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Stem Cells Show Promise in Halting Heart Attack's Ripple Effect

Several recent clinical trials have shown how stem cells can help the heart heal after an attack, but to date the investigations have focused on transplanting cells directly into the site of the attack itself. However, a heart attack has a ripple effect, much like how an earthquake reaches beyond its epicenter to affect outlying regions, too. As the heart attempts to shift the workload from the damaged section to surrounding healthy muscle, the tissue abutting the attack site gets caught in the middle. This often results in the tissue being overstressed and leads to cardiac failure.

In this new study, the researchers evaluated the effects of expanding the stem cell treatment beyond the heart attack site to include the surrounding region.

"We wanted to look specifically at whether mesenchymal stem cells (MSCs) improve the remodeling of the myocardium directly abutting the attack site," explained Zhongium Wu, Ph.D., associate professor of surgery at the University of Maryland School of Medicine and a principal investigator in the study. "In other words, could they prevent changes to the heart's size, shape, structure and physiology resulting from the injury to its muscular tissue?"

Using pre-clinical models, researchers treated half of the group with MSCs and left the other half untreated. Each subject receiving the MSCs was treated with allogeneic stem cells to prevent rejection. The MSCs were collected from the bone marrow, then modified in the lab before being re-transplanted using a series of six injections. MSCs were employed because they give rise to a variety of cell types. Three months later, they examined the results and were excited by what they found.

"Along with protecting the adjacent area from structural damage and strain, the MSCs prevented other common side effects of a heart attack including cardiac hypertrophy, or enlargement, which is generally the result of an imbalance in calcium brought on by an attack. They also reduced cardiac apoptosis in which the heart cells basically commit suicide," said Bartley P. Griffith, M.D., Thomas E. and Alice Marie Hales Distinguished Professor, professor of surgery at the University of Maryland School of Medicine and director of heart and lung transplantation at the University of Maryland Comprehensive Heart Center. He and Dr. Wu, along with Zhao Yunshan, Ph.D., and Tieluo Li, M.D., made up the study's leadership team.

"We believe the study provides an important view into how MSC transplantation may benefit the region adjacent to the heart attack site, said Griffith. The results merit further investigation."

"This study provides new evidence detailing the therapeutic effects of MSC transplantation on progressive cardiac remodeling following a heart attack," said Anthony Atala, M.D., Editor of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine.

The full article, "Mesenchymal Stem Cell Transplantation Improves Regional Cardiac Remodeling Following Ovine Infarction," can be accessed here