Tracey Bonfield, PhD

American Lung Association Obstructive Lung Disease Scholar

Much of the illness caused by asthma is associated with abnormal activation of the immune system. The inflammation in the airways of a person with asthma is continuous and robust, which can ultimately result in airway remodeling and structural changes. This in turn can lead to reduced lung function. There are many pharmaceutical therapies used in asthma, but some people’s asthma cannot be controlled with current treatments. Tracey Bonfield, PhD, is studying mesenchymal stem cells as a potential new treatment in uncontrolled chronic asthma. These stem cells, produced in the bone marrow, are precursor cells. This means that they can grow into a variety of different types of cells throughout the body. Mesenchymal stem cells have been shown to repress inflammation and the activity of immune cells called T cells, both major contributors to asthma.

Using an American Lung Association Biomedical Research Grant, Dr. Bonfield is studying mesenchymal stem cells’ effects on animal models of acute and chronic asthma that mimic many of the disease characteristics seen in human asthma. The model imitates exacerbations seen in an acute episode of asthma. The chronic model mimics many of the hallmarks of chronic asthma, with airway remodeling and decreased lung function.

“We have been able to demonstrate that mesenchymal stem cells have the unique capacity to reverse many of the pathologies of chronic and acute asthma.”
“We have been able to demonstrate that mesenchymal stem cells have the unique capacity to reverse many of the pathologies of chronic and acute asthma using these models of human asthmatic lung disease,” Dr. Bonfield says. “Although we have found that the mesenchymal stem cells have this capacity, we still don’t know how they are doing it.” The current focus is on examining three possibilities: whether the changes are caused by the cells themselves, whether they are the result of a products made by the cells, or whether they are a result of communication between the stem cells and the body, which allows the body to repair itself.

“If the changes are caused by mesenchymal cells, it might be possible to create a potential therapy based on the findings,” Dr. Bonfield states. “If the treatment requires products produced by the stem cells themselves, it might mean that patients would have a new product they could take, as they do with current asthma therapy.” Both of these options may require more than one dosing. However if the cell-based therapy actually changes the body’s immune system, it might be possible to give the treatment once and the cells would then take over, continually making what the body needs to fight the changes in the lung. Dr. Bonfield’s laboratory is studying how long these stem cells would be effective in treating asthma in this case.