Cord Blood Stem Cell Expansion Ex Vivo With Endothelial Progenitor Cells

描述（申请人提供）：骨髓移植是治疗遗传性或获得性血液形成缺陷患者的有效手段。然而，只有1/3的潜在受体能找到合适的供体移植物。人脐带血含有足够的造血干细胞（HSC）和祖细胞移植相关受体（甚至成人）。脐带血作为成人患者的供体移植物的更广泛使用的限制是，在受体不相关和/或HLA不匹配的情况下，脐带血单位可能不包含足够数量的HSC。鉴定扩增脐带血HSC的方法将具有重要的临床应用，并构成重要的商业市场。 我们最近已经确定了一个层次的人内皮祖细胞，存在于人类婴儿和成人的循环，也存在于人类动脉和静脉。在初步研究中，我们将脐带血HSC（通过流式细胞术富集的CD 34 + CD 38）与脐带血衍生的内皮祖细胞离体共培养7天（添加造血生长因子），并证明在亚致死照射的免疫缺陷小鼠的骨髓中人CD 45+细胞植入增加> 100倍。 在该1期资助中，我们的目标是1）在免疫缺陷小鼠中使用有限稀释分析实验确定人HSC的倍数扩增，以确定使用内皮祖细胞离体扩增HSC的可行性，以及2）还将确定HSC扩增是否可以在非接触共培养系统中发生。

DESCRIPTION (provided by applicant): Bone marrow transplantation is an effective means to treat patients with inherited or acquired defects in blood formation. However, only 1/3 of the potential recipients can find suitable donor grafts. Human umbilical cord blood contains sufficient hematopoietic stem (HSC) and progenitor cells to engraft related recipients (even adults). A limitation to more widespread use of cord blood as a donor graft for adult patients is that cord blood units may not contain sufficient numbers of HSC in situations where the recipient is unrelated and/or HLA mismatched. Identification of methods to expand cord blood HSC would have significant clinical applications and constitute a significant commercial market. We have recently identified a hierarchy of human endothelial progenitor cells that are present in the circulation of the human infant and adult and also reside in human arteries and veins. In preliminary studies, we have co-cultured umbilical cord blood HSC (CD34+CD38- enriched by flow cytometry) with cord blood-derived endothelial progenitor cells for 7 days ex vivo (with added hematopoietic growth factors) and demonstrated a > 100 fold increase in human CD45+ cell engraftment in the bone marrow of sublethally irradiated immunodeficient mice. In this Phase 1 grant we aim to 1) determine the fold expansion of human HSC using limiting dilution analysis experiments in immunodeficient mice to determine feasibility of using the endothelial progenitors to expand HSC ex vivo and 2) will also determine whether the HSC expansion can occur in a non-contact co-culture system.