Background: Gastrointestinal (GI) health is an important aspect of general health. Gastrointestinal symptoms are of specific importance for the elderly, an increasing group globally. Hence, promoting the elderly’s health and especially gastrointestinal health is important. Gut microbiota can influence gastrointestinal health by modulation of the immune system and the gut–brain axis. Diverse gut microbiota have been shown to be beneficial; however, for the elderly, the gut microbiota is often less diverse. Nutrition and physical activity, in particular, are two components that have been suggested to influence composition or diversity. Materials and Methods: In this study, we compared gut microbiota between two groups of elderly individuals: community-dwelling older adults and physically active senior orienteering athletes, where the latter group has less gastrointestinal symptoms and a reported better well-being. With this approach, we explored if certain gut microbiota were related to healthy ageing. The participant data and faecal samples were collected from these two groups and the microbiota was whole-genome sequenced and taxonomically classified with MetaPhlAn. Results: The physically active senior orienteers had a more homogeneous microbiota within the group and a higher abundance of Faecalibacterium prausnitzii compared to the community-dwelling older adults. Faecalibacterium prausnitzii has previously shown to have beneficial properties. Senior orienteers also had a lower abundance of Parasutterella excrementihominis and Bilophila unclassified, which have been associated with impaired GI health. We could not observe any difference between the groups in terms of Shannon diversity index. Interestingly, a subgroup of community-dwelling older adults showed an atypical microbiota profile as well as the parameters for gastrointestinal symptoms and well-being closer to senior orienteers. Conclusions: Our results suggest specific composition characteristics of healthy microbiota in the elderly, and show that certain components of nutrition as well as psychological distress are not as tightly connected with composition or diversity variation in faecal microbiota samples.

Anastomotic leakage is a major complication following colorectal surgery leading to peritonitis, complications, and mortality. Akkermansia muciniphila has shown beneficial effects on the gut barrier function. Whether A. muciniphila reduces peritonitis and mortality during colonic leakage is unknown. Whether A. muciniphila can directly modulate the expression of genes in the colonic mucosa in humans has never been studied. We investigated the effects of a pretreatment (14 days) with live A. muciniphila prior to surgical colonic perforation on peritonitis, mortality, and wound healing. We used mice with an inducible intestinal-epithelial-cell-specific deletion of MyD88 (IEC-MyD88 KO) to investigate the role of the innate immune system in this context. In a proof-of-concept pilot study, healthy humans were exposed to A. muciniphila for 2 h and colonic biopsies taken before and after colonic instillation for transcriptomic analysis. Seven days after colonic perforation, A.-muciniphila-treated mice had significantly lower mortality and severity of peritonitis. This effect was associated with significant improvements of wound histological healing scores, higher production of IL22, but no changes in the mucus layer thickness or genes involved in cell renewal, proliferation, or differentiation. All these effects were abolished in IEC-MyD88 KO mice. Finally, human subjects exposed to A. muciniphila exhibited an increased level of the bacterium at the mucus level 2 h after instillation and significant changes in the expression of different genes involved in the regulation of cell cycling, gene transcription, immunity, and inflammation in their colonic mucosa. A. muciniphila improves wound healing during transmural colonic wall defect through mechanisms possibly involving IL22 signaling and requiring MyD88 in the intestinal cells. In healthy humans, colonic administration of A. muciniphila is well tolerated and changes the expression of genes involved in the immune pathways.

An altered immune response and gut microbiota have been associated with the pathology of Inflammatory Bowel Diseases (IBD). However, there is limited knowledge of how inflammation is associated with changes in the microbiota. We studied the microbiota in the intestine and faeces as well as the cytokine gene expressions in caecum and colon of a mouse model (Gαi2^−/−) of colitis, and analysed them in relation to the degrees of inflammation in the colon. The degree of colitis was associated with general changes in the complexity of the microbiota and was corroborated by quantitative analyses of the Bacteroides and Lactobacillus. High gene expression levels of IL-17 and IFN-γ in colon and caecum were detected in Gαi2^−/− mice with moderate and severe colitis. High IL-27 gene expression in the colon of mice with moderate and severe colitis and in the caecum of mice with moderate colitis was also detected. Negative correlations between IL-27 and Bacteroides and Lactobacillus and between IFN-γ and Lactobacillus were detected in caecum. This research indicates that the degree of colitis in IBD correlates with the gene expression of cytokines and with disturbances in the gut microbiota. Furthermore, the caecum could have an important role in the pathology of IBD.

Aim: The cell matrix of plant foods has received little attention in prebiotic fiber research. We aimed to understand the impact of the plant cell matrix in dried chicory root on its breakdown in the human gut to explain its reported beneficial effects on gut and metabolic health. Methods: We applied in vitro digestion and fermentation models together with an ex vivo gut barrier integrity model. Plant cell matrix intactness in the upper gastrointestinal tract was investigated by scanning electron microscopy. Colonic breakdown of inulin, and chicory root cubes and powder was assessed by gut microbiota analysis using 16S rRNA gene amplicon sequencing and determining the kinetics of changes in pH, gas, and short-chain fatty acid production (SCFA). Finally, effects on gut barrier integrity were explored by exposing colonic biopsies to fermentation supernatants in an Ussing chamber model. Results: The plant cell matrix of dried chicory root cubes remained intact throughout upper gastrointestinal transit. Dried chicory root fermentation resulted in higher final relative abundances of pectin-degrading Monoglobus and butyrate-producing Roseburia spp. compared to inulin and a seven-fold increase in Bifidobacterium spp. in donors where these species were present. Dried chicory root cubes yielded similar total SCFAs but higher final butyrate levels than chicory root powder or isolated inulin with less gas produced. No uniform but donor-specific effects of fermentation supernatants on the maintenance of gut barrier integrity were detected. Conclusion: The intact plant cell matrix of dried chicory root affected its colonic breakdown kinetics and microbiota, underpinning its beneficial effect in vivo .

Background: This study investigates the impact of fermentation supernatants (FSs) from Pleurotus eryngii whole mushrooms (PEWS), as well as its subcomponents, digested (PEWSD) and extracted (PEWSE) forms, on intestinal barrier function and immune modulation in lipopolysaccharide (LPS) -stimulated Caco-2 cells. Methods: Gene expression of tight junction (TJs) genes, cytokines, and key immune/metabolic receptors was assessed via qRT-PCR, while cytokine protein levels were measured using ELISA to explore post-transcriptional regulation. Results: LPS challenge significantly downregulated TJs zonula occludens-1 (ZO-1,) occludin, and claudin-1, compromising epithelial integrity. Treatment with FS-PEWS notably restored ZO-1 and occludin expression, outperforming FS-PEWSD and FS-PEWSE, which only partially mitigated the LPS-induced damage. FS-PEWS further demonstrated potent immunomodulatory effects, upregulating anti-inflammatory IL-10 and pro-inflammatory cytokines such as IL-8 and TNF-α. The activation of key receptors like TLR-2 and mTOR suggests that FS-PEWS modulates critical immune and metabolic pathways, such as NF-kB signaling, to maintain immune homeostasis. Although mRNA expression of pro-inflammatory cytokines was altered, no corresponding protein release was detected, suggesting potential post-transcriptional regulation. Conclusions: FS-PEWS preserves intestinal barrier integrity and modulates immune responses, particularly in low-grade inflammation, highlighting the whole food matrix’s role in enhancing its bioactivity and functional food potential.