Transforming ocular surface stem cell research into successful clinical practice

It has only been a quarter of a century since the discovery of adult stem cells at the human corneo-scleral limbus. These limbal stem cells are responsible for generating a constant and unending supply of corneal epithelial cells throughout life, thus maintaining a stable and uniformly refractive corneal surface. Establishing this hitherto unknown association between ocular surface disease and limbal dysfunction helped usher in therapeutic approaches that successfully addressed blinding conditions such as ocular burns, which were previously considered incurable. Subsequent advances in ocular surface biology through basic science research have translated into innovations that have made the surgical technique of limbal stem cell transplantation simpler and more predictable. This review recapitulates the basic biology of the limbus and the rationale and principles of limbal stem cell transplantation in ocular surface disease. An evidence-based algorithm is presented, which is tailored to clinical considerations such as laterality of affliction, severity of limbal damage and concurrent need for other procedures. Additionally, novel findings in the form of factors influencing the survival and function of limbal stem cells after transplantation and the possibility of substituting limbal cells with epithelial stem cells of other lineages is also discussed. Finally this review focuses on the future directions in which both basic science and clinical research in this field is headed.     

角膜缘干细胞移植治疗翼状胬肉切除联合羊膜移植术后羊膜溶解

目的：观察角膜缘干细胞移植术治疗翼状胬肉切除联合羊膜移植术后羊膜溶解的临床效果。方法：翼状胬肉切除术联合羊膜移植术后出现羊膜溶解的患者124例135眼随机分成A、B、C三组,A组36例38眼采取保守治疗, B组42例45眼再次行羊膜移植术, C组46例52眼行自体角膜缘干细胞移植术。术后随访6～18mo比较各组胬肉复发情况。结果：A组38眼中24眼复发,复发率63．2％。 B组45眼中术后7眼胬肉复发,复发率15．6％。 C组52眼2眼复发,复发率3．8％,A组与B组比较,B组与C组比较差异均有统计学意义（P＜0．05）。结论：自体角膜缘干细胞移植术是治疗翼状胬肉切除联合羊膜移植术后羊膜溶解的有效方法。     

In vivo confocal microscopy of congenital aniridia-associated keratopathy

Purpose

To explore the in vivo morphological changes of cornea and limbus in aniridia-associated keratopathy (AAK).

Methods

Three cases of AAK were examined with the application of in vivo confocal microscopy (IVCM).

Results

Abnormal structure of wing and basal layer of epithelium, the loss of subbasal nerves, and the presence of goblet cells at central cornea could be identified in the most severe case, along with the absence of Vogt palisades. The less extent of abnormalities in corneal epithelial cells, subbasal nerve, and Vogt palisades were visible in the moderate or mild cases.

Conclusions

The morphological changes of cornea and limbus vary in AAK, and IVCM is a promising tool to determine the degree of limbal stem cell deficiency in patients with AAK.     

A new rat model of glaucoma induced by intracameral injection of silicone oil and electrocoagulation of limbal vessels

Background  A satisfied glaucoma model is absent now. The aim of this study was to evaluate the effect of a combination of intracameral injection of silicone oil and electrocoagulation of corneal limbal vessels and episcleral veins in the rats to establish glaucoma model.

Methods  Operation was performed in each of the left eyes of 90 adult male rats. Right eyes were used as controls. Measurement of intraocular pressure (IOP) was performed with an applanation tonometer (Tono-Pen). Retinal ganglion cells (RGCs) were retrogradely labeled by applying FluoroGold onto the bilateral superior colliculus.

Results  During the follow-up (24 weeks), the IOP of the study eyes was significantly higher (P <0.05) than the control eyes (at final examination, IOP of control eyes was (13.4±1.0) mmHg and IOP of study eyes was (16.1±1.8) mmHg). Correspondingly, at 24 weeks after operation, the RGCs density of the study eyes (2286.11±290.45/mm²) was significantly lower than the control eyes (2626.46±164.85/mm², P <0.01). In the operated eyes, histological examination showed excavation of optic disc and increased neuroglial cells in the optic nerve, reduced thickness of retina and diminution of retinal ganglion cells, and atrophy of ciliary body and iris. Notably, the anterior chamber angle of the operated eye remained open.

Conclusions  A combination of intracameral injection of silicone oil and electrocoagulation of corneal limbal vessels and episcleral veins may establish a reliable glaucoma model for further research.

     

翼状胬肉切除联合自体角膜缘干细胞移植治疗翼状胬肉的疗效观察

目的观察翼状胬肉切除联合自体角膜缘干细胞移植治疗翼状胬肉的临床疗效。方法将80例(92眼)翼状胬肉患者随机分为治疗组38例(45眼)和对照组42例(47眼)。对照组采用传统胬肉切除治疗,治疗组采用翼状胬肉切除联合自体角膜缘干细胞移植治疗。比较2组角膜上皮愈合情况及术后复发情况。结果治疗组角膜上皮愈合速度显著快于对照组;且12个月内,治疗组复发率为2.6%显著低于对照组的31.0%,差异有统计学意义(P<0.01)。结论翼状胬肉切除联合自体角膜缘干细胞移植治疗翼状胬肉疗效可靠,复发率低,无严重手术并发症,值得推广应用。     

间充质干细胞在角膜重建中的应用研究进展

角膜重建指的是各种外伤、炎症、变性性疾病引起的角膜上皮损伤、新生血管形成、角膜瘢痕等损伤之后,角膜结构完整性及角膜透明性的恢复。目前角膜重建的基础研究中,间充质干细胞逐渐成为研究的热点。本文对间充质干细胞在角膜重建中作用及进展予以综述,将为角膜重建的深入研究提供一定的参考资料。     

人角膜缘干细胞的体外培养及鉴定

目的探讨人自体角膜缘干细胞（LSCs）体外培养及鉴定的方法。方法将供体新鲜人角膜缘组织在制备的含20％胎牛血清DMEM／F12培养基的羊膜载体上应用组织块培养法进行体外培养,对培养获得的LSCs用苏木精-伊红染色在倒置显微镜下进行形态学观察,用免疫荧光技术鉴定培养的LSCs细胞。结果组织块静置2h后贴壁良好,3～4d细胞从组织块边缘荫出,7～10d细胞出现生长高峰,12～14d形成良好的细胞单层。细胞形态呈多边彤、圆形、卵圆形和梭形。第14天时行间接免疫荧光染色,可见大量细胞表达p63,呈细胞质的绿色荧光;少量细胞表达AE5,呈细胞质的绿色荧光和细胞核的红色荧光。结论组织块培养法体外培养的人LSCs具有与正常人LSCs相一致的生物学特性。     

表麻下角巩膜缘刺入法治疗IOL植入术后发性白内障

目的:探讨在表面麻醉情况下从角巩缘刺入进行针对白内障人工晶状体(IOL)术后后囊膜混浊划开与YAG激光后囊膜切开治疗方法对比。评价其临床效果及安全性及稳定性。方法:在表面麻醉下选择角巩缘用钻石刀刺入1mm,用自制弯形刺囊针深入人工晶状体后面对其增厚囊膜点状划开,观察临床效果及并发症。结果:患者29例32眼,划开前视力0.06～0.1,划开后视力1.0以上占69.9%,患者无任何不适,无任何并发症。结论:选用瑞士进口钻石刀在表面麻醉下角巩缘区刺开,方法简便易行,患者无任何不适,无任何并发症,达到立竿见影的效果,可以替代YAG激光的治疗。