Lipid metabolites as potential diagnostic and prognostic biomarkers for acute community acquired pneumonia

Early diagnosis of acute community-acquired pneumonia (CAP) is important in patient triage and treatment decisions. To identify biomarkers that distinguish patients with CAP from non-CAP controls, we conducted an untargeted global metabolome analysis for plasma samples from142 patients with CAP (CAP cases) and 97 without CAP (non-CAP controls). Thirteen lipid metabolites could discriminate between CAP cases and non-CAP controls with area-under-the-receiver-operating-characteristic curve of > 8 (P ≤ 10-9). The levels of glycosphingolipids, sphingomyelins, lysophosphatidylcholines and L-palmitoylcarnitine were higher, while the levels of lysophosphatidylethanolamines were lower in the CAP cases than those in non-CAP controls. All 13 metabolites could distinguish CAP cases from the non-infection, extrapulmonary infection and non-CAP respiratory tract infection subgroups. The levels of trihexosylceramide (d18:1/16:0) were higher, while the levels of lysophosphatidylethanolamines were lower, in the fatal than those of non-fatal CAP cases. Our findings suggest that lipid metabolites are potential diagnostic and prognostic biomarkers for CAP.

急性社区获得性肺炎（Community-Acquired Pneumonia, CAP）的早期诊断对于患者分诊与治疗决策至关重要。为筛选可区分CAP患者与非CAP对照人群的生物标志物，本研究针对142例CAP患者（CAP病例组）与97例非CAP对照者的血浆样本开展了非靶向全局代谢组学分析。13种脂质代谢物可有效区分CAP病例组与非CAP对照组，其受试者工作特征曲线下面积（Area Under the Receiver Operating Characteristic Curve, AUC）大于0.8（P ≤ 10^-9）。与非CAP对照组相比，CAP病例组的糖鞘脂、鞘磷脂、溶血磷脂酰胆碱及L-棕榈酰肉碱水平更高，而溶血磷脂酰乙醇胺水平更低。上述13种代谢物均可区分CAP病例与非感染、肺外感染及非CAP呼吸道感染亚组人群。在致命性CAP病例中，三己糖基神经酰胺（d18:1/16:0）水平更高，而溶血磷脂酰乙醇胺水平较非致命性CAP病例更低。本研究结果表明，脂质代谢物可作为CAP潜在的诊断与预后生物标志物。