Differences in the temporal expression of regulatory growth factors during choroidal neovascular development.
Although the roles of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and hepatocyte growth factor (HGF) in pathologic neovascularization have been well characterized in certain tissues, their particular functions and expression patterns in choroidal neovascularization (CNV) have not been clearly established. After localized laser trauma to Bruch's membrane to induce CNV development, the temporal changes in mRNA and protein expression of these 3 cytokines were documented and compared histologically to areas of immunofluorescence, the proliferation of endothelial cells, neovascular development, and temporal changes in vascular permeability. Changes in mRNA and protein levels of bFGF and HGF occurred quickly and reached peak expression within hours. This activity corresponded in time to intense and localized immunofluorescence for these cytokines within the choriocapillaris within laser lesion sites. During this same initial time period, mRNA upregulation of VEGF occurred, primarily within the neural retina and this expression corresponded to intense immunolabeling of Müller cells immediately adjacent to the lesion sites. By 3 days after lasering, increased VEGF(164) protein expression was measurable, whereas early neovascular development histologically corresponded to HGF and bFGF mRNA expansion into the developing choroidal neovascular membrane (CNVM). At 7 days, CNV expansion, maturation, and increased vascular permeability corresponded to peak VEGF mRNA and protein expression and to immunofluorescence of the CNVM. Differences also occurred in the expression of precursor and activated isoforms of these cytokines in the retinal pigment epithelium/choroid as compared to those in the retina. These molecular and immunocytochemical results suggest that bFGF and HGF may be important as initial regulators neovascularization in this CNV model; whereas VEGF may be important during later phases of angiogenesis and neovascular hyperpermeability.
Hu
Wenzheng
W
Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202-5175, USA.
Criswell
Mark H
MH
Fong
Shao-Ling
SL
Temm
Constance J
CJ
Rajashekhar
Gangaraju
G
Cornell
Tammy L
TL
Clauss
Matthias A
MA
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002199:Capillary Permeability; D020256:Choroidal Neovascularization / Q000209:etiology / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D018450:Disease Progression; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D017228:Hepatocyte Growth Factor / Q000235:genetics / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D017075:Laser Coagulation; D008297:Male; D008856:Microscopy, Fluorescence / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011914:Rats, Inbred BN; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D016222:Fibroblast Growth Factor 2; D017228:Hepatocyte Growth Factor