Hou Xuwei, Appleby Nancy, Fuentes Tania, Longo Lawrence D, Bailey Leonard L, Hasaniya Nahidh, Kearns-Jonker Mary
Department of Pathology and Human Anatomy, Loma Linda University School of Medicine, Loma Linda, CA, USA.
J Clin Exp Cardiolog. 2012 Oct 11;S6.
Laboratory large animal models are important for establishing the efficacy of stem cell therapies that may be translated into clinical use. The similarity of ovine and human cardiovascular systems provides an opportunity to use the sheep as a large animal model in which to optimize cell-based treatments for the heart. Recent clinical trials in humans using endogenous cardiovascular progenitor cells report significant improvement in cardiac function following stem cell-based therapy. To date, however, endogenous cardiovascular progenitor cells have not been isolated from the sheep heart.
Cardiovascular cells expressing SSEA-4, CD105 and c-kit were isolated by flow cytometry and cloned from the right atrium of neonatal sheep. The expression of GATA-4, c-kit, and Isl1 was identified by PCR in the cloned cells. Immunohistochemical staining was used to compare the number of SSEA-4 positive cells in the right auricle, right atrium, left ventricle and the apex of the heart of fetal, neonatal and adult sheep. The number of SSEA4+cells was also compared in fetal, pregnant and non-pregnant adult sheep.
Four distinct cardiac progenitor cell sub-populations were identified in sheep, including CD105+SSEA-4+c-kit+Isl1+GATA-4+cells, CD105+SSEA-4+c-kit+Isl1+GATA-4-cells, CD105+SSEA-4-c-kit-Isl1+GATA-4-cells, and CD105+SSEA-4-c-kit+Isl1+GATA-4-cells. Immunohistochemical staining for SSEA-4 showed that labeled cells were most abundant in the right atrium of fetal hearts where niches of progenitor cells could be identified.
We determined the phenotype and distribution of cardiac progenitor cells in the sheep heart. The availability of cloned endogenous cardiac progenitor cells from sheep will provide a valuable resource for optimizing the conditions for cardiac repair in the ovine model.
实验室大动物模型对于确立可能转化为临床应用的干细胞疗法的疗效至关重要。绵羊和人类心血管系统的相似性为将绵羊用作大动物模型提供了契机，借此可优化针对心脏的细胞治疗方法。近期在人类中使用内源性心血管祖细胞的临床试验报告称，基于干细胞的治疗后心脏功能有显著改善。然而，迄今为止，尚未从绵羊心脏中分离出内源性心血管祖细胞。
通过流式细胞术从新生绵羊右心房中分离出表达阶段特异性胚胎抗原-4（SSEA-4）、CD105和c-kit的心血管细胞并进行克隆。通过聚合酶链反应（PCR）在克隆细胞中鉴定GATA-4、c-kit和Isl1的表达。采用免疫组织化学染色比较胎儿、新生和成年绵羊右心耳、右心房、左心室及心脏尖部SSEA-4阳性细胞的数量。还比较了胎儿、怀孕和未怀孕成年绵羊中SSEA4+细胞的数量。
在绵羊中鉴定出四个不同的心脏祖细胞亚群，包括CD105+SSEA-4+c-kit+Isl1+GATA-4+细胞、CD105+SSEA-4+c-kit+Isl1+GATA-4-细胞、CD105+SSEA-4-c-kit-Isl1+GATA-4-细胞和CD105+SSEA-4-c-kit+Isl1+GATA-4-细胞。SSEA-4的免疫组织化学染色显示，标记细胞在胎儿心脏的右心房中最为丰富，在那里可以识别出祖细胞龛。
我们确定了绵羊心脏中心脏祖细胞的表型和分布。从绵羊中获得克隆的内源性心脏祖细胞将为优化绵羊模型中的心脏修复条件提供宝贵资源。
