Factors Responsible for Cardiac Preservation Conferred by Adult Marrow Stem Cells

描述（由申请人提供）：称为间充质干细胞（MSC）的成人骨髓非造血干细胞促进心肌梗死（MI）动物的功能性心脏恢复。在几个国家，这些细胞已被用于MI患者，并报告了有益的效果。尽管MSC管理的功效，大多数研究表明，很少的细胞长期植入，只有一部分存活的细胞似乎分化为成熟的心脏表型。在动物中，将浓缩的条件培养基注射到心肌中似乎具有与直接注射细胞类似的效果，这意味着来自细胞的分泌因子构成益处的主要基础。我们的初步数据表明，非造血的人骨髓干细胞可以发挥心脏保护和修复作用时，提供静脉注射（IV）与心肌梗死的动物。此外，我们表明，无血清培养基条件的混合骨髓间充质干细胞或标准化的骨髓间充质干细胞分离的p75低亲和力神经生长因子受体（p75 LNGFR; p75骨髓间充质干细胞）可以支持成人心脏干/祖细胞的生长和生存，通过激活转录因子STAT 3。因为MSC是从粘附细胞的异质混合物制备的，所以期望具有用于祖细胞群的标准化分离程序，所述祖细胞群预测性地赋予心脏保护和/或修复。我们最近通过特异性细胞表面表位从骨髓单个核细胞中分离出非造血干细胞亚群。基于它们分泌蛋白的表达谱，它们可能特别适合于心脏保存。比较这些亚群之一（p75间充质干细胞）的混合贴壁间充质干细胞的有效性，我们将确定是否静脉或肌肉注射非自体干细胞可用于提供基于旁分泌的心脏细胞治疗。我们将确定由干细胞分泌的有效因子，并确定其作用机制是否是通过抑制凋亡或坏死或增加内源性心脏干细胞的增殖和存活来保留现有的心肌细胞。 具体目标 1.鉴定具有心脏保护作用的人骨髓干细胞亚群，并确定免疫缺陷小鼠MI后挽救心脏功能所需的生长条件和给药时间。 2.确定静脉或肌内输注品系不匹配的小鼠骨髓干细胞促进免疫活性小鼠心肌梗死后心脏保护或恢复的能力。 3.目的：鉴定干细胞分泌的保护心脏功能的特异性因子。

DESCRIPTION (provided by applicant): The adult bone marrow non-hematopoietic stem cells known as mesenchymal stem cells (MSCs) promote functional cardiac recovery in animals with myocardial infarction (MI). In several countries these cells have been administered to patients with MI with reported beneficial effects. Despite the efficacy of MSC administration, most studies have shown that few of the cells engraft long-term and that only a portion of the surviving cells appear to differentiate to a mature cardiac phenotype. In animals injection of concentrated conditioned medium into cardiac muscle appears to have effects similar to those of direct injection of cells, implying that secreted factors from the cells comprise the principle basis for the benefits. Our preliminary data demonstrate that non-hematopoietic human bone marrow stem cells can exert cardiac protective and reparative effects when delivered intravenously (IV) to animals with MI. Furthermore, we show that serum-free medium conditioned by mixed MSCs or by standardized MSCs isolated by magnetic sorting for the p75 low affinity nerve growth factor receptor (p75LNGFR; p75MSCs) can support the growth and survival of adult cardiac stem/progenitor cells through activation of the transcription factor STAT3. Because MSCs are prepared from a heterogeneous mixture of adherent cells, it is desirable to have a standardized isolation procedure for a population of progenitor cells that predictively imparts cardiac protection and/or repair. We have recently isolated sub-populations of non-hematopoietic stem cells from the total mononuclear cells of bone marrow by specific cell surface epitopes. They may be particularly well-suited for cardiac preservation based on their expression profiles of secreted proteins. Comparing the effectiveness of one of these sub-populations (p75MSCs) to mixed adherent MSCs, we will determine whether intravenous or intramuscular administration of non-autologous stem cells can be used to provide paracrine-based cardiac cell therapy. We will identify the factors secreted by the stem cells that are effective and determine whether the mechanism of action is sparing of existing cardiomyocytes by inhibition of apoptosis or necrosis or augmenting the proliferation and survival of endogenous cardiac stem cells. SPECIFIC AIMS 1. To identify a cardioprotective sub-population of human bone marrow stem cells and determine the growth conditions and timing of administration necessary to rescue cardiac function after MI in immunodeficient mice. 2. To determine the ability of strain-mismatched murine bone marrow stem cells delivered intravenously or intramuscularly to promote cardiac protection or recovery after MI in immunocompetent mice. 3. To identify the specific factors secreted by the stem cells that preserve cardiac function.