Extracellular release of tissue plasminogen activator is increased with the phagocytic activity of the retinal pigment epithelium.
Primary confluent cultures of retinal pigment epithelium (RPE) cells harvested from porcine eyes were challenged with latex spheres. The extracellular release of tissue plasminogen activator (t-PA) that was associated with phagocytosis of the beads by the RPE was measured by using enzyme-linked immunosorbent and chromogenic substrate assays. In the presence of serum and as compared to the controls, the phagocytosis of latex spheres produced a 5.5-fold increase in the amount of t-PA released into the ambient medium. Cell lysis was not a significant feature in either treated or control groups. Because the RPE in vivo is exposed to serum through the fenestrated choriocapillaris, and because phagocytosis by the RPE outer segments shed by the photoreceptors contributes to the maintenance of the functional integrity of the neural retina, we suggest that the release of t-PA associated with the phagocytic activity of RPE cells is an important physiologic event.
Tripathi
B J
BJ
Department of Ophthalmology and Visual Science, University of Chicago, Illinois.
Park
J K
JK
Tripathi
R C
RC
D000818:Animals; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D007840:Latex; D010587:Phagocytosis / Q000502:physiology*; D010857:Pigment Epithelium of Eye / Q000378:metabolism / Q000502:physiology*; D013552:Swine; D010959:Tissue Plasminogen Activator / Q000378:metabolism*
D007840:Latex; D010959:Tissue Plasminogen Activator