Search Results (10)

Background/Objectives: Gut dysbiosis in children with autism spectrum disorder (ASD) has been associated with alterations in microbial ecology and metabolic function that may contribute to gastrointestinal dysfunction and the severity of clinical manifestations. Synbiotic and probiotic supplementation has emerged as a promising microbiome-targeted strategy for ASD; however, its effects on gut microbiome composition, functional potential, and clinical outcomes remain incompletely understood. We conducted a longitudinal study of Mexican children diagnosed with ASD to analyze changes in the composition, diversity, and functional potential of the gut microbiome during six months of multi-strain synbiotic supplementation. Methods: Stool samples were collected from 25 children with ASD at baseline and after 3 and 6 months of multi-strain synbiotic supplementation. Gut microbiome composition and diversity were analyzed by 16S rRNA gene sequencing, whereas whole metagenome sequencing (WMS) was performed in a subset of samples to evaluate the functional potential of the fecal microbiome. Gastrointestinal symptoms were assessed using the Rome IV criteria, and ASD severity was evaluated with the Childhood Autism Rating Scale (CARS). Results: Twenty-five children with ASD completed the 6 months of synbiotic supplementation. Overall, ASD severity decreased, reflected by a reduction in total CARS score, and improvements in several CARS domains. Gastrointestinal symptoms also decreased significantly. Longitudinal microbiome profiling revealed significant taxonomic and diversity changes over the supplementation period, while WMS identified changes in microbial metabolic potential, including enrichment of tryptophan biosynthesis pathways and reduced L-rhamnose degradation. Conclusions: This exploratory research provides proof-of-concept evidence supporting multi-strain synbiotic supplementation in children with ASD. Larger controlled studies are needed to confirm these findings and clarify their relevance to microbiota–gut–brain axis interactions. The observed concordance between clinical improvements and microbiome remodeling supports further investigation of microbiome-targeted interventions according to ASD severity and duration of supplementation. Full article

Background: Gut microbiome-derived metabolites, particularly short-chain fatty acids (SCFA) and tryptophan derivatives, are central mediators of the gut–brain axis. This ex vivo study assessed how nutritional interventions impact such metabolites during early life, a critical period for neurodevelopment. Methods: The effects of galacto-oligosaccharides (GOS), nutrient blends (vitamins, minerals and amino acids) and their combinations were evaluated in the gut microbiomes of infants (2–4 months, n = 6) and young children (2–3 years old, n = 6) using the ex vivo SIFR^® technology. Results: Baseline microbiome composition was age-dependent, with infants displaying lower α-diversity and greater interpersonal variability. After ex vivo incubation, nutrient blends increased the propionate/butyrate ratio and branched-chain fatty acids in young children and elevated several B-vitamins and amino acid-derived metabolites, including indole-3-carboxaldehyde, imidazoleacetic acid and pipecolinic acid. Combining nutrient blends with GOS exhibited potential synergistic effects on propionate (infants) and 2-hydroxyisocaproic acid (HICA, both age groups). GOS strongly stimulated Bifidobacteriaceae and increased metabolites linked to bifidobacterial metabolism like acetate, HICA, N-acetylated amino acids, aromatic lactic acids and acetylagmatine; in young children, butyrate and γ-aminobutyric acid (GABA) also increased. Conclusions: Combinations of GOS with nutrient blends impacted microbiome-derived metabolites associated with the gut–brain axis, with potential synergistic increases of metabolites with emerging roles in neurodevelopment, including GABA, acetylagmatine and HICA. Despite shared bifidogenic effects, differences between age groups indicate that microbiome maturity may influence responses to nutritional intervention. Future clinical studies are needed to determine whether these metabolite changes translate into neurodevelopmental benefits in vivo. Full article

The gut-brain axis has emerged as a critical pathway influencing central nervous system (CNS) tumor biology through complex microbiome-mediated mechanisms. Understanding these interactions is essential for developing novel therapeutic strategies and biomarkers for CNS tumors. To systematically review and meta-analyze current evidence on gut microbiota interactions with CNS tumors, examining mechanisms, clinical correlations, therapeutic implications, and biomarker potential. We conducted a comprehensive systematic review following PRISMA guidelines, searching PubMed, EMBASE, Google Scholar, and Cochrane Library databases for studies published from 2010–2025. A random-effects meta-analysis of reported statistical outcomes was performed to quantify microbiome alterations using standardized mean differences (Cohen’s d) and diagnostic accuracy measures. Analyses were based on published summary statistics rather than reprocessed raw sequencing data, acknowledging cross-study heterogeneity. From 161 identified records, 12 studies met inclusion criteria (6 clinical studies, n = 387 participants; 6 preclinical studies). Meta-analysis revealed significant Shannon diversity reduction in CNS tumor patients (Cohen’s d = −1.237 [95% CI: −1.614, −0.860; 95% PI: −2.48, −0.12]) with moderate heterogeneity (I² = 60.5%). Evidence demonstrated significant gut microbiome alterations with reduced microbial diversity, increased pathogenic bacteria (Akkermansia muciniphila: 2.23-fold increase, Fusobacterium spp.: 2.04-fold increase), and decreased beneficial bacteria (Bifidobacterium spp.: 47% reduction, Lachnospira spp.: 56% reduction). Diagnostic performance showed fair discrimination (pooled AUC = 0.786 [95% CI: 0.781, 0.791]). Key mechanisms include bidirectional tumor-microbiota interactions through immune system modulation, metabolic pathway alterations involving short-chain fatty acids, and inflammatory response modifications within the altered CNS immune privilege environment. Preliminary evidence suggests gut microbiota alterations in CNS tumor patients, but findings require validation in large, standardized cohorts before clinical application. Current evidence quality is low (GRADE assessment), necessitating substantial additional research. Full article

Guhong injection (GH) is a compound preparation widely utilized in the treatment of cerebrovascular diseases. Accumulating evidence indicates that the gut microbiota is implicated in the development of ischemic stroke (IS). However, although the therapeutic potential of GH in IS may be mediated through the gut microbiota, the intricate relationships among the gut–brain axis, biomarkers, and target proteins remain to be completely explained. A rat model of middle cerebral artery occlusion (MCAO) was utilized to investigate the impact of GH on IS. Our 16S rRNA sequence analysis revealed that GH markedly enhanced the α-diversity of the intestinal microbiome and rectified the imbalance of short-chain fatty acids (SCFAs). Metabolomic analysis indicated that GH reversed 45 biomarkers and 6 disordered metabolic pathways in MCAO rats. Among these, the metabolic pathways of arachidonic acid, α-linolenic acid, fructose, and mannose were closely associated with gut microbiota comprising Lactobacillus modulated by GH. Furthermore, IS-related signaling pathways, including inflammation, autophagy, oxidative stress, and apoptosis, were significantly associated with three gut microbial species influenced by GH. The potential efficacy of GH in the context of IS is mediated through multiple pathways, involving the gut microbiota, SCFAs, biomarkers, and target proteins. This process partly relies on the gut–brain axis. Full article

Recent studies suggest that the dietary intake of human milk oligosaccharides (HMOs) provides health benefits from infancy up to adulthood. Thus far, beneficial changes in the adult gut microbiome have been observed at oral doses of 5–20 g/day of HMOs. Efficacy of lower doses has rarely been tested. We assessed four HMO molecular species—2′Fucosyllactose (2′FL), Lacto-N-neotetraose (LNnT), 3′Sialyllactose (3′SL), and 6′Sialyllactose (6′SL)—at predicted doses from 0.3 to 5 g/day for 6-year-old children and adults (n = 6 each), using ex vivo SIFR^® technology (Cryptobiotix, Ghent, Belgium). This technology employing bioreactor fermentation on fecal samples enables us to investigate microbial fermentation products that are intractable in vivo given their rapid absorption/consumption in the human gut. We found that HMOs significantly increased short-chain fatty acids (SCFAs), acetate, propionate (in children/adults), and butyrate (in adults) from predicted doses of 0.3–0.5 g/day onwards, with stronger effects as dosing increased. The fermentation of 6′SL had the greatest effect on propionate, LNnT most strongly increased butyrate, and 2′FL and 3′SL most strongly increased acetate. An untargeted metabolomic analysis revealed that HMOs enhanced immune-related metabolites beyond SCFAs, such as aromatic lactic acids (indole-3-lactic acid/3-phenyllactic acid) and 2-hydroxyisocaproic acid, as well as gut–brain-axis-related metabolites (γ-aminobutyric acid/3-hydroxybutyric acid/acetylcholine) and vitamins. The effects of low doses of HMOs potentially originate from the highly specific stimulation of keystone species belonging to, for example, the Bifidobacteriaceae family, which had already significantly increased at doses of only 0.5 g/day LNnT (adults) and 1 g/day 2′FL (children/adults). Full article

Indole acetic acid (IAA), an intestinal bacteria-derived tryptophan metabolite, has been detected at abnormal concentrations in the cerebrospinal fluid and urine of depressed individuals. The effects of such altered IAA concentrations on mood regulation are not known. A mouse model of unpredictable chronic mild stress (UCMS) was used to assess the effects of IAA administration (50 mg/kg). Treatment with IAA for 5 weeks attenuated depression and anxiety-like behaviours, improved hypothalamus–pituitary–adrenal axis dysfunction and increased brain-derived neurotrophic factor expression. IAA supplementation also enhanced the serotonin pathway in the brain and gut. UCMS caused an imbalance of microbial indole metabolites in the colon, whereas IAA treatment reversed this. However, IAA intake did not affect the concentrations of indoles in the brain. Intestinal bacteria in different sections of the gut were altered by IAA treatment, with the colon showing more changes than other segments. The gut microbiome in the colon had increased proportions of Ruminococcaceae UCG013, Ruminiclostridium 6, Prevotella, Alloprevotella and Bacteroides species, which can produce short-chain fatty acids and indole derivatives. Cumulatively, our study highlights the potential of IAA treatment to alleviate mood disorders and offers a theoretical basis for understanding the antidepressant effects of IAA. Full article

In the past few decades, obesity has reached pandemic proportions. Obesity is among the main risk factors for cardiovascular diseases, since chronic fat accumulation leads to dysfunction in vascular endothelium and to a precocious arterial stiffness. So far, not all the mechanisms linking adipose tissue and vascular reactivity have been explained. Recently, novel findings reported interesting pathological link between endothelial dysfunction with gut hormones and gut microbiota and energy homeostasis. These findings suggest an active role of gut secretome in regulating the mediators of vascular function, such as nitric oxide (NO) and endothelin-1 (ET-1) that need to be further investigated. Moreover, a central role of brain has been suggested as a main player in the regulation of the different factors and hormones beyond these complex mechanisms. The aim of the present review is to discuss the state of the art in this field, by focusing on the processes leading to endothelial dysfunction mediated by obesity and metabolic diseases, such as insulin resistance. The role of perivascular adipose tissue (PVAT), gut hormones, gut microbiota dysbiosis, and the CNS function in controlling satiety have been considered. Further understanding the crosstalk between these complex mechanisms will allow us to better design novel strategies for the prevention of obesity and its complications. Full article

Background: Bariatric surgery is proven to change eating behavior and cause sustained weight loss, yet the exact mechanisms underlying these changes are not clearly understood. We explore this in a novel way by examining how bariatric surgery affects the brain–gut–microbiome (BGM) axis. Methods: Patient demographics, serum, stool, eating behavior questionnaires, and brain magnetic resonance imaging (MRI) were collected before and 6 months after laparoscopic sleeve gastrectomy (LSG). Differences in eating behavior and brain morphology and resting-state functional connectivity in core reward regions were correlated with serum metabolite and 16S microbiome data. Results: LSG resulted in significant weight loss and improvement in maladaptive eating behaviors as measured by the Yale Food Addiction Scale (YFAS). Brain imaging showed a significant increase in brain volume of the putamen (p.adj < 0.05) and amygdala (p.adj < 0.05) after surgery. Resting-state connectivity between the precuneus and the putamen was significantly reduced after LSG (p.adj = 0.046). This change was associated with YFAS symptom count. Bacteroides, Ruminococcus, and Holdemanella were associated with reduced connectivity between these areas. Metabolomic profiles showed a positive correlation between this brain connection and a phosphatidylcholine metabolite. Conclusion: Bariatric surgery modulates brain networks that affect eating behavior, potentially through effects on the gut microbiota and its metabolites. Full article

Background: Irritable bowel syndrome (IBS) is a functional disorder without any pathological alteration, in which the alterations of the Candida/Saccharomyces ratio of the gut microbiota, the balance of pro and anti-inflammatory cytokines and the brain-gut-microbiome axis are important for the development and progression of IBS. The aim of the study was to identify natural products, including essential oils or hydrolates, which were contextually harmless for the gut beneficial strains (e.g., Saccharomyces spp.) but inhibitory for the pathogenic ones (Candida spp.). Methods: The effectiveness of 6 essential oils and 2 hydrolates was evaluated using microbiological tests, carried out on 50 clinical isolates (Candida, Saccharomyces and Galattomyces species) and 9 probiotic strains (Saccharomyces cerevisiae, Lactobacillus species, Akkermansia muciniphila and Faecalibacterium prausnitzii) and immunological and antioxidant assays. Results: The study led to a mixture based on a 1/100 ratio of Citrus aurantium var. amara essential oil / Vitis vinifera cv Italia hydrolate able to contextually reduce, in a concentration-dependent manner, the ability of Candida species to form hyphal filaments and have an interesting immunomodulatory and anti-oxidant action. This mixture can potentially be useful in the IBS treatment promoting the restoration of the intestinal microbial and immunological balance. Full article

Rationale: There is a worldwide prevalence of generalized anxiety and major depressive disorders (MDD). Gut–brain axis dysfunction, antibacterial activity, and modulatory effects of antidepressants toward intestinal bacteria have been shown both in vitro and in vivo. Objectives: In this study, we aimed to investigate the effects of hospital stay, including escitalopram administration, on gut microbiota in patients with depressive episodes. Methods: After admission to the hospital and 7-days washout from all medications the composition of fecal microbiota samples was evaluated at baseline (W0) and after 6 weeks (W6), using 16S rRNA sequencing. The study was conducted on 17 inpatients (52.9% females), who followed the same daily hospital routine, including a standard diet and received 5–20 mg daily doses of escitalopram. Results: At the end of treatment (W6), no change was observed in the Chao1 index. However, Shannon (median (Q1–Q3): W0 2.78 (2.67–3.02) vs. W6 3.11 (2.80–3.30)), and inverse Simpson (median (Q1–Q3): W0 9.26 (7.26–13.76) vs. W6 12.13 (9.17–15.73)) indices increased significantly compared to baseline values (False Discovery Rate p (q) = 0.031 and q = 0.011, respectively). We also found that between-subject W0 Bray–Curtis dissimilarities were significantly higher than W0–W6 within-subject dissimilarities (median (Q1–Q3): 0.68 (0.56–0.77) vs. 0.38 (0.35–0.52), two sided Mann–Whitney test p < 0.00001. The within-subject dissimilarities did not depend on sex, age, BMI, illness duration and a daily dose of escitalopram. No significant differences between taxa levels, at the studied time points, were observed when adjusted for multiple hypotheses testing procedures. Conclusions: We conclude that a six-week treatment in a psychiatric hospital setting resulted in increased alpha biodiversity in fecal microbiota, however its causal relationship with patients’ mental health was not proved. We have also found that individual microbiome stability was not affected by hospitalization. Full article