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Choquet H, Duot M, Herrera VA, Shrestha SK, Meyers TJ, Hoffmann TJ, Sangani PK, Lachke SA. Multi-tissue transcriptome-wide association study identifies novel candidate susceptibility genes for cataract. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1362350. [PMID: 38984127 PMCID: PMC11182099 DOI: 10.3389/fopht.2024.1362350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 04/01/2024] [Indexed: 07/11/2024]
Abstract
Introduction Cataract is the leading cause of blindness among the elderly worldwide. Twin and family studies support an important role for genetic factors in cataract susceptibility with heritability estimates up to 58%. To date, 55 loci for cataract have been identified by genome-wide association studies (GWAS), however, much work remains to identify the causal genes. Here, we conducted a transcriptome-wide association study (TWAS) of cataract to prioritize causal genes and identify novel ones, and examine the impact of their expression. Methods We performed tissue-specific and multi-tissue TWAS analyses to assess associations between imputed gene expression from 54 tissues (including 49 from the Genotype Tissue Expression (GTEx) Project v8) with cataract using FUSION software. Meta-analyzed GWAS summary statistics from 59,944 cataract cases and 478,571 controls, all of European ancestry and from two cohorts (GERA and UK Biobank) were used. We then examined the expression of the novel genes in the lens tissue using the iSyTE database. Results Across tissue-specific and multi-tissue analyses, we identified 99 genes for which genetically predicted gene expression was associated with cataract after correcting for multiple testing. Of these 99 genes, 20 (AC007773.1, ANKH, ASIP, ATP13A2, CAPZB, CEP95, COQ6, CREB1, CROCC, DDX5, EFEMP1, EIF2S2, ESRRB, GOSR2, HERC4, INSRR, NIPSNAP2, PICALM, SENP3, and SH3YL1) did not overlap with previously reported cataract-associated loci. Tissue-specific analysis identified 202 significant gene-tissue associations for cataract, of which 166 (82.2%), representing 9 unique genes, were attributed to the previously reported 11q13.3 locus. Tissue-enrichment analysis revealed that gastrointestinal tissues represented one of the highest proportions of the Bonferroni-significant gene-tissue associations (21.3%). Moreover, this gastrointestinal tissue type was the only anatomical category significantly enriched in our results, after correcting for the number of tissue donors and imputable genes for each reference panel. Finally, most of the novel cataract genes (e.g., Capzb) were robustly expressed in iSyTE lens data. Discussion Our results provide evidence of the utility of imputation-based TWAS approaches to characterize known GWAS risk loci and identify novel candidate genes that may increase our understanding of cataract etiology. Our findings also highlight the fact that expression of genes associated with cataract susceptibility is not necessarily restricted to lens tissue.
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Affiliation(s)
- Hélène Choquet
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, CA, United States
| | - Matthieu Duot
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
- The National Centre for Scientific Research (CNRS), IGDR (Institut de Génétique et Développement de Rennes) - Joint Research Units (UMR), Univ Rennes, Rennes, France
| | - Victor A Herrera
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, CA, United States
| | - Sanjaya K Shrestha
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
| | - Travis J Meyers
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, CA, United States
| | - Thomas J Hoffmann
- Institute for Human Genetics, University of California San Francisco (UCSF), San Francisco, CA, United States
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, United States
| | - Poorab K Sangani
- Department of Ophthalmology, KPNC, South San Francisco, CA, United States
| | - Salil A Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States
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Jiang C, Melles RB, Sangani P, Hoffmann TJ, Hysi PG, Glymour MM, Jorgenson E, Lachke SA, Choquet H. Association of Behavioral and Clinical Risk Factors With Cataract: A Two-Sample Mendelian Randomization Study. Invest Ophthalmol Vis Sci 2023; 64:19. [PMID: 37459064 PMCID: PMC10362921 DOI: 10.1167/iovs.64.10.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 06/26/2023] [Indexed: 07/20/2023] Open
Abstract
Purpose To investigate the association of genetically determined primary open-angle glaucoma (POAG), myopic refractive error (RE), type 2 diabetes (T2D), blood pressure (BP), body mass index (BMI), cigarette smoking, and alcohol consumption with the risk of age-related cataract. Methods To assess potential causal effects of clinical or behavioral factors on cataract risk, we conducted two-sample Mendelian randomization analyses. Genetic instruments, based on common genetic variants associated with risk factors at genome-wide significance (P < 5 × 10-8), were derived from published genome-wide association studies (GWAS). For age-related cataract, we used GWAS summary statistics from our previous GWAS conducted in the Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort (28,092 cataract cases and 50,487 controls; all non-Hispanic whites) or in the UK Biobank (31,852 cataract cases and 428,084 controls; all European-descent individuals). We used the inverse-variance weighted (IVW) method as our primary source of Mendelian randomization estimates and conducted common sensitivity analyses. Results We found that genetically determined POAG and mean spherical equivalent RE were significantly associated with cataract risk (IVW model: odds ratio [OR] = 1.04; 95% confidence interval [CI], 1.01-1.08; P = 0.018; per diopter more hyperopic: OR = 0.92; 95% CI, 0.89-0.93; P = 6.51 × 10-13, respectively). In contrast, genetically determined T2D, BP, BMI, cigarette smoking, or alcohol consumption were not associated with cataract risk (P > 0.05). Conclusions Our results provide evidence that genetic risks for POAG and myopia may be causal risk factors for age-related cataract. These results are consistent with previous observational studies reporting associations of myopia with cataract risk. This information may support population cataract risk stratification and screening strategies.
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Affiliation(s)
- Chen Jiang
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, California, United States
| | - Ronald B. Melles
- KPNC, Department of Ophthalmology, Redwood City, California, United States
| | - Poorab Sangani
- KPNC, Department of Ophthalmology, South San Francisco, California, United States
| | - Thomas J. Hoffmann
- Institute for Human Genetics, UCSF, San Francisco, California, United States
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, California, United States
| | - Pirro G. Hysi
- King's College London, Section of Ophthalmology, School of Life Course Sciences, London, United Kingdom
- King's College London, Department of Twin Research and Genetic Epidemiology, London, United Kingdom
- University College London, Great Ormond Street Hospital Institute of Child Health, London, United Kingdom
| | - M. Maria Glymour
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, California, United States
| | - Eric Jorgenson
- Regeneron Genetics Center, Tarrytown, New York, United States
| | - Salil A. Lachke
- Department of Biological Sciences, University of Delaware, Newark, Delaware, United States
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, United States
| | - Hélène Choquet
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, California, United States
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Ma B, Zhang W, Wang X, Jiang H, Tang L, Yang W, Kang Q, Cao J. Polymorphisms in TRIB2 and CAPRIN2 Genes Contribute to the Susceptibility to High Myopia-Induced Cataract in Han Chinese Population. Med Sci Monit 2023; 29:e937702. [PMID: 36710479 PMCID: PMC9896844 DOI: 10.12659/msm.937702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Myopia has been shown to be associated with many pathological complications including cataracts, and previous evidence supported that high myopia facilitates the formation of cataracts. However, no studies have identified a link between the genetic susceptibility of high myopia-induced cataracts (HMC) and the underlying genetic mechanisms. Our study aimed to determine how the TRIB2 and CAPRIN2 genes correlate to the risk of HMC. MATERIAL AND METHODS In total, we successfully recruited 3162 participants, including 1026 participants with high myopia and cataracts and 2136 controls with high myopia only. For genotyping, 22 tag single nucleotide polymorphisms (SNPs) in TRIB2 and CAPRIN2 genes were chosen. Single marker association analysis and functional effects of significant SNPs were carried out. RESULTS Strong correlation signals were captured for SNP rs890069 (χ²=22.13, P=2.55×10-6) in TRIB2 and SNP rs17739338 (χ²=16.07, P=6.10×10-5) in CAPRIN2. In patients with high myopia, the C allele at SNP rs890069 was strongly linked to cataract risk (OR [95% CI]=1.36 [1.20-1.55]). In patients with high myopia, the T allele at SNP rs17739338 was significantly related to a lower risk of cataract (OR [95% CI]=0.54 [0.40-0.74]). In different types of human tissues, SNPs rs890069 and rs17739338 were found to be significantly correlated to the levels of TRIB2 and CAPRIN2 gene expression. CONCLUSIONS Our study indicated that both TRIB2 and CAPRIN2 genes conferred the susceptibility to cataract in patients with high myopia and Chinese Han ancestry. Future research remains necessary for fully understanding the pathogenic mechanisms and genetic characteristics of cataract.
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Affiliation(s)
- Bo Ma
- Department of Ophthalmology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, PR China
| | - Wenpei Zhang
- Department of Forensic Medicine, School of Medicine and Forensics, Xi’an Jiaotong University, Xi’an, Shaanxi, PR China
| | - Xiaochen Wang
- Department of Forensic Medicine, School of Medicine and Forensics, Xi’an Jiaotong University, Xi’an, Shaanxi, PR China
| | - Huili Jiang
- Department of Ophthalmology, Xi’an Fourth Hospital, Xi’an, Shaanxi, PR China
| | - Li Tang
- Department of Ophthalmology, Xi’an Fourth Hospital, Xi’an, Shaanxi, PR China
| | - Wen Yang
- Department of Ophthalmology, Xi’an Fourth Hospital, Xi’an, Shaanxi, PR China
| | - Qianyan Kang
- Department of Ophthalmology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, PR China
| | - Juan Cao
- Department of Ophthalmology, Xi’an Fourth Hospital, Xi’an, Shaanxi, PR China
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Choquet H, Melles RB, Anand D, Yin J, Cuellar-Partida G, Wang W, Hoffmann TJ, Nair KS, Hysi PG, Lachke SA, Jorgenson E. A large multiethnic GWAS meta-analysis of cataract identifies new risk loci and sex-specific effects. Nat Commun 2021; 12:3595. [PMID: 34127677 PMCID: PMC8203611 DOI: 10.1038/s41467-021-23873-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 05/17/2021] [Indexed: 01/16/2023] Open
Abstract
Cataract is the leading cause of blindness among the elderly worldwide and cataract surgery is one of the most common operations performed in the United States. As the genetic etiology of cataract formation remains unclear, we conducted a multiethnic genome-wide association meta-analysis, combining results from the GERA and UK Biobank cohorts, and tested for replication in the 23andMe research cohort. We report 54 genome-wide significant loci, 37 of which were novel. Sex-stratified analyses identified CASP7 as an additional novel locus specific to women. We show that genes within or near 80% of the cataract-associated loci are significantly expressed and/or enriched-expressed in the mouse lens across various spatiotemporal stages as per iSyTE analysis. Furthermore, iSyTE shows 32 candidate genes in the associated loci have altered gene expression in 9 different gene perturbation mouse models of lens defects/cataract, suggesting their relevance to lens biology. Our work provides further insight into the complex genetic architecture of cataract susceptibility.
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Affiliation(s)
- Hélène Choquet
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, CA, USA.
| | | | - Deepti Anand
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Jie Yin
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, CA, USA
| | | | | | | | - Thomas J Hoffmann
- Institute for Human Genetics, UCSF, San Francisco, CA, USA.,Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, USA
| | - K Saidas Nair
- Departments of Ophthalmology and Anatomy, School of Medicine, UCSF, San Francisco, CA, USA
| | - Pirro G Hysi
- King's College London, Section of Ophthalmology, School of Life Course Sciences, London, UK.,King's College London, Department of Twin Research and Genetic Epidemiology, London, UK.,University College London, Great Ormond Street Hospital Institute of Child Health, London, UK
| | - Salil A Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE, USA.,Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, USA
| | - Eric Jorgenson
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, CA, USA
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Loomis SJ, Klein AP, Lee KE, Chen F, Bomotti S, Truitt B, Iyengar SK, Klein R, Klein BEK, Duggal P. Exome Array Analysis of Nuclear Lens Opacity. Ophthalmic Epidemiol 2017; 25:215-219. [PMID: 29182452 DOI: 10.1080/09286586.2017.1406122] [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] [Indexed: 02/07/2023]
Abstract
PURPOSE Nuclear cataract is the most common subtype of age-related cataract, the leading cause of blindness worldwide. It results from advanced nuclear sclerosis, or opacity in the center of the optic lens, and is affected by both genetic and environmental risk factors, including smoking. We sought to understand the genetic factors associated with nuclear sclerosis through interrogation of rare and low frequency coding variants using exome array data. METHODS We analyzed Illumina Human Exome Array data for 1,488 participants of European ancestry in the Beaver Dam Eye Study who were without cataract surgery for association with nuclear sclerosis grade, controlling for age and sex. We performed single-variant regression analysis for 32,138 variants with minor allele frequency (MAF) ≥0.003. In addition, gene-based analysis of 11,844 genes containing at least two variants with MAF < 0.05 was performed using a gene-based unified burden and non-burden sequence kernel association test (SKAT-O). Additionally, both single-variant and gene-based analyses were analyzed stratified by smoking status. RESULTS No single-variant test was statistically significant after Bonferroni correction (p < 1.6 × 10-6; top single nucleotide polymorphism (SNP): rs144458991, p = 2.83 × 10-5). Gene-based tests were suggestively associated with the gene RNF149 overall (p = 8.29 × 10-6) and among never smokers (N = 790, p = 2.67 × 10-6). CONCLUSIONS This study did not find a significant genetic association with nuclear sclerosis, the possible association with the RNF149 gene highlights a potential candidate gene for future studies that aim to understand the genetic architecture of nuclear sclerosis.
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Affiliation(s)
- Stephanie J Loomis
- a Department of Epidemiology , Johns Hopkins Bloomberg School of Public Health , Baltimore , MD , USA
| | - Alison P Klein
- a Department of Epidemiology , Johns Hopkins Bloomberg School of Public Health , Baltimore , MD , USA.,b Department of Oncology , Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins , Baltimore , MD , USA.,c Department of Pathology , Johns Hopkins School of Medicine , Baltimore , MD , USA
| | - Kristine E Lee
- d Department of Ophthalmology and Visual Sciences , University of Wisconsin School of Medicine and Public Health , Madison , WN , USA
| | - Fei Chen
- a Department of Epidemiology , Johns Hopkins Bloomberg School of Public Health , Baltimore , MD , USA
| | - Samantha Bomotti
- a Department of Epidemiology , Johns Hopkins Bloomberg School of Public Health , Baltimore , MD , USA
| | - Barbara Truitt
- e Department of Epidemiology and Biostatistics , Case Western Reserve University , Cleveland , OH , USA
| | - Sudha K Iyengar
- e Department of Epidemiology and Biostatistics , Case Western Reserve University , Cleveland , OH , USA
| | - Ronald Klein
- d Department of Ophthalmology and Visual Sciences , University of Wisconsin School of Medicine and Public Health , Madison , WN , USA
| | - Barbara E K Klein
- d Department of Ophthalmology and Visual Sciences , University of Wisconsin School of Medicine and Public Health , Madison , WN , USA
| | - Priya Duggal
- a Department of Epidemiology , Johns Hopkins Bloomberg School of Public Health , Baltimore , MD , USA
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Cui NH, Qiao C, Chang XK, Wei L. Associations of PARP-1 variant rs1136410 with PARP activities, oxidative DNA damage, and the risk of age-related cataract in a Chinese Han population: A two-stage case-control analysis. Gene 2016; 600:70-76. [PMID: 27840165 DOI: 10.1016/j.gene.2016.11.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 11/09/2016] [Indexed: 01/05/2023]
Abstract
OBJECTIVE To investigate whether a single nucleotide polymorphism (SNP) rs1136410 in the poly (ADP-ribose) polymerase-1 (PARP-1) gene was associated with PARP activities, 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, and the risk of age-related cataract (ARC) in a Chinese Han population. METHODS In this two-stage case-control study with a total of 1010 ARC patients and 1045 controls, SNP rs1136410 was genotyped by high-resolution melting analyses (HRM). PARP activities and 8-OHdG levels in peripheral blood mononuclear cells (PBMCs) were determined by ELISA kits. RESULTS In discovery, replication, and their merged sets, the variant genotypes (AG+GG) of SNP rs1136410 were significantly associated with an increased risk of ARC under a dominant model (Adjusted odds ratio (OR)=1.42, Padj=0.001 for the merged set). This association was further identified in subtype analyses for cortical ARC (Adjusted OR=1.69, Padj<0.001). In subgroup analyses, we identified a significant interaction between SNP rs1136410 and smoking habit in increasing ARC risk (Pinter=0.019). Moreover, ARC patients had lower activities of PARP and higher levels of 8-OHdG than controls. There were significant correlations of SNP rs1136410 with decreased PARP activities and increased 8-OHdG levels in controls and patients with cortical ARC. CONCLUSIONS This study suggests that SNP rs1136410 may confer susceptibility to ARC by affecting PARP activities and oxidative DNA damage.
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Affiliation(s)
- Ning-Hua Cui
- Department of Clinical Laboratory, Children's Hospital of Zhengzhou, Zhengzhou, Henan, China.
| | - Chen Qiao
- Department of Corneal, Hankou Aier Eye Hospital, Wuhan, Hubei, China
| | - Xiao-Ke Chang
- Department of Cataract, Hankou Aier Eye Hospital, Wuhan, Hubei, China
| | - Li Wei
- Department of Ophthalmology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China
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Kubota M, Shui YB, Liu M, Bai F, Huang AJ, Ma N, Beebe DC, Siegfried CJ. Mitochondrial oxygen metabolism in primary human lens epithelial cells: Association with age, diabetes and glaucoma. Free Radic Biol Med 2016; 97:513-519. [PMID: 27445101 PMCID: PMC4996752 DOI: 10.1016/j.freeradbiomed.2016.07.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 06/14/2016] [Accepted: 07/18/2016] [Indexed: 12/13/2022]
Abstract
PURPOSE The hypoxic environment around the lens is important for maintaining lens transparency. Lens epithelial cells (LECs) play a key role in lens metabolism. We measured oxygen consumption to assess the role of human LECs in maintaining hypoxia around the lens, as well as the impact of systemic and ocular diagnosis on these cells. METHODS Baseline cellular respiration was measured in rabbit LECs (NN1003A), canine kidney epithelial cells (MDCK), trabecular meshwork cells (TM-5), and bovine corneal endothelial cells (CCEE) using a XF96 Extracellular Flux Analyzer (Seahorse Bioscience, North Billerica, MA), which measures oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in vitro. Following informed written consent, lens capsule epithelial cells were obtained from patients during cataract surgery and were divided into small explants in 96-well plates. Capsules were removed when LECs became confluent. OCR was normalized to the number of cells per well using rabbit LECs as a standard. The effect of patient age, sex, race, and presence of diabetes or glaucoma on oxygen consumption was assessed by using the Mann-Whitney U test and multivariate regression analysis. RESULTS Primary LECs were obtained from 69 patients. The OCR from donors aged 70 and over was lower than that of those under 70 years (2.21±1.037 vs. 2.86±1.383 fmol/min/cell; p<0.05). Diabetic patients had lower OCR than non-diabetic patients (2.02±0.911 vs. 2.79±1.332fmol/min/cell; p<0.05), and glaucoma patients had lower OCR than non-glaucoma patients (2.27±1.19 vs. 2.83±1.286 fmol/min/cell; p<0.05). Multivariate regression analysis confirmed that donors aged 70 and over (p<0.05), diabetic patients (p<0.01), and glaucoma patients (p<0.05) had significantly lower OCR, independent of other variables. Gender and race had no significant effect on OCR. CONCLUSIONS The lower oxygen consumption rate of human LECs in older donors and patients with diabetes or glaucoma could contribute to cataract development. Diabetes and glaucoma are particularly important factors associated with decreased OCR, independent of age. Ongoing studies are examining pO2 at the anterior surface of the lens in vivo and oxygen consumption in the patient's LECs.
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Affiliation(s)
- M Kubota
- Departments of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, United States; Departments of Ophthalmology, Keio University School of Medicine, Tokyo, Japan.
| | - Y B Shui
- Departments of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, United States.
| | - M Liu
- Departments of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, United States.
| | - F Bai
- Departments of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, United States.
| | - A J Huang
- Departments of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, United States.
| | - N Ma
- Departments of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, United States; Departments of Ophthalmology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.
| | - D C Beebe
- Departments of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, United States; Departments of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States
| | - C J Siegfried
- Departments of Ophthalmology & Visual Sciences, Washington University School of Medicine, St. Louis, MO, United States.
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Datiles MB, Ansari RR, Yoshida J, Brown H, Zambrano AI, Tian J, Vitale S, Zigler JS, Ferris FL, West SK, Stark WJ. Longitudinal Study of Age-Related Cataract Using Dynamic Light Scattering: Loss of α-Crystallin Leads to Nuclear Cataract Development. Ophthalmology 2016; 123:248-254. [PMID: 26545319 PMCID: PMC4724511 DOI: 10.1016/j.ophtha.2015.10.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 10/04/2015] [Accepted: 10/06/2015] [Indexed: 01/14/2023] Open
Abstract
PURPOSE To conduct a longitudinal study on age-related nuclear cataracts using dynamic light scattering (DLS) to determine if cataract progression is associated with loss of the unbound form of the lens molecular chaperone protein, α-crystallin. DESIGN Natural history and cohort study. PARTICIPANTS Patients 30 years of age or older of either gender seeking treatment at the Wilmer Eye Institute Cornea-Cataract Department. METHODS All patients underwent a comprehensive dilated eye examination every 6 months, including slit-lamp grading of their lenses using the Age-Related Eye Disease Study (AREDS) clinical lens grading system and obtaining an estimate of unbound α-crystallin level in the nucleus, the α-crystallin index (ACI), using the National Aeronautics and Space Administration-National Eye Institute DLS device. We used a random effects statistical model to examine the relationship of lens opacity changes over time with ACI changes. MAIN OUTCOME MEASURES α-Crystallin Index (ACI) and AREDS nuclear cataract grade. RESULTS Forty-five patients (66 eyes) 34 to 79 years of age with AREDS nuclear lens grades of 0 to 3.0 were followed up every 6 months for a mean of 19 months (range, 6-36 months). We found that lenses with the lowest baseline levels of ACI had the most rapid progression of cataracts, whereas lenses with higher ACI at baseline had no or slower cataract progression. Lenses that lost α-crystallin at the highest rates during the study also had faster progression of nuclear cataracts than lenses with a slower rate of ACI loss. Kaplan-Meier survival curves showed that lenses with the lowest initial ACI had the highest risk of undergoing cataract surgery. CONCLUSIONS This longitudinal study corroborates our previous cross-sectional study finding that higher levels of unbound α-crystallin as assessed by ACI are associated with lower risk of cataract formation and that loss of ACI over time is associated with cataract formation and progression. This study suggested that assessment of ACI with the DLS device could be used as a surrogate for lens opacity risk in clinical studies, and for assessing nuclear cataract events in studies where cataract development may be a side effect of a drug or device.
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Affiliation(s)
- Manuel B Datiles
- National Eye Institute, National Institutes of Health, Bethesda, Maryland.
| | - Rafat R Ansari
- National Aeronautics and Space Administration-John H. Glenn Research Center, Cleveland, Ohio
| | - Junko Yoshida
- The Wilmer Eye Institute, Johns Hopkins University Hospital, Baltimore, Maryland; Department of Ophthalmology, University of Tokyo, Tokyo, Japan
| | - Holly Brown
- The Wilmer Eye Institute, Johns Hopkins University Hospital, Baltimore, Maryland
| | - Andrea I Zambrano
- The Wilmer Eye Institute, Johns Hopkins University Hospital, Baltimore, Maryland
| | - Jing Tian
- The Wilmer Eye Institute, Johns Hopkins University Hospital, Baltimore, Maryland
| | - Susan Vitale
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - J Samuel Zigler
- The Wilmer Eye Institute, Johns Hopkins University Hospital, Baltimore, Maryland
| | - Frederick L Ferris
- National Eye Institute, National Institutes of Health, Bethesda, Maryland
| | - Sheila K West
- The Wilmer Eye Institute, Johns Hopkins University Hospital, Baltimore, Maryland
| | - Walter J Stark
- The Wilmer Eye Institute, Johns Hopkins University Hospital, Baltimore, Maryland
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Lin Q, Zhou N, Zhang N, Qi Y. Mutational screening of EFNA5 in Chinese age-related cataract patients. Ophthalmic Res 2014; 52:124-9. [PMID: 25300504 DOI: 10.1159/000363139] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 04/18/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIM In the past few years, Ephrin-A5 (EFNA5) had been identified to be associated with lens development, but so far no sequence variation in EFNA5 has been reported in humans. Therefore, we conduct this study to investigate the EFNA5 genetic variations in Chinese age-related cataract (ARC) patients. METHODS Sequencing of EFNA5 was performed in 140 sporadic ARC patients and 142 random unrelated healthy subjects. Genomic DNA was extracted from peripheral blood leukocytes. All exons of EFNA5 were sequenced after being amplified by polymerase chain reaction. The functional consequences of the variations were analyzed using PolyPhen2. RESULTS Three single nucleotide polymorphisms in EFNA5, c.668C>T (rs201008479), c.102C>T (rs199980747) and c.-27C>G (rs200187971), were found in the patients, and none of them presented in the normal controls. Using PolyPhen2, c.668C>T in EFNA5 is predicted to be possibly damaging. CONCLUSIONS The genetic variations c.668C>T (rs201008479), c.102C>T (rs199980747) and c.-27C>G (rs200187971) may present an additional genetic risk factor for ARC in the Chinese population. This study shows the first cases of these genetic variations in EFNA5 in human beings.
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Affiliation(s)
- Qinghong Lin
- Department of Ophthalmology, The Second Affiliated Hospital of Harbin Medical University, Harbin, PR China
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Ritchie MD, Verma SS, Hall MA, Goodloe RJ, Berg RL, Carrell DS, Carlson CS, Chen L, Crosslin DR, Denny JC, Jarvik G, Li R, Linneman JG, Pathak J, Peissig P, Rasmussen LV, Ramirez AH, Wang X, Wilke RA, Wolf WA, Torstenson ES, Turner SD, McCarty CA. Electronic medical records and genomics (eMERGE) network exploration in cataract: several new potential susceptibility loci. Mol Vis 2014; 20:1281-95. [PMID: 25352737 PMCID: PMC4168835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 09/17/2014] [Indexed: 10/27/2022] Open
Abstract
PURPOSE Cataract is the leading cause of blindness in the world, and in the United States accounts for approximately 60% of Medicare costs related to vision. The purpose of this study was to identify genetic markers for age-related cataract through a genome-wide association study (GWAS). METHODS In the electronic medical records and genomics (eMERGE) network, we ran an electronic phenotyping algorithm on individuals in each of five sites with electronic medical records linked to DNA biobanks. We performed a GWAS using 530,101 SNPs from the Illumina 660W-Quad in a total of 7,397 individuals (5,503 cases and 1,894 controls). We also performed an age-at-diagnosis case-only analysis. RESULTS We identified several statistically significant associations with age-related cataract (45 SNPs) as well as age at diagnosis (44 SNPs). The 45 SNPs associated with cataract at p<1×10(-5) are in several interesting genes, including ALDOB, MAP3K1, and MEF2C. All have potential biologic relationships with cataracts. CONCLUSIONS This is the first genome-wide association study of age-related cataract, and several regions of interest have been identified. The eMERGE network has pioneered the exploration of genomic associations in biobanks linked to electronic health records, and this study is another example of the utility of such resources. Explorations of age-related cataract including validation and replication of the association results identified herein are needed in future studies.
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Affiliation(s)
- Marylyn D. Ritchie
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA
| | - Shefali S. Verma
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA
| | - Molly A. Hall
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA
| | - Robert J. Goodloe
- Center for Human Genetics Research, Vanderbilt University, Nashville, TN
| | - Richard L. Berg
- Biomedical Informatics Research Center, Biostatistics, Marshfield Clinic Research Foundation, Marshfield, WI
| | | | | | - Lin Chen
- Ophthalmology, Marshfield Clinic Research Foundation, Marshfield, WI
| | - David R. Crosslin
- Division of Medical Genetics, University of Washington, Seattle, WA,Department of Biostatistics, University of Washington, Seattle, WA
| | - Joshua C. Denny
- Departments of Biomedical Informatics, Vanderbilt University, Nashville, TN,Department of Medicine, Vanderbilt University, Nashville, TN
| | - Gail Jarvik
- Division of Medical Genetics, University of Washington, Seattle, WA,Departments of Medicine and Genome Sciences, University of Washington, Seattle, WA
| | - Rongling Li
- Office of Population Genomics, National Human Genome Research Institute, Bethesda, MD
| | - James G. Linneman
- Biomedical Informatics Research Center, Marshfield Clinic Research Foundation, Marshfield, WI
| | - Jyoti Pathak
- Department of Biomedical Informatics, Mayo Clinic College of Medicine, Rochester, MN
| | - Peggy Peissig
- Biomedical Informatics Research Center, Marshfield Clinic Research Foundation, Marshfield, WI
| | - Luke V. Rasmussen
- Division of Health and Biomedical Informatics, Department of Preventive Medicine, Northwestern University, Chicago, IL
| | | | - Xiaoming Wang
- Departments of Biomedical Informatics, Vanderbilt University, Nashville, TN
| | - Russell A. Wilke
- Departments of Biomedical Informatics, Vanderbilt University, Nashville, TN,IMAGENETICS at Sanford Medical Center, Fargo, ND and Department of Internal Medicine, University of North Dakota, Fargo, ND
| | - Wendy A. Wolf
- Division of Genetics and Genomics, Boston Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, MA
| | - Eric S. Torstenson
- Center for Human Genetics Research, Vanderbilt University, Nashville, TN
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11
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Liao J, Su X, Chen P, Wang X, Xu L, Li X, Thean L, Tan C, Tan AG, Tay WT, Jun G, Zheng Y, Chew M, Wang YX, Tan QS, Barathi VA, Klein BE, Saw SM, Vithana EN, Tai ES, Iyengar SK, Mitchell P, Khor CC, Aung T, Wang JJ, Jonas JB, Teo YY, Wong TY, Cheng CY. Meta-analysis of genome-wide association studies in multiethnic Asians identifies two loci for age-related nuclear cataract. Hum Mol Genet 2014; 23:6119-28. [DOI: 10.1093/hmg/ddu315] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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12
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Sousounis K, Tsonis PA. Patterns of gene expression in microarrays and expressed sequence tags from normal and cataractous lenses. Hum Genomics 2012; 6:14. [PMID: 23244575 PMCID: PMC3563465 DOI: 10.1186/1479-7364-6-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 11/30/2022] Open
Abstract
In this contribution, we have examined the patterns of gene expression in normal and cataractous lenses as presented in five different papers using microarrays and expressed sequence tags. The purpose was to evaluate unique and common patterns of gene expression during development, aging and cataracts.
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Affiliation(s)
- Konstantinos Sousounis
- Department of Biology and Center for Tissue Regeneration and Engineering, University of Dayton, Dayton, OH 45469-2320, USA
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13
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Mehra S, Kapur S, Mittal S, Sehgal PK. Common genetic link between metabolic syndrome components and senile cataract. Free Radic Res 2012; 46:133-40. [PMID: 22165987 DOI: 10.3109/10715762.2011.645205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Relationship between cataract and metabolic syndrome (MetS) is well established, but genetic link remains to be explored. D2S439 at 2q37 linked with QTL controlling visceral fat was investigated for its association with senile cataract. Two hundred and twenty-seven subjects including 119 cataract cases were genotyped for D2S439, tetra nucleotide repeat marker. Statistical tools assessed the association of marker's allele with anthropometric, clinical and oxidation stress parameters. Cases with longer allele ≥ (CTAT)(12) repeats, differed significantly from controls (0.77 vs. 0.58, p < 0.0001). Cases with at least one longer allele had higher waist circumference (50% vs. 15%, p = 0.0090), hyper-triglyceridemia (28% vs. 11%), hypo-HDL cholesterolemia (80% vs. 74%) and high diastolic blood pressure (37% vs. 26%) when compared to cases bearing the shorter allele. Cataract subjects with at least one longer allele had significantly raised lipid peroxidation levels (p = 0.0095) and showed an increased risk for cataract (OR = 5.86, CI(95%) = 1.49-23.11, p = 0.0114) after controlling for dependent variables. This exploratory study suggests that presence of even a single longer allele of D2S439 is associated with both cataract and MetS components in Asian Indians, unraveling the existence of a shared genetic locus.
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Affiliation(s)
- Shipra Mehra
- Birla Institute of Technology and Science-Pilani, Hyderabad Campus, India
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14
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Tanchangya J, Geater AF. Use of traditional cooking fuels and the risk of young adult cataract in rural Bangladesh: a hospital-based case-control study. BMC Ophthalmol 2011; 11:16. [PMID: 21679452 PMCID: PMC3148558 DOI: 10.1186/1471-2415-11-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Accepted: 06/16/2011] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND This study aimed to investigate the independent relationship between the use of various traditional biomass cooking fuels and the occurrence of cataract in young adults in rural Bangladesh. METHODS A hospital-based age- and sex-matched case-control study incorporating two control groups was conducted. Cases were cataract patients aged 18 and 49 years diagnosed on the basis of any opacity of the crystalline lens or its capsule and visual acuity poorer than 6/18 on the Log Mar Visual Acuity Chart in either eye, or who had a pseudophakic lens as a result of cataract surgery within the previous 5 years. Non-eye-disease (NE) controls were selected from patients from ENT or Orthopaedics departments and non-cataract eye-disease (NC) controls from the Ophthalmology department. Data pertaining to history of exposure to various cooking fuels and to established risk factors for cataract were obtained by face-to-face interview and analyzed using conditional logistic regression. RESULTS Clean fuels were used by only 4% of subjects. A majority of males (64-80% depending on group) had never cooked, while the rest had used biomass cooking fuels, mainly wood/dry leaves, with only 6 having used rice straw and/or cow dung. All females of each group had used wood/dry leaves for cooking. Close to half had also used rice straw and/or cow dung. Among females, after controlling for family history of cataract and education and combining the two control groups, case status was shown to be significantly related to lifetime exposure to rice straw, fitted as a trend variable coded as never, ≤median of all exposed, >median of all exposed (OR=1.52, 95%CI 1.04-2.22), but not to lifetime exposure to wood/dry leaves. Case status among females showed an inverse association with ever use of cow dung as a cooking fuel (OR 0.43, 95%CI 0.22-0.81). CONCLUSIONS In this population, where cooking is almost exclusively done using biomass fuels, cases of young adult cataract among females were more likely to have had an increased lifetime exposure to cooking with rice straw fuel and not to have cooked using cow dung fuel. There is a possibility that these apparent associations could have been the result of uncontrolled founding, for instance by wealth. The nature of the associations, therefore, needs to be further investigated.
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Affiliation(s)
- Joydhan Tanchangya
- Impact "Jibon Tari" Floating Hospital, Impact Foundation Bangladesh, 7th Floor, House 23, Road 113/A, Gulshan-2, Dhaka-1212, Bangladesh
| | - Alan F Geater
- Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, 90112, Thailand
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15
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Shiels A, Bennett TM, Hejtmancik JF. Cat-Map: putting cataract on the map. Mol Vis 2010; 16:2007-15. [PMID: 21042563 PMCID: PMC2965572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 10/04/2010] [Indexed: 11/07/2022] Open
Abstract
Lens opacities, or cataract(s), may be inherited as a classic Mendelian disorder usually with early-onset or, more commonly, acquired with age as a multi-factorial or complex trait. Many genetic forms of cataract have been described in mice and other animal models. Considerable progress has been made in mapping and identifying the genes and mutations responsible for inherited forms of cataract, and genetic determinants of age-related cataract are beginning to be discovered. To provide a convenient and accurate summary of current information focused on the increasing genetic complexity of Mendelian and age-related cataract we have created an online chromosome map and reference database for cataract in humans and mice (Cat-Map).
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Affiliation(s)
- Alan Shiels
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO
| | - Thomas M. Bennett
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda MD
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16
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Sanfilippo PG, Hewitt AW, Hammond CJ, Mackey DA. The heritability of ocular traits. Surv Ophthalmol 2010; 55:561-83. [PMID: 20851442 DOI: 10.1016/j.survophthal.2010.07.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 07/23/2010] [Accepted: 07/27/2010] [Indexed: 12/17/2022]
Abstract
Heritability is the proportion of phenotypic variation in a population that is attributable to genetic variation among individuals. Many ophthalmic disorders and biometric traits are known to have a genetic basis and consequently much work has been published in the literature estimating the heritability of various ocular parameters. We collated and summarized the findings of heritability studies conducted in the field of ophthalmology. We grouped the various studies broadly by phenotype as follows: refraction, primary open-angle glaucoma, age-related macular degeneration (AMD), cataract, diabetic retinopathy, and others. A total of 82 articles were retrieved from the literature relating to estimation of heritability for an ocular disease or biometric trait; of these, 37 papers were concerned with glaucoma, 28 with refraction, 4 with AMD, 5 with diabetic retinopathy, and 4 with cataract. The highest reported heritability for an ophthalmic trait is 0.99 for the phenotype ≥ 20 small hard drusen, indicating that observed variation in this parameter is largely governed by genetic factors. Over 60% of the studies employed a twin study design and a similar percentage utilized variance components methods and structural equation modeling (SEM) to derive their heritability values. Using modern SEM techniques, heritability estimates derived from twin subjects were generally higher than those from family data. Many of the estimates are in the moderate to high range, but to date the majority of genetic variants accounting for these findings have not been uncovered, hence much work remains to be undertaken to elucidate fully their molecular etiology.
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Affiliation(s)
- Paul G Sanfilippo
- Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.
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17
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The EPHA2 gene is associated with cataracts linked to chromosome 1p. Mol Vis 2008; 14:2042-55. [PMID: 19005574 PMCID: PMC2582197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 11/07/2008] [Indexed: 11/03/2022] Open
Abstract
PURPOSE Cataracts are a clinically and genetically heterogeneous disorder affecting the ocular lens, and the leading cause of treatable vision loss and blindness worldwide. Here we identify a novel gene linked with a rare autosomal dominant form of childhood cataracts segregating in a four generation pedigree, and further show that this gene is likely associated with much more common forms of age-related cataracts in a case-control cohort. METHODS Genomic DNA was prepared from blood leukocytes, and genotyping was performed by means of single nucleotide polymorphism (SNP) markers, and short tandem repeat (STR) markers. Linkage analyses were performed with the GeneHunter and MLINK programs, and association analyses were performed with the Haploview and Exemplar programs. Mutation detection was achieved by PCR amplification of exons and di-deoxy cycle-sequencing. RESULTS Genome-wide linkage analysis with SNP markers, identified a likely disease-haplotype interval on chromosome 1p (rs707455-[approximately 10 Mb]-rs477558). Linkage to chromosome 1p was confirmed using STR markers D1S2672 (LOD score [Z]=3.56, recombination distance [theta]=0), and D1S2697 (Z=2.92, theta=0). Mutation profiling of positional-candidate genes detected a heterozygous transversion (c.2842G>T) in exon 17 of the gene coding for Eph-receptor type-A2 (EPHA2) that cosegregated with the disease. This missense change was predicted to result in the non-conservative substitution of a tryptophan residue for a phylogenetically conserved glycine residue at codon 948 (p.G948W), within a conserved cytoplasmic domain of the receptor. Candidate gene association analysis further identified SNPs in the EPHA2 region of chromosome 1p that were suggestively associated with age-related cataracts (p=0.007 for cortical cataracts, and p=0.01 for cortical and/or nuclear cataracts). CONCLUSIONS These data provide the first evidence that EPHA2, which functions in the Eph-ephrin bidirectional signaling pathway of mammalian cells, plays a vital role in maintaining lens transparency.
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18
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Bagchi M, Besser D, Reddy TR, Skoff R, Maisel H. Effect of thermal stress on early and late passaged mouse lens epithelial cells. J Cell Biochem 2007; 102:1036-42. [PMID: 17427954 DOI: 10.1002/jcb.21339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cataract is an age related disease of protein aggregation. It has been suggested that aging affects the cells ability to protect protein integrity. The protein integrity, which is essential for cellular homeostasis, is maintained by a complex system of refolding or degradation of damaged proteins. The heat shock proteins (hsps) are the major contributors in the maintenance of protein integrity. The heat shock transcription factor (HSF-1) is the master regulator of all hsp synthesis in response to stress. This investigation examined the role of HSF-1 in the regulation of hsp synthesis in early and late passaged alphaTN-4 cells. Data collected in this study revealed that the nucleotide sequence of HSF-1 mRNA obtained from early and late passaged alphaTN-4 cells were identical. When early and late passaged cell were exposed to thermal stress, their hsp expression were also similar. HSP-40 expression was detected after 2 h of heat stress, whereas HSP-70 and low molecular weight heat shock protein alphabeta crystallin showed significantly increased synthesis 18 h post heat stress. The late passaged alphaTN-4 cells ability to upregulate hsps in response to heat stress could be due to its high replicative activities. The data presented here suggests a relationship between the presence of functional HSF-1 and sustained proliferative activities of the late passaged alphaTN-4 cell.
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Affiliation(s)
- M Bagchi
- Department of Anatomy and Cell Biology, School of Medicine, Wayne State University, Detroit, Michigan 48201, USA.
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19
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Abstract
The purpose of this review is to highlight the advances made by epidemiologic research into cataract. Considerable progress has been made in characterizing phenotypes, determining the prevalence and incidence in various population groups, and understanding risk factors for cataract. Cataract surgery research has documented functional improvements following surgery and has identified aspects of surgery delivery that could be made. Cataract is an independent marker of early mortality, providing a possible system for studying the aging process. Promising future work in cataract epidemiology is highlighted. Despite the availability of cataract surgery, cataract is still the leading cause of blindness worldwide. From a public health standpoint, research that can identify ways to delay onset or progression, or achieve the holy grail of prevention of cataract, should remain a leading priority.
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Affiliation(s)
- Sheila West
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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20
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Chang MA, Congdon NG, Baker SK, Bloem MW, Savage H, Sommer A. The surgical management of cataract: barriers, best practices and outcomes. Int Ophthalmol 2007; 28:247-60. [PMID: 17712529 DOI: 10.1007/s10792-007-9121-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Accepted: 06/11/2007] [Indexed: 10/22/2022]
Abstract
Cataract is the leading cause of blindness in the world. Cataract surgery has been shown by multiple studies to be one of the most cost-effective health interventions, and leads to a dramatic increase in quality of life and productivity for many patients. Though there has been marked improvement in the last several decades, surgical delivery services in developing nations are still suboptimal, and a large backlog in cataract cases continues to grow. To decrease this backlog, barriers to surgery, such as direct and indirect patient costs, geographic access to surgical facilities and surgeons, cultural factors, and patient education, must be addressed. In particular, access to services by women and rural patients needs to be improved. It is clear that extracapsular techniques are cost-effective and lead to better post-operative outcomes than intracapsular cataract extraction with aphakic correction. In addition, monitoring surgical outcomes is essential for improving the quality of surgical services. However, other issues regarding the delivery of cataract surgical services, including the role of average power intraocular lenses and the role of non-physician surgeons, are yet unresolved. Information about the true cost of surgery, including costs of surgeon training, equipment, and patient outreach programs, is needed so that the goal of self-sustaining programs may be obtained.
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Affiliation(s)
- Margaret A Chang
- The Johns Hopkins University Schools of Medicine and Public Health, 600 N. Wolfe Street, Wilmer 120, Baltimore, MD 21287, USA.
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Abstract
PURPOSE This review aims to provide a literature survey of the association between photo-oxidation of lens proteins and lipid peroxidation with the genesis of age-related cataract in laboratory studies using rodent models, in epidemiological and interventional studies in humans. MATERIALS AND METHODS A Medline search using initial search terms lens, oxidation, antioxidant, and diet was employed to search for research papers covering the areas noted above from 1995 to 2005. Literature cited in those papers was also reviewed to provide as comprehensive a coverage of research work as possible. RESULTS Lens protein photo-oxidation and lipid peroxidation are widely acknowledged as important steps in age-related cataractogenesis. Dietary antioxidants are central in retarding cataractogenesis, although most evidence for this is gained from laboratory-based work on relatively unphysiologic rodent cataract models, using antioxidant regimes that could not be sustained in clinical practice. Most research in humans is retrospective epidemiology although some interventional research has been undertaken, with mixed results. CONCLUSIONS Dietary antioxidants are likely to be important in retarding cataractogenesis in older animals and in humans. Work on companion animals could provide a valuable stepping stone between rodent-based laboratory work and human interventional studies.
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Affiliation(s)
- David L Williams
- Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 OES, England, UK.
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Abstract
On the 65th anniversary of Gregg's observation "Congenital cataract following German measles in the mother", rubella has retired as the leading cause of congenital cataract, from 87% of Gregg's cohort to less than 3% over the last 25 years and almost zero now in Australia and other developed countries. However, people must keep vigilance in maintaining immunization rates and encourage immunization in developing countries. At least one-fifth of congenital cataract is familial. Understanding the genetics of familial cataract will lead to better treatment of congenital as well as age-related cataract.
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Affiliation(s)
- David A Mackey
- Eye Clinic, Royal Hobart Hospital, University of Tasmania, Hobart, Tasmania, Australia.
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Sparrow JM. Cataract in older women exposed to hormone replacement. Eye (Lond) 2006; 20:405-6. [PMID: 16604094 DOI: 10.1038/sj.eye.6701881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Abstract
AIMS To provide an update on the risk factors for cataract development. METHODS Review of the literature. RESULTS Age and heredity are the most important risk factors associated with the different types of cataract. While the hereditary component is self-explanatory, increasing age serves as a surrogate for a number of potential external risk factors, the effect of which is cumulative. Identification of the risk factors that have a causal effect on cataract development may provide means for cataract prevention. There are only a few risk factors that satisfy the criteria for causal effect: smoking, which results in the increased risk of nuclear cataract, excessive UV-B exposure and diabetes that increase the risk of cortical cataract, and steroidal treatment, diabetes and ionising radiation that lead to the formation of posterior subcapsular opacity. The effect of medications on cataract development requires further study, since the effect of the diseases should be distinguished from that of treatment. 'Stop Smoking' and 'UV-B protection' campaigns are gaining momentum as preventative measures, while the attempts to actively prevent cataract with antioxidants have not been successful. Cataract research has been facilitated lately by improvements of precision and standardisation in measuring lens opacities. However, measurement precision on its own cannot give us a solution to this problem. CONCLUSION The major studies repeatedly measure the exposure to the traditional health hazards, while the missing parts in the equation are those risk factors that we do not know about and therefore do not measure. New approaches and new hypotheses are needed.
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Affiliation(s)
- L Robman
- Centre for Eye Research Australia, University of Melbourne, East Melbourne, Australia.
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25
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Truscott RJW. Age-related nuclear cataract—oxidation is the key. Exp Eye Res 2005; 80:709-25. [PMID: 15862178 DOI: 10.1016/j.exer.2004.12.007] [Citation(s) in RCA: 561] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Revised: 11/22/2004] [Accepted: 12/03/2004] [Indexed: 11/26/2022]
Abstract
Age is by far the biggest risk factor for cataract, and it is sometimes assumed that cataract is simply an amplification of this aging process. This appears not to be the case, since the lens changes associated with aging and cataract are distinct. Oxidation is the hallmark of age-related nuclear (ARN) cataract. Loss of protein sulfhydryl groups, and the oxidation of methionine residues, are progressive and increase as the cataract worsens until >90% of cysteine and half the methionine residues are oxidised in the most advanced form. By contrast, there may be no significant oxidation of proteins in the centre of the lens with advancing age, even past age 80. The key factor in preventing oxidation seems to be the concentration of nuclear glutathione (GSH). Provided that nuclear GSH levels can be maintained above 2 mm, it appears that significant protein oxidation and posttranslational modification by reactive small molecules, such as ascorbate or UV filter degradation products, is not observed. Adequate coupling of the metabolically-active cortex, the source of antioxidants such as GSH, to the quiescent nucleus, is crucial especially since it would appear that the cortex remains viable in old lenses, and even possibly in ARN cataract lenses. Therefore it is vital to understand the reason for the onset of the lens barrier. This barrier, which becomes apparent in middle age, acts to impede the flow of small molecules between the cortex and the nucleus. The barrier, rather than nuclear compaction (which is not observed in human lenses), may contribute to the lowered concentration of GSH in the lens nucleus after middle age. By extending the residence time within the lens centre, the barrier also facilitates the decomposition of intrinsically unstable metabolites and may exacerbate the formation of H(2)O(2) in the nucleus. This hypothesis, which is based on the generation of reactive oxygen species and reactive molecules within the nucleus itself, shifts the focus away from theories for cataract that postulated a primary role for oxidants generated outside of the lens. Unfortunately, due to marked variability in the lenses of different species, there appears at present to be no ideal animal model system for studying human ARN cataract.
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Affiliation(s)
- Roger J W Truscott
- Australian Cataract Research Foundation, University of Wollongong, Northfields Ave, Wollongong, NSW 2522, Australia.
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Congdon N, Broman KW, Lai H, Munoz B, Bowie H, Gilbert D, Wojciechowski R, West SK. Cortical, but not posterior subcapsular, cataract shows significant familial aggregation in an older population after adjustment for possible shared environmental factors. Ophthalmology 2005; 112:73-7. [PMID: 15629823 PMCID: PMC3102010 DOI: 10.1016/j.ophtha.2004.07.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2004] [Accepted: 07/01/2004] [Indexed: 10/26/2022] Open
Abstract
PURPOSE To quantify the risk for age-related cortical cataract and posterior subcapsular cataract (PSC) associated with having an affected sibling after adjusting for known environmental and personal risk factors. DESIGN Sibling cohort study. PARTICIPANTS Participants in the ongoing Salisbury Eye Evaluation (SEE) study (n = 321; mean age, 78.1+/-4.2 years) and their locally resident siblings (n = 453; mean age, 72.6+/-7.4 years) were recruited at the time of Rounds 3 and 4 of the SEE study. INTERVENTION/TESTING METHODS: Retroillumination photographs of the lens were graded for the presence of cortical cataract and PSC with the Wilmer grading system. The residual correlation between siblings' cataract grades was estimated after adjustment for a number of factors (age; gender; race; lifetime exposure to ultraviolet-B light; cigarette, alcohol, estrogen, and steroid use; serum antioxidants; history of diabetes; blood pressure; and body mass index) suspected to be associated with the presence of cataract. RESULTS The average sibship size was 2.7 per family. Multivariate analysis revealed the magnitude of heritability (h(2)) for cortical cataract to be 24% (95% CI, 6%-42%), whereas that for PSC was not statistically significant (h(2) 4%; 95% CI, 0%-11%) after adjustment for the covariates. The model revealed that increasing age, female gender, a history of diabetes, and black race increased the odds of cortical cataract, whereas higher levels of provitamin A were protective. A history of diabetes and steroid use increased the odds for PSC. CONCLUSIONS This study is consistent with a significant genetic effect for age-related cortical cataract but not PSC.
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Affiliation(s)
- Nathan Congdon
- The Johns Hopkins University Schools of Medicine and Public Health, Baltimore, Maryland, USA.
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Wojciechowski R, Congdon N, Bowie H, Munoz B, Gilbert D, West S. Familial aggregation of hyperopia in an elderly population of siblings in Salisbury, Maryland. Ophthalmology 2005; 112:78-83. [PMID: 15629824 PMCID: PMC3102574 DOI: 10.1016/j.ophtha.2004.07.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Accepted: 07/15/2004] [Indexed: 12/31/2022] Open
Abstract
PURPOSE To determine whether hyperopia aggregates in families in an older mixed-race population. DESIGN Cross-sectional familial aggregation study using sibships. METHODS We recruited 759 subjects (mean age, 73.4 years) in 241 families through the population-based Salisbury Eye Evaluation study. Subjects underwent noncycloplegic refraction if best-corrected visual acuity (BCVA) was 20/40 with spectacles, or were considered to be plano (refraction of zero) if the BCVA was >20/40 without spectacles. Preoperative refraction from medical records was used for bilaterally pseudophakic subjects. RESULTS Utilizing hyperopia cutoffs from 1.00 to 2.50 diopters, age-, race-, and gender-adjusted odds ratios for hyperopia with an affected sibling ranged from 2.72 (95% confidence interval [CI], 1.84-4.01) to 4.87 (95% CI, 2.54-9.30). The odds of hyperopia increased with age until 75 years, after which they remained relatively constant. Black men were significantly less likely to be hyperopic than white men, white women, or black women. CONCLUSIONS Hyperopia appears to be under strong genetic control in this older population.
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Affiliation(s)
- Robert Wojciechowski
- Johns Hopkins University School of Medicine and Public Health, Baltimore, Maryland, USA
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Lewis A, Congdon N, Munoz B, Bowie H, Lai H, Chen P, West SK. Cataract surgery and subtype in a defined, older population: the SEECAT Project. Br J Ophthalmol 2004; 88:1512-7. [PMID: 15548802 PMCID: PMC1772435 DOI: 10.1136/bjo.2004.045484] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2004] [Indexed: 11/04/2022]
Abstract
AIM To describe the distribution of cataract subtypes present before surgery among a defined population of older, bilaterally pseudophakic individuals. METHODS This was a cohort study of bilaterally pseudophakic individuals participating in the Salisbury Eye Evaluation (SEE), and their locally resident siblings. Subjects underwent slit lamp and retroillumination photography and grading using the Wilmer Cataract Grading System. For all individuals determined to be bilaterally pseudophakic, an attempt was made to determine for each eye the type(s) of cataract present before surgery, based on previous SEE photographs (for SEE participants) and/or medical records obtained from the operating ophthalmologist (for both SEE participants and their siblings). RESULTS The mean age of 223 participants providing data in this study was 78.7 (SD 5.2) years, 19.3% of subjects were black and 60.1% female. The most common surgically removed cataract subtype in this population was pure nuclear (43.5%), followed by nuclear combined with posterior subcapsular cataract (PSC) (20.6%), and nuclear combined with cortical (13.9%); less common types were pure cortical (4.9%), pure PSC (4.5%), and PSC combined with cortical (2.7%). Factors such as sex and source of lens data (study photograph versus clinical record) did not significantly affect the distribution of lens opacity types, while PSC was significantly (p = 0.01) more common among younger people and nuclear cataract was significantly (p = 0.001) more common among white compared to black people. CONCLUSION Epidemiological studies have suggested that the different subtypes of cataract are associated with different risk factors. As studies begin to identify new prevention strategies for cataract, it would appear likely that different strategies will be efficacious against different types of cataract. In this setting, it will be helpful to know which cataract types are most frequently associated with surgery. Among this older, majority white population, nuclear cataract showed a clear predominance among individuals having undergone surgery in both eyes. This may be contrasted with both clinic and population based studies of younger people, which have generally found PSC cataract to predominate.
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Affiliation(s)
- A Lewis
- Dana Center for Preventive Ophthalmology, Johns Hopkins University Schools of Medicine and Public Health, Wilmer 120, 600 N Wolfe Street, Baltimore, MD 21287, USA
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