Every chronic disease leaves footprints on the human body. They offer doctors signs of how the disease starts, how it progresses and how we might be able to treat it–both now and in the future. The greatest hopes that both researchers and patients have for disease prevention, symptom alleviation, treatment and cure, lie in this course of study, which is called physiology.
This is true for those studying, treating and living with many chronic diseases, including idiopathic pulmonary fibrosis (IPF). Right now, the only cure we have for idiopathic pulmonary fibrosis is lung transplant. While there are some medications and therapies that can improve lung function and slow IPF progression, there is nothing that stops it in its tracks or reverses the lung damage it causes—not yet, anyway.
What do we know about how pulmonary fibrosis occurs? Let’s explore the physiology of normal lungs and the lungs of an IPF patient.
How Do Lungs Work?
When you inhale, a sheet of muscle called the diaphragm moves downward inside your rib cage. That gives your lungs the room to expand and fill as you breathe in through your nose and mouth.
The lungs are made up of thousands of air-carrying tubes called bronchi and bronchioles that get smaller and smaller until they end at small round sacs, which are called alveoli. Bordering them are capillaries, or tiny blood vessels.
When blood cells reach the capillaries next to the alveoli, they’re deoxygenated. That means that they’ve already traveled through the body to deliver oxygen. Like a race car on a track, they’ve returned to the lungs to refuel. The deoxygenated blood cells exchange carbon dioxide molecules for the oxygen molecules you just inhaled.
This exchange happens across a thin layer of tissue between the alveoli—those tiny air sacs—and the capillaries. The alveoli and the capillaries are only one cell thick, which is why oxygen and carbon dioxide molecules can easily move through it.
What happens next? Re-oxygenated blood flows toward the heart and back out to the rest of the body. The carbon dioxide molecules travel back through the bronchioles and the bronchi until you exhale them.
What Does Idiopathic Pulmonary Fibrosis Do to the Lungs?
Each of the different parts of the lungs must be in top working order for you to be at your best. And when we say “best,” we don’t necessarily mean running a triathlon. We mean walking up a flight of stairs, playing with your kids and enjoying a meal with friends. You know, normal, daily life activities.
Remember those tiny air sacs we mentioned earlier, the alveoli? Pulmonary fibrosis affects the tissue between the alveoli and the capillaries. Somehow—and with idiopathic pulmonary fibrosis, doctors don’t know exactly how it happens—scarring develops in that tissue. And because the alveoli and capillaries are only one cell thick to start with, it doesn’t take much scarring to begin impeding the flow of oxygen and carbon dioxide across that barrier.
What does that mean for an IPF patient? As their pulmonary fibrosis progresses, scarring thickens the tissue surrounding the alveoli. That makes breathing—a simple, automatic action for most people—more and more difficult.
How Do Pulmonary Fibrosis Treatments Work?
Right now, there are only a few approved treatments for IPF and none of them stop the progression of the disease.
Pharmaceuticals can slow the scarring, but they don’t reverse it or stop it entirely. These medications work by slowing down the production of fibrous tissue, which is what makes up scarring.
Certain therapies are used alongside pharmaceutical treatments to improve an IPF patient’s overall quality of life and increase lung function, even as their disease progresses. These therapies target different parts of the respiratory system and the body to boost respiration.
- Breathing exercises, which strengthen your lungs and improve their function
- Oxygen therapy, which sends more oxygen molecules into your lungs and bloodstream
- Systemic enzyme therapy, which can help your body break down fibrous tissue
Some patients with advanced idiopathic pulmonary fibrosis are good candidates for lung transplant, which is the only cure we have for the disease. In fact, IPF is the cause for most lung transplants. While a transplant will stop IPF, however, it isn’t always the answer. Because of the high rate of other health problems in individuals with pulmonary fibrosis and the frequency of complications in transplant patients, issues can still arise.