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Purpose: Following on from reports of retrograde retinal signaling in mice, we sought to investigate the influence of age and retinal location on this phenomenon using mice that lack rods and the majority of cones., Methods: We used functional anatomy for c-fos (Fos) and tyrosine hydroxylase (TH) to measure light-driven activation of dopamine neurons along a dorsal-ventral transect in C3H/He wild-type and rodless-coneless rd/rd cl (rdcl) mice aged 3, 5, and >14 months. A parallel series of retinae from 3-month-old mice was also stained for cone opsins and melanopsin., Results: Analysis by confocal microscopy revealed light-driven Fos activation in TH cells residing in the middorsal retina of the youngest rdcl mice. This region was largely devoid of residual cones but contained a large number of intrinsically photosensitive retinal ganglion cells (ipRGCs) and the highest density of melanopsin neurites. With advancing age, there was a paradoxical increase in retrograde signaling from ∼3% Fos-positive (Fos+) TH cells at 3 months to ∼36% in rdcl mice >14 months. This increased activation occurred in more central and peripheral retinal regions., Conclusions: Our data provide new insights into the anatomy and plasticity of retrograde melanopsin signaling in mice with severe rod/cone dystrophy. The increased retrograde signaling we detect may result from either an increased potency of melanopsin signaling with advancing age and/or postsynaptic modification to dopaminergic neurons.

Purpose: Cultured retinal pigment epithelium (RPE) may become a therapeutic option for transplantation in retinal disease. However maintaining a native RPE phenotype in vitro has proven challenging. The human RPE cell-line ARPE-19 is used widely as an alternative to primary RPE. It is grown in DMEM/F12 medium as standard, but its phenotype is dependent on culture conditions, and many differentiation markers are usually absent. The purpose of this study was to examine how this sensitive phenotype of ARPE-19 can be modulated by growth media with or without the metabolite pyruvate to elucidate better RPE growth conditions., Methods: ARPE-19 cells at passages p22 to p28 were cultured on filters for up to 3 months in DMEM/F12 or DMEM media with or without pyruvate and 1% fetal calf serum. Assessment of differentiation was performed using pigmentation, immunocytochemistry, protein/mRNA expression, transepithelial resistance, VEGF secretion, and ultrastructure., Results: Pyruvate, in combination with DMEM, induced dark pigmentation and promoted differentiation markers such as CRALBP and MerTK. Importantly, RPE65 protein was detected by Western blotting and was enhanced by pyruvate, high glucose, and DMEM. ARPE-19 cells maintained in this medium could also phagocytose human photoreceptor outer segments (POS). VEGF secretion was greater in DMEM cultures and was affected by glucose but not by pyruvate. Pigmentation never occurred in DMEM/F12., Conclusions: This study demonstrated important differentiation markers, including pigmentation and Western blots of RPE65 protein, and showed human POS phagocytosis in ARPE-19 cultures using a simple differentiation protocol. The results favor the use of high-glucose DMEM with pyruvate for future RPE differentiation studies.

Purpose: To report the frequency and origins of increased fundus autofluorescence (AF) in age-related macular degeneration using the model of macular translocation., Methods: In this retrospective observational case series, postoperative serial fundus AF images from 40 consecutive patients were examined. The origin of well-delineated increased AF changes was explored by examining simultaneous spectral-domain optical coherence tomography (SD-OCT) scans and coregistered microperimetry., Results: AF images were taken between a mean of 13 and 36 months. Seven patients were excluded from analysis because of lack of postoperative AF imaging or extensive macular RPE atrophy. Of the remaining patients, 9 had masking pattern of foveal AF, 21 had small, round increased AF lesions in the fovea, and 3 had a near normal pattern of foveal hypo-AF. Parafoveal increased AF was seen in all 33 patients in 1 of 3 patterns: well-delineated homogenous increased AF patches (17), curvilinear increased AF bands (4), and speckled increased AF (12). Simultaneous SD-OCT showed loss of signal from the interface of the inner and outer segments of the photoreceptor cell layer with variable loss of outer nuclear layer thickness. Microperimetry showed subnormal retinal sensitivity in regions with increased AF. Parafoveal increased AF size remained stable for 2 to 5 years of follow-up., Conclusions: SD-OCT and microperimetry changes observed after translocation may be attributed to shortening of the outer segments. A corresponding reduction of visual pigment in the shortened outer segments may lead to an unmasking effect. Increased AF in some macular diseases may be attributed to unmasking of AF rather than to increased fluorophores within abnormal retina.

Purpose: To correlate the phenotype of four patients with inherited macular disease with the immunohistopathology of retinal tissue collected at the time of retinal pigment epithelium (RPE)-choroidal transplantation., Methods: A clinicopathologic case series describing the phenotype of four patients, including confocal immunohistochemistry and electron microscopy (EM), and the results of genetic testing., Results: In Case 1, electrophysiology showed only macular dysfunction. Confocal microscopy revealed minor abnormalities. EM showed abnormal cone inner segments with swollen mitochondria. In case 2 (R172W mutation in RDS), electrophysiology demonstrated generalized cone system dysfunction with severe macular involvement. Peripherin labeling of outer segments was nonuniform, and EM showed discs arranged in whorllike structures. Case 3 showed severe central macular dysfunction on multifocal electroretinogram (ERG). Peripherin staining was irregular and disorganized. EM revealed abnormal inner segment morphology, particularly in rods, and disorganized irregular outer segments. Case 4 had localized central macular dysfunction on multifocal ERG. Confocal microscopy was grossly normal, with evidence of early redistribution of cone opsin to the inner segment. EM showed variable rod morphology and normal cones., Conclusions: RPE transplantation provides a unique opportunity to gain insight into retinal disorders by enabling phenotypic correlation with the immunohistopathology of retinal tissue collected during surgery.

Purpose: To determine the test-retest variability of the retinal sensitivity of the Nidek MP1 microperimeter in patients with macular disease., Methods: In this prospective study, 50 patients were enrolled with a range of macular diseases. One examiner performed two consecutive microperimetry tests for all patients using the same test strategy. Test-retest variability for mean sensitivity (MS), mean deviation (MD), point-wise sensitivity (PWS), local defect classification (LDC), average sensitivity for the central macula (CMS, 16 loci inside 10 degrees ), paracentral macular sensitivity (PMS, 52 loci in the 10 to 20 degrees ring), and dense scotoma size (DSS) were analyzed by calculating the 95% coefficients of repeatability or percentage agreement., Results: Mean (SD) age and visual acuity were 61 (15) years and 0.34 (0.32) logMAR, respectively. The mean difference in MS between tests 1 and 2 was +0.2 dB (SD, 0.9 dB; P = 0.127). The coefficients of repeatability for MS, MD, CMS, and PMS were 1.81, 2.56, 2.13, and 1.93 dB, respectively. The mean (SD) of coefficients of repeatability for PWS across all 68 loci was 5.56 (0.86) dB. Of all test loci in all patients 76% had perfect agreement in LDC, and 94% of patients had a change in DSS of four or fewer test loci., Conclusions: Test-retest variability was lowest for MS and highest for PWS. However, MS does not provide spatial information. The authors recommend the use of CMS and PMS for monitoring macular function and consider a change of greater than 2.56 and 2.31 dB (the upper limit of the 95% confidence interval of their coefficients of repeatability), respectively, to exceed test-retest variability.

Purpose: To compare the long-term outcomes of macular translocation (MT) and autologous RPE-choroid patch graft (PG) in patients with neovascular age-related macular degeneration (AMD)., Methods: This is a retrospective review of the first 12 patients who underwent MT and the first 12 patients who underwent PG. Visual acuity (VA), contrast sensitivity (CS), clinical findings, and complications were recorded. Microperimetry and fundus imaging were reviewed. Outcome measures were the change in VA and CS over 3 years in each group and rates of complication. Microperimetry and fixation in three best cases from each group were described., Results: The two groups were matched for age and VA. Median follow-up durations were 41 (MT) and 38 (PG) months. Median VA (logMAR) was maintained in the MT group: 0.90 at baseline and 0.69 at 3 years (P=0.09) whereas in the PG group, median VA declined from 0.87 to 1.38 at 3 years (P<0.001). Both surgical modalities had high rates of detachment and macular edema. Although more extensive RPE damage occurred in PG, the graft resisted growth of recurrent choroidal neovascularization toward the fovea. Near normal VA was achievable by each technique but macular sensitivity and fixation stability were superior in the MT group., Conclusions: In the present cohort, MT maintained VA for 3 years but PG did not. This outcome may be related to the differences in surgical approach, source of RPE, and choroidal perfusion. The authors recommend MT in preference to PG for treatment of patients with the second eye affected by neovascular AMD unsuitable for other treatment.

Purpose: To describe the outcomes of autologous retinal pigment epithelium (RPE)-choroid graft in macular dystrophy., Methods: In this prospective interventional case series, five patients with macular dystrophy were enrolled to undergo autologous RPE-choroid patch graft between August 2005 and January 2007. All patients received preoperative and postoperative evaluations including visual acuity, contrast sensitivity, reading ability, microperimetry, fluorescein angiography, indocyanine green angiography, fundus autofluorescence (AF) imaging, and optical coherence tomography (OCT)., Results: Patients were followed up for an average of 13.4 (9-23) months. Two patients gained reading acuity but only one regained visual task function after graft. This was maintained for approximately 12 months. Although there is an overall loss of visual acuity, contrast sensitivity, and reading ability, postoperative microperimetry demonstrated retinal sensitivity over the graft in all patients with maximum sensitivity, using a Goldmann size III stimulus of 200-ms duration, ranging from 12 to 20 dB. After surgery, one patient developed retinal detachment and two required cataract extraction at the time of removal of oil. ICG angiography demonstrated perfusion of the graft in four patients. With image registration, homogenous AF pattern in areas of the graft was found to be associated with retinal sensitivity., Conclusions: Autologous RPE-choroid graft can be performed in patients with macular dystrophy. Although microperimetry showed evidence of retinal function over a perfused and autofluorescent graft, the overall loss of visual acuity and reading ability raises concerns over the use of this novel surgical technique in these patients.

Purpose: To use progenitor cells isolated from the neural retina for transplantation studies in mice with retinal degeneration., Methods: Retinal progenitor cells from postnatal day 1 green fluorescent protein-transgenic mice were isolated and characterized. These cells can be expanded greatly in culture and express markers characteristic of neural progenitor cells and/or retinal development., Results: After they were grafted to the degenerating retina of mature mice, a subset of the retinal progenitor cells developed into mature neurons, including presumptive photoreceptors expressing recoverin, rhodopsin, or cone opsin. In rho-/- hosts, there was rescue of cells in the outer nuclear layer (ONL), along with widespread integration of donor cells into the inner retina, and recipient mice showed improved light-mediated behavior compared with control animals., Conclusions: These findings have implications for the treatment of retinal degeneration, in which neuronal replacement and photoreceptor rescue are major therapeutic goals.

Purpose: To assess the capacity of a retrovirus-engineered Schwann cell line (SCTM41), transfected with either a glial cell line-derived neurotrophic factor (GDNF) construct or a brain-derived neurotrophic factor (BDNF) construct, to sustain visual function in the dystrophic Royal College of Surgeons (RCS) rat., Methods: Cell suspensions were injected into the subretinal space of the right eye of 3-week-old dystrophic RCS rats through a transscleral approach. The left eye remained as an unoperated control. Sham-surgery animals received injections of carrier medium plus DNase to the right eye. All animals were placed on oral cyclosporine. At 8, 12, 16, and 20 weeks of age, animals were placed in a head-tracking apparatus and screened for their ability to track square-wave gratings at various spatial frequencies (0.125, 0.25, and 0.5 cyc/deg). At the end of the experiment, the animals were perfused and processed for histologic assessment of photoreceptor survival., Results: Animals with SCTM41-GDNF-secreting cells, on average, head tracked longer than animals with SCTM41-BDNF-secreting cells, and both performed better than those injected with the parent SCTM41 line. All tracked longer than sham-surgery or nonsurgical dystrophic eyes. Each cell type demonstrated preservation of photoreceptors up to at least 4 months of age, over and above the sham-surgery control., Conclusions: Engineered Schwann cells sustain retinal structure and function in the dystrophic RCS rat. Cells overexpressing GDNF or BDNF had a greater effect on photoreceptor survival than the parent line or sham surgery. This study demonstrates that ex vivo gene therapy and subsequent cell transplantation can be effective in preserving photoreceptors from the cell death that normally accompanies retinal degeneration.

Purpose: To determine whether subretinal Schwann cell transplantation can prolong the survival of photoreceptors in the rhodopsin knockout (rho(-/-)) mouse., Methods: Schwann cells were prepared from postnatal day (PN) 5 to 7 mouse pups and grafted subretinally into the eyes of PN35 rho(-/-) mice. RT-PCR was performed on similarly prepared cells to determine growth factor production in vitro. Eyes were retrieved at PN70 for anatomic and statistical analysis. Control animals received grafts of fibroblasts or sham surgery., Results: RT-PCR demonstrated the presence of message for ciliary neurotrophic factor (CNTF), brain-derived neurotrophic factor (BDNF), and glia-derived neurotrophic factor (GDNF) in the cultured Schwann cells. Schwann cell grafts produced a statistically significant rescue of photoreceptors in a restricted area of retina at PN70, but the effect was lost by PN140. Preserved inner segments could be identified, but outer segments were never present. Sham surgery also resulted in photoreceptor rescue but at a reduced level. Fibroblast grafts appeared to produce little or no rescue effect. Grafts of Schwann cells or fibroblasts and sham surgery induced a reactive Müller glial response., Conclusions: Schwann cells can prolong photoreceptor survival in the rhodopsin knockout mouse until at least PN70.