Gut Microbiome and Metabolomics Profiles of Allergic and Non-Allergic Childhood Asthma.

Purpose: This study aimed to investigate the characteristics of gut bacteria and the derived metabolites among allergic asthmatic children, non-allergic asthmatic children and healthy children without asthma. Methods: Fecal samples were collected from 57 participants, including 20 healthy children, 27 allergic asthmatic children, and 10 non-allergic asthmatic children. 16S rRNA gene sequencing was conducted for analyzing gut bacterial compositions and untargeted metabolomics was used to analyze the alterations of gut microbe-derived metabolites. The associations between gut bacterial compositions and metabolites were analyzed by the method of Spearman correlation. Results: The results showed that the compositions and metabolites of gut microbiome were altered both in allergic and non-allergic asthmatics compared with healthy controls. Chao1 (p = 0.025) index reflected a higher bacterial richness and Simpson (p = 0.024) index showed a lower diversity in asthma group. PERMANOVA analysis showed significant differences among the three groups based on unweighted UniFrac distance (p = 0.001). Both allergic and non-allergic asthmatics showed a higher relative abundance of Proteobacteria and a lower relative abundance of genera from Clostridia. More bacteria were altered in non-allergic asthmatics compared with allergic asthmatics. Metabolomics analysis identified that 42 metabolites were significantly associated with allergic asthma, and 58 metabolites were significantly associated with non-allergic asthma (multiple linear regression, p < 0.05). Histamine was 4 folds up-regulated only in the non-allergic asthma group. The relative abundance of Candidatus Accumulib was significantly correlated with the upregulation of histamine. The relative abundance of genera from Clostridia was significantly correlated with the downregulation of lipid and tryptophan metabolism. Conclusion: The altered gut microbes was associated with the mechanism of asthma attack through metabolites in allergic and non-allergic asthma group, respectively. The result suggested that gut microbiome had an impact on the development of both allergic and non-allergic asthma. The distinct gut microbiome and microbiome-derived metabolites in non-allergic asthma children suggested that gut microbiome might play a critical role in modulation of asthma phenotype.

The Impact of Air Pollution on Intestinal Microbiome of Asthmatic Children: A Panel Study.

Air pollution could impact on the alteration of intestinal microbiome. Maturation of intestinal microbiome in early life played an important role in the development of allergic diseases, including asthma. Recent studies presented an increase in the evidence of association between the shift of gut microbiota and asthma. This article is aimed at exploring whether the alteration in the intestinal microbiome triggered by a short wave of air pollution could influence the colonization of bacteria that have been related to the immunological mechanisms of the asthma attack. The impact of air pollution on intestinal microbiome was assessed by longitudinal comparison. Fecal samples were collected twice for twenty-one children in clean and smog days, respectively, including eleven asthmatic children and ten healthy children. Intestinal bacteria were discriminated by using the method of 16S rRNA gene sequence. The results showed that the composition of intestinal microbiome changed between clean and smog days among all children (PERMANOVA, P = 0.03). During smog days, Bifidobacteriaceae, Erysipelotrichaceae, and Clostridium sensu stricto 1 decreased, and Streptococcaceae, Porphyromonadaceae, Rikenellaceae, Bacteroidales S24-7 group, and Bacteroides increased in asthmatic children (Wilcoxon test, P < 0.05), while Fusicatenibacter decreased and Rikenellaceae and Terrisporobacter increased in healthy children (Wilcoxon test, P < 0.05). After controlling for food consumption, the relative abundance of some bacteria belonging to Firmicutes negatively associated with concentration of PM2.5, PM10, NO2, and SO2 (multiple linear regression, P < 0.05). This study demonstrated that short wave of air pollution had an impact on the intestinal microbiome of asthmatic children. Intestinal bacteria, which have been related to immunological mechanisms of asthma attack, were also found to be associated with air pollution. This finding suggested that a short wave of air pollution may trigger asthma by impacting on intestinal bacteria.

The association between short-term exposure to extremely high level of ambient fine particulate matter and blood pressure: a panel study in Beijing, China.

High blood pressure (BP) is known as the main determinant of high cerebrovascular disease levels in China. Many studies discovered the associations between short-term exposure to PM2.5 and BP, while most of those focused on low or medium PM2.5 concentration. The aim of this study was to reveal the association between extremely high level ambient PM2.5 exposure and BP. We conducted a repeated-measures panel study in Beijing, China, during December 1, 2016 to December 28, 2016. BP was monitored daily for all 133 participants. Daily concentration of PM2.5 was obtained from local monitoring sites. A linear mixed-effect model combined with the distributed lag non-linear model was used to evaluate the associations between PM2.5 and daily variations in BP. This study showed short-term exposure to PM2.5 that was significantly associated with increased DBP (on lags of 0-8 days, Beta = 0.12, 95% confidence interval 0.04, 0.20). The single day effect of PM2.5 on DBP had a 2-day lag, and the cumulative effect lags 5 days. The effects of PM2.5 on SBP and DBP on hypertensive adults were significant. The cumulative effect of PM2.5 on SBP and DBP had 2 rapidly increasing periods in hypertensive adults: lags of 0-2 days and lags of 0-7 days to lags of 0-11 days. Our study revealed that short-term exposure in the extreme high level of ambient PM2.5 may increase BP among adults. Hypertensive adults may more sensitive than normotensive adults. The periodic high concentration of ambient PM2.5 might magnify the effect of PM2.5 on BP increase.