Neonatal cholestasis disease (NCD) is a complex and easily mis-diagnosed condition. We analyzed microbiota community structure in feces and measured short-chain fatty acids, bile acids (BAs) and liver function of 12 healthy, 13 NCD, and 13 treated infants after diagnosis. Based on 16S rRNA gene amplicon sequencing and gas-chromatographic-mass-spectrometric analysis of secondary BAs, we identified microbial genera and metabolites that associate with abnormal bile secretion. Streptococcus gallolyticus and Parabacteroides distasonis, and Lactobacillus gasseri had higher relative abundance in healthy and NCD infants respectively. Compared to NCD patients, healthy infants had higher LCA, CDCA and GCDCA fecal concentrations. The three microbial species and three secondary bile acids were selected as potential non-invasive combined biomarkers to diagnose NCD. We propose that microbiota-metabolite combined biomarkers could be used for diagnosis of NCD, and this may contribute to improved early clinical diagnosis of NCD in the future.

Background and Aim: The incidence of acute lymphoblastic leukemia (ALL) is highest in childhood malignant tumor in China. The high-dose methotrexate (HDMTX) treatment is very effective in ALL, and it can improve event-free survival rate. However, while executing the anti-tumor effect, it produces highly toxic effects on rapidly dividing cells which are normal. It seems probable that the HDMTX treatment injures intestinal mucosal barrier. The changes of intestinal mucosal barrier can be evaluated through measuring the level of plasma endotoxin and diamine oxidase (DAO). Method: Blood samples were collected from 30 normal children and 30 children with ALL at 1h, 24h, 44h and 68h after HDMTX. The levels of plasma endotoxin and DAO were measured at 1h, 24h, 44h and 68h after HDMTX with spectrophotometry. The levels of endotoxin and DAO were also measured in 4 different courses in 7 children with ALL. Results: The levels of plasma endotoxin and DAO at 1h, 24h, 44h and 68h after HDMTX were higher than in normal children (P<0.01). The levels of plasma endotoxin and DAO at 24h and 44h after HDMTX were both higher than at 1h and 68h (P0.05). There was no significant difference found in the increased levels of endotoxin and DAO at 1h, 24h, 44h and 68h after HDMTX in 4 different courses of 7 children with ALL(P>0.05). Conclusion: By measuring the level of plasma endotoxin and DAO in children with ALL and during HDMTX chemotherapy, the results suggest that there is increased intestinal permeability.

Butyric acid (BA) can potentially enhance the function of the intestinal barrier. However, the mechanisms by which BA protects the intestinal mucosal barrier remain to be elucidated. Given that the Ras homolog gene family, member A (RhoA)/Rho-associated kinase 2 (ROCK2)/Myosin light chain kinase (MLCK) signaling pathway is crucial for maintaining the permeability of the intestinal epithelium, we further investigated whether BA exerts a protective effect on epithelial barrier function by inhibiting this pathway in LPS-induced Caco2 cells. First, we aimed to identify the optimal treatment time and concentration for BA and Lipopolysaccharide (LPS) through a CCK-8 assay. We subsequently measured Trans-epithelial electrical resistance (TEER), FITC-Dextran 4 kDa (FD-4) flux, and the mRNA expression of ZO-1, Occludin, RhoA, ROCK2, and MLCK, along their protein expression levels, and average fluorescence intensity following immunofluorescence staining. We then applied the ROCK2 inhibitor Y-27632 and reevaluated the TEER, FD-4 flux, and mRNA, and protein expression of ZO-1, Occludin, RhoA, ROCK2, and MLCK, as well as their distribution in Caco2 cells. The optimal treatment conditions were determined to be 0.2 mmol/L BA and 5 μg/mL LPS for 24 hours. Compared with LPS treatment alone, BA significantly mitigated the reduction in the TEER, decreased FD-4 flux permeability, increased the mRNA expression of ZO-1 and Occludin, and normalized the distribution of ZO-1 and Occludin in Caco2 cells. Furthermore, BA inhibited the expression of RhoA, ROCK2, and MLCK, and normalized their localization within Caco2 cells. Following treatment with Y-27632, the epithelial barrier function, along with the mRNA and protein expression and distribution of ZO-1 and Occludin were further normalized upon inhibition of the pathway. These findings contribute to a deeper understanding of the potential mechanisms through which BA attenuates LPS-induced impairment of the intestinal epithelial barrier.

Objectives: Immunoglobulin A vasculitis (IgAV), previously known as Henoch–Schönlein purpura, is the most common vasculitis that has a classical skin manifestation of palpable purpuric rash. Factors pertinent to IgAV remain inadequately understood. Here, we aimed to examine the gut microbiome shifts associated with IgAV and its recovery.Methods: Stool samples were collected from 10 children with IgAV (6–14 years old) before and after a multi‐drug therapy, along with 9 age‐matched healthy children. The samples were subjected to metagenomic analyses to investigate the taxonomic and functional shifts of the gut microbiome.Results: The analyses revealed that compared with healthy controls, treatment‐naïve patients exhibited substantial taxonomic and functional alterations of gut microbiota, including 104 IgAV‐depleted species and 7 IgAV‐elevated species (FDR < 0.05). After treatment, the IgAV patients displayed a partial restoration of the microbiota shifts, as the relative abundances of some biomarkers (e.g. 9 genera and 22 species) became comparable (FDR > 0.1) between the patients and healthy controls. The treatment‐responsive features included Weissella, Faecalibacterium prausnitzii and Bifidobacterium pseudocatenulatum and three components of a putative glutamine transport system. Importantly, gram‐positive bacteria accounted for over 85% of the numbers and total relative abundance of the species that were associated with IgAV and responsive to the treatment. In addition, of the 122 IgAV‐depleted bacterial genes, 82 were mainly contributed by gram‐positive bacteria and 12 by gram‐negative bacteria.Conclusions: Gram‐positive bacteria are the main drivers underlying the gut microbiome shifts of IgAV, which may assist rational management of the disease.

Rhizoctonia solani AG-1 IA is one of the most important fungal pathogens that causes severe yield losses in rice-growing regions worldwide. Catechol (1, 2-benzenediol) is a natural catecholamine which can induce melanization of fungi and contribute to enhanced virulence and fungal resistance to diverse environments. In this study, the effects of catechol on growth, activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), glutathione S-transferase (GSH-ST), glutathione peroxidase (GSH-PX) and glutathione reductase (GR), as well as expression of melanin biosynthesis genes in R. solani AG-1 IA, were evaluated by culturing the fungus in catechol-containing nutrient media. The results showed that the activities of CAT, POD, SOD, GSH-ST, GSH-PX and GR were decreased in the presence of 12.5–50 μg mL⁻¹ catechol, while GSH-PX activity was significantly increased (by 310%) in the presence of 50 µg mL⁻¹ catechol. The growth rates of R. solani AG-1 IA on potato dextrose agar (PDA) containing catechol were significantly decreased, whereas the pathogenicity to rice of R. solani AG-1 IA cultured on PDA containing different concentrations of catechol was enhanced when compared with the catechol-free control. Quantitative RT-PCR results showed that the expression of four melanin biosynthesis genes, i.e. protein tyrosine phosphatase (Ptp), chorismate mutase (Cm), peroxidase (Per) and phenol hydroxylase (Ph), was significantly down-regulated in R. solani AG-1 IA cultured in catechol-containing PDB at 100 µg mL⁻¹. These results suggest that catechol was utilized by the fungus to synthesize melanin, and it could also induce the activities of antioxidant enzymes and melanization in R. solani AG-1 IA. Our results provide strong evidence to support the view that melanin contributes to virulence directly through fungal antioxidant defence systems in which melanization is induced by oxidative stress.

Background: Previous research has indicated that chenodeoxycholic acid (CDCA) plays a significant role in intestinal motility and is implicated in some gastrointestinal (GI) disorders. However, the impact of CDCA on defecation patterns in infants, particularly those who are breastfed, remains unclear. This study explored the relationship between CDCA and defecation frequency in breastfed infants, focusing on the underlying mechanisms. Methods: We measured CDCA levels in stool samples of infants with varying defecation frequencies using metabolomics, along with studies to explore the impact of CDCA on murine colonic transit and with in vitro cellular studies to elucidate the underlying physiological mechanisms. Results: In our murine model, CDCA treatment increased GI transit distance, enhanced fecal water content, and reduced transit time, without causing significant colonic damage. Additionally, CDCA treatment enhanced 5-hydroxytryptamine (5-HT) secretion and upregulated signaling molecules such as tryptophan hydroxylase 1 (Tph1), G protein-coupled bile acid receptor 1 (TGR5), and transient receptor potential ankyrin 1 (TRPA1). Selective inhibition of these pathways suppressed 5-HT secretion and normalized intestinal motility parameters, confirming their mechanistic role. Moreover, CDCA treatment of rat insulinoma-derived RIN-14B cells also resulted in increased 5-HT secretion. Conclusions: These findings reveal that CDCA significantly correlates with defecation frequency in breastfed infants and likely influences intestinal motility through the TGR5/TRPA1-5-HT signaling axis.