Aβ42 – APROMISSING NON-INVASIVE MARKER FOR LIFE-TIME DIAGNOSIS OF ALZHEIMER’S DISEASE

V.A. Zuev1, N.S. Lin’kova1, 2, V.O. Polyakova1, 3, E.M. Paltseva4, T.V. Kvetnaia1, E.O. Kukanova1, 2, V.V. Popuchiev5
1Saint Petersburg Institute of Bioregulation and Gerontology, Dunamo pr., 3, Saint Petersburg, 197110, Russian Federation;
2Peter the Great Saint Petersburg Polytechnic University, Polytechnicheskaya str. 29, Saint Petersburg, 195251, Russian Federation;
3Ott Instituteof Obstetrics, Gynecology and Reproductology, Mendeleevskaya line 3, Saint Petersburg, 199034, Russian Federation;
4B.V. Petrovsky Russian Research Scientific Center of Surgery, GSP-1, Abrikosovskyby street, 2, Moscow, 119991, Russian Federation;
5A.F. Tsyb Medical Radiological Research Centre – branch of the National Medical Research Radiological Centre of the Ministry
of Health of the Russian Federation, Koroleva street, 4, Obninsk, Kaluga region, 249036, Russian Federation

Introduction. Alzheimer's disease (AD) is a socially important neurodegenerative disease. The prevalence rate of AD is increasing over recent years. According to the hypothesis concerning AD to be a systematic disease its manifestation can be detected in various tissues. For example, in blood lymphocytes of AD patients there have been verified sedimentations of tau-protein and beta-amyloid precursor (Aβ42). However, the blood sampling is an invasive procedure, and therefore buccal epithelium (BE) seems to be preferable as promising target for non-invasive diagnosis of AD. Objective. The determination of Aβ42 expression in BE in AD patients of different ages. Methods. BE samples were obtained from AD patients (n=95, men and women, aged of 60–89 years) and from volunteers without psychoneurological disorders (n=25, men and women), which were matched for the gender and age by simple randomization method. BE samples were investigated by immunocytochemical, immunofluorescent confocal microscopy and Western blots. Results. Expression of the amyloid protein consisted of 42 amino acids length (Aβ42) in BE was demonstrated in 96.1% of AD patients. According to immunocytochemical study the square of Aβ42 expression in BE in old AD patients is by 95% higher than in elderly AD cases. The optical density of Aβ42 expression in the old patients is 31% higher compared to elderly patients with AD. Results of Western blot analysis showed that Aβ42 expression in BE of old patients to be twofold higher compared with elderly patients with AD. Conclusion. This is the first demonstration of clear difference in localization of beta amyloid precursor (Aβ42) in buccal cells between AD patients and healthy control.
Keywords: 
Alzheimer’s disease; buccal epithelium; beta amyloid precursor (Aβ42); aging; immunocytochemistry; confocal microscopy; Western blot