Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America.
Department of Bioengineering, University of Washington, Seattle, Washington, United States of America.
PLoS One. 2020 Sep 11;15(9):e0233871. doi: 10.1371/journal.pone.0233871. eCollection 2020.
To investigate layer specific retinal vascular reactivity (RVR) in capillaries of diabetic subjects without DR or with only mild non-proliferative diabetic retinopathy (NPDR).
A previously described nonrebreathing apparatus was used to deliver room air, 5% CO2, or 100% O2 to 41 controls and 22 diabetic subjects (with mild or no NPDR) while simultaneously acquiring fovea-centered 3x3mm2 Swept-Source Optical Coherence Tomography Angiography (SS-OCTA) images. 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 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, and statistical significance for multiple comparisons from posthoc comparisons were defined at p<0.017.
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 CO2 conditions in the SRL (p = 0.072), and a blunted response to both CO2 (p = 0.9) and O2 in the DRL (p = 0.019). 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.
Impairment in RVR in diabetic subjects is characterized by a paradoxical response to CO2 in both the SRL and DRL as well as an attenuated response to O2 in the DRL. These layer and gas specific impairments in diabetics seem to occur early in the disease and to be driven primarily at the capillary level.
研究无糖尿病视网膜病变（DR）或仅有轻度非增生性糖尿病视网膜病变（NPDR）的糖尿病患者毛细血管的层特异性视网膜血管反应性（RVR）。
使用先前描述的非呼吸装置向 41 名对照者和 22 名糖尿病患者（轻度或无 NPDR）同时输送室内空气、5%CO2 或 100%O2，同时获取黄斑中心 3x3mm2 扫频源光相干断层扫描血管造影（SS-OCTA）图像。为浅层视网膜层（SRL）和深层视网膜层（DRL）计算每种气体条件下的血管骨架密度（VSD）和血管直径指数（VDI）。浅层分析排除了小动脉和小静脉。使用协方差的混合因子分析对糖尿病状态进行分层，对所有模型进行调整，以适应年龄、性别和高血压。从事后比较中得出的多重比较的统计学意义定义为 p<0.017。
在对照组中，所有气体条件下毛细血管 VSD 存在显著差异（p<0.001）。这种差异存在于 SRL 和 DRL 中。在糖尿病患者中，SRL 对 CO2 条件无明显反应（p=0.072），DRL 对 CO2（p=0.9）和 O2 的反应迟钝（p=0.019）。在对照组的 SRL 中检测到毛细血管 VDI 的显著气体效应（p=0.001），这是由于氧气条件下的 VDI 高于二氧化碳条件。
糖尿病患者的 RVR 受损表现为 SRL 和 DRL 中对 CO2 的反常反应以及 DRL 中对 O2 的反应减弱。这些在糖尿病患者中出现的层和气体特异性损伤似乎发生在疾病的早期，主要发生在毛细血管水平。
