Analyses of Clinical Features and Investigations on Potential Mechanisms in Patients with Alzheimer’s Disease and Olfactory Dysfunction

Article type: Research Article

Authors: Zuo, Li-jun^a | Guo, Peng^a | Liu, Li^b | Yu, Shu-yang^a | Lian, Teng-hong^a | Yu, Qiu-jin^a | Hu, Yang^a | Jin, Zhao^a | Wang, Rui-dan^a | Piao, Ying-shan^a | Li, Li-xia^b | Wang, Ya-jie^c | Wang, Xiao-min^d | Zhang, Wei^{e; f; g; h; i; *}

Affiliations: [a] Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China | [b] Department of Internal Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China | [c] Core Laboratory for Clinical Medical Research, Beijing Tiantan Hospital, Capital Medical University, Beijing, China | [d] Department of Physiology, Capital Medical University, Beijing, China | [e] Center for Cognitive Neurology, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China | [f] China National Clinical Research Center for Neurological Diseases, Beijing, China | [g] Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing, China | [h] Center of Parkinson’s Disease, Beijing Institute for Brain Disorders, Beijing, China | [i] Beijing Key Laboratory on Parkinson’s Disease, Beijing, China

Correspondence: [*] Correspondence to: Wei Zhang, MD, PhD, Center for Cognitive Neurology, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China. E-mail: [email protected].

Abstract: Background:OD is common in patients with Alzheimer’s disease (AD). However, the relationship between OD and clinical symptoms and the potential mechanisms of OD in AD patients are still unknown. Objective:To explore the relationship between OD and clinical symptoms and the potential mechanisms of OD in AD patients. Methods:We evaluated OD using the Hyposmia Rating Scale (HRS), classified patients into AD with OD (AD-OD) and AD with no OD (AD-NOD) groups, and detected the levels of free radicals and inflammatory factors, including hydroxyl radical (•OH), hydrogen peroxide (H2O2), nitric oxide, interleukin-1β, interleukin-6, tumor necrosis factor-α, and prostaglandin E2 in serum from AD patients. Results:It was shown that the scores of the Mini-Mental State Examination, Animal Fluency Test, Boston Naming Test (BNT), and Auditory Verbal Learning Test-delayed recall were all significantly lower and the score of overall activity of daily living (ADL) and instrumental ADL were significantly higher in AD-OD group than those in AD-NOD group. Compared with AD-NOD group, •OH level in serum was prominently elevated, and H2O2 level was dramatically declined in AD-OD group. In the correlation analysis, HRS score was significantly and positively correlated with the score of BNT, and negatively correlated with •OH level in serum. Conclusions:AD-OD patients suffered from severe cognitive impairment in the domain of language. Oxidative stress might be correlated with AD-OD featured by the drastically increased •OH level in serum.

Keywords: Alzheimer’s disease, language, •OH , olfactory dysfunction, oxidative stress

DOI: 10.3233/JAD-180425

Journal: Journal of Alzheimer's Disease, vol. 66, no. 2, pp. 789-799, 2018