Platelet amyloid precursor protein abnormalities in mild cognitive impairment predict conversion to dementia of Alzheimer type: a 2-year follow-up study.
BACKGROUND
Alteration of the amyloid precursor protein (APP) forms ratio has been described in the platelets of patients with dementia of Alzheimer type (DAT) and in a subset of subjects with mild cognitive impairment (MCI).


OBJECTIVE
To evaluate the potential role of the platelet APP forms ratio in predicting progression from MCI to DAT.


METHODS
Thirty subjects with MCI underwent a clinical and neuropsychological examination and a determination of the platelet APP forms ratio. Subjects were followed up periodically for 2 years, and the progression to dementia was evaluated.


METHODS
Community population-based sample of patients admitted for memory complaints.


RESULTS
Patients who progressed to DAT at the 2-year follow-up (n = 12) showed a significant decrease of baseline platelet APP forms ratio values (mean +/- SD, 0.36 +/- 0.28) compared with stable MCI subjects (mean +/- SD, 0.73 +/- 0.32) (P<.01) and patients who developed other types of dementia (mean +/- SD, 0.83 +/- 0.27) (P =.03). By fixing a cutoff score of 0.6, 10 (83%) of the 12 DAT patients showed baseline values below the cutoff, whereas 10 (71%) of 14 subjects who either developed non-Alzheimer-type dementia or maintained cognitive functions had values in the normal range.


CONCLUSIONS
Mild cognitive impairment is a major risk factor for DAT, and Alzheimer disease-related pathological changes can be identified in patients converting to DAT within a 2-year follow-up.
Borroni
Barbara
B
Department of Neurology, University of Brescia, Brescia, Italy.
Colciaghi
Francesca
F
Caltagirone
Carlo
C
Rozzini
Luca
L
Broglio
Laura
L
Cattabeni
Flaminio
F
Di Luca
Monica
M
Padovani
Alessandro
A
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis / Q000209:etiology*; D016564:Amyloid beta-Protein Precursor / Q000097:blood*; D001792:Blood Platelets / Q000378:metabolism*; D003072:Cognition Disorders / Q000097:blood* / Q000150:complications* / Q000175:diagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011379:Prognosis; D012307:Risk Factors
D016564:Amyloid beta-Protein Precursor