Detection of specific extracellular matrix molecules in drusen, Bruch's membrane, and ciliary body

We used specific antibodies to localize a variety of extracellular matrix components by indirect immunofluorescence reactions on cryostat sections of drusen-bearing human donor eye tissue. These included collagen types I through V, fibronectin, laminin, heparan sulfate-containing basement membrane proteoglycan as well as antibodies to human IgG and IgM. The composition of drusen with respect to these specific molecules varied greatly, even within the same region of an eye. Hard or nodular drusen were more likely to show a discrete organized layer of specific basement membrane molecules over their apical surfaces than were diffuse type drusen. Diffuse but not nodular drusen generally contained fibronectin. Immunohistochemical reactivity of Bruch's membrane showed age-related accumulation of type I collagen and localized changes associated with some drusen.