Activity of the human immortalized endothelial progenitor cell line HEPC-CB.1 supporting in vitro angiogenesis.

The human HEPC-CB.1 cell line with many characteristics of endothelial progenitor cells (EPC) was tested for its proangiogenic properties as a potentially therapeutic compound. HEPC-CB.1 cells' potential to differentiate into endothelial cells was revealed after treating the cells with a mixture of ATRA, cAMP and VEGF, as shown by the reduced expression levels of CD133, CD271 and CD90 antigens, augmentation of CD146 and CD31, and a decrease in cell clonogenicity. The cooperation of HEPC-CB.1 with the endothelial cell line HSkMEC.2 resulted in the formation of a common network. Tube formation was significantly more effective when resulting from HEPC-CB.1 and HSkMEC.2 cell co-culture as compared to a monoculture of each cell line. The exocrine mechanism of HEPC-CB.1 and HSkMEC.2 cross talk by secreted factors was evidenced using the HEPC-CB.1 supernatant to increase the efficacy of HSkMEC.2 tube formation. The proangiogenic factors produced by HEPC-CB.1 were identified using cytokine antibody array. Out of 120 examined factors, the HEPC-CB.1 cell line produced 63, some with known angiogenic activity. As in vivo the angiogenic process occurs at low oxygen tension, it was observed that in hypoxia, the production of defined factors was augmented. The presented results demonstrate that HEPC-CB.1 cells are able to both cooperate and integrate in a newly formed network and produce factors that help the network formation. The results suggest that HEPC-CB.1 cells are indeed endothelial progenitors and may prove to be an effective tool in regenerative medicine.

Increased Endothelial Progenitor Cell Number in Early Stage of Endometrial Cancer.

OBJECTIVES: It is generally believed that circulating endothelial cells (CECs) and endothelial progenitor cells (EPCs) reflect the state of the endothelium, its injury and/or repair possibilities. In different types of cancers, increased numbers of CECs and EPCs were found, suggesting their participation in cancer angiogenesis. The objective of this study was to determine whether, in the blood circulation of women with early endometrial cancer, CEC and EPC levels differ from those of healthy women of similar age. METHODS: For CEC number evaluation, samples of peripheral blood cells of women with endometrial carcinoma and control subjects were labeled with anti-CD31 and anti-CD45 antibodies; for EPCs, with anti-VEGFR2 (vascular-endothelium growth factor receptor 2)/KDR and anti-CD34 antibodies. The CEC and EPC cells were then quantified by flow cytometry. RESULTS: Endothelial progenitor cell numbers (CD34, VEGFR2/KDR) in the peripheral blood of women with endometrial carcinoma were significantly augmented as compared with those of control healthy women and CEC numbers (CD31, CD45) were similar in both groups. Cancer patients were divided according to the grading into G1 and G2 groups and according to the stage into International Federation of Gynecology and Obstetrics (FIGO) stage IA and FIGO IB groups. Statistically significant augmented EPC numbers were demonstrated only in G1 and FIGO IA patients. CONCLUSIONS: These results strongly suggest new vessel formation from recruited endothelial precursors as being involved mainly at the early stages of tumor progression.

Pregnancy-induced hypertension is accompanied by decreased number of circulating endothelial cells and circulating endothelial progenitor cells.

Maternal endothelial dysfunction is one of the main features of pregnancy-induced hypertension (PIH). It is generally accepted that circulating endothelial cells (CECs) and endothelial progenitor cells (EPCs) reflect the state of the endothelium, its injury and/or repair possibilities. The objective of this study was to determine whether the CECs and EPCs numbers in the circulation of women with PIH reflect the presence of this pathology. Peripheral blood cells of PIH and normotensive pregnant women were labeled with specific monoclonal antibodies. For CECs evaluation, samples were labeled with anti-CD31 and anti-CD45 antibodies; for EPCs with anti-VEGFR2/KDR and anti-CD34 antibodies. Cells were quantified by flow cytometry. The levels of both CECs (CD31(+), CD45(-)) and EPCs (CD34(+), VEGFR2/KDR(+)) in the peripheral blood of women with PIH were significantly lower compared with those of control pregnant women with normal blood pressure level. Lowered accessibility of maternal CECs and EPCs may diminish general regenerative potential of the patient endothelia, contributing to PIH symptoms and to the risk of subsequent coronary and arterial disease.

Reduced number of circulating endothelial progenitor cells (CD133+/KDR+) in patients with plaque psoriasis.

BACKGROUND: Psoriasis is associated with an increased cardiovascular risk. Circulating endothelial progenitor cells (CEPCs) play a significant role in the maintenance of vascular homeostasis. OBJECTIVE: The aim of this study was to evaluate the number of CEPCs in patients with psoriasis compared to controls and assess possible correlations between the number of these cells and the plasma levels of vascular endothelial growth factor (VEGF), soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and clinical features of psoriasis. METHODS: The number of CEPCs, identified as CD133+/KDR+ cells, was determined with flow cytometry in peripheral blood of psoriatic patients (n = 63) and controls (n = 31). The plasma levels of VEGF and sVEGFR-1 were measured with enzyme-linked immunosorbent assay. RESULTS: The number of CEPCs was significantly reduced in psoriatic patients compared with controls (p = 0.000026) and inversely correlated with disease severity (R = -0.283; p = 0.0248). CONCLUSION: A reduced number of CEPCs may contribute to endothelial dysfunction in patients with psoriasis.

CD133 positive progenitor endothelial cell lines from human cord blood.

Endothelial progenitor cells (EPCs) modulate postnatal vascularization and contribute to vessel regeneration in adults. Stem cells and progenitor cells were found in umbilical cord blood, bone marrow, and mobilized peripheral blood cells, from where they were isolated and cultured. However, the yield of progenitor cells is usually not sufficient for clinical application and the quality of progenitor cells varies. The aim of the study was the immortalization of early progenitor cells with high proliferative potential, capable to differentiate to EPCs and, further, toward endothelial cells. Two cell lines, namely HEPC-CB.1 and HEPC-CB.2 (human endothelial progenitor cells-cord blood) were isolated. As assessed by specific antibody labeling and flow cytometric analysis, they express a panel of stem cell markers: CD133, CD13, CD271, CD90 and also endothelial cell markers: CD202b, CD309 (VEGFR2), CD146, CD105, and CD143 but they do not present markers of finally differentiated endothelial cells: CD31, vWf, nor CD45 which is a specific hematopoietic cell marker. Using the multiplex Cytometric Bead Assay, the simultaneous production of proangiogenic cytokines IL8, angiogenin, and VEGF was demonstrated in normoxia and was shown to be increased by hypoxia. Both cell lines, similarly as mature endothelial cells, underwent in vitro pre-angiogenic process, formed pseudovessel structures and present an accelerated angiogenesis in hypoxic conditions. To date, these are the first CD133 positive established cell lines from human cord blood cells.