Purpose : To investigate layer specific retinal vascular reactivity (RVR) in capillaries of diabetic subjects with no or mild non-proliferative diabetic retinopathy (NPDR). Methods : A previously described nonrebreathing apparatus was used to deliver room air, 5% CO 2 , or 100% O 2 to 41 controls and 22 diabetic subjects (with mild or no NPDR) while simultaneously acquiring fovea-centered 3x3mm 2 Swept-Source Optical Coherence Tomography Angiography. Vessel skeleton density (VSD) and vessel diameter index (VDI) were calculated for each gas condition for the superficial retinal layer (SRL) and deep retinal layer (DRL). The superficial layer analysis excluded regions of arterioles and venules. Data analysis was performed using mixed factorial analysis of covariance stratified by diabetic status. All models were adjusted for age, gender, and hypertension. Results : Among controls, there was a significant difference in capillary VSD between all gas conditions (p<0.001). This difference was present in both the SRL and DRL. Among diabetics, there was no significant difference in response to CO 2 conditions in the SRL (p=0.072), and a blunted response to both CO 2 and O 2 in the DRL. A significant gas effect was detected in the capillary VDI in the SRL of controls (p=0.001), which was driven by higher VDI in the oxygen condition compared to that of carbon dioxide. Conclusions : Impairment in RVR in diabetic subjects is driven largely by a decrease in the magnitude of the capillary response to O 2 in the DRL as well as almost complete attenuation of capillary CO 2 response in all layers. These layer and gas specific impairments in diabetics seem to occur early in the disease and to be driven primarily at the capillary level.

中文翻译：

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糖尿病受试者中的层特异性视网膜血管反应性受损

目的：研究无或轻度非增生性糖尿病视网膜病变（NPDR）的糖尿病受试者的毛细血管中的层特异性视网膜血管反应性（RVR）。方法：使用先前描述的非呼吸设备向41名对照组和22名糖尿病患者（轻度或无NPDR）输送室内空气，5％CO 2或100％O 2，同时获取以中央凹为中心的3x3mm 2扫频光源相干断层扫描血管造影。针对浅表视网膜层（SRL）和深视网膜层（DRL）的每种气体条件，计算血管骨架密度（VSD）和血管直径指数（VDI）。表层分析排除了小动脉和小静脉的区域。使用按糖尿病状态分层的协方差的混合因子分析进行数据分析。所有模型都针对年龄，性别，和高血压。结果：在对照组中，所有气体条件之间的毛细管VSD均存在显着差异（p <0.001）。SRL和DRL中都存在这种差异。在糖尿病患者中，SRL对CO 2条件的反应无显着差异（p = 0.072），而DRL对CO 2和O 2的反应均较弱。在对照组的SRL中，在毛细管VDI中检测到显着的气体效应（p = 0.001），这是由于氧气条件下的VDI高于二氧化碳所致。结论：糖尿病受试者的RVR受损主要是由于DRL中对O 2的毛细血管反应幅度的降低以及所有层中毛细血管CO 2反应的几乎完全衰减所致。