Severe Asthma: Preventing & Treating Airway Remodeling
So, in a previous post, I described “What Airway Remodeling Is." In this post, I would like to discuss ways of preventing or treating severe asthma caused by airway remodeling. Here’s what to know.
What is airway remodeling?
About 5-10% of asthmatics have severe asthma. Airway remodeling is responsible for the diagnosis of severe asthma in some (maybe all) of these patients.Remodeling is when the airway walls of asthmatics become abnormally thick and hypersensitive to asthma triggers. If I seem vague in my definition here it’s because researchers are still on the cutting edge of learning about this.
What is the history of airway remodeling?
Asthma guidelines were first created during the late 1980s and early 1990s. The discovery of airway remodeling, and the belief that it might be caused by more than one severe asthma episodes in a short period of time, or prolonged uncontrolled asthma over a long period of time, was what prompted one of the first changes to these guidelines.1
During the mid-1990s, the experts changed these guidelines to recommend that most asthmatics be prescribed a daily regimen of inhaled corticosteroids (ICS) to reduce this airway inflammation and control asthma. This seemed to benefit most asthmatics. It also seemed to prevent the progression of airway remodeling in most asthmatics. 1
However, about 5-10% continued to have uncontrolled asthma despite treatment with the highest doses of ICS. This was how the asthma phenotype Severe Asthma came to be recognized. This is what prompted all this research on airway remodeling.
What is the treatment for airway remodeling?
There is no specific or universally agreed upon treatment for airway remodeling at the present time. However, there are a couple current options on the market that might prove helpful, one surgical and one medicinal.
This is a procedure where a thin tube is inserted through your nose or mouth into your lungs. This would be done in a surgical setting, so you would be put to sleep during the procedure. Bronchial smooth muscles are then burned away. This would work to make airway walls less thick. It would also make it so these smooth muscles could no longer constrict and narrow airways. It seems to be a very promising treatment for severe asthma. If you are interested in learning more about it, our editors wrote about the procedure in their post, "Bronchial Thermoplasty".
Some studies show that biologics may prove useful. One example is the anti-IgE monoclonal antibody called Xolair. Some studies have revealed that it may improve asthma control in those with severe allergic asthma long after the medicine is stopped. Researchers seem to think that this may be because these IgE blockers may reverse, at least partially, any airway remodeling that may have occurred. This may be because IgE, which plays a key role in allergic inflammation, may also play a role in airway remodeling.2,3
What about a new line of asthma treatments?
There are some areas that researchers think might result in future treatment options.
While there have been various theories explaining this remodeling, one theory is that it’s caused by bronchospasm. Certain proteins are released when airway smooth muscles spasm that might contribute to airway remodeling. So, some researchers seem to think that finding a new line of treatment to reverse, at least partially, or at least “stabilize” remodeled airways when it’s diagnosed, might improve asthma control in those diagnosed with severe asthma.4
Another avenue for treatment might be medicines to block the effects of a cytokine (protein) called TGF-β or another substance called spasmogen methacholine. These are both thought to be secreted by bronchial smooth muscles when they constrict (during bronchospasm). These are thought to cause remodeling.4,5
At the present time, there is no such medicine.
Will there be an eventual new-line treatment for airway remodeling?
There is some airway remodeling that might be permanent. However, there is always the hope that, as airway remodeling is further studied, researchers will stumble upon a viable treatment for reversing, if not all, at least some of it. Or, as noted above, at least stabilize it. So, this is always something we can pray for.
What to make of this?
Airway remodeling in asthmatics was first recognized in 1922. It was linked to severe asthma during the 1990s. So, considering the short timespan here, researchers have learned quite a bit about airway remodeling. Hopefully, soon they will discover better strategies for both preventing and treating it.
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