The extracellular matrix of human retinal pigment epithelial cells in vivo and its synthesis in vitro.

The production of extracellular matrix material by retinal pigment epithelium (RPE) may influence or mediate some of the many important functions of this tissue. Using immunohistochemical staining techniques, the extracellular matrix surrounding the RPE in vivo and the components produced by RPE in vitro have been investigated. Frozen sections of eye bank eyes showed antigen specific staining for collagen types I, III, and IV, and for fibronectin and laminin in Bruch's membrane and surrounding the RPE. Only very slight staining of the membrane was seen with antiserum against type II collagen, and there was no staining for type V collagen. Specific staining was demonstrated for the four collagens and glycoproteins in the extracellular matrix of RPE cells grown in culture. Once again, there was no staining for type V collagen. This study demonstrates that the RPE is capable of producing many of the components of the extracellular matrix found in Bruch's membrane and surrounding the RPE in vivo. This function may be important in the maintenance of a physical barrier to subretinal neovascularization, and may also play a role in such pathologic states as proliferative vitreoretinopathy.