Abstract
Purpose :
PDGF-B/PDGFRβ signaling plays a well-established role during normal vascular development, and as well as physiological and pathological angiogenesis [Andrae et. al., Genes Dev. 2008, 10: 1276-312]. In previous studies, we show that using a neutralizing antibody against PDGFRβ (α-PDGFRβ) reduces pericytes coverage and effects vessel morphology and growth in developing retinal vessels in pups but not mature vessels in adult mice [Cheung et al. IOVS 2014; E-Abstract 4361]. Also, this effect causes microaneurysms, retinal hemorrhage and edema, which are characteristic of diabetic retinopathy [Lee et al. IOVS 2015; E-Abstract 2312]. In this study, we are establishing model of diabetic retinopathy using treatment of neonatal mouse pups with anti-PDGFRβ antibody and following developmental changes.
Methods :
C57Bl/6 pups were given a subcutaneous (SC) injection of α-PDGFRβ (25mg/kg at P2 and at P5). Samples were collected at P8, P16, and P21 (Study 1). Some α-PDGFRβ pretreated pups were administered with aflibercept at P7. Samples were collected at P8 and P16 (Study 2). Fc was used as a control. Pericyte coverage was assessed using α-NG2 (Millipore) and vasculature was visualized using GS Lectin I (Vector Labs). SDOCT (Heidelberg) was used to observe and document changes in ocular anatomy in vivo.
Results :
Two injections of α-PDGFRβ antibody (25mg/kg dose, at P2 and P5), resulted in complete stripping of pericytes, caused irregularities in blood vessel caliber and changed the density of the retinal vascular network. At P8 pericyte depletion induced microaneurysms. Later timepoints, (P16) there was a pronounced infiltration of the inflammatory cells indicating continued tissue remodeling and blood vessel leakiness. Systemic administration of the aflibercept at P7 produced partial normalization of the blood vessel structure and limited the infiltration of leucocytes observed at P8, with still more complete normalization of blood vessel structure and morphology at P16.
Conclusions :
These studies demonstrate that selective pharmacological blockade of PDGFRβ is effective in contributing to changes in vascular morphology in developing retinal neovessels that mimics vascular abnormalities in diabetic retinopathy. Aflibercept administration partially restores the vascular structure and morphology and alleviates leucocyte infiltration.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.