The role of short-chain fatty acids in immunity, inflammation and metabolism

Association of Polyunsaturated Fatty Acid Intake on Inflammatory Gene Expression and Multiple Sclerosis: A Systematic Review and Meta-Analysis

The health benefits of omega-3 fatty acid (FA) supplementation on inflammatory gene expression (IGE) and multiple sclerosis (MS) are becoming more evident. However, an overview of the results from randomized controlled trials is lacking. This study aimed to conduct a meta-analysis to evaluate the effect of omega-3 fatty acid intake on MS (based on the criteria of the Expanded Disability Status Scale (EDSS)) and inflammatory gene expression (IGE). A search was conducted of PubMed, EMBASE, and Web of Science for cohort studies published from the inception of the database up to May 2022 that assessed the associations of omega-3 polyunsaturated fatty acids (n-3 PUFAs), docosahexaenoic acid (DHA), α-linolenic acid (ALA), and eicosapentaenoic acid (EPA) with EDSS and inflammatory gene expression (peroxisome proliferator-activated receptor gamma (PPAR-γ), tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), and interleukin-8 (IL-8)) outcomes. For the highest vs. lowest comparison, the relative risk (RR) estimates with a 95% confidence interval (CI) were pooled using the random-effect model. In total, 13 cohort studies with 1353 participants were included in the meta-analysis during periods of 3 to 144 weeks. A significant inverse relationship was found between DHA and EDSS scores (RR: 1.05; 95% CI: 0.62, 1.48; p < 0.00001). Our results also showed that omega-3 FAs significantly upregulated the gene expression of PPAR-γ (RR: 0.95; 95% CI: 0.52, 1.38; p < 0.03) and downregulated the expression of TNF-α (RR: −0.15; 95% CI: −0.99, 0.70; p < 0.00001) and IL-1 (RR: −0.60; 95% CI: −1.02, −0.18; p < 0.003). There was no clear evidence of publication bias with Egger’s tests for inflammatory gene expression (p = 0.266). Moreover, n-3 PUFAs and EPA were not significantly associated with EDSS scores (p > 0.05). In this meta-analysis of cohort studies, blood omega-3 FA concentrations were inversely related to inflammatory gene expression (IGE) and EDSS score, which indicates that they may hold great potential markers for the diagnosis, prognosis, and management of MS. However, further clinical trials are required to confirm the potential effects of the omega-3 FAs on MS disease management.

Comprehensive bibliometric and visualized analysis of research on fecal microbial transplantation published from 2000 to 2021

Background

Fecal microbial transplantation has emerged in recent years as a method of treating disease by rebuilding the intestinal flora. However, few bibliometric analyses have systematically studied this area of research. We aimed to use bibliometric analysis to visualize trends and topical research in fecal microbial transplantation to help provide insight into future trends in clinical and basic research.

Materials and methods

Articles and reviews related to fecal microbial transplantation were collected from the Web of Science Core Collection. Significant information associated with this field was visually analyzed by using Biblioshiny and CtieSpace software.

Results

A total of 3144 articles and overviews were included. The number of publications related to fecal microbial transplantation significantly increased yearly. These publications mainly came from 100 countries, led by the US and China, and 521 institutions. The most prolific and influential author is KHORUTS A. The main disciplines and application fields of fecal microbial transplantation included molecular /biology/immunology and medicine/clinical medicine, and the research foundation of fecal microbial transplantation was molecular /biology/genetics and health/nursing/medicine. An alluvial flow visualization showed several landmark articles. New developments were identified in terms of reference and keyword citation bursts. Data analysis showed that different FMT preparation and delivery methods gradually appeared as research hotspots. The main research keywords in the last 3 years were chain fatty acids, Akkermansia muciniphila, and insulin sensitivity, other keywords were current and developing research fields.

Conclusion

Research on fecal microbial transplantation is flourishing and many new applications of fecal microbial transplantation are emerging. Microbial metabolites such as short-chain fatty acids and the microbiota–gut–brain axis have become the focus of current research and are future research trends.

MicroRNA sensing and regulating microbiota-host crosstalk via diet motivation

Accumulating evidence has demonstrated that diet-derived gut microbiota participates in the regulation of host metabolism and becomes the foundation for precision-based nutritional interventions and the biomarker for potential individual dietary recommendations. However, the specific mechanism of the gut microbiota-host crosstalk remains unclear. Recent studies have identified that noncoding RNAs, as important elements in the regulation of the initiation and termination of gene expression, mediate microbiota-host communication. Besides, the cross-kingdom regulation of non-host derived microRNAs also influence microbiota-host crosstalk via diet motivation. Hence, understanding the relationship between gut microbiota, miRNAs, and host metabolism is indispensable to revealing individual differences in dietary motivation and providing targeted recommendations and strategies. In this review, we first present an overview of the interaction between diet, host genetics, and gut microbiota and collected some latest research associated with microRNAs modulated gut microbiota and intestinal homeostasis. Then, specifically described the possible molecular mechanisms of microRNAs in sensing and regulating gut microbiota-host crosstalk. Lastly, summarized the prospect of microRNAs as biomarkers in disease diagnosis, and the disadvantages of microRNAs in regulating gut microbiota-host crosstalk. We speculated that microRNAs could become potential novel circulating biomarkers for personalized dietary strategies to achieve precise nutrition in future clinical research implications.

Astragalus polysaccharides alleviates lipopolysaccharides-induced inflammatory lung injury by altering intestinal microbiota in mice

Inflammatory lung injury is a common respiratory disease with limited therapeutic effects. Increasing opinions approved that prevention is more important than drug treatment for inflammatory lung injury. Astragalus polysaccharides (APS) has multiple bioactivities including anti-inflammation and immunoregulation. However, its preventive effects on inflammatory lung injury remain unclear. In this study, mice were pretreated with APS via intragastric gavage and then were intratracheally instilled with lipopolysaccharides (LPS) to determine the role of APS in preventing lung injury. The results showed that APS pre-treatment improved the pathological changes of lung tissues, reduced the neutrophils infiltration, and inhibited the LPS-induced inflammation. Increasing evidence confirmed the close relationship between intestinal microbiota and lung inflammatory response. 16S rRNA analysis showed that APS treatment changed the microbiota composition in colon, increased the abundance of short-chain fatty acids (SCFAs)-producing genus such as Oscillospira, Akkermansia, and Coprococcus. Also, APS treatment significantly increased the serum concentrations of SCFAs including butyrate and propionate, and their anti-inflammation effects were demonstrated on mice primary alveolar macrophages. Our data confirmed the preventive effects of APS on LPS-induced lung injury, which were partly contributed by the alteration of intestinal microbiota composition and the resulting increase of serum SCFAs.

Prevalence and socioeconomic determinants of the double burden of malnutrition in mother-child pairs in Latin America and the Caribbean

Background

The double burden of malnutrition (DBM), which refers to the coexistence of overnutrition and undernutrition among populations, households or individuals, is a growing problem in low/middle-income countries. The Latin America and the Caribbean (LAC) region has been particularly affected by the DBM, following a nutrition transition and a rapid increase in overweight, obesity and diet-related disease, while high levels of undernutrition persist. This study aims to describe the prevalence of four different DBM definitions in mother-child pairs across nine LAC countries and investigate the socioeconomic determinants of overweight mothers with at least one stunted child (SCOM).

Methods

We used cross-sectional data from the Demographic and Health Surveys for all analyses. We used descriptive statistics to obtain prevalence rates and conducted multiple logistic regression analyses to investigate the association between SCOM households and socioeconomic determinants, including wealth index, maternal education, place of residency and whether the mother was working, adjusted for a range of variables.

Results

Overweight/obese mothers with at least one anaemic child were the most common type of DBM, with a prevalence of 19.39%, followed by SCOM with a prevalence of 10.44%. Statistically significant socioeconomic predictors of SCOM were households with a lower wealth index, lower maternal education and living in rural areas.

Conclusion

This study showed that the overall prevalence of most DBM definitions examined was high, which points to the need for urgent interventions in the LAC region. The unique set of socioeconomic predictors of SCOM identified in this study calls for future double-duty policies that simultaneously target food affordability, nutrition education and access to healthy food.

Leuconostoc mesenteroides utilizes glucose fermentation to produce electricity and ameliorates high-fat diet-induced abdominal fat mass

Bacteria capable of producing electricity in intestinal microbiota have been discovered. However, no studies have explored butyric acid which generated by electrogenic bacteria on the host organism have significant physiological impacts on certain organs. We found that the capacity for electrical current generation by the commensal gut Leuconostoc mesenteroides EH-1 (L. mesenteroides EH-1) during glucose fermentation. The electricity production was essential for the gut colonization of L. mesenteroides EH-1 since the inhibition of electricity production by cyclophilin A inhibitor (TMN355) significantly diminished the number of bacteria attached to the human gut epithelial cell surface. The adipocyte differentiation contributes to the increased 4-hydroxy-2-nonenal (4-HNE), considered as a biomarker of reactive oxygen species (ROS). The effect of intestinal electrogenic microbiota in the high-fat diet (HFD)-induced 4-HNE and abdominal fat accumulation in mice was investigated in this study. The oral administration of glucose with a butyric acid-producing L. mesenteroides EH-1 bacterium attenuated the expression of 4-HNE and abdominal fat. The level of 4-HNE and abdominal fat depot were markedly increased in mice administered with cyclophilin A inhibitor-pretreated bacteria or GLPG-0974, an antagonist of free fatty acid receptor 2 (Ffar2). Our studies suggest a novel means by which the probiotic bacteria can modulate fat mass deposition and oxidative stress via the cyclophilin A-mediated electron production and the butyric acid-activated Ffar2 pathway.

Effects of atherogenic diet supplemented with fermentable carbohydrates on metabolic responses and plaque formation in coronary arteries using a Saddleback pig model

Fermentable carbohydrates are gaining interest in the field of human nutrition because of their benefits in obesity-related comorbidities. The aim of this study was to investigate the influence of fermentable carbohydrates, such as pectin and inulin, in an atherogenic diet on metabolic responses and plaque formation in coronary arteries using a Saddleback pig model. Forty-eight healthy pigs aged five months were divided into four feeding groups (n = 10) and one baseline group (n = 8). Three feeding groups received an atherogenic diet (38% crisps, 10% palm fat, and 2% sugar with or without supplementation of 5% pectin or inulin), and one group received a conventional diet over 15 weeks. Feed intake, weight gain, body condition score, and back fat thickness were monitored regularly. Blood and fecal samples were collected monthly to assess the metabolites associated with high cardiovascular risk and fat content, respectively. At the end of 15 weeks, the coronary arteries of the pigs were analyzed for atherosclerotic plaque formation. Independent of supplementation, significant changes were observed in lipid metabolism, such as an increase in triglycerides, bile acids, and cholesterol in serum, in all groups fed atherogenic diets in comparison to the conventional group. Serum metabolome analysis showed differentiation of the feeding groups by diet (atherogenic versus conventional diet) but not by supplementation with pectin or inulin. Cardiovascular lesions were found in all feeding groups and in the baseline group. Supplementation of pectin or inulin in the atherogenic diet had no significant impact on cardiovascular lesion size. Saddleback pigs can develop naturally occurring plaques in coronary arteries. Therefore, this pig model offers potential for further research on the effects of dietary intervention on obesity-related comorbidities, such as cardiovascular lesions, in humans.

Dietary Polysaccharides as Modulators of the Gut Microbiota Ecosystem: An Update on Their Impact on Health

A polysaccharide is a macromolecule composed of more than ten monosaccharides with a wide distribution and high structural diversity and complexity in nature. Certain polysaccharides are immunomodulators and play key roles in the regulation of immune responses during the progression of some diseases. In addition to stimulating the growth of certain intestinal bacteria, polysaccharides may also promote health benefits by modulating the gut microbiota. In the last years, studies about the triad gut microbiota-polysaccharides-health have increased exponentially. In consequence, in the present review, we aim to summarize recent knowledge about the function of dietary polysaccharides on gut microbiota composition and how these effects affect host health.

Phthalates released from microplastics inhibit microbial metabolic activity and induce different effects on intestinal luminal and mucosal microbiota

The intestine is not only the main accumulation organ of microplastics (MPs), but also the intestinal environment is very conductive to the release of additives in MPs. However, the kinetics of release process, influence factors, and the related effects on gut microbiota remain largely unknown. In this study, a mucosal-simulator of the human intestinal microbial ecosystem (M-SHIME) was used to investigate the influence of gut microbiota on the release of phthalates (PAEs) from MPs and the effects of MPs on the intestinal luminal microbiota and mucosal microbiota. We found that di-(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), and dimethyl phthalate (DMP) were the dominant PAEs released in the gut. Gut microbiota accelerated the release of PAEs, with the time to reach the maximum release was shortened from 7 days to 2 days. Moreover, MPs induced differential effects on luminal microbiota and mucosal microbiota. Compared with mucosal microbiota, the luminal microbiota was more susceptible to the leaching of PAEs from MPs, as evidenced by more microbiota alterations. MPs also inhibited the metabolic activity of intestinal flora based on the reduced production of short chain fatty acids (SCFA). These effects were mainly contributed by the release of PAEs. Acidaminococcus and Morganella were simultaneously correlated to the release of PAEs and the inhibition of metabolic activity of intestinal microbiota and can be used as indicators for the intestinal exposure of MPs and additives.

Influence of the Gut Microbiota on the Development of Neurodegenerative Diseases

Neurodegenerative disorders are marked by neuronal death over time, causing a variety of cognitive and motor dysfunctions. Protein misfolding, neuroinflammation, and mitochondrial and protein clearance system dysfunction have all been identified as common pathways leading to neurodegeneration in recent decades. An altered microbiome of the gut, which is considered to play a central role in diseases as well as health, has recently been identified as another potential feature seen in neurodegenerative disorders. An array of microbial molecules that are released in the digestive tract may mediate gut-brain connections and permeate many organ systems, including the nervous system. Furthermore, recent findings from clinical as well as preclinical trials suggest that the microbiota of the gut plays a critical part in gut-brain interplay and that a misbalance in the composition of the gut microbiome may be linked to the etiology of neurological disorders (majorly neurodegenerative health problems); the underlying mechanism of which is still unknown. The review aims to consider the association between the microbiota of the gut and neurodegenerative disorders, as well as to add to our understanding of the significance of the gut microbiome in neurodegeneration and the mechanisms that underlie it. Knowing the mechanisms behind the gut microbiome's role and abundance will provide us with new insights that could lead to novel therapeutic strategies.

Effects of alcoholic fermentation on the non-volatile and volatile compounds in grapefruit (Citrus paradisi Mac. cv. Cocktail) juice: A combination of UPLC-MS/MS and gas chromatography ion mobility spectrometry analysis

Grapefruit has attracted much attention as a functional fruit, of which “Cocktail” is a special variety with low acidity. The present study aimed to investigate the effects of alcoholic fermentation on the non-volatile and volatile compounds of “Cocktail” grapefruit juice. To analyze, a non-targeted metabolomics method based on UPLC-MS/MS and volatiles analysis using GC-IMS were performed. A total of 1015 phytochemicals were identified, including 296 flavonoids and 145 phenolic acids, with noticeably increasing varieties and abundance following the fermentation. Also 57 volatile compounds were detected, and alcoholic fermentation was effective in modulating aromatic profiles of grapefruit juice, with terpenes and ketones decreasing, and alcohols increasing together with esters. Citraconic acid and ethyl butanoate were the most variable non-volatile and volatile substances, respectively. The results provide a wealth of information for the study of “Cocktail” grapefruit and will serve as a valuable reference for the large-scale production of grapefruit fermented juice in the future.

Beneficial Effects of Anti-Inflammatory Diet in Modulating Gut Microbiota and Controlling Obesity

Obesity has consistently been associated with an increased risk of metabolic abnormalities such as diabetes, hyperlipidemia, and cardiovascular diseases, as well as the development of several types of cancer. In recent decades, unfortunately, the rate of overweight/obesity has increased significantly among adults and children. A growing body of evidence shows that there is a relationship between metabolic disorders such as obesity and the composition of the gut microbiota. Additionally, inflammation is considered to be a driving force in the obesity-gut microbiota connection. Therefore, it seems that anti-inflammatory nutrients, foods, and/or diets can play an essential role in the management of obesity by affecting the intestinal flora and controlling inflammatory responses. In this review, we describe the links between the gut microbiota, obesity, and inflammation, and summarize the benefits of anti-inflammatory diets in preventing obesity.

Uncovering the biogeography of the microbial commmunity and its association with nutrient metabolism in the intestinal tract using a pig model

The gut microbiota is a complex ecosystem that is essential for the metabolism, immunity and health of the host. The gut microbiota also plays a critical role in nutrient absorption and metabolism, and nutrients can influence the growth and composition of the gut microbiota. To gain a better understanding of the relationship between the gut microbial composition and nutrient metabolism, we used a pig model by collecting the contents of the different intestinal locations from six pigs to investigate microbial composition in different intestinal locations based on 16S rRNA gene sequencing and the concentrations of short-chain fatty acids (SCFAs), amino acids, fat, and crude ash in different intestinal locations using gas chromatography and chemical analysis. The results showed that the richness and diversity of intestinal microbial communities gradually increased from the small intestine to the large intestine. The relative abundance of Proteobacteria was higher in the jejunum and ileum, whereas the proportion of Firmicutes was higher in the cecum and colon. The concentrations of SCFAs were higher in the cecum and colon (P < 0.05). The concentrations of amino acids were higher in the small intestine than in the large intestine, while the amino acid content was significantly higher in the ascending colon than in the transverse colon and descending colon. The correlation analysis revealed that Ruminococcaceae UCG-005, Coriobacteriaceae_uncultured, [Eubacterium] hallii group, Mogibacterium and Lachnospiraceae AC2044 group had a higher positive correlation with SCFAs, crude ash and fat but had a negative correlation with amino acids in different gut locations of pigs. These findings may serve as fundamental data for using nutrient metabolism to regulate human and animal gut microbes and health and provide guidance for exploring host-microbe bidirectional interaction mechanisms and driving pathways.

Modulation of Intestinal Flora by Dietary Polysaccharides: A Novel Approach for the Treatment and Prevention of Metabolic Disorders

Intestinal flora is numerous and diverse, and play a key role in maintaining human health. Dietary polysaccharides are widely present in the daily diet and have a moderating effect on the intestinal flora. Past studies have confirmed that intestinal flora is involved in the metabolic process in the human body, and the change in intestinal flora structure is closely related to the metabolic disorders in the human body. Therefore, regulating intestinal flora through dietary polysaccharides is an effective way to treat and prevent common metabolic diseases and has great research value. However, this area has not received enough attention. In this review, we provide an overview of the modulatory effects of dietary polysaccharides on intestinal flora and the key role of intestinal flora in improving metabolic disorders in humans. In addition, we highlight the therapeutic and preventive effects of intestinal flora modulation through dietary polysaccharides on metabolic disorders, aiming to find new ways to treat metabolic disorders and facilitate future exploration in this field.

Short Chain Fatty Acids (SCFAs) Are the Potential Immunomodulatory Metabolites in Controlling Staphylococcus aureus-Mediated Mastitis

Mastitis is an emerging health concern in animals. An increased incidence of mastitis in dairy cows has been reported in the last few years across the world. It is estimated that up to 20% of cows are suffering from mastitis, causing incompetency in the mucosal immunity and resulting in excessive global economic losses in the dairy industry. Staphylococcus aureus (S. aureus) has been reported as the most common bacterial pathogen of mastitis at clinical and sub-clinical levels. Antibiotics, including penicillin, macrolides, lincomycin, cephalosporins, tetracyclines, chloramphenicol, and methicillin, were used to cure S. aureus-induced mastitis. However, S. aureus is resistant to most antibiotics, and methicillin-resistant S. aureus (MRSA) especially has emerged as a critical health concern. MRSA impairs immune homeostasis leaving the host more susceptible to other infections. Thus, exploring an alternative to antibiotics has become an immediate requirement of the current decade. Short chain fatty acids (SCFAs) are the potent bioactive metabolites produced by host gut microbiota through fermentation and play a crucial role in host/pathogen interaction and could be applied as a potential therapeutic agent against mastitis. The purpose of this review is to summarize the potential mechanism by which SCFAs alleviate mastitis, providing the theoretical reference for the usage of SCFAs in preventing or curing mastitis.

Modulating Microbiota as a New Strategy for Breast Cancer Prevention and Treatment

Breast cancer (BC) is the most common cancer in women in the United States. There has been an increasing incidence and decreasing mortality rate of BC cases over the past several decades. Many risk factors are associated with BC, such as diet, aging, personal and family history, obesity, and some environmental factors. Recent studies have shown that healthy individuals and BC patients have different microbiota composition, indicating that microbiome is a new risk factor for BC. Gut and breast microbiota alterations are associated with BC prognosis. This review will evaluate altered microbiota populations in gut, breast tissue, and milk of BC patients, as well as mechanisms of interactions between microbiota modulation and BC. Probiotics and prebiotics are commercially available dietary supplements to alleviate side-effects of cancer therapies. They also shape the population of human gut microbiome. This review evaluates novel means of modulating microbiota by nutritional treatment with probiotics and prebiotics as emerging and promising strategies for prevention and treatment of BC. The mechanistic role of probiotic and prebiotics partially depend on alterations in estrogen metabolism, systematic immune regulation, and epigenetics regulation.

Like mother, like child: The maternal microbiome impacts offspring asthma

The link between the maternal microbiome and offspring allergy is poorly defined. McCauley and colleagues now demonstrate that heritable bacteria are associated with infant asthma susceptibility and induce immunosuppression of allergic inflammation, suggesting significant implications for asthma-preventative interventions¹.

Limosilactobacillus fermentum-fermented ginseng improved antibiotic-induced diarrhoea and the gut microbiota profiles of rats

AIMS

This study investigated the efficacy of Limosilactobacillus fermentum-fermented ginseng for improving colitis and the gut microbiota profiles in rats and explored the benefits of the L. fermentum fermentation process to ginseng.

METHODS AND RESULTS

Ginseng polysaccharide and ginsenoside from fermented ginseng were analysed by UV and HPLC. Antibiotic-fed rats were treated with fermented ginseng and a L. fermentum-ginseng mixture. Histopathology- and immune-related factors (TNF-α, IL-1β, IL-6 and IL-10) of the colon were assayed by using pathological sections and ELISA. After treatment, fermented ginseng relieved the symptoms of antibiotic-induced diarrhoea and colon inflammation, and the expression of colon immune factors returned to normal. The gut microbial communities were identified by 16S rRNA gene sequencing. The results showed that the alterations in the gut microbiota returned to normal. In addition, the gut microbiota changes were correlated with immune factor expression after treatment. The fermented ginseng had better biological functions than a L. fermentum-ginseng mixture.

CONCLUSIONS

Fermented ginseng can relieve diarrhoea and colon inflammation and restore the gut microbiota to its original state. The process of L. fermentum fermentation can expand the therapeutic use of ginseng.

SIGNIFICANCE AND IMPACT OF THE STUDY

This research suggested the potential function of fermented ginseng to relieve diarrhoea and recover the gut microbiota to a normal level and explored the benefits of the Limosilactobacillus fermentum fermentation process to ginseng.

The landscape in the gut microbiome of long-lived families reveals new insights on longevity and aging - relevant neural and immune function

Human longevity has a strong familial and genetic component. Dynamic characteristics of the gut microbiome during aging associated with longevity, neural, and immune function remained unknown. Here, we aim to reveal the synergistic changes in gut microbiome associated with decline in neural and immune system with aging and further obtain insights into the establishment of microbiome homeostasis that can benefit human longevity. Based on 16S rRNA and metagenomics sequencing data for 32 longevity families including three generations, centenarians, elderly, and young groups, we found centenarians showed increased diversity of gut microbiota, severely damaged connection among bacteria, depleted in microbial-associated essential amino acid function, and increased abundance of anti-inflammatory bacteria in comparison to young and elderly groups. Some potential probiotic species, such as Desulfovibrio piger, Gordonibacter pamelaeae, Odoribacter splanchnicus, and Ruminococcaceae bacterium D5 were enriched with aging, which might possibly support health maintenance. The level of Amyloid-β (Aβ) and brain-derived neurotrophic factor (BDNF) related to neural function showed increased and decreased with aging, respectively. The elevated level of inflammatory factors was observed in centenarians compared with young and elderly groups. The enriched Bacteroides fragilis in centenarians might promote longevity through up-regulating anti-inflammatory factor IL-10 expression to mediate the critical balance between health and disease. Impressively, the associated analysis for gut microbiota with the level of Aβ, BDNF, and inflammatory factors suggests Bifidobacterium pseudocatenulatum could be a particularly beneficial bacteria in the improvement of impaired neural and immune function. Our results provide a rationale for targeting the gut microbiome in future clinical applications of aging-related diseases and extending life span.Abbreviations: 16S rRNA: 16S ribosomal RNA; MAGs: Metagenome-assembled genomes; ASVs: Amplicon sequence variants; DNA: Deoxyribonucleic acid; FDR: False discovery rate: KEGG: Kyoto Encyclopedia of Genes and Genomes; PCoA: Principal coordinates analysis; PCR: Polymerase chain reaction; PICRUSt: Phylogenetic Investigation of Communities by Reconstruction of Unobserved States; Aβ: Amyloid-β (Aβ); BDNF: Brain-derived neurotrophic factor.

Typical antibiotic exposure and dysglycemia risk in an elderly Chinese population

Studies examined the connection between antibiotic exposure in urine and dysglycemia risk (including prediabetes and diabetes) in the elderly were limited. Multiple linear regression, binary logistic regression, restricted cubic splines (RCS), and stratified analysis were applied to analyze the relationship between antibiotic exposure and dysglycemia risk. We observed that sulfaclozine exposure 0.07 (95% confidence interval [CI]: 0.01-0.23) significantly increased fasting blood glucose (FBG) level. By mechanism, usage, and antimicrobial action, sulfonamides 0.08 (95% CI: 0.06-0.36), veterinary antibiotics (VA) 0.07 (95% CI: 0.01-0.30), or bacteriostatic antibiotics 0.07 (95% CI: 0.02-0.29) significantly increased FBG level. Additionally, sulfaclozine exposure 1.54 (95% CI: 1.02-2.33) resulted in a higher dysglycemia risk, while doxycycline exposure 0.53 (95% CI: 0.30-0.95) resulted in a lower dysglycemia risk. By mechanism, usage, and antimicrobial action, sulfonamides 1.44 (95% CI: 1.02-2.04), VA 1.68 (95% CI: 1.21-2.35), or bacteriostatic antibiotics 1.40 (95% CI: 1.02-1.93) exposure had a higher dysglycemia risk. Taken together, exposure to sulfonamides, VA, especially sulfaclozine, was correlated with a higher dysglycemia risk in the elderly. Exposure to bacteriostatic antibiotics was associated with a higher dysglycemia risk in the female.

Association of gut microbiota with sort-chain fatty acids and inflammatory cytokines in diabetic patients with cognitive impairment: A cross-sectional, non-controlled study

Emerging evidence suggests that gut microbiota, short-chain fatty acids (SCFAs), and inflammatory cytokines play important roles in the pathogenesis of diabetic cognitive impairment (DCI). However, little is known about alterations of gut microbiota and SCFA levels as well as the relationships between inflammatory cytokines and cognitive function in Chinese DCI patients. Herein, the differences in the gut microbiota, plasma SCFAs, and inflammatory cytokines in DCI patients and type 2 diabetes mellitus (T2DM) patients were explored. A cross-sectional study of 30 DCI patients and 30 T2DM patients without mild cognitive impairment (MCI) was conducted in Tianjin city, China. The gut microbiota, plasma SCFAs, and inflammatory cytokines were determined using 16S ribosomal RNA (rRNA) gene sequencing, gas chromatography-mass spectrometry (GC-MS), and Luminex immunofluorescence assays, respectively. In addition, the correlation between gut microbiota and DCI clinical characteristics, SCFAs, and inflammatory cytokines was investigated. According to the results, at the genus level, DCI patients presented a greater abundance of Gemmiger, Bacteroides, Roseburia, Prevotella, and Bifidobacterium and a poorer abundance of Escherichia and Akkermansia than T2DM patients. The plasma concentrations of acetic acid, propionic acid, isobutyric acid, and butyric acid plummeted in DCI patients compared to those in T2DM patients. TNF-α and IL-8 concentrations in plasma were significantly higher in DCI patients than in T2DM patients. Moreover, the concentrations of acetic acid, propionic acid, butyric acid, and isovaleric acid in plasma were negatively correlated with TNF-α, while those of acetic acid and butyric acid were negatively correlated with IL-8. Furthermore, the abundance of the genus Alloprevotella was negatively correlated with butyric acid, while that of Holdemanella was negatively correlated with propanoic acid and isobutyric acid. Fusobacterium abundance was negatively correlated with propanoic acid. Clostridium XlVb abundance was negatively correlated with TNF-α, while Shuttleworthia abundance was positively correlated with TNF-α. It was demonstrated that the gut microbiota alterations were accompanied by a change in SCFAs and inflammatory cytokines in DCI in Chinese patients, potentially causing DCI development. These findings might help to identify more effective microbiota-based therapies for DCI in the future.

Commensal microbe-derived SCFA alleviates atrial fibrillation via GPR43/NLRP3 signaling

Rationale: Dysbiotic gut microbiota (GM) and NLRP3 inflammasome are proarrhythmic factors in atrial fibrillation (AF). Herein, whether short-chain fatty acid (SCFA) produced from GM fermentation of dietary fiber serving as invisible mediators is yet unclear. Thus, the current study aimed to determine whether SCFA alleviated from NLRP3 signaling-mediated atrial remodeling protects AF development. Methods: First, a cross-sectional study based on the GC-MS metabolomics was performed to explore the association between fecal SCFA levels and AF traits in a cohort consisted of 48 individuals. Then, a well-established mice model fed diet deficient or enriched in dietary fiber was established to elucidate the pathophysiological role of SCFA involved in AF susceptibility, atrial remodeling, and G-protein-coupled receptor 43 (GPR43)/NLRP3 signaling. Finally, the effects of SCFA were verified on HL-1 cells. Results: Fecal SCFA levels were remarkably reduced in AF patients with a declining trend from paroxysmal to persistent AF. Prolonged P wave duration based on surface ECG and increased left atrial diameter gained from echocardiography was identified in low-fiber diet mice but lost in SCFA-supplemented group. Lack of dietary fiber enhanced susceptibility to AF under burst pacing, whereas SCFA might exert a protective effect. The supplementation of SCFA prevented dietary fiber deficiency-upregulated phosphorylation of calmodulin-dependent protein kinase II and ryanodine receptor 2, the disarray fibrosis, collagen expression, and NLRP3 inflammasome activation in atrial tissue. Finally, the AF protective roles of SCFA were identified through GPR43 mediated deactivation of NLRP3 by GPR43 knockdown in HL-1 cells. Conclusions: SCFA derived from dietary fiber fermentation by gut commensals alleviates AF development via GPR43/NLRP3 signaling.

Determination of short-chain fatty acids by N,N-dimethylethylenediamine derivatization combined with liquid chromatography/mass spectrometry and their implication in influenza virus infection

Short-chain fatty acids (SCFAs) are the end products of the fermentation of complex carbohydrates by the gut microbiota. Although SCFAs are recognized as important markers to elucidate the link between gut health and disease, it has been difficult to analyze SCFAs with mass spectrometry technologies due to their poor ionization efficiency and high volatility. Here, we present a novel and sensitive method for the quantification of SCFAs, including C2-C6 SCFAs and their hydroxy derivatives, by liquid chromatography/tandem mass spectrometry (LC-MS/MS) upon N,N-dimethylethylenediamine (DMED) derivatization with a run time of 10 min. Moreover, the quantification method of DMED-derivatized SCFAs in intestinal contents using isotope-labeled internal standards was also established. The method validation was performed by analyzing spiked intestinal samples; the limits of detection and quantification of SCFAs with this method were found to be 0.5 and 5 fmol, respectively; the recovery was greater than 80% and good linearity (0.9932 to 0.9979) of calibration curves was obtained over the range from 0.005 to 5000 pmol/μL; the intraday and interday precisions were achieved in the range of 1-5%. Furthermore, the validated method was applied to analyze SCFAs in the cecum and colon contents of mice infected with the influenza virus. The results showed that the concentration of most of the SCFAs tested here decreased significantly in a time-dependent manner after the infection, suggesting a possibility that SCFAs in intestinal samples could be used as severe disease markers. Overall, we here successfully developed a simple, fast, and sensitive method for SCFA analysis by LC-MS/MS combined with DMED derivatization. The method for the quantification of SCFAs will be a useful tool for both basic research and clinical studies.

Traumatic spinal cord injury and the contributions of the post-injury microbiome

Spinal cord injuries are an enormous burden on injured individuals and their caregivers. The pathophysiological effects of injury are not limited to the spine and limb function, but affect numerous body systems. Growing observations in human studies and experimental models suggest that the gut microbiome is altered following spinal cord injury. Given the importance of signals derived from the gut microbiome for host physiology, it is possible that injury-triggered dysbiosis subsequently affects aspects of recovery. Here, we review emerging literature on the role of the microbiome following spinal cord injury. Specifically, we highlight findings from both human and experimental studies that correlate taxonomic changes to aspects of injury recovery. Examination of both observational and emerging interventional studies supports the notion that future therapeutic avenues for spinal cord injury pathologies may lie at the interface of the host and indigenous microbes.

Lacticaseibacillus rhamnosus LS8 Ameliorates Azoxymethane/Dextran Sulfate Sodium-Induced Colitis-Associated Tumorigenesis in Mice via Regulating Gut Microbiota and Inhibiting Inflammation

Gut microbiota dysbiosis may promote the process of colorectal cancer (CRC). Lacticaseibacillus rhamnosus LS8 (LRL) is a potential gut microbiota regulating strain because it can produce a novel antimicrobial substance (like cycloalanopine). In addition, this probiotic had an inflammation-ameliorating effect on the dextran sulfate sodium (DSS)-induced colitis mice. However, it is not known whether treatment with this probiotic could ameliorate colitis-associated CRC via regulating gut microbiota. In this study, a CRC mouse model was induced by a single intraperitoneal injection of azoxymethane (AOM, 10 mg/kg) and followed by three 7-day cycles of 2% DSS administration. Results showed that LRL could inhibit tumor formation. Moreover, LRL enhanced the gut barrier by preventing goblet cell loss and promoting the expression of ZO-1, occludin, and claudin-1. Furthermore, LRL ameliorated gut microbiota dysbiosis, which was conducive to the growth of beneficial bacteria (e.g., Faecalibaculum and Akkermansia), and further led to an increase in SCFAs and a decrease in LPS. In addition, LRL alleviated colonic inflammation by inhibiting the overexpression of TLR4/NF-κB, pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-γ, and IL-17a), and chemokines (Cxcl1, Cxcl2, Cxcl3, Cxcl5, and Cxcl7). In conclusion, LRL could alleviate CRC by regulating gut microbiota and preventing gut barrier damage and inflammation.

Urolithins and intestinal health

There are trillions of microorganisms in the human intestine. They can react to the intestinal microenvironment by metabolizing food or producing small molecular compounds to affect the host's digestive ability and resist the risk of infection and autoimmune diseases. Many studies have revealed that intestinal flora and its metabolites play an important role in human physiology and the development of diseases. Urolithins are kind of intestinal microbiota metabolites of ellagitannins (ETs) and ellagic acid (EA) with potent biological activity in vivo. However, different individuals have different intestinal flora. According to the different metabolites from ETs and EA, it is divided into three metabo-types including UM-A, UM-B and UM-0. This paper reviews the origin of urolithins, the urolithin producing microorganisms and the effects of urolithins on regulating intestinal diseases. This review will provide a theoretical basis for the regulation of urolithins in the homeostasis of intestinal flora and a reference for the scientific utilization of urolithins and foods rich in ETs and EA.

The Pathological Mechanism Between the Intestine and Brain in the Early Stage of Parkinson's Disease

Parkinson's disease (PD) is the second most common chronic progressive neurodegenerative disease. The main pathological features are progressive degeneration of neurons and abnormal accumulation of α-synuclein. At present, the pathogenesis of PD is not completely clear, and many changes in the intestinal tract may be the early pathogenic factors of PD. These changes affect the central nervous system (CNS) through both nervous and humoral pathways. α-Synuclein deposited in the intestinal nerve migrates upward along the vagus nerve to the brain. Inflammation and immune regulation mediated by intestinal immune cells may be involved, affecting the CNS through local blood circulation. In addition, microorganisms and their metabolites may also affect the progression of PD. Therefore, paying attention to the multiple changes in the intestinal tract may provide new insight for the early diagnosis and treatment of PD.

The gut-lung axis in severe acute Pancreatitis-associated lung injury: The protection by the gut microbiota through short-chain fatty acids

The role of gut microbiota in regulating the intestinal homeostasis, as well as the pathogenesis of severe acute pancreatitis-associated lung injury (PALI) is widely recognized. The bioactive functions of metabolites with small molecule weight and the detail molecular mechanisms of PALI mediated by "gut-lung axis" have gradually raised the attentions of researchers. Several studies have proved that short-chain fatty acids (SCFAs) produced by gut microbiome play crucial roles and varied activities in the process of PALI. However, relevant reviews reporting SCFAs in the involvement of PALI is lacking. In this review, we firstly introduced the synthetic and metabolic pathways of SCFAs, as well as the transport and signal transduction routes in brief. Afterwards, we focused on the possible mechanisms and clues of SCFAs to participate in the fight against PALI which referred to the inhibition of pathogen proliferation, anti-inflammatory effects, enhancement of intestinal barrier functions, and the maintenance and regulation of immune homeostasis via pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). In addition, the latest reported pathological and physiological mechanisms of the gut-lung axis involved in PALI were reviewed. Finally, we summarized the potential therapeutic interventions of PALI by targeting SCFAs, including dietary fiber supplementation, direct supplementation of SCFAs/prebiotics/probiotics, and drugs administration, which is expected to provide new sights for clinical use in the future.

Faecal Microbiota Transplantation and Chronic Kidney Disease

Faecal microbiota transplantation (FMT) has attracted increasing attention as an intervention in many clinical conditions, including autoimmune, enteroendocrine, gastroenterological, and neurological diseases. For years, FMT has been an effective second-line treatment for Clostridium difficile infection (CDI) with beneficial outcomes. FMT is also promising in improving bowel diseases, such as ulcerative colitis (UC). Pre-clinical and clinical studies suggest that this microbiota-based intervention may influence the development and progression of chronic kidney disease (CKD) via modifying a dysregulated gut–kidney axis. Despite the high morbidity and mortality due to CKD, there are limited options for treatment until end-stage kidney disease occurs, which results in death, dialysis, or kidney transplantation. This imposes a significant financial and health burden on the individual, their families and careers, and the health system. Recent studies have suggested that strategies to reverse gut dysbiosis using FMT are a promising therapy in CKD. This review summarises the preclinical and clinical evidence and postulates the potential therapeutic effect of FMT in the management of CKD.

Fatty acids role in multiple sclerosis as "metabokines"

Multiple sclerosis (MS), as an autoimmune neurological disease with both genetic and environmental contribution, still lacks effective treatment options among progressive patients, highlighting the need to re-evaluate disease innate properties in search for novel therapeutic targets. Fatty acids (FA) and MS bear an interesting intimate connection. FA and FA metabolism are highly associated with autoimmunity, as the diet-derived circulatory and tissue-resident FAs level and composition can modulate immune cells polarization, differentiation and function, suggesting their broad regulatory role as “metabokines”. In addition, FAs are indeed protective factors for blood–brain barrier integrity, crucial contributors of central nervous system (CNS) chronic inflammation and progressive degeneration, as well as important materials for remyelination. The remaining area of ambiguity requires further exploration into this arena to validate the existed phenomenon, develop novel therapies, and confirm the safety and efficacy of therapeutic intervention targeting FA metabolism.

Rice hull insoluble dietary fiber alleviated experimental colitis induced by low dose of dextran sulfate sodium in cadmium-exposed mice

Cadmium (Cd), an important toxic environmental pollutant, can invade the gastrointestinal tract and induce the occurrence of gastrointestinal diseases. This study aimed to investigate the protective effect of rice hull insoluble dietary fiber (RHF) on Cd-promoted colitis induced by low dose of dextran sulfate sodium. Administration of RHF attenuated inflammation by limiting Cd accumulation and regulating intestinal immune homeostasis in colitis mice with Cd exposure. RHF could maintain the structure of the gut barrier by increasing mucin secretion and intestinal tight connectivity in mice. Subsequently, RHF repressed the colonic inflammation mediated by the TLR4/MyD88/NF-κB pathway, and inhibited the transcription regulation of inflammatory cytokines. Furthermore, RHF showed an enhancement of a variety of probiotics, such as Eubacterium and Faecalibaculum. RHF also inhibited the growth of pathogenic bacteria, including Erysipelatoclostridium, Helicobacter and Bacteroides. The growth of beneficial bacteria was also accompanied by reversing the decline in short-chain fatty acids, supporting the initial potentiality of RHF as a prebiotic in cases of damage by Cd exposure in colitis mice. Importantly, RHF also remained resistant to Cd toxicity in colitis mice when the gut microbiota was depleted by antibiotics. We suggest that RHF could be used as a novel dietary supplement strategy against Cd-exacerbated colitis.

Prevention of Ulcerative Colitis in Mice by Sweet Tea (Lithocarpus litseifolius) via the Regulation of Gut Microbiota and Butyric-Acid-Mediated Anti-Inflammatory Signaling

Sweet tea (Lithocarpus litseifolius [Hance] Chun) is a new resource for food raw materials, with plenty of health functions. This study aimed to investigate the preventive effect and potential mechanism of sweet tea extract (STE) against ulcerative colitis (UC). Briefly, BABL/c mice were treated with STE (100 and 400 mg/kg) for 2 weeks to prevent 3% dextran sulfate sodium (DSS)-induced UC. It was found that STE supplementation significantly prevented DSS-induced UC symptoms; suppressed the levels of pro-inflammatory mediators, such as myeloperoxidase and tumor necrosis factor-α; increased the levels of anti-inflammatory cytokines; and up-regulated the expression of tight junction proteins (Zonula occludens-1 and Occludin). STE also altered the gut microbiota profile of UC mice by increasing Bacteroidetes, Lactobacillus, Akkermansia, Lachnospiraceae_NK4A136_group, and Alistipes and inhibiting Firmicutes, Proteobacteria, and Helicobacter, accompanied by a significant increase in the content of butyric acid. Moreover, STE increased the expression of G-protein-coupled receptor (GPR) 43 and GPR109A and inhibited the expression of histone deacetylase 3 (HDAC3) and nuclear factor-κB p65 (NF-κB p65) in the colon. In conclusion, this study indicated that STE has a good preventive effect on UC by regulating gut microbiota to activate butyrate-GPR-mediated anti-inflammatory signaling and simultaneously inhibit HDAC3/NF-κB inflammatory signaling.

NLRX1 Deficiency Alters the Gut Microbiome and Is Further Exacerbated by Adherence to a Gluten-Free Diet

Patients with gluten sensitivities present with dysbiosis of the gut microbiome that is further exacerbated by a strict adherence to a gluten-free diet (GFD). A subtype of patients genetically susceptible to gluten sensitivities are Celiac Disease (CeD) patients, who are carriers of the HLA DR3/DQ2 or HLA DR4/DQ8 haplotypes. Although 85-95% of all CeD patients carry HLA DQ2, up to 25-50% of the world population carry this haplotype with only a minority developing CeD. This suggests that CeD and other gluten sensitivities are mediated by factors beyond genetics. The contribution of innate immune system signaling has been generally understudied in the context of gluten sensitivities. Thus, here we examined the role of NOD-like receptors (NLRs), a subtype of pattern recognition receptors, in maintaining the composition of the gut microbiome in animals maintained on a GFD. Human transcriptomics data revealed significant increases in the gene expression of multiple NLR family members, across functional groups, in patients with active CeD compared to control specimens. However, NLRX1 was uniquely down-regulated during active disease. NLRX1 is a negative regulatory NLR that functions to suppress inflammatory signaling and has been postulate to prevent inflammation-induced dysbiosis. Using Nlrx1^-/- mice maintained on either a normal or gluten-free diet, we show that loss of NLRX1 alters the microbiome composition, and a distinctive shift further ensues following adherence to a GFD, including a reciprocal loss of beneficial microbes and increase in opportunistic bacterial populations. Finally, we evaluated the functional impact of an altered gut microbiome by assessing short- and medium-chain fatty acid production. These studies revealed significant differences in a selection of metabolic markers that when paired with 16S rRNA sequencing data could reflect an overall imbalance and loss of immune system homeostasis in the gastrointestinal system.

Pu-erh Tea Restored Circadian Rhythm Disruption by Regulating Tryptophan Metabolism

Pu-erh tea is a healthy beverage rich in phytochemicals, and its effect on the risk of inducing circadian rhythm disorders (CRD) is unclear. In this study, healthy mice were given water or 0.25% (w/v) Pu-erh tea for 7 weeks, followed by a 40 day disruption of the light/dark cycle. CRD caused dysregulation of neurotransmitter secretion and clock gene oscillations, intestinal inflammation, and disruption of intestinal microbes and metabolites. Pu-erh tea boosted the indole and 5-hydroxytryptamine pathways of tryptophan metabolism via the gut-liver-brain axis. Furthermore, its metabolites (e.g., IAA, Indole, 5-HT) enhanced hepatic glycolipid metabolism and down-regulated intestinal oxidative stress by improving the brain hormone release. Tryptophan metabolites and bile acids also promoted liver lipid metabolism and inhibited intestinal inflammation (MyD88/NF-κB) via the enterohepatic circulation. Collectively, 0.25% (w/v) Pu-erh tea has the potential to prevent CRD by promoting indole and 5-HT pathways of tryptophan metabolism and signaling interactions in the gut-liver-brain axis.

Intake of Natural, Unprocessed Tiger Nuts (Cyperus esculentus L.) Drink Significantly Favors Intestinal Beneficial Bacteria in a Short Period of Time

Horchata is a natural drink obtained from tiger nut tubers (Cyperus esculentus L.). It has a pleasant milky aspect and nutty flavor; some health benefits have been traditionally attributed to it. This study evaluated the effects of an unprocessed horchata drink on the gut microbiota of healthy adult volunteers (n = 31) who consumed 300 mL of natural, unprocessed horchata with no added sugar daily for 3 days. Although there were no apparent microbial profile changes induced by horchata consumption in the studied population, differences could be determined when volunteers were segmented by microbial clusters. Three distinctive enterogroups were identified previous to consuming horchata, respectively characterized by the relative abundances of Blautia and Lachnospira (B1), Bacteroides (B2) and Ruminococcus and Bifidobacterium (B3). After consuming horchata, samples of all volunteers were grouped into two clusters, one enriched in Akkermansia, Christenellaceae and Clostridiales (A1) and the other with a remarkable presence of Faecalibacterium, Bifidobacterium and Lachnospira (A2). Interestingly, the impact of horchata was dependent on the previous microbiome of each individual, and its effect yielded microbial profiles associated with butyrate production, which are typical of a Mediterranean or vegetable/fiber-rich diet and could be related to the presence of high amylose starch and polyphenols.

Short-chain fatty acids regulate B cells differentiation via FFAR2 to alleviate rheumatoid arthritis

BACKGROUND AND PURPOSE

Short-chain fatty acids (SCFAs) are metabolites of gut microbes involved in the host's inflammatory response and immunity. The aim of this study was to investigate the role of SCFAs in RA and the possible mechanisms.

EXPERIMENTAL APPROACH

Gut microbiota diversity in mice was analysed by 16S rDNA sequencing. SCFAs levels were analysed by gas chromatography mass spectrometry. T cells and B cells were analysed by flow cytometry. Bone damage was analysed by micro-CT and x-ray. Histopathological status was analysed by HE staining. The protein in tissues were analysed by immunohistochemistry and PCR. Mice with CD19⁺ B cells specifically deficient in FFAR2 were used to explore the molecular mechanisms involved.

KEY RESULTS

Levels of acetate, propionate, butyrate, and valerate were decreased in RA patients, and the first three levels correlated positively with the frequency of Bregs in peripheral blood but not with Tregs. Administration of the three SCFAs prior to the onset of collagen-induced arthritis in mice improved arthritic symptoms, increased the Bregs frequency, and decreased transitional B cells and follicular B cells frequency. However, the preceding phenomena could not be observed in mice with CD19⁺ B cells deficient in FFAR2. The effects of the three SCFAs in RA were dependent on FFAR2 while were independent of the other five B cell receptors (FFAR3, GPR109A, PPARγ, Olfr-78, and AhR).

CONCLUSIONS AND IMPLICATIONS

SCFAs regulate B cells differentiation via FFAR2 to alleviate RA. This will provide new insights into the treatment of RA from an immunological and microbiological perspective.

Alterations of gut microbiota-derived metabolites in gestational diabetes mellitus and clinical significance

BACKGROUND

The change in the characteristics of the gut microbiota is linked to gestational diabetes mellitus (GDM). However, whether and how the gut microbiota-derived metabolites change in GDM is uncertain. Here, we aimed to determine associations between the gut microbiota-derived metabolites and GDM.

METHODS

Using targeted metabolomics approaches, 7 types of short-chain fatty acids (SCFAs), 38 types of bile acids (BAs), and 5 types of trimethylamine N-oxide (TMAO), and its derivatives of serum samples were obtained from pregnant women with GDM (n = 24), and healthy pregnant controls (HC, n = 28) were detected to identify the metabolic signature of GDM to investigate the potential biomarkers. Moreover, we assessed the associations between gut microbiota-derived metabolites and clinical parameters.

RESULTS

In our study, the gut microbiota-derived metabolites signatures were significantly different between GDM and HC. Quantitative results showed the levels of isobutyric acid, isovaleric acid, valeric acid, caproic acid, GUDCA, THDCA + TUDCA, and LCA-3S were significantly higher in GDM, but the level of TMAO and its derivatives did not change significantly. Some altered gut microbiota-derived metabolites were significantly correlated with glucose and lipid levels. Receiver-operating characteristic (ROC) analysis of generalized linear models showed that gut microbiota-derived metabolites may be potential biomarkers of GDM.

CONCLUSION

This study highlights gut microbiota-derived metabolites alterations in GDM and correlation of the clinical indicators, which provides a new direction for future studies aiming to novel serum biomarker for early detection or target of drug therapy of GDM.

Immunomodulating Activity of Pleurotus eryngii Mushrooms Following Their In Vitro Fermentation by Human Fecal Microbiota

Recent studies have revealed the crucial role of several edible mushrooms and fungal compounds, mainly polysaccharides, in human health and disease. The investigation of the immunomodulating effects of mushroom polysaccharides, especially β-glucans, and the link between their anticancer and immunomodulatory properties with their possible prebiotic activity on gut micro-organisms has been the subject of intense research over the last decade. We investigated the immunomodulating effects of Pleurotus eryngii mushrooms, selected due to their high β-glucan content, strong lactogenic effect, and potent geno-protective properties, following in vitro fermentation by fecal inocula from healthy elderly volunteers (>60 years old). The immunomodulating properties of the fermentation supernatants (FSs) were initially investigated in U937-derived human macrophages. Gene expression as well as pro- (TNF-α, IL-1β) and anti-inflammatory cytokines (IL-10, IL-1Rα) were assessed and correlated with the fermentation process. The presence of P. eryngii in the fermentation process led to modifications in immune response, as indicated by the altered gene expression and levels of the cytokines examined, a finding consistent for all volunteers. The FSs immunomodulating effect on the volunteers’ peripheral blood mononuclear cells (PBMCs) was verified through the use of cytometry by time of flight (CyTOF) analysis.

Bacterial communities in the gastrointestinal tract segments of helminth-resistant and helminth-susceptible sheep

Background

Helminth parasitism is a world-wide problem in livestock industries, with major impacts on health, welfare and productivity. The role of the gut microbiota in host-helminth interactions in ruminants has been extensively examined and the present study added to this body of knowledge by assessing the effects of resistance and susceptibility to helminth infection in the gastro-intestinal tract (GIT). Australian Sheep Breeding Values (ASBVs) for faecal egg count (FEC) were used to select the 10 highly helminth-susceptible (High-FEC) and 10 highly helminth-resistant (Low-FEC) sheep. FEC status was confirmed during the experiment. Using samples from the faeces and the lumen of the rumen, abomasum, duodenum, jejunum, ileum, caecum, and colon, DNA was extracted and used for 16 rRNA gene amplicon sequencing.

Results

The most frequent genera identified along the GIT were Eubacterium, Oscillibacter, and Ruminococcus. Intersectoral-specialization zones were identified along the GIT, with the duodenum displaying major differences between the High-FEC and Low-FEC animals in values for alpha and beta diversity. After taking all samples into account and adjusting for GIT segment, the High-FEC and Low-FEC sheep differed significantly for four genera Butyrivibrio, Mycoplasma, Lachnoclostridium and Succiniclasticum. In the duodenum, the abundances of Aminipila, Lachnoclostridium and Mogibacterium differed significantly between the High-FEC and Low-FEC sheep. In the ileum, on the other hand, the genus Mycoplasma was significantly depleted in the Low-FEC group.

Conclusions

The gastro-intestinal microbial profile varies widely between helminth-resistant and helminth-susceptible sheep. Each GIT section appears to support a particular bacterial composition leading to inter-sectoral differences among the various microbial communities. The microbial populations were most rich and diverse in the duodenum of helminth-resistant sheep, comprising bacterial genera that generally ferment carbohydrates. This observation suggests that helminth-resistant sheep can reorganize the duodenal microbiome taxa which may restrict the development of parasites.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42523-022-00172-1.

Polysaccharide Regulation of Intestinal Flora: A Viable Approach to Maintaining Normal Cognitive Performance and Treating Depression

The intestinal tract of a healthy body is home to a large variety and number of microorganisms that will affect every aspect of the host’s life. In recent years, polysaccharides have been found to be an important factor affecting intestinal flora. Polysaccharides are widely found in nature and play a key role in the life activities of living organisms. In the intestinal tract of living organisms, polysaccharides have many important functions, such as preventing the imbalance of intestinal flora and maintaining the integrity of the intestinal barrier. Moreover, recent studies suggest that gut microbes can influence brain health through the brain-gut axis. Therefore, maintaining brain health through polysaccharide modulation of gut flora deserves further study. In this review, we outline the mechanisms by which polysaccharides maintain normal intestinal flora structure, as well as improving cognitive function in the brain via the brain-gut axis by virtue of the intestinal flora. We also highlight the important role that gut microbes play in the pathogenesis of depression and the potential for treating depression through the use of polysaccharides to modulate the intestinal flora.

Consumption of Dairy Foods and Cardiovascular Disease: A Systematic Review

Limited consumption of dairy foods and use of low-fat products is recommended for cardiovascular (CV) prevention; however, other features besides fat content modulate their metabolic effects. We analyze updated evidence on the relationship of different dairy products (low/full-fat dairy, milk, cheese, yogurt) with CVD by reviewing meta-analyses of cohort studies and individual prospective cohort studies with CV hard endpoints (CVD/CHD incidence/mortality), together with meta-analyses of randomized controlled trials exploring the effect of dairy on major CV risk factors. The analyses provide evidence that moderate dairy consumption (up to 200 g/day, globally) has no detrimental effects on CV health and that their effect depends more on the food type (cheese, yogurt, milk) than on the fat content. These data expand current knowledge and may inform revision of current guidelines for CVD prevention.

Protective Effects of Companilactobacillus crustorum MN047 against Dextran Sulfate Sodium-Induced Ulcerative Colitis: A Fecal Microbiota Transplantation Study

Gut microbiota dysbiosis could aggravate the development of ulcerative colitis (UC). Companilactobacillus crustorum MN047 (CCMN) is a potential gut microbiota-regulating probiotic that could produce multiple novel bacteriocins. In this study, fecal microbiota transplantation (FMT) was used to verify whether CCMN could alleviate dextran sulfate sodium-induced UC by regulating gut microbiota. Results showed that both CCMN and FMT ameliorated the symptoms of UC, including attenuating the increased disease activity index, shortened colon length, gut barrier damage, and inflammation. Briefly, CCMN and FMT upregulated the expressions of MUCs and tight junctions, downregulated the expressions of proinflammatory cytokines and chemokines, increased fecal short-chain fatty acids, and lowered serum lipopolysaccharides, which were associated with the regulation of gut microbiota (e.g., increased Akkermansia, Blautia, and Ruminococcus levels). These results demonstrated that CCMN could ameliorate UC by modulating gut microbiota and inhibiting the TLR4/NF-κB pathway. Therefore, CCMN could be considered as a potential probiotic supplement for ameliorating UC.

Influenza: Toward understanding the immune response in the young

Annually influenza causes a global epidemic resulting in 290,000 to 650,000 deaths and extracts a massive toll on healthcare and the economy. Infants and children are more susceptible to infection and have more severe symptoms than adults likely mitigated by differences in their innate and adaptive immune responses. While it is unclear the exact mechanisms with which the young combat influenza, it is increasingly understood that their immune responses differ from adults. Specifically, underproduction of IFN-γ and IL-12 by the innate immune system likely hampers viral clearance while upregulation of IL-6 may create excessive damaging inflammation. The infant's adaptive immune system preferentially utilizes the Th-2 response that has been tied to γδ T cells and their production of IL-17, which may be less advantageous than the adult Th-1 response for antiviral immunity. This differential immune response of the young is considered to serve as a unique evolutionary adaptation such that they preferentially respond to infection broadly rather than a pathogen-specific one generated by adults. This unique function of the young immune system is temporally, and possibly mechanistically, tied to the microbiota, as they both develop in coordination early in life. Additional research into the relationship between the developing microbiota and the immune system is needed to develop therapies effective at combating influenza in the youngest and most vulnerable of our population.

Roseburia hominis Increases Intestinal Melatonin Level by Activating p-CREB-AANAT Pathway

Intestinal melatonin exerts diverse biological effects on the body. Our previous research showed that the abundance of the butyrate-producing bacteria, Roseburia, is positively related to the expression of colonic mucosal melatonin. However, the detailed relationship is unclear. Therefore, we aimed to explore whether Roseburia regulates intestinal melatonin and its underlying mechanisms. Male Sprague–Dawley germfree rats were orally administered with or without Roseburia hominis. R. hominis treatment significantly increased the intestinal melatonin level. The concentrations of propionate and butyrate in the intestinal contents were significantly elevated after gavage of R. hominis. Propionate or butyrate treatment increased melatonin, 5-hydroxytryptamine (5-HT), arylalkylamine N-acetyltransferase (AANAT), and phosphorylated cAMP-response element-binding protein (p-CREB) levels. When pretreated with telotristat ethyl, the inhibitor of tryptophan hydroxylase (TPH), or siRNA of Aanat, or 666-15, i.e., an inhibitor of CREB, propionate, or butyrate, could not promote melatonin production in the pheochromocytoma cell line BON-1. Metabolomics analysis showed that propionate and butyrate stimulation regulated levels of some metabolites and some metabolic pathways in BON-1 cell supernatants. In conclusion, propionate and butyrate, i.e., metabolites of R. hominis, can promote intestinal melatonin synthesis by increasing 5-HT levels and promoting p-CREB-mediated Aanat transcription, thereby offering a potential target for ameliorating intestinal diseases.

A polysaccharide from Rosa roxburghii Tratt fruit attenuates high-fat diet-induced intestinal barrier dysfunction and inflammation in mice by modulating the gut microbiota

Obesity-induced colonic inflammation-stimulated colitis is one of the main causes of colorectal cancer. Dietary polysaccharides are considered an effective agent for relieving obesity-induced inflammatory diseases such as diabetes and colitis. In this work, the protective effects of a polysaccharide (RTFP) extracted from Rosa roxburghii Tratt fruit on barrier dysfunction and inflammation were investigated using obesity-induced colitis model mice. RTFP treatment repaired intestinal barrier dysfunction by increasing the expression of tight junction proteins (ZO-1, claudin-1, and occludin) and reducing the levels of inflammatory cytokines, intestinal permeability, and colonic oxidative stress in mice fed a high-fat diet. Most significantly, RTFP decreased gut inflammation and ameliorated the metabolic dysbiosis of intestinal microflora by decreasing the Firmicutes/Bacteroidetes ratio, reducing the levels of serum D-lactic acid and lipopolysaccharides, and inhibiting the TLR4/NF-κB signaling pathway. Furthermore, RTFP significantly increased the abundance of beneficial bacteria (Ruminococcaceae, Muribaculaceae, Akkermansiaceae, etc.) but decreased the abundance of pathogenic bacteria. These findings indicate that RTFP can be used as a natural anti-inflammatory agent to reduce chronic obesity-induced colitis.

The Nutritional Supplement L-Alpha Glycerylphosphorylcholine Promotes Atherosclerosis

L-alpha glycerylphosphorylcholine (GPC), a nutritional supplement, has been demonstrated to improve neurological function. However, a new study suggests that GPC supplementation increases incident stroke risk thus its potential adverse effects warrant further investigation. Here we show that GPC promotes atherosclerosis in hyperlipidemic Apoe-/- mice. GPC can be metabolized to trimethylamine N-oxide, a pro-atherogenic agent, suggesting a potential molecular mechanism underlying the observed atherosclerosis progression. GPC supplementation shifted the gut microbial community structure, characterized by increased abundance of Parabacteroides, Ruminococcus, and Bacteroides and decreased abundance of Akkermansia, Lactobacillus, and Roseburia, as determined by 16S rRNA gene sequencing. These data are consistent with a reduction in fecal and cecal short chain fatty acids in GPC-fed mice. Additionally, we found that GPC supplementation led to an increased relative abundance of choline trimethylamine lyase (cutC)-encoding bacteria via qPCR. Interrogation of host inflammatory signaling showed that GPC supplementation increased expression of the proinflammatory effectors CXCL13 and TIMP-1 and activated NF-κB and MAPK signaling pathways in human coronary artery endothelial cells. Finally, targeted and untargeted metabolomic analysis of murine plasma revealed additional metabolites associated with GPC supplementation and atherosclerosis. In summary, our results show GPC promotes atherosclerosis through multiple mechanisms and that caution should be applied when using GPC as a nutritional supplement.