Kinetics of mesenchymal and hematopoietic stem cells mobilization by G-CSF and its impact on the cytokine microenvironment in primary cultures

• G-CSF administration increases the frequency of stem cells.
• G-CSF administration potentiates stem cells to release soluble factors.
• Stem cells harvested from bone marrow and peripheral blood display differential functional properties.
• Stem cells are promises for future clinical applications and regenerative medicine.

In this study, we demonstrate that G-CSF administration triggers distinct kinetics of stem cell-SC mobilization with early raise of hematopoietic-HSC and late increase of mesenchymal-MSC in bone marrow-BM and peripheral blood-PB. The cytokine microenvironment observed following primary cultures showed an overall G-CSF dose-dependent profile with a clear mixed pro-inflammatory/regulatory pattern. Moreover, primary cultures performed at the peak of MSC/HSC ratio, showed distinct cytokine patterns, with higher IL-10, TNF-α and IL-17A observed for BM and enhanced IL-10, IL-2 and IFN-γ for PB harvested cells. Positive correlation was observed between BM-MSC and the levels of TNF-α, IL-10 and IL-17A whereas negative correlation was found between IL-10 and BM-HSC. An opposite association was observed between IL-10 and PB-HSC. Our results support the hypothesis that MSC and HSC harvested from BM and PB display differential functional properties that should be considered when electing the SC sources available for cell therapy applied in clinical protocols.