Retinal biomarkers and Alzheimer

Citation: Translational Psychiatry (2013) 3, e233; doi:10.1038/tp.2012.150
Published online 26 February 2013

Retinal vascular biomarkers for early detection and monitoring of Alzheimer’s disease

S Frost^1,2,3, Y Kanagasingam^1,2, H Sohrabi⁴, J Vignarajan^1,2, P Bourgeat^1,5, O Salvado^1,5, V Villemagne^5,6,7, C C Rowe⁶, S Lance Macaulay⁸, C Szoeke^8,9, K A Ellis^7,9,10, D Ames^9,10, C L Masters⁷, S Rainey-Smith⁴ and R N Martins⁴ the AIBL Research Group

1. ¹Commonwealth Scientific and Industrial Research Organisation (CSIRO), Perth, WA, Australia
2. ²Preventative Health Flagship, Australian e-Health Research Centre, Perth, WA, Australia
3. ³School of Psychiatry and Clinical Neurosciences, University of Western Australia, Perth, WA, Australia
4. ⁴Centre of Excellence for Alzheimer’s Disease Research and Care, School of Medical Sciences, Edith Cowan University, The McCusker Alzheimer’s Research Foundation, Hollywood Medical Centre, Perth, WA, Australia
5. ⁵CSIRO Preventative Health Flagship, Australian e-Health Research Centre, Brisbane, QLD, Australia
6. ⁶Department of Nuclear Medicine and Centre for PET, Austin Health, Melbourne, VIC, Australia
7. ⁷The Mental Health Research Institute (MHRI), University of Melbourne, Melbourne, VIC, Australia
8. ⁸CSIRO Preventative Health Flagship, materials Science and Engineering, Melbourne, VIC, Australia
9. ⁹National Ageing Research Institute, Melbourne, VIC, Australia
10. ¹⁰Department of Psychiatry, University of Melbourne, Melbourne, VIC, Australia
11. ¹¹Australian Imaging, Biomarker and Lifestyle (AIBL) Study, Melbourne, VIC, Australia

Correspondence: Professor RN Martins, Centre of Excellence for Alzheimer’s Disease Research and Care, School of Medical Sciences, Edith Cowan University, The McCusker Alzheimer’s Research Foundation, Suite 22, Hollywood Medical Centre, 85 Monash Avenue, Nedlands, Perth, WA 6009, Australia. E-mail: ralph.n.martins@gmail.com

Received 21 September 2012; Revised 26 November 2012; Accepted 2 December 2012

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Abstract

The earliest detectable change in Alzheimer’s disease (AD) is the buildup of amyloid plaque in the brain. Early detection of AD, prior to irreversible neurological damage, is important for the efficacy of current interventions as well as for the development of new treatments. Although PiB-PET imaging and CSF amyloid are the gold standards for early AD diagnosis, there are practical limitations for population screening. AD-related pathology occurs primarily in the brain, but some of the hallmarks of the disease have also been shown to occur in other tissues, including the retina, which is more accessible for imaging. Retinal vascular changes and degeneration have previously been reported in AD using optical coherence tomography and laser Doppler techniques. This report presents results from analysis of retinal photographs from AD and healthy control participants from the Australian Imaging, Biomarkers and Lifestyle (AIBL) Flagship Study of Ageing. This is the first study to investigate retinal blood vessel changes with respect to amyloid plaque burden in the brain. We demonstrate relationships between retinal vascular parameters, neocortical brain amyloid plaque burden and AD. A number of RVPs were found to be different in AD. Two of these RVPs, venular branching asymmetry factor and arteriolar length-to-diameter ratio, were also higher in healthy individuals with high plaque burden (P=0.01 and P=0.02 respectively, after false discovery rate adjustment). Retinal photographic analysis shows potential as an adjunct for early detection of AD or monitoring of AD-progression or response to treatments.

Keywords: 

Alzheimer’s; retina; eye; aging; screening; vasculature