Advanced glycation end products induce choroidal endothelial cell proliferation, matrix metalloproteinase-2 and VEGF upregulation in vitro.
BACKGROUND
Advanced glycation end products (AGEs) are considered to be important modulators of angiogenesis and accumulate in choroidal neovascularization (CNV). Their effects regarding cells involved in proliferation of CNV [retinal pigment epithelial (RPE) cells, Müller cells and choroidal endothelial cells (CECs)] were investigated. Furthermore, the effects of AGEs on expression of matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) by CECs were explored.


METHODS
RPE cells, CECs and Müller cells were exposed to AGEs (10 microg/ml, 50 microg/ml and 100 microg/ml) for a time course of three days in their desired medium and proliferation was estimated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. MMP-2 expression of AGE-stimulated CECs was determined by zymography and reverse-transcription polymerase chain reaction (RT-PCR) after 36 h of exposure. Furthermore, VEGF expression of AGE-stimulated CECs (50 microg/ml and 100 microg/ml) was determined by RT-PCR after an exposure time of 36 h.


RESULTS
AGEs in a concentration of 50 microg/ml and 100 microg/ml increased the proliferation of CECs (41% vs 46.1%; P<0.005). No AGE effect on RPE cell and Müller cell proliferation was seen. AGEs in all concentrations used upregulated the VEGF mRNA expression of CECs. Zymography and RT-PCR demonstrated the upregulation of MMP-2 by CECs after AGE exposure.


CONCLUSIONS
AGEs stimulate CEC proliferation, MMP-2 secretion and VEGF upregulation and may be important promoters of CNV formation in exudative AMD in vivo.
Hoffmann
S
S
Department of Ophthalmology, University of Leipzig, Liebigstrasse 10-14, 03411 Leipzig, Germany.
Friedrichs
U
U
Eichler
W
W
Rosenthal
A
A
Wiedemann
P
P
D000818:Animals; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002829:Choroid / Q000098:blood supply*; D016228:Endothelial Growth Factors / Q000235:genetics / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000494:pharmacology*; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008222:Lymphokines / Q000235:genetics / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D017127:Glycation End Products, Advanced; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D020778:Matrix Metalloproteinase 2