Resonance Raman Spectroscopic Measurement of Macular Carotenoids in Multiple Sclerosis

Abstract

Purpose: : The etiopathogenesis of Multiple Sclerosis (MS) has long been investigated.Evidence shows dietary factors and sun light exposure to play a role in the pathogenesis of MS and optic neuritis. Inhibition of the enzyme lipoxygenase by antioxidants is proved to reduce pro–inflammatory leukitrienes levels in the human retina.Patients with Relapsing Remitting (RR) Multiple Sclerosis are currently treated with Interferons (IFN) and synergistic effects of IFNs and retinoids have been reported. Macular carotenoids lutein and zeaxanthin act as powerfull antioxidant in the human macula and can be provided as dietary supplements.Aim of the study is to detect Macular Carotenoids concentrations in eyes of patients with RRMS and to verify wether these are related to disease activity, dietary habits or sigarette smoke.

Methods: : Macular Carotenoids (MC) concentration was measured by a Raman spectroscope on young normal subjects (23 eyes, age ranging from 23 to 42 years old) and on young patients with RRMS enrolled in the COGIMUS trial (14 eyes, age 32–56 years old) receiving beta–Interferon. We used: pupil dilation, self adjustment of the instrument and considered the best value out of three measures for each eye. Clinical data were collected on disease activity (Expanded Disability Status Scale,EDSS), ocular involvment, dietary consumption of fruit and vegetables, smoke habit.

Results: : Mean Macular Carotenoids concentration was 1486,84±9180 (SD) Raman counts in the RRMS, significantly lower than 2227,87±590 (SD) in the control group (p<0,05).Lower MCs concentrations were associated with higher EDSS scores (higher disability).

Conclusions: : In vivo measurements of Macular Carotenoids demonstrates low levels in course of RRMS. The pathogenesis of optic neuritis as well as the systemic disease activity could be affected by the antioxidant effect of carotenoids, both in the eyes and in the nervous system, so an increased consumption of vegetables and/or supplements containing them could be recommended. The investigation on MC concentrations by Raman spectroscopy in larger groups of MS patients could help providing customized side therapy and may add elements for unveiling the etiopathogenesis of the disease.

Keywords: carotenoids/carotenoid binding proteins • neuro-ophthalmology: optic nerve • antioxidants