The effect of AMA0428, a novel and potent ROCK inhibitor, in a model of neovascular age-related macular degeneration.

Purpose: Rho kinase (ROCK) is associated with VEGF-driven angiogenesis, as well as with inflammation and fibrosis. Therefore, the effect of AMA0428, a novel ROCK inhibitor, was studied in these processes, which highly contribute to the pathogenesis of neovascular AMD.

Methods: The effect of AMA0428 (0.5-5.0 μM) on human umbilical vein endothelial cells (HUVECs), human brain microvascular endothelial cells (HBMECs), and human brain microvascular pericytes (HBVPs) was determined using cell viability (WST-1), apoptosis (caspase 3/7), and migration (scratch and under-agarose) assays. The in vivo response was investigated using a laser-induced choroidal neovascularization (CNV) mouse model, in which intravitreal injections of AMA0428, murine anti-VEGF-R2 mAb (DC101), or placebo was given. Outcome was assessed by analysis of inflammation (CD45), angiogenesis (FITC-dextran), vessel leakage (Texas Red-conjugated Dextran and FITC-labeled lectin) and fibrosis (Sirius Red/Collagen I).

Results: The AMA0428 dose-dependently reduced proliferation and VEGF-induced migration of HUVEC and HBMEC (P < 0.05). No significant effect was seen on HBVP proliferation; however, migration and pericyte recruitment were enhanced (P < 0.05) by AMA0428 administration. There was no apoptosis induction. The AMA0428 significantly reduced CNV and vessel leakage 2 weeks after laser treatment, comparable to DC101. In addition, AMA0428 inhibited inflammation on day 5 by 42% (P < 0.05) and collagen deposition on day 30 by 43% (P < 0. 05), whereas DC101 had no effect on inflammation nor on fibrosis.

Conclusions: The results suggest that targeting ROCK with AMA0428 not only reduces neoangiogenesis, but also blocks inflammation and fibrosis (contrary to VEGF suppression). These results point to a potential therapeutic benefit of ROCK inhibition in neovascular AMD.