Non-Paraneoplastic Autoimmune Retinopathy: The First Case Report in Korea

Autoimmune retinopathy (AIR) is an immune-mediated retinopathy, resulting from an immunologic process caused by the aberrant recognition of retinal antigens as autoantigens. The diagnosis of AIR involves the detection of antiretinal antibodies with concurrent clinical and electrophysiological evidence of retinopathy. A 40-year-old patient presented with progressive loss of bilateral vision over several months. A fundus examination was unremarkable. Spectral domain optical coherence tomography revealed a blurred photoreceptor ellipsoid zone at the subfoveal region in both eyes with more prominent disruption in the left eye. Full-field electroretinography (ERG) showed relatively normal rod and cone responses in the right eye, and decreased photopic bwaves with minimal attenuation of a-waves in the left eye. Multifocal ERG demonstrated slightly reduced amplitude of the inner segment ring in the right eye and decreased amplitudes and delayed latencies of all modalities in the left eye. The patient was suspected to have AIR and it was supported by positive Western blots for 23-kDa protein, enolase (46-kDa), aldolase (40-kDa), 62-kDa and 78-kDa proteins and by immunohistochemical staining of human retinal bipolar and ganglion cells. Despite the immunosuppressive treatment, the destruction of the retinal photoreceptors progressed, and immunosuppressive interventions produced very little visual improvement. We report on what is, to the best of our knowledge, the very first case of serologically confirmed nonparaneoplastic AIR in Korea.

Induce and differenctiation of marrow mesenchymal stem cell into photoreceptor-like cell in vitro and microenvironment / 中华实验眼科杂志

Background Marrow mesenchymal stem cells (MSCs) has been successful induced to differentiate into corneal cells,retinal ganglion cells (RGCs) and retinal neuron-like cells in recent years,but there are few studies about MSCs induced into photoreceptor cells and their microenvironment.Objective The aim of this study was to explore the induce and differentiation of bone marrow mesenchymal stem cells (BMSCs) into photoreceptor-like cells in vitro and microenvironment.Methods The second generation of human BMSCs strain and RPE cells strain were cultured and passaged,respectively,and the fourth generation of BMSCs and the third generation of RPE cells were used in the experiment.BMSCs were cocultured using the mesenchymal stem cells medium (MSCM) contained 20 μg/L basic fibroblast growth factor (bFGF),20 μg/L epithelial growth factor (EGF)and 20 μg/L brain derived neurotrophic factor (BDNF) with RPE cells to induce the differentiation of BMSCs in the induced group,and BMSCs were cultured in MSCM only in the control group.The morphology of induced and differentiated cells were observed under the inverted microscope.Inmmunocytochemistry was used in induced for 3-,5-,7-day cells to detect the expression rate of rhodopsin protein for the identification of phenotype of the differentiated cells.RT-PCR was used in induced for 5-,7-day cells to detect the expressions of rhodopsin mRNA and recoverin mRNA.Results Cultured BMSCs grew well with the spindle shape,and passaged RPE cells showed the uniform size and polygon shape with the abundant pigment in the cells.Some induced cells appeared to be the neuron-like cells with round shape and long prominence and the secondary reticular branches.The expression rates of rhodopsinin the cells were (5.83±0.29)％,(20.36±0.32)％ and (29.80±2.30)％ in the third,fifth and seventh day after induce,which were significantly higher than (0.71 ±0.35) ％,(2.56±0.24) ％ and (2.32±0.42) ％ of control cells (t3 d =41.510,t5d =107.290,t7 d =30.036,P＜0.01).The grey scales of rhodopsin mRNA and recoverin mRNA were significantly elevated in the induced and differentiated cells compared with control cells in the fifth and seventh day (rhodopsin mRNA:t5 d =103.506,t7 d =122.584,P＜0.01 ; recoverin mRNA:t5 d =106.674,t7 d =189.992,P＜0.01).Conclusions BMSCs can be successfully induced to differentiate into photoreceptor cells after cocultured by conditioned medium with RPE cells.

Down-regulation of interphotoreceptor retinoid-binding protein and up-regulation of recoverin expression in rats with N-methyl-N-nitrosourea-induced retinal damages / 中华眼底病杂志

Objective To investigate the effect of N-methyl-N-nitrosourea (MNU) on expressions of interphotoreceptor retinoid-binding protein (IRBP) and recoverin in rat retinal.Methods Thirty female Sprague-Dawley (SD) rats were randomly divided into five groups,including normal control group,and MNU treatment one day,three days,seven days and 10 days groups,each group had six rats.Rats in MNU-treatment groups received a single intraperitoneal injection of 40 mg /kg MNU,while rats in the normal control group received intraperitoneal injection of saline 5 ml/kg.Reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence were used to detect the retinal expression of IRBP and recoverin.Results RT-PCR results indicated that retinal IRBP levels decreased after MNU injection compared with normal control (P＜0.01),while recoverin levels increased (one day:P＞0.05; three days:P＜0.05; seven days:P＜0.5; 10 days:P＜0.05).Immunofluorescence assays demonstrated that normally IRBP protein is mainly in the inner and outer segments of photoreceptors.After MNU treatment,IRBP protein was detected in all retinal layers but much faint.Recoverin was expressed in the inner nuclear layer,inner plexiform layer and ganglion cell layer,and its expression was increased after MNU injection.Conclusion MNU suppresses IRBP expression and promotes recoverin expression in rat retina.

Intravenously Administered Anti-recoverin Antibody Alone Does Not Pass through the Blood-Retinal Barrier

PURPOSE: Cancer-associated retinopathy is a paraneoplastic retinal degeneration which may primarily result from auto-immune mediated apoptosis. It has been hypothesized that high titer of auto-antibodies are able to cross the blood-retinal barrier (BRB) and to enter retinal cells to activate apoptotic pathway which has been already well-established. However, it still remains to be elucidated whether auto-antibodies could cross BRB in the retina. Herein, we demonstrated that intravenously administrated anti-recoverin antibodies could not pass through BRB and not lead to retinal cell death. METHODS: Anti-recoverin antibody was intravenously injected to C57BL/6 mice, which were sacrificed 1 and 7 days to obtain eye. Vascular endothelial growth factor was intravitreally injected to induce BRB breakdown, which was confirmed by fluorescein angiography and western blotting for zonula occludens (ZO)-1, ZO-2 and occludin. To investigate the location of anti-recoverin antibody in the retina, immunofluorescein was performed. The retinal toxicity of intravenous anti-recoverin antibody was evaluated by histological examination and transferase-mediated dUTP nick-end labeling. Immunofluorescein staining for glial fibrillary acidic protein was done to address glial activation as well. RESULTS: Intravenously administrated anti-recoverin antibodies were exclusively distributed on retinal vessels which were co-localized with CD31, and led to neither increase of glial fibrillary acidic protein expression, as an indicator of retinal stress, nor apoptotic retinal cell death. Moreover, even in the condition of vascular endothelial growth factor-induced BRB breakdown, anti-recoverin antibodies could not migrate across BRB and still remained on retinal vessels without retinal cytotoxicity. CONCLUSIONS: Our results suggest that high titer of intravascular anti-recoverin antibodies could not penetrate into the retina by themselves, and BRB breakdown mediated by dysregulation of tight junction might not be sufficient to allow anti-recoverin antibodies to pass through BRB.

Differentiation of Recoverin Immunoreactive Cone Bipolar Cells and Their Timing of Synaptic Formation with GABAergic Amacrine Cells in the Rat Retina / 대한해부학회지

Recoverin is a member of the large family of EF-hand calcium binding proteins (Baimbridge et al., 1992), and it is thought to be involved in the regulation of phosphodiesterase in photoreceptors and in the phosphorylation of activated rhodopsin (Polans et al., 1996). Although the functional significance of recoverin in cone bipolar cells is not fully understood, the antiserum against recoverin has been widely used to identify a certain population of cone bipolar cells (Milam et al., 1993; Sasso's Pognetto et al., 1994; Euler & W sle, 1995). GABA is well known to act as major neurotransmitters in the mammalian central nervous system including retina. This study was conducted to identify the development process of recoverin-labeled cone bipolar cells, and the timing points of synaptic formation of the labeled bipolar cells and GABAergic amacrine cells in the rat retina. The results were as follows; In the adult rat retina, recoverin-labeled cone bipolar cells were subdivided into twotypes; type 2 cells with axon terminal stratified in sublamina a of the inner plexiform layer (IPL), and type 8 cells with axon terminals stratified in sublamina b of the IPL. Recoverin-labeled cone bipolar cells began to appear from postnatal day 5. The axon terminals of recoverin-labeled type 2 cone bipolar cells stratified at postnatal day 10, while those of type 8 cone bipolar cells stratified at postnatal day 13. The axon terminals of type 2 cone bipolar cells made ribbon synapses onto GABAergic amacrine cells in the IPL at postnatal day 10. These results demonstrate that recoverin-labeled type 2 cone bipolar cells differentiate earlier than recoverin-labeled type 8 cone bipolar cells, and suggest that GABAergic amacrine cells may play important roles in visual processing of recoverin-labeled type 2 cone bipolar cells by making synapse onto these cells at early stage. Synapses between type 2 cone bipolar cells and GABAergic amacrine cells are formed about the time of postnatal day 10 for visual processing.