Department of Critical Care Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.
Department of Critical Care Medicine, Changshou People's Hospital, Chongqing, 401220, China.
Rapid Commun Mass Spectrom. 2021 Jan 30;35(2):e8971. doi: 10.1002/rcm.8971.
The aim of this study was to analyze the metabolomics of lung with different host inflammation of acute respiratory distress syndrome (ARDS) for the identification of biomarkers for predicting severity under different inflammatory conditions.
Cecal ligation and puncture (CLP) and lipopolysaccharide (LPS)-intratracheal injection induced acute lung injury (ALI) were used. A mouse model was used to explore lung metabolomic biomarkers in ALI/ARDS. The splenectomy model was used as an auxiliary method to distinguish between hyper- and hypo-inflammatory subtypes. Plasma, lung tissue and bronchoalveolar lavage fluid (BALF) samples were collected from mice after CLP/LPS. The severity of lung injury was evaluated. Expression of tumor necrosis factor-α (TNF-α) in mice serum and lung was tested by enzyme-linked immunosorbent assay (ELISA) and polymer chain reaction (PCR). Polymorphonuclear cells in BALF were counted. The lung metabolites were detected by gas chromatography/mass spectrometry (GC/MS), and the metabolic pathways predicted using the KEGG database.
The LPS/CLP-Splen group had more severe lung injury than the corresponding ALI group; that in the CLP-Splen group was more serious than in the LPS-Splen group. TNF-α expression was significantly elevated in the serum and lung tissue after LPS or CLP, and higher in the LPS/CLP-Splen group than in the corresponding ALI group. The level of TNF-α in the CLP-Splen group was elevated significantly over that in the LPS-Splen group. Both these groups also showed significant neutrophil exudation within the lungs. During differential inflammation, more differential metabolites were detected in the lungs of the CLP group ALI mice than in the LPS group. A total of 41 compounds were detected in the lungs of the CLP and CLP-Splen groups. Contrastingly, eight compounds were detected in the lungs of the LPS and LPS-Splen groups. The LPS-Splen and CLP-Splen groups had significant neutrophil exudation in the lung. Random forest analysis of lung-targeted metabolomics data indicated 4-hydroxyphenylacetic acid, 1-aminocyclopentanecarboxylic acid (ACPC), cis-aconitic acid, and hydroxybenzoic acid as strong predictors of the hyper-inflammatory subgroup in the CLP group. Furthermore, with splenectomy, 13 differential metabolic pathways between the CLP and LPS groups were revealed.
Hyper-inflammatory subgroups of ARDS have a greater inflammatory response and a more active lung metabolism. Combined with the host inflammation background, biomarkers from metabolomics could help evaluate the response severity of ARDS.
本研究旨在分析不同宿主炎症急性呼吸窘迫综合征（ARDS）的肺代谢组学，以鉴定不同炎症状态下预测严重程度的生物标志物。
采用盲肠结扎穿孔（CLP）和脂多糖（LPS）气管内注射诱导急性肺损伤（ALI）。建立小鼠模型以探讨 ALI/ARDS 中的肺代谢组学生物标志物。脾切除术模型用于区分高炎症和低炎症亚型。收集 CLP/LPS 后小鼠的血浆、肺组织和支气管肺泡灌洗液（BALF）样本。评估肺损伤严重程度。通过酶联免疫吸附试验（ELISA）和聚合酶链反应（PCR）检测小鼠血清和肺组织中肿瘤坏死因子-α（TNF-α）的表达。计数 BALF 中的多形核细胞。通过气相色谱/质谱（GC/MS）检测肺代谢物，并使用 KEGG 数据库预测代谢途径。
LPS/CLP-脾组的肺损伤比相应的 ALI 组更严重；CLP-脾组比 LPS-脾组更严重。LPS 或 CLP 后血清和肺组织中 TNF-α表达明显升高，LPS/CLP-脾组明显高于相应的 ALI 组。CLP-脾组 TNF-α水平明显高于 LPS-脾组。这两组的肺部均有明显的中性粒细胞渗出。在差异炎症期间，CLP 组 ALI 小鼠的肺部检测到更多的差异代谢物，而 LPS 组仅检测到 8 种化合物。CLP 和 CLP-脾组的肺部共检测到 41 种化合物，而 LPS 和 LPS-脾组的肺部仅检测到 8 种化合物。LPS-脾和 CLP-脾组肺部有明显的中性粒细胞渗出。肺部靶向代谢组学数据的随机森林分析表明，CLP 组中，4-羟基苯乙酸、1-氨基环戊烷羧酸（ACPC）、顺乌头酸和羟基苯甲酸是预测高炎症亚组的强标志物。此外，脾切除术后，CLP 和 LPS 两组之间揭示了 13 条差异代谢途径。
ARDS 的高炎症亚组具有更强的炎症反应和更活跃的肺代谢。结合宿主炎症背景，代谢组学标志物有助于评估 ARDS 的反应严重程度。
