Studies Raise Doubt About Ability of Stem Cells To Repair Damaged Heart Tissue
Two studies, one co-authored by a physician-scientist from Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, shed doubt on the reported ability of certain transplanted stem cells to repair damaged heart tissue.
The papers, to be published online by Nature on March 21, find no evidence to suggest that hematopoietic stem cells, which usually produce blood cells, can turn into heart cells after injection into that organ. Such "transdifferentiation" has previously been reported and led to excitement in both the scientific literature and lay press concerning the potential for new avenues of treatment for heart attacks.
In the research involving David A. Williams, MD, Beatrice C. Lampkin, MD, chair of Pediatric Oncology and director of the Division of Experimental Hematology at Cincinnati Children's, bone-marrow-derived hematopoietic stem cells were injected into the damaged hearts of living mice. The researchers then followed the injected cells' fate via the use of various marker proteins. Although some of the transplanted cells seemed to survive, they did not appear to differentiate into new heart muscle cells. Instead they matured into cells of the traditional blood lineage.
The team was led by Charles E. Murry, MD, PhD, of the University of Washington. Similar findings were reported in an independent study published in the same issue of Nature led by Leora B. Balsam, MD, of Stanford University.
"These studies add to the growing body of information demonstrating that the potential use of blood stem cells to treat diseases outside the blood system needs additional study," says Dr. Williams. "While still an exciting potential new therapy for a variety of diseases, including heart disease, these additional studies are needed to define if the fate of blood stem cells can be controlled and, if so, how these cells can be safely utilized to assist in the repair of other organs."
In addition, only one of the two studies observed modest benefits in some aspects of heart function after the procedures, which the authors suggested to be from the stimulation of new blood vessels in the heart. The results raise a cautionary note for interpreting the results of ongoing clinical studies where hematopoietic stem cells are injected into the heart after a heart attack.
Contact Information
Jim Feuer, 513-636-4656,
jim.feuer@cchmc.org
