Korean Circ J.  2015 Jul;45(4):325-332. 10.4070/kcj.2015.45.4.325.

Absence of Correlation between Changes in the Number of Endothelial Progenitor Cell Subsets

• Attar A
• Aghasadeghi K
• Parsanezhad ME
• Namavar Jahromi B
• Habibagahi M

• KMID: 1964105
• DOI: http://doi.org/10.4070/kcj.2015.45.4.325

Abstract

BACKGROUND AND OBJECTIVES
Previously, various methodologies were used to enumerate the endothelial progenitor cells (EPCs). We now know that these methodologies enumerate at least three different EPC subsets: circulating angiogenic cells (CACs), colony-forming unit endothelial cells (CFU-ECs), and endothelial colony-forming cells (ECFCs). It is not clear whether there is a correlation between changes in the number of these subsets. The aim of the current study is to find an answer to this question.
MATERIALS AND METHODS
The number of all EPC subsets was quantified in the peripheral blood of nine pregnant women in their first and third trimesters of pregnancy. We enumerated 14 cell populations by quantitative flow-cytometry using various combinations of the markers, CD34, CD133, CD309, and CD45, to cover most of the reported phenotypes of CACs and ECFCs. Culturing technique was used to enumerate the CFU-ECs. Changes in the number of cells were calculated by subtracting the number of cells in the first trimester peripheral blood from the number of cells in the third trimester peripheral blood, and correlations between these changes were analyzed.
RESULTS
The number of CFU-ECs did not correlate with the number of ECFCs and CACs. Also, CACs and ECFCs showed independent behaviors. However, the number of CACs showed a strong correlation with the number of CD133+CD309+ cells (p=0.001) and a moderate correlation with the number of CD34+CD309+ cells (p=0.042). Also, the number of ECFCs was correlated with the number of CD309+CD45- cells (p=0.029) and CD34+CD45- cells (p=0.03).
CONCLUSION
Our study showed that the three commonly used methods for quantifying EPC subsets represent different cells with independent behaviors. Also, any study that measured the number of EPCs using the flow cytometry method with a marker combination that lacks CD309 may be inaccurate.

Keyword

Endothelial progenitor cells; Endothelium

MeSH Terms

Endothelial Cells
Endothelium
Female
Flow Cytometry
Humans
Phenotype
Pregnancy
Pregnancy Trimester, First
Pregnancy Trimester, Third
Pregnant Women
Stem Cells*

Figure

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  Fig. 1 Typical density plot diagrams defining some of the variable regions used to enumerate absolute counts of the circulating angiogenic cells marked as CD34+CD133+CD309+CD45+ cells.

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  Fig. 2 A typical colony of colony forming unit endothelial cells.

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  Fig. 3 Box plot defining the median and range of the number of CACs in the 1st and 3rd trimester peripheral blood. Number of CACs increases as the gestational age advances, but it only reaches significance when it is reported as the number of cells in a milliliter of blood. This shows that the way of reporting the data affects the final results. CAC: circulating angiogenic cell.

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