Lung Stem Cell Spheroids Could Offer Cheap, Rapid Pulmonary Fibrosis Therapy

In a newly published paper in the Stem Cells Translational Medicine journal entitled Adult Lung Spheroid Cells Contain Progenitor Cells and Mediate Regeneration in Rodents With Bleomycin-Induced Pulmonary Fibrosis, scientists from North Carolina State University discovered a quick and simple method to produce stem cells from adult lung tissues. These findings could be relevant in the treatment of pulmonary fibrosis (PF).

Pulmonary fibrosis is a disease affecting the lungs in which mucus build-up induces inflammation, injury and structural changes of the lungs. In turn, this leads to thickening of the lung walls and reduces oxygen supply in the blood. As a result, patients with PF suffer from perpetual shortness of breath, chest pain, dry coughing, fatigue, and rapid weight loss. It is believed that PF results from the secondary effect of other diseases like autoimmune disorders, and viral/bacterial infections such as tuberculosis, which may induce fibrotic changes in both lungs. However, PF may also be caused by other factors like genetic mutations and environmental pollutants such as metals, cigarette smoking, medications and radiation therapy. Unfortunately, no known cure is available for the damage that occurs in the lung due to pulmonary fibrosis. However, several therapeutic methods are available to manage PF in order to slow down its progression or relieve its symptoms. These therapies include anti-inflammatory medications, oxygen supplementation and surgery in severe cases of PF.

Another emerging therapeutic method that could be promising in treating PF involves stem cell therapy for lung regeneration. In the study performed at North Carolina State University, cells from healthy lung tissue were transferred into a suspension culture then left to self-aggregate to form three-dimensional lung spheroids. The method of utilizing the body’s own cells to treat diseases dates back 30 years, where bone narrow was utilized to treat patients with leukemia. However, the method is generally considered complex, expensive and time consuming. “In current stem cell harvesting, just the process of sorting the stem cells can damage them, wasting not only the cells, but also time and money,” said Ke Cheng, lead author of the project.

With this new method, the research team utilized a three-dimensional cellular structure to grow the stem cells, instead of the old method that involved isolating and sorting individual lung stem cells or genetically converting other categories of cells into lung stem cells. In the new method, layers of supporting cells surround lung stem cells to form a three-dimensional spheroid. This spheroid method has already been utilized to culture cancer cells or embryonic stem cells for research purposes. However, this is the first report illustrating that spheroid environment can be utilized to enrich adult lung stem cells. In addition, no exogenous or transgenic materials are employed and stem cells are 100 percent made from patients’ own genetic material. The method was validated on mice suffering from PF and the results showed a decrease in inflammation and fibrosis that almost matched lungs without PF. More importantly, the cell therapy can be delivered intravenously.

In summary, these findings suggest that lung spheroids and cells taken from healthy lung tissues are excellent sources of regenerative lung cells for therapy of PF. For future plans, the researchers want to harvest the original cells during the biopsy for efficient treatment of humans with PF.