Brunner Stefan, Zaruba Marc-Michael, Huber Bruno, David Robert, Vallaster Marcus, Assmann Gerald, Mueller-Hoecker Josef, Franz Wolfgang-Michael
Ludwig-Maximilians University, Klinikum Grosshadern, Medical Department I, Munich, Germany.
Exp Hematol. 2008 Sep;36(9):1157-66. doi: 10.1016/j.exphem.2008.03.014. Epub 2008 May 27.
Cytokine-mediated mobilization of hematopoietic stem cells has become an established method in the field of autologous and allogenic stem cell transplantation. Furthermore, it presents a new concept in tissue repair and regenerative medicine. In the present study, we explored the potency of parathyroid hormone (PTH) compared to granulocyte colony-stimulating factor (G-CSF) for mobilization of stem cells and its regenerative capacity on bone marrow.
Healthy mice were either treated with PTH, G-CSF, or saline. Laboratory parameters were analyzed using a hematological cell analyzer. Hematopoietic stem cells characterized by lin(-)/Sca-1(+)/c-kit(+), as well as subpopulations (CD31(+), c-kit(+), Sca-1(+), CXCR4(+)) of CD45(+)/CD34(+) and CD45(+)/CD34(-) cells were measured by flow cytometry. Immunohistology as well as fluorescein-activated cell sorting analyses were utilized to determine the composition and cell-cycle status of bone marrow cells. Serum levels of distinct cytokines (G-CSF, vascular endothelial growth factor [VEGF]) were determined by enzyme-linked immunosorbent assay. Further, circulating cells were measured after PTH treatment in combination with G-CSF or a G-CSF antibody.
Stimulation with PTH showed a significant increase of all characterized subpopulations of bone marrow-derived progenitor cells (BMCs) in peripheral blood (1.5- to 9.8-fold) similar to G-CSF. In contrast to G-CSF, PTH treatment resulted in an enhanced cell proliferation with a constant level of lin(-)/Sca-1(+)/c-kit(+) cells and CD45(+)/CD34(+) subpopulations in bone marrow. Interestingly, PTH application was associated with increased serum levels of G-CSF (2.8-fold), whereas VEGF showed no significant changes. Blocking endogenous G-CSF with an antibody significantly reduced the number of circulating cells after PTH treatment. A combination of PTH and G-CSF showed slight additional effects compared to PTH or G-CSF alone.
PTH induces mobilization of progenitor cells effectively, which can be related to an endogenous release of G-CSF. In contrast to G-CSF treatment, PTH does not result in a depletion of bone marrow, which may be mediated by an activation of PTH receptor on osteoblasts. The novel function of PTH on mobilization and regeneration of BMCs may pave the way for new therapeutic options in bone marrow and stem cell transplantation as well as in the field of ischemic disorders.
细胞因子介导的造血干细胞动员已成为自体和异体干细胞移植领域的一种成熟方法。此外，它在组织修复和再生医学中提出了一个新概念。在本研究中，我们探讨了甲状旁腺激素（PTH）与粒细胞集落刺激因子（G-CSF）相比在干细胞动员方面的效力及其对骨髓的再生能力。
将健康小鼠分别用PTH、G-CSF或生理盐水处理。使用血液学细胞分析仪分析实验室参数。通过流式细胞术测量以lin(-)/Sca-1(+)/c-kit(+)为特征的造血干细胞，以及CD45(+)/CD34(+)和CD45(+)/CD34(-)细胞的亚群（CD31(+)、c-kit(+)、Sca-1(+)、CXCR4(+)）。利用免疫组织学以及荧光激活细胞分选分析来确定骨髓细胞的组成和细胞周期状态。通过酶联免疫吸附测定法测定不同细胞因子（G-CSF、血管内皮生长因子 [VEGF]）的血清水平。此外，在PTH与G-CSF或G-CSF抗体联合处理后测量循环细胞。
与G-CSF相似，PTH刺激使外周血中所有特征性的骨髓来源祖细胞（BMC）亚群显著增加（1.5至9.8倍）。与G-CSF不同，PTH处理导致细胞增殖增强，骨髓中lin(-)/Sca-1(+)/c-kit(+)细胞和CD45(+)/CD34(+)亚群水平保持恒定。有趣的是，应用PTH与血清G-CSF水平升高（2.8倍）相关，而VEGF无显著变化。用抗体阻断内源性G-CSF可显著减少PTH处理后的循环细胞数量。与单独使用PTH或G-CSF相比，PTH与G-CSF联合使用显示出轻微的附加效应。
PTH可有效诱导祖细胞动员，这可能与内源性释放G-CSF有关。与G-CSF处理不同，PTH不会导致骨髓耗竭，这可能是由成骨细胞上PTH受体的激活介导的。PTH在BMC动员和再生方面的新功能可能为骨髓和干细胞移植以及缺血性疾病领域的新治疗选择铺平道路。
