Abstract
Purpose :
Diabetic retinopathy (DR) is a leading cause of blindness in diabetes mellitus (DM). We use Optical coherence tomography angiography (OCTA) to assess the retinal vasculature density (VD) changes in highly translatable diabetic non-human primate (NHP) models before the earliest changes in retinal thickness (RT), Foveal avascular zone (FAZ) area.
Methods :
KBI currently has over 3000 male cynomolguses with metabolic diseases caused by either high fat diet (HFD) feeding or natural aging. Metabolic disease was monitored longitudinally using body weight, intravenous glucose tolerance tests (ivGTT), blood pressure and clinical chemistry. Diabetes mellitus were diagnosed based on results from ivGTT.
For the assessment of retinal vasculature using OCTA, all monkeys were anesthetized with IM ketamine (5-10 mg/kg) and xylazine (0.5-1 mg/kg). OCTA scanned after pupil dilated with topical 1% tropicamide ophthalmic. RT and VD in fovea and para-fovea in the superficial layer (ILM-IPL) and deeper layer (IPL-RPE of RT and IPL-OPL of VD), FAZ was assessed using OCTA.
Results :
As a progress report, total of 65 eyes from monkeys have been studies, in which 35 eyes from diabetic monkeys and 30 eyes from non-diabetic monkeys. In diabetic monkey eyes, RT in fovea, parafovea in the superficial layer and foveal, parafovea in the deep layer were (in mean±se) 41.0±1.2, 93.7±1.7, 187.5±2.6 and 204.7±1.8, respectively. In non-diabetic monkey eyes, these were 43.9±1.2, 96.1±1.9, 209.5±3.6 and 209.5±3.6. FAZ areas were 0.34±0.12 and 0.32±0.02 in diabetic eyes and non-diabetic eyes, respectively. There is no significant difference. However, in diabetic monkey eyes, retinal VD in fovea, para fovea in the superficial layer and in fovea, parafovea in the deep layer were, 10.39±0.94, 45.61±1.30, 27.42±1.47 and 52.94±0.98, respectively. In non-diabetic monkey eyes, those were 13.96±0.99, 50.50±1.00, 33.23±1.34 and 57.48±0.65. The VD in diabetic monkey eyes was significantly smaller than that in non-diabetic monkey eyes (p<0.05 or p<0.01).
Conclusions :
Retinal VD in eyes from diabetic monkeys is significantly smaller than that in eyes from non-diabetic monkeys before changes in RT and FAZ. These results provided an earlier indication of retinal vasculature changes before any sign of diabetic retinopathy.
This is a 2020 ARVO Annual Meeting abstract.