Abstract Maternal obesity (MO) is a growing global concern linked to long-term disease risk in offspring and may also increase prostate cancer susceptibility, although the mechanisms remain unclear. We tested whether MO-induced gut dysbiosis promotes prostate cancer in male offspring and reprograms immune function. Using a TRAMP-C1 allograft model, we evaluated male offspring from dams fed a control diet or an obesity-inducing diet (OID). Gut microbiota was assessed by 16S rRNA sequencing and SCFA profiling. Causality was tested using antibiotic ablation and fecal microbiota transplantation (FMT), and microbiota modulation was further examined using a prebiotic intervention with partially hydrolyzed guar gum (PHGG). Activated splenic T cells were analyzed with paired RNA-seq and ATAC-seq. MO increased prostate tumor burden in adult offspring and induced gut dysbiosis marked by reduced α-diversity and significantly lower fecal butyric acid. Gut microbiota ablation reversed the MO-induced increase in tumor growth, whereas FMT from MO offspring transferred the pro-tumor phenotype to control mice. MO induced profound immune reprogramming that was specific to CD4+ T cells and not observed in CD8+ T cells. RNA-seq data revealed activation of Th2 and pro-inflammatory pathways, including Th17 differentiation (NES 1.96, p.adj 0.009) and JAK-STAT signaling (NES 2.1, p.adj 0.0009). We also observed reduced antigen-presentation (NES -2.24, p.adj 0.0007) and interferon-signaling programs (NES -3.4, p.adj 8.39E-06), indicating impaired IFN-driven activation.Twenty-one loci exhibited concordant chromatin (ATACseq) and transcriptional remodeling, including repression of Zbtb10 and Ifrd1, regulators of Th1 differentiation. These molecular changes manifested in vivo as increased Th2 (GATA3+) and Th17 (RORγ+) cells and reduced Th1 (Tbet+) cells in spleen, and impaired CD8+IFNγ+ cytotoxicity in tumors. Antibiotic ablation partially normalized inflammatory signatures, indicating that gut dysbiosis contributes to—but does not fully explain—MO-driven immune remodeling. These findings suggest a combined effect of long-lasting epigenetic alterations and microbiome-driven signals. Prebiotic PHGG, which increases SCFA production, reduced tumor growth in MO offspring, demonstrating that microbiome-targeted interventions can mitigate MO-induced cancer susceptibility. Overall, our data indicates that MO is associated with a microbiota-dependent increase in prostate cancer risk in offspring, alongside a durable and epigenetically imprinted CD4+ T-cell program. Citation Format: Fabia de Oliveira Andrade, Lu Jin, Melike Özgül Önal, Seema Yadav, Sercan Kenanoglu, Christopher Staley, Leena Hilakivi-Clarke. Maternal obesity promotes gut dysbiosis, CD4+ T-cell reprogramming and increased prostate cancer in offspring [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 2869.

The vaginal microbiome plays a complex role in tenofovir's mucosal pharmacology. While the relative contribution of systemic versus local concentrations to PrEP PK/PD is an ongoing debate, the development of effective HIV prevention requires an understanding of events at the site of transmission. Our objective was to further understand the relationship between tenofovir mucosal pharmacology and non-optimal vaginal microbiota using the ex vivo vaginal tissue model. Vaginal and cervical explants were produced from cadaver tissue using a biopsy punch. Explants were incubated with Prevotella bivia (103-105 colony forming units/ml) with and without tenofovir for 24 h. TFVdp and endogenous adenosine triphosphate (dATP) were quantified using liquid chromatography tandem mass spectroscopy. Explants were then challenged with 106 TCID50 the viral concentration where 50% of tissue cultures are infected, of HIVJR-CSF for 3 h. Explants were cultured on gel-foam rafts for 48 h then collected for HIV RNA quantification using RT-qPCR. TFVdp formation in vaginal tissue was approximately 76% lower in anaerobic conditions (p = 0.2) compared to aerobic. While dATP concentrations did not significantly differ between any Prevotella bivia concentrations and the Prevotella-free control, TFVdp and TFVdp:dATP ratio in vaginal tissue decreased as Prevotella bivia concentrations increased, although not statistically. Unexpectedly, tenofovir efficacy increased as Prevotella bivia concentrations increased. The ex vivo tissue model was successful in demonstrating the pharmacology of TFVdp is affected by Prevotella bivia. Viral replication was also affected by Prevotella bivia; therefore, further work is needed to fully understand effects on tenofovir pharmacodynamics.

Mycophenolic acid (MPA) has complex pharmacokinetics in part due to enterohepatic recirculation (EHR). A deeper understanding of MPA pharmacokinetics and specifically how EHR and patterns of EHR affect exposure will improve immunosuppression outcomes. This study provides a contemporary and comprehensive assessment of MPA and metabolites in the blood and urine with a focus on EHR characteristics. Kidney transplant recipients (n = 84) receiving mycophenolate mofetil (MMF) and tacrolimus underwent an intensive MPA pharmacokinetic assessment. Pharmacokinetics of MPA and its metabolites, EHR

SUMMARYColorectal cancer (CRC) is a significant global health concern that is growing in prevalence, especially in younger populations. The gut microbiome is an increasingly recognized factor in the development and progression of numerous diseases, including CRC. This review explores the current research on the causal relationship between the microbiome and CRC, including the strengths and limitations of the current models for studying this complex interaction. We then delve into key microbial metabolites and their effects on host signaling pathways in the context of CRC and highlight specific bacterial species with direct links to CRC development and progression. Existing microbiota-targeted therapies such as pre- and pro-biotics and fecal microbiota transplantation are described, as well as innovative microbiome-focused strategies that are currently in development, like quorum quenching. Finally, we address the major challenges in the field, such as conflicting research findings and the need for a systems-level, multi-omic approach to describe the intertwined and bidirectional host-microbe interactions.

Pitt-Hopkins syndrome (PTHS) is an ultrarare neurodevelopmental disorder caused by TCF4 gene mutations and frequently accompanied by severe gastrointestinal (GI) dysfunction, suggesting disruption of the gut-brain axis. We conducted a randomized, double-blind, placebo-controlled trial with open-label extension to evaluate microbiota transplant therapy (MTT) in seven children with PTHS. MTT, comprised of antibiotic pretreatment, bowel cleansing, and 12 weeks of oral encapsulated donor microbiota, was safe and well tolerated. Compared with placebo, MTT produced substantial (large effect size), durable improvements in GI symptoms and modest behavioral benefits persisting up to three-six months. Treatment resulted in 25–28% donor engraftment, increased Bifidobacterium bifidum , decreased Enterocloster bolteae , and significantly elevated fecal butyrate. Buccal mitochondrial Complex IV activity, reduced at baseline relative to typically developing controls, improved following treatment. These findings provide preliminary evidence that MTT can remodel the gut microbiome, influence metabolic and mitochondrial pathways, and improve clinical outcomes in a monogenic neurodevelopmental disorder. This trial is registered under at ClinicalTrials.gov (NCT04132427).

The intestinal microbiota plays a critical role in post-surgical wound healing following bowel resection; however, perioperative, prophylactic antibiotic administration may deleteriously affect it. We previously used 16S rRNA amplicon sequencing of stool samples to assess perioperative and longitudinal changes in the microbiome through 6 months in patients undergoing (i) colonoscopy after mechanical bowel prep (MBP) alone, (ii) non-resectional colorectal surgery after MBP with oral antibiotics and prophylactic intravenous antibiotics no longer than 24 h post-operative (surgical bowel prep [SBP]), and (iii) resectional colorectal surgery with SBP. Our objective in this study was to investigate the translational utility of SparCC co-occurrence networking to uncover biologically relevant patterns. Network topological parameters and hub species were calculated using NetCoMi, and permutational statistical tests were used to compare parameters. Network similarity among cohorts and time points generally matched changes in beta diversity, except in the resectional cohort, where all networks could not be differentiated statistically. Similarity in centrality measures among hub species was frequently significantly less similar than expected by chance and corresponded to an increased edge density and modularity, suggesting the latter parameters may reflect re-stabilization of the microbiome following surgery. We further noted the infrequently reported genera Enterocloster and Ruthenibacter were hub species during time points associated with surgical recovery, suggesting potentially novel roles for these genera in wound healing. Streptococcus, frequently implicated in surgical site infections at our center, was also frequently positively associated with Blautia throughout all networks, suggesting an increasing abundance of commensal bacteria serves as a prophylactic strategy.IMPORTANCEThis study employs the emerging approach of co-occurrence networking to assess ecological dynamics in the microbiome following colonoscopy and colorectal surgery. We expand upon applications of this approach to determine hub species and investigate clinically translational interpretations of network topological parameters in the context of recovery across three different trajectories of perturbation. Our results provide a context in which to interpret these network parameters biologically and represent a foundational step in beginning to quantitatively leverage network-based approaches to study microbial ecology. Furthermore, we identify network hub taxa that may play previously unexplored roles in wound healing.

Tacrolimus (TAC) is known for its high pharmacokinetic variability which cannot be fully explained by pharmacogenomic (PGx) and clinical variables. We identified gut microbiome associated with TAC pharmacokinetic variability in allogeneic hematopoietic cell transplant (HCT) recipients. In this observational study, metagenomic shotgun sequencing was used to analyze stool microbiome collected within ± 10 days from time of first oral TAC trough at steady state. TAC steady state concentrations (222 IV continuous infusion and 436 oral troughs) were modeled to estimate TAC clearance (CL) and oral bioavailability (F) using nonlinear mixed effects modeling. The effect of clinical covariates, PGx variants and concomitant medications on CL and F were evaluated. Machine learning was used to identify bacterial species associated with variability in F and CL. The identified species were incorporated into the final model, and simulations were conducted to estimate their clinical relevance on oral TAC troughs. TAC population CL was 6.91 L/h and population F was 64.4

Background Increasing evidence suggests that dysbiosis of the gut microbiome plays a significant role in the onset and pathogenesis of inflammatory bowel disease (IBD). Many of the pathogenic functions of these gut bacteria involve community-wide coordination using various autoinducer molecules and associated receptors, collectively known as quorum sensing (QS) systems. Disruption of these QS systems, a process known as quorum quenching (QQ), has shown promise in sharply inhibiting these pathogenic functions and has become a target of interest in microbiota-focused therapies. Here, we utilize SsoPox, a QQ enzyme that degrades long-chain acyl-homoserine lactones (AHLs), an autoinducer-1 QS signal, to examine the role QS plays in dextran-sulfate sodium (DSS)-induced colitis. Results Mice were given water supplemented with SsoPox at either 1mg/mL or 2mg/mL for 6 weeks, with DSS supplementation during the latter 3 weeks. We found that male and female mice administered SsoPox at 2mg/ml had longer colons compared to their respective drinking water controls (ANOVA F = 10.218, 3.663, P = 0.005, 0.072, respectively) while also exhibiting greater fecal concentrations of IgA (ANOVA F = 10.403, 4.374, P = 0.005, 0.052, respectively). SsoPox treatment was also observed to significantly increase the total transcript abundances of lactic acid-producing bacteria, including members of the families Bifidobacteriaceae and Lactobacillaceae (Kruskal-Wallis K = 6.361, 5.763, P = 0.012, 0.016, respectively). Conclusions These data suggest that SsoPox may cause community-level changes that promote activity of lactic-acid-producing taxa and potentially increase lactic acid production, representing a possible mechanism for the anti-inflammatory and anti-pathogenic effects of SsoPox supplementation reported here.

Breast cancer risk and mortality are associated with disrupted gut microbiome functions which in turn can affect tumor immune responses. One source of disruption could be stress. Social isolation (SI) stress consistently increases breast cancer risk and mortality in preclinical models and women, but whether SI promotes mammary tumor growth by affecting gut microbiome has not been studied. We investigated if increased E0771 mammary tumorigenesis in SI female C57BL/6 mice was associated with changes in their gut microbiome by treating mice with an antibiotic mix that suppresses bacterial abundance and by performing fecal microbiota transplantation (FMT) from SI or group-housed (GH) donors to GH host. The effect of SI on anti-tumor CD8 + T and immunosuppressive Foxp3 + Treg cells was also studied. Fecal bacteria that were present at different abundances between GH and SI mice were short chain fatty acid (SCFA) producers, and the most consistent change across three replicate studies was decreased fecal abundance of Akkermansia genus in SI mice. In addition, fecal propionic acid levels were reduced in SI mice, compared with GH mice, in agreement with Akkermansia being propionic acid producer. SI reduced the activation of CD8 + T cells systemically and in the tumor microenvironment, while the levels and activation of immunosuppressive Foxp3 Tregs were increased. Antibiotic treatment reversed increased mammary tumorigenesis and immunosuppression in SI mice but did not affect GH mice. Further, FMT from SI donors increased tumor growth in GH host, compared with FMT from GH donor. Gut dysbiosis caused by SI may be driving their increased mammary tumorigenesis, potentially through gut dysbiosis induced immunosuppression.

Background: Inflammatory bowel disease (IBD) biomarkers demonstrate substantial inter-individual variability, with 20% of patients showing no elevation despite active disease. Multi-omics integration offers promise for molecular stratification, but existing approaches suffer from modality dominance and high false discovery rates. Methods: We applied block-scaled early fusion principal component analysis to the Integrative Human Microbiome Project dataset, integrating serologic data with metagenomics-derived microbial taxonomic profiles and metagenomics-derived functional enzymatic capacity from 7 controls and 11 IBD cases at temporally matched timepoints. Three network inference strategies (cosine similarity, k-nearest neighbor Louvain, and shared-signal correlation) were used to identify cross-modal bridge features. Results: Block scaling prevented taxonomic modality dominance despite 135 taxa versus 8–11 serologic features. Canonical IBD serology markers (ASCA, ANCA, OmpC, CBir1) emerged as stable immune anchors across health and disease, but microbial partners diverged by disease status. In controls, ASCA bridged to Flavonifractor and oxidative phosphorylation enzymes; whereas in IBD cases, to Peptoniphilus and peptidoglycan biosynthesis (MurB). Serologic features dominated the leading principal component in both groups (77.4% controls, 71.0% cases), while microbial/enzymatic features contributed more to case heterogeneity. Cross-method bridge agreement ranged 0.689–0.893 for nodes spanning ≥2 modalities. Conclusions: This framework mitigates modality dominance and identifies reproducible cross-modal bridges linking microbiome composition, metabolic activity, and immune state to disease status. Temporal matching was used to reduce potential bias arising from asynchronous host and microbial measurements in a biologically dynamic system. This approach provides a hypothesis-generating framework for multimodal biomarker discovery in IBD and warrants validation in larger, prospectively collected cohorts.

Background:Lewy body disease (LBD) is a progressive neurodegenerative a-synucleinopathy, whereas isolated REM sleep behavior disorder (iRBD) is recognized as a prodromal stage of LBD. Although growing evidence implicates the gut-brain axis in neurodegeneration, the taxonomic and functional roles of the gut microbiome across the prodromal-to-symptomatic LBD continuum remain poorly defined. Methods:Here, we performed shotgun metagenomic sequencing on stool samples from 25 patients with LBD (10 mild cognitive impairment due to LBD [MCI-LB] and 15 dementia with Lewy bodies [DLB]), 10 individuals with iRBD, and their household matched cohabitant controls to characterize disease-associated microbial alterations while minimizing environmental confounding. Results:Despite no significant differences in global microbial diversity, we identified convergent shifts in microbial taxa, metabolic pathways, and gene families across disease stages. Both LBD and iRBD showed increased abundance of microbial taxa potentially associated with gut barrier disruption, as well as higher abundance of functional pathways related to lipopolysaccharide biosynthesis. LBD showed lower abundance of pathways related to complex carbohydrate fermentation, and both groups showed lower abundance of pathways associated with neurotransmitter-related metabolism. In particular, pathways and gene families associated with starch degradation were reduced in LBD, and those associated with histidine-to-glutamate/ GABA metabolism were reduced in both groups. Discussion:These exploratory findings represent the first high-resolution, shotgun metagenomic characterization of gut microbiome alterations across the LBD continuum, highlighting functional patterns that may serve as candidate markers of disease progression in future longitudinal and mechanistic studies.

Background Microbiota disruption following colorectal surgery contributes to impaired gastrointestinal recovery and postoperative inflammation. Perioperative interventions essential for surgical safety, including mechanical bowel preparation and antibiotic prophylaxis, profoundly suppress microbial community diversity and fermentative metabolic activity, creating a window of ecological vulnerability during the early postoperative period. Despite growing recognition of the microbiome’s role in postoperative physiology, including its contributions to epithelial repair, immune regulation, and gastrointestinal motility, no standardized strategies exist to restore gut microbial composition and function after surgery. Here, we evaluated the safety, feasibility, and exploratory biological effects of early postoperative microbiota transplant therapy (MTT) following colorectal surgery. Results In this phase I clinical study, twelve patients undergoing sigmoid colectomy for diverticular disease or colon cancer received MTT via nasojejunal feeding tube on postoperative day 2 and were compared with matched non-MTT patients from a prior cohort undergoing identical surgery. Longitudinal microbiome, metabolomic, and immune profiling identified sustained donor-attributed microbial community similarity at 16S resolution and recovery-associated increases in fecal short-chain and branched-chain fatty acids by postoperative day 14, consistent with restoration of microbial metabolic activity. Exploratory integrated microbiome-metabolite modeling identified a dominant recovery-associated latent axis reflecting shared variation between microbial community structure and metabolite profiles across the postoperative period. Longitudinal immune profiling within MTT recipients demonstrated temporally structured immune remodeling characterized by early innate immune shifts followed by later adaptive immune transitions consistent with immune resolution. Cross-omic integration revealed time-stratified associations linking microbial and metabolic recovery trajectories with staged immune remodeling. No adverse events were attributed to MTT. Conclusions Early postoperative MTT was feasible, well tolerated, and associated with exploratory microbial, metabolic, and within-recipient immune recovery dynamics following colorectal surgery. Together, these findings suggest that postoperative recovery may involve temporally aligned microbial, metabolic, and immune dynamics, and that MTT may serve as a useful biological perturbation model for investigating host-microbiome interactions during surgical recovery. Prospective controlled studies are needed to determine whether these observations are MTT-specific and whether microbiome restoration strategies can improve clinical outcomes such as reduced ileus, surgical site infection, or anastomotic complications.

The human gut microbiome is a highly dynamic and exceptionally diverse microbial ecosystem. Gut dysbiosis, or an imbalance in gut microbiota, can lead to various metabolic conditions associated with immune activation and systemic inflammation. Gaucher disease (GD) is a rare lysosomal disorder caused by variations in the GBA1 (Glucosylceramidase Beta 1) gene, leading to the accumulation of glucocerebrosides in lysosomes, predominantly in macrophages. This leads to multi-organ complications in patients, such as hepatosplenomegaly, hematological and skeletal abnormalities. GBA1 variants also predispose individuals to neurodegenerative disorders such as Parkinson's disease (PD). Emerging preclinical evidence suggests that gut dysbiosis may contribute to the pathophysiology of GD and related complications, although causal relationships have not been established. Recent studies have reported gut microbial alterations in preclinical models harboring GBA1 variants, descriptively linking dysbiosis with chronic immune activation and PD-related phenotypes. Additional research is warranted to define the role of gut dysbiosis in the pathogenesis of GD and to explore potential adjunctive strategies in a hypothesis-generating context. This review summarizes current evidence regarding gut dysbiosis in GD and discusses its conceptual relevance to immunological, metabolic, neurological, and skeletal manifestations in a hypothesis-generating framework. Probiotics, prebiotics, synbiotics, dietary supplements, and lifestyle modifications are discussed as exploratory adjunctive approaches that warrant further investigation in parallel with established GD therapies.

ABSTRACT Streptococcus gordonii is a gram-positive oral bacterium capable of adhering to a variety of biotic and abiotic surfaces and forming biofilms. To characterize physiological changes associated with biofilm formation in S. gordonii , we investigated the roles of two putative GCN5-related N-acetyltransferases (GNATs), SGO_2030 and SGO_2031, in in vitro biofilm formation on saliva-coated surfaces using the laboratory strain DL1. Our results demonstrate that SGO_2031, but not SGO_2030, seems to contribute to biofilm formation by modulating the abundance of extracellular polysaccharides within the biofilm matrix. This defect in biofilm formation observed by the deletion of SGO_2031 resulted in a significant fitness disadvantage during colonization of the murine oral cavity compared to the wild-type parent strain. Consistent with the role of S. gordonii as an early colonizer of tooth surfaces that influences oral biofilm community structure, inoculation with either the wild-type or the SGO_2031 mutant strain led to distinct alterations in the murine oral microbiome composition. Deletion of SGO_2031 also resulted in changes in protein acetylation patterns, as assessed by Western immunoblot analysis, supporting the role of this enzyme as an acetyltransferase. Given that SGO_2031 is conserved and widely distributed among streptococci, we propose naming this enzyme Streptococcal Lysine Acetyltransferase A (SktA). IMPORTANCE Protein acetylation is a common posttranslational modification conserved across all domains of life. In bacteria, protein acetylation is carried out by homologs of the GCN5-related N-acetyltransferase (GNAT) family. GNATs catalyze the transfer of an acetyl group from acetyl-CoA to the ε-amino group of lysine residues on proteins. This process changes the charge and length of lysine residues, resulting in changes to protein function. Streptococcus gordonii is predicted to encode 17 GNAT homologs. Here, we report that one of them, SGO_2031 (SktA), plays an important role in S. gordonii biofilms.

BackgroundFermentable dietary fibers, or microbiota-accessible carbohydrates (MACs), are hypothesized to enhance responsiveness to immune checkpoint blockade (ICB) therapy in breast cancer (BC) by increasing fecal short-chain fatty acid (SCFA) production. However, existing research findings have been inconsistent. Given that hormone-sensitive breast cancer is highly influenced by estrogen levels, the presence of estrogenic isoflavones in certain MAC sources may partially account for these discrepancies. Consequently, investigating the roles of isoflavones versus MACs in BC models is warranted.MethodsC57BL/6Tac mice were fed low-MAC (AIN93G), low-MAC supplemented with isoflavone genistein, high-MAC (5V5M), or high-MAC isoflavone (high-MACi; 5058D) diet to assess anti-PD1 efficacy against E0771 triple-negative breast cancer (TNBC) and 7,12-dimethylbenz[a]anthracene (DMBA)-initiated estrogen receptor α-positive (ERα+) mammary tumors. Effects of blocking ERα with tamoxifen (TAM) and dietary impact on the gut microbiome and immune signaling (NanoString) were also evaluated.ResultsHigh-MAC diets increased fecal microbial diversity, the abundances of SCFA-producing families, and fecal SCFA levels, compared with the low-MAC diet. Anti-PD1 was effective in TNBC models with high-MAC or low-MAC diets, but responsiveness was eliminated by the inclusion of isoflavones (high MACi) or genistein (low MAC). Anti-PD1 reduced exhausted CD8+ T cells in high-MAC-fed mice but increased them in high-MACi-fed mice. ERα+ tumors were resistant to anti-PD1. TAM induced sensitivity to anti-PD1 in both TNBC and ERα+ models possibly by modulating TH17 pathways.ConclusionsOur results highlight the role of diet in impacting the effectiveness of ICB therapies. Increased SCFA alone is not predictive of response to anti-PD1, but if the tumor expresses ERα or if the diet contains ERα-activating compounds, such as isoflavones, blocking ERα+ might convert unresponsive tumors responsive to anti-PD1.

INTRODUCTION:To analyze microbial reduction and diversity changes after cleaning and shaping procedures, and calcium hydroxide interappointment medication. The influence of clinical and radiographic factors was assessed as well. METHODS:Thirty-two teeth diagnosed with pulp necrosis and evidence of apical periodontitis were included. Five samples were collected on each tooth: surface sample before access (C1), before treatment (S1), after cleaning and shaping with ultrasonic irrigant activation (S2), at the second visit before removal of the temporary restoration (C2), and after removal of calcium hydroxide (S3). All samples were processed using quantitative real-time polymerase chain reaction (qPCR) and 16S rRNA next-generation sequencing. The Shannon and Chao1 indices were used to measure alpha diversity. Differences in abundances of genera were evaluated using the Kruskal-Wallis test. Differences in community composition (beta diversity) were evaluated using analysis of similarity (ANOSIM) with Bray-Curtis dissimilarity matrices. RESULTS:The qPCR analysis revealed significant differences between S1 and S2 as well as between S1 and S3 (P = .0001). No significant differences between S2 and S3 were observed for qPCR (P = .400) as well as for Chao1 alpha diversity. ANOSIM revealed differences between S1 and S3 (P < .001, R = 0.59), and between S1 and S2 (P < .001, R = 0.40). Microbial composition differed according to percussion sensitivity (ANOSIM R = 0.07, P = .023) and sinus tract presence (ANOSIM R = 0.06, P = .03), although the effect sizes were small. Most of preoperative taxa (top 20) found before treatment were significantly impacted by root canal procedures except Peptostreptococcus and Clostridiales (P > .05). The relative abundance of Schaalia (P = .004) and Enterococcus (P = .001) increased significantly after treatment. CONCLUSION:A significant reduction in microbial load after instrumentation (S2) and after calcium hydroxide medication (S3) was observed. The effect on root canal composition (beta diversity) was impacted after the cleaning and shaping. No additional changes in qPCR and beta diversity were observed after the use of calcium hydroxide. The effects produced by clinical factors although significant were low, and the results reinforce the value of robust chemical and mechanical disinfection procedures.

X-linked adrenoleukodystrophy (ALD) is a severe neurometabolic disorder caused by mutations in the ABCD1 gene, leading to impaired peroxisomal β-oxidation of very long-chain fatty acids (VLCFAs). The accumulation of saturated VLCFAs, predominantly C26:0, in plasma and across all tissues, contributes to adrenal dysfunction and progressive neurodegeneration. No approved therapy addresses the diverse spectrum of ALD manifestations, underscoring the urgent need for safe, accessible, and preventive treatments. Nervonic acid (NA), a monounsaturated fatty acid, is potentially beneficial for ALD through its neuroprotective effects. Here, we report the safety and therapeutic efficacy of NA in a 4-week dietary intervention study using a mouse model of ALD. NA treatment significantly decreased plasma C26:0-lysophosphatidylcholine, a diagnostic and disease-severity biomarker of ALD, by about 60% as early as one week after intervention. After 4-week treatment, NA markedly reduced free C26:0 and total saturated VLCFA levels in plasma and tissues. Moreover, we observed approximately 56% reduction in brain C26:0-lysophosphatidylcholine levels in NA-fed mice, an effect not reported with other drug intervention. Through comparative microbiome analysis, we show for the first time distinct baseline differences between ALD and wild-type mice, with dietary fatty acid supplementation preventing further dysbiosis. No adverse effects on body weight or food intake were observed throughout the study. Overall, this is the first report demonstrating that an oral dietary fatty acid can ameliorate the hallmark biochemical abnormalities of ALD in plasma and brain, highlighting its potential as a safe and effective therapy, particularly for presymptomatic individuals carrying this genetic defect.