Abstract
Purpose::
The goal of our study is to describe and quantify the change in DR and ROP vascular morphology following treatment with TA.
Methods::
Binary (black/white) and linearized images suitable for vascular quantification were extracted from grayscale digital images obtained by clinical fluorescein angiography (FA) of patients diagnosed with nonproliferative diabetic retinopathy (NPDR), by fluorescence confocal microscopy of a postnatal ROP murine model, and by brightfield microscopy of the angiogenic quail chorioallantoic membrane (CAM). The highly vascularized, transparent, two-dimensional CAM serves as an experimental model for development of new vascular analytical techniques. Effects on vascular morphology following TA treatment are being quantified by an integrated set of vascular morphological parameters that include Euclidean distance mapping (EDM, a measure of vessel diameter), the fractal dimension, vessel length density, and branching analyses of vascular trees and capillary networks using the NASA Glenn computer code VESGEN, currently undergoing development as a publicly available software plug-in to NIH ImageJ.
Results::
By qualitative inspection of 63 CAM specimens treated at seven concentrations of TA in two independent experiments, application of TA resulted thinning of blood vessels and inhibition of the growth of new, small blood vessels. Preliminary analysis of human retinal images appear consistent with a previously published study (Avakian et al., Curr. Eye Res., 24(4):274). By VESGEN analysis of murine ROP, vascular density in the pre-angiogenic ROP retina decreased approximately 2.5X compared to control. Quantitative studies of the TA-treated human NPDR retina, murine ROP retina, and CAM are in progress.
Conclusions::
Application of TA to the angiogenic CAM inhibited vascular growth and altered the morphology of blood vessels. We are currently applying vascular quantification methods developed for the CAM and human NPDR retina to the analysis of TA treatment effects on the human NPDR retina, murine ROP retina, and angiogenic CAM.
Keywords: retinal neovascularization • diabetic retinopathy • retinopathy of prematurity