TY - JOUR
T1 - Structure and conformation of the carotenoids in human retinal macular pigment
AU - Arteni, Ana Andreea
AU - Fradot, Mathias
AU - Galzerano, Denise
AU - Mendes-Pinto, Maria M.
AU - Sahel, José Alain
AU - Picaud, Serge
AU - Robert, Bruno
AU - Pascal, Andrew A.
N1 - Publisher Copyright:
Copyright © 2015 Arteni et al.
PY - 2015/8/27
Y1 - 2015/8/27
N2 - Human retinal macular pigment (MP) is formed by the carotenoids lutein and zeaxanthin (including the isomer meso-zeaxanthin). MP has several functions in improving visual performance and protecting against the damaging effects of light, and MP levels are used as a proxy for macular health-specifically, to predict the likelihood of developing age-related macular degeneration. While the roles of these carotenoids in retinal health have been the object of intense study in recent years, precise mechanistic details of their protective action remain elusive. We have measured the Raman signals originating from MP carotenoids in ex vivo human retinal tissue, in order to assess their structure and conformation. We show that it is possible to distinguish between lutein and zeaxanthin, by their excitation profile (related to their absorption spectra) and the position of their ?1 Raman mode. In addition, analysis of the ?4 Raman band indicates that these carotenoids are present in a specific, constrained conformation in situ, consistent with their binding to specific proteins as postulated in the literature. We discuss how these conclusions relate to the function of these pigments in macular protection. We also address the possibilities for a more accurate, consistent measurement of MP levels by Raman spectroscopy.
AB - Human retinal macular pigment (MP) is formed by the carotenoids lutein and zeaxanthin (including the isomer meso-zeaxanthin). MP has several functions in improving visual performance and protecting against the damaging effects of light, and MP levels are used as a proxy for macular health-specifically, to predict the likelihood of developing age-related macular degeneration. While the roles of these carotenoids in retinal health have been the object of intense study in recent years, precise mechanistic details of their protective action remain elusive. We have measured the Raman signals originating from MP carotenoids in ex vivo human retinal tissue, in order to assess their structure and conformation. We show that it is possible to distinguish between lutein and zeaxanthin, by their excitation profile (related to their absorption spectra) and the position of their ?1 Raman mode. In addition, analysis of the ?4 Raman band indicates that these carotenoids are present in a specific, constrained conformation in situ, consistent with their binding to specific proteins as postulated in the literature. We discuss how these conclusions relate to the function of these pigments in macular protection. We also address the possibilities for a more accurate, consistent measurement of MP levels by Raman spectroscopy.
UR - http://www.scopus.com/inward/record.url?scp=84943328905&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0135779
DO - 10.1371/journal.pone.0135779
M3 - Article
C2 - 26313550
AN - SCOPUS:84943328905
VL - 10
JO - PLoS ONE
JF - PLoS ONE
SN - 1932-6203
IS - 8
M1 - e0135779
ER -
