人脐血间充质干细胞向成心肌细胞诱导扩增后的生物安全性评价

Biological security of differentiation of human umbilical cord blood-derived mesenchymal stem cells into cardiomyocytes

背景:人脐血间充质干细胞在体外分离培养并向心肌细胞诱导分化的条件下,能否仍然维持原有的正常生理性状态,即是否达到种子细胞的生物安全性标准,目前尚少见研究。目的:分析人脐血间充质干细胞在体外分离培养及向心肌细胞诱导分化的条件下,其染色体核型及端粒酶活性是否发生异常的改变及细胞是否产生致肿瘤性。方法:采用染色体G显带处理方法体外分离、培养的第3代以后的人脐血间充质干细胞和向心肌细胞诱导培养至第7代后的样本进行核型分析,分析细胞的端粒酶活性,细胞周期相关基因cyclinA、cdk2、C-fos、h-TERT、c-myc和p53的表达,并通过裸鼠皮下致肿瘤试验对细胞的致肿瘤性进行分析。结果与结论:人脐血间充质干细胞和向心肌细胞诱导体外培养至第7代,未发现染色体核型异常改变,相应的端粒酶活性也未出现异常增高。c-myc、p53、h-TERT、C-fos无表达。致肿瘤试验,实验裸鼠在观察期内均未见结节形成或可疑病灶产生,符合国家医疗产品生物学评价标准的要求。

BACKGROUND：Under the differentiation into cardiomyocytes in vitro,few studies have addressed whether human umbilical cord blood-derived mesenchymal stem cells（UCB-derived MSCs） can maintain their normal physiological properties.i.e.whether reach the biological safety standards of seed cells.OBJECTIVE：To analyze the changes of chromosome karyotype,telomerase activity and tumorigenicity under a condition of cardiomyocyte differentiated from human UCB-derived MSCs that were isolated and cultured in vitro.METHODS：Karyotypes were analyzed in UCB-derived MSCs from the third passage that was isolated and cultured in vitro using chromosome G-banding technique and samples following the seventh passage of cells differentiating into cardiomyocytes.Cell telomerase activity and cell cycle-related genes cyclinA,cdk2,C-fos,h-TERT,c-myc and p53 expression were analyzed.The nude mice carcinogenic test was performed to test the tumorigenicity of cells.RESULTS AND CONCLUSION：No abnormal changes in the chromosome karyotype and telomerase activity were detected in human UCB-derived MSCs following in vitro cardiomyocyte culture up to the seventh passage.There were no c-myc,p53,h-TERT and C-fos expressions in tested cells.Any abnormal changes such as skin nodules or doubtful focus in the nude mice could not be found.These are consistent with the National Medical Product Biology Evaluation Criterion.