From the Division of Trauma, Surgical Critical Care, Burns and Acute Care Surgery, Department of Surgery (T.W.C., D.J.P., W.J., K.N., J.K., J.L.W., B.P.E.), UC San Diego School of Medicine, San Diego; and Comparative Effectiveness and Clinical Outcomes Research Center (R.C.), Riverside University Health System, Loma Linda University School of Medicine, Riverside, California.
J Trauma Acute Care Surg. 2024 Mar 1;96(3):371-377. doi: 10.1097/TA.0000000000004176. Epub 2023 Nov 26.
Acute lung injury and subsequent resolution following severe injury are coordinated by a complex lung microenvironment that includes extracellular vesicles (EVs). We hypothesized that there is a heterogenous population of EVs recruited to the alveoli postinjury and that we could identify specific immune-relevant mediators expressed on bronchoalveolar lavage (BAL) EVs as candidate biomarkers of injury and injury resolution.
Mice underwent 30% TBSA burn injury and BAL fluid was collected 4 hours postinjury and compared with sham. Extracellular vesicles were purified and single vesicle flow cytometry (vFC) was performed using fluorescent antibodies to quantify the expression of specific cell surface markers on individual EVs. Next, we evaluated human BAL specimens from injured patients to establish translational relevance of the mouse vFC analysis. Human BAL was collected from intubated patients following trauma or burn injury, EVs were purified, then subjected to vFC analysis.
A diverse population of EVs were mobilized to the alveoli after burn injury in mice. Quantitative BAL vFC identified significant increases in macrophage-derived CD44+ EVs (preinjury, 10.8% vs. postinjury, 13%; p < 0.05) and decreases in IL-6 receptor alpha (CD126) EVs (preinjury, 19.3% vs. postinjury, 9.3%, p < 0.05). Bronchoalveolar lavage from injured patients also contained a heterogeneous population of EVs derived from myeloid cells, endothelium, and epithelium sources, with CD44+ EVs being highly detected.
Injury causes mobilization of a heterogeneous population of EVs to the alveoli in both animal models and injured patients. Defining EV release after injury will be critical in identifying diagnostic and therapeutic targets to limit postinjury acute lung injury.
严重损伤后急性肺损伤及随后的恢复是由包括细胞外囊泡（EVs）在内的复杂肺微环境协调的。我们假设损伤后有一个异质的 EV 群体募集到肺泡，并且我们可以鉴定出支气管肺泡灌洗液（BAL）EV 上表达的特定免疫相关介质作为损伤和损伤恢复的候选生物标志物。
小鼠接受 30%TBSA 烧伤损伤，在损伤后 4 小时收集 BAL 液，并与假手术组进行比较。细胞外囊泡被纯化，并用荧光抗体进行单细胞流式细胞术（vFC），以量化单个 EV 上特定细胞表面标志物的表达。接下来，我们评估了来自受伤患者的人 BAL 标本，以确定小鼠 vFC 分析的转化相关性。从创伤或烧伤后接受插管的患者中收集人 BAL，纯化 EV，然后进行 vFC 分析。
在小鼠烧伤损伤后，大量 EV 被募集到肺泡。定量 BAL vFC 鉴定出巨噬细胞衍生的 CD44+EV（损伤前，10.8%；损伤后，13%；p<0.05）和 IL-6 受体α（CD126）EV（损伤前，19.3%；损伤后，9.3%；p<0.05）显著增加。受伤患者的支气管肺泡灌洗液也含有来自髓样细胞、内皮细胞和上皮细胞来源的异质 EV 群体，其中 CD44+EV 高度检测到。
损伤导致动物模型和受伤患者的肺泡中异质 EV 群体的动员。确定损伤后 EV 的释放将对于确定诊断和治疗靶点以限制损伤后急性肺损伤至关重要。
