Olfactory Dysfunction and Its Association With Neuropathologic Proteins in Cerebrospinal Fluid From Patients With Parkinson Disease

Peng Guo; Rui-Dan Wang; Teng-Hong Lian; Du-Yu Ding; Ya-Nan Zhang; Wei-Jiao Zhang; Dan-Ning Li; Li-Xia Li; Jing-Hui Li; Hui-Ying Guan; Shu-Yang Yu; Li Liu; Yang Hu; Li-Jun Zuo; Qiu-Jin Yu; Xiao-Min Wang; Wei Zhang

doi:10.3389/fnagi.2020.594324

Olfactory Dysfunction and Its Association With Neuropathologic Proteins in Cerebrospinal Fluid From Patients With Parkinson Disease

Front Aging Neurosci. 2020 Dec 11:12:594324. doi: 10.3389/fnagi.2020.594324. eCollection 2020.

Authors

Peng Guo¹, Rui-Dan Wang¹, Teng-Hong Lian¹, Du-Yu Ding¹, Ya-Nan Zhang², Wei-Jiao Zhang¹, Dan-Ning Li¹, Li-Xia Li³, Jing-Hui Li¹, Hui-Ying Guan¹, Shu-Yang Yu¹, Li Liu³, Yang Hu¹, Li-Jun Zuo¹, Qiu-Jin Yu¹, Xiao-Min Wang⁴, Wei Zhang^{5

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Affiliations

¹ Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
² Department of Blood Transfusion, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
³ Department of General Internal Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
⁴ Department of Physiology, Capital Medical University, Beijing, China.
⁵ Department of Neurology, Center for Cognitive Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
⁶ China National Clinical Research Center for Neurological Disease, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
⁷ Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Beijing, China.
⁸ Beijing Key Laboratory on Parkinson Disease, Beijing, China.

Abstract

Background and Purpose: Olfactory dysfunction (OD) is a common non-motor symptom of Parkinson disease (PD). However, the relationship between OD and neuropathologic proteins in cerebrospinal fluid (CSF) from PD patients remains unclear. Methods: 166 PD patients were included in the study. Overall olfactory function was assessed by summing up the scores of olfactory threshold, discrimination, and identification by a Sniffin' Sticks test, based on which, patients were divided into PD with OD (PD-OD) and PD with no OD (PD-NOD) groups. CSF samples were obtained from 76 PD patients. The levels of neuropathologic proteins, including α-Synuclein, Aβ1-42, total tau (T-tau), and multiple forms of phosphorylated tau (P-tau) in CSF were measured by an enzyme-linked immunosorbent assay. Results: out of the 166 PD patients, 103 cases (62.0%) had OD. The scores of overall olfactory functions, and olfactory threshold, discrimination, and identification in the PD-OD group were all significantly lower than that in the PD-NOD group (P < 0.001). α-Synuclein level in CSF was significantly higher in the PD-OD group than the PD-NOD group (P < 0.05), and was significantly and negatively correlated with the scores of overall olfactory function, and olfactory discrimination and identification (P < 0.05). Aβ1-42 level in CSF was higher in the PD-OD group than the PD-NOD group, and was significantly and negatively correlated with the olfactory identification score (P < 0.05). T-tau level in CSF was significantly lower in the PD-OD group than the PD-NOD group (P < 0.05), and was significantly and positively correlated with the olfactory discrimination score (P < 0.05). There was no significant difference in P-tau level in CSF between the PD-OD and PD-NOD groups and no correlation between OD score and P-tau level in CSF. Conclusions: PD-OD includes the impairments of olfactory threshold, discrimination, and identification, and is associated with the significant elevation of α-Synuclein and the decrease of the T-tau level in CSF.

Keywords: Parkinson disease; cerebrospinal fluid; neuropathologic proteins; olfactory dysfunction; sniffin' sticks test.