Human cardiac muscle cells (cardiomyocytes) have a limited capacity for renewal, which is not sufficient to prevent heart failure after a heart attack. Stem cell therapy techniques can improve function after injury, but until recently scientists still wondered at the specific mechanism by which these strategies work. New research from HSCI Principal Faculty Member Richard Lee demonstrates how the technique helps the body regenerate new cardiomyoctyes. First, Lee's team induced heart attack in mice whose native cardiomyocytes were distinguishable from transplanted cells. Next, they introduced a secondary population of bone-marrow cells, called c-Kit cells, that was previously reported to improve cardiac function after injury. As expected, the treatment allowed the body to grow new cardiac muscle cells but these were neither related to the original distinguishable population nor demonstrated traits characteristic to the secondary cell population. Additionally, the researchers were able to show that a second cell population, mesenchymal stem cells, did not have the same effect. These data indicate that the c-kit cells repair heart muscle by activating cardiomyocyte progenitor cells, rather than by transforming themselves into cardiomyoctyes or by restoring function to injured cells. Knowing the mechanism by which this cell therapy works will allow researchers to identify new, less invasive forms of treatment for cardiac patients, such as pharmacological options.
Loffredo, F.; Steinhauser, M.; Gannon, J.; Lee, R. (2011) Bone Marrow-Derived Cell Therapy Stimulates Endogenous Cardiomyocyte Progenitors and Promotes Cardiac Repair. Cell Stem Cell 389 – 398.