Transplanting patients' own lung cells could 'cure' COPD
Chinese researchers have shown that it is possible to repair damaged lung tissue in patients with chronic obstructive pulmonary disease (COPD) using the patients’ own lung cells, as outlined in a presentation at the European Respiratory Society International Congress.
COPD is a severe respiratory disease that involves progressive damage to lung tissue. The affected tissue cannot be repaired with current treatments; it can only be alleviated with medicines that widen the airways to improve airflow, known as bronchodilators.
To find new treatments for COPD, researchers have been investigating stem cells, which are capable of differentiating into any cell in the body, and progenitor cells, which are descendants of stem cells and can only differentiate into the cells that belong to the same tissue or organ and are normally used by the body to repair and replace damaged tissue. Wei Zuo, a professor at Tongji University and Chief Scientist at Regend Therapeutics, and his colleagues are now investigating whether a type of cell called p63+ progenitor cells might be able to regenerate lung tissue damaged by COPD.
“Stem cell and progenitor cell-based regenerative medicine may be the biggest, if not the only, hope to cure COPD,” Zuo said. “p63+ progenitor cells are known for their ability to regenerate the tissues of the airways, and previously we and other scientists have shown in animal experiments that they can repair the damaged epithelial tissue in the alveoli — the tiny air sacs in the lungs that play a crucial role in the exchange of gases between air breathed in and the blood supply to the lungs.”
In this phase I clinical trial, the researchers set out to investigate the efficacy and safety of taking p63+ progenitor cells from the lungs of 20 COPD patients, using them to grow millions more in the laboratory, and transplanting them back into 17 of the 20 patients’ lungs.
“In our trial, 35% of the patients had severe COPD and 53% had extremely severe COPD,” Zuo said. “Usually, many patients with such severe COPD will die quite quickly if their disease progresses. We used a tiny catheter that contains a brush to collect the progenitor cells from the patients’ own airways. We cloned the cells to create up to a thousand million more, and then we transplanted them back into the patients’ lungs via bronchoscopy in order to repair the damaged lung tissue.”
After 12 weeks, the median (average) diffusing capacity of the lungs (DLCO), which tests how well air is exchanged between the lungs and the bloodstream, increased from 30% before treatment to 39.7%, then increased further to 40.3% at 24 weeks in the treated patients. The median distance covered in a six-minute walk distance test (6MWD) increased from 410 metres before treatment to 447 metres at 24 weeks. The median score in a quality-of-life test (the St George’s Respiratory Questionnaire) reduced by seven points, indicating an improvement. In two patients with mild emphysema, a type of lung damage that is normally permanent and progressive, the treatment repaired the lung damage.
“We found that p63+ progenitor cell transplantation not only improved the lung function of patients with COPD, but also relieved their symptoms, such as shortness of breath, loss of exercise ability and persistent coughing,” Zuo said. “This means that the patients could live a better life, and usually with longer life expectancy.
“If emphysema progresses, it increases the risk of death. In this trial, we found that p63+ progenitor cell transplantation could repair mild emphysema, making the lung damage disappear. However, we cannot repair severe emphysema yet.”
The researchers are planning a phase II trial of the treatment, which will evaluate its efficacy in a larger group of patients. The trial has been approved by China’s National Medical Products Administration (NMPA), the Chinese equivalent of the US Food and Drug Administration (FDA). This means that the treatment is not generally available to COPD patients and their doctors yet.
“However, with more doctors and patients participating in our clinical trial, we may develop the treatment more quickly so that it can benefit patients sooner,” Zuo said. “A similar therapeutic strategy is also being tested in patients with lethal lung fibrotic diseases, including idiopathic pulmonary fibrosis. We are going to test the treatment’s efficacy in larger groups of people with more lung diseases. We hope to develop the treatment for clinical use within about two to three years.”
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