Lu Jun, Xu Liwei, Zeng Zifeng, Xue Chuqing, Li Jiale, Chen Xiong, Zhou Pengyu, Lin Shaoyan, Liao Yuhui, Du Xianjin, Yang Ronghua, Zheng Shaoyi
Department of Cardiovascular Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
Molecular Diagnosis and Treatment Center for Infectious Diseases, Dermatology Hospital, Southern Medical University, Guangzhou, China.
Front Cell Dev Biol. 2021 Aug 31;9:733183. doi: 10.3389/fcell.2021.733183. eCollection 2021.
The adoption of hearts from donation after circulatory death (DCD) is a promising approach for the shortage of suitable organs in heart transplantation. However, DCD hearts suffer from serious ischemia/reperfusion injury (IRI). Recent studies demonstrate that nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome-mediated pyroptosis is a novel target to ameliorate myocardial IRI. Melatonin is shown to inhibit NLRP3 inflammasome-mediated pyroptosis. Therefore, this study is designed to verify the hypothesis that melatonin can protect the heart graft preserved with heart perfusion (EVHP) against myocardial IRI inhibiting NLRP3 inflammasome-mediated pyroptosis in a rat model of DCD.
Donor-heart rats were randomly divided into three groups: (1) Control group: non-DCD hearts were harvested from heart-beating rats and immediately preserved with allogenic blood-based perfusate at constant flow for 105 min in the normothermic EVHP system; (2) DCD-vehicle group; and (3) DCD-melatonin group: rats were subjected to the DCD procedure with 25 min of warm ischemia injury and preserved by the normothermic EVHP system for 105 min. Melatonin (200 μmol/L) or vehicle was perfused in the cardioplegia and throughout the whole EVHP period. Cardiac functional assessment was performed every 30 min during EVHP. The level of oxidative stress, inflammatory response, apoptosis, and NLRP3 inflammasome-mediated pyroptosis of heart grafts submitted to EVHP were evaluated.
Twenty five-minute warm ischemia injury resulted in a significant decrease in the developed pressure (DP), d/d , and d/d of left ventricular of the DCD hearts, while the treatment with melatonin significantly increased the DP, d/d of the left ventricular of DCD hearts compared with DCD-vehicle group. Furthermore, warm ischemia injury led to a significant increase in the level of oxidative stress, inflammatory response, apoptosis, and NLRP3 inflammasome-mediated pyroptosis in the hearts preserved with EVHP. However, melatonin added in the cardioplegia and throughout the EVHP period significantly attenuated the level of oxidative stress, inflammatory response, apoptosis, and NLRP3 inflammasome-mediated pyroptosis compared with DCD-vehicle group.
EVHP combined with melatonin post-conditioning attenuates myocardial IRI in DCD hearts by inhibiting NLRP3 inflammasome-mediated pyroptosis, which might expand the donor pool by the adoption of transplantable DCD hearts.
采用心死亡后器官捐献（DCD）的心脏是解决心脏移植中合适供体器官短缺问题的一种有前景的方法。然而，DCD心脏会遭受严重的缺血/再灌注损伤（IRI）。最近的研究表明，核苷酸结合寡聚化结构域样受体家族含pyrin结构域3（NLRP3）炎性小体介导的细胞焦亡是改善心肌IRI的一个新靶点。褪黑素被证明可抑制NLRP3炎性小体介导的细胞焦亡。因此，本研究旨在验证这一假说：在DCD大鼠模型中，褪黑素可通过抑制NLRP3炎性小体介导的细胞焦亡来保护经体外静脉温血灌注（EVHP）保存的心脏移植物免受心肌IRI损伤。
供体心脏大鼠被随机分为三组：（1）对照组：从心跳的大鼠中获取非DCD心脏，并在常温EVHP系统中用同种异体血基灌注液以恒定流量立即保存105分钟；（2）DCD-载体组；（3）DCD-褪黑素组：大鼠经历25分钟的热缺血损伤的DCD过程，并通过常温EVHP系统保存105分钟。在心脏停搏液中及整个EVHP期间灌注褪黑素（200μmol/L）或载体。在EVHP期间每隔30分钟进行心脏功能评估。评估接受EVHP的心脏移植物的氧化应激、炎症反应、细胞凋亡及NLRP3炎性小体介导的细胞焦亡水平。
25分钟的热缺血损伤导致DCD心脏左心室的发展压力（DP）、dP/dt和-dP/dt显著降低，而与DCD-载体组相比，褪黑素治疗显著增加了DCD心脏左心室的DP、dP/dt。此外，热缺血损伤导致经EVHP保存的心脏中氧化应激、炎症反应、细胞凋亡及NLRP3炎性小体介导的细胞焦亡水平显著升高。然而，与DCD-载体组相比，在心脏停搏液中及整个EVHP期间添加褪黑素显著减轻了氧化应激、炎症反应、细胞凋亡及NLRP3炎性小体介导的细胞焦亡水平。
EVHP联合褪黑素后处理通过抑制NLRP3炎性小体介导的细胞焦亡减轻DCD心脏的心肌IRI，这可能通过采用可移植的DCD心脏来扩大供体库。
