Vitamin–Microbiota Crosstalk in Intestinal Inflammation and Carcinogenesis

Gut-brain communication mediates the impact of dietary lipids on cognitive capacity

Cognitive impairment, as a prevalent symptom of nervous system disorders, poses one of the most challenging aspects in the management of brain diseases. Lipids present in the cell membranes of all neurons within the brain and dietary lipids can regulate the cognition and memory function. In recent years, the advancements in gut microbiome research have enabled the exploration of dietary lipids targeting the gut-brain axis as a strategy for regulating cognition. This present review provides an in-depth overview of how lipids modulate cognition via the gut-brain axis depending on metabolic, immune, neural and endocrine pathways. It also comprehensively analyzes the effects of diverse lipids on the gut microbiota and intestinal barrier function, thereby affecting the central nervous system and cognitive capacity. Moreover, comparative analysis of the positive and negative effects is presented between beneficial and detrimental lipids. The former encompass monounsaturated fatty acids, short-chain fatty acids, omega-3 polyunsaturated fatty acids, phospholipids, phytosterols, fungal sterols and bioactive lipid-soluble vitamins, as well as lipid-derived gut metabolites, whereas the latter (detrimental lipids) include medium- or long-chain fatty acids, excessive proportions of n-6 polyunsaturated fatty acids, industrial trans fatty acids, and zoosterols. To sum up, the focus of this review is on how gut-brain communication mediates the impact of dietary lipids on cognitive capacity, providing a novel theoretical foundation for promoting brain cognitive health and scientific lipid consumption patterns.

Intestinal Microbiomics and Metabolomics Insights into the Hepatoprotective Effects of Lactobacillus paracasei CCFM1222 Against the Acute Liver Injury in Mice

In recent years, acute liver injury (ALI) has received wide-range attention in the world due to its relatively high morbidity and mortality. This study aimed to explore the hepatoprotective effect of Lactobacillus paracasei CCFM1222 against lipopolysaccharide (LPS)-induced ALI mice and further elaborate its mechanism of action from the perspective of intestinal microbiomics and metabolomics. The results displayed that L. paracasei CCFM1222 pretreatment significantly decreased the serum ALT, and AST levels, inhibited the releases of hepatic TNF-α, IL-1β, and IL-6 levels, and activated the SOD, CAT, and GSH-Px activities in LPS-treated mice. The cecal short-chain fatty acid (SCFAs) levels were increased in LPS-treated mice with L. paracasei CCFM1222 pretreatment. In addition, L. paracasei CCFM1222 pretreatment remarkably shifted the intestinal microbiota composition, including the higher abundance of Faecalibaculum, Bifidobacterium, and lower abundance of the Prevotellaceae NK3B31 group, which is positively associated with the cecal propionic, butyric, valeric, isobutyric, and isovaleric acids. The metabolomics based on UPLC-QTOF/MS revealed that L. paracasei CCFM1222 pretreatment significantly regulated the composition of feces metabolites in LPS-treated mice, especially the potential biomarker-related butanoate metabolism, vitamin B6 metabolism, D-glutamine and D-glutamate metabolism, tryptophan metabolism, caffeine metabolism, arginine biosynthesis, arginine, and proline metabolism. Moreover, L. paracasei CCFM1222 pretreatment remarkably regulated the expression of gene-associated ALI (including Tlr4, Myd88, Nf-kβ, iNOS, Cox2, Iκ-Bα, Nrf2, and Sirt-1). In conclusion, these results suggest the possibility that L. paracasei CCFM1222 supplementation has beneficial effects on preventing the occurrence and development of ALI by inhibiting the inflammatory responses and altering intestinal microbiota composition and their metabolites.

Tumorigenesis in Inflammatory Bowel Disease: Microbiota-Environment Interconnections

Colo-rectal cancer (CRC) is undoubtedly one of the most severe complications of inflammatory bowel diseases (IBD). While sporadic CRC develops from a typical adenoma-carcinoma sequence, IBD-related CRC follows different and less understood pathways and its pathophysiological mechanisms were not completely elucidated. In contrast to chronic inflammation, which is nowadays a well-recognised drive towards neoplastic transformation in IBD, only recently was gut microbiota demonstrated to interfere with both inflammation processes and immune-mediated anticancer surveillance. Moreover, the role of microbiota appears particularly complex and intriguing when also considering its multifaceted interactions with multiple environmental stimuli, notably chronic pathologies such as diabetes and obesity, lifestyle (diet, smoking) and vitamin intake. In this review, we presented a comprehensive overview on current evidence of the influence of gut microbiota on IBD-related CRC, in particular its mutual interconnections with the environment.

Vitamin D and Microbiome: Molecular Interaction in Inflammatory Bowel Disease Pathogenesis

Studies of systemic autoimmune diseases point to characteristic microbial patterns in various diseases, including inflammatory bowel disease (IBD). Autoimmune diseases, and IBD in particular, show a predisposition to vitamin D deficiency, leading to alterations in the microbiome and disruption of intestinal epithelial barrier integrity. In this review, we examine the role of the gut microbiome in IBD and discuss how vitamin D-vitamin D receptor (VDR)-associated molecular signaling pathways contribute to the development and progression of IBD through their effects on gut barrier function, the microbial community, and immune system function. The present data demonstrate that vitamin D promotes the proper function of the innate immune system by acting as an immunomodulator, exerting anti-inflammatory effects, and critically contributing to the maintenance of gut barrier integrity and modulation of the gut microbiota, mechanisms that may influence the IBD development and progression. VDR regulates the biological effects of vitamin D and is related to environmental, genetic, immunologic, and microbial aspects of IBD. Vitamin D influences the distribution of the fecal microbiota, with high vitamin D levels associated with increased levels of beneficial bacterial species and lower levels of pathogenic bacteria. Understanding the cellular functions of vitamin D-VDR signaling in intestinal epithelial cells may pave the way for the development of new treatment strategies for the therapeutic armamentarium of IBD in the near future.

Enhancing intestinal barrier efficiency: A novel metabolic diseases therapy

Physiologically, the intestinal barrier plays a crucial role in homeostasis and nutrient absorption and prevents pathogenic entry, harmful metabolites, and endotoxin absorption. Recent advances have highlighted the association between severely damaged intestinal barriers and diabetes, obesity, fatty liver, and cardiovascular diseases. Evidence indicates that an abated intestinal barrier leads to endotoxemia associated with systemic inflammation, insulin resistance, diabetes, and lipid accumulation, accelerating obesity and fatty liver diseases. Nonetheless, the specific mechanism of intestinal barrier damage and the effective improvement of the intestinal barrier remain to be explored. Here, we discuss the crosstalk between changes in the intestinal barrier and metabolic disease. This paper also highlights how to improve the gut barrier from the perspective of natural medicine, gut microbiota remodeling, lifestyle interventions, and bariatric surgery. Finally, potential challenges and prospects for the regulation of the gut barrier-metabolic disease axis are discussed, which may provide theoretical guidance for the treatment of metabolic diseases.