Asthma severity may be tied to bacteria living in the upper airway - study
With some six million children under the age of 18 affected by asthma in the US, it remains the leading chronic pediatric disease and the main reason why children miss school days, according to the Asthma and Allergy Foundation of America.
By ILANIT CHERNICKAn inhaler used to treat asthma(photo credit: NIAID/FLICKR)
Is there be a link between asthma severity and the bacteria living in the upper respiratory tract?There could be, according to a new study led by the Washington University School of Medicine in St. Louis that was published on Monday.With some six million children under the age of 18 affected by asthma in the US, it remains the leading chronic pediatric disease and the main reason why children miss school days, according to the Asthma and Allergy Foundation of America.In Israel, the number of those affected by asthma across all ages sits at around 8% of the population.The study, entitled, “The upper-airway microbiota and loss of asthma control among asthmatic children,” looks at the possibility that the airway’s microbiome “could have a causal role in the severity of asthma symptoms,” according to Washington University.“The research paves the way for future studies to discover whether altering the types of bacteria that live in the upper airway could help patients with asthma,” the university added.A microbiome is a complex group of microorganisms that live inside the human body and have a symbiotic relationship with it – the upper respiratory tract has a variety of different microbiomes.Senior author on the study, Prof. Avraham Beigelman, an associate professor of pediatrics at Washington University, explained that “there is an urgent need to develop better asthma therapies for these patients.”Beigelman, who also directs the Kipper Institute of Allergy and Immunology at Schneider Children’s Medical Center at Tel Aviv University, told The Jerusalem Post that they saw it as an opportunity to “try and explain the exacerbation of asthma from an infectious disease standpoint.”“If we can prove that bacteria plays an important role in the activity of asthma then we can plan new interventions, for example if we can prove that bad bacteria causes exacerbation, maybe we will find some way like targeted antibiotics or vaccinations to eliminate that bacteria,” he said. “It’s a very important and relevant question.”He said that although “our study can’t prove causation, it raises intriguing questions that we plan to pursue.”“If we somehow supplement such patients with what appear to be good bacteria, will they do better? We are interested in studying whether we can deliberately alter the airway microbiome to reduce the risk of worsening asthma symptoms,” he explained.What the researchers also discovered was that children who had early warning signs that their asthma was going to flare up “were more likely to have bacteria associated with disease,” which include Staphylococcus, Streptococcus and Moraxella bacterial groups, living in their upper airways.“In contrast, airway microbes dominated by Corynebacterium and Dolosigranulum bacteria were associated with periods of good health, when asthma was well-controlled,” the study found.The researchers also highlighted that children whose airway microbial communities switched from being dominated by Corynebacterium and Dolosigranulum bacteria to being dominated by Moraxella bacteria were at the highest risk of worsening asthma symptoms in comparison to those “whose microbial communities made any other kind of shift.”According to Dr Yanjiao Zhou, who conducted postdoctoral microbiome and bioinformatics research at Washington University, the data revealed “a rapid change of the airway microbiome in the children who transitioned from respiratory health to disease.”Zhou highlighted in a press statement that it was “intriguing to find that the microbiome changing pattern could play an important role in asthma exacerbation. We are planning future studies to explore this possibility.”Beigelman made it clear that they are very cautious because its an association study. He highlighted that “bad bacteria that is associated with a bad outcome doesn’t prove yet that the bad bacteria caused the bad outcome.”He said that they plan to conduct a study in mice “with carefully controlled airway microbiomes to see if the researchers can uncover a causal role for bacteria in asthma severity.”This could also allow the researchers to “test different interventions that might deliberately alter the upper airway bacteria in a way that could be protective.”The study was study was done in conjunction with a clinical trial involving 214 children aged between five and 11, who had mild to moderate asthma. The trial, called Step Up Yellow Zone Inhaled Corticosteroids to Prevent Exacerbations, was conducted as part of AsthmaNet, a national network of medical centers conducting asthma research funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health.During that trial, nasal blow samples were collected from the children to study their upper airway microbiomes. Samples were collected at the beginning of the trial, when all of the participants had controlled asthma, as well as at the first early signs that asthma control was slipping.Beigelman added that it took about five years to plan and conduct the research.The study was published in the December 16 edition of Nature Communications.
