Journal of Hepatology ( IF 26.8 ) Pub Date : 2021-08-25 , DOI: 10.1016/j.jhep.2021.08.009 Ingrid W Zhang 1 , Anna Curto 2 , Cristina López-Vicario 1 , Mireia Casulleras 1 , Marta Duran-Güell 1 , Roger Flores-Costa 1 , Benoit Colsch 3 , Ferran Aguilar 2 , Ana M Aransay 4 , Juan José Lozano 5 , María Hernández-Tejero 6 , David Toapanta 6 , Javier Fernández 7 , Vicente Arroyo 2 , Joan Clària 8
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Background & Aims
Patients with acute-on-chronic liver failure (ACLF) present a systemic hyperinflammatory response associated with increased circulating levels of small-molecule metabolites. To investigate whether these alterations reflect inadequate cell energy output, we assessed mitochondrial morphology and central metabolic pathways with emphasis on the tricarboxylic acid (TCA) cycle in peripheral leukocytes from patients with acutely decompensated (AD) cirrhosis, with and without ACLF.
Methods
The study included samples from patients with AD cirrhosis (108 without and 128 with ACLF) and 41 healthy individuals. Leukocyte mitochondrial ultrastructure was visualized by transmission electron microscopy and cytosolic and mitochondrial metabolic fluxes were determined by assessing NADH/FADH2 production from various substrates. Plasma GDF15 and FGF21 were determined by Luminex and acylcarnitines by LC-MS/MS. Gene expression was analyzed by RNA-sequencing and PCR-based glucose metabolism profiler array.
Results
Mitochondrial ultrastructure in patients with advanced cirrhosis was distinguished by cristae rarefication and swelling. The number of mitochondria per leukocyte was higher in patients, accompanied by a reduction in their size. Increased FGF21 and C6:0- and C8:0-carnitine predicted mortality whereas GDF15 strongly correlated with a gene set signature related to leukocyte activation. Metabolic flux analyses revealed increased energy production in mononuclear leukocytes from patients with preferential involvement of extra-mitochondrial pathways, supported by upregulated expression of genes encoding enzymes of the glycolytic and pentose phosphate pathways. In patients with ACLF, mitochondrial function analysis uncovered break-points in the TCA cycle at the isocitrate dehydrogenase and succinate dehydrogenase level, which were bridged by anaplerotic reactions involving glutaminolysis and nucleoside metabolism.
Conclusions
Our findings provide evidence at the cellular, organelle and biochemical levels that severe mitochondrial dysfunction governs immunometabolism in leukocytes from patients with AD cirrhosis and ACLF.
Lay summary
Patients at advanced stages of liver disease have dismal prognosis due to vital organ failures and the lack of treatment options. In this study, we report that the functioning of mitochondria, which are known as the cell powerhouse, is severely impaired in leukocytes of these patients, probably as a consequence of intense inflammation. Mitochondrial dysfunction is therefore a hallmark of advanced liver disease.
中文翻译：
线粒体功能障碍控制慢加急性肝衰竭患者白细胞的免疫代谢
背景与目标
慢加急性肝衰竭 (ACLF) 患者会出现全身性高炎症反应，与循环中小分子代谢物水平的增加有关。为了研究这些改变是否反映了细胞能量输出不足，我们评估了线粒体形态和中枢代谢途径，重点是急性失代偿 (AD) 肝硬化患者外周白细胞中的三羧酸 (TCA) 循环，有和没有 ACLF。
方法
该研究包括来自 AD 肝硬化患者（108 名无 ACLF 和 128 名患有 ACLF）和 41 名健康个体的样本。通过透射电子显微镜观察白细胞线粒体超微结构，并通过评估各种底物产生的NADH/FADH 2来确定细胞溶质和线粒体代谢通量。血浆 GDF15 和 FGF21 由 Luminex 测定，酰基肉碱由 LC-MS/MS 测定。通过 RNA 测序和基于 PCR 的葡萄糖代谢分析仪阵列分析基因表达。
结果
晚期肝硬化患者的线粒体超微结构以嵴稀疏和肿胀为特征。患者中每个白细胞的线粒体数量较高，同时体积减小。FGF21 和 C6:0-和 C8:0-肉碱的增加可预测死亡率，而 GDF15 与白细胞活化相关的基因集特征密切相关。代谢通量分析显示，优先参与线粒体外途径的患者单核白细胞的能量产生增加，这得到糖酵解和戊糖磷酸途径编码酶基因表达上调的支持。在 ACLF 患者中，线粒体功能分析揭示了 TCA 循环中异柠檬酸脱氢酶和琥珀酸脱氢酶水平的断点，
结论
我们的研究结果提供了细胞、细胞器和生化水平的证据，表明严重的线粒体功能障碍控制 AD 肝硬化和 ACLF 患者白细胞的免疫代谢。
总结
由于重要器官衰竭和缺乏治疗选择，处于肝病晚期的患者预后不佳。在这项研究中，我们报告说，被称为细胞强国的线粒体的功能在这些患者的白细胞中严重受损，这可能是强烈炎症的结果。因此，线粒体功能障碍是晚期肝病的标志。
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