Aqueous angiopoietin-like levels correlate with optical coherence tomography angiography metrics in diabetic macular edema
Authors:   Department of Ophthalmology, the First Affiliated Hospital of Xi&#x2019;an Jiaotong University, Xi&#x2019;an 710061, Shaanxi Province, China; Department of Ophthalmology, Yulin Hospital of Traditional Chinese Medicine, Yulin 719000, Shaanxi Province, China, Yan Jie , Qin Ya-Zhou ,   Department of Ophthalmology, the First Affiliated Hospital of Xi&#x2019;an Jiaotong University, Xi&#x2019;an 710061, Shaanxi Province, China, Qiu Xuan-Yu ,   Department of Ophthalmology, the First Affiliated Hospital of Xi&#x2019;an Jiaotong University, Xi&#x2019;an 710061, Shaanxi Province, China, Qin Li ,   Department of Ophthalmology, the First Affiliated Hospital of Xi&#x2019;an Jiaotong University, Xi&#x2019;an 710061, Shaanxi Province, China, Li Jing-Ming ,   Department of Ophthalmology, the First Affiliated Hospital of Xi&#x2019;an Jiaotong University, Xi&#x2019;an 710061, Shaanxi Province, China
Published: November 2021

AIM: To quantitatively detect aqueous levels of angiopoietin-like (ANGPTL)3, ANGPTL4, and ANGPTL6 and investigate their correlation with optical coherence tomography angiography (OCTA) findings in patients with diabetic macular edema (DME).
METHODS: This cross-sectional study included 23 patients (27 eyes) with type 2 diabetes and 16 control subjects (20 eyes). All patients underwent OCTA imaging and ultra-wide field fundus photography. Diabetic patients were categorized into two groups according to the presence or absence of diabetic retinopathy (DME group, 14 patients, 16 eyes); and non-diabetic retinopathy (NDR) group, 9 patients, 11 eyes, respectively. Aqueous levels of ANGPTL3, ANGPTL4, and ANGPTL6 were assessed using suspension array technology, and foveal-centered 3×3 mm2 OCTA scans were automatically graded to determine the central, inner, and full vessel density (CVD, IVD, FVD); central, inner, and full perfusion density (CPD, IPD, FPD), foveal avascular zone (FAZ) area, FAZ perimeter, and FAZ circularity index (FAZ-CI) on superficial capillary plexuses. Additionally, central subfield thickness (CST), cube volume (CV), and cube average thickness (CAT) were measured in a model of macular cube 512×128.
RESULTS: Aqueous ANGPTL3 levels were not significantly different among the three groups (P>0.05). ANGPTL4 levels were significantly higher in the DME group than the control and NDR groups (P<0.0001 and P<0.001), while ANGPTL6 levels were significantly higher in the DME group than the control group (P<0.05). In the whole cohort, the aqueous ANGPTL3 levels correlated negatively with the IVD, FVD, IPD, and FPD, and positively with the CV and CAT. The aqueous ANGPTL4 levels correlated negatively with the CVD, IVD, FVD, CPD, IPD, and FPD, and positively with the FAZ perimeter, CST, CV, and CAT. The aqueous ANGPTL6 levels correlated negatively with the IVD, FVD, IPD, FPD, FAZ-CI and positively with CST, CV, CAT.
CONCLUSION: ANGPTL4 and ANGPTL6 may be associated with vascular leakage in DME and may represent good targets for DME therapy. In addition, OCTA metrics may be useful for evaluating macular ischemia in DME.