天然药物在后发性白内障治疗的研究进展

后发性白内障(posterior capsular opacification,PCO)是现代白内(?)术后最常见的并发症之一。晶状体囊膜残留的晶状体上皮细胞的增殖、迁移、纤维化生是形成后发性白内障的主要原因。目前防治后发障的研究主要集中在药物除去或破坏残留晶状体上皮细胞。天然药物以其较低的毒副作用,已经成为药物防治PCO的研究热点之一。本文就天然药物对于PCO的防治的研究进行综述。     

药物预防后发性白内障的研究进展

目的 后发性白内障是现代白内障囊外摘除术后的最主要并发症,术后残留的晶状体上皮细胞的增殖、迁移、纤维化生是形成后发性白内障的主要原因.以往研究了多种抑制后发障的药物,尽管作用机制各不相同,但主要为促进细胞凋亡,因其安全性而未在临床应用.近几年的研究重点则侧重于通过不同途径抑制晶状体上皮细胞的增殖和迁移,与以往研究药物的出发点截然不同.此文就近几年研究较多的药物及相关作用机制作一综述.     

不同的给药途径防治后发性白内障

后发性白内障是白内障囊外摘出联合人工晶状体植入术后最常见的并发症,术后残留的晶状体上皮细胞是其发生的关键因素,防治后发性白内障最重要问题是抑制晶状体上皮细胞增殖和迁移,这类似于肿瘤的治疗,因此,选择最佳给药途径以维持药物有效浓度并减少其毒副作用,是研究的难点,我们就防治后发性白内障的药物的给药途径进行综述。     

密封囊袋冲洗装置在后发性白内障防治中的应用

后发性白内障仍是导致白内障患者术后再次失明的主要原因.理论上说,使用药物彻底清除残留于晶状体囊袋内的晶状体上皮细胞将是预防后发性白内障最直接的方法.封闭囊袋灌洗系统的问世使药物防治后发性白内障成为可能.本文对封闭囊袋灌洗系统在后发性白内障中的应用进行综述如下.     

后发性白内障的研究进展

后发性白内障（posterior capsule opacification,PCO）是由于白内障术后残留的晶状体上皮细胞增殖、迁移、化生而形成的,严重影响术后视力的恢复,是现代白内障囊外摘出术后主要的并发症之一.因此,如何防治PCO一直是眼科研究的热点之一.本文就临床及实验室药物防治PCO两方面进行综述.     

后发性白内障防治的研究

后发性白内障的发生与患者手术时的年龄,囊袋的大小,囊口的连续性,血房水屏障破坏释放的炎症介质,残留的晶状体上皮细胞移行分化及晶状体皮质的多少,以及所植入的人工晶状体的材质等因素有关。后发性白内障是白内障术后最常见的并发症,是白内障术后视力下降的主要原因。本文就后发性白内障的防治对策综述如下。     

结缔组织生长因子与后发性白内障的研究进展

后发性白内障(又称后囊膜混浊)已成为白内障术后视力再度下降,影响术后远期视力恢复的突出问题,主要是由于残留的晶状体上皮细胞向后囊膜移行、增殖形成。结缔组织生长因子(connective tissue growth factor,CTGF)是近年来倍受关注的促纤维化细胞因子。本文对近年来CTGF与后发性白内障关系的研究进展综述如下。     

后发性白内障的认识和防治

白内障是一种常见的致盲眼病 ,现代白内障囊外摘出或超声乳化术联合后房型人工晶状体植入术是当前治疗白内障的主要手段。但术后晶状体后囊浑浊即后发性白内障 (以下简称后发障 )的发生 ,会使术后提高的视力再度下降 ,影响手术效果。据文献报告 ,后发障的发生有 2个高峰 ,分别为术后 1年和 3年[1] ,其发生率儿童约为 95 8% [2～ 4] ,成人为 7 7%～ 41% [5] 。尤其是发生在儿童的后发障往往造成形觉剥夺性弱视 ,后果相当严重。因此 ,后发障的防治已日益受到人们的关注。(一 )病理生理在正常晶状体 ,上皮细胞限于前囊下、赤道部及赤道弓部 ,…     

后发性白内障

后发性白内障（简称后发障）是现代白内障囊外摘出手术后影响视力最常见的并发症，手术后残留的晶体上皮细胞增殖、生成新的晶体物质或／和纤维化生引起后囊皱缩而混浊。有学者观察了手术后晶体纤维再生的组织学过程，及生化因素对晶体上皮细胞增殖分化的影响，已经发现多种生长因子可影响晶体上皮细胞的有丝分裂活性。进一步研究术后早期晶体上皮细胞的增殖反应机制，对预防后发障的形成有特殊意义。     

后发性白内障预防的研究进展

后囊膜混浊是白内障囊外摘出联合人工晶状体植入术后最常见的并发症，术后残留的晶状体上皮细胞是其发生的关键因素。近年来国内外学者不断从手术方式的改进、人工晶状体的相关因素、囊袋张力环及染料对晶状体上皮细胞的影响、密封囊灌洗技术的应用等方面来防治后发性白内障，本文主要对近几年的研究进展加以综述。     

Posterior capsule opacification

Posterior capsule opacification (PCO) is the most common complication following primary cataract surgery. Advances in intraocular lens (IOL) designs that have reduced the amount of PCO following surgery have been made. The understanding of how the IOL design effects PCO has also advanced. Lenses that provide a mechanical barrier between it and the posterior lens capsule seem to inhibit PCO to a greater degree. Intracapsular rings are now being explored to test and enhance this barrier effect. Major advances in the elimination of lens epithelial cells at the time of surgery especially by pharmacologic means have also been made. An immunotoxin specific for human lens epithelial cells shows promise and is under latter phase clinical development.     

Pharmacological attempts to reduce posterior capsule opacification after cataract surgery – a review

Reduction of posterior capsule opacification (PCO) after cataract surgery has been achieved since the general acceptance of posterior chamber intraocular lens implantation 30 years ago. Attention to surgical technique on the one hand and changes in lens design and materials on the other have synergistically reduced the incidence of PCO to less than 5% at 5 years. But lens epithelial cells still proliferate and pharmacological prevention has been largely unsuccessful so far. Any agent must be toxic to these lens epithelial cells without being toxic to the corneal endothelium. This review looks at many substances that have been tried and a few that have been partly successful without yet entering clinical practice. Possibilities for future clinical research are canvassed.     

Posterior capsule opacification in pseudophakic eyes--etiopathogenesis, clinical picture, possibilities of prevention and therapy

Posterior capsule opacification (PCO) is a late complication after the cataract surgery, currently occurring most often. The epithelial cells which migrate to the surface of the posterior capsule participate in the mechanism of PCO formation. Clinical opacification of the posterior capsule appears as the foggy form, creasing, pearl mass and fibrosis. PCO can be cured by laser or surgical capsulotomy. The factors influencing a size and intensity of PCO are as follows: age of patient, other diseases, method of surgery and type of the implanted artificial intraocular lens. Prevention against PCO during surgery should include accurate hydrodissection, removing of cortical mass, polishing of the capsule and intracapsular fixation of the lens. It is necessary to carry out further studies on possibilities of PCO prevention.     

靶向治疗后囊混浊的研究进展

后囊混浊是白内障手术的常见并发症。残留晶状体上皮细胞在后囊的增殖、移行、纤维化生是后囊混浊形成的重要因素。用于防治后囊混浊的许多约物如道诺霉素、丝裂霉素等，因眼内的毒副作用而受到限制。靶向治疗的特异性、针对性为解决这一问题带来了希塑。综述了靶向治疗后囊混浊的研究现状及对未来的研究展望。     

Posterior capsule opacification: What's in the bag?

Cataract, a clouding of the lens, is the most common cause of blindness in the world. It has a marked impact on the wellbeing and productivity of individuals and has a major economic impact on healthcare providers. The only means of treating cataract is by surgical intervention. A modern cataract operation generates a capsular bag, which comprises a proportion of the anterior capsule and the entire posterior capsule. The bag remains in situ, partitions the aqueous and vitreous humours, and in the majority of cases, houses an intraocular lens (IOL). The production of a capsular bag following surgery permits a free passage of light along the visual axis through the transparent intraocular lens and thin acellular posterior capsule. Lens epithelial cells, however, remain attached to the anterior capsule, and in response to surgical trauma initiate a wound-healing response that ultimately leads to light scatter and a reduction in visual quality known as posterior capsule opacification (PCO). There are two commonly-described forms of PCO: fibrotic and regenerative. Fibrotic PCO follows classically defined fibrotic processes, namely hyperproliferation, matrix contraction, matrix deposition and epithelial cell trans-differentiation to a myofibroblast phenotype. Regenerative PCO is defined by lens fibre cell differentiation events that give rise to Soemmerring's ring and Elschnig's pearls and becomes evident at a later stage than the fibrotic form. Both fibrotic and regenerative forms of PCO contribute to a reduction in visual quality in patients. This review will highlight the wealth of tools available for PCO research, provide insight into our current knowledge of PCO and discuss putative management of PCO from IOL design to pharmacological interventions.     

Cerulean posterior capsule opacity

We present a case of light-blue posterior capsule opacification (PCO) in a patient who had cerulean cataracts removed 1 year earlier. The color of the PCO was similar to that of the cerulean cataracts prior to extraction. Posterior capsule opacification is a common complication after cataract surgery; however, we could not find a similar case of cerulean posterior capsule opacity in the literature. The findings in this case suggest that the mechanism of the light-blue color formation in the cataract was also present in the lens epithelial cells forming the posterior capsule opacity.     

Retrovirus-mediated transfer of a suicide gene into lens epithelial cells in vitro and in an experimental model of posterior capsule opacification.

PURPOSE. The most common complication of cataract surgery is the development of posterior capsule opacification (PCO). Hyperplasia of the lens epithelium is one of the main cellular events following phacoemulsification and was found to be an important feature contributing to opacification of the posterior capsule. We investigated the feasibility of killing the residual lens epithelial cells by retroviral-mediated transfer of the herpes simplex virus-thymidine kinase (HSV-tk) gene, a well-studied suicide gene, into rabbit lens epithelial cells followed by ganciclovir (GCV) treatment. METHODS. The capacity of retroviral vectors to transfer genes into rabbit lens epithelial cells was determined either in vitro (culture of rabbit lens epithelial cells) or in vivo (experimental model of PCO in rabbits) using cDNA encoding the beta-galactosidase (LacZ) reporter gene. To evaluate the efficiency of suicide gene therapy (infection with retroviral vectors encoding the HSV-tk gene followed by GCV treatment) we determined the sensitivity of HSV-tk infected lens epithelial cells to different concentrations of GCV in vitro. Then, in an experimental model of PCO, rabbits were treated with HSV-tk retroviral vectors at the end of the surgery and they received repeated intracameral and intravitreal injections of GCV at the concentration determined by the in vitro experiments. RESULTS. Infection efficiency using LacZ retroviral vectors was about 29% in vitro and 10% in vivo. After infection of the HSV-tk cDNA in vitro, the cell killing effect of GCV was evaluated. A significant enhancement (four- to five-fold) of the cell sensitivity to GCV was shown in FLY-DFGtk as compared with mock infected (P < 0.01) cells even without selection of the HSV-tk positive cells. The GCV concentration leading to 50% reduction in cell number (IC50) was 50 microg/ml. In vivo infection with a HSV-tk vector led to the tk gene transfer into lens epithelial cells. Despite this local HSV-tk gene expression, we could not prevent capsule opacification. CONCLUSIONS. Lens epithelial cells were successfully infected both in vitro and in vivo by beta-galactosidase and HSV-tk genes via retroviral vectors. In vitro infected lens epithelial cells displayed a strong sensitivity to GCV treatment. In vivo, we could not prevent capsule opacification in the rabbit model, very likely due to the limited level of the HSV-tk gene expression. However, our results suggest that virus-mediated suicide gene therapy might be a feasible treatment strategy to prevent capsule opacification with a more powerful vector.     

后发性白内障的生物靶向治疗

后发性白内障是白内障摘出术后或晶状体外伤后,残留的皮质或晶状体上皮细胞( LECs)增生形成的混浊,又称后囊膜混浊,是白内障摘出术后最常见的并发症,亦是白内障患者术后视力下降的主要原因.国内外研究表明,术后LECs的残留和增生是后发性白内障发生、发展的关键因素.关于如何有效地防治后发性白内障一直是眼科学者关注的焦点,包括药物治疗、激光治疗和手术治疗.近年来,其生物靶向治疗成为国内外学者研究的热点,包括一些抗LECs增生药物的局部应用或通过制备转染抗LECs抗体和免疫毒素的载体以抑制LECs的增生或基因治疗等.就近十年来相关研究的进展及发展趋势进行综述.     

Posterior capsule opacification and anterior capsule opacification

Posterior capsule opacification (PCO) is still the most frequent complication of cataract surgery. A variety of studies has led to a better understanding of the pathogenesis of PCO, and strategies of molecular biology have produced new therapeutic options, such as immunological techniques or gene therapeutic approaches. Surgical strategies and intra-ocular lens-dependent factors also are capable to reduce the rate of PCO. In-the-bag implantation of intra-ocular lenses with a sharp optic edge seems to be effective in inhibiting equatorial lens epithelial cell migration to the center of the posterior capsule. Several PCO documentation systems have been developed that will lead to more exact and better comparable recording of PCO rates. In the year 2000, PCO or secondary cataract is still the most frequent complication after extracapsular cataract surgery. In a 1998 meta-analysis, PCO rates of 11.8% 1 year after extracapsular cataract surgery with intraocular lens implantation, 20.7% after 3 years, and 28.4 % after 5 years have been reported. For the United States, it has been estimated that the overall expenses for treatment of PCO are only exceeded by the costs for cataract treatment itself. In the past decade, a lot of experimental and clinical studies have been performed on this topic. They have led to 1) to a better understanding of the pathogenesis of the development of anterior and posterior capsule opacification; 2) more objective and better comparable systems of documentation and analysis of PCO; and a number of 3) surgical and 4) pharmaceutical strategies to prevent PCO.