Altered gut microbiome compositions are associated with the severity of asthma

Abstract

Background: Despite substantial evidence on the contribution of the diversity of the gut microbiome to the pathogenesis of asthma and allergic diseases, little is known about their relationship with asthma severity and/or clinical phenotypes. We analyzed the difference in composition of the gut microbiome between subjects with asthma and healthy subjects and explored its role in the development of asthma. Methods: Fecal samples from 15 subjects with severe asthma (SA), 14 with non-severe asthma (NSA), and 15 healthy subjects were assessed by 16S ribosomal RNA gene sequencing methods to identify the gut bacterial composition. Results: Compared with those in the NSA group, patients in the SA group had a higher dose of inhaled corticosteroids, and there were more atopic subjects (60% vs. 35.7%, respectively). No significant differences were found at the phylum level either in operational taxonomic unit numbers or in diversity scores among the SA, NSA, and healthy groups. However, at the family level, the relative abundance of Acidaminococcaceae in the SA group was remarkedly lower than that in the group with healthy subjects (P<0.05). Furthermore, Veillonellaceae and Prevotellaceae were significantly more common in samples from the SA group than in those from the NSA group (P<0.05). In the SA group, positive correlations were observed between the relative abundance of Veillonellaceae and mid-expiratory flow 25% (MEF25%) predicted (r=0.538, P=0.047), as well as between the relative abundance of Acidaminococcaceae and body mass index (r=0642, P=0.010). Principal component analysis suggested that the relative abundances of Acidaminococcaceae and Prevotellaceae were associated with severe asthma. Moreover, we found that class Betaproteobacteria, order Burkholderiales, and family Alcaligenaceae were significantly different among the groups defined by serum immunoglobulin E (IgE) levels. Conclusions: Our findings suggest that altered gut microbiome compositions are involved in the severity of asthma and that there are specific bacteria related to different asthma phenotypes in terms of serum IgE levels.

Vulnerability to acid reflux of the airway epithelium in severe asthma

“…While our ex vivo transcriptome analysis of bronchial brushings did not completely match our in vitro results from ALI cultures, this may be because the in vitro model represents a single acute stress event caused by exposure to MCP-PAB conditions which do not fully reflect the complexity of gastric juice, whereas the clinical condition of GORD is characterized by repeated exposures to various components of gastric juice. In addition, severe asthma patients with GORD treated with PPI may present a dysregulated aerodigestive microbiome, with a potential role in severe asthma (36,37). Nonetheless, we were able to identify 15 dysregulated genes in brushings from severe asthmatics with GORD among the 37 top dysregulated genes in MCP-PAB-exposed ALI cultures, with the extent of dysregulation being higher in cultures from severe asthmatics than in those from healthy controls.…”

The Changes in Bacterial Microbiome Associated with Immune Disorder in Allergic Respiratory Disease

“…A pooled analysis of multiple studies confirms that there are various bacterial changes in the gut of patients with allergic respiratory disease [ 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ]. For this review, we mainly considered changes in gut bacteria in patients with AR and asthma, as only a few 16srRNA gene sequence analyses have been performed on gut bacteria of patients with CRS ( Figures S1B and S2 ), and these findings in CRS show increased levels of Enterobacter and a decline in Bifidobacterium [ 31 ].…”

“…In addition, Adlercreutzia and Eggerthella of the Eggerthellaceae family have been found at high levels in patients with AR and asthma, respectively [ 51 , 52 , 55 ]. Furthermore, increased levels of the genera and family from Fusobacteria have been reported in both diseases [ 49 , 57 ]. Overall, when we consider changes in gut bacterial composition in patients with AR and asthma, we find a complex and inconsistent picture.…”

Bacterial and Fungal Adaptations in Cecum and Distal Colon of Piglets Fed With Dairy-Based Milk Formula in Comparison With Human Milk

“…Burkholderiales are gram-negative bacteria and previously were shown to increase with consumption of western style diet for 12 weeks ( Volynets et al, 2017 ). In addition, the same bacteria were higher in low-IgE asthma subjects relative to high-IgE asthma group ( Wang et al, 2021 ). We speculate that the formula feeding–associated changes likely impact health outcomes, and this requires future translational and mechanistic studies to fully determine the impact of these taxonomic changes on the gut and immune system.…”