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Purpose. Transplantation of stem, progenitor, or precursor cells has resulted in photoreceptor replacement and evidence of functional efficacy in rodent models of retinal degeneration. Ongoing work has been directed toward the replication of these results in a large animal model, namely, the pig. Methods. Retinal progenitor cells were derived from the neural retina of GFP-transgenic pigs and transplanted to the subretinal space of rhodopsin Pro347Leu-transgenic allorecipients, in the early stage of the degeneration and the absence of immune suppression. Results. Results confirm the survival of allogeneic porcine RPCs without immune suppression in the setting of photoreceptor dystrophy. The expression of multiple photoreceptor markers by grafted cells included the rod outer segment-specific marker ROM-1. Further evidence of photoreceptor differentiation included the presence of numerous photoreceptor rosettes within GFP-positive grafts, indicative of the development of cellular polarity and self-assembly into rudiments of outer retinal tissue. Conclusion. Together, these data support the tolerance of RPCs as allografts and demonstrate the high level of rod photoreceptor development that can be obtained from cultured RPCs following transplantation. Strategies for further progress in this area, together with possible functional implications, are discussed.

The purpose of this study was to establish the intravitreal (ITV) pharmacokinetics of glial cell line-derived neurotrophic factor (GDNF) and observe possible complications after ITV injection. Twenty Danish landrace pigs and 34 eyes were included in the study; 30 were injected with 100 ng of GDNF, two controls were injected without GDNF, and two received no injection. At post-injection time points of 1, 2, 3, 6 hours (h), 1, 2, 4 or 7 days (d) eyes were enucleated and the ITV concentration of GDNF (cGDNF) was determined by enzyme-linked immunosorbent assay, and activity was tested using a retinal ganglion cell line (RGC5) bioassay. Indirect ophthalmoscopy, intraocular pressure assessment, and fundus photography were performed before enucleation. There was initial variability in the cGDNF, but after 24h GDNF was cleared in a monoexponential fashion with a half-life of 37 h (CL 33-43 h). Therapeutic concentrations were present for 15 d (CL 13-18d) when an extrapolation was done. GDNF-injected vitreous samples stimulated increased survival of RGC5s at 24h post-delivery (p=0.002) compared with no-GDNF vitreous controls. This effect was independent of intraocular incubation time when cGDNF was normalized to 5 ng/ml. A semi-logarithmic dose-response curve showed linearity between 0.1 and 10 ng/ml. None of the eyes showed any signs of inflammation or other complications. A single ITV GDNF injection of 100 ng leads to therapeutic levels for 15 days in the porcine eye. The GDNF was stable in the intraocular environment and no adverse events were observed. GDNF might therefore play a role in the future treatment of acute retinal damage.

Udgivelsesdato: 2009-Aug-18, AIM: To examine postoperative macular morphology and visual outcome after 12 months in relation to internal limiting membrane (ILM) peeling versus no peeling, indocyanine green (ICG)-staining, and reoperation in eyes that achieved macular hole closure after surgery. METHODS: Seventy-four eyes with closed stage 2 or 3 macular holes were recruited from a randomized clinical trial comparing (1) vitrectomy without ILM peeling, (2) vitrectomy with 0.05 % isotonic ICG-assisted ILM peeling, and (3) vitrectomy with 0.15 % trypan blue-assisted ILM peeling. Contrast-enhanced Stratus optical coherence tomography was used to assess central foveal thickness (CFT), central photoreceptor layer thickness (CPRT), central photoreceptor layer disruption (PRD) and relative reflectivity of the outer nuclear layer (ONL-RR). Outcomes were correlated with best-corrected visual acuity (BCVA) 12 months after surgery. RESULTS: BCVA was correlated with CPRT and PRD. Regression analysis and receiver operating characteristics curve analysis showed that CPRT > 33 microm (odds-ratio = 12.5) and PRD < 177 microm (odds-ratio = 9.86) were highly predictive for regaining reading vision (>/= 69 early treatment of diabetic retinopathy study letters) 12 months after surgery. No significant difference was found in postoperative macular morphology between subgroups. CONCLUSIONS: Poor vision after 12 months despite macular hole closure was associated with attenuation and disruption of the foveolar photoreceptor matrix. The extent of attenuation and disruption was independent of peeling and staining. ClinicalTrials.gov Identifier: NCT00302328.

Udgivelsesdato: 2009-Sep, Calcium-independent phospholipase A2, group VIA (iPLA2-VIA) is involved in cell proliferation. This study aimed to evaluate the role of iPLA2-VIA in retinal pigment epithelium (RPE) cell proliferation and in retinal diseases involving RPE proliferation. A human RPE cell line (ARPE-19) was used to explore this role in vitro. Proliferating ARPE-19 cells had increased expression and activity of iPLA2-VIA. iPLA2-VIA was found in the nuclei of proliferating ARPE-19 cells, whereas in confluent ARPE-19 cells, with limited proliferation, iPLA2-VIA was primarily found in the cytosol. Inhibition of iPLA2-VIA decreased the rate of proliferation, whereas over expression of iPLA2-VIA increased the rate of proliferation. Using an experimental porcine model of RPE proliferation we demonstrated significant nuclear upregulation of iPLA2-VIA in proliferating RPE cells in vivo. We furthermore evaluated the expression of iPLA2-VIA in proliferative vitreoretinopathy (PVR). PVR membranes revealed nuclear expression of iPLA2-VIA in the RPE cells which had migrated and participated in the formation of the membranes. Overall, the present results point to an important role of iPLA2-VIA in the regulation of RPE proliferation suggesting that iPLA2-VIA may be considered as a possible pharmaceutical target in retinal diseases involving RPE proliferation and migration.

AIMS: We investigated the effect of several Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), on the preoptic nerve oxygen tension (ONPO2), as indomethacin previously has demonstrated a strong decreasing effect on ONPO2. We tested whether these NSAIDs, like indomethacin, also reduce the increasing effect of dorzolamide on ONPO2. METHODS: ONPO2 was measured 0.5 mm above the optic disc in 23 domestic pigs (26-36 kg) with a polarographic oxygen-sensitive electrode. One of the following NSAIDs was administered intravenously as increasing doses or as one large dose: indomethacin, ibuprofen, diclofenac, ketoprofen, parecyclo-oxygenase-2 inhibitor and lornoxicam. Indomethacin was both tested alone and after preceding administration of the other NSAIDs. Dorzolamide was also tested after preceding administration of NSAIDs different from indomethacin. RESULTS: Indomethacin decreased ONPO2 significantly in a dose-dependent manner. None of the other NSAIDs produced any effect on the ONPO2 (p>>0.05; n = 17). No difference was found between the effect of indomethacin injected alone, and after preceding administration of the other NSAIDs. Intravenous dorzolamide (500 mg) increased ONPO2 by 32 (7)% (n = 7; p<0.001) after preceding administration of several NSAIDs different from indomethacin. CONCLUSIONS: Indomethacin decreased ONPO2, while the other NSAIDs showed no effect on ONPO2, and they did not affect the effect of indomethacin. The hypoxic effect of indomethacin must be due to another mechanism than cyclo-oxygenase inhibition. The effect of dorzolamide on ONPO2 is not related to prostaglandin production Udgivelsesdato: 2008/1, We investigated the effect of several Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), on the preoptic nerve oxygen tension (ONPO2), as indomethacin previously has demonstrated a strong decreasing effect on ONPO2. We tested whether these NSAIDs, like indomethacin, also reduce the increasing effect of dorzolamide on ONPO2.

Udgivelsesdato: 2008/12

Udgivelsesdato: 2008/3/17