Li Zongjin, Lee Andrew, Huang Mei, Chun Hyung, Chung Jaehoon, Chu Pauline, Hoyt Grant, Yang Phillip, Rosenberg Jarrett, Robbins Robert C, Wu Joseph C
Department of Radiology and Molecular Imaging Program (MIPS), Stanford University School of Medicine, Stanford, California 94305-5344, USA.
J Am Coll Cardiol. 2009 Apr 7;53(14):1229-40. doi: 10.1016/j.jacc.2008.12.036.
The goal of this study is to characterize resident cardiac stem cells (CSCs) and investigate their therapeutic efficacy in myocardial infarction by molecular imaging methods.
CSCs have been isolated and characterized in vitro. These cells offer a provocative method to regenerate the damaged myocardium. However, the survival kinetics and function of transplanted CSCs have not been fully elucidated.
CSCs were isolated from L2G85 transgenic mice (FVB strain background) that constitutively express both firefly luciferase and enhanced green fluorescence protein reporter gene. CSCs were characterized in vitro and transplanted in vivo into murine infarction models. Multimodality noninvasive imaging techniques were used to assess CSC survival and therapeutic efficacy for restoration of cardiac function.
CSCs can be isolated from L2G85 mice, and fluorescence-activated cell sorting analysis showed expression of resident CSC markers (Sca-1, c-Kit) and mesenchymal stem cell markers (CD90, CD106). Afterwards, 5 x 10(5) CSCs (n = 30) or phosphate-buffered saline control (n = 15) was injected into the hearts of syngeneic FVB mice undergoing left anterior descending artery ligation. Bioluminescence imaging showed poor donor cell survival by week 8. Echocardiogram, invasive hemodynamic pressure-volume analysis, positron emission tomography imaging with fluorine-18-fluorodeoxyglucose, and cardiac magnetic resonance imaging demonstrated no significant difference in cardiac contractility and viability between the CSC and control group. Finally, postmortem analysis confirmed transplanted CSCs integrated with host cardiomyocytes by immunohistology.
In a mouse myocardial infarction model, Sca-1-positive CSCs provide no long-term engraftment and benefit to cardiac function as determined by multimodality imaging.
本研究的目的是通过分子成像方法对心脏驻留干细胞（CSCs）进行表征，并研究其在心肌梗死中的治疗效果。
CSCs已在体外分离和表征。这些细胞为受损心肌的再生提供了一种有前景的方法。然而，移植的CSCs的存活动力学和功能尚未完全阐明。
从组成型表达萤火虫荧光素酶和增强型绿色荧光蛋白报告基因的L2G85转基因小鼠（FVB品系背景）中分离CSCs。在体外对CSCs进行表征，并将其体内移植到小鼠梗死模型中。使用多模态非侵入性成像技术评估CSCs的存活情况以及恢复心脏功能的治疗效果。
可从L2G85小鼠中分离出CSCs，荧光激活细胞分选分析显示其表达心脏驻留干细胞标志物（Sca-1、c-Kit）和间充质干细胞标志物（CD90、CD106）。之后，将5×10⁵个CSCs（n = 30）或磷酸盐缓冲盐水对照（n = 15）注射到接受左前降支动脉结扎的同基因FVB小鼠心脏中。生物发光成像显示到第8周时供体细胞存活情况不佳。超声心动图、有创血流动力学压力-容积分析、用氟-18-氟脱氧葡萄糖进行的正电子发射断层扫描成像以及心脏磁共振成像显示，CSC组和对照组在心脏收缩力和活力方面无显著差异。最后，尸检分析通过免疫组织学证实移植的CSCs与宿主心肌细胞整合。
在小鼠心肌梗死模型中，通过多模态成像确定，Sca-1阳性CSCs不能长期植入，对心脏功能也无益处。
