Publications by authors named "Ryutaro Akiba"

: This study aimed to determine whether there is a significant change in eyeball curvature in eyes with retinitis pigmentosa (RP). : The medical records of 35 eyes of 18 patients with RP and age- and axial-length-matched controls were reviewed. The curvature of the posterior pole was determined by approximating a second-order polynomial equation based on the optical coherence tomography (OCT) images.

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Purpose: Retinitis pigmentosa represents a leading cause of blindness in developed countries, yet effective treatments for the disease remain unestablished. Previous studies have demonstrated the potential of stem cell-derived retinal organoid (SC-RO) sheet transplantation to form host-graft synapses and to improve light responsiveness in animal models of retinal degeneration. However, the detailed microstructures of these de novo synapses and their functional contribution have not been well elucidated.

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Macular hole (MH) is a retinal break involving the fovea that causes impaired vision. Although advances in vitreoretinal surgical techniques achieve >90% MH closure rate, refractory cases still exist. For such cases, autologous retinal transplantation is an optional therapy showing good anatomic success, but visual improvement is limited and peripheral visual field defects are inevitable after graft harvesting.

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The retinal fovea in human and nonhuman primates is essential for high acuity and color vision. Within the fovea lies specialized circuitry in which signals from a single cone photoreceptor are largely conveyed to one ON and one OFF type midget bipolar cell (MBC), which in turn connect to a single ON or OFF midget ganglion cell (MGC), respectively. Restoring foveal vision requires not only photoreceptor replacement but also appropriate reconnection with surviving ON and OFF MBCs and MGCs.

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The discovery of induced Pluripotent Stem) (iPS) cells has instigated innovation in various fields, including ophthalmology. Cell therapy has shown tremendous progress in translational research on retinal diseases, including the first-in-human transplantation of autologous iPS cell-derived retinal pigment epithelium (RPE) cells for patients with age-related macular degeneration (AMD). Cell therapy for retinitis pigmentosa (RP) has also been developed.

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ESC/iPSC-retinal sheet transplantation, which supplies photoreceptors as well as other retinal cells, has been shown to be able to restore visual function in mice with end-stage retinal degeneration. Here, by introducing a novel type of genetically engineered mouse ESC/iPSC-retinal sheet with reduced numbers of secondary retinal neurons but intact photoreceptor cell layer structure, we reinforced the evidence that ESC/iPSC-retinal sheet transplantation can establish synaptic connections with the host, restore light responsiveness, and reduce aberrant retinal ganglion cell spiking in mice. Furthermore, we show that genetically engineered grafts can substantially improve the outcome of the treatment by improving neural integration.

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Retinitis pigmentosa (RP) is a group of hereditary diseases that involve loss of photoreceptors. There has been no established treatment for RP, and it is now the 2 leading cause of blindness in Japan. Previous clinical researches using human fetal retina transplantation suggested some functional recovery in vision, but it did not become a standard therapy because of ethical concerns for using fetus tissues.

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Quantitative and qualitative evaluation of synapses is crucial to understand neural connectivity. This is particularly relevant now, in view of the recent advances in regenerative biology and medicine. There is an urgent need to evaluate synapses to access the extent and functionality of reconstructed neural network.

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Purpose: Retinitis Pigmentosa (RP) is the most common form of inherited retinal dystrophy caused by different genetic variants. More than 60 causative genes have been identified to date. The establishment of cost-effective molecular diagnostic tests with high sensitivity and specificity can be beneficial for patients and clinicians.

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Background: Previous studies of neuromyelitis optica spectrum disorder (NMOSD) using spectral domain optical coherence tomography (SD-OCT) showed that the outer nuclear layer (ONL) in eyes without a history of optic neuritis (ON) was thinner than that of healthy controls. It remains unclear whether the ONL thinning is caused by a direct attack on the retina by an autoantibody or a retrograde degeneration.

Objective: To determine the mechanisms involved in the retinal damage in eyes with NMOSD without ON.

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Background: Both neuromyelitis optica spectrum disorder (NMOsd) and multiple sclerosis (MS) patients experience optic neuritis (ON) attacks characterized by rapidly reduced best-correct visual acuity (BCVA) and slow recovery. Prognosis and effects of recurrence on recovery may differ between disorders but remain unclear.

Objective: To compare ON severity, time and degree of recovery and effects of previous ON between NMOsd and MS patients.

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Neuromyelitis optica spectrum disorder (NMO-SD) is an autoimmune inflammatory disorder associated with the anti-aquaporin-4 (AQP4) antibody. Over 90% of NMO-SD patients have poor prognosis, and pregnancy is a disease-worsening factor. The authors report the findings in a case of NMO-SD that recovered spontaneously during pregnancy.

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