胚胎干细胞的心脏应用(英文)

Cardiac application of embryonic stem cells

心肌梗死期间死亡的心肌细胞将由没有收缩功能的疤痕组织替代,因而极可能引起心力衰竭。对治疗心衰来说,修复死亡或损伤的心肌以及改善心功能仍面临着极大挑战。干细胞移植已在近年来的实验中用于修复损失的心肌。本文总结了近期在心肌损伤动物中实施胚胎干细胞移植的实验结果,并着重介绍对这类特定细胞的研究进展。胚胎干细胞取源于早期哺乳类胚胎的胚芽细胞,属于多功能干细胞。这类细胞具有长期增殖而不分化的能力,或能够在培养过程中分化成包括心肌细胞在内的所有特殊体细胞。由于胚胎干细胞具有极大的增殖和分化为成熟组织的能力,它们可能成为一种潜在的很有实用价值的细胞来源,可用于对病态心脏的功能心肌再生的细胞治疗。新近的研究表明,在心肌梗死动物模型中,心肌内移植胚胎干细胞或由其分化成的心肌样细胞,能导致已损伤心肌的再生,并改善心脏功能。另外,在病毒性心肌炎小鼠中,静脉输入胚胎干细胞可明显提高生存率和减轻心肌损伤。有关人类胚胎干细胞在体外分化成心肌细胞以及这些细胞的特性,近来已有报道。然而,要在临床能应用人类胚胎干细胞或由其分化成的心肌细胞来治疗晚期心脏疾病,还必须越过大量的伦理、法律和科学上的障碍。

Cardiomyocytes deceased during myocardial infarction (MI) are replaced with non-contractile scar tissue, whichhas a great chance to cause heart failure. Repair of dead or injured myocardium and improvement of cardiac function remain aserious challenge for the therapy of heart failure. Recently, stem cells have been transplanted in experimental settings to re-place lost myocardium. This article summarizes the recent experimental findings on transplantation of embryonic stem cells(ESCs) and their derived cells in animals with myocardial injury and highlights the progresses in research of these particularcell types. Beneficial effects of cell transplantation with other cell types in injured hearts have been detailed in other reviews.ESCs are pluripotent cells derived from early mammalian embryos at the blasto-stage. These cells have the capacity for pro-longed undifferentiated proliferation or differentiation into all of specialized somatic cell types of the body in culture, includingcardiomyocytes. Be at ability of proliferation and differentiation to mature tissues, ESCs are a potential valuableresource for cell therapy targeting regeneration of functional myocardium in diseased hearts. In recent animal studies intramyo-cardial transplantation of ESCs or their differentiated cardiac-like cells regenerated injured myocardium and improved heartfunction in infarcted animal models. In addition, intravenous infusion of ESCs significantly increased the survival rate and at-tenuated myocardial injury in viral myocarditic mice. Development and characterization of cardiomyocytes in vitro from humanESCs have been reported recently. However, many ethical, political, and scientific barriers have to be overcome before clini-cal utilization of human ESCs and their differentiated cells for treating end-stage cardiac diseases.