The tau protein of oral epithelium increases in Alzheimer's disease.
BACKGROUND
Alzheimer's disease (AD) is an important problem that should be solved in the 21st century. Prior to treatment, a simple and easy diagnostic method using biological markers should be available. As a method to attain this goal, we detected and determined tau protein in oral mucosal epithelium.


METHODS
Oral epithelium was exfoliated from 34 patients with AD or 29 patients with vascular dementia, and 33 young and 34 age-matched controls. Western blot was performed for determining the molecular weight of oral tau protein. The tau protein level was determined with an enzyme-linked immunosorbent assay (ELISA) kit for cerebrospinal fluid (CSF). CSF tau was also measured and compared with oral tau.


RESULTS
Western blot analysis using an anti-non-phosphorylated tau-protein antibody showed two bands, one at 65 Kd and the other at 110 Kd. The tau-protein level in oral epithelia showed a significant positive correlation with those in the CSF (p <.05). The patients with AD had significantly higher levels of tau protein than the patients with vascular dementia and the controls (p <.01). AD patients with a younger age at onset of the study showed a higher level of the tau protein than the patients with later age at onset (p <.05).


CONCLUSIONS
Like other nonneural tissues, oral epithelium contains small tau and big tau. The tau protein in oral epithelium reflects the pathological changes, as does the CSF tau. Individuals who develop AD may have had high levels of the tau protein in oral mucosal epithelium since early childhood. The tau-protein level in oral epithelia could be helpful in diagnosing AD.
Hattori
Hideyuki
H
Department of Geriatric Medicine, Kanazawa Medical University, Ishikawa, Japan. hideyuki@kanazawa-med.ac.jp
Matsumoto
Masayuki
M
Iwai
Kunimitu
K
Tsuchiya
Hiroshi
H
Miyauchi
Eiji
E
Takasaki
Mikihiro
M
Kamino
Kouzin
K
Munehira
Junichi
J
Kimura
Yasuhiro
Y
Kawanishi
Kenichi
K
Hoshino
Tomoko
T
Murai
Hiroshi
H
Ogata
Hajime
H
Maruyama
Hidemichi
H
Yoshida
Hiroshi
H
D000328:Adult; D000368:Aged; D000544:Alzheimer Disease / Q000378:metabolism*; D015153:Blotting, Western; D015140:Dementia, Vascular / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D009061:Mouth Mucosa / Q000378:metabolism*; D009994:Osmolar Concentration; D020033:Protein Isoforms / Q000378:metabolism; D012016:Reference Values; D016875:tau Proteins / Q000134:cerebrospinal fluid / Q000737:chemistry / Q000378:metabolism*
D020033:Protein Isoforms; D016875:tau Proteins