Additive effects of extra cellular matrix proteins and platelet derived mitogens on human retinal pigment epithelial cell proliferation and contraction.
OBJECTIVE
In proliferative vitreoretinopathy (PVR) retinal pigment epithelial cells (RPE) cells are thought to synthesize and interact with extracellular matrix (ECM) proteins to form fibrocellular membranes attached to the retina, which the cells then progressively contract detaching the retina. Haemorrhage into the eye is an exacerbating factor in the pathology. To investigate some of the possible interactions between ECM proteins, platelet mitogens and RPE cells in this study, we examined the combined effect of platelet derived mitogens and ECM proteins on RPE cell proliferation and contraction.


METHODS
Cells were cultured on a range of individual ECM proteins as well as on the ECM deposited by normal vitreous fluid and exposed to platelet mitogens. Effects on cell proliferation and cell detachment from these substrates and tissue culture plastic were examined.


RESULTS
We report additive/synergistic effects of platelet mitogens (PDGF and TGFb1) as well as bFGF, with ECM proteins (laminin, fibronectin, collagen 1 and vitreous-deposited ECM) on RPE proliferation. Further we report stimulation of RPE cell contraction on vitreous proteins when exposed to serum prepared from platelet-rich plasma. In this context it was noticeable that it was cells grown on vitreous matrix plus pigment rather than cells grown on clear vitreous that exhibited this behaviour.


CONCLUSIONS
This study supports a combined action of platelet mitogens and matrix proteins in inducing RPE cell proliferation and contractility and provides a simple in vitro model of some of the late stages of PVR.
Smith-Thomas
L
L
University Department of Medicine, Clinical Sciences Centre, Northern General Hospital, Sheffield S5 7AU, UK.
Richardson
P
P
Parsons
M A
MA
Rennie
I G
IG
Benson
M
M
MacNeil
S
S
D001792:Blood Platelets / Q000737:chemistry; D002448:Cell Adhesion / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D048429:Cell Size / Q000187:drug effects; D003470:Culture Media; D004357:Drug Synergism; D016326:Extracellular Matrix Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D008934:Mitogens / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D010857:Pigment Epithelium of Eye / Q000166:cytology* / Q000187:drug effects*
D003470:Culture Media; D016326:Extracellular Matrix Proteins; D008934:Mitogens