Gut bacteria Akkermansia is associated with reduced risk of obesity: evidence from the American Gut Project

Early life gut microbiome and its impact on childhood health and chronic conditions

The development of the gut microbiome is crucial to human health, particularly during the first three years of life. Given its role in immune development, disturbances in the establishment process of the gut microbiome may have long term consequences. This review summarizes evidence for these claims, highlighting compositional changes of the gut microbiome during this critical period of life as well as factors that affect gut microbiome development. Based on human and animal data, we conclude that the early-life microbiome is a determinant of long-term health, impacting physiological, metabolic, and immune processes. The early-life gut microbiome field faces challenges. Some of these challenges are technical, such as lack of standardized stool collection protocols, inconsistent DNA extraction methods, and outdated sequencing technologies. Other challenges are methodological: small sample sizes, lack of longitudinal studies, and poor control of confounding variables. To address these limitations, we advocate for more robust research methodologies to better understand the microbiome's role in health and disease. Improved methods will lead to more reliable microbiome studies and a deeper understanding of its impact on health outcomes.

Complex relationship between childhood obesity and the gut microbiota

Recently, the gut microbiota has been identified as a significant risk factor associated with metabolic disorders related to obesity. Advances in high-throughput sequencing technology have clarified the relationship between childhood obesity and changes in the gut microbiota. This commentary focuses on analyzing the study by Li et al, which utilized 16S rRNA molecular markers to compare differences in gut microbiota between obese and normal-weight children. Additionally, the review by Pan et al is referenced to supplement perspectives and evaluate the findings of this study. We also analyze the strengths and limitations of the original study and suggest potential research directions to elucidate the complex relationship between gut microbiota and childhood obesity, thereby providing a scientific basis for developing effective prevention and treatment strategies.

Reutericyclin mitigates risperidone-induced suppression of anaerobic energy expenditure

Recent studies from our laboratory demonstrated that the gut microbial community represents a thermogenic biomass, as cecectomy causes an ∼8% decrease in total energy expenditure (EE) via suppression of anaerobic EE. The composition of the microbial community also dictates the EE of the microbial biomass as treatment with the antipsychotic, risperidone, suppresses anaerobic EE in a microbiome-dependent manner. Finally, we have determined that a specialized metabolite produced by Limosilactobacillus reuteri, reutericyclin (RTC), opposes the weight-gain effects of risperidone. In the present study, we performed comprehensive evaluations of energy balance in female C57BL/6J mice treated with risperidone, RTC, or both, to identify mechanisms by which RTC affects energy balance to mitigate risperidone-induced weight gain. We observed that risperidone suppressed anaerobic EE, and that RTC coadministration ameliorated the anaerobic EE suppression and weight gain induced by risperidone. Because anaerobic EE is dependent on the gut microbiota, we performed 16S and whole genome shotgun sequencing on stool and cecal samples following whole animal calorimetry. Risperidone and RTC treatments reciprocally modified the relative abundance of taxa known to participate in fermentation, especially for the production of short-chain fatty acids, which have been correlated with health and leanness in both humans and mice. Together, our data demonstrate that treatment with RTC positively modulates anaerobic EE, possibly by enhancing fermentation of the gut microbial community, and may represent a novel therapeutic in the treatment of obesity.NEW & NOTEWORTHY The gut microbial community represents a thermogenic biomass. The composition of the microbial community dictates energy expenditure of the microbial biomass and is altered by xenobiotics and bacterial metabolites. This study demonstrates that treatment with reutericyclin positively modulates anaerobic energy expenditure and may represent a novel therapeutic in the treatment of obesity.

Assessment of gut microbiota in the elderly with sarcopenic obesity: a case-control study

Objectives

Sarcopenic obesity is a multifactorial disorder commonly found in elderly individuals. One contributing factor is gut microbiota dysbiosis. This study compared the abundance of certain bacteria in elderly individuals with obesity and sarcopenic obesity.

Methods

The study included 50 elderly individuals over 65 with a body mass index (BMI) of over 30 kg/m², both sexes. Participants were divided into two groups, each with 25 individuals, based on the diagnosis of sarcopenia using the EWGSOP2 criteria. Individuals with underlying diseases, those using antibiotics, and those with a history of gastrointestinal surgery were excluded. Stool samples were stored at -80 °C, and DNA was extracted using standard kits. Bacterial DNA sample quality was assessed using a Nanodrop device. Bacterial frequency was measured using qPCR. The log cfu for each bacteria was calculated and compared in both groups using an independent t-test. Spearman measured the correlation between bacterial genera and physical performance in SPSS 26.

Results

The case group had a significantly higher average age (70.96) than the control group (68.32). The average BMI was the same in both groups. The frequency of Escherichia (p-value = 0.046) and Bifidobacterium (p-value = 0.017) was significantly higher in the case group. There was no significant difference in the frequency of Lactobacillus and Akkermansia.

Conclusion

The study uncovered substantial differences in gut microbiota composition between elderly individuals experiencing sarcopenic obesity and those with obesity alone. The findings suggest that dysbiosis, characterized by an excessive presence of Bifidobacterium, Escherichia, and Akkermansia, may be associated with sarcopenic obesity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-025-01584-x.

Omega-3 and conjugated fatty acids impact on human microbiota modulation using an in vitro fecal fermentation model

BACKGROUND & AIMS

Gut microbiota has been gaining increasing attention and its important role in the maintenance of a general good health condition is already established. The potential of gut microbiota modulation through diet is an important research focus to be considered. Lipids, as omega-3 fatty acids, are well known for their beneficial role on organs and corresponding diseases. However, their impact on gut microbiota is still poorly defined, and studies on the role of other polyunsaturated fatty acids, such as conjugated linoleic and linolenic acids, are even scarcer.

METHODS

By using an in vitro human fermentation model, we assessed the effect of omega-3, CLA isomers, and punicic acid on microbiota modulation.

RESULTS

Fish oil, Omega-3, and CLA samples positively impact Akkermansia spp. and Bifidobacterium spp. growth. Moreover, all the samples supported Roseburia spp. growth after 24 h of fermentation and, importantly, they were able to maintain the Firmicutes: Bacteroidetes ratio near 1. All the bioactive fatty acid samples, except Pomegranate oil, were able to significantly increase butyrate levels compared to those found in the positive control (FOS) sample. Moreover, Fish oil and Omega-3 samples were able to increase the concentration of GABA, alanine, tyrosine, phenylalanine, isoleucine, and leucine between 12 and 24 h of fermentation.

CONCLUSIONS

The impact of the assessed polyunsaturated fatty acids in gut microbiota has been observed in its impact on key bacteria (Akkermansia, Bifidobacterium, and Roseburia) as well as their metabolic byproducts, including butyrate and amino acids, which could potentially play a role in modulating the gut-brain axis.

Harnessing Probiotics: Exploring the Role of the Gut Microbiome in Combating Obesity

Obesity has become a global health crisis driven by genetic, environmental, and lifestyle factors, often linked to gut microbiome imbalances. Probiotics, particularly Lactobacillus and Bifidobacterium strains, have shown promise in clinical trials by promoting weight loss, improving lipid profiles, and addressing gut dysbiosis associated with obesity. This review surveys the literature on the microbiome and obesity, emphasizing the clinical relevance of probiotics in treatment strategies. Our comprehensive PubMed search highlights the mechanisms through which probiotics influence metabolic health, including their effects on inflammation and appetite regulation. We also explore promising future research directions and the potential for integrating probiotics into clinical practice. While results are encouraging, the evidence is limited by strain variability, small sample sizes, short trial durations, and individual differences in microbiota composition. More extensive, long-term studies with standardized methods are crucial to confirm the effectiveness of probiotics as viable anti-obesity treatments.

Grape polyphenols reduce fasting glucose and increase hyocholic acid in healthy humans: a meta-omics study

Grape polyphenols (GPs) are rich in B-type proanthocyanidins, which promote metabolic resilience. Longitudinal metabolomic, metagenomic, and metaproteomic changes were measured in 27 healthy subjects supplemented with soy protein isolate (SPI, 40 g per day) for 5 days followed by GPs complexed to SPI (GP-SPI standardized to 5% GPs, 40 g per day) for 10 days. Fecal, urine, and/or fasting blood samples were collected before supplementation (day -5), after 5 days of SPI (day 0), and after 2, 4 and 10 days of GP-SPI. Most multi-omic changes observed after 2 and/or 4 days of GP-SPI intake were temporary, returning to pre-supplementation profiles by day 10. Shotgun metagenomics sequencing provided insights that could not be captured with 16S rRNA amplicon sequencing. Notably, 10 days of GP-SPI decreased fasting blood glucose and increased serum hyocholic acid (HCA), a glucoregulatory bile acid, which negatively correlated with one gut bacterial guild. In conclusion, GP-induced suppression of a bacterial guild may lead to higher HCA and lower fasting blood glucose.

The lotus seed starch-EGCG complex modulates obesity in C57BL/6J mice through the regulation of the gut microbiota

The starch-polyphenol complex, identified as RS5-resistant starch, has been shown to regulate the gut environment and inhibit metabolic diseases, including obesity. In a study with C57BL/6 obese mice fed LSE, potential anti-obesity effects were demonstrated through physiological and biochemical assessments, gut microbiota analysis, and mechanistic insights. The study showed that LSE reduced mice body weight, serum total cholesterol, and triglycerides (P < 0.05). Serum inflammatory markers (TNF-α, IL-6, IL-1β) and LPS levels were significantly decreased, while glucose tolerance (AUC reduced by 29.29 %) and insulin sensitivity (AUC reduced by 31.79 %) were improved. Histological analysis indicated reduction in adipocyte size and attenuation of hepatic steatosis. Gut microbiota profiling demonstrated LSE increased beneficial bacteria genera Faecalibacterium, Bifidobacterium, and Akkermansia. This correlated with enhanced SCFA production (acetate 41.53 %, propionate 45.52 %, butyrate 57.49 % increase). These findings demonstrate that LSE exerts anti-obesity effects through modulation of the gut microbiota-SCFA-metabolic axis, supporting starch-polyphenol complexes as functional food candidates.

Unveiling the Antiobesity Mechanism of Sweet Potato Extract by Microbiome, Transcriptome, and Metabolome Analyses in Mice

This study aimed to elucidate the antiobesity mechanisms of sweet potato extract (SPE) through biochemical, gut microbiome, liver transcriptome, and metabolome analyses. Administration of SPE to high-fat-diet-fed mice significantly reduced body weight gain, serum low-density lipoprotein cholesterol, hepatic lipid accumulation, and adipocyte hypertrophy, which were closely linked to gut microbiome composition. SPE notably increased the abundance of Eubacterium_coprostanoligenes_group_unclassified and decreased that of Kineothrix, both of which were strongly associated with short-chain fatty acid (SCFA) production. LC-QTOF-MS analysis identified resin glycoside compounds from SPE with reduced levels in mouse feces, suggesting their utilization in vivo. SPE also promoted dietary fat excretion. Liver transcriptomic and metabolomic profiling revealed that SPE may exert antiobesity effects by modulating the bile-sphingolipid metabolism, which was closely correlated with the reshaped gut microbiomes and SCFAs. These findings provide new insights into the antiobesity effects and mechanisms of SPE.

Intestinal flora was associated with occurrence risk of chronic non-communicable diseases

BACKGROUND

The intestinal flora (IF) has been linked to risks of non-communicable diseases, especially various cancers, stroke, and Alzheimer's disease. However, many uncertainties of these associations during different stages of growth, development, and aging still exist. Therefore, further in-depth explorations are warranted.

AIM

To explore the associations of the human IF with disease risks during different stages of growth, development, and aging to achieve more accurate and convincing conclusions.

METHODS

Cohort, cross-sectional, case-control, and Mendelian randomization studies published in the PubMed and Web of Science databases until December 31, 2023 were systematically reviewed to clarify the associations of the IF at the genus level with the risks of various non-communicable diseases, which were grouped in accordance with the 10th revision of the International Classification of Diseases.

RESULTS

In total, 57 studies were included to quantitatively examine the influence of the IF on the risks of 30 non-communicable diseases during different stages of growth, development, and aging. Population studies and Mendelian randomization studies confirmed positive associations of the abundances of Bifidobacterium and Ruminococcus with multiple sclerosis.

CONCLUSION

These findings contribute to a deeper understanding of the roles of the IF and provide novel evidence for effective strategies for the prevention and treatment of non-communicable diseases. In the future, it will be necessary to explore a greater variety of research techniques to uncover the specific mechanisms by which gut microbiota trigger diseases and conduct in-depth studies on the temporal relationship between microbiota alterations and diseases, so as to clarify the causal relationship more accurately.

Akkermansia muciniphila and Its Extracellular Vesicles Affect Endocannabinoid System in in vitro Model

INTRODUCTION

Recent studies indicate that the gut microbiota controls the host's immune system. Probiotics use different signaling pathways to regulate intestinal permeability, barrier integrity, and energy balance.

METHODS

This research examined how Akkermansia muciniphila and its extracellular vesicles (EVs) impact inflammation and genes related to the endocannabinoid system in the STC-1 cell line through RT-PCR and ELISA assays.

RESULTS

The study's results indicated that EVs had a significant impact on GLP-1 expression compared to the multiplicity of infections (MOI) ratio. Notably, there was a substantial increase in the expression of PYY and GLP-1 genes across all treatments (p < 0.05). Conversely, the expression of CB-1, CB-2, and FAAH genes notably decreased in the STC-1 cell line when treated with MOI 50 of A. muciniphila and an EV concentration of 100 μg/mL (p < 0.05). Both MOI 50 of A. muciniphila and an EV concentration of 100 μg/mL significantly enhanced the expression of the TLR-2 gene. In contrast, EVs at a concentration of 100 μg/mL substantially reduced TLR-4 gene expression. A. muciniphila-derived EVs notably decreased the levels of inflammatory cytokines (TNF-α and IL-6), while increasing IL-10 expression at MOI 100 and an EV concentration of 100 μg/mL. These findings suggest that A. muciniphila and its EVs could regulate the expression of specific genes, serving as targets for maintaining host energy balance.

CONCLUSIONS

In summary, this study illustrates that A. muciniphila-derived EVs exhibit anti-inflammatory properties and have the potential to modulate gene expression in cases of obesity and gastrointestinal tract inflammation.

Akkermansia muciniphila Modulates Central Nervous System Autoimmune Response and Cognitive Impairment by Inhibiting Hippocampal NLRP3-Mediated Neuroinflammation

BACKGROUND

Numerous studies have demonstrated the significant role of Akkermansia muciniphila (A. muciniphila) in enhancing host immune responses and metabolic functions. However, its increased presence in multiple sclerosis (MS) patients has led to a focus on the relationships between A. muciniphila and diseases, with the underlying mechanisms remaining unknown.

METHOD

Solochrome cyanin, hematoxylin-eosin staining (H&E) and immunofluorescence staining were used to assess demyelination and inflammation. Gut microbiota changes were examined by 16S rRNA sequencing. Intracellular cytokine levels were assessed by flow cytometry. Cognitive impairment was evaluated using four behavioral tests. Intestinal barrier function and pyrin domain-containing protein 3 (NLRP3)-mediated neuroinflammation were evaluated by immunoblotting.

RESULTS

We found that treatment with an appropriate dose of A. muciniphila (5.0 × 107 CFU/mL) reduced neuropathology and disease severity in experimental autoimmune encephalomyelitis (EAE) mice. In addition, A. muciniphila supplementation increased the diversity and abundance of intestinal microbiota while decreasing the Firmicutes/Bacteroidetes ratio. Moreover, it improved intestinal barrier function and attenuated Th17 responses in the gut, central nervous system (CNS), and lymphoid tissues, without affecting Treg response in the lymphoid tissue. Furthermore, A. muciniphila administration partly regulated cognitive impairment and hippocampal NLRP3-mediated neuroinflammation.

CONCLUSION

Our results suggest that A. muciniphila holds promise as a probiotic for treating NLRP3-associated inflammatory disorders and cognitive impairment, including MS.

Obesity and the gut microbiota: implications of neuroendocrine and immune signaling

Obesity is a major health challenge due to its high prevalence and associated comorbidities. The excessive intake of a diet rich in fat and sugars leads to a persistent imbalance between energy intake and energy expenditure, which increases adiposity. Here, we provide an update on relevant diet-microbe-host interactions contributing to or protecting from obesity. In particular, we focus on how unhealthy diets shape the gut microbiota and thus impact crucial intestinal neuroendocrine and immune system functions. We describe how these interactions promote dysfunction in gut-to-brain neuroendocrine pathways involved in food intake control and postprandial metabolism and elevate the intestinal proinflammatory tone, promoting obesity and metabolic complications. In addition, we provide examples of how this knowledge may inspire microbiome-based interventions, such as fecal microbiota transplants, probiotics, and biotherapeutics, to effectively combat obesity-related disorders. We also discuss the current limitations and gaps in knowledge of gut microbiota research in obesity.

Integrated microbiome and metabolomics analysis reveals the alleviating effect of Pediococcus acidilactici on colitis

Colitis is a complicated disease caused by multiple factors, seriously threatening the host health and the development of animal husbandry. Probiotics have been demonstrate to participate in the active regulation of multiple gastrointestinal disease, gut microbiota and metabolism, but research on the efficacy of Pediococcus acidilactici isolated from dogs in alleviating colitis remains scarce. Here, we aimed to investigate the ameliorative effects of Pediococcus acidilactici isolated from dogs on colitis induced by LPS and its underlying molecular mechanisms. For this purpose, we collected colon contents from 15 mice for amplicon sequencing and metabolic analysis. Results showed that Pediococcus acidilactici could relieve the colon damage and cytokine disorder caused by colitis. Microbiome analysis showed that colitis could cause a significant decrease in the gut microbial diversity and abundance, but Pediococcus acidilactici administration could restore the microbial index to the control level. Metabolomics analysis showed that 8 metabolic pathways and 5 (spermine, L-Arginine, 15-Deoxy-Delta12,14-PGJ2, prostaglandin J2, and 15(S)-HETE) metabolites may be involved in the alleviation of colitis by Pediococcus acidilactici. In summary, these findings demonstrated that the positive regulation effect of Pediococcus acidilactici on gut microbiota and metabolism may be one of its underlying mechanisms to alleviate colitis. Additionally, this study also conveyed a vital message that Pediococcus acidilactici isolated from dogs may serve as a promising candidate to ameliorate Pediococcus acidilactici.

Moderate Highland Barley Intake Affects Anti-Fatigue Capacity in Mice via Metabolism, Anti-Oxidative Effects and Gut Microbiota

OBJECTIVES

this study aimed to explore the effects of different intake levels (20-80%) of highland barley on the anti-fatigue capacity of ICR mice, focusing on energy metabolism, metabolite accumulation, oxidative stress, and changes in the gut microbiota.

METHODS

male ICR mice were assigned to five groups: control (normal diet) and four experimental groups with highland barley supplementation at 20%, 40%, 60%, and 80% of total dietary energy. Anti-fatigue performance was assessed by behavioral experiments (rotarod, running, and exhaustive swimming tests), biochemical markers, and gut microbiota analysis.

RESULTS

the results showed that moderate supplementation (20%) significantly enhanced exercise endurance and anti-fatigue capacity, as evidenced by increased liver glycogen (134.48%), muscle glycogen (87.75%), ATP content (92.07%), Na+-K+-ATPase activity (48.39%), and antioxidant enzyme activities (superoxide dismutase (103.31%), catalase (87.75%), glutathione peroxidase (81.14%). Post-exercise accumulation of blood lactate, quadriceps muscle lactate, serum urea nitrogen, and the oxidative stress marker malondialdehyde was significantly reduced, with differences of 31.52%, 21.83%, 21.72%, and 33.76%, respectively. Additionally, 20% supplementation promoted the growth of beneficial gut microbiota associated with anti-fatigue effects, including unclassified_f_Lachnospiraceae, g_norank_f_Peptococcaceae, Lachnospiraceae NK4A136, Colidextribacter, and Turicibacter. However, when intake reached 60% or more, anti-fatigue effects diminished, with decreased antioxidant enzyme activity, increased accumulation of metabolic waste, and a rise in potentially harmful microbiota (Allobaculum, Desulfovibrio, and norank_f_norank_o_RF39).

CONCLUSIONS

moderate highland barley supplementation (20% of total dietary energy) enhances anti-fatigue capacity, while excessive intake (≥60%) may have adverse effects.

A high fat, high sugar diet exacerbates persistent post-surgical pain and modifies the brain-microbiota-gut axis in adolescent rats

Persistent post-surgical pain (PPSP) occurs in a proportion of patients following surgical interventions. Research suggests that specific microbiome components are important for brain development and function, with recent studies demonstrating that chronic pain results in changes to the microbiome. Consumption of a high fat, high sugar (HFHS) diet can drastically alter composition of the microbiome and is a modifiable risk factor for many neuroinflammatory conditions. Therefore, we investigated how daily consumption of a HFHS diet modified the development of PPSP, brain structure and function, and the microbiome. In addition, we identified significant correlations between the microbiome and brain in animals with PPSP. Male and female rats were maintained on a control or HFHS diet. Animals were further allocated to a sham or surgery on postnatal day (p) p35. The von Frey task measured mechanical nociceptive sensitivity at a chronic timepoint (p65-67). Between p68-72 rats underwent in-vivo MRI to examine brain volume and diffusivity. At p73 fecal samples were used for downstream 16 s rRNA sequencing. Spearman correlation analyses were performed between individual microbial abundance and MRI diffusivity to determine if specific bacterial species were associated with PPSP-induced brain changes. We found that consumption of a HFHS diet exacerbated PPSP in adolescents. The HFHS diet reduced overall brain volume and increased white and grey matter density. The HFHS diet interacted with the surgical intervention to modify diffusivity in numerous brain regions which were associated with specific changes to the microbiome. These findings demonstrate that premorbid characteristics can influence the development of PPSP and advance our understanding of the contribution that the microbiome has on function of the brain-microbiota-gut axis.

Malnutrition and Its Influence on Gut sIgA-Microbiota Dynamics

In the current era, malnutrition is seen as both undernutrition and overweight and obesity; both conditions are caused by nutrient deficiency or excess and improper use or imbalance in the intake of macro and micronutrients. Recent evidence suggests that malnutrition alters the intestinal microbiota, known as dysbiosis. Secretory immunoglobulin A (sIgA) plays an important role in maintaining and increasing beneficial intestinal microbiota populations and protecting against pathogenic species. Depletion of beneficial bacterial populations throughout life is also conditioned by malnutrition. This review aims to synthesize the evidence that establishes an interrelationship between diet, malnutrition, changes in the intestinal flora, and sIgA levels. Targeted nutritional therapies combined with prebiotic, probiotic, and postbiotic administration can restore the immune response in the intestine and the host's homeostasis.

Obesogenic cafeteria diet induces dynamic changes in gut microbiota, reduces myenteric neuron excitability, and impairs gut contraction in mice

The cafeteria diet (CAF) is a superior diet model in animal experiments compared with the conventional high-fat diet (HFD), effectively inducing obesity, metabolic disturbances, and multi-organ damage. Nevertheless, its impact on gut microbiota composition during the progression of obesity, along with its repercussions on the enteric nervous system (ENS) and gastrointestinal motility has not been completely elucidated. To gain more insight into the effects of CAF diet in the gut, C57BL/6 mice were fed with CAF or a standard diet for 2 or 8 wk. CAF-fed mice experienced weight gain, disturbed glucose metabolism, dysregulated expression of colonic IL-6, IL-22, TNFα, and TPH1, and altered colon morphology, starting at week 2. Fecal DNA was isolated and gut microbiota composition was monitored by sequencing the V3-V4 16S rRNA region. Sequence analysis revealed that Clostridia and Proteobacteria were specific biomarkers associated with CAF-feeding at week 2, while Bacteroides and Actinobacteria were prominent at week 8. In addition, the impact of CAF diet on ENS was investigated (week 8), where HuC/D+ neurons were measured and counted, and their biophysical properties were evaluated by patch clamp. Gut contractility was tested in whole-mount preparations. Myenteric neurons in CAF-fed mice exhibited reduced body size, incremented cell density, and decreased excitability. The amplitude and frequency of the rhythmic spontaneous contractions in the colon and ileum were affected by the CAF diet. Our findings demonstrate, for the first time, that CAF diet gradually changes the gut microbiota and promotes low-grade inflammation, impacting the functional properties of myenteric neurons and gut contractility in mice.NEW & NOTEWORTHY The gut microbiota changes gradually following the consumption of CAF diet. An increase in Clostridia and Proteobacteria is a hallmark of dysbiosis at the early onset of gut inflammation and obesity. The CAF diet was effective in inducing intestinal low-grade inflammation and alterations in myenteric neuronal excitability in mice. CAF diet is a reliable strategy to study the interplay between gut dysbiosis and low-grade inflammation, in addition to the mechanisms underlying gastrointestinal dysmotility associated with obesity.

Microbiota modifications in prehabilitation - the next step towards comprehensive preparation for surgery. The scoping review

This scoping review highlights the role of microbiota modifications in prehabilitation for surgical patients. It emphasises the importance of optimising gut microbiota through probiotics, synbiotics, and postbiotics to reduce surgical complications, such as surgical site infections (SSIs). The review highlights that gut dysbiosis, worsened by surgery, stress, antibiotics, and poor diet, can lead to increased infection risk and slower recovery. Evidence from systematic reviews, meta-analyses, and randomised controlled trials suggests that microbiota-targeted interventions can reduce SSIs, enhance immune responses, and promote quicker recovery. The review advocates for an individualised approach to prehabilitation, incorporating microbiota modifications based on patient-specific factors and surgery type. However, it also notes the need for further research to standardise therapeutic regimens and confirm the safety and efficacy of these interventions in clinical practice.

Polyphenols from Prunus salicina L. alleviate weight gain, obesity-related hyperlipidemia, hepatic steatosis, hyperglycemia, and modulate gut microbiota in mice fed a high-fat diet

Hyperlipidemia, hepatic steatosis, and hyperglycemia are prevalent metabolic disorders closely linked to obesity. The objective of this research was to examine the potential advantageous impacts of polyphenols extracted from Prunus salicina L. fruit (PSFP) on hyperlipidemia, hepatic steatosis, and hyperglycemia induced by a high-fat diet (HFD), as well as to elucidate the underlying mechanisms involved. Male C57BL/6J mice, free from specific pathogens, were assigned randomly into three groups. These groups were then subjected to a 14-week dietary intervention, including a low-fat diet, an HFD, or an HFD plus with PSFP via intragastric administration. The obesity-related biochemical indexes were evaluated. To assess alterations in gut microbiota resulting from PSFP treatment, 16S rRNA sequencing was performed. UPLC-ESI-MS/MS assay identified 162 distinct polyphenolic compounds in PSFP. The administration of PSFP significantly reduced both body weight gain and hyperlipidemia induced by HFD. In addition, PSFP ameliorated hepatic steatosis induced by HFD and enhanced liver function in mice. PSFP treatment also ameliorated HFD-induced insulin resistance and hyperglycemia, evidenced by the observed decrease in fasting serum concentrations of glucose and insulin, improved insulin sensitivity, and restored glucose tolerance. Moreover, PSFP modulated the composition and abundance of specific microbial genus, including Lachnospiraceae NK4A136 group, Akkermansia, Parabacteroides, Enterococcus, Adlercreutzia, and Roseburia. Correlation analysis indicated significant associations between gut microbiota and physiological indices associated with obesity. These findings suggested that PSFP supplementation ameliorated HFD-induced hyperlipidemia, hepatic steatosis, and hyperglycemia, potentially through modulating the gut microbiota composition and abundance of specific taxa.

The Role of Gut Microbiota in the Onset and Progression of Obesity and Associated Comorbidities

Obesity, a global public health problem, is constantly increasing, so the concerns in preventing and combating it are increasingly focused on the intestinal microbiota. It was found that the microbiota is different in lean people compared to obese individuals, but the exact mechanisms by which energy homeostasis is influenced are still incompletely known. Numerous studies show the involvement of certain bacterial species in promoting obesity and associated diseases such as diabetes, hypertension, cancer, etc. Our aim is to summarize the main findings regarding the influence of several factors such as lifestyle changes, including diet and bariatric surgery, on the diversity of the gut microbiota in obese individuals. The second purpose of this paper is to investigate the potential effect of various microbiota modulation techniques on ameliorating obesity and its comorbidities. A literature search was conducted using the PubMed database, identifying articles published between 2019 and 2024. Most studies identified suggest that obesity is generally associated with alterations of the gut microbiome such as decreased microbial diversity, an increased Firmicutes-to-Bacteroidetes ratio, and increased SCFAs levels. Our findings also indicate that gut microbiota modulation techniques could represent a novel strategy in treating obesity and related metabolic diseases. Although some mechanisms (e.g., inflammation or hormonal regulation) are already considered a powerful connection between gut microbiota and obesity development, further research is needed to enhance the knowledge on this particular topic.

Agarooligosaccharides as a novel concept in prebiotics: selective inhibition of Ruminococcus gnavus and Fusobacterium nucleatum while preserving Bifidobacteria, Lactobacillales in vitro, and inhibiting Lachnospiraceae in vivo

Recent studies have linked Ruminococcus gnavus to inflammatory bowel disease and Fusobacterium nucleatum to various cancers. Agarooligosaccharides (AOS), derived from the acid hydrolysis of agar, have shown significant inhibitory effects on the growth of R. gnavus and F. nucleatum at concentrations of 0.1 and 0.2%, respectively. RNA sequencing and quantitative reverse-transcription PCR analyses revealed the downregulation of fatty acid biosynthesis genes (fab genes) in these bacteria when exposed to 0.1% AOS. Furthermore, AOS treatment altered the fatty acid composition of R. gnavus cell membranes, increasing medium-chain saturated fatty acids (C8, C10) and C18 fatty acids while reducing long-chain fatty acids (C14, C16). In contrast, no significant growth inhibition was observed in several strains of Bifidobacteria and Lactobacillales at AOS concentrations of 0.2 and 2%, respectively. Co-culture experiments with R. gnavus and Bifidobacterium longum in 0.2% AOS resulted in B. longum dominating the population, constituting over 96% post-incubation. In vivo studies using mice demonstrated a significant reduction in the Lachnospiraceae family, to which R. gnavus belongs, following AOS administration. Quantitative PCR also showed lower levels of the nan gene, potentially associated with immune disorders, in the AOS group. These findings suggest that AOS may introduce a novel concept in prebiotics by selectively inhibiting potentially pathogenic bacteria while preserving beneficial bacteria such as Bifidobacteria and Lactobacillales.

Maternal immune cell gene expression associates with maternal gut microbiome, milk composition and infant gut microbiome

BACKGROUND

Pre-pregnancy overweight and obesity promote deleterious health impacts on both mothers during pregnancy and the offspring. Significant changes in the maternal peripheral blood mononuclear cells (PBMCs) gene expression due to obesity are well-known. However, the impact of pre-pregnancy overweight on immune cell gene expression during pregnancy and its association with maternal and infant outcomes is not well explored.

METHODS

Blood samples were collected from healthy normal weight (NW, pre-pregnancy BMI 18.5-24.9) or overweight (OW, pre-pregnancy BMI 25-29.9) 2nd parity pregnant women at 12, 24 and 36 weeks of pregnancy. PBMCs were isolated from the blood and subjected to mRNA sequencing. Maternal and infant microbiota were analyzed by 16S rRNA gene sequencing. Integrative multi-omics data analysis was performed to evaluate the association of gene expression with maternal diet, gut microbiota, milk composition, and infant gut microbiota.

RESULTS

Gene expression analysis revealed that 453 genes were differentially expressed in the OW women compared to NW women at 12 weeks of pregnancy, out of which 354 were upregulated and 99 were downregulated. Several up-regulated genes in the OW group were enriched in inflammatory, chemokine-mediated signaling and regulation of interleukin-8 production-related pathways. At 36 weeks of pregnancy healthy eating index score was positively associated with several genes that include, DTD1, ELOC, GALNT8, ITGA6-AS1, KRT17P2, NPW, POT1-AS1 and RPL26. In addition, at 36 weeks of pregnancy, genes involved in adipocyte functions, such as NG2 and SMTNL1, were negatively correlated to human milk 2'FL and total fucosylated oligosaccharides content collected at 1 month postnatally. Furthermore, infant Akkermansia was positively associated with maternal PBMC anti-inflammatory genes that include CPS1 and RAB7B, at 12 and 36 weeks of pregnancy.

CONCLUSIONS

These findings suggest that prepregnancy overweight impacts the immune cell gene expression profile, particularly at 12 weeks of pregnancy. Furthermore, deciphering the complex association of PBMC's gene expression levels with maternal gut microbiome and milk composition and infant gut microbiome may aid in developing strategies to mitigate obesity-mediated effects.

Gut Microbes in Polycystic Ovary Syndrome and Associated Comorbidities; Type 2 Diabetes, Non-Alcoholic Fatty Liver Disease (NAFLD), Cardiovascular Disease (CVD), and the Potential of Microbial Therapeutics

Polycystic ovary syndrome (PCOS) is one of the most common endocrine anomalies among females of reproductive age, highlighted by hyperandrogenism. PCOS is multifactorial as it can be associated with obesity, insulin resistance, low-grade chronic inflammation, and dyslipidemia. PCOS also leads to dysbiosis by lowering microbial diversity and beneficial microbes, such as Faecalibacterium, Roseburia, Akkermenisa, and Bifidobacterium, and by causing a higher load of opportunistic pathogens, such as Escherichia/Shigella, Fusobacterium, Bilophila, and Sutterella. Wherein, butyrate producers and Akkermansia participate in the glucose uptake by inducing glucagon-like peptide-1 (GLP-1) and glucose metabolism, respectively. The abovementioned gut microbes also maintain the gut barrier function and glucose homeostasis by releasing metabolites such as short-chain fatty acids (SCFAs) and Amuc_1100 protein. In addition, PCOS-associated gut is found to be higher in gut-microbial enzyme β-glucuronidase, causing the de-glucuronidation of conjugated androgen, making it susceptible to reabsorption by entero-hepatic circulation, leading to a higher level of androgen in the circulatory system. Overall, in PCOS, such dysbiosis increases the gut permeability and LPS in the systemic circulation, trimethylamine N-oxide (TMAO) in the circulatory system, chronic inflammation in the adipose tissue and liver, and oxidative stress and lipid accumulation in the liver. Thus, in women with PCOS, dysbiosis can promote the progression and severity of type 2 diabetes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular diseases (CVD). To alleviate such PCOS-associated complications, microbial therapeutics (probiotics and fecal microbiome transplantation) can be used without any side effects, unlike in the case of hormonal therapy. Therefore, this study sought to understand the mechanistic significance of gut microbes in PCOS and associated comorbidities, along with the role of microbial therapeutics that can ease the life of PCOS-affected women.

The Gut Microbiota Impacts Gastrointestinal Cancers through Obesity, Diabetes, and Chronic Inflammation

The gut microbiota's pivotal role in human health is increasingly evident, particularly in chronic conditions like obesity, diabetes, and inflammatory diseases. This intricate symbiotic relationship influences metabolic balance and immune responses. Notably, gut microbial dysbiosis is linked to obesity's metabolic disruption and chronic low-grade inflammation. Similarly, in diabetes, the microbiota's impact on insulin resistance and glucose metabolism is becoming evident. Chronic inflammation, a common denominator in these conditions, is also a recognized precursor to carcinogenesis. This intersection prompts a compelling question: does the gut microbiota's influence extend to gastrointestinal cancers like colorectal and pancreatic cancer? These malignancies are closely intertwined with inflammation and metabolic dysregulation. Exploring whether the microbial signatures associated with chronic conditions overlap with precancerous or cancerous states offers new perspectives. This article reviews emerging evidence on the interplay between the gut microbiota, chronic conditions, and gastrointestinal cancers. By elucidating these connections, we aim to uncover potential avenues for innovative diagnostic, preventative, and therapeutic strategies in colorectal and pancreatic cancer management.

The Gut Microbiota and Diabetes: Research, Translation, and Clinical Applications-2023 Diabetes, Diabetes Care, and Diabetologia Expert Forum

This article summarizes the state of the science on the role of the gut microbiota (GM) in diabetes from a recent international expert forum organized by Diabetes, Diabetes Care, and Diabetologia, which was held at the European Association for the Study of Diabetes 2023 Annual Meeting in Hamburg, Germany. Forum participants included clinicians and basic scientists who are leading investigators in the field of the intestinal microbiome and metabolism. Their conclusions were as follows: 1) the GM may be involved in the pathophysiology of type 2 diabetes, as microbially produced metabolites associate both positively and negatively with the disease, and mechanistic links of GM functions (e.g., genes for butyrate production) with glucose metabolism have recently emerged through the use of Mendelian randomization in humans; 2) the highly individualized nature of the GM poses a major research obstacle, and large cohorts and a deep-sequencing metagenomic approach are required for robust assessments of associations and causation; 3) because single-time point sampling misses intraindividual GM dynamics, future studies with repeated measures within individuals are needed; and 4) much future research will be required to determine the applicability of this expanding knowledge to diabetes diagnosis and treatment, and novel technologies and improved computational tools will be important to achieve this goal.

The gut microbiota and diabetes: research, translation, and clinical applications - 2023 Diabetes, Diabetes Care, and Diabetologia Expert Forum

This article summarises the state of the science on the role of the gut microbiota (GM) in diabetes from a recent international expert forum organised by Diabetes, Diabetes Care, and Diabetologia, which was held at the European Association for the Study of Diabetes 2023 Annual Meeting in Hamburg, Germany. Forum participants included clinicians and basic scientists who are leading investigators in the field of the intestinal microbiome and metabolism. Their conclusions were as follows: (1) the GM may be involved in the pathophysiology of type 2 diabetes, as microbially produced metabolites associate both positively and negatively with the disease, and mechanistic links of GM functions (e.g. genes for butyrate production) with glucose metabolism have recently emerged through the use of Mendelian randomisation in humans; (2) the highly individualised nature of the GM poses a major research obstacle, and large cohorts and a deep-sequencing metagenomic approach are required for robust assessments of associations and causation; (3) because single time point sampling misses intraindividual GM dynamics, future studies with repeated measures within individuals are needed; and (4) much future research will be required to determine the applicability of this expanding knowledge to diabetes diagnosis and treatment, and novel technologies and improved computational tools will be important to achieve this goal.

The Gut Microbiota and Diabetes: Research, Translation, and Clinical Applications-2023 Diabetes, Diabetes Care, and Diabetologia Expert Forum

This article summarizes the state of the science on the role of the gut microbiota (GM) in diabetes from a recent international expert forum organized by Diabetes, Diabetes Care, and Diabetologia, which was held at the European Association for the Study of Diabetes 2023 Annual Meeting in Hamburg, Germany. Forum participants included clinicians and basic scientists who are leading investigators in the field of the intestinal microbiome and metabolism. Their conclusions were as follows: 1) the GM may be involved in the pathophysiology of type 2 diabetes, as microbially produced metabolites associate both positively and negatively with the disease, and mechanistic links of GM functions (e.g., genes for butyrate production) with glucose metabolism have recently emerged through the use of Mendelian randomization in humans; 2) the highly individualized nature of the GM poses a major research obstacle, and large cohorts and a deep-sequencing metagenomic approach are required for robust assessments of associations and causation; 3) because single-time point sampling misses intraindividual GM dynamics, future studies with repeated measures within individuals are needed; and 4) much future research will be required to determine the applicability of this expanding knowledge to diabetes diagnosis and treatment, and novel technologies and improved computational tools will be important to achieve this goal.

Modulation of Poultry Cecal Microbiota by a Phytogenic Blend and High Concentrations of Casein in a Validated In Vitro Cecal Chicken Alimentary Tract Model

Phytogenic blends (PBs) consist of various bioactive plant-derived compounds that are used as growth promoters for farm animals. Feed additives based on PBs have beneficial effects on farm animals' production performance, health, and overall well-being, as well as positive modulating effects on gut microbiota. In this study, we used a validated in vitro cecal chicken alimentary tract model (CALIMERO-2) to evaluate the effects of a PB (a mix of components found in rosemary, cinnamon, curcuma, oregano oil, and red pepper), alone or in combination with casein (control), on poultry cecal microbiota. Supplementation with the PB significantly increased the abundance of bacteria associated with energy metabolism (Monoglobus) and growth performance in poultry (Lachnospiraceae UCG-010). The PB also decreased the abundance of opportunistic pathogens (Escherichia-Shigella) and, most importantly, did not promote other opportunistic pathogens, which indicates the safety of this blend for poultry. In conclusion, the results of this study show promising perspectives on using PBs as feed additives for poultry, although further in vivo studies need to prove these data.

The Effect of the Lacticaseibacillus paracasei BEPC22 and Lactiplantibacillus plantarum BELP53 Combination (BN-202M) on Body Fat Percentage Loss in Overweight Individuals: A Randomized, Double-Blind, Placebo-Controlled Study

BN-202M is derived from humans and consists of two strains, Lacticaseibacillus paracasei BEPC22 and Lactiplantibacillus plantarum BELP53. Body fat reduction effect and safety of BN-202M were assessed in overweight participants. A total of 150 participants were randomly assigned to the BN-202M and placebo groups at a 1:1 ratio. Dual-energy X-ray absorptiometry was used to objectively measure body fat. After 12 weeks of oral administration, the body fat percentage (-0.10 ± 1.32% vs. 0.48 ± 1.10%; p = 0.009) and body fat mass (-0.24 ± 1.19 kg vs. 0.23 ± 1.05 kg; p = 0.023) of the BN-202M group decreased significantly compared to those of the placebo group. The body weight (-0.58 kg, p = 0.004) and body mass index (BMI; -0.23, p = 0.003) was found to decrease significantly at 12 weeks in the BN-202M group, but not in the placebo group. Metabolome analysis revealed that β-alanine, 3-aminoisobutyric acid, glutamic acid, and octopamine decreased in the weight-decreased BN-202M post-intake group. In the gut microbiota analysis, Akkermansia showed a statistically significant increase in the BN-202M group post-intake compared to the placebo group. No serious adverse events were observed in either group. These results suggest that BN-202M is safe and effective for reducing body fat and weight.

Association between Gut Microbiota and Inflammation: Mediation Analysis Using Waist Circumference

Chronic low-grade inflammation (CLI) is implicated in the development of multiple metabolic diseases. The gut microbiota (GM) activates different signaling pathways and induces phenotypic changes, offering an exciting opportunity to treat CLI. We evaluated the mediation of waist circumference on the association of GM with serum cytokines. In this cross-sectional study of 331 children, we measured 5 gut bacterial species, namely, Lactobacillus (L.) casei, L. paracasei, L. reuteri, Staphylococcus (S.) aureus, and Akkermansia (A.) muciniphila, as well as anthropometry, serum cytokines, and other covariates. We evaluated adjusted regression models, path analysis, and structural equation modeling to obtain path coefficients (PCs) for direct, indirect (waist circumference-mediated), and total effects. We found that L. paracasei was directly associated with lower interleukin-10 (IL-10) levels (PC = -173.5 pg/mL). We also observed indirect associations between S. aureus with lower adiponectin levels (PC = -0.1 µg/mL and -0.09 µg/mL). Finally, A. muciniphila was indirectly associated with higher adiponectin levels (PC = 0.1 µg/mL). Our findings suggest the importance of considering the GM composition and waist circumference when evaluating inflammatory-related factors, providing a basis for future research to identify potential strategies to intervene in inflammatory processes and prevent metabolic diseases in childhood. [Figure: see text].

Spatial profiles of the bacterial microbiota throughout the gastrointestinal tract of dairy goats

The gastrointestinal tract (GIT) is stationed by a dynamic and complex microbial community with functions in digestion, metabolism, immunomodulation, and reproduction. However, there is relatively little research on the composition and function of microorganisms in different GIT segments in dairy goats. Herein, 80 chyme samples were taken from ten GIT sites of eight Xinong Saanen dairy goats and then analyzed and identified the microbial composition via 16S rRNA V1-V9 amplicon sequencing. A total of 6669 different operational taxonomic units (OTUs) were clustered, and 187 OTUs were shared by ten GIT segments. We observed 264 species belonging to 23 different phyla scattered across ten GITs, with Firmicutes (52.42%) and Bacteroidetes (22.88%) predominating. The results revealed obvious location differences in the composition, diversity, and function of the GIT microbiota. In LEfSe analysis, unidentified_Lachnospiraceae and unidentified_Succinniclassicum were significantly enriched in the four chambers of stomach, with functions in carbohydrate fermentation to compose short-chain fatty acids. Aeriscardovia, Candidatus_Saccharimonas, and Romboutsia were significantly higher in the foregut, playing an important role in synthesizing enzymes, amino acids, and vitamins and immunomodulation. Akkermansia, Bacteroides, and Alistipes were significantly abundant in the hindgut to degrade polysaccharides and oligosaccharides, etc. From rumen to rectum, α-diversity decreased first and then increased, while β-diversity showed the opposite trend. Metabolism was the major function of the GIT microbiome predicted by PICRUSt2, but with variation in target substrates along the regions. In summary, GIT segments play a decisive role in the composition and functions of microorganisms. KEY POINTS: • The jejunum and ileum were harsh for microorganisms to colonize due to the presence of bile acids, enzymes, faster chyme circulation, etc., exhibiting the lowest α-diversity and the highest β-diversity. • Variability in microbial profiles between the three foregut segments was greater than four chambers of stomach and hindgut, with a higher abundance of Firmicutes dominating than others. • Dairy goats dominated a higher abundance of Kiritimatiellaeota than cows, which was reported to be associated with fatty acid synthesis.

The Effect of Clostridium butyricum on Gut Microbial Changes and Functional Profiles of Metabolism in High-fat Diet-fed Rats Depending on Age and Sex

Background/Aims

A high-fat diet (HFD) causes dysbiosis and promotes inflammatory responses in the colon. This study aims to evaluate the effects of Clostridium butyricum on HFD-induced gut microbial changes in rats.

Methods

Six-week-old Fischer-344 rats with both sexes were given a control or HFD during 8 weeks, and 1-to-100-fold diluted Clostridium butyricum were administered by gavage. Fecal microbiota analyses were conducted using 16S ribosomal RNA metagenomic sequencing and predictive functional profiling of microbial communities in metabolism.

Results

A significant increase in Ruminococcaceae and Lachnospiraceae, which are butyric acid-producing bacterial families, was observed in the probiotics groups depending on sex. In contrast, Akkermansia muciniphila, which increased through a HFD regardless of sex, and decreased in the probiotics groups. A. muciniphila positively correlated with Claudin-1 expression in males (P < 0.001) and negatively correlated with the expression of Claudin-2 (P = 0.042), IL-1β (P = 0.037), and IL-6 (P = 0.044) in females. In terms of functional analyses, a HFD decreased the relative abundances of M00131 (carbohydrate metabolism module), M00579, and M00608 (energy metabolism), and increased those of M00307 (carbohydrate metabolism), regardless of sex. However, these changes recovered especially in male C. butyricum groups. Furthermore, M00131, M00579, and M00608 showed a positive correlation and M00307 showed a negative correlation with the relative abundance of A. muciniphila (P < 0.001).

Conclusion

The beneficial effects of C. butyricum on HFD-induced gut dysbiosis in young male rats originate from the functional profiles of carbohydrate and energy metabolism.

Gut microbiota composition is associated with the efficacy of Delta-24-RGDOX in malignant gliomas

Glioblastoma, the most common primary brain tumor, has a 6.8% survival rate 5 years post diagnosis. Our team developed an oncolytic adenovirus with an OX-40L expression cassette named Delta-24-RGDOX. While studies have revealed the interaction between the gut microbiota and immunotherapy agents, there are no studies linking the gut microbiota with viroimmunotherapy efficacy. We hypothesize that gut bacterial signatures will be associated with oncolytic viral therapy efficacy. To test this hypothesis, we evaluated the changes in gut microbiota in two mouse cohorts: (1) GSC-005 glioblastoma-bearing mice treated orally with indoximod, an immunotherapeutic agent, or with Delta-24-RGDOX by intratumoral injection and (2) a mouse cohort harboring GL261-5 tumors used to mechanistically evaluate the importance of CD4+ T cells in relation to viroimmunotherapy efficacy. Microbiota assessment indicated significant differences in the structure of the gut bacterial communities in viroimmunotherapy-treated animals with higher survival compared with control or indoximod-treated animals. Moreover, viroimmunotherapy-treated mice with prolonged survival had a higher abundance of Bifidobacterium. The CD4+ T cell depletion was associated with gut dysbiosis, lower mouse survival, and lower antitumor efficacy of the therapy. These findings suggest that microbiota modulation along the gut-glioma axis contributes to the clinical efficacy and patient survival of viroimmunotherapy treated animals.

Multi-omics analysis of the gut microbiome and metabolites associated with the psychoneurological symptom cluster in children with cancer receiving chemotherapy

BACKGROUND

Children with cancer receiving chemotherapy commonly report a cluster of psychoneurological symptoms (PNS), including pain, fatigue, anxiety, depression, and cognitive dysfunction. The role of the gut microbiome and its functional metabolites in PNS is rarely studied among children with cancer. This study investigated the associations between the gut microbiome-metabolome pathways and PNS in children with cancer across chemotherapy as compared to healthy children.

METHODS

A case-control study was conducted. Cancer cases were recruited from Children's Healthcare of Atlanta and healthy controls were recruited via flyers. Participants reported PNS using the Pediatric Patient-Reported Outcomes Measurement Information System. Data for cases were collected pre-cycle two chemotherapy (T0) and post-chemotherapy (T1), whereas data for healthy controls were collected once. Gut microbiome and its metabolites were measured using fecal specimens. Gut microbiome profiling was performed using 16S rRNA V4 sequencing, and metabolome was performed using an untargeted liquid chromatography-mass spectrometry approach. A multi-omics network integration program analyzed microbiome-metabolome pathways of PNS.

RESULTS

Cases (n = 21) and controls (n = 14) had mean ages of 13.2 and 13.1 years. For cases at T0, PNS were significantly associated with microbial genera (e.g., Ruminococcus, Megasphaera, and Prevotella), which were linked with carnitine shuttle (p = 0.0003), fatty acid metabolism (p = 0.001) and activation (p = 0.001), and tryptophan metabolism (p = 0.008). Megasphaera, clustered with aspartate and asparagine metabolism (p = 0.034), carnitine shuttle (p = 0.002), and tryptophan (p = 0.019), was associated with PNS for cases at T1. Gut bacteria with potential probiotic functions, along with fatty acid metabolism, tryptophan, and carnitine shuttle, were more clustered in cancer cases than the control network and this linkage with PNS needs further studies.

CONCLUSIONS

Using multi-omics approaches, this study indicated specific microbiome-metabolome pathways linked with PNS in children with cancer across chemotherapy. Due to limitations such as antibiotic use in cancer cases, these findings need to be further confirmed in a larger cohort.

Impact of metformin and Dysosmobacter welbionis on diet-induced obesity and diabetes: from clinical observation to preclinical intervention

AIMS/HYPOTHESIS

We aimed to investigate the association between the abundance of Dysosmobacter welbionis, a commensal gut bacterium, and metabolic health in human participants with obesity and diabetes, and the influence of metformin treatment and prebiotic intervention.

METHODS

Metabolic variables were assessed and faecal samples were collected from 106 participants in a randomised controlled intervention with a prebiotic stratified by metformin treatment (Food4Gut trial). The abundance of D. welbionis was measured by quantitative PCR and correlated with metabolic markers. The in vitro effect of metformin on D. welbionis growth was evaluated and an in vivo study was performed in mice to investigate the effects of metformin and D. welbionis J115T supplementation, either alone or in combination, on metabolic variables.

RESULTS

D. welbionis abundance was unaffected by prebiotic treatment but was significantly higher in metformin-treated participants. Responders to prebiotic treatment had higher baseline D. welbionis levels than non-responders. D. welbionis was negatively correlated with aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and fasting blood glucose levels in humans with obesity and type 2 diabetes. In vitro, metformin had no direct effect on D. welbionis growth. In mice, D. welbionis J115T treatment reduced body weight gain and liver weight, and improved glucose tolerance to a better level than metformin, but did not have synergistic effects with metformin.

CONCLUSIONS/INTERPRETATION

D. welbionis abundance is influenced by metformin treatment and associated with prebiotic response, liver health and glucose metabolism in humans with obesity and diabetes. This study suggests that D. welbionis may play a role in metabolic health and warrants further investigation.

CLINICAL TRIAL

NCT03852069.

Meta-analysis reveals obesity associated gut microbial alteration patterns and reproducible contributors of functional shift

The majority of cohort-specific studies associating gut microbiota with obesity are often contradictory; thus, the replicability of the signature remains questionable. Moreover, the species that drive obesity-associated functional shifts and their replicability remain unexplored. Thus, we aimed to address these questions by analyzing gut microbial metagenome sequencing data to develop an in-depth understanding of obese host-gut microbiota interactions using 3329 samples (Obese, n = 1494; Control, n = 1835) from 17 different countries, including both 16S rRNA gene and metagenomic sequence data. Fecal metagenomic data from diverse geographical locations were curated, profiled, and pooled using a machine learning-based approach to identify robust global signatures of obesity. Furthermore, gut microbial species and pathways were systematically integrated through the genomic content of the species to identify contributors to obesity-associated functional shifts. The community structure of the obese gut microbiome was evaluated, and a reproducible depletion of diversity was observed in the obese compared to the lean gut. From this, we infer that the loss of diversity in the obese gut is responsible for perturbations in the healthy microbial functional repertoire. We identified 25 highly predictive species and 37 pathway associations as signatures of obesity, which were validated with remarkably high accuracy (AUC, Species: 0.85, and pathway: 0.80) with an independent validation dataset. We observed a reduction in short-chain fatty acid (SCFA) producers (several Alistipes species, Odoribacter splanchnicus, etc.) and depletion of promoters of gut barrier integrity (Akkermansia muciniphila and Bifidobacterium longum) in obese guts. Our analysis underlines SCFAs and purine/pyrimidine biosynthesis, carbohydrate metabolism pathways in control individuals, and amino acid, enzyme cofactor, and peptidoglycan biosynthesis pathway enrichment in obese individuals. We also mapped the contributors to important obesity-associated functional shifts and observed that these are both dataset-specific and shared across the datasets. In summary, a comprehensive analysis of diverse datasets unveils species specifically contributing to functional shifts and consistent gut microbial patterns associated to obesity.

Characterizing alterations in the gut microbiota following postpartum weight change

IMPORTANCE

Previous research has reported differences in the gut microbiome associated with varying body compositions. More specifically, within populations of mothers, the focus has been on the impact of gestational weight gain. This is the first study to examine postpartum weight change and its association with changes in the gut microbiome, similarly, it is the first to use a Latina cohort to do so. The results support the idea that weight gain may be an important factor in reducing gut microbiome network connectivity, diversity, and changing abundances of specific microbial taxa, all measures thought to impact host health. These results suggest that weight gain dynamically alters mothers' gut microbial communities in the first 6 months postpartum, with comparatively little change in mothers who lost weight; further research is needed to examine the health consequences of such changes.

Akkermansia muciniphila promotes testosterone-mediated hair growth inhibition in mice

The beneficial effects of Akkermansia muciniphila (Akk) on gut health and inflammation reduction have been demonstrated; however, scientific evidence of hair growth enhancement by Akk has not been reported. Therefore, this study was undertaken to investigate the effect of Akk on improving testosterone-mediated hair growth inhibition. Hair growth inhibition was induced through subcutaneous injection of testosterone into the shaved dorsal skin of C57BL/6 male mice. Live and pasteurized Akk were orally administered at a concentration of 1 × 108 colony-forming unit. After 5 weeks, hair length and skin tissues were analyzed. The live and pasteurized Akk significantly stimulated hair growth, countering the inhibitory effect of testosterone compared to the testosterone-alone group. Hematoxylin and eosin staining revealed a significant increase in hair follicle size in the Akk-treated group. An increase in β-catenin levels, which are associated with hair growth and cell cycle progression, was also observed. Moreover, the Akk-treated group exhibited increased levels of fibroblast growth factors, including Fgf7, Igf1, Fgf7, Fgf10, and Fgf21. However, no significant difference was observed between the live and pasteurized Akk groups. These results underscore the potential of live and pasteurized Akk in improving testosterone-mediated hair growth inhibition.

Interaction between Akkermansia muciniphila and Diet Is Associated with Proinflammatory Index in School-Aged Children

BACKGROUND

Imbalance in the intestinal microbiota can lead to chronic low-grade inflammation. Diet may influence this association. In this study, we aimed to evaluate the interaction between Akkermansia muciniphila (A. muciniphila) and dietary patterns using a proinflammatory index.

METHODS

We conducted a cross-sectional study with school-aged children. We quantified the relative abundance (RA) of A. muciniphila in feces using a polymerase chain reaction. We collected dietary information through employing a food frequency questionnaire and generated dietary patterns using principal component analysis. We generated a proinflammatory index from serum levels of interleukin-6, interleukin-10, tumor necrosis factor alpha, and adiponectin validated by receptor operating characteristic curves. We evaluated the association between A. muciniphila and the proinflammatory index using logistic regression, including an interaction term with dietary patterns.

RESULTS

We found that children with a low RA of A. muciniphila and a high intake of simple carbohydrates and saturated fats had increased odds of being high on the proinflammatory index. However, when the consumption of this dietary pattern is low, children with a low RA of A. muciniphila had decreased odds of being high on the proinflammatory index.

CONCLUSIONS

Our results suggest that the simultaneous presence of A. muciniphila and diet have a more significant impact on the presence of being high on the proinflammatory index compared to both factors separately.

The microbiome-gut-brain axis in nutritional neuroscience

Emerging evidence is highlighting the microbiome as a key regulator of the effect of nutrition on gut-brain axis signaling. Nevertheless, it is not yet clear whether the impact of nutrition is moderating the microbiota-gut-brain interaction or if diet has a mediating role on microbiota composition and function to influence central nervous system function, brain phenotypes and behavior. Mechanistic evidence from cell-based in vitro studies, animal models and preclinical intervention studies are linking the gut microbiota to the effects of diet on brain function, but they have had limited translation to human intervention studies. While increasing evidence demonstrates the triangulating relationship between diet, microbiota, and brain function across the lifespan, future mechanistic and translational studies in the field of microbiota and nutritional neuroscience are warranted to inform potential strategies for prevention and management of several neurological, neurodevelopmental, neurodegenerative, and psychiatric disorders. This brief primer provides an overview of the most recent advances in the nutritional neuroscience - microbiome field, highlighting significant opportunities for future research.

From-Toilet-to-Freezer: A Review on Requirements for an Automatic Protocol to Collect and Store Human Fecal Samples for Research Purposes

The composition, viability and metabolic functionality of intestinal microbiota play an important role in human health and disease. Studies on intestinal microbiota are often based on fecal samples, because these can be sampled in a non-invasive way, although procedures for sampling, processing and storage vary. This review presents factors to consider when developing an automated protocol for sampling, processing and storing fecal samples: donor inclusion criteria, urine-feces separation in smart toilets, homogenization, aliquoting, usage or type of buffer to dissolve and store fecal material, temperature and time for processing and storage and quality control. The lack of standardization and low-throughput of state-of-the-art fecal collection procedures promote a more automated protocol. Based on this review, an automated protocol is proposed. Fecal samples should be collected and immediately processed under anaerobic conditions at either room temperature (RT) for a maximum of 4 h or at 4 °C for no more than 24 h. Upon homogenization, preferably in the absence of added solvent to allow addition of a buffer of choice at a later stage, aliquots obtained should be stored at either -20 °C for up to a few months or -80 °C for a longer period-up to 2 years. Protocols for quality control should characterize microbial composition and viability as well as metabolic functionality.

Gut microbiota analyses of inflammatory bowel diseases from a representative Saudi population

BACKGROUND

Crohn's diseases and ulcerative colitis, both of which are chronic immune-mediated disorders of the gastrointestinal tract are major contributors to the overarching Inflammatory bowel diseases. It has become increasingly evident that the pathological processes of IBDs results from interactions between genetic and environmental factors, which can skew immune responses against normal intestinal flora.

METHODS

The aim of this study is to assess and analyze the taxa diversity and relative abundances in CD and UC in the Saudi population. We utilized a sequencing strategy that targets all variable regions in the 16 S rRNA gene using the Swift Amplicon 16 S rRNA Panel on Illumina NovaSeq 6000.

RESULTS

The composition of stool 16 S rRNA was analyzed from 219 patients with inflammatory bowel disease and from 124 healthy controls. We quantified the abundance of microbial communities to examine any significant differences between subpopulations of samples. At the genus level, two genera in particular, Veillonella and Lachnoclostridium showed significant association with CD versus controls. There were significant differences between subjects with CD versus UC, with the top differential genera spanning Akkermansia, Harryflintia, Maegamonas and Phascolarctobacterium. Furthermore, statistically significant taxa diversity in microbiome composition was observed within the UC and CD groups.

CONCLUSIONS

In conclusion we have shown that there are significant differences in gut microbiota between UC, CD and controls in a Saudi Arabian inflammatory bowel disease cohort. This reinforces the need for further studies in large populations that are ethnically and geographically diverse. In addition, our results show the potential to develop classifiers that may have add additional richness of context to clinical diagnosis of UC and CD with larger inflammatory bowel disease cohorts.

Short-chain fatty acids, secondary bile acids and indoles: gut microbial metabolites with effects on enteroendocrine cell function and their potential as therapies for metabolic disease

The gastrointestinal tract hosts the largest ecosystem of microorganisms in the body. The metabolism of ingested nutrients by gut bacteria produces novel chemical mediators that can influence chemosensory cells lining the gastrointestinal tract. Specifically, hormone-releasing enteroendocrine cells which express a host of receptors activated by these bacterial metabolites. This review will focus on the activation mechanisms of glucagon-like peptide-1 releasing enteroendocrine cells by the three main bacterial metabolites produced in the gut: short-chain fatty acids, secondary bile acids and indoles. Given the importance of enteroendocrine cells in regulating glucose homeostasis and food intake, we will also discuss therapies based on these bacterial metabolites used in the treatment of metabolic diseases such as diabetes and obesity. Elucidating the mechanisms gut bacteria can influence cellular function in the host will advance our understanding of this fundamental symbiotic relationship and unlock the potential of harnessing these pathways to improve human health.

Intestinal Epithelial Inactivity of Dual Oxidase 2 Results in Microbiome-Mediated Metabolic Syndrome

BACKGROUND & AIMS

Metabolic syndrome (MetS) is characterized by obesity, glucose intolerance, and hepatic steatosis. Alterations in the gut microbiome play important roles in the development of MetS. However, the mechanisms by which this occurs are poorly understood. Dual oxidase 2 (DUOX2) is an antimicrobial reduced nicotinamide adenine dinucleotide phosphate oxidase expressed in the gut epithelium. Here, we posit that epithelial DUOX2 activity provides a mechanistic link between the gut microbiome and the development of MetS.

METHODS

Mice carrying an intestinal epithelial-specific deletion of dual oxidase maturation factor 1/2 (DA IEC-KO), and wild-type littermates were fed a standard diet and killed at 24 weeks. Metabolic alterations were determined by glucose tolerance, lipid tests, and body and organ weight measurements. DUOX2 activity was determined by Amplex Red. Intestinal permeability was determined by fluorescein isothiocyanate-dextran, microbial translocation assessments, and portal vein lipopolysaccharide measurements. Metagenomic analysis of the stool microbiome was performed. The role of the microbiome was assessed in antibiotic-treated mice.

RESULTS

DA IEC-KO males showed increased body and organ weights accompanied by glucose intolerance and increased plasma lipid and liver enzyme levels, and increased adiposity in the liver and adipose tissue. Expression of F4/80, CD68, uncoupling protein 1, carbohydrate response element binding protein, leptin, and adiponectin was altered in the liver and adipose tissue of DA IEC-KO males. DA IEC-KO males produced less epithelial H2O2, had altered relative abundance of Akkermansiaceae and Lachnospiraceae in stool, and showed increased portal vein lipopolysaccharides and intestinal permeability. Females were protected from barrier defects and MetS, despite producing less H2O2. Antibiotic depletion abrogated all MetS phenotypes observed.

CONCLUSIONS

Intestinal epithelial inactivity of DUOX2 promotes MetS in a microbiome-dependent manner.

Potential role of gut microbes in the efficacy and toxicity of immune checkpoints inhibitors

In recent years, Immune checkpoint inhibitors have been extensively used in the treatment of a variety of cancers. However, the response rates ranging from 13% to 69% depending on the tumor type and the emergence of immune-related adverse events have posed significant challenges for clinical treatment. As a key environmental factor, gut microbes have a variety of important physiological functions such as regulating intestinal nutrient metabolism, promoting intestinal mucosal renewal, and maintaining intestinal mucosal immune activity. A growing number of studies have revealed that gut microbes further influence the anticancer effects of tumor patients through modulation of the efficacy and toxicity of immune checkpoint inhibitors. Currently, faecal microbiota transplantation (FMT) have been developed relatively mature and suggested as an important regulator in order to enhance the efficacy of treatment. This review is dedicated to exploring the impact of differences in flora composition on the efficacy and toxicity of immune checkpoint inhibitors as well as to summarizing the current progress of FMT.

Analysis of gut microbiota in patients with Williams-Beuren Syndrome reveals dysbiosis linked to clinical manifestations

Williams-Beuren syndrome (WBS) is a multisystem genetic disease caused by the deletion of a region of 1.5-1.8 Mb on chromosome 7q11.23. The elastin gene seems to account for several comorbidities and distinct clinical features such including cardiovascular disease, connective tissue abnormalities, growth retardation, and gastrointestinal (GI) symptoms. Increasing evidence points to alterations in gut microbiota composition as a primary or secondary cause of some GI or extra-intestinal characteristics. In this study, we performed the first exploratory analysis of gut microbiota in WBS patients compared to healthy subjects (CTRLs) using 16S rRNA amplicon sequencing, by investigating the gut dysbiosis in relation to diseases and comorbidities. We found that patients with WBS have significant dysbiosis compared to age-matched CTRLs, characterized by an increase in proinflammatory bacteria such as Pseudomonas, Gluconacetobacter and Eggerthella, and a reduction of anti-inflammatory bacteria including Akkermansia and Bifidobacterium. Microbial biomarkers associated with weight gain, GI symptoms and hypertension were identified. Gut microbiota profiling could represent a new tool that characterise intestinal dysbiosis to complement the clinical management of these patients. In particular, the administration of microbial-based treatments, alongside traditional therapies, could help in reducing or preventing the burden of these symptoms and improve the quality of life of these patients.

The Impact of a Very-Low-Calorie Ketogenic Diet in the Gut Microbiota Composition in Obesity

The very-low-calorie KD (VLCKD) is characterized by a caloric intake of under 800 kcal/day divided into less than 50 g/day of carbohydrate (13%) and 1 to 1.5 g of protein/kg of body weight (44%) and 43% of fat. This low carbohydrate intake changes the energy source from glucose to ketone bodies. Moreover, clinical trials have consistently shown a beneficial effect of VLCKD in several diseases, such as heart failure, schizophrenia, multiple sclerosis, Parkinson's, and obesity, among others. The gut microbiota has been associated with the metabolic conditions of a person and is regulated by diet interactions; furthermore, it has been shown that the microbiota has a role in body weight homeostasis by regulating metabolism, appetite, and energy. Currently, there is increasing evidence of an association between gut microbiota dysbiosis and the pathophysiology of obesity. In addition, the molecular pathways, the role of metabolites, and how microbiota modulation could be beneficial remain unclear, and more research is needed. The objective of the present article is to contribute with an overview of the impact that VLCKD has on the intestinal microbiota composition of individuals with obesity through a literature review describing the latest research regarding the topic and highlighting which bacteria phyla are associated with obesity and VLCKD.

Effects of fenbendazole on fecal microbiome in BPH/5 mice, a model of hypertension and obesity, a brief report

Fenbendazole (FBZ) is a common antiparasitic treatment used in research rodent colonies for biosecurity purposes. The effect of this compound has been studied in C57 mice, but never before in a strain of mice that has co-morbidities, such as the blood pressure high (BPH)/5. The BPH/5 mouse is an inbred genetic model of hypertension. While both male and female BPH/5 have high blood pressure, there is a metabolic sexual dimorphism with females displaying key features of obesity. The obese gut microbiome has been linked to hypertension. Therefore, we hypothesized that fenbendazole treatment will alter the gut microbiome in hypertensive mice in a sex dependent manner. To test the influence of FBZ on the BPH/5 gut microbiota, fecal samples were collected pre- and post-treatment from adult BPH/5 mice (males and non-pregnant females). The mice were treated with fenbendazole impregnated feed for five weeks. Post-treatment feces were collected at the end of the treatment period and DNA was extracted, and the V4 region of 16S rRNA was amplified and sequenced using the Illumina MiSeq system. The purpose was to analyze the fecal microbiome before and after FBZ treatment, the results demonstrate changes with treatment in a sex dependent manner. More specifically, differences in community composition were detected in BPH/5 non-pregnant female and males using Bray-Curtis dissimilarity as a measure of beta-diversity (treatment p = 0.002). The ratio of Firmicutes to Bacteroidetes, which has been identified in cases of obesity, was not altered. Yet, Verrucomicrobia was increased in BPH/5 males and females post-treatment and was significantly different by sex (treatment p = 5.85e-05, sex p = 0.0151, and interaction p = 0.045), while Actinobacteria was decreased in the post-treatment mice (treatment p = 0.00017, sex p = 0.5, interaction p = 0.2). These results are indicative of gut dysbiosis compared to pre-treatment controls. Lactobacillus was decreased with FBZ treatment in BPH/5 females only. In conclusion, fenbendazole does alter the gut microbial communities, most notable in the male rather than female BPH/5 mouse. This provides evidence that caution should be taken when providing any gut altering treatments before or during mouse experiments.

Collagen Peptide Exerts an Anti-Obesity Effect by Influencing the Firmicutes/Bacteroidetes Ratio in the Gut

Alterations in the intestinal microbial flora are known to cause various diseases, and many people routinely consume probiotics or prebiotics to balance intestinal microorganisms and the growth of beneficial bacteria. In this study, we selected a peptide from fish (tilapia) skin that induces significant changes in the intestinal microflora of mice and reduces the Firmicutes/Bacteroidetes ratio, which is linked to obesity. We attempted to verify the anti-obesity effect of selected fish collagen peptides in a high-fat-diet-based obese mouse model. As anticipated, the collagen peptide co-administered with a high-fat diet significantly inhibited the increase in the Firmicutes/Bacteroidetes ratio. It increased specific bacterial taxa, including Clostridium_sensu_stricto_1, Faecalibaculum, Bacteroides, and Streptococcus, known for their anti-obesity effects. Consequently, alterations in the gut microbiota resulted in the activation of metabolic pathways, such as polysaccharide degradation and essential amino acid synthesis, which are associated with obesity inhibition. In addition, collagen peptide also effectively reduced all obesity signs caused by a high-fat diet, such as abdominal fat accumulation, high blood glucose levels, and weight gain. Ingestion of collagen peptides derived from fish skin induced significant changes in the intestinal microflora and is a potential auxiliary therapeutic agent to suppress the onset of obesity.