In Japan, the growing interest in anti-aging skin care is associated with the unprecedented aging society. Skin aging can be attributed to various factors, including the activation of hyaluronidase enzyme in subcutaneous tissues exposed to ultraviolet radiation. This enzyme breaks down hyaluronic acid, leading to skin sagging. Therefore, hyaluronidase inhibitors can effectively prevent skin aging. Previously, food components have been actively explored to search for hyaluronidase inhibitors considering the high safety of these materials. Although lactic acid bacteria (LAB)-fermented foods inhibit this enzyme, their active compounds responsible for hyaluronidase inhibition remain unknown. Thus, in this study, we aimed to explore the mechanism underlying the LAB-mediated inhibition of hyaluronidase activity. Supernatants of a LAB-fermented milk-based beverage were subjected to a hyaluronidase inhibition assay, followed by purification and separation using hydrophobic adsorbents and high-performance liquid chromatography, respectively. Subsequently, liquid chromatograph time-of-flight mass analysis was performed, revealing α-ketoglutarate (AKG) as the inhibitor of this enzyme. The half-maximal inhibitory concentration (IC₅₀) of AKG was approximately 0.13-fold that of the known strong hyaluronidase inhibitor disodium cromoglycate (DSCG). To the best of our knowledge, this is the first report on hyaluronidase inhibition mediated by AKG, a metabolic product of LAB. Additionally, Lactobacillus acidophilus JCM1132 was identified as a highly effective AKG-producing LAB (63.9 µg/mL) through LC-MS/MS-based quantitative analyses using various LAB-fermented milk samples. We anticipate that the findings of this study will potentially support the development of functional foods and cosmetics enriched with AKG.

Diverse bacterial and fungal microbiota communities inhabit the human body, and their presence is essential for maintaining host homeostasis. The oral cavity, lung, gut, and vagina are just a few of the bodily cavities where these microorganisms communicate with one another, either directly or indirectly. The effects of this interaction can be either useful or detrimental to the host. When the healthy microbial diversity is disturbed, for instance, as a result of prolonged treatment with broad spectrum antibiotics, this allows the growth of specific microbes at the expense of others and alters their pathogenicity, causing a switch of commensal germs into pathogenic germs, which could promote tissue invasion and damage, as occurs in immunocompromised patients. Consequently, antimicrobials that specifically target pathogens may help in minimizing secondary issues that result from the disruption of useful bacterial/fungal interactions (BFIs). The interface between Candida albicans and Aspergillus fumigatus with bacteria at various body sites is emphasized in the majority of the medically important BFIs that have been reported thus far. This interface either supports or inhibits growth, or it enhances or blocks the generation of virulence factors. The aim of this review is to draw attention to the link between the bacterial and fungal microbiota and how they contribute to both normal homeostasis and disease development. Additionally, recent research that has studied microbiota as novel antimicrobials is summarized.

Ischemic stroke (IS) is the predominant form of stroke pathology, and its clinical management remains constrained by therapeutic time frame. The gut microbiota (GM), comprising a multitude of bacterial and archaeal cells, surpasses the human cell count by approximately tenfold and significantly contributes to the human organism’s growth, development, and overall well-being. The microbiota-gut-brain axis (MGBA) in recent years has established a strong association between gut microbes and the brain, demonstrating their intricate involvement in the progression of IS. The regulation of IS by the GM, encompassing changes in composition, abundance, and distribution, is multifaceted, involving neurological, endocrine, immunological, and metabolic mechanisms. This comprehensive understanding offers novel insights into the therapeutic approaches for IS. The objective of this paper is to examine the mechanisms of interaction between the GM and IS in recent years, assess the therapeutic effects of the GM on IS through various interventions, such as dietary modifications, probiotics, fecal microbiota transplantation, and antibiotics, and offer insights into the potential clinical application of the GM in stroke treatment.

This study aimed to investigate the potential anti-obesity efficacy of Lactobacillus acidophilus CICC 6075. The study analyzed fecal metagenomic data from 120 obese and 100 non-obese individuals. C57BL/6 mice on normal diet or high-fat diet (HFD) were treated with L. acidophilus CICC 6075 by daily oral gavage for 12 weeks, followed by evaluations of the obesity phenotype. Metagenomic analysis revealed depletion of Lactobacillus acidophilus in obese individuals. Administration of L. acidophilus CICC 6075 attenuated excessive weight gain and fat accumulation and maintained the intestinal barrier in HFD-induced obese mice. Sequencing results showed that HFD hindered α- and β diversity while reducing the relative abundance of Lactobacillus and norank_f_Muribaculaceae and significantly increasing the relative abundance of Ileibacterium. L. acidophilus CICC 6075 reversed these results and reduced the Firmicutes/Bacteroidetes ratio. Supplementation of L. acidophilus CICC 6075 enhanced histidine biosynthesis, inhibited the NF-κB pathway, and significantly reduced the expression levels of inflammatory factors in adipose tissue. These results indicate that L. acidophilus CICC 6075 alleviates HFD-induced obesity in mice by inhibiting the activation of the NF-κB pathway and enhancing gut microbiota functionality. This suggests that L. acidophilus CICC 6075 may be a good candidate probiotic for preventing obesity.

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.

Depression is a prevalent mental health disorder, and its incidence has increased further because of the COVID-19 pandemic. The gut microbiome has been suggested as a potential target for mental health treatment because of the bidirectional communication system between the brain and gastrointestinal tract, known as the gut-brain axis. We aimed to investigate the relationship between the human gut microbiome and depression screening by analyzing the abundance and types of microbiomes among individuals living in Japan, where mental health awareness and support may differ from those in other countries owing to cultural factors. We used a data-driven approach to evaluate the gut microbiome of participants who underwent commercial gut microbiota testing services and completed a questionnaire survey that included a test for scoring depressive tendencies. Our data analysis results indicated that no significant differences in gut microbiome composition were found among the groups based on their depression screening scores. However, the results also indicated the potential existence of a few differentially abundant bacterial taxa. Specifically, the detected bacterial changes in abundance suggest that the Bifidobacteriaceae, Streptococcaceae, and Veillonellaceae families are candidates for differentially abundant bacteria. Our findings should contribute to the growing body of research on the relationship between gut microbiome and mental health, highlighting the potential of microbiome-based interventions for depression treatment. The limitations of this study include the lack of clear medical information on the participants' diagnoses. Future research could benefit from a larger sample size and more detailed clinical information.

Nukadoko, a fermented rice bran bed for pickling vegetables called nukazuke, has a complex microbiota. Within it, deep interactions between the microbiota of the pickled vegetables and nukadoko characterize and control the qualities of both products. To address this notion, we monitored the changes in the microbiota of nukadoko and nukazuke while pickling different vegetables. Raw or roasted rice bran was mixed with salted water and fermented at 24℃ for 40 days, following which different species of vegetable, Cucumis sativus var. sativus, Brassica oleracea var. capitata, or Raphanus sativus var. hortensis, were pickled. The microbial composition of the washing solution of fresh vegetables, as well as that of the nukadoko and nukazuke for each vegetable, was analyzed by amplicon sequencing of 16S rRNA genes. Although the microbiota of nukadoko varied depending on the species of pickled vegetables, no transcolonization of any species of bacteria from fresh vegetables to nukadoko was observed. However, some lactic acid bacterium (LAB) species eventually dominated the microbiota of both nukazuke and matured nukadoko, although they were not detected in either the fresh vegetables or rice bran. Particularly, Lactiplantibacillus plantarum was dominant among all pairs of pickled vegetables and matured nukadoko, whereas the transcolonization of some other LAB species was observed in a pickled vegetable-specific manner. Staphylococcus xylosus was observed to some extent in each nukadoko, yet it was not detected in any nukazuke. Overall, a LAB-dominant microbiota was established in both nukadoko and nukazuke in an underlying process that was different but partly common among vegetables.

Emerging research indicates the potential involvement of gut bacteria in the etiology of Graves’ Disease (GD). However, the evidence regarding this matter is still conflicting. The primary objective of this investigation was to examine the correlation between gut microbiota and GD. A comprehensive search was conducted of the Cochrane Library, Scopus, Europe PMC, and Medline databases up until August 1, 2023, utilizing a combination of relevant keywords. This review incorporates literature that examined the composition of gut microbiota in patients with GD. We employed random-effect models to analyze the standardized mean difference (SMD) and present the outcomes together with their corresponding 95% confidence intervals (CIs). A total of ten studies were incorporated. The results of our meta-analysis indicated that patients with GD have a reduced alpha diversity of gut microbiota as evidence by a significant reduction of Chao1 (std. mean difference –0.58; 95% CI –0.90, –0.26, p=0.0004; I²=61%), ACE (std. mean difference –0.64; 95% CI –1.09, –0.18, p=0.006; I²=77%), and Shannon index (std. mean difference –0.71; 95% CI –1.25, –0.17, p=0.01; I²=90%) when compared with healthy controls. At the phylum level, the abundance of Firmicutes was reduced in GD patients, while that of Bacteroidetes was increased. This study suggests a notable decrease in the richness and variety of gut microbiota among people diagnosed with GD in comparison with healthy controls.

Intestinal homeostasis and integrity are important factors for maintaining host health. This study established intestinal epithelial cell lines and organoids from the same swine jejunal crypts to develop seamless swine intestinal in vitro evaluation systems. The study evaluated the proliferative capacity and tight junction formation of the epithelial cell line and characterized the cell differentiation potential of the intestinal organoids. The evaluation systems were subsequently exposed to the TLR3 agonist poly(I:C) to simulate viral infections and assess the antiviral responses. The results demonstrated no differences in the response to type I interferons. There were, however, significant differences in the expression of interferon-stimulated genes. This study collectively introduced a flexible evaluation system using cell lines and organoids and revealed notable differences in the expression of interferon-stimulated genes, highlighting the complexity of the immune responses in these in vitro systems and the importance of intestinal heterogeneity in assessing viral responses.

Probiotics such as bifidobacteria have been given to low-birth-weight neonates (LBWNs) at risk for a disrupted gut microbiota leading to the development of serious diseases such necrotizing enterocolitis. Recently prebiotics such as lactulose are used together with bifidobacteria as synbiotics. However, faster and more powerful bifidobacteria growth is desired for better LBWN outcomes. The prebiotic 1-kestose has a higher selective growth-promoting effect on bifidobacteria and lactic acid bacteria in vitro among several oligosaccharides. Twenty-six premature neonates (less than 2,000 g) admitted to a neonatal intensive care unit (NICU) were randomly assigned to receive Bifidobacterium breve M16-V with either 1-kestose or lactulose once a day for four weeks from birth. A 16S rRNA gene analysis revealed similar increases in alpha-diversity from 7 to 28 days in both groups. The most dominant genus on both days was Bifidobacterium in both groups, with no significant difference between the two groups. Quantitative PCR analysis revealed that the number of S. aureus tended to be lower in the 1-kestose group than in the lactulose group at 28 days. The number of E. coli was higher in the 1-kestose group at 7 days. The copy number of total bacteria in the 1-kestose group was significantly higher than that in the lactulose group at 3 time points, 7, 14, and 28 days. No severe adverse events occurred in either group during the study period. l-Ketose may offer an alternative option to lactulose as a prebiotic to promote the development of gut microbiota in LBWNs.

Pulmonary fibrosis is an end-stage respiratory disease characterized by fibroblast proliferation and accumulation of extracellular matrix and collagen, which is accompanied by inflammatory damage. The disease is mainly based on pulmonary dysfunction and respiratory failure, the incidence of it is increasing year by year, and the current treatment methods for it are limited. In recent years, it has been found that gut microbes play a crucial role in the pathogenesis and development of pulmonary fibrosis. The microecological disturbance caused by changes in the composition of the intestinal flora can affect the course of pulmonary fibrosis. The regulatory network or information exchange system for gut-lung crosstalk is called the “gut-lung axis”. This review focuses on the frontier research on entero-pulmonary regulation in pulmonary fibrosis and on intervention strategies for changing the gut microbiota to improve pulmonary fibrosis, including fecal microbiota transplantation, traditional Chinese medicine interventions, and supplementation with probiotics. In addition, the present problems in this field are also raised in order to provide strong theoretical and strategic support for the future exploration of regulatory mechanisms and therapeutic drug development. This paper reviews the interaction of the intestinal flora with pulmonary fibrosis, introduces the research progress for improving pulmonary fibrosis through interventions targeted at the intestinal flora, and provides new ideas for the treatment of pulmonary fibrosis.