Researchers Use Simpler, Safer Method to Obtain Stem Cells for Treating Lung Diseases

A new method of isolating lung stem cells could help speed the development of stem-cell based therapies for lung diseases, including cystic fibrosis, according to a University of North Carolina study.

That method is extracting them with a tube from the mouth to the lung rather than surgery. The team has already used the method in their pulmonary fibrosis research work.

The new study, “Derivation of therapeutic lung spheroid cells from minimally invasive transbronchial pulmonary biopsies,” was published in the journal Respiratory Research.

Doctors can use stem cells to restore injured lungs, but obtaining and maintaining the cells is challenging.

Not only do they need a lot of lung tissue to extract the stem cells, but the way they have obtained the tissue — with surgery — is highly invasive. This has led to high death rates among patients who have had the biopsy surgery.

Still, isolating the cells for stem cell-based therapies is a good way to treat many lung diseases.

Until recently, University of North Carolina Health Care researchers used lung tissue biopsies to obtain stem and support cells that they can cultivate for treatments. They discovered that lung spheroid cells can help regenerate the lungs of mice with interstitial pulmonary fibrosis, or IPF.

The team is now using a relatively non-invasive procedure, called a transbronchial biopsy, to isolate lung spheroid cells while reducing the risks associated with obtaining them by surgery. In this procedure, a lung pneumologist inserts a thin, lighted tube, or bronchoscope,  through a patient’s nose or mouth to collect several pieces of lung tissue.

“This is the first time anyone has generated potentially therapeutic lung stem cells from minimally invasive biopsy specimens,” Dr. Jason Lobo, an assistant professor of medicine at the university, said in a press release.

“We snip tiny, seed-sized samples of airway tissue using a bronchoscope,” said Lobo, a co-lead authoer of the study. “This method involves far less risk to the patient than does a standard, chest-penetrating surgical biopsy of lung tissue.”

They were able to obtain more than 50 million lung spheroid cells from one small piece of isolated tissue. When they injected the cells into mice, they were delighted to find that the cells ended up in the animals’ lungs.

“These cells are from the lung, and so in a sense they’re happiest, so to speak, living and working in the lung,” said the other co-lead author, Dr. Ke Cheng. He is an associate professor in the university’s Departments of Molecular Biomedical Sciences and Biomedical Engineering.

In a second study, published in the journal Stem Cells Translational Medicine, researchers highlighted  lung spheroid cells’ potential to treat cystic fibrosis. Injecting the cells in rats with IPF significantly reduced their lung inflammation and scarring, compared with control animals.

“Also, the treatment was safe and effective, whether the lung spheroid cells were derived from the recipients’ own lungs or from the lungs of an unrelated strain of rats,” Lobo said. “In other words, even if the donated stem cells were foreign, they did not provoke a harmful immune reaction in the recipient animals, as transplanted tissue normally does.”

Scientists have had discussions with the U.S. Food and Drug Administration about clinical trials of lung spheroid cells as a pulmonary fibrosis therapy.

Cells isolated from patients’ own lung tissue would eliminate the risk of the body rejecting the stem cells. Such treatments require a lot cells, however — and doctors might opt to harvest some from healthy volunteers and whole lungs obtained from organ donation networks.

“Our vision is that we will eventually set up a universal cell donor bank,” Cheng said.

The researchers hope that some day their stem cell therapy can be used in other lung diseases, including cystic fibrosis.