Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
The Max Harry Weil Institute for Critical Care Research and Innovation, University of Michigan, Ann Arbor, MI, 48109, USA.
Sci Rep. 2024 Jun 7;14(1):13081. doi: 10.1038/s41598-024-63522-w.
Extracorporeal cardiopulmonary resuscitation (ECPR) is emerging as a feasible and effective rescue strategy for prolonged cardiac arrest (CA). However, prolonged total body ischemia and reperfusion can cause microvascular occlusion that prevents organ reperfusion and recovery of function. One hypothesized mechanism of microvascular "no-reflow" is leukocyte adhesion and formation of neutrophil extracellular traps. In this study we tested the hypothesis that a leukocyte filter (LF) or leukocyte modulation device (L-MOD) could reduce NETosis and improve recovery of heart and brain function in a swine model of prolonged cardiac arrest treated with ECPR. Thirty-six swine (45.5 ± 2.5 kg, evenly distributed sex) underwent 8 min of untreated ventricular fibrillation CA followed by 30 min of mechanical CPR with subsequent 8 h of ECPR. Two females were later excluded from analysis due to CPR complications. Swine were randomized to standard care (Control group), LF, or L-MOD at the onset of CPR. NET formation was quantified by serum dsDNA and citrullinated histone as well as immunofluorescence staining of the heart and brain for citrullinated histone in the microvasculature. Primary outcomes included recovery of cardiac function based on cardiac resuscitability score (CRS) and recovery of neurologic function based on the somatosensory evoked potential (SSEP) N20 cortical response. In this model of prolonged CA treated with ECPR we observed significant increases in serum biomarkers of NETosis and immunohistochemical evidence of microvascular NET formation in the heart and brain that were not reduced by LF or L-MOD therapy. Correspondingly, there were no significant differences in CRS and SSEP recovery between Control, LF, and L-MOD groups 8 h after ECPR onset (CRS = 3.1 ± 2.7, 3.7 ± 2.6, and 2.6 ± 2.6 respectively; p = 0.606; and SSEP = 27.9 ± 13.0%, 36.7 ± 10.5%, and 31.2 ± 9.8% respectively, p = 0.194). In this model of prolonged CA treated with ECPR, the use of LF or L-MOD therapy during ECPR did not reduce microvascular NETosis or improve recovery of myocardial or brain function. The causal relationship between microvascular NETosis, no-reflow, and recovery of organ function after prolonged cardiac arrest treated with ECPR requires further investigation.
体外心肺复苏（ECPR）作为一种可行且有效的延长心脏骤停（CA）抢救策略正在出现。然而，长时间的全身缺血再灌注可导致微血管闭塞，从而阻止器官再灌注和功能恢复。微血管“无复流”的一个假设机制是白细胞黏附和中性粒细胞胞外陷阱（NET）的形成。在这项研究中，我们检验了以下假设：在接受 ECPR 治疗的长时间心脏骤停猪模型中，白细胞过滤器（LF）或白细胞调节装置（L-MOD）可减少 NETosis 并改善心脏和大脑功能的恢复。36 头猪（45.5±2.5kg，性别均匀分布）经历了 8 分钟未经治疗的心室颤动 CA，随后进行 30 分钟机械心肺复苏，随后进行 8 小时 ECPR。由于 CPR 并发症，后来有 2 头雌性被排除在分析之外。猪在 CPR 开始时随机分为标准护理（对照组）、LF 或 L-MOD。通过血清 dsDNA 和瓜氨酸化组蛋白以及心脏和大脑中微脉管系统中瓜氨酸化组蛋白的免疫荧光染色来定量 NET 形成。主要结局包括基于心脏可复律评分（CRS）的心脏功能恢复和基于体感诱发电位（SSEP）N20 皮质反应的神经功能恢复。在接受 ECPR 治疗的这种长时间 CA 模型中，我们观察到血清 NETosis 生物标志物显著增加，心脏和大脑中的微血管 NET 形成的免疫组织化学证据增加，但 LF 或 L-MOD 治疗并未减少这些证据。相应地，在 ECPR 开始后 8 小时，对照组、LF 组和 L-MOD 组之间的 CRS 和 SSEP 恢复没有显著差异（CRS=3.1±2.7、3.7±2.6 和 2.6±2.6；p=0.606；SSEP=27.9±13.0%、36.7±10.5%和 31.2±9.8%；p=0.194）。在接受 ECPR 治疗的这种长时间 CA 模型中，在 ECPR 期间使用 LF 或 L-MOD 治疗并不能减少微血管 NETosis 或改善心肌或大脑功能的恢复。在接受 ECPR 治疗的长时间心脏骤停后，微血管 NETosis、无复流和器官功能恢复之间的因果关系需要进一步研究。
