Gut bacterial microbiota and obesity

Diet- and sex-related changes of gut microbiota composition and functional profiles after 4 months of weight loss intervention

PURPOSE

Obesity has been related to intestinal dysbiosis and the modification of gut microbiota composition by dietary strategies becomes a promising strategy to help manage obesity. The aim of the current study was to evaluate the effect of two weight-loss diets on the composition and functional profile of gut microbiota.

METHODS

55 men and 124 women with BMI > 25 kg/m² were randomly assigned to moderately high-protein (MHP) or low-fat (LF) diet. Differences in fecal bacteria abundance (based on 16 s rRNA sequencing) between before and after 4 months of calorie restriction was analyzed using EdgeR tool in MicrobiomeAnalyst platform. Bacterial functional profile was predicted using Tax4Fun and metagenomeSeq analysis. Significant KEGG Orthology (KO) terms were selected for the metabolomic study using chromatography.

RESULTS

After the intervention, MHP-men showed a significant decrease in Negativicutes, Selenomonadales, Dielma and Dielma fastidiosa. LF-men showed a significant increase in Bacilli, Lactobacillales, Christensenellaceae, Peptococcaceae, and Streptococcaceae, Peptococcus, Streptococcus and Christensenella, Duncaniella dubosii_CP039396_93.49%, Roseburia sp_AB744234_98.96% and Alistipes inops_KJ572413_99.57%. MHP-women increased Pasteurellales, Phascolarctobacterium succinatutens, Ruthenibacterium lactatiformans_LR215981_99.55% and decreased in Phascolarctobacterium succinatutens_NR112902_99.56%. Finally, LF-women presented a significant decrease in Bacteroides clarus and Erysipelothrix inopinata_CP060715_84.4%. Surprisingly, no matching bacterial changes were found between these four groups. A total of 42 KO, 10 metabolic pathways and 107 related metabolites related were found implicated in these bacterial changes. Seven metabolites were confirmed in plasma.

CONCLUSION

Weight-loss-related-changes in gut microbiome composition and the functional profile occur in a sex- and diet-related manner, showing that women and men could differentially benefit from the consumption of MHP and LF diets.

TRIAL REGISTRATION

NCT02737267, 10th March 2016 retrospectively registered.

A pilot study on the relationship between Lactobacillus, Bifidibactrium counts and inflammatory factors following exercise training

BACKGROUND

The current pilot study was carried out to examine the effect of aerobic exercise on Lactobacillus and Bifidobacterium as a function of weight loss and cytokine changes in overweight women.

MATERIAL AND METHODS

Eighteen women with excessive weight (age = 19-30 years) were randomly assigned into exercise (10 weeks, aerobic exercise training, 3 sessions/week) and control groups. Lactobacillus and Bifidobacterium in stool and inflammatory factors in blood were evaluated before and after the intervention.

RESULTS

The intervention induced significant improvements in body weight and in V_O2 peak. There were significant time effects on Lactobacillus (p = .016) and significant time*exercise interaction effects on Bifidobacterium (p = .025). Lactobacillus and Bifidobacterium changes were negatively associated with body weight and IL-6 levels, respectively.

CONCLUSIONS

The current results indicate that exercise training associated with weight loss can increase specific bacteria in people with excessive weight. Changes in Lactobacillus and Bifidobacterium were not significantly associated with cytokines.

Modulation of the Gut Microbiota by Shen-Yan-Fang-Shuai Formula Improves Obesity Induced by High-Fat Diets

Obesity and related metabolic disorders are associated with intestinal microbiota dysbiosis, disrupted intestinal barrier and chronic inflammation. Shen-Yan-Fang-Shuai formula (SYFSF) is a traditional Chinese herbal formula composed of Astragali Radix, Radix Angelicae Sinensis, Rheum Officinale Baill, and four other herbs. In this study, we identified that SYFSF treatment prevented weight gain, low-grade inflammation and insulin resistance in high-fat diet (HFD)-fed mice. SYFSF also substantially improved gut barrier function, reduced metabolic endotoxemia, as well as systemic inflammation. Sequencing of 16S rRNA genes obtained from fecal samples demonstrated that SYFSF attenuated HFD-induced gut dysbiosis, seen an decreased Firmicutes to Bacteroidetes ratios. Microbial richness and diversity were also higher in the SYFSF-treated HFD group. Furthermore, similar therapeutic effects and changes in gut microbiota profile caused by SYFSF could be replicated by fecal microbiota transfer (FMT). Taken together, our study highlights the efficacy of SYFSF in preventing obesity and related metabolic disorders. Its therapeutic effect is associated with the modulation of gut microbiota, as a prebiotic.

Microcystis toxin-mediated tumor promotion and toxicity lead to shifts in mouse gut microbiome

Microcystins (MCs) are the most prevalent cyanotoxins reported in freshwater. While numerous studies have examined the toxicological impacts of MCs on mammalian systems, very few have examined the chronic impacts of MCs on the gut microbiome of exposed organisms. Our understanding of the relationship of MCs, especially lysed toxic cyanobacteria, and the gut microbiota is very limited. The objective of this study was to determine the impacts of MC-LR and Microcystis lysate ingestion on the gut microbiome in a hepatocellular carcinoma mouse model, simulating a high-risk population and exposure at an environmentally relevant MC level. Mice were assigned to 4 groups (MC-LR; Microcystis lysate; Negative control; Positive (liver carcinogen) control). Fecal samples were collected every 8 weeks. Bacterial community and colony counts were analyzed. The abundance of Firmicutes in the positive control and lysate group was higher than the negative control and MC group. Exposure to MC-LR or lysate was associated with significantly decreased bacterial diversity. A distinct separation of the three groups (MC-LR/lysate/carcinogen) from the negative was much more apparent in their gut microbiome as the exposure time increased. The MC-LR and lysate groups showed gut microbiome structure responding to lipid metabolism disturbance and high stress. Bacterial colony count was significantly lower in all the treated groups than the negative control. Our study highlights that chronic exposure to MC-LR and Microcystis lysate negatively impacts gut microbiome succession and altered the bacterial community structure into the one similar to the carcinogen group, which may indicate that the change favors progression of hepatocellular carcinoma. In a future study, more in-depth investigation is warranted to better understand the liver-gut nexus in promoting liver cancer among those exposed to MC and toxic cyanobacteria.

California strawberry consumption increased the abundance of gut microorganisms related to lean body weight, health and longevity in healthy subjects

It was our hypothesis that foods high in polyphenols and fiber have prebiotic activity. This human intervention study aimed to determine if daily consumption of freeze-dried California strawberry powder (SBP) leads to changes in the intestinal microbiota, fecal cholesterol and bile acid (BA) microbial metabolites. Fifteen healthy adults consumed a beige diet+26 g of SBP for 4 weeks, followed by 2 weeks of beige diet only. Stool samples were collected at 0, 4, and 6 weeks. Fecal microbiota was analyzed by 16S rRNA sequencing; fecal cholesterol, BA, and microbial metabolites by gas chromatography. Confirming compliance, urine concentration of pelargonidin, urolithin A glucuronide and dimethylellagic acid glucuronide were present after 4 weeks of SBP consumption. Daily SBP altered the abundance of 24 operational taxonomic units (OTUs). Comparing week 4 to baseline the most significant increases were observed for one OTU from Firmicutes\Clostridia\ Christensenellaceae\NA, one OTU from Firmicutes\ Clostridia\Mogibacteriacea\NA, one OTU from Verrucomicrobia\ Verrucomicrobiaceae\Akkermansia\Muciniphila, one OTU from Actinobacteria\ Bifidobacteriaceae\Bifidobacterium\NA, and one OTU from Bacteroidetes\Bacteroidia\ Bacteroidaceae\Bacteroides and decrease of one OTU from Proteobacteria\ Betaproteobacteria\Alcaligenaceae\Sutterella. Comparing week 4 to 6, we observed a reversal of the same OTUs from C Christensenellaceae, V muciniphilia and C Mogibacteriaceae. Fecal short chain fatty acids and most of the fecal markers including cholesterol, coprostanol, primary and secondary BAs were not changed significantly except for lithocholic acid, which was increased significantly at week 6 compared to baseline. In summary, SBP consumption increased the abundance of gut microorganisms related to lean body weight, health and longevity, and increased fecal lithocholic acid at week 6 in healthy study participants.

Oral L-glutamine rescues fructose-induced poor fetal outcome by preventing placental triglyceride and uric acid accumulation in Wistar rats

BACKGROUND

Metabolic adaptation of pregnant mothers is crucial for placental development and fetal growth/survival. However, evidence exists that indiscriminate consumption of fructose-enriched drink (FED) during pregnancy disrupts maternal-fetal metabolic tolerance with attendant adverse fetal outcomes. Glutamine supplementation (GLN) has been shown to exert a modulatory effect in metabolic disorders. Nevertheless, the effects of GLN on FED-induced poor fetal outcome, and in particular the impacts on placental uric acid/lipid accumulation are unknown. The present study was conducted to test the hypothesis that oral GLN improves fetal outcome by attenuating placental lipid accumulation and uric acid synthesis in pregnant rats exposed to FED.

MATERIALS AND METHODS

Pregnant Wistar rats (160-180 g) were randomly allotted to control, GLN, FED and FED + GLN groups (6 rats/group). The groups received vehicle by oral gavage, glutamine (1 g/kg) by oral gavage, fructose (10%; w/v) and fructose + glutamine, respectively, through gestation.

RESULTS

Data showed that FED during pregnancy caused placental inefficiency, reduced fetal growth, and caused insulin resistance with correspondent increase in fasting blood glucose and plasma insulin. FED also resulted in an increased placental triglyceride, total cholesterol and de novo uric acid synthesis by activating adenosine deaminase and xanthine oxidase activities. Moreover, FED during pregnancy led to increased lipid peroxidation, lactate production with correspondent decreased adenosine and glucose-6-phosphate dehydrogenase-dependent antioxidant defense. These alterations were abrogated by GLN supplementation.

CONCLUSION

These findings implicate that high FED intake during pregnancy causes poor fetal outcome via defective placental uric acid/triglyceride-dependent mechanism. The findings also suggest that oral GLN improves fetal outcome by ameliorating placental defects through suppression of uric acid/triglyceride accumulation.

Changes of digestive and fermentation properties of Sargassum pallidum polysaccharide after ultrasonic degradation and its impacts on gut microbiota

The in vitro digestive and fermentation properties of Sargassum pallidum polysaccharide (SPP) after ultrasound degradation were investigated. The results showed that SPP and its degraded fractions were not affected by human saliva, but slightly degraded by breaking glycosidic bonds under simulated gastrointestinal digestion. The DPPH radical scavenging activity, α-glucosidase inhibitory activity, and bile acid-binding capacity of SPP and its degraded fractions were decreased after digestion, which was attributed to the reduction of molecular weights (MWs) and viscosity. Furthermore, in vitro fermentation assay indicated that SPP and its degraded fractions showed good fermentability. The predominant compositional monosaccharides including arabinose, galactose, glucose, xylose, and uronic acid were significantly decreased, and the degraded SPP fractions were more easily fermented and utilized by gut bacteria. SPP and its degraded fractions could modulate gut health by decreasing the Firmicutes/Bacteroidetes ratio and increasing the relative abundances of some beneficial genera, such as Prevotella, Dialister, Phascolarctobacterium, Ruminococcus, and Bacteroides. These findings suggested that SPP and its degraded fractions exhibited similar influence on gut microbiota community, but appropriate degraded SPP fractions were more easily fermented by gut microbiota.

Curing piglets from diarrhea and preparation of a healthy microbiome with Bacillus treatment for industrial animal breeding

High-throughput farming of animals for an essential purpose such as large scale health and production of hogs is a challenge for the food industry in the modern world. The problem is that the breeding of livestock for fast growth or high yields of meat is often associated with illness and microbial infection that develop under the breeding conditions. Piglet diarrhea is most common pig disease, leading to heavy mortality and thereby economic loss. We proved that chemical drugs can relieve the symptoms of diarrhea in ill piglets, but they do not treat the underlying cause, i.e. significantly altered bacterial gut flora. Using Illumina sequencing of fecal DNA, we showed that the bacterial gut flora of piglets treated with antibiotics remain close to the ill conditions. However, using Illumina sequencing of fecal DNA from piglets treated with a specific Bacillus (Bacillus subtilis Y-15, B. amyloliquefaciens DN6502 and B. licheniformis SDZD02) demonstrated the efficiency of natural bioproducts not only on curing diarrhea, but also on beneficial bacteria to re-establish in the piglet gut. We therefore propose a new natural “medicine” to be explored by the world farm animal agriculture industry, particularly for sustainable improvement of swine livestock production and health.

Biomarkers Associated With Tumor Ki67 and Cathepsin L Gene Expression in Prostate Cancer Patients Participating in a Presurgical Weight Loss Trial

Our previous presurgical weight loss trial among 40 prostate cancer patients found that rapid (but not slow) weight loss resulted in increased tumor Ki67 and Cathepsin L (CTSL) gene expression. In follow-up analyses, we strove to better understand these unexpected findings. A correlative study was undertaken by performing additional analyses [free fatty acids (FFAs), plasma CTSL, and inflammatory cytokines] on remaining pre-post intervention sera and exploring associations with extant data on tumor Ki67, body composition, physical activity (PA), and fecal microbiota. Positive associations were observed between changes in % body fat and FFAs (ρ = 0.428, p = 0.026), insulin (ρ = 0.432, p = 0.019), and Interleukin-6 (ρ = 0.411, p = 0.041). Change in Ki67 was inversely associated with change in lean mass (ρ = -0.912, p = 0.001) and change in insulin (ρ = -0.650, p = 0.042). Change in insulin was also associated with CTSL (ρ = -0.643, p = 0.024) and FFAs (ρ = -0.700, p = 0.016). Relative abundance of Bifidobacterium was associated with CTSL (ρ = 0.627, p = 0.039) and FFAs (ρ = 0.691, p = 0.019); Firmicutes was positively associated with change in PA (ρ = 0.830, p = 0.003). Contrary to hypotheses, FFAs decreased with systemic fat loss. Moreover, although glucose metabolism improved, it was inversely associated with Ki67 and CTSL. Lean mass loss was highly correlated with increased Ki67. The relationships between prostate tumor Ki67 and CTSL and weight loss associated changes in FFAs, lean mass, and fecal microbiota warrant further investigation.

Dietary Alaska pollock protein alters insulin sensitivity and gut microbiota composition in rats

Fish protein is not only nutritional but also promotes health by improving insulin sensitivity and hypercholesterolemia. Few studies have examined the relationship between gut microbiota and the enhanced insulin sensitivity due to the intake of Alaska pollock protein (APP). Hence, we assessed the glycolytic enzyme inhibitory activity of APP in in vitro study and the alteration of blood glucose level in insulin tolerance test (ITT) and glucose tolerance test (GTT) and gut microbiota following APP intake in the in vivo study. In initial experiments, the glycolytic enzyme (α-amylase, α-glucosidase, and sucrase) inhibitory activities of APP and its digest were not drastically altered compared with that of casein and its digests. In further experiments, rats fed an AIN-93G diet containing 20% (w/w) casein or APP for 8 weeks, and the composition of fecal microbiota analyzed by 16S rRNA amplicon sequence analysis. In addition, at 6 and 7 weeks of administration of experimental diet, insulin and glucose tolerance tests were evaluated, respectively. Compared with dietary casein, dietary APP has blood glucose-lowering activity as evident in the ITT and GTT. Moreover, APP group altered the structure of fecal microbiota, and area under the curves of the ITT and GTT and the relative abundance of Blautia, which is associated with glucose metabolism, tended to be positively correlated (P = 0.08 and 0.10, respectively). This study illustrates a novel finding that APP intake could alter the composition of gut microbiota and improve insulin sensitivity. PRACTICAL APPLICATION: Studies in animals and humans have shown that Alaska pollock protein (APP) intake improves insulin sensitivity, allowing the body to utilize blood glucose more effectively, thereby keeping blood sugar levels under control. Microorganisms residing in the human gut are associated with glucose metabolism. This study shows that the relative APP intake alters the composition of these gut microorganisms, more than casein intake and therefore might prevent hyperglycemia and type 2 diabetes.

Evaluation of antibiotic-induced behavioral changes in mice

Gut microbiota (GM) plays a critical role in health maintenance. Previous reports connected GM with metabolic, immunologic and neurologic pathways. The main purpose of the current investigation was to study whether antibiotic-induced disturbances of GM affects psychological or behavioral conditions on mice as animal model. Mice were exposed to clindamycin or amoxicillin, and their behaviors were evaluated. Antibiotic-treated groups displayed reduced recognition memory and increased depression. No significant changes in the locomotor activity and anxiety were observed. Our data suggested that changes in GM composition by antibiotics may lead to the cognitive and behavioral deficit.

Altered Gut Microbiota and Shift in Bacteroidetes between Young Obese and Normal-Weight Korean Children: A Cross-Sectional Observational Study

Emerging data suggest that the gut microbiome is related to the pathophysiology of obesity. This study is aimed at characterizing the gut microbiota composition between obese and normal-weight Korean children aged 5-13. We collected fecal samples from 22 obese and 24 normal-weight children and performed 16S rRNA gene sequencing using the Illumina MiSeq platform. The relative abundance of the phylum Bacteroidetes was lower in the obese group than in the normal-weight group and showed a significant negative correlation with BMI z-score. Linear discriminative analysis (LDA) coupled with effect size measurement (LEfSe) analysis also revealed that the Bacteroidetes population drove the divergence between the groups. There was no difference in alpha diversity, but beta diversity was significantly different between the normal-weight and obese groups. The gut microbial community was linked to BMI z-score; blood biomarkers associated with inflammation and metabolic syndrome; and dietary intakes of niacin, sodium, vitamin B6, and fat. The gut microbiota of the obese group showed more clustering of genera than that of the normal-weight group. Phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis revealed that the functions related to carbohydrate and lipid metabolism in the microbiota were more enriched in the normal-weight group than in the obese group. Our data may contribute to the understanding of the gut microbial structure of young Korean children in relation to obesity. These findings suggest that Bacteroidetes may be a potential therapeutic target in pediatric obesity.

Effects of synbiotic supplementation on the components of metabolic syndrome in military personnel: a double-blind randomised controlled trial

Introduction

Metabolic syndrome comprises a set of risk factors for chronic diseases including abdominal obesity, increased fasting blood glucose (FBG), altered lipid profile and elevated blood pressure (BP). Due to high prevalence of metabolic syndrome and its complications in the military personnel, the relevant problems should be identified and controlled. Therefore, the present study was conducted to determine the effect of synbiotic supplements on the components of metabolic syndrome in the military personnel with metabolic syndrome.

Methodology

Sixty military personnel with metabolic syndrome were included in this double-blind randomised controlled clinical trial. During the intervention, they were asked to consume one capsule of synbiotic supplement or placebo per day for 8 weeks. Body Mass Index (BMI), waist circumference, BP, FBG and lipid profile were measured before and after the intervention.

Results

The results of the study showed that the synbiotic supplementation had a large significant adjusted effect on the BMI (Cohen’s d=0.82 (95% CI 0.29 to 1.34)). It also had a medium significant adjusted effect on the FBG (Cohen’s d=0.52 (95% CI 0.004 to 1.03)) as well as triglyceride (Cohen’s d=0.65 (95% CI 0.13 to 1.17)).

Conclusion

Findings of the study revealed that synbiotic supplementation may lead to a significant improvement in the BMI, triglyceride and FBG levels in the military personnel. Thus, consumption of synbiotic supplements is recommended as an adjuvant therapy in the military personnel with metabolic syndrome.

Effect of sulfate group on sulfated polysaccharides-induced improvement of metabolic syndrome and gut microbiota dysbiosis in high fat diet-fed mice

Sulfated polysaccharides were shown to benefit metabolic syndrome (MS) and gut microbiota, but the contribution of sulfate group remains unclear. In this study, sulfated polysaccharides from pacific abalone (AGSP) and its desulfated product (D-AGSP) were prepared, and the contribution of sulfate group was analyzed via in vitro and in vivo models. The result showed that sulfate group had no obvious effect on the reaction of AGSP with RAW 264.7 cells, but it affected the growth properties of gut microbes that able to utilize AGSP. The mice experiment showed that D-AGSP reduced weight gain, fat accumulation and lipid metabolism disorder in HFD-fed mice as well as AGSP, and no differences between them were found. Sequencing analysis showed that sulfate group influenced AGSP-induced alterations of the gut microbiota at higher taxonomic levels, some of which had close correlation with the improvement of physiological index. These results implied that sulfate group may partially determine the activities of polysaccharides via gut microbiota-mediated pathway, but the exact mechanisms need further research.

Alteration of gut microbiota affects expression of adiponectin and resistin through modifying DNA methylation in high-fat diet-induced obese mice

BACKGROUND

Adiponectin and resistin are typically secreted by the adipose tissue and are abnormally expressed in obesity. However, the underlying influential factors and mechanisms are to be elucidated. It is well known that the expression of genes is regulated by epigenetics while gut microbiota participates in epigenetic processes through its metabolites such as folate, biotin, and short-chain fatty acids (SCFAs). Therefore, we supposed that alteration of gut microbiota might affect the transcriptional expression of adiponectin and resistin through epigenetic regulation in obesity.

METHODS

C57BL/6J mice were fed either a high-fat diet (34.9% fat by wt., 60% kcal) or a normal-fat diet (4.3% fat by wt., 10% kcal) for 16 weeks, with ampicillin and neomycin delivered via drinking water to interfere with gut microbiota development. Fecal microbiota was analyzed by 16S rRNA high-throughput sequencing. The mRNA expression levels of genes were measured by real-time quantitative RT-PCR. SCFA contents in feces were examined using gas chromatography.

RESULTS

Alteration of the gut microbiota induced by antibiotic use, characterized by a dramatic reduction of the phylum Firmicutes and Actinobacteria and an increase of Proteobacteria with reductions of genera including Lactobacillus, norank_f_Bacteroidales_S24-7_group, Alistipes, Desulfovibrio, Helicobacter, etc., and increases in Bacteroides, Enterobacter, Klebsiella, inhibited the body weight gain in mice fed the high-fat diet instead of the normal-fat diet. The mRNA expression of adiponectin and resistin was upregulated by antibiotic use in mice fed the high-fat diet, accompanied by increased expression of fat oxidation and thermogenesis-related genes (PPAR-α, Pgc-1α, and Atgl) in the fat and/or liver, whereas no change in the expression of adiponectin and resistin was found in mice fed the normal-fat diet. Furthermore, antibiotic use reduced DNA methylation fractions of the adiponectin and resistin promoters and downregulated the expression of DNA methyltransferase 1 and 3a (DNMT1 and DNMT3a) with the high-fat diet feeding.

CONCLUSION

Alteration of gut microbiota induced by antibiotic use may affect the expression of adiponectin and resistin in mice fed the high-fat diet by modifying promoter DNA methylation, thus leading to increased fatty acid oxidation and less body weight gain.

Effects of Inulin Propionate Ester on Obesity-Related Metabolic Syndrome and Intestinal Microbial Homeostasis in Diet-Induced Obese Mice

Short-chain fatty acid (SCFA) plays an important role in improving obesity and related metabolic syndrome induced by high-fat diet. We used the prepared inulin propionate ester (IPE) as a system for the targeted release of propionate to the colon to elucidate the role of IPE in regulating obesity and metabolic syndrome, and intestinal microbial homeostasis, in diet-induced obese mice. With this strategy, IPE significantly increased the SCFA contents in the colon and resulted in significant body weight reduction, insulin resistance amelioration, and gastrointestinal hormone (glucagon-like peptide and peptide YY) secretion (P < 0.05). The IPE intervention reduced liver fatty accumulation, which improved obesity-related fatty liver disease (P < 0.05). IPE supplementation increased the richness and diversity of the microbial community and altered bacterial population at both the phylum and family level. Intestinal microbial results showed that the relative abundance of Desulfovibrionaceae and Erysipelotrichaceae, which promote the production of inflammatory factors, was reduced. Our results demonstrate that IPE can be used as an effective strategy for delivering propionate to obese mice colon, which can ameliorate obesity and associated metabolic syndrome and modify intestinal microbial homeostasis.

Space, time and captivity: quantifying the factors influencing the fecal microbiome of an alpine ungulate

The community of microorganisms in the gut is affected by host species, diet and environment and is linked to normal functioning of the host organism. Although the microbiome fluctuates in response to host demands and environmental changes, there are core groups of microorganisms that remain relatively constant throughout the hosts lifetime. Ruminants are mammals that rely on highly specialized digestive and metabolic modifications, including microbiome adaptations, to persist in extreme environments. Here, we assayed the fecal microbiome of four mountain goat (Oreamnos americanus) populations in western North America. We quantified fecal microbiome diversity and composition among groups in the wild and captivity, across populations and in a single group over time. There were no differences in community evenness or diversity across groups, although we observed a decreasing diversity trend across summer months. Pairwise sample estimates grouped the captive population distinctly from the wild populations, and moderately grouped the southern wild group distinctly from the two northern wild populations. We identified 33 genera modified by captivity, with major differences in key groups associated with cellulose degradation that likely reflect differences in diet. Our findings are consistent with other ruminant studies and provide baseline microbiome data in this enigmatic species, offering valuable insights into the health of wild alpine ungulates.

Comparison Between the Gut Microbiota in Different Gastrointestinal Segments of Large-Tailed Han and Small-Tailed Han Sheep Breeds with High-Throughput Sequencing

Commensal microorganisms are essential to the normal development and function of many aspects of animal biology. However, the dynamic shift patterns of the microbiota of different gut segments in sheep and the correlation between fat type large-tailed phenotype and microbiota remain poorly unknown. This study therefore sought to assess the composition and distribution of the intestinal microbiome, and compared the difference of gut microbiota from different gastrointestinal segments within breeds and same intestinal sections between breeds. For these analyses, 16S rRNA V4 regions from 4 gut sections prepared from each of six individuals (3 from each breed) were sequenced to detect the microbiome composition in these samples. These analyses revealed the presence of 51,173 operational taxonomic units distributed across 24 phyla and 420 genera in these samples, with Firmicutes and Bacteroidetes being the most prevalent phyla of microbes present in these samples. Moreover, the bacterial composition showed distinct microbial communities in different gastrointestinal segments within breed, but showed similar and relative fixed bacterial abundance in the same intestinal segments from individuals of different breeds. We also found that only a few bacterial species (Lachnospiraceae, Akkermansia) were needed to distinguish between Small-tailed Han sheep (STH) and Large-tailed Han sheep (LTH) and their metabolic process maybe influence the fat type large-tailed phenotype formation in sheep. The functional profile analysis revealed that the environment information processing, genetic information processing, and metabolic pathways were enriched in all samples. The main functional roles of the gut microbiota were amino acid metabolism, replication and repair, carbohydrate metabolism, and membrane transport. Finally, our findings suggested that distinguished gut species between STH and LTH have relative fixed and the potential correlation is existing between the intestinal microorganisms and the large-tailed phenotype trait formation of sheep, which may offer clues for further investigation to detect the roles of intestinal microbiota in the metabolism and fat deposition in the tail of sheep.

Preventive antibiotic treatment of calves: emergence of dysbiosis causing propagation of obese state-associated and mobile multidrug resistance-carrying bacteria

In agriculture, antibiotics are used for the treatment and prevention of livestock disease. Antibiotics perturb the bacterial gut composition but the extent of these changes and potential consequences for animal and human health is still debated. Six calves were housed in a controlled environment. Three animals received an injection of the antibiotic florfenicol (Nuflor), and three received no treatment. Faecal samples were collected at 0, 3 and 7 days, and bacterial communities were profiled to assess the impact of a therapy on the gut microbiota. Phylogenetic analysis (16S-rDNA) established that at day 7, antibiotic-treated microbiota showed a 10-fold increase in facultative anaerobic Escherichia spp, a signature of imbalanced microbiota, dysbiosis. The antibiotic resistome showed a high background of antibiotic resistance genes, which did not significantly change in response to florfenicol. However, the maintenance of Escherichia coli plasmid-encoded quinolone, oqxB and propagation of mcr-2, and colistin resistance genes were observed and confirmed by Sanger sequencing. The microbiota of treated animals was enriched with energy harvesting bacteria, common to obese microbial communities. We propose that antibiotic treatment of healthy animals leads to unbalanced, disease- and obese-related microbiota that promotes growth of E. coli carrying resistance genes on mobile elements, potentially increasing the risk of transmission of antibiotic resistant bacteria to humans.

Microbial Alterations and Risk Factors of Breast Cancer: Connections and Mechanistic Insights

Breast cancer-related mortality remains high worldwide, despite tremendous advances in diagnostics and therapeutics; hence, the quest for better strategies for disease management, as well as the identification of modifiable risk factors, continues. With recent leaps in genomic technologies, microbiota have emerged as major players in most cancers, including breast cancer. Interestingly, microbial alterations have been observed with some of the established risk factors of breast cancer, such as obesity, aging and periodontal disease. Higher levels of estrogen, a risk factor for breast cancer that cross-talks with other risk factors such as alcohol intake, obesity, parity, breastfeeding, early menarche and late menopause, are also modulated by microbial dysbiosis. In this review, we discuss the association between known breast cancer risk factors and altered microbiota. An important question related to microbial dysbiosis and cancer is the underlying mechanisms by which alterations in microbiota can support cancer progression. To this end, we review the involvement of microbial metabolites as effector molecules, the modulation of the metabolism of xenobiotics, the induction of systemic immune modulation, and altered responses to therapy owing to microbial dysbiosis. Given the association of breast cancer risk factors with microbial dysbiosis and the multitude of mechanisms altered by dysbiotic microbiota, an impaired microbiome is, in itself, an important risk factor.

Chinese Propolis Prevents Obesity and Metabolism Syndromes Induced by a High Fat Diet and Accompanied by an Altered Gut Microbiota Structure in Mice

The increasing incidence of obesity poses a great threat to public health worldwide. Recent reports also indicate the relevance of obesity in metabolic diseases. Chinese propolis (CP), as a well-studied natural nutraceutical, has shown a beneficial effect on alleviating diabetes mellitus. However, few studies have investigated the effect of CP on weight management and energy balance. We examined the beneficial effects of dietary CP on weight in high-fat diet-fed female and male mice and determined whether CP alters gut microbiota. In this study, dietary CP supplementation reduces body weight and improves insulin resistance in high-fat diet (HFD)-fed mice in a dose-dependent manner. CP treatment also reverses liver weight loss and triglyceride accumulation in association with hepatic steatosis. The 16S rRNA analysis of gut microbiota demonstrated that CP treatment modulates the composition in HFD-fed mice. Our study also suggests that male mice were more sensitive to CP treatment than female mice. Taken together, CP supplementation reduces weight gain and reverses gut microbiome dysbiosis induced by HFD. Further, the effects of CP treatment on metabolic biomarkers and microbiome structure differ by gender.

Use of Physiologically Based Kinetic Modeling to Predict Rat Gut Microbial Metabolism of the Isoflavone Daidzein to S-Equol and Its Consequences for ERα Activation

SCOPE

To predict gut microbial metabolism of xenobiotics and the resulting plasma concentrations of metabolites formed, an in vitro-in silico-based testing strategy is developed using the isoflavone daidzein and its gut microbial metabolite S-equol as model compounds.

METHODS AND RESULTS

Anaerobic rat fecal incubations are optimized and performed to derive the apparent maximum velocities (Vmax ) and Michaelis-Menten constants (Km ) for gut microbial conversion of daidzein to dihydrodaidzein, S-equol, and O-desmethylangolensin, which are input as parameters for a physiologically based kinetic (PBK) model. The inclusion of gut microbiota in the PBK model allows prediction of S-equol concentrations and slightly reduced predicted maximal daidzein concentrations from 2.19 to 2.16 µm. The resulting predicted concentrations of daidzein and S-equol are comparable to in vivo concentrations reported.

CONCLUSION

The optimized in vitro approach to quantify kinetics for gut microbial conversions, and the newly developed PBK model for rats that includes gut microbial metabolism, provide a unique tool to predict the in vivo consequences of daidzein microbial metabolism for systemic exposure of the host to daidzein and its metabolite S-equol. The predictions reveal a dominant role for daidzein in ERα-mediated estrogenicity despite the higher estrogenic potency of its microbial metabolite S-equol.

l-glutamine supplementation exerts cardio-renal protection in estrogen-progestin oral contraceptive-treated female rats

Glycogen and lipid disruptions represent a spectrum of metabolic disorders that are crucial risk factors for cardiovascular disease in estrogen-progestin oral contraceptive (COC) users. l-glutamine (GLN) has been shown to exert a modulatory effect in metabolic disorders-related syndromes. We therefore hypothesized that GLN supplementation would protect against myocardial and renal glycogen-lipid mishandling in COC-treated animals by modulation of Glucose-6-phosphate dehydrogenase (G6PD) and xanthine oxidase (XO) activities. Adult female Wistar rats were randomly allotted into control, GLN, COC and COC + GLN groups (six rats per group). The groups received vehicle (distilled water, p.o.), GLN (1 g/kg), COC containing 1.0 μg ethinylestradiol plus 5.0 μg levonorgestrel and COC plus GLN respectively, daily for 8 weeks. Data showed that treatment with COC led to metabolically-induced obesity with correspondent increased visceral and epicardial fat mass. It also led to increased plasma, myocardial and renal triglyceride, free fatty acid, malondialdehyde (MDA), XO activity, uric acid content and decreased glutathione content and G6PD activity. In addition, COC increased myocardial but not renal glycogen content, and increased myocardial and renal glycogen synthase activity, increased plasma and renal lactate production and plasma aspartate transaminase/alanine aminotransferase (AST/ALT) ratio. However, these alterations were attenuated when supplemented with GLN except plasma AST/ALT ratio. Collectively, the present results indicate that estrogen-progestin oral contraceptive causes metabolically-induced obesity that is accompanied by differential myocardial and renal metabolic disturbances. The findings also suggest that irrespective of varying metabolic phenotypes, GLN exerts protection against cardio-renal dysmetabolism by modulation of XO and G6PD activities.

Effects of inhaled air pollution on markers of integrity, inflammation, and microbiota profiles of the intestines in Apolipoprotein E knockout mice

Air pollution exposure is known to contribute to the progression of cardiovascular disease (CVD) and there is increasing evidence that dysbiosis of the gut microbiome may also play a role in the pathogenesis of CVD, including atherosclerosis. To date, the effects of inhaled air pollution mixtures on the intestinal epithelial barrier (IEB), and microbiota profiles are not well characterized, especially in susceptible individuals with comorbidity. Thus, we investigated the effects of inhaled ubiquitous air-pollutants, wood-smoke (WS) and mixed diesel and gasoline vehicle exhaust (MVE) on alterations in the expression of markers of integrity, inflammation, and microbiota profiles in the intestine of atherosclerotic Apolipoprotein E knockout (ApoE^-/-) mice. To do this, male 8 wk-old ApoE^-/- mice, on a high-fat diet, were exposed to either MVE (300 μg/m³ PM), WS; (∼450 μg/m³ PM), or filtered air (FA) for 6 h/d, 7 d/wk, for 50 d. Immunofluorescence and RT-PCR were used to quantify the expression of IEB components and inflammatory factors, including mucin (Muc)-2, tight junction (TJ) proteins, matrix metalloproteinase (MMP)-9, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β, as well as Toll-like receptor (TLR)-4. Microbial profiling of the intestine was done using Illumina 16S sequencing of V4 16S rRNA PCR amplicons. We observed a decrease in intestinal Muc2 and TJ proteins in both MVE and WS exposures, compared to FA controls, associated with a significant increase in MMP-9, TLR-4, and inflammatory marker expression. Both WS and MVE-exposure resulted in decreased intestinal bacterial diversity, as well as alterations in microbiota profiles, including the Firmicutes: Bacteroidetes ratio at the phylum level. Our findings suggest inhalation exposure to either MVE or WS result in alterations in components involved in mucosal integrity, and also microbiota profiles and diversity, which are associated with increased markers of an inflammatory response.

Perspective: Human Milk Oligosaccharides: Fuel for Childhood Obesity Prevention?

Obesity begins early but has lifelong consequences for health and well-being. Breastfeeding is thought to be preventive against obesity, but the extent and cause of this association are not well understood. Human milk oligosaccharides (HMOs) are abundant in human milk and not present in commercially available infant formula. These complex sugars are thought to contribute to the development of the infant gut microbiome and immune system. Recently, they have been investigated as a potential link between breastfeeding and lower obesity risk. So far, only a few human studies have examined HMO composition of human milk in association with the infant's concurrent anthropometry or subsequent growth in infancy, with conflicting results. However, HMOs have been shown to modulate the gut microbiome profile by selectively promoting the growth of specific bacteria, such as bifidobacteria. Moreover, there are differences in the gut microbiome of lean and obese humans, and there is some evidence that the early composition of the gut microbiome can predict later obesity. Although it seems that HMOs might have a role in infant growth and adiposity, there is not enough consistent evidence to understand their potential role in obesity prevention. More data, particularly from large or longitudinal studies, are needed to clarify the functions of HMOs and other breast-milk components in determining long-term health.

Aged citrus peel (chenpi) extract causes dynamic alteration of colonic microbiota in high-fat diet induced obese mice

Aged citrus peels (chenpi) have been used as a dietary supplement for gastrointestinal health maintenance in China.

Oligosaccharides from Gracilaria lemaneiformis better attenuated high fat diet-induced metabolic syndrome by promoting the Bacteroidales proliferation

Reduction in the degree of polymerization of polysaccharides can improve its bioactivity.

Chemical Cross-Linking Controls in Vitro Fecal Fermentation Rate of High-Amylose Maize Starches and Regulates Gut Microbiota Composition

A slow fermentation rate of dietary fiber could result in a steady metabolite production release and even distribution in the entire colon, increasing the likelihood of meeting the energy requirements of the distal colon. In the present study, we modulated the fermentation rate in an in vitro human fecal fermentation model by applying chemical cross-linking modification to a type 2 resistant starch [i.e., high-amylose maize starch (HAMS)]. Cross-linking modification decreased the gas production (an indicator of the fermentation rate) of HAMS throughout the whole fermentation progress. The butyrate production rate of cross-linked starches decreased gradually with the increase of the cross-linking degree. Certain beneficial gut microbiota such as genera of Blautia and Clostridiales members were remarkably promoted by starches with low and medium cross-linking degrees, whereas HAMS with a high cross-linking degree obviously promoted the abundance of Bacteroides uniformis and Ruminococcus bromii. This finding reveals that cross-linking modification effectively controls the fermentation rate and highlights the modulation metabolite profiles and gut microbiota composition through chemical modification.

Selection of microbial biomarkers with genetic algorithm and principal component analysis

Background

Principal components analysis (PCA) is often used to find characteristic patterns associated with certain diseases by reducing variable numbers before a predictive model is built, particularly when some variables are correlated. Usually, the first two or three components from PCA are used to determine whether individuals can be clustered into two classification groups based on pre-determined criteria: control and disease group. However, a combination of other components may exist which better distinguish diseased individuals from healthy controls. Genetic algorithms (GAs) can be useful and efficient for searching the best combination of variables to build a prediction model. This study aimed to develop a prediction model that combines PCA and a genetic algorithm (GA) for identifying sets of bacterial species associated with obesity and metabolic syndrome (Mets).

Results

The prediction models built using the combination of principal components (PCs) selected by GA were compared to the models built using the top PCs that explained the most variance in the sample and to models built with selected original variables. The advantages of combining PCA with GA were demonstrated.

Conclusions

The proposed algorithm overcomes the limitation of PCA for data analysis. It offers a new way to build prediction models that may improve the prediction accuracy. The variables included in the PCs that were selected by GA can be combined with flexibility for potential clinical applications. The algorithm can be useful for many biological studies where high dimensional data are collected with highly correlated variables.

Long-Term Potable Effects of Alkalescent Mineral Water on Intestinal Microbiota Shift and Physical Conditioning

BACKGROUND

An alkalescent (pH 8.3) mineral water (AMW) of Hita basin, located in the northwestern part of Kyushu island in Japan, has been recognized for the unique quality of ingredients including highly concentrated silicic acid, sodium, potassium, and hydrogen carbonate. The biological effects of AMW intake were evaluated with a particular focus on its "antiobesity" properties through its modulation of the gut microbiota population.

METHODS

Two groups of C57BL6/J mice (8-week-old male) were maintained with a standard diet and tap water (control: TWC group) or AMW (AMW group) for 6 months and the following outputs were quantitated: (1) food and water intake, (2) body weight (weekly), (3) body fat measurements by CT scan (monthly), (4) sera biochemical values (TG, ALT, AST, and ALP), and (5) UCP-1 mRNA in fat tissues (terminal point). Two groups of ICR mice (7-week-old male) were maintained with the same method and their feces were collected at the 0, 1st, 3rd, and 6th month at which time the population rates of gut microbiota were quantitated using metagenomic sequencing analysis of 16S-rRNA.

RESULTS

Among all antiobesity testing items, even though a weekly dietary consumption was increased (p=0.012), both ratios of weight gain (p=1.21E - 10) and visceral fat accumulation (p=0.029) were significantly reduced in the AMW group. Other criteria including water intake (p=0.727), the amounts of total (p=0.1602), and subcutaneous fat accumulation (p=0.052) were within the margin of error and UCP-1 gene expression level (p=0.171) in the AMW group was 3.89-fold higher than that of TWC. Among 8 major gut bacteria families, Lactobacillaceae (increased, p=0.029) and Clostridiaceae (decreased, p=0.029) showed significant shift in the whole population.

CONCLUSION

We observed significantly reduced (1) weight gaining ratio (average -1.86%, up to -3.3%), (2) visceral fat accumulation ratio (average -4.30%, up to -9.1%), and (3) changes in gut microbiota population. All these consequences could support the "health benefit" functionality of AMW.

Microcins in Enterobacteriaceae: Peptide Antimicrobials in the Eco-Active Intestinal Chemosphere

Microcins are low-molecular-weight, ribosomally produced, highly stable, bacterial-inhibitory molecules involved in competitive, and amensalistic interactions between Enterobacteriaceae in the intestine. These interactions take place in a highly complex chemical landscape, the intestinal eco-active chemosphere, composed of chemical substances that positively or negatively influence bacterial growth, including those originated from nutrient uptake, and those produced by the action of the human or animal host and the intestinal microbiome. The contribution of bacteria results from their effect on the host generated molecules, on food and digested food, and organic substances from microbial origin, including from bacterial degradation. Here, we comprehensively review the main chemical substances present in the human intestinal chemosphere, particularly of those having inhibitory effects on microorganisms. With this background, and focusing on Enterobacteriaceae, the most relevant human pathogens from the intestinal microbiota, the microcin’s history and classification, mechanisms of action, and mechanisms involved in microcin’s immunity (in microcin producers) and resistance (non-producers) are reviewed. Products from the chemosphere likely modulate the ecological effects of microcin activity. Several cross-resistance mechanisms are shared by microcins, colicins, bacteriophages, and some conventional antibiotics, which are expected to produce cross-effects. Double-microcin-producing strains (such as microcins MccM and MccH47) have been successfully used for decades in the control of pathogenic gut organisms. Microcins are associated with successful gut colonization, facilitating translocation and invasion, leading to bacteremia, and urinary tract infections. In fact, Escherichia coli strains from the more invasive phylogroups (e.g., B2) are frequently microcinogenic. A publicly accessible APD3 database http://aps.unmc.edu/AP/ shows particular genes encoding microcins in 34.1% of E. coli strains (mostly MccV, MccM, MccH47, and MccI47), and much less in Shigella and Salmonella (<2%). Some 4.65% of Klebsiella pneumoniae are microcinogenic (mostly with MccE492), and even less in Enterobacter or Citrobacter (mostly MccS). The high frequency and variety of microcins in some Enterobacteriaceae indicate key ecological functions, a notion supported by their dominance in the intestinal microbiota of biosynthetic gene clusters involved in the synthesis of post-translationally modified peptide microcins.

Differential rates of group B streptococcus (GBS) colonisation in pregnant women in a racially diverse area of London, UK: a cross-sectional study

OBJECTIVE

To describe the epidemiology of maternal group B streptococcus (GBS) colonisation by racial group.

DESIGN

Cross-sectional study.

SETTING

Antenatal clinics in London North West University Healthcare NHS Trust.

POPULATION

Pregnant women.

METHODS

Group B streptococcus (GBS) colonisation status was recorded during a screening programme for the prevention of invasive early-onset GBS infection. Information regarding age, address, ethnicity, parity, mode of delivery, body mass index (BMI), and diabetes was routinely collected. Data were analysed by multivariable analysis.

MAIN OUTCOME MEASURES

Association between GBS colonisation and putative risk factors.

RESULTS

Overall, 29.1% (1836/6309) of the women were colonized with GBS. Multivariable analysis showed significantly higher colonisation among women of black African origin (39.5%; OR = 1.57) compared with white British women (27.4%), and lowest colonisation in women of South Asian origin (23.3%; OR = 0.8). Higher parity (≥2) was associated with higher colonisation (35.3%), with the odds of colonisation over 40% higher than for nulliparous women. Increasing BMI was associated with an incremental rise in colonisation from 23 to 35%. Colonisation was not associated with age, season or mode of testing.

CONCLUSION

This study identified high maternal GBS colonisation rates in a racially and socially diverse population. The highest rates were seen in women of black African origin and also with higher parity and BMI. Further research is needed to understand the relationship between these factors and rectovaginal colonisation.

TWEETABLE ABSTRACT

Study of group B streptococcus colonisation in pregnant women in London shows highest rates in black African women and those with high BMI and parity.

The effects of antibiotics and melatonin on hepato-intestinal inflammation and gut microbial dysbiosis induced by a short-term high-fat diet consumption in rats

High-fat diet (HFD) consumption leads to metabolic disorders, gastrointestinal dysfunction and intestinal dysbiosis. Antibiotics also disrupt the composition of intestinal microbiota. The aim of the present study was to investigate the impact of a short-term feeding with HFD on oxidative status, enteric microbiota, intestinal motility and the effects of antibiotics and/or melatonin treatments on diet-induced hepato-intestinal dysfunction and inflammation. Male Sprague-Dawley rats were pair-fed with either standard chow or HFD (45 % fat) and were given tap water or melatonin (4 mg/kg per d) or melatonin plus antibiotics (ABX; neomycin, ampicillin, metronidazole; each 1 g/l) in drinking water for 2 weeks. On the 14th day, colonic motility was measured and the next day intestinal transit was assessed using charcoal propagation. Trunk blood, liver and intestine samples were removed for biochemical and histopathological evaluations, and faeces were collected for microbiota analysis. A 2-week HFD feeding increased blood glucose level and perirenal fat weight, induced low-level hepatic and intestinal inflammation, delayed intestinal transit, led to deterioration of epithelial tight junctions and overgrowth of colonic bacteria. Melatonin intake in HFD-fed rats reduced ileal inflammation, colonic motility and perirenal fat accumulation. ABX abolished increases in fat accumulation and blood glucose, reduced ileal oxidative damage, suppressed HFD-induced overgrowth in colonic bacteria, and reversed HFD-induced delay in intestinal transit; however, hepatic neutrophil accumulation, hepatic injury and dysfunction were further enhanced. In conclusion, the results demonstrate that even a short-term HFD ingestion results in hepato-intestinal inflammatory state and alterations in bacterial populations, which may be worsened with antibiotic intake, but alleviated by melatonin.

Comparative analysis of the gut microbiota of the blue fox (Alopex lagopus) and raccoon dog (Nyctereutes procyonoides)

The goal of this study is to compare the gut microbiota of domestic blue fox (Alopex lagopus) and raccoon dog (Nyctereutes procyonoides) to provide better understanding of their intestinal gut microbiota. We analyzed the structure of fecal microbes in 40 blue foxes and 40 raccoon dogs that were raised under same conditions, using high-throughput Illumina sequencing targeting the V3-V4 region of the 16S rRNA gene. In total, 295,146 sequence reads were obtained. The average number of operational taxonomical units in the two group samples was 194 to 286. Firmicutes (blue fox 73.40%, raccoon dog 46.90%) and Bacteroidetes (blue fox 21.92%, raccoon dog 44.25%) were the most abundant phyla in the gut of blue fox and raccoon dog. At the genus level, Prevotella (blue fox 16.89%, raccoon dog 36.22%), Blautia (blue fox 9.02%, raccoon dog 13.72%), and Peptostreptococcaeae_incertae_sedi (blue fox 22.41%, raccoon dog 2.84%) were commonly presented in the gut of two kinds of animal. Principal coordinates analysis showed that the microbial communities were different between blue fox and raccoon dog. The Firmicutes-to-Bacteroidetes ratio was higher in blue foxes (3:1) than in raccoon dogs (1:1). Moreover, Peptostreptococcaeae_incertae_sedi and Prevotella, were more abundant in the gut of blue fox, whereas the abundance of Prevotella and Blautia were higher in the gut of raccoon dog. In conclusion, the present study revealed the difference of the gut microbial composition between blue fox and raccoon dog under the same diet conditions.

Dietary interventions, intestinal microenvironment, and obesity: a systematic review

CONTEXT

Obesity has been linked to the intestinal microenvironment. Diet plays an important role in obesity and has been associated with microbiota.

OBJECTIVE

This systematic review sought to evaluate the scientific evidence on the effect of dietary modification, including supplementation with prebiotics and probiotics, on microbiota diversity in obesity.

DATA SOURCES

A systematic search was performed in the MEDLINE and EMBASE databases. Studies were considered eligible if they were clinical trials evaluating dietary intervention and microbiota, body weight, or clinical parameters in obesity.

DATA EXTRACTION

Data were extracted by 2 independent reviewers.

RESULTS

From 168 articles identified, 20 were included (n = 931 participants). Increased phyla abundance after food interventions was the main finding in relation to microbiota. Regarding the impact of interventions, increased insulin sensitivity, reduced levels of inflammatory markers, and reduced body mass index were shown in several studies.

CONCLUSIONS

Interventions that modulate microbiota, especially prebiotics, show encouraging results in treating obesity, improving insulin levels, inflammatory markers, and body mass index. Because the studies included in this review were heterogeneous, it is difficult to achieve conclusive and definitive results.

Effect of Chronic Consumption of Sweeteners on Microbiota and Immunity in the Small Intestine of Young Mice

The consumption of sweeteners has increased as a measure to reduce the consumption of calories and thus combat obesity and diabetes. Sweeteners are found in a large number of products, so chronic consumption has been little explored. The objective of the study was to evaluate the effect of chronic sweetener consumption on the microbiota and immunity of the small intestine in young mice. We used 72 CD1 mice of 21 days old, divided into 3 groups: (i) No treatment, (ii) Group A (6 weeks of treatment), and (iii) Group B (12 weeks of treatment). Groups A and B were divided into 4 subgroups: Control (CL), Sucrose (Suc), Splenda® (Spl), and Svetia® (Sv). The following were determined: anthropometric parameters, percentage of lymphocytes of Peyer's patches and lamina propria, IL-6, IL-17, leptin, resistin, C-peptide, and TNF-α. From feces, the microbiota of the small intestine was identified. The BMI was not modified; the mice preferred the consumption of Splenda® and Svetia®. The percentage of CD3+ lymphocytes in Peyer's patches was increased. In the lamina propria, Svetia® increased the percentage of CD3+ lymphocytes, but Splenda® decreases it. The Splenda® and Svetia® subgroups elevate leptin, C-peptide, IL-6, and IL-17, with reduction of resistin. The predominant genus in all groups was Bacillus. The chronic consumption of sweeteners increases the population of lymphocytes in the mucosa of the small intestine. Maybe, Bacillus have the ability to adapt to sweeteners regardless of the origin or nutritional contribution of the same.

An overview of microbiome based strategies on anti-obesity

With the significant global obesity epidemic and emerging strong scientific evidence that connected gut microbiota to obesity, intervening obesity by targeting gut microbiota has become a trendy strategy. Particularly the application of probiotics has become remarkably popular because of their expected association with gut microbiota modulation. Although there are many literatures on the effects of probiotics in obese animal models, most of them reported the effects of probiotic bacteria on metabolic indications with limited information on anti-obesity itself. Besides, some probiotics have been shown to reduce certain metabolic symptoms but they failed to achieve weight loss. This report reviewed the current literatures on the anti-obesity effects of next-generation probiotics in various animal obesity models and discussed the beneficial potential of fecal microbiota transplantation in treating obesity in humans. The purpose of this article is to help guide further research improve the probiotic bacteria experiments in more precise animal obesity models by standardizing the anti-obesogenesis, obesity control, and treatment assays and hopefully the evidence-based investigations on harnessing gut microbiota through next-generation probiotics or fecal microbiota transplantation will develop new interventions to promote and achieve anti-obesity.

Hass Avocado Inclusion in a Weight-Loss Diet Supported Weight Loss and Altered Gut Microbiota: A 12-Week Randomized, Parallel-Controlled Trial

BACKGROUND

Avocados contain fiber, lutein, and vitamin E, and they are a rich source of MUFAs. The effect of including an avocado daily as part of a hypocaloric weight-loss diet on weight loss is not known.

OBJECTIVE

The aim of this study was to determine the effect of daily avocado consumption as part of a hypocaloric diet on weight loss, body composition, satiety, biomarkers of inflammation, and intestinal microbiota composition.

METHODS

In this randomized, parallel-controlled, open-label, 2-arm intervention study, 51 healthy overweight/obese women and men were assigned to a hypocaloric diet with 1 Hass avocado daily (AVO; n = 24) or a hypocaloric diet (CTRL; n = 27) without daily avocado for 12 wk. Serum markers and intestinal microbiota were analyzed at baseline and week 12.

RESULTS

Both groups experienced significant weight loss, decrease in BMI (in kg/m2), total body fat, and visceral adipose tissue, respectively (AVO: -2.3 ± 2 kg, -0.8 ± 0.8, -1.1% ± 2%, and -81.2 ± 118 g; CTRL: -2.6 ± 3.6 kg, -0.9 ± 1, -1.5% ± 2%, and -87.4 ± 216 g). We observed a significant decrease in serum glucose over time in the control group compared with the AVO group. There was no change between the groups in serum triglyceride, but a significant decrease from baseline to 12 wk was observed in the AVO group. Serum hepatic growth factor (HGF) and relative proportion of bacterial phyla (Firmicutes and Bacteroidetes), family (Bacteroidaceae and Erysipelotrichaceae), and genus (Bacteroides, Clostridium, Methanosphaera, and Candidatus Soleaferrea) were significantly altered in the AVO group compared with the CTRL group. A trend to decrease in serum inflammatory factors IL-1β (P = 0.07) and C-reactive protein (P = 0.074) was observed in the AVO group compared with CTRL.

CONCLUSIONS

Daily Hass avocado consumption as part of a hypocaloric diet supported weight loss, a decrease in serum HGF, and an increase in the abundance of bacteria involved in plant polysaccharide fermentation. This trial was registered at clinicaltrials.gov as NCT02953158.

The specific use of alginate from Laminaria japonica by Bacteroides species determined its modulation of the Bacteroides community

Accumulating studies showed that the beneficial actions of polysaccharides were closely associated with an improvement of the gut microbiota, but mechanisms that link polysaccharides and gut microbiota alterations are ill defined. Alginate from Laminaria japonica (LJP-A) can avoid being digested by the upper digestive tract and reach the colon where it can improve the gut microbiota community. LJP-A increased the relative abundance of some Bacteroidaceae members, e.g. Bacteroides species. The distribution of Bacteroides species in the gut is specific to the individual, and the specific use of LJP-A by Bacteroides species can determine LJP-A-induced alterations of the intestinal Bacteroides community, in which carbon source-based syntrophic interactions occur in Bacteroides species of the human gut microbial ecosystem. Compared to other species, Bacteroides finegoldii responded more positively to LJP-A intervention, and its properties may have a close connection with the bioactivities of LJP-A. This study provides a rationale for personalized treatment with dietary polysaccharides that were optimally fermented within a particular individual.

Gut microbiome and its role in obesity and insulin resistance

Obesity is a complex metabolic disease caused, in part, by the interaction between an individual's genetics, metabolism, and environment. Emerging evidence supports the role of gut microbiota in mediating the interaction between the host and environment by extracting energy from food otherwise indigestible by the host and producing metabolites and cytokines that affect host metabolism. Furthermore, gut microbial imbalance or dysbiosis has been shown in metabolic diseases including obesity, and recent studies are beginning to unravel the mechanisms involved. The gut microbiota affects host metabolism and obesity through several pathways involving gut barrier integrity, production of metabolites affecting satiety and insulin resistance, epigenetic factors, and metabolism of bile acids and subsequent changes in metabolic signaling. While the field of gut microbiome and its role in obesity is early in its stage of development, it holds a promising future in providing us with novel therapeutic targets that may restore the gut microbiome to a healthy state and help in the prevention and treatment of obesity.

Preventive effects of l-glutamine on gestational fructose-induced cardiac hypertrophy: involvement of pyruvate dehydrogenase kinase-4

Gestational fructose exposure has detrimental health consequences on both the maternal and fetus or offspring in the early or later life, contributing to epidemic rise in cardiometabolic syndrome including cardiac events. l-Glutamine has been shown to mitigate cardiac metabolic stress. However, the effect of l-glutamine on cardiac hypertrophy induced by gestational fructose exposure is not known. We therefore hypothesized that l-glutamine would prevent gestational fructose-induced cardiac hypertrophy, possibly by suppression of pyruvate dehydrogenase kinase-4 (PDK-4). Pregnant Wistar rats were allotted into the control, l-glutamine, gestational fructose exposure, and gestational fructose exposure plus l-glutamine groups (6 rats in each group). The groups received distilled water (vehicle, per os), 1 g/kg body weight l-glutamine (per os), 10% fructose (w/v) and 10% fructose (w/v) plus 1 g/kg l-glutamine (per os), respectively, daily for 19 days. Data from this study showed that gestational fructose-enriched drink caused cardiac hypertrophy with correspondent body weight gain, glucose dysregulation, increased cardiac PDK-4, triglyceride, glycogen, lactate, and uric acid production. On the other hand, defective glutathione-dependent antioxidant barrier was also observed in pregnant rats taking fructose-enriched drink. However, the gestational fructose-induced cardiac hypertrophy and its correlates were attenuated by l-glutamine. The present results demonstrate that gestational fructose-enriched drink induces cardiac hypertrophy that is accompanied by increased PDK-4. The findings also suggest that the inhibitory effect of l-glutamine on PDK-4 prevents the development of cardiac hypertrophy, thereby implying that PDK-4 may be a potential novel therapeutic intervention for cardiac hypertrophy especially in pregnancy.

Supplementation with Sodium Butyrate Modulates the Composition of the Gut Microbiota and Ameliorates High-Fat Diet-Induced Obesity in Mice

BACKGROUND

Short-chain fatty acids (SCFAs) have been reported to ameliorate obesity. However, the underlying mechanisms require further investigation.

OBJECTIVE

The aim of this study was to determine the role of butyrate, an SCFA, in the regulation of obesity, low-grade chronic inflammation, and alterations of microbiota composition in mice.

METHODS

Male C57BL/6J mice, 4-5 wk of age, were divided into 3 groups (n = 8 mice/group): low-fat diet (LFD; 10% energy from fat), high-fat diet (HFD; 45% energy from fat), or high-fat diet plus sodium butyrate (HSB). HSB mice received sodium butyrate at a concentration of 0.1 M in drinking water for 12 wk. Measures of inflammation, obesity, and intestinal integrity were assessed. Serum lipopolysaccharide (LPS) concentrations were measured in the 3 groups. Fecal samples were collected for gut microbiota analysis.

RESULTS

In HFD mice, body weight gain and hepatic triglyceride (TG), serum interleukin-6 (IL-6), and serum tumor necrosis factor (TNF)-α levels were 1-4 times higher than those in LFD mice (P < 0.05); they were 34-42% lower in HSB mice compared with HFD mice (P < 0.05). The HFD group had 28%-48% lower mRNA expression of both Tjp1 and Ocln in the ileum and colon compared with levels in LFD or HSB mice (P < 0.05), whereas there was no difference in expression levels between LFD and HSB mice. Furthermore, in HSB mice, serum LPS concentration was 53% lower compared with that in HFD mice but still 23% higher than that in LFD mice (P < 0.05). Results from principal component analysis showed that HSB and LFD mice had a similar gut microbiota structure, which was significantly different from that in HFD mice (P < 0.05).

CONCLUSIONS

Sodium butyrate administration beneficially changed HFD-induced gut microbiota composition and improved intestinal barrier, leading to lower serum LPS concentrations. These changes may correspond with improvements in obesity-related lipid accumulation and low-grade chronic inflammation.

The role of Small Intestinal Bacterial Overgrowth (SIBO) in Non-alcoholic Fatty Liver Disease (NAFLD) patients evaluated using Controlled Attenuation Parameter (CAP) Transient Elastography (TE): a tertiary referral center experience

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is an emerging disease, where it can progress to non-alcoholic steatohepatitis (NASH) and lead to liver cirrhosis or liver cancer. Small intestinal bacterial overgrowth (SIBO) has been hypothesized to play an important role in NAFLD development and progression, however, there is still conflicting data about this phenomenon. Transient Elastography (TE) examination using controlled attenuation parameter (CAP) has been validated for liver disease progression assessment in NAFLD. It is non-invasive method and easy to perform in clinical practice. Therefore, we would like to know the role of SIBO in NAFLD and its possible impact on disease progression.

METHODS

A cross-sectional design study performed at outpatient's Hepatobiliary clinic at tertiary referral university hospital in Jakarta. All recruited study subjects based on inclusions criteria underwent laboratory examination, transabdominal ultrasound examination, CAP-TE 502 (by Echosens, France), and glucose hydrogen breath test (GHBT) using portable hydrogen breath test apparatus (Gastro+™ Gastrolyzer by Bedfont Scientific Ltd). Stool sample examination was performed using RT-PCR.

RESULTS

This study recruited 160 subjects with median age of 58 (22-78) years and 108 (67.5%) of them are female. SIBO (65,5%), DM (70.8%), dyslipidemia (75.2%), obesity (76.6%), and metabolic syndrome (73%) were more prevalent in NAFLD than non-NAFLD population. Bivariate analysis showed no significant association between SIBO and NAFLD development (p = 0.191; PR 0.871; CI 95% [0.306-1.269]). SIBO was also not associated with significant hepatic steatosis (p = 0.951; PR = 0.951; CI 95% [0.452-2.239]) and fibrosis (p = 0.371; PR = 1.369; CI 95% [0.608-3.772]). However, the presence of central obesity has significantly associated with the presence of SIBO (p = 0.001; PR = 0.378; CI 95% [0.021-0.478]). Based on stool sample analysis from 60 NAFLD patients, there is a significant correlation using Spearmen test between the presence of Bacteroides and the stage of fibrosis (p .037). Further analysis between obese NAFLD patients and non-obese NAFLD patients showing that there is a significant decrease of Bifidobacteria (p .047) and Lactobacillus (p .038) in obese NAFLD patients and a tendency of increase Bacteroides in obese NAFLD patients (p .572).

CONCLUSIONS

SIBO is not associated with NAFLD development and progression.