probiotic oral administration.Abbreviations: acyl-CoA- acyl-coenzyme A; AMP- antimicrobial peptide; AMPK- AMP-activated protein kinase; AP-1- activator protein 1; BA- bile acid; BAR- bile acid receptor; BCAA- branched-chain amino acid; C2- acetate; C3- propionate; C4- butyrate; C5- valeric acid; CagA- Cytotoxin-associated gene A; cAMP- cyclic adenosine monophosphate; CD- Crohn's disease; CDI- C. difficile infection; COX-2- cyclooxygenase-2; DC- dendritic cell; EMT- epithelial-mesenchymal transition; FMO- flavin monooxygenases; FXR- farnesoid X receptor; GPBAR1- G-protein-coupled bile acid receptor 1; GPR4- G protein-coupled receptor 4; H2O2- hydrogen peroxide; HCC- hepatocellular carcinoma; HSC- hepatic stellate cell; IBD- inflammatory bowel disease; IBS- irritable bowel syndrome; IFN-γ- interferon-gamma; IgA immunoglobulin A; IL- interleukin; iNOS- induced nitric oxide synthase; JAK1- janus kinase 1; JAM-A- junctional adhesion molecule A; LAB- lactic acid bacteria; LPS- lipopolysaccharide; MALT- mucosa-associated lymphoid tissue; MAMP- microbe-associated molecular pattern; MCP-1- monocyte chemoattractant protein-1; MDR- multiple drug resistance; mTOR- mammalian target of rapamycin; MUC- mucin; NAFLD- nonalcoholic fatty liver disease; NF-κB- nuclear factor kappa B; NK- natural killer; NLRP3- NLR family pyrin domain containing 3; NOC- N-nitroso compounds; NOD- nucleotide-binding oligomerization domain; PICRUSt- phylogenetic investigation of communities by reconstruction of unobserved states; PRR- pattern recognition receptor; RA- retinoic acid; RNS- reactive nitrogen species; ROS- reactive oxygen species; rRNA- ribosomal RNA; SCFA- short-chain fatty acids; SDR- single drug resistance; SIgA- secretory immunoglobulin A; STAT3- signal transducer and activator of transcription 3; T1D- type 1 diabetes; T2D- type 2 diabetes; Th17- T helper 17; TLR- toll-like receptor; TMAO- trimethylamine N-oxide; TML- trimethyllysine; TNF-α- tumor necrosis factor-alpha; Tr1- type 1 regulatory T cell; Treg- regulatory T cell; UC- ulcerative colitis; VacA- Vacuolating toxin A.

Gut microbiota and COVID-19: An intriguing pediatric perspective

Gastrointestinal (GI) involvement has been reported in approximately 50% of patients with coronavirus disease 2019 (COVID-19), which is due to the pathogenic role of inflammation and the intestinal function of the angiotensin-converting enzyme 2 and its receptor. Accumulating adult data has pointed out that gut dysbiosis might occur in these patients with a potential impact on the severity of the disease, however the role of gut microbiota in susceptibility and severity of COVID-19 disease in children is still poorly known. During the last decades, the crosstalk between gut and lung has been largely recognized resulting in the concept of “gut-lung axis” as a central player in modulating the development of several diseases. Both organs are involved in the common mucosal immune system (including bronchus-associated and gut-associated lymphoid tissues) and their homeostasis is crucial for human health. In this framework, it has been found that the role of GI dysbiosis is affecting the homeostasis of the gut-liver axis. Of note, a gut microbiome imbalance has been linked to COVID-19 severity in adult subjects, but it remains to be clarified. Based on the increased risk of inflammatory diseases in children with COVID-19, the potential correlation between gut microbiota dysfunction and COVID-19 needs to be studied in this population. We aimed to summarize the most recent evidence on this striking aspect of COVID-19 in childhood.

Reduced gut microbial diversity in familial hypercholesterolemia with no effect of omega-3 polyunsaturated fatty acids intervention - a pilot trial

Individuals with familial hypercholesterolemia (FH) undergo an aggressive treatment with cholesterol-lowering drugs to prevent coronary heart disease. Recent evidence suggests an interplay between the gut microbiota, blood lipid levels and lipid-lowering drugs, but this has yet to be studied in individuals with FH. The objective of the study was to characterize the gut microbiota of individuals with familial hypercholesterolemia and examine if effects of omega-3 polyunsaturated fatty acids (PUFAs) on blood lipids act through modification of the gut microbiome. The gut microbiota composition of individuals with FH (N = 21) and healthy controls (N = 144) was analyzed by extracting DNA from stool samples and sequencing of the V3-V4 region of the 16S rRNA gene. A subgroup (n = 15) of the participants received omega-3 polyunsaturated fatty acids (PUFAs) supplementation or placebo in a crossover manner, and the effect of PUFAs on the gut microbiota was also investigated. Individuals with FH had a different gut microbiota composition compared to healthy controls, characterized by reduced richness (p = .001) and reduction of several genera belonging to Clostridia and Coriobacteriia. Patients using ezetimibe in addition to statins appeared to have lower richness compared to those only using statins (p = .01). Intervention with omega-3 PUFAs had negligible impact on the microbiota composition. Positive effects on blood lipids after intervention with omega-3 PUFA were not associated with baseline gut microbiota composition or gut microbial changes during treatment. Further, patients with FH have an altered gut microbiota compared to healthy controls, possibly driven by the use of ezetimibe.

A Possible Link between Gut Microbiome Composition and Cardiovascular Comorbidities in Psoriatic Patients

Cardiovascular disease (CVD) is one of the most common comorbidities that may affect psoriatic patients. Several exogenous and endogenous factors are involved in the etiology and progression of both psoriasis and CVD. A potential genetic link between the two diseases has emerged; however, some gaps remain in the understanding of the CVD prevalence in psoriatic patients. Recently, the role of the gut microbiome dysbiosis was documented in the development and maintenance of both diseases. To investigate whether gut microbiome dysbiosis might influence the occurrence of CVD in psoriatic patients, 16S rRNA gene sequencing was performed to characterize the gut microbiome of 28 psoriatic patients, including 17 patients with and 11 without CVD. The comparison of the gut microbiome composition between patients with and without CVD showed a higher prevalence of Barnesiellaceae and Phascolarctobacterium in patients with CVD. Among patients with CVD, those undergoing biologic therapy had lower abundance levels of Barnesiellaceae, comparable to those found in patients without CVD. Overall, these findings suggest that the co-occurrence of psoriasis and CVD might be linked to gut microbiome dysbiosis and that therapeutic strategies could help to restore the intestinal symbiosis, potentially improving the clinical management of psoriasis and its associated comorbidities.

Composition of Human Breast Milk Microbiota and Its Role in Children's Health

Human milk contains a number of nutritional and bioactive molecules including microorganisms that constitute the so-called "Human Milk Microbiota (HMM)". Recent studies have shown that not only bacterial but also viral, fungal, and archaeal components are present in the HMM. Previous research has established, a "core" microbiome, consisting of Firmicutes (i.e., Streptococcus, Staphylococcus), Proteobacteria (i.e., Serratia, Pseudomonas, Ralstonia, Sphingomonas, Bradyrhizobium), and Actinobacteria (i.e., Propionibacterium, Corynebacterium). This review aims to summarize the main characteristics of HMM and the role it plays in shaping a child's health. We reviewed the most recent literature on the topic (2019-2021), using the PubMed database. The main sources of HMM origin were identified as the retrograde flow and the entero-mammary pathway. Several factors can influence its composition, such as maternal body mass index and diet, use of antibiotics, time and type of delivery, and mode of breastfeeding. The COVID-19 pandemic, by altering the mother-infant dyad and modifying many of our previous habits, has emerged as a new risk factor for the modification of HMM. HMM is an important contributor to gastrointestinal colonization in children and therefore, it is fundamental to avoid any form of perturbation in the HMM that can alter the microbial equilibrium, especially in the first 100 days of life. Microbial dysbiosis can be a trigger point for the development of necrotizing enterocolitis, especially in preterm infants, and for onset of chronic diseases, such as asthma and obesity, later in life.

Gut microbiota in patients with obesity and metabolic disorders - a systematic review

BACKGROUND

Previous observational studies have demonstrated inconsistent and inconclusive results of changes in the intestinal microbiota in patients with obesity and metabolic disorders. We performed a systematic review to explore evidence for this association across different geography and populations.

METHODS

We performed a systematic search of MEDLINE (OvidSP) and Embase (OvidSP) of articles published from Sept 1, 2010, to July 10, 2021, for case-control studies comparing intestinal microbiome of individuals with obesity and metabolic disorders with the microbiome of non-obese, metabolically healthy individuals (controls). The primary outcome was bacterial taxonomic changes in patients with obesity and metabolic disorders as compared to controls. Taxa were defined as "lean-associated" if they were depleted in patients with obesity and metabolic disorders or negatively associated with abnormal metabolic parameters. Taxa were defined as "obesity-associated" if they were enriched in patients with obesity and metabolic disorders or positively associated with abnormal metabolic parameters.

RESULTS

Among 2390 reports screened, we identified 110 full-text articles and 60 studies were included. Proteobacteria was the most consistently reported obesity-associated phylum. Thirteen, nine, and ten studies, respectively, reported Faecalibacterium, Akkermansia, and Alistipes as lean-associated genera. Prevotella and Ruminococcus were obesity-associated genera in studies from the West but lean-associated in the East. Roseburia and Bifidobacterium were lean-associated genera only in the East, whereas Lactobacillus was an obesity-associated genus in the West.

CONCLUSIONS

We identified specific bacteria associated with obesity and metabolic disorders in western and eastern populations. Mechanistic studies are required to determine whether these microbes are a cause or product of obesity and metabolic disorders.

Fecal microbiota relationships with childhood obesity: A scoping comprehensive review

Childhood obesity is a costly burden in most regions with relevant and adverse long-term health consequences in adult life. Several studies have associated excessive body weight with a specific profile of gut microbiota. Different factors related to fecal microorganism abundance seem to contribute to childhood obesity, such as gestational weight gain, perinatal diet, antibiotic administration to the mother and/or child, birth delivery, and feeding patterns, among others. This review reports and discusses diverse factors that affect the infant intestinal microbiota with putative or possible implications on the increase of the obesity childhood rates as well as microbiota shifts associated with excessive body weight in children.

A powerful adaptive microbiome-based association test for microbial association signals with diverse sparsity levels

The dysbiosis of microbiome may have negative effects on a host phenotype. The microbes related to the host phenotype are regarded as microbial association signals. Recently, statistical methods based on microbiome-phenotype association tests have been extensively developed to detect these association signals. However, the currently available methods do not perform well to detect microbial association signals when dealing with diverse sparsity levels (i.e., sparse, low sparse, non-sparse). Actually, the real association patterns related to different host phenotypes are not unique. Here, we propose a powerful and adaptive microbiome-based association test to detect microbial association signals with diverse sparsity levels, designated as MiATDS. In particular, we define probability degree to measure the associations between microbes and the host phenotype and introduce the adaptive weighted sum of powered score tests by considering both probability degree and phylogenetic information. We design numerous simulation experiments for the task of detecting association signals with diverse sparsity levels to prove the performance of the method. We find that type I error rates can be well-controlled and MiATDS shows superior efficiency on the power. By applying to real data analysis, MiATDS displays reliable practicability too. The R package is available at https://github.com/XiaoyunHuang33/MiATDS.

Gut dsDNA virome shows diversity and richness alterations associated with childhood obesity and metabolic syndrome

Changes in the human gut microbiome are associated with obesity and metabolic syndrome, but the role of the gut virome in both diseases remains largely unknown. We characterized the gut dsDNA virome of 28 school-aged children with healthy normal-weight (NW, n = 10), obesity (O, n = 10), and obesity with metabolic syndrome (OMS, n = 8), using metagenomic sequencing of virus-like particles (VLPs) from fecal samples. The virome classification confirmed the bacteriophages' dominance, mainly composed of Caudovirales. Notably, phage richness and diversity of individuals with O and OMS tended to increase, while the VLP abundance remained the same among all groups. Of the 4,611 phage contigs composing the phageome, 48 contigs were highly prevalent in ≥80% of individuals, suggesting high inter-individual phage diversity. The abundance of several contigs correlated with gut bacterial taxa; and with anthropometric and biochemical parameters altered in O and OMS. To our knowledge, this gut phageome represents one of the largest datasets and suggests disease-specific phage alterations.