The Role of the Gut Microbiota in the Relationship Between Diet and Human Health

Harnessing gut microbial communities to unravel microbiome functions

The gut microbiome impacts human health in direct and indirect ways. While many associations have been discovered between specific microbiome compositions and diseases, establishing causality, understanding the underlying mechanisms, and developing successful microbiome-based therapies require novel experimental approaches. In this opinion, we discuss how in vitro cultivation of diverse communities enables systematic investigation of the individual and collective functions of gut microbes. Up to now, the field has relied mostly on simple, bottom-up assembled synthetic communities or more complex, undefined stool-derived communities. Although powerful for dissecting interactions and mapping causal effects, these communities suffer either from ignoring the complexity, diversity, coevolution, and dynamics of natural communities or from lack of control of community composition. These limitations can be overcome in the future by establishing personalized culture collections from stool samples of different donors and assembling personalized communities to investigate native interactions and ecological relationships in a controlled manner.

Modulation of Gut Microbiota by the Complex of Caffeic Acid and Corn Starch

To understand the impact of different types of polyphenol-starch complexes on digestibility and gut microbiota, caffeic acid (CA) and corn starch (CS) complexes were prepared by coheating and high-pressure homogenization. The resistant starch content in CS coheated with CA (HCS-CA) and HCS-CA after high-pressure homogenization (HCS-CA-HPH) was 47.75 and 56.65%, respectively. Fourier transform infrared spectroscopy and X-ray diffraction analysis revealed hydrogen bonding in coheated samples and enhanced V-complex formation with high-pressure homogenization. The in vitro-digested complexes were of the B + V type, with higher relative crystallinity and short-range ordering of HCS-CA-HPH. Fermentation of the digested complex with human feces increased the yield of acetate, butyrate, and total short-chain fatty acids (SCFAs), which was more pronounced for HCS-CA-HPH. HCS-CA increased torques-Ruminococcaceae abundance, while HCS-CA-HPH boosted Prevotella, Roseburia, Lachnospiraceae, and Lachnospiraceae-NK4A136. Overall, CA and CS complexes enhanced beneficial bacteria and increased SCFA production.

Diet shapes and maintains the personalized native gut microbiomes in mice

BACKGROUND

The gut microbiome plays a critical role in human health and disease. Different dietary backgrounds play an important role in the uniqueness and diversity of the gut microbiota in different individuals, which promotes heterogeneity in disease phenotypes and treatment responses. Here, we explored how diet affects the composition and function of the native gut microbiome of model mice, based on the shotgun metagenomic and metabolomic, by analyzing the gut microbiome of C57B/6J mice in different dietary backgrounds.

RESULTS

The gut microbiomes of mice receiving different diets consistently exhibit distinct compositions across bacterial species, strains, fungi and phages. This implies that native microbial communities cannot 'homogenize' rapidly becaise of priority effects and unchanging diets. Notably, hotspot bacteria such as Limosilactobacillus reuteri, Parabacteroides distasonis and Akkermansia muciniphila were significantly different among the groups. These species harbor diverse adaptive mutations, reflecting genomic evolutionary diversity. The functional profiles of the gut microbiota also exhibit selective differences, involving the capacity for carbohydrate, branched-chain amino acid and fatty acid synthesis, as well as virulence factors, carbohydrate-active enzymes and antibiotic resistance. Furthermore, the differences in the gut microbiota also propagate to the host's serum, where structural and specific metabolite differences were observed. Metabolites that directly impact host health, such as d-glucosamine 6-phosphate and testolic acid, also show significant differences between the different dietary groups.

CONCLUSION

Our findings underscore the profound influence of different dietary the composition and functionality of the gut microbiome, offering valuable insights into optimizing health outcomes through personalized nutritional interventions. © 2024 Society of Chemical Industry.

Compound Probiotics Improve Neuropathic Pain Prognosis in a Murine Model of Chronic Constriction Injury

Purpose

Compound probiotics have been reported to ameliorate imbalances in the intestinal flora that may play a critical role in neuropathic pain. This study aimed to investigate the efficacy of compound probiotic treatment on neuropathic pain.

Methods

Thirty mice were randomly divided into three groups: 1) sham group, 2) mouse with chronic constrictive injury (CCI), and 3) probiotic gavage with CCI (CCI+Prob). The degree of pain and gait recovery was assessed by Mechanical withdrawal threshold (MWT), thermal withdrawal latency (TWL), and mouse footprints. The degree of atrophy of the gastrocnemius muscle was assessed by muscle weight, hematoxylin and eosin (H&E) staining. Gut microbiota were analyzed by 16S ribosomal RNA sequencing (16SrRNA).

Results

Four weeks after surgery, TWL and MWT assessment showed significant increases in the CCI+Prob group compared with the CCI group (P < 0.01). Gait analysis results as well as gastrocnemius muscle weight showed a significant improvement in the CCI+Prob group compared with the CCI group. Measurement of alpha diversity showed a significant increase in the CCI group compared with the sham group, but this increase was attenuated by probiotic intervention in the CCI+Prob group. Although the CCI group had significantly decreased levels of Akkermansia and significantly increased levels of Ruminococcaceae, probiotic treatment reversed these changes.

Conclusion

Compound probiotics treatment can improve the pain and muscle atrophy in mice with CCI-induced neuropathic pain. The improvement of symptoms is associated with changes in the composition of gut microbiota.

Antibiotic-perturbed microbiota and the role of probiotics

The disruptive effect of antibiotics on the composition and function of the human microbiota is well established. However, the hypothesis that probiotics can help restore the antibiotic-disrupted microbiota has been advanced, with little consideration of the strength of evidence supporting it. Some clinical data suggest that probiotics can reduce antibiotic-related side effects, including Clostridioides difficile-associated diarrhoea, but there are no data that causally link these clinical effects to microbiota protection or recovery. Substantial challenges hinder attempts to address this hypothesis, including the absence of consensus on the composition of a 'normal' microbiota, non-standardized and evolving microbiome measurement methods, and substantial inter-individual microbiota variation. In this Review, we explore these complexities. First, we review the known benefits and risks of antibiotics, the effect of antibiotics on the human microbiota, the resilience and adaptability of the microbiota, and how microbiota restoration might be defined and measured. Subsequently, we explore the evidence for the efficacy of probiotics in preventing disruption or aiding microbiota recovery post-antibiotic treatment. Finally, we offer insights into the current state of research and suggest directions for future research.

Stable isotope fingerprinting can directly link intestinal microorganisms with their carbon source and captures diet-induced substrate switching in vivo

Diet has strong impacts on the composition and function of the gut microbiota with implications for host health. Therefore, it is critical to identify the dietary components that support growth of specific microorganisms in vivo. We used protein-based stable isotope fingerprinting (Protein-SIF) to link microbial species in gut microbiota to their carbon sources by measuring each microbe's natural 13C content (δ13C) and matching it to the 13C content of available substrates. We fed gnotobiotic mice, inoculated with a 13 member microbiota, diets in which the 13C content of all components was known. We varied the source of protein, fiber or fat to observe 13C signature changes in microbial consumers of these substrates. We observed significant changes in the δ13C values and abundances of specific microbiota species, as well as host proteins, in response to changes in 13C signature or type of protein, fiber, and fat sources. Using this approach we were able to show that upon switching dietary source of protein, fiber, or fat (1) some microbial species continued to obtain their carbon from the same dietary component (e.g., protein); (2) some species switched their main substrate type (e.g., from protein to carbohydrates); and (3) some species might derive their carbon through foraging on host compounds. Our results demonstrate that Protein-SIF can be used to identify the dietary-derived substrates assimilated into proteins by microbes in the intestinal tract; this approach holds promise for the analysis of microbiome substrate usage in humans without the need of substrate labeling.

Significance

The gut microbiota plays a critical role in the health of animals including humans, influencing metabolism, the immune system, and even behavior. Diet is one of the most significant factors in determining the function and composition of the gut microbiota, but our understanding of how specific dietary components directly impact individual microbes remains limited. We present the application of an approach that measures the carbon isotope "fingerprint" of proteins in biological samples. This fingerprint is similar to the fingerprint of the substrate used to make the proteins. We describe how we used this approach in mice to determine which dietary components specific intestinal microbes use as carbon sources to make their proteins. This approach can directly identify components of an animal's diet that are consumed by gut microbes.

Plant-Based Diet and Sports Performance

Recently, interest in plant-based diets has grown significantly, driven by health and environmental concerns. Plant-based diets offer potential health benefits, including decreased risk of cardiovascular disease, weight management, and blood glucose regulation. This diet profile is rich in complex carbohydrates, antioxidants, dietary fiber, and phytochemicals. However, antinutrients in some plant foods can make nutrient absorption difficult, necessitating careful dietary planning. Plant-based diets can also improve sports performance; in addition, they can positively influence the intestinal microbial community, which can promote health and performance. The present study covered a review from 1986 to 2024 and involved an experimental design with human participants. The main objective was to evaluate the impact of plant-based diets on sports performance. Recent research suggests that plant-based diets do not harm athletic performance and may positively impact sports performance by improving blood flow and reducing oxidative stress. These findings have potential clinical significance, particularly for athletes seeking to optimize their physical capabilities through dietary interventions.

Nutritional management and autism spectrum disorder: A systematic review

BACKGROUND

Autism spectrum disorder (ASD) presents unique challenges related to feeding and nutritional management. Children with ASD often experience feeding difficulties, including food selectivity, refusal, and gastrointestinal issues. Various interventions have been explored to address these challenges, including dietary modifications, vitamin supplementation, feeding therapy, and behavioral interventions.

AIM

To provide a comprehensive overview of the current evidence on nutritional management in ASD. We examine the effectiveness of dietary interventions, vitamin supplements, feeding therapy, behavioral interventions, and mealtime practices in addressing the feeding challenges and nutritional needs of children with ASD.

METHODS

We systematically searched relevant literature up to June 2024, using databases such as PubMed, PsycINFO, and Scopus. Studies were included if they investigated dietary interventions, nutritional supplements, or behavioral strategies to improve feeding behaviors in children with ASD. We assessed the quality of the studies and synthesized findings on the impact of various interventions on feeding difficulties and nutritional outcomes. Data extraction focused on intervention types, study designs, participant characteristics, outcomes measured, and intervention effectiveness.

RESULTS

The review identified 316 studies that met the inclusion criteria. The evidence indicates that while dietary interventions and nutritional supplements may offer benefits in managing specific symptoms or deficiencies, the effectiveness of these approaches varies. Feeding therapy and behavioral interventions, including gradual exposure and positive reinforcement, promise to improve food acceptance and mealtime behaviors. The findings also highlight the importance of creating supportive mealtime environments tailored to the sensory and behavioral needs of children with ASD.

CONCLUSION

Nutritional management for children with ASD requires a multifaceted approach that includes dietary modifications, supplementation, feeding therapy, and behavioral strategies. The review underscores the need for personalized interventions and further research to refine treatment protocols and improve outcomes. Collaborative efforts among healthcare providers, educators, and families are essential to optimize this population's nutritional health and feeding practices. Enhancing our understanding of intervention sustainability and long-term outcomes is essential for optimizing care and improving the quality of life for children with ASD and their families.

Nutraceutical tablets: Manufacturing processes, quality assurance, and effects on human health

Consumers are increasingly focused on food products' nutritional content and health aspects. Nutraceutical tablets containing nutritional supplements have seen remarkable progress and are well-known for their precise dosage, which can improve consumer health by increasing the intake of bioactive compounds and vital nutrients. Oral nutraceuticals are frequently used to enhance consumer well-being, with around 80% of products being in solid form. This manuscript aims to thoroughly analyze and summarize the gathered literature using various search engines to investigate key trends in the market, the components involved, and the functional impact of nutraceutical tablets. Furthermore, the manuscript explores various nutraceutical tablets such as chewable tablets, gelling capsules, vitamin tablets, spirulina tablets, and bran tablets. A perspective is provided on multiple production and manufacturing methods of nutraceutical tablets, along with comparing these processes. Following this, evaluating quality characteristics and enforcing quality assurance procedures have been emphasized. The manuscript discussed the physiological breakdown of ingestible nutraceutical tablets in the human body and the possible toxic effects of the components found in these tablets. Furthermore, the focus is on producing nutraceutical tablets in a more environmentally friendly manner, tackling sustainability issues, offering solutions, and delving into potential opportunities. This manuscript will create a significant platform for people from the research, scientific, and industrial fields seeking novel and inventive projects.

The Interactions Between Diet and Gut Microbiota in Preventing Gestational Diabetes Mellitus: A Narrative Review

Recent studies have revealed that dysbiosis, defined as alterations in gut microbiota, plays an important role in the development and the progression of many non-communicable diseases, including metabolic disorders, such as type 2 diabetes mellitus and gestational diabetes mellitus (GDM). The high frequency of GDM makes this disorder an important public health issue, which needs to be addressed in order to reduce both the maternal and fetal complications that are frequently associated with this disease. The studies regarding the connections between gut dysbiosis and GDM are still in their early days, with new research continuously emerging. This narrative review seeks to outline the mechanisms through which a healthy diet that protects the gut microbiota is able to prevent the occurrence of GDM, thus providing medical nutritional therapeutic perspectives for the management of GDM.

Probiotics: a promising intervention for osteoporosis prevention and management

Osteoporosis (OP) is a systemic skeletal disease that is characterized by low bone mass and increased fracture risk. This article explores the potential of probiotics as an adjunctive approach for the prevention and management of OP. It has been well established that the gut microbiota (GM), a complex community of microbes, plays an important role in bone health. The gut dysbiosis is linked with a higher risk of OP. However, the consumption of probiotics in adequate amounts restores gut health thus improving bone health. Probiotics may influence bone metabolism through enhanced calcium absorption, reduced inflammation, and increased bone formation. The animal and human studies demonstrate the positive effects of probiotics on bone health parameters like reduced osteoclastogenesis, bone resorption markers, osteoblast, osteocyte apoptosis, and increased bone mineral density and expression of osteoprotegerin. The current evidence suggests that probiotics can be used as an adjunctive approach along with the existing therapies for the prevention and management of OP.

Back to Roots: Dysbiosis, Obesity, Metabolic Syndrome, Type 2 Diabetes Mellitus, and Obstructive Sleep Apnea-Is There an Objective Connection? A Narrative Review

In recent decades, it has become clear that the gut is more than just a digestive organ; it also functions as an immune organ with regulatory capabilities and acts as a "second brain" that influences brain function due to the presence and regulatory roles of the gut microbiota (GM). The GM is a crucial component of its host and significantly impacts human health. Dysbiosis, or microbial imbalance, has been closely linked to various diseases, including gastrointestinal, neurological, psychiatric, and metabolic disorders. The aim of this narrative review is to highlight the roles of the GM in maintaining metabolic health. Sleep is a vital biological necessity, with living organisms having evolved an internal sleep-wake rhythm that aligns with a roughly 24 h light/dark cycle, and this is known as the circadian rhythm. This cycle is essential for tissue repair, restoration, and overall optimal body functioning. Sleep irregularities have become more prevalent in modern society, with fast-paced lifestyles often disrupting normal sleep patterns. Urban living factors, such as fast food consumption, shift work, exposure to artificial light and nighttime noise, medications, and social activities, can adversely affect circadian rhythms, with dysbiosis being one of the many factors incriminated in the etiology of sleep disorders.

Gut Microbiota and Derived Metabolites Mediate Obstructive Sleep Apnea Induced Atherosclerosis

Background

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxia/hypercapnia (IHC), affects predominantly obese individuals, and increases atherosclerosis risk. Since we and others have implicated gut microbiota and metabolites in atherogenesis, we dissected their contributions to OSA-induced atherosclerosis.

Results

Atherosclerotic lesions were compared between conventionally-reared specific pathogen free (SPF) and germ-free (GF) ApoE -/- mice following a high fat high cholesterol diet (HFHC), with and without IHC conditions. The fecal microbiota and metabolome were profiled using 16S rRNA gene amplicon sequencing and untargeted tandem mass spectrometry (LC-MS/MS) respectively. Phenotypic data showed that HFHC significantly increased atherosclerosis as compared to regular chow (RC) in both aorta and pulmonary artery (PA) of SPF mice. IHC exacerbated lesions in addition to HFHC. Differential abundance analysis of gut microbiota identified an enrichment of Akkermansiaceae and a depletion of Muribaculaceae (formerly S24-7) family members in the HFHC-IHC group. LC-MS/MS showed a dysregulation of bile acid profiles with taurocholic acid, taurodeoxycholic acid, and 12-ketodeoxycholic acid enriched in the HFHC-IHC group, long-chain N-acyl amides, and phosphatidylcholines. Interestingly, GF ApoE -/- mice markedly reduced atherosclerotic formation relative to SPF ApoE -/- mice in the aorta under HFHC/IHC conditions. In contrast, microbial colonization did not show a significant impact on the atherosclerotic progression in PA.

Conclusions

In summary, this research demonstrated that (1) IHC acts cooperatively with HFHC to induce atherosclerosis; (2) gut microbiota modulate atherogenesis, induced by HFHC/IHC, in the aorta not in PA; (3) different analytical methods suggest that a specific imbalance between Akkermansiaceae and Muribaculaceae bacterial families mediate OSA-induced atherosclerosis; and (4) derived bile acids, such as deoxycholic acid and lithocholic acid, regulate atherosclerosis in OSA. The knowledge obtained provides novel insights into the potential therapeutic approaches to prevent and treat OSA-induced atherosclerosis.

Oat β-(1 → 3, 1 → 4)-d-glucan alleviates food allergy-induced colonic injury in mice by increasing Lachnospiraceae abundance and butyrate production

Oat β-(1 → 3, 1 → 4)-d-glucan (OBG), a linear polysaccharide primarily found in oat bran, has been demonstrated to possess immunomodulatory properties and regulate gut microbiota. This study aimed to investigate the impact of low molecular weight (Mw) OBG (155.2 kDa) on colonic injury and allergic symptoms induced by food allergy (FA), and to explore its potential mechanism. In Experiment 1, results indicated that oral OBG improved colonic inflammation and epithelial barrier, and significantly relieved allergy symptoms. Importantly, the OBG supplement altered the gut microbiota composition, particularly increasing the abundance of Lachnospiraceae and its genera, and promoted the production of short-chain fatty acids, especially butyrate. However, in Experiment 2, the gut microbial depletion eliminated these protective effects of OBG on the colon in allergic mice. Further, in Experiment 3, fecal microbiota transplantation and sterile fecal filtrate transfer directly validated the role of OBG-mediated gut microbiota and its metabolites in relieving FA and its induced colonic injury. Our findings suggest that low Mw OBG can alleviate FA-induced colonic damage by increasing Lachnospiraceae abundance and butyrate production, and provide novel insights into the health benefits and mechanisms of dietary polysaccharide intervention for FA.

Roseburia intestinalis: A possible target for vascular calcification

With the advancement of metagenomics and metabolomics techniques, the crucial role of the gut microbiome in intestinal, cardiovascular, and metabolic disorders has been extensively explored. Vascular calcification (VC) is common in atherosclerosis, hypertension, diabetes mellitus, and chronic kidney disease. Moreover, it is a significant cause of cardiovascular diseases and mortality. Roseburia intestinalis, as a promising candidate for the next generation of probiotics, plays a substantial role in inhibiting the systemic inflammatory response and holds great potential in the treatment of intestinal diseases, cardiovascular diseases, and metabolic disorders. Its primary metabolite, butyrate, acts on specific receptors (GPR43, GPR41, GPR109a). It enters cells via transporters (MCT1, SMCT1), affecting gene expression through HDACs, PPARγ and Nrf2, promoting energy metabolism and changing the concentration of other metabolites (including AGEs, LPS, BHB) in the circulation to affect the body's life activities. In this paper, we focus on the possible mechanism of the primary metabolite butyrate of Roseburia intestinalis in inhibiting VC, which may become a potential therapeutic target for the treatment of VC and the ways to enhance its effect.

Association between dietary inflammatory index and adolescent myopia based on the National Health and Nutrition Examination Survey

The prevalence of adolescent myopia is remarkably increasing. Previous studies have indicated that an unhealthy diet is a risk factor for myopia. However, the link between diet-related inflammation and myopia is unclear. To explore their correlation, we used dietary inflammation index (DII) that is a parameter to quantify the inflammatory potential of diet, to reveal the relationship between DII and myopia in adolescents. We extracted sociodemographic data, information of diets and eye refractive status of adolescents from National Health and Nutrition Examination Survey (NHANES) for period 1999-2008. Dietary intake data was used to calculate DII scores, which were then categorized into quartiles. Multivariable regression models and subgroup analyses were conducted to investigate the association between DII and myopia. Subsequently, smoothed curve analyses were conducted to discern the trend of correlation between DII and myopia across diverse population. A total of 7191 juveniles aged at 12 to 18 years with complete information were included in our study, consisting 3367 participants with diagnosis of myopia. Among these participants, a trend towards an increasing prevalence of myopia was observed with a higher DII. After adjusting for all covariates, stratified logistic regression analyses showed that among the population aged in 16 to 18 years old or with 9-11th grade educational level, the prevalence of myopia was significantly increased with higher DII score (OR = 1.06, 95% CI = 1.01, 1.11, P = 0.006; OR = 1.06, 95% CI = 1.01, 1.11, P = 0.010). In the two subgroups, participants in the highest quartile of DII had a 31.00% higher risk of myopia and a higher 27.00% risk of myopia respectively, compared to those in the lowest quartile of DII. Our results revealed an increasing trend in the prevalence of myopia with increased DII score in adolescents. Particularly, DII was positively associated with the risk of myopia among the population aged in 16 to 18 years old and with 9-11th grade educational level.

Gut Microbiota and Liver Regeneration: A Synthesis of Evidence on Structural Changes and Physiological Mechanisms

Liver regeneration (LR) is a unique biological process with the ability to restore up to 70% of the organ. This allows for the preservation of liver resections for various liver tumors and for living donor liver transplantation (LDLT). However, in some cases, LR is insufficient and interventions that can improve LR are urgently needed. Gut microbiota (GM) is one of the factors influencing LR, as the liver and intestine are intimately connected through the gut-liver axis. Thus, healthy GM facilitates normal LR, whereas dysbiosis leads to impaired LR due to imbalance of bile acids, inflammatory cytokines, microbial metabolites, signaling pathways, etc. Therefore, GM can be considered as a new possible therapeutic target to improve LR. In this review, we critically observe the current knowledge about the influence of gut microbiota (GM) on liver regeneration (LR) and the possibility to improve this process, which may reduce complication and mortality rates after liver surgery. Although much research has been done on this topic, more clinical trials and systemic reviews are urgently needed to move this type of intervention from the experimental phase to the clinical field.

The Association between Gut Microbiota and Its Metabolites in Gestational Diabetes Mellitus

Gut microbial metabolites have been demonstrated to play a role in diabetes mellitus and gestational diabetes mellitus (GDM). This study aimed to investigate gut microbiome, fecal metabolomics, and their association in pregnant women with and without GDM. The metabolome indicated that the top 2 differential metabolic pathways between control (Con) and GDM groups were phenylalanine metabolism and nucleotide metabolism. The increased Phenylalanylglycine, m-coumaric acid, and Phenylacetic acid were among the top differential metabolites between Con and GDM groups and involved in phenylalanine metabolism. Uracil and hypoxanthine were top differential metabolites in Con vs. GDM and involved in nucleotide metabolism. The proficiently altered gut microbiota at the class level was c_unclassified_ Firmicutes. Association analysis between gut microbiota and fecal metabolites indicated that the increased gut symbiont Clostridium belonged to Firmicutes and was linked to the dysregulation of phenylalanine metabolism in GDM. This study may provide the mechanism underlying how Clostridium-phenylalanine metabolism association contributes to GDM pathogenesis and also be a novel therapeutic strategy to treat GDM.

Rosmarinic Acid Attenuates Salmonella enteritidis-Induced Inflammation via Regulating TLR9/NF-κB Signaling Pathway and Intestinal Microbiota

Salmonella enteritidis (SE) infection disrupts the homeostasis of the intestinal microbiota, causing an intestinal inflammatory response and posing a great threat to human and animal health. The unreasonable use of antibiotics has led to an increase in the prevalence of drug-resistant SE, increasing the difficulty of controlling SE. Therefore, new drug strategies and research are urgently needed to control SE. Rosmarinic acid (RA) is a natural phenolic acid with various pharmacological activities, including antioxidant, anti-inflammatory and antibacterial properties. However, the protective effects and mechanism of RA on intestinal inflammation and the gut microbial disorders caused by SE have not been fully elucidated. In this study, RAW264.7 cells, MCECs and BALB/c mice were challenged with SE to assess the protective effects and mechanisms of RA. The results showed that RA enhanced the phagocytic ability of RAW264.7 cells, reduced the invasion and adhesion ability of SE in MCECs, and inhibited SE-induced inflammation in cells. Moreover, RA inhibited the activation of the NF-κB signaling pathway by upregulating TLR9 expression. Importantly, we found that RA provided protection against SE and increased the diversity and abundance of the intestinal microbiota in mice. Compared with infection control, RA significantly increased the abundance of Firmicutes and Acidibacteria and decreased the abundance of Proteobacteria, Epsilonbacteraeota and Bacteroidota. However, RA failed to alleviate SE-induced inflammation and lost its regulatory effects on the TLR9/NF-κB signaling pathway after destroying the gut microbiota with broad-spectrum antibiotics. These results indicated that RA attenuated SE-induced inflammation by regulating the TLR9/NF-κB signaling pathway and maintaining the homeostasis of the gut microbiota. Our study provides a new strategy for preventing SE-induced intestinal inflammation.

Akkermansia muciniphila: biology, microbial ecology, host interactions and therapeutic potential

Akkermansia muciniphila is a gut bacterium that colonizes the gut mucosa, has a role in maintaining gut health and shows promise for potential therapeutic applications. The discovery of A. muciniphila as an important member of our gut microbiome, occupying an extraordinary niche in the human gut, has led to new hypotheses on gut health, beneficial microorganisms and host-microbiota interactions. This microorganism has established a unique position in human microbiome research, similar to its role in the gut ecosystem. Its unique traits in using mucin sugars and mechanisms of action that can modify host health have made A. muciniphila a subject of enormous attention from multiple research fields. A. muciniphila is becoming a model organism studied for its ability to modulate human health and gut microbiome structure, leading to commercial products, a genetic model and possible probiotic formulations. This Review provides an overview of A. muciniphila and Akkermansia genus phylogeny, ecophysiology and diversity. Furthermore, the Review discusses perspectives on ecology, strategies for harnessing beneficial effects of A. muciniphila for human mucosal metabolic and gut health, and its potential as a biomarker for diagnostics and prognostics.

Dietary Polyphenols, Food Processing and Gut Microbiome: Recent Findings on Bioavailability, Bioactivity, and Gut Microbiome Interplay

Polyphenols are organic chemical compounds naturally present in plants, renowned for their anti-inflammatory, antioxidant, immunomodulatory, anticancer, and cardiovascular protective properties. Their bioactivity and bioavailability can vary widely depending on the methods of food processing and interactions with the gut microbiome. These factors can induce changes in polyphenols, affecting their ability to achieve their intended health benefits. Thus, it is essential to develop and apply food processing methods that optimize polyphenol content while maintaining their bioactivity and bioavailability. This review aims to explore how various food processing techniques affect the quantity, bioactivity, and bioavailability of polyphenols, as well as their interactions with the gut microbiome, which may ultimately determine their health effects.

Proton Pump Inhibitors and Oral-Gut Microbiota: From Mechanism to Clinical Significance

Proton pump inhibitors (PPIs) are some of the most commonly prescribed drugs worldwide, but there are increasing concerns about digestive complications linked to PPIs. Next-generation sequencing studies have suggested that PPIs can significantly affect the composition of the gut microbiota, which in turn may substantially contribute to the development of these complications. Recently, emerging evidence has suggested that the translocation of oral microbes into the gut may be the primary mechanism underlying the alterations in the gut microbiota induced by PPIs in the presence of gastric acid suppression and impaired oral-gut barrier function. Moreover, the significance of oral-gut microbial translocation in health and disease conditions has gained increasing recognition. Consequently, it is imperative to enhance our understanding of the functions of the oral-gut microbiota axis in digestive disorders associated with PPI therapies. This review aims to summarize current research findings and further elucidate the contribution of the oral-gut microbiota to the pathogenesis of PPI-related digestive diseases. We aim to provide a theoretical foundation for future therapeutic and preventive strategies targeting PPI-related digestive complications through modulation of the oral-gut microbiota.

Impact of Food Intake and Sleep Disturbances on Gut Microbiota

Lactobacilli and Bifidobacteria are types of microbiota that live in the gastrointestinal (GI) system, or gut microbiota, and are essential for both human well-being and disease. This review looks at the relationship between the composition of gut microbiota and function and two important lifestyle factors - dietary intake and sleep disorders. The diversity of the gut microbiota and metabolic processes is strongly influenced by food intake. Fiber-rich diets encourage the development of good bacteria that synthesize short-chain fatty acids (SCFA), while diets heavy in fat or sugar can negatively impact the microbial balance. Microbial communities are also impacted by regular meal schedules and probiotic and prebiotic use. Sleep disturbances cause stress reactions that alter gut microbiota and upset circadian rhythms. These include irregular sleep cycles and insomnia. These effects are driven by the immune system and gut-brain axis dysregulation, which affects microbial diversity and plays a role in GI and metabolic illnesses. The significance of comprehensive lifestyle treatments to improve gut health is highlighted by an understanding of these interconnections. It may be possible to modify the composition of gut microbiota and improve general health outcomes through the use of strategies that emphasize balanced meals, consistent eating schedules, and better sleep hygiene.

The interaction of polyphenols-polysaccharides and their applications: A review

Polyphenols, as important secondary metabolites in nature, are widely distributed in vegetables, fruits, grains, and other foods. Polyphenols have attracted widespread attention in the food industry and nutrition due to their unique structure and various biological activities. However, the health benefits of polyphenols are compromised owing to their structural instability and sensitivity to the external environment. The interaction between polyphenols and polysaccharides largely determined the stability and functional characteristics of polyphenols in food processing and storage. Thus, this topic has attracted widespread attention in recent years. The main purposes of this article are as follows: 1) to review the interaction mechanisms of polyphenols and polysaccharides including non-covalent and covalent bonds; 2) to comprehensively analyze the influencing factors of the interaction between polyphenols and polysaccharides, and introduce the effects of their interaction on the properties of polyphenols; 3) to systematically summarize the applications of interaction between polyphenols and polysaccharides. The findings can provide the important reference and theoretical support for the application of polyphenols and polysaccharides in food industry.

Therapeutic potential of the ketogenic diet: A metabolic switch with implications for neurological disorders, the gut-brain axis, and cardiovascular diseases

The Ketogenic Diet (KD) is a dietary regimen that is low in carbohydrates, high in fats, and contains adequate protein. It is designed to mimic the metabolic state of fasting. This diet triggers the production of ketone bodies through a process known as ketosis. The primary objective of KD is to induce and sustain ketosis, which has been associated with numerous health benefits. Recent research has uncovered promising therapeutic potential for KD in the treatment of various diseases. This includes evidence of its effectiveness as a dietary strategy for managing intractable epilepsy, a form of epilepsy that is resistant to medication. We are currently assessing the efficacy and safety of KD through laboratory and clinical studies. This review focuses on the anti-inflammatory properties of the KD and its potential benefits for neurological disorders and the gut-brain axis. We also explore the existing literature on the potential effects of KD on cardiac health. Our aim is to provide a comprehensive overview of the current knowledge in these areas. Given the encouraging preliminary evidence of its therapeutic effects and the growing understanding of its mechanisms of action, randomized controlled trials are warranted to further explore the rationale behind the clinical use of KD. These trials will ultimately enhance our understanding of how KD functions and its potential benefits for various health conditions. We hope that our research will contribute to the body of knowledge in this field and provide valuable insights for future studies.

MicroHDF: predicting host phenotypes with metagenomic data using a deep forest-based framework

The gut microbiota plays a vital role in human health, and significant effort has been made to predict human phenotypes, especially diseases, with the microbiota as a promising indicator or predictor with machine learning (ML) methods. However, the accuracy is impacted by a lot of factors when predicting host phenotypes with the metagenomic data, e.g. small sample size, class imbalance, high-dimensional features, etc. To address these challenges, we propose MicroHDF, an interpretable deep learning framework to predict host phenotypes, where a cascade layers of deep forest units is designed for handling sample class imbalance and high dimensional features. The experimental results show that the performance of MicroHDF is competitive with that of existing state-of-the-art methods on 13 publicly available datasets of six different diseases. In particular, it performs best with the area under the receiver operating characteristic curve of 0.9182 ± 0.0098 and 0.9469 ± 0.0076 for inflammatory bowel disease (IBD) and liver cirrhosis, respectively. Our MicroHDF also shows better performance and robustness in cross-study validation. Furthermore, MicroHDF is applied to two high-risk diseases, IBD and autism spectrum disorder, as case studies to identify potential biomarkers. In conclusion, our method provides an effective and reliable prediction of the host phenotype and discovers informative features with biological insights.

Substitutive Effects of Milk vs. Vegetable Milk on the Human Gut Microbiota and Implications for Human Health

Background: In the last two decades, the consumption of plant-based dairy substitutes in place of animal-based milk has increased in different geographic regions of the world. Dairy substitutes of vegetable origin have a quantitative composition of macronutrients such as animal milk, although the composition of carbohydrates, proteins and fats, as well as bioactive components, is completely different from that of animal milk. Many milk components have been shown to have relevant effects on the intestinal microbiota. Methods: Therefore, the aim of this review is to compare the effects obtained by previous works on the composition of the gut microbiota after the ingestion of animal milk and/or vegetable beverages. Results: In general, the results obtained in the included studies were very positive for animal milk intake. Thus, we found an increase in gut microbiota richness and diversity, increase in the production of short-chain fatty acids, and beneficial microbes such as Bifidobacterium, lactobacilli, Akkermansia, Lachnospiraceae or Blautia. In other cases, we found a significant decrease in potential harmful bacteria such as Proteobacteria, Erysipelotrichaceae, Desulfovibrionaceae or Clostridium perfingens after animal-origin milk intake. Vegetable beverages have also generally produced positive results in the gut microbiota such as the increase in the relative presence of lactobacilli, Bifidobacterium or Blautia. However, we also found some potential negative results, such as increases in the presence of potential pathogens such as Enterobacteriaceae, Salmonella and Fusobacterium. Conclusions: From the perspective of their effects on the intestinal microbiota, milks of animal origin appear to be more beneficial for human health than their vegetable substitutes. These different effects on the intestinal microbiota should be considered in those cases where the replacement of animal milks by vegetable substitutes is recommended.

Identification of dietary factors that impact the gut microbiota associated with vitiligo: A Mendelian randomization study and meta-analysis

Previous observational studies have suggested that gut microbiota might be associated with vitiligo. However, owing to the limitations in observational studies of reverse causality and confounders, it remains unclear that whether and how the causal relationships exist. The results suggested that pylum.Bacteroidetes, family.BacteroidalesS24.7, genus.LachnospiraceaeND3007, genus.Marvinbryantia are protective factors for vitiligo. Conversely, family.Lachnospiraceae, order.Burkholderiales, genus.Adlercreutzia, genus.Catenibacterium and genus.Lachnospira are risk factors for vitiligo. In addition, the causative connection between dietary factors and the gut microbiota associated with vitiligo was also investigated. The results revealed that 'alcohol intake versus 10 years pervious' results in a reduction in the abundance of genus.Lachnospiraceae ND3007 and family.BacteroidalesS24.7, bread intake leads to a reduction of genus.Marvinbryantia, 'average weekly red wine intake' is linked to a decrease in the abundance of order.Burkholderiales, tea intake is associated with an augmentation in the abundance of genus.Catenibacterium, salad/raw vegetable intake elevates the abundance of order.Burkholderiales. In summary, this Mendelian randomization study substantiates potential causal effects of gut microbiota on vitiligo. Modulating the gut microbiota through regulating dietary composition may be a novel strategy for preventing vitiligo.

Potential Trimethylamine (TMA)-Producing Bacteria in patients with chronic kidney disease undergoing hemodialysis

INTRODUCTION

Trimethylamine (TMA), produced by gut microbiota, is the precursor of trimethylamine-N-oxide (TMAO), a uremic toxin that accumulates in patients with chronic kidney disease (CKD). Elevated TMAO plasma levels are associated with cardiovascular complications and CKD progression.

OBJECTIVE

To evaluate the association between gut microbiota composition and TMAO plasma levels in CKD patients undergoing hemodialysis (HD).

METHODS

This is a cross-sectional study with 25 patients evaluated (60% female, 53 (18) years, body mass index (BMI) 25.8 (6.75) Kg/m2). They were divided into two groups according to their TMAO plasma levels: normal (≤ 7.4 μM) and high (> 7.4 μM). Uremic toxins such as indoxyl sulfate (IS), p-cresyl sulfate (pCS), and indol acetic acid (IAA) were measured with RP-HPLC, and TMAO plasma levels were quantified using LC-MS/MS. Fecal DNA was extracted with a commercial kit, PCR amplified the V4 region of the 16S rRNA gene, and short-read sequencing was performed on the Illumina platform. Dietary intake, anthropometric measurements, and inflammation markers were also evaluated. Nrf2, NF-κB, IL-1β, and NLRP3 mRNA expressions were measured from peripheral blood mononuclear cells (PBMC) using quantitative real-time polymerase chain reaction (qPCR).

RESULTS

There were significant positive correlations between TMAO and plasma levels of pCS, NLPR3 inflammasome mRNA expression, serum phosphorus levels, and negative correlations with dietary lipid intake. The group with TMAO > 7.4 μM showed an increase in the microbiome abundance of Saccharibacteria (genus incertae sedis), Colidextribacter, Dorea, and Staphylococci genera, and a decrease in abundance in the genera Lachnospira, Lactobacilli, and Victivallis. TMAO plasma level was positively correlated with the abundance of bacteria of the genera Colidextribacter and Helicobacter and was negatively correlated with Sphingomanos, Lachnospira, Streptomyces, and Bacillus genera.

CONCLUSION

Saccharibacteria (genus incertae sedis), Colidextribacter, Dorea, and Staphylococci genera showed higher abundance in patients with high TMAO levels. In addition, we observed that elevated plasma TMAO levels are associated with inflammation markers, dietary lipid intake, and serum phosphorus levels in patients undergoing HD.

High-Salt Diet and Intestinal Microbiota: Influence on Cardiovascular Disease and Inflammatory Bowel Disease

Salt, or sodium chloride, is an essential component of the human diet. Recent studies have demonstrated that dietary patterns characterized by a high intake of salt can influence the abundance and diversity of the gut microbiota, and may play a pivotal role in the etiology and exacerbation of certain diseases, including inflammatory bowel disease and cardiovascular disease. The objective of this review is to synthesize the effects of elevated salt consumption on the gut microbiota, including its influence on gut microbial metabolites and the gut immune system. Additionally, this review will investigate the potential implications of these effects for the development of cardiovascular disease and inflammatory bowel disease. The findings of this study offer novel insights and avenues for the management of two common conditions with significant clinical implications.

A Comprehensive Review of the Triangular Relationship among Diet-Gut Microbiota-Inflammation

The human gastrointestinal tract hosts a complex and dynamic community of microorganisms known as the gut microbiota, which play a pivotal role in numerous physiological processes, including digestion, metabolism, and immune function. Recent research has highlighted the significant impact of diet on the gut microbiota composition and functionality, and the consequential effects on host health. Concurrently, there is growing evidence linking the gut microbiota to inflammation, a key factor in many chronic diseases such as inflammatory bowel disease (IBD), obesity, diabetes, and cardiovascular diseases (CVDs). This review explores how dietary components influence the gut microbiota composition, how these microbial changes affect inflammatory pathways, and the therapeutic implications of modulating this axis for chronic inflammatory disease prevention and management. Beneficial dietary patterns, such as the Mediterranean diet (MD) and plant-based diets, promote a diverse and balanced gut microbiota composition, supporting anti-inflammatory pathways. Conversely, the Western diet (WD), high in saturated fats and refined sugars, is associated with dysbiosis and increased inflammation. With all the links between the three variables considered, this review attempts to offer a thorough examination of the triangle formed by inflammation, the gut microbiota, and food.

The Impact of Japanese Dietary Patterns on Metabolic Dysfunction-Associated Steatotic Liver Disease and Liver Fibrosis

This study aimed to investigate the effect of Japanese dietary patterns on metabolic dysfunction-associated steatotic liver disease (MASLD) and liver fibrosis. After excluding factors affecting the diagnosis of hepatic steatosis, 727 adults were analyzed as part of the Health Promotion Project. The dietary patterns of the participants were classified into rice, vegetable, seafood, and sweet based on their daily food intake. Liver stiffness measurements and controlled attenuation parameters were performed using FibroScan. Energy and nutrient intake were calculated using the Brief-type Self-administered Diet History Questionnaire. Univariate and multivariate analyses were used to identify the risk factors for liver fibrosis within the MASLD population. The vegetable group had significantly lower liver fibrosis indicators in the MASLD population than the rice group. The multivariate analysis identified a body mass index ≥ 25 kg/m2 (odds ratio [OR], 1.83; 95% confidence interval [CI], 1.01-1.83; p = 0.047) and HOMA-IR ≥ 1.6 (OR, 3.18; 95% CI, 1.74-5.78; p < 0.001) as risk factors for liver fibrosis, and vegetable group membership was a significant low-risk factor (OR, 0.38; 95% CI, 0.16-0.88; p = 0.023). The multivariate analysis of nutrients in low-risk foods revealed high intake of α-tocopherol (OR, 0.74; 95% CI, 0.56-0.99; p = 0.039) as a significant low-risk factor for liver fibrosis. This study suggests that a vegetable-based Japanese dietary pattern, through the antioxidant effects of α-tocopherol, may help prevent liver fibrosis in MASLD and the development of MASLD.

The gut microbiota improves the efficacy of immune-checkpoint inhibitor immunotherapy against tumors: From association to cause and effect

Immune-checkpoint inhibitors (ICIs), including anti-PD-1/PD-L1 therapeutic antibodies, have markedly enhanced survival across numerous cancer types. However, the limited number of patients with durable benefits creates an urgent need to identify response biomarkers and to develop novel strategies so as to improve response. It is widely recognized that the gut microbiome is a key mediator in shaping immunity. Additionally, the gut microbiome shows significant potential in predicting the response to and enhancing the efficacy of ICI immunotherapy against cancer. Recent studies encompassing mechanistic analyses and clinical trials of microbiome-based therapy have shown a cause-and-effect relationship between the gut microbiome and the modulation of the ICI immunotherapeutic response, greatly contributing to the establishment of novel strategies that will improve response and overcome resistance to ICI treatment. In this review, we outline the current state of research advances and discuss the future directions of utilizing the gut microbiome to enhance the efficacy of ICI immunotherapy against tumors.

Interactions between Gut Microbiota and Natural Bioactive Polysaccharides in Metabolic Diseases: Review

The gut microbiota constitutes a complex ecosystem, comprising trillions of microbes that have co-evolved with their host over hundreds of millions of years. Over the past decade, a growing body of knowledge has underscored the intricate connections among diet, gut microbiota, and human health. Bioactive polysaccharides (BPs) from natural sources like medicinal plants, seaweeds, and fungi have diverse biological functions including antioxidant, immunoregulatory, and metabolic activities. Their effects are closely tied to the gut microbiota, which metabolizes BPs into health-influencing compounds. Understanding how BPs and gut microbiota interact is critical for harnessing their potential health benefits. This review provides an overview of the human gut microbiota, focusing on its role in metabolic diseases like obesity, type II diabetes mellitus, non-alcoholic fatty liver disease, and cardiovascular diseases. It explores the basic characteristics of several BPs and their impact on gut microbiota. Given their significance for human health, we summarize the biological functions of these BPs, particularly in terms of immunoregulatory activities, blood sugar, and hypolipidemic effect, thus providing a valuable reference for understanding the potential benefits of natural BPs in treating metabolic diseases. These properties make BPs promising agents for preventing and treating metabolic diseases. The comprehensive understanding of the mechanisms by which BPs exert their effects through gut microbiota opens new avenues for developing targeted therapies to improve metabolic health.

Microbiome and Microbial Pure Culture Study Reveal Commensal Microorganisms Alleviate Salmonella enterica Serovar Pullorum Infection in Chickens

Pullorum disease, an intestinal disease in chickens caused by Salmonella enterica serovar pullorum (S. Pullorum), is a significant threat to the poultry industry and results in substantial economic losses. The bacteria's transmission, both vertical and horizontal, makes it difficult to completely eliminate it. Control strategies for pullorum disease primarily involve stringent eradication programs that cull infected birds and employ antibiotics for treatment. However, eradication programs are costly, and antibiotic use is restricted. Therefore, developing alternative control strategies is essential. Increasingly, studies are focusing on modulating the gut microbiota to control intestinal diseases. Modulating the chicken gut microbiota may offer a novel strategy for preventing and controlling pullorum disease in poultry. However, the impact of S. Pullorum on the chicken gut microbiota has not been well established, prompting our exploration of the relationship between S. Pullorum and the chicken gut microbiota in this study. In this study, we initially analyzed the dynamic distribution of the gut microbiota in chickens infected with S. Pullorum. Alpha diversity analysis revealed a decrease in observed OTUs and the Shannon diversity index in the infected group, suggesting a reduction in the richness of the chicken gut microbiota due to S. Pullorum infection. Principal coordinate analysis (PCoA) showed distinct clusters between the gut microbiota of infected and uninfected groups, indicating S. Pullorum infection changed the chicken gut microbiota structure. Specifically, S. Pullorum infection enriched the relative abundance of the genera Escherichia-Shigella (65% in infected vs. 40.6% in uninfected groups) and Enterococcus (10.8% vs. 3.7%) while reducing the abundance of Lactobacillus (9.9% vs. 32%) in the chicken microbiota. Additionally, based on the observed changes in the chicken gut microbiota, we isolated microorganisms, including Bifidobacterium pseudolongum, Streptococcus equi and Lacticaseibacillus paracasei (L. paracasei), which were decreased by S. Pullorum infection. Notably, the L. paracasei Lp02 strain was found to effectively inhibit S. Pullorum proliferation in vitro and alleviate its infection in vivo. We found that S. Pullorum infection reduced the richness of the chicken gut microbiota and enriched the relative abundance of the genera Escherichia-Shigella and Enterococcus while decreasing the abundance of the anaerobic genus Lactobacillus. Furthermore, microbiota analysis enabled the isolation of several antimicrobial microorganisms from healthy chicken feces, with a L. paracasei strain notably inhibiting S. Pullorum proliferation in vitro and alleviating its infection in vivo. Overall, this research enhances our understanding of the interaction between gut microbiota and pathogen infection, as well as offers new perspectives and strategies for modulating the chicken gut microbiota to control pullorum disease.

Two-Year Study on the Intra-Individual Dynamics of Gut Microbiota and Short-Chain Fatty Acids Profiles in Healthy Adults

While the gut microbiome has been intensively investigated for more than twenty years already, its role in various disorders remains to be unraveled. At the same time, questions about what changes in the gut microbiota can be considered as normal or pathological and whether communities are able to recover after exposure to negative factors (diseases, medications, environmental factors) are still unclear. Here, we describe changes in the gut microbiota composition and the content of short-chain fatty acids in adult healthy volunteers (n = 15) over a 24 month-period. Intraindividual variability in gut microbial composition was 40%, whereas the short chain fatty acids profile remained relatively stable (2-year variability 20%, inter-individual 26%). The changes tend to accumulate over time. Nevertheless, both short-term and long-term changes in the gut microbiome composition were significantly smaller within individuals than interindividual differences (two-year interindividual variability was 75%). Seasonal changes in gut microbiota were found more often in autumn and spring involving the content of minor representatives (less than 1.5% of the community in average) in the phyla Actinobacteriota, Firmicutes and Proteobacteria.

Polysaccharides from Trametes versicolor as a Potential Prebiotic to Improve the Gut Microbiota in High-Fat Diet Mice

Polysaccharides derived from Trametes versicolor have been found to exhibit hypolipidemic activity in hyperlipidemic mice, but the mechanism by which they modulate intestinal flora is still unclear. Currently, this study aimed to investigate the regulatory effects of extracellular (EPTV) and intracellular polysaccharides from T. versicolor (IPTV) on the dysbiosis of intestinal flora in mice fed a high-fat diet (HFD). The results showed that the oral administration of T. versicolor polysaccharides significantly ameliorated lipid accumulation and steatosis in hepatocytes. The gut dysbiosis in the HFD mice was characterized by a decrease in abundance and diversity of bacteria and an increase in the Firmicutes/Bacteroidetes ratio. However, T. versicolor polysaccharides attenuated these changes and reduced the relative abundance of bile-salt-hydrolase (BSH)-producing bacteria, such as Bacillus, Enterococcus, Bifidobacterium, and Lactococcus. It is noteworthy that T. versicolor polysaccharides also restored the disorganization of intestinal fungi in HFD mice, with EPTV treatment leading to a higher relative abundance of Basidiomycota and Ascomycota compared to IPTV. Additionally, T. versicolor polysaccharides enhanced the growth of butyrate-producing bacteria via the buk and but pathways, accompanied by an increase in short-chain fatty acids (SCFAs), especially butyrate. IPTV also increased the expression of G-protein-coupled receptors 41 (GPR41) and 43 (GPR43) by 40.52% and 113.24% each, as compared to 62.42% and 110.28%, respectively, for EPTV. It is suggested that IPTV and EPTV have the potential to counteract hyperlipidemia-associated intestinal flora disorders and improve lipid metabolism.

Mendelian randomization study reveals causal effects of specific gut microbiota on the risk of interstitial cystitis/bladder pain syndrome (IC/BPS)

Evidence from previous studies have demonstrated that gut microbiota are closely associated with occurrence of interstitial cystitis/bladder pain syndrome (IC/BPS), yet the causal link between the two is not well known. In this study, we performed a two-sample Mendelian randomization (MR) analysis to determine the possible causal association between gut microbiota with IC/BPS. Gut microbiota summary level data were derived from the genome-wide association study (GWAS) conducted by MiBioGen and the IC/BPS GWAS summary level data were obtained from the GWAS Catalog. Next, we performed an MR study to investigate the causal link between gut microbiota and IC/BPS. The primary method for causal analysis was the inverse variance weighted (IVW), and the MR results were validated through multiple sensitivity analyses. A positive association was found between IC/BPS and eight gut microbial taxa, including genus Bacteroides, genus Haemophilus, genus Veillonella, genus Coprococcus1, genus Butyricimonas, family Bacteroidaceae, family Christensenellaceae, and order Lactobacillales. Sensitivity analysis revealed lack of significant pleiotropy or heterogeneity in the obtained results. This MR analysis reveals that a causal association exists between some gut microbiota with IC/BPS. This finding may is expected to guide future research and development of IC/BPS preventions and treatments based on the bladder-gut axis. However, given the clinical complexity and diagnostic challenges of IC/BPS, along with the limitations of using large-scale GWAS summary data for analysis, our MR results require further validation through additional research.

Kidney transplantation and gut microbiota

Kidney transplantation is an effective way to improve the condition of patients with end-stage renal disease. However, maintaining long-term graft function and improving patient survival remain a key challenge after kidney transplantation. Dysbiosis of intestinal flora has been reported to be associated with complications in renal transplant recipients. The commensal microbiota plays an important role in the immunomodulation of the transplant recipient responses. However, several processes, such as the use of perioperative antibiotics and high-dose immunosuppressants in renal transplant recipients, can lead to gut dysbiosis and disrupt the interaction between the microbiota and the host immune responses, which in turn can lead to complications such as infection and rejection in organ recipients. In this review, we summarize and discuss the changes in intestinal flora and their influencing factors in patients after renal transplantation as well as the evidence related to the impact of intestinal dysbiosis on the prognosis of renal transplantation from in vivo and clinical studies, and conclude with a discussion of the use of microbial therapy in the transplant population. Hopefully, a deeper understanding of the function and composition of the microbiota in patients after renal transplantation may assist in the development of clinical strategies to restore a normal microbiota and facilitate the clinical management of grafts in the future.

The gut microbiota-brain axis in neurological disorders

Previous studies have shown a bidirectional communication between human gut microbiota and the brain, known as the microbiota-gut-brain axis (MGBA). The MGBA influences the host's nervous system development, emotional regulation, and cognitive function through neurotransmitters, immune modulation, and metabolic pathways. Factors like diet, lifestyle, genetics, and environment shape the gut microbiota composition together. Most research have explored how gut microbiota regulates host physiology and its potential in preventing and treating neurological disorders. However, the individual heterogeneity of gut microbiota, strains playing a dominant role in neurological diseases, and the interactions of these microbial metabolites with the central/peripheral nervous systems still need exploration. This review summarizes the potential role of gut microbiota in driving neurodevelopmental disorders (autism spectrum disorder and attention deficit/hyperactivity disorder), neurodegenerative diseases (Alzheimer's and Parkinson's disease), and mood disorders (anxiety and depression) in recent years and discusses the current clinical and preclinical gut microbe-based interventions, including dietary intervention, probiotics, prebiotics, and fecal microbiota transplantation. It also puts forward the current insufficient research on gut microbiota in neurological disorders and provides a framework for further research on neurological disorders.

The link between gut microbiome and Alzheimer's disease: From the perspective of new revised criteria for diagnosis and staging of Alzheimer's disease

Over the past decades, accumulating evidence suggests that the gut microbiome exerts a key role in Alzheimer's disease (AD). The Alzheimer's Association Workgroup is updating the diagnostic criteria for AD, which changed the profiles and categorization of biomarkers from "AT(N)" to "ATNIVS." Previously, most of studies focus on the correlation between the gut microbiome and amyloid beta deposition ("A"), the initial AD pathological feature triggering the "downstream" tauopathy and neurodegeneration. However, limited research investigated the interactions between the gut microbiome and other AD pathogenesis ("TNIVS"). In this review, we summarize current findings of the gut microbial characteristics in the whole spectrum of AD. Then, we describe the association of the gut microbiome with updated biomarker categories of AD pathogenesis. In addition, we outline the gut microbiome-related therapeutic strategies for AD. Finally, we discuss current key issues of the gut microbiome research in the AD field and future research directions. HIGHLIGHTS: The new revised criteria for Alzheimer's disease (AD) proposed by the Alzheimer's Association Workgroup have updated the profiles and categorization of biomarkers from "AT(N)" to "ATNIVS." The associations of the gut microbiome with updated biomarker categories of AD pathogenesis are described. Current findings of the gut microbial characteristics in the whole spectrum of AD are summarized. Therapeutic strategies for AD based on the gut microbiome are proposed.

A comprehensive review of synbiotics: an emerging paradigm in health promotion and disease management

Synbiotics are complex preparations of prebiotics that can be selectively utilized by live microorganisms to improve host health. Synbiotics are divided into complementary synbiotics, which consist of probiotics and prebiotics with independent functions, and synergistic synbiotics, which consist of prebiotics that are selectively used by gut microorganisms. Complementary synbiotics used in human clinical trials include Lactobacillus spp. and Bifidobacterium spp. as probiotics, and fructooligosaccharides, galactooligosaccharides, and inulin as prebiotics. Over the past five years, synbiotics have been most commonly used in patients with metabolic disorders, including obesity, and immune and gastrointestinal disorders. Several studies have observed alterations in the microbial community; however, these changes did not lead to significant improvements in disease outcomes or biochemical and hematological markers. The same synbiotics have been applied to individuals with different gut environments. As a result, even with the same synbiotics, there are non-responders who do not respond to the applied synbiotics due to the different intestinal environment for each individual. Therefore, to obtain meaningful results, applying different synbiotics depending on the individual is necessary. Synergistic synbiotics are one solution to circumvent this problem, as they combine elements that can effectively improve health, even in non-responders. This review aims to explain the concept of synbiotics, highlight recent human clinical trials, and explore the current state of research on synergistic synbiotics.

Combined dilute alkali and milling process enhances the functionality and gut microbiota fermentability of insoluble corn fiber

In this study, we developed a process combining dilute alkali (NaOH or NaHCO3) and physical (disk milling and/or ball milling) treatments to improve the functionality and fermentability of corn fiber. The results showed that combining chemical with physical processes greatly improved the functionality and fermentability of corn fiber. Corn fiber treated with NaOH followed by disk milling (NaOH-DM-CF) had the highest water retention (19.5 g/g), water swelling (38.8 mL/g), and oil holding (15.5 g/g) capacities. Moreover, NaOH-DM-CF produced the largest amount (42.9 mM) of short-chain fatty acid (SCFA) during the 24-hr in vitro fermentation using porcine fecal inoculum. In addition, in vitro fermentation of NaOH-DM-CF led to a targeted microbial shifting to Prevotella (genus level), aligning with a higher fraction of propionic acid. The outstanding functionality and fermentability of NaOH-DM-CF were attributed to its thin and loose structure, decreased ester linkages and acetyl groups, and enriched structural carbohydrate exposure.

Baseline gut microbiota profiles affect treatment response in patients with depression

The role of the gut microbiota in the pathophysiology of depression has been explored in numerous studies, which have confirmed that the baseline gut microbial profiles of patients with depression differ from those of healthy individuals. The gut microbiome affects metabolic activity in the immune and central nervous systems and regulates intestinal ecology through the neuroendocrine system. Additionally, baseline changes in the gut microbiota differed among patients with depression who demonstrated varying treatment response. Currently, probiotics are an emerging treatment for depression; however, the efficacy of modulating the gut microbiota in the treatment of depression remains uncertain. Additionally, the mechanisms by which changes in the gut microbiota affect treatment response in patients with depression remain unclear. In this review, we aimed to summarize the differences in the baseline gut microbiota between the remission and non-remission groups after antidepressant therapy. Additionally, we summarized the possible mechanisms that may contribute to antidepressant resistance through the effects of the gut microbiome on the immune and nervous systems, various enzymes, bioaccumulation, and blood-brain barrier, and provide a basis for treating depression by targeting the gut microbiota.

Untargeted metabolomics identifies indole-3-propionic acid to relieve Ang II-induced endothelial dysfunction in aortic dissection

Indole-3-propionic acid (IPA), a gut microbiota-derived metabolite of tryptophan, has been proven to fulfill an essential function in cardiovascular disease (CVD) and nerve regeneration disease. However, the role of IPA in aortic dissection (AD) has not been revealed. We aimed to investigate the role of IPA in the pathogenesis of AD and the underlying mechanisms of IPA in endothelial dysfunction. Untargeted metabolomics has been employed to screen the plasma metabolic profile of AD patients in comparison with healthy individuals. Network pharmacology provides insights into the potential molecular mechanisms underlying IPA. 3-aminopropionitrile fumarate (BAPN) and angiotensin II (Ang II) were administered to induce AD in mice, while human umbilical vein endothelial cells (HUVECs) were employed for in vitro validation of the signaling pathways predicted by network pharmacology. A total of 224 potentially differential plasma metabolites were identified in the AD patients, with 110 up-regulated metabolites and 114 down-regulated metabolites. IPA was the most significantly decreased metabolite involved in tryptophan metabolism. Bcl2, caspase3, and AKT1 were predicted as the target genes of IPA by network pharmacology and molecular docking. IPA suppressed Ang II-induced apoptosis, intracellular ROS generation, inflammation, and endothelial tight junction (TJ) loss. Animal experiments demonstrated that administration of IPA alleviated the occurrence and severity of AD in mice. Taken together, we identified a previously unexplored association between tryptophan metabolite IPA and AD, providing a novel perspective on the underlying mechanism through which IPA mitigates endothelial dysfunction to protect against AD.

The Diagnosis of Intestinal Fibrosis in Crohn's Disease-Present and Future

Crohn's disease (CD) progresses with periods of remission and exacerbations. During exacerbations, chronic inflammation leads to tissue destruction. As a result, intestinal fibrosis may develop in response to the ongoing inflammatory process. Fibrosis in CD should be considered the result of the response of the intestinal wall (over) to the presence of inflammation in the deep structures of the intestinal wall. In the absence of ideal noninvasive methods, endoscopic evaluation in combination with biopsy, histopathological analysis, stool analysis, and blood analysis remains the gold standard for assessing both inflammation and fibrosis in CD. On the contrary, the ability to identify markers of intestinal fibrosis would help to develop new diagnostic and therapeutic methods to detect early stages of fibrosis. It is speculated that miRNAs may, in the future, become biomarkers for early noninvasive diagnosis in the treatment of intestinal fibrosis. The purpose of this review is to summarise existing diagnostic methods for Crohn's disease and present recent scientific reports on molecular testing.

Diet influences community dynamics following vaginal group B streptococcus colonization

The vaginal microbiota plays a pivotal role in reproductive, sexual, and perinatal health and disease. Unlike the well-established connections between diet, metabolism, and the intestinal microbiota, parallel mechanisms influencing the vaginal microbiota and pathogen colonization remain overlooked. In this study, we combine a mouse model of Streptococcus agalactiae strain COH1 [group B Streptococcus (GBS)] vaginal colonization with a mouse model of pubertal-onset obesity to assess diet as a determinant of vaginal microbiota composition and its role in colonization resistance. We leveraged culture-dependent assessment of GBS clearance and culture-independent, sequencing-based reconstruction of the vaginal microbiota in relation to diet, obesity, glucose tolerance, and microbial dynamics across time scales. Our findings demonstrate that excessive body weight gain and glucose intolerance are not associated with vaginal GBS density or timing of clearance. Diets high in fat and low in soluble fiber are associated with vaginal GBS persistence, and changes in vaginal microbiota structure and composition due to diet contribute to GBS clearance patterns in nonpregnant mice. These findings underscore a critical need for studies on diet as a key determinant of vaginal microbiota composition and its relevance to reproductive and perinatal outcomes.IMPORTANCEThis work sheds light on diet as a key determinant influencing the composition of vaginal microbiota and its involvement in group B Streptococcus (GBS) colonization in a mouse model. This study shows that mice fed diets with different nutritional composition display differences in GBS density and timing of clearance in the female reproductive tract. These findings are particularly significant given clear links between GBS and adverse reproductive and neonatal outcomes, advancing our understanding by identifying critical connections between dietary components, factors originating from the intestinal tract, vaginal microbiota, and reproductive outcomes.