Excessive airway nerves tied to more severe asthma symptoms, study finds

September 5, 2018, Oregon Health & Science University
Researchers Matthew Drake, M.D. (left), and lab manager Emily Blum use a confocal microscope to generate three-dimensional imagery of airway nerves. Their research demonstrated that inflammatory cells can alter nerve structure in the lungs to cause asthma. Credit: Kristyna Wentz-Graff/OHSU

A new study implicates remodeling of nerves in the airways as a key contributor to heightened sensitivity and airway constriction in patients with asthma.

The study published today in the journal Science Translational Medicine.

The results provide new insight into a little-understood factor in the development of asthma, a condition that affects about 235 million people worldwide. The study is the first to demonstrate that inflammatory cells can alter structure in the lungs to cause disease.

Airway nerves sense inhaled particles, such as pollen and smoke, in the environment and help regulate constriction. In asthma, these nerves become more sensitive, causing patients to develop symptoms of wheezing and cough. Although previous research had shown that two-thirds of patients with asthma have an overabundance of a type of immune cell, called , the effects of eosinophils on airway nerves were not fully understood.

To study airway nerves in asthma, researchers used OHSU's state-of-the-art confocal microscopes to generate three-dimensional imagery capturing a complete picture of airway nerves and their interactions with eosinophils.

"Picture the branches of trees in a forest," said lead author Matthew Drake, M.D., assistant professor of medicine (pulmonary and ) in the OHSU School of Medicine in Portland, Oregon. "In previous studies, researchers could only visualize small sections of the branches, which meant you could never see the whole tree or how multiple trees fit together. With our new method, you can see both the forest and the trees."

A quantitative 3D model of airway sensory nerves (green) from a patient with moderate persistent asthma. Credit: M.G. Drake et al., Science Translational Medicine (2018)

Using this new 3-D method, Drake's team studied the length of nerves and how often they branch in the airways of healthy patients and in with asthma. They found that in asthma, airway nerves are denser.

"In essence, the trees are growing more branches," Drake said. "As a result of those changes, nerves are more easily irritated, which leads to exaggerated responses that constrict the airway."

The research also showed that having more eosinophils increased the likelihood of having denser nerves and that increased nerves connected with more severe asthma symptoms.

"Changes in nerve structure are clearly tied to worse lung function in asthma," Drake said.

However, future studies are needed to determine whether these changes are preventable, or if this process is reversible once it is established, either by treating with currently available drugs or by developing new medications, Drake said.

Explore further: Why antacids—not your inhaler—may be the key to treating your asthma

More information: Matthew G. Drake et al, Eosinophils increase airway sensory nerve density in mice and in human asthma, Science Translational Medicine (2018). DOI: 10.1126/scitranslmed.aar8477

Related Stories

Why antacids—not your inhaler—may be the key to treating your asthma

June 5, 2018
Asthma is a relatively common lung problem, usually caused by allergies, heavy exercise or chemical exposure in the workplace. But Dr. Alexei Gonzalez Estrada, a Mayo Clinic allergy and immunology specialist, says most people ...

Animal study reveals a skin itch receptor contributes to airway constriction

March 9, 2018
Working with mice, Johns Hopkins researchers report they have found previously known skin itch receptors in the airways that appear to contribute to bronchoconstriction and airway hypersensitivity, hallmarks of asthma and ...

Small babies and asthma in later life

June 19, 2018
Airway size in rats with a low birth weight is more varied than those born at a normal weight—which Western Australian scientists think may play a role in the development of asthma.

Using lung MRI to see where and why Canadians with asthma have poor disease control

April 4, 2018
Researchers at Western University and McMaster University are developing an innovative lung imaging method that provides a unique window on asthma that is aimed at guiding and personalizing treatment for Canadians with severe, ...

Raising awareness about asthma is critical, says expert

May 15, 2018
Millions of people in the United States, regardless of age, gender, race and ethnicity, are impacted by asthma, and the number of asthma sufferers is only projected to grow. To raise awareness about this disease, May is recognized ...

Researchers ID microbiome genes tied to asthma

November 22, 2017
(HealthDay)—Functional genes in the upper airway microbiome may be tied to childhood asthma, according to a study published Nov. 20 in Allergy.

Recommended for you

Study reviews what causes chronic itching and scratching

November 21, 2018
Relentless itch is a feature of many skin disorders, such as eczema and psoriasis, but the cause of this itch—and what drives us to scratch—is somewhat mysterious. A review appearing November 21 in the journal Trends ...

Regulating the immune system's 'regulator'

November 20, 2018
A research team at the Academy of Immunology and Microbiology, within the Institute for Basic Science (IBS) has discovered a possible therapeutic target that pulls the reins of immunity. In Nature Communications, the scientists ...

New immunotherapy improves MS symptoms

November 20, 2018
A world-first clinical trial of a new cellular immunotherapy for multiple sclerosis (MS) has improved symptoms and quality of life for the majority of patients.

Scientists unveil completely human platform for testing age-specific vaccine responses

November 20, 2018
A team of scientists at Boston Children's Hospital has developed the first modeling system for testing age-specific human immune responses to vaccines—outside the body. The practical, cost-effective new platform, using ...

To resolve inflammation, location matters

November 19, 2018
Health conditions that involve inflammation run the gamut, from multiple sclerosis and lupus to arthritis, diabetes, and cancer. While inflammation can serve as a normal response to help the body deal with injury or infection, ...

New insights into how an ordinary stem cell becomes a powerful immune agent

November 19, 2018
How do individual developing cells choose and commit to their "identity"—to become, for example, an immune cell, or a muscle cell, or a neuron?

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.