Two distinct populations of cells have previously been identified as cardiac progenitors, giving rise to different areas of the developing heart. Scientists in the USA and the UK have now come together to add a third myocardial lineage to the list.
A recent report from Cai et al. has identified pluripotent cardiac cells in mice that develop into myocytes in the heart wall in addition to cardiac fibroblasts and coronary smooth muscle cells. These stem cells originate in the proepicardium and express the T-box transcription factor Tbx18, which is also found at sites of heart regeneration in zebrafish.
The identification of new cardiac stem cell populations should lead to better understanding the mechanisms underlying heart development and congenital defects. As we accumulate information on how these cells maintain pluripotency and differentiate, they may play an important role in regenerative medicine for congenital defects or acquired heart disease.
