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Blood basement membrane alterations in human retinal microaneurysms during aging
Author(s) -
RUBERTE J,
LOPEZLUPPO M,
RAMOS D,
MENDESJORGE L,
NAVARRO M,
CARRETERO A,
RODRIGUEZBAEZA A,
NACHER V
Publication year - 2012
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2012.t021.x
Subject(s) - basement membrane , laminin , fibronectin , type iv collagen , perlecan , retinal , immunohistochemistry , biology , retina , microbiology and biotechnology , pathology , chemistry , anatomy , extracellular matrix , medicine , biochemistry , immunology , proteoglycan , neuroscience
Purpose Different studies indicates that the presence of retinal microaneurysms, dilations of the capillaries which often develop as gross outpouchings of the vessel wall, appears during human aging. However, little is known about the mechanisms involved in the development of these structures. The aim of this study was to examine whether basement membrane protein expression and organization changes during the formation of retinal microaneuryms. Methods Human retinas were obtained from 17 donors: 14 old‐donors and 3 middle‐aged donors. Basement membrane proteins (collagen IV, laminin, fibronectin, nidogen), perlecan and MMP‐9 expression were analyzed in paraffin sections and whole‐mount formalin fixed retinas using immunohistochemistry and laser‐confocal microscopy. The structure of basement membrane was analyzed by TEM. Results Microaneurysms were present in all the retinas obtained from old donors but were absent in the retinas obtained from midle‐aged donors. Microaneurysms were classified as Type I (early stage) and Type II (advanced stage). We observed that all basement membrane proteins increased its expression in Type I microaneurysms, but they disminished in Type II microaneuryms. In addition, MMP‐9 was strongly expressed in microaneurysms producing basement membrane disorganization. Conclusion Collagen IV, laminin, fibronectin, nidogen and perlecan were increased in Type I microaneurysm basement membrane. A concommitant expression of MMP‐9 could explain the disorganization of blood basement membrane components.