Figure 1.

Cardiosphere isolation and markers.A) Cardiosphere isolation protocol. Cardiac explants are seeded in fibronectin-coated plates; after 2–3 days cells leave the explants and invade the plate where they start to proliferate. One week after, a population of loosely attached round bright cells appears, this population give rise to cardiospheres. B) Immunofluorescence analysis for cardiac, myofibroblast and endotheial markers in cultivated cardiospheres. Cardiospheres showed cells expresing c-kit and Sca-1. Presence of c-kit-positive cells are predominat in the core of the culture and relatively low in places that are positive for the proliferation marker Ki67. In contrast Sca-1+ cells are present uniformly in the whole culture. Cultures are also positive for Gata4, Cx43 and Mef2c cardiac markers. Expression of vascular markers, such as CD31 and SMA, was low.