Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology - Salzburg, Paracelsus Medical University, Salzburg, Austria; Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
Center for Anatomy and Cell Biology, Institute of Anatomy and Cell Biology - Salzburg, Paracelsus Medical University, Salzburg, Austria.
Ann Anat. 2021 Nov;238:151775. doi: 10.1016/j.aanat.2021.151775. Epub 2021 Jun 1.
The human choroid derives from the mesectoderm, except the melanocytes originating from the neuroectoderm. To date, it is unclear whether all choroidal melanocytes share the same origin or might have different origins. The purpose of this study was to screen immunohistochemically for mesenchymal elements in the adult healthy human choroid, in the malignant melanoma of the choroid, as well as in the developing human fetal choroid.
Human choroids were obtained from cornea donors and prepared as flat whole mounts for paraffin- and cryoembedding. Globes enucleated for choroidal melanoma and eyes from human fetuses between 11 and 20 weeks of gestation were also embedded in paraffin. Sections were processed for immunohistochemistry of the mesenchymal marker vimentin, the melanocyte marker Melan-A, and the macrophage marker CD68, followed by light-, fluorescence-, and confocal laser scanning-microscopy.
The normal choroid contained 499 ± 139 vimentin, 384 ± 78 Melan-A, and 129 ± 57 CD68 immunoreactive cells/mm. The vimentin immunopositive cell density was significantly higher than the density of Melan-A and CD68 immunopositive cells (p < 0.001, respectively). By confocal microscopy, 24 ± 8% of all choroidal melanocytes displayed vimentin immunoreactivity. In choroidal melanomas, numerous melanoma cells of the epithelioid and spindle cell type revealed immunopositivity for both vimentin and Melan-A. The intratumoral density of vimentin immunoreactive cells was 1758 ± 106 cells/mm, significantly higher than the density of Melan-A and CD68 immunopositive cells (p < 0.001, respectively). Comparing to healthy choroidal tissue, the choroidal melanomas revealed significantly higher densities of vimentin, Melan-A, and CD68 immunoreactive cells (p < 0.001, respectively). In the developing human fetal choroid, numerous vimentin and Melan-A immunopositive cells were detected not before the 16th week of gestation, with some of them showing colocalization of vimentin and Melan-A.
The adult healthy human choroid is endowed with a significant number of vimentin immunopositive mesenchymal structures, including a subpopulation of vimentin immunoreactive choroidal melanocytes. These vimentin immunopositive melanocytic cells are also present in choroidal melanomas as well as in the developing human fetal choroid. Therefore, different embryologic origins can be considered for choroidal melanocytes.
脉络膜来源于中胚层，除了起源于神经外胚层的黑色素细胞。迄今为止，尚不清楚所有脉络膜黑色素细胞是否具有相同的起源，或者它们可能具有不同的起源。本研究的目的是筛选成人健康脉络膜、脉络膜恶性黑色素瘤和发育中的人胎脉络膜中的间充质成分。
从角膜供体中获得脉络膜，并制备为用于石蜡和冷冻包埋的扁平全铺片。脉络膜黑色素瘤切除的眼球和妊娠 11 至 20 周的人胎眼也被包埋在石蜡中。对间充质标志物波形蛋白、黑色素细胞标志物 Melan-A 和巨噬细胞标志物 CD68 进行免疫组织化学处理，然后进行光镜、荧光镜和共聚焦激光扫描显微镜检查。
正常脉络膜含有 499±139 个波形蛋白、384±78 个 Melan-A 和 129±57 个 CD68 免疫反应性细胞/mm。波形蛋白免疫阳性细胞密度明显高于 Melan-A 和 CD68 免疫阳性细胞密度（分别为 p<0.001）。通过共聚焦显微镜，24±8%的脉络膜黑色素细胞显示波形蛋白免疫反应性。在脉络膜黑色素瘤中，许多上皮样和纺锤形细胞类型的黑色素瘤细胞对波形蛋白和 Melan-A 均呈免疫阳性。肿瘤内波形蛋白免疫阳性细胞的密度为 1758±106 个细胞/mm，明显高于 Melan-A 和 CD68 免疫阳性细胞的密度（分别为 p<0.001）。与健康脉络膜组织相比，脉络膜黑色素瘤显示出更高密度的波形蛋白、Melan-A 和 CD68 免疫反应性细胞（分别为 p<0.001）。在发育中的人胎脉络膜中，在妊娠 16 周之前没有检测到大量的波形蛋白和 Melan-A 免疫阳性细胞，其中一些细胞显示波形蛋白和 Melan-A 的共定位。
成人健康脉络膜具有大量的波形蛋白免疫阳性间充质结构，包括一群波形蛋白免疫阳性的脉络膜黑色素细胞。这些波形蛋白免疫阳性的黑色素细胞也存在于脉络膜黑色素瘤以及发育中的人胎脉络膜中。因此，脉络膜黑色素细胞可以考虑具有不同的胚胎起源。
