Takumi Tochio

Abstract Background Paraprobiotics, the non-viable microbial cells with health benefits, have gained interest as candidates for preventing food allergies owing to their safety and stability. Heat-killed Lactiplantibacillus plantarum FM8 (FM8) has been reported to induce interleukin (IL)-10 production in dendritic cells in vitro; however, its in vivo efficacy as a standalone intervention remains unexplored. We investigated the preventive effect of heat-killed FM8 in a murine model of ovalbumin (OVA)-induced food allergy. Methods BALB/c mice were assigned to control, OVA-induced allergy, or three FM8 treatment groups receiving FM8 at low (2 × 10⁹ CFU/day), medium (1 × 10¹⁰ CFU/day), or high (5 × 10¹⁰ CFU/day) doses. Food allergy was induced by repeated OVA sensitization and challenge. Allergy symptoms, OVA-specific immunoglobulin E (IgE), and IL-10 levels were measured. Tight junction gene expression, mucin production, gut microbiota composition, and short-chain fatty acids (SCFAs) were also analyzed. Results FM8 supplementation attenuated allergic responses in a dose-dependent manner. Allergy symptom scores were reduced in the High group, and the rectal temperature decline following OVA challenge was ameliorated in both the Med and High groups. The sensitization-induced increase in OVA-specific IgE was also attenuated in these groups. IL-4 expression in Peyer’s patches was reduced, whereas colonic IL-10 expression and serum IL-10 levels were increased in the High group. FM8 supplementation was further associated with increased ileal expression of tight junction-related genes ( Occludin , Claudin-1 and Zo-1 ) and Muc2 , along with a trend toward increased fecal mucin levels; however, no comparable changes in tight junction-related gene expression were observed in the colon. Although taxa with reported SCFA-producing potential were enriched in the High group, cecal acetate and propionate levels remained unchanged, while butyrate levels were decreased. Conclusions FM8 may prevent food allergy by promoting IL-10-associated immunoregulation and enhancing gut barrier-related responses, without a corresponding increase in cecal SCFA concentrations. The contribution of SCFA-related mechanisms remains to be clarified, and further studies are needed to determine clinically feasible dosing and efficacy in humans.

Background: Agaro-oligosaccharides (AOS) have been shown to modulate the gut microbiota in in vitro and animal studies; however, human evidence remains scarce. Methods: Herein, we conducted a four-week open-label, single-arm, non-randomized pilot trial in 18 healthy Japanese adults to examine the association of AOS intake at 200 mg/day with gut microbiota composition and bowel condition. Fecal samples collected before and after the intervention were analyzed using QIIME2-based 16S rRNA sequencing, and bowel condition was assessed with the Bristol Stool Form Scale. This study was registered in the UMIN Clinical Trials Registry (UMIN000056992). Results: AOS intake was not associated with significant changes in bowel condition. Gut microbiota analysis showed no significant alterations in overall community structure but revealed taxon-specific trends in the relative abundance of several bacterial taxa. Notably, nominal changes were observed in the abundance of the Ruminococcus gnavus group and Bacteroides uniformis after the intervention. In addition, quantitative PCR analysis showed an increase in 3,6-anhydro-L-galactose cycloisomerase (ACI) gene abundance after the intervention. Conclusions: These findings suggest that, in this exploratory pilot study, AOS intake was associated with a taxon-specific pattern in the gut microbiota. Further randomized controlled studies are needed to clarify the microbiota-related effects of AOS in humans.

Background & Aims: Age-related variation in the gut microbiota complicates biomarker discovery for pancreatic cancer. This study aimed to identify microbial taxa with minimal age dependence that are associated with pancreatic neoplasia and to develop a practical quantitative PCR (qPCR)-based assay targeting a shared gene involved in butyrate production. Study design: Cross-sectional study. Place and Duration of Study: Department of Gastroenterology and Hepatology, Fujita Health University, Toyoake, Japan, between October 2022 and July 2025. Methodology: Fecal samples from 64 individuals with precursor lesions considered to be at high risk for pancreatic cancer (HR) and 22 patients with pancreatic cancer (PC) were compared with those from healthy controls aged <50 years (Young; n = 71) and ≥50 years (Old; n = 65). Microbiota composition was analyzed by 16S rRNA gene sequencing. A qPCR primer set targeting the but gene, which encodes butyryl-CoA:acetate CoA-transferase, was designed to evaluate the shared genetic potential of the identified minimally age-dependent taxa, namely the Anaerostipes hadrus group and Agathobacter rectalis. Results: The A. hadrus group and A. rectalis showed disease-associated depletion with minimal age dependency. The qPCR assay showed no difference in but gene levels between the Young and Old groups (P = 0.3301). but gene levels in the HR group were comparable to those in the Old group (P > 0.9999), whereas levels in the PC group were significantly lower than those in the Old group (P = 0.0020) and the HR group (P = 0.0136). Conclusion: Targeting the but gene provides a practical approach to assessing the shared butyrate-producing potential of this minimally age-dependent microbial cluster. Within this cross-sectional cohort, but gene levels were preserved in HR individuals, whereas levels in the PC group were reduced, suggesting its potential utility as a non-invasive adjunct for future evaluation in longitudinal monitoring or risk assessment after prospective validation.

Aims: To evaluate the diagnostic potential of previously reported (5ar, nan) and novel microbial gene markers in fecal and salivary microbiomes for the non-invasive detection of colorectal cancer (CRC) progression. Study Design: Cross-sectional study. Place and Duration of Study: Department of Gastroenterology and Hepatology, Fujita Health University, Toyoake, Japan, between June 2024 and July 2025. Methodology: Fecal samples were collected from healthy controls (n = 65) and patients with colorectal adenoma (n = 38) or carcinoma (n = 27). Salivary samples were collected from healthy controls (n = 34) and the same patient cohorts. Microbial gene abundances were quantified via quantitative PCR, and microbiome composition was assessed using 16S rRNA gene sequencing. Group comparisons used the Kruskal-Wallis and Dunn’s tests. Beta diversity differences were evaluated by PERMANOVA. Results: In fecal samples, the abundances of 5ar, nan, and the Fusicatenibacter saccharivorans 16S rRNA gene (fsr) showed a stepwise decline from the adenoma stage onward, with significantly lower levels in carcinoma versus controls (5ar, P = 0.0023; nan, P = 0.0012; fsr, P = 0.0004). Conversely, in saliva, the Fusobacterium periodonticum tyrosine phenol lyase gene (tpl) was significantly reduced only in the carcinoma group (P = 0.0180). Fecal beta diversity differed significantly between controls and both colorectal neoplasia groups (both P ≤ 0.001), whereas salivary beta diversity differed only between controls and carcinoma patients (P = 0.014). Conclusion: Fecal and salivary microbial gene markers may serve as non-invasive, rapid, and cost-effective biomarkers for colorectal neoplasia. Fecal markers captured microbiota disruption at the adenoma stage (representing the early phase of CRC progression), whereas salivary markers predominantly reflected alterations specific to carcinoma (representing the later phase). Integrating these multi-niche biomarkers provides a promising clinical platform for early detection, monitoring of precursor lesions, and postoperative surveillance; however, validation in larger, independent cohorts is warranted.

Background and Aims: Crohn’s disease (CD) is a chronic inflammatory bowel disease characterized by gastrointestinal inflammation, with gut microbiota dysbiosis playing a key role in its onset and progression. This study aimed to evaluate whether 1-kestose supplementation modulates gut microbiota composition and mucin degradation–related biomarkers in patients with clinically inactive to mild CD, and to explore plausible ecological mechanisms in vitro. Study Design: Single-arm pilot intervention study with exploratory laboratory experiments. Place and Duration of Study: Samples were collected at Tokai University Hospital (Japan), and microbiome/qPCR analyses and in vitro assays were performed at Fujita Health University (Japan). The supplementation period was four months. Methodology: Nineteen patients with clinically inactive to mild CD (CDAI ≤ 220) received 1-kestose (3 g) twice daily for 4 months. Fecal microbiota composition was assessed by 16S rRNA gene sequencing, and qPCR quantified nanA homologs (nan levels) as a functional marker related to mucin-degrading potential. Clinical biomarkers (CDAI, fecal calprotectin, CRP, albumin) were monitored. To investigate potential mechanisms, in vitro cultures of Ruminococcus gnavus and Bifidobacterium longum were performed under sugar-supplemented conditions, including 1-kestose, and growth responses were evaluated; short-chain fatty acids (SCFAs) were descriptively assessed in pooled culture supernatants. Results: Clinical biomarkers remained stable throughout supplementation. 1-kestose intake was associated with an increased relative abundance of Bifidobacterium and a decreased abundance of Blautia, along with reduced fecal nan levels. In vitro, B. longum showed enhanced early growth with 1-kestose compared with other sugars, whereas R. gnavus exhibited impaired growth under acidic conditions. Exploratory SCFA measurements suggested higher acetate in sugar-supplemented B. longum cultures. Conclusion: In this single-arm pilot cohort of patients with clinically inactive to mild CD, 1-kestose supplementation was associated with shifts toward potentially beneficial taxa and a reduction in nan levels, a functional marker linked to mucin-degrading potential. These findings, supported by exploratory in vitro observations, suggest that 1-kestose may modulate gut ecological conditions; however, clinical efficacy and causality require confirmation in randomized, placebo-controlled trials with detailed dietary and medication monitoring.