Isolation and expansion of adult cardiac stem/progenitor cells in the form of cardiospheres from human cardiac biopsies and murine hearts.

The successful isolation and ex vivo expansion of resident cardiac stem/progenitor cells from human heart biopsies has allowed us to study their biological characteristics and their applications in therapeutic approaches for the repair of ischemic/infarcted heart, the preparation of tissue-engineered cardiac grafts and, possibly, the design of cellular kits for drug screening applications. From the first publication of the original method in 2004, several adjustments and slight changes have been introduced to optimize and adjust the procedure to the evolving experimental and translational needs. Moreover, due to the wide applicability of such a method (which is based on the exploitation of intrinsic functional properties of cells with regenerative properties that are present in most tissues), the key steps of this procedure have been used to derive several kinds of tissue-specific adult stem cells for preclinical or clinical purposes.In order to define the original procedure, complete with the up-to-date modifications introduced through the years, an exhaustive description of the current protocol is performed in this chapter, with particular attention in highlighting critical steps and troubleshoots. The procedure described here consists of modular steps, that could be employed to derive cells from any kind of tissue biopsy, and needs to be considered the gold standard of all the so-called "explant methods" or "cardiosphere methods," and it represents a milestone in the clinical translation of autologous cell therapy.