背景:多发性硬化症(MS)中神经变性的潜在机制仍然知之甚少,但主要涉及并非MS独有的分子途径。最近在MS脑组织中检测到的tau接种活性证实了先前在继发性和原发性进行性MS(PPMS)中过度磷酸化tau(p-tau)积累的神经病理学报道。我们旨在研究是否可以通过使用针对不同p-tau生物标志物的新型超灵敏免疫测定在MS患者的脑脊液(CSF)中检测到异常tau磷酸化。
方法:患有MS(n=55)和非炎性神经系统疾病(NIND,n=31)用靶向不同tau磷酸化位点(p-tau181、p-tau212、p-tau217和p-tau231)的内部单分子阵列(Simoa)测定进行分析。此外,神经丝光(NFL)和神经胶质纤维酸性蛋白(GFAP)通过多重Simoa测定法进行测量。患者被诊断为临床孤立综合征(CIS,n=10),复发缓解型MS(RRMS,n=21)和PPMS(n=24),根据2017年麦当劳标准,并进行了MRI检查,诊断时进行EDSS和基本CSF分析。
结果:病程进展的患者的p-tau水平比复发MS患者高1.4倍(p-tau217)至2.2倍(p-tau212)(PPMS与CISRRMS相比,p-tau181的p<0.001,p-tau212,p-tau231和p-tau217的p=0.042)。P-tau生物标志物与疾病持续时间相关(ρ=0.466-0.622,p<0.0001),诊断和随访时的年龄(ρ=0.318-0.485,p<0.02,除p-tau217外)和EDSS(ρ=0.309-0.440,p<0.02)。此外,p-tau生物标志物与GFAP相关(ρ=0.517-0.719,p≤0.0001),但与白蛋白商无关,CSF细胞计数或NFL。MRI病变负荷较高的患者的p-tau水平也较高,p≤0.01(<10vs.≥10个病灶,所有p≤0.01)。
结论:新型p-tau生物标志物的CSF浓度表明PPMS中的tau磷酸化程度高于RRMS。与年龄有关,疾病持续时间和EDSS表明这一过程随着疾病的严重程度而增加;然而,需要在更大的队列中复制这些结果,以进一步阐明MS整个疾病过程中tau磷酸化改变的相关性。
BACKGROUND: Mechanisms underlying neurodegeneration in multiple sclerosis (MS) remain poorly understood but mostly implicate molecular pathways that are not unique to MS. Recently detected tau seeding activity in MS brain tissues corroborates previous neuropathological reports of hyperphosphorylated tau (p-tau) accumulation in secondary and primary progressive MS (PPMS). We aimed to investigate whether aberrant tau phosphorylation can be detected in the cerebrospinal fluid (CSF) of MS patients by using novel ultrasensitive immunoassays for different p-tau biomarkers.
METHODS: CSF samples of patients with MS (n = 55) and non-inflammatory neurological disorders (NIND, n = 31) were analysed with in-house Single molecule array (Simoa) assays targeting different tau phosphorylation sites (p-tau181, p-tau212, p-tau217 and p-tau231). Additionally, neurofilament light (NFL) and glial fibrillary acidic protein (GFAP) were measured with a multiplexed Simoa assay. Patients were diagnosed with clinically isolated syndrome (CIS, n = 10), relapsing-remitting MS (RRMS, n = 21) and PPMS (n = 24) according to the 2017 McDonald criteria and had MRI, EDSS and basic CSF analysis performed at the time of diagnosis.
RESULTS: Patients with progressive disease course had between 1.4-fold (p-tau217) and 2.2-fold (p-tau212) higher p-tau levels than relapsing MS patients (PPMS compared with CIS + RRMS, p < 0.001 for p-tau181, p-tau212, p-tau231 and p = 0.042 for p-tau217). P-tau biomarkers were associated with disease duration (ρ=0.466-0.622, p < 0.0001), age (ρ=0.318-0.485, p < 0.02, all but p-tau217) and EDSS at diagnosis and follow-up (ρ=0.309-0.440, p < 0.02). In addition, p-tau biomarkers correlated with GFAP (ρ=0.517-0.719, p ≤ 0.0001) but not with the albumin quotient, CSF cell count or NFL. Patients with higher MRI lesion load also had higher p-tau levels p ≤ 0.01 (<10 vs. ≥ 10 lesions, all p ≤ 0.01).
CONCLUSIONS: CSF concentrations of novel p-tau biomarkers point to a higher degree of tau phosphorylation in PPMS than in RRMS. Associations with age, disease duration and EDSS suggest this process increases with disease severity; however, replication of these results in larger cohorts is needed to further clarify the relevance of altered tau phosphorylation throughout the disease course in MS.