. 2014 Jun 13;23(19):2263–2273. doi: 10.1089/scd.2014.0197

Table 1.

Schematic Representation of the Heart as Composed of a Mosaic of Different Progenitor Cell-Populations Identified in the Myocardium

		In vitro differentiation			In vivo differentiation
Ref.	Phenotype	CM	EC	SMC	CM	EC	SMC	Clonogenic
[25]	Sca-1⁺ Ftl-1⁻ Flk-1⁻ CD31⁺ CD34⁻ CD45⁻	4.6%	nd	nd	<1%^a	nd	nd	nd
[22]	Sca-1⁺ c-Kit⁻ CD34⁻ CD31⁻ CD45⁻ CD90⁺ CD105⁺ CD29⁺ CD44⁺ CD106⁺ CD73⁺ CD13⁺	1.24%	12.4%	31.9%	100^b	80^b	120^b	+
[23]	Sca-1⁺ PDGFRα⁺ CD31⁻ CD45⁻ CD90⁺ CD105⁺ CD29⁺ CD44⁺ Flk-1⁻	+	+	+	+	+	+	+
[24]	Sca-1⁺ c-Kit⁻ CD34⁻ CD31⁻ CD45⁻ CD29⁺	<1%	∼4.5%	∼30%	+	+	nd	+
[39]	Sca-1⁺ PDGFRα⁺ CD44⁺ CD105⁺ CD29⁺ CD31⁻ CD45⁻ Flk-1⁻ c-Kit⁻ CD34⁻ CD31⁻ CD45⁻ CD90⁻	+	∼1.75%	∼27%	∼9^c	∼4^c	∼41^c	+
	Side population
[13]	Sca-1⁺ c-Kit⁻ Flk-2⁻ CD34⁻ Thy1.1⁻	nd	nd	nd	nd	nd	nd	+
[14]	Sca-1⁺ Abcg2⁺ c-Kit^low CD45^low CD34^low CD31⁻	+	nd	nd	nd	nd	nd	nd
[15]	Sca-1⁺ c-Kit⁻ CD31⁻ CD45⁻ CD44⁻ CD34⁻	+	nd	nd	nd	nd	nd	+
[16]	CD29⁺CD31^+/− CD45^+/−	5.5%	nd	nd	4.4%	6.7%	29%	nd
[17]	Sca-1⁺ VE-cadherin⁻ CD34⁺ CD73⁺ CD90⁺ CD105⁺ CD45⁻	+	nd	nd	nd	nd	nd	nd
	Epicardial-derived progenitors
[92]	Sca-1⁺ c-Kit⁻ CD31⁻ Flk-1⁻	nd	nd	nd	+	nd	nd	nd
	Sphere formation (cardiospheres)
[18]	Sca-1⁺ c-Kit⁺ CD31⁺ CD34⁺ Flk-1⁺	+	+	+	+	+	+	+
[19]	Sca-1⁺ c-Kit⁻ CD31⁻ CD34⁻ CD45⁻ CD29^low CD133⁻ Flk-1⁻	∼60%	∼20%	∼34%	∼10%	∼10%	∼10%	+
	c-Kit⁺ cells
[20]	c-Kit⁺ CD45⁻ CD34⁻ CD20⁻ CD45RO⁻ CD8⁻ Ter119⁻	+	+	+	+	+	+	+
[21]	c-Kit⁺ CD29⁺ CD44⁺ CD105⁺ CD90⁺	+	+	+	nd	nd	nd	nd

A variety of procedures have been adopted to isolate and purify a cardiac progenitor cells panoply, either based on the expression of the stemness-associated surface markers Sca-1 and c-Kit, the ability to efflux dyes (eg, rhodamine and Hoechst 33342)—SP, to grow as 3D multicellular clusters—CSs or by the expression of a specific genetic marker—Wt-1 epicardial progenitors. The isolated population have been subjected to phenotypic characterization and their multipotency, that is, the ability to differentiate in CMs, ECs, and SMCs, has been tested in vitro and/or in vivo, as well as the clonogenic potential. A concise summary of these results is displayed with indication of whether differentiation into a specific cell type was observed (+) in vitro and/or in vivo or if it was nd in the specific study.

^{^a}

Percentage of diffentiated myocytes.

^{^b}

Cells/mm².

^{^c}

Cells/heart section.

CMs, cardiomyocytes; CSs, cardiospheres; ECs, endothelial cells; nd, not determined; Sca-1, stem cell antigen-1; SMC, smooth muscle cell; SP, side population.