Granulocyte Colony-stimulating Factor-mobilized CD34 Research Articles

Local Transplantation of Granulocyte Colony Stimulating Factor-Mobilized CD34+ Cells for Patients With Femoral and Tibial Nonunion: Pilot Clinical Trial

Most bone fractures typically heal, although a significant proportion (5%-10%) of fractures fail to heal, resulting in delayed union or persistent nonunion. Some preclinical evidence shows the therapeutic potential of peripheral blood CD34(+) cells, a hematopoietic/endothelial progenitor cell-enriched population, for bone fracture healing; however, clinical outcome following transplantation of CD34(+) cells in patients with fracture has never been reported. We report a phase I/IIa clinical trial regarding transplantation of autologous, granulocyte colony stimulating factor-mobilized CD34(+) cells with atelocollagen scaffold for patients with femoral or tibial fracture nonunion (n = 7). The primary endpoint of this study is radiological fracture healing (union) by evaluating anteroposterior and lateral views at week 12 following cell therapy. For the safety evaluation, incidence, severity, and outcome of all adverse events were recorded. Radiological fracture healing at week 12 was achieved in five of seven cases (71.4%), which was greater than the threshold (18.1%) predefined by the historical outcome of the standard of care. The interval between cell transplantation and union, the secondary endpoint, was 12.6 ± 5.4 weeks (range, 8-24 weeks) for clinical healing and 16.1 ± 10.2 weeks (range, 8-36 weeks) for radiological healing. Neither deaths nor life-threatening adverse events were observed during the 1-year follow-up after the cell therapy. These results suggest feasibility, safety, and potential effectiveness of CD34(+) cell therapy in patients with nonunion.

Long-term clinical outcome after intramuscular transplantation of granulocyte colony stimulating factor-mobilized CD34 positive cells in patients with critical limb ischemia

BackgroundOur phase I/IIa clinical trial revealed that intramuscular transplantation of autologous, GCSF-mobilized CD34+ cells was safe, feasible and potentially effective at week 4 and 12 post cellular therapy in 17 patients with chronic critical limb ischemia (CLI) (5 patients with atherosclerotic peripheral arterial disease (PAD) and 12 with Buerger's disease). However, long-term outcome of the cell therapy has yet to be reported. Methods and resultsIncidence of major clinical events and physiological parameters of limb ischemia were evaluated at week 52, 104, 156 and 208 post CD34+ cell therapy. No patients died by week 104, whereas 3 patients with PAD died by week 156 and 1 patient with Buerger's disease died by week 208 due to cardiac complications. No patients underwent major amputation, whereas 1 patient with Buerger's disease underwent unplanned minor amputation by week 104. CLI-free ratio was 88.2% at week 52 and 104, 92.3% at week 156 and 84.6% at week 208 in all patients. Significant improvement of toe brachial pressure index versus baseline was sustained up to week 208 and that of transcutaneous partial oxygen pressure was kept up to week 156. The Wong-Baker FACES pain rating scale, ulcer size and exercise tolerance significantly improved at week 52, the final evaluation time point, compared with baseline. Subgroup analysis revealed the similar outcome in patients with Buerger's disease. ConclusionsFavorable clinical outcomes as well as physiological evidences strongly indicate the long-term benefit of GCSF-mobilized CD34+ cell transplantation for retrieval from CLI, especially in patients with Buerger's disease.

Impact of constitutional polymorphisms in VCAM1 and CD44 on CD34+ cell collection yield after administration of granulocyte colony-stimulating factor to healthy donors

Background The number of CD34(+) cells mobilized from bone marrow to peripheral blood after administration of granulocyte colony-stimulating factor varies greatly among healthy donors. This fact might be explained, at least in part, by constitutional differences in genes involved in the interactions tethering CD34(+) cells to the bone marrow. We analyzed genetic characteristics associated with CD34(+) cell mobilization in 112 healthy individuals receiving granulocyte colony-stimulating factor (filgrastim; 10 μg/kg; 5 days). Genetic variants in VCAM1 and in CD44 were associated with the number of CD34(+) cells in peripheral blood after granulocyte colony-stimulating factor administration (P = 0.02 and P = 0.04, respectively), with the quantity of CD34(+) cells ×10⁶/kg of donor (4.6 versus 6.3; P < 0.001 and 7 versus 5.6; P = 0.025, respectively), and with total CD34(+) cells ×10⁶ (355 versus 495; P = 0.002 and 522 versus 422; P = 0.012, respectively) in the first apheresis. Of note, granulocyte colony-stimulating factor administration was associated with complete disappearance of VCAM1 mRNA expression in peripheral blood. Moreover, genetic variants in granulocyte colony-stimulating factor receptor (CSF3R) and in CXCL12 were associated with a lower and higher number of granulocyte colony-stimulating factor-mobilized CD34(+) cells/μL in peripheral blood (81 versus 106; P = 0.002 and 165 versus 98; P=0.02, respectively) and a genetic variant in CXCR4 was associated with a lower quantity of CD34(+) cells ×10⁶/kg of donor and total CD34(+) cells ×10⁶ (5.3 versus 6.7; P = 0.02 and 399 versus 533; P = 0.01, respectively). Conclusions In conclusion, genetic variability in molecules involved in migration and homing of CD34(+) cells influences the degree of mobilization of these cells.

The hypoxia-inducible factor is stabilized in circulating hematopoietic stem cells under normoxic conditions

The hypoxia-inducible factor (HIF) transcriptional system enables cell adaptation to limited O 2 availability, transducing this signal into patho-physiological responses such as angiogenesis, erythropoiesis, vasomotor control, and altered energy metabolism, as well as cell survival decisions. However, other factors beyond hypoxia are known to activate this pleiotropic transcription factor. The aim of this study was to characterize HIF in human hematopoietic stem cells (HSCs) and evidence is provided that granulocyte colony stimulating factor-mobilized CD34+- and CD133+-HSCs express a stabilized cytoplasmic form of HIF-1α under normoxic conditions. It is shown that HIF-1α stabilization correlates with down-regulation of the tumour suppressor von Hippel-Lindau protein (pVHL) and is positively controlled by NADPH-oxidase-dependent production of reactive oxygen species, indicating a specific O 2-independent post-transcriptional control of HIF in mobilized HSCs. This novel finding is discussed in the context of the proposed role of HIF as a mediator of progenitor cell recruitment to injured ischemic tissues and/or in the control of the maintenance of the undifferentiated state.

Large-scale culture and selective maturation of human Langerhans cells from granulocyte colony-stimulating factor-mobilized CD34+ progenitors.

Dendritic cells (DCs) play a critical role as APCs in the induction of the primary immune response. Their capacity for Ag processing and presentation is tightly regulated, controlled by a terminal developmental sequence accompanied by striking changes in morphology, organization, and function. The maturation process, which converts DCs from cells adapted for Ag accumulation to cells adapted for T cell stimulation, remains poorly understood due in part to difficulties in the culture and manipulation of DCs of defined lineages. To address these issues, we have devised conditions for the culture of a single DC type, Langerhans cells (LCs), using CD34+ cells from G-CSF-mobilized patients. Homogenous populations of LCs, replete with abundant immunocytochemically demonstrable Birbeck granules, could be stably maintained as immature DCs for long periods in culture. Unlike other human DC preparations, the LCs remained fully differentiated after cytokine removal. Following exposure to TNF-alpha, LPS, or CD40 ligand, the LCs could be synchronously induced to mature. Depending on the agent used, distinct types of LCs emerged differing in their capacity for T cell stimulation, IL-12 production, intracellular localization of MHC products, and overall morphology. Most interestingly, the expression of different sets of Toll family receptors is induced or down-regulated according to the maturation stimulus provided. These results strongly suggest that different proinflammatory stimuli might drive distinct developmental events.