Hypertension in Africa Research Team (HART), Centre of Excellence, Faculty of Health Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
South African Medical Research Council, Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa.
Transl Stroke Res. 2019 Oct;10(5):485-494. doi: 10.1007/s12975-018-0673-4. Epub 2018 Nov 9.
Structural and functional similarities exist between the retinal, cerebral and, as previously suggested, the coronary microvasculature. Retinal microvascular structure and functionality (in response to flicker-light-induced-provocation (FLIP)) may relate to coronary artery disease risk and possible stroke risk. We investigated associations between retinal vessel structure, functionality and cardiac stress markers (cardiac troponin T [cTnT], amino-terminal B-type natriuretic peptide [NT-proBNP]) to translate these retina-heart relationships to stroke risk. We included 317 African and Caucasian teachers' (aged 23-68 years), who participated in the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study. Fasting plasma and serum samples for cTnT and NT-proBNP were collected. Retinal vascular calibres were quantified from fundus images and dynamic retinal vessel calibre responses during FLIP. The University of California stroke risk score was applied to assess sub-clinical 10-year stroke risk. cTnT levels were similar in Africans and Caucasians, whereas NT-proBNP levels were lower in Africans. In Africans, a reduced arteriolar calibre and attenuated arteriolar dilation during FLIP was associated with higher cTnT (p < 0.01). Their larger retinal-venular calibre (p < 0.02) and attenuated arteriolar dilation during FLIP (p < 0.05) were associated with lower NT-proBNP. Again, exclusively in Africans, increased cardiac stress, wider venular calibres and retinal arteriovenous nicking predicted an increased 10-year stroke risk with odds ratios of 1.57 (95% CI, 1.34; 1.68, p = 0.031), 1.51 (95% CI, 1.26; 1.59, p = 0.002), 1.10 (95% CI, 0.94; 2.85, p = 0.002) and 1.06 (95% CI 0.83; 1.56, p = 0.052), respectively. None of these associations were evident in the Caucasian group. Investigating the retinal vasculature may serve as a tool to approximate sub-clinical coronary and cerebral microvasculature damage or dysfunction. These cardiac stress-retinal associations additionally predicted a greater stroke risk in the SABPA African cohort. Observable changes in the retinal vasculature may serve as markers for the identification and prediction of cardio-systemic and cerebral vascular morbidities and risks, thereby establishing a brain-heart link. Graphical Abstract Proposed series of events during which sustained high pressure and increased cardiac stress may alter retinal reactivity and link to increased stroke risk.
视网膜、大脑和冠状动脉微血管之间存在结构和功能上的相似性。视网膜微血管的结构和功能（对闪烁光诱导的刺激（FLIP）的反应）可能与冠状动脉疾病风险和可能的中风风险有关。我们研究了视网膜血管结构、功能和心脏应激标志物（心脏肌钙蛋白 T [cTnT]、氨基末端 B 型利钠肽 [NT-proBNP]）之间的相关性，以将这些视网膜-心脏关系转化为中风风险。我们纳入了 317 名非洲裔和白种人教师（年龄 23-68 岁），他们参加了非洲人交感神经活动和动态血压研究（SABPA）。采集空腹血浆和血清样本用于检测 cTnT 和 NT-proBNP。从眼底图像中量化视网膜血管直径，并在 FLIP 期间测量动态视网膜血管直径反应。应用加利福尼亚大学中风风险评分评估亚临床 10 年中风风险。非洲裔和白种人之间的 cTnT 水平相似，而 NT-proBNP 水平在非洲裔中较低。在非洲裔中，小动脉直径减小和 FLIP 期间小动脉扩张减弱与 cTnT 升高相关（p<0.01）。他们较大的视网膜-小静脉直径（p<0.02）和 FLIP 期间小动脉扩张减弱（p<0.05）与 NT-proBNP 降低相关。同样，仅在非洲裔中，增加的心脏应激、更大的小静脉直径和视网膜动静脉吻合口预示着 10 年中风风险增加，优势比分别为 1.57（95%CI，1.34；1.68，p=0.031）、1.51（95%CI，1.26；1.59，p=0.002）、1.10（95%CI，0.94；2.85，p=0.002）和 1.06（95%CI 0.83；1.56，p=0.052）。这些关联在白种人群中均不明显。研究视网膜血管可能是一种评估亚临床冠状动脉和脑微血管损伤或功能障碍的工具。这些心脏应激-视网膜相关性进一步预测了 SABPA 非洲队列的中风风险增加。视网膜血管的可观察变化可能作为识别和预测心脏-系统性和脑血管疾病发病和风险的标志物，从而建立脑-心联系。示意图提出了一系列事件，在这些事件中，持续的高压和增加的心脏应激可能会改变视网膜的反应性，并与增加的中风风险相关联。
