Researchers Describe Origins Of New Heart Cells

http://www.stemcellresearchnews.com/absolutenm/anmviewer.asp?a=3034&z=9
BOSTON, Mass., December 5, 2012 C Recent research has shown that there are new cells that develop in the heart, but how these cardiac cells are born and how frequently they are generated remains unclear.

In new research from Brigham and Women's Hospital (BWH), researchers use a novel method to identify these new heart cells and describe their origins.

A sophisticated imaging system (Multi-isotope Imaging Mass Spectrometry, or  MIMS) demonstrates cell division in the adult mammalian heart.

��The question about how often cardiac cells are born has been extremely difficult to answer because there was a need for new techniques to help us understand this process. We are especially excited about our findings because of the novel way in which were able to show new heart cells, using MIMS.

The team of BWH researchers marked existing cardiac cells genetically to cause them to express a green fluorescent protein. Then they used MIMS to examine the development of new heart muscle cells, called cardiomyocytes, in a preclinical model over a period of months. Researchers were surprised to find that new heart muscle cells primarily arose from existing heart muscle cells, rather than stem cells. Even in the setting of a heart attack, when stem cells are thought to be activated, most new heart cells were born from pre-existing heart cells.

Our data show that adult cardiomyocytes are primarily responsible for the generation of new cardiomyocytes and that as we age, we lose some capacity to form new heart cells,said Dr. Lee. This means that we are losing our potential to rebuild the heart in the latter half of life, just when most heart disease hits us. If we can unravel why this occurs, we may be able to unleash some heart regeneration potential.

Citation: Mammalian heart renewal by pre-existing cardiomyocytes; Samuel E. Senyo et al.; Nature, 5 December 2012; DOI: 10.1038/nature11682