Bioscience of microbiota, food and health最新文献

High-fat diet (HFD)-induced alterations in gut microbiota may be associated with host pathophysiology, prompting increased interest in elucidating their causal relationships. However, the mechanisms by which HFDs induce these alterations require further clarification. Our previous study using cholic acid (CA)-fed rats suggested that bile acid drives the HFD-induced microbiota alterations as a host factor, a concept termed the "bile acid hypothesis". We analyzed the alterations in the cecal microbiota and bile acid composition in HFD-fed rats and compared the results with those of rats on a CA-supplemented diet. In both cases, the concentrations of total bile acids, including highly bactericidal deoxycholic acid (DCA), increased, concomitant with the increases in the Firmicutes (Bacillota)/Bacteroidetes (Bacteroidota) ratio. Operational taxonomic units (OTUs), accounting for 63.39% of the cecal microbiota of control rats, showed a significant correlation with the total bile acid concentration in HFD-fed rats. A DCA sensitivity test conducted in Firmicutes isolates, corresponding to the predominant OTUs from the HFD-fed rats, exhibited significantly higher DCA resistance compared with Bacteroidetes. The top 12 most abundant OTUs of Firmicutes and Bacteroidetes showing positive or negative correlations with the total bile acid concentration were selected from the HFD-fed rats, and their dynamics were compared with those in the CA-fed rats. Of the 24 OTUs, 18, which constituted 48.28% of the cecal population in the control rats, were altered in the same direction (increase or decrease) in the HFD- and CA-supplemented diet groups. Therefore, approximately half of the cecal populations in the control rats were affected by bile acids, substantiating the bile acid hypothesis microbiologically and quantitatively.

To observe the composition and abundance of the intestinal flora in patients with Wilson disease (WD)-related liver fibrosis and analyze the correlation between the composition of intestinal flora of patients and the evolution of evidence from Chinese medicine, we selected 237 patients with WD-related liver fibrosis and 30 healthy volunteers from the Brain Disease Center of Anhui Provincial Hospital of Chinese Medicine. The patients with WD-related liver fibrosis were divided into 5 groups according to traditional Chinese medicine (TCM) evidence (dampness-heat syndrome, group A; intermingled phlegm and blood stasis syndrome, group B; liver wind stirring up internally syndrome, group C; yin deficiency of the liver and kidney syndrome, group D; and yang deficiency of the spleen and kidney syndrome, group E) and a group healthy volunteers (group F), which served as the control. Stool samples were obtained from the patients in the 6 groups. The 16S rRNA sequencing technique was used to analyze the intestinal flora of the different TCM evidence groups of WD patients and the healthy control group and subjected to a statistical analysis. The intestinal flora abundance was significantly lower in patients with WD-related liver fibrosis than in healthy controls, and the decrease in strain content was more significant in patients with deficiency evidence in groups D and E. In terms of the structure of the phylum-level flora, the Firmicutes phylum was still the dominant phylum, but the contents of the evidence-type groups all decreased, with the most obvious decreases in groups D and E. The results for the Actinobacteria phylum were similar, whereas the opposite was true for the Proteobacteria phylum. The section-level and genus-level results corresponded to the gate level. The intestinal flora of the WD-related liver fibrosis patients and healthy controls differed in terms of abundance and intestinal flora structure, and there were also differences between different Chinese medicine certificates.

Immunoglobulin (Ig) G isotypes in the sera of healthy mice and humans react to commensal bacteria. We previously reported that BALB/c mice with normal gut microbiota possessed abundant B cells that produced IgG2b reactive to commensal bacteria in cecal patches (CePs), indicating a potential source of a systemic pool of commensal bacteria-reactive IgG2b. Mice housed under germ-free conditions demonstrate the importance of the gut microbiota in driving cecal IgG2b responses. However, it is unclear whether the constitutive presence of the gut microbiota and specific bacterial taxa are important for IgG2b responses in adult mice. In this study, we showed that elimination of the gut microbiota by mixed antibiotic treatment in adult mice decreased the abundance of IgG2b⁺ B cells, follicular helper T (Tfh) cells in CePs, and the serum levels of commensal bacteria-reactive IgG2b. Reduced IgG2b responses have also been observed in mice with an altered gut microbiota following treatment with ampicillin or vancomycin. Changes in the diversity and composition of the cecal microbiota, particularly a decrease in Lachnospiraceae, Muribaculaceae, Ruminococcaceae, and Bacteroidaceae abundance at the family level, were observed in these mice. In addition, depletion of CD4⁺ T cells by the injection of neutralizing antibodies in adult mice reduced IgG2b responses. Our results suggest that specific gut bacteria susceptible to ampicillin and vancomycin play roles in providing an abundance of Tfh cells to help the generation of IgG2b⁺ B cells in CePs in adult mice, which may contribute to the supply of systemic commensal bacteria-reactive IgG2b.

Fructobacillus spp. comprise a large genus of fructophilic lactic acid bacteria whose growth characteristics differ from those of other common lactic acid bacteria. The genus has been extensively investigated microbiologically and phylogenetically. However, knowledge regarding Fructobacillus nutritional benefits remains unclear. In particular, Fructobacillus fructosus OS-1010 (OS-1010) was recently shown to act on intestinal cells to release extracellular vesicle exosomes that act on distant target cells. The released exosomes reportedly enhanced the expression of longevity-associated genes and intracellular mitochondrial activity in muscle cells. OS-1010 is expected to be a functional ingredient that improves the function of distant tissues such as muscles and skin upon oral intake. This study examined the effects of the oral intake of heat-killed OS-1010 on human skin in a randomized, double-blind, placebo-controlled, parallel-group study of healthy participants. Significant improvement in skin elasticity was observed after eight weeks of oral OS-1010 intake. Furthermore, although no significant difference was found between the two groups in a wrinkle-related parameter, the OS-1010 group demonstrated improvements in the percentage wrinkle area and overall average wrinkle depth of crow's feet, which were not observed in the placebo group. These results indicate that OS-1010 can contribute to the improvement in skin conditions.

The study of the relationships between the microbiota and intestinal environment of companion animals has gained increasing attention, particularly concerning health and disease. Previously, we demonstrated that continuous intake of galacto-oligosaccharides (GOS), a prebiotic, can improve the health of household dogs by modulating their gut microbiota. Given the potential health benefits of GOS in cats, we conducted a single-arm open-label study to evaluate the effects of a GOS-containing syrup on the gut microbiota and its metabolites in healthy cats. The study included 25 household cats and was conducted over 12 weeks. Each cat was fed 1.2 g of a GOS-containing syrup per day, equivalent to 0.5 g of GOS. Before the start of the study (week 0), during the 8-week intake period (weeks 4 and 8), and 4 weeks after the intake period (week 12), fecal microbiota, fecal organic acid and putrefactive product concentrations, fecal odor, and serum uremic toxin concentrations were assessed. The results showed that the levels of acetic acid-producing Bifidobacteriaceae significantly increased as a result of GOS intake. Additionally, Peptostreptococcaceae and Eggerthellaceae levels significantly decreased and increased, respectively, due to GOS intake. Furthermore, the concentrations of acetic, propionic, and n-butyric acids in feces significantly increased, whereas serum phenyl sulfate levels decreased significantly. These findings suggested that continuous GOS intake may contribute to the health of household cats.

Due to the requirement for a novel and effective treatment for non-alcoholic fatty liver disease (NAFLD), this study aimed to determine the effects of a novel supplement containing Lactocaseibacillus zeae and Limosilactobacillus reuteri on oxidative stress, inflammation, glucose and lipid metabolism, lipid accumulation, and liver function in the fructose-induced NAFLD rat model. To investigate the involvement of molecular pathways and validate a preclinical study, NAFLD was induced by feeding them fructose-containing drinking water (20% w/v) for 12 consecutive weeks. The fructose-induced male rats were administered a mixture of L. zeae TISTR 2529 and L. reuteri TISTR 2736 at a dose of 2 × 10⁸ CFU/mL during weeks 0 to 12, daily. Weight and food intake were recorded daily. The production of oxidative stress, expression of the TNF-α, SREBP-1c, liver enzymes, and lipid profiles, including the densities of lipid droplets in liver cells, were also evaluated. The results revealed that fructose-induced rats co-treated with the mixed probiotics had significantly decreased body weights, triglycerides, cholesterol, and liver enzymes. Furthermore, the expression of TNF-α, MDA, and SREBP-1c and the densities of lipid droplets in the liver tissue were reduced. Based on the results, the novel probiotic supplement containing L. zeae TISTR 2529 and L. reuteri TISTR 2736 might alleviate NAFLD by normalizing oxidative stress, inflammation, lipid metabolism, and lipid accumulation in the liver of NAFLD-induced model rats.

The gastrointestinal tract is an ecosystem with heterogeneous patterns, distributions, and environments, resulting in different microbial compositions in each gut segment. The relationship between diet and microbiota determines this heterogeneity. Consumption of diets high in fat and carbohydrates (HLHC) is associated with gut dysbiosis, low microbial diversity, and metabolic syndrome (MetS). Functional fiber consumption improves the profile and diversity of the gut microbiota (GM); it stimulates the production of short-chain fatty acids (SCFAs), which act as signaling molecules that maintain the gut barrier integrity and induce hormone synthesis that regulates satiety and glucose metabolism, reducing some MetS parameters. The effect of a dietary intervention with Acanthocereus tetragonus (At), a cactus rich in fiber, antioxidants, amino acids, and minerals traditionally consumed by the Mexican population, is reported here. For this purpose, Wistar rats were randomly divided into three study groups: a control (C) group, a MetS group, and an At-supplemented group. In the MetS and At groups, an HLHC was administered for 12 weeks, inducing MetS. After 18 weeks, stool samples were collected for microbiota sequencing. HLHC administration favored Firmicutes and decreased the abundance of Bacteriodetes at the phylum level in the MetS group. At the genus level, the dietary intervention with At increased the presence of Roseburia, Ruminococcus, Blautia, Bacteroides, and Christensenella, reflecting the effect of A. tetragonus consumption on GM. At diet administration reduced body weight; the plasma glucose, insulin, and lipid levels; and insulin resistance.

In recent years, the gut microbiota has attracted attention due to reported associations with various diseases and health conditions. Gut bacteria have been constantly cultured at 37°C, potentially limiting the understanding of the interaction between them and the host. However, the most dominant human gut microbial species have not been extensively cultured at temperatures other than 37°C. In this study, we analyzed the effects of various culturing temperatures on the growth of the 51 most dominant commensal species as well as 3 harmful bacteria, including Clostridium perfringens, a food poisoning bacterium, in the human intestine. The results showed that the growth of predominant gut microbes varied minimally at body temperatures conducive to human survival but that the growth of several bacteria involved in butyrate production in the intestinal lumen was repressed at temperatures other than 37°C. When cultured at 50°C, the growth of C. perfringens was less inhibited than that of other bacterial species. In addition, the growth of some gut bacteria was unaffected by a body temperature range that was not suitable for human survival.

Protecting brain health is one of the current focal points of public concern. Medicinal foods that promote brain health, such as Gastrodia elata Bl, black sesame seeds (Sesamum indicum L.), walnuts (Juglans regia L.), jujube (Ziziphus jujuba Mill.), Poria cocos, and Coix seeds, possess antioxidant and neuroprotective properties, as well as modulating effects on the intestinal microbiota. This study evaluated the effects of functional biscuits formulated with these medicinal foods on the intestinal mucosal microbiota, brain function, and antioxidant activity in mice. Forty male SPF-grade C57BL/6J mice were randomly divided into a blank control group (NG), low-dose functional biscuit group (GLG), medium-dose functional biscuit group (GMG), and high-dose functional biscuit group (GHG). After 42 days of continuous feeding with the functional biscuits, changes in the richness, diversity, and community structure of the intestinal mucosal microbiota were observed. Compared with the NG group, norepinephrine (NE) levels in the hippocampus significantly increased in the GLG, GMG, and GHG groups, while gamma-aminobutyric acid (GABA) levels showed no significant difference. In the GMG and GHG groups, malondialdehyde (MDA) levels in the liver significantly decreased, and acetylcholine transferase (ChAT) levels in the hippocampus significantly increased. Additionally, multiple bacterial genera were found to be correlated with the NE, ChAT, and MDA levels. These findings indicate that functional biscuits have effects on modulating the intestinal mucosal microbiota composition, enhancing brain function, and exhibiting antioxidant activity, making them a beneficial functional food for brain health.

Single-strain Bifidobacterium species are commonly used as probiotics with low birth weight neonates. However, the effectiveness and safety of multi-strain Bifidobacterium supplementation are not well known. Thirty-six neonates weighing less than 2,000 g (558-1,943 g) at birth and admitted to a neonatal intensive care unit were randomly assigned to receive a single strain or triple strains of Bifidobacterium with lactulose enterally for 4 weeks from birth. The relative abundances of Staphylococcus and Bifidobacterium in the fecal microbiota at weeks 1, 2, and 4 were investigated. Based on the study results, no significant difference was detected between the two groups in the abundance of Staphylococcus; however, the triple-strain group had significantly high abundances of Bifidobacterium at weeks 2 and 4. The fecal microbiota in the triple-strain group had significantly lower alpha diversity (Bifidobacterium-enriching) after week 4 and was different from that in the single-strain group, which showed a higher abundance of Clostridium. No severe adverse events occurred in either group during the study period. Although no significant difference was detected between single- and multi-strain bifidobacteria supplementation in the colonization of Staphylococcus in the fecal microbiota of the neonates, multi-strain bifidobacteria supplementation contributed toward early enrichment of the microbiota with bifidobacteria and suppression of other pathogenic bacteria, such as Clostridium spp.