Abstract
Purpose :
Techniques such as fluorescein angiography (FA) are utilized ubiquitously to visualize the vasculature in the eye. While the generation of these images has become highly sophisticated, no similar advances have been made in methods to quantify.
Methods :
Six-month-old C57BL/6J wild type, transgenic Notch 3 knock-out (N3KO) mice, and N3KO mice that express a mutant human Notch 3 protein in mural cells were examined by FA. The latter mutation cause a pathology referred to as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathies (CADASIL), which is characterized by mural cell degeneration. FA (n =4 per strain) were analyzed with a novel ImageJ macro developed to measure the diameter and number of large vessels at multiple radial distances from the optic nerve.
Results :
CADASIL mice have on average one fewer vessels stemming from their optic nerves compared to N3KO mice (p = 0.0023) and three fewer vessels (p = 0.003) compared to control mice. The number of peripheral vessels plateaus to 10 for the CADASIL mice compared to the 11.3 vessels for the N3KO mice and 12.5 vessels for wild type mice (p = 0.06 and p = 0.01, respectively). The CADASIL mice exhibit trend toward increased vessel diameter with increasing distance from the optic nerve; 0.008 µm/µm compared to the decreasing standard deviations of average vessel diameter in the N3KO mice 0.028 µm/µm and 0.033 µm/µm in the control mice, p = 0.042 and p = 0.022 respectively.
Conclusions :
Quantitative analysis of FA demonstrates differences in the vasculatures of CADASIL mice compared to N3KO and wild type control mice, including reduced number of large caliber vessels, lower frequency of vessel branching and increased standard deviation of vessel diameter radially from the optic nerve. These data suggest that the CADASIL mutation impairs vessel patterning and triggers a compensatory mechanism.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.