Abstract
Purpose: :
To examine retinal reactivity across the glucose spectrum in individuals with pre-diabetes and type 2 diabetes and to determine whether alterations in reactivity is associated with a marker of inflammation. We hypothesized that individuals with pre-diabetes and type 2 diabetes would be associated with impaired retinal reactivity and that altered reactivity would be associated with higher levels of inflammatory biomarkers.
Methods: :
Middle aged to older individuals with pre-diabetes (n=6), type 2 diabetes (n=18) and healthy age matched controls (n=12) were recruited. We used the novel retinal-imaging device known as the Dynamic Vessel Analyzer to examine retinal artery and venous reactivity. Retinal reactivity was measured during a 6-minute flickering light stimulation, which involves a short series of light flashes exposed to one eye of the individual. We calculated the overall percent change in amplitude of the retinal vessel’s diameter change to the flicker stimulus. The amplitude change in diameter was calculated from two components: maximal vasodilator response of the vessel’s diameter during the flicker stimulus and maximal vasoconstrictor response of the vessel’s diameter after completion of the light stimulus. Fasting high sensitive c-reactive protein (hsCRP) was measured as a biomarker of inflammation.
Results: :
Pre-diabetic and diabetic Individuals compared to healthy controls had attenuated amplitude changes in retinal arterial diameters to the flicker-light stimulus (2.1± .9% and 4.9 ± .5% vs. 8.3 ± 1.1 %, respectively, P<0.05). This finding was primarily influenced by an attenuated dilator response. There was no significant association between hsCRP levels and retinal vessel’s maximal vasodilation response or change in amplitude.
Conclusions: :
Retinal reactivity is impaired in both pre-diabetics and diabetics individuals. The inflammatory biomarker, hsCRP, was not associated with changes in retinal reactivity.
Keywords: blood supply • retina • diabetes