Katharina E. Schmid-Kubista

E2-2 protein and Fuchs's corneal dystrophy

BACKGROUND Fuchss corneal dystrophy (FCD) is a leading cause of corneal transplantation and affects 5% of persons in the United States who are over the age of 40 years. Clinically visible deposits called guttae develop under the corneal endothelium in patients with FCD. A loss of endothelial cells and deposition of an abnormal extracellular matrix are observed microscopically. In advanced disease, the cornea swells and becomes cloudy because the remaining endothelial cells are not sufficient to keep the cornea dehydrated and clear. Although rare genetic variation that contributes to both early-onset and typical late-onset forms of FCD has been identified, to our knowledge, no common variants have been reported. METHODS We performed a genomewide association study and replicated the most significant observations in a second, independent group of subjects. RESULTS Alleles in the transcription factor 4 gene (TCF4), encoding a member of the E-protein family (E2-2), were associated with typical FCD (P=2.3x10(-26)). The association increased the odds of having FCD by a factor of 30 for persons with two copies of the disease variants (homozygotes) and discriminated between case subjects and control subjects with about 76% accuracy. At least two regions of the TCF4 locus were associated independently with FCD. Alleles in the gene encoding protein tyrosine phosphatase receptor type G (PTPRG) were associated with FCD (P=4.0x10(-7)), but the association did not reach genomewide significance. CONCLUSIONS Genetic variation in TCF4 contributes to the development of FCD. (Funded by the National Eye Institute and others.)

Genetic control of the alternative pathway of complement in humans and age-related macular degeneration

Activation of the alternative pathway of complement is implicated in common neurodegenerative diseases including age-related macular degeneration (AMD). We explored the impact of common variation in genes encoding proteins of the alternative pathway on complement activation in human blood and in AMD. Genetic variation across the genes encoding complement factor H (CFH), factor B (CFB) and component 3 (C3) was determined. The influence of common haplotypes defining transcriptional and translational units on complement activation in blood was determined in a quantitative genomic association study. Individual haplotypes in CFH and CFB were associated with distinct and novel effects on plasma levels of precursors, regulators and activation products of the alternative pathway of complement in human blood. Further, genetic variation in CFH thought to influence cell surface regulation of complement did not alter plasma complement levels in human blood. Plasma markers of chronic activation (split-products Ba and C3d) and an activating enzyme (factor D) were elevated in AMD subjects. Most of the elevation in AMD was accounted for by the genetic variation controlling complement activation in human blood. Activation of the alternative pathway of complement in blood is under genetic control and increases with age. The genetic variation associated with increased activation of complement in human blood also increased the risk of AMD. Our data are consistent with a disease model in which genetic variation in the complement system increases the risk of AMD by a combination of systemic complement activation and abnormal regulation of complement activation in local tissues.

Correlation of different circulating endothelial progenitor cells to stages of diabetic retinopathy: first in vivo data.

PURPOSE To investigate vasculogenic circulating progenitor cells (CPCs), endothelial progenitor cells (EPCs), and mature EPCs in patients with type 1 diabetes mellitus (T1DM) with or without diabetic retinopathy (DR). METHODS A case-control study comparing 90 patients with T1DM with and without DR was performed. Patients were studied and staged for retinopathy according to the Early Treatment of Diabetic Retinopathy Study (ETDRS) classification. Ninety patients were included: 30 without DR (control [CO]), 30 with mild nonproliferative DR (mNPDR), 10 with moderate-severe NPDR (msNPDR), 10 with mild-moderate proliferative diabetic retinopathy (mmPDR), and 10 with high-risk PDR (hrPDR). CPCs (CD34/CD133), EPCs (CD34/CD133/CD309), and mature EPCs (CD34/CD133/CD309/CD31) were enumerated by flow cytometry. RESULTS EPCs were reduced in mNPDR (114 +/- 66; P < 0.001) and msNPDR (77 +/- 40; P = 0.042) compared with CO (244 +/- 115). In contrast, EPCs were unchanged in mmPDR (248 +/- 155) compared with CO. Strikingly, EPCs were augmented in hrPDR (389 +/- 124) compared with all other stages. Numbers of undifferentiated progenitor cells (CPCs) did not differ among CO, mmPDR, and hrPDR. Augmentation (3x) of mature EPCs in hrPDR (325 +/- 118; P < 0.001) compared with CO (100 +/- 49) but against all other stages of DR was observed. The percentage of mature EPCs/EPCs was augmented in an ETDRS classification-dependent manner. CONCLUSIONS In patients with T1DM with DR, EPCs undergo stage-related regulation. In nonproliferative retinopathy, a reduction of EPCs was observed, and in proliferative retinopathy, a dramatic increase of mature EPCs was observed.

Contribution of copy number variation in the regulation of complement activation locus to development of age-related macular degeneration.

PURPOSE To develop an assay for determining the number of copies of the genes encoding complement factor H related 3 (CFHR3) and 1 (CFHR1) and determine the contribution of copy number variation (CNV) at CFHR3 and CFHR1 to the development of age-related macular degeneration (AMD). METHODS A multiplex ligation-dependent probe amplification (MLPA) assay was developed to quantify the number of copies of CFHR3 and CFHR1 in humans. Subjects with (n = 252) and without (n = 249) AMD were genotyped using the assay, and the impact on AMD risk was evaluated. RESULTS The MLPA assay provided a consistent estimate of the number of copies of CFHR3 and CFHR1 in 500 of the 501 samples. Four different combinations of CNVs were observed with frequencies as follows: both CFHR3 and CFHR1 deletion (14%), CFHR3-only deletion (0.4%), CFHR1-only deletion (1.1%), and CFHR1 duplication (0.1%). Deletion of both copies of CFHR3 and CFHR1 decreased the odds of having AMD eightfold (95% CI 2-36) and always occurred on a protective haplotype, never on the risk haplotype tagged by the Y402H risk allele in CFH. The protection conferred by deletion of CFHR3 and CFHR1 could not be distinguished from the absence of the risk haplotype. CONCLUSIONS Both deletions and duplications of genes in the regulation of complement activation locus segregated in Caucasians. Deletion of CFHR3 and CFHR1 protected against the development of AMD at least in part because the deletion tagged a protective haplotype and did not occur on the risk haplotype.

Circulating Angiopoietic Cells and Diabetic Retinopathy in Type 2 Diabetes Mellitus, with or without Macrovascular Disease

PURPOSE To investigate different types of circulating angiopoietic cells, such as vasculogenic circulating progenitor cells (CPCs), endothelial progenitor cells (EPCs), and mature EPCs (matEPCs) in patients with type 2 diabetes mellitus (T2DM), with or without diabetic retinopathy (DR) and with or without macrovascular disease (MVD). METHODS One hundred twenty-six patients with T2DM-66 with MVD and 60 without MVD-were enrolled in a case-control study. MVD comprised coronary heart disease, peripheral arterial disease, stroke, or various combinations of those conditions. By a modified Early Treatment of Diabetic Retinopathy Study (ETDRS) classification, 55 patients were classified without DR (CO), 19 with mild nonproliferative DR (mNPDR), 16 with moderate-severe NPDR (msNPDR), 19 with early proliferative diabetic retinopathy (ePDR), and 17 with high-risk PDR (hrPDR). CPCs (CD34/CD133), EPCs (CD34/CD133/CD30), and matEPCs (CD34/CD133/CD309/CD31) were enumerated by flow cytometry. RESULTS Patients with MVD CPCs, EPCs, and matEPCs showed a significant, stepwise decline with advancing stages of retinopathy. In contrast, in the patients without MVD, EPCs and matEPCs reached up to 56% of CPCs and 37% of EPCs. On the other hand, the percentage of EPCs and matEPCs was reduced to 5% of CPCs and EPCs each in MVD patients. Thus, the percentage of EPCs and matEPCs in comparison with that of CPCs and EPCs represented an 11- and 7-fold difference. CONCLUSIONS The circulating angiopoietic CPCs, EPCs, and matEPCs in T2DM patients with DR had a different regulations, with increasing relative differences occurring in proliferative DR, apparently depending on the macrovascular comorbidities. Patients with MVD showed a strong retinopathy-stage-dependent depletion of all angiopoietic cells.

Systemic bevacizumab (Avastin) therapy for exudative neovascular age-related macular degeneration. The BEAT-AMD-Study

Background: Double-blinded, randomised, prospective, pilot-study to determine the effect of systemic bevacizumab therapy. Methods: Subjects with fibrovascular pigment epithelial detachment, subfoveal choroidal neovascularisation extending under the geometric centre of the foveal avascular zone and/or macular thickness of at least 300 μm in both eyes were included. Sixteen eyes were included and randomised equally to receive either three infusions of 5 mg/kg Avastin or 100 ml of 0.9% sodium chloride every 2 weeks. The main outcome measure was the lesion size. The follow-up time was 24 weeks. Results: Throughout the 24-week follow-up, the lesion size and macular thickness decreased in the Avastin group by 0.5 (SD 0.08) mm and 103.6 (14.9) μl respectively. In both groups, visual acuity remained stable in seven eyes and decreased in one eye. At the end of follow-up, 50% of the eyes in the Avastin group became fibrotic, 37.5% remained unchanged, and 12.5% developed a subretinal bleeding. There was a treatable rise in blood pressure after Avastin treatment. Conclusion: Systemic Avastin could be offered to patients with exudative age-related macular degeneration in both eyes and/or patients who refuse intravitreal injections if blood pressure is normal and there is no history of thrombosis.

Serum VEGF and CFH in Exudative Age-Related Macular Degeneration

Purpose: To determine serum vascular endothelial growth factor 165 (VEGF165) levels and the association of the complement factor H gene (CFH) Y402H polymorphism in patients with exudative age-related macular degeneration (AMD) in comparison to unaffected control subjects. Methods: Sixty-six AMD patients and 66 healthy age- and gender-matched controls were included in this case-control study. The serum VEGF165 was assayed by ELISA (R&D). Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism analysis. Chi-squared tests were used regarding the polymorphism, a t-test regarding the VEGF-levels. Results: Levels of serum VEGF165 were similar in both groups (p-value = 0.2112). Genotype frequency differed significantly between patients with exudative AMD and the healthy control group (p  =  0.003136). The serum VEGF165 levels were similar irrespective of the presence of the CFH Y402H polymorphism (p  =  0.4113) and independent of the specific genotype (p  =  0.9634). Conclusion: In the present study, exudative AMD is not associated to serum VEGF165 levels; furthermore, our data does not establish a statistical link between VEGF165 and the CFH Y402H polymorphism.

Comparing treatment of neovascular age-related macular degeneration with sequential intravitreal Avastin and Macugen versus intravitreal mono-therapy--a pilot study.

Purpose: To examine if the sequential treatment of Avastin and Macugen is safe and more efficient than the mono-therapies in a prospective randomized masked pilot study. Materials and Methods: Subjects with exudative age-related macular degeneration were randomized to receive three intravitreal injections of either 1 mg of Avastin, 0.3 mg Macugen, or first 1 mg Avastin followed by retreatment of 0.3 mg Macugen. Follow-up examinations were performed after 1, 6, 12 weeks, and 6 months. Results: Forty-eight subjects were included (13:18:17). Avastin resulted in lasting significant changes in visual acuity at 6 weeks, increase in contrast sensitivity at 6 weeks, and a significant decrease in macular thickness after 6 and 12 weeks. Macugen showed a significant decrease in retinal thickness after 6 weeks, but a significant decrease in visual acuity after 6 months, and a significant decrease in contrast sensitivity after 12 weeks and 6 months. The sequential treatment showed a decrease in retinal thickness after 1 and 12 weeks. Conclusion: Avastin alone is more effective in increasing visual acuity and contrast sensitivity and decreasing retinal thickness, than Macugen or the sequential treatment. We conclude that the sequential treatment of Avastin with Macugen is safe, but the single treatment of Avastin is more efficient.

Effect of Work-Related Ultraviolet Exposure and Ophthalmic Changes in Austrian Farmers: The SVB-UV Study

Background: Epidemiological screening to examine possible ultraviolet-induced ocular changes and pathologies in Austrian farmers. Methods: The study was performed on behalf of the Austrian farmer insurance (Sozialversicherungsanstalt der Bauern). Randomly selected farmers and office workers as controls, both at the age of 35–55 years, underwent ophthalmic screening examinations. All subjects underwent complete ophthalmic examinations by slit lamp examination and Schirmer’s test 1. A survey, regarding per- sonal habits in the sun, was also conducted. Results: Three hundred and ninety-two subjects underwent ophthalmic examinations of whom 297 were farmers and 95 were controls. Due to the survey, 89.7% of the farmers claimed to protect themselves from the sun during work. From these subjects, 83.7% wear a head protection, 71.0% wear sunglasses, and 54.4% usually work in the shade. There were significant differences in lid (p = 0.021) and conjunctival pathologies (p < 0.0001) between farmers and controls. Conclusion: Austrian farmers are at a higher risk for developing lid and conjunctival tumours which require treatment at some point. We believe that the study group was too young to show significant differences within the lens and the posterior pole. A 5-year follow-up is planned.

Contents Vol. 43, 2010

Anatomy, Pathology and Cell Biology A. Prescott, Dundee Biochemistry, Molecular Biology and Molecular Genetics J. Graw, Neuherberg Clinical and Epidemiological Research M. Kojima, Kahoku Clinical Retina P. Wiedemann, Leipzig Cornea and Ocular Surface C. Marfurt, Gary, Ind. Glaucoma M. Coroneo, Sydney Immunology and Microbiology U. Pleyer, Berlin Lens and Cataract S. Varma, Baltimore, Md. Miscellaneous U. Pleyer, Berlin Neuro-Ophthalmology and Vision Sciences P. Aydin, Ankara Ocular Oncology M. Jager, Leiden Physiology, Pharmacology and Toxicology A. Wegener, Bonn Retina and Retinal Cell Biology M. Boulton, Gainesville, Fla. P. Wiedemann, Leipzig Editorial Board