Fructooligosaccharides act on the gut-bone axis to improve bone independent of Tregs and alter osteocytes in young adult C57BL/6 female mice

Targeting the gut-bone axis with probiotics and prebiotics is considered as a promising strategy to reduce the risk of osteoporosis. Gut-derived short chain fatty acids (SCFA) mediate the effects of probiotics on bone via Tregs, but it is not known whether prebiotics act through a similar mechanism. We investigated how 2 different prebiotics, tart cherry (TC) and fructooligosaccharide (FOS), affect bone, and whether Tregs are required for this response. Eight-wk-old C57BL/6 female mice were fed with diets supplemented with 10% w/w TC, FOS, or a control diet (Con; AIN-93M) diet, and they received an isotype control or CD25 Ab to suppress Tregs. The FOS diet increased BMC, density, and trabecular bone volume in the vertebra (~40%) and proximal tibia (~30%) compared to the TC and control diets (Con), irrespective of CD25 treatment. Both prebiotics increased (P < .01) fecal SCFAs, but the response was greater with FOS. To determine how FOS affected bone cells, we examined genes involved in osteoblast and osteoclast differentiation and activity as well as genes expressed by osteocytes. The FOS increased the expression of regulators of osteoblast differentiation (bone morphogenetic protein 2 [Bmp2], Wnt family member 10b [Wnt10b] and Osterix [Osx]) and type 1 collagen). Osteoclasts regulators were unaltered. The FOS also increased the expression of genes associated with osteocytes, including (Phex), matrix extracellular phosphoglycoprotein (Mepe), and dentin matrix acidic phosphoprotein 1 (Dmp-1). However, Sost, the gene that encodes for sclerostin was also increased by FOS as the number and density of osteocytes increased. These findings demonstrate that FOS has a greater effect on the bone mass and structure in young adult female mice than TC and that its influence on osteoblasts and osteocytes is not dependent on Tregs.

Prophylactic Administration of Gut Microbiome Metabolites Abrogated Microglial Activation and Subsequent Neuroinflammation in an Experimental Model of Japanese Encephalitis

Short-chain fatty acids (SCFAs) are gut microbial metabolic derivatives produced during the fermentation of ingested complex carbohydrates. SCFAs have been widely regarded to have a potent anti-inflammatory and neuro-protective role and have implications in several disease conditions, such as, inflammatory bowel disease, type-2 diabetes, and neurodegenerative disorders. Japanese encephalitis virus (JEV), a neurotropic flavivirus, is associated with life threatening neuro-inflammation and neurological sequelae in infected hosts. In this study, we hypothesize that SCFAs have potential in mitigating JEV pathogenesis. Postnatal day 10 BALB/c mice were intraperitoneally injected with either a SCFA mixture (acetate, propionate, and butyrate) or PBS for a period of 7 days, followed by JEV infection. All mice were observed for onset and progression of symptoms. The brain tissue was collected upon reaching terminal illness for further analysis. SCFA-supplemented JEV-infected mice (SCFA + JEV) showed a delayed onset of symptoms, lower hindlimb clasping score, and decreased weight loss and increased survival by 3 days (p < 0.0001) upon infection as opposed to the PBS-treated JEV-infected animals (JEV). Significant downregulation of inflammatory cytokines TNF-α, MCP-1, IL-6, and IFN-Υ in the SCFA + JEV group relative to the JEV-infected control group was observed. Inflammatory mediators, phospho-NF-kB (P-NF-kB) and iba1, showed 2.08 ± 0.1 and 3.132 ± 0.43-fold upregulation in JEV versus 1.19 ± 0.11 and 1.31 ± 0.11-fold in the SCFA + JEV group, respectively. Tissue section analysis exhibited reduced glial activation (JEV group─42 ± 2.15 microglia/ROI; SCFA + JEV group─27.07 ± 1.8 microglia/ROI) in animals that received SCFA supplementation prior to infection as seen from the astrocytic and microglial morphometric analysis. Caspase-3 immunoblotting showed 4.08 ± 1.3-fold upregulation in JEV as compared to 1.03 ± 0.14-fold in the SCFA + JEV group and TUNEL assay showed a reduced cellular death post-JEV infection (JEV-6.4 ± 1.5 cells/ROI and SCFA + JEV-3.7 ± 0.73 cells/ROI). Our study critically contributes to the increasing evidence in support of SCFAs as an anti-inflammatory and neuro-protective agent, we further expand its scope as a potential supplementary intervention in JEV-mediated neuroinflammation.

Catabolism of phenolics from grape peel and its effects on gut microbiota during in vitro colonic fermentation

BACKGROUND

Grape peels, the main by-products of wine processing, are rich in bioactive ingredients of phenolics, including proanthocyanidins, flavonoids and anthocyanins. Phenolics have the function of regulating intestinal microbiota and promoting intestinal health. From the perspective of the dietary nutrition of grape peel phenolics (GPP), this study was to investigate the influence of GPP on the composition and metabolism of human gut microbiota during in vitro fermentation.

RESULTS

The results indicated that GPP could decrease pH and promote the production of short-chain fatty acids (SCFAs). ACE and Chao1 indices in GPP group were lower than that of the Blank group. GPP enhanced the levels of Lachnospiraceae UCG-004, Bacteroidetes, and Roseburia, but reduced the Firmicutes/Bacteroidetes ratio. KEGG enrichment pathways related to phenolic acid metabolism mainly included flavonoid, anthocyanin, flavone and flavonol biosynthesis. Gut microbiota could accelerate the release and breakdown of phenolic compounds, resulting in a decrease in the content of hesperetin-7-O-glucoside, delphinidin-3-O-glucoside, and cyanidin-3-rutinoside etc. In vitro antibacterial test found that GPP increased the diameters of the inhibition zones of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in a dose-dependent manner.

CONCLUSION

The above results revealed that GPP might be a potential prebiotic-like to prevent diseases by improving gut health. This study could provide theoretical basis for potential to exploit GPP as dietary nutrition to maintain intestinal function. This article is protected by copyright. All rights reserved.

Butyrate and Propionate are Negatively Correlated with Obesity and Glucose Levels in Patients with Type 2 Diabetes and Obesity

Background

Growing evidence has demonstrated the important roles of gut microbiota and short chain fatty acids, especially acetate, propionate and butyrate, in the development of obesity and metabolic diseases. To date, the effects of acetate, propionate and butyrate on human adiposity and glucose metabolism remain controversial. This study aimed to explore the associations of systemically acetate, propionate and butyrate with obesity and glucose homeostasis in patients with type 2 diabetes (T2D) and obesity.

Methods

A total of 12 patients with T2D and obesity and 8 age- and sex-matched healthy individuals with BMI <24 kg/m2 were enrolled in this study. Height, weight, body composition, blood pressure, biochemical indices, a 75-g oral glucose tolerance test, and plasma acetate, propionate and butyrate were measured at baseline. Then, participants in T2D group were given a weight control therapy, in addition to conventional medication, and all the measurements were repeated 12 months from baseline. The direct segmental multi-frequency bioelectrical impedance analysis was used to assess body composition. Acetate, propionate and butyrate levels were determined by liquid chromatography coupled to tandem mass spectrometry.

Results

Butyrate concentration significantly increased from baseline after obvious weight loss (P<0.05). Correlation analysis showed that propionate was negatively correlated with percent of body fat (PBF) and 2-h plasma glucose (2-h PG) (P<0.05), and butyrate was negatively associated with body mass index, visceral fat area, PBF and 2-h PG (P<0.05). No association was found between acetate and obesity.

Conclusion

Butyrate and propionate are negatively correlated with obesity and glucose levels in patients with T2D and obesity.

Effects of dietary energy levels on microorganisms and short-chain fatty acids of rumen and tight junction proteins in Honghe Yellow cattle

This study was conducted to investigate the effects of dietary energy levels on microorganisms and short-chain fatty acids (SCFAs) of rumen and the expression of tight junction proteins in Honghe Yellow cattle. A total of fifteen male Honghe Yellow cattle were randomly divided into three treatments (five replicates per treatment), consisting of formulated energy concentrations of 5.90 MJ/kg (high-energy diet, group H), 5.60 MJ/kg (medium-energy diet, group M) and 5.30 MJ/kg (low-energy diet, group L). The results showed that compared with group H, the expression of Claudin-1 in rumen epithelium of groups M and L was increased, but the expression of ZO-1 was decreased (p < 0.05). Moreover, compared with group H, group M down-regulated the expression of Occludin and Claudin-1 in the brain (p < 0.05). For rumen bacteria, the dominant phyla included Bacteroidetes and Firmicutes, the abundance of Actinobacteriota in groups M and L was significantly increased compared with group H (p < 0.05). At the genus level, the relative abundance of Corynebacterium, Eubacterium_nodatum_group and Neisseraceae in groups M and L was significantly decreased compared with group H (p < 0.05). For rumen fungi, the dominant phyla included Basidiomycota, Ascomycota and Neocariastigomycota, the relative abundance of Ascomycetes was significantly higher than that of groups M and L compared with group H (p < 0.05). At the genus level, the relative abundance of Neocelimastigaceae and Myceliophthora in groups M and L was significantly reduced compared with group H (p < 0.05). Furthermore, the expression of Claudin-1 in rumen epithelium was significantly positively correlated with Actinobacteriota, Corynebacterium and Neisseriaceae. The expression of ZO-1 in the spinal cord was significantly positively correlated with Myceliophthora. The expression of Occludin in brain was positively correlated with valerate content (p < 0.05). In summary, dietary energy levels affected the rumen microbiota of Honghe Yellow cattle. The expression of Claudin-1 in rumen epithelium and the total SCFAs concentration were increased with decreasing dietary energy levels, but the expression of Claudin-1 in brain and ZO-1 in the spinal cord were reduced with decreasing dietary energy levels. Meanwhile, the rumen microbiota and SCFAs were significantly correlated with the expression of TJP.

Gut metabolome and microbiota signatures predict response to treatment with exclusive enteral nutrition in a prospective study in children with active Crohn's disease

BACKGROUND

Predicting response to exclusive enteral nutrition (EEN) in active Crohn's disease (CD) could lead to therapy personalization and pretreatment optimization.

OBJECTIVES

This study aimed to explore the ability of pretreatment parameters to predict fecal calprotectin (FCal) levels at EEN completion in a prospective study in children with CD.

METHODS

In children with active CD, clinical parameters, dietary intake, cytokines, inflammation-related blood proteomics, and diet-related metabolites, metabolomics and microbiota in feces, were measured before initiation of 8 wk of EEN. Prediction of FCal levels at EEN completion was performed using machine learning. Data are presented with medians (IQR).

RESULTS

Of 37 patients recruited, 15 responded (FCal < 250 μg/g) to EEN (responders) and 22 did not (nonresponders). Clinical and immunological parameters were not associated with response to EEN. Responders had lesser (μmol/g) butyrate [responders: 13.2 (8.63-18.4) compared with nonresponders: 22.3 (12.0-32.0); P = 0.03], acetate [responders: 49.9 (46.4-68.4) compared with nonresponders: 70.4 (57.0-95.5); P = 0.027], phenylacetate [responders: 0.175 (0.013-0.611) compared with nonresponders: 0.943 (0.438-1.35); P = 0.021], and a higher microbiota richness [315 (269-347) compared with nonresponders: 243 (205-297); P = 0.015] in feces than nonresponders. Responders consumed (portions/1000 kcal/d) more confectionery products [responders: 0.55 (0.38-0.72) compared with nonresponders: 0.19 (0.01-0.38); P = 0.045]. A multicomponent model using fecal parameters, dietary data, and clinical and immunological parameters predicted response to EEN with 78% accuracy (sensitivity: 80%; specificity: 77%; positive predictive value: 71%; negative predictive value: 85%). Higher taxon abundance from Ruminococcaceae, Lachnospiraceae, and Bacteroides and phenylacetate, butyrate, and acetate were the most influential variables in predicting lack of response to EEN.

CONCLUSIONS

We identify microbial signals and diet-related metabolites in feces, which could comprise targets for pretreatment optimization and personalized nutritional therapy in pediatric CD.

Postbiotics: emerging therapeutic approach in diabetic retinopathy

Diabetic retinopathy (DR) is a prevalent microvascular complication in diabetic patients that poses a serious risk as it can cause substantial visual impairment and even vision loss. Due to the prolonged onset of DR, lengthy treatment duration, and limited therapeutic effectiveness, it is extremely important to find a new strategy for the treatment of DR. Postbiotic is an emerging dietary supplement which consists of the inactivate microbiota and its metabolites. Numerous animal experiments have demonstrated that intervention with postbiotics reduces hyperglycemia, attenuates retinal peripapillary and endothelial cell damage, improves retinal microcirculatory dysfunction, and consequently delays the progression of DR. More strikingly, unlike conventional probiotics and prebiotics, postbiotics with small molecules can directly colonize the intestinal epithelial cells, and exert heat-resistant, acid-resistant, and durable for storage. Despite few clinical significance, oral administration with postbiotics might become the effective management for the prevention and treatment of DR. In this review, we summarized the basic conception, classification, molecular mechanisms, and the advances in the therapeutic implications of postbiotics in the pathogenesis of DR. Postbiotics present great potential as a viable adjunctive therapy for DR.

Alterations of circulating free fatty acids in patients with pemphigus vulgaris

Free fatty acids (FFA) have gained research interest owing to their functions in both local and systemic immune regulation. Changes in the serum levels of anti-inflammatory short chain fatty acids (SCFA), primarily derived from the gut microbiota, and pro-inflammatory medium (MCFA) and long (LCFA) chain fatty acids, derived from either the gut microbiota or the diet, have been associated with autoimmunity. Circulating FFA were retrospectively analysed by a gas chromatography-mass spectrometry method in the serum of 18 patients with pemphigus vulgaris (PV) at the baseline and 6 months (n = 10) after immunosuppressive treatments, and 18 healthy controls (HC). Circulating FFA were correlated with the Pemphigus Disease Area Index (PDAI) and serum concentrations of interferon-gamma (IFN-γ), Interleukin (IL)-17A, IL-5, IL-10 and IL-21. Principal Component analysis computed on FFA abundances revealed significant differences in the profile of SCFA (p = 0,012), MCFA (p = 0.00015) and LCFA (p = 0,035) between PV patients and HC, which were not significantly changed by immunosuppressive treatments. PV patients showed a significantly lower serum concentration of propionic (p < 0.0005) and butyric (p < 0.0005) acids, SCFA with anti-inflammatory functions, while hexanoic (p < 0.0005) and hexadecanoic (p = 0.0006) acids, pro-inflammatory MCFA and LCFA respectively, were over-represented. Treatments induced a significant decrease of hexanoic (p = 0.035) and a further increase of hexadecanoic (p = 0.046) acids. Positive correlations emerged between IFN-γ and acetic acid (Rho = 0.60), IFN-γ and hexanoic acid (Rho = 0.46), IL-5 and both hexadecanoic acid (Rho = 0.50) and octadecanoic acid (Rho = 0.53), butyric acid and PDAI (Rho = 0.53). PV was associated with a remarked imbalance of circulating FFA compared to HC. The serum alterations of SCFA, MCFA, and LCFA may contribute to promoting inflammation in PV. Deeper insights into the immunomodulatory functions of these molecules may pave the way for personalized dietary interventions in PV patients.

Systematic review of the association between short chain fatty acids and allergic diseases

We performed a systematic review to investigate the current evidence on the association between allergic diseases and short chain fatty acids (SCFAs), which are microbially produced and suggested as one mechanism on how gut microbiome affects the risk of allergic diseases. Medline, Embase and Web of Science were searched from data inception until September 2022. We identified 37 papers, of which 17 investigated prenatal or early childhood SCFAs and the development of allergic diseases in childhood, and 20 assessed SCFAs in patients with pre-existing allergic diseases. Study design, study populations, outcome definition, analysis method and reporting of the results varied between papers. Overall, there was some evidence showing that the three main SCFAs (acetate, propionate and butyrate) in the first few years of life had a protective effect against allergic diseases, especially for atopic dermatitis, wheeze or asthma and IgE-mediated food allergy in childhood. The association between each SCFA and allergic disease appeared to be different by disease and the age of assessment. Further research that can determine the potentially timing specific effect of each SCFA will be useful to investigate how SCFAs can be used in treatment or in prevention against allergic diseases.

Molecular Targets of Valeric Acid: A Bioactive Natural Product for Endocrine, Metabolic, and Immunological Disorders

BACKGROUNDS

Postbiotics produced by gut microbiota have exhibited diverse pharmacological activities. Valeric acid, a postbiotic material produced by gut microbiota and some plant species like valerian, has been explored to have diverse pharmacological activities.

METHODS

This narrative review aims to summarise the beneficial role of valeric acid for different health conditions along with its underlying mechanism. In order to get ample scientific evidence, various databases like Science Direct, PubMed, Scopus, Google Scholar and Google were exhaustively explored to collect relevant information. Collected data were arranged and analyzed to reach meaningful a conclusion regarding the bioactivity profiling of valeric acid, its mechanism, and future prospects.

RESULTS

Valeric acid belongs to short-chain fatty acids (SCFAs) compounds like acetate, propionate, butyrate, pentanoic (valeric) acid, and hexanoic (caproic) acid. Valeric acid has been identified as one of the potent histone deacetylase (HDAC) inhibitors. In different preclinical in -vitro and in-vivo studies, valeric acid has been found to have anti-cancer, anti-diabetic, antihypertensive, anti-inflammatory, and immunomodulatory activity and affects molecular pathways of different diseases like Alzheimer's, Parkinson's, and epilepsy.

CONCLUSION

These findings highlight the role of valeric acid as a potential novel therapeutic agent for endocrine, metabolic and immunity-related health conditions, and it must be tested under clinical conditions to develop as a promising drug.

A novel treatment to enhance survival for end stage triple negative breast cancer using repurposed veterinary anthelmintics combined with gut‑supporting/immune enhancing molecules

Patients with end‑stage metastatic disease have limited treatment options and those diagnosed with triple negative breast cancer (Her2, Estrogen receptor, Progesterone receptor) have a poor prognosis. Using a triple negative mammary tumor model selected for brain metastasis (4T1Br4) in the mouse, treatment options that may increase survival when therapeutics are applied at post‑metastasis were assessed. Anti‑parasitic benzimidazoles (BZs) destabilize microtubules, inhibit metabolic pathways, reduce cell proliferation, and induce apoptosis in tumor cells. Co‑administration of two BZs was selected, oxfendazole (OFZ) and parbendazole (PBZ), shown to overcome resistance development in anthelmintic effects by imposing metabolic delay to assess if multiple BZ approach is also suitable to enhance anticancer effects. It has been previously reported that treatment of mammary tumor‑bearing mice at an early stage with chitin microparticles (CMPs) decreased tumor growth and metastases by enhancing both innate M1 macrophage and TH1 adaptive immune response. Oral administration of CMPs was previously revealed to affect the gut in intestinal inflammation. A combination BZ (OFZ/PBZ) and CMP treatment was tested to target tumor development and metastasis and effects were compared in response to monotherapies of the same compounds or to untreated mice. The results demonstrated increased survival, decreased tumor cell proliferation, decreased metastasis in lungs and brain, increased levels of fecal SCFAs butyric, acetic, propionic and valeric acids with increased butyric and propionic acid levels in brain biopsies in combination treated compared with untreated mice. At the primary tumor, SCFA receptor FFAR2 expression was increased in combination treatment compared with untreated mice, suggestive of a non‑invasive cancer phenotype. The superior cytotoxic effects of OFZ/PBZ were confirmed as opposed to single treatment with OFZ or PBZ using 3D spheroids generated from a human breast cancer cell line, MDA‑MB‑468. These data are compelling for treatment option possibility even at late stages of metastasized breast cancer.

Elephantopus scaber L. Polysaccharides Alleviate Heat Stress-Induced Systemic Inflammation in Mice via Modulation of Characteristic Gut Microbiota and Metabolites

Elephantopus scaber L. (ESL) is a Chinese herb that is used both as a food and medicine, often being added to soups in summer in south China to relieve heat stress (HS), but its exact mechanism of action is unknown. In this study, heat-stressed mice were gavaged with ESL polysaccharides (ESLP) at 0, 150, 300, and 450 mg/kg/d-1 (n = 5) for seven days. The gut microbiota composition, short-chain fatty acids (SCFAs), seven neurotransmitters in faeces, expression of intestinal epithelial tight junction (TJ) proteins (Claudin-1, Occludin), and serum inflammatory cytokines were measured. The low dose of ESLP (ESLL) improved the adverse physiological conditions; significantly reduced the cytokines (TNF-α, IL-1β, IL-6) and lipopolysaccharide (LPS) levels (p < 0.05); upregulated the expression of Claudin-1; restored the gut microbiota composition including Achromobacter and Oscillospira, which were at similar levels to those in the normal control group; significantly increased beneficial SCFAs like butyric acid and 5-HT levels in the faeces of heat-stressed mice; and significantly decreased the valeric acid and glutamic acid level. The level of inflammatory markers significantly correlated with the above-mentioned indicators (p < 0.05). Thus, ESLL reduced the HS-induced systemic inflammation by optimizing gut microbiota (Achromobacter, Oscillospira) abundance, increasing gut beneficial SCFAs like butyric acid and 5-HT levels, and reducing gut valeric and glutamic acid levels.

An Analysis of the Gut Microbiota and Related Metabolites following PCSK9 Inhibition in Statin-Treated Patients with Elevated Levels of Lipoprotein(a)

BACKGROUND

Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of global mortality, often associated with high blood levels of LDL cholesterol (LDL-c). Medications like statins and PCSK9 inhibitors, are used to manage LDL-c levels and reduce ASCVD risk. Recent findings connect the gut microbiota and its metabolites to ASCVD development. We showed that statins modulate the gut microbiota including the production of microbial metabolites involved in the regulation of cholesterol metabolism such as short chain fatty acids (SCFAs) and bile acids (BAs). Whether this pleiotropic effect of statins is associated with their antimicrobial properties or it is secondary to the modulation of cholesterol metabolism in the host is unknown. In this observational study, we evaluated whether alirocumab, a PCSK9 inhibitor administered subcutaneously, alters the stool-associated microbiota and the profiles of SCFAs and BAs.

METHODS

We used stool and plasma collected from patients enrolled in a single-sequence study using alirocumab. Microbial DNA was extracted from stool, and the bacterial component of the gut microbiota profiled following an amplicon sequencing strategy targeting the V3-V4 region of the 16S rRNA gene. Bile acids and SCFAs were profiled and quantified in stool and plasma using mass spectrometry.

RESULTS

Treatment with alirocumab did not alter bacterial alpha (Shannon index, p = 0.74) or beta diversity (PERMANOVA, p = 0.89) in feces. Similarly, circulating levels of SCFAs (mean difference (95% confidence interval (CI)), 8.12 [-7.15-23.36] µM, p = 0.25) and BAs (mean difference (95% CI), 0.04 [-0.11-0.19] log10(nmol mg-1 feces), p = 0.56) were equivalent regardless of PCSK9 inhibition. Alirocumab therapy was associated with increased concentration of BAs in feces (mean difference (95% CI), 0.20 [0.05-0.34] log10(nmol mg-1 feces), p = 0.01).

CONCLUSION

In statin-treated patients, the use of alirocumab to inhibit PCSK9 leads to elevated levels of fecal BAs without altering the bacterial population of the gut microbiota. The association of alirocumab with increased fecal BA concentration suggests an additional mechanism for the cholesterol-lowering effect of PCSK9 inhibition.

The health benefits of dietary short-chain fatty acids in metabolic diseases

Short-chain fatty acids (SCFAs) are a subset of fatty acids that play crucial roles in maintaining normal physiology and developing metabolic diseases, such as obesity, diabetes, cardiovascular disease, and liver disease. Even though dairy products and vegetable oils are the direct dietary sources of SCFAs, their quantities are highly restricted. SCFAs are produced indirectly through microbial fermentation of fibers. The biological roles of SCFAs in human health and metabolic diseases are mainly due to their receptors, GPR41 and GPR43, FFAR2 and FFAR3. Additionally, it has been demonstrated that SCFAs modulate DNMTs and HDAC activities, inhibit NF-κB-STAT signaling, and regulate G(i/o)βγ-PLC-PKC-PTEN signaling and PPARγ-UCP2-AMPK autophagic signaling, thus mitigating metabolic diseases. Recent studies have uncovered that SCFAs play crucial roles in epigenetic modifications of DNAs, RNAs, and post-translational modifications of proteins, which are critical regulators of metabolic health and diseases. At the same time, dietary recommendations for the purpose of SCFAs have been proposed. The objective of the review is to summarize the most recent research on the role of dietary SCFAs in metabolic diseases, especially the signal transduction of SCFAs in metabolic diseases and their functional efficacy in different backgrounds and models of metabolic diseases, at the same time, to provide dietary and nutritional recommendations for using SCFAs as food ingredients to prevent metabolic diseases.

[Effect of Zuogui Jiangtang Jieyu Formula on intestinal flora and short-chain fatty acid metabolism in rats with diabetes mellitus complicated with depression]

This study aimed to investigate the regulatory effects of Zuogui Jiangtang Jieyu Formula(ZJJ) on the intestinal flora, short chain fatty acids(SCFAs), and neuroinflammation in rats with diabetes mellitus complicated depression(DD). The DD model was established in rats and model rats were randomly divided into a model group, a positive drug(metformin + fluoxetine) group, a ZJJ low-dose group, and a ZJJ high-dose group, with eight rats in each group. Another eight rats were assigned to the blank group. Subsequently, depressive-like behavior test was conducted on the rats, and cerebrospinal fluid samples were collected to measure pro-inflammatory cytokines [interleukin-1β(IL-1β), interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α)]. Blood serum samples were collected to measure proteins related to the hypothalamic-pituitary-adrenal axis(HPA axis), including corticotropin-releasing hormone(CRH), adrenocorticotropic hormone(ACTH), and cortisol(CORT), as well as glucose metabolism. Gut contents were collected from each group for 16S rRNA sequencing analysis of intestinal flora and SCFAs sequencing. The results indicated that ZJJ not only improved glucose metabolism in DD rats(P<0.01) but also alleviated depressive-like behavior(P<0.05) and HPA axis hyperactivity(P<0.05 or P<0.01). Besides, it also improved the neuroinflammatory response in the brain, as evidenced by a significant reduction in pro-inflammatory cytokines in cerebrospinal fluid(P<0.05 or P<0.01). Additionally, ZJJ improved the intestinal flora, causing the intestinal flora in DD rats to resemble that of the blank group, characterized by an increased Firmicutes abundance. ZJJ significantly increased the levels of SCFAs(acetic acid, butyric acid, valeric acid, and isovaleric acid)(P<0.01). Therefore, it is deduced that ZJJ can effectively ameliorate intestinal flora dysbiosis, regulate SCFAs, and thereby improve both glucose metabolism disturbances and depressive-like behavior in DD.

Chemopreventive Effect of an In Vitro Digested and Fermented Plant Sterol-Enriched Wholemeal Rye Bread in Colon Cancer Cells

Diet is crucial for the prevention of colorectal cancer. Whole grains are the source of beneficial compounds for this, such as fiber. The enrichment of wholemeal rye bread with plant sterols (PSs) could increase its beneficial effects. This study aimed to assess the potential antiproliferative effect of this enriched food on colon adenocarcinoma cells (Caco-2) compared with a non-enriched one. After a human oral chewing, simulated semi-dynamic gastrointestinal digestion and colonic fermentation in a simgi® system, fermentation liquids (FLs) obtained were used as treatment for cells. Cytotoxicity assay showed that samples diluted 1/5 (v/v) with DMEM are not toxic for non-tumoral cells, whereas they damage tumoral cells. Samples with PS (FLPS) produced a higher chemopreventive effect (vs. blank) in MTT and apoptosis assays, as well as higher gene expression of TP53 and Casp8. Nevertheless, FL0 (without PS) produced a higher chemopreventive effect in a cell cycle and reduced glutathione and calcium assays, besides producing higher gene expression of Casp3 and lower CCND1. The distinct antiproliferative effect of both FLs is attributed to differences in PSs, short chain fatty acids (lower concentration in FLPS vs. FL0) and antioxidant compounds. These results may support wholemeal rye bread consumption as a way of reducing the risk of colorectal cancer development, although further research would be needed.

Estrobolome dysregulation is associated with altered immunometabolism in a mouse model of endometriosis

Introduction

Endometriosis is a painful disease that affects around 5% of women of reproductive age. In endometriosis, ectopic endometrial cells or seeded endometrial debris grow in abnormal locations including the peritoneal cavity. Common manifestations of endometriosis include dyspareunia, dysmenorrhea, chronic pelvic pain and often infertility and symptomatic relief or surgical removal are mainstays of treatment. Endometriosis both promotes and responds to estrogen imbalance, leading to intestinal bacterial estrobolome dysregulation and a subsequent induction of inflammation.

Methods

In the current study, we investigated the linkage between gut dysbiosis and immune metabolic response in endometriotic mice. Ovariectomized BALB/c mice received intraperitoneal transplantation of endometrial tissue from OVX donors (OVX+END). Control groups included naïve mice (Naïve), naïve mice that received endometrial transplants (Naive+END) and OVX mice that received the vehicle (OVX+VEH). Colonic content was collected 2 weeks post-transplantation for 16s rRNA pyrosequencing and peritoneal fluid was collected to determine the phenotype of inflammatory cells by flow cytometry.

Results

We noted a significant increase in the number of peritoneal fluid cells, specifically, T cells, natural killer (NK) cells, and NKT cells in OVX+END mice. Phylogenetic taxonomy analysis showed significant dysbiosis in OVX+END mice, with an increase in abundance of Phylum Tenericutes, Class Mollicutes, Order Aneroplasmatales, and Genus Aneroplasma, and a decrease in Order Clostridiales, and Genus Dehalobacterium, when compared to OVX+VEH controls. The metabolomic profile showed an increase in some tricarboxylic acid cycle (TCA)-related metabolites accompanied by a reduction in short-chain fatty acids (SCFA) such as butyric acid in OVX+END mice. Additionally, the mitochondrial and ATP production of immune cells was enforced to a maximal rate in OVX+END mice when compared to OVX+VEH mice.

Conclusion

The current study demonstrates that endometriosis alters the gut microbiota and associated immune metabolism.

Akkermansia muciniphila supplementation prevents cognitive impairment in sleep-deprived mice by modulating microglial engulfment of synapses

The microbiome-gut-brain axis plays a crucial role in many neurological diseases, including mild cognitive impairment. Sleep deprivation (SD) induces cognitive decline accompanied by alterations in the gut microbiota. However, the role of gut microbiota alterations in SD-induced cognitive dysfunction and the underlying mechanisms remain unclear. Here, we found that dysbiosis of the gut microbiota following pretreatment with broad-spectrum antibiotics worsens SD-induced cognitive impairment in mice. Fecal microbiota transplantation from SD mice to healthy mice induced cognitive impairment. Additionally, the abundance of Akkermansia muciniphila (A. muciniphila) in the mouse gut microbiota was significantly reduced after 7 days of SD. A. muciniphila pretreatment alleviated cognitive dysfunction and prevented synaptic reduction in the hippocampus in SD mice. A. muciniphila pretreatment inhibited extensive microglial activation and synaptic engulfment in the hippocampus of SD mice. Metabolomics analysis revealed that A. muciniphila pretreatment increased the serum acetate and butanoic acid levels in SD mice. Finally, pretreatment with short-chain fatty acids (SCFAs) inhibited microglial synaptic engulfment and prevented neuronal synaptic loss in SD mice and primary microglia-neuron co-culture following LPS stimulation. Together, our findings illustrate that gut dysbiosis plays an essential role in SD-induced cognitive impairment by activating microglial engulfment at synapses. A. muciniphila supplementation may be a novel preventative strategy for SD-induced cognitive dysfunction, by increasing SCFAs production and maintaining microglial homeostasis.

Microbial community-scale metabolic modeling predicts personalized short chain fatty acid production profiles in the human gut

Microbially-derived short chain fatty acids (SCFAs) in the human gut are tightly coupled to host metabolism, immune regulation, and integrity of the intestinal epithelium. However, the production of SCFAs can vary widely between individuals consuming the same diet, with lower levels often associated with disease. A systems-scale mechanistic understanding of this heterogeneity is lacking. We present a microbial community-scale metabolic modeling (MCMM) approach to predict individual-specific SCFA production profiles. We assess the quantitative accuracy of our MCMMs using in vitro, ex vivo, and in vivo data. Next, we show how MCMM SCFA predictions are significantly associated with blood-derived clinical chemistries, including cardiometabolic and immunological health markers, across a large human cohort. Finally, we demonstrate how MCMMs can be leveraged to design personalized dietary, prebiotic, and probiotic interventions that optimize SCFA production in the gut. Our results represent an important advance in engineering gut microbiome functional outputs for precision health and nutrition.

Buckwheat (Fagopyrum esculentum) Hulls Are a Rich Source of Fermentable Dietary Fibre and Bioactive Phytochemicals

Pseudo-cereals such as buckwheat (Fagopyrum esculentum) are valid candidates to promote diet biodiversity and nutrition security in an era of global climate change. Buckwheat hulls (BHs) are currently an unexplored source of dietary fibre and bioactive phytochemicals. This study assessed the effects of several bioprocessing treatments (using enzymes, yeast, and combinations of both) on BHs' nutrient and phytochemical content, their digestion and metabolism in vitro (using a gastrointestinal digestion model and mixed microbiota from human faeces). The metabolites were measured using targeted LC-MS/MS and GC analysis and 16S rRNA gene sequencing was used to detect the impact on microbiota composition. BHs are rich in insoluble fibre (31.09 ± 0.22% as non-starch polysaccharides), protocatechuic acid (390.71 ± 31.72 mg/kg), and syringaresinol (125.60 ± 6.76 mg/kg). The bioprocessing treatments significantly increased the extractability of gallic acid, vanillic acid, p-hydroxybenzoic acid, syringic acid, vanillin, syringaldehyde, p-coumaric acid, ferulic acid, caffeic acid, and syringaresinol in the alkaline-labile bound form, suggesting the bioaccessibility of these phytochemicals to the colon. Furthermore, one of the treatments, EC_2 treatment, increased significantly the in vitro upper gastrointestinal release of bioactive phytochemicals, especially for protocatechuic acid (p < 0.01). The BH fibre was fermentable, promoting the formation mainly of propionate and, to a lesser extent, butyrate formation. The EM_1 and EC_2 treatments effectively increased the content of insoluble fibre but had no effect on dietary fibre fermentation (p > 0.05). These findings promote the use of buckwheat hulls as a source of dietary fibre and phytochemicals to help meet dietary recommendations and needs.

Postbiotics in rheumatoid arthritis: emerging mechanisms and intervention perspectives

Rheumatoid arthritis (RA) is a prevalent chronic autoimmune disease that affects individuals of all age groups. Recently, the association between RA and the gut microbiome has led to the investigation of postbiotics as potential therapeutic strategies. Postbiotics refer to inactivated microbial cells, cellular components, or their metabolites that are specifically intended for the microbiota. Postbiotics not only profoundly influence the occurrence and development of RA, but they also mediate various inflammatory pathways, immune processes, and bone metabolism. Although they offer a variety of mechanisms and may even be superior to more conventional "biotics" such as probiotics and prebiotics, research on their efficacy and clinical significance in RA with disruptions to the intestinal microbiota remains limited. In this review, we provide an overview of the concept of postbiotics and summarize the current knowledge regarding postbiotics and their potential use in RA therapy. Postbiotics show potential as a viable adjunctive therapy option for RA.

Fecal short chain fatty acids modify therapeutic effects of sleeve gastrectomy

Aims

We aimed to investigate changes of fecal short chain fatty acids (SCFAs) and their association with metabolic benefits after sleeve gastrectomy (SG). Specifically, whether pre-surgery SCFAs modify surgical therapeutic effects was determined.

Methods

62 participants with measurements of fecal SCFAs and metabolic indices before and 1, 3, 6 months after SG were included. Changes of fecal SCFAs and their association with post-surgery metabolic benefits were calculated. Then, participants were stratified by medians of pre-surgery fecal SCFAs and modification effects of pre-surgery fecal SCFAs on surgical therapeutic effects were investigated, through calculating interaction of group by surgery.

Results

Fecal SCFAs were markedly changed by SG. Changes of propionate and acetate were positively correlated with serum triglycerides and total cholesterol, respectively. Notably, high pre-surgery fecal hexanoate group showed a better effect of SG treatment on lowering body weight (P=0.01), BMI (P=0.041) and serum triglycerides (P=0.031), and low pre-surgery fecal butyrate had a better effect of SG on lowering ALT (P=0.003) and AST (P=0.019).

Conclusion

Fecal SCFAs were changed and correlated with lipid profiles improvement after SG. Pre-surgery fecal hexanoate and butyrate were potential modifiers impacting metabolic benefits of SG.

The short-chain fatty acid crotonate reduces invasive growth and immune escape of Candida albicans by regulating hyphal gene expression

Microbes are exposed to nutritional and stress challenges in their environmental and host niches. To rise to these challenges, they regulate transcriptional programs that enable cellular adaptation. For instance, metabolite concentrations regulate post-translational modifications of chromatin, such as histone acetylation. In this way, metabolic signals are integrated with transcription. Over the last decade, several histone acylations have been discovered, including histone crotonylation. Their roles in microbial biology, environmental adaptation, and microbe-host interactions are incompletely defined. Here we show that the short-chain fatty acid crotonate, which is used to study histone crotonylation, changes cell morphology and immune interactions of Candida albicans. Crotonate reduces invasive hyphal morphogenesis of C. albicans within macrophages, thereby delaying macrophage killing and pathogen escape, as well as reducing inflammatory cytokine maturation. Crotonate's ability to reduce hyphal growth is environmentally contingent and pronounced within macrophages. Moreover, crotonate is a stronger hyphal inhibitor than butyrate under the conditions that we tested. Crotonate causes increased histone crotonylation in C. albicans under hyphal growth conditions and reduces transcription of hyphae-induced genes in a manner that involves the Nrg1 repressor pathway. Increasing histone acetylation by histone deacetylase inhibition partially rescues hyphal growth and gene transcription in the presence of crotonate. These results indicate that histone crotonylation might compete with acetylation in the regulation of hyphal morphogenesis. Based on our findings, we propose that diverse acylations of histones (and likely also non-histone proteins) enable C. albicans to respond to environmental signals, which in turn regulate its cell morphology and host-pathogen interactions.IMPORTANCEMacrophages curtail the proliferation of the pathogen Candida albicans within human body niches. Within macrophages, C. albicans adapts its metabolism and switches to invasive hyphal morphology. These adaptations enable fungal growth and immune escape by triggering macrophage lysis. Transcriptional programs regulate these metabolic and morphogenetic adaptations. Here we studied the roles of chromatin in these processes and implicate lysine crotonylation, a histone mark regulated by metabolism, in hyphal morphogenesis and macrophage interactions by C. albicans. We show that the short-chain fatty acid crotonate increases histone crotonylation, reduces hyphal formation within macrophages, and slows macrophage lysis and immune escape of C. albicans. Crotonate represses hyphal gene expression, and we propose that C. albicans uses diverse acylation marks to regulate its cell morphology in host environments. Hyphal formation is a virulence property of C. albicans. Therefore, a further importance of our study stems from identifying crotonate as a hyphal inhibitor.

Dietary phosphate disturbs of gut microbiome in mice

Disorder of phosphate metabolism is a common pathological condition in chronic kidney disease patients. Excessive intake of dietary phosphate deteriorates chronic kidney disease and various complications including cardiovascular and infectious diseases. Recent reports have demonstrated that gut microbiome disturbance is associated with both the etiology and progression of chronic kidney disease. However, the relationship between dietary phosphate and gut microbiome remains unknown. Here, we examined the effects of excessive intake of phosphate on gut microbiome. Five-week-old male C57BL/6J mice were fed either control diet or high phosphate diet for eight weeks. Analysis of the gut microbiota was carried out using MiSeq next generation sequencer, and short-chain fatty acids were determined with GC-MS. In analysis of gut microbiota, significantly increased in Erysipelotrichaceae and decreased in Ruminococcaceae were observed in high phosphate diet group. Furthermore, high phosphate diet induced reduction of microbial diversity and decreased mRNA levels of colonic tight junction markers. These results suggest that the excessive intake of dietary phosphate disturbs gut microbiota and affects intestinal barrier function.

Targeting microbiota in dietary obesity management: a systematic review on randomized control trials in adults

Obesity is an alarming public health problem. Tailored nutritional therapy is advisable since emerging evidence on complex cross-talks among multifactorial agents. In this picture, the gut microbiota is highly individualized and intricately dependent on dietary patterns, with implications for obesity management. Most of the papers on the topic are observational and often conflicting. This review aimed to systematically organize the body of evidence on microbiota deriving from dietary trials in adult obesity giving the most certain phylogenetic, and metabolomic signatures in relation to both the host metabolism and phenotype changes published until now. We retrieved 18 randomized control trials on 1385 subjects with obesity who underwent several dietary interventions, including standard diet and healthy dietary regimens. Some phyla and species were more related to diets rich in fibers and others to healthy diets. Weight loss, metabolism improvements, inflammatory markers decrease were specifically related to different microorganisms or functions. The Prevotella/Bacteroides ratio was one of the most reported predictors. People with the burden of obesity comorbidities had the most significant taxonomic changes in parallel with a general improvement. These data emphasize the possibility of using symbiotic approaches involving tailored diets, microbiota characteristics, and maybe drugs to treat obesity and metabolic disorders. We encourage Authors to search for specific phylogenetic associations beyond a too generally reported Firmicutes/Bacteroides ratio.

Sex differences in a mouse model of diet-induced obesity: the role of the gut microbiome

Background

Recent decades have seen an exponential rise in global obesity prevalence, with rates nearly doubling in a span of forty years. A comprehensive knowledge base regarding the systemic effects of obesity is required to create new preventative and therapeutic agents effective at combating the current obesity epidemic. Previous studies of diet-induced obesity utilizing mouse models have demonstrated a difference in bodyweight gain by sex. In such studies, female mice gained significantly less weight than male mice when given the same high fat (HF) diet, indicating a resistance to diet-induced obesity. Research has also shown sex differences in gut microbiome composition between males and females, indicated to be in part a result of sex hormones. Understanding metabolic differences between sexes could assist in the development of new measures for obesity prevention and treatment. This study aimed to characterize sex differences in weight gain, plasma lipid profiles, fecal microbiota composition, and fecal short chain fatty acid levels. We hypothesized a role for the gut microbiome in these sex differences that would be normalized following microbiome depletion.

Methods

A mouse model was used to study these effects. Mice were divided into treatment groups by sex, diet, and presence/absence of an antibiotic cocktail to deplete genera in the gut microbiome. We hypothesized that sex differences would be present both in bodyweight gain and systemic measures of obesity, including hormone and circulating free fatty acid levels.

Results

We determined statistically significant differences for sex and/or treatment for the outcome measures. We confirm previous findings in which male mice gained significantly more weight than female mice fed the same high fat diet. However, sex differences persisted following antibiotic administration for microbiome depletion.

Conclusions

We conclude that sex differences in the gut microbiome may contribute to sex differences in obesity, but they do not explain all of the differences.

Gut microbiota-derived short chain fatty acids act as mediators of the gut-brain axis targeting age-related neurodegenerative disorders: a narrative review

Neurodegenerative diseases associated with aging are often accompanied by cognitive decline and gut microbiota disorder. But the impact of gut microbiota on these cognitive disturbances remains incompletely understood. Short chain fatty acids (SCFAs) are major metabolites produced by gut microbiota during the digestion of dietary fiber, serving as an energy source for gut epithelial cells and/or circulating to other organs, such as the liver and brain, through the bloodstream. SCFAs have been shown to cross the blood-brain barrier and played crucial roles in brain metabolism, with potential implications in mediating Alzheimer's disease (AD) and Parkinson's disease (PD). However, the underlying mechanisms that SCFAs might influence psychological functioning, including affective and cognitive processes and their neural basis, have not been fully elucidated. Furthermore, the dietary sources which determine these SCFAs production was not thoroughly evaluated yet. This comprehensive review explores the production of SCFAs by gut microbiota, their transportation through the gut-brain axis, and the potential mechanisms by which they influence age-related neurodegenerative disorders. Also, the review discusses the importance of dietary fiber sources and the challenges associated with harnessing dietary-derived SCFAs as promoters of neurological health in elderly individuals. Overall, this study suggests that gut microbiota-derived SCFAs and/or dietary fibers hold promise as potential targets and strategies for addressing age-related neurodegenerative disorders.

Influence of Brown or Germinated Brown Rice Supplementation on Fecal Short-Chain Fatty Acids and Microbiome in Diet-Induced Insulin-Resistant Mice

Intake of whole grain foods is associated with improving metabolic profile compared to refined grain products, but the underlying mechanism remains unclear. The present study examined the effects of brown rice (BRR) or germinated brown rice (GBR) supplementation on fecal short-chain fatty acids (SCFAs), and relationship with gut microbiota, metabolism and inflammation in high fat (HF)-diet-fed mice. The results demonstrated that an HF diet supplemented with BRR or GBR comparably increased the abundance of fecal isobutyric acid compared to that in mice receiving HF+white rice (WHR) diet (p < 0.01). The abundance of valeric acid in HF+GBR-diet-fed mice was higher than those receiving HF+WHR diet (p < 0.05). The abundances of fecal isobutyric acid negatively correlated with fasting plasma glucose, insulin, cholesterol, triglycerides, tumor necrosis factor-α, plasminogen activator inhibit-1, monocyte chemotactic protein-1 and homeostatic model assessment of insulin resistance (p < 0.01). The abundance of valeric acids negatively correlated with insulin resistance (p < 0.05). The abundances of isobutyric acid positively correlated with Lactobacillus, but negatively correlated with Dubosiella genus bacteria (p < 0.05). The findings demonstrated that the increases in SCFAs in the feces of BRR and GBR-treated mice were associated with improvements in gut microbiome, metabolic and inflammatory profile, which may contribute to the antidiabetic and anti-inflammatory effects of the whole grains in HF-diet-fed mice.

Degenerative Cervical Myelopathy induces sex-specific dysbiosis in mice

Degenerative Cervical Myelopathy (DCM) is the most common cause of spinal cord impairment in elderly populations. It describes a spectrum of disorders that cause progressive spinal cord compression, neurological impairment, loss of bladder and bowel functions, and gastrointestinal dysfunction. The gut microbiota has been recognized as an environmental factor that can modulate both the function of the central nervous system and the immune response through the microbiota-gut-brain axis. Changes in gut microbiota composition or microbiota-producing factors have been linked to the progression and development of several pathologies. However, little is known about the potential role of the gut microbiota in the pathobiology of DCM. Here, DCM was induced in C57BL/6 mice by implanting an aromatic polyether material underneath the C5-6 laminae. The extent of DCM-induced changes in microbiota composition was assessed by 16S rRNA sequencing of the fecal samples. The immune cell composition was assessed using flow cytometry. To date, several bacterial members have been identified using BLAST against the largest collection of metagenome-derived genomes from the mouse gut. In both, female and males DCM caused gut dysbiosis compared to the sham group. However, dysbiosis was more pronounced in males than in females, and several bacterial members of the families Lachnospiraceae and Muribaculaceae were significantly altered in the DCM group. These changes were also associated with altered microbe-derived metabolic changes in propionate-, butyrate-, and lactate-producing bacterial members. Our results demonstrate that DCM causes dynamic changes over time in the gut microbiota, reducing the abundance of butyrate-producing bacteria, and lactate-producing bacteria to a lesser extent. Genome-scale metabolic modeling using gapseq successfully identified pyruvate-to-butanoate and pyruvate-to-propionate reactions involving genes such as Buk and ACH1, respectively. These results provide a better understanding of the sex-specific molecular effects of changes in the gut microbiota on DCM pathobiology.

Alterations of lower respiratory tract microbiome and short-chain fatty acids in different segments in lung cancer: a multiomics analysis

Introduction

The lower respiratory tract microbiome is widely studied to pinpoint microbial dysbiosis of diversity or abundance that is linked to a number of chronic respiratory illnesses. However, it is vital to clarify how the microbiome, through the release of microbial metabolites, impacts lung health and oncogenesis.

Methods

In order to discover the powerful correlations between microbial metabolites and disease, we collected, under electronic bronchoscopy examinations, samples of paired bronchoalveolar lavage fluids (BALFs) from tumor-burden lung segments and ipsilateral non-tumor sites from 28 lung cancer participants, further performing metagenomic sequencing, short-chain fatty acid (SCFA) metabolomics, and multiomics analysis to uncover the potential correlations of the microbiome and SCFAs in lung cancer.

Results

In comparison to BALFs from normal lung segments of the same participant, those from lung cancer burden lung segments had slightly decreased microbial diversity in the lower respiratory tract. With 18 differentially prevalent microbial species, including the well-known carcinogens Campylobacter jejuni and Nesseria polysaccharea, the relative species abundance in the lower respiratory tract microbiome did not significantly differ between the two groups. Additionally, a collection of commonly recognized probiotic metabolites called short-chain fatty acids showed little significance in either group independently but revealed a strong predictive value when using an integrated model by machine learning. Multiomics also discovered particular species related to SCFAs, showing a positive correlation with Brachyspira hydrosenteriae and a negative one with Pseudomonas at the genus level, despite limited detection in lower airways. Of note, these distinct microbiota and metabolites corresponded with clinical traits that still required confirmation.

Conclusions

Further analysis of metagenome functional capacity revealed that genes encoding environmental information processing and metabolism pathways were enriched in the lower respiratory tract metagenomes of lung cancer patients, further supporting the oncogenesis function of various microbial species by different metabolites. These findings point to a potent relationship between particular components of the integrated microbiota-metabolites network and lung cancer, with implications for screening and diagnosis in clinical settings.

Gut Microbiota and Derived Short-Chain Fatty Acids Are Linked to Evolution of Heart Failure Patients

There is a lack of direct evidence regarding gut microbiota dysbiosis and changes in short-chain fatty acids (SCFAs) in heart failure (HF) patients. We sought to assess any association between gut microbiota composition, SCFA production, clinical parameters, and the inflammatory profile in a cohort of newly diagnosed HF patients. In this longitudinal prospective study, we enrolled eighteen newly diagnosed HF patients. At admission and after 12 months, blood samples were collected for the assessment of proinflammatory cytokines, monocyte populations, and endothelial dysfunction, and stool samples were collected for analysis of gut microbiota composition and quantification of SCFAs. Twelve months after the initial HF episode, patients demonstrated improved clinical parameters and reduced inflammatory state and endothelial dysfunction. This favorable evolution was associated with a reversal of microbiota dysbiosis, consisting of the increment of health-related bacteria, such as genus Bifidobacterium, and levels of SCFAs, mainly butyrate. Furthermore, there was a decrease in the abundance of pathogenic bacteria. In vitro, fecal samples collected after 12 months of follow-up exhibited lower inflammation than samples collected at admission. In conclusion, the favorable progression of HF patients after the initial episode was linked to the reversal of gut microbiota dysbiosis and increased SCFA production, particularly butyrate. Whether restoring butyrate levels or promoting the growth of butyrate-producing bacteria could serve as a complementary treatment for these patients deserves further studies.

The Importance of Dietary Fiber for Metabolic Health

Dietary fiber are non-digestible carbohydrates that are diverse, have varied functions, and are acquired by consuming plant-based foods. Some forms of fiber are digested by the gut microbiota and produce bioactive metabolites called short chain fatty acids-butyrate, acetate, and propionate. Dietary fiber is able to alter human physiology through multiple mechanisms that can result in health benefits. Unfortunately, nearly 19 out of 20 Americans do not consume the minimum recommended amount of fiber each day. This bears profound relevance to public health because at least six of the ten leading causes of death are potentially preventable or clinically improved through dietary means. Additionally, these same conditions share a common underlying pathophysiology-metabolic dysfunction. This can manifest as abdominal obesity, high blood pressure, insulin resistance, dyslipidemia, or collectively as metabolic syndrome. In this review, we will assess the evidence that consumption of dietary fiber undermines these forms of metabolic dysfunction, examine the mechanism of action for these physiologic effects, and consider the potential for dietary fiber to improve human health on a public health level by simply encouraging our patients to consume more plant-based foods in abundance and diversity.

[Repairing effects of Lactobacillus acidophilus on ceftriaxone-induced intestinal dysbacteriosis in mice]

OBJECTIVE

To investigate the repairing effect of Lactobacillus acidophilus LA11-Only on ceftriaxone induced intestinal micronbiota imbalance in mice and its alleviating effect on lipid metabolism.

METHODS

A total of 30 SPF BALB/c male mice were randomly divided into control group(10) and model group(20). The model group was given ceftriaxone sodium solution by gavage for a week to create a mouse model of antibiotic flora disorder. The natural recovery group(10) was given 10% skimmed milk solution by gavage, and the LA11-Onlly group was given Lactobacillus acidophilus skimmed milk solution(1.0×10~9CFU/mL). Two weeks later, the feces were collected aseptically.16S rRNA sequencing technology and ultra-high-performance liquid chromatography combined with mass spectrometry(UPLC-MS) were used to analyze the repair effect of LA11-Onlly on antibiotic induced bacterial flora disorder and lipid metabolism in mice.

RESULTS

After ceftriaxone treatment, the diversity of intestinal microbiota in mice decreased, and there was a significant difference in the composition of flora compared with the control group; After treatment with LA11-Onlly, the Alpha diversity increased, the abundance of beneficial bacteria such as Lactobacillus and Butyricicoccus increased, and the composition of flora was closer to the control group; At the same time, the concentration of short chain fatty acids(SCFAs) increased in varying degrees. Compared with the natural recovery group, the levels of butyric acid and valeric acid in LA11-Onlly group increased significantly, close to the same level as the control group.

CONCLUSION

Lactobacillus acidophilus LA11-Onlly probiotics can inhibit the growth of harmful bacteria by regulating the diversity and community composition of intestinal microbiota, promote the increase of the concentration of SCFAs, and alleviate the damage of antibiotics to the body.

Screening of Potential Probiotic Lactobacillaceae and Their Improvement of Type 2 Diabetes Mellitus by Promoting PI3K/AKT Signaling Pathway in db/db Mice

The study aimed to isolate Lactobacillaceae strains with in vitro hypoglycemic activity and probiotic properties and to determine their antidiabetic abilities in vivo. Lactiplantibacillus plantarum 22, L. plantarum 25, Limosilactobacillus fermentum 11, and L. fermentum 305 with high in vitro hypoglycemic activity were screened from 23 strains of Lactobacillaceae isolated from human feces and identified by 16S rDNA sequencing. The fasting blood glucose (FBG) of the mice was recorded weekly. After 12 weeks, liver, kidney, and pancreas tissues were stained with hematoxylin and eosin (H&E) to observe histomorphology; the inflammatory factors were assayed by Quantitative Real-time PCR; PI3K and AKT were measured by Western blot; the short-chain fatty acids (SCFAs) were determined by LC-MS/MS. Inhibitory activities of L. plantarum 22, L. plantarum 25, L. fermentum 11, and L. fermentum 305 against α-amylase were 62.29 ± 0.44%, 51.81 ± 3.65%, 58.40 ± 1.68%, and 57.48 ± 5.04%, respectively. Their inhibitory activities to α-glucosidase were 14.89 ± 0.38%, 15.32 ± 0.89%, 52.63 ± 3.07%, and 51.79 ± 1.13%, respectively. Their survival rate after simulated gastrointestinal test were 12.42 ± 2.84%, 9.10 ± 1.12%, 5.86 ± 0.52%, and 8.82 ± 2.50% and their adhesion rates to Caco-2 cell were 6.09 ± 0.39%, 6.37 ± 0.28%, 6.94 ± 0.27%, and 6.91 ± 0.11%, respectively. The orthogonal tests of bacterial powders of the four strains showed that the maximum inhibitory activities to α-amylase and α-glucosidase were 93.18 ± 1.19% and 75.33 ± 2.89%, respectively. The results showed that the mixture of Lactobacillaceae could lower FBG, reduce inflammation, and liver, kidney, and pancreas damage, promote PI3K/AKT signaling pathway, and increase the content of SCFAs. The combination of L. plantarum 22, L. plantarum 25, L. fermentum 11, and L. fermentum 305 can potentially improve type 2 diabetes mellitus (T2DM).

Sodium butyrate facilitates CRHR2 expression to alleviate HPA axis hyperactivity in autism-like rats induced by prenatal lipopolysaccharides through histone deacetylase inhibition

Short-chain fatty acids (SCFAs, especially butyric acid) have been demonstrated to play a promising role in the development of autism spectrum disorders (ASD). Recently, the hypothalamic-pituitary-adrenal (HPA) axis is also suggested to increase the risk of ASD. However, the mechanism underlying SCFAs and HPA axis in ASD development remains unknown. Here, we show that children with ASD exhibited lower SCFA concentrations and higher cortisol levels, which were recaptured in prenatal lipopolysaccharide (LPS)-exposed rat model of ASD. These offspring also showed decreased SCFA-producing bacteria and histone acetylation activity as well as impaired corticotropin-releasing hormone receptor 2 (CRHR2) expression. Sodium butyrate (NaB), which can act as histone deacetylases inhibitors, significantly increased histone acetylation at the CRHR2 promoter in vitro and normalized the corticosterone as well as CRHR2 expression level in vivo. Behavioral assays indicated ameliorative effects of NaB on anxiety and social deficit in LPS-exposed offspring. Our results imply that NaB treatment can improve ASD-like symptoms via epigenetic regulation of the HPA axis in offspring; thus, it may provide new insight into the SCFA treatment of neurodevelopmental disorders like ASD. IMPORTANCE Growing evidence suggests that microbiota can affect brain function and behavior through the "microbiome-gut-brain'' axis, but its mechanism remains poorly understood. Here, we show that both children with autism and LPS-exposed rat model of autism exhibited lower SCFA concentrations and overactivation of HPA axis. SCFA-producing bacteria, Lactobacillus, might be the key differential microbiota between the control and LPS-exposed offspring. Interestingly, NaB treatment contributed to the regulation of HPA axis (such as corticosterone as well as CRHR2) and improvement of anxiety and social deficit behaviors in LPS-exposed offspring. The potential underlying mechanism of the ameliorative effect of NaB may be mediated via increasing histone acetylation to the CRHR2 promoter. These results enhance our understanding of the relationship between the SCFAs and the HPA axis in the development of ASD. And gut microbiota-derived SCFAs may serve as a potential therapeutic agent to neurodevelopmental disorders like ASD.

Calcium-Sensitive Receptors Alters Intestinal Microbiota Metabolites Especially SCFAs and Ameliorates Intestinal Barrier Damage in Neonatal Rat Endotoxemia

Purpose

The calcium-sensing receptor (CaSR) acts as a major modulator of tissue responses related to calcium homeostasis and expresses highly in the mammalian intestine. Endotoxemia tends to impair intestinal barrier function and poses significant obstacles in clinical treatment. This work is designed to decipher whether CaSR can protect lipopolysaccharide (LPS)-induced intestinal barrier dysfunction in neonatal rats by targeting intestinal metabolites.

Patient and Methods

In this study, we utilized gas chromatography (GC) combined with liquid chromatography-mass spectrometry (LC-MS) to quantitatively analyze SCFAs and metabolites in fecal samples of 24 neonatal rats with LPS induced endotoxemia.

Results

Our results showed that CaSR alleviated endotoxin damage to the intestinal tight junction structure and upregulated the levels of butyric acid, propionic acid, valeric acid, and isovaleric acid in short-chain fatty acids (SCFAs). Non-targeted metabolomics analysis indicated that CaSR improved intestinal metabolic disorders by regulating glycerophospholipid metabolism, α-linolenic acid metabolism, as well as sphingolipids metabolism.

Conclusion

CaSR can alter intestinal microbiota metabolites, especially SCFAs, and improve intestinal barrier damage in neonatal rat endotoxemia.

Prebiotics Progress Shifts in the Intestinal Microbiome That Benefits Patients with Type 2 Diabetes Mellitus

Hypoglycemic medications that could be co-administered with prebiotics and functional foods can potentially reduce the burden of metabolic diseases such as Type 2 Diabetes Mellitus (T2DM). The efficacy of drugs such as metformin and sulfonylureas can be enhanced by the activity of the intestinal microbiome elaborated metabolites. Functional foods such as prebiotics (e.g., oligofructose) and dietary fibers can treat a dysbiotic gut microbiome by enhancing the diversity of microbial niches in the gut. These beneficial shifts in intestinal microbiome profiles include an increased abundance of bacteria such as Faecalibacterium prauznitzii, Akkermancia muciniphila, Roseburia species, and Bifidobacterium species. An important net effect is an increase in the levels of luminal SCFAs (e.g., butyrate) that provide energy carbon sources for the intestinal microbiome in cross-feeding activities, with concomitant improvement in intestinal dysbiosis with attenuation of inflammatory sequalae and improved intestinal gut barrier integrity, which alleviates the morbidity of T2DM. Oligosaccharides administered adjunctively with pharmacotherapy to ameliorate T2DM represent current plausible treatment modalities.

Sodium Butyrate as Key Regulator of Mitochondrial Function and Barrier Integrity of Human Glomerular Endothelial Cells

The gut microbiota has emerged as an important modulator of cardiovascular and renal homeostasis. The composition of gut microbiota in patients suffering from chronic kidney disease (CKD) is altered, where a lower number of bacteria producing short chain fatty acids (SCFAs) is observed. It is known that SCFAs, such as butyrate and acetate, have protective effects against cardiovascular diseases and CKD but their mechanisms of action remain largely unexplored. In the present study, we investigated the effect of butyrate and acetate on glomerular endothelial cells. Human glomerular microvascular endothelial cells (hgMVECs) were cultured and exposed to butyrate and acetate and their effects on cellular proliferation, mitochondrial mass and metabolism, as well as monolayer integrity were studied. While acetate did not show any effects on hgMVECs, our results revealed that butyrate reduces the proliferation of hgMVECs, strengthens the endothelial barrier through increased expression of VE-cadherin and Claudin-5 and promotes mitochondrial biogenesis. Moreover, butyrate reduces the increase in oxygen consumption induced by lipopolysaccharides (LPS), revealing a protective effect of butyrate against the detrimental effects of LPS. Taken together, our data show that butyrate is a key player in endothelial integrity and metabolic homeostasis.

Recent Advances in Microbiota-Associated Metabolites in Heart Failure

Heart failure is a risk factor for adverse events such as sudden cardiac arrest, liver and kidney failure and death. The gut microbiota and its metabolites are directly linked to the pathogenesis of heart failure. As emerging studies have increased in the literature on the role of specific gut microbiota metabolites in heart failure development, this review highlights and summarizes the current evidence and underlying mechanisms associated with the pathogenesis of heart failure. We found that gut microbiota-derived metabolites such as short chain fatty acids, bile acids, branched-chain amino acids, tryptophan and indole derivatives as well as trimethylamine-derived metabolite, trimethylamine N-oxide, play critical roles in promoting heart failure through various mechanisms. Mainly, they modulate complex signaling pathways such as nuclear factor kappa-light-chain-enhancer of activated B cells, Bcl-2 interacting protein 3, NLR Family Pyrin Domain Containing inflammasome, and Protein kinase RNA-like endoplasmic reticulum kinase. We have also highlighted the beneficial role of other gut metabolites in heart failure and other cardiovascular and metabolic diseases.

Water-Insoluble Polysaccharide Extracted from Poria cocos Alleviates Antibiotic-Associated Diarrhea Based on Regulating the Gut Microbiota in Mice

Antibiotics are very effective in treating a variety of bacterial infections, while clinical overuse of antibiotics can lead to diseases such as antibiotic-associated diarrhea. Numerous studies have shown that natural polysaccharides can be used as prebiotics to alleviate antibiotic-associated diarrhea (AAD). Poria cocos is a medicinal and edible mushroom widely used for thousands of years in China, and our former study demonstrated that water-insoluble polysaccharide (PCY) has the potential prebiotic function. Therefore, we simulated the digestion and fermentation of PCY using feces from volunteers, and then administered it to C57BL/6 mice with AAD to study its effects on the gut microbiota and metabolites. The results indicated that PCY effectively alleviated the symptoms of AAD in mice, restored the intestinal barrier function, improved the content of short-chain fatty acids (SCFAs), decreased the level of inflammatory cytokines, and changed the structure of gut microbiota by increasing the relative abundance of norank_f__Muribaculaceae and unclassified_f__Lachnospiraceae, and decreasing that of Escherichia-Shigella, Staphylococcus and Acinetobacter. This study further demonstrated that PCY is an effective functional prebiotic for improving AAD disease, and provided a new avenue and insight for developing PCY as a functional food or prebiotic for alleviating gastrointestinal diseases.

Postbiotics in oncology: science or science fiction?

The gut microbiome has been increasingly understood to play a critical role in carcinogenesis and cancer disease progression. The most recent research advancements have shown that different tools of microbiota manipulation contribute to gut microbiome-immune-oncology axis modulation, offering exciting opportunities for targeted interventions aimed at improving the efficacy of established anti-cancer therapy. Postbiotics are a new entry among the biotics showing beneficial effects on human health while not requiring living cells to obtain the health effect and therefore not subjected to food safety rules for live microorganisms. Postbiotics are recently defined as the "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host" and have gradually become the focus of the scientific community. Since the beginning of research on this topic, numerous studies about postbiotics have been proven to strengthen the gut barrier, reduce inflammation, and promote antimicrobial activity. However, research on the potential application of cancer therapy is still at the early stages of its efforts to uncover all the secrets surrounding postbiotics. This review aims to increase our understanding of the anti-cancer effect of postbiotics throughout a "bibliographic journey" on the biological activity of their components, including exopolysaccharides, cell wall fragments, tryptophan metabolites, enzymes, bacterial lysates, extracellular vesicles, and short-chain fatty acids, highlighting their perspective as a new supportive therapeutic method of treatment and identifying the literature gaps where further research is needed.

Scientific Evidence for the Beneficial Effects of Dietary Blueberries on Gut Health: A Systematic Review

Emerging evidence indicates the association between an unhealthy gut and chronic diseases. A healthy gut comprises an intact gut epithelium and balanced gut microbes. Diet is one of the critical factors that modulate gut health by positively or negatively affecting the intestinal barrier and gut microbes. Blueberries are an excellent source of health-promoting bioactive components, and this systematic review is conducted to evaluate the effect of dietary blueberries on gut health. A literature search is conducted on PubMed/MEDLINE, Scopus, Web of Science, and Embase databases to review relevant studies published between 2011 and 2022 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Systematic Review Center for Laboratory Animal Experimentation Risk of Bias (SYRCLE-RoB) tool is used for methodological quality assessments. Sixteen studies included from four countries are reviewed and the results are synthesized narratively. This data analysis indicates that blueberry supplementation improves gut health by improving intestinal morphology, reducing gut permeability, suppressing oxidative stress, ameliorating gut inflammation, and modulating the composition and function of gut microbes. However, there are significant knowledge gaps in this field. These findings indicate that further studies are needed to establish the beneficial effects of blueberries on gut health.

The Impact of a 24-h Low and High Fermentable Oligo- Di- Mono-Saccharides and Polyol (FODMAP) Diet on Plasma Bacterial Profile in Response to Exertional-Heat Stress

Exertional-heat stress (EHS) compromises intestinal epithelial integrity, potentially leading to the translocation of pathogenic agents into circulation. This study aimed to explore the impact of EHS on the systemic circulatory bacterial profile and to determine the impact of a short-term low (LFOD) and high (HFOD) fermentable oligo- di- mono-saccharide and polyol dietary intervention before EHS on this profile. Using a double-blind randomized cross-over design, thirteen endurance runners (n = 8 males, n = 5 females), with a history of exercise-associated gastrointestinal symptoms (Ex-GIS), consumed a 24 h LFOD and HFOD before 2 h running at 60% V.O2max in 35.6 °C. Blood and fecal samples were collected pre-EHS to determine plasma microbial DNA concentration, and sample bacteria and short chain fatty acid (SCFA) profiles by fluorometer quantification, 16S rRNA amplicon gene sequencing, and gas chromatography, respectively. Blood samples were also collected post-EHS to determine changes in plasma bacteria. EHS increased plasma microbial DNA similarly in both FODMAP trials (0.019 ng·μL-1 to 0.082 ng·μL-1) (p < 0.01). Similar pre- to post-EHS increases in plasma Proteobacteria (+1.6%) and Firmicutes (+0.6%) phyla relative abundance were observed in both FODMAP trials. This included increases in several Proteobacteria genus (Delftia and Serratia) groups. LFOD presented higher fecal Firmicutes (74%) and lower Bacteroidota (10%) relative abundance pre-EHS, as a result of an increase in Ruminococcaceae and Lachnospiraceae family and respective genus groups, compared with HFOD (64% and 25%, respectively). Pre-EHS plasma total SCFA (p = 0.040) and acetate (p = 0.036) concentrations were higher for HFOD (188 and 178 μmol·L-1, respectively) vs. LFOD (163 and 153 μmol·L-1, respectively). Pre-EHS total fecal SCFA concentration (119 and 74 μmol·g-1; p < 0.001), including acetate (74 and 45 μmol·g-1; p = 0.001), butyrate (22 and 13 μmol·g-1; p = 0.002), and propionate (20 and 13 μmol·g-1; p = 0.011), were higher on HFOD vs LFOD, respectively. EHS causes the translocation of whole bacteria into systemic circulation and alterations to the plasma bacterial profile, but the FODMAP content of a 24 h diet beforehand does not alter this outcome.

The benefits of edible mushroom polysaccharides for health and their influence on gut microbiota: a review

The gut microbiome is a complex biological community that deeply affects various aspects of human health, including dietary intake, disease progression, drug metabolism, and immune system regulation. Edible mushroom polysaccharides (EMPs) are bioactive fibers derived from mushrooms that possess a range of beneficial properties, including anti-tumor, antioxidant, antiviral, hypoglycemic, and immunomodulatory effects. Studies have demonstrated that EMPs are resistant to human digestive enzymes and serve as a crucial source of energy for the gut microbiome, promoting the growth of beneficial bacteria. EMPs also positively impact human health by modulating the composition of the gut microbiome. This review discusses the extraction and purification processes of EMPs, their potential to improve health conditions by regulating the composition of the gut microbiome, and their application prospects. Furthermore, this paper provides valuable guidance and recommendations for future studies on EMPs consumption in disease management.

Age-related effects on the modulation of gut microbiota by pectins and their derivatives: an in vitro study

Introduction

The present study investigates whether supplementation with pectin-type polysaccharides has potential to improve aging-associated dysbiosis of the gut microbiota. The influence of different types of pectins on the gut microbiota composition and short-chain fatty acids (SCFAs) profiles of elderly was compared to younger adults.

Methods

Pectins studied included a pectin polysaccharide (PEC), a partially hydrolyzed pectin (PPH), and a pectin oligosaccharide (POS). Additionally, inulin was used as a reference prebiotic substrate. Individual fecal samples were collected from healthy elderly volunteers (70-75 years) and younger adults (30-35 years). In vitro fermentations were performed using the CoMiniGut model with controlled temperature and pH. Samples were withdrawn at baseline and after 24 h fermentation for measurement of SCFAs production and microbiota composition by 16S rRNA gene sequencing.

Results and Discussion

The results showed that fermentations with PEC and PPH resulted in a specific stimulation of Faecalibacterium prausnitzii regardless of the age groups. Collinsella aerofaciens became a dominating species in the young adult group with fermentations of all three pectins, which was not observed in the elderly group. No significant differences in SCFAs production were found among the pectins, indicating a high level of functional redundancy. Pectins boosted various bacterial groups differently from the reference prebiotic substrate (inulin). We also found inulin had reduced butyrogenic and bifidogenic effects in the elderly group compared to the younger adult group. In conclusion, the in vitro modulating effects of pectins on elderly gut microbiota showed potential of using pectins to improve age-related dysbiosis.