Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University (J.L., Y.L., Y.L., Z.W.).
Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh (J.L., Y.L., K.H., Y.L., Z.W., H.J.L., K.D.P., P.-U.C.D.).
Circulation. 2024 Aug 27;150(9):710-723. doi: 10.1161/CIRCULATIONAHA.123.065005. Epub 2024 Aug 26.
Exosome therapy shows potential for cardiac repair after injury. However, intrinsic challenges such as short half-life and lack of clear targets hinder the clinical feasibility. Here, we report a noninvasive and repeatable method for exosome delivery through inhalation after myocardial infarction (MI), which we called stem cell-derived exosome nebulization therapy (SCENT).
Stem cell-derived exosomes were characterized for size distribution and surface markers. C57BL/6 mice with MI model received exosome inhalation treatment through a nebulizer for 7 consecutive days. Echocardiographies were performed to monitor cardiac function after SCENT, and histological analysis helped with the investigation of myocardial repair. Single-cell RNA sequencing of the whole heart was performed to explore the mechanism of action by SCENT. Last, the feasibility, efficacy, and general safety of SCENT were demonstrated in a swine model of MI, facilitated by 3-dimensional cardiac magnetic resonance imaging.
Recruitment of exosomes to the ischemic heart after SCENT was detected by ex vivo IVIS imaging and fluorescence microscopy. In a mouse model of MI, SCENT ameliorated cardiac repair by improving left ventricular function, reducing fibrotic tissue, and promoting cardiomyocyte proliferation. Mechanistic studies using single-cell RNA sequencing of mouse heart after SCENT revealed a downregulation of in endothelial cells (ECs). In an EC- conditional knockout mouse model, the inhibition of CD36, a fatty acid transporter in ECs, led to a compensatory increase in glucose utilization in the heart and higher ATP generation, which enhanced cardiac contractility. In pigs, cardiac magnetic resonance imaging showed an enhanced ejection fraction (Δ=11.66±5.12%) and fractional shortening (Δ=5.72±2.29%) at day 28 after MI by SCENT treatment compared with controls, along with reduced infarct size and thickened ventricular wall.
In both rodent and swine models, our data proved the feasibility, efficacy, and general safety of SCENT treatment against acute MI injury, laying the groundwork for clinical investigation. Moreover, the EC- mouse model provides the first in vivo evidence showing that conditional EC-CD36 knockout can ameliorate cardiac injury. Our study introduces a noninvasive treatment option for heart disease and identifies new potential therapeutic targets.
外泌体疗法在损伤后显示出心脏修复的潜力。然而，半衰期短和缺乏明确靶点等内在挑战阻碍了其临床可行性。在这里，我们报告了一种通过心肌梗死（MI）后吸入实现外泌体递送的非侵入性和可重复的方法，我们称之为干细胞衍生的外泌体雾化治疗（SCENT）。
对干细胞衍生的外泌体进行大小分布和表面标志物的特征分析。MI 模型的 C57BL/6 小鼠通过雾化器连续 7 天接受外泌体吸入治疗。在 SCENT 后进行超声心动图监测心功能，组织学分析有助于研究心肌修复。通过单细胞 RNA 测序对整个心脏进行分析，以探讨 SCENT 的作用机制。最后，通过 3 维心脏磁共振成像在 MI 的猪模型中证明了 SCENT 的可行性、疗效和一般安全性。
通过体外 IVIS 成像和荧光显微镜检测到 SCENT 后外泌体募集到缺血性心脏。在 MI 的小鼠模型中，SCENT 通过改善左心室功能、减少纤维组织和促进心肌细胞增殖来改善心脏修复。SCENT 后对小鼠心脏进行单细胞 RNA 测序的机制研究表明内皮细胞（ECs）中的下调。在 EC 条件性敲除小鼠模型中，抑制 EC 中的脂肪酸转运蛋白 CD36 导致心脏中葡萄糖利用的代偿性增加和更高的 ATP 生成，从而增强了心脏收缩力。在猪中，与对照组相比，SCENT 治疗在 MI 后第 28 天通过心脏磁共振成像显示出射血分数（Δ=11.66±5.12%）和缩短分数（Δ=5.72±2.29%）的提高，同时减少了梗死面积和心室壁增厚。
在啮齿动物和猪模型中，我们的数据证明了 SCENT 治疗急性 MI 损伤的可行性、疗效和一般安全性，为临床研究奠定了基础。此外，EC 小鼠模型提供了第一个体内证据，表明条件性 EC-CD36 敲除可以改善心脏损伤。我们的研究为心脏病提供了一种非侵入性治疗选择，并确定了新的潜在治疗靶点。
