Assessment of candidate ocular biomarkers of ageing in a South African adult population: Relationship with chronological age and systemic biomarkers

Sophia Pathai,Clare E Gilbert,Stephen D Lawn,Helen A Weiss,Tunde Peto,Colin Cook,Tien Y Wong,Paul G Shiels

doi:10.1016/j.mad.2013.05.002

Abstract

Certain anatomic and functional parameters of the eye change with increasing chronological age. They may, therefore, serve as potential biomarkers of ageing. We investigated associations between four such ocular parameters (lens density, retinal vessel calibre, corneal endothelial cells and retinal nerve fibre layer thickness) and two ‘cellular’ biomarkers of ageing (leukocyte telomere length and CDKN2A expression), with frailty (a clinical correlate of biological ageing) in a population of South African adults. All ocular parameters revealed an association with either telomere length or CDKN2A expression. However, lens density was most strongly correlated with age, increased CDKN2A expression, and with frailty (p=0.05 and 0.03, respectively). Narrow retinal arteriolar diameter, associated with increased chronological age, was also associated with increased CDK2NA expression (0.42 vs. 0.31, p=0.02) but not with frailty. Ocular parameters may aid in determining biological age, warranting investigation in longitudinal studies.

Highlights

There is substantial variation in the health and functional status of older populations in many developing countries as well as in developed countries (Lloyd-Sherlock et al, 2012)
Objective measurement of lens density was the most informative ocular biomarker, with greater lens density associated with increased CDKN2A expression and with increased frailty status
Retinal arteriolar narrowing was associated with greater CDKN2A expression

Summary

Introduction

There is substantial variation in the health and functional status of older populations in many developing countries as well as in developed countries (Lloyd-Sherlock et al, 2012). The reasons for these variations are poorly understood, highlighting the need for translational age-related research within a global context (Salomon et al, 2013; Wang et al, 2013). Ã Corresponding author at: International Centre for Eye Health, Department of Clinical Research, LSHTM, Keppel Street, WC1E 7HT, UK. The disconnection between chronological age and lifespan has led to a search for effective and validated biomarkers of ageing (BoA), defined as ‘‘biological parameters of an organism that either alone or in some multivariate composite will better predict functional capability at some late age, than will chronological age’’ (Baker and Sprott, 1988)

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Methods

Conclusion