Abstract
Purpose :
Pericyte loss has been posited to be the crucial initial event in the pathologic cascade of diabetic retinopathy (DR), but this has not been verified in living humans. Here, we used adaptive optics scanning laser ophthalmology (AOSLO) to quantify pericyte density in healthy subjects and those with diabetes but no apparent DR (DMnoDR). We also analyzed pericyte density and optical coherence tomography angiography (OCTA) in eyes with diabetic macular edema (DME).
Methods :
We examined 17 healthy controls, 15 DMnoDR subjects, and 3 patients with DME and mild-moderate nonproliferative DR. For each vessel of interest, we imaged the vascular wall using AOSLO. For each vessel location, pericyte density was quantified as the number of pericytes/100 µm. OCTA vessel density (VD) values were obtained from the built-in AngioVue Analytics software. Student’s t-test was performed for statistical analysis.
Results :
DMnoDR eyes had a lower pericyte density than healthy eyes (5.0 ± 2.1 versus 6.5 ± 2.0 pericytes per 100 µm, p = 0.044). Although DME eyes did not have a statistically significantly lower pericyte density than DMnoDR eyes (p = 0.72), they had significantly lower VD in the superficial and deep capillary plexuses (p = 0.002, 0.0003 respectively).
Conclusions :
Our results indicate that pericyte density can serve as a quantitative biomarker of preclinical DR since it declines well before the onset of clinical DR. This could help guide the optimal timing of therapeutics aimed at preserving pericytes to prevent DR. We were surprised to find that eyes with DME did not show significantly lower pericyte density than eyes with DMnoDR. However, interestingly DME eyes did have significantly decreased VD suggesting that leakage is driven not only by pericyte loss but also by a higher load of retinal nonperfusion and ischemia, indicators of higher VEGF load.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.