Integrated Analyses of Gut Microbiome and Host Metabolome in Children With Henoch-Schönlein Purpura

The intestinal microbiota contributes to the development of immune-mediated cardiovascular inflammation and vasculitis in mice

Alterations in the intestinal microbiota contribute to the pathogenesis of various cardiovascular disorders, but how they affect the development of Kawasaki disease (KD), an acute pediatric vasculitis, remains unclear. We report that depleting the gut microbiota reduces the development of cardiovascular inflammation in a murine model mimicking KD vasculitis. The development of cardiovascular lesions was associated with alterations in the intestinal microbiota composition and, notably, a decreased abundance of Akkermansia muciniphila and Faecalibacterium prausnitzii. Oral supplementation with either of these live or pasteurized individual bacteria, or with short-chain fatty acids (SCFAs) produced by them, attenuated cardiovascular inflammation. Treatment with Amuc_1100, the TLR-2 signaling outer membrane protein from A. muciniphila , also decreased the severity of vascular inflammation. This study reveals an underappreciated gut microbiota-cardiovascular inflammation axis in KD vasculitis pathogenesis and identifies specific intestinal commensals that regulate vasculitis in mice by producing metabolites or via extracellular proteins acting on gut barrier function.

IN BRIEF

It remains unclear whether changes in the intestinal microbiota composition are involved in the development of cardiovascular lesions associated with Kawasaki disease (KD), an immune-mediated vasculitis. Jena et al. observe alterations in the intestinal microbiota composition of mice developing vasculitis, characterized by reduced A. muciniphila and F. prausnitzii . Oral supplementation with either of these bacteria, live or pasteurized, or with bacteria-produced short-chain fatty acids (SCFAs) or Amuc_1100, the TLR-2 signaling outer membrane protein of A. muciniphila , was sufficient to alleviate the development of cardiovascular lesions in mice by promoting intestinal barrier function.

HIGHLIGHTS

Absence or depletion of the microbiota decreases the severity of vasculitis in a murine model mimicking KD vasculitis. Supplementation of B. wadsworthia and B. fragilis promotes murine KD vasculitis. Decreased abundances of F. prausnitzii and A. muciniphila are associated with the development of cardiovascular lesions in mice. Supplementation with either live or pasteurized A. muciniphila and F. prausnitzii, or the TLR-2 signaling Amuc_1100, reduces the severity of vasculitis by promoting gut barrier function.

Mendelian randomization reveals association of gut microbiota with Henoch-Schönlein purpura and immune thrombocytopenia

Gut microbiota have been linked to immune thrombocytopenia (ITP) and Henoch-Schönlein purpura (HSP) in recent studies, but a cause-and-effect relationship is unclear. We used Mendelian randomization (MR) to assess causal relationships between gut microbiota and HSP/ITP using summary statistics from the GWAS dataset of the international MiBioGen and FinnGen consortium. The IVW method was used as the main evaluation indicator. MR analysis of 196 intestinal flora and HSP/ITP/sTP phenotypes showed that 12 flora were potentially causally associated with ITP, 6 with HSP, and 9 with sTP. The genes predicted that genus Coprococcus3 (p = 0.0264, OR = 2.05, 95% CI 1.09-3.88)and genus Gordonibacter (p = 0.0073, OR = 1.38; 95% CI 1.09-1.75) were linked to a higher likelihood of developing ITP. Additionally, family Actinomycetaceae (p = 0.02, OR = 0.51, 95% CI 0.28-0.90) and order Actinomycetales (p = 0.0199, OR = 0.50, 95% CI 0.28-0.90) linked to reduced HSP risk. Genus Ruminococcaceae UCG013 (p = 0.0426, OR = 0.44, 95% CI 0.20-0.97) negatively correlated with sTP risk. Our MR analyses offer evidence of a possible cause-and-effect connection between certain gut microbiota species and the likelihood of HSP/ITP.

Characterization of the gut microbiota and fecal and blood metabolomes under various factors in urban children from Northwest China

Introduction

Children have regional dynamics in the gut microbiota development trajectory. Hitherto, the features and influencing factors of the gut microbiota and fecal and plasma metabolites in children from Northwest China remain unclear.

Methods

Shotgun metagenomic sequencing and untargeted metabolomics were performed on 100 healthy volunteers aged 2-12 years.

Results

Age, body mass index (BMI), regular physical exercise (RPE), and delivery mode (DM) significantly affect gut microbiota and metabolites. Lactobacillus, Butyricimonas, Prevotella, Alistipes, and predicted pathway propanoate production were significantly increased with age while Bifidobacterium breve, B. animalis, B. pseudocatenulatum, Streptococcus infantis, and carbohydrate degradation were decreased. Fecal metabolome revealed that the metabolism of caffeine, amino acids, and lipid significantly increased with age while galactose metabolism decreased. Noticeably, BMI was positively associated with pathogens including Erysipelatoclostridium ramosum, Parabacteroides distasonis, Ruminococcus gnavus, and amino acid metabolism but negatively associated with beneficial Akkermansia muciniphila, Alistipes finegoldii, Eubacterium ramulus, and caffeine metabolism. RPE has increased probiotic Faecalibacterium prausnitzii and Anaerostipes hadrus, acetate and lactate production, and major nutrient metabolism in gut and plasma, but decreased pathobiont Bilophila wadsworthia, taurine degradation, and pentose phosphate pathway. Interestingly, DM affects the gut microbiota and metabolites throughout the whole childhood. Bifidobacterium animalis, Lactobacillus mucosae, L. ruminis, primary bile acid, and neomycin biosynthesis were enriched in eutocia, while anti-inflammatory Anaerofustis stercorihominis, Agathobaculum butyriciproducens, Collinsella intestinalis, and pathogenic Streptococcus salivarius, Catabacter hongkongensis, and amino acid metabolism were enriched in Cesarean section children.

Discussion

Our results provided theoretical and data foundation for the gut microbiota and metabolites in preadolescent children's growth and development in Northwest China.

Taxonomic and functional shifts of gut microbiome in immunoglobulin A vasculitis children and their mothers

Objectives

To examine the gut microbiota characteristics in children with immunoglobulin A vasculitis and their interrelationships with the host, while evaluate the vertical inheritance of microbiota in the development and progression of IgA vasculitis.

Methods

This study investigated the gut microbiome of 127 IgA vasculitis mother-child pairs and 62 matched healthy mother-child pairs, and compared the gut microbial composition of different groups. The pathway enrichment analysis evaluated potential gut microbiome-mediated pathways involved in the pathophysiology of IgA vasculitis. The Spearman correlation analysis illustrated the relationships between clinical variables and bacterial biomarkers.

Results

This study identified distinct intestinal microbiome in IgA vasculitis children compared to healthy children, and further pointed out the association in gut microbiota between IgA vasculitis children's and their mother's. The relative abundance of Megamonas and Lactobacillus in IgAV children was positively correlated with that in their mothers. The pathway enrichment analysis found microbial biosynthesis of vitamins and essential amino acids was upregulated in children with IgA vasculitis. Correlation analysis showed bacterial biomarkers were correlated with indicators of blood coagulation.

Conclusion

Children with IgA vasculitis have unique bacterial biomarkers and may affect coagulation function, and their gut microbiome was closely associated with that of their mothers. The observed association in gut microbiota between IgA vasculitis children and their mothers suggested a potential intergenerational influence of the maternal microbiota on the development or progression of IgA vasculitis in children.

The Intestinal Microbiota Composition in Early and Late Stages of Diabetic Kidney Disease

Many studies have suggested that gut microbiota dysbiosis may be one of the pathogenesis factors of diabetes mellitus (DM), while it is not clear whether it is involved in the development of diabetic kidney diseases (DKD). The objective of this study was to determine bacterial taxa biomarkers during the progression of DKD by investigating bacterial compositional changes in early and late DKD. 16S rRNA gene sequencing was performed on fecal samples, including the diabetes mellitus (DM), DNa (early DKD), and DNb (late DKD) groups. Taxonomic annotation of microbial composition was performed. Samples were sequenced on the Illumina NovaSeq platform. At the genus level, we found counts of Fusobacterium, Parabacteroides, and Ruminococcus_gnavus were significantly elevated both in the DNa group (P = 0.0001, 0.0007, and 0.0174, respectively) and the DNb group (P < 0.0001, 0.0012, and 0.0003, respectively) compared with those in the DM group. Only the level of Agathobacter was significantly decreased in the DNa group than the DM group and in the DNb group than the DNa group. Counts of Prevotella_9, Roseburia were significantly decreased in the DNa group compared with those in the DM group (P = 0.001 and 0.006, respectively) and in the DNb group compared with those in the DM group (P < 0.0001 and 0.003, respectively). Levels of Agathobacter, Prevotella_9, Lachnospira, and Roseburia were positively correlated with an estimated glomerular filtration rate (eGFR), but negatively correlated with microalbuminuria (MAU), 24 h urinary protein quantity (24hUP), and serum creatinine (Scr). Moreover, the areas under the curve (AUCs) of Agathobacter and Fusobacteria were 83.33% and 80.77%, respectively, for the DM and DNa cohorts, respectively. Notably, the largest AUC for DNa and DNb cohorts was also that of Agathobacter at 83.60%. Gut microbiota dysbiosis was found in the early and late stages of DKD, especially in the early stage. Agathobacter may be the most promising intestinal bacteria biomarker that can help distinguish different stages of DKD. IMPORTANCE It is not clear as to whether gut microbiota dysbiosis is involved in the progression of DKD. This study may be the first to explore gut microbiota compositional changes in diabetes, early-DKD, and late DKD. We identify different gut microbial characteristics during different stages of DKD. Gut microbiota dysbiosis is found in the early and late stages of DKD. Agathobacter may be the most promising intestinal bacteria biomarker that can help distinguish different stages of DKD, although further studies are warranted to illustrate these mechanisms.

Development and validation of a nomogram to predict recurrence in children with Henoch-Schönlein purpura

BACKGROUND

To screen risk factors for the recurrence in children with Henoch-Schönlein Purpura (HSP) and to develop and validate a nomogram for recurrence in children with HSP.

METHODS

During September 2019 and September 2021, 212 children with HSP were selected in this study. The children were divided into two sets in a proportion of 7:3 using R language, with the first group as the training sets and the second as the internal validation sets. The related variables were analyzed by univariate and multivariate logistic regression analyses, and a nomogram for predicting the recurrence in HSP children was established. The nomogram was evaluated by ROC curve, calibration curve and decision curve, and 1000 times bootstrap resampling method was used to verify the model internally.

RESULTS

Univariate and multivariate regression analyses identified respiratory infection, without preventive medication and diet restriction, age, allergen positive and abnormal urine routine as risk factors for the recurrence in children with HSP. Those risk factors were used to construct a predictive nomogram. The calibration curves revealed excellent accuracy of the predictive nomogram model, internally and externally.

CONCLUSIONS

We constructed and validated a clinical nomogram to predict the recurrence in children with HSP. We confirmed that respiratory tract infection, without preventive medication and diet restriction, age, allergen positive and abnormal urine routine were independent recurrence risk factors. This nomogram had a good performance in clinical decision-making.

Findings on the Relationship Between Intestinal Microbiome and Vasculitis

The microbiome has been implicated in small-, medium-, large-, and variable-vessel vasculitis. Dysbiosis can frequently be found in vasculitis patients with altered microbial diversity and abundance, compared with those with other diseases and healthy controls. Dominant bacteria discovered in different studies vary greatly, but in general, the intestinal microbiome in vasculitis patients tends to contain more pathogenic and less beneficial bacteria. Improvement or resolution of dysbiosis has been observed after treatment in a few longitudinal studies. In addition, some molecular changes in intestinal permeability and immune response have been found in animal models of vasculitis diseases.