Lee Yih-Jing, Chiu Chien-Chao, Ke Chia-Ying, Tien Ni, Lin Po-Kang
School of Medicine, Fu-Jen Catholic University, Hsinchuang, New Taipei City, Taiwan.
Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan.
Invest Ophthalmol Vis Sci. 2017 Aug 1;58(10):4332–4343. doi: 10.1167/iovs.17-22308.
To investigate the effects of homocysteine on choroidal angiogenesis, we established an ex vivo choroidal sprouting explant model and examined the potential growth factors for angiogenesis.
Choroid fragments with retinal pigment epithelium were isolated from mouse and embedded in Matrigel. Homocysteine at different concentrations were added to the culture mediums. The choroidal explants were observed at different time points, and the total area of choroidal sprouting was measured and analyzed.
Homocysteine evoked choroidal capillary sprouting by inducing capillary endothelial cell proliferation with pericyte formation and by facilitating polygonal angiogenetic networks. In some cases, vascular lumens were observed in the newly forming capillaries facilitated by homocysteine. The choroidal sprouting effect of homocysteine can only be observed at a certain range of homocysteine concentration, with 1-mM homocysteine exhibiting the most significantly increased choroidal sprouting areas. Isolectin overexpression was noted in the homocysteine-treated group. Possible growth factors for angiogenesis were detected through immunofluorescent staining, which demonstrated the overexpression of platelet-derived growth factor C and angiopoietin 1 in the homocysteine-treated preparations only. In these preparations, platelet-derived growth factor C was highly expressed in the tip cells of sprouting capillaries.
We therefore conclude that platelet-derived growth factor C and angiopoietin 1 may play key roles in the choroid angiogenesis evoked by homocysteine.
为研究同型半胱氨酸对脉络膜血管生成的影响，我们建立了一种离体脉络膜发芽外植体模型，并检测了血管生成的潜在生长因子。
从小鼠中分离出带有视网膜色素上皮的脉络膜片段，并包埋于基质胶中。向培养基中添加不同浓度的同型半胱氨酸。在不同时间点观察脉络膜外植体，测量并分析脉络膜发芽的总面积。
同型半胱氨酸通过诱导毛细血管内皮细胞增殖并形成周细胞，以及促进多边形血管生成网络，引发脉络膜毛细血管发芽。在某些情况下，在同型半胱氨酸促进形成的新毛细血管中观察到血管腔。同型半胱氨酸的脉络膜发芽效应仅在一定浓度范围内可观察到，1 mM同型半胱氨酸时脉络膜发芽面积增加最为显著。在同型半胱氨酸处理组中观察到异凝集素过表达。通过免疫荧光染色检测血管生成的可能生长因子，结果显示仅在同型半胱氨酸处理的标本中血小板衍生生长因子C和血管生成素1过表达。在这些标本中，血小板衍生生长因子C在发芽毛细血管的顶端细胞中高表达。
因此，我们得出结论，血小板衍生生长因子C和血管生成素1可能在同型半胱氨酸诱发的脉络膜血管生成中起关键作用。
