In a new study, researchers analyzed discarded tissue from COVID-19 patients who had lung transplants and from patients who died of the disease.
They found that COVID-19 can destroy the fundamental framework of the lungs, meaning the organs simply cannot recover.
This means a patient’s treatment choices become very limited.
The research was conducted by a team at Northwestern Medicine.
Previous research has shown that COVID-19 can cause such severe lung damage that patients require a lung transplant to survive.
This study provides new evidence that COVID-19 can cause permanent damage to the lung in some patients for whom lung transplantation is the only hope for survival.
To date, eight COVID-19 patients have received double-lung transplants at Northwestern Medicine, the most performed at any health system in the world.
The team also discovered unique cells—called KRT17 epithelial cells—in the lung tissue of COVID-19 patients with irreversible damage.
These cells have also been found in patients with end-stage pulmonary fibrosis, a deadly progressive lung disease.
The team says the progenitor cells in the lungs necessary for healing can repopulate wounds of the lung by moving along the basic underlying framework of the lung matrix.
But when the framework is destroyed, the progenitor cells have no place to go and lungs develop large holes that serve to harbor infections.
Lungs attacked by COVID-19 also showed striking similarities to the lungs of patients with a condition called idiopathic pulmonary fibrosis.
In that condition, lung tissue gets thick and stiff, making it difficult for the body to take in oxygen.
As in pulmonary fibrosis, researchers found that COVID-19 led to the recruitment of circulating immune cells called monocytes, which are likely recruited to the lung to kill the virus.
But there was some good news from the report: The researchers also found that it’s safe to perform lung transplants on critically ill patients, even those suffering from infectious causes of lung failure, such as COVID-19.
And there was another silver lining: Despite the use of immune-suppressing drugs in lung transplant patients, the coronavirus that causes COVID-19 did not seem to return.
The team also found that in COVID-19 patients whose lungs are so damaged that they won’t survive without a lung transplant, it’s safe to place them on ECMO (extracorporeal membrane oxygenation)—a life support machine that does the work of the heart and lungs.
ECMO can be used for an extended period of time and still leave the door open for a successful lung transplant, the team said.
One author of the study is Dr. Ankit Bharat.
The study is published in Science Translational Medicine.
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