Sundaresan Yogapriya, Manivannan Lakshmi Priya, Radhakrishnan Shanthi, Ramasamy Krishnadas Subbiah, Veerappan Muthukkaruppan, Chidambaranathan Gowri Priya
Department of Immunology and Stem Cell Biology, Aravind Medical Research Foundation, Madurai, 625020, Tamil Nadu, India.
Department of Pathology, Aravind Eye Hospital and Post Graduate Institute of Ophthalmology, Madurai, 625020, Tamil Nadu, India.
Sci Rep. 2021 Dec 31;11(1):24518. doi: 10.1038/s41598-021-03345-1.
We previously identified and characterized human trabecular meshwork stem cells (TMSCs) based on high expression of ABCG2/p75 positivity and high nucleus to cytoplasmic ratio. These TMSCs expressing high ABCG2 and p75 were located to the insert region of the human TM. Additionally, we demonstrated an age-related reduction in the TMSC content which was significantly associated with TM cell loss. In continuation, this study was aimed to determine the TMSC content in glaucomatous donor eyes wherein a drastic reduction in TM cellularity has already been reported. Anterior segments from known glaucomatous (n = 6) and age-matched normal (n = 8) donors were dissected into four quadrants. A minimum of three sections from each quadrant were used for histopathological analysis as well as immunostaining. Analysis of hematoxylin and eosin-stained sections from glaucomatous tissues revealed a decrease in total TM cellularity, thickening of trabecular beams, fusion of trabeculae, absence of patent Schlemm's canal compared to age-matched controls. In addition, the TM thickness at various positions of the meshwork and the coronal as well as the meridional diameters of the Schlemm's canal were observed to be significantly reduced in glaucomatous eyes. Further, sections from both the groups were immunostained for universal stem cell marker ABCG2 and neural crest derived stem cell marker p75. The images were acquired using Leica SP8 confocal microscope. Quantification of total TM cellularity based on nuclear counterstain (mean ± SD) using ImageJ identified 69.33 ± 12.77 cells/section in control eyes. In glaucomatous donors, the TM cellularity was found to be reduced significantly to 41.83 ± 9.0 (p = 0.0007). In addition, a reduction in the percentage of TMSCs (cells with high ABCG2 expression and p75 positivity) was evident in glaucomatous donors (0.14 ± 0.17%) compared to age-matched controls (4.73 ± 5.46%) (p = 0.064). Thus, the present study confirmed the significant decline in TM cellularity and a reducing trend in the TMSC content, though this reduction was non-significant in glaucomatous donor eyes. Further studies are essential to elucidate the role of TMSCs in the pathogenesis of primary open angle glaucoma.
我们之前基于ABCG2高表达/p75阳性以及高核质比鉴定并表征了人小梁网干细胞（TMSCs）。这些高表达ABCG2和p75的TMSCs定位于人小梁网的插入区域。此外，我们证明了TMSC含量随年龄减少，这与小梁网细胞丢失显著相关。接下来，本研究旨在确定青光眼供体眼中的TMSC含量，其中已有报道小梁网细胞数量急剧减少。将已知青光眼患者（n = 6）和年龄匹配的正常供体（n = 8）的眼前节解剖为四个象限。每个象限至少取三个切片用于组织病理学分析和免疫染色。对青光眼组织苏木精和伊红染色切片的分析显示，与年龄匹配的对照组相比，小梁网总细胞数量减少、小梁束增厚、小梁融合、施莱姆管无开放。此外，观察到青光眼眼中小梁网不同位置的厚度以及施莱姆管的冠状和子午线直径均显著减小。此外，对两组切片进行通用干细胞标志物ABCG2和神经嵴衍生干细胞标志物p75的免疫染色。使用徕卡SP8共聚焦显微镜采集图像。使用ImageJ基于核复染（平均值±标准差）对小梁网总细胞数量进行定量分析，发现对照眼中每切片有69.33±12.77个细胞。在青光眼供体中，小梁网细胞数量显著减少至41.83±9.0（p = 0.0007）。此外，与年龄匹配的对照组（4.73±5.46%）相比，青光眼供体中TMSCs（高表达ABCG2且p75阳性的细胞）的百分比明显降低（0.14±0.17%）（p = 0.064）。因此，本研究证实了小梁网细胞数量显著下降以及TMSC含量呈减少趋势，尽管在青光眼供体眼中这种减少不显著。进一步的研究对于阐明TMSCs在原发性开角型青光眼发病机制中的作用至关重要。
