This study published in the journal Nature reported that injecting living or even dead heart stem cells into the injured hearts of mice triggers an acute inflammatory process which in turn generates a wound healing-like response to enhance the mechanical properties of the injured area. Mediated by macrophage cells of the immune system the secondary healing process provided a modest benefit to heart function after a heart attack according to the principal investigator Jeffery Molkentin PhD director of Molecular Cardiovascular Microbiology a Cincinnati Children's Hospital Medical Center and a professor of the Howard Hughes Medical Institute (HHMI). The innate immune