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.
And, since these rare cardiac progenitor cells are found in regions of the atrium that are normally discarded during routine cardiac surgery, the discovery raises the possibility that an individual could receive their own cardiac stem cells to correct a wide spectrum of pediatric cardiac diseases, according to co-first authors Moretti and Karl-Ludwig Laugwitz, M.D., a Heisenberg-Scholar of the German Research Foundation.
"Conceptually, these cells could provide a cell-therapy based approach to pediatric cardiac disease,
Contact: Sue Pondrom
University of California - San Diego