Low levels of plasma endothelin-1 in patients with retinitis pigmentosa

Hiroshi Ohguro1, Yukihiko Mashima2, Mitsuru Nakazawa31Department of Ophthalmology, Sapporo Medical University School of Medicine, 2Department of Ophthalmology, Keio University School of Medicine, 3Department of Ophthalmology, Hirosaki University School of Medicine, JapanPurpose: The aim of this study was to elucidate the role of endothelin-1 (ET-1) in the pathophysiology of retinitis pigmentosa (RP).Methods: Plasma ET-1 levels and ophthalmic features in 50 RP patients were compared with those in 20 healthy-eye control subjects. Plasma ET-1 concentrations were determined using a commercially available enzyme-linked immunosorbent assay kit.Results: Mean plasma ET-1 levels of RP patients (1.88 ± 0.56 pg/mL) were significantly lower than those of control subjects (2.30 ± 0.30 pg/mL, Mann-Whitney’s U test; P < 0.01). However, ET-1 concentrations varied markedly in each patient. Among RP patients, a significant correlation of ET-1 concentrations was not observed in terms of its hereditary forms or other clinical factors.Conclusion: ET-1 may be important in the pathogenesis of RP, and measurement of its plasma concentrations may also contribute to additional insights into the retinal hemodynamics of RP.Keywords: endothelin-1, retinitis pigmentosa, retinal hemodynamic

Vascular Adhesion Protein-1 Blockade Suppresses Ocular Inflammation After Retinal Laser Photocoagulation in Mice

PURPOSE. To investigate the effect of the vascular adhesion protein-1 (VAP-1) inhibitor RTU-1096 on retinal morphologic changes and ocular inflammation after retinal laser photocoagulation in mice. METHODS. C57BL/6JJcl mice were fed a diet containing RTU-1096, a specific inhibitor for VAP-1, or a control diet ad libitum for 7 days. Laser photocoagulation was performed on the peripheral retina of the animals. The semicarbazide sensitive amine oxidase (SSAO) activities in plasma and chorioretinal tissues were measured. Optical coherence tomography (OCT) images were acquired before and at 1, 3, and 7 days after laser photocoagulation, and thickness of the individual retinal layers was measured. Intravitreal leukocyte infiltration was assessed by histologic analysis. The expression level of intercellular adhesion molecule-1 (ICAM-1) in retinal tissues were examined by quantitative real-time PCR. RESULTS. One day after laser photocoagulation, the thickness of the outer nuclear layer (ONL) increased in the laser group compared with in the control group, and RTU-1096 administration abrogated the ONL thickening. Histologic analysis and OCT observation revealed that laser photocoagulation caused infiltration of inflammatory cells and the appearance of hyperreflective foci at the vitreoretinal surface, both of which were suppressed by RTU-1096 administration. In addition, systemic administration of RTU-1096 reduced upregulation of the leukocyte adhesion molecules ICAM-1 in the retina. CONCLUSIONS. The current data indicate that VAP-1/SSAO inhibition may be a potential therapeutic strategy for the prevention of macular edema secondary to scatter laser photocoagulation in patients with ischemic retinal diseases such as diabetic retinopathy

Blockade of vascular adhesion protein-1 attenuates choroidal neovascularization

Purpose: Vascular adhesion protein (VAP)-1 is an adhesion molecule elucidated as a mediator of the leukocyte recruitment cascade. The purpose of this study was to investigate the role of VAP-1 in ocular inflammatory neovascularization using a mouse laser-induced choroidal neovascularization (CNV) model. Methods: CNV was induced with 532 nm laser irradiation in C57BL/6 mice, and production of VAP-1 protein in the retinal pigment epithelium (RPE) choroid during CNV formation was examined. CNV animals were treated with the specific VAP-1 inhibitor U-V002 or vehicle solution, and the volume of CNV tissue was evaluated with volumetric measurements. Macrophage infiltration into the CNV lesions was evaluated using two different techniques, flatmount staining and real-time polymerase chain reaction (PCR) for F4/80. The protein levels of intercellular adhesion molecule (ICAM)-1, monocyte chemoattractant protein (MCP)-1, P-selectin, and vascular endothelial growth factor (VEGF) in the RPE-choroid were measured with enzyme-linked immunosorbent assay (ELISA). Results: VAP-1 inhibition significantly suppressed CNV formation in a dose-dependent manner and reduced macrophage infiltration into CNV lesions. Furthermore, VAP-1 blockade decreased the expression of ICAM-1 and MCP-1, both of which play a pivotal role in macrophage recruitment. Conclusions: Our data suggest VAP-1 has an important role during ocular inflammatory neovascularization through leukocyte recruitment. VAP-1 inhibition may be a novel and potent therapeutic strategy in treating CNV formation

Heterogeneity and uniqueness of ornithine aminotransferase mutations found in Japanese gyrate atrophy patients

Purpose. To identify mutations in ornithine aminotransferase (OAT) in seven Japanese families with gyrate atrophy (GA), an autosomal recessive chorioretinal degeneration of the eye caused by a generalized biochemical deficiency in OAT; mutations in the OAT gene have shown a high degree of molecular heterogeneity. Methods. DNA was prepared from patients' fibroblasts and analyzed by polymerase-chain-reaction amplification of the OAT gene sequence, denaturing gradient gel electrophoresis, and direct sequencing for identification of the mutations. Results. Eight different mutations were identified in seven unrelated Japanese GA patients with hyperornithinemia, confirming the high genetic heterogeneity of this disease. Five of these mutations were new, including one causing a pyridoxine-responsive disease, and all eight mutations have been found only in Japanese GA patients. Consistent with some similarity between the Japanese and Finnish populations in genetic isolation and homogeneity, there was a preponderance of homozygous mutations (five out of seven patients) as was previously reported for 16 Finnish GA pedigrees. Conclusions. The eight Japanese OAT mutations represent a group of heterogenous mutations unique to a specific population pool

SNPs and interaction analyses of noelin 2, myocilin, and optineurin genes in Japanese patients with open-angle glaucoma. Invest Ophthalmol Vis Sci 47

PURPOSE. To evaluate the noelin 2 gene as a disease-causing factor for open-angle glaucoma (OAG) and the interactions between the noelin 2 (OLFM2), optineurin (OPTN), and myocilin (MYOC) genes. METHODS. OLFM2 was analyzed in 770 Japanese subjects including 215 patients with elevated intraocular pressure (IOP), 277 with normal IOP, 38 with juvenile open-angle glaucoma, and 240 control subjects. Two single-nucleotide polymorphisms (SNPs) in OPTN (c.412G3 A and c.603T3 A) and one SNP in MYOC (c.227G3 A) were examined. Single genes were investigated by univariate analysis and the gene-gene interactions by logistic regression analysis. Associations between genotypes and clinical characteristics at the time of diagnosis were examined. RESULTS. In OLFM2, 12 sequence variants were identified in 770 Japanese subjects. Arg144Gln (exon 4) was identified in two (0.3%) of the patients and in none of the control subjects. Combinations of OLFM2/317A and OPTN/412A or OLFM2/ 1281T and OPTN/412A were associated with patients with elevated IOP (P ϭ 0.018 or P ϭ 0.012, respectively). The combination of OLFM2/317G and OPTN/603A was significantly associated with elevated IOP (P ϭ 0.018). No significant association was detected between SNPs in OLFM2 and in MYOC. Patients with normal IOP and with OLFM2/ 678AϩOPTN/412G or OLFM2/1281CϩOPTN/412G had significantly worse visual field scores (P ϭ 0.022 or 0.030, respectively). CONCLUSIONS. The Arg144Gln mutation in OLFM2 is a possible disease-causing mutation in Japanese patients with OAG. Common polymorphisms in OLFM2 and OPTN may interactively contribute to the development of OAG, indicating a polygenic etiology. (Invest Ophthalmol Vis Sci. 2006;47:5368 -5375) DOI:10.1167/iovs.06-0196 G laucoma is the second leading cause of blindness worldwide, and is estimated to affect more than 60 million people. Open-angle glaucoma (OAG), the most common form, is present in almost 2% of the world's population older than 40 years. 1 Glaucoma includes a group of conditions that is characterized by progressive optic neuropathy with visual field changes corresponding to the damage of the retinal nerve fibers. These changes are usually associated with an elevation of intraocular pressure (IOP). Elevated IOP is generally accepted to be a major risk factor for glaucomatous changes. Genetic factors also play a major role in the etiology of OAG. 3 The first gene to be characterized was the trabecular meshwork-inducible glucocorticoid response (TIGR) gene on 1q. 14 Most of the mutations in MYOC are located in the olfactomedin domain. Olfactomedin is a secreted polymeric glycoprotein of unknown function with an evolutionarily conserved C-terminal motif. 5 Mukhopadhyay et al. 19 identified myocilin-related human proteins having a conserved olfactomedin domain using bioinformatics approaches and examined the expression patterns in the eye. Myocilin-related proteins with homology to human myocilin were selected by BLASTp

Visual prognosis better in eyes with less severe reduction of visual acuity one year after onset of Leber hereditary optic neuropathy caused by the 11,778 mutation

Abstract Background Patients with Leber hereditary optic neuropathy (LHON) have a progressive decrease of their visual acuity which can deteriorate to <0.1. Some patients can have a partial recovery of their vision in one or both eyes. One prognostic factor associated with a recovery of vision is an early-age onset. The purpose of this study was to determine other clinical factors that are predictive of a good visual recovery. Methods Sixty-one Japanese LHON patients, with the 11,778 mutation and a mean age of 23.1 ± 12.1 years at the onset, were studied. All patients were initially examined at an acute stage of LHON and were followed for 3 to 10 years. At 1 year after the onset, the lowest visual acuity was <0.1 in all eyes. We studied the following parameters of patients with/without a final visual acuity of ≥ 0.2: sex; heavy consumption of cigarettes and alcohol; taking idebenone; mean age at onset; mean lowest visual acuity; and distribution of the lowest and the final visual acuity. Results Fifteen (24.6%) of the 61 patients or 25 (20.5%) of the 122 eyes had a recovery of their visual acuity to ≥ 0.2. The mean age at onset of these 15 patients with visual recovery to ≥ 0.2 was 17.5 ± 7.7 years, and that of the 46 patients without visual recovery to ≥ 0.2 was 25.0 ± 12.8 years (P = 0.02, Mann-Whitney U test). The mean lowest visual acuity of the 25 eyes with visual recovery ≥ 0.2 was 0.04, and that of the 97 eyes without visual recovery to ≥ 0.2 was 0.015 (P < 0.001, Mann-Whitney U test). Fifty percent (15/30) of the eyes whose lowest visual acuity was ≥ 0.04 during 1 year after the onset had a visual recovery to ≥ 0.2, while 11% (10/92) of the eyes whose the lowest visual acuity was ≤ 0.03 had a visual recovery to ≥ 0.2 (P < 0.001, χ 2 test). There were no significant differences in the other clinical factors. Conclusion A final visual acuity of ≥ 0.2 was associated with a less severe reduction of the visual acuity at 1 year after the onset. Our findings can be used to predict the visual prognosis in LHON patients

Genotype-phenotype correlation of a pyridoxine-responsive form of gyrate atrophy

Two clinical subtypes of gyrate atrophy (GA) have been defined based on in vivo or in vitro evidence of response to vitamin B6 (pyridoxine), which is the cofactor of the enzyme ornithine aminotransferase (OAT) shown to be defective in GA. We identified the E318K mutation in the OAT gene, heterozygously in three patients and homozygously in one patient, all of whom were vitamin B6-responsive by previous in vivo and in vitro studies. Dose-dependent effects of the E318K mutation were observed in the homo- and heterozygotes in the OAT activity, increase of OAT activity in the presence of pyridoxal phosphate, and apparent Km for pyridoxal phosphate. The highest residual level of OAT activity and mildness of clinical disease correlated directly with the dose of the mutant E318K allele present in the patient