Background

Remote ischemic conditioning (RIC) by brief periods of limb ischemia and reperfusion protects against ischemia–reperfusion injury. We studied the cardioprotective role of extracellular vesicles (EV)s released into the circulation after RIC and EV accumulation in injured myocardium.

Methods

We used plasma from healthy human volunteers before and after RIC (pre-PLA and post-PLA) to evaluate the transferability of RIC. Pre- and post-RIC plasma samples were separated into an EV enriched fraction (pre-EV + and post-EV +) and an EV poor fraction (pre-EV- and post-EV-) by size exclusion chromatography. Small non-coding RNAs from pre-EV + and post-EV + were purified and profiled by NanoString Technology. Infarct size was compared in Sprague–Dawley rat hearts perfused with isolated plasma and fractions in a Langendorff model. In addition, fluorescently labeled EVs were used to assess homing in an in vivo rat model. (ClinicalTrials.gov, number: NCT03380663)

Results

Post-PLA reduced infarct size by 15% points compared with Pre-PLA (55 ± 4% (n = 7) vs 70 ± 6% (n = 8), p = 0.03). Post-EV + reduced infarct size by 16% points compared with pre-EV + (53 ± 15% (n = 13) vs 68 ± 12% (n = 14), p = 0.03). Post-EV- did not affect infarct size compared to pre-EV- (64 ± 3% (n = 15) and 68 ± 10% (n = 16), p > 0.99). Three miRNAs (miR-16-5p, miR-144-3p and miR-451a) that target the mTOR pathway were significantly up-regulated in the post-EV + group. Labelled EVs accumulated more intensely in the infarct area than in sham hearts.

Conclusion

Cardioprotection by RIC can be mediated by circulating EVs that accumulate in injured myocardium. The underlying mechanism involves modulation of EV miRNA that may promote cell survival during reperfusion.

中文翻译：

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远程缺血调节对心脏的保护作用可通过血浆转移，并通过细胞外小泡介导

背景

短暂的肢体缺血和再灌注引起的远程缺血调节（RIC）可防止缺血再灌注损伤。我们研究了RIC和EV在受损心肌中积累后释放到循环中的细胞外囊泡（EV）的心脏保护作用。

方法

我们在RIC之前和之后（PLA之前和PLA之后）使用了健康人类志愿者的血浆来评估RIC的可转移性。通过尺寸排阻色谱将RIC之前和之后的血浆样品分为EV富集部分（EV +之前和EV +之后）和EV贫乏部分（EV-之前和EV之后）。通过NanoString Technology纯化和分析来自EV +前和EV +后的小非编码RNA。在Sprague-Dawley大鼠心脏中，用Langendorff模型中的离体血浆和血浆部分进行灌注后，比较梗死面积。此外，荧光标记的电动汽车被用于评估体内大鼠模型中的归巢。（ClinicalTrials.gov，编号：NCT03380663）

结果

与PLA前相比，PLA后梗死面积减少了15％（55±4％（n  = 7）对70±6％（n  = 8），p  = 0.03）。与EV前相比，EV后+梗死面积减少了16％（53±15％（n  = 13）对68±12％（n  = 14），p  = 0.03）。与EV前相比，EV后对梗塞面积没有影响（64±3％（n  = 15）和68±10％（n  = 16），p  > 0.99）。在EV +后组中，靶向mTOR途径的三个miRNA（miR-16-5p，miR-144-3p和miR-451a）显着上调。标记的电动汽车在梗死区域的累积要比假手术的心脏更为强烈。

结论

RIC的心脏保护作用可以通过在受损心肌中积累的循环EV介导。潜在的机制涉及EV miRNA的调节，这可能会促进再灌注过程中的细胞存活。