Endothelial Outgrowth Cells Are Not Derived From CD133 ⁺ Cells or CD45 ⁺ Hematopoietic Precursors

Abstract

Objective-Two types of endothelial progenitor cells (EPCs), early EPCs and late EPCs (also called endothelial outgrowth cells [EOCs]), were described in vitro previously. In this report, we dissect the phenotype of the precursor(s) that generate these cell types with focus on the markers CD34, CD133, and vascular endothelial growth factor receptor-2 (VEGFR2) that have been used to identify putative circulating endothelial precursors. We also included CD45 in the analysis to assess the relation between CD34 ϩ hematopoietic progenitors (HPC), CD34 ϩ endothelial precursors, and both in vitro generated EPC types. Addressing this issue might lead to a better understanding of the lineage and phenotype of the precursor(s) that give rise to both cell types in vitro and may contribute to a consensus on their flowcytometric enumeration. Methods and Results-Using

CD133+ circulating haematopoietic progenitor cells predict for response to sorafenib plus erlotinib in non-small cell lung cancer patients

“…However, present studies point to a limited incorporation of bone marrow-derived cells into the endothelium of tumours (Peters et al, 2005). Many recent studies and reviews discuss the properties of pro-angiogenic cell populations or 'circulating angiogenic cells' in depth (Case et al, 2007;Timmermans et al, 2007Timmermans et al, , 2008Hirschi et al, 2008;Gao et al, 2009;Yoder and Ingram, 2009). A specific role of CD133 þ /HPCs has been suggested in pulmonary vascular remodelling in patients with obstructive pulmonary disease (Asosingh et al, 2008) or idiopathic pulmonary arterial hypertension (Diez et al, 2007).…”

“…The population of CECs that we have monitored has a phenotype consistent with a population containing the precursor for EOCs, namely CD34 þ , VEGFR2 þ , but CD45 À and CD133 À (see Figure 1) according to Case et al (2007) and Timmermans et al (2007). However, whether CECs are a mixed mature/progenitor population will only be determined once these very rare cells can be sorted after a unique specific marker of the endothelial progenitor cell will have been identified (Yoder and Ingram, 2009).…”

Generation of T Cells from Human Embryonic Stem Cell-Derived Hematopoietic Zones

“…On the one hand, cells with hematopoietic precursor activity seem to partially retain membrane molecules of their hemogenic or hemangioblastic precursors, such as VE-cadherin and VEGFR-2 (supplemental Table S1) (15). This is different from the BM stem cell compartment, where hematopoietic stem cells are believed to be no longer continuously generated from precursors and are devoid of these markers (24,25). In contrast, they acquire membrane markers such as CD45, which are expressed on all postnatal HSC/HPC.…”

Endothelial Outgrowth Cells: Function and Performance in Vascular Grafts

“…19,33,34 The scarcity of these progenitors in peripheral blood has been the greatest challenge in their characterization. From a translational standpoint, the low frequency in blood reduces the probability of successful outgrowth from any given blood draw.…”