You may have heard of airway remodeling somewhere in your search for more answers and information regarding lung disease, specifically asthma and COPD. While there is much information available concerning remodeling, it is also considered by some to be inconclusive because there is still a lot to learn. Any information out there should be presented with the hope that it leads to more discussion, answers and ultimately the desire of patients afflicted with lung disease to better manage themselves and help prevent these sometimes irreversible changes. While more research is needed, there are many things that we do know occur within the lungs due to these disease processes.
When we think of remodeling we think of turning something old, damaged or unsightly into something new and restored. This is not the case with airway remodeling. When someone has asthma or COPD, airway inflammation, lung tissue injury, and abnormal or incomplete repair of the involved tissues occurs. This leads to changes in the structure of the airway walls, which is referred to as airway remodeling. It occurs throughout the bronchial tree, but it is more pronounced in the midsize and small airways.
- Airway Wall Thickening. According to a study published in the Journal of Allergy Vol. 2012 an increase in the thickness of the airway walls is associated with an increase in asthma severity, including near-fatal asthma. Airway wall thickening is a result of the changes that occur during a flare-up, such as altered cells, fibrosis, increased airway smooth muscle and an increase in blood vessels to the airways. In other words, chronic wheezing from either uncontrolled, or poorly controlled asthma, or progressive COPD causes changes in the walls of the airway. Sometimes these changes are reversible, and sometimes they’re not.
- Allergic Airway Inflammation. Most asthma is associated with a person’s genetic likelihood to develop an allergic reaction, so asthma is typically regarded as an allergic disease. Although this allergic-type inflammation is usually considered the main reason for airway remodeling, things such as tobacco smoke and viruses can produce the same type of lung tissue reaction. Allergic and non-allergic forms of asthma don’t look any different as far as the lung changes that occur. The longer the infection and inflammatory response last, the longer it takes for the lung damage to reverse itself (if it reverses at all).
- Physiological Consequences of Airway Remodeling. We’ve already established that airway remodeling is thought to occur soon after the onset of asthma and COPD due to the chronic nature of the diseases. Animal studies have shown that airway remodeling can be prevented, but not fully reversed once initiated. Studies regarding the prevention of airway remodeling and treatments to reverse it are being conducted, and they are providing mixed results. The best course of action at this point is to stay on your medication regimen even when you feel good, get help to keep your asthma or COPD under control, enroll in pulmonary rehab if you have COPD and ask your physician about airway remodeling.
The lung changes that occur asthma and COPD are almost identical, but involve different cells. For more in depth information, read this article.