Chronic obstructive pulmonary disease (COPD) is a progressive lung disease that makes it difficult to breathe.
According to the American Lung Association, over 16.4 million people in the United States have been diagnosed with the condition. However, it’s estimated that another 18 million people may have COPD and not know it.
There’s currently no cure for COPD. There are only treatments to improve quality of life and to slow the progression of the disease. However, there’s promising research that suggests stem cells may help treat this type of lung disease.
Stem cells are essential to every organism and share three main characteristics:
- They can renew themselves through cell division.
- Although they’re initially indistinguishable, they can differentiate themselves and take on the properties of several different structures and tissues, as the need arises.
- They can be transplanted into another organism, where they will continue to divide and replicate.
Stem cells may be obtained from four- to five-day-old human embryos called blastocysts. These embryos are usually available from an in vitro fertilization. Some stem cells also exist in various structures of the adult body, including the brain, blood, and skin.
Stem cells are dormant in the adult body and don’t divide unless activated by an event, such as an illness or injury.
However, like embryonic stem cells, they’re able to create tissue for other organs and body structures. They may be used to heal or even regenerate, or regrow, damaged tissue.
The stem cells can be extracted from the body and separated from other cells. They’re then returned to the body, where they can begin to promote healing in the affected area.
COPD causes one or more the following changes in the lungs and airways:
- The air sacs and airways lose their ability to stretch.
- The walls of the air sacs are destroyed.
- The walls of the airways become thickened and inflamed.
- The airways become clogged with mucus.
These changes reduce the amount of air flowing into and out of the lungs, depriving the body of much-needed oxygen and making it increasingly harder to breathe.
Stem cells may benefit people with COPD by:
- reducing inflammation in the airways, which may help prevent further damage
- building new, healthy lung tissue, which can replace any damaged tissue in the lungs
- stimulating the formation of new capillaries, which are small blood vessels, in the lungs; this may lead to improved lung function
The Food and Drug Administration (FDA) hasn’t approved any stem cell treatments for people with COPD, and clinical trials haven’t advanced beyond phase II.
Phase II is where researchers try to learn more about whether a treatment works and its side effects. It’s not until phase III that the treatment in question is compared to other medications used to treat the same condition.
In pre-clinical studies involving animals, a type of stem cell known as the mesenchymal stem cell (MSC) or mesenchymal stromal cell proved to be the most promising. MSCs are connective tissue cells that can transform into various cell types, from bone cells to fat cells.
According to a 2018 literature review, rats and mice who’d undergone transplantation with MSCs typically experienced reduced airspace enlargement and inflammation. Airspace enlargement is a result of COPD, and emphysema in particular, destroying the walls of the lungs’ air sacs.
Clinical trials in humans have yet to reproduce the same positive results that were observed in animals.
- The pre-clinical studies largely used animals with only mild COPD-like disease, while the clinical trials looked at humans with moderate to severe COPD.
- The animals received higher doses of MSCs, relative to their body weights, than the humans. That being said, clinical studies for other conditions suggest that higher doses of stem cells don’t always lead to better results.
- There were inconsistencies in the types of MSCs used. For instance, some studies used frozen or newly thawed stem cells while others used fresh ones.
While there’s no strong evidence yet that stem cell treatment can improve the health of people with COPD, there’s also no strong evidence that stem cell transplantation is unsafe.
Research continues in this direction, with the hope that more carefully designed clinical trials will yield different results.
Researchers envision that stem cells may one day be used to generate new, healthy lungs in people with chronic lung disease. It may take several years of research before stem cell treatment can be attempted in people with COPD.
However, if this treatment comes to fruition, people with COPD may no longer have to go through painful and risky lung transplant surgeries. It may even pave the way for finding a cure for COPD.