The first evidence of cardiac progenitor cells &endash; rare, specialized stem cells located in the newborn heart of rats, mice and humans &endash; has been shown by researchers at the UCSD School of Medicine. The cells are capable of differentiation into fully mature heart tissue.
Called isl1 cells, these cardiac progenitor cells are stem cells that have been programmed to form heart muscle during fetal growth. Until this new discovery, the cells were thought to be absent after birth. However, the UCSD team discovered a small number of the specialized stem cells remained embedded in a region of the newborn heart called the atrium. They also determined that the cells could be expanded into millions of progenitor cells by growing them on a layer of neighboring heart cells called fibroblasts.
Published in the February 10, 2005 issue of the journal Nature, the research identified the isl1 progenitor cells in the tissue of newborn rats and mice, and then in heart tissue taken from five newborn human babies undergoing surgery for congenital heart defects.
Study author Sylvia Evans, Ph.D., a member of the UCSD Institute of Molecular Medicine (IMM) and professor of pharmacology, and co-first author Alessandra Moretti, Ph.D., IMM member, explained that the cells are programmed to become spontaneously beating cardiac muscle cells simply by exposure to other neighboring heart cells.
