心肌球源性干细胞在射血分数保留的心力衰竭治疗中的作用机制研究

Effect and mechanism of cardiosphere - derived cells in the treatment of heart failure with preserved ejection fraction in rats

目的探讨心肌球源性干细胞（Cardiosphere-derived cells,CDCs）在射血分数保留的心力衰竭（Heart failure with preserved ejection fraction,HFpEF）发生发展中的作用及机制.方法该研究使用的动物为DS大鼠.对72只DS大鼠采用0.3%氯化钠（低盐饮食）饮食喂养直至7周龄.每五只随机抽选一只共14只采用低盐饮食作为对照组,对余58只DS大鼠采用8%氯化钠饮食（高盐饮食）.当用高盐饮食喂养,DS大鼠出现向心性左心室肥厚及代偿舒张功能障碍时（6~7周）,根据单双号随机分成两组各29只,PBS（5%肝素,1%硝酸甘油）组接受PBS治疗,CDCs组接受CDCs治疗,采用心脏彩超检测各组左心室腔的大小及舒张功能,四周后对心肌进行天狼星红染色,分析心肌纤维化程度.结果PBS组E/A（A峰E峰流速比值）明显小于对照组和CDCs组[（1.20±0.30）比（1.70±0.20）和（1.80±0.16）,t=0.782、0.844,均P〈0.001],PBS组LAA（左房面积）明显大于对照组和CDCs组[（27.20±1.10）mm2比（19.80±0.76）mm2和（17.80±0.82）mm2,t=0.892、0.774,均P〈0.001];PBS组左心室内最大下降速度（-dp/dtmax）较对照组及CDCs组明显下降[（6.2±0.3）×103mmHg/s比（9.4±0.4）×103mmHg/s,t=0.382,P=0.024;（6.2±0.3）×103mmHg/s比（9.1±0.5）×103mmHg/s,t=0.883,P=0.022];PBS组左心室舒张末期压力（LVEDP）是CDCs组和对照组的两倍[（17±10）mmHg比（8±3）mmHg,t=0.922,P=0.003;（17±10）mmHg比（9±4）mmHg,t=0.903,P=0.004];Kaplan-Meier生存率分析可见CDCs组较PBS组明显延长（P=0.027）;PBS组肌成纤维细胞表达较对照组和CDCs组更明显（110/field比46/field,P〈0.001）;PBS组与对照组、CDCs组比较,多种炎性细胞因子的表达明显.结论CDCs通过减少炎性因子及纤维化,提高了HFpEF大鼠的生存率.

Objective To test whether cardiosphere-derived cells（CDCs）were sufficient to decrease manifestations of heart failure with preserved ejection fraction（HFpEF）in hypertensive rats.Methods DS rats（Charles River,Wilmington,Massachusetts）were fed 0.3% NaCl（low-salt）diet until 7 weeks of age.At that time,the diet was switched to an 8% NaCl（high-salt）diet in rats by random assignment.DS rats fed the low-salt diet constituted the control group（n=20）.At 13 to 14 weeks of age,rats with the high-salt diet were randomized to receive allogeneic rat CDCs or PBS.Echocardiography long-axis images of the left ventricular systolic and diastolic dimensions.Sirius red was used to assess fibrosis and proliferation.Results E/A ratio increased in the PBS-treated group compared with the control group and the CDCs-treated group [（1.20±0.30）vs.（1.70±0.20）or（1.80±0.16）,t=0.782,0.844,all P〈0.001].LAA kept increasing in the PBS-treated group[（27.20±1.10）mm2 vs.（19.80±0.76）mm2 or（17.80±0.82）mm2,t=0.892,0.774,all P〈0.001].The time constant of isovolumic LV pressure fall was prolonged in placebo-treated animals compared with CDCs-treated animals and control rats[（6.2±0.3）×103 mmHg/s vs.（9.4±0.4）×103 mmHg/s,t=0.382,P=0.024;（6.2±0.3）×103 mmHg/s vs.（9.1±0.5）×103 mmHg/s,t=0.883,P=0.022].LVEDP was 2-fold higher in placebo-treated group than in CDC-treated and control animals[（17±10）mmHg vs.（8±3）mmHg,t=0.922,P=0.003;（17±10）mmHg vs.（9±4）mmHg,t=0.922,P=0.004].A dramatic improvement of survival was observed in CDC-treated rats（Kaplan-Meier survival curves）（P=0.027）.Cardiac myofibroblasts increased dramatically in PBS-treated（110/field vs.46/field,P〈0.001）.Inflammatory cytokines expression siginficantly increased in PBS-treated group.Conclusion CDCs improves survival in a rat model of HFpEF through reducing inflammation and fibrosis.