Microbiota-generated metabolites promote metabolic benefits via gut-brain neural circuits

Deciphering the interplay between pectin structural variability, intestinal bioavailability and gut microbiota metabolism: A review

Pectins are parts of fruits, vegetables and other plant-based foods in the human daily diet. They are resilient to gastric digestion but undergo fermentation primarily in the large intestine, peaking in the cecum. The depolymerization of the pectins induced by the gut microbiota generally facilitates the subsequent fermentation of sugar monomers, during which SCFAs are primarily generated to exert multiple beneficial functions. Given structural heterogeneity of pectins and intricate process of microbial metabolism, it is crucial to elucidate how the multi-scale structure of pectins impacts their gut fermentation behavior. This review delves into distinct structural domains and fine structural characteristics of pectins, describes their degradation mechanism and bioavailability in the gastrointestinal tract, and provides an overview of the associated pectinolytic enzymes, gut microbiota community, and microbial metabolites. Moreover, recent advances are summarized in the relationships between gut fermentability and various structural parameters of pectins, including molecular size, esterification degree, monosaccharides composition and molecular conformation. Furthermore, how the structural complexity of pectins influences the interplay between saccharolytic metabolism and proteolytic metabolism during microbial fermentation is proposed. This work would help to unravel the "pectin structure - gut microbiota - host health" interactions, thereby guiding the design of functional foods targeting specific microorganisms in future personalized diets.

Bile-processed Rhizoma Coptidis alleviates type 2 diabetes mellitus through modulating the gut microbiota and short-chain fatty acid metabolism

BACKGROUND

Bile-Processed Rhizoma Coptidis (BPRC) is a processed products of Rhizoma Coptidis (RC) commonly used to treat type 2 diabetes mellitus (T2DM). However, the synergistic mechanism of its processing remains unknown. Current research indicates that the gut microbiota and its metabolites, such as short-chain fatty acids (SCFAs), are closely associated with the progression of T2DM.

PURPOSE

This study aims to investigate the effects of BPRC on the gut microbiota and its metabolite SCFAs in T2DM rats.

METHODS

T2DM rat model was induced by a high-fat diet (HFD) combined with streptozotocin (STZ), followed by a 4-week treatment with BPRC to observe its therapeutic effects. The impact of BPRC on the gut microbiota was studied through metagenomic sequencing. Quantitative analysis of SCFAs was conducted using GC-MS. Western blot and quantitative real-time PCR (qRT-PCR) were conducted to investigate the potential mechanisms of BPRC.

RESULTS

BPRC significantly improved insulin resistance in T2DM rats, downregulated levels of pancreatic cell apoptosis factors, and upregulated the abundance of Bacteroides uniformis, Bacteroides sp A1C1, Anaerostipes caccae, Alistipes finegoldii and Blautia sp.N6H1-15 in T2DM rats. Additionally, BPRC increased the levels of seven SCFAs in the intestines of T2DM rats. It activated intestinal TGR5, GPR41, GPR43, and GPR109a receptors, collectively upregulating GLP-1 protein expression, and exerted therapeutic effects on T2DM.

CONCLUSION

The results indicate that the synergistic mechanism of BPRC in treating T2DM is associated with modulating the gut microbiota, increasing SCFAs content in the intestines, and regulating intestinal GLP-1 production.

Secretory IgM regulates gut microbiota homeostasis and metabolism

The coating of microbiota by secretory immunoglobulins (sIgs) determines which bacteria colonize the gut and influences bacterial metabolism. Previous work has identified sIgA and sIgT as mediators of gut homeostasis. However, sIgM coats a large proportion of the gut microbiota in humans and teleost fish, thus suggesting a conserved role of sIgM in microbiota homeostasis. Here, to investigate this hypothesis, we used the teleost rainbow trout as a model system. Depletion of IgM from trout resulted in severe microbiota-dependent gut tissue damage, body weight loss, bacterial translocation and gut dysbiosis. IgM depletion led also to alterations in microbiota-derived metabolites, including short-chain fatty acids and essential amino acids. Supporting a protective role for sIgM in the gut, high mortality of IgM-depleted fish occurred in an experimental colitis model as a result of severe systemic bacteraemia and septic shock. Our findings uncover sIgM as a previously unrecognized regulator of microbiota homeostasis and metabolism.

Gut microbiota and ovarian diseases: a new therapeutic perspective

The gut microbiota is a complex community of microorganisms that inhabit the human gastrointestinal tract, helping to maintain the ecological balance of the body's internal and external environments. Disruptions in the composition and diversity of gut microbiota, as well as changes in their metabolic functions, can link to the development and severity of conditions such as premature ovarian insufficiency, polycystic ovary syndrome, and ovarian tumors. This article thoroughly reviews recent research on the connection between gut microbiota and ovarian diseases, providing fresh perspectives on their prevention, pathogenesis, and treatment.

Abdominal Massage Decreases Food Intake and Body Weight in High-Fat Diet-Induced Obese Rats Through Upregulating GPR41/GPR43-PYY/GLP-1 Axis

Background

Abdominal massage has been found to exert an important role in helping people in overcoming obesity. However, the mechanism by which abdominal massage induces weight loss remains largely unclear.

Methods

Healthy male Sprague-Dawley (SD) rats were randomly grouped into standard diet control (15% fat content) group and high-fat diet (HFD, 40% fat content) group. After 6 weeks of high-fat feeding, rats in the HFD group were successfully modeled, and then separated into the HFD group and HFD plus abdominal massage group. Rats in the HFD plus abdominal massage group were then subjected to abdominal massage for 12 continuous days.

Results

Compared to the HFD group, abdominal massage could decrease body weight, food intake and abdominal fat index (AFI) of HFD-fed rats. Meanwhile, compared to the HFD group, abdominal massage obviously attenuated mucosal epithelial damage and reduced inflammatory cell infiltration in colon mucosal tissues of HFD-fed rats. Furthermore, compared to the HFD group, abdominal massage significantly increased GPR42 and GPR43 levels in the colon tissues of HFD-fed rats, and upregulated the production of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) in colon mucosal tissues of HFD-fed rats.

Conclusion

Collectively, abdominal massage could decrease food intake and body weight in HFD-induced obese rats through upregulating GPR41/GPR43-PYY/GLP-1 axis.

Advancements in the study of short-chain fatty acids and their therapeutic effects on atherosclerosis

Atherosclerosis (AS) remains a leading cause of cardiovascular disease and mortality globally. This chronic condition is characterized by inflammation, lipid accumulation, and the deposition of cellular components within arterial walls. Emerging evidence has highlighted the multifaceted therapeutic potential of short-chain fatty acids (SCFAs) in mitigating AS progression. SCFAs have demonstrated anti-inflammatory properties and the ability to regulate immune responses, metabolic pathways, vascular integrity, and intestinal barrier function in animal models of AS. Consequently, SCFAs have garnered significant attention as a promising approach for the prevention and treatment of AS. However, further clinical trials and studies are necessary to fully elucidate the underlying mechanisms and effects of SCFAs. Additionally, different types of SCFAs may exert distinct impacts, necessitating more in-depth investigation into their specific roles and mechanisms. This review provides an overview of the diverse cellular mechanisms contributing to AS formation, as well as a discussion of the significance of SCFAs in AS pathogenesis and their multifaceted therapeutic potential. Nonetheless, additional research is warranted to comprehensively understand and harness the potential of various SCFAs in the context of AS.

Bacillus licheniformis Alleviates Clostridium perfringens-Induced Intestinal Injury in Mice Model by Modulating Inflammation, Apoptosis, and Cecal Microbial-Metabolic Responses

Bacillus licheniformis (B. licheniformis) is a probiotic known for its ability to enhance host resistance against pathogenic infections. This study aimed to evaluate the protective effects and underlying mechanisms of B. licheniformis in a mouse model challenged with Clostridium perfringens (C. perfringens). C57BL/6J mice were pretreated with B. licheniformis for 21 days before oral infection with C. perfringens. The probiotic administration significantly prevented infection-induced weight loss and immune organ enlargement. Serum cytokine analysis revealed that B. licheniformis increased anti-inflammatory IL-4 and IL-10 levels while reducing pro-inflammatory IL-1β, IL-6, and TNF-α levels. Histological analysis showed that B. licheniformis preserved intestinal morphology and inhibited epithelial cell apoptosis. Moreover, the probiotic mitigated the infection-induced decline in volatile fatty acid (VFA) production. 16S rRNA gene sequencing revealed that B. licheniformis reshaped the cecal microbiota, characterized by the increased abundance of Lachnospiraceae_NK4A136_group, Muribaculaceae, and Parabacteroides, and reduced abundance of Alistipes. Untargeted metabolomic profiling identified differential metabolites-including D-glucono-1,5-lactone, D-erythrose 4-phosphate, and D-sedoheptulose 7-phosphate-enriched in the pentose phosphate pathway, suggesting a regulatory role in redox homeostasis and host response. Collectively, these results indicate that B. licheniformis exerts protective effects against C. perfringens infection by modulating inflammation, apoptosis, microbial composition, and metabolic pathways. This work provides new insights into the application of B. licheniformis as a functional microbial feed additive in livestock disease prevention.

Maternal gut microbiota influences immune activation at the maternal-fetal interface affecting pregnancy outcome

Preeclampsia is a leading cause of morbidity and mortality in pregnant women, affecting 5-8% of gestations worldwide. Its development is influenced by maternal immune abnormalities, metabolic disorders, and gut dysbiosis. In this study, we show that gut dysbiosis in pregnant C57BL/6J dams leads to increased fetal resorption, impaired placental development and altered vascularization. These adverse outcomes are associated with key pathological features of preeclampsia, including hypoxia, endoplasmic reticulum (ER) stress and reduction in uterine natural killer (NK) cell numbers. Furthermore, gut dysbiosis significantly perturbs placental carbohydrate metabolism, which impairs NK cell IFN-γ secretion. Notably, glucose supplementation restores placental NK cell function and reduces fetal resorption, suggesting that the observed impairment is reversible and dependent on a lower glycolytic rate. These findings highlight maternal gut microbiota as a key player in carbohydrate metabolism, with a pivotal role in modulating placental immunity and pregnancy outcome. The results provide valuable insights into potential metabolic biomarkers and suggest that targeting the gut microbiota may offer a strategy for preventing preeclampsia.

Propionic acid/FBP1 is involved in polystyrene nanoplastic-induced cardiac injury via the gut-heart axis

BACKGROUND

Micro-/nanoplastics (MNPLs) are widely found in the environment and have toxic effects on various organs and systems. However, the role of the gut-cardiac axis in cardiotoxicity induced by MNPLs has not yet been elucidated through research.

RESULTS

In this study, we examined the effects of 80 nm polystyrene nanoplastics (PS-NPs) on the heart and human cardiomyocytes (AC16) cells. Histopathological examination showed that NPs caused impaired cardiac function and increased myocardial collagen deposition. In view of the potential influence of gut microbiota and its metabolites on cardiac function, we conduct this study to investigate the specific effects they have on cardiac function. Analysis of cecal contents by 16 s ribosomal RNA (rRNA) and short chain fatty acids (SCFAs) revealed that colonic tissue damage, intestinal flora disorder, and reduction of propionic acid induced by PS-MPs were closely related to cardiac function. Further transcriptomic analysis of heart and colon tissues indicated that propionic acid may reduce cardiac function by reducing the expression of fructose-1, 6-biphosphatase 1 (FBP1). The hypothesis was further verified by in vitro intervention experiments with sodium propionate and FBP1 activator (BML-275).

CONCLUSIONS

In summary, our study systematically demonstrated the role of gut-heart axis in NPs-induced cardiac injury, and the specific process was that NPs exposure reduced propionate level, which in turn inhibited FBP1 expression to impair cardiac function. These findings provide new insights into NPs-induced cardiotoxicity and identifie potential therapeutic targets, providing clues for the prevention and treatment of NPs-induced cardiac injury in the future.

Association of gut microbiota with overweight/obesity combined with gestational diabetes mellitus

Introduction. Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy and negatively affects the health of mothers and infants. The aim of this study was to explore the associations between gut microbiota and the risk of GDM amongst overweight/obese women, and the interaction between gut microbiota dysbiosis and overweight/obesity in pregnant women with GDM.Hypothesis/Gap statement. Previous studies revealed that there may be a link between gut microbiota and GDM and obesity, but these studies have not reported the associations between gut microbiota and the risk of GDM amongst overweight/obese women, whilst the interaction between gut microbiota dysbiosis and overweight/obesity in pregnant women with GDM remains unknown.Aim. Based on a prospective cohort study, we explored the composition of gut microbiota in overweight/obese pregnant women and its association with GDM.Methodology.Participants (n=1820) were enrolled from the Pregnancy Metabolic Disease and Adverse Pregnancy Outcome cohort in Guangzhou, China, between 2019 and 2021. The participants' information and faecal samples were collected, and the relative abundance of faecal microbiota was profiled using 16S rRNA V4 region sequencing. Pregnant women were divided into four groups: non- overweight (NOW)/obese without GDM (OB- NGDM), overweight (OW)/OB- NGDM, NOW/obese with GDM (OB- GDM) and OW/OB- GDM. Linear discriminant analysis effect size (LEfSe) analysis, Spearman's correlation analysis and t- test were performed to estimate the association amongst microbiota, pre- pregnancy BMI and oral glucose tolerance test (OGTT) glucose levels.Results. Blautia, Anaerostipes, Synergistes (P<0.001) and Christensenellaceae_R_7_group (P=0.007) were significantly different between NOW/OB-GDM and OW/OB-GDM groups after adjusting for age. Odoribacter, Anaerostipes, Monoglobus, Romboutsia, Oscillospiraceae__UCG-003, Blautia and Dialisterwere significantly correlated with both OGTT 1 h (P<0.001) and 2 h (P<0.05) blood glucose levels, whilst Lactobacillus(P<0.001) were significantly correlated with OGTT 2 h blood glucose levels. Synergistes(P<0.001) were significantly correlated with OGTT fasting glucose levels, and Megasphaera and Odoribacter(P<0.05) were significantly correlated with pre-pregnancy BMI.Conclusions. GDM and OB/OW women was experiencing microbiota dysbiosis, especially the microbial communities related to glucose metabolism.

Metabolic signaling of ceramides through the FPR2 receptor inhibits adipocyte thermogenesis

Ceramides play a central role in human health and disease, yet their role as systemic signaling molecules remain poorly understood. In this work, we identify formyl peptide receptor 2 (FPR2) as a membrane receptor that specifically binds long-chain ceramides (C14 to C20). In brown and beige adipocytes, C16:0 ceramide binding to FPR2 inhibits thermogenesis through Gi cyclic adenosine monophosphate signaling pathways, an effect that is reversed in the absence of FPR2. We present three cryo-electron microscopy structures of FPR2 in complex with Gi trimers bound to C16:0, C18:0, and C20:0 ceramides. The hydrophobic tails are deeply embedded in the orthosteric ligand pocket, which has a limited amount of plasticity. Modification of the ceramide binding motif in closely related receptors, such as FPR1 or FPR3, converts them from inactive to active ceramide receptors. Our findings provide a structural basis for adipocyte thermogenesis mediated by FPR2.

Interactions between the intestinal microbiota and drug metabolism - Clinical implications and future opportunities

The importance of the intestinal microbita in a multitude of physiological processes is well-evidenced. These include metabolism of nutrients and xenobiotics, biosynthesis of vitamin K and vitamin B12, immunomodulation, maintenance of the gut mucosal barrier integrity and protection against some pathogens. Interindividual differences in the intestinal microbiota composition have impacts on health. The bioavailability and activity of some pharmaceuticals are heavily influenced by interindividual variability in metabolism, which has a genetic basis. This variability, primarily occurring in the liver but also in the intestine, has been studied extensively. Despite the advancement of this field - pharmacogenetics - its integration into clinical practice remains limited for reasons discussed herein. This highlights the even greater challenge of applying emerging knowledge on variability in the gut microbiota to drug therapy. However, ignoring these opportunities would be a mistake. While clinical applications of microbiota-guided drug therapy are currently absent and the ideas in this article are largely theoretical, research is uncovering that in cases where a substantial portion of a drug or its metabolites reaches the colon, or where drugs are formulated for colonic delivery, the gut microbiota can significantly affect drug metabolism and activity. Greater focus should be placed on research into how interindividual variability in the intestinal microbiome can modify pharmaceutical bioavailability and activity. This article is deliberately speculative and exploratory but proposes that, though there are still no clinical examples of microbiome-guided drug therapy, these interactions could afford opportunities for improvements in personalised medicine and also for drug design.

Characterization of Fecal Microbial Communities in Patients With Type 2 Diabetes Mellitus Combined With Helicobacter pylori Infection

BACKGROUND

Helicobacter pylori (H. pylori) infection has the capacity to alter the gut microbiota composition. There is a significant correlation between H. pylori infection and type 2 diabetes mellitus (T2DM). Further research is necessary to explore whether gut microbiota plays a role in the relationship between H. pylori and T2DM.

METHOD

Fecal samples were obtained from 44 patients with T2DM, including 20 who tested positive for H. pylori and 24 who tested negative. Intestinal microbiota composition was analyzed via 16S rRNA V3-V4 amplicon sequencing. Differences in microbial distribution and significant microbial biomarkers were identified between H. pylori positive and negative groups. A Spearman correlation analysis assessed the relationship between intestinal microbiota and glycemic parameters. Additionally, PICRUSt2 was used to predict intestinal bacterial functions.

RESULTS

Results indicate that in H. pylori (+) T2DM patients, HbA1c levels were significantly higher (8.9% vs. 8.1%, p = 0.021), while both the C-peptide peak (3.70 vs. 5.98 ng/mL, p = 0.040) and fasting C-peptide levels (1.42 vs. 2.31 ng/mL, p = 0.008) were significantly lower compared to H. pylori (-) T2DM groups. A total of 11 colonic phyla and 100 genera were identified in all fecal samples. In groups positive for H. pylori, there was a significant enrichment of the phylum Proteobacteria, while the genera Lactobacillus, Butyricimonas, and Akkermansia were significantly reduced (all p < 0.05). Correlation analysis showed that the abundance of the genera Butyricimonas (p = 0.01) and Akkermansia (p = 0.048) were negatively correlated with fasting plasma glucose. KEGG pathway analysis indicated a significant enrichment of methylmalonyl-CoA mutase and succinyl-CoA in H. pylori-infected T2DM patients.

CONCLUSIONS

This study suggests that T2DM patients with H. pylori infection exhibit more impaired pancreatic islet function potentially due to H. pylori-induced alterations in the gut microbiota.

Gender and age-related variations in rumen fermentation and microbiota of Qinchuan cattle

OBJECTIVE

Our study aimed to investigate the gender and age-related variations in rumen fermentation, serum metabolites, and microbiota in Qinchuan cattle.

METHODS

A total of 38 Qinchuan beef cattle were selected and maintained on a uniform diet for three months. Rumen fluid and blood samples were collected to determine rumen fermentation, serum metabolites, and microbial 16S rRNA sequencing.

RESULTS

The results revealed that the concentration of rumen butyrate in female Qinchuan cattle was significantly higher than in males (p<0.05). Isobutyrate, butyrate, and isovalerate exhibited significant age-related differences. Females exhibited lower serum glucose (GLU) and higher triglycerides (TG), nonesterifiedfatty acid (NEFA) levels compared to males (p<0.05). Serum albumin (ALB) and urea (UA) levels increased with age (p<0.05). Furthermore, the alpha diversity of rumen bacteria improved with age (p<0.05), with no gender differences observed. Males had higher relative abundances of Bacteroidota, Verrucomicrobiota, and Cyanobacteria, while females had higher Firmicutes and Desulfobacterota (p<0.05). The cellulose-degrading genus Ruminococcus and propionateproducing genus Succiniclasticum were more abundant in females, whereas the antiinflammatory genus Lachnospiraceae_NK4A136_group and the hemicellulose-degrading genus Prevotella were more abundant in males (p<0.05). Age-related differences in bacteria were found in Pseudobutyrivibrio and several members of the Lachnospiraceae. Functional prediction indicated that "Amino acid metabolism" and "Lipid metabolism" were mainly enriched in females, whereas "Carbohydrate metabolism" and "Glycan biosynthesis and metabolism" were enriched in males (p<0.05). RDA analysis highlighted butyrate as a key factor influencing the rumen bacterial community. NK4A214_group and Ruminococcus were positively correlated with butyrate, while Prevotella and Pseudobutyrivibrio were negatively correlated with butyrate (p<0.05).

CONCLUSION

We observed a significant improvement in the diversity and stability of rumen microbiota as age increased. Ruminococcus, NK4A214_group, and Prevotella were likely contributors to variations in energy utilization and fat deposition between male and female Qinchuan cattle.

Inflammatory bowel disease and neuropsychiatric disorders: Mechanisms and emerging therapeutics targeting the microbiota-gut-brain axis

Crohn's disease (CD) and ulcerative colitis (UC) are the two major entities of inflammatory bowel disease (IBD). These disorders are known for their relapsing disease course and severe gastrointestinal symptoms including pain, diarrhoea and bloody stool. Accumulating evidence suggests that IBD is not only restricted to the gastrointestinal tract and that disease processes are able to reach distant organs including the brain. In fact, up to 35 % of IBD patients also suffer from neuropsychiatric disorders such as generalized anxiety disorder and major depressive disorder. Emerging research in this area indicates that in many cases these neuropsychiatric disorders are a secondary condition as a consequence of the disturbed communication between the gut and the brain via the microbiota-gut-brain axis. In this review, we summarise the current knowledge on IBD-associated neuropsychiatric disorders. We examine the role of different pathways of the microbiota-gut-brain axis in the development of CNS disorders highlighting altered neural, immunological, humoral and microbial communication. Finally, we discuss emerging therapies targeting the microbiota-gut-brain axis to alleviate IBD and neuropsychiatric symptoms including faecal microbiota transplantation, psychobiotics, microbial metabolites and vagus nerve stimulation.

An integrated fecal microbiome and metabolomics in type 2 diabetes mellitus rats reveal mechanism of action of Moringa oleifera Lamarck seeds polysaccharides to alleviate diabetes

Moringa oleifera Lamarck seeds (MOS) have been traditionally used in folk medicine and documented for their potential to alleviate type 2 diabetes symptoms, but the potential mechanisms are still unknown. The purpose of this article is to investigate the effects of MSAP (alkali-extracted polysaccharide from MOS) on diabetic rats by assessing its impact on the gut microbiome, diabetes-related biochemical markers, and fecal metabolomics. The results demonstrated that the fasting blood glucose, glucose tolerance, insulin resistance, insulin level and lipopolysaccharides (LPS) level in the rats treated with MSAP were all improved. Specifically, MSAP was found to modulate the composition and diversity of the gut microbiota, increasing the ratio of Firmicutes/Bacteroidetes, which enhanced the quantity of probiotic Lactobacillus and butyrate-producing bacteria, such as Roseburia, thereby reinforcing the intestinal epithelial barrier. Furthermore, fecal metabolomics indicates that MSAP actively regulates pathways closely associated with diabetes, including sphingolipid metabolism, amino acid synthesis and catabolism, retrograde endogenous cannabinoid signaling, and the modulation of TRP channels by inflammatory mediators. By integrating microbiome and metabolomics data, this study elucidated the mechanisms through which MSAP alleviates diabetes. In conclusion, the findings suggest that polysaccharides from MOS hold potential as a medicinal and edible homologous food for diabetes management.

Uncovering the heterogeneity of the gut microbial taxa associated with the contents of different fatty acids in muscle with cecum luminal content and fecal samples from two pig populations

Fatty acids in pork are involved in cellular physiological functions and related to meat nutrition, tenderness, and flavor. Increasing evidences have suggested that short-chain fatty acids produced by the gut microbiota may affect host metabolism and energy utilization. However, the association between gut microbiota and long-chain fatty acids (LCFAs) in pork has been largely unknown. In this study, the microbial compositions of 243 cecum content samples from Erhualian pigs and 235 fecal samples from Bamaxiang pigs were determined by high throughput 16S rRNA gene sequencing. The contents of 12 LCFAs in longissimus dorsi (LD) muscle were also determined for all experimental pigs of both pig populations. We systematically evaluated the contribution of gut microbiota to the variations of muscle fatty acid contents from the α-diversity of gut microbiota, co-abundance groups (CAGs) of Amplicon Sequence Variants (ASVs), and fatty acid-associated bacterial taxa. We identified hundred ASVs and > 40 bacterial taxa that were significantly associated with muscle fatty acid contents in two pig populations. Different numbers and bacterial taxa associated with the content of specific LCFAs in muscle were detected between cecum luminal content and fecal samples, suggesting the heterogeneity of the specific LCFA-associated bacterial taxa between two gut locations. We uncovered some interesting associations between bacterial taxa and muscle fatty acid contents. The strongest association was observed between the ASV annotated to Akkermansia and the n-6/n-3 polyunsaturated fatty acid ratio (p = 6.45E-04, Z = -9.65). The gut microbiota could explain 1.47-4.62% variation of muscle contents of twelve fatty acids. The functional prediction analysis identified that the KEGG pathways related to the metabolisms of carbohydrate and lipids, and to fat digestion and absorption were positively associated with the contents of muscle fatty acids. However, adipocytokine signaling pathway and thermogenesis were negatively associated with muscle fatty acid contents. The results from this study provided the basic knowledge for improving the muscle fatty acid contents by regulating the gut microbiome.

Gut Microbiota and Metabolic Dysregulation in Elderly Diabetic Patients: Is There a Gender-Specific Effect

Background/Objectives: The aim of this study was to qualitatively and quantitatively assess the bacterial domain of the gut microbiome in elderly patients with type 2 diabetes (T2D), with a focus on sex differences, glycemic control, and lipid disorders. Methods: This study included 60 older adults with T2D (38 women and 22 men) treated with metformin or a combination of metformin and insulin. The gut microbiota was profiled using 16S rRNA gene sequencing. Statistical analyses, including correlation analysis and multiple regression, were performed to identify the associations between microbial taxa, sex, and metabolic parameters. Results: No statistically significant differences in alpha or beta diversity were observed between the sexes. Multiple regression analysis indicated a positive relationship between Tenericutes and HbA1c in male participants (β = 2.22931, CI [0.75, 3.70], R = 0.67; R2 = 0.36; unadjusted p = 0.0052; adjusted p = 0.0496). In female participants, G0' (β = -2.24107, CI [-3.19, -1.30], R = 0.78; R2 = 0.58; unadjusted p = 0.00003; adjusted p = 0.0005) and HbA1c (β = -1.86670, CI [-2.61, -1.12], R = 0.78; R2 = 0.58; unadjusted p = 0.00001; adjusted p = 0.0003) correlated negatively with Verrucomicrobia as well G0' (β = -1.90427, CI [-2.95, -0.85], R = 0.46; R2 = 0.17; unadjusted p = 0.0008; adjusted p = 0.007) and HbA1c (β = -1.69561, CI [-2.52, -0.87], R = 0.46; R2 = 0.17; unadjusted p = 0.0002; adjusted p = 0.002) correlated negatively with OD1 bacteria, known as Parcubacteria. Conclusions: In this elderly population with type 2 diabetes, biological sex did not significantly affect the gut microbiota diversity. However, several exploratory associations between microbial taxa and metabolic parameters differed between men and women, suggesting that sex may influence specific aspects of microbiota-metabolism interactions. These preliminary findings underscore the importance of considering both age- and sex-related factors when investigating the gut microbiome in the context of type 2 diabetes.

IUPHAR Review: Microbiota-Gut-Brain Axis and its role in Neuropsychiatric Disorders

The human gut microbiome, composed of a vast array of microorganisms that have co-evolved with humans, is crucial for the development and function of brain systems. Research has consistently shown bidirectional communication between the gut and the brain through neuronal, endocrine, and immunological, and chemical pathways. Recent neuroscience studies have linked changes in the microbiome and microbial metabolites to various neuropsychiatric disorders such as autism, depression, anxiety, schizophrenia, eating disorders, and neurocognitive disorders. Novel metagenome-wide association studies have confirmed these microbiome variations in large samples and expanded our understanding of the interactions between human genes and the gut microbiome. The causal relationship between gut microbiota and neuropsychiatric disorders is being elucidated through the establishment of large cohort studies incorporating microbiome data and advanced statistical techniques. Ongoing animal and human studies focused on the microbiota-gut-brain axis are promising for developing new prevention and treatment strategies for neuropsychiatric conditions. The scope of these studies has broadened from microbiome-modulating therapies including prebiotics, probiotics, synbiotics and postbiotics to more extensive approaches such as fecal microbiota transplantation. Recent systematic reviews and meta-analyses have strengthened the evidence base for these innovative treatments. Despite extensive research over the past decade, many intriguing aspects still need to be elucidated regarding the role and therapeutic interventions of the microbiota-gut-brain axis in neuropsychiatric disorders.

Microbiota-gut-brain-axis: a new target of acupuncture therapy for post-stroke cognitive impairment

Stroke-induced cognitive impairment is a common complication and an important risk factor for disability. Prevention and treatment of secondary stroke injuries are crucial. Modern research has found that the gut microenvironment can directly or indirectly affect neurological function and cerebral ischemic outcomes, and their crosstalk is achieved through the microbiota-gut-brain-axis (MGBA). Acupuncture, as a promising non-drug treatment, has been recommended for improving post-stroke cognitive impairment (PSCI). However, in recent years, few studies have systematically analyzed the potential mechanisms in this field, and whether acupuncture can improve PSCI through the MGBA remains to be explored. This review comprehensively summarizes literature and shows that, acupuncture, as an adjuvant therapy can play a potential important role in the treatment of PSCI by regulating the microbiota-gut-brain-axis. Acupuncture can repair intestinal epithelial barrier, regulate gut microbiota and serum metabolites, alleviate gut inflammation and neuroinflammation, and regulating HPA axis function, etc. From the studies we have included, the evidence for its effectiveness remains limited, these results should be interpreted with caution due to the low quality of evidence. Future high-quality clinical and experimental studies are needed. This review also discussed the development prospects of acupuncture in improving PSCI via the MGBA, such as genomics, personalized therapy, establishment of standards, and combination therapy, etc. providing new research ideas and scientific and reliable evidence for the application of acupuncture in PSCI.

Butyrate: a key mediator of gut-brain communication in Alzheimer's disease

Alzheimer's disease (AD), a prevalent neurodegenerative disorder, represents a significant global health challenge, characterized by cognitive decline and neuroinflammation. Recent investigations have highlighted the critical role of the gut-brain axis in the pathogenesis of AD, particularly focusing on the influence of short-chain fatty acids (SCFAs), metabolites produced by the gut microbiota through the fermentation of dietary fiber. Among SCFAs, butyrate has emerged as a crucial mediator, positively impacting various pathological processes associated with AD, including epigenetic regulation, neuroinflammation modulation, maintenance of the blood-brain barrier (BBB), enhanced intestinal integrity, regulation of brain metabolism, and interference with amyloid protein formation as well as tau protein hyperphosphorylation. Furthermore, distinctions in butyrate profile and microbial communities have been observed between AD patients and healthy individuals, underscoring the importance of gut microbiota in AD progression. This review summarizes the current understanding of the many functions of butyrate in reducing the consequences of AD and emphasizes the possibility of addressing the gut microbiota as a therapeutic approach to managing AD.

Berberine and health outcomes: an overview of systematic reviews

BACKGROUND

Berberine is an isoquinoline alkaloid isolated from Chinese herb coptis chinensis and other berberis plants which can be used to treat a wide range of chronic diseases. However, the current research evidence on the therapeutic effects of berberine has not been summarized. We aimed to synthesize the current evidence on the systematic review (SRs) of berberine for the treatment of diverse conditions.

METHODS

A comprehensive search of the Cochrane Library, PubMed, EMBASE, Web of Science, CNKI, Wanfang, VIP, and SinoMed was performed from the database inception to April 11, 2024. SRs on berberine were included and evaluated. The methodological quality and the reporting quality of each SR were assessed using the AMSTAR-2 tool and PRISMA checklist, respectively. The quality of evidence was appraised based on the GRADE.

RESULTS

Fifty-four SRs were included and analyzed. Overall, associations were found between berberine and 70 health outcomes concerned with 9 diseases. Berberine has improved most outcomes of these diseases: 78% (25/32) cardiovascular disease outcomes, 92.59% (25/27) type 2 diabetes mellitus outcomes, 94.74% (18/19) gastrointestinal disorders outcomes, 72.22% (13/18) polycystic ovary syndrome (PCOS) outcomes, 86.67% (13/15) non-alcoholic fatty liver disease (NAFLD) outcomes, 92.31% (12/13) schizophrenia outcomes, 90.91% (10/11) metabolic syndrome outcomes, 57.14% (4/7) obesity outcomes, and 100.00% (6/6) dyslipidemia outcomes. There was a high overlap of primary studies (CCA > 15%) in the SRs of PCOS, NAFLD, obesity, and schizophrenia. Only one SR was rated as high quality while eight SRs were rated as low quality and forty-five SRs as very low quality according to AMSTAR-2. Regarding the reporting quality, Item 14, 15, 21, and 22 were poorly reported for the included SRs in terms of PRSMA assessment. For GRADE, eight outcomes were rated as high quality evidence, twenty-two outcomes were rated as moderate quality, and 110 outcomes were rated as low quality.

CONCLUSION

Current evidence suggests that berberine has beneficial effects on a range of health outcomes for people with chronic diseases. Specifically, berberine significantly improves type 2 diabetes, gastrointestinal disorders, schizophrenia, metabolic syndrome, and dyslipidemia outcomes. However, caution is needed considering the shortcomings in the quality of the relevant system reviews included.

A Comparison Between High- and Low-Performing Lambs and Their Impact on the Meat Quality and Development Level Using a Multi-Omics Analysis of Rumen Microbe-Muscle-Liver Interactions

Through an integrated multi-omics analysis of rumen microbial communities, muscle transcriptomes, metabolic profiles, and liver metabolic profiles, this study systematically compared high- and low-performing lambs to elucidate their divergent effects on meat quality attributes and growth development. A total of 100 male lambs with similar birth weight (3.07 ± 0.06 kg) were selected within 72 h. All test lambs were synchronized weaning at 45 days of age and uniformly fed the same diet (total mixed ration) in the same pen until 180 days of age, with ad libitum access to food and water throughout this period. Subsequently, the eight lambs with the highest (HADG) and lowest (LADG) average daily gains were slaughtered for performance evaluation and multi-omics analysis. This study found that HADG lambs increased body weight, muscle fiber diameter, eye muscle area, improved amino acid (histidine, arginine, valine, isoleucine, essential amino acid/total amino acid, and essential amino acid/nonessential amino acid), and fatty acid (linoleic acid, behenic acid, and arachidonic acid) composition enhanced rumen enzymes (pepsase, lipase, xylanase, amylase, and carboxymethyl cellulose) and promoted efficient fermentation (p < 0.05). Analysis of microbial populations indicated a notable increase in Prevotella levels within the rumen of HADG lambs. Furthermore, the rumen markers Schwartzia and Streptococcus exhibited significant correlations with differential meat quality traits. Analysis of the muscle transcriptome indicated a significant correlation between the turquoise module and host phenotypes, particularly body weight. Additionally, muscle metabolism is primarily concentrated within the black module; however, it exhibits a significant correlation with the host body phenotype in the yellow module (p < 0.05). Moreover, liver metabolites, rumen microbes, host phenotype, and muscle transcripts were significantly correlated (p < 0.05). In conclusion, the interactions among rumen microbes, muscle, and liver in lambs promote rumen fermentation, which in turn regulate muscle transcriptional activity and modify metabolic profiles in both the liver and muscle. Moreover, PCK1, SPP1, FGF7, NR4A1, DUSP5, GADD45B, etc., can be candidate genes for muscle growth and development. This finding provides a theoretical basis for further exploiting the production potential of Hu lambs.

Research progress of the intestinal axis in autologous arteriovenous fistula stenosis in maintenance hemodialysis patients

The number of the patients treated with maintenance hemodialysis (HD) is increasing due to the increasing incidence of end stage renal disease (ESRD). Autologous arteriovenous fistula (AVF) is the preferable modality for long-term vascular access during HD. AVF stenosis is the main cause of AVF dysfunction in HD patients, but its mechanism has not been fully elucidated. Patients with ESRD often have various related complications due to intestinal microbiota disorders and their metabolites, and the intestinal axis reveals various metabolic disorders in patients with chronic kidney disease. This paper analyzes the correlation between intestinal axis abnormalities and AVF stenosis in patients with CKD through three axes: "gut-liver axis," "gut-brain axis," and "gut-spleen axis," to provide clinical significance for elucidating the mechanism of AVF stenosis and for the prevention and treatment of AVF stenosis.

Intestinal dysbiosis leads to the reduction in neurochemical production in Parkinson's disease (PD)

Parkinson's Disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms, with emerging research suggesting a critical link between intestinal dysbiosis and PD progression. This review explores the pathophysiological mechanisms underlying PD, such as alpha-synuclein aggregation, mitochondrial dysfunction, neuroinflammation, and oxidative stress, while focusing on the impact of gut dysbiosis on intestinal barrier function and its role in reduced neurochemical production. The clinical features of PD, including dopamine, serotonin, and GABA deficiencies, are examined, with a focus on how dysbiosis contributes to neurotransmitter depletion. Current treatments of PD, such as levodopa and dopamine agonists, are discussed alongside gut health therapies such as probiotics, prebiotics, and Fecal Microbiota Transplantation (FMT). Future therapeutic directions, including synbiotics, engineered microbes, phage therapy, and the integration of machine learning (ML) and artificial intelligence (AI), are explored. The chapter also considers preventive strategies, such as lifestyle adjustments and early gut health monitoring using modern diagnostic tools and biosensors. Furthermore, a strong need for continued research into the gut-brain axis (GBA) to develop more effective, gut-targeted therapies for managing PD is discussed.

Gut Microbiota in Heart Failure-The Role of Inflammation

Heart failure (HF) has become an immense health concern affecting almost 1-2% of the population globally. It is a complex syndrome characterized by activation of the sympathetic nervous system and the Renin-Angiotensin-Aldosterone (RAAS) axis as well as endothelial dysfunction, oxidative stress, and inflammation. The recent literature points towards the interaction between the intestinal flora and the heart, also called the gut-heart axis. The human gastrointestinal tract is naturally inhabited by various microbes, which are distinct for each patient, regulating the functions of many organs. Alterations of the gut microbiome, a process called dysbiosis, may result in systemic diseases and have been associated with heart failure through inflammatory and autoimmune mechanisms. The disorder of intestinal permeability favors the translocation of microbes and many metabolites capable of inducing inflammation, thus further contributing to the deterioration of normal cardiac function. Besides diet modifications and exercise training, many studies have revealed possible gut microbiota targeted treatments for managing heart failure. The aim of this review is to demonstrate the impact of the inflammatory environment induced by the gut microbiome and its metabolites on heart failure and the elucidation of these novel therapeutic approaches.

Beyond the Gut: Unveiling Butyrate's Global Health Impact Through Gut Health and Dysbiosis-Related Conditions: A Narrative Review

Short-chain fatty acids (SCFAs), mainly produced by gut microbiota through the fermentation process of dietary fibers and proteins, are crucial to human health, with butyrate, a famous four-carbon SCFA, standing out for its inevitably regulatory impact on both gut and immune functions. Within this narrative review, the vital physiological functions of SCFAs were examined, with emphasis on butyrate's role as an energy source for colonocytes and its ability to enhance the gut barrier while exhibiting anti-inflammatory effects. Knowledge of butyrate synthesis, primarily generated by Firmicutes bacteria, can be influenced by diets with specifically high contents of resistant starches and fiber. Butyrate can inhibit histone deacetylase, modulate gene expression, influence immune functionality, and regulate tight junction integrity, supporting the idea of its role in gut barrier preservation. Butyrate possesses systemic anti-inflammatory properties, particularly, its capacity to reduce pro-inflammatory cytokines and maintain immune homeostasis, highlighting its therapeutic potential in managing dysbiosis and inflammatory diseases. Although butyrate absorption into circulation is typically minimal, its broader health implications are substantial, especially regarding obesity and type 2 diabetes through its influence on metabolic regulation and inflammation. Furthermore, this narrative review thoroughly examines butyrate's growing recognition as a modulator of neurological health via its interaction with the gut-brain axis. Additionally, butyrate's neuroprotective effects are mediated through activation of specific G-protein-coupled receptors, such as FFAR3 and GPR109a, and inhibition of histone deacetylases (HDACs). Research indicates that butyrate can alleviate neurological disorders, including Alzheimer's, Parkinson's, autism spectrum disorder, and Huntington's disease, by reducing neuroinflammation, enhancing neurotransmitter modulation, and improving histone acetylation. This focus will help unlock its full therapeutic potential for metabolic and neurological health, rather than exclusively on its well-known benefits for gut health, as these are often interconnected.

Role of short-chain fatty acids in non-alcoholic fatty liver disease and potential therapeutic targets

Non-alcoholic fatty liver disease (NAFLD) is increasing worldwide and has become the greatest potential risk for cirrhosis and hepatocellular carcinoma. The metabolites produced by the gut microbiota act as signal molecules that mediate the interaction between microorganisms and the host and have biphasic effects on human health. The gut microbiota and its metabolites, short-chain fatty acids (SCFAs), have been discovered to ameliorate many prevalent liver diseases, including NAFLD. Currently, SCFAs have attracted widespread attention as potential therapeutic targets for NAFLD, but the mechanism of action has not been fully elucidated. This article summarizes the mechanisms of short-chain fatty acids of gut microbiota metabolites to regulate the metabolism of glucose and lipid, maintain the intestinal barrier, alleviate the inflammatory response, and improve the oxidative stress to improve NAFLD, in order to provide a reference for clinical application.

Butyric acid-based products, alone or in combination with hydroxy-selenomethionine, improve performance of laying hens in post-peak period by modulating their antioxidant, metabolic and immune status

This study aimed to evaluate the effects of butyrate, butyric glycerides (BG) and their combination with sodium selenite (SeNa) or hydroxy-selenomethionine (OH-SeMet) on the performance and egg quality of the laying hens in post-peak period as well as the potential mechanism. A total of 900 45-week-old Hy-Line brown laying hens were randomly allocated to 5 treatment groups (n = 10 replicates/diet, 18 hens/replicate). The hens were fed the basal diet supplemented with 0.3 mg/kg selenium from SeNa (Control), Control plus 240 mg/kg butyric acid from coated butyrate (CB), Control plus 240 mg/kg butyric acid from butyric glycerides, basal diet supplemented with 0.3 mg/kg selenium from OH-SeMet plus coated butyrate (CB+OH-SeMet) or butyric glycerides (BG+OH-SeMet), respectively, for 20 weeks. Serum, liver, isthmus, uterus, and jejunum were collected at the end of the trial for biochemistry, histology, redox status, and gene expression analysis. Compared with Control, diets supplemented with BG, CB+OH-SeMet and BG+OH-SeMet increased (p < 0.05) the average egg weight (0.6-2.2 %), while only BG+OH-SeMet increased (p < 0.05) the total egg weight (7.1 %) and egg-laying rate (4.6 %) and decreased (p < 0.05) the feed/egg ratio (5.0 %) throughout the whole experiment. Furthermore, BG+OH-SeMet reduced (p < 0.05) the content of IL-6 and alanine aminotransferase (15.4-32.5 %), while elevated (p < 0.05) the content of IgA, IgY, IgM and total protein (18.7-26.8 %) in the serum in comparison to the Control. Notably, dietary supplementation of BG+OH-SeMet performed more effective antioxidant capacity in decreasing (p < 0.05) malondialdehyde (16.4-27.9 %) content and increasing (p < 0.05) the activity of total antioxidant capacity and glutathione peroxidase (17.6-36.3 %) in various tissues. Further experiment revealed that dietary BG+OH-SeMet regulated the lipid metabolism by increasing (p < 0.05) the expression of Carnitine palmitoyltransferase 1A (CPT1A) and Lipoprotein lipase (LPL) in liver. In conclusion, diets supplemented with BG and OH-SeMet could improve the laying performance via the enhancement of antioxidant capacity and regulation of lipid metabolism.

Probiotics as a possible novel therapeutic option to mitigate perioperative neurocognitive disorders: A review exploring the latest research findings

Perioperative neurocognitive disorders (PND) refer to a constellation of symptoms that primarily affect the elderly and typically manifest as common complications after exposure to surgery and anesthesia. PND is associated with high morbidity, mortality, and progression to neurodegenerative diseases, thus exerting significant financial strains on families as well as the healthcare system. Given that an ageing global population is an inevitable trend and, with the latest advances in the healthcare system, an ever-growing number of elderly people present for surgery and anesthesia, PND is of prominent concern. The two-way communication between the intestinal flora and the brain, also known as the microbiota-gut-brain axis, plays an important role in central nervous system development, and multiple studies have highlighted the influence exerted by gut microbiome in both health and disease. Pertinent studies have corroborated the fact that anesthesia and surgery disrupt the harmony of the gut ecology, which sets off a cascade of events that initiate neuroinflammation, eventually leading to PND. Probiotics, which are live microorganisms that promote the host's health, have been shown as a viable option to restore or minimise the disruption of gut flora. Evidence exists that probiotics exhibit immunomodulatory and anti-inflammatory benefits. Given the effectiveness of probiotics in reducing neuroinflammation, research has also focused on their impact on the development of PND. This review aims to compile the data from relevant clinical trials focusing on the influence of probiotics on PND to determine whether the derived findings might be applied for the prevention and treatment of PND.

Impacts of non-nutritive sweeteners on the human microbiome

Replacing sugar with non-nutritive sweeteners (NNS) is a common dietary strategy for reducing the caloric content and glycemic index of foods and beverages. However, the efficacy of this strategy in preventing and managing metabolic syndrome and its associated comorbidities remains uncertain. Human cohort studies suggest that NNS contribute to, rather than prevent, metabolic syndrome, whereas randomized controlled trials yield heterogeneous outcomes, ranging from beneficial to detrimental impacts on cardiometabolic health. The World Health Organization recently issued a conditional recommendation against using NNS, citing the need for additional evidence causally linking sweeteners to health effects. One proposed mechanism through which NNS induce metabolic derangements is through disruption of the gut microbiome, a link strongly supported by evidence in preclinical models. This review summarizes the evidence for similar effects in interventional and observational trials in humans. The limited available data highlight heterogeneity between trials, as some, but not all, find NNS consumption associated with microbiome modulation as well as metabolic effects independent of sweetener type. In other trials, the lack of microbiome changes coincides with the absence of metabolic effects. We discuss the hypothesis that the impacts of NNS on health are personalized and microbiome dependent. Thus, a precision nutrition approach may help resolve the conflicting reports regarding NNS impacts on the microbiome and health. This review also discusses additional factors contributing to study heterogeneity that should be addressed in future clinical trials to clarify the relationship between NNS, the microbiome, and health to better inform dietary guidelines and public health policies.

Limosilactobacillus reuteri promotes the expression and secretion of enteroendocrine- and enterocyte-derived hormones

Intestinal microbes can beneficially impact host physiology, prompting investigations into the therapeutic usage of such microbes in a range of diseases. For example, human intestinal microbe Limosilactobacillus reuteri strains ATCC PTA 6475 and DSM 17938 are being considered for use for intestinal ailments, including colic, infection, and inflammation, as well as for non-intestinal ailments, including osteoporosis, wound healing, and autism spectrum disorder. While many of their beneficial properties are attributed to suppressing inflammatory responses, we postulated that L. reuteri may also regulate intestinal hormones to affect physiology within and outside of the gut. To determine if L. reuteri secreted factors impact the secretion of enteric hormones, we treated an engineered jejunal organoid line, NGN3-HIO, which can be induced to be enriched in enteroendocrine cells, with L. reuteri 6475 or 17938 conditioned medium and performed transcriptomics. Our data suggest that these L. reuteri strains affect the transcription of many gut hormones, including vasopressin and luteinizing hormone subunit beta, which have not been previously recognized as produced in the gut epithelium. Moreover, we find that these hormones appear to be produced in enterocytes, in contrast to canonical gut hormones produced in enteroendocrine cells. Finally, we show that L. reuteri conditioned media promote the secretion of enteric hormones, including serotonin, GIP, PYY, vasopressin, and luteinizing hormone subunit beta, and identify by metabolomics metabolites potentially mediating these effects on hormones. These results support L. reuteri affecting host physiology through intestinal hormone secretion, thereby expanding our understanding of the mechanistic actions of this microbe.

The role of polysaccharides in immune regulation through gut microbiota: mechanisms and implications

Polysaccharides, as complex carbohydrates, play a pivotal role in immune modulation and interactions with the gut microbiota. The diverse array of dietary polysaccharides influences gut microbial ecology, impacting immune responses, metabolism, and overall well-being. Despite their recognized benefits, there is limited understanding of the precise mechanisms by which polysaccharides modulate the immune system through the gut microbiota. A comprehensive search of Web of Science, PubMed, Google Scholar, and Embase up to May 2024 was conducted to identify relevant studies. This study employs a systematic approach to explore the interplay between polysaccharides and the gut microbiota, focusing on cytokine-mediated and short-chain fatty acid (SCFA)-mediated pathways. The findings underscore the significant role of polysaccharides in shaping the composition and function of the gut microbiota, thereby influencing immune regulation and metabolic processes. However, further research is necessary to elucidate the detailed molecular mechanisms and translate these findings into clinical applications.

Fecal microbiota transplantation: transitioning from chaos and controversial realm to scientific precision era

With the popularization of modern lifestyles, the spectrum of intestinal diseases has become increasingly diverse, presenting significant challenges in its management. Traditional pharmaceutical interventions have struggled to keep pace with these changes, leaving many patients refractory to conventional pharmaceutical treatments. Fecal microbiota transplantation (FMT) has emerged as a promising therapeutic approach for enterogenic diseases. Still, controversies persist regarding its active constituents, mechanism of action, scheme of treatment evaluation, indications, and contraindications. In this review, we investigated the efficacy of FMT in addressing gastrointestinal and extraintestinal conditions, drawing from follow-up data on over 8000 patients. We systematically addressed the controversies surrounding FMT's clinical application. We delved into key issues such as its technical nature, evaluation methods, microbial restoration mechanisms, and impact on the host-microbiota interactions. Additionally, we explored the potential colonization patterns of FMT-engrafted new microbiota throughout the entire intestine and elucidated the specific pathways through which the new microbiota modulates host immunity, metabolism, and genome.

Protective Effects of Polygonatum sibiricum Polysaccharides Against Type 2 Diabetic Mice Induced by High-Fat Diet and Low-Dose Streptozotocin

Polysaccharides possessing hypoglycemic effects have shown promising results in treating diabetes. Polygonatum sibiricum polysaccharide (PSP) is one of the most active ingredients in the Chinese medicine P. sibiricum Redoute with many biological activities. However, its efficacy in alleviating type 2 diabetes mellitus (T2DM) remains unexplored. Our aim is to evaluate the protective effect of PSP against T2DM by measuring body weight and serum biochemical indicators, examining the histopathological images of pancreatic and liver tissues, detecting fecal short-chain fatty acid (SCFA) content, and analyzing the intestinal flora diversity and the microbiota structure in T2DM mice. The findings indicated that PSP treatment in T2DM mice could obviously decrease the fasting blood glucose and fasting insulin levels, ameliorate glucose tolerance, insulin resistance, lipid, and inflammatory factor levels, attenuate pancreatic and liver damage, and increase the fecal SCFA content. In addition, PSP could modulate the composition of gut microbiota in T2DM mice, resulting in the relative abundance of Firmicutes decreasing and that of Bacteroidetes increasing, along with the abundance of beneficial flora significantly increasing, especially SCFA-producing bacteria. The findings indicate that PSP administration protected against diabetes by controlling disordered glucolipid metabolism and modulating the gut microbiota, which provides a valuable strategy for the utilization of PSP to treat T2DM.

Gut-X Axis and Its Role in Poultry Bone Health: A Review

The normal development and growth of bones are critical for poultry health. With the rapid increase in poultry growth rates achieved over the last few decades, juvenile meat-type poultry exhibit a high incidence of leg weakness and lameness. These issues are significant contributors to poor animal welfare and substantial economic losses. Understanding the potential etiology of bone problems in poultry will aid in developing treatments for bone diseases. The gut microbiota represents the largest micro-ecosystem in animals and is closely related to many metabolic disorders, including bone disease. It achieves this by secreting secondary metabolites and coordinating with various tissues and organs through the circulatory system, which leads to the concept of the gut-X axis. Given its importance, modulating gut microbiota to influence the gut-X axis presents new opportunities for understanding and developing innovative therapeutic approaches for poultry bone diseases. In light of the extensive literature on this topic, this review focuses on the effects of gut microbiota on bone density and strength in poultry, both directly and indirectly, through the regulation of the gut-X axis. Our aim is to provide scientific insights into the bone health problems faced by poultry.

Intestinal Microbiota Modulation by Fecal Microbiota Transplantation in Nonalcoholic Fatty Liver Disease

Numerous factors are involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD), which are responsible for its development and progression as an independent entity, but also thanks to their simultaneous action. This is explained by the hypothesis of multiple parallel hits. These factors are insulin resistance, lipid metabolism alteration, oxidative stress, endoplasmic reticulum stress, inflammatory cytokine liberation, gut microbiota dysbiosis or gut-liver axis activation. This is a systematic review which has an aim to show the connection between intestinal microbiota and the role of its disbalance in the development of NAFLD. The gut microbiota is made from a wide spectrum of microorganisms that has a systemic impact on human health, with a well-documented role in digestion, energy metabolism, the stimulation of the immune system, synthesis of essential nutrients, etc. It has been shown that dysbiosis is associated with all three stages of chronic liver disease. Thus, the modulation of the gut microbiota has attracted research interest as a novel therapeutic approach for the management of NAFLD patients. The modification of microbiota can be achieved by substantial diet modification and the application of probiotics or prebiotics, while the most radical effects are observed by fecal microbiota transplantation (FMT). Given the results of FMT in the context of metabolic syndrome (MetS) and NAFLD in animal models and scarce pilot studies on humans, FMT seems to be a promising treatment option that could reverse intestinal dysbiosis and thereby influence the course of NAFLD.

Elevated propionate and its association with neurological dysfunctions in propionic acidemia

Propionate, a short-chain fatty acid (SCFA), has recently attracted attention for its various health benefits. However, elevated levels of propionate in certain pathological conditions can have adverse effects. Propionic acidemia (PA) is a rare metabolic disorder caused by mutations in the propionyl-CoA carboxylase (PCC) gene (PCCA or PCCB), leading to reduced PCC activity and impaired propionyl-CoA metabolism. This metabolic block at the PCC-mediated step results in the accumulation of propionyl-CoA and its metabolites, including propionate, contributing to various complications, such as neurological dysfunction, in patients with PA. This review examines propionate synthesis, its physiological role, its metabolism in healthy individuals and those with PA, and the pathological link between elevated propionate levels and neurological dysfunctions in PA patients. A deeper understanding of propionate metabolism under both normal and pathological conditions will help clarify the full spectrum of its metabolic effects.

Disturbances in the gut microbiota potentially associated with metabolic syndrome among patients living with HIV-1 and on antiretroviral therapy at Bafoussam Regional Hospital, Cameroon

BACKGROUND

This study investigates the gut microbiota components associated with metabolic syndrome in patients living with HIV-1 at Bafoussam Regional Hospital, West Cameroon, it focuses on gastrointestinal mucosal barrier disruption and dysbiosis, and their effects on persistent inflammation and metabolic disorders.

METHODS

A pilot study was conducted involving fourteen patients living with HIV-1. The patients were divided into two groups of seven in each group. One group consisted of patients with metabolic syndrome, and the other group included patients without metabolic syndrome. Gut microbiota was characterized using 16 S rRNA gene-targeted sequencing to analyze microbial diversity and composition. Beta diversity and the relative abundance of bacterial taxa were compared between patients with and without metabolic syndrome.

RESULTS

Patients living with HIV-1 and metabolic syndrome showed significantly altered beta diversity compared to those without metabolic syndrome. A higher relative abundance of Firmicutes and increased proliferation of Proteobacteria were observed in patients with metabolic syndrome. Additionally, a decrease in metabolically beneficial bacteria, such as Bifidobacterium sp., Lactobacillus sp., Akkermansia sp., and Faecalibacterium sp., was noted. Several beneficial bacterial species were associated with participants' metadata, suggesting potential links between gut microbiota and metabolic syndrome.

CONCLUSION

This preliminary study highlights that gut microbial balance, rather than the presence of specific bacteria, plays a crucial role in managing metabolic health in patients living with HIV-1. The altered gut microbiota in participants with metabolic syndrome emphasizes the need for further research into the optimal gut microbial structure. Understanding the interaction between gut microbiota changes and the chemical environment in these patients could guide targeted interventions to improve metabolic outcomes.

Isobutyrate exerts a protective effect against liver injury in a DSS-induced colitis by inhibiting inflammation and oxidative stress

BACKGROUND

Short-chain fatty acids have been reported to have anti-inflammatory and antioxidant functions; whether isobutyrate, a short-chain fatty acid, is protective against liver injury in a dextran sodium sulfate (DSS)-induced colitis and its molecular mechanism is unknown. In this study, DSS was used to induce a liver injury from a colitis model in piglets, which was expected to prevent and alleviate DSS-induced liver injury by feeding sodium isobutyrate in advance.

RESULTS

The results showed that sodium isobutyrate could restore DSS-induced histopathological changes in the liver, inhibit the activation of the toll-like receptor 4/myeloid differentiation primary response 88/nuclear factor kappa-B signaling pathway, and then reduce the DSS-induced release of pro-inflammatory cytokines tumor necrosis factor-α, interleukin 1β, and interleukin 6, reducing inflammatory response. Moreover, we found that sodium isobutyrate could play an antioxidant and apoptosis-reducing role by maintaining reduced mitochondrial function.

CONCLUSION

In conclusion, sodium isobutyrate has a preventive and protective effect on liver injury in a DSS-induced colitis. There is a potential application prospect for it in treating ulcerative-colitis-induced liver injuries. © 2024 Society of Chemical Industry.

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

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

When short-chain fatty acids meet type 2 diabetes mellitus: Revealing mechanisms, envisioning therapies

Evidence is accumulating that short-chain fatty acids (SCFAs) produced by the gut microbiota play pivotal roles in host metabolism. They contribute to the metabolic regulation and energy homeostasis of the host not only by preserving intestinal health and serving as energy substrates but also by entering the systemic circulation as signaling molecules, affecting the gut-brain axis and neuroendocrine-immune network. This review critically summarizes the current knowledge regarding the effects of SCFAs in the fine-tuning of the pathogenesis of type 2 diabetes mellitus (T2DM) and insulin resistance, with an emphasis on the complex relationships among diet, microbiota-derived metabolites, T2DM inflammation, glucose metabolism, and the underlying mechanisms involved. We hold an optimistic view that elucidating how diet can influence gut bacterial composition and activity, SCFA production, and metabolic functions in the host will advance our understanding of the mutual interactions of the intestinal microbiota with other metabolically active organs, and may pave the way for harnessing these pathways to develop novel personalized therapeutics for glucometabolic disorders.

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.

Metabolic preferences of astrocytes: Functional metabolic mapping reveals butyrate outcompetes acetate

Disruptions to the gut-brain-axis have been linked to neurodegenerative disorders. Of these disruptions, reductions in the levels of short-chain fatty acids (SCFAs), like butyrate, have been observed in mouse models of Alzheimer's disease (AD). Butyrate supplementation in mice has shown promise in reducing neuroinflammation, amyloid-β accumulation, and enhancing memory. However, the underlying mechanisms remain unclear. To address this, we investigated the impact of butyrate on energy metabolism in mouse brain slices, primary cultures of astrocytes and neurons and in-vivo by dynamic isotope labelling with [U-13C]butyrate and [1,2-13C]acetate to map metabolism via mass spectrometry. Metabolic competition assays in cerebral cortical slices revealed no competition between butyrate and the ketone body, β-hydroxybutyrate, but competition with acetate. Astrocytes favoured butyrate metabolism compared to neurons, suggesting that the astrocytic compartment is the primary site of butyrate metabolism. In-vivo metabolism investigated in the 5xFAD mouse, an AD pathology model, showed no difference in 13C-labelling of TCA cycle metabolites between wild-type and 5xFAD brains, but butyrate metabolism remained elevated compared to acetate in both groups, indicating sustained uptake and metabolism in 5xFAD mice. Overall, these findings highlight the role of astrocytes in butyrate metabolism and the potential use of butyrate as an alternative brain fuel source.

[Intestinal gluconeogenesis : When the intestine produces glucose to prevent obesity and hepatic steatosis]

Intestinal gluconeogenesis refers to the ability of the gut to produce glucose outside of meals. By initiating a gut-brain neural axis, its activation by dietary fiber or protein improves the regulation of energy balance. Recently, the creation of a genetic activation model of intestinal gluconeogenesis has demonstrated its anti-obesity, anti-diabetes and anti-hepatic steatosis effects. Interestingly, it increases thermogenesis in brown adipose tissue, thereby promoting energy expenditure and contributing to the fight against obesity. Therefore, targeting intestinal gluconeogenesis could be an innovative strategy to address metabolic diseases such as hepatic steatosis and diabetes, paving the way to new therapeutic approaches.

Gut Microbiome Regulation of Gut Hormone Secretion

The gut microbiome, comprising bacteria, viruses, fungi, and bacteriophages, is one of the largest microbial ecosystems in the human body and plays a crucial role in various physiological processes. This review explores the interaction between the gut microbiome and enteroendocrine cells (EECs), specialized hormone-secreting cells within the intestinal epithelium. EECs, which constitute less than 1% of intestinal epithelial cells, are key regulators of gut-brain communication, energy metabolism, gut motility, and satiety. Recent evidence shows that gut microbiota directly influence EEC function, maturation, and hormone secretion. For instance, commensal bacteria regulate the production of hormones like glucagon-like peptide 1 and peptide YY by modulating gene expression and vesicle cycling in EE cells. Additionally, metabolites such as short-chain fatty acids, derived from microbial fermentation, play a central role in regulating EEC signaling pathways that affect metabolism, gut motility, and immune responses. Furthermore, the interplay between gut microbiota, EECs, and metabolic diseases, such as obesity and diabetes, is examined, emphasizing the microbiome's dual role in promoting health and contributing to disease states. This intricate relationship between the gut microbiome and EECs offers new insights into potential therapeutic strategies for metabolic and gut disorders.

Cardiac energy metabolic disorder and gut microbiota imbalance: a study on the therapeutic potential of Shenfu Injection in rats with heart failure

Objective

To investigate the relationship between heart failure (HF) and gut microbiota-mediated energy metabolism, and to explore the role of Shenfu Injection in this process.

Materials and methods

In this study, Adriamycin-induced chronic heart failure (CHF) rat model was used and randomly divided into the blank control group (Normal, n = 9), HF control group (Model, n = 12), Shenfu Injection treatment group (SFI, n = 9), and positive drug control group (TMZ, n = 9). The changes in gut microbiota structure were analyzed by 16S rRNA high-throughput sequencing, the content of short-chain fatty acids (SCFAs) was detected by targeted metabolomics technology, and cardiac function and energy metabolism-related indicators were evaluated.

Results

Myocardial energy metabolism in HF rats was disordered, characterized by reduced fatty acid oxidation, enhanced anaerobic glycolysis of glucose, mitochondrial damage, and decreased ATP content; The gut microbiota of HF rats was imbalanced, with a reduction in beneficial bacteria, an increase in conditional pathogenic bacteria, and impaired intestinal barrier function; Both Shenfu Injection and trimetazidine improved myocardial energy metabolism and cardiac function, but Shenfu Injection was more significant in regulating gut microbiota and improving intestinal health; The production of SCFAs from the gut microbiota of HF rats increased, which may be closely related to myocardial energy metabolism; SCFAs-producing bacteria Akkermansia and Blautia played a key role in the development of HF, and their abundance was positively correlated with SCFAs content.

Conclusion

Shenfu Injection in treating HF may improve myocardial energy metabolism and intestinal health by regulating gut microbiota, especially the abundance of SCFAs-producing bacteria Akkermansia and Blautia, thereby exerting therapeutic effects. This provides theoretical support for treatment strategies based on gut microbiota.

Dietary Pea Fibre Improves Obesity, Intestinal Barrier, Reproductive Performance, Offspring Health of Parent Mice Deprived of Dietary Fibre

As a potential high-quality protein food, peas are enriched in protein and fibre. This study investigated the judicious utilisation of pea fibre and the impact of maternal diet on offspring health in mice. Thirty-six eight-week-old, female, healthy C57BL/6J mice were divided into three groups at random (n = 12 per group): deprived fibre diet (DFD), 5% pea fibre diet (LFD), and 10% pea fibre diet (HFD). After weaning, the offspring mice were fed the same diet as their parents; the respective corresponding groups were DFDO, LFDO, and HFDO. Fibre-deprived mice exhibited decreased average litter size, diminished reproductive performance, increased body weight, and intestinal barrier damage. Mice fed pea fibre showed increased litter size, improved fertility rate of parental mice, regulated body weight, and maintained a normal intestinal barrier morphology without inflammatory cell infiltration. Furthermore, 16S rRNA analysis revealed that pea fibre enhanced diversity and richness of the intestinal microbiota and altered microbial composition. Notably, changes in Lactobacillus and Parabacteroides in fibre-deprived mice suggest that pea fibre might be a potentially beneficial option for neuropsychiatric diseases. In conclusion, supplementing the diet of maternal mice with pea fibre can mitigate the aforementioned issues in their offspring. This study emphasised the crucial role of maternal fibre consumption in increasing litter size, promoting gut health in offspring, and reducing susceptibility to obesity.

Cellulose-like chitosan microfibrils facilitate targeted release and enhance the prolonged residence time of quercetin-selenium nanoparticles for Alzheimer's disease treatment

The effect of digestion on nanocarriers will affect the release and pharmacological effects of bioactive compounds in delivery systems. The digestion of cellulose is limited to gut microbiota, which offers a new research strategy for targeted delivery of bioactive compounds. Herein, positively charged cellulose-like chitosan/polyvinylpyrrolidone nanofiber was prepared to improve the residence time, colon target and gut microbiota regulation activity of quercetin decorated selenium nanoparticles (QUE@SeNPs/CS/PVPNFs). Selenium nanoparticles block the degradation of quercetin and QUE@SeNPs/CS/PVPNFs only decompose when caused by chitosanase secretion from gut microbiota. In vivo imaging showed that the residence time of QUE@SeNPs/CS/PVPNFs was longer than that of QUE@SeNPs. Thus, it significantly decreased the lipid concentrations in liver, which further inhibited insulin resistance in mice. Moreover, QUE@SeNPs/CS/PVPNFs treatment improves gut barrier integrity, increased the relative abundance of anti-obesity and anti-inflammation related bacterial including Akkermansia, Lactobacillus and Bacteroides. Consequently, the inflammatory factor (IL-β and TNF-α) levels in gut, liver and brain were also decreased. Nissl and PSD-95 staining indicated that QUE@SeNPs/CS/PVPNFs ameliorated synapse dysfunction in the brain. Therefore, QUE@SeNPs/CS/PVPNFs has a greater effect than QUE@SeNPs in improving cognitive ability in Morris water maze. Overall, QUE@SeNPs/CS/PVPNFs with prolonged residence time attenuates cognitive disorder via gut-liver-brain axis in AD.

Exploring the therapeutic potential of Chinese herbs on comorbid type 2 diabetes mellitus and Parkinson's disease: A mechanistic study

ETHNOPHARMACOLOGICAL RELEVANCE

Type 2 diabetes mellitus (T2DM) and Parkinson's disease (PD) are chronic conditions that affect the aging population, with increasing prevalence globally. The rising prevalence of comorbidity between these conditions, driven by demographic shifts, severely impacts the quality of life of patients, posing a significant burden on healthcare resources. Chinese herbal medicine has been used to treat T2DM and PD for millennia. Pharmacological studies have demonstrated that medicinal herbs effectively lower blood glucose levels and exert neuroprotective effects, suggesting their potential as adjunctive therapy for concurrent management of T2DM and PD.

AIM OF THE STUDY

To elucidate the shared mechanisms underlying T2DM and PD, particularly focusing on the potential mechanisms by which medicinal herbs (including herbal formulas, single herbs, and active compounds) may treat these diseases, to provide valuable insights for developing therapeutics targeting comorbid T2DM and PD.

MATERIALS AND METHODS

Studies exploring the mechanisms underlying T2DM and PD, as well as the treatment of these conditions with medicinal herbs, were extracted from several electronic databases, including PubMed, Web of Science, Google Scholar, and China National Knowledge Infrastructure (CNKI).

RESULTS

Numerous studies have shown that inflammation, oxidative stress, insulin resistance, impaired autophagy, gut microbiota dysbiosis, and ferroptosis are shared mechanisms underlying T2DM and PD mediated through the NLRP3 inflammasome, NF-κB, MAPK, Keap1/Nrf2/ARE, PI3K/AKT, AMPK/SIRT1, and System XC--GSH-GPX4 signaling pathways. Thirty-four medicinal herbs, including 2 herbal formulas, 4 single herbs, and 28 active compounds, have been reported to potentially exert anti-T2DM and anti-PD effects by targeting these shared mechanisms.

CONCLUSIONS

Traditional Chinese medicine effectively combats T2DM and PD through shared pathological mechanisms, highlighting their potential for application in treating these comorbid conditions.