Chemomicrobiome analysis of the ornithine molecule

Hepatoprotectors and prebiotic molecules that promote the growth of intestinal flora differ significantly in their effects on different representatives of the human microbiome. This work presents the results of a comparative chemomicrobiomic analysis of ornithine and reference molecules (S-ademetionine, ursodeoxycholic acid, lactulose, and fructose). For each of the studied molecules, estimates of the values of the area under the growth curve were obtained for a representative sample of human microbiota, which included 38 commensal bacteria (including bifidobacteria and lactobacilli) and the values of the minimum inhibitory concentrations (MIC) for 152 strains of pathogenic bacteria. It has been shown that ornithine, to a lesser extent than the reference molecules, stimulates the growth of pathogenic bacteria of the genera Aspergillus, Klebsiella, Pseudomonas, Staphylococcus and Candida fungi. Ornithine is also less likely to stimulate the growth of more aggressive bacteria (Biosafety Level 2) and to a greater extent less aggressive bacteria (Biosafety Level 1). By stimulating butyric and other short-chain fatty acid-producing microorganisms, ornithine can improve the profile of gut microbiota.

Dietary Vegetable Powders Modulate Immune Homeostasis and Intestinal Microbiota in Mice

As the largest immune organ of the human body, the intestine also plays a vital role in nutrient digestion and absorption. Some vegetables are considered to have improvement effects on the intestine. This experiment explored the effects of freeze-dried asparagus, broccoli and cabbage powder on the intestinal immune homeostasis and microflora of mice. Thirty-two mice were divided into four groups (n = 8), including control group (fed normal diet), asparagus group (fed normal diet with 5% asparagus power), broccoli group (fed normal diet with 5% broccoli power) and cabbage group (fed normal diet with 5% cabbage power). The experiment lasted 21 days. The results showed that the serum immunoglobulin concentration (IgA and IgM) and intestinal cytokine content (like IFN-γ and TNF-α) were increased after vegetable powder supplement. The experiment also detected that vegetable powder supplementation changed intestinal flora and their metabolites (short-chain fatty acid), which showed that the abundance of Lachnospiraceae and Bacteroides were decreased, while the abundance of Firmicutes and Lactobacillus as well as propionic acid and butyric acid contents were increased. Together, these vegetable powders, especially cabbage, changed the intestinal immune response and microbial activity of mice.

Effects of Lactobacillus plantarum FZU3013-Fermented Laminaria japonica on Lipid Metabolism and Gut Microbiota in Hyperlipidaemic Rats

In this study, we explored the effect of Lactobacillus plantarum FZU3013-fermented Laminaria japonica (LPLJ) supplementation to prevent hyperlipidaemia in rats fed with a high-fat diet (HFD). The results indicate that LPLJ supplementation improved serum and hepatic biochemical indicators (p < 0.05), elevated short-chain fatty acid levels, reduced HFD-induced accumulation of lipid droplets in the liver, modulated the relative abundance of some microbial phylotypes, and reduced hyperlipidaemia in HFD-fed rats by adjusting the aminoacyl-tRNA, phenylalanine, tyrosine, and tryptophan biosynthetic pathways, as well as the phenylalanine, D-glutamine and D-glutamate, and glutathione metabolic pathways. Additionally, hepatic mRNA levels of the genes involved in lipid metabolism and bile acid homeostasis were significantly reduced by LPLJ intervention (p < 0.05). These results suggest that LPLJ has a positive effect on modulating lipid metabolism and has the potential to be a functional food that can help prevent hyperlipidaemia.

Comparison of Bacterial Composition, Concentration, and Metabolism of Short Chain Fatty Acid in Inflammatory Bowel Disease: A Systematic Review

Inflammatory bowel disease (IBD), which consists of Crohn's disease (CD) and ulcerative colitis (UC), is a chronic inflammatory disorder of the intestine. The etiology is heterogeneous and multifactorial, including genetic susceptibility, immune-mediated tissue damage, and changes of lumen microenvironment, especially short-chain fatty acid (SCFA) producing bacteria. Several studies reported a decrease in SCFA concentration in both CD and UC. In fact, SCFAs has important roles in accelerating disease remission. This systematic review aimed to evaluate the changes in SCFA concentration, the composition of SCFA-producing bacteria, and SCFA metabolism in IBD. A literature search was conducted via PubMed, Scopus, and CENTRAL by selecting studies according to inclusion and exclusion criteria. The quality and risk of bias assessment were performed using the Newcastle-Ottawa Scale (NOS). Overall, 160 UC and 127 CD patients from 5 studies were reviewed. The SCFA concentration was significantly reduced (p <0.05) in both PC and UC. Moreover, there was a decrease in major SCFA-producing bacteria. Clostridium coccoides were significantly decreased in the feces of active UC (p = 0.015) and CD (p = 0.04). Clostridium leptum was decreased on intestinal mucosal biopsy of active CD and UC (p <0.0001). Faecalibacterium prausnitzii were decreased in active CD faeces (p <0.0001) and UC (p = 0.0001). Butyrate oxidation rate was also reported to decrease in UC compared to control (p<0.0001). In conclusion, the ability of major SCFA-producing bacterial production in IBD was diminished, which implies a decreased protective and anti-inflammatory effect of SCFA that altered its metabolism.

Lactoferrin Ameliorates Dry Eye Disease Potentially through Enhancement of Short-Chain Fatty Acid Production by Gut Microbiota in Mice

Lactoferrin is a glycoprotein found at high concentrations within exocrine secretions, including tears. Low levels of lactoferrin have been implicated in the loss of tear secretion and ageing. Furthermore, lactoferrin possesses a range of functionalities, including anti-inflammatory properties and the ability to modulate the gut microbiota. Expanding evidence demonstrates a crucial role of the gut microbiota in immune regulation and development. The specific composition of bacterial species of the gut has a profound influence on local and systemic inflammation, leading to a protective capacity against a number of inflammatory diseases, potentially by the induction of regulatory immune cells. In this study, we demonstrated that oral administration of lactoferrin maintains tear secretion in a restraint and desiccating stress induced mouse model of dry eye disease. Furthermore, we revealed that lactoferrin induces the reduction of inflammatory cytokines, modulates gut microbiota, and induces short-chain fatty acid production. Whereas, the antibiotic vancomycin abrogates the effects of lactoferrin on dry eye disease and significantly reduces short-chain fatty acid concentrations. Therefore, this protective effect of LF against a mice model of DED may be explained by our observations of an altered gut microbiota and an enhanced production of immunomodulatory short-chain fatty acids.

Comparison of Microbial Populations in Saliva and Feces from Healthy and Celiac Adolescents with Conventional and Molecular Approaches after Cultivation on Gluten-Containing Media: An Exploratory Study

Microbes capable of metabolizing gluten are common in various parts of the intestinal tract. In this study, saliva and fecal samples were obtained from 10 adolescents (13–18 years of age), five of which had celiac disease (CD) and five of which were healthy volunteers (HV). Culture-enriched saliva and fecal samples were compared with molecular profiling, and microorganisms displaying lysis zones on gluten-containing media (i.e., gluten-degrading microorganisms; GDMs) were isolated. In total, 45 gluten-degrading strains were isolated, belonging to 13 genera and 15 species, including Candida albicans and Veillonella. GDMs were more common in HVs compared to CD patients and more diverse in saliva compared to feces. In saliva, GDMs showed partial overlap between HVs and CD patients. Bacterial communities in fecal samples determined with amplicon sequencing significantly differed between CD patients and HVs. Overall, 7–46 of all operational taxonomic units (OTUs) per sample were below the detection limit in the fecal samples but were present in the cultivated samples, and mainly included representatives from Lactobacillus and Enterococcus. Furthermore, differences in fecal short-chain fatty-acid concentrations between CD patients and HVs, as well as their correlations with bacterial taxa, were demonstrated.