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Ayalon A, Sahel JA, Chhablani J. A journey through the world of vitreous. Surv Ophthalmol 2024:S0039-6257(24)00070-5. [PMID: 38885759 DOI: 10.1016/j.survophthal.2024.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 06/06/2024] [Accepted: 06/10/2024] [Indexed: 06/20/2024]
Abstract
Vitreous, one of the largest components of the human eye, mostly contains water. Despite decades of studying the vitreous structure, numerous unanswered questions still remain, fueling ongoing active research. We attempt to provide a comprehensive overview of the current understanding of the development, morphology, biochemical composition, and function of the vitreous. We emphasize the impact of the vitreous structure and composition on the distribution of drugs. Fast developing imaging technologies, such as modern optical coherence tomography, unlocked multiple new approaches, offering the potential for in vivo study of the vitreous structure. They allowed to analyze in vivo a range of vitreous structures, such as posterior precortical vitreous pockets, Cloquet canal, channels that interconnect them, perivascular vitreous fissures, and cisterns. We provide an overview of such imaging techniques and their principles and of some challenges in visualizing vitreous structures. Finally, it explores the potential of combining the latest technologies and machine learning to enhance our understanding of vitreous structures.
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Affiliation(s)
- Anfisa Ayalon
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
| | - José-Alain Sahel
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Jay Chhablani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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2
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Wei Z, Hao C, Radeen KR, Srinivasagan R, Chen JK, Sharma S, McGee-Lawrence ME, Hamrick MW, Monnier VM, Fan X. Prevention of age-related truncation of γ-glutamylcysteine ligase catalytic subunit (GCLC) delays cataract formation. SCIENCE ADVANCES 2024; 10:eadl1088. [PMID: 38669339 PMCID: PMC11051666 DOI: 10.1126/sciadv.adl1088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 03/22/2024] [Indexed: 04/28/2024]
Abstract
A sharp drop in lenticular glutathione (GSH) plays a pivotal role in age-related cataract (ARC) formation. Despite recognizing GSH's importance in lens defense for decades, its decline with age remains puzzling. Our recent study revealed an age-related truncation affecting the essential GSH biosynthesis enzyme, the γ-glutamylcysteine ligase catalytic subunit (GCLC), at aspartate residue 499. Intriguingly, these truncated GCLC fragments compete with full-length GCLC in forming a heterocomplex with the modifier subunit (GCLM) but exhibit markedly reduced enzymatic activity. Crucially, using an aspartate-to-glutamate mutation knock-in (D499E-KI) mouse model that blocks GCLC truncation, we observed a notable delay in ARC formation compared to WT mice: Nearly 50% of D499E-KI mice remained cataract-free versus ~20% of the WT mice at their age of 20 months. Our findings concerning age-related GCLC truncation might be the key to understanding the profound reduction in lens GSH with age. By halting GCLC truncation, we can rejuvenate lens GSH levels and considerably postpone cataract onset.
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Affiliation(s)
- Zongbo Wei
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Caili Hao
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Kazi Rafsan Radeen
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Ramkumar Srinivasagan
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Jian-Kang Chen
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Shruti Sharma
- Department of Ophthalmology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Meghan E. McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Mark W. Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Vincent M. Monnier
- Department of Pathology and Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xingjun Fan
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
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Lee B, Afshari NA, Shaw PX. Oxidative stress and antioxidants in cataract development. Curr Opin Ophthalmol 2024; 35:57-63. [PMID: 37882550 DOI: 10.1097/icu.0000000000001009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
PURPOSE OF REVIEW Oxidative stress plays a central role in cataract pathogenesis, a leading cause of global blindness. This review delves into the role of oxidative stress in cataract development and key biomarkers - glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and 4-hydroxynonenal (4-HNE) - to clarify their functions and potential applications in predictive diagnostics and therapies. RECENT FINDINGS Antioxidants serve as pivotal markers in cataract pathogenesis. GSH affects the central lens due to factors such as enzyme depletion and altered connexin expression, impairing GSH diffusion. Age-related oxidative stress may hinder GSH transport via connexin channels or an internal microcirculation system. N-acetylcysteine, a GSH precursor, shows promise in mitigating lens opacity when applied topically. Additionally, SOD, particularly SOD1, correlates with increased cataract development and gel formulations have exhibited protective effects against posterior subscapular cataracts. Lastly, markers of lipid peroxidation, MDA and 4-HNE, have been shown to reflect disease severity. Studies suggest a potential link between 4-HNE and connexin channel modification, possibly contributing to reduced GSH levels. SUMMARY Oxidative stress is a significant contributor to cataract development, underscoring the importance of antioxidants in diagnosis and treatment. Notably, GSH depletion, SOD decline, and lipid peroxidation markers are pivotal factors in cataract pathogenesis, offering promising avenues for both diagnosis and therapeutic intervention.
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Affiliation(s)
- Bryanna Lee
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California, San Diego, California, USA
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Subczynski WK, Pasenkiewicz-Gierula M, Widomska J. Protecting the Eye Lens from Oxidative Stress through Oxygen Regulation. Antioxidants (Basel) 2023; 12:1783. [PMID: 37760086 PMCID: PMC10525422 DOI: 10.3390/antiox12091783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/08/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
Molecular oxygen is a primary oxidant that is involved in the formation of active oxygen species and in the oxidation of lipids and proteins. Thus, controlling oxygen partial pressure (concentration) in the human organism, tissues, and organs can be the first step in protecting them against oxidative stress. However, it is not an easy task because oxygen is necessary for ATP synthesis by mitochondria and in many biochemical reactions taking place in all cells in the human body. Moreover, the blood circulatory system delivers oxygen to all parts of the body. The eye lens seems to be the only organ that is protected from the oxidative stress through the regulation of oxygen partial pressure. The basic mechanism that developed during evolution to protect the eye lens against oxidative damage is based on the maintenance of a very low concentration of oxygen within the lens. This antioxidant mechanism is supported by the resistance of both the lipid components of the lens membrane and cytosolic proteins to oxidation. Any disturbance, continuous or acute, in the working of this mechanism increases the oxygen concentration, in effect causing cataract development. Here, we describe the biophysical basis of the mechanism and its correlation with lens transparency.
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Affiliation(s)
| | - Marta Pasenkiewicz-Gierula
- Department of Computational Biophysics and Bioinformatics, Jagiellonian University, 30-387 Krakow, Poland;
| | - Justyna Widomska
- Department of Biophysics, Medical University of Lublin, 20-090 Lublin, Poland
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Mishra D, Gade S, Glover K, Sheshala R, Singh TRR. Vitreous Humor: Composition, Characteristics and Implication on Intravitreal Drug Delivery. Curr Eye Res 2023; 48:208-218. [PMID: 36036478 DOI: 10.1080/02713683.2022.2119254] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Purpose: Intravitreal administration of drug molecules is one of the most common routes for treating posterior segment eye diseases. However, the properties of vitreous humour changes with the time. A number of ocular complications such as liquefaction of the vitreous humour, solidification of the vitreous humour in the central vitreous cavity and detachment of the limiting membrane due to the shrinking of vitreous humour are some of the factors that can drastically affect the efficacy of therapeutics delivered via intravitreal route. Although significant research has been conducted for studying the properties of vitreous humour and its changes during the ageing process, there have been limited work to understand the effect of these changes on therapeutic efficacy of intravitreal drug delivery systems. Therefore, in this review we discussed both the coomposition and characteristics of the vitreous humour, and their subsequent influence on intravitreal drug delivery.Methods: Articles were searched on Scopus, PubMed and Web of Science up to March 2022.Results: In this review, we discussed the biological composition and biomechanical properties of vitreous humour, methods to study the properties of vitreous humour and the changes in these properties and their relevance in ocular drug delivery field, with the aim to provide a useful insight into these aspects which can aid the process of development of novel intravitreal drug delivery systems.Conclusions: The composition and characteristics of the vitreous humour, and how these change during natural aging processes, directly influence intravitreal drug delivery. This review therefore highlights the importance of understanding the properties of the vitreous and identifies the need to achieve greater understanding of how changing properties of the vitreous affect the therapeutic efficacy of drugs administered for the treatment of posterior eye diseases.
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Affiliation(s)
- Deepakkumar Mishra
- School of Pharmacy, Medical Biology Centre, Queen's University Belfast, Belfast, UK
| | - Shilpkala Gade
- School of Pharmacy, Medical Biology Centre, Queen's University Belfast, Belfast, UK
| | - Katie Glover
- School of Pharmacy, Medical Biology Centre, Queen's University Belfast, Belfast, UK
| | - Ravi Sheshala
- Faculty of Pharmacy, Research Group of Affinity, Safety and Efficacy Studies (OASES), Universiti Teknologi MARA Selangor, Kuala Selangor, Malaysia
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Liu Z, Huang S, Zheng Y, Zhou T, Hu L, Xiong L, Li DWC, Liu Y. The lens epithelium as a major determinant in the development, maintenance, and regeneration of the crystalline lens. Prog Retin Eye Res 2023; 92:101112. [PMID: 36055924 DOI: 10.1016/j.preteyeres.2022.101112] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/28/2022] [Accepted: 08/02/2022] [Indexed: 02/01/2023]
Abstract
The crystalline lens is a transparent and refractive biconvex structure formed by lens epithelial cells (LECs) and lens fibers. Lens opacity, also known as cataracts, is the leading cause of blindness in the world. LECs are the principal cells of lens throughout human life, exhibiting different physiological properties and functions. During the embryonic stage, LECs proliferate and differentiate into lens fibers, which form the crystalline lens. Genetics and environment are vital factors that influence normal lens development. During maturation, LECs help maintain lens homeostasis through material transport, synthesis and metabolism as well as mitosis and proliferation. If disturbed, this will result in loss of lens transparency. After cataract surgery, the repair potential of LECs is activated and the structure and transparency of the regenerative tissue depends on postoperative microenvironment. This review summarizes recent research advances on the role of LECs in lens development, homeostasis, and regeneration, with a particular focus on the role of cholesterol synthesis (eg., lanosterol synthase) in lens development and homeostasis maintenance, and how the regenerative potential of LECs can be harnessed to develop surgical strategies and improve the outcomes of cataract surgery (Fig. 1). These new insights suggest that LECs are a major determinant of the physiological and pathological state of the lens. Further studies on their molecular biology will offer possibility to explore new approaches for cataract prevention and treatment.
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Affiliation(s)
- Zhenzhen Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Shan Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Yingfeng Zheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Tian Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Leyi Hu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Lang Xiong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - David Wan-Cheng Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China
| | - Yizhi Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, 510060, China; Research Unit of Ocular Development and Regeneration, Chinese Academy of Medical Sciences, Beijing, 100085, China.
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Parra MM, Spoth E, Ronquillo CC, Henderson R, Hartnett ME. Multimodal Retinal Imaging Findings in Two Cousins With VCAN-Related Vitreoretinopathy or Wagner Disease. Ophthalmic Surg Lasers Imaging Retina 2022; 53:639-643. [PMID: 36378611 DOI: 10.3928/23258160-20221026-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Wagner disease is a rare, nonsyndromic vitreoretinopathy caused by autosomal dominant variants in the versican (VCAN) gene. It is associated with abnormalities of the vitreoretinal interface that can lead to peripheral traction and retinal detachments, which also occur in other vitreoretinopathies such as X-linked retinoschisis (XLRS), familial exudative vitreoretinopathy (FEVR) and Stickler syndrome. There is variability in the clinical phenotype in Wagner disease potentially due to variants in VCAN gene variants. In this article, we report a family harboring the VCAN c.9265+1G>C variant and describe the clinical and retinal findings in two members. [Ophthalmic Surg Lasers Imaging Retina 2022;53:639-643.].
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Chen S, Wang M, Jian R, Li H, Liu G, Zhou C, Xiong Y, Wang W. Circ_HIPK3 Inhibits H 2O 2-Induced Lens Epithelial Cell Injury in Age-Related Cataract Depending on the Regulation of miR-495-3p/HDAC4 Pathway. Biochem Genet 2022; 61:565-577. [PMID: 36002666 DOI: 10.1007/s10528-022-10266-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 08/05/2022] [Indexed: 11/24/2022]
Abstract
Age-related cataract (ARC) is one of the most common chronic diseases. Circular RNA (circ)_HIPK3 is reported to be involved in the advancement of ARC, but its molecular mechanism has not been clarified. Our study provides a new perspective on the clinical treatment of ARC. Our data showed that the expression levels of circ_HIPK3 and histone deacetylase 4 (HDAC4) were downregulated, while microRNA (miR)-495-3p level was increased in ARC tissues and H2O2-induced SRA01/04 cells. Functional experiments showed that circ_HIPK3 and HDAC4 overexpression could inhibit H2O2-induced lens epithelial cell apoptosis and fibrosis. In terms of mechanism, we found that circ_HIPK3 could sponge miR-495-3p, miR-495-3p could target HDAC4. Besides, we confirmed that circ_HIPK3 sponged miR-495-3p to positively regulate HDAC4. Additionally, miR-495-3p overexpression or HDAC4 knockdown reversed the inhibition effect of circ_HIPK3 on H2O2-induced lens epithelial cell injury. In conclusion, our data showed that circ_HIPK3 suppressed H2O2-induced lens epithelial cell injury by regulating miR-495-3p/HDAC4 axis.
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Affiliation(s)
- Sihui Chen
- Department of Ophthalmology, Jingmen No.1 People's Hospital, No. 168, Xiangshan Avenue, Duodao District, Jingmen, 448000, China
| | - Minghong Wang
- Department of Ophthalmology, Jingmen No.1 People's Hospital, No. 168, Xiangshan Avenue, Duodao District, Jingmen, 448000, China
| | - Rui Jian
- Department of Ophthalmology, Jingmen No.1 People's Hospital, No. 168, Xiangshan Avenue, Duodao District, Jingmen, 448000, China
| | - Hui Li
- Department of Ophthalmology, Jingmen No.1 People's Hospital, No. 168, Xiangshan Avenue, Duodao District, Jingmen, 448000, China
| | - Guoli Liu
- Department of Ophthalmology, Jingmen No.1 People's Hospital, No. 168, Xiangshan Avenue, Duodao District, Jingmen, 448000, China
| | - Cuiyun Zhou
- Department of Ophthalmology, Jingmen No.1 People's Hospital, No. 168, Xiangshan Avenue, Duodao District, Jingmen, 448000, China
| | - Yan Xiong
- Department of Ophthalmology, Jingmen No.1 People's Hospital, No. 168, Xiangshan Avenue, Duodao District, Jingmen, 448000, China
| | - Wenqian Wang
- Department of Ophthalmology, Jingmen No.1 People's Hospital, No. 168, Xiangshan Avenue, Duodao District, Jingmen, 448000, China.
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The Effect of Cataract on Color Vision Measurement with the Low-Vision Cambridge Colour Test. OPHTHALMOLOGY SCIENCE 2022; 2:100153. [PMID: 36249699 PMCID: PMC9560658 DOI: 10.1016/j.xops.2022.100153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 03/22/2022] [Accepted: 03/29/2022] [Indexed: 11/29/2022]
Abstract
Purpose To quantify the effect of cataract on color vision as measured by the low-vision Cambridge Colour Test (lvCCT; Cambridge Research Systems) and to understand whether different types and severities of cataract have different effects on color vision. Design Cohort study. Participants Patients aged 18 to 95 undergoing routine cataract surgery at the Oxford Eye Hospital. Methods The lvCCT was performed to measure color sensitivity in both eyes both before and after surgery. The crystalline lens was examined and graded according to the Lens Opacities Classification System III to determine the type and severity of cataract. Measures of repeatability were performed for the data to explore test–retest bias using Bland–Altman analysis. The Wilcoxon signed-rank test was performed to assess the effect of cataract on color vision by comparing control and surgical test measurements. Three multiple linear regressions were performed to relate cataract grading or severity to color vision measurements. Main Outcome Measures Color discrimination along each of the protan, deutan, and tritan confusion lines. Results The Wilcoxon signed-rank test showed a statistically significant difference in both the protan (P = 0.024) and tritan (P = 0.020) axes on comparison of control and surgical test measurements. As severity of cataract increased, color vision sensitivity was affected more greatly, and nuclear sclerotic cataract showed the most profound effect on color vision sensitivity in the lvCCT; however, the linear regression models showed that these observations did not reach statistical significance. Conclusions Cataract surgery has a statistically significant effect on color vision in both the protan and tritan axes. The effects of specific subtypes of cataract and different severities could not be elucidated because of the high prevalence of patients with mixed cataract. The lvCCT color sensitivity measurements are used regularly as outcome measures in clinical gene therapy trials involving vitreoretinal surgery, and vitrectomy accelerates cataract formation. Therefore, it is important to quantify the effect of cataract on color vision measurements so that it may be taken into account when used as an outcome measure in clinical trials. We were unable to derive a precise correction factor for cataract on color vision measurements.
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Schindler P, Mautone L, Druchkiv V, Katz T, Spitzer MS, Skevas C. Predicting speed of progression of lens opacification after pars plana vitrectomy with silicone oil. PLoS One 2022; 17:e0268377. [PMID: 35594273 PMCID: PMC9122216 DOI: 10.1371/journal.pone.0268377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/27/2022] [Indexed: 11/18/2022] Open
Abstract
Purpose An increasing number of posterior segment disorders is routinely managed with pars plana vitrectomy (PPV). In older, phakic patients cataract formation is expected within the first two years after surgery. For younger patients its progression is individually fluctuating. This study uses an objective quantitative measurement for lens-status-monitoring after PPV with silicone oil to derive predictions for progression and severity of post-operative lens opacification evaluated in patients with rhegmatogenous retinal detachment (RRD). Methods Data acquisition was performed prospectively between March 2018 and March 2021. PentacamHR® Nucleus Staging mode (PNS) was used to objectively gather data about nuclear cataracts after PPV at different time points. Data was grouped into training and test sets for a mathematical prediction model. Via backward variable selection method a mathematical formula was set up by means of which predictions about lens densitometry (LD) can be calculated. Results 20 males [58.8%] and 14 females [41.2%] matched the inclusion criteria (mean age 50.6 years [23–75; ±12.3]). Average follow-up was 8.1 months (3,4–17.4; ±3.4). Mean baseline LD of the treated and fellow eye before surgery was 11.1% (7.7%-17.6%; ±2.0) and 11.2% (7.7%-14.8%; ±1.5), respectively. Predicted LD values by the model for five pre-selected patients closely match the observed data with an average deviation of 1.06%. Conclusions Using an objective parameter like LD delivered by the PentacamHR® PNS mode additionally to the patient’s age allows us to make an individual prediction for any time after PPV with silicone oil due to RRD for all ages. The accuracy of the model was stronger influenced by baseline LD as cofactor in the equation than patient’s age. The application for the prediction lens opacification [which can be accessed for free under the following link (https://statisticarium.com/apps/sample-apps/LensDensityOil/)] can help vitreoretinal surgeons for patient consultation on the possibility to combine PPV with cataract surgery.
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Affiliation(s)
- Philipp Schindler
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
| | - Luca Mautone
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Vasyl Druchkiv
- Department of Research & Development, Clínica Baviera, Valencia, Spain
| | - Toam Katz
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Martin Stephan Spitzer
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christos Skevas
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Altunel O, Irgat SG, Özcura F. Objective evaluation of changes in lens clarity after repeated injections of ranibizumab in patients with neovascular age-related macular degeneration. Graefes Arch Clin Exp Ophthalmol 2022; 260:2897-2904. [PMID: 35445877 DOI: 10.1007/s00417-022-05668-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/30/2022] [Accepted: 04/08/2022] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To objectively evaluate changes in lens densitometry in eyes with neovascular age-related macular degeneration (n-AMD) treated with repeated intravitreal ranibizumab injections during a 12-month period and to compare the results with those in untreated healthy fellow eyes and healthy control eyes. METHODS In this prospective study, the 36 treated eyes and the 37 untreated fellow eyes of 38 patients with n-AMD and the 32 control eyes of 32 healthy individuals were analyzed. Lens densitometry was evaluated using the Scheimpflug imaging. All data in both groups regarding lens densitometry were recorded at baseline and 12 months. RESULTS The mean densitometry of zone 1 in the treated eyes of patients had increased significantly at 12 months compared with the baseline (baseline: 9.3 ± 1.5, 12 months: 11.9 ± 1.7, p = .004) and was significantly greater than those measurements in the fellow eyes (9.8 ± 1.6 p = .02) and control eyes (9.6 ± 1.9, p = .01) at 12 months as well. There were no significant differences in terms of densitometry values between the fellow and control eyes at baseline and 12 months (for all, p > .05). CONCLUSIONS Our results objectively demonstrate early nuclear lens density changes using with Scheimpflug images in eyes with n-AMD that were treated with repeated ranibizumab injections for 12 months.
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Affiliation(s)
- Orhan Altunel
- Department of Ophthalmology, Kutahya Health Sciences University School of Medicine, Kütahya, Turkey.
| | - Saadet Gültekin Irgat
- Department of Ophthalmology, Kutahya Health Sciences University School of Medicine, Kütahya, Turkey
| | - Fatih Özcura
- Department of Ophthalmology, Kutahya Health Sciences University School of Medicine, Kütahya, Turkey
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Lim JC, Grey AC, Vaghefi E, Nye-Wood MG, Donaldson PJ. Hyperbaric oxygen as a model of lens aging in the bovine lens: The effects on lens biochemistry, physiology and optics. Exp Eye Res 2021; 212:108790. [PMID: 34648773 DOI: 10.1016/j.exer.2021.108790] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/06/2021] [Accepted: 10/09/2021] [Indexed: 12/12/2022]
Abstract
Age related nuclear (ARN) cataracts in humans take years to form and so experimental models have been developed to mimic the process in animals as a means of better understanding the etiology of nuclear cataracts in humans. A major limitation with these animal models is that many of the biochemical and physiological changes are not typical of that seen in human ARN cataract. In this review, we highlight the work of Frank Giblin and colleagues who established an in vivo animal model that replicates many of the changes observed in human ARN cataract. This model involves exposing aged guinea pigs to hyperbaric oxygen (HBO), which by causing the depletion of the antioxidant glutathione (GSH) specifically in the lens nucleus, produces oxidative changes to nuclear proteins, nuclear light scattering and a myopic shift in lens power that mimics the change that often precedes cataract development in humans. However, this model involves multiple HBO treatments per week, with sometimes up to a total of 100 treatments, spanning up to eight months, which is both costly and time consuming. To address these issues, Giblin developed an in vitro model that used rabbit lenses exposed to HBO for several hours which was subsequently shown to replicate many of the changes observed in human ARN cataract. These experiments suggest that HBO treatment of in vitro animal lenses may serve as a more economical and efficient model to study the development of cataract. Inspired by these experiments, we investigated whether exposure of young bovine lenses to HBO for 15 h could also serve as a suitable acute model of ARN cataract. We found that while this model is able to exhibit some of the biochemical and physiological changes associated with ARN cataract, the decrease in lens power we observed was more characteristic of the hyperopic shift in refraction associated with ageing. Future work will investigate whether HBO treatment to age the bovine lens in combination with an oxidative stressor such as UV light will induce refractive changes more closely associated with human ARN cataract. This will be important as developing an animal model that replicates the changes to lens biochemistry, physiology and optics observed in human ARN cataracts is urgently required to facilitate the identification and testing of anti-cataract therapies that are effective in humans.
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Affiliation(s)
- Julie C Lim
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
| | - Angus C Grey
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Ehsan Vaghefi
- School of Optometry, University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Mitchell G Nye-Wood
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Paul J Donaldson
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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13
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Schindler P, Mautone L, Bigdon E, Druchkiv V, Spitzer MS, Skevas C. Lens densitometry for assessment and prediction of cataract progression after pars plana vitrectomy with C3F8-gas for retinal detachment. PLoS One 2021; 16:e0254370. [PMID: 34252119 PMCID: PMC8274854 DOI: 10.1371/journal.pone.0254370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/24/2021] [Indexed: 11/19/2022] Open
Abstract
Purpose Lens opacification is a common complication after pars plana vitrectomy (PPV) and knowing its progression would facilitate consulting patients. The purpose of this study was to evaluate a quantitative model for lens-status-monitoring after PPV with C3F8 gas. Our model was evaluated in rhegmatogenous retinal detachment (RRD) patients of various age and lens densitometry (LD). Methods Data between March 2018 and March 2020 were evaluated retrospectively. LD measurements of the PentacamHR® Nucleus Staging mode (PNS) were used to quantify lens opacification over time. A mixed-effect regression model was designed, to enable LD predictions at any time postoperatively. Calculations were based on patient’s age and baseline LD as dependent variables. Six patients were randomly excluded during model development, to be used for testing its power afterwards. Results 34 patients (male 19 [55.9%], female 15 [44.1%]) matched the inclusion criteria. Average age was 58.5 years (32–77;±4.3) and average follow-up was 7.2 months (3,4–23.1;±1,8). Mean baseline LD of the treated and fellow eye before surgery were 10.9% (8.7%-14.8%;±0.8) and 10.7% (8.5%-14.1%;±0.6), respectively. Using our prediction model, LD values for the six pre-selected patients closely match the observed data with an average deviation of 1.07%. Conclusions Evaluation of age and baseline LD using a mixed-effect regression model might predict cataract progression in RRD patients treated with PPV and C3F8-gas. Such a tool could be considered during cataract surgery consultation in these patients.
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Affiliation(s)
- Philipp Schindler
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
| | - Luca Mautone
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Eileen Bigdon
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Vasyl Druchkiv
- Department of Research & Development, Clínica Baviera, Valencia, Spain
| | - Martin Stefan Spitzer
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christos Skevas
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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14
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Cvekl A, Eliscovich C. Crystallin gene expression: Insights from studies of transcriptional bursting. Exp Eye Res 2021; 207:108564. [PMID: 33894228 DOI: 10.1016/j.exer.2021.108564] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/05/2021] [Accepted: 03/22/2021] [Indexed: 01/26/2023]
Abstract
Cellular differentiation is marked by temporally and spatially regulated gene expression. The ocular lens is one of the most powerful mammalian model system since it is composed from only two cell subtypes, called lens epithelial and fiber cells. Lens epithelial cells differentiate into fiber cells through a series of spatially and temporally orchestrated processes, including massive production of crystallins, cellular elongation and the coordinated degradation of nuclei and other organelles. Studies of transcriptional and posttranscriptional gene regulatory mechanisms in lens provide a wide range of opportunities to understand global molecular mechanisms of gene expression as steady-state levels of crystallin mRNAs reach very high levels comparable to globin genes in erythrocytes. Importantly, dysregulation of crystallin gene expression results in lens structural abnormalities and cataracts. The mRNA life cycle is comprised of multiple stages, including transcription, splicing, nuclear export into cytoplasm, stabilization, localization, translation and ultimate decay. In recent years, development of modern mRNA detection methods with single molecule and single cell resolution enabled transformative studies to visualize the mRNA life cycle to generate novel insights into the sequential regulatory mechanisms of gene expression during embryogenesis. This review is focused on recent major advancements in studies of transcriptional bursting in differentiating lens fiber cells, analysis of nascent mRNA expression from bi-directional promoters, transient nuclear accumulation of specific mRNAs, condensation of chromatin prior lens fiber cell denucleation, and outlines future studies to probe the interactions of individual mRNAs with specific RNA-binding proteins (RBPs) in the cytoplasm and regulation of translation and mRNA decay.
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Affiliation(s)
- Ales Cvekl
- Department of Ophthalmology and VIsual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
| | - Carolina Eliscovich
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
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15
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Chiras D, Dervenis N, Dervenis P, Verma S. Phacoemulsification outcomes and complications in vitrectomised versus non-vitrectomised eyes. Clin Exp Optom 2021; 104:859-863. [PMID: 33689663 DOI: 10.1080/08164622.2021.1878865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Clinical relevance: Pars plana vitrectomy techniques have evolved in the recent years and the number of patients undergoing phacoemulsification for post-vitrectomy cataract has increased. Eye-care practitioners need to be aware of intraoperative complications and post-operative outcomes in previously vitrectomised eyes.Background: The aim of the present study is to compare the outcomes and related complications of phacoemulsification in previously vitrectomised versus non-vitrectomised eyes.Methods: This is a retrospective case-control study. Visual acuity, refractive outcomes, intra- and post-operative complications were analysed in consecutive phacoemulsification patients between January 2015 and August 2017. Patients with no post-operative data were excluded.Results: One hundred and forty-nine previously vitrectomised eyes and 608 non-vitrectomised eyes were included in the analysis. Previous pars plana vitrectomy was associated with worse logMAR visual acuity pre-operatively (0.75 ± 0.54 vs. 0.40 ± 0.33, p < 0.0001) and post-operatively (0.15 ± 0.29 vs. 0.09 ± 0.22, p = 0.014). There were no statistically significant differences between the two groups regarding refractive outcomes (p = 0.393) or posterior capsule rupture rate (p = 0.223). Previous pars plana vitrectomy was associated with a higher risk of post-operative macular oedema (p = 0.046) and posterior capsule opacification (p < 0.0001).Conclusions: Previous pars plana vitrectomy was not associated with a higher risk of intraoperative complications. However, a higher incidence of cystoid macular oedema and posterior capsule opacification were identified in the present study. Further research can provide insight into the mechanisms involved and any appropriate prevention strategies for these conditions.
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Affiliation(s)
- Dimitrios Chiras
- Cataract service, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Nikolaos Dervenis
- Cataract service, Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Panagiotis Dervenis
- Department of Biomathematics, University of Thessaly, School of Medicine, Larissa, Greece
| | - Seema Verma
- Cataract service, Moorfields Eye Hospital NHS Foundation Trust, London, UK
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16
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Srivastava O, Srivastava K, Joseph R, Wilson L. Increased Association of Deamidated αA- N101D with Lens membrane of transgenic αA N101D vs. wild type αA mice: potential effects on intracellular ionic imbalance and membrane disorganization. BMC Ophthalmol 2020; 20:484. [PMID: 33302904 PMCID: PMC7726915 DOI: 10.1186/s12886-020-01734-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/13/2020] [Indexed: 11/10/2022] Open
Abstract
We have generated two mouse models, in one by inserting the human lens αAN101D transgene in CRYαAN101D mice, and in the other by inserting human wild-type αA-transgene in CRYαAWT mice. The CRYαAN101D mice developed cortical cataract at about 7-months of age relative to CRYαAWT mice. The objective of the study was to determine the following relative changes in the lenses of CRYαAN101D- vs. CRYαAWT mice: age-related changes with specific emphasis on protein insolubilization, relative membrane-association of αAN101D vs. WTαA proteins, and changes in intracellular ionic imbalance and membrane organization. METHODS Lenses of varying ages from CRYαAWT and CRYαAN101D mice were compared for an age-related protein insolubilization. The relative lens membrane-association of the αAN101D- and WTαA proteins in the two types of mice was determined by immunohistochemical-, immunogold-labeling-, and western blot analyses. The relative levels of membrane-binding of recombinant αAN101D- and WTαA proteins was determined by an in vitro assay, and the levels of intracellular Ca2+ uptake and Na, K-ATPase mRNA were determined in the cultured epithelial cells from lenses of the two types of mice. RESULTS Compared to the lenses of CRYαAWT, the lenses of CRYαAN101D mice exhibited: (A) An increase in age-related protein insolubilization beginning at about 4-months of age. (B) A greater lens membrane-association of αAN101D- relative to WTαA protein during immunogold-labeling- and western blot analyses, including relatively a greater membrane swelling in the CRYαAN101D lenses. (C) During in vitro assay, the greater levels of binding αAN101D- relative to WTαA protein to membranes was observed. (D) The 75% lower level of Na, K-ATPase mRNA but 1.5X greater Ca2+ uptake were observed in cultured lens epithelial cells of CRYαAN101D- than those of CRYαAWT mice. CONCLUSIONS The results show that an increased lens membrane association of αAN101D--relative WTαA protein in CRYαAN101D mice than CRYαAWT mice occurs, which causes intracellular ionic imbalance, and in turn, membrane swelling that potentially leads to cortical opacity.
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Affiliation(s)
- Om Srivastava
- Department of Optometry and Vision Science, University of Alabama at Birmingham, 1716, University Boulevard, Birmingham, AL, 35294-0010, USA.
| | - Kiran Srivastava
- Department of Optometry and Vision Science, University of Alabama at Birmingham, 1716, University Boulevard, Birmingham, AL, 35294-0010, USA
| | - Roy Joseph
- Department of Optometry and Vision Science, University of Alabama at Birmingham, 1716, University Boulevard, Birmingham, AL, 35294-0010, USA
| | - Landon Wilson
- Targeted Metabolomics and Proteomics Laboratory (TMPL), Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, 35294-0010, USA
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17
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Lim JC, Caballero Arredondo M, Braakhuis AJ, Donaldson PJ. Vitamin C and the Lens: New Insights into Delaying the Onset of Cataract. Nutrients 2020; 12:E3142. [PMID: 33066702 PMCID: PMC7602486 DOI: 10.3390/nu12103142] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 12/18/2022] Open
Abstract
Cataracts or clouding of the lens is the leading cause of blindness in the world. Age and diabetes are major risk factors, and with an increasing aging and diabetic population, the burden of cataracts will grow. Cataract surgery is an effective way to restore vision; however, alternatives to cataract surgery are required to reduce the looming cataract epidemic. Since it is well established that oxidative damage plays a major role in the etiology of cataracts, antioxidants have been promoted as therapies to delay and/or prevent cataracts. However, many antioxidant interventions including vitamin C have produced mixed results as anti-cataract therapies. Progress has been made towards our understanding of lens physiology and the mechanisms involved in the delivery and uptake of antioxidants to the lens which may guide future studies aimed at addressing some of the inconsistencies seen in previous animal and human studies. Of interest is the potential for vitamin C based supplements in delaying the onset of cataracts post vitrectomy which occurs in up to 80% of patients within two years. These targeted approaches are required to reduce the burden of cataract on hospitals and improve the quality of life of our aging and diabetic population.
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Affiliation(s)
- Julie C Lim
- Department of Physiology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1142, New Zealand;
| | - Mariana Caballero Arredondo
- Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1142, New Zealand; (M.C.A.); (A.J.B.)
| | - Andrea J. Braakhuis
- Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1142, New Zealand; (M.C.A.); (A.J.B.)
| | - Paul J. Donaldson
- Department of Physiology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland 1142, New Zealand;
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18
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Wood LJ, Jolly JK, Groppe M, Benjamin L, Kirwan JF, Patel N, Elgohary MA, MacLaren RE. Binocular Visual Function in a Pre-Presbyopic Patient with Uniocular Cataract Undergoing Cataract Surgery with a Multifocal Intraocular Lens. Clin Ophthalmol 2020; 14:2001-2009. [PMID: 32764866 PMCID: PMC7371563 DOI: 10.2147/opth.s254532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/11/2020] [Indexed: 11/26/2022] Open
Abstract
Background/Aim An increasing number of pre-presbyopic patients are undergoing uniocular cataract extraction. We aim to compare the binocular status of subjects with uniocular cataracts, implanted either with a multifocal or a monofocal intraocular lens (IOL). Materials and Methods Subjects were recruited from outpatient ophthalmology clinics and randomized to an IOL type. Corrected and uncorrected LogMAR distance visual acuity (VA) and near and intermediate VA using the Radner reading test were completed. The binocular tests included the Worth Four Dot Test, fixation disparity, TNO stereoacuity and foveal suppression assessment. In addition to the near activity vision questionnaire. The trial was closed early because the chosen multifocal lens had been superseded by newer models. We report two subjects, one receiving the multifocal IOL and a monofocal IOL control with the most comparable baseline characteristics. Results Both subjects experienced uncomplicated cataract surgery, showing clinically significant improved corrected distance VA, 0.06 LogMAR and −0.16 LogMAR in the monofocal and multifocal IOL, respectively. The multifocal subject had 30 seconds of arc stereoacuity indicating normal binocular vision. Only gross binocular single vision with no stereopsis was found in the monofocal IOL subject. The latter subject also had reduced near vision quality-of-life questionnaire results. Conclusion This two-patient case series demonstrates greater binocular near ability, with the multifocal IOL, in the pre-presbyopic patient undergoing uniocular cataract surgery. The case series highlights the need, and methodology for investigating further the functional and quality-of-life benefits of implanting multifocal IOLs in pre-presbyopic patients, those in their twenties and thirties, undergoing uniocular cataract surgery.
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Affiliation(s)
- Laura J Wood
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Jasleen K Jolly
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Markus Groppe
- Stoke Mandeville Hospital, Buckingham Healthcare NHS Trust, Walton, UK
| | - Larry Benjamin
- Stoke Mandeville Hospital, Buckingham Healthcare NHS Trust, Walton, UK
| | - James F Kirwan
- Queen Alexandra Hospital, Portsmouth Hospitals NHS Trust, Portsmouth, UK
| | - Nishal Patel
- Kent and Canterbury Hospital, East Kent Hospitals University NHS Foundation Trust, Canterbury, UK
| | - Mostafa A Elgohary
- Kingston Hospital, Kingston Hospital NHS Foundation Trust, Kingston Upon Thames, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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19
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Sebag J. Vitreous and Vision Degrading Myodesopsia. Prog Retin Eye Res 2020; 79:100847. [PMID: 32151758 DOI: 10.1016/j.preteyeres.2020.100847] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 03/01/2020] [Accepted: 03/03/2020] [Indexed: 12/16/2022]
Abstract
Macromolecules comprise only 2% of vitreous, yet are responsible for its gel state, transparency, and physiologic function(s) within the eye. Myopia and aging alter collagen and hyaluronan association causing concurrent gel liquefaction and fibrous degeneration. The resulting vitreous opacities and collapse of the vitreous body during posterior vitreous detachment are the most common causes for the visual phenomenon of vitreous floaters. Previously considered innocuous, the vitreous opacities that cause floaters sometimes impact vision by profoundly degrading contrast sensitivity function and impairing quality-of-life. While many people adapt to vitreous floaters, clinically significant cases can be diagnosed with Vision Degrading Myodesopsia based upon echographic assessment of vitreous structure and by measuring contrast sensitivity function. Perhaps due to the ubiquity of floaters, the medical profession has to date largely ignored the plight of those with Vision Degrading Myodesopsia. Improved diagnostics will enable better disease staging and more accurate identification of severe cases that merit therapy. YAG laser treatments may occasionally be slightly effective, but vitrectomy is currently the definitive cure. Future developments will usher in more informative diagnostic approaches as well as safer and more effective therapeutic strategies. Improved laser treatments, new pharmacotherapies, and possibly non-invasive optical corrections are exciting new approaches to pursue. Ultimately, enhanced understanding of the underlying pathogenesis of Vision Degrading Myodesopsia should result in prevention, the ultimate goal of modern Medicine.
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Affiliation(s)
- J Sebag
- VMR Institute for Vitreous Macula Retina, Huntington Beach, CA, USA; Doheny Eye Institute, Pasadena, CA, USA; Department of Ophthalmology, Geffen School of Medicine, University of California, Los Angeles, CA, USA.
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20
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Truscott RJW, Friedrich MG. Molecular Processes Implicated in Human Age-Related Nuclear Cataract. Invest Ophthalmol Vis Sci 2020; 60:5007-5021. [PMID: 31791064 PMCID: PMC7043214 DOI: 10.1167/iovs.19-27535] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Human age-related nuclear cataract is commonly characterized by four biochemical features that involve modifications to the structural proteins that constitute the bulk of the lens: coloration, oxidation, insolubility, and covalent cross-linking. Each of these is progressive and increases as the cataract worsens. Significant progress has been made in understanding the origin of the factors that underpin the loss of lens transparency. Of these four hallmarks of cataract, it is protein-protein cross-linking that has been the most intransigent, and it is only recently, with the advent of proteomic methodology, that mechanisms are being elucidated. A diverse range of cross-linking processes involving several amino acids have been uncovered. Although other hypotheses for the etiology of cataract have been advanced, it is likely that spontaneous decomposition of the structural proteins of the lens, which do not turn over, is responsible for the age-related changes to the properties of the lens and, ultimately, for cataract. Cataract may represent the first and best characterized of a number of human age-related diseases where spontaneous protein modification leads to ongoing deterioration and, ultimately, a loss of tissue function.
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Affiliation(s)
- Roger J W Truscott
- Illawarra Health and Medical Research Institute, University of Wollongong, Australia
| | - Michael G Friedrich
- Illawarra Health and Medical Research Institute, University of Wollongong, Australia
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21
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Schwab C, Paar M, Fengler VH, Ivastinovic D, Haas A, Seidel G, Glatz W, Malle EM, Weger M, Velikay-Parel M, Faustmann G, Wedrich A, Reibnegger G, Winklhofer-Roob B, Oettl K. Gender differences in albumin and ascorbic acid in the vitreous antioxidant system. Free Radic Biol Med 2020; 146:257-263. [PMID: 31705958 DOI: 10.1016/j.freeradbiomed.2019.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 10/24/2019] [Accepted: 11/04/2019] [Indexed: 11/21/2022]
Abstract
Ascorbic acid is present at high concentrations in the vitreous and plays a central role in vitreous redox chemistry. Albumin is the main protein in the vitreous with antioxidant properties and occurs in different oxidation states, which can be used as redox indicators, but have not been studied in the vitreous. This study, therefore, addressed the vitreous redox state of cysteine-34 of albumin in relation to the ascorbic acid content, which has been suggested to exert a main function in detoxifying reactive oxygen in the vitreous. A total of 58 vitreous samples obtained from patients undergoing vitrectomy were analyzed for (i) human mercaptalbumin (HMA), the reduced thiol form; (ii) human non-mercaptalbumin1 (HNA1), a reversible oxidative modification with a disulfide at cysteine-34; and (iii) human non-mercaptalbumin2 (HNA2), a non-reversibly (highly) oxidized form of albumin; as well as (iv) ascorbic acid concentrations, to study possible relations. In addition, blood samples were taken to compare albumin redox state between plasma and the vitreous. Vitreous albumin showed greater variability in the redox state of cysteine-34 and a shift to the oxidized fractions compared to plasma albumin (P < 0.001). A strong positive relation was observed between the vitreous ascorbic acid concentrations and the reversibly oxidized form, HNA1 (P < 0.001), and a negative relation with the reduced form, HMA. Positive relations between ascorbic acid and HNA1 in the vitreous were stronger in men than in women. In contrast to HMA and HNA1, there was a distinct gender difference noted for the irreversibly oxidized form, HNA2. While males showed a positive relation between the vitreous ascorbic acid concentrations and HNA2, there was no correlation found with HNA2 in females. Our results support the view that ascorbic acid, by decreasing either directly or indirectly the concentrations of molecular oxygen, generates hydrogen peroxide, and that thiols, including HMA, are acting as antioxidants. This study for the first time provides evidence that vitreous albumin can be used as a marker molecule for the appearance of reactive oxygen species in the vitreous of patients undergoing vitrectomy. Moreover, it can be shown that there are gender differences in vitreous ascorbic acid and albumin concentrations as well as in oxidation state of vitreous albumin.
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Affiliation(s)
- Christoph Schwab
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036 Graz, Austria
| | - Margret Paar
- Physiological Chemistry, Otto-Loewi Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria.
| | - Vera Heike Fengler
- Physiological Chemistry, Otto-Loewi Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
| | - Domagoj Ivastinovic
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036 Graz, Austria
| | - Anton Haas
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036 Graz, Austria
| | - Gerald Seidel
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036 Graz, Austria
| | - Wilfried Glatz
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036 Graz, Austria
| | - Eva-Maria Malle
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036 Graz, Austria
| | - Martin Weger
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036 Graz, Austria
| | - Michaela Velikay-Parel
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036 Graz, Austria
| | - Gernot Faustmann
- Human Nutrition & Metabolism Research and Training Center, Institute of Molecular Biosciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Andreas Wedrich
- Department of Ophthalmology, Medical University of Graz, Auenbruggerplatz 4, 8036 Graz, Austria
| | - Gilbert Reibnegger
- Physiological Chemistry, Otto-Loewi Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
| | - Brigitte Winklhofer-Roob
- Human Nutrition & Metabolism Research and Training Center, Institute of Molecular Biosciences, University of Graz, Universitätsplatz 2, 8010 Graz, Austria
| | - Karl Oettl
- Physiological Chemistry, Otto-Loewi Research Center, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
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22
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Faramawi MF, Delhey LM, Chancellor JR, Sallam AB. The Influence of Diabetes Status on the Rate of Cataract Surgery Following Pars Plana Vitrectomy. Ophthalmol Retina 2019; 4:486-493. [PMID: 31786136 DOI: 10.1016/j.oret.2019.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 09/18/2019] [Accepted: 09/23/2019] [Indexed: 10/25/2022]
Abstract
PURPOSE We aimed to evaluate the association between diabetic status and the rates of cataract extraction (CE) following pars plana vitrectomy (PPV). DESIGN Retrospective cohort, multicenter database study. PARTICIPANTS Patients were selected from an insurance claims database (PharMetrics LifeLink) that included persons who had filed claims between 2006 and 2015 in the United States. METHODS We analyzed the records of 22 146 patients who underwent PPV performed by 2705 retina physicians. The vitrectomy group included patients ≥18 years of age who had undergone PPV. The control group included patients who were matched to the vitrectomy group 1:2 based on sex, diabetes mellitus (DM) status, region of the United States, and Charleston Comorbidity Index. MAIN OUTCOME MEASURES Hazard ratios (HRs) and rates of cataract surgery in patients with and without diabetes who had undergone prior PPV. RESULTS The hazard ratio for post-PPV CE was lower among patients with diabetes (3.307; 95% confidence interval [CI], 3.051-3.583) than among patients without diabetes (4.889; 95% CI, 4.670-5.119). This association was significant for all subgroups of patients with diabetes except in patients with diabetes and without retinopathy (4.086; 95% CI, 3.511-4.754). There was a significantly longer time between PPV and CE in patients with diabetes (537 days; 95% CI, 459-677 days) compared with those without diabetes (295 days; 95% CI, 278-312 days). The type of DM (type 1 vs. type 2) did not influence the rate of post-PPV cataract surgery. In persons with diabetes who underwent PPV, we observed a trend for a lower HR of cataract surgery in eyes with proliferative retinopathy (0.903; 95% CI, 0.725-1.124), and nonproliferative retinopathy (0.965; 95% CI, 0.721-1.290) compared with eyes with no retinopathy. CONCLUSIONS Eyes of patients with diabetes had a significantly decreased risk of undergoing CE after PPV surgery compared with eyes of patients without diabetes.
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Affiliation(s)
- Mohammed F Faramawi
- Epidemiology Department, College of Public Health and Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Leanna M Delhey
- Epidemiology Department, College of Public Health and Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - John R Chancellor
- Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Ahmed B Sallam
- Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
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Gong W, Li J, Wang Y, Meng J, Zheng G. miR-221 promotes lens epithelial cells apoptosis through interacting with SIRT1 and E2F3. Chem Biol Interact 2019; 306:39-46. [DOI: 10.1016/j.cbi.2019.03.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/15/2019] [Accepted: 03/25/2019] [Indexed: 11/29/2022]
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Why Is Very High Cholesterol Content Beneficial for the Eye Lens but Negative for Other Organs? Nutrients 2019; 11:nu11051083. [PMID: 31096723 PMCID: PMC6566707 DOI: 10.3390/nu11051083] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 12/13/2022] Open
Abstract
The plasma membranes of the human lens fiber cell are overloaded with cholesterol that not only saturates the phospholipid bilayer of these membranes but also leads to the formation of pure cholesterol bilayer domains. Cholesterol level increases with age, and for older persons, it exceeds the cholesterol solubility threshold, leading to the formation of cholesterol crystals. All these changes occur in the normal lens without too much compromise to lens transparency. If the cholesterol content in the cell membranes of other organs increases to extent where cholesterol crystals forma, a pathological condition begins. In arterial cells, minute cholesterol crystals activate inflammasomes, induce inflammation, and cause atherosclerosis development. In this review, we will indicate possible factors that distinguish between beneficial and negative cholesterol action, limiting cholesterol actions to those performed through cholesterol in cell membranes and by cholesterol crystals.
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Zhu X, Li D, Du Y, He W, Lu Y. DNA hypermethylation-mediated downregulation of antioxidant genes contributes to the early onset of cataracts in highly myopic eyes. Redox Biol 2018; 19:179-189. [PMID: 30172102 PMCID: PMC6122317 DOI: 10.1016/j.redox.2018.08.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/20/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022] Open
Abstract
High myopia is recognized as a risk factor for earlier onset of nuclear cataracts. One possible explanation for this is that lenses in highly myopic eyes are exposed to higher levels of oxygen than normal eyes owing to earlier vitreous liquefaction and, hence, are subjected to oxidative insults. Here, we first compared the methylation levels of six essential antioxidant genes (GSTP1, NRF2, OGG1, TXN, TXNRD1 and TXNRD2) between highly myopic cataract (HMC) and age-related cataract (ARC) lens epithelial samples via Sequenom MassARRAY. We found that specific CpG units in the promoters of GSTP1 and TXNRD2 were hypermethylated and that the expression levels of these two genes were lower in the HMC group than in the ARC group. A luciferase reporter assay confirmed the significance of differentially methylated fragments in the activation of transcription. The importance of GSTP1 and TXNRD2 in antioxidant capacity was confirmed by overexpression or knockdown experiments on cultured lens epithelial cells (LECs). In addition, the expression of DNA methyl transferase 1 (DNMT1) was higher in the lens epithelium of HMC patients than that of ARC patients, and the expression of GSTP1 and TXNRD2 was upregulated by use of a DNMT inhibitor in cultured LECs. Finally, we mimicked the intraocular environment of highly myopic eyes by treating LECs with hydrogen peroxide (H2O2) and observed both alterations in the methylation status of the GSTP1 and TXNRD2 promoters and time-dependent altered expression levels. Therefore, we propose that in an environment with high oxygen, in which lenses in highly myopic eyes are immersed, there exists a vicious cycle composed of increased oxidative stress and decreased enzymatic antioxidants via the hypermethylation of antioxidant genes. Vitreous liquefaction generates a high-O2 environment surrounding the lens. In highly myopic eyes, vitreous liquefaction occurs earlier and results in severer nuclear cataract. Methylation levels of GSTP1 and TXNRD2 were elevated in lens epithelium of highly myopic eyes. Increased oxidation and decreased enzymatic antioxidant via hypermethylation form a vicious circle in highly myopic eyes.
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Affiliation(s)
- Xiangjia Zhu
- Department of Ophthalmology, Eye and Ear, Nose, and Throat Hospital of Fudan University, 83 Fenyang Road, Shanghai 200031, China; Key Laboratory of Myopia, Ministry of Health, 83 Fenyang Road, Shanghai 200031, China; Eye Institute of Eye and Ear, Nose, and Throat Hospital of Fudan University, 83 Fenyang Road, Shanghai 200031, China; Key Laboratory of Visual Impairment and Restoration of Shanghai, Fudan University, 83 Fenyang Road, Shanghai 200031, China
| | - Dan Li
- Department of Ophthalmology, Eye and Ear, Nose, and Throat Hospital of Fudan University, 83 Fenyang Road, Shanghai 200031, China; Key Laboratory of Myopia, Ministry of Health, 83 Fenyang Road, Shanghai 200031, China; Eye Institute of Eye and Ear, Nose, and Throat Hospital of Fudan University, 83 Fenyang Road, Shanghai 200031, China; Key Laboratory of Visual Impairment and Restoration of Shanghai, Fudan University, 83 Fenyang Road, Shanghai 200031, China
| | - Yu Du
- Department of Ophthalmology, Eye and Ear, Nose, and Throat Hospital of Fudan University, 83 Fenyang Road, Shanghai 200031, China; Key Laboratory of Myopia, Ministry of Health, 83 Fenyang Road, Shanghai 200031, China; Eye Institute of Eye and Ear, Nose, and Throat Hospital of Fudan University, 83 Fenyang Road, Shanghai 200031, China; Key Laboratory of Visual Impairment and Restoration of Shanghai, Fudan University, 83 Fenyang Road, Shanghai 200031, China
| | - Wenwen He
- Department of Ophthalmology, Eye and Ear, Nose, and Throat Hospital of Fudan University, 83 Fenyang Road, Shanghai 200031, China; Key Laboratory of Myopia, Ministry of Health, 83 Fenyang Road, Shanghai 200031, China; Eye Institute of Eye and Ear, Nose, and Throat Hospital of Fudan University, 83 Fenyang Road, Shanghai 200031, China; Key Laboratory of Visual Impairment and Restoration of Shanghai, Fudan University, 83 Fenyang Road, Shanghai 200031, China
| | - Yi Lu
- Department of Ophthalmology, Eye and Ear, Nose, and Throat Hospital of Fudan University, 83 Fenyang Road, Shanghai 200031, China; Key Laboratory of Myopia, Ministry of Health, 83 Fenyang Road, Shanghai 200031, China; Eye Institute of Eye and Ear, Nose, and Throat Hospital of Fudan University, 83 Fenyang Road, Shanghai 200031, China; Key Laboratory of Visual Impairment and Restoration of Shanghai, Fudan University, 83 Fenyang Road, Shanghai 200031, China.
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Plesnar E, Szczelina R, Subczynski WK, Pasenkiewicz-Gierula M. Is the cholesterol bilayer domain a barrier to oxygen transport into the eye lens? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:434-441. [PMID: 29079282 DOI: 10.1016/j.bbamem.2017.10.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 10/20/2017] [Accepted: 10/23/2017] [Indexed: 11/16/2022]
Abstract
In the eye lens, the oxygen partial pressure is very low and the cholesterol (Chol) content in cell membranes is very high. Disturbance of these quantities results in cataract development. In human lens membranes, both bulk phospholipid-Chol domains and the pure Chol bilayer domains (CBDs) were experimentally detected. It is hypothesized that the CBD constitutes a significant barrier to oxygen transport into the lens. Transmembrane profiles of the oxygen diffusion-concentration product, obtained with electron paramagnetic resonance spin-labeling methods, allow evaluation of the oxygen permeability (PM) of phospholipid membranes but not the CBD. Molecular dynamics simulation can independently provide components of the product across any bilayer domain, thus allowing evaluation of the PM across the CBD. Therefore, to test the hypothesis, MD simulation was used. Three bilayers containing palmitoyl-oleoyl-phosphorylcholine (POPC) and Chol were built. The pure Chol bilayer modeled the CBD, the 1:1 POPC-Chol bilayer modeled the bulk membrane in which the CBD is embedded, and the POPC bilayer was a reference. To each model, 200 oxygen molecules were added. After equilibration, the oxygen concentration and diffusion profiles were calculated for each model and multiplied by each other. From the respective product profiles, the PM of each bilayer was calculated. Favorable comparison with experimental data available only for the POPC and POPC-Chol bilayers validated these bilayer models and allowed the conclusion that oxygen permeation across the CBD is ~10 smaller than across the bulk membrane, supporting the hypothesis that the CBD is a barrier to oxygen transport into the eye lens.
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Affiliation(s)
- Elzbieta Plesnar
- Department of Computational Biophysics and Bioinformatics, WBBiB, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland.
| | - Robert Szczelina
- Department of Bioinformatics, MCB, Jagiellonian University, Gronostajowa 7A, 30-387 Krakow, Poland.
| | - Witold K Subczynski
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
| | - Marta Pasenkiewicz-Gierula
- Department of Computational Biophysics and Bioinformatics, WBBiB, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland.
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Does having children earlier help you see things more clearly? Menopause 2017; 24:994-995. [DOI: 10.1097/gme.0000000000000946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Cholesterol Bilayer Domains in the Eye Lens Health: A Review. Cell Biochem Biophys 2017; 75:387-398. [PMID: 28660427 PMCID: PMC5691107 DOI: 10.1007/s12013-017-0812-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 06/15/2017] [Indexed: 11/06/2022]
Abstract
The most unique biochemical characteristic of the eye lens fiber cell plasma membrane is its extremely high cholesterol content, the need for which is still unclear. It is evident, however, that the disturbance of Chol homeostasis may result in damages associated with cataracts. Electron paramagnetic resonance methods allow discrimination of two types of lipid domains in model membranes overloaded with Chol, namely, phospholipid-cholesterol domains and pure Chol bilayer domains. These domains are also detected in human lens lipid membranes prepared from the total lipids extracted from lens cortices and nuclei of donors from different age groups. Independent of the age-related changes in phospholipid composition, the physical properties of phospholipid-Chol domains remain the same for all age groups and are practically identical for cortical and nuclear membranes. The presence of Chol bilayer domains in these membranes provides a buffering capacity for cholesterol concentration in the surrounding phospholipid-Chol domains, keeping it at a constant saturating level and thus keeping the physical properties of the membrane consistent with and independent of changes in phospholipid composition. It seems that the presence of Chol bilayer domains plays an integral role in the regulation of cholesterol-dependent processes in fiber cell plasm membranes and in the maintenance of fiber cell membrane homeostasis.
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Goralska M, Fleisher LN, McGahan MC. Vitreous Humor Changes Expression of Iron-Handling Proteins in Lens Epithelial Cells. Invest Ophthalmol Vis Sci 2017; 58:1187-1195. [PMID: 28245299 PMCID: PMC5338632 DOI: 10.1167/iovs.16-20610] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose In humans, vitrectomy is associated with development of nuclear cataracts. Iron catalyzes free radical formation causing oxidative damage, which is implicated in cataract formation. This study was designed to determine if vitreous humor, which can initiate differentiation of lens epithelial cells, would have an effect on iron-handling proteins. Methods Cultured canine lens epithelial cells were treated with collected canine vitreous humor. Lysates of treated and control cells were separated by SDS-PAGE. Ferritin H- and L-chains, transferrin receptor 1, and aquaporin 0 were immunodetected and quantitated with specific antibodies. Morphologic changes in treated cells were assessed. Results Treatment of lens epithelial cells with a 33% (vol/vol) solution of vitreous humor changed the morphology of lens cells and induced expression of aquaporin 0, a marker of fiber cell differentiation that was undetectable in control cells. Treatment did not modify the size of iron-handling proteins but significantly increased content of ferritin from 2.9- to 8.8-fold over control and decreased levels of transferrin receptor by 37% to 59%. Conclusions Vitreous humor may significantly limit iron uptake by transferrin/transferrin receptor pathway, and by increasing ferritin levels could profoundly increase the iron-storage capacity of ferritin in lens cells. Vitreous humor may play a significant protective role against iron-catalyzed oxidative damage of lens epithelial cells and therefore in the formation of cataracts.
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Affiliation(s)
- Malgorzata Goralska
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, North Carolina, United States
| | - Lloyd N Fleisher
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, North Carolina, United States
| | - M Christine McGahan
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, North Carolina, United States
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Ma N, Siegfried C, Kubota M, Huang J, Liu Y, Liu M, Dana B, Huang A, Beebe D, Yan H, Shui YB. Expression Profiling of Ascorbic Acid-Related Transporters in Human and Mouse Eyes. Invest Ophthalmol Vis Sci 2017; 57:3440-50. [PMID: 27367512 PMCID: PMC4961060 DOI: 10.1167/iovs.16-19162] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Purpose Ascorbic acid (AsA) is an important antioxidant in the eye. Ascorbic acid is usually transported by sodium-dependent AsA transporters (SVCTs), and dehydroascorbic acid (DHA) by glucose transporters (GLUTs). This study investigates these AsA-related transporters in human compared with mouse eyes. Methods Five pairs of human donor eyes and 15 pairs of mouse eyes were collected. Immunofluorescence and in situ hybridization were performed to detect SVCTs and GLUTs expression in the ciliary epithelium, retina, and lens epithelial cells (LECs). These tissues were isolated with laser microdissection followed by extraction of total RNA. Quantitative PCR (qPCR) was performed to examine the mRNA level of SVCTs and GLUTs in human and mouse ocular tissues. Results Immunofluorescence and in situ hybridization showed SVCT2 and GLUT1 expression in human ciliary epithelium with varied distributions. Sodium-dependent AsA transporter 2 is expressed only in the pigmented epithelium (PE), and GLUT1 is predominately expressed in the nonpigmented epithelium (NPE). However, SVCT2 was not identified in mouse ciliary epithelium, whereas GLUT1 expressed in both PE and NPE. Laser microdissection and qPCR revealed high levels of SVCT2 mRNA in human RPE cells and murine neural retina. Sodium-dependent AsA transporter 1 mRNA could be detected only in human and murine LECs. Glucose transporter 3 and GLUT4 mRNA could not be detected in either the human or mouse ciliary processes or in the lens epithelium. Conclusions These fundamental findings indicate AsA transporter expression in eyes of humans is significantly different compared with mice. This may explain why human aqueous and vitreous humors contain higher AsA levels compared with other animals.
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Affiliation(s)
- Nan Ma
- Department of Ophthalmology and Visual Sciences Washington University School of Medicine, St. Louis, Missouri, United States 2Department of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Carla Siegfried
- Department of Ophthalmology and Visual Sciences Washington University School of Medicine, St. Louis, Missouri, United States
| | - Miyuki Kubota
- Department of Ophthalmology and Visual Sciences Washington University School of Medicine, St. Louis, Missouri, United States 3Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Jie Huang
- Department of Ophthalmology and Visual Sciences Washington University School of Medicine, St. Louis, Missouri, United States
| | - Ying Liu
- Department of Ophthalmology and Visual Sciences Washington University School of Medicine, St. Louis, Missouri, United States
| | - Margaret Liu
- Department of Ophthalmology and Visual Sciences Washington University School of Medicine, St. Louis, Missouri, United States
| | - Belinda Dana
- Department of Ophthalmology and Visual Sciences Washington University School of Medicine, St. Louis, Missouri, United States
| | - Andrew Huang
- Department of Ophthalmology and Visual Sciences Washington University School of Medicine, St. Louis, Missouri, United States
| | - David Beebe
- Department of Ophthalmology and Visual Sciences Washington University School of Medicine, St. Louis, Missouri, United States
| | - Hong Yan
- Department of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Ying-Bo Shui
- Department of Ophthalmology and Visual Sciences Washington University School of Medicine, St. Louis, Missouri, United States
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Yee KM, Tan S, Lesnik Oberstein SY, Filas B, Nguyen JH, Nguyen-Cuu J, Sebag J. Incidence of Cataract Surgery after Vitrectomy for Vitreous Opacities. ACTA ACUST UNITED AC 2017; 1:154-157. [DOI: 10.1016/j.oret.2016.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 11/25/2016] [Accepted: 11/28/2016] [Indexed: 10/20/2022]
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Yan H, Wang D, Ding TB, Zhou HY, Yan WJ, Wang XC. Comparison of lens oxidative damage induced by vitrectomy and/or hyperoxia in rabbits. Int J Ophthalmol 2017; 10:6-14. [PMID: 28149770 DOI: 10.18240/ijo.2017.01.02] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 10/13/2016] [Indexed: 11/23/2022] Open
Abstract
AIM To compare of lens oxidative damage induced by vitrectomy and/or hyperoxia in rabbit. METHODS Sixteen New Zealand rabbits (2.4-2.5 kg) were randomly divided into two groups (Group A, n=12; Group B, n=4). In Group A, the right eyes were treated with vitrectomy and systemic hyperoxia (oxygen concentration: 80%-85%, 1 ATA, 4h/d) (Group A-right), and the left eyes were treated with hyperoxia without vitrectomy surgery (Group A-left). Four rabbits in group B (eight eyes) were untreated as the controls. Lens transparency was monitored with a slit lamp and recorded before and after vitrectomy. After hyperoxic treatment for 6mo, the eyeballs were removed and the lens cortices (containing the capsules) and nuclei were separated for further morphological and biochemical evaluation. RESULTS Six months after treatments, there were no significant morphological changes in the lenses in any experimental group when observed with a slit lamp. However, the levels of water-soluble proteins and ascorbate, and the activities of catalase and Na+-K+-ATPase were significantly reduced, whereas the levels of malondialdehyde and transforming growth factor β2 (TGF-β2) were significantly elevated, in both the cortices and nuclei of eyes treated with vitrectomy and hyperoxia. The increase in protein-glutathione mixed disulfides and the reduction in water-soluble proteins were more obvious in the lens nuclei. The levels of ascorbate in the vitreous fluid were also reduced after vitrectomy, whereas TGF-β2 increased after vitrectomy and hyperoxia. Systemic hyperoxia exposure increased these effects. CONCLUSION Removal of the intact vitreous gel with vitrectomy and exposing the lens to increased oxygen from the retina induce lens oxidation and aggregation. Thus, an intact vitreous gel structure may protect the lens from oxidative insult and maintain lens transparency.
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Affiliation(s)
- Hong Yan
- Department of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi'an 710038, Shaanxi Province, China; Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, the First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Dan Wang
- Department of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi'an 710038, Shaanxi Province, China
| | - Tian-Bing Ding
- Department of Microbiology, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, China
| | - Hai-Yan Zhou
- Department of Ophthalmology, Shaanxi Provincial People's Hospital, Xi'an 710068, Shaanxi Province, China
| | - Wei-Jia Yan
- Department of Clinical Medicine, Xi'an Medical University, Xi'an 710021, Shaanxi Province, China
| | - Xin-Chuan Wang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an 710038, Shaanxi Province, China
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Abstract
BACKGROUND The physiological aging of the eye is associated with loss of visual function. Age-related changes of the eye can result in ophthalmological diseases. The aim of this article is to display morphological, histological and molecular biological alterations of the aging eye. MATERIAL AND METHODS A web-based search and review of the literature for aging of the visual system including cornea, lens, vitreous humor, retina, retinal pigment epithelium (RPE), choroidea and optic nerve were carried out. The most important results related to morphological, histological and molecular biological changes are summarized. RESULTS Age-related, morphological alterations can be found in preretinal structures, e. g. cornea, lens and vitreous humor, as well as neuronal structures, such as the retina. In addition to negligible clinical signs of the aging eye, there are clinically relevant changes which can develop into pathological ophthalmological diseases. These transitions from age-related alterations to relevant ophthalmological diseases, e. g. age-related macular degeneration and glaucoma are continuous. CONCLUSION An understanding of aging could provide predictive factors to detect the conversion of physiological aging into pathological conditions. The derivation of physiological markers or new approaches to detection and treatment of disease-related entities associated with the risk factor aging are desirable. Translational approaches in clinical and basic science are necessary to provide new therapeutic options for relevant ophthalmological diseases in the future.
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Kataria AS, Thompson JT. Cataract Formation and Progression in Patients Less Than 50 Years of Age after Vitrectomy. Ophthalmol Retina 2016; 1:149-153. [PMID: 31047271 DOI: 10.1016/j.oret.2016.09.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/12/2016] [Indexed: 11/16/2022]
Abstract
PURPOSE To measure the rate of cataract development and progression of nuclear sclerotic cataracts (NSC), posterior subcapsular cataracts (PSC), and cortical spoking cataracts in nondiabetic patients <50 years of age after a pars plana vitrectomy. DESIGN Retrospective cohort study. SUBJECTS Twenty-six eyes of 26 patients <50 years of age that had undergone a pars plana vitrectomy were included. METHODS Clinical records were reviewed retrospectively. MAIN OUTCOME MEASURES The NSC, PSC, and cortical spoking scores were recorded preoperatively and 1, 3, 6, 9, and 12 months after surgery until discharged from care, lost to follow-up, or last visit before cataract surgery. Eyes were graded on a scale of 0 to 4.0 using the lens opacities classification system LOCS II before and after pars plana vitrectomy for macular hole, epiretinal membranes, and vitreous hemorrhage. Linear regression analysis was performed to evaluate the rate of change in cataract score with elapsed time since surgery. RESULTS The mean age at surgery was 30.6±14.3 years in 26 eyes with a median follow-up of 12 months. Eleven of 26 surgical eyes (42.3%) that had a baseline NSC and PSC score of zero in their surgical eye developed NSC, PSC, or both after vitrectomy. The mean progression for NSC, PSC, and cortical spoking were 0.327±0.14 (P = 0.032), 0.414±0.14 (P = 0.008), and 0.00±0.00 over a mean follow-up of 1.43 years, respectively. Linear regression analysis shows minimal increase in NSC (+0.09/year; P < 0.001; R2 = +0.331), a slight increase in PSC (+0.16/year; P < 0.001; R2 = +0.835), and a minimal decrease in cortical spoking (-0.02/year; P < 0.05; R2 = -0.09). CONCLUSIONS Our findings suggest there is a minimal but significant increase in NSC and PSC scores for patients <50 years after pars plana vitrectomy. Cataract progression is not a significant factor in the first few years after vitrectomy in patients <50 years of age.
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Affiliation(s)
- Aman S Kataria
- Johns Hopkins University School of Public Health, Baltimore, Maryland
| | - John T Thompson
- Retina Specialists, Greater Baltimore Medical Center, Towson, Maryland.
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Ainsbury EA, Barnard S, Bright S, Dalke C, Jarrin M, Kunze S, Tanner R, Dynlacht JR, Quinlan RA, Graw J, Kadhim M, Hamada N. Ionizing radiation induced cataracts: Recent biological and mechanistic developments and perspectives for future research. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 770:238-261. [DOI: 10.1016/j.mrrev.2016.07.010] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/27/2016] [Accepted: 07/28/2016] [Indexed: 02/06/2023]
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Zhou H, Yan H, Yan W, Wang X, Ma Y, Wang J. Quantitative proteomics analysis with iTRAQ in human lenses with nuclear cataracts of different axial lengths. Mol Vis 2016; 22:933-43. [PMID: 27559289 PMCID: PMC4972033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 07/29/2016] [Indexed: 11/02/2022] Open
Abstract
PURPOSE The goal of this study was to identify and quantify the differentially expressed proteins in human nuclear cataract with different axial lengths. METHODS Thirty-six samples of human lens nuclei with hardness grade III or IV were obtained during cataract surgery with extracapsular cataract extraction (ECCE). Six healthy transparent human lens nuclei were obtained from fresh healthy cadaver eyes during corneal transplantation surgery. The lens nuclei were divided into seven groups (six lenses in each group) according to the optic axis: Group A (mean axial length 28.7±1.5 mm; average age 59.8±1.9 years), Group B (mean axial length 23.0±0.4 mm; average age 60.3±2.5 years), Group C (mean axial length 19.9±0.5 mm; average age 55.1±2.5 years), Group D (mean axial length 28.7±1.4 mm; average age 58.0±4.0 years), Group E (mean axial length 23.0±0.3 mm; average age 56.9±4.2 years), and Group F (mean axial length 20.7±0.6 mm; average age 57.6±5.3 years). The six healthy transparent human lenses were included in a younger group with standard optic axes, Group G (mean axial length 23.0±0.5 mm; average age 34.7±4.2 years).Water-soluble, water-insoluble, and water-insoluble-urea-soluble protein fractions were extracted from the samples. The three-part protein fractions from the individual lenses were combined to form the total proteins of each sample. The proteomic profiles of each group were analyzed using 8-plex isobaric tagging for relative and absolute protein quantification (iTRAQ) labeling combined with two-dimensional liquid chromatography tandem mass spectrometry (2D-LC-MS/MS). The data were analyzed with ProteinPilot software for peptide matching, protein identification, and quantification. Differentially expressed proteins were validated with western blotting. RESULTS We employed biological and technical replicates and selected the intersection of the two sets of results, which included 40 proteins. From the 40 proteins identified, six were selected as differentially expressed proteins closely related to axial length. The six proteins were gap junction alpha-3 protein, beta-crystallin B2, T-complex protein 1 subunit beta, gamma-enolase, pyruvate kinase isozymes M1/M2, and sorbitol dehydrogenase. Levels of beta-crystallin B2 expression were decreased in nuclear cataracts with longer axial length. The results of the mass spectrometric analysis were consistent with the western blot validation. CONCLUSION The discovery of these differentially expressed proteins provides valuable clues for understanding the pathogenesis of axial-related nuclear cataract. The results indicate that beta-crystallin B2 (CRBB2) may be involved in axial-related nuclear cataract pathogenesis. Further studies are needed to investigate the correlation between CRBB2 and axial-related nuclear cataract.
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Affiliation(s)
- Haiyan Zhou
- Department of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi’an, China,,Department of Ophthalmology, Shaanxi Provincial People’s Hospital, Xi’an, China
| | - Hong Yan
- Department of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi’an, China,,Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, the First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Weijia Yan
- Department of Clinical Medicine, Xi’an Medical University, Xi’an, China
| | - Xinchuan Wang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
| | - Yong Ma
- Department of Ophthalmology, Shaanxi Provincial People’s Hospital, Xi’an, China
| | - Jianping Wang
- Department of Ophthalmology, Shaanxi Provincial People’s Hospital, Xi’an, China
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Fan X, Monnier VM, Whitson J. Lens glutathione homeostasis: Discrepancies and gaps in knowledge standing in the way of novel therapeutic approaches. Exp Eye Res 2016; 156:103-111. [PMID: 27373973 DOI: 10.1016/j.exer.2016.06.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 03/10/2016] [Accepted: 06/25/2016] [Indexed: 01/18/2023]
Abstract
Cataract is the major cause of blindness worldwide. The WHO has estimated around 20 million people have bilateral blindness from cataract, and that number is expected to reach 50 million in 2050. The cataract surgery is currently the main treatment approach, though often associated with complications, such as Posterior Capsule Opacification (PCO)-also known as secondary cataract. The lens is an avascular ocular structure equipped with an unusually high level of glutathione (GSH), which plays a vital role in maintaining lens transparency by regulating lenticular redox state. The lens epithelium and outer cortex are thought to be responsible for providing the majority of lens GSH via GSH de novo synthesis, assisted by a continuous supply of constituent amino acids from the aqueous humor, as well as extracellular GSH recycling from the gamma-glutamyl cycle. However, when de novo synthesis is impaired, in the presence of low GSH levels, as in the aging human lens, compensatory mechanisms exist, suggesting that the lens is able to uptake GSH from the surrounding ocular tissues. However, these uptake mechanisms, and the GSH source and its origin, are largely unknown. The lens nucleus does not have the ability to synthesize its own GSH and fully relies on transport from the outer cortex by yet unknown mechanisms. Understanding how aging reduces GSH levels, particularly in the lens nucleus, how it is associated with age-related nuclear cataract (ARNC), and how the lens compensates for GSH loss via external uptake should be a major research priority. The intent of this review, which is dedicated to the memory of David C. Beebe, is to summarize our current understanding of lens GSH homeostasis and highlight discrepancies and gaps in knowledge that stand in the way of pharmacologically minimizing the impact of declining GSH content in the prevention of age-related cataract.
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Affiliation(s)
- Xingjun Fan
- Department of Pathology, Case Western Reserve University, USA.
| | - Vincent M Monnier
- Department of Pathology, Case Western Reserve University, USA; Department of Biochemistry, Case Western Reserve University, USA
| | - Jeremy Whitson
- Department of Pathology, Case Western Reserve University, USA
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Shah NS, Beebe DC, Lake SP, Filas BA. On the Spatiotemporal Material Anisotropy of the Vitreous Body in Tension and Compression. Ann Biomed Eng 2016; 44:3084-3095. [DOI: 10.1007/s10439-016-1589-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/04/2016] [Indexed: 11/29/2022]
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Subczynski WK, Mainali L, Raguz M, O'Brien WJ. Organization of lipids in fiber-cell plasma membranes of the eye lens. Exp Eye Res 2016; 156:79-86. [PMID: 26988627 DOI: 10.1016/j.exer.2016.03.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 02/02/2016] [Accepted: 03/07/2016] [Indexed: 11/15/2022]
Abstract
The plasma membrane together with the cytoskeleton forms the only supramolecular structure of the matured fiber cell which accounts for mostly all fiber cell lipids. The purpose of this review is to inform researchers about the importance of the lipid bilayer portion of the lens fiber cell plasma membranes in the maintaining lens homeostasis, and thus protecting against cataract development.
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Affiliation(s)
- Witold K Subczynski
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| | - Laxman Mainali
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Marija Raguz
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Medical Physics and Biophysics, School of Medicine, University of Split, Split, Croatia
| | - William J O'Brien
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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Jarrin M, Young L, Wu W, Girkin JM, Quinlan RA. In vivo, Ex Vivo, and In Vitro Approaches to Study Intermediate Filaments in the Eye Lens. Methods Enzymol 2016; 568:581-611. [DOI: 10.1016/bs.mie.2015.09.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Hejtmancik JF, Riazuddin SA, McGreal R, Liu W, Cvekl A, Shiels A. Lens Biology and Biochemistry. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:169-201. [PMID: 26310155 DOI: 10.1016/bs.pmbts.2015.04.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The primary function of the lens resides in its transparency and ability to focus light on the retina. These require both that the lens cells contain high concentrations of densely packed lens crystallins to maintain a refractive index constant over distances approximating the wavelength of the light to be transmitted, and a specific arrangement of anterior epithelial cells and arcuate fiber cells lacking organelles in the nucleus to avoid blocking transmission of light. Because cells in the lens nucleus have shed their organelles, lens crystallins have to last for the lifetime of the organism, and are specifically adapted to this function. The lens crystallins comprise two major families: the βγ-crystallins are among the most stable proteins known and the α-crystallins, which have a chaperone-like function. Other proteins and metabolic activities of the lens are primarily organized to protect the crystallins from damage over time and to maintain homeostasis of the lens cells. Membrane protein channels maintain osmotic and ionic balance across the lens, while the lens cytoskeleton provides for the specific shape of the lens cells, especially the fiber cells of the nucleus. Perhaps most importantly, a large part of the metabolic activity in the lens is directed toward maintaining a reduced state, which shelters the lens crystallins and other cellular components from damage from UV light and oxidative stress. Finally, the energy requirements of the lens are met largely by glycolysis and the pentose phosphate pathway, perhaps in response to the avascular nature of the lens. Together, all these systems cooperate to maintain lens transparency over time.
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Affiliation(s)
- J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - S Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Rebecca McGreal
- Department of Genetics and Ophthalmology, Albert Einstein College of Medicine, Bronx, New York, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Wei Liu
- Department of Genetics and Ophthalmology, Albert Einstein College of Medicine, Bronx, New York, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Ales Cvekl
- Department of Genetics and Ophthalmology, Albert Einstein College of Medicine, Bronx, New York, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Alan Shiels
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, USA.
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Zhou HY, Yan H, Wang LL, Yan WJ, Shui YB, Beebe DC. Quantitative proteomics analysis by iTRAQ in human nuclear cataracts of different ages and normal lens nuclei. Proteomics Clin Appl 2015; 9:776-86. [PMID: 25418515 DOI: 10.1002/prca.201400061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 10/02/2014] [Accepted: 11/18/2014] [Indexed: 01/01/2023]
Abstract
PURPOSE The goal of this study was to quantitatively identify the differentially expressed proteins in nuclear cataracts of different ages and normal lens nuclei in humans. EXPERIMENTAL DESIGN Forty-eight human lens nucleus samples with hardness grades III, IV were obtained during cataract surgery by extracapsular cataract extraction. Seven normal transparent human lens nuclei were obtained from fresh normal cadaver eyes during corneal transplantation surgery. Lens nuclei were divided into seven groups according to age and optic axis: Group A (average age 80.8 ± 1.2 years), Group B (average age 57.0 ± 4.0 years), Group C average age 80.3 ± 4.5 years), Group D (average age 56.9 ± 4.2 years), Group E (average age 78.1 ± 2.5 years), Group F (average age 57.6 ± 3.3 years) and Group G (seven normal transparent human lenses from normal cadaver eyes, average age 34.7 ± 4.2 years). Water-soluble, water-insoluble, and water-insoluble-urea-soluble protein fractions were extracted from samples. The three-part protein fractions from the individual lenses were combined to form the total proteins of each sample. The proteomic profiles of each group were further analyzed using 8-plex iTRAQ labeling combined with 2D-LC-MS/MS. The data were analyzed with the ProteinPilot software for peptide matching, protein identification, and quantification. Differentially expressed proteins were validated by Western blotting. RESULTS We employed biological and technical replicates and selected the intersection of the two results, which included 80 proteins. Nine proteins were differentially expressed among the 80 proteins identified using proteomic techniques. In age-related nuclear cataracts (ARNC), the expression levels of fatty acid-binding protein and pterin-4-alpha-carbinolamine dehydratase were upregulated, whereas the levels of alpha-crystallin B chain (CRYAB), GSH synthetase, phakinin, gamma-crystallin C, phosphoglycerate kinase 1, betaine-homocysteine S-methyltransferase 1 (BHMT1), and spectrin beta chain were downregulated. These proteins may be associated with abnormal protein aggregation and oxidative stress. GSH synthetase and CRYAB expression levels in the nuclear cataract decreased with age. The mass spectrometric analysis results were consistent with the Western blot validation. CONCLUSION AND CLINICAL RELEVANCE The results indicate that CRYAB and GSH synthetase may be involved in ARNC pathogenesis. iTRAQ combined with 2D-LC-MS/MS provides new methods for future studies of pathological mechanisms and protective drug development for ARNC.
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Affiliation(s)
- Hai Yan Zhou
- Department of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.,Department of Ophthalmology, Xi'an Central Hospital, Xi'an, China
| | - Hong Yan
- Department of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Li Li Wang
- Department of Ophthalmology, Xi'an Central Hospital, Xi'an, China
| | - Wei Jia Yan
- Department of Clinical Medicine, Xi'an Medical University, Xi'an, China
| | - Ying Bo Shui
- Department of Ophthalmology and Visual Sciences, Washington University, Saint Louis, MO, USA
| | - David C Beebe
- Department of Ophthalmology and Visual Sciences, Washington University, Saint Louis, MO, USA
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Raguz M, Mainali L, O'Brien WJ, Subczynski WK. Lipid domains in intact fiber-cell plasma membranes isolated from cortical and nuclear regions of human eye lenses of donors from different age groups. Exp Eye Res 2015; 132:78-90. [PMID: 25617680 DOI: 10.1016/j.exer.2015.01.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 01/05/2015] [Accepted: 01/20/2015] [Indexed: 02/02/2023]
Abstract
The results reported here clearly document changes in the properties and the organization of fiber-cell membrane lipids that occur with age, based on electron paramagnetic resonance (EPR) analysis of lens membranes of clear lenses from donors of age groups from 0 to 20, 21 to 40, and 61 to 80 years. The physical properties, including profiles of the alkyl chain order, fluidity, hydrophobicity, and oxygen transport parameter, were investigated using EPR spin-labeling methods, which also provide an opportunity to discriminate coexisting lipid domains and to evaluate the relative amounts of lipids in these domains. Fiber-cell membranes were found to contain three distinct lipid environments: bulk lipid domain, which appears minimally affected by membrane proteins, and two domains that appear due to the presence of membrane proteins, namely boundary and trapped lipid domains. In nuclear membranes the amount of boundary and trapped phospholipids as well as the amount of cholesterol in trapped lipid domains increased with the donors' age and was greater than that in cortical membranes. The difference between the amounts of lipids in domains uniquely formed due to the presence of membrane proteins in nuclear and cortical membranes increased with the donors' age. It was also shown that cholesterol was to a large degree excluded from trapped lipid domains in cortical membranes. It is evident that the rigidity of nuclear membranes was greater than that of cortical membranes for all age groups. The amount of lipids in domains of low oxygen permeability, mainly in trapped lipid domains, were greater in nuclear than cortical membranes and increased with the age of donors. These results indicate that the nuclear fiber cell plasma membranes were less permeable to oxygen than cortical membranes and become less permeable to oxygen with age. In clear lenses, age-related changes in the lens lipid and protein composition and organization appear to occur in ways that increase fiber cell plasma membrane resistance to oxygen permeation.
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Affiliation(s)
- Marija Raguz
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Medical Physics and Biophysics, School of Medicine, University of Split, Split, Croatia
| | - Laxman Mainali
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - William J O'Brien
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Witold K Subczynski
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Abstract
AbstractObjectiveWe conducted a meta-analysis to evaluate the relationship between vitamin E and age-related cataract (ARC).DesignThe fixed- or random-effect model was selected based on heterogeneity. Meta-regression was used to explore potential sources of between-study heterogeneity. Publication bias was evaluated using Begg’s test. The dose–response relationship was assessed by a restricted cubic spline model.SettingRelevant studies were identified by a search of PubMed and the Cochrane Library to May 2014, without language restrictions.SubjectsStudies involved samples of people of all ages.ResultsDietary vitamin E intake, dietary and supplemental vitamin E intake, and high serum tocopherol levels were significantly associated with decreased risk of ARC, the pooled relative risk was 0·73 (95 % CI 0·58, 0·92), 0·86 (95 % CI 0·75, 0·99) and 0·77 (95 % CI 0·66, 0·91), respectively. Supplemental vitamin E intake was non-significantly associated with ARC risk (relative risk=0·92; 95 % CI 0·78, 1·07). The findings from dose–response analysis showed evidence of a non-linear association between dietary vitamin E intake and ARC. The risk of ARC decreased with dietary vitamin E intake from 7 mg/d (relative risk=0·94; 95 % CI 0·90, 0·97).ConclusionsThe findings of the meta-analysis indicated that dietary vitamin E intake, dietary and supplemental vitamin E intake, and high level of serum tocopherol might be significantly associated with reduced ARC risk.
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Abstract
PURPOSE Floaters impact vision but the mechanism is unknown. We hypothesize that floaters reduce contrast sensitivity function, which can be normalized by vitrectomy, and that minimally invasive vitrectomy will have lower incidences of retinal tears (reported at 30%) and cataracts (50-76%). METHODS Seventy-six eyes (34 phakic) with floaters were evaluated in 2 separate studies. Floater etiologies were primarily posterior vitreous detachment in 61 of 76 eyes (80%) and myopic vitreopathy in 24 of 76 eyes (32%). Minimally invasive 25G vitrectomy was performed without posterior vitreous detachment induction, leaving anterior vitreous, and using nonhollow probes for cannula extraction. Efficacy was studied prospectively (up to 9 months) in 16 floater cases with Freiburg Acuity Contrast Testing (Weber index [%W] reproducibility = 92.1%) and the National Eye Institute Visual Function Questionnaire. Safety was separately evaluated in 60 other cases followed up on an average of 17.5 months (range, 3-51 months). RESULTS Floater eyes had 67% contrast sensitivity function attenuation (4.0 ± 2.3 %W; control subjects = 2.4 ± 0.9 %W, P < 0.013). After vitrectomy, contrast sensitivity function normalized in each case at 1 week (2.0 ± 1.4 %W, P < 0.01) and remained normal at 1 month (2.0 ± 1.0 %W, P < 0.003) and 3 months to 9 months (2.2 ± 1.5 %W, P < 0.018). Visual Function Questionnaire was 28.3% lower in floater patients (73.2 ± 15.6, N = 16) than in age-matched control subjects (93.9 ± 8.0, N = 12, P < 0.001), and postoperatively improved by 29.2% (P < 0.001). In the safety study of 60 floater cases treated with vitrectomy, none developed retinal breaks, infection, or glaucoma after a mean follow-up of 17.5 months. Only 8 of 34 cases (23.5%) required cataract surgery (none younger than 53 years) at an average of 15 months postvitrectomy. CONCLUSION Floaters lower contrast sensitivity function, which normalizes after vitrectomy. Visual Function Questionnaire quantified improvement in satisfaction. Not inducing posterior vitreous detachment reduced retinal tear incidence from 30% to 0% (P < 0.007). Postvitrectomy cataract incidence was reduced from 50% to 23.5% (P < 0.02). This approach thus seems effective and safe in alleviating the visual dysfunction induced by floaters.
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Filas BA, Shah NS, Zhang Q, Shui YB, Lake SP, Beebe DC. Quantitative imaging of enzymatic vitreolysis-induced fiber remodeling. Invest Ophthalmol Vis Sci 2014; 55:8626-37. [PMID: 25468895 DOI: 10.1167/iovs.14-15225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
PURPOSE Collagen fiber remodeling in the vitreous body has been implicated in cases of vitreomacular traction, macular hole, and retinal detachment, and also may occur during pharmacologic vitreolysis. The purpose of this study was to evaluate quantitative polarized light imaging (QPLI) as a tool for studying fiber organization in the vitreous and near the vitreoretinal interface in control and enzymatically perturbed conditions. METHODS Fiber alignment was measured in anterior-posterior sections of bovine and porcine vitreous. Additional tests were performed on bovine lenses and nasal-temporal vitreous sections. Effects of proteoglycan degradation on collagen fiber alignment using trypsin and plasmin were assessed at the microstructural level using electron microscopy and at the global level using QPLI. RESULTS Control vitreous showed fiber organization patterns consistent with the literature across multiple-length scales, including the global anterior-posterior coursing of vitreous fibers, as well as local fibers parallel to the equatorial vitreoretinal interface and transverse to the posterior interface. Proteoglycan digestion with trypsin or plasmin significantly increased fiber alignment throughout the vitreous (P < 0.01). The largest changes (3×) occurred in the posterior vitreous where fibers are aligned transverse to the posterior vitreoretinal interface (P < 0.01). CONCLUSIONS Proteoglycan loss due to enzymatic vitreolysis differentially increases fiber alignment at locations where tractions are most common. We hypothesize that a similar mechanism leads to retinal complications during age-related vitreous degeneration. Structural changes to the entire vitreous body (as opposed to the vitreoretinal interface alone) should be evaluated during preclinical testing of pharmacological vitreolysis candidates.
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Affiliation(s)
- Benjamen A Filas
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Nihar S Shah
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Qianru Zhang
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States Eye Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ying-Bo Shui
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Spencer P Lake
- Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, Missouri, United States
| | - David C Beebe
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States
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Zhang Q, Filas BA, Roth R, Heuser J, Ma N, Sharma S, Panitch A, Beebe DC, Shui YB. Preservation of the structure of enzymatically-degraded bovine vitreous using synthetic proteoglycan mimics. Invest Ophthalmol Vis Sci 2014; 55:8153-62. [PMID: 25342623 DOI: 10.1167/iovs.14-14366] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
PURPOSE Vitreous liquefaction and subsequent posterior vitreous detachment can lead to several sight-threatening diseases, including retinal detachment, macular hole and macular traction syndrome, nuclear cataracts, and possibly, open-angle glaucoma. In this study, we tested the ability of three novel synthetic chondroitin sulfate proteoglycan mimics to preserve the structure and physical properties of enzymatically-degraded bovine vitreous. METHODS Chondroitin sulfate proteoglycan mimics, designed to bind to type II collagen, hyaluronic acid, or both, were applied to trypsin- or collagenase-treated bovine vitreous in situ and in vitro. Rheology and liquefaction tests were performed to determine the physical properties of the vitreous, while Western blots were used to detect the presence and degradation of soluble collagen II (α1). Deep-etch electron microscopy (DEEM) identified the ultrastructure of mimic-treated and untreated enzyme-degraded bovine vitreous. RESULTS Proteoglycan mimics preserved the physical properties of trypsin-degraded bovine vitreous and protected against vitreous liquefaction. Although the collagen-binding mimic maintained the physical properties of collagenase-treated vitreous, liquefaction still occurred. Western blots indicated that the mimic provided only marginal protective ability against soluble collagen degradation. Deep-etch electron microscopy, however, showed increased density and isotropy of microstructural components in mimic-treated vitreous, supporting the initial result that vitreous structure was preserved. CONCLUSIONS Proteoglycan mimics preserved bovine vitreous physical properties after enzymatic degradation. These compounds may be useful in delaying or preventing the pathological effects of age-related, or enzymatically-induced, degradation of the vitreous body.
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Affiliation(s)
- Qianru Zhang
- Eye Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Benjamen A Filas
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Robyn Roth
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States
| | - John Heuser
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Nan Ma
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States Department of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Shaili Sharma
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States
| | - Alyssa Panitch
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States
| | - David C Beebe
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Ying-Bo Shui
- Department of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, United States
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Abstract
Purpose To evaluate the incidence and prevalence of cataract formation, progression, and extraction in patients that underwent vitreoretinal procedures and to evaluate factors that can potentially predispose patients to postoperative cataracts. Materials and methods The medical records of consecutive patients who underwent vitreoretinal surgery at the Yale Eye Center with at least 6 months of follow-up and no prior intraocular surgery were obtained. Preoperative, intraoperative, and postoperative data were recorded and analyzed in this retrospective observational study. The main outcome measures were defined as cataract extraction, formation, and progression after vitreoretinal procedures. The lens status of the surgical eye was recorded preoperatively and at 1 month, 3 months, 6 months, 12 months, 24 months, and 36 months postoperatively. Results A total of 193 eyes of 180 patients fulfilled the inclusion criteria. The percentages of eyes with mild lens change were 96% after 20-gauge pars plana vitrectomy (PPV), 72% after small gauge (23- and 25-gauge) PPV, 38% after scleral buckle (SB), 38% after pneumatic retinopexy (PR), and 91% after PPV plus SB (PPV+SB). Posterior subcapsular and nuclear sclerotic cataracts were the most common with almost all developing within 24 months. There was no statistically significant difference (P=1.00) between the rate of cataract extraction after 20-gauge (41%) and small gauge PPV (42%), but there was a statistically significant difference between PPV and non-PPV (SB, 6%; PR, 7%; P<0.001) and PPV and PPV+SB groups (69%; P=0.0063). Conclusion Cataracts were common following PPV regardless of the gauge. SB and PR led to the lowest while PPV+SB led to the highest risk of postoperative cataracts.
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Affiliation(s)
- Hao Feng
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT, USA
| | - Ron A Adelman
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT, USA
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Hammond BR, Johnson BA, George ER. Oxidative photodegradation of ocular tissues: beneficial effects of filtering and exogenous antioxidants. Exp Eye Res 2014; 129:135-50. [PMID: 25236792 DOI: 10.1016/j.exer.2014.09.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/11/2014] [Accepted: 09/13/2014] [Indexed: 01/17/2023]
Abstract
The fact that light is necessary for life is generally accepted as an axiom. The extent to which light interacts and influences human biology, however, is often not fully appreciated. Exposure to sunlight, for instance, can both promote and degrade human health. There is now general scientific consensus that, although the eye evolved to respond to light, it is also damaged by excessive exposure. Light-mediated ocular damage is involved in the pathophysiology of many common forms of blindness. The type of ocular tissue damage induced by light exposure depends on the extent of exposure and wavelength. The tissues of the lens, cornea, and retina contain specific chemical moieties that have been proven to exhibit light-mediated oxidative degradation. Proteins and lipids present in the cornea, lens, and retina, meet all of the physical requirements known to initiate the process of oxidative photodegradation upon exposure to solar radiation. As such, different mechanisms have evolved in the lens, cornea, and retina to ameliorate such light-mediated oxidative damage. It appears, however, that such mechanisms are ill-matched to handle modern conditions: namely, poor diet and longer life-spans (and the degenerative diseases that accompany them). Hence, steps must be taken to protect the eye from the damaging effects of light. Preventative measures include minimizing actinic light exposure, providing exogenous filtering (e.g., through the use of protective lenses), and enhancing antioxidant defenses (e.g., through increased dietary intake of antioxidants). These strategies may yield long-term benefits in terms of reducing oxidative photodegradation of the ocular tissues.
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Affiliation(s)
- Billy R Hammond
- Vision Sciences Laboratory, University of Georgia, Athens, GA 30602-3013, USA.
| | - Bart A Johnson
- Johnson & Johnson Vision Care, Inc., 7500 Centurion Parkway, R&D 3rd Floor W3A, Jacksonville, FL 33256, USA
| | - Eric R George
- Johnson & Johnson Vision Care, Inc., 7500 Centurion Parkway, R&D 3rd Floor W3A, Jacksonville, FL 33256, USA.
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Thanos S, Böhm MR, Meyer zu Hörste M, Prokosch-Willing V, Hennig M, Bauer D, Heiligenhaus A. Role of crystallins in ocular neuroprotection and axonal regeneration. Prog Retin Eye Res 2014; 42:145-61. [DOI: 10.1016/j.preteyeres.2014.06.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/06/2014] [Accepted: 06/22/2014] [Indexed: 11/30/2022]
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