Cellular profile of hematopoietic stem cells mobilized by exercise versus G-CSF in healthy related donors

Hematopoietic stem cell transplantation (HSCT) depends on effective HSC mobilization with granulocyte colony-stimulating factor (G-CSF), though some allogeneic donors experience severe side effects. This study compares G-CSF and acute maximal exercise for HSC collection and cellular composition in 10 healthy family donors, examining links to donor fitness and recipient outcomes.

Ten donors (3 females; 40.8 (18.3) years) and their recipients (n = 8; 3 females; 47.5 (18.5) years) were enrolled. Donors completed cardiopulmonary exercise testing with blood samples taken pre- and post-exercise and on apheresis day for flow cytometric analysis. Recipients were followed up on day ~ 30 post-transplant.

Exercise significantly increased circulating total CD34+ cells (1.76-fold (0.51), p = 0.002) and select progenitor subsets (CD34+CD45dim, 1.74-fold (0.56), p = 0.006; and CD34+CD38+CD133+, 1.60-fold (0.46), p = 0.013), while other subsets showed no significant change (p > 0.05). Compared with post-exercise, apheresis resulted in markedly higher concentrations of total CD34+ cells (20.7-fold (9.7), p < 0.001) and all measured subsets. The largest enrichments were observed in CD34+ CD38-CD133+ (52.7-fold (69.3) p = 0.005) and CD34+CD38+CD133+ (38.2-fold (17.0), p < 0.001) populations. HSC collection at apheresis contained a 186.1-fold (72.3) elevation of immature granulocytes (p < 0.001) compared to the acute exercise (1.5-fold (0.3)). The proportions of apoptotic CD34+ cells and their subpopulations were similar post-exercise to apheresis (p > 0.05). Donor CD34+CD38- cell number was significantly negatively associated with recipient engrafting CD34+CD45dimCD90+ cells/µl (r=-0.70, p = 0.05, n = 8).

Exercise might complement pharmacological mobilization by enhancing key HSC subgroups, improving collection quality, and supporting transplantation success; future research should evaluate combined approaches and the role of CRF in donor suitability and recipient outcomes.