GRAND RAPIDS, Mich. (WOOD) – A new study published by researchers at the University of Michigan may have found out how COVID-19 causes long-term breathing problems in certain people.
The findings, published in “The American Journal of Pathology,” found that some people who experienced a serious infection had a breakdown in a specific cell cycle in their lungs, leaving them scarred and preventing the lungs from healing.
“The stem cells that are trying to repair the lungs do not complete that repair process. They get hung up at some point,” Dr. Rachel Zemans told News 8.
Zemans, a professor of internal medicine at the University of Michigan, has been researching the healing process of the respiratory system for more than 15 years. This study focused on individuals who had severe COVID-19 infections, who were admitted to intensive care units and, in most cases, put on ventilators.
“Of these severe COVID patients, we group them in a way into three categories,” Zemans said. “Some patients die, and as you know, nearly a million Americans have died from COVID. Some patients get better, and when they get better, they have pretty normal lungs, normal lung structure and function, and they go home. And then there is a third category where people survive but they have scarring and it can result in lifelong respiratory symptoms like cough and shortness of breath. “
She says the scarring seen in COVID-19 patients is similar to bad cases of pneumonia, which can leave the body with chronic fibrotic lung disease. These scars damage a specific part of the lungs: the epithelium.
The epithelium is the part of the lung that acts as a filter that protects the lungs from pathogens and other foreign bodies. The epithelium is made up of two types of cells – one that covers most of the surface and one that works with the other to inflate the lungs and remove fluid.
Studies in mice have shown that when the lung is dealing with an infection and these surface cells are damaged, the second type of cell passes into the other to help the lungs heal. But in rare cases, these cells get stuck in the transition that the lungs do not heal and eventually get scars.
Right now, health experts do not know how to regenerate these cells or push them through this transition to restart the healing process.
“If we can understand how to get these cells over the hump and push them towards completing this normal repair process, we could hopefully help the patients who should die to survive and then the survivors who get the scarring, prevent the scarring, ”Zemans said.