Biological Characterization of Cardiac Stem Cells

描述（由申请人提供）：我们已经证明，与年龄匹配的对照hCSC相比，来源于终末期心力衰竭（ESHF）心脏的人心脏干细胞（hCSC）在改善梗死后LV功能方面具有明显的上级优势。本申请的目的是表征ESHF衍生的hCSC性能改善的分子机制，并优化其收获、分子表征和在MI后心力衰竭临床相关模型中的应用。通过干细胞治疗改善ESHF患者的左室功能，特别是终末期心力衰竭儿童， 心脏移植是唯一可行的选择，而且供应有限。尽管它们的临床I期结果令人鼓舞，但由异质细胞类型（包括c-kit+细胞）组成的心球衍生细胞（CDC）仍然没有得到很好的表征1。我们的初步数据显示，从左心房分离的ESHF衍生的hCDC比从右心房分离的ESHF衍生的hCDC更好地改善缺血性左心室功能，但在所有其他心室衍生的hCDC中是否存在不同的功能活性仍是未知的。此外，由于我们记录了ESHF衍生的CDC内c-kit+细胞的数量显著较高，CDC内c-kit+细胞的频率可能对功能恢复至关重要。最后，ESHF衍生的CDC分泌更高水平的血管生成细胞因子，其与梗死心肌中血管生成的增加和更高水平的HIF-1a相关，但细胞因子分泌增加的机制尚不清楚。我们的假设是，ESHF衍生的hCDC改善心肌功能的效果取决于hCDC起源的解剖部位和c-kit+和HIF- 1a的分子机制。这些研究将通过确定以下内容来阐明hCDC的生物学和功能：1）hCDC之间的室特异性差异，其可能需要修饰以获得更强大的心肌功能活性，2）c-kit+细胞的频率对LV恢复的影响，以及最后，3）HIF-1 a作为ESHF衍生的hCDC的心肌功能的主要细胞因子调节剂的作用。ESHF患者，特别是儿童，可能是从基于hCDC的治疗中获益最多的患者。该应用是第一项旨在确定ESHF衍生的hCDC的关键特征并以最终可能影响未来治疗干预的方式揭示其功能活性的新机制的研究。

DESCRIPTION (provided by applicant): We have demonstrated that human cardiac stem cells (hCSC) derived from end-stage heart failure (ESHF) hearts are markedly superior in improving post-infarct LV function in comparison to age-match control hCSC. The goal of this application is to characterize the molecular mechanisms underlying this improved performance of ESHF-derived hCSC and to optimize their harvest, molecular characterization and application in a clinically-relevant model of post-MI cardiac failure. Improvement of LV function in ESHF patients, particularly children with end- stage heart failure, via stem cell therapy is of enormous importance since heart transplantation is the only other viable option and in limited supply. Despite their encouraging clinical Phase I results, cardiosphere derived cells (CDCs), comprised of heterogeneous cell types, including c- kit+ cells, are still not well characterized1. Our preliminary data shows that ESHF-derived hCDCs isolated from the left atrium improve ischemic left ventricular function better than ESHF-derived hCDCs from the right atrium, but whether different functional activity is present in all other heart chamber-derived hCDCs is still unknown. Furthermore, since we document significantly higher numbers of c-kit+ cells within ESHF-derived CDCs, the frequency of the c-kit+ cells within CDCs may be critical to recovery of function. Finally, ESHF-derived CDCs secrete higher levels of angiogenic cytokines that correlates with increased angiogenesis in the infarcted myocardium and higher levels of HIF-1a, but the mechanism for the increased cytokine secretion is unclear. Our hypothesis is that the effect of ESHF-derived hCDCs in improving myocardial function is dependent on the anatomic site of hCDC origin and molecular mechanisms by c-kit+ and HIF- 1a. These studies will clarify the biology and function of hCDCs by determining: 1) chamber specific differences amongst hCDCs with the potential need to modify for a more powerful myocardial functional activity, 2) the effect of the frequency of c-kit+ cells on LV recovery, and lastly, 3) the role of HIF-1a as a master cytokine regulator of the myocardial function of ESHF- derived hCDCs. ESHF patients, particularly children, are potentially the most to benefit from hCDC based therapies. This application is the first study designed to determine critical characteristics of ESHF-derived hCDCs and to uncover new mechanisms of their functional activity in a manner that may eventually influence future therapeutic interventions.