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Cerebral emboli as a potential cause of Alzheimer's disease and vascular dementia: casecontrol study

BMJ 2006; 332 doi: (Published 11 May 2006) Cite this as: BMJ 2006;332:1119

Vascular dementia and Alzheimer’s disease: Do they have similar aetiologies?

The article by Purandare and colleagues suggests particulate cerebral
embolisation is equally important in the pathogenesis of vascular dementia
and Alzheimer’s disease (AD) in the elderly [1]. Platelets are the main
circulating source of amyloid â peptide (APP), accumulation of which is
believed to be the primary pathogenic mechanism in AD [2]. Platelets are
known to play a vital role in the complications of atherosclerosis and
have been demonstrated to release APP within atheroma [3]. Assuming that
platelet embolisation is important in the development of late onset AD
then anti-platelet medication should inhibit the onset or progression of
disease in a similar way to atherosclerosis. However, at present there is
no evidence to support this from the limited randomised trials completed
that have all utilised NSAIDs [4]. Similarly, if the aetiology of
atherosclerosis and AD are similar the age-adjusted incidence of AD would
be expected to follow that of vascular disease which does not appear to be
the case [3]. The findings of Purandare et al may equally reflect our
inability to differentiate vascular dementia and AD using clinical and
imaging criteria [5].

1. Purandare N, Burns A, Daly KJ, Hardicre J, Morris J, Macfarlane G,
McCollum C. Cerebral emboli as a potential cause of Alzheimer’s disease
and vascular dementia: case-control study. BMJ 2006;
2. Chen M, Inestrosa NC, Ross GS, Fernandez HL. Platelets are the primary
source of amyloid beta-peptide in human blood. Biochem Biophys Res Commun
3. Casserly I, Topol E. Convergence of atherosclerosis and Alzheimer’s
disease: inflammation, chole4sterol and misfolded proteins. Lancet
4. Aisen PS, Schafer KA, Grundman M, Pfeiffer E, Sano M, Davis KL, Farlow
MR, Jin S, Thomas RG, Thal LJ; Alzheimer's Disease Cooperative Study.
Effects of rofecoxib or naproxen vs placebo on Alzheimer disease
progression: a randomized controlled trial. JAMA. 2003;289:2819-26.
5. Varma AR, Laitt R, Lloyd JJ, Carson KJ, Snowden JS, Neary D, Jackson A.
Diagnostic value of high signal abnormalities on T2 weighted MRI in the
differentiation of Alzheimer's, frontotemporal and vascular dementias.
Acta Neurol Scand. 2002;105:355-64.

Competing interests:
None declared

Competing interests: No competing interests

30 April 2006
Jonathan Golledge
Professor of Vascular Surgery
Vascular Biology Unit, School of Medicine, James Cook University, Townsville. QLD. Australia. 4811