High-Throughput RPLC-MS/MS Quantification of Short- and Medium-Chain Fatty Acids.

Short- and medium-chain fatty acids (SMCFA) are monocarboxylic acids with a carbon chain length of 1-12 carbon atoms. They are mainly produced in humans by the gut microbiota, play crucial metabolic roles, are vital for intestinal health, and have multifaceted impact on immune and neurological functions. Accurate detection and quantification of SMCFA in different human biofluids is achieved using 3-nitro phenylhydrazine (3-NPH) derivatization of the free fatty acids followed by reverse phase liquid chromatography (RPLC) separation and detection by tandem mass spectrometry (MS/MS). Here, we describe the simultaneous measurement of 14 SMCFA and lactate in detail. All 3-NPH-SMCFA-hydrazones are separated in less than 5 min with an 8-min total run time (injection-to-injection). Linear dynamic range over 0.1-500 µM is achieved for most SCFAs, while it is 0.05-100 µM for MCFAs. Validation of the procedure depicts good linearity (R2 > 0.98) and repeatability (CV ≤ 20%). The lower limit of detection (LLOD) is 10-30 nM. The lower limit of quantification (LLOQ) is 50-100 nM for most analytes, while it is 0.5 µM for acetate. In conclusion, the method offers several benefits compared to alternative methods regarding throughput, selectivity, sensitivity, and robustness.

Suppression of certain intestinal microbiota metabolites may lead to gestational diabetes in mice fed a high-fat diet.

Background: We aim to establish a gestational diabetes mellitus (GDM) mouse model with mice fed with a high-fat diet (HFD) in comparison with pregnant mice with normal blood glucose levels to investigate the role of intestinal microbiota in the development of HFD-induced GDM. Methods: We divided healthy 6-week-old female C57BL mice into an HFD-induced GDM group and a normal diet group. Their bacterial flora and metabolites in intestinal fecal exosomes were co-analyzed using 16 s multi-region sequencing and compared. Findings: Alpha (α) diversity was lower within the model group compared to the control group. Beta (ß) diversity was significantly different between the two groups. The relative abundances of Lactobacillus, Actinomyces, Rothia, and Bacteroidetes were significantly different between the two groups. Fermentation and nitrate consumption were significantly higher in the GDM group. Multiple bacteria were associated with glycerophosphocholine, S-methyl-5'-thioadenosine, quinolinate, galactinol, deoxyadenosine, DL-arginine, and 2-oxoadenic acid. Interpretation: Imbalances in the production of Lactobacillus, Bacteroidetes, Actinomyces, and Rothia and their related metabolites may lead to metabolic disturbances in GDM. These indicators may be used to assess changes affecting the intestinal microbiota during pregnancy and thus help modulate diet and alter blood glucose.

Microbes and mood: innovative biomarker approaches in depression.

Although the field of psychiatry has made gains in biomarker discovery, our ability to change long-term outcomes remains inadequate. Matching individuals to the best treatment for them is a persistent clinical challenge. Moreover, the development of novel treatments has been hampered in part due to a limited understanding of the biological mechanisms underlying individual differences that contribute to clinical heterogeneity. The gut microbiome has become an area of intensive research in conditions ranging from metabolic disorders to cancer. Innovation in these spaces has led to translational breakthroughs, offering novel microbiome-informed approaches that may improve patient outcomes. In this review we examine how translational microbiome research is poised to advance biomarker discovery in mental health, with a focus on depression.

Gut microbiome features in pediatric food allergy: a scoping review.

Increasing evidence suggests that alterations in the gut microbiome (GM) play a pivotal role in the pathogenesis of pediatric food allergy (FA). This scoping review analyzes the current evidence on GM features associated with pediatric FAs and highlights the importance of the GM as a potential target of intervention for preventing and treating this common condition in the pediatric age. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we searched PubMed and Embase using the keywords (gut microbiome OR dysbiosis OR gut microbiota OR microbiome signatures) AND (food allergy OR IgE-mediated food allergy OR food protein-induced allergic proctocolitis OR food protein-induced enterocolitis OR non-IgE food allergy OR cow milk allergy OR hen egg allergy OR peanut allergy OR fish allergy OR shellfish allergy OR tree nut allergy OR soy allergy OR wheat allergy OR rice allergy OR food sensitization). We included 34 studies reporting alterations in the GM in children affected by FA compared with healthy controls. The GM in pediatric FAs is characterized by a higher abundance of harmful microorganisms (e.g., Enterobacteriaceae, Clostridium sensu stricto, Ruminococcus gnavus, and Blautia spp.) and lower abundance of beneficial bacteria (e.g., Bifidobacteriaceae, Lactobacillaceae, some Bacteroides species). Moreover, we provide an overview of the mechanisms of action elicited by these bacterial species in regulating immune tolerance and of the main environmental factors that can modulate the composition and function of the GM in early life. Altogether, these data improve our knowledge of the pathogenesis of FA and can open the way to innovative diagnostic, preventive, and therapeutic strategies for managing these conditions.

From gut to bone: deciphering the impact of gut microbiota on osteoporosis pathogenesis and management.

Osteoporosis (OP) is characterized by decreased bone mineral density (BMD) and increased fracture risk, poses a significant global health burden. Recent research has shed light on the bidirectional relationship between gut microbiota (GM) and bone health, presenting a novel avenue for understanding OP pathogenesis and developing targeted therapeutic interventions. This review provides a comprehensive overview of the GM-bone axis, exploring the impact of GM on OP development and management. We elucidate established risk factors and pathogenesis of OP, delve into the diversity and functional changes of GM in OP. Furthermore, we examine experimental evidence and clinical observations linking alterations in GM composition or function with variations in BMD and fracture risk. Mechanistic insights into microbial mediators of bone health, such as microbial metabolites and products, are discussed. Therapeutic implications, including GM-targeted interventions and dietary strategies, are also explored. Finally, we identify future research directions and challenges in translating these findings into clinical practice.

The role of gut microbiota in prostate inflammation and benign prostatic hyperplasia and its therapeutic implications.

Background: The gut microbiota thrives in a complex ecological environment and its dynamic balance is closely related to host health. Recent studies have shown that the occurrence of various diseases including prostate inflammation is related to the dysregulation of the gut microbiome. Objective: This review focus on the mechanisms by which the gut microbiota induces prostate inflammation and benign prostatic hyperplasia and its therapeutic implications. Materials and methods: Publications related to gut microbiota, prostate inflammation, and benign prostatic hyperplasia (BPH) until April 2023 were systematically reviewed. The research questions were formulated using the Problem, Intervention, Comparison/Control, and Outcome (PICO) frameworks. Results: Fifteen articles covering the relationship between the gut microbiota and prostate inflammation/BPH, the mechanisms by which the gut microbiota influences prostate inflammation and BPH, and potential therapeutic approaches targeting the gut microbiota for these conditions were included. Conclusion: Short-chain fatty acids (SCFAs), which are metabolites of the intestinal microbiota, protect the integrity of the intestinal barrier, regulate immunity, and inhibit inflammation. However, dysregulation of the gut microbiota significantly reduces the SCFA content in feces and impairs the integrity of the gut barrier, leading to the translocation of bacteria and bacterial components such as lipopolysaccharide, mediating the development of prostate inflammation through microbe-associated molecular patterns (MAMPs).

Propionate Decreases Microglial Activation but Impairs Phagocytic Capacity in Response to Aggregated Fibrillar Amyloid Beta Protein.

Microglia, the innate immune cell of the brain, are a principal player in Alzheimer's disease (AD) pathogenesis. Their surveillance of the brain leads to interaction with the protein aggregates that drive AD pathogenesis, most notably Amyloid Beta (Aß). Microglia attempt to clear and degrade Aß using phagocytic machinery, spurring damaging neuroinflammation in the process. Thus, modulation of the microglial response to Aß is crucial in mitigating AD pathophysiology. SCFAs, microbial byproducts of dietary fiber fermentation, are blood-brain barrier permeable molecules that have recently been shown to modulate microglial function. It is unclear whether propionate, one representative SCFA, has beneficial or detrimental effects on microglia in AD. Thus, we investigated its impact on microglial Aß response in vitro. Using a multiomics approach, we characterized the transcriptomic, metabolomic, and lipidomic responses of immortalized murine microglia following 1 h of Aß stimulation, as well as characterizing Aß phagocytosis and secretion of reactive nitrogen species. Propionate blunted the early inflammatory response driven by Aß, downregulating the expression of many Aß-stimulated immune genes, including those regulating inflammation, the immune complement system, and chemotaxis. Further, it reduced the expression of Apoe and inflammation-promoting Aß-binding scavenger receptors such as Cd36 and Msr1 in favor of inflammation-dampening Lpl, although this led to impaired phagocytosis. Finally, propionate shifted microglial metabolism, altering phospholipid composition and diverting arginine metabolism, resulting in decreased nitric oxide production. Altogether, our data demonstrate a modulatory role of propionate on microglia that may dampen immune activation in response to Aß, although at the expense of phagocytic capacity.

Examining the complex Interplay between gut microbiota abundance and short-chain fatty acid production in amyotrophic lateral sclerosis patients shortly after onset of disease.

This study aimed to assess differences in the enteral microbiome of relatively recent-onset amyotrophic lateral sclerosis (ALS) patients (< 6-15 months since symptom onset) compared to healthy individuals, focusing on short-chain fatty acids (SCFAs) as potential mediators of host metabolism. We included 28 volunteers (16 ALS, 12 controls) with informed consent. No significant effect of ALS on alpha diversity (measuring the variety and abundance of species within a single sample, and indicating the health and complexity of the microbiome) was observed, but ALS patients had higher abundances of Fusobacteria and Acidobacteria. ALS subtypes influenced specific species, with increased Fusobacteria and Tenericutes in spinal ALS compared to bulbar ALS. ALS patients showed increased Enterobacter, Clostridium, Veillonella, Dialister, Turicibacter, and Acidaminococcus species and decreased Prevotella, Lactobacillus, and Butyricimonas. Correlations between species varied between ALS patients and healthy individuals and among ALS subtypes. No significant differences in SCFA concentrations were found, but spinal ALS samples showed a trend towards decreased propionate content. Relationships between SCFAs and phyla colonization differed by disease status. This study suggests distinct enteral microbiome characteristics in ALS patients, though the implications are unclear. Further research is needed to determine if these differences are causative or consequential and to explore their potential as diagnostic or therapeutic targets. The study also underscores the heterogeneity of microbiome constraints in ALS and the need for more research into ALS and SCFA metabolism.

Increasing degree of substitution inhibits acetate while promotes butyrate production during in vitro fermentation of citric acid-modified rice starch.

Citric acid-modified starch functions as a resistant starch, while the combined effects of its fine molecular structure and degree of substitution on gut microbiota are not well understood. To this end, citric acid-modified starches with varying degrees of substitution were synthesized from rice starches with distinct molecular structures and their impact on gut microbiota composition and short-chain fatty acid (SCFA) production was analyzed. Notably, rice starch with a higher degree of substitution significantly reduced acetate production, while promoted butyrate production. Correlation analysis further suggested that amylopectin chains with 12 < DP ≤ 36 and amylose chains with 100 < DP ≤ 500 alter the growth of Faecalibacterium_prausnitzii and Bacteroides_vulgatus, consequentially determining the production of SCFAs. Collectively, these findings indicate that citric acid-modified rice starch with different degrees of substitution can target specific gut bacteria and SCFA production, thus conferring beneficial impact on human health.

The short-chain fatty acid receptors Gpr41/43 regulate bone mass by promoting adipogenic differentiation of mesenchymal stem cells.

Bone is a dynamic tissue that is constantly remodeled throughout adult life. Recently, it has been shown that bone turnover decreases shortly after food consumption. This process has been linked to the fermentation of non-digestible food ingredients such as inulin by gut microbes, which results in the production of the short-chain fatty acids (SCFAs) acetate, propionate and butyrate. SCFAs exert various metabolic functions, which in part can be explained by activation of G protein-coupled receptors (Gpr) 41 and 43. However, the potential relevance of a SCFA-Gpr41/43 signaling axis for bone metabolism has not been established. The aim of our study is to investigate the role of Gpr41/43 in bone metabolism and osteogenic differentiation of mesenchymal stem cells. For this purpose, we analyzed the skeletal phenotype of wild type controls (WT) and Gpr41/43 double knockout (Gpr41/43 dKO) mice fed either a chow or an inulin-enriched diet. In addition, we isolated bone marrow derived mesenchymal stem cells from WT and Gpr41/43 dKO mice and differentiated them into osteoblasts in the absence or presence of acetate. MicroCT scanning of femoral bones of Gpr41/43 dKO mice revealed a significant increase of trabecular bone volume and trabecular compared to WT controls. Treatment of WT bone marrow-derived osteoblasts with acetate resulted in decreased mineralization and substantial downregulation of bone formation markers such as Phex, Ptgs2 and Col1a1. Notably, this effect was strongly attenuated in differentiated osteoblasts lacking Gpr41/43. Inversely, acetate supplementation resulted in higher levels of adipocyte marker genes including Pparg, Lpl and Adipoq in bone marrow-derived cells from WT mice, an effect blunted in differentiated cells isolated from Gpr41/43 dKO mice. Overall, these data indicate that acetate regulates bone architecture via SCFA-Gpr41/43 signaling by modulating the osteogenic versus adipogenic differentiation of mesenchymal stem cells.

Effect of konjac glucomannan on gut microbiota from hyperuricemia subjects in vitro: fermentation characteristics and inhibitory xanthine oxidase activity.

Background: The disorder of uric acid metabolism is closely associated with gut microbiota and short-chain fatty acids (SCFAs) dysregulation, but the biological mechanism is unclear, limiting the development of uric acid-lowering active polysaccharides. Konjac glucomannan (KGM) could attenuate metabolic disturbance of uric acid and modulate the gut microbiota. However, the relationship between uric acid metabolism and gut microbiota is still unknown. Methods: In this study, The fecal samples were provided by healthy volunteers and hyperuricemia (HUA) patients. Fecal samples from healthy volunteers was regarded as the NOR group. Similarly, 10% HUA fecal suspension was named as the HUA group. Then, fecal supernatant was inoculated into a growth basal medium containing glucose or KGM, and healthy fecal samples were designated as the NOR-GLU and NOR-KGM groups, while HUA fecal samples were designated as the HUA-GLU and HUA-KGM groups. All samples were cultured in an anaerobic bag system. After fermentation for 24 h, the samples were collected for further analysis of composition of intestinal microbiota, SCFAs concentration and XOD enzyme activity. Results: The results showed that KGM could be utilized and degraded by the gut microbiota from HUA subjects, and it could modulate the composition and structure of their HUA gut microbiota to more closely resemble that of a healthy group. In addition, KGM showed a superior modulated effect on HUA gut microbiota by increasing Megasphaera, Faecalibacterium, Lachnoclostridium, Lachnospiraceae, Anaerostipes, and Ruminococcus levels and decreasing Butyricicoccus, Eisenbergiella, and Enterococcus levels. Furthermore, the fermentation solution of KGM showed an inhibitory effect on xanthine oxidase (XOD) enzyme activity, which might be due to metabolites such as SCFAs. Conclusion: In conclusion, the effect of KGM on hyperuricemia subjects was investigated based on the gut microbiota in vitro. In the present study. It was found that KGM could be metabolized into SCFAs by HUA gut microbiota. Furthermore, KGM could modulate the structure of HUA gut microbiota. At the genus level, KGM could decrease the relative abundances of Butyricicoccus, Eisenbergiella, and Enterococcus, while Lachnoclostridium and Lachnospiraceae in HUA gut microbiota were significantly increased by the addition of KGM. The metabolites of gut microbiota, such as SCFAs, might be responsible for the inhibition of XOD activity. Thus, KGM exhibited a superior probiotic function on the HUA gut microbiota, which is expected as a promising candidate for remodeling the HUA gut microbiota.

Mechanistic insight of neurodegeneration due to micro/nano-plastic-induced gut dysbiosis.

Despite offering significant conveniences, plastic materials contribute substantially in developing environmental hazards and pollutants. Plastic trash that has not been adequately managed may eventually break down into fragments caused by human or ecological factors. Arguably, the crucial element for determining the biological toxicities of plastics are micro/nano-forms of plastics (MPs/NPs), which infiltrate the mammalian tissue through different media and routes. Infiltration of MPs/NPs across the intestinal barrier leads to microbial architectural dysfunction, which further modulates the population of gastrointestinal microbes. Thereby, it triggers inflammatory mediators (e.g., IL-1α/ß, TNF-α, and IFN-γ) by activating specific receptors located in the gut barrier. Mounting evidence indicates that MPs/NPs disrupt host pathophysiological function through modification of junctional proteins and effector cells. Moreover, the alteration of microbial diversity by MPs/NPs causes the breakdown of the blood-brain barrier and translocation of metabolites (e.g., SCFAs, LPS) through the vagus nerve. Potent penetration affects the neuronal networks, neuronal protein accumulation, acceleration of oxidative stress, and alteration of neurofibrillary tangles, and hinders distinctive communicating pathways. Conclusively, alterations of these neurotoxic factors are possibly responsible for the associated neurodegenerative disorders due to the exposure of MPs/NPs. In this review, the hypothesis on MPs/NPs associated with gut microbial dysbiosis has been interlinked to the distinct neurological impairment through the gut-brain axis.

Investigating the mechanism of enhanced medicinal effects of Terminalia chebula fruit after processing based on intestinal flora and metabolomics.

BACKGROUND AND OBJECTIVE: Terminalia chebula is a classical medicine for the treatment of lingering dysentery, and both raw and processed T. chebula can alleviate ulcerative colitis (UC). The therapeutic efficacy of T. chebula is enhanced after processing, but the mechanism that processing improves this efficacy is still unknown. We investigated the medicinal effects of raw and processed T. chebula on dextran sulfate sodium (DSS)-induced UC model rats using intestinal flora and metabolomics analyses, in order to elucidate the mechanism by which processing enhances the therapeutic effect. METHODS: The major constituents of raw and processed T. chebula were detected by high-performance liquid chromatography (HPLC). UC model was replicated using the DSS method, and then UC rats were administered raw and processed T. chebula. The general physical signs, disease activity index (DAI) scores, colon histopathological morphology, and the expressions of inflammatory cytokines were used to evaluate the therapeutic effect of T. chebula. In addition, 16 s rRNA sequencing and gas chromatography-mass spectrometry (GC-MS) were used to characterize the intestinal flora and contents of short-chain fatty acids (SCFAs). Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was utilized to identify the nontargeted fecal metabolites. RESULTS: Raw and processed T. chebula significantly improved the general physical signs and colon inflammatory symptoms and decreased DAI scores of UC rats. Both raw and processed T. chebula mitigated intestinal flora disorders in UC rats, increasing probiotic bacteria, including Lactobacillus and Romboutsia. However, the effect of processed T. chebula was more pronounced. Moreover, the levels of SCFAs of DSS-induced UC rats were restored after drug administration, and the processed T. chebula had a better regulatory effect than raw T. chebula. In the fecal nontargeted metabolomics analysis, differential metabolites such as lipids and amino acids were identified. The processed T. chebula can regulate purine metabolism and other pathways to improve UC, and the levels of the disordered metabolites gradually approached those of the control group. CONCLUSION: Raw and processed T. chebula had the capacity to mitigate DSS-induced UC by rebalancing the intestinal flora, restoring the contents of SCFAs, and regulating fecal metabolites, while processed T. chebula showed preferable effects.

Integrated gut microbiota and serum pharmacochemistry reveal the mechanisms of wine steaming in alleviating rhubarb diarrhea.

BACKGROUND: Long-term use of rhubarb (RH) can cause adverse gastrointestinal reactions (such as diarrhea), whereas RH steaming with wine (PRH) can alleviate RH-induced diarrhea. However, the potential material basis and mechanisms by which wine steaming alleviates diarrhea caused by RH remain unclear. PURPOSE: To reveal the potential material basis and underlying mechanisms of wine steaming in alleviating diarrhea caused by RH from the perspective of small intestinal flora and immune function. METHODS: The major anthraquinone/anthrone components were detected using high-performance liquid chromatography (HPLC). Constipation model mice were replicated using loperamide hydrochloride and were administered RH and PRH for six consecutive weeks. Histopathological observation (duodenum, jejunum, and ileum) was performed using hematoxylin-eosin (HE) staining, and the serum levels of inflammatory cytokines, immunoglobulin G (IgG), and immunoglobulin A (IgA) were examined. CD4+, CD8+, and Treg cells counts in peripheral blood were determined using flow cytometry; The protein expression of Toll-like receptor 4 (TLR4) and nuclear factor kappa-B (NF-κB) was determined using immunohistochemistry (IHC) and western blot (WB). The small intestine contents and feces were analyzed by 16 S rRNA sequencing and the contents of short chain fatty acids (SCFAs) in feces were determined using gas chromatography-mass spectrometry (GC-MS). Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was used to analyze the blood absorption compounds and endogenous metabolites. RESULTS: The levels of the major anthraquinone/anthrone components were decreased in PRH. RH and PRH both increased the wet fecal weight at 12 h (WFW-12) and fecal water rate (FWR), alleviated the dry and black fecal morphology, and relieved small intestine injuries in the second week. In the fourth week, although RH and PRH alleviated the abnormal levels of indicators in the model mice (fecal water rate, immune cells percentage, and TLR4/NF-κB expression), minor small intestinal damage was observed. Compared to that at the fourth week, RH and PRH increased the levels of WFW-12, FWR, inflammatory cytokines, and TLR4/NF-κB expression, and decreased the levels of IgG/IgA and immune cells with extended administration (sixth week). Further, damage to the small intestine worsened (severe ileal damage) and different degrees of loose stools were observed in RH- and PRH-administered mice in the sixth week. Compared with those in the control group, the levels of WFW-12, FWR, inflammatory cytokines, TLR4/NF-κB expression, IgG/IgA, and immune cell percentage were significantly different in the RH-H and PRH-H mice at the sixth week (except for CD8+in PRH-H). Further, RH and PRH disturbed the gut microbiota (GM) (Lactobacillus and Dubosiella decreased, Aerococcus and Corynebacterium increased) and obviously reduced the content of SCFAs (acetic acid, butyric acid, and isobutyric acid). However, almost all the results indicated a lower impact of PRH than that of RH. Metabolic pathways mainly involved in glycerophospholipid metabolism were identified along with a total of 21 blood absorption components, including anthraquinones, anthrones, flavanols, and tannins. The correlation analysis showed a positive correlation of pathogenic bacteria (Aerococcus and Corynebacterium) with inflammatory cytokines, TLR4/NF-κB, LysoPC(20:0/0:0), and PE (16:0/20:4(8Z,11Z,14Z,17Z)) and a negative correlation with immune cells and SCFAs (acetic acid and isobutyric acid); however, the opposite results were observed for beneficial bacteria (Lactobacillus and Dubosiella). CONCLUSION: Overall, PRH can alleviate RH-induced diarrhea by recovering the GM imbalance and abnormal levels of GM-mediated SCFAs, alleviating the decrease in cellular immune function and abnormal expression of TLR4/NF-κB, thereby suppressing the release of inflammatory factors, possibly, through its lower content of anthraquinones. This study explored for the first time the processing mechanism of wine steaming in alleviating RH-induced diarrhea from the aspects of small intestinal flora and small intestinal immune function.

Diethyl ethylphosphonate retardants disturbed the gut microbiome and metabolite SCFAs in vitro based on simulator of the human intestinal microbial ecosystem.

Diethyl ethylphosphonate (DEEP) as a novel organophosphorus flame retardant received increasing attention and its structure was discovered. But there are currently insufficient studies on how DEEP exposure affects the gut microbiome. In this study, the effects of DEEP on the structure and function of the human gut microbiota were examined using the SHIME system. Results from high-throughput sequencing of the 16S rRNA gene show that the high dose DEEP exposure reduced the Shannon and Simpson index in the transverse and descending colon. The Bacillota had the highest proportion while the proportion of Proteobacteria gradually decreased at the phylum level. The abundance of Escherichia, Prevotella, and Bilophila at the genus level increased with increasing doses of DEEP exposure. On the contrary, the abundance of Megasphaera, Klebsiella, and Phascolarctobacterium decreased. The short-chain fatty acids had a significant shift. With increasing doses of DEEP exposure, the concentration of acetic acid and propionic acid increased, while the concentration of butyric acid reached the highest at the medium dose of exposure. In addition, Bilophila, Psychrobacter, Escherichia, and Nostoe showed strong beneficial associations with acetic and propionic acids under DEEP exposure. Phocaeicola, Agathobacter, Klebsiella, Megasphaera, Phascolarctobacterium, and Bacteroides were negatively association with acetic and propionic acids. In a word, the study verified that exposure to different doses of DEEP can cause changes in the composition of the gut microbiome and metabolite SCFAs, which provides ideas for the investigation of other potential hazards of DEEP on human beings.

Artificial sweetener-induced dysbiosis and associated molecular signatures.

Despite their approval for inclusion in beverages, and food products, the safety of artificial sweeteners is still a topic of debate within the scientific community. A significant aspect of this debate focuses on the potential of artificial sweeteners to induce dysbiosis, an imbalance in the intestinal microbiota, which has been associated with many diseases including obesity, Type 2 diabetes, and cardiovascular diseases. The interactions and mechanisms of action of artificial sweeteners within the gut microbiota, as well as the extent of associated molecular alterations, are still under active investigation. This review aims to evaluate recent developments in artificial sweetener-induced dysbiosis with its associated molecular signatures. Importantly, potential future directions for research are proposed, offering insights that could guide further targeted studies and inform dietary recommendations and policy revisions.

Feasibility of double nitrite supply through partial nitrification and partial denitrification driven by sludge fermentation.

Challenges in obtaining stable nitrite have impeded the use of anammox in municipal wastewater treatment. This study explored the feasibility of using sludge fermentation products as carbon source and selective nitrification inhibitor to supply nitrite via partial nitrification (PN) and partial denitrification (PD). PD was initiated within 15 days, achieving nitrite transformation rate of over 90 % with a C/N ratio of 3 and a reaction time of 0.75 h. The dominant genus, Romboutsia, increased in relative abundance from 4.1 to 35 %. Organic acids in sludge fermentation products, like acetate (200 mg/L) and propionate (400 mg/L), selectively suppressed nitrite-oxidizing bacteria (NOB) more than ammonia-oxidizing bacteria (AOB), leading to PN. Combining anaerobic exposure with sludge fermentation products addition achieved PN with over 80.0 % nitrite accumulation. AOB increased tenfold in the long term, significantly outpacing NOB growth. This strategy simplifies difficulty of anammox application and shows broad application potential in municipal wastewater treatment.

Therapeutic potential of compound extract from Dracocephalum Rupestre Hance and Berberidis Radix against Salmonella-induced lamb diarrhea.

Lamb diarrhea is primarily induced by bacterial infections, causing great economic and health challenges. Traditional antibiotic treatments raise concerns over drug resistance and environmental contamination. We explored the therapeutic potential of a compound extract from Dracocephalum rupestre Hance and Berberidis Radix against Salmonella-induced diarrhea in lamb. Twenty-five five-week-old Kunming mice (20 ± 5 g) were used. A controlled laboratory experiment, combing histological examinations, serum cytokine level analysis, gut microbiota composition analysis, and short-chain fatty acid quantification were conducted. Results demonstrated significant reparative effects on intestinal mucosal damage of the compound. Compound treatment notably reduced serum levels of inflammatory cytokines (IL-6, IL-8, sigA, and TNF-α), indicating an anti-inflammatory effect. Gene expression analysis of mucosal repair markers (PCNA, TGF, and EGFR) confirmed the positive impacts on intestinal recovery processes after treatment. Microbiota analysis revealed concentration-dependent alterations in gut microbial composition, with a notable increase in beneficial bacterial genera such as Muribaculum and Prevotella, suggesting the role of the compound in promoting gut health. Additionally, short-chain fatty acid analysis indicated an increase in beneficial acids, which are critical for the gut and overall health. This investigation highlights the potential therapeutic benefits of Dracocephalum rupestre Hance combining Berberidis Radix in lamb with Salmonella-induced diarrhea.

Normalization of short-chain fatty acid concentration by bacterial count of stool samples improves discrimination between eubiotic and dysbiotic gut microbiota caused by Clostridioides difficile infection.

Short-chain fatty acids (SCFAs) represent a cornerstone of gut health, serving as critical mediators of immune modulation and overall host homeostasis. Patients with dysbiosis caused by Clostridioides difficile infection (CDI) typically exhibit lower SCFAs levels compared to healthy stool donors and, thus, the concentration of SCFAs has been proposed as a proxy marker of a healthy microbiota. However, there is no consistency in the methods used to quantify SCFAs in stool samples and usually, the results are normalized by the weight of the stool samples, which does not address differences in water and fiber content and ignores bacterial counts in the sample (the main component of stool that contributes to the composition of these metabolites in the sample). Here, we show that normalized SCFAs concentrations by the bacterial count improve discrimination between healthy and dysbiotic samples (patients with CDI), particularly when using acetate and propionate levels. After normalization, butyrate is the metabolite that best discriminates eubiotic and dysbiotic samples according to the area under the receiver operating characteristic (ROC) curve (AUC-ROC = 0.860, [95% CI: 0.786-0.934], p < .0001).

Acetate utilization promotes hormone therapy resistance in prostate cancer through neuroendocrine differentiation.

AIMS: Tumor fatty acid (FA) metabolic plasticity plays a pivotal role in resistance to therapy and poses limitations to anticancer strategies. In this study, our aim is to uncover the role of acetate metabolism in neurodifferentiation (NED)-mediated castration-resistant prostate cancer (CRPC). METHODS: We conducted analyses using LC-MS/MS on clinical prostate cancer tissue before and after hormone therapy. We established tumor xenograft mouse models, primary tumor cells, and human-derived organoids to detect the novel mechanism of NED and to identify potential therapies. RESULTS: The hormone therapy-induced upregulation of acetate metabolism was mediated by acyl-CoA synthetase short-chain family member 2 (ACSS2), which increased c-MYC expression for NED induction. Notably, combined treatment with an ACSS2 inhibitor and enzalutamide significantly reduced the xenograft tumor volume. CONCLUSION: Our findings uncovered the critical role of acetate metabolism in NED-mediated CRPC and suggest that ACSS2 inhibitors may represent a novel, low-toxicity strategy when combined with hormone therapy for treating patients with NED-mediated CRPC.