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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。
Myocardial cells that die during a myocardial infarct will be replaced by non-contracting scar tissue, which is highly likely to cause heart failure. For the treatment of heart failure, the repair of dead or injured myocardium and improvement of cardiac function are still faced with great challenges. Stem cell transplantation has been used in recent years to repair damaged cardiac muscle. This article summarizes recent experimental results of embryonic stem cell transplantation in myocardial injury animals and highlights the progress made in this type of cell. Embryonic stem cells derived from early embryos of mammalian embryo cells, are pluripotent stem cells. Such cells have the ability to proliferate for long periods without differentiation or can differentiate into all specialized somatic cells including cardiomyocytes during culture. Due to their great ability to proliferate and differentiate into mature tissue, embryonic stem cells may become a potentially useful source of cells for the treatment of functional cardiac myocytes regenerated from diseased heart. Recent studies have shown that in an animal model of myocardial infarction, transplantation of embryonic stem cells or their differentiated cardiomyocytes into the myocardium results in the regeneration of damaged myocardium and improves cardiac function. In addition, in viral myocarditis mice, intravenous infusion of embryonic stem cells can significantly improve the survival rate and reduce myocardial damage. Recently, it has been reported that human embryonic stem cells differentiate into cardiomyocytes in vitro and the characteristics of these cells. However, the clinical application of human embryonic stem cells or cardiomyocytes differentiated from them to the treatment of advanced heart disease must also overcome a number of ethical, legal and scientific barriers.