MOREHOUSE CCRE PP1- ENDOTHELIAL PROGENITOR CELLS IN SICKLE CELL DISEASE

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 为了更好地了解镰状细胞疾病的血管病变，我们有兴趣测量镰状细胞疾病患者的EPC数量和功能，并确定慢性红细胞输注治疗是否纠正数量或功能异常。我们假设，与正常对照组相比，镰状细胞病患者的循环内皮祖细胞数量增加，这是由于造血生长因子水平的增加以及血管闭塞事件导致的持续血管损伤。虽然未输血的镰状细胞受试者中内皮祖细胞的数量可能增加，但我们推测它们将损害血管形成并增加氧化剂的产生。输血治疗，通过降低促红细胞生成素的产生，将减少镰状细胞受试者循环中的内皮祖细胞数量，并可能恢复内皮细胞的正常功能。 镰状细胞血管病变中的EPC生物学从未被研究过。在这个试点项目中，我们建议调查镰状细胞病患者是否存在EPC数量或功能异常。阐明这些关系将提高我们对这种疾病一些致残性并发症的病因的理解，并增强我们开发有针对性的治疗干预措施治疗和预防镰状细胞血管并发症的能力。 假设 1.镰状细胞病患者的循环内皮祖细胞和生长细胞数量将比正常对照组增多，并伴随着促红细胞生成素水平的升高。 2.与正常对照组相比，Hb SS患者的EPC血管生成减少。 3.与正常对照组相比，Hb SS患者的EPC具有促氧化表型。 4.与未输血的镰状细胞病患者相比，接受红细胞输注治疗的镰状细胞病患者的红细胞生成素水平降低，循环内皮祖细胞和生长细胞数量减少，血管形成更好，氧化剂表达减少。 具体目标 1.定量检测三组受试者外周血中分离出的循环内皮祖细胞的数量：正常组、非慢性输血组和慢性输血组。 2.定量检测三组内皮祖细胞分化出的细胞数量及其衰老率。 3.检测三组受试者内皮祖细胞的血管形成情况。 4.测定三组内皮祖细胞内活性氧含量、超氧化物歧化水平和黄嘌呤氧化酶活性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. To better understand the vasculopathy of sickle cell disease, we are interested in measuring EPC number and function in people with sickle cell disease and determining whether chronic erythrocyte transfusion therapy corrects abnormalities in number or function. We hypothesize that the number of circulating EPCs are increased in individuals with sickle cell disease relative to normal controls due to increased levels of hematopoietic growth factors and ongoing vessel injury due to vaso-occlusive events. While numbers of EPCs in untransfused sickle cell subjects are likely to be increased, we postulate that they will have impaired vascular tube formation and increased oxidant production. Transfusion therapy, by lowering erythropoietin production, will lower the numbers of circulating EPCs in sickle cell subjects and may restore normal function to EPCs. EPC biology in sickle cell vasculopathy has never been studied. In this pilot project, we propose to investigate whether people with sickle cell disease have abnormal EPC number or function. Elucidation of these relationships will improve our understanding of the etiology of some of the disabling complications of this disease and enhance our ability to develop targeted therapeutic interventions for treatment and prevention of sickle cell vascular complications. HYPOTHESES 1. Individuals with sickle cell disease will have increased numbers of circulating EPCs and outgrowth cells than normal controls, in association with elevated levels of erythropoietin. 2. EPCs from subjects with Hb SS will have reduced vascular tube formation than those from normal controls. 3. EPCs from subjects with Hb SS will have a pro-oxidant phenotype compared to normal controls. 4. Subjects with sickle cell disease receiving red cell transfusion therapy will have reduced erythropoietin levels, lower numbers of circulating EPCs and outgrowth cells, better vascular tube formation and reduced oxidant expression than untransfused sickle cell subjects. SPECIFIC AIMS 1. Quantitate the number of circulating EPCs isolated from the peripheral blood of three groups of subjects: Hemoglobin AA (normal), hemoglobin SS without chronic transfusions, and hemoglobin SS on chronic transfusions. 2. Quantitate the number of outgrowth cells derived from EPCs and their rates of senescence in the three groups. 3. Measure vascular tube formation of EPCs from subjects in the three groups. 4. Measure intracellular reactive oxygen species, superoxide levels, and xanthine oxidase activity in the EPCs from the three groups.