In Vivo Assessment of Molecular Aging by Quasi-Elastic Light Scattering in the Human Lens

Abstract

Purpose : Crystallin proteins comprise ~90% of lens protein in mature lens fiber cells, do not undergo turnover, and thus remain extant throughout life. Crystallins undergo various post-translational modifications during aging. We hypothesize that cumulative alterations in the lens may constitute an in vivo biomarker of molecular aging for the human body.

Methods : Quasi-elastic light scattering (QLS) has been used to study the aggregation of lens proteins. Here we use QLS to measure changes in human lens proteins as a function of time in vitro and aging in vivo. We investigated changes in light scattering in vivo from the lenses of 34 healthy human subjects without history of eye disease (18 males, 16 females). Measurements were acquired in the nucleus along the optical axis at a predetermined distance from the anterior capsule of the lens.

Results : QLS detected time-dependent changes in scattering intensity, hydrodynamic radius, and supramolecular order of human lens proteins during long-term incubation (~1 yr) and in response to oxidation in vitro. Changes in the time-dependent QLS signal observed in vitro mirror changes in the age-dependent QLS signal detected in lenses of healthy humans across a wide age range (5 to 61 years).

Conclusions : QLS assessment of long-lived protein in the human lens can provide a practical noninvasive technique for objective evaluation of molecular aging in vivo.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.