Horstmann Jens, Schulz-Hildebrandt Hinnerk, Bock Felix, Siebelmann Sebastian, Lankenau Eva, Hüttmann Gereon, Steven Philipp, Cursiefen Claus
Department of Ophthalmology, University of Cologne, Cologne, Germany.
Cluster of Excellence: Cellular Stress Responses in Aging-associated Diseases (CECAD), University of Cologne, Cologne, Germany.
Invest Ophthalmol Vis Sci. 2017 Nov 1;58(13):5880-5886. doi: 10.1167/iovs.17-22286.
Corneal neovascularization, in particular lymphangiogenesis, is a limiting factor in corneal transplant survival. Novel treatment approaches focus on (selective) inhibition and regression of lymphatic vessels. Imaging clinically invisible corneal lymphatic vessels is a prerequisite for these strategies. Using a murine model, this study investigates whether corneal lymphatic vessels can be imaged using microscopic optical coherence tomography (mOCT).
Corneal neovascularization was induced by intrastromal placement of 11.0 nylon sutures in one eye of BALB/c mice. After 2 weeks, cross-sectional images and volumes of the corneas with a 0.5 mm lateral and axial field of view were acquired using a custom-built mOCT system enabling a resolution of 1 μm at a B-scan rate of 165/s. Three of the six animals received an additional intrastromal injection of India ink 24 hours before the measurement to stain the corneal lymphatic system in vivo. Immunohistochemistry using CD31 and LYVE-1 was used to validate the mOCT findings.
Using mOCT, lymphatic vessels were visible as dark vessel-like structures with the lumen lacking a hyperreflective wall and mostly lacking cells. However, individual, slowly moving particles, which most likely are immune cells, occasionally could be observed inside the lumen. In lymphatic vessels of ink-stained corneas, hyperreflection and shadowing underneath was observed. Ink-filled lymphatic vessels were colocalized in consecutive corneal flat mounts of the same specimen.
Corneal lymphatic vessels can be imaged using mOCT. This novel approach opens new options for noninvasive clinical imaging of corneal lymphatic vessels for diagnostic and therapeutic indications.
角膜新生血管形成，尤其是淋巴管生成，是角膜移植存活的限制因素。新型治疗方法聚焦于（选择性）抑制和消退淋巴管。对临床上不可见的角膜淋巴管进行成像，是这些治疗策略的前提条件。本研究利用小鼠模型，探究是否可通过显微光学相干断层扫描（mOCT）对角膜淋巴管进行成像。
在BALB/c小鼠的一只眼睛中，通过基质内植入11.0尼龙缝线诱导角膜新生血管形成。2周后，使用定制的mOCT系统采集角膜的横截面图像和体积，该系统在横向和轴向视野为0.5 mm时，能够以165/s的B扫描速率实现1μm的分辨率。6只动物中有3只在测量前24小时接受了额外的基质内印度墨汁注射，以便在体内对角膜淋巴系统进行染色。使用CD31和LYVE-1进行免疫组织化学分析，以验证mOCT的结果。
使用mOCT，淋巴管可呈现为暗的血管样结构，管腔内缺乏高反射壁且大多没有细胞。然而，偶尔可在管腔内观察到单个的、移动缓慢的颗粒，极有可能是免疫细胞。在墨汁染色角膜的淋巴管中，观察到下方有高反射和阴影。充满墨汁的淋巴管在同一样本连续的角膜平铺标本中定位一致。
可通过mOCT对角膜淋巴管进行成像。这种新方法为角膜淋巴管的非侵入性临床成像开辟了新的选择，可用于诊断和治疗目的。
