Hematopoietic stem cells (HSCs) are the basis of bone marrow (BM) transplantation. Its clinical success depends on the efficient HSCs mobilization from BM to peripheral blood (PB) for leukapheresis and clinical harnessing. Although granulocyte-colony stimulating factor (G-CSF) is the “gold standard” to stimulate the HSCs trafficking to PB, AMD3100 has emerged as a well-tolerated pharmacological strategy without significant toxicity.

Evaluate the influence of AMD3100 and G-CSF on HSCs mobilization in BM to PB in BALB/c mice.

Forty-five BALB/c mice were distributed into 5 groups to receive pre-treatment with intraperitoneal (i.p.) injection of phosphate-buffered saline (PBS) solution (160 μl/i.p.) or G-CSF (200 μg/kg/i.p.) for 4 consecutive days. On day 5 (D5), mice were also injected with PBS or AMD3100 (5 mg/kg/i.p.). These mice were then grouped into PBS+PBS control group (CG, n = 9) PBS+G-CSF group (n = 9), PBS+AMD3100 group (n = 9), G-CSF+PBS group (n = 9) and G-CSF+AMD3100 group (n = 9). After 1 hour, BM and PB samples were subsequently collected. The mobilized CD45+ CD34+ HSCs were assessed ex vivo using Flow Cytometry. Statistical analyses were performed through GraphPad Prism (v.5) using the One-way ANOVA test with Tukey's post-test.

Mice of the PBS+AMD3100 group exhibited significant HSCs enrichment into the BM and mobilization to PB when compared to CG and to the PBS+G-CSF group (p =0.0002). Furthermore, it was observed that mice of the G-CSF+PBS group also exhibited a higher frequency of HSCs in BM and PB compared to CG and to the PBS+G-CSF group (p =0.0002). Interestingly, mice of the G-CSF+PBS group had a significant increase of HSCs in BM when compared to CG and to the PBS+G-CSF group (p =0.0002). In contrast, mice of the G-CSF+AMD3100 group had the highest rate of HSCs mobilization in PB when compared to CG and to the PBS+G-CSF group (p =0.0002). The pre-treatment with G-CSF for 4 consecutive days or just a single dose of AMD3100 on D5 induced a higher enrichment of HSCs in BM and PB. However, the combination of pre-treatment with G-CSF with a single dose of AMD3100 on D5 just induced the highest mobilization of HSCs in PB.

These data demonstrate that AMD3100 induces more rapid and robust mobilization of CD34+ HSCs in the BM and PB, unlike G-CSF, which acts in a dose-dependent manner.

FAPEAM, CAPES and CNPq.