Supplementary file 1_Early cerebrospinal fluid elevations of pTau-217 in severe traumatic brain injury subjects.docx

IntroductionTauopathies, including Alzheimer’s disease (AD), feature abnormal accumulations of hyperphosphorylated Tau protein; however, their biomarker potential in traumatic brain injury (TBI) is not well-defined. This study investigated whether cerebrospinal fluid (CSF) phosphorylated Tau at threonine-217 (pTau-217) could serve as an early biomarker for severe TBI (sTBI).
MethodsCSF samples from 26 sTBI patients, collected between 6 and 240 h post-injury, and 19 healthy controls were analyzed using an optimized direct enzyme-linked immunosorbent assay (ELISA; sensitivity <4.7 pg/mL) for pTau-217 detection, complemented by Western blot validation. Temporal analysis, ROC curves, and trajectory clustering were used for interpretation.
ResultsCSF pTau-217 levels were significantly elevated in sTBI patients at 6, 12, 18, 24, and 48 h post-injury compared to controls (p < 0.05–p < 0.001), peaking around 18 h (~65 ng/mL) before declining to near-control levels by 120 h. ROC analyses showed AUC of 0.78 (6–12 h) and 0.83 (24–48 h). Clustering identified a subgroup with sustained high pTau-217, associated with diffuse axonal injury and worse 6-month outcomes. A significant inverse correlation was observed between CSF pTau-217 at 24–48 h and GOSE (ρ = –0.67, p < 0.01).
DiscussionThese findings indicate that CSF pTau-217 is a sensitive and early biomarker of acute tau pathology in sTBI. Its diagnostic performance and association with axonal injury and outcome support its utility, though longitudinal validation in larger cohorts is required to confirm clinical relevance.

引言
τ蛋白病（Tauopathies）以阿尔茨海默病（Alzheimer’s disease, AD）为代表，其核心病理特征为过度磷酸化Tau蛋白的异常聚集；然而此类蛋白在创伤性脑损伤（traumatic brain injury, TBI）中的生物标志物潜力尚未得到明确阐释。本研究旨在探讨脑脊液（cerebrospinal fluid, CSF）中苏氨酸217位点磷酸化Tau蛋白（phosphorylated Tau at threonine-217, pTau-217）能否作为重型创伤性脑损伤（severe TBI, sTBI）的早期生物标志物。

方法
本研究对26名伤后6至240小时采集脑脊液样本的重型创伤性脑损伤患者，以及19名健康对照者的脑脊液样本进行了分析；采用优化的直接酶联免疫吸附试验（direct enzyme-linked immunosorbent assay, ELISA; 检测灵敏度<4.7 pg/mL）检测pTau-217水平，并以蛋白质印迹（Western blot）进行验证。研究通过时序分析、受试者工作特征曲线（receiver operating characteristic curve, ROC）及轨迹聚类对数据展开解读。

结果
与健康对照组相比，重型创伤性脑损伤患者在伤后6、12、18、24及48小时的脑脊液pTau-217水平均显著升高（p < 0.05至p < 0.001），并于伤后18小时左右达到峰值（约65 ng/mL），随后逐渐下降，至120小时左右降至接近对照组的水平。ROC分析显示，伤后6-12小时区间的曲线下面积（AUC）为0.78，24-48小时区间为0.83。轨迹聚类鉴定出一个持续维持高pTau-217水平的亚组，该亚组与弥漫性轴索损伤及较差的6个月预后显著相关。伤后24-48小时的脑脊液pTau-217水平与扩展格拉斯哥预后评分（Glasgow Outcome Scale Extended, GOSE）呈显著负相关（ρ = –0.67, p < 0.01）。

讨论
本研究结果表明，脑脊液pTau-217是重型创伤性脑损伤急性期τ蛋白病理改变的敏感早期生物标志物。其良好的诊断性能以及与轴索损伤和预后的关联，支持其临床应用价值，但仍需在更大规模队列中开展纵向验证，以确认其临床相关性。