The gut microbiota is believed to be a critical factor in the pathogenesis of IBS, and its metabolic byproducts, such as short-chain fatty acids (SCFAs), are known to influence gut function and host health. Despite this, the precise role of SCFAs in IBS remains a topic of debate. In this study, we examined the bacterial community structure by 16S rRNA gene profiling and SCFA levels by UPLC-MS/MS in fecal samples from healthy controls (HC; n = 100) and non-constipated patients (IBS-D and IBS-M; NC-IBS; n = 240) enrolled in 19 hospitals in Italy. Our findings suggest a significant difference between the fecal microbiomes of NC-IBS patients and HC subjects, with HC exhibiting higher intra-sample biodiversity. Furthermore, we were able to classify non-constipated patients into two distinct subgroups based on their fecal SCFA levels (fecal catabotype "high" and "low"), each characterized by unique taxonomic bacterial signatures. Our results suggest that the fecal catabotype with higher SCFA levels may represent a distinct clinical phenotype of IBS that could have implications for its diagnosis and treatment. This study provides a new perspective on the intricate relationship between the gut microbiome and bowel symptoms in IBS, underscoring the importance of personalized strategies for its management.

Confectionary products hold promise as unconventional food carriers for probiotic microorganisms. This study explored the delivery of Heyndrickxia coagulans SNZ1969, a spore-forming probiotic, using gummy candies. In this study, we prepared gummy candies containing bacterial spores with a viable count that remained stable during a 24-month shelf-life period, meeting the label claim of at least one billion CFUs per serving (24 g). Then, we carried out an intervention trial involving 24 healthy adults who consumed one serving per day for two weeks followed by an additional two weeks of follow-up. Fecal samples were collected and analyzed with a protocol that allowed the viable counts of SNZ1969, both in spore and vegetative forms. The obtained results revealed that bacterial spores germinated in all volunteers. SNZ1969 persistence in the gut was monitored for two weeks after the end of gummy candy consumption, indicating its potential for prolonged colonization. These findings highlight the potential of unconventional food carriers for probiotic delivery and suggest that spore-forming probiotics can be metabolically active in the human intestine. These findings provide information for the development of food products containing spore-forming probiotics and their potential benefits in promoting gastrointestinal health.

Advanced glycation end products (AGEs) exert a key pathogenic role in the development of obesity and insulin resistance. Thanks to its abundance in bioactive compounds, the microalga Arthrospira platensis (spirulina, SP) is proposed as a nutritional supplement. Here, we investigated the potential anti-glycating properties of SP enriched with zinc (Zn-SP) and the following impact on diet-induced metabolic derangements. Thirty male C57Bl6 mice were fed a standard diet (SD) or a high-fat high-sugar diet (HFHS) for 12 weeks, and a subgroup of HFHS mice received 350 mg/kg Zn-SP three times a week. A HFHS diet induced obesity and glucose intolerance and increased plasma levels of pro-inflammatory cytokines and transaminases. Zn-SP administration restored glucose homeostasis and reduced hepatic dysfunction and systemic inflammation. In the liver of HFHS mice, a robust accumulation of AGEs was detected, paralleled by increased expression of the main AGE receptor (RAGE) and depletion of glyoxalase-1, whereas Zn-SP administration efficiently prevented these alterations reducing local pro-inflammatory responses. 16S rRNA gene profiling of feces and ileum content revealed altered bacterial community structure in HFHS mice compared to both SD and HFHS + Zn-SP groups. Overall, our study demonstrates relevant anti-glycation properties of Zn-SP which contribute to preventing AGE production and/or stimulate AGE detoxification, leading to the improvement of diet-related dysbiosis and metabolic derangements.

The gut microbiota is essential for many aspects of host physiology, and secretory immunoglobulin A (sIgA) modulates its function. The microbiota community determines the efficacy of immune checkpoint blockade (ICB) in cancer immunotherapy; however, mechanisms able to improve this function are not known. Extracellular adenosine triphosphate (ATP) released by the microbiota restricts the sIgA repertoire by limiting T follicular helper (T _FH ) cell activity in the Peyer’s patches via stimulation of the ionotropic P2X7 receptor. We show that sIgA amplification by oral administration of the ATP hydrolyzing enzyme apyrase corrects enteropathic features of ICB and improves therapeutic efficacy. Consistent with sIgA function in reshaping the gut ecosystem and enhancing ICB, IgA ^−/− mice did not show any improvement of antitumor response by apyrase administration. Mechanistically, data in mice and patients with cancer suggest that invigorated enterotropic cytotoxic T cells expressing the chemokine receptor CCR9 replenish the tumor microenvironment in a CCL25-mediated manner and control tumor growth, resulting in improved ICB efficacy.

Background: Heyndrickxia coagulans has emerged as a candidate for oral health applications, and chewing gum offers a promising delivery method. This study evaluates whether H. coagulans delivered via sugar-free chewing gum can induce detectable changes in plaque microbial ecology. Methods: A randomized, double-blind, placebo-controlled clinical trial was conducted on 52 healthy adults. Participants consumed probiotic or control gum for 4 weeks. Dental plaque was collected at baseline (T₀), mid-intervention (T₁), end of intervention (T₂), and one week post-intervention (T₃). qPCR quantified H. coagulans, while 16S rRNA gene profiling assessed microbial diversity and taxonomic composition. Statistical analyses included rank-based difference-in-differences models, Wilcoxon and Mann–Whitney tests, and differential abundance inference based on negative binomial modeling. Results: Forty-four subjects completed the study. In the Intervention group, the strain was detected in 71.4% of participants at T₁ and 61.9% at T₂, and it persisted in 9.5% at T₃. Differential abundance analysis revealed a broad depletion of taxa linked to oral dysbiosis at T₂ with partial persistence at T₃, along with selective enrichment of beneficial strains. Conclusions: H. coagulans delivered via chewing gum can reach the dental biofilm and induce modest, transient shifts in microbial composition. However, these biofilm ecology findings should be interpreted in the context of clinical outcomes.