Targeted Disruption of the FGF2 Gene Does Not Prevent Choroidal Neovascularization in a Murine Model

Abstract

Choroidal neovascularization (CNV) is the major cause of severe visual loss in patients with age-related macular degeneration. Laser treatment is helpful for a minority of patients with CNV, and development of new treatments is hampered by a poor understanding of the molecular signals involved. Several lines of evidence have suggested that basic fibroblast growth factor (FGF2) plays a role in stimulating CNV. In this study, we tested this hypothesis using mice with targeted disruption of the FGF2 gene in a newly developed murine model of laser-induced CNV. One week after krypton laser photocoagulation in C57BL/6J mice, 34 of 60 burns (57%) showed fluorescein leakage and 13 of 16 (81%) showed histopathological evidence of CNV. At 2 weeks, CNV was detected in 9 of 10 burns (90%) in which a bubble had been observed at the time of the laser treatment. Electron microscopy showed fenestrated vessels with large lumens within choroidal neovascular lesions. Two weeks after laser-induced rupture of Bruch's membrane, 27 of 36 burns (75%) contained CNV in FGF2-deficient mice compared with 26 of 30 (87%) in wild-type control mice, a difference that is not statistically significant. This study demonstrates that FGF2 is not required for the development of CNV after laser-induced rupture of Bruch's membrane and provides a new model to investigate molecular mechanisms and anti-angiogenic therapy in CNV.

ADAMTS-2 functions as anti-angiogenic and anti-tumoral molecule independently of its catalytic activity

“…Fourteen days after LASER impact, the delay for maximal neovascularization [31], the mice were perfused with dextranfluorescein and the vascular density was evaluated using confocal microscopy and digital image capture. Neovascularization was observed only at the sites initially injured by the LASER and was significantly and reproducibly higher in ADAMTS-2 as compared to WT mice (Fig.…”

Fibroblast growth factor/fibroblast growth factor receptor system in angiogenesis

“…Indeed, fgf2 knockout mice are morphologically normal [87] and do not show differences in neovascularization following injury [88] or hypoxia [89]. Conversely, transgenic overexpression of FGF2 does not result in spontaneous or inherent vascular defects, even though an amplified angiogenic response can be observed after wounding or s.c. implantation of a Matrigel plug [90].…”

Angiopoietin 1 inhibits ocular neovascularization and breakdown of the blood–retinal barrier

“…It also occurs in diseases in which there are ruptures or cracks in Bruch's membrane such as high myopia and traumatic rupture of Bruch's membrane. Laser-induced rupture of Bruch's membrane provides a useful model of choroidal neovascularization in mice 23 and this model was used to assess the effect of increased expression of Ang1 on choroidal neovascularization. Bruch's membrane was ruptured in three locations in each eye of adult TetCMVAng1 mice.…”

“…23 Adult double hemizygous TetOpsinAng1 mice and controls that carried only one of the transgenes had rupture of Bruch's membrane in three locations in each eye with laser photocoagulation. Mice were anesthetized with ketamine hydrochloride (100 mg/kg body weight) and the pupils were dilated with 1% tropicamide.…”

“…Burns were performed in the 9, 12, and 3 o'clock positions of the posterior pole of the retina. Production of a bubble at the time of laser, which indicates rupture of Bruch's membrane, is an important factor in obtaining CNV, 23 so only burns in which a bubble was produced were included in the study. On the day of laser treatment, the control mice and the double transgenics started to receive 2 mg/ml of doxycycline in their drinking water.…”