we now present data indicating that ( a ) an identical protein is secreted by bovine retinal pericytes , ( b ) this protein is plasminogen activator inhibitor-type i ( pai-1 ) , as revealed by immunoprecipitation with specific antibodies and reverse fibrin zymography , and ( c ) retinal endothelial cells and pericytes synthesize different species of matrix macromolecules , that is : type iv collagen is the major collagen secreted by endothelial cells , whereas pericytes produce predominantly type i collagen ;
C0009333
type iv collagen
C0009325
collagen