Sotaro Ooto

Wnt Signaling Promotes Regeneration in the Retina of Adult Mammals

Regeneration in the mammalian CNS is severely limited. Unlike in the chick, current models hold that retinal neurons are never regenerated. Previously we demonstrated that, in the adult mammalian retina, Müller glia dedifferentiate and produce retinal cells, including photoreceptors, after acute neurotoxic injury in vivo. However, the number of newly generated retinal neurons is very limited. Here we demonstrate that Wnt (wingless-type MMTV integration site family)/β-catenin signaling promotes proliferation of Müller glia-derived retinal progenitors and neural regeneration after damage or during degeneration. Wnt3a treatment increases proliferation of dedifferentiated Müller glia >20-fold in the photoreceptor-damaged retina. Supplementation with retinoic acid or valproic acid induces differentiation of these cells primarily into Crx (cone rod homeobox)-positive and rhodopsin-positive photoreceptors. Notably, injury induces nuclear accumulation of β-catenin, cyclin D1 upregulation, and Wnt/β-catenin reporter activity. Activation of Wnt signaling by glycogen synthase kinase-3β inhibitors promotes retinal regeneration, and, conversely, inhibition of the signaling attenuates regeneration. This Wnt3a-mediated regeneration of retinal cells also occurs in rd mice, a model of retinal degeneration. These results provide evidence that Wnt/β-catenin signaling contributes to CNS regeneration in the adult mammal.

Macular Choroidal Thickness and Volume in Normal Subjects Measured by Swept-Source Optical Coherence Tomography

PURPOSE To study the choroidal thickness in healthy subjects by swept-source optical coherence tomography (SS-OCT) at longer wavelength. METHODS The macular area of 31 eyes (31 healthy volunteers) was studied with an SS-OCT prototype system, which uses a tunable laser as a light source operated at 100,000 Hz A scan repetition rate in the 1-μm wavelength region. Three-dimensional volumetric measurement comprised of 512 × 128 A scans was acquired in 0.8 second. From a series of OCT images, a chroidal thickness map of the macular area was created by manual segmentation. To evaluate interoperator reproducibility, the choroidal thickness in each section from 10 subjects was determined independently by two observers. RESULTS SS-OCT at the 1-μm wavelength region allowed visualization of the fine structure of the choroid as well as that of the retina. Mean choroidal thickness and volume in the macula area were, respectively, 191.5 ± 74.2 μm and 5.411 ± 2.097 mm(3). The mean choroidal thickness of the outer nasal area was significantly thinner than that of all other areas (P < 0.05). The measurements by the two independent observers were significantly identical; the intraclass correlation coefficient in mean choroidal thickness was between 0.945 and 0.980 in each area. The macular choroidal thickness was significantly correlated with axial length after adjustment for age (P < 0.001), and with age after adjustment for axial length (P < 0.001). CONCLUSIONS SS-OCT system at 1 μm provides macular choroidal thickness maps and allows one to evaluate the choroidal thickness more accurately.

Effects of Age, Sex, and Axial Length on the Three-Dimensional Profile of Normal Macular Layer Structures

PURPOSE To identify sex-related differences and age-related changes in individual retinal layer thicknesses in a population of healthy eyes across the lifespan, using spectral domain optical coherence tomography (SD-OCT). METHODS In seven institutes in Japan, mean thicknesses of the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor inner segment (IS), and photoreceptor outer segment (OS) were measured using SD-OCT with a new automated segmentation protocol in 256 healthy subjects. RESULTS Interoperator coefficients of variability for measurements of each layer ranged from 0.012 to 0.038. The RNFL, GCL, IPL, and INL were thinnest in the foveal area, whereas the OPL+ONL and OS were thickest in this area. Mean thicknesses of the INL and the OPL+ONL were significantly greater in men (P = 0.002 and 0.001, respectively). However, mean RNFL thickness was greater in women (P = 0.006). Thicknesses of the RNFL, GCL, IPL, INL, and IS correlated negatively with age. Thickness of the OPL+ONL was not correlated with age, and thickness of the OS correlated positively with age. Inner retinal (RNFL+GCL+IPL) thickness over the whole macula correlated negatively with age (P < 0.001), but outer retinal (OPL+ONL+IS+OS) thickness did not. Thicknesses of layers did not correlate with axial length. CONCLUSIONS Macular layer thicknesses measured on SD-OCT images in healthy eyes showed significant variations by sex and age. These findings should inform macular layer thickness analyses in SD-OCT studies of retinal diseases and glaucoma.

Assessment of macular choroidal thickness by optical coherence tomography and angiographic changes in central serous chorioretinopathy.

OBJECTIVE To investigate the relationship between macular choroidal thickness measured by high-penetrating swept-source optical coherence tomography (SS-OCT) and angiographic findings in central serous chorioretinopathy (CSC). DESIGN Prospective cross-sectional case series. PARTICIPANTS AND CONTROLS Thirty-four patients with CSC (44 eyes) and 17 volunteer subjects (17 normal eyes). METHODS All subjects underwent a comprehensive ophthalmologic and SS-OCT prototype examination. All patients with CSC also underwent simultaneous fluorescein angiography (FA) and indocyanine green angiography (IA). Mean regional choroidal thickness measurements on the Early Treatment Diabetic Retinopathy Study (ETDRS) layout and squared sector grids were obtained by 3-dimensional raster scanning using SS-OCT. MAIN OUTCOME MEASURES Macular choroidal thickness and angiographic abnormalities. RESULTS Mean whole macular choroidal thickness in eyes with CSC (total, 329.3±83.0 μm; classic CSC, 326.9±83.1 μm; chronic CSC, 325.4±93.3 μm; and multifocal posterior pigment epitheliopathy, 359.0±15.5 μm) was greater than that in normal eyes (233.0±67.0 μm) (P < 0.001). In unilateral cases, mean whole macular choroidal thickness was greater in eyes with unilateral CSC than in unaffected fellow eyes (P=0.021). There was no significant difference in choroidal thickness between active eyes and resolved eyes in any of the ETDRS sectors. Mean choroidal thickness was greater in areas with leakage on FA than in areas without leakage (P=0.001). Mean choroidal thickness was greater in areas with choroidal vascular hyperpermeability and in areas with punctate hyperfluorescent spots on IA than in unaffected areas (P<0.001 for both). CONCLUSIONS Increased choroidal thickness was observed in the whole macular area of eyes with any of the CSC subtypes. Choroidal thickness was related to leakage from the retinal pigment epithelium, choroidal vascular hyperpermeability, and punctate hyperfluorescent lesions. These findings provide evidence that CSC may be caused by focally increased hydrostatic pressure in the choroid.

Choroidal Thickness, Vascular Hyperpermeability, and Complement Factor H in Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy

PURPOSE To investigate the relationship between subfoveal choroidal thickness, choroidal vascular hyperpermeability, and complement factor H (CFH) gene polymorphism in typical age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV). METHODS Fifty-eight patients with typical AMD and 63 patients with PCV underwent fluorescein angiography, indocyanine green angiography (IA), and spectral-domain optical coherence tomography (OCT) using enhanced depth imaging (EDI). Subfoveal choroidal thickness was measured using EDI-OCT images, and choroidal hyperpermeability was evaluated using late-phase IA images. The major AMD-associated single-nucleotide polymorphisms were genotyped in 86 patients. RESULTS Mean subfoveal choroidal thickness was significantly lower in eyes with typical AMD than that in eyes with PCV (P = 0.025). Subfoveal choroidal thickness was greater in eyes with choroidal hyperpermeability than that in eyes without it in typical AMD (P < 0.001) and PCV (P = 0.020), and in the fellow eyes of typical AMD (P < 0.001) and PCV (P = 0.027). In eyes without choroidal hyperpermeability, the mean subfoveal choroidal thickness was greater in PCV than that in typical AMD (P = 0.001). Choroidal thickness decreased after photodynamic therapy combined with intravitreal ranibizumab in typical AMD (P = 0.016) and PCV (P = 0.036). In eyes with PCV, the I62V polymorphism in the CFH gene contributed to choroidal thickness (P = 0.043). CONCLUSIONS Choroidal thickness is related to the AMD subtypes, choroidal hyperpermeability, and I62V CFH gene polymorphism. In eyes without choroidal hyperpermeability, EDI-OCT is useful as an auxiliary measure for differentiating typical AMD and PCV.

High-resolution imaging of resolved central serous chorioretinopathy using adaptive optics scanning laser ophthalmoscopy.

OBJECTIVE To compare pathologic changes in photoreceptors in eyes with resolved central serous chorioretinopathy (CSC) seen on high-resolution images obtained by adaptive optics scanning laser ophthalmoscopy (AO SLO) with visual acuity (VA) and findings on spectral-domain optical coherence tomography (SD OCT). DESIGN Observational case series. PARTICIPANTS Forty-five eyes of 38 patients with resolved CSC and 20 normal eyes of 20 volunteer subjects. METHODS All patients underwent a full ophthalmologic examination, SD OCT, and imaging with an original prototype AO SLO system fabricated using liquid crystal-on-silicon technology. MAIN OUTCOME MEASURES Cone mosaic patterns and cone density on AO SLO images and VA in eyes with CSC. RESULTS In normal eyes, AO SLO images showed a regular photoreceptor mosaic pattern and average cone densities 0.2, 0.5, and 1.0 mm from the central fovea of 67,900, 33,320, and 14,450 cones/mm(2). In eyes with CSC, cone densities were significantly lower at each distance from the central fovea (P = 0.009 at 0.2 mm, P = 0.007 at 0.5 mm, and P = 0.004 at 1.0 mm), and 2 distinct cone mosaic patterns were seen. Group 1 CSC eyes had regular cone mosaic patterns with small dark regions. Group 2 CSC eyes had irregular mosaic patterns with large dark regions. Compared with group 1, group 2 had significantly lower average cone density and worse average logarithm of the minimum angle of resolution (logMAR) VA (P<0.001). Mean cone density in eyes with disruptions in the photoreceptor inner and outer segment (IS/OS) junction or in the intermediate line on SD OCT images was significantly lower than that in eyes with an intact IS/OS junction or intermediate line (P<0.001 for both). Cone density 0.2 mm from the central fovea correlated with logMAR VA and mean foveal thickness (1-mm diameter area) measured on SD OCT images (P<0.001 for both). CONCLUSIONS Adaptive optics SLO images showed abnormal cone mosaic patterns and reduced cone densities in eyes with resolved CSC, and these abnormalities were associated with VA loss, suggesting that AO SLO is a useful means to detect and measure cone abnormalities associated with VA loss in these eyes.

Three-Dimensional Profile of Macular Retinal Thickness in Normal Japanese Eyes

PURPOSE To demonstrate the three-dimensional macular thickness distribution in normal subjects by spectral domain optical coherence tomography (SD-OCT) and evaluate its association with sex, age, and axial length. METHODS Mean regional retinal thickness measurements on the Early Treatment Diabetic Retinopathy Study (ETDRS) layout were obtained by three-dimensional raster scanning (6 x 6 mm) using SD-OCT in 248 normal eyes of 248 Japanese subjects. RESULTS Mean foveal thickness was 222 +/- 19 microm; it was significantly greater in men (226 +/- 19 microm) than in women (218 +/- 18 microm; P = 0.002) and did not correlate with age in either sex. Mean sectoral retinal thickness was also significantly greater in the men than in the women in all the quadrants of the inner ring (1-3 mm; P < 0.001 and P = 0.001-0.007) and in the temporal quadrant of the outer ring (3-6 mm; P < 0.001). The retinal thicknesses of each of the ETDRS sectors did not correlate significantly with axial length after adjustment for age in either sex. Retinal thickness in six of the eight sectors in the inner and outer rings showed a negative correlation with age after adjustment for axial length in the men (P < 0.001 and P = 0.001-0.018), whereas no correlation with age was observed in the women. CONCLUSIONS SD-OCT demonstrated the three-dimensional macular thickness distribution in normal eyes. Macular thickness varied significantly with sex and age. These variables should be considered while evaluating macular thickness.

Prevalence and Genomic Association of Reticular Pseudodrusen in Age-Related Macular Degeneration

PURPOSE To survey the prevalence of reticular pseudodrusen in late age-related macular degeneration (AMD) using multiple imaging methods, and to investigate the association between reticular pseudodrusen and polymorphisms in complement factor H (CFH) and age-related maculopathy susceptibility 2 (ARMS2) genes. DESIGN Retrospective case series. METHODS This study included 216 consecutive patients with late AMD (typical AMD, polypoidal choroidal vasculopathy [PCV], retinal angiomatous proliferation [RAP], or geographic atrophy). Eyes were assessed for reticular pseudodrusen using the blue channel of color fundus photography, infrared reflectance, fundus autofluorescence, and spectral-domain optical coherence tomography. The major AMD-associated single nucleotide polymorphisms (CFH Y402 rs1061170, CFH I62V rs800292, and ARMS2 A69S rs10490924) were genotyped. RESULTS Forty-nine eyes of 30 patients had a reticular pattern in ≥2 imaging modalities and were diagnosed with reticular pseudodrusen. Of these, 16 had bilateral late AMD, whereas 32 of 186 patients without reticular pseudodrusen had bilateral late AMD (P < .001). The prevalence of reticular pseudodrusen was 83% in RAP, 50% in geographic atrophy, 9% in typical AMD, and 2% in PCV. The frequency of the T allele in ARMS2 A69S in patients with and without reticular pseudodrusen was 78.6% and 59.9%, respectively (P=.007). CONCLUSIONS The prevalence of reticular pseudodrusen was low in PCV cases. About 50% of patients with reticular pseudodrusen had bilateral late AMD. The connection of ARMS2 risk allele and reticular pseudodrusen was confirmed in a Japanese population.

Factors Associated With the Response of Age-Related Macular Degeneration to Intravitreal Ranibizumab Treatment

PURPOSE To investigate factors affecting patient response to intravitreal ranibizumab treatment for age-related macular degeneration (AMD). DESIGN Retrospective chart review. METHODS We reviewed medical records of 105 consecutive eyes with AMD treated with intravitreal ranibizumab injections and followed for more than 1 year after treatment. Response to ranibizumab treatment was compared between typical neovascular AMD and polypoidal choroidal vasculopathy (PCV). Furthermore, we investigated associations of age, lesion size, and single nucleotide polymorphisms (SNPs) in CFH and ARMS2 genes with treatment response. RESULTS Forty-nine eyes were diagnosed with typical neovascular AMD and 56 eyes with PCV. Serous retinal detachment and retinal edema resolved similarly in both typical neovascular AMD and PCV after treatment. However, visual acuity (VA) significantly improved in eyes with PCV, whereas VA was maintained in typical neovascular AMD. At the third and twelfth months after injection, VA was better in PCV than in typical neovascular AMD (P = .027 and P = .044, respectively), although there were no differences in baseline VA between the 2 groups. Age and size of greatest linear dimension were significantly associated with visual prognosis in typical neovascular AMD but not in PCV. There was no clear association between 3 SNPs and responsiveness to ranibizumab treatment. CONCLUSIONS Although exudative changes were equivalent following ranibizumab treatment in both typical neovascular AMD and PCV, there was a significant increase in VA in PCV compared to typical neovascular AMD. Age and greatest linear dimension correlated with visual prognosis only in typical neovascular AMD and not in PCV.

Sensitivity and specificity of detecting reticular pseudodrusen in multimodal imaging in Japanese patients.

Purpose: To identify reticular pseudodrusen (RPD) in age-related macular degeneration using multiple imaging modalities, including the blue channel image of fundus photography, infrared reflectance (IR), fundus autofluorescence, near-infrared fundus autofluorescence, confocal blue reflectance, indocyanine green angiography, and spectral-domain optical coherence tomography (SD-OCT), and to compare the sensitivities and specificities of these modalities for detecting RPD. Methods: This study included 220 eyes from 114 patients with newly diagnosed age-related macular degeneration. Patients underwent fundus photography, IR, fundus autofluorescence, near-infrared fundus autofluorescence, confocal blue reflectance, indocyanine green angiography, and SD-OCT in both eyes. Eyes were diagnosed with RPD if they showed reticular patterns on at least two of the seven imaging modalities. Results: Thirty-seven eyes were diagnosed with RPD. However, SD-OCT and IR had the highest sensitivity (94.6%), and at the same time, SD-OCT had a high specificity (98.4%). The blue channel of color fundus photography, confocal blue reflectance, and indocyanine green angiography had a specificity of 100% but had lower sensitivity than that of SD-OCT and IR. Conclusion: For detecting RPD, IR and SD-OCT had the highest sensitivity. Although SD-OCT had the highest sensitivity and specificity, RPD detection should be confirmed using more than one modality for increased accuracy.