Age-related liquefaction of the human vitreous body: LM and TEM evaluation of the role of proteoglycans and collagen.
OBJECTIVE
To evaluate morphologic aspects of age-related liquefaction of the human vitreous body by light and electron microscopy to provide a basis from which future studies directed at the pathogenesis of this phenomenon can be undertaken. The study focuses on changes in fibrillar collagen and proteoglycans (PGs).


METHODS
Morphologic aspects of intravitreal liquefied spaces and matrix areas surrounding them were examined in 13 adult human donor eyes (aged 21-80 years) by light (LM) and transmission electron microscopy (TEM). Collagen fibrils were visualized by using standard contrasting methods. PGs were specifically stained by cupromeronic blue (CB).


RESULTS
Eyes from older donors contained larger spaces than eyes from younger ones. Transitions between matrix and spaces were abrupt or gradual. In transition areas of all specimens, a gradual decrease in the number of collagen fibers, and to a lesser extent of PGs was observed. In addition, a fragmentation of collagen fibers and an aggregation of PG-molecules around these fragments were found. Neither cells nor their fragments were observed in these areas.


CONCLUSIONS
This is the first study to evaluate vitreous liquefaction at the light and electron microscopic level. A breakdown of collagen fibrils into smaller fragments seems to be crucial to the pathogenesis of age-related liquefaction of the human vitreous body. The mechanism inducing fragmentation of vitreous fibrils has yet to be elucidated. From the absence of cells and cellular remnants in all specimens, it is tentatively concluded that an extracellular process is involved.
Los
Leonoor I
LI
Department of Ophthalmology, University Hospital, University of Groningen, Groningen, The Netherlands. l.i.los@ohk.azg.nl
van der Worp
Roelofje J
RJ
van Luyn
Marja J A
MJ
Hooymans
Johanna M M
JM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003094:Collagen / Q000378:metabolism* / Q000648:ultrastructure; D005128:Eye Diseases / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007202:Indicators and Reagents; D007211:Indoles; D008875:Middle Aged; D009942:Organometallic Compounds; D011509:Proteoglycans / Q000378:metabolism* / Q000648:ultrastructure; D014822:Vitreous Body / Q000378:metabolism* / Q000648:ultrastructure
D007202:Indicators and Reagents; D007211:Indoles; D009942:Organometallic Compounds; D011509:Proteoglycans; C015445:copper phthalocyanine; D003094:Collagen