背景:心脏代谢在心力衰竭和缺血再灌注损伤状态下发生改变。我们假设心脏移植(HT)前非原位常温灌注期间的代谢组学分析将有助于深入了解心肌底物的利用,并报告亚临床和临床同种异体移植功能障碍的风险。
方法:对一系列非原位常温灌注液样品进行代谢组学分析,分析乳酸和心肌肌钙蛋白I(TnI)以及代谢物(66酰基肉碱,15个氨基酸,非酯化脂肪酸[NEFA],酮,和3-羟基丁酸酯)。我们测试了损伤生物标志物和代谢物随时间的变化,以及恢复策略的差异变化(循环系统死亡后的捐赠[DCD]与脑死亡后的捐赠[DBD])。我们检查了代谢物之间的关联,损伤生物标志物,和原发性移植物功能障碍(PGD)。使用针对恢复策略调整的线性混合模型进行分析,分析批次,捐赠者预测的心脏质量,和时间。
结果:来自92次非原位灌注运行的总共176个样本来自供体,平均年龄为35(标准偏差11.3)岁,中位总非原位灌注时间为234(四分位距84)分钟。随着时间的推移,乳酸趋势因恢复策略而异,而无论DCD和DBD状态如何,TnI在非原位灌注期间都会增加。我们发现燃料底物在非原位灌注过程中迅速耗尽,最值得注意的是支链氨基酸亮氨酸/异亮氨酸,以及酮,3-羟基丁酸酯,和NEFA(最小二乘[LS]平均从第一个到最后一个时间点的差异-1.7到-4.5,错误发现率q<0.001)。几种长链酰基肉碱(LCAC),包括C16,C18,C18:1,C18:2,C18:3,C20:3和C20:4,在灌注运行期间增加(LS平均差0.42-0.67,q<0.001)。许多LCAC与乳酸和TnI密切相关。DCD与DBD的许多LCAC随时间的变化显着不同,提示缺血性损伤模式对燃料底物利用的不同趋势。亮氨酸/异亮氨酸的变化,精氨酸C12:1-OH/C10:1-DC,和C16-OH/C14-DC与中重度PGD的几率增加相关。运行结束或乳酸或TnI的变化均与PGD无关。
结论:非原位常温灌注溶液的代谢组学分析揭示了与亚临床和临床同种异体移植功能障碍相关的燃料底物利用模式。这项研究强调了在异位灌注期间同种异体移植预处理中专注于燃料底物修饰的干预措施的潜在作用,以改善同种异体移植的结果。
BACKGROUND: Cardiac metabolism is altered in heart failure and ischemia-reperfusion injury states. We hypothesized that metabolomic profiling during ex situ normothermic perfusion before heart transplantation (HT) would lend insight into myocardial substrate utilization and report on subclinical and clinical allograft dysfunction risk.
METHODS: Metabolomic profiling was performed on serial samples of ex situ normothermic perfusate assaying biomarkers of myocardial injury in lactate and cardiac troponin I (TnI) as well as metabolites (66 acylcarnitines, 15 amino acids, nonesterified fatty acids [NEFA], ketones, and 3-hydroxybutyrate). We tested for change over time in injury biomarkers and metabolites, along with differential changes by recovery strategy (donation after circulatory death [DCD] vs donation after brain death [DBD]). We examined associations between metabolites, injury biomarkers, and primary graft dysfunction (PGD). Analyses were performed using linear mixed models adjusted for recovery strategy, assay batch, donor-predicted heart mass, and time.
RESULTS: A total of 176 samples from 92 ex situ perfusion runs were taken from donors with a mean age of 35 (standard deviation 11.3) years and a median total ex situ perfusion time of 234 (interquartile range 84) minutes. Lactate trends over time differed significantly by recovery strategy, while TnI increased during ex situ perfusion regardless of DCD vs DBD status. We found fuel substrates were rapidly depleted during ex situ perfusion, most notably the branched-chain amino acids leucine/isoleucine, as well as ketones, 3-hydroxybutyrate, and NEFA (least squares [LS] mean difference from the first to last time point -1.7 to -4.5, false discovery rate q < 0.001). Several long-chain acylcarnitines (LCAC), including C16, C18, C18:1, C18:2, C18:3, C20:3, and C20:4, increased during the perfusion run (LS mean difference 0.42-0.67, q < 0.001). Many LCACs were strongly associated with lactate and TnI. The change over time of many LCACs was significantly different for DCD vs DBD, suggesting differential trends in fuel substrate utilization by ischemic injury pattern. Changes in leucine/isoleucine, arginine, C12:1-OH/C10:1-DC, and C16-OH/C14-DC were associated with increased odds of moderate-severe PGD. Neither end-of-run nor change in lactate or TnI was associated with PGD.
CONCLUSIONS: Metabolomic profiling of ex situ normothermic perfusion solution reveals a pattern of fuel substrate utilization that correlates with subclinical and clinical allograft dysfunction. This study highlights a potential role for interventions focused on fuel substrate modification in allograft conditioning during ex situ perfusion to improve allograft outcomes.