97th DOG Annual Meeting 1999
IMMUNOHISTOCHEMICAL-BIOCHEMICAL CORRELATION OF AGING CHANGES IN BRUCH´S MEMBRANE
S. Wojtecki 2, M. Peuser 2, D. Müller 3, A. Heiligenhaus 2, D. Pauleikhoff 1
Purpose: In the pathogenesis of AMD especially of pigment epithelial detachments (PED) the developement of a hydrophobic barriere in Bruch´s Membrane (BM) is proposed. This is correlated with age-related deposition of lipids in BM. But because histologically in PED a detachment of the RPE from the outer layers of BM is visible, the developement of a hydrophobic barrier should be associated with a regression of adhesive molecules in BM. The attachment of the RPE cells to BM is promoted by the interaction of adhesive molecules like laminin, fibronectin and collagen IV. The purpose of the present study was to investigate the presence of these adhesive components in BM with age in correlation to the lipid deposition.
Methods: Macular specimes of 50 donor eye pairs of different age were analized. The composition of lipids deposited in BM were examined by histochemistry (Oil red O, Sudan black B) and chromatography. The results were correlated with the staining characteristcs in immunohistechemical analysis for different markers of adhesive components in BM (collagen IV, fibronectin, laminin).
Results: In the immunohistochemical analysis of collagen IV, laminin and fibrobectin a intensive staining was visible in the age group <40 y. in the RPE and choroidal endothelium cells basement membranes. In the age group 40-70 y. a decrease in staining intensity especially in the RPE basementmembrane was visible. In the age group >70 y. no staining was visible in the RPE basement membrane and a reduced intensity at the level of the endothelium cells. This change in the staining characteristics for adhesive molecules correlated with an increased staining intensity and amount of extracted lipids from BM between the different age groups.
Conclusions: The increase deposition of lipids in BM with age is consistent with the concept of the development of a hydrophobic barriere in BM. This finding correlated with an decrease of the staining intensity for different adhesive molecules especially in the basement membrane of the RPE cells and less pronounced in the basement membrane of endothelium cells with age. This regression of adhesive properties of the RPE cells to the outer layers of BM in association with the lipid depostion in BM may result in a possible detachment of the RPE and supports the pathogenetical concept of the developement of PED.
Supported by Deutsche Forschungsgemeinschaft (DFG HE1877/91)
(1) Augenabt. St. Franziskus Hospital, Hohenzollernring 72/74, 48145 Münster
(2) Universitätsaugenklnik Essen, Hufelandstr. 55, 44122 Essen
(3) Inst. für Mikrobiologie Universität Essen, Hufelandstr. 55, 44122 Essen