Airway Microbiome and Host Interact Differently in Children with Severe Asthma
The Mount Sinai study showed that airway microbes interact with inflammatory genes differently in healthy versus asthmatic children.
A collaboration between allergists, pulmonologists, and systems biologists at the Icahn School of Medicine at Mount Sinai has led to major new insights about how the microbiome interacts with the respiratory system in children with asthma. The study, published March 12 in JCI Insight, showed that the airway microbiome interacts with the host differently in children with severe asthma compared to healthy children. It also revealed differences between the microbiome of the upper and lower airways within individual asthmatic children.
“Asthma is affected by genetics and environment, including the microbiome. In trying to understand the dynamics of asthma, examining both together can give you very different insights compared to studying asthma from just one perspective,” said the study’s senior author, Dr. Supinda Bunyavanich, MD, MPH, Professor of Genetics and Genomic Sciences and Pediatrics and at the Icahn School of Medicine at Mount Sinai.
Many studies have attempted to understand the roles of genetics and the microbiome in patients with asthma, but not necessarily how the two interact with one another. Moreover, many studies focus only on the upper airways because of accessibility. In order to obtain samples from the lungs, patients must undergo bronchoscopies — invasive procedures requiring anesthesia.
The Bunyavanich Lab collaborated with Mount Sinai pulmonologists, who perform bronchoscopies as a part of their clinical care of some children with severe persistent asthma, to collect a series of samples from the upper and lower airways from 27 children with severe asthma. For comparison, the researchers also took two samples from the upper airways of 27 healthy children.
Dr. Bunyavanich’s team then used these samples not only to analyze the microbiomes of the upper and lower airways, but also the matching transcriptomes for these sites. Transcriptomics measures the collection of RNA molecules produced by genes, telling scientists about biologic functioning of the human body.
“The unique angle of our study was that we could study not only the presence of various microbiota, but also link these microbiota to what's happening to the person,” said Dr. Bunyavanich.
The group found that among the children with asthma, the upper and lower airways were each home to distinct microbiomes and transcriptomes.
But one of the more surprising findings, according to Dr. Bunyavanich, is that while the nasal passages of both healthy children and those with asthma contained overlapping microbes, some of those microbes seemed to be interacting differently with their hosts. “Similar genes and similar microbiota might be present in children with asthma and those who don't have asthma,” she said. “But an important difference is in how they associate with one another.”
A particular microbe, Corynebacterium, which was present in the nasal passages of both asthmatic and healthy children, seemed to be dampening inflammation more strongly in healthy children compared to children with asthma. The microbe may be playing a protective role in healthy children but doing so less effectively in those with asthma.
“Our study was an important first step to figuring out relationships between host and microbiota in the airways of children with asthma. The next step is to figure out the causal directions for these relationships,” said Dr. Bunyavanich.
About the Mount Sinai Health System
Mount Sinai Health System is one of the largest academic medical systems in the New York metro area, with more than 43,000 employees working across eight hospitals, over 400 outpatient practices, nearly 300 labs, a school of nursing, and a leading school of medicine and graduate education. Mount Sinai advances health for all people, everywhere, by taking on the most complex health care challenges of our time — discovering and applying new scientific learning and knowledge; developing safer, more effective treatments; educating the next generation of medical leaders and innovators; and supporting local communities by delivering high-quality care to all who need it.
Through the integration of its hospitals, labs, and schools, Mount Sinai offers comprehensive health care solutions from birth through geriatrics, leveraging innovative approaches such as artificial intelligence and informatics while keeping patients’ medical and emotional needs at the center of all treatment. The Health System includes approximately 7,300 primary and specialty care physicians; 13 joint-venture outpatient surgery centers throughout the five boroughs of New York City, Westchester, Long Island, and Florida; and more than 30 affiliated community health centers. We are consistently ranked by U.S. News & World Report's Best Hospitals, receiving high "Honor Roll" status, and are highly ranked: No. 1 in Geriatrics and top 20 in Cardiology/Heart Surgery, Diabetes/Endocrinology, Gastroenterology/GI Surgery, Neurology/Neurosurgery, Orthopedics, Pulmonology/Lung Surgery, Rehabilitation, and Urology. New York Eye and Ear Infirmary of Mount Sinai is ranked No. 12 in Ophthalmology. U.S. News & World Report’s “Best Children’s Hospitals” ranks Mount Sinai Kravis Children's Hospital among the country’s best in several pediatric specialties.