Abstract
Purpose :
To investigate the potential use of spontaneously dysmetabolic or diabetic aged Rhesus monkeys as a model of diabetic retinopathy.
Methods :
Ophthalmic examinations were performed on 60 Rhesus monkeys (aged 9.7 to 26.7 years) that had been classified by metabolic status as healthy, dysmetabolic, or diabetic, to determine if there were any ophthalmic differences that would enable a potential model of spontaneous diabetic retinopathy. The metabolic status of the animals was assessed longitudinally through glucose tolerance testing, and hemoglobin A1c (HbA1c), lipid profiles, and other metabolic parameters. For the animals that were diabetic, the disease state ranged from ~0.5 to 5 years. Examination procedures included indirect ophthalmoscopy, direct ophthalmoscopy (for higher magnification of optic disc/macula), slit lamp biomicroscopy, optical coherence tomography (OCT), intraocular pressure (IOP), and fundus photography. Fundus photographs were utilized for retinal vasculature biomarker assessments (retinal vessel diameter and tortuosity) and provided an additional clinical fundus assessment. OCT was performed primarily for measurement of retinal thickness. As part of the slit lamp biomicroscopic examination, the lenses of each animal were graded subjectively on a scale of 1 (low) to 5 (high) for relucency.
Results :
The clinical ophthalmoscopic findings potentially related to metabolic status included findings consistent with cotton wool spots in the retina in two animals (1 diabetic, 1 dysmetabolic) and edema in the cornea in one animal (diabetic). In the lens, there was a higher incidence of opacities and grade of relucency in the diabetic cohort, but these findings may have been confounded by the older age of the animals in this group. The remaining ophthalmoscopic findings were considered unrelated to metabolic status as they were observed either sporadically or without appreciable differences between groups. There were no differences in mean intraocular pressure, retinal thickness as determined by OCT, or retinal vasculature biomarkers based on metabolic status.
Conclusions :
The aged Rhesus monkeys with confirmed dysmetabolic or diabetic status did not appear to be a good model of spontaneous diabetic retinopathy.
This is a 2020 ARVO Annual Meeting abstract.