Sho Kabasawa

Phenotype and Genotype Characteristics of Age-related Macular Degeneration in a Japanese Population

PURPOSE To describe phenotype and genotype characteristics of age-related macular degeneration (AMD) in Japanese patients. DESIGN A case-control study. PARTICIPANTS A total of 550 case-control samples composed of 408 consecutive AMD cases and 142 controls. METHODS Clinical information assessing age, gender, affected eyes, fundus features, and fluorescein/indocyanine green angiograms were systematically evaluated. Four single nucleotide polymorphisms (SNPs; rs800292, rs1061170, rs1410996, rs2274700) in the complement factor H (CFH) gene, 1 SNP (rs11200638) in the high-temperature requirement factor A1 (HTRA1) gene, 3 SNPs (rs699947, rs1570360, rs2010963) in the vascular endothelial growth factor (VEGF) gene, and 4 SNPs (rs12150053, rs12948385, rs9913583, rs1136287) in the pigment epithelium-derived factor (PEDF) gene were assessed using TaqMan technology. MAIN OUTCOME MEASURES The clinical phenotype information and genotypes of CFH, HTRA1, VEGF, and PEDF polymorphisms. RESULTS Of Japanese patients with neovascular AMD (nAMD), 219 (58.7%) had typical nAMD and 154 (41.3%) had polypoidal choroidal vasculopathy (PCV). The frequency of bilateral exudative involvement was similar between typical nAMD (15.5%) and PCV (13.6%) (P = 0.613). Significant soft drusen were observed in the fellow eyes of 88 (47.6%) of 185 patients with unilateral typical nAMD and in 25 (18.8%) of 133 patients with unilateral PCV (P = 1.24x10(-7)). A serous pigment epithelium detachment was seen in 55 (25.1%) of 219 patients with typical nAMD and in 64 (41.6%) of 154 patients with PCV. A significant association was noted in CFH-rs800292, CFH-rs1410996, CFH-rs2274700, and HTRA1-rs11200638 with AMD development (P = 2.36x10(-5), 7.18x10(-5), 7.18x10(-5), 2.70x10(-7), respectively; population attributable risk = 57.3%, 57.8%, 57.8%, and 58.9%, respectively). We estimated the highest-risk group to have an approximately 70-fold greater risk of nAMD compared with the lowest-risk group when analyzing a combination of 4 SNPs in the CFH and HTRA1 genes. CONCLUSIONS The Japanese AMD phenotype is characterized by a higher frequency of PCV, male predominance, and lower frequency of bilateral presentation compared with Caucasian AMD. Genotype analyses demonstrate a significant population attributable risk for SNPs in the CFH and HTRA1 genes and demonstrate joint effects for both genes. Gene variants in both CFH and HTRA1 contribute significantly to the AMD phenotype in a Japanese population.

Complement Factor H and High-Temperature Requirement A-1 Genotypes and Treatment Response of Age-related Macular Degeneration

PURPOSE To determine whether there is an association between complement factor H (CFH), high-temperature requirement A-1 (HTRA1), vascular endothelial growth factor (VEGF), and pigment epithelium-derived factor (PEDF) genotypes and response to treatment with photodynamic therapy (PDT) for age-related macular degeneration (AMD) in a Japanese population. DESIGN Prospective, case-control study. PARTICIPANTS One hundred ten patients with exudative AMD treated by verteporfin PDT were recruited prospectively at the Department of Ophthalmology, Saitama Medical University Hospital, Saitama, Japan. METHODS The patients were genotyped for 4 single nucleotide polymorphisms (SNPs; rs800292, rs1061170, rs1410996, rs2274700) in the CFH gene, a rs11200638-SNP in the HTRA1 gene, 3 SNPs (rs699947, rs1570360, rs2010963) in the VEGF gene, and 4 SNPs (rs12150053, rs12948385, rs9913583, rs1136287) in the PEDF gene using a TaqMan assay. MAIN OUTCOME MEASURES The treatment outcomes and genotypes of CFH, HTRA1, VEGF, and PEDF polymorphisms. RESULTS Best-corrected visual acuity 1 year after PDT was significantly increased in patients with the HTRA1-rs11200638 GG genotype as compared with patients with the GA or AA genotypes (P = 2.9 × 10⁻², 7.0 × 10⁻⁴, respectively). The rate of recurrence in the 12-month period after PDT was also associated with HTRA1-rs11200638 genotype (P = 3.12 × 10⁻²). Patients with the AA genotype of HTRA1-rs11200638 had an approximately 6-fold greater risk of the recurrence than patients with the GG genotype (P = 5.58 × 10⁻³). Significant differences were demonstrated in the mean time interval from the initial treatment to the time of recurrence for the genotypes of CFH-rs1410996/-rs2274700 (P = 8.50 × 10⁻³). CONCLUSIONS The HTRA1-rs11200638 and CFH-rs1410996/-rs2274700 variants were associated with response to PDT in this study population. These variants may be used for genetic biomarkers to estimate visual outcomes and recurrences in the response to PDT with significant predictive power.

Associations of cigarette smoking but not serum fatty acids with age-related macular degeneration in a Japanese population.

PURPOSE To assess modifiable environmental risk factors and protective factors for age-related macular degeneration (AMD) in a native Japanese population. DESIGN A case-control study. PARTICIPANTS We included 422 case-control samples composed of 279 consecutive AMD cases and 143 controls. METHODS Information regarding systemic conditions and lifestyle were documented in each subject by standardized questionnaire including age, gender, smoking history, body mass index (BMI), and history of cardiovascular disease, hypertension, and diabetes. Serum fatty acids profiles were analyzed by gas chromatography performed on blood samples taken from each study participant. Logistic regression and multiple comparison analyses were utilized in this study. MAIN OUTCOME MEASURES Population-specific information assessing systemic conditions, lifestyle, and serum fatty acid profiles. RESULTS Among environmental factors analyzed cigarette smoking showed the most significant association with development of all AMD (P<0.00001; odds ratio [OR], 4.06; 95% confidence interval [CI], 2.22-7.43), typical neovascular AMD (P<0.0001, OR, 4.59; 95% CI, 2.29-9.18), and polypoidal choroidal vasculopathy (P<0.001; OR, 4.87; 95% CI, 1.96-12.1). Hypertension and BMI showed a mild association with AMD. Although male prevalence was significantly higher in all case groups than in controls with conventional Scheffe correction, there was no association of gender with AMD development when logistic regression analysis was used to adjust for cigarette smoking. There was no difference in fatty acid profiles, except for a mild association of eicosapentaenoic acid concentration in the all AMD group. CONCLUSIONS In the Japanese population studied, cigarette smoking influenced the risk of AMD but fractionated serum fatty acid levels did not. Although prior reports indicate a male predominance in Japanese patients with AMD, this study demonstrates that cigarette smoking accounts for this confounding bias. In addition, our population-specific data do not demonstrate significant differences in serum fatty acid composition, including ω-3 and ω-6 long chain polyunsaturated fatty acids, in Japanese patients with and without AMD. These results are consistent with the high proportion of smokers in aged Japanese men and the high fish oil intake in this population. FINANCIAL DISCLOSURE(S) The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Photodynamic therapy of experimental choroidal neovascularization with a hydrophilic photosensitizer: mono-L-aspartyl chlorin e6.

Purpose To demonstrate the selective localization of the hydrophilic photosensitizer mono-L-aspartyl chlorin e6 (NPe6) in experimental choroidal neovascularization in nonhuman primate eyes. Methods Sixty-seven experimental choroidal neovascular lesions (CNV) were created in the fundi of Macaca monkeys using the modified Ryan‘s model and documented by fluorescein and indocyanine green angiography. To determine the biodistribution of NPe6 and the optimal timing of laser irradiation after dye administration, NPe6 angiography and fluorescence microscopy with NPe6 were performed. Photodynamic therapy (PDT) was performed at various dye doses (0.5–10.0 mg/kg) and laser fluences (7.5–225.0 J/cm2) on the CNV and on 10 areas of normal retina and choroid. Treatment outcomes were assessed by fluorescein and indocyanine green angiography and confirmed by light and electron microscopy. Results NPe6 fluorescence microscopy demonstrated intense fluorescence of CNV and retinal pigment epithelial cells. Choroidal vessel walls and outer retina adjacent to CNV fluoresced moderately; retinal vessel walls and microcapillaries had trace fluorescence. The fluorescence of CNV lesions on fluorescein angiography became stronger than that of retinal vessels 20–60 minutes after dye injection. Choroidal neovascular lesion closure was achieved with NPe6 PDT without significant damage to the sensory retina. Histology demonstrated necrosis of CNV endothelial cells with minimal damage to surrounding tissues. Conclusions NPe6 PDT selectively localizes to experimental CNV in nonhuman primates, resulting in occlusion of CNV with sparing of the neurosensory retina.

A prospective multicenter study on genome wide associations to ranibizumab treatment outcome for age-related macular degeneration

We conducted a genome-wide association study (GWAS) on the outcome of anti-VEGF treatment for exudative age-related macular degeneration (AMD) in a prospective cohort. Four hundred and sixty-one treatment-naïve AMD patients were recruited at 13 clinical centers and all patients were treated with 3 monthly injections of ranibizumab followed by pro re nata regimen treatment for one year. Genomic DNA was collected from all patients for a 2-stage GWAS on achieving dry macula after the initial treatment, the requirement for an additional treatment, and visual acuity changes during the 12-month observation period. In addition, we evaluated 9 single-nucleotide polymorphisms (SNPs) in 8 previously reported AMD-related genes for their associations with treatment outcome. The discovery stage with 256 patients evaluated 8,480,849 SNPs, but no SNPs showed genome-wide level significance in association with treatment outcomes. Although SNPs with P-values of <5 × 10−6 were evaluated in replication samples of 205 patients, no SNP was significantly associated with treatment outcomes. Among AMD-susceptibility genes, rs10490924 in ARMS2/HTRA1 was significantly associated with additional treatment requirement in the discovery stage (P = 0.0023), and pooled analysis with the replication stage further confirmed this association (P = 0.0013). ARMS2/HTRA1 polymorphism might be able to predict the frequency of injection after initial ranibizumab treatment.