Table 1: Differences between eEPCs and lEPCs.

Early EPCsLate EPCs

SynonymsCACs [82]OECs [83, 91] or ECFCs [84]
Cell population [81, 91]HeterogeneousHomogenous
Cell morphology [81]Spindle-shaped cellsCobblestone-like cells
Appearance in culture<1 week [5, 81]2–4 weeks [81]
Lifespan [81]3-4 weeks≈12 weeks
Morphogenic potential [81]LowHigh
Angiogenic potential [81]GoodGood
Tube formation in vitro [5, 92, 134]
Tube formation by EPCs aloneAbsentPresent
Tube formation by EPCs with HUVECsAbsentPresent
Tube formation in vivo [92]AbsentPresent
Neovascularization in vivo [82, 92, 93, 134]Indirect paracrine fashionDirectly providing ECs; hence can be referred to as “true EPCs”
Surface expression
CD34 [88, 134]++
CD45 [81, 88, 134]+
CD14+ and − [91, 93]/+ [92]
CD133− [88] and + [89, 136]− [88, 89, 136]
CD31 (PECAM 1) [81, 134, 137]−/+++
VEGFR-2 [81, 92, 93, 134, 137]−/+++
VE cadherin [81, 93, 134]−/+++
vWf [81]−/++
Phenotype [90]MonocyticEndothelial
AcLDL uptake [5]+++
Lectin binding [5]+++
NO production [5]+++

+: present; ++: strongly present; −: absent; and −/+: limited/weak/focal.