帕金森病患者皮肤神经磷酸化α-突触核蛋白研究

Skin nerve phosphorylated α synuclein deposits in patients with Parkinson′s disease

目的探讨帕金森病患者磷酸化α-突触核蛋白(phosphorylated α synuclein,p-α-syn)在皮肤神经中的沉积特点,以及其作为帕金森病外周生物标志物的可能性。方法纳入2017年6月1日至2018年8月31日就诊于郑州大学第一附属医院神经内科的15例帕金森病患者及同期年龄匹配的健康志愿者31名,进行13项小纤维神经病和症状问卷(SFN-SIQ)评分。将帕金森病患者按照主要临床表现分为运动迟缓(n=7)和静止性震颤(n=8)2个亚组,并以Hoehn-Yahr分级评价病情的严重程度,其中0~2.5级为早期组(n=11),3.0~5.0级为中晚期(n=4)。采用环形钻孔器取帕金森病患者小腿和颈部皮肤,健康对照组只取小腿部位皮肤,进行免疫组织化学和免疫荧光染色,观察p-α-syn在皮肤神经中的沉积情况并计数穿过单位长度基底膜的神经纤维数量即表皮内神经纤维密度(intraepidermal nerve fiber density,IENFD)。结果12/15的帕金森病患者表皮下神经丛、真皮神经束、汗腺、立毛肌、血管或毛囊周围神经中可见点状或线状p-α-syn沉积,健康对照组皮肤中未见沉积。p-α-syn在单个部位沉积的阳性率分别为小腿6/15、颈部7/15,总阳性率为12/15。帕金森病组的IENFD为(6.85±1.94)根/mm,较对照组[(10.45±3.70)根/mm]明显下降(t=-3.303,P=0.002),与SFN-SIQ评分呈负相关(r=-0.561,P=0.046)。疾病早期与中晚期患者之间,以及以震颤和以运动迟缓为主要表现的患者之间比较,p-α-syn沉积阳性率和IENFD差异均无统计学意义。结论p-α-syn在帕金森病患者皮肤神经纤维中沉积,伴随IENFD明显下降。提示皮肤神经中p-α-syn沉积可能是帕金森病固有的外周病理改变,有作为帕金森病患者诊断外周生物标志物的可行性。

Objective To investigate the characteristics of phosphorylated α-synuclein(p-α-syn)deposition in skin nerve fibers and its potential as a peripheral biomarker for Parkinson′s disease(PD).Methods Fifteen PD patients and 31 age-matched healthy controls were evaluated by Small-Fiber Neuropathy and Symptoms Inventory Questionnaire(SFN-SIQ),who were recruited in the Department of Neurology,the First Affiliated Hospital of Zhengzhou University from June 1,2017 to August 31,2018.PD patients were divided into two subgroups according to the main clinical manifestations:bradykinesia(n=7)and resting tremor(n=8),and the severity of the disease was evaluated by Honhn-Yahr classification,where 0 to 2.5 indicates early stage(n=11)and 3.0 to 5.0 indicates middle to late stage(n=4).Three-millimeter punch biopsies were taken from cervical seven paravertebral area and distal leg of PD patients,while the skin of the distal leg of healthy control group was only taken,followed by immunohistochemistry and double immunofluorescence staining.The intraepidermal nerve fiber density(IENFD)and the deposition characteristics of p-α-syn were studied.Results P-α-syn immuosignals were observed in 12/15 PD patients while in none of the control subjects,distributed in shape of dots or thread in the subepithelial plexus,dermis nerve tracts,and/or in the nerve fibers innervating sweat gland,muscle arrector pilorum,small blood vessels or hair follicle.The positive rate of p-α-syn deposition in a single site was 6/15 of the distal leg,7/15 of the cervical,and the total positive rate was 12/15.The IENFD of PD group was 6.85±1.94/mm,which was significantly lower than that of control group(10.45±3.70/mm,t=-3.303,P=0.002),and was negatively correlated with the SFN-SIQ(r=-0.561,P=0.046).There was no statistically significant difference in the positive rate of p-α-syn deposition and IENFD between patients with tremor and bradykinesia,nor between patients at stage of Hoehn-Yahr 0-2.5 and 3.0-5.0.Conclusions Cutaneous p-α-syn deposits in the nerve fibers of PD patients,with a significant decrease in IENFD.P-α-syn deposition in skin nerves may be an intrinsic peripheral pathological change of PD,and skin biopsy immunolabelling p-α-syn merits further study as a potential peripheral biomarker of in vivo PD diagnosis.