CHARACTERIZATION AND ISOLATION OF VERY SMALL EMBRYONIC-LIKE (VSEL) STEM CELLS OBTAINED FROM HUMAN PERIPHERAL BLOOD

Objective: Stem cell transplantation is considered to be one of the available treatments for malign or hereditary blood diseases and bone marrow failure. Peripheral blood progenitor cells (PBPC) are widely used for this technique. Recently a new type of stem cell with a pluripotent potential has been identified. These cells, called very small embryonic-like (VSEL) stem cells, are thought to be found in peripheral blood (PB) in adult individuals. The aim of this study was to obtain and identify VSEL stem cells using a peripheral blood source. Material and Method: VSEL cells were isolated from mononuclear and erythrocyte layers obtained by using lysis and ficoll gradient methods from the materials taken from donors. The presence of NANOG, OCT4, SSEA-4 and CXCR-4 embryonal stem cell markers by flow cytometry and immunofluorescence staining was investigated. The presence of NANOG and OCT4 proteins was investigated using the Western blot method. Results: According to the flow cytometry results, the number of cells carrying the VSEL marker was higher in the debris layer than in the CD45-population. Western and immunofluorescence results showed high levels of OCT4 and NANOG expression. It was also determined that these proteins are present in both the cytoplasm and the nucleus. Conclusions: High expression of these proteins, known as pluripotent stem cell markers, in adult peripheral blood brings to mind the question of how they work in differentiated tissues. These findings strengthen the thesis of a new stem cell population that have pluripotent markers in peripheral blood and provide the basis for future clinical studies about this point.