Shigeru Honda

Genome-wide association study identifies two susceptibility loci for exudative age-related macular degeneration in the Japanese population

Age-related macular degeneration (AMD), the leading cause of irreversible blindness in the world, is a complex disease caused by multiple environmental and genetic risk factors. To identify genetic factors that modify the risk of exudative AMD in the Japanese population, we conducted a genome-wide association study and a replication study using a total of 1,536 individuals with exudative AMD and 18,894 controls. In addition to CFH (rs800292, P = 4.23 × 10−15) and ARMS2 (rs3750847, P = 8.67 × 10−29) loci, we identified two new susceptibility loci for exudative AMD: TNFRSF10A-LOC389641 on chromosome 8p21 (rs13278062, combined P = 1.03 × 10−12, odds ratio = 0.73) and REST-C4orf14-POLR2B-IGFBP7 on chromosome 4q12 (rs1713985, combined P = 2.34 × 10−8, odds ratio = 1.30). Fine mapping revealed that rs13278062, which is known to alter TNFRSF10A transcriptional activity, had the most significant association in 8p21 region. Our results provide new insights into the pathophysiology of exudative AMD.

Modulation of serotonin transporter activity by a protein kinase C activator and an inhibitor of type 1 and 2A serine/threonine phosphatases.

Abstract: We studied the effects of 12‐O‐tetradecanoylphorbol 13‐acetate (TPA), a protein kinase C (PKC) activator, and calyculin A (CLA), an inhibitor of type 1 and 2A serine/threonine phosphatases, on serotonin uptake by a human placenta choriocarcinoma cell line (BeWo) and COS‐7 cells expressing recombinant serotonin transporter (SET). In BeWo cells, treatment with TPA decreased imipramine‐sensitive serotonin uptake with a reduction in Vmax without affecting Km. CLA also decreased imipramine‐sensitive serotonin uptake in a manner similar to that of TPA. TPA and CLA also decreased the uptake activity of recombinant SET expressed in COS‐7 cells as seen in BeWo cells. These effects of TPA and CLA were reversed by staurosporine, a protein kinase inhibitor. To elucidate whether the inhibitory effects of TPA and CLA were due to direct phosphorylation of SET by PKC, site‐directed mutagenesis of five putative PKC phosphorylation sites in SET was performed. Serotonin uptake was also down‐regulated by TPA and CLA in all nine mutants, suggesting that these inhibitory modulation of SET activity did not act via direct phosphorylation of SET by PKC.

Preferable use of intravitreal bevacizumab as a pretreatment of vitrectomy for severe proliferative diabetic retinopathy

PurposeTo evaluate the safety and efficacy of intravitreal injection of bevacizumab advanced to vitrectomy for severe proliferative diabetic retinopathy.MethodsEight eyes of six patients (33–64 years old, all male patients) with severe proliferative diabetic retinopathy were investigated. An intravitreal injection of 1.25 mg bevacizumab was performed 3–30 days prior to planned vitrectomy.ResultsAll cases showed minimum bleeding during surgical dissection of fibrovascular membrane. Two cases receiving bevacizumab 7 days before the surgery showed strong fibrosis and adhesion of fibrovascular membrane, resulted in some surgical complications. The cases having intravitreal bevacizumab for shorter time did not show extensive fibrosis.ConclusionsThe pretreatment of bevacizumab is likely effective in the vitrectomy for severe PDR. The appropriate timing of vitrectomy after bevacizumab injection should be further evaluated.

SOD2 gene polymorphisms in neovascular age-related macular degeneration and polypoidal choroidal vasculopathy

PURPOSE To study and reveal genetic variation in the elastin gene (ELN) that may be associated with neovascular age-related macular degeneration (AMD) and/or polypoidal choroidal vasculopathy (PCV). Eyes with neovascular AMD and PCV exhibit substantially different structural alterations of the elastic layer in the Bruchs membrane. The hypothesis for the present study was that ELN polymorphisms may play a role in the development of neovascular AMD and PCV and that genetic differences in ELN between these two phenotypes may be a reason for the histopathologic differences. To test these hypotheses, ELN was screened for genetic variation in a Japanese case-control dataset. METHODS Two hundred eighty-five subjects were enrolled: 78 with neovascular AMD, 103 with PCV, and 104 control. We genotyped five tagged single nucleotide polymorphisms (SNPs) in ELN, and allele, genotype, and haplotype frequency distributions among neovascular AMD, PCV, and control subjects were compared by chi(2) tests. RESULTS A common ELN variant was significantly associated with susceptibility to PCV. The age- and sex-adjusted odds ratio was 7.56 for individuals homozygous for the risk allele compared with those carrying no more than one copy of the risk allele. Significantly different distributions were found in allele and haplotype frequencies between neovascular AMD and PCV in this region, but no particular ELN SNPs or haplotypes were significantly associated with neovascular AMD. CONCLUSIONS The findings implicate ELN as a susceptibility gene for PCV, and suggest that a different pathogenic process may be involved in the phenotypic expression of neovascular AMD and PCV.

Coding variant I62V in the complement factor H gene is strongly associated with polypoidal choroidal vasculopathy.

PURPOSE To investigate whether variants in the complement factor H (CFH) gene are associated with polypoidal choroidal vasculopathy (PCV). DESIGN Cross-sectional study. PARTICIPANTS A case-control group of 130 PCV subjects and 173 unrelated controls. METHODS We conducted an association analysis between CFH variants and PCV in a Japanese population, genotyping 12 tag single nucleotide polymorphisms (SNPs)-including rs3753394, rs800292 (I62V), and rs1061170 (Y402H)-that are highly representative of the common genetic variation in the CFH region. Genotyping was performed using TaqMan technology. MAIN OUTCOME MEASURES Allele and haplotype frequencies of the CFH variants. RESULTS A highly significant association with PCV was observed across the CFH region. The strongest association was observed at I62V (P = 1.7 x 10(-7)). Six other SNPs (rs3753394, rs6680396, rs1410996, rs2284664, rs1329428, and rs1065489) also showed significant association (10(-3) < P < 10(-6)). These associations became nonsignificant after accounting for rs800292 in a conditional logistic regression analysis. A significant omnibus haplotype association was detected in the entire CFH region (omnibus P = 1.6 x 10(-5) at 7 degrees of freedom). Conditional haplotype-based likelihood ratio tests revealed that the significant omnibus haplotype association disappeared when it was estimated conditional on I62V (omnibus P = 0.20, 6 degrees of freedom, post-I62V dependency), whereas the omnibus haplotype association remained significant when it was estimated conditional on any SNP other than I62V. These findings indicate that multiple observed effects were caused by linkage disequilibrium with I62V, and that this variant fully accounts for the association signals observed at the set of SNPs examined at this locus. CONCLUSIONS The present study provides evidence that the complement pathway plays a substantial role in the pathogenesis of PCV. The nonsynonymous variant I62V is a plausible candidate for a causal polymorphism leading to the development of PCV, given its potential for functional consequences on the CFH protein and our own statistical evidence. FINANCIAL DISCLOSURE(S) The authors have to proprietary or commercial interest in any materials discussed in this article.

Comparison of the Effect of Ranibizumab and Verteporfin for Polypoidal Choroidal Vasculopathy: 12-Month LAPTOP Study Results

PURPOSE To compare the effect of photodynamic therapy (PDT) and intravitreal ranibizumab in patients with polypoidal choroidal vasculopathy (PCV). DESIGN Randomized clinical trial. METHODS SETTING Multicenter. STUDY POPULATION Total of 93 patients with treatment-naïve PCV. INTERVENTION Patients were randomized to 2 arms. Patients in the PDT arm underwent a single session of PDT with verteporfin, and patients in the ranibizumab arm received 3 monthly ranibizumab injections at baseline. Additional treatment was performed as needed in each arm. MAIN OUTCOME MEASURES Primary outcome measurement was the proportion of patients gaining or losing more than 0.2 logarithm of minimal angle of resolution (logMAR) units from baseline. Mean change of logMAR and central retinal thickness (CRT) were also evaluated. RESULTS In the PDT arm (n = 47), 17.0% achieved visual acuity gain, 55.3% had no change, and 27.7% experienced visual acuity loss. The results were 30.4%, 60.9%, and 8.7%, respectively, in the ranibizumab arm (n = 46), significantly better than the PDT arm (P = .039). In the PDT arm, mean CRT improved (366.8 ± 113.6 μm to 289.1 ± 202.3 μm, P < .001), but logMAR was unchanged (0.57 ± 0.31 to 0.62 ± 0.40). The ranibizumab arm demonstrated improvement in both CRT (418.9 ± 168.6 μm to 311.2 ± 146.9 μm, P < .001) and logMAR (0.48 ± 0.27 to 0.39 ± 0.26, P = .003). Mean change of logMAR was also greater in the ranibizumab arm (P = .011). CONCLUSION Intravitreal injection of ranibizumab is more effective than PDT for treatment-naïve PCV.

Immunocytochemical localization of three subtypes of GABA transporter in rat retina

Cellular distributions of three subtypes of GABA transporter (GAT1, GAT2, GAT3) in the eye were examined using polyclonal antisera for each subtype. GAT1 was present in the inner plexiform layer and proximal part of the inner nuclear layer, while GAT3 was distributed throughout the entire sensory retina, being predominant in the distal part of the inner plexiform layer and in the outer plexiform layer. GAT2 immunoreactivity was seen in the retina, including the retinal pigment epithelium layer and nerve fiber layer, also in the ciliary body epithelium. Confocal scanning laser fluorescence microscopy disclosed that the GAT1 immunoreactivity consisted of a number of small deposits in the inner plexiform layer and that GAT1-immunoreactive dots encircle immunonegative neurons in the inner nuclear layer. GAT2 immunoreactivity was present in the fiber bundle of the optic nerve and in the retinal pigment epithelium within the retina. GAT3 immunoreactive cells had long processes running vertically throughout the sensory retina. GAT1 is suggested to be present mainly in the processes of amacrine cells and GAT3 to be distributed in Müller cells. We conclude that GAT1, GAT2 and GAT3 are expressed in different cells, that they are involved in distinct GABAergic transmission in the retina, and that GAT2 may be involved in non-neuronal functions in the eye.

Complement Factor H Y402H Variant and Risk of Age-Related Macular Degeneration in Asians: A Systematic Review and Meta-Analysis

PURPOSE To investigate whether the Y402H variant in the complement factor H gene is associated with age-related macular degeneration (AMD) in Asian populations. DESIGN Meta-analysis of previous publications. PARTICIPANTS Case-control groups of subjects with AMD and controls from 13 association studies. METHODS We performed a meta-analysis of the association between Y402H and AMD in Asian populations using data available from 13 case-control studies involving 3973 subjects. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using fixed- and random-effects models. The Q-statistic test was used to assess heterogeneity, and Eggers test was used to evaluate publication bias. Sensitivity analysis, cumulative meta-analysis, and meta-regression analysis were also performed. MAIN OUTCOME MEASURES Allele and genotype frequencies of the Y402H variant. RESULTS The Y402H variant showed a significant summary OR of 1.97 (95% CI, 1.54-2.52; P<0.001; allelic contrast model) per allele. Possession of at least 1 copy of the C allele increased the disease risk by 1.97-fold (95% CI, 1.63-2.39; P<0.001; dominant model) and accounted for 8.8% of the attributable risk of AMD in Asian populations. Sensitivity analysis indicated the robustness of our findings, and evidence of publication bias was not observed in our meta-analysis. Meta-regression analysis indicated no significant effect of baseline study characteristics on the summary effect size. Cumulative meta-analysis revealed that the summary ORs were stable and the 95% CIs narrowed with the accumulation of data over time. CONCLUSIONS Our analysis provides substantial evidence that the Y402H variant is significantly associated with AMD in Asian populations. Our results expand the number of confirmed AMD susceptibility loci for Asians populations, which provide a better understanding of the genetic architecture underlying disease susceptibility and may advance the potential for preclinical prediction in future genetic tests by a combined evaluation of inherited susceptibility with previously established loci.

Comparative Assessment of Photodynamic Therapy for Typical Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy: A Multicenter Study in Hyogo Prefecture, Japan

Purpose: We aimed to evaluate the effects of photodynamic therapy (PDT) on different phenotypes of age-related macular degenerations (AMD): typical AMD (tAMD) and polypoidal choroidal vasculopathy (PCV). Procedures: 246 eyes from 242 patients (tAMD: 139, PCV: 107 eyes) were recruited. Gender, age, best-corrected visual acuity (BCVA) before treatment, greatest linear dimension before treatment, lesion phenotype and PDT frequency were evaluated for predicting the BCVA at 12 months after PDT using stepwise multiple regression analyses. Additionally, 125 eyes with tAMD and 97 eyes with PCV followed up for more than 12 months after the final PDT were compared for the recurrence period. Results: In the stepwise analysis, a younger age, better pretreatment BCVA, lower PDT frequency, lesions with PCV and a smaller pretreatment greatest linear dimension were all significantly beneficial for a better BCVA at 12 months after PDT. PCV showed a significantly lower PDT frequency and greater improvement in the BCVA than tAMD. The recurrence period of PCV was significantly later than that of tAMD. Conclusions: The phenotype of AMD is significantly correlated with its prognosis after PDT. PCV showed a significantly better response to PDT in terms of BCVA improvement and effect durability.

Common Variants in the Complement Factor H Gene Confer Genetic Susceptibility to Central Serous Chorioretinopathy

PURPOSE To investigate whether complement factor H (CFH) gene DNA variants are associated with central serous chorioretinopathy (CSCR). DESIGN Cross-sectional study. PARTICIPANTS A case-control group of 140 CSCR subjects and 2 different control groups: 934 population-based controls and 335 hospital-based controls. METHODS Five single-nucleotide polymorphisms (SNPs) in CFH (rs3753394, rs800292, rs2284664, rs1329428, and rs106548) were evaluated for association with CSCR in 2 separate association analyses comparing CSCR subjects with 2 different control groups. Genotyping was performed using TaqMan technology (Applied Biosystems, Foster City, CA). MAIN OUTCOME MEASURES Allele and haplotype frequencies of the 5 variants in the CFH region. RESULTS Highly statistically significant associations with CSCR were found for the 5 SNPs. The strongest association was observed with rs1329428 (allelic P = 6.44×10(-6); odds ratio, 1.79; 95% confidence interval [CI], 1.39-2.31, cases vs. population-based controls), which accounted for 35.5% of the population-attributable fraction for CSCR. Consistent with the analysis, rs1329428 showed the strongest disease association (allelic P = 1.00×10(-5); odds ratio, 1.89; 95% CI, 1.42-2.50) in comparing cases with hospital-based controls. The second most strongly associated SNP, rs1065489, was correlated highly with the most strongly associated SNP, rs1329428 (r(2) = 0.77), and their effects could not be distinguished statistically from each other. A conditional logistic regression analysis revealed that the 2 highly correlated SNPs, rs1329428 and rs1065489, account for the association signals detected at the CFH locus. CONCLUSIONS We identified a novel association between CSCR and common CFH polymorphisms. Our findings support the involvement of CFH in the pathogenesis of CSCR; exploration of the role of CFH could yield important insights into the biological mechanisms underlying CSCR. Our identification of common CFH variants as susceptibility elements for CSCR will open new avenues for research, leading to a better understanding of CSCR pathogenesis and ultimately to the development of improved therapeutic approaches.