Alteration of cadherin in dexamethasone-induced cataract organ-cultured rat lens

PURPOSE: A side effect associated with long-term treatment of various diseases with steroids is a high incidence of posterior subcapsular cataracts (PSC). To understand the mechanism underlying steroid-induced cataract, the cultured lens model was developed, and the expression of potential candidate proteins during opacity formation was examined. METHOD: Rat lenses were carefully dissected from the surrounding ocular tissue and incubated in medium 199. Dexamethasone was then added to the medium. The lenses were cultured for 7 days and photographed daily to record the development of opacity. Differential expression of candidate proteins was examined by Western blot analysis. RESULT: Various degrees of opacity were observed on the posterior subcapsular region as early as 5 days after incubation with dexamethasone. The expression of E-cadherin and N-cadherin decreased in the cultured rat lenses during the development of opacity. CONCLUSIONS: The pattern of opacity that developed in cultured rat lenses closely resembled that observed in patients with PSC. The results suggest that the decrease in E-cadherin plays a role in the formation of steroid-induced cataract.     

The role of lens epithelium in sugar cataract formation

Previous evidence has shown clearly that sugar cataract formation results from unusually high intracellular levels of polyol. Documentation of polyol-related histological changes in the cortical fiber cells of the equatorial zone has been extensive. However, little attention has been given to the early changes in the lens epithelial cells, in spite of the fact that the highest level of aldose reductase is found in this layer of the lens. Also, cultured lens epithelial cells exposed to high sugar levels exhibit rapid accumulation of polyol and show ultrastructural alterations. Therefore, a study was designed to evaluate the role of the lens epithelium in sugar cataract formation. Specifically, an attempt was made to localize the earliest fine structural lesions in intact lenses of galactose-fed rats and to test their relation to aldose reductase. Rats were fed either a normal diet or a 50% galactose diet with or without sorbinil, an aldose reductase inhibitor. Rats were killed at varying periods of time ranging from 6 to 96 hr, and the eyes were processed for light and electron microscopy. The first detectable abnormalities occurred after 36 hr of galactose feeding, and were limited to the central lens epithelium. Cell edema, apparent dilution of cytoplasm, rounding of nuclei, aberrant intracellular vacuoles, and loss of normal tortuosity of cell boundaries were the salient lesions. No changes were detectable in the equatorial zone until 48 hr, and no deviation from the control structure was found in any of the rats treated with an aldose reductase inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)     

Iris-ciliary complex inhibits protein synthesis by organ cultured mammalian ocular lens cells

Freshly isolated rabbit ocular lenses with or without adhering iris-ciliary complex were organ cultured. It was found that lenses with iris-ciliary complex showed decreased protein synthetic ability. Vimentin, a cytoskeletal protein and MP-26, a membrane associated protein, were used as markers for protein synthetic activity. Removal of the iris-ciliary complex at least partially restores the protein synthetic capability of the lens. The ocular lenses cultured with iris-ciliary complex for 48 hr showed marked equatorial opacities.     

Primary cataract extraction and intraocular lens implantation in penetrating ocular trauma

PURPOSE: To analyze the postoperative outcome and complication rate after cataract extraction or lensectomy with primary intraocular lens (IOL) implantation for penetrating traumatic cataract. DESIGN: Retrospective, nonconsecutive, noncomparative case series. METHODS: We retrospectively reviewed the files of 21 patients who were admitted to our departments because of traumatic cataract with corneal or scleral laceration caused by penetrating trauma with or without intraocular foreign body (IOFB) from 1992 through 1997. Lens aspiration or manual extracapsular cataract extraction with primary IOL implantation was performed in all patients. Removal of an IOFB was performed in eight patients. MAIN OUTCOME MEASURES: Final visual acuity and deviation of actual refraction from emmetropia and from expected postoperative refraction. RESULTS: The mean follow-up was 20.4 months. Fourteen eyes (67%) achieved final visual acuity of 20/40 or better, 95% obtained 20/60 or better final visual acuity, and all eyes achieved 20/100 or better final visual acuity. Major causes of limited visual acuity were central corneal scar and central retinal injury. Eleven eyes (57%) experienced secondary cataract and underwent neodymium:yytrium-aluminum-garnet capsulotomy. CONCLUSIONS: Primary implantation of posterior chamber lenses after penetrating ocular trauma is associated with favorable visual outcome and a low rate of postoperative complications.     

Effect of vitamin E-containing liposome on experimental sugar cataract

The effect of vitamin E-containing liposome on experimental sugar cataract formation in vitro was investigated. The lenses of male Wistar rats aged 6 weeks were prepared by incubating with 55. 6 mM glucose with vitamin E-containing liposome (dipalmitoyl phosphatidylcholine: DPPC). We examined the formation of lens opacity and assayed vitamin E and its related compounds. Incubation with vitamin E-containing liposome prevented sugar cataract formation. In Addition, vitamin E concentration in lens was significantly elevated by incubation with vitamin E-containing liposome. In lenses of the high level glucose group incubated without vitamin E-containing liposome, lipid peroxide (LPO) content was increased, but in lenses of the high-level glucose group incubated with vitamin E-containing liposome the increase was significantly inhibited at each incubation time. Vitamin E had no effect either on the decrease of reduced glutathione (GSH) or the increase of sorbitol content in lens incubated with high level glucose medium. In conclusion vitamin E-containing liposome was transported from medium to lens well and was significantly effective in preventing experimental sugar cataract formation in vitro. The protective effects of vitamin E are probably caused not only by its antioxidative action.     

Dynamic profile of ocular refraction in pediatric cataract patients after lens surgeries

AIM: To study the change in ocular refraction in patients with pediatric cataracts (PCs) after lens extraction. METHODS: A total of 1258 patients who were undergoing cataract extraction with/without intraocular lens (IOL) implantation were recruited during preoperative examinations between Jan 2010 and Oct 2013. Patient ages ranged from 1.5mo to 14y. Follow-ups were conducted at 1wk, 1, and 3mo postoperatively and every 3mo in the first year, then 6mo thereafter. Ocular refraction [evaluated as spherical equivalent (SE)] and yearly myopic shift (YMS) were recorded and statistically analyzed among patients with age at surgery, baseline ocular refraction, gender, postoperative time and laterality (bilateral vs unilateral). RESULTS: By Dec 31st 2015, 1172 participants had been followed for more than 2y. The median follow-up period was 3y. The critical factors affecting the ocular refraction of PC patients were baseline ocular refraction, postoperative time for both aphakic and pseudophakic eyes. YMS grew most rapidly in young childhood and early adolescence. CONCLUSION: After lens surgeries, ocular refraction in PC patients shows an individual difference of change. Further concerns should be raising to monitor the rapid myopic shift at early adolescence of these patients.     

Detection of integrins in human cataract lens epithelial cells and two mammalian lens epithelial cell lines

AIM: To compare the incidence of various integrin subunits in human cataract anterior lens epithelial cells (A-LEC) and in two mammalian LEC lines. METHODS: Circular sections of anterior capsules with attached LEC were obtained during cataract surgery. Integrin subunits were immunolocalised in these anterior LEC and in a human and rabbit LEC line, using four monoclonal antibodies specific for subunits alpha2, alpha3, and alpha5, and beta subunit 2. RESULTS: All of these subunits were found in at least a proportion A-LEC samples as follows: alpha2 71%, alpha3 92%, alpha5 62%, and beta2 24%. The human LEC line was immunoreactive for alpha2 and alpha3 only. The rabbit lens epithelial cell line was immunoreactive for alpha5 but there was no staining for alpha2, alpha3, or beta2. CONCLUSION: The A-LEC and mammalian LEC lines showed a similarity in their pattern of integrin expression. As these integrins are receptors for extracellular matrix (ECM) components, they are likely to be associated with the attachment and migration of LECs that precedes capsular opacification. Therefore these cell lines may be useful in the elucidation of mechanisms involved the pathogenesis of capsule opacification.     

Calcium-induced opacification and loss of protein in the organ-cultured bovine lens

A long-term system of organ culture for bovine lenses was used to investigate the effect of osmotic stress on lens opacification and crystallin loss. Lenses were pre-incubated in control medium containing L-[U-14C]tyrosine so that labelled crystallins were produced. The fate of these crystallins was studied in relation to two forms of osmotic stress. The addition of either ouabain or EGTA to the medium induced severe osmotic swelling and disturbance of the lens monovalent cation balance, but only the former treatment was followed by an increase in lens calcium. The changes due to osmotic stress were accompanied by loss of transparency and protein only in the lenses with increased calcium. Both opacification and increased calcium were found largely to be confined to the outer cortical fibres. Protein loss increased with time as lens calcium continued to increase. The protein recovered from the incubation medium was characterized by gel filtration and immunological techniques. The first protein detected was beta L-crystallin, and this formed the major part of the lost protein throughout, although alpha- and gamma-crystallins were detected at a later stage. Increased calcium also resulted in a change in the susceptibility of the crystallins to aggregation, since there was an increase in [14C]tyrosine incorporated into the lens high-molecular-weight (HM) fraction after exposure to ouabain, but not after exposure to EGTA. The relevance of these findings to human cataract is discussed.     

Studies on the use of desferrioxamine in experimental ocular siderosis produced by extrabulbar administration of iron

The objective of these studies was to find out whether iron administered extrabulbarly can penetrate inside the eyeball and whether this process can be checked by transconjunctival injections of desferrioxamine. Histological examination revealed that 12 months after the placing of iron in the orbit, an accumulation of the metal can be observed in the sclera, choroid, and retina of untreated animals. In the group of animals treated with desferrioxamine, iron did not penetrate into the eyeball, and only in some animals could its presence be found in superficial layers of the sclera. The possibility is discussed of using the drug for the treatment of conditions resulting from the presence of foreign bodies in the orbit.     

Studies of the changes in crystalline lens transparency in rabbits with experimental cataract]

Changes of the transparency of lenses were checked by means of in vivo spectrophotometry of the eye ball and by light transmission through extracted lenses in the course of experimental early cataract in rabbits caused by naphthalen. The results of investigations show that changes of lens transparency evaluated by means of in vivo spectrophotometry of the eye appear earlier than the clinically seen opacity. It speaks for the advisability of undertaking of further studies on the possibility of utilizing this method for detection of precataractous conditions in humans.     

Effect of cataract surgery incision location and intraocular lens type on ocular aberrations

PURPOSE: To determine whether Hartmann-Shack wavefront sensing detects differences in optical performance in vivo between poly(methyl methacrylate) (PMMA) and foldable acrylic intraocular lenses (IOLs) and between clear corneal and scleral tunnel incisions and whether optical differences are manifested as differences in visual performance. SETTING: Department of Optometry, University of Bradford, West Yorkshire, United Kingdom. METHODS: This study comprised 74 subjects; 17 were phakic with no ocular pathology, 20 had implantation of a Pharmacia 722C PMMA IOL through a scleral tunnel, 21 had implantation of an Alcon AcrySof IOL through a scleral tunnel, and 16 had implantation of an AcrySof IOL through a corneal incision. Visual acuity and contrast sensitivity testing, ocular optical quality measurement using Hartmann-Shack wavefront sensing, and corneal surface measurement with a videokeratoscope were performed in all cases. RESULTS: There were significant differences between groups in the total root-mean-square (RMS) wavefront aberration over a 6.0 mm pupil (F=3.91; degrees of freedom=3,70; P<.05) mediated at the 4th-order RMS, specifically spherical and tetrafoil aberrations. The PMMA-scleral group had the least aberrations and the AcrySof-corneal group the most. For a 3.5 mm diameter pupil, the total higher-order RMS wavefront aberration was not significantly different between the groups (P>.05). There were no differences between groups in corneal shape, visual acuity, or contrast sensitivity. CONCLUSIONS: Implantation of the spherical PMMA IOL led to a slight reduction in total wavefront aberration compared to phakic eyes. AcrySof IOLs induced more aberrations, especially spherical aberration. Corneal-based incisions for IOL implantation compounded this increase. Studies of the optical performance of IOLs in vivo should use wavefront sensing as the main outcome measure rather than visual measures, which are readily confounded by multiple factors.     

半乳糖性白内障晶体上皮细胞游离钙的实验研究

目的研究半乳糖性白内障晶体上皮细胞中游离钙浓度变化规律。方法给２８天鼠龄的Ｗｉｓｔａｒ大白鼠投喂５０％的半乳糖饮食复制白内障模型后,分别于给药后第１,３,７,１０,１４及１９天测量晶体上皮细胞中游离钙的浓度。结果半乳糖性白内障各时期晶体上皮细胞中游离钙的浓度均明显升高,第１０天游离钙浓度最高,是正常对照组的４～５倍。结论半乳糖性白内障晶体上皮细胞中游离钙的浓度升高,各期上升的程度不同,以皮质混浊期升高幅度最大。     

高脂血症对年龄相关性核性白内障患者晶状体密度影响分析

目的 探讨高脂血症对年龄相关性核性白内障患者晶状体密度影响.方法 收集2007年1月至2008年12月在沈阳市第四人民医院眼科就诊的年龄相关性核性白内障患者136例(189只眼)作为研究组.其中,男59例,女77例.年龄51～91岁,平均年龄(71.3±8.6)岁.同时,随机选取同期年龄匹配的90例(180只眼)健康体检者作为对照,年龄54～83岁,平均年龄(68.9±7.4)岁.受检者抽取静脉血后检测进行血清总胆固醇(TC)、甘油三酯(TG),低密度脂蛋白胆固醇(LDLC)的测定.同时对受检者进行眼科检查,检测其晶状体密度LOCSⅢ分级和LogMAR视力.结果 年龄相关性核性白内障患者的血清TC、TG和LDLC值分别为(6.958+1.87)mmo1/L、(1.97+0.71)mmol/L和(4.17+1.83)mmol/L,均显著高于对照组的(4.26+0.78)mmol/L、(1.29+0.48)mmol/L和(2.85+0.67)mmol/L,组间差异具有统计学意义,P＜0.05.年龄相关性核性白内障患者的晶状体密度、LOCSⅢ分级分值和LogMAR视力均显著高于对照组,两组差异具有统计学意义(P＜0.01).血清TC、TG和LDLC与年龄相关性核性白内障患者晶状体密度呈正相关,其相关系数r分别为0.671、0.835和0.569.经检验,P＜0.05或0.01.结论 高脂血症能使年龄相关性核性白内障患者晶状体密度增加,是年龄相关性白内障发病的危险因素之一.     

眼前段严重外伤时人工晶状体植入方法的探讨

目的 探讨提高伴严重眼前段外伤的外伤性白内障后房人工品状体（PC-IOL）植入效果的手术方法，技巧。方法 34例34眼采用分次手术的方法完成，眼前段重建，白内障摘出和PC-IOL植入术。结果 34眼均顺利植入PC-IOL。术后2-16月矫正视力0.1者11眼，0.2-0.4者13眼，0.5-0.6者7眼，0.8-1.0者3眼。术后无严重并发症。结论 采用分次手术的方法可提高伴严重眼前段外伤的外伤姓白内障PC-IOL植入的效果。     

高脂血症对年龄相关性核性白内障患者晶状体密度影响分析

Objective To investigate the lens density of age-related nuclear cataract patients affected by hyperlipidemia. Methods A total of 136 cases (189 eyes) of age-related nuclear cataract patients were collected during the treatment from January 2007 to December 2008 in the Department of Ophthalmology, the Fourth People's Hospital of Shenyang, Liaoning. There were 39 male cases and 51 female cases, with the range of ages as 51-91, and averaged 71.3±8.6 years old. At the same time, 90 (180 eyes) cases of age-matched healthy persons over the same period were randomly selected as the control, with the range of ages as 54-83,and averaged 68.9±7.4 years old. For each subject, serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDLC), were determined after venous blood samples were collected. Meanwhile, eye examinations were performed to determine the lens density of LOCS Ⅲ grading and LogMAR visual acuity.Results The serum TC, TG and LDLC values of age-related nuclear cataract patients were 6.958 ± 1.87 mmol / L, 1.97 ± 0.71 mmol/ L and 4.17±1.83 mmol / L, respectively, which were significantly higher than that of the control group (4.26±0.78 mmol/ L, 1.29±0.48 mmol/ L and 2.85 ± 0.67 mmol/ L) respectively. The difference between two groups was significant (P ＜0.05) or very significant (P ＜0.01). The lens density, LOCS Ⅲ grading score and LogMAR visual acuity were significantly higher than that of the control group.There were significantly statistical differences between data of two groups (P ＜0.01). There were significant positive correlation between Serum TC, TG, LDLC and lens density among age-related nuclear cataract patients, the correlation 0.569, respectively (P ＜0.05 or P ＜0.01). Conclusions Hyperlipemia can increase lens density of age-related nuclear cataract patients, and is a risk factor of age-related cataract.     

Progression of sugar cataract in the dog

Young beagle dogs were fed a 30% galactose diet, with or without the aldose reductase inhibitors sorbinil or M79175. Cataract formation was monitored by indirect ophthalmoscope and hand-held slit-lamp microscopy and documented by retroillumination photography. In these dogs, the first sign of cataract development was an accentuation of the anterior and posterior lens sutures (1 month after feeding), then the appearance of cortical vacuoles (3 months after feeding), and finally, the formation of predominantly equatorial cortical opacities toward the posterior cortices (4-6 months after feeding). After long-term galactose feeding, a progressive, irregular, clear zone formed at the cortical equatorial regions. Light microscopic examination of these lenses shows that the cataracts are osmotic, many of the lens fibers appear to be swollen or ruptured, and vacuoles are seen near the bow region. Moreover, these histologic changes were reduced in a dose-dependent manner in galactose-fed dogs concomitantly treated with the aldose reductase inhibitors sorbinil or M79175. The osmotic nature of these cataracts and the observation that their formation can be reduced in a dose-dependent manner by aldose reductase inhibitors are consistent with the concept that the aldose-reductase catalyzed formation of polar sugar alcohols (polyols) initiates sugar cataract formation in the dog.