The gut microbiota and its potential role in obesity

Insulinemic potential of lifestyle is associated with depression and anxiety in adults: A large community-based study

BACKGROUND

We aimed to investigate the association between an empirical lifestyle index for hyperinsulinemia (ELIH), empirical lifestyle index for insulin resistance (ELIR), and depression and anxiety in an adult Iranian population.

METHODS

In this cross-sectional study, a total of 6450 participants, aged 35-65 years were recruited as part of the MASHAD cohort study. Dietary intakes were assessed using a validated food frequency questionnaire (FFQ). Depression and anxiety were screened using Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI). ELIH and ELIR were calculated using dietary intake, body mass index, and physical activity information. Multivariable ordinal logistic regression models were applied to determine the association between ELIH, ELIR, and depression and anxiety severity.

RESULTS

In a fully adjusted model, participants with the highest ELIH quartile had a higher odds of more severe depression and anxiety compared to those in the lowest category (OR = 1.44; 95 % CI = 1.22-1.71 and OR = 1.62; 95 % CI = 1.37-1.25, respectively). Participants with the highest ELIR had higher odds of more severe depression and anxiety compared to those in the lowest category (OR = 1.22; 95 % CI = 1.04-1.43 and OR = 1.21; 95 % CI = 1.03-1.42, respectively).

LIMITATIONS

The assessment of dietary intake and mental health by questionnaires may increases the rate of misclassification. Due to the study's cross-sectional nature, causal relationships cannot be established.

CONCLUSION

There was a significant positive association between the hyperinsulinemia and insulin resistance potential of lifestyle and severity of depression and anxiety among Iranian adults.

The Effects of Oral Probiotic Supplementation in Postmenopausal Women with Overweight and Obesity: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Gut microbiota has been identified as a unique endocrine organ linked to the development of cardiovascular disease and other illnesses, especially deteriorated in overweight and obese postmenopausal women. The object of this systematic review and meta-analysis aimed to assess the effects of oral supplementation with probiotics for overweight and obese postmenopausal women. We performed a systematic search for randomized controlled trials (RCTs) from inception to April 2022 in MEDLINE, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov. We also performed a hand search by reviewing reference lists to identify trials. The risk of bias in individual studies was assessed with the Cochrane risk of bias tool for randomized trials (RoB). Two reviewers independently selected studies and collected data. There were 6 studies from 5 RCTs with 281 participants in this systematic review. Compared with the placebo, the probiotics supplementation group had reductions in insulin (MD - 4.20 IU/L (95% CI - 8.11 to - 0.30 IU/L), I2 = 54%), HOMA-IR (MD - 1.25 (95% CI - 2.49 to - 0.01), I2 = 50%), and TNF-α (MD - 0.12 pg/mL (95% CI - 0.22 to - 0.01 pg/mL), I2 = 44%). Improvements were also shown in body adiposity and lipid profile, but these effects were nonsignificant. In addition to body adiposity and cardiovascular risk markers, one trial showed the administration of probiotics also had an effect on iron metabolism. In conclusion, probiotics have a potential benefit on glucose metabolism and inflammatory process in overweight and obese postmenopausal women, but this effect is mild. It demonstrates that oral probiotics supplementation can be a complementary treatment for improving the fitness of postmenopausal women with overweight and obesity.

Comparative analysis of changes in diarrhea and gut microbiota in Beigang pigs

Increasing evidence indicated that the gut microbiota is a large and complex organic combination, which is closely related to the host health. Diarrhea is a disease with devastating effects on livestock that has been demonstrated to be associated with gut microbiota. Currently, studies on gut microbiota and diarrhea have involved multiple species, but changes in gut microbiota of Beigang pigs during diarrhea have not been characterized. Here, we described gut microbial changes of Beigang pigs during diarrhea. Results indicated that a total of 4423 OTUs were recognized in diarrheic and healthy Beigang pigs, and Firmicutes and Bacteroidota were the most dominant phyla regardless of health status. However, the major components of the gut microbiota changed between diarrheic and healthy Beigang pigs. Bacterial taxonomic analysis revealed that the relative abundances of 3 phyla (Synergistota, Actinobacteriota and Spirochaetota) and 30 genera increased significantly during diarrhea, whereas the relative abundances of 3 phyla (Patescibacteria, Bacteroidota and Fibrobacterota) and 41 genera decreased significantly. In conclusion, this study found significant changes in the gut microbiota of Beigang pigs during diarrhea. Meanwhile, this also lays the foundation for the prevention and treatment of diarrhea in Beigang pigs and the further discovery of more anti-diarrhea probiotics.

Prebiotic effects of plant-derived (poly)phenols on host metabolism: Is there a role for short-chain fatty acids?

The gut microbiota has been extensively investigated during the last decade because of its effects on host neuroendocrine pathways and other processes. The imbalance between beneficial and pathogenic bacteria, known as dysbiosis, may be a determining predisposing factor for many noncommunicable chronic diseases, such as obesity, type 2 diabetes mellitus, metabolic syndrome, and Alzheimer's disease. On the other hand, interventions aiming to reestablish the balance between microbiota components have been suggested as potential preventive therapeutic strategies against these disorders. Among these interventions, dietary supplementation with (poly)phenols has been highlighted due to the modulatory effects exerted by those compounds on the gut microbiota. In addition, (poly)phenol consumption is associated with increased production of short-chain fatty acids (SCFAs), a set of microbial metabolites whose actions are ascribed to improving the abovementioned metabolic disorders. Thus, this review discusses the modulation of the gut microbiota by prebiotic (poly)phenols based on in vivo studies performed with isolated (poly)phenolic compounds, their interaction with the gut microbiota and the production of SCFAs in pursuit of the molecular mechanisms underlying the health effects of (poly)phenols on host metabolism.

Antiobesity Effects of Lactobacillus paracasei Subsp. paracasei, L. casei 431 on High-Fat Diet-Induced Obese Rats

Obesity is currently regarded as a global concern, and the key objectives of the global health strategy include its prevention and control. Probiotic supplementation can help achieve these objectives. This study aimed to assess whether a probiotic strain Lactobacillus paracasei ssp. paracasei, Lactobacillus casei 431 (henceforth, L. casei 431) possesses antiobesogenic properties. High-fat diet-induced obese Sprague-Dawley rats were treated with L. casei 431 for 10 weeks, and the outcomes were compared with those of rats treated with the antiobesity medication orlistat. Body weights, epididymal fat, and tissues from mice were assessed. Furthermore, serological and histological analyses were performed. Epididymal fat accumulation was significantly reduced in groups administered L. casei 431 and orlistat. Furthermore, L. casei 431 and orlistat treatments lowered serum alanine transaminase, aspartate aminotransferase, and triglyceride (TG) levels. Hematoxylin and eosin staining of the liver and epididymal adipose tissues showed that the L. casei 431-treated groups exhibited reduced lipid buildup and adipocyte size. Furthermore, sterol regulatory element-binding protein 1c, adipose TG lipase, and lipoprotein lipase messenger RNA (mRNA) levels were upregulated, leading to lipid oxidation and degradation, in L. casei 431-supplemented groups. Furthermore, carnitine palmitoyltransferase 1, a major factor in lipolysis, was consistently upregulated at the protein level after L. casei 431 administration. Collectively, these results demonstrate the potential of L. casei 431 in alleviating obesity in rats through optimizing lipid metabolism and some related biomarkers.

Changes in gut microbiota and short-chain fatty acids are involved in the process of canine obesity after neutering

Neutering is a significant risk factor for obesity in dogs. Changes in gut microbiota and its metabolites have been identified as a key player during obesity progression. However, the mechanisms that promote neuter-associated weight gain are not well understood. Therefore, in this study, sixteen clinically healthy Beagle dogs (6 male and 10 female, mean age = 8.22 ± 0.25 mo old) were neutered. Body weight (BW) and body condition score (BCS) were recorded at 1 d before neutering, 3, 6, 10, 16, and 21 mo after neutering. Dogs were grouped based on their BCS as ideal weight group (IW, n = 4, mean BW = 13.22 ± 1.30 kg, mean BCS = 5.00 ± 0.41) and obese group (OB, n = 12, mean BW = 18.57 ± 1.08 kg, mean BCS = 7.92 ± 0.82) at 21 mo after neutering. Serum lipid profile, glucose, and hormones and fecal microbiota and short-chain fatty acids (SCFAs) were measured. Our results showed that OB dogs had greater (P < 0.0001) BW (18.57 vs. 13.22 kg), BCS (7.92 vs. 5.00), and average daily gain (12.27 vs. 5.69 g/d) than IW dogs at 21 mo after neutering, and the obesity rate was up to 60%. In addition, significant increases (P < 0.05) in serum triglyceride (TG, 1.10 vs. 0.56 mmol/L) and high-density lipoprotein cholesterol (HDL-C, 6.96 vs. 5.40 mmol/L) levels and a significant decrease (P < 0.05) in serum adiponectin (APN, 54.06 vs. 58.39 μg/L) level were observed in OB dogs; serum total cholesterol (4.83 vs. 3.75 mmol/L) (P = 0.075) and leptin (LEP, 2.82 vs. 2.53 μg/L) (P = 0.065) levels tended to be greater in OB dogs; there was a trend towards a lower (P = 0.092) APN/LEP (19.32 vs. 21.81) in OB dogs. Results of fecal microbial alpha-diversity showed that Observed_species and Chao1 indices tended to be lower (P = 0.069) in OB dogs. The STAMP and LEfSe analyses revealed that OB dogs had a greater (P < 0.05 and LDA > 2) reduction in relative abundances of Bacteroides, Prevotella_9, and Megamonas than IW dogs. In addition, OB dogs also had greater (P < 0.05) reduction in fecal acetate, propionate, and butyrate concentrations than IW dogs. Moreover, clear negative correlations (|r| > 0.5 and P < 0.05) were found between SCFAs-producing bacteria and BW, TG, and HDL-C. The functional predictions of microbial communities based on PICRUSt2 analysis revealed that lipid metabolism and endocrine system were significantly disturbed in obese dogs after neutering. Thus, intervention with SCFAs-producing bacteria might represent a new target for the prevention or treatment of canine obesity after neutering. Moreover, weight control before neutering may also contribute to the prevention of canine obesity after neutering.

Effect of Intermittent Fasting, Probiotic-Fermented Camel Milk, and Probiotic-Fermented Camel Milk Incorporating Sukkari Date on Diet-Induced Obesity in Rats

Obesity causes metabolic syndrome disorders that are detrimental to health. The current study examined the effects of intermittent fasting (IF), fermented camel milk (FCM), and fermented camel milk incorporating 10% Sukkari date (FCM-D) on weight loss, blood profile, and antioxidant status in obese rats for 6 weeks. Subsequently, leptin and adiponectin levels and histopathological examination of adipose tissue were carried out. Results showed that IF with FCM or FCM-D decreased body weight by 0.92 and −5.45%, respectively. IF alone lowered non-fasting blood glucose (NFBG) and fasting blood glucose FBG after 6 weeks, whereas adding FCM or FCM-D reduced NFBG after 4 weeks. Intermittently fasting obese rats given FCM or FCM-D had the lowest blood glucose levels (BGL). The hypolipidemic effects of IF, FCM, and FCM-D on obese rats reduced triglycerides (TG), cholesterols (CHO), and their derivatives. FCM-D with IF presented a superior effect on lipid profile. A reduction rate of 40, 37, 66, and 40% for TG, CHO, low-density lipoprotein (LDL-c), and very low-density lipoprotein (VLDL-c), respectively, and an increase in HDL-C by 34% were noticed. Reductions of 40, 37, 66, and 40% for TG, CHO, LDL-c, and VLDL-c, respectively, and a 34% rise in high-density lipoprotein (HDL-C) were noted. Combining IF with FCM or FCM-D lowered the atherogenic index (AI) by 42% and 59%, respectively. Remarkably, treating rats with FCM+IF or FCM-D+IF effectively attenuated leptin and adiponectin levels. Malondialdehyde (MDA) was significantly decreased in a type-dependent manner. Implementing FCM-D or FCM with IF significantly attenuated reduced glutathione (GSH), superoxide dismutase (SOD), MDA, and catalase (CAT) levels. The most efficient treatment was giving FCM-D with IF. Histopathologically, adipocyte lipolysis increases free fatty acids (FFAs) and promotes inflammation. Only IF+FCM-D indicated no histopathological alteration except for a few focal areas of a few inflammatory cell infiltrations in the parenchyma. In conclusion, combining IF and Probiotic-FCM or Probiotic-FCM-D effectively accelerated weight loss, attenuated metabolic markers, and reversed histopathological alterations. Thus, IF combined with Probiotic-FCM or Probiotic-FCM-D is highly recommended for weight loss, strengthening antioxidative status, and preventing health disorders.

Gut microbiota and obesity

Worldwide, adults and childhood obesity are increasing alarmingly, being a major health problem. Obesity is correlated with an increased incidence of various systemic diseases including cancer, heart diseases, and diabetes mellitus type 2. Risk factors for obesity are dysbiosis, genetic, socioeconomic, behavioural and environmental. The gut microbiota has beneficial effects on human health, like host immune system stimulation, being influenced by pH, or nutrient intake. Studies performed on humans and animal models reported differences regarding microbiota at lean and obese individuals. The consumption of probiotics and prebiotics may balance the microbiota with positive effects in obesity. The main aim of this review is to reveal the interaction between dysbiosis and obesity

A Combined Supplement of Probiotic Strains AP-32, bv-77, and CP-9 Increased Akkermansia mucinphila and Reduced Non-Esterified Fatty Acids and Energy Metabolism in HFD-Induced Obese Rats

Obesity is referred to as a condition in which excess body fat has accumulated to an extent that it causes negative impacts on health. The formation of body fat is regulated by complicated networks in relation to energy metabolism, and gut microbiota have been regarded as a key player. Studies have shown that supplements of probiotics provide benefits to health, including an improvement in metabolic syndrome and the control of body weight. In the present study, three probiotic strains, AP-32, bv-77, and CP-9, stood out from nine candidates using a lipid consumption assay, and were subsequently introduced to further animal tests. A rodent model of obesity was induced by a high-fat diet (HFD) in Sprague-Dawley (SD) rats, and three probiotic strains were administered either separately or in a mixture. A low dose (5 × 10⁹ CFU/kg/day) and a high dose (2.5 × 10¹⁰ CFU/kg/day) of probiotics were orally provided to obese rats. The bioeffects of the probiotic supplements were evaluated based on five aspects: (1) the body weight and growth rate; (2) ketone bodies, non-esterified fatty acids (NEFAs), and feed efficiency; (3) blood biochemistry; (4) fat content; and (5) gut microbiota composition. Our results demonstrated that the supplement of AP-32, CP-9, and bv-77 alleviated the increasing rate of body weight and prevented the elevation of NEFAs and ketone bodies in obese rats. Although the effect on fat content showed a minor improvement, the supplement of probiotics displayed significant improvements in HFD-induced poor blood biochemical characteristics, such as alanine aminotransferase (ALT), aspartate Transaminase (AST), and uric acid, within 4 weeks. Furthermore, the combined supplement of three strains significantly increased Akkermansia mucinphila as compared with three individual strains, while its enrichment was negatively correlated with NEFAs and energy metabolism. In general, a mixture of three probiotic strains delivered a better outcome than a single strain, and the high dose of supplements provided a more profound benefit than the low dose. In conclusion, three probiotic strains, AP-32, bv-77, and CP-9, can alleviate body fat formation in obese rats. Furthermore, a combined supplement of these three probiotic strains may have potential in treating or controlling metabolic disorders.

GPR40 Agonist Ameliorate Pathological Neuroinflammation of Alzheimer's Disease via the Modulation of Gut Microbiota and Immune System, a Mini-Review

Alzheimer's disease (AD) is a central disease with high incidence, and its pathological process is closely associated with changes of some biological indicators in the periphery. Among them, the intestinal flora mainly causes a series of pathological changes such as inflammation through the immune system, which may contribute to the pathological process of AD. In this paper, we mainly focused the relationship between gut microbiota and immune system disorder in the neuropathology of AD, underlining the significance of the advanced mechanism of inflammatory response and providing a new direction for the treatment of AD.

Flavonoids from Rosa davurica Pall. fruits prevent high-fat diet-induced obesity and liver injury via modulation of the gut microbiota in mice

Rosa davurica Pall. (RDP) fruits are popularly consumed as beverages and healthy food in China because of their various beneficial activities. In particular, flavonoids are one of the major active ingredients of RDP fruits with predominant pharmacological effects. However, the anti-obesity activities of flavonoids from RDP fruits and their regulation effect on the gut microbiota have not been determined. In the present study, the flavonoid-rich extracts (RDPF) were isolated from RDP fruits and their anti-obesity effects were investigated using a high-fat diet (HFD)-induced obese mouse model. The results showed that RDPF intervention significantly inhibited the body weight, liver weight, kidney weight and epididymal adipose tissue weight of HFD-fed mice without affecting the calorie intake. Plasma lipid levels were also significantly lowered by RDPF treatment. Histological examination showed that RDPF supplementation partially recovered HFD-induced hepatic steatosis in the liver. RDPF also prevented oxidative injury of the liver, as evidenced by the altered superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) levels. The expression levels of CCAAT/enhancer binding protein α (C/EBPα), sterol regulatory element binding protein-1C (SREBP-1C), fatty acid synthase (FAS), acyl-coenzyme A oxidase 1 (ACOX1), peroxisome proliferator-activated receptor (PPARα) and CAT mRNA in the livers of mice were also regulated by RDPF administration. 16S rRNA gene sequence data further indicated that RDPF addition increased the microbial diversity and reshaped the community composition. Intriguingly, RDPF intervention did not exhibit inhibitory tendency toward the ratio of Firmicutes to Bacteroidetes, but markedly decreased the relative abundance of Erysipelotrichaceae. This study provided novel insights into the application of RDPF in the food industry.

Combination of Limosilactobacillus fermentum MG4231 and MG4244 attenuates lipid accumulation in high-fat diet-fed obese mice

We investigated the anti-obesity effect and the underlying mechanisms of action of human-derived Limosilactobacillus fermentum MG4231, MG4244, and their combination, in high-fat diet-induced obese mice. Administration of the Limosilactobacillus strains decreased body weight gain, liver and adipose tissue weight, and glucose tolerance. Serum levels of total cholesterol, low-density lipoprotein-cholesterol, and leptin were reduced, while adiponectin increased. The administration of Limosilactobacillus strains improved the histopathological features of liver tissue, such as hepatic atrophy and inflammatory penetration, and significantly reduced the content of triglyceride in the liver. Limosilactobacillus administration discovered a significant reduction in the size of the adipocytes in the epididymal tissue. Limosilactobacillus treatment significantly reduced the expression of important regulators in lipid metabolism, including peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein α, fatty acid synthase (FAS), adipocyte-protein 2, and lipoprotein lipase in the epididymal tissue. Also, Limosilactobacillus lowered sterol regulatory element-binding protein 1-c and FAS in the liver tissue. Such changes in the expression of these regulators in both liver and epididymis tissue were caused by Limosilactobacillus upregulating phosphorylation of AMP-activated protein kinase and acetyl-CoA carboxylase. Therefore, we suggest that the use of the combination of L. fermentum MG4231 and MG4244, as probiotics could effectively inhibit adipogenesis and lipogenesis from preventing obesity.

Chronic oral exposure to pesticides and their consequences on metabolic regulation: role of the microbiota

Pesticides have long been used in agriculture and household treatments. Pesticide residues can be found in biological samples for both the agriculture workers through direct exposure but also to the general population by indirect exposure. There is also evidence of pesticide contamination in utero and trans-generational impacts. Whilst acute exposure to pesticides has long been associated with endocrine perturbations, chronic exposure with low doses also increases the prevalence of metabolic disorders such as obesity or type 2 diabetes. Dysmetabolism is a low-grade inflammation disorder and as such the microbiota plays a role in its etiology. It is therefore important to fully understand the role of microbiota on the genesis of subsequent health effects. The digestive tract and mostly microbiota are the first organs of contact after oral exposure. The objective of this review is thus to better understand mechanisms that link pesticide exposure, dysmetabolism and microbiota. One of the key outcomes on the microbiota is the reduced Bacteroidetes and increased Firmicutes phyla, reflecting both pesticide exposure and risk factors of dysmetabolism. Other bacterial genders and metabolic activities are also involved. As for most pathologies impacting microbiota (including inflammatory disorders), the role of prebiotics can be suggested as a prevention strategy and some preliminary evidence reinforces this axis.

Effect of a Humanized Diet Profile on Colonization Efficiency and Gut Microbial Diversity in Human Flora-Associated Mice

Human flora-associated (HFA) mouse models allow us to design interventions for human disease research to test specific hypotheses and explore the complex commensal microbiome while avoiding the ethical limitations of using humans as models to directly study intestinal flora diseases. However, few studies have investigated the effect of a humanized diet profile (coarse-feed diet; CFD) on colonization efficiency and gut microbial diversity in HFA mice. We tested the colonization efficiency and gut microbial diversity in germ-free Kunming (KM) mice fed a CFD or a purified feed diet (PFD) at 1, 2, and 4 weeks. Although the colonization efficiencies differed significantly (67.50–70.00% vs. 72.69–85.96%) in the HFA mice, the colonization efficiency of the PFD-fed HFA mice (85.96%) was significantly higher than that of the CFD-fed mice (69.61%) at 2 weeks. At 4 weeks, the colonization efficiency of the PFD-fed mice (72.69%) was comparable to that of the CFD-fed mice (70.00%). Additionally, the gut microbial diversity of the CFD-fed HFA mice was similar to that of a human fecal donor. Regarding the Kyoto Encyclopedia of Genes and Genomes colonic microbiota metabolic pathways, the CFD-fed HFA mice showed more similarities to the human donor than to the PFD-fed mice in amino sugar and nucleotide sugar metabolism, biosynthesis of amino acids, carbon metabolism, purine metabolism, and phosphotransferase systems. In conclusion, the humanized diet profiles of the CFD and PFD could help establish human microbiotas in mice. Constructing HFA mouse models fed a CFD for 4 weeks may be useful in researching human-derived intestinal diseases.

Modulation of the Gut Microbiota and Liver Transcriptome by Red Yeast Rice and Monascus Pigment Fermented by Purple Monascus SHM1105 in Rats Fed with a High-Fat Diet

Hyperlipidemia can easily cause atherosclerosis and induce cardiovascular and cerebrovascular diseases. Red yeast rice (RYR) contains a variety of active ingredients and is commonly used as medicine and food, and has pharmacological effects such as lowering blood lipids. In this study, we select Monascus strain SHM1105 with a high yield of Monacolin K and monascus pigment (PIG), and studied the effects of the RYR and PIG fermented by this strain on blood lipids, intestinal flora, and liver transcriptome in hyperlipidemia model rats. The experimental results show that, compared with the high-fat model group, the weight growth rate, liver weight ratio, kidney weight ratio, spleen weight ratio, and fat weight ratio of rats in the gavage lovastatin (LOV), RYR, and PIG group were all significantly decreased (p < 0.05). Intervention with RYR and PIG can significantly reduce the serum TC, TG, and LDL-C levels, which has the effect of lowering blood lipids. The 16SrDNA sequencing results showed that the ratio of Firmicutes/Bacteroidetes decreased significantly (p ≤ 0.01) after the intervention of LOV, RYR, and PIG; the abundance of the ratio of Lachnospiraceae, Ruminococcaceae, Prevotellaceae, and Bacteroidales-S24-7-group also changed. The combined analysis of transcriptome and metabolome showed that lovastatin, RYR, and PIG can all improve lipid metabolism in rats by regulating Steroid hormone biosynthesis, Glycerolipid metabolism, and the Arachidonic acid metabolism pathway. In addition, RYR and PIG also have a unique way of regulating blood lipids. Although a lot of research on the lipid-lowering components of Monascus rice and the single pigment component of Monascus has been carried out, the actual application is RYR and pigments as mixtures, as a mixture of RYR and PIG contains a variety of biologically active ingredients, and each component may have a synergistic effect. Hence it has a lipid-lowering mechanism that lovastatin does not have. Therefore, RYR and PIG are effective in reducing lipid potential development and can be utilized in functional foods.

In Silico Comparison Shows that the Pan-Genome of a Dairy-Related Bacterial Culture Collection Covers Most Reactions Annotated to Human Microbiomes

The diversity of the human microbiome is positively associated with human health. However, this diversity is endangered by Westernized dietary patterns that are characterized by a decreased nutrient variety. Diversity might potentially be improved by promoting dietary patterns rich in microbial strains. Various collections of bacterial cultures resulting from a century of dairy research are readily available worldwide, and could be exploited to contribute towards this end. We have conducted a functional in silico analysis of the metagenome of 24 strains, each representing one of the species in a bacterial culture collection composed of 626 sequenced strains, and compared the pathways potentially covered by this metagenome to the intestinal metagenome of four healthy, although overweight, humans. Remarkably, the pan-genome of the 24 strains covers 89% of the human gut microbiome’s annotated enzymatic reactions. Furthermore, the dairy microbial collection covers biological pathways, such as methylglyoxal degradation, sulfate reduction, γ-aminobutyric (GABA) acid degradation and salicylate degradation, which are differently covered among the four subjects and are involved in a range of cardiometabolic, intestinal, and neurological disorders. We conclude that microbial culture collections derived from dairy research have the genomic potential to complement and restore functional redundancy in human microbiomes.

Obesogenic Effect of Sulfamethoxazole on Drosophila melanogaster with Simultaneous Disturbances on Eclosion Rhythm, Glucolipid Metabolism, and Microbiota

Antibiotics have recently gained attention because they are emerging environmental pollutants with obesogenic properties. In this study, Drosophila melanogaster were exposed to sulfamethoxazole (SMX), a sulfonamide antibiotic, and the effects were measured on circadian rhythm (represented by the eclosion rhythm), lipid metabolism, and microbiota. Circadian rhythm disorder was considered due to its connection with lipid metabolism and microbiota in association with obesity. SMX decreased the proportion of adult flies that eclosed in the morning (AM adults) and increased the proportion of PM adults. Moreover, SMX increased the body weight of PM adults, indicating that SMX exposure caused dysrhythmia in eclosion together with obesity. In measurements of key metabolites and metabolic enzymes, SMX exposure stimulated 3 indices in AM adults and 10 indices in PM adults. In AMP-activated protein kinase and insulin/IGF-1 signaling pathways, SMX upregulated six genes in AM adults and nine genes in PM adults. Finally, microbiota analysis demonstrated that SMX increased the Firmicutes/Bacteroides ratios (F/B) by 79.6- and 5.8-fold compared to concurrent controls in AM and PM adults. Collectively, these results suggest that SMX showed obesogenic effects accompanied with dysrhythmia and disturbances in lipid metabolism and microbiota. Further studies on the intrinsic connection are needed.

Effect of okra fruit powder supplementation on metabolic syndrome and gut microbiota diversity in high fat diet-induced obese mice

This study aimed to explore a novel strategy for dietary okra fruit powder (OFP) consumption on attenuation of non-alcohol fatty liver damage, lipid metabolic disorder and gut microbiota dysbiosis and associated mechanisms in high-fat diet (HFD)-induced obese mice. C57BL/6J mice were fed a normal diet and HFD feeds supplemented with or without OFP (2.5%, 5% and 10%, n = 10) for 12 weeks. The results showed that supplementation of OFP caused strong inhibition on HFD-caused high blood glucose, body weight gain and liver fat accumulation, as well as dyslipidemia involved in a dose-dependent modulation of hepatic FAS and CD36 expressions of obese mice. The hepatic LXR-α energy metabolism and PPAR-α pathway were also doubly activated by OFP to alleviate lipogenesis, obesity and metabolic syndrome. Malonaldehyde production was effectively antagonized, and glutathione peroxidase and superoxide dismutase activities were elevated by OFP supplementation in HFD-fed mice. OFP also significantly improved colonic SCFAs (acetic acid, propionic acid and butyrate acid) formation, especially for butyrate production via increasing the proportion of selected butyrate-producing bacteria. OFP also dramatically modified the gut microbial species at the family level with suppressing an increase in Proteobacteria, Actinobacteria and F/B ratio, and the decrease in Bacteroidetes caused by HFD. These findings support that dietary OFP consumption is a novel strategy to prevent obesity, metabolic syndrome and gut microbiota imbalance.

Genome-wide association study of morbid obesity in Han Chinese

BACKGROUND

As obesity is becoming pandemic, morbid obesity (MO), an extreme type of obesity, is an emerging issue worldwide. It is imperative to understand the factors responsible for huge weight gain in certain populations in the modern society. Very few genome-wide association studies (GWAS) have been conducted on MO patients. This study is the first MO-GWAS study in the Han-Chinese population in Asia.

METHODS

We conducted a two-stage GWAS with 1110 MO bariatric patients (body mass index [BMI] ≥ 35 kg/m2) from Min-Sheng General Hospital, Taiwan. The first stage involved 575 patients, and 1729 sex- and age-matched controls from the Taiwan Han Chinese Cell and Genome Bank. In the second stage, another 535 patients from the same hospital were genotyped for 52 single nucleotide polymorphisms (SNPs) discovered in the first stage, and 9145 matched controls from Taiwan Biobank were matched for confirmation analysis.

RESULTS

The results of the joint analysis for the second stage revealed six top ranking SNPs, including rs8050136 (p-value = 7.80 × 10- 10), rs9939609 (p-value = 1.32 × 10- 9), rs1421085 (p-value = 1.54 × 10- 8), rs9941349 (p-value = 9.05 × 10- 8), rs1121980 (p-value = 7.27 × 10- 7), and rs9937354 (p-value = 6.65 × 10- 7), which were all located in FTO gene. Significant associations were also observed between MO and RBFOX1, RP11-638 L3.1, TMTC1, CBLN4, CSMD3, and ERBB4, respectively, using the Bonferroni correction criteria for 52 SNPs (p < 9.6 × 10- 4).

CONCLUSION

The most significantly associated locus of MO in the Han-Chinese population was the well-known FTO gene. These SNPs located in intron 1, may include the leptin receptor modulator. Other significant loci, showing weak associations with MO, also suggested the potential mechanism underlying the disorders with eating behaviors or brain/neural development.

Tibet kefir milk decreases fat deposition by regulating the gut microbiota and gene expression of Lpl and Angptl4 in high fat diet-fed rats

The role of Tibet kefir milk (TKM) feeding on fat deposition was investigated in high-fat diet (HFD)-fed human flora-associated (HFA) rats. TKM feeding reduced abdominal fat mass from 33.9 g to 24.0 g and serum triglyceride (TG) from 0.75 mmol/L to 0.47 mmol/L, and caused lipoprotein lipase (LPL) to decrease from 395.8 ± 36.0 ng/L to 362.3 ± 64.4 ng/L in fat and increase from 287.3 ± 40.8 ng/L to 329.8 ± 48.5 ng/L and 312.5 ± 22.0 to 375.1 ± 30.8 ng/L in liver and serum, respectively. Likewise, TMK feeding down-regulated Lpl gene expression in fat and Angptl4 (angiopoietin-like protein-4, also known as fasting-induced adipose factor) gene expression in liver, and up-regulated Angptl4 gene expression in fat. Sequence analysis showed that the Firmicutes/Bacteroidetes proportion and Verrucomicrobia at the phylum level, Akkermansia, Escherichia and Oscillospira at the genus level, as well as Escherichia coli at the species level were positively regulated by TKM. The results indicated that TKM decreased abdominal fat deposition and serum TG by regulating Lpl and Angptl4 at the transcriptional level. The microbiota groups mentioned above were regulated by TKM at the same time and may be the potential intervention targets to reduce fat deposition.

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.

Intestinal Sensing by Gut Microbiota: Targeting Gut Peptides

There are more than 2 billion overweight and obese individuals worldwide, surpassing for the first time, the number of people affected by undernutrition. Obesity and its comorbidities inflict a heavy burden on the global economies and have become a serious threat to individuals' wellbeing with no immediate cure available. The causes of obesity are manifold, involving several factors including physiological, metabolic, neural, psychosocial, economic, genetics and the environment, among others. Recent advances in genome sequencing and metagenomic profiling have added another dimension to this complexity by implicating the gut microbiota as an important player in energy regulation and the development of obesity. As such, accumulating evidence demonstrate the impact of the gut microbiota on body weight, adiposity, glucose, lipid metabolism, and metabolic syndrome. This also includes the role of microbiota as a modulatory signal either directly or through its bioactive metabolites on intestinal lumen by releasing chemosensing factors known to have a major role in controlling food intake and regulating body weight. The importance of gut signaling by microbiota signaling is further highlighted by the presence of taste and nutrient receptors on the intestinal epithelium activated by the microbial degradation products as well as their role in release of peptides hormones controlling appetite and energy homeostasis. This review present evidence on how gut microbiota interacts with intestinal chemosensing and modulates the release and activity of gut peptides, particularly GLP-1 and PYY.

Polygonatum odoratum Polysaccharides Modulate Gut Microbiota and Mitigate Experimentally Induced Obesity in Rats

Increasing evidence suggests that the gut microbiota plays vital roles in metabolic diseases. Polygonatum odoratum extract alleviates hyperglycemia and hyperlipidemia, but the underlying mechanism remains unclear. This study investigated the effects of P. odoratum polysaccharides (POPs) on high-fat diet (HFD)-induced obesity in rats and whether these effects were related to modulation of gut microbiota. POP treatment attenuated weight gain, fat accumulation, epididymal adipocyte size, liver triglycerides, and total liver cholesterol content in HFD-fed rats. POP administration also increased short-chain fatty acids (SCFAs), including isobutyric acid, butyric acid, and valeric acid. POP upregulated the expression of genes involved in adipocyte differentiation (Pparg, Cebpa, Cebpb) and lipolysis (Ppara, Atgl), and downregulated those related to lipid synthesis (Srebpf1, Fabp4, Fas), with corresponding changes in PPARγ and FABP4 protein expression. Finally, POP enhanced species richness and improved the gut microbiota community structure, reducing the relative abundances of Clostridium, Enterococcus, Coprobacillus, Lactococcus, and Sutterella. Principal coordinates analysis (PCoA) revealed a clear separation between HFD-fed rats and all other treatment groups. Correlation analysis identified negative and positive associations between obesity phenotypes and 28 POP-influenced operational taxonomic units (OTUs), including putative SCFA-producing bacteria. Our data suggest that POP supplementation may attenuate features of obesity in HFD-fed rats in association with the modulation of gut microbiota.