Effects of four Bifidobacteria on obesity in high-fat diet induced rats

Application of antibiotics before 3 years of age increases the risk of childhood overweight and obesity

Childhood obesity and antibiotics abuse have become global health problems. It is necessary to explore the correlation between application of antibiotics for children under 3 and the risk of overweight and obesity in children. In the present study, young children aged 3 (36-38 months) were investigated using a face-to-face questionnaire survey. These children were admitted to Dongying City Children's Hospital from December 2017 to May 2019, and the effective sample size was 4,258. According to the body mass index (BMI), young children were divided into two groups, including emaciation and normal group as well as overweight and obesity group. Univariate analysis was performed to identify the possible influencing factors between the two groups using chi-square test. A difference of P<0.05 indicated statistical significance of a certain factor between the two groups, which could be adopted as an influencing factor in Logistic regression analysis. In addition, odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were employed to quantify the correlation of antibiotic application with the risk of overweight and obesity. A total of 3,322 young children (78.0%) were included in the antibiotic group while the remaining 936 (22.0%) were enrolled in the non-antibiotic group. Logistic regression analysis revealed that antibiotic application increased the risk of overweight and obesity among the 3-year-old young children (OR, 1.44; 95% CI, 1.03-2.01). In addition, application of antibiotics for five times or higher significantly increased the risk of overweight and obesity (OR, 1.73; 95% CI, 1.07-2.80), and such risks were more significant in children who were administered antibiotics for the first time within 6 months of age (OR, 1.71; 95% CI, 1.08-2.69). The application of antibiotics in infants and young children was thus revealed to increase the risk of overweight and obesity at the age of 3 in a frequency-dependent manner.

The Influence of Probiotics on the Firmicutes/Bacteroidetes Ratio in the Treatment of Obesity and Inflammatory Bowel disease

The two most important bacterial phyla in the gastrointestinal tract, Firmicutes and Bacteroidetes, have gained much attention in recent years. The Firmicutes/Bacteroidetes (F/B) ratio is widely accepted to have an important influence in maintaining normal intestinal homeostasis. Increased or decreased F/B ratio is regarded as dysbiosis, whereby the former is usually observed with obesity, and the latter with inflammatory bowel disease (IBD). Probiotics as live microorganisms can confer health benefits to the host when administered in adequate amounts. There is considerable evidence of their nutritional and immunosuppressive properties including reports that elucidate the association of probiotics with the F/B ratio, obesity, and IBD. Orally administered probiotics can contribute to the restoration of dysbiotic microbiota and to the prevention of obesity or IBD. However, as the effects of different probiotics on the F/B ratio differ, selecting the appropriate species or mixture is crucial. The most commonly tested probiotics for modifying the F/B ratio and treating obesity and IBD are from the genus Lactobacillus. In this paper, we review the effects of probiotics on the F/B ratio that lead to weight loss or immunosuppression.

Lactobacillus acidophilus Antimicrobial Peptide Is Antagonistic to Aeromonas hydrophila

We identified an antimicrobial peptide (AMP) from Lactobacillus acidophilus that was antagonistic to Aeromonas hydrophila. In vitro studies such as well-diffusion and field trials revealed that the AMP was active against A. hydrophila. The field trials of AMP using A. hydrophila-infected Channa striatus with a mannone oligosaccharide (MOS) prebiotic, A. hydrophila antigens, A. hydrophila-infected fish serum, L. acidophilus, and Lactobacillus cell free-supernatant (LABS-CFS) on an indicator organism further revealed that the antimicrobial agent could protect C. striatus. Other than the AMP, none of the above were able to eliminate the infectious agent A. hydrophila, and were only able to delay the death rate for 3-4 days. Thus, we conclude that the AMP is antagonistic to A. hydrophila and may be used for treatment of A. hydrophila infections. Subsequent L. acidophilus whole-genome sequence analyses enabled an understanding of the (probable) gene arrangement and its location on the chromosome. This information may be useful in the generation of recombinant peptides to produce larger quantities for treatment.

Supplementation with Combined Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 Across Development Reveals Sex Differences in Physiological and Behavioural Effects of Western Diet in Long-Evans Rats

The gut microbiome affects various physiological and psychological processes in animals and humans, and environmental influences profoundly impact its composition. Disorders such as anxiety, obesity, and inflammation have been associated with certain microbiome compositions, which may be modulated in early life. In 62 Long–Evans rats, we characterised the effects of lifelong Bifidobacterium longum R0175 and Lactobacillus helveticus R0052 administration—along with Western diet exposure—on later anxiety, metabolic consequences, and inflammation. We found that the probiotic formulation altered specific anxiety-like behaviours in adulthood. We further show distinct sex differences in metabolic measures. In females, probiotic treatment increased calorie intake and leptin levels without affecting body weight. In males, the probiotic seemed to mitigate the effects of Western diet on adult weight gain and calorie intake, without altering leptin levels. The greatest inflammatory response was seen in male, Western-diet-exposed, and probiotic-treated rats, which may be related to levels of specific steroid hormones in these groups. These results suggest that early-life probiotic supplementation and diet exposure can have particular implications on adult health in a sex-dependent manner, and highlight the need for further studies to examine the health outcomes of probiotic treatment in both sexes.

Intervention with kimchi microbial community ameliorates obesity by regulating gut microbiota

The objective of this study was to evaluate anti-obesity effects of kimchi microbial community (KMC) on obesity and gut microbiota using a high fat diet-induced mouse model compared to effects of a single strain. Administration of KMC decreased body weight, adipose tissue, and liver weight gains. Relative content of Muribaculaceae in the gut of the KMC-treated group was higher than that in the high-fat diet (HFD) group whereas relative contents of Akkermansiaceae, Coriobacteriaceae, and Erysipelotrichaceae were lower in KMC-treated group. Metabolic profile of blood was found to change differently according to the administration of KMC and a single strain of Lactobacillus plantarum. Serum metabolites significantly increased in the HFD group but decreased in the KMC-treated group included arachidic acid, stearic acid, fumaric acid, and glucose, suggesting that the administration of KMC could influence energy metabolism. The main genus in KMC was not detected in guts of mice in KMC-treated group. Since the use of KMC has advantages in terms of safety, it has potential to improve gut microbial community for obese people.

Probiotic Enterococcus faecalis AG5 mitigated high fat diet induced obesity and produced propionic acid stimulated apoptosis in 3T3-L1 pre-adipocyte

AIMS

Probiotics and their metabolites (SCFA) can regulate energy homeostasis. The present study thus evaluates the synergistic effect of probiotic Enterococcus faecalis AG5 on HFD induced obesity and the role of propionic acid (PA) in apoptosis induction of 3T3-L1 pre-adipocyte.

METHODS

Male Wistar rats (n = 24) were used to develop an HFD induced obesity model for 24 weeks. The effect of the orally administered probiotic AG5 (18th-24th weeks, 1 × 10⁹ CFU/ml) was evaluated using physiological, biochemical, anthropometry, histopathological and serological analyses. Apoptosis in 3T3-L1 pre-adipocyte was assessed using flow cytometry, protein expression of PPARγ, 5-LOX, NF-κB, p-AKT, caspase 10 and detection of caspase 3/7 by Immunofluorescence confirmed the apoptosis induced by PA.

KEY FINDINGS

Probiotic AG5 significantly reduced body weight, BMI, serum cholesterol, triglycerides (p < 0.05) and improved HDL, insulin and leptin but lowered LDL and VLDL (p > 0.05). An inflammatory response was reduced as evident by TNF-α IHC. AG5 reduced adipocyte hypertrophy and fatty acid accumulation. Flow cytometry confirmed late apoptosis in PA-AG5 and standard PA treated 3T3-L1 cells. 5-LOX inhibition is associated with apoptosis induction, and increased caspase 1p 10 is related to cell death initiation. The study initially showed a low PPARγ activity inhibiting 5-LOX which may relate to adipose apoptosis. Finally caspase 3/7 detection using immunofluorescence proved the role of PA in adipocyte apoptosis.

SIGNIFICANCE

The present study is a novel approach towards obesity mitigation involving adipocyte apoptosis. The role of SCFA in adipocyte apoptosis is very limited which can prove to be novel therapeutic approach in the future.

The Gut Microbiota Profile in Children with Prader-Willi Syndrome

Although gut microbiota has been suggested to play a role in disease phenotypes of Prader-Willi syndrome (PWS), little is known about its composition in affected children and how it relates to hyperphagia. This cross-sectional study aimed to characterize the gut bacterial and fungal communities of children with PWS, and to determine associations with hyperphagia. Fecal samples were collected from 25 children with PWS and 25 age-, sex-, and body mass index-matched controls. Dietary intake data, hyperphagia scores, and relevant clinical information were also obtained. Fecal bacterial and fungal communities were characterized by 16S rRNA and ITS2 sequencing, respectively. Overall bacterial α-diversity and compositions of PWS were not different from those of the controls, but 13 bacterial genera were identified to be differentially abundant. Interestingly, the fungal community, as well as specific genera, were different between PWS and controls. The majority of the variation in the gut microbiota was not attributed to differences in dietary intake or the impact of genotype. Hyperphagia scores were associated with fungal α-diversity and relative abundance of several taxa, such as Staphylococcus, Clostridium, SMB53, and Candida. Further longitudinal studies correlating changes in the microbiome with the degree of hyperphagia and studies integrating multi-omics data are warranted.

Gut microbiota of obese and diabetic Thai subjects and interplay with dietary habits and blood profiles

Obesity and type 2 diabetes mellitus (T2DM) have become major public health issues globally. Recent research indicates that intestinal microbiota play roles in metabolic disorders. Though there are numerous studies focusing on gut microbiota of health and obesity states, those are primarily focused on Western countries. Comparatively, only a few investigations exist on gut microbiota of people from Asian countries. In this study, the fecal microbiota of 30 adult volunteers living in Chiang Rai Province, Thailand were examined using next-generation sequencing (NGS) in association with blood profiles and dietary habits. Subjects were categorized by body mass index (BMI) and health status as follows; lean (L) = 8, overweight (OV) = 8, obese (OB) = 7 and diagnosed T2DM = 7. Members of T2DM group showed differences in dietary consumption and fasting glucose level compared to BMI groups. A low level of high-density cholesterol (HDL) was observed in the OB group. Principal coordinate analysis (PCoA) revealed that microbial communities of T2DM subjects were clearly distinct from those of OB. An analogous pattern was additionally illustrated by multiple factor analysis (MFA) based on dietary habits, blood profiles, and fecal gut microbiota in BMI and T2DM groups. In all four groups, Bacteroidetes and Firmicutes were the predominant phyla. Abundance of Faecalibacterium prausnitzii, a butyrate-producing bacterium, was significantly higher in OB than that in other groups. This study is the first to examine the gut microbiota of adult Thais in association with dietary intake and blood profiles and will provide the platform for future investigations.

Administration of indigenous probiotics modulate high-fat diet-induced metabolic syndrome in Sprague Dawley rats

Modulation of the gut microbiota by probiotics, is emerging as a promising approach for the management of metabolic diseases but due to their species and strain specific response, isolation of new probiotic strains is gaining importance. The present study was designed to assess the effect of isolated and well characterised indigenous probiotics, Lactobacillus pentosus GSSK2, Lactobacillus fermentum PUM and Lactobacillus plantarum GS26A in high fat diet (HFD) induced metabolic syndrome. It was observed that though supplementation of all three probiotics for 12 weeks to Sprague Dawley rats fed with HFD, ameliorated the anthropometric parameters, but L. pentosus GSSK2 showed maximum reduction in weight gain while maximum decrease in abdominal circumference, Lee's index, BMI and visceral fat deposition was observed in L. plantarum GS26A compared with HFD animals. Further, administration of L. plantarum GS26A to HFD animals led to significant increase in lactic acid bacteria count and lipid excretion in feces followed by L. pentosus GSSK2 and L. fermentum PUM compared with counter controls. Additionally, both L. pentosus GSSK2 and L. plantarum GS26A exhibited improved glucose tolerance, liver biomarkers, alleviated oxidative stress and restored the histoarchitechture of adipose tissue, colon and liver compared with HFD animals. The study highlights the prophylactic potential of isolated probiotics in experimental metabolic syndrome model and revealed that amongst all three probiotics, L. pentosus GSSK2 and L. plantarum GS26A were equally effective and more promising than L. fermentum PUM in improving metabolic dysfunctions and may be employed as functional foods but needs to be correlated clinically.

Effect of Probiotics Bacillus coagulans and Lactobacillus plantarum on Lipid Profile and Feces Bacteria of Rats Fed Cholesterol-Enriched Diet

The aim of this study was to investigate the effect of Lactobacillus plantarum and Bacillus coagulans on serum lipid profile and lowering potential of probiotic in hypercholesterolemic rats. Twenty-eight male Wistar rats were divided into four groups as follows: (1) control group, fed standard commercial diet; (2) HC group, fed high-cholesterol diet; (3) HC + LP group, fed high-cholesterol diet and gavaging of L. plantarum; and (4) HC + BC group fed high-cholesterol diet and gavaging of B. coagulans. After 28 and 50 days, serum lipid profile; serum ALT and AST; the body and organ weights; fecal total count; Enterobacteriaceae, L. plantarum, and B. coagulans counts; and blood glucose tolerance were measured. We observed that levels of triglyceride, cholesterol, LDL, VLDL, and atherogenic index in serum were significantly lower in the HC + probiotic groups. Also, serum ALT and AST were significantly decreased in probiotic-treated groups. In addition, we found that feeding of a high-cholesterol diet for 50 days produced significant increases in the body weight, in addition to the fact that the administration of L. plantarum and B. coagulans has considerably reduced the body weight gain. B. coagulans and L. plantarum can survive passing through the upper-gastrointestinal tract after oral feeding to the rats and colonized in their colon. These bacteria could be exploited as a potential biotherapeutic remedy to reduce TC, TG, LDL, VLDL, and atherogenic index in hypercholesterolemic condition.

Autologous fecal transplantation from a lean state potentiates caloric restriction effects on body weight and adiposity in obese mice

Autologous fecal transplantation (FT-A) emerges as a promising strategy to modulate gut microbiota with minimal side effects since individual´s own feces are transplanted. With the premise of improving obesity and its associated disorders, we investigated if fecal microbiota transplantation (FMT), heterologous and autologous, potentiates the effects of a moderate caloric restriction (CR) in high-fat diet (HFD)-induced obese mice. Mice were randomized into control, HFD, CR (12 weeks on HFD and 6 weeks under CR), FT-H (similar to CR and FMT carried out with feces from controls, weeks 17 & 18), and FT-A (administration of their own feces before developing obesity at weeks 17 & 18). Our study demonstrated that FMT, and, especially, FT-A potentiates the effects of a moderate CR on weight loss and adiposity in the short term, by decreasing feed efficiency and increasing adipose tissue lipolysis. Although FT-A produced a significant increase in bacterial richness/diversity, FMT did not significantly modify gut microbiota composition compared to the CR at phyla and bacteria genera levels, and only significant increases in Bifidobacterium and Blautia genera were observed. These results could suggest that other mechanisms different from bacterial microbiota engraftment participates in these beneficial effects. Thus, FT-A represents a very positive synergetic approach for obese patients that do not respond well to moderate restrictive diets.

Lyophilized Probiotic Lactic Acid Bacteria Viability in Potato Chips and Its Impact on Oil Oxidation

To produce a new probiotic-containing food product, potato chips, as the most preferred fast food, were chosen. Preferably, it should be preserved for a long period without oxidation. The presented study aimed to compare potato chips containing two lyophilized probiotic lactic acid bacteria (Bifidobacterium longum ATCC 15708 and Lactobacillus helveticus LH-B02) in order to retard lipid oxidation. Lyophilization of probiotics was carried out into two cryoprotective media-skim milk (SM) and gelatin/glycerol (GG) as lactose-free medium. Results revealed that GG and SM media were the most suitable for lyophilization of B. longum and L. helveticus, respectively. . The lyophilized live cells were incorporated in potato chips, packed and their effect on oil oxidation was assessed. . Results showed that the lyophilized B. longum in SM remained alive at 6.5 log CFU/g for 4 months at 30 °C. Interestingly, potato chip bags containing B. longum lyophilized in SM medium exhibited a decrease in peroxide value (PV) and acid value (AV) of the extracted oil by 40.13% and 25%, respectively, compared to the control bags. The created probiotic potato chips containing B. longum fulfill the criteria of the probiotic product besides the prime quality and sensory attributes.

Considering gut microbiota in treatment of type 2 diabetes mellitus

Advances in the understanding of the pathogenesis of type 2 diabetes mellitus (T2D) have revealed a role for gut microbiota dysbiosis in driving this disease. This suggests the possibility that approaches to restore a healthy host-microbiota relationship might be a means of ameliorating T2D. Indeed, recent studies indicate that many currently used treatments for T2D are reported to impact gut microbiota composition. Such changes in gut microbiota may mediate and/or reflect the efficacy of these interventions. This article outlines the rationale for considering the microbiota as a central determent of development of T2D and, moreover, reviews evidence that impacting microbiota might be germane to amelioration of T2D, both in terms of understanding mechanisms that mediate efficacy of exiting T2D therapies and in developing novel treatments for this disorder.

Bifidobacterium pseudolongum reduces triglycerides by modulating gut microbiota in mice fed high-fat food

Obesity has become a growing concern around the world. The purpose of this study was to investigate the potential benefit of Bifidobacterium pseudolongum (B. pseudolongum) on obesity, gut microbiota, and its physiological mechanism. The obese mice model was established with a high-fat diet (HFD), and the treatment were used the strain B. pseudolongum. We investigated the changes in fat content, plasma metabolites and gut microbiota on obese mice and B. pseudolongum treated obese mice. We found that B. pseudolongum treatment significantly decreased the body mass (about 12 %), plasma triglycerides (about 12.4 %), gross energy intake (about 12.8 %), and visceral fat (about 26.5 %) in obese mice. Further, High-throughput pyrosequencing of the 16S rRNA demonstrated that B. pseudolongum treatment markedly recovered the gut microbiota dysbiosis in obese mice, including the diversity of microbiota and the ratio of Firmicutes to Bacteroidetes. B. pseudolongum treatment increased the abundance of the bacterial genus Butyricimonas and Bifidobacterium. Therefore, B. pseudolongum may have therapeutic potential for the treatment of diet-induced obesity (DIO). B. pseudolongum treatment could change host gut microbiota and provide benefits to host digestive processes that mitigate metabolic diseases.

Microbial dysbiosis-induced obesity: role of gut microbiota in homoeostasis of energy metabolism

The global obesity epidemic has necessitated the search for better intervention strategies including the exploitation of the health benefits of some gut microbiota and their metabolic products. Therefore, we examined the gut microbial composition and mechanisms of interaction with the host in relation to homoeostatic energy metabolism and pathophysiology of dysbiosis-induced metabolic inflammation and obesity. We also discussed the eubiotic, health-promoting effects of probiotics and prebiotics as well as epigenetic modifications associated with gut microbial dysbiosis and risk of obesity. High-fat/carbohydrate diet programmes the gut microbiota to one predominated by Firmicutes (Clostridium), Prevotella and Methanobrevibacter but deficient in beneficial genera/species such as Bacteroides, Bifidobacterium, Lactobacillus and Akkermansia. Altered gut microbiota is associated with decreased expression of SCFA that maintain intestinal epithelial barrier integrity, reduce bacterial translocation and inflammation and increase expression of hunger-suppressing hormones. Reduced amounts of beneficial micro-organisms also inhibit fasting-induced adipocyte factor expression leading to dyslipidaemia. A low-grade chronic inflammation (metabolic endotoxaemia) ensues which culminates in obesity and its co-morbidities. The synergy of high-fat diet and dysbiotic gut microbiota initiates a recipe that epigenetically programmes the host for increased adiposity and poor glycaemic control. Interestingly, these obesogenic mechanistic pathways that are transmittable from one generation to another can be modulated through the administration of probiotics, prebiotics and synbiotics. Though the influence of gut microbiota on the risk of obesity and several intervention strategies have been extensively demonstrated in animal models, application in humans still requires further robust investigation.

Salivary Microbiological and Gingival Health Status Evaluation of Adolescents With Overweight and Obesity: A Cluster Analysis

Given the high prevalence of obesity in children and adolescents, the investigation of early markers is of clinical importance to better manage this condition. Thus, the aim was to evaluate the cross-sectional relationship between salivary microbiota, gingival health status, and excess weight in adolescents. A total of 248 students (14-17 y; 119 girls) were included, free of caries lesions and periodontal pockets. Physical examination included measures of height, weight, and body fat percentage (%BF). Oral examination was performed to gather information on dental (DMFT index) and gingival health status. Unstimulated saliva was submitted to qPCR reactions to quantify Streptococcus mutans, Porphyromonas gingivalis, Bifidobacteria, and Streptococcus pneumoniae percentages and the NFKappaB expression. Two-way ANOVA was applied considering group (normal-weight/overweight/obesity) and sex factors, in addition to cluster analysis. Group effect was significant for %S. mutans (partial eta² = 0.20; p < 0.001) and %Bifidobacteria (partial eta² = 0.19; p < 0.001), with overweight and obesity groups showing the highest levels compared to normal-weight ones, with no significant sex effect. There was no difference in the frequency of gingivitis, P. gingivalis, and S. pneumoniae percentages or NFKappaB expression between groups. Cluster analysis generated three clusters according to body fat accumulation: "Higher %BF," "Moderate %BF," and "Lower %BF." "Higher %BF" cluster was characterized by higher body fat percentage and higher salivary %Bifidobacteria, while cluster "Lower %BF" was characterized by lower body fat percentage and lower frequency of gingivitis ("Moderate %BF" cluster was the contrast). According to nutritional status, a difference in salivary S. mutans and Bifidobacteria percentages was found, with overweight or obesity adolescents showing the highest percentages than normal-weight ones. Besides, a positive relationship between body fat accumulation and Bifidobacteria count was observed, indicating a possible interaction between oral bacteria communities and weight gain.

Gastrointestinal Helminth Infection Improves Insulin Sensitivity, Decreases Systemic Inflammation, and Alters the Composition of Gut Microbiota in Distinct Mouse Models of Type 2 Diabetes

Type 2 diabetes (T2D) is a major health problem and is considered one of the top 10 diseases leading to death globally. T2D has been widely associated with systemic and local inflammatory responses and with alterations in the gut microbiota. Microorganisms, including parasitic worms and gut microbes have exquisitely co-evolved with their hosts to establish an immunological interaction that is essential for the formation and maintenance of a balanced immune system, including suppression of excessive inflammation. Herein we show that both prophylactic and therapeutic infection of mice with the parasitic hookworm-like nematode, Nippostrongylus brasiliensis, significantly reduced fasting blood glucose, oral glucose tolerance and body weight gain in two different diet-induced mouse models of T2D. Helminth infection was associated with elevated type 2 immune responses including increased eosinophil numbers in the mesenteric lymph nodes, liver and adipose tissues, as well as increased expression of IL-4 and alternatively activated macrophage marker genes in adipose tissue, liver and gut. N. brasiliensis infection was also associated with significant compositional changes in the gut microbiota at both the phylum and order levels. Our findings show that N. brasiliensis infection drives changes in local and systemic immune cell populations, and that these changes are associated with a reduction in systemic and local inflammation and compositional changes in the gut microbiota which cumulatively might be responsible for the improved insulin sensitivity observed in infected mice. Our findings indicate that carefully controlled therapeutic hookworm infection in humans could be a novel approach for treating metabolic syndrome and thereby preventing T2D.

Childhood obesity: an overview of laboratory medicine, exercise and microbiome

In the last few years, a significant increase of childhood obesity incidence unequally distributed within countries and population groups has been observed, thus representing an important public health problem associated with several health and social consequences. Obese children have more than a 50% probability of becoming obese adults, and to develop pathologies typical of obese adults, that include type 2-diabetes, dyslipidemia and hypertension. Also environmental factors, such as reduced physical activity and increased sedentary activities, may also result in increased caloric intake and/or decreased caloric expenditure. In the present review, we aimed to identify and describe a specific panel of parameters in order to evaluate and characterize the childhood obesity status useful in setting up a preventive diagnostic approach directed at improving health-related behaviors and identifying predisposing risk factors. An early identification of risk factors for childhood obesity could definitely help in setting up adequate and specific clinical treatments.

More than an Anti-diabetic Bariatric Surgery, Metabolic Surgery Alleviates Systemic and Local Inflammation in Obesity

Obesity, associated with increased risk of type 2 diabetes (T2D), cardiovascular disease, and hepatic steatosis et al., has become a major global health problem. Recently, obesity has been proven to be under a status of low-grade, chronic inflammation, which contributes to insulin resistance and T2D. Bariatric surgery is currently an effective treatment for the control of morbid obesity and T2D, which impels ongoing efforts to clarify physiological and molecular mechanisms mediating these benefits. The correlation between obesity, inflammation, and T2D has been revealed to a certain extent, and studies have shed light on the effect of bariatric surgery on inflammatory status of subjects with obesity. Based on recent findings, this review focuses on the relationship between inflammation, obesity, and bariatric surgery.

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.

Effects of probiotic supplementation on the regulation of blood lipid levels in overweight or obese subjects: a meta-analysis

BACKGROUND

Obesity is a risk factor for many deadly diseases. Meanwhile, the prevalence of obesity has been continuously increasing in many countries. Probiotics are defined as live microorganisms that confer health benefits on hosts. Probiotic supplementation could reduce body weight, body mass index (BMI) and fat percentage. However, it is unclear whether supplementation with probiotics is beneficial to lower blood lipid levels for obese or overweight people.

METHODS

In this study, a comprehensive search across multiple databases was performed to identify studies that focused on the effects of probiotics on blood lipid levels in overweight or obese subjects. The meta-analysis included studies that compared the variations in blood lipid (total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL) and triglyceride (TG)) concentrations between overweight and obese subjects who were supplemented with probiotics versus the controls who were not supplemented with probiotics.

RESULTS

Our findings indicated that probiotic supplementation in obese or overweight people was associated with significantly larger reductions in TC and LDL levels compared to a lack of probiotic supplementation in the control subjects. However, there was no significant difference in the variations between HDL and TG concentrations.

CONCLUSION

Probiotic supplementation reduced TC and LDL concentrations in obese or overweight people. Additional data from large clinical trials are required to confirm the efficacy and safety of probiotics in the regulation of blood lipid levels in obese or overweight people.

Dietary Fiber in Bilberry Ameliorates Pre-Obesity Events in Rats by Regulating Lipid Depot, Cecal Short-Chain Fatty Acid Formation and Microbiota Composition

Obesity is linked to non-alcoholic fatty liver disease and risk factors associated to metabolic syndrome. Bilberry (Vaccinium myrtillus) that contains easily fermentable fiber may strengthen the intestinal barrier function, attenuate inflammation and modulate gut microbiota composition, thereby prevent obesity development. In the current study, liver lipid metabolism, fat depot, cecal and serum short-chain fatty acids (SCFAs) and gut microbiome were evaluated in rats fed bilberries in a high-fat (HFD + BB) or low-fat (LFD + BB) setting for 8 weeks and compared with diets containing equal amount of fiber resistant to fermentation (cellulose, HFD and LFD). HFD fed rats did not obtain an obese phenotype but underwent pre-obesity events including increased liver index, lipid accumulation and increased serum cholesterol levels. This was linked to shifts of cecal bacterial community and reduction of major SCFAs. Bilberry inclusion improved liver metabolism and serum lipid levels. Bilberry inclusion under either LFD or HFD, maintained microbiota homeostasis, stimulated interscapular-brown adipose tissue depot associated with increased mRNA expression of uncoupling protein-1; enhanced SCFAs in the cecum and circulation; and promoted butyric acid and butyrate-producing bacteria. These findings suggest that bilberry may serve as a preventative dietary measure to optimize microbiome and associated lipid metabolism during or prior to HFD.

The gut microbiota influences anticancer immunosurveillance and general health

Discoveries made in the past 5 years indicate that the composition of the intestinal microbiota has a major influence on the effectiveness of anticancer immunosurveillance and thereby contributes to the therapeutic activity of immune-checkpoint inhibitors that target cytotoxic T lymphocyte protein 4 (CTLA-4) or the programmed cell death protein 1 (PD-1)-programmed cell death 1 ligand 1 (PD-L1) axis, as well as the activity of immunogenic chemotherapies. Herein, we highlight some of the bacteria, such as Akkermansia muciniphila, Bacteroides fragilis, Bifidobacterium spp. and Faecalibacterium spp., that have been associated with favourable anticancer immune responses in both preclinical tumour models and patients with cancer. Importantly, these bacteria also seem to have a positive influence on general health, thus reducing the incidence of metabolic disorders and a wide range of chronic inflammatory pathologies. We surmise that a diverse and propitious microbial ecosystem favours organismal homeostasis, particularly at the level of the cancer-immune dialogue.

Gut Microbiota in Alzheimer's Disease, Depression, and Type 2 Diabetes Mellitus: The Role of Oxidative Stress

Gut microbiota consists of over 100 trillion microorganisms including at least 1000 different species of bacteria and is crucially involved in physiological and pathophysiological processes occurring in the host. An imbalanced gastrointestinal ecosystem (dysbiosis) seems to be a contributor to the development and maintenance of several diseases, such as Alzheimer's disease, depression, and type 2 diabetes mellitus. Interestingly, the three disorders are frequently associated as demonstrated by the high comorbidity rates. In this review, we introduce gut microbiota and its role in both normal and pathological processes; then, we discuss the importance of the gut-brain axis as well as the role of oxidative stress and inflammation as mediators of the pathological processes in which dysbiosis is involved. Specific sections pertain the role of the altered gut microbiota in the pathogenesis of Alzheimer's disease, depression, and type 2 diabetes mellitus. The therapeutic implications of microbiota manipulation are briefly discussed. Finally, a conclusion comments on the possible role of dysbiosis as a common pathogenetic contributor (via oxidative stress and inflammation) shared by the three disorders.

Weight loss probiotic supplementation effect in overweight and obesity subjects: A review

Obese individuals present adverse changes in the diversity and composition of the gut microbiota, leading to alterations in energy balance, lipid metabolism, endocrine disturbances, and low-grade chronic systemic inflammation increases. Probiotic supplementation appears to change gut microbiota by decrease gut permeability, inflammation, and metabolic disorders, creating a promising environment to weight loss. This revision resumes the main findings of probiotic supplementation and weight loss that contributed to building the current background linking changes in gut microbiota profile and with obesity.

The Role of Probiotics and Prebiotics in the Prevention and Treatment of Obesity

Obesity is a global pandemic complex to treat due to its multifactorial pathogenesis-an unhealthy lifestyle, neuronal and hormonal mechanisms, and genetic and epigenetic factors are involved. Scientific evidence supports the idea that obesity and metabolic consequences are strongly related to changes in both the function and composition of gut microbiota, which exert an essential role in modulating energy metabolism. Modifications of gut microbiota composition have been associated with variations in body weight and body mass index. Lifestyle modifications remain as primary therapy for obesity and related metabolic disorders. New therapeutic strategies to treat/prevent obesity have been proposed, based on pre- and/or probiotic modulation of gut microbiota to mimic that found in healthy non-obese subjects. Based on human and animal studies, this review aimed to discuss mechanisms through which gut microbiota could act as a key modifier of obesity and related metabolic complications. Evidence from animal studies and human clinical trials suggesting potential beneficial effects of prebiotic and various probiotic strains on those physical, biochemical, and metabolic parameters related to obesity is presented. As a conclusion, a deeper knowledge about pre-/probiotic mechanisms of action, in combination with adequately powered, randomized controlled follow-up studies, will facilitate the clinical application and development of personalized healthcare strategies.

Letrozole treatment of adult female mice results in a similar reproductive phenotype but distinct changes in metabolism and the gut microbiome compared to pubertal mice

BACKGROUND

A majority of women with polycystic ovary syndrome (PCOS) have metabolic dysfunction that results in an increased risk of type 2 diabetes. We previously developed a pubertal mouse model using the aromatase inhibitor, letrozole, which recapitulates many of the reproductive and metabolic features of PCOS. To further our understanding of the effects of androgen excess, we compared the effects of letrozole treatment initiated in puberty versus adulthood on reproductive and metabolic phenotypes as well as on the gut microbiome.

RESULTS

Letrozole treatment of both pubertal and adult female mice resulted in reproductive hallmarks of PCOS, including hyperandrogenemia, anovulation and polycystic ovaries. However, unlike pubertal mice, treatment of adult female mice resulted in modest weight gain and abdominal adiposity, minimal elevation in fasting blood glucose and insulin levels, and no detectable insulin resistance. In addition, letrozole treatment of adult mice was associated with a distinct shift in gut microbial diversity compared to letrozole treatment of pubertal mice.

CONCLUSIONS

Our results indicate that dysregulation of metabolism and the gut microbiome in PCOS may be influenced by the timing of androgen exposure. In addition, the minimal weight gain and lack of insulin resistance in adult female mice after letrozole treatment indicates that this model may be useful for investigating the effects of hyperandrogenemia on the hypothalamic-pituitary-gonadal axis and the periphery without the influence of substantial metabolic dysregulation.

Probiotics: How Effective Are They in the Fight against Obesity?

Obesity has been associated with structural and functional changes in the gut microbiota. The abundance in, and diversity of, certain bacteria may favor energy harvest and metabolic pathways leading to obesity. Therefore, gut microbiota has become a potential target that can be manipulated to obtain optimal health. Probiotics have been shown to influence the composition of the gut microbiota, improve gut integrity, and restore the microbial shifts characteristic of obesity. Based on physical and biochemical parameters, metabolic and inflammatory markers, and alterations in gut microbe diversity, animal studies revealed beneficial results in obese models whereas the results in humans are sparse and inconsistent. Thus, the purpose of this review is to present evidence from animal studies and human clinical trials demonstrating the effects of various probiotic strains and their potential efficacy in improving obesity and associated metabolic dysfunctions. Furthermore, the review discusses current gaps in our understanding of how probiotics modulate gut microflora to protect against obesity. Finally, we propose future studies and methodological approaches that may shed light on the challenges facing the scientific community in deciphering the host–bacteria interaction in obesity.

Dietary quality of predominantly traditional diets is associated with blood glucose profiles, but not with total fecal Bifidobacterium in Indonesian women

Background

A high quality modern diet is associated with reduced risk of metabolic disease and diabetes. However, it remains unclear whether the quality of predominantly traditional ethnic diets is associated with such conditions. Moreover, the relationship between dietary quality and microbiota, a potential mediator of metabolic disease, has not been studied.

Objective

We investigated the relationship of dietary quality of traditional ethnic diets in Indonesia with fasting blood glucose (FBG), HbA1c, and the number of fecal Bifidobacterium.

Design

A cross-sectional study was conducted in selected districts with predominantly animal- or plant-based traditional diets of West Sumatera and West Java provinces, respectively. A total of 240 apparently healthy women aged 19–50 years were randomly selected from 360 women screened by a cluster sampling design. Dietary quality was assessed by 2-day repeated 24-hour food recall, and scored using the Healthy Eating Index (HEI) 2010. FBG was quantified with the enzymatic colorimetric method, and HbA1c by using hexokinase and high-performance liquid chromatography, and total fecal Bifidobacterium by real-time quantitative polymerase chain reaction.

Results

The HEI scores of 99% of women were <51, indicating a low-quality diet. In adjusted multivariate regression, HEI was inversely associated with FBG (ß = -0.403; 95% CI = -0.789 to -0.016; p = 0.041) and HbA1c (ß = -0.018; 95% CI = -0.036 to 0.000; p = 0.048) but was not significantly associated with total levels of Bifidobacterium (ß = -0.007, p = 0.275). Bifidobacterium count was not significantly associated with either FBG or HbA1c levels.

Conclusion

Low dietary quality is clearly associated with risk of increased markers of blood glucose. However, any mediating role of Bifidobacterium between dietary quality and glucose outcomes was not apparent. Innovative interventions for healthy eating should be implemented to increase dietary quality of populations transitioning from predominantly traditional to modern diets, to reduce the risk of diabetes, especially in women.

Diet-Independent Correlations between Bacteria and Dysfunction of Gut, Adipose Tissue, and Liver: A Comprehensive Microbiota Analysis in Feces and Mucosa of the Ileum and Colon in Obese Mice with NAFLD

Development of non-alcoholic fatty liver disease (NAFLD) is linked to obesity, adipose tissue inflammation, and gut dysfunction, all of which depend on diet. So far, studies have mainly focused on diet-related fecal microbiota changes, but other compartments may be more informative on host health. We present a first systematic analysis of microbiota changes in the ileum and colon using multiple diets and investigating both fecal and mucosal samples. Ldlr−/−.Leiden mice received one of three different energy-dense (ED)-diets (n = 15/group) for 15 weeks. All of the ED diets induced obesity and metabolic risk factors, altered short-chain fatty acids (SCFA), and increased gut permeability and NAFLD to various extents. ED diets reduced the diversity of high-abundant bacteria and increased the diversity of low-abundant bacteria in all of the gut compartments. The ED groups showed highly variable, partially overlapping microbiota compositions that differed significantly from chow. Correlation analyses demonstrated that (1) specific groups of bacteria correlate with metabolic risk factors, organ dysfunction, and NAFLD endpoints, (2) colon mucosa had greater predictive value than other compartments, (3) correlating bacteria differed per compartment, and (4) some bacteria correlated with plasma SCFA levels. In conclusion, this comprehensive microbiota analysis demonstrates correlations between the microbiota and dysfunctions of gut, adipose tissue, and liver, independent of a specific disease-inducing diet.

Therapeutic Microbiology: The Role of Bifidobacterium breve as Food Supplement for the Prevention/Treatment of Paediatric Diseases

The human intestinal microbiota, establishing a symbiotic relationship with the host, plays a significant role for human health. It is also well known that a disease status is frequently characterized by a dysbiotic condition of the gut microbiota. A probiotic treatment can represent an alternative therapy for enteric disorders and human pathologies not apparently linked to the gastrointestinal tract. Among bifidobacteria, strains of the species Bifidobacterium breve are widely used in paediatrics. B. breve is the dominant species in the gut of breast-fed infants and it has also been isolated from human milk. It has antimicrobial activity against human pathogens, it does not possess transmissible antibiotic resistance traits, it is not cytotoxic and it has immuno-stimulating abilities. This review describes the applications of B. breve strains mainly for the prevention/treatment of paediatric pathologies. The target pathologies range from widespread gut diseases, including diarrhoea and infant colics, to celiac disease, obesity, allergic and neurological disorders. Moreover, B. breve strains are used for the prevention of side infections in preterm newborns and during antibiotic treatments or chemotherapy. With this documentation, we hope to increase knowledge on this species to boost the interest in the emerging discipline known as "therapeutic microbiology".

Is It Time to Use Probiotics to Prevent or Treat Obesity?

In recent years, attention has been given to the role potentially played by gut microbiota in the development of obesity. Several studies have shown that in individuals with obesity, the gut microbiota composition can be significantly different from that of lean individuals, that faecal bacteria can exert a fundamental role in modulating energy metabolism, and that modifications of gut microbiota composition can be associated with increases or reductions of body weight and body mass index. Based on this evidence, manipulation of the gut microbiota with probiotics has been considered a possible method to prevent and treat obesity. However, despite a great amount of data, the use of probiotics to prevent and treat obesity and related problems remains debated. Studies have found that the probiotic effect on body weight and metabolism is strain specific and that only some of the species included in the Lactobacillus and Bifidobacterium genera are effective, whereas the use of other strains can be deleterious. However, the dosage, duration of administration, and long-term effects of probiotics administration to prevent overweight and obesity are not known. Further studies are needed before probiotics can be rationally prescribed for the prevention or treatment of obesity. Control of the diet and environmental and life-style factors that favour obesity development remain the best solution to problems related to weight gain.

A Comparative Study of Serum Biochemistry, Metabolome and Microbiome Parameters of Clinically Healthy, Normal Weight, Overweight, and Obese Companion Dogs

The aim of this study was to compare fecal microbiome, plasma, fecal and urine metabolomes, and serum biochemistry of adult companion dogs according to body condition scores. Blood, serum/plasma, urine, and fecal samples were collected from 66 clinically healthy, adult companion dogs of either normal weight (NW), overweight (OW), or obese dogs (OB). analyses included fecal microbiome analyses via 16S ribosomal RNA gene amplicon; sequencing, nontargeted plasma, fecal, and urine metabolomics using liquid chromatography/gas chromatography-mass; spectrometry, and serum biochemistry for each dog. Few significant differences in serum biochemistry and fecal microbiome Operational Taxonomic Unit (OTU) were found between weight groups and there was high OTU variation between individual dogs. NW dogs had higher relative abundance of the genus Eubacterium (log-fold change 4.3, adjusted P value = .003) and lower relative abundance of the family Bifidobacteriaceae (log-fold change -3.6, adjusted P value = .02) compared to OB dogs. The microbiome of NW dogs had higher OTU richness compared with OB dogs. Metabolome analysis showed 185 plasma, 37 fecal, and 45 urine metabolites that significantly differed between NW and OW or OB dogs. There were notable significant differences in relative abundance of several plasma phospholipid moieties and fecal volatile fatty acids between weight phenotypes. The combinations of host and gut microbiota and metabolic shifts suggest a pattern that could help detection of early metabolic changes in overweight dogs before the development of obesity related disease. The results of this study support the need for continued investigation into sensitive measures of metabolic aberrancies in overweight dogs.

A two-stage microbial association mapping framework with advanced FDR control

BACKGROUND

In microbiome studies, it is important to detect taxa which are associated with pathological outcomes at the lowest definable taxonomic rank, such as genus or species. Traditionally, taxa at the target rank are tested for individual association, followed by the Benjamini-Hochberg (BH) procedure to control for false discovery rate (FDR). However, this approach neglects the dependence structure among taxa and may lead to conservative results. The taxonomic tree of microbiome data represents alignment from phylum to species rank and characterizes evolutionary relationships across microbial taxa. Taxa that are closer on the tree usually have similar responses to the exposure (environment). The statistical power in microbial association tests can be enhanced by efficiently employing the prior evolutionary information via the taxonomic tree.

METHODS

We propose a two-stage microbial association mapping framework (massMap) which uses grouping information from the taxonomic tree to strengthen statistical power in association tests at the target rank. massMap first screens the association of taxonomic groups at a pre-selected higher taxonomic rank using a powerful microbial group test OMiAT. The method then proceeds to test the association for each candidate taxon at the target rank within the significant taxonomic groups identified in the first stage. Hierarchical BH (HBH) and selected subset testing (SST) procedures are evaluated to control the FDR for the two-stage structured tests.

RESULTS

Our simulations show that massMap incorporating OMiAT and the advanced FDR controlling methodologies largely alleviates the multiplicity issue. It is statistically more powerful than the traditional association mapping directly at the target rank while controlling the FDR at desired levels under most scenarios. In our real data analyses, massMap detects more or the same amount of associated species with smaller adjusted p values compared to the traditional method, which further illustrates the efficiency of the proposed framework. The R package of massMap is publicly available at https://sites.google.com/site/huilinli09/software and https://github.com/JiyuanHu/ .

CONCLUSIONS

massMap is a novel microbial association mapping framework and achieves additional efficiency by utilizing the intrinsic taxonomic structure of microbiome data.

Anti-obesity properties of the strain Bifidobacterium animalis subsp. lactis CECT 8145 in Zücker fatty rats

We evaluated the effect of oral administration of Bifidobacterium animalis subsp. lactis CECT 8145 strain in Zücker fatty rats. The Zücker fatty rats were randomly divided into two groups (n=10 each) and administered either B. animalis subsp. lactis CECT 8145 (1010 cfu/day) suspended in skim milk, or skim milk alone (control group). Each treatment was administered in drinking bottles from week 5 until week 17 of age. A lean Zücker rat group (standard group) was included to provide normal values for the Zücker strain. This group was administered skim milk in the drinking bottle for the same experimental period as Zücker fatty rats. Body weight gain was greater in the fatty control group than in the fatty rats treated daily with B. animalis subsp. lactis CECT 8145. Furthermore, dry and liquid food intake significantly decreased in the treated Zücker fatty group and these rats also showed decreased plasma ghrelin levels as compared with the Zücker fatty control group. B. animalis subsp. lactis CECT 8145 intake also decreased plasma tumour necrosis factor-α (a proinflammatory cytokine) and plasma malondialdehyde (a biomarker of oxidative stress). Moreover, the ratio plasma total cholesterol/plasma cholesterol transported by high-density lipoproteins, considered as an index for cardiovascular disease, also significantly decreased in the Zücker fatty rats treated with B. animalis subsp. lactis CECT 8145. By contrast, this bacterial strain significantly increased plasma adiponectin (an insulin-sensitising adipokine), but did not produce significant effects on triglyceride levels or glucose metabolism biomarkers. Although further research is required to confirm B. animalis subsp. lactis CECT 8145 is an efficient anti-obesity treatment in humans, the results obtained in this study are promising and point to the health and anti-obesity properties of this bacterial strain.

The development of probiotics therapy to obesity: a therapy that has gained considerable momentum

Obesity is a growing epidemic worldwide. The most frequent cause leading to the development of obesity is an imbalance between energy intake and energy expenditure. The gut microbiota is an environmental factor involved in obesity and metabolic disorders which reveals that obese animal and human subjects present alterations in the composition of the gut microbiota compared to their lean counterparts. Furthermore, evidence has so far demonstrated that the gut microbiota, which influences whole-body metabolism, by affecting energy balance, but also inflammation and gut barrier function, integrates peripheral and central food intake regulatory signals, thereby altering body weight. At the same time, these data suggest that species of intestinal commensal bacteria may play either a pathogenic or a protective role in the development of obesity. Though still a relatively nascent field of research, evidence to date suggests that manipulating the gut microbiome may represent effective treatment for the prevention or management of obesity. Various studies have described the beneficial effects of specific bacteria on the characteristics of obesity. However, the available data in this field remain limited and the relevant scientific work has only recently begun. This review aims to summarize the notable advances and contributions in the field that may prove useful for identifying probiotics that target obesity and its related disorders.

Influence of the microbiota and probiotics in obesity

Gut microbiota plays a key role in the control of body weight. In the present review the different ways in which it can modify the energy homeostasis of the host are exposed, based on its capacity to modify the metabolism of the individual and its contribution in the energy consumption regulation. With the current evidence, it is not clear what microbiota profile is associated with the presence of obesity, although in animal models it seems to be related to a higher proportion of bacteria of the Firmicutes phylum, to the detriment of those of the Bacteroidetes phylum. Other factors clearly involved would be the diversity in the gut microbiota or its possible functional changes. More studies in humans are needed to clarify how dysbiosis can influence weight control. On the other hand, probiotics directly affect the gut microbiota, modulating its composition and, possibly, its functionality. A large number of studies in humans have evaluated the impact of probiotics on obesity. Although this intervention may have a potentially beneficial effect, more effort is needed to clarify which strains of probiotics should be recommended, at what dose and for how long.

The human gut microbiota: Metabolism and perspective in obesity

The gut microbiota has been recognized as an important factor in the development of metabolic diseases such as obesity and is considered an endocrine organ involved in the maintenance of energy homeostasis and host immunity. Dysbiosis can change the functioning of the intestinal barrier and the gut-associated lymphoid tissues (GALT) by allowing the passage of structural components of bacteria, such as lipopolysaccharides (LPS), which activate inflammatory pathways that may contribute to the development of insulin resistance. Furthermore, intestinal dysbiosis can alter the production of gastrointestinal peptides related to satiety, resulting in an increased food intake. In obese people, this dysbiosis seems be related to increases of the phylum Firmicutes, the genus Clostridium, and the species Eubacterium rectale, Clostridium coccoides, Lactobacillus reuteri, Akkermansia muciniphila, Clostridium histolyticum, and Staphylococcus aureus.

Gut Microbiota: From Microorganisms to Metabolic Organ Influencing Obesity

OBJECTIVE

This review summarizes the current understanding of the relationship between gut microbiota and the host as it pertains to the regulation of energy balance and obesity.

METHODS

The paper begins with a brief description of the gut microbiota environment, distribution, and its unique symbiotic relationship with the host. The way that enviromental factors influence microbiota composition and subsequent impact on the host are then described. Next, the mechanisms linking gut dysbiosis with obesity are discussed, and finally current challenges and limitations in understanding the role of gut microbiota in control of obesity are presented.

RESULTS

Gut microbiota has been implicated in regulation of fat storage, as well as gut dysbiosis, thus contributing to the development of obesity, insulin resistance, hyperglycemia and hyperlipidemia. However, the underlying mechanisms of these processes are far from being clear and will require complex preclinical and clinical interdisciplinary studies of bacteria and host cell-to-cell interactions.

CONCLUSIONS

There is a need for a better understanding of how changes in gut microbiota composition can impact energy balance and thus control weight gain. This may represent a promising avenue in the race to develop nonsurgical treatments for obesity.

The gut microbiota and its potential role in obesity

The human GI tract harbors a diverse and dynamic microbial community comprising bacteria, archaea, viruses and eukaryotic microbes, which varies in composition from individual to individual. A healthy microbiota metabolizes various indigestible dietary components of the host, maintains host immune homeostasis and nutrient intake, but, an imbalanced microbiota has been reported to be associated with many diseases, including obesity. Rodent studies have produced evidence in support of the causal role of the gut microbiota in the development of obesity, however, such causal relationship is lacking in humans. The objective of this review is to critically analyze the vast information available on the composition, function and alterations of the gut microbiota in obesity and explore the future prospects of this research area.

Health Effects and Sources of Prebiotic Dietary Fiber

Prebiotic dietary fibers act as carbon sources for primary and secondary fermentation pathways in the colon, and support digestive health in many ways. Fructooligosaccharides, inulin, and galactooligosaccharides are universally agreed-upon prebiotics. The objective of this paper is to summarize the 8 most prominent health benefits of prebiotic dietary fibers that are due to their fermentability by colonic microbiota, as well as summarize the 8 categories of prebiotic dietary fibers that support these health benefits. Although not all categories exhibit similar effects in human studies, all of these categories promote digestive health due to their fermentability. Scientific and regulatory definitions of prebiotics differ greatly, although health benefits of these compounds are uniformly agreed upon to be due to their fermentability by gut microbiota. Scientific evidence suggests that 8 categories of compounds all exhibit health benefits related to their metabolism by colonic taxa.

Bifidobacteria and its rice fermented products on diet induced obese mice: analysis of physical status, serum profile and gene expressions

Obesity is highly correlated with the dysbiosis of intestinal microbiota, and bifidobacteria are one of the soft targets of this metabolic syndrome. The aim of this study is to evaluate the efficacy of Bifidobacterium sp. MKK4 and rice-based fermented foods on physical, haematological, gut microbiota and lypogenic-lypolytic marker genes in diet-induced obese mice. Adult male mice (21±0.7 g) were randomly divided into four groups (n=10) according to the type of diet: normal diet (ND), high fat diet (HFD), HFD supplemented with Bifidobacterium sp. MKK4 and HFD supplemented with MKK4 associated rice-fermented food. 8 weeks of bacterial therapy in the obese mice resulted in significant reduction of body and organ weights, improved serum levels of glucose, triglyceride and cholesterol, the histological structure of the liver (steatosis), and re-establishment of gut Lactobacillus, Bifidobacterium and Bacteroides species. The bacterial therapy led to up-regulation of lipolytic transcription factors, such as peroxisome proliferator-activated receptor (PPAR)-α, PPAR-δ, and their regulated gene products in fatty acid metabolism and glucose uptake, such as acyl-CoA oxidase, carnitine palmitoyl-transferase-1, uncoupling protein-3 and glucose transporter-4. Concomitantly, both adipocytogenesis and fatty acid synthesis were arrested as reflected by the down-regulation of sterol regulatory element binding protein-1c, acetyl-CoA carboxylase, fatty acid synthase and tumour necrosis factor alpha genes. The effectiveness of the fermented product was more profound than the single bacterium. These data provide experimental support with regard to the use of Bifidobacterium sp. MKK4 as a natural therapeutic agent to control obesity.