Abstract
Purpose :
Aberrant vessel growth is a common hallmark of retinal diseases such as retinopathy of prematurity and diabetic retinopathy, ultimately leading to blindness. Here we investigated whether CTGF, a reported target gene and modifier of vascular endothelial growth factor, is involved in vessel loss, neovascularization and intraretinal capillary development under pathological conditions.
Methods :
The transgenic bB1-CTGF1 mice (lens-specific CTGF overexpression) and the conditional inducible knockout CtgfCoin/Coin;CAGGCre-ER mice (tamoxifen treatment: 5mg/ml; 3x/d for 5d; referred to as CtgfΔeye) were analyzed in the oxygen-induced retinopathy model. Mice were exposed to 75% oxygen from postnatal day (P)7 to P12 and returned to room air until final analysis. Wildtype and Ctgf Coin/Coin littermates served as controls. On P17 mice were perfused with FITC-conjugated dextran and the area of neovascular tufts, avascular zone and the deep vascular plexus were quantified on retinal flat mounts and plotted as percentage of the total area. Intraretinal capillary development and blood-retinal barrier maintenance were investigated in a crossbreed of Ndp-deficient mice, which completely lack intraretinal capillaries and the bB1-CTGF6 mice, with an high CTGF overexpression, by FITC-conjugated dextran perfusion and immunohistochemistry against plasmalemma vesicle-associated protein, Caveolin-1 and Claudin-5.
Results :
CtgfΔeye mice show a significant larger avascular area (16.68 ± 1.33 %; control: 8.30 ± 1.44 %; p < 0.01) and area of neovascularization (1.09 ± 0.17 %, control: 0.51 ± 0.09 %; p < 0.05), while the development of the deep retinal capillaries was significantly diminished (CtgfΔeye: 18.74 ± 2.75 %; control: 29.19 ± 3.94 %; p < 0.05), compared to controls. In contrast, bB1-CTGF1 mice showed a significantly smaller area of neovascular tufts (0.14 ± 0.02 %; control: 0.41 ± 0.08 %; p < 0.05), avascular zone (5.22 ± 1.13 %; control: 8.62 ± 1.17%; p < 0.01) and larger area of the deep vascular plexus (53.41 ± 5.07 %; control: 38.64 ± 3.86 %; p < 0.05). Immunohistochemistry showed that the bB1-CTGF6 mice do not rescue the lack of retinal capillaries and the impaired blood-retinal-barrier in Ndp-deficient mice.
Conclusions :
We conclude that CTGF is an important mediator of vascular integrity in the mouse retina that stabilizes retinal vessels and promotes regrowth of capillaries after oxygen-induced vascular damage.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.