Breathing is something we take for granted. It’s automatic. We don’t need to think about it. But for people with pulmonary fibrosis, breathing is something that is always on their minds.

Pulmonary fibrosis (PF) is a disease where the tissue in your lungs becomes thick and stiff, even scarred, making it difficult to breathe. It can be a frightening experience; and it doesn’t just affect your lungs.

Because your lungs don’t work properly they aren’t able to move as much oxygen as you need into your bloodstream, and that can have an impact on all your other organs, such as your brain and heart. There are some treatments but no cures, in large part because we didn’t know the cause of the disease. Many patients with PF live only 3-5 years after diagnosis.

Now a new CIRM-funded study from researchers at Cedars-Sinai has uncovered clues as to the cause of the disease, and that in turn could pave the way to new treatments.

The study, published in the journal Nature, found that a class of stem cells in the lung, called AEC2s, are responsible for helping repair damage caused by things such as pollution or infection. People who have PF have far fewer of these AEC2 cells, and those cells also had a much lower concentration of a chemical substance called hyaluronan, which is essential for repair damaged tissue.

They tested this theory with laboratory mice and found that by removing hyaluronan the mice developed thick scarring in their lungs.

In a news release from Cedars-Sinai Carol Liang, the study’s first author, said knowing the cause of the problem may help identify potential solutions:

“These findings are the first published evidence that idiopathic pulmonary fibrosis is primarily a disease of AEC2 stem cell failure. In further studies, we will explore how the loss of hyaluronan promotes fibrosis and how it might be restored to cell surfaces. These endeavors could lead to new therapeutic approaches.”

Knowing that a problem with AEC2 cells causes PF means the researchers can now start testing different medications to see which ones might help boost production of replacement AEC2 cells, or help protect those still functioning.