Macular Degeneration: Mashima Y

Noda K, She H, Nakazawa T, Hisatomi T, Nakao S, Almulki L, Zandi S, Miyahara S, Ito Y, Thomas KL, Garland RC, Miller JW, Gragoudas ES, Mashima Y, Hafezi-Moghadam A. · Angiogenesis Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA. · FASEB J. · Pubmed #18436961 links to  free full text

Abstract: Vascular adhesion protein-1 (VAP-1) is an endothelial cell adhesion molecule involved in leukocyte recruitment. Leukocytes and, in particular, macrophages play an important role in the development of choroidal neovascularization (CNV), an integral component of age-related macular degeneration (AMD). Previously, we showed a role for VAP-1 in ocular inflammation. Here, we investigate the expression of VAP-1 in the choroid and its role in CNV development. VAP-1 was expressed in the choroid, exclusively in the vessels, and colocalized in the vessels of the CNV lesions. VAP-1 blockade with a novel and specific inhibitor significantly decreased CNV size, fluorescent angiographic leakage, and the accumulation of macrophages in the CNV lesions. Furthermore, VAP-1 blockade significantly reduced the expression of inflammation-associated molecules such as tumor necrosis factor (TNF) -alpha, monocyte chemoattractant protein (MCP) -1, and intercellular adhesion molecule (ICAM) -1. This work provides evidence for an important role of VAP-1 in the recruitment of macrophages to CNV lesions, establishing a novel link between VAP-1 and angiogenesis. Inhibition of VAP-1 may become a new therapeutic strategy in the treatment of AMD.

Noda K, Miyahara S, Nakazawa T, Almulki L, Nakao S, Hisatomi T, She H, Thomas KL, Garland RC, Miller JW, Gragoudas ES, Kawai Y, Mashima Y, Hafezi-Moghadam A. · Department of Ophthalmology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts, USA. · FASEB J. · Pubmed #18032635 links to  free full text

Abstract: Inflammatory leukocyte accumulation is a common feature of major ocular diseases, such as uveitis, diabetic retinopathy, and age-related macular degeneration. Vascular adhesion protein-1 (VAP-1), a cell surface and soluble molecule that possesses semicarbazide-sensitive amine oxidase (SSAO) activity, is involved in leukocyte recruitment. However, the expression of VAP-1 in the eye and its contribution to ocular inflammation are unknown. Here, we investigated the role of VAP-1 in an established model of ocular inflammation, the endotoxin-induced uveitis (EIU), using a novel and specific inhibitor. Our inhibitor has a half-maximal inhibitory concentration (IC(50)) of 0.007 microM against human and 0.008 microM against rat SSAO, while its IC(50) against the functionally related monoamine oxidase (MAO) -A and MAO-B is >10 microM. In the retina, VAP-1 was exclusively expressed in the vasculature, and its expression level was elevated during EIU. VAP-1 inhibition in EIU animals significantly suppressed leukocyte recruitment to the anterior chamber, vitreous, and retina, as well as retinal endothelial P-selectin expression. Our data suggest an important role for VAP-1 in the recruitment of leukocytes to the immune-privileged ocular tissues during acute inflammation. VAP-1 inhibition may become a novel strategy in the treatment of ocular inflammatory diseases.

Shinoda K, Ishida S, Oguchi Y, Mashima Y. · Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan. · Ophthalmic Genet. · Pubmed #11035549 No free full text.

Abstract: To characterize the clinical features associated with XLRS1 gene mutations in Japanese patients with X-linked juvenile retinoschisis (xlRS), we evaluated the following data on 14 Japanese males from 13 unrelated families with XLRS1 mutations: age and symptoms at first visit to an ophthalmologist and ophthalmologic findings including visual acuity, refractive errors, fundoscopic appearance, and results of electroretinography (ERG) and electro-oculography (EOG). Each clinical finding was reviewed when the patients were between six and eight years of age. The best-corrected visual acuity in 12 patients (24 eyes) between the ages 6 and 8 years ranged from 1.0 to no light perception. Macular abnormalities were present in all cases. Peripheral retinoschisis was present in 14 of 26 eyes (53.8%). In the 21 eyes for which a single-flash ERG had been recorded, b-wave amplitude was reduced in 17 eyes. The EOG showed a low Arden ratio in three of the 13 eyes in the seven patients evaluated. No clear relationship was observed between the clinical features and the existing mutations. Three of four patients with a visual acuity less than 0.1 had retinal detachment or severe macular lesion that had occurred before the age of four years. Two patients harbored deletions of exon 1 or of the boundary region between exon 3 and intron 3, and one patient harbored R182C in exon 6. The present study shows a heterogeneity of mutations in the XLRS1 gene and phenotypic variations in 14 Japanese patients with xlRS.

Mashima Y, Saga M, Hiida Y, Imamura Y, Kudoh J, Shimizu N. · Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan. · Am J Ophthalmol. · Pubmed #11020419 No free full text.

Abstract: PURPOSE: To report the identification of a novel mutation of the RP2 gene in two Japanese brothers with X-linked retinitis pigmentosa of a differing clinical severity. The mother was a carrier of both retinitis pigmentosa and optic atrophy. METHODS: The older brother had a severe form of retinitis pigmentosa associated with macular degeneration and total optic atrophy, whereas the younger brother presented typical X-linked retinitis pigmentosa. RESULTS: Each patient exhibited a novel 2-bp insertion at codon 278 in exon 3 of the RP2 gene as well as a 11778 mutation in mitochondrial DNA. This suggests that the older brother may have developed Leber hereditary optic neuropathy as well as retinitis pigmentosa. CONCLUSION: Molecular testing confirmed the clinical diagnosis in each case. However, such testing did not explain the differences in the severity of the ophthalmoscopic findings between the two brothers.

Shinoda K, Mashima Y, Ishida S, Oguchi Y. · Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan. · Ophthalmic Genet. · Pubmed #10454824 No free full text.

Abstract: X-linked juvenile retinoschisis is a form of vitreoretinal dystrophy that is characterized by foveal and peripheral splitting of the retinal nerve fiber layer. Pathognomonic of this disorder is a microcystic radiate appearance in the fovea. We encountered a 10 year-old, mildly retarded, Japanese boy, who exhibited a widely extended macular retinoschisis bilaterally. A break in the inner layer of the left eye mimicked a lamellar macular hole, which is a rare manifestation of the disease. Peripheral retinoschisis was absent. Only a few reports have described marked bilateral macular retinoschisis that involved entire posterior pole, while various other macular findings have been reported. This patient with a severe form of retinoschisis was found to harbor the deletion of 33 base pairs, including the boundary region of exon 3 and intron 3 in the XLRS1 gene.