Effects of leptin on proliferation and differentiation of hypoxic rat retinal progenitor cells in vitro / 南方医科大学学报

OBJECTIVE@#To investigate the the effects of leptin on the proliferation, differentiation and PTEN expression of rat retinal progenitor cells (RPCs) cultured under hypoxic condition.@*METHODS@#SD rat RPCs were cultured in normoxic conditions or exposed to hypoxia in the presence of 0, 0.3, 1.0, 3.0, 10, and 30 nmol/L leptin for 12, 48 and 72 h, and the cell viability was assessed using cell counting kit 8 (CCK 8) assay. The RPCs in primary culture were divided into control group, hypoxia group, and hypoxia+leptin group, and after 48 h of culture, the cell medium was replaced with differentiation medium and the cells were further cultured for 6 days. Immunofluorescence staining was employed to detect the cells positive for β-tubulin III and GFAP, and Western blotting was used to examine the expression of PTEN at 48 h of cell culture.@*RESULTS@#The first generation of RPCs showed suspended growth in the medium with abundant and bright cellular plasma and formed mulberry like cell spheres after 2 days of culture. Treatment with low-dose leptin (below 3.0 nmol/L) for 48 h obviously improved the viability of RPCs cultured in hypoxia, while at high concentrations (above 10 nmol/L), leptin significantly suppressed the cell viability (P < 0.05). The cells treated with 3.0 nmol/L leptin for 48 h showed the highest viability (P < 0.05). After treatment with 3.0 nmol/L leptin for 48 h, the cells with hypoxic exposure showed similar GFAP and β-tubulin Ⅲ positivity with the control cells (P>0.05), but exhibited an obvious down-regulation of PTEN protein expression compared with the control cells (P < 0.05).@*CONCLUSION@#In rat RPCs with hypoxic exposure, treatment with low dose leptin can promote the cell proliferation and suppress cellular PTEN protein expression without causing significant effects on cell differentiation.

tiRNA-Val promotes angiogenesis via Sirt1-Hif-1α axis in mice with diabetic retinopathy

BACKGROUND: Diabetic retinopathy (DR) is a specific microvascular complication arising from diabetes, and its pathogenesis is not completely understood. tRNA-derived stress-induced RNAs (tiRNAs), a new type of small noncoding RNA generated by specific cleavage of tRNAs, has become a promising target for several diseases. However, the regulatory function of tiRNAs in DR and its detailed mechanism remain unknown. RESULTS: Here, we analyzed the tiRNA profiles of normal and DR retinal tissues. The expression level of tiRNA-Val was significantly upregulated in DR retinal tissues. Consistently, tiRNA-Val was upregulated in human retinal microvascular endothelial cells (HRMECs) under high glucose conditions. The overexpression of tiRNA-Val enhanced cell proliferation and inhibited cell apoptosis in HRMECs, but the knockdown of tiRNA-Val decreased cell proliferation and promoted cell apoptosis. Mechanistically, tiRNA-Val, derived from mature tRNA-Val with Ang cleavage, decreased Sirt1 expression level by interacting with sirt1 3'UTR, leading to the accumulation of Hif-1α, a key target for DR. In addition, subretinal injection of adeno-associated virus to knock down tiRNA-Val in DR mice ameliorated the symptoms of DR. CONCLUSION: tiRNA-Val enhance cell proliferation and inhibited cell apoptosis via Sirt1/Hif-1α pathway in HRMECs of DR retinal tissues.

Metaboloma use in ophthalmology / Uso de metaboloma em oftalmologia: uma revisão narrativa

ABSTRACT It is part of the omic sciences to search for an understanding of how the cellular system of organisms works as well as studying their biological changes. As part of the omic sciences, we can highlight the genomics whose function is the study of genes, the transcriptomics that studies the changes in the transcripts, the proteomics responsible for understanding the changes that occur in proteins, and the metabolomics that studies all the metabolic changes that occur in a certain system when it is submitted to different types of stimuli. Metabolomics is the science that studies the endogenous and exogenous metabolites in biological systems, which aims to provide comparative quantitative or semi-quantitative information about all metabolites in the system. This review aims to describe the main applications of metabolomics science in ophthalmolog. We searched the literature on main applications of metabolomics science in ophthalmology, using the MEDLINE and LILACS databases, with the keywords "metabolomics" and "ophthalmology", from January 1, 2009, to April 5, 2021. We retrieved 216 references, of which 58 were considered eligible for intensive review and critical analysis. The study of the metabolome allows a better understanding of the metabolism of ocular tissues. The results are important to aid diagnosis and as predictors of the progression of many eye and systemic diseases.

RESUMO Faz parte das ciências ômicas buscar entender como funciona o sistema celular dos organismos e estudar suas alterações biológicas. Como parte das ciências ômicas, destacam-se a genômica, cuja função é o estudo dos genes; a transcriptômica, que estuda as mudanças nos transcritos; a proteômica, responsável por entender as mudanças que ocorrem nas proteínas, e a metabolômica, que estuda todo o metabolismo das alterações que ocorrem em um determinado sistema quando ele é submetido a diferentes tipos de estímulos. A metabolômica é a ciência que estuda os metabólitos endógenos e exógenos em sistemas biológicos, visando fornecer informações comparativas quantitativas ou semiquantitativas sobre todos os metabólitos do sistema. Esta revisão teve como objetivo descrever as principais aplicações da ciência metabolômica na oftalmologia. Trata-se de revisão narrativa desenvolvida por um grupo de pesquisa da Universidade Federal de São Paulo, em São Paulo (SP). Buscaram-se, na literatura, as principais aplicações da ciência metabolômica em oftalmologia, utilizando as bases de dados Medline® e Lilacs, com as palavras-chave "metabolomics" e "oftalmologia", de 1º de janeiro de 2009 a 5 de abril de 2021. Foram recuperadas 216 referências, das quais 58 foram consideradas elegíveis para revisão intensiva e análise crítica. O estudo do metaboloma permite um melhor entendimento do metabolismo dos tecidos oculares. Os resultados são importantes para auxiliar no diagnóstico e como preditores da progressão de muitas doenças oculares e sistêmicas.

Artificial gait in complete spinal cord injured subjects: how to assess clinical performance / Marcha artificial em indivíduos com lesão medular completa: como avaliar desempenho clínico

Objective Adapt the 6 minutes walking test (6MWT) to artificial gait in complete spinal cord injured (SCI) patients aided by neuromuscular electrical stimulation. Method Nine male individuals with paraplegia (AIS A) participated in this study. Lesion levels varied between T4 and T12 and time post injured from 4 to 13 years. Patients performed 6MWT 1 and 6MWT 2. They used neuromuscular electrical stimulation, and were aided by a walker. The differences between two 6MWT were assessed by using a paired t test. Multiple r-squared was also calculated. Results The 6MWT 1 and 6MWT 2 were not statistically different for heart rate, distance, mean speed and blood pressure. Multiple r-squared (r2 = 0.96) explained 96% of the variation in the distance walked. Conclusion The use of 6MWT in artificial gait towards assessing exercise walking capacity is reproducible and easy to apply. It can be used to assess SCI artificial gait clinical performance. .

Objetivo Adaptar o teste de caminhada dos 6 minutos (TC6) para marcha artificial de pacientes com lesão medular completa associado a eletroestimulação neuromuscular. Método Nove participantes do sexo masculino com paraplegia (AIS A) participaram do estudo. O nível de lesão variou entre T4 e T12 , tempo de lesão variou entre 4 e 13 anos. Os pacientes realizaram dois TC6 (TC6-1 e TC6-2). Os participantes usaram eletroestimulação neuromuscular e foram auxiliados por andador. As diferenças entre os dois TC6 foram avaliadas pelo teste t pareado e calculado o r2. Resultados Não foi encontrada diferença estatística entre TC6-1 e TC6-2 para frequência cardíaca, distância, velocidade média e pressão arterial. O r2 = 0,96 explica 96% da variação na distância caminhada. Conclusão O uso do TC6 em marcha artificial para avaliação da capacidade de exercício de caminhada é reprodutível e fácil de aplicar. Esse teste pode ser utilizado para avaliar o desempenho clínico da marcha artificial de indivíduos com lesão medular. .

Brimonidine tartrate effect on retinal spreading depression depends on Müller cells / O efeito do tartarato de brimonidina sobre a depressão alastrante retiniana depende das células de Müller

Objective: Demonstrate the Brimonidine effect over Retinal Spreading Depression (SD). Brimonidine is an alpha-2–adrenergic receptor agonist, used in the management of glaucoma. Alpha2-agonists have been shown to be neuroprotective in various experimental models, however the molecular and cellular targets leading to these actions are still poorly defined. The SD of neuronal electric activity is a wave of cellular massive sustained depolarization that damages the nervous tissue. Local trauma, pressure, ischemic injuries and other chemical agents as high extracellular potassium concentration or glutamate, can trigger SD, leading to exaggerated focal electrical followed by an electrical silence. Methods: Using chicken retina as model, we performed alpha2-receptor detection by Western Blotting and Immunohistochemistry. After that we obtained electrical signals of SD by microelectrodes on retina in the absence or presence of Brimonidine. For in vivo visualization we observed retina with optical coherence tomography on normal state, with SD passing, and with SD + Brimonidine. Results: Our data demonstrated that: (1) alpha2-adrenergic receptors are present in Müller cells, (2) the treatment with Brimonidine decreases the SD‘s velocity as well as the voltage of SD waves and (3) OCT revealed that SD creates a hyper reflectance at inner plexiform layer, but on retinal treatment with brimonidine, SD was not visualized. Conclusions: Our study about brimonidine possible pathways of neuroprotection we observed it reduces SD (a neuronal damage wave), identified a new cellular target – the Müller cells, as well as, firstly demonstrated SD on OCT, showing that the inner plexiform layer is the main optically affected layer on SD. .

Objetivo: Demonstrar o efeito do Tartarato de Brimonidina, um alfa2-agonista usado no manejo do glaucoma, sobre a depressão alastrante (DA) retiniana. Esses agonistas têm demonstrado ser neuroprotetores em vários modelos experimentais, contudo seus alvos celulares e moleculares continuam indefinidos. A DA da atividade elétrica neuronal é uma onda de despolarização celular massiva e sustentada que leva ao dano no tecido nervoso. Trauma local, pressão, isquemia e outros agentes químicos como o aumento do potássio extracelular e o glutamato podem disparar a DA, levando a uma atividade elétrica exagerada seguida de silêncio elétrico. Métodos: Usando a retina de pinto como modelo, realizamos a detecção do alfa2-receptor por Western Blotting e ensaio Imunohistoquímico. Após isso, obtivemos os sinais elétricos da DA através de microeletrodos inseridos na retina durante sua passagem na presença ou ausência de Brimonidina. Para visualização do tecido utilizamos o tomógrafo de coerência optica (OCT), analisando como é a retina no seu estado de repouso, durante a passagem da DA, e a DA + brimonidina. Resultados: Nossos dados demonstraram que: (1) os receptores alfa adrenérgicos presentes na retina são do subtipo-2A e estão localizados nas células de Müller; (2) o tratamento com Brimonidina diminui a velocidade e a voltagem da onda de DA; (3) A OCT demonstrou que a DA retiniana possui um sinal óptico de maior reflectância na camada plexiforme interna, fato não observado quando foi associada à Brimonidina. Conclusão: A Brimonidina foi capaz de reduzir a DA (uma onda de lesão neuronal) e identificamos um novo possível alvo celular – a célula de Müller e demonstramos pela primeira vez uma OCT da DA, visualizando a camada plexiforme interna como a mais afetada opticamente pelo fenômeno. .

Aumento da imunorreatividade da molécula de adesão intercelular-1 na esclera e coroide em modelo experimental de hipercolesterolemia / Increased intercellular adhesion molecule-1 immunoreactivity in the sclera-choroid complex in hypercholesterolemia experimental model

Objetivo: O objetivo deste trabalho é avaliar a expressão da molécula de adesão intercelular-1 (ICAM-1) na esclera e coroide de coelhos hipercolesterolêmicos. Métodos: Coelhos New Zealand foram organizados em dois grupos: GN (grupo dieta normal), composto por 8 coelhos (8 olhos), recebeu ração padrão para coelhos, durante 4 semanas; GH (grupo hipercolesterolêmico), composto por 13 coelhos (13 olhos), recebeu dieta rica em colesterol a 1% por 8 semanas. Foi realizada a dosagem sérica de colesterol total, triglicerídeos, HDL colesterol, glicemia de jejum no início do experimento e no momento da eutanásia. Ao final da 4ª semana para o GN e 8ª semana para o GH foi realizada a eutanásia dos animais. Os olhos foram corados com hematoxilina-eosina e submetidos à análise histológica, histomorfométrica e imunohistoquímica com o anticorpo ICAM-1. Resultados: Observou-se significativo aumento do colesterol total e triglicerídeos do GH em relação ao GN (p<0,001). A avaliação histológica com hematoxilina eosina revelou grande quantidade de macrófagos no complexo esclero-coroidal do GH. No GH constatou-se significativo aumento da espessura da esclera e coroide em relação ao GN (p<0,001). Houve significativo aumento da expressão da ICAM-1 na esclera e coroide dos animais do GH em relação ao GN (p<0,001). Conclusão: Este estudo demonstra que a dieta hipercolesterolêmica induz ao aumento da expressão da ICAM-1 na esclera e coroide de coelhos. .

Objective: The aim of this study is to investigate the expression of the intercellular adhesion molecule 1 (ICAM-1) in the sclera and choroid of hypercholesterolemic rabbits Methods: New Zealand rabbits were divided into two groups: the normal diet group (NG), with 8 rabbits (8 eyes), was fed a standard rabbit diet for 4 weeks; the hypercholesterolemic group (HG), with 13 rabbits (13 eyes), was fed a 1% cholesterol- enriched diet for 8 weeks. Total serum cholesterol, triglyceride, HDL cholesterol and fasting blood glucose exams were performed at the start of the experiment and at the euthanasia time. HG and NG animals were euthanized after 8th week and 4th week, respectively. Their eyes were stained with hematoxylin-eosin and underwent histological, histomorphometric and immunohistochemical analyses with ICAM-1 antibody. Results: The diet has induced a significant increase in total cholesterol and triglyceride levels in HG when compared with NG (p<0.001). The histological analysis with hematoxylin-eosin revealed a large number of macrophages in the HG sclera-choroid complex. Moreover, a significant increase in the HG sclera and choroid thickness was observed in relation to NG (p<0.001). There was a significant increase in the ICAM-1 expression in HG sclera and choroid in relation to NG Conclusion: This study has revealed that the hypercholesterolemic diet induces an increase in the ICAM-1 expression in the rabbits’ sclera and choroid. .

Plasticity and reprogramming of differentiated ocular tissue of tadpoles of the frog, Euphlyctis cyanophlyctis under the influence of vitamin A.

Present study has shown that differentiated cell types may loose their definitive characteristics and acquire features of another specialized cell type. Young (3 toe stage) and mature (5 toe stage) tadpoles of the frog, Euphylictis cyanophlyctis were employed as experimental animals. Experiments were completed in two phases: in the first part of experiment, lenses were extracted from right eye balls of tadpoles and treated with vitamin A; in the second part of the experiment, meshed lentectomized eye ball tissues were implanted into the pit made on mid lateral position of the tail of young and mature tadpoles and were treated with vitamin A. The results obtained gave clear evidence of plasticity and reprogramming of terminally differentiated ocular tissue into lens, retina and even complete eye. Vitamin A was found to be good model for accelerating the reprogramming of differentiated ocular tissue in anuran frog tadpoles.

Chlorogenic Acid Decreases Retinal Vascular Hyperpermeability in Diabetic Rat Model

To evaluate the effect of chlorogenic acid (CGA), a polyphenol abundant in coffee, on retinal vascular leakage in the rat model of diabetic retinopathy, Sprague-Dawley rats were divided into four groups: controls, streptozotocin-induced diabetic rats, and diabetic rats treated with 10 and 20 mg/kg chlorogenic acid intraperitoneally daily for 14 days, respectively. Blood-retinal barrier (BRB) breakdown was evaluated using FITC-dextran. Vascular endothelial growth factor (VEGF) distribution and expression level was evaluated with immunohistochemistry and Western blot analysis. Expression of tight junction proteins, occludin and claudin-5, and zonula occludens protein, ZO-1 was also evaluated with immunohistochemistry and Western blot analysis. BRB breakdown and increased vascular leakage was found in diabetic rats, with increased VEGF expression and down-regulation of occludin, claudin-5, and ZO-1. CGA treatment effectively preserved the expression of occludin, and decreased VEGF levels, leading to less BRB breakdown and less vascular leakage. CGA may have a preventive role in BRB breakdown in diabetic retinopathy by preserving tight junction protein levels and low VEGF levels.

Triamcinolone Acetonide Prevents Enhancement of Hypoxia-induced Neuronal and Inducible Nitric Oxide Synthases in the Retinas of Rats with Oxygen-induced Retinopathy

PURPOSE: We investigated whether oxygen-induced retinopathy (OIR) results in changes in the protein expression of neuronal and inducible nitric oxide synthases (nNOS and iNOS, respectively) in rat model of OIR. In addition, we evaluated whether treatment of rats with triamcinolone acetonide (TA) prevents this response. METHODS: To promote OIR, Sprague-Dawley rats were exposed to hyperoxia from postnatal day 2 (P2) to P14. They were then returned to normoxia after P15. TA was injected into the right vitreous of P15 rats, while saline was injected into the left vitreous. At P18 the expression of nNOS and iNOS was determined using Western blotting and immunostaining techniques in retinas obtained from control rats. RESULTS: In P18 OIR rats, the abundance of nNOS and iNOS protein was significantly increased compared with controls. These increases were not observed in the retinas of rats treated with TA. The change in expression of nNOS and iNOS were specific to parvalbumin and glial fibrillary acidic protein-positive cells. Treatment with TA prevented the increased expression of nNOS and iNOS in all samples. CONCLUSIONS: Hypoxia upregulates expression of nNOS and iNOS in OIR rat retinas, which is can be prevented by treatment with TA.

Intravitreal bevacizumab (avastin) for circumscribed choroidal hemangioma.

Circumscribed choroidal hemangiomas are rare ophthalmic entities that cause diminution in vision due to accumulation of subretinal and/or intraretinal fluid in the macular area. Various treatment options ranging from conventional laser to photodynamic therapy have been employed to destroy the tumor and reduce the exudation; however, either the inability to penetrate through the exudative fluid or the collateral retinal damage induced by these treatment modalities make them unsuitable for lesions within the macula. We evaluated the role of intravitreal bevacizumab, a pan-vascular endothelial growth factor (VEGF) inhibitor, in reducing the sub- and intraretinal fluid in three patients with circumscribed choroidal hemangiomas. All the patients had complete resolution of the serous retinal detachment that was maintained till at least 12 months after the first injection. Intravitreal bevacizumab may be used in combination with thermal laser or photodynamic therapy in treating circumscribed choroidal hemangiomas with subretinal fluid.

Subretinal lipid exudation associated with untreated choroidal melanoma.

Subretinal lipid exudation in an untreated choroidal melanoma is very rare. It is seen following plaque radiotherapy in choroidal melanoma. There is only one case report of untreated choroidal melanoma with massive lipid exudation in a patient with metastatic hypernephroma. We report here a rare case of untreated choroidal melanoma with lipid exudation. Subretinal exudation that is rarely seen following plaque brachytherapy was noted at the borders of this untreated tumor. Lipid exudation partially resolved following brachytherapy.

Retinal nitric oxide and malonyldialdehyde levels following photodynamic therapy.

Background: To determine the retinal nitric oxide (NO) and malonyldialdehyde (MDA) levels following photodynamic therapy (PDT). Materials and Methods: Seven Dutch-belted rabbits received dextrose, while seven others received 2 mg/kg verteporfin infusion over a period of 15 minutes in a dim-lit room. Irradiation to a 1.5 mm diameter intact chorioretinal area in the right eye of verteporfin-infused rabbits, was started 5 minutes after the end of infusion. Three groups were control (dextrose infusion), infusion with verteporfin (left eyes were not irradiated), and irradiation after verteporfin injection (right eyes were irradiated). On the fifth day of the experiment, the eyes were enucleated. The retinas were subsequently frozen and homogenized. Nitrite, a stable end-product of NO and MDA, was measured using the spectrophotometer. Protein concentrations were measured by the Lowry method. Tissue NO and MDA levels were expressed as μmol/gprt and nmol/mgprt, respectively. Results: The mean retinal NO and MDA levels of the control, infusion, and irradiation groups were 24.67 ± 6.66, 0.11 ± 0.02; 45.90 ± 15.52, 0.21 ± 0.09; and 84.43 ± 14.96 μmol/gprt, 0.58 ± 0.14 nmol/mgprt, respectively. The mean retinal NO levels were significantly elevated in the infusion and irradiation groups compared with the control group (P:0.004; P:0.001). The mean retinal MDA levels were significantly elevated in the infusion and irradiation groups compared to the control one (P:0.026; P:0.001). Also the mean retinal NO and MDA levels in the irradiation group were found to be significantly higher than the infusion group (P:0.018; P:0.018). Conclusion: Not only PDT, but also verteporfin infusion alone resulted in NO and MDA level increments in the retina, which might be toxic.

Gene Expression Changes in a Rat Model of Oxygen-Induced Retinopathy

PURPOSE: To identify altered patterns of retinal mRNA expression in a rat model of oxygen-induced retinopathy (OIR). METHODS: Sprague-Dawley rats from P2 to P14 were exposed to hyperoxia (80% oxygen) to induce OIR and then returned to normoxic conditions. Control rats were sustained in room air. Retinal gene expression between the rats of OIR and the controls was compared using cDNA microarray analysis. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to verify the microarray results. RESULTS: Among a total of 12,731 cDNAs analyzed by mircroarray, 13 genes were strongly up- or down-regulated (>2-fold change over controls) in the OIR rats. We found a significant increase in expression of 10 genes (CaM-kinase II inhibitor; acidic nuclear phosphoprotein 32 family, member A; vascular endothelial growth factor; interferon alpha-inducible protein 27-like; similar to enthoprotin, epsin 4, clathrin interacting protein; nidogen [entactin]; tubulin, beta5; fibrillin-1; spectrin beta2; and stearoyl-coenzyme A desaturase 2) and a significant decrease in expression of 3 genes (myelin-associated oligodendrocytic basic protein, heat shock protein, and decorin) in OIR rats compared to controls. CONCLUSIONS: We confirmed changes in expressions of various retinal genes in a rat model of OIR by microarray and RT-PCR. This study should contribute to the understanding of genetic indicators associeated with OIR.

DNA degradation of porcine retinal cells for estimation of postmortem interval / 法医学杂志

OBJECTIVE@#To investigate DNA degradation of porcine retinal cells by single cell gel electrophoresis (SCGE) for estimation of postmortem interval (PMI).@*METHODS@#Degradation of retinal cells was observed by SCGE at 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24h after death respectively, under the environmental conditions of being kept in dark place as well as a controlled temperature of (15 +/- 2) degrees C and humidity of (50 +/- 5)%. The comet pictures were captured by fluorescence microscope and analyzed by single cell gel electrophoresis (IMI 1.0).@*RESULTS@#From 2h to 24h postmortem, the degree of degradation of retinal DNA increased with the prolongation of PMI. The postmortem regression functions of head DNA%, L(T)/L(H), I(T)/I(H) were y = 92.227-5.188 x + 0.019 x2 + 0.001 x3 (R2 = 0.971), y = 0.035e(0.191x) (R2 = 0.947), y = 0.099e(0.264x) (R2 = 0.955), respectively.@*CONCLUSION@#The examination of retinal cell DNA degradation by SCGE is useful for estimating PMI.

Differential Expression of Stem Cell Markers and Vascular Endothelial Growth Factor in Human Retinoblastoma Tissue

PURPOSE: To investigate the relationship between vascular endothelial growth factor (VEGF) and the cancer stem cell-vascular niche complex in human retinoblastoma tissue. METHODS: Six human retinoblastoma specimens primarily enucleated for Reese-Ellsworth classification stage 5a were stained to detect cancer stem cell markers, including ABCG2 for the stem cell marker and MCM2 for the neural stem cell marker, as well as to detect VEGF for the angiogenic cytokine. Using immunofluorescence, the expression of these proteins was analyzed, and their relative locations noted. RESULTS: In non-neoplastic retina of tumor-bearing eyes, ABCG2 and MCM2 were sporadically expressed in the ganglion cell layer and the inner nuclear layer, whereas VEGF was sporadically expressed in inner retina where retinal vessels are abundantly distributed. In the tumor, ABCG2 was strongly expressed out of Wintersteiner rosettes, whereas MCM2 and VEGF were strongly stained in the rosettes. Interestingly, the outer portion of the rosettes was positive for MCM2, and the inner portion of the rosettes was positive for VEGF. CONCLUSIONS: Our data demonstrated that MCM2 and VEGF are strongly expressed in the rosettes of the tumor, which were far from the area of ABCG2-positive cells. Although VEGF might not directly contribute to the cancer stem cell-vascular niche complex, it could play some role in the differentiation of tumor cells to build up the rosettes.

Evaluation of early abnormalities of the sensory retina in a hypercholesterolemia experimental model: an immunohistochemical study / Avaliação das anormalidades precoces da retina sensorial em modelo experimental de hipercolesterolemia: estudo imunohistoquímico

PURPOSE: The aim of this study is to demonstrate the early changes of the sensory retina induced by hypercholesterolemia in an experimental model. METHODS: New Zealand rabbits were divided into two groups: CG (Control Group) was fed a normal diet for 6 weeks. G1 was initially fed a 1 percent cholesterol diet for two weeks and from the 14th day on a 0.5 percent cholesterol diet until the 42nd day. The eyes underwent an immunohistochemical analysis with monoclonal antibodies anti-calretinin and anti-glial fibrillary acidic protein (GFAP). RESULTS: G1 cells and cell elements presented significant immunoreactivity to anti-calretinin. No immunoreactivity to anti-glial fibrillary acidic protein was observed in both groups. CONCLUSION: This study has shown that a hypercholesterolemic diet may induce early changes in the sensory retina in rabbits. The anti-calretinin monoclonal antibody was able to reveal calcium accumulation inside the nerve cells.

OBJETIVO: O objetivo deste estudo é demonstrar experimentalmente as alterações precoces da retina sensorial induzidas pela hipercolesterolemia. MÉTODOS: Coelhos New Zealand foram organizados em dois grupos: GC (grupo controle), composto por 6 coelhos (6 olhos), recebeu dieta normal por 6 semanas; G1, composto por 12 coelhos (12 olhos), tratado previamente com ração colesterol a 1 por cento (Sigma-Aldrich) por 2 semanas e a partir do 14º dia com ração colesterol a 0,5 por cento (Sigma-Aldrich). Os olhos foram submetidos à análise imunohistoquímica com os anticorpos monoclonais anticalretinina e anti-glial fibrillary acidic protein (GFAP). RESULTADOS: G1 apresentou maior número de células e elementos celulares imunoreativos a anticalretinina que o GC, com relevância estatística. GFAP foi negativo em ambos os grupos. CONCLUSÃO: Este estudo demonstrou que a dieta hipercolesterolêmica pode induzir alterações precoces na retina sensorial em coelhos. O anticorpo monoclonal anticalretinina foi capaz de revelar o acúmulo de cálcio dentro das células neuronais retiniana.

Gene expression profiling of light-induced retinal degeneration in phototransduction gene knockout mice

Exposure to light can induce photoreceptor cell death and exacerbate retinal degeneration. In this study, mice with genetic knockout of several genes, including rhodopsin kinase (Rhok-/-), arrestin (Sag-/-), transducin (Gnat1-/-), c-Fos (c-Fos-/-) and arrestin/transducin (Sag-/-/Gnat1-/-), were examined. We measured the expression levels of thousands of genes in order to investigate their roles in phototransduction signaling in light-induced retinal degeneration using DNA microarray technology and then further explored the gene network using pathway analysis tools. Several cascades of gene components were induced or inhibited as a result of corresponding gene knockout under specific light conditions. Transducin deletion blocked the apoptotic signaling induced by exposure to low light conditions, and it did not require c-Fos/AP-1. Deletion of c-Fos blocked the apoptotic signaling induced by exposure to high intensity light. In the present study, we identified many gene transcripts that are essential for the initiation of light-induced rod degeneration and proposed several important networks that are involved in pro- and anti-apoptotic signaling. We also demonstrated the different cascades of gene components that participate in apoptotic signaling under specific light conditions.

Distribution of caveolin isoforms in the lemur retina

The distribution of caveolin isoforms was previouslyevaluated in the retinas of different species, but has notyet been described in the primate retina. In this study, thedistribution of caveolins was assessed via immunochemistryusing isoform-specific antibodies in the retina of the black-and-white ruffed lemur. Here, we report the presence of avariety of caveolin isoforms in many layers of the lemurretina. As normal human retinas were not available forresearch and the retinas of primates are fairly similar tothose of humans, the lemur retina can be utilized as amodel for caveolin distribution in normal humans.

Direct Detection of Reactive Nitrogen Species in Experimental Autoimmune Uveitis

PURPOSE: Demonstrate unequivocally the generation of nitric oxide in experimental autoimmune uveoretinitis by electron spin resonance spectroscopy (ESR) using ferrous iron complex of N-methyl-D-glucamine dithiocarbamate, (MGD)2-Fe2+, as a spin trap. METHODS: Experimental autoimmune uveitis was induced in Lewis rats, and at the peak of the intraocular inflammation, the animals received intravitreous injections of the spin trap. The retina and choroid dissected from the enucleated globes were subjected to ESR. Similarly, the retina and choroid obtained at the peak of experimental autoimmune uveo-retinitis (EAU) were placed in a vial containing luminal, and chemiluminescence was counted on a Packard liquid scintillation analyzer. RESULTS: The ESR three-line spectrum (g=2.04; a(N)=12.5 G) obtained was characteristic of the adduct [(MGD)2-Fe2+-NO]. The majority of this signal was eliminated by the inducible nitric oxide synthase (iNOS) specific inhibitor aminoguanidine injected inflamed retina was detected when compared with that of the non inflamed controls. The chemiluminescent activity was further increased two-fold by the addition of bicarbonate to the inflamed retina; the phenomenon is attributable only to the presence of a high steady-state concentration of peroxynitrite. CONCLUSIONS: The study shows an unequivocal presence of nitric oxide in EAU retina and choroid and the generation of peroxynitrite. High levels of these reactive nitrogen species generated in the inflamed retina and choroids are certain to cause irreversible tissue damage, especially at the susceptible sites such as photoreceptors.

Effect of shRNA inhibiting HiF1alpha gene on TIMP1 expression in RPE cells / 华中科技大学学报（医学）（英德文版）

Small hairpin RNA (shRNA) was used to silence the HIF1alpha gene in human retinal pigment epithelial cells (RPE) under hypoxia in order to observe the effect of gene silencing on the expression of matrix metalloproteinase tissue inhibitor 1 (TIMP1). By using chemical hypoxic inducer CoCl2, to mimic RPE hypoxic environment, shRNA against the targeting region of HIF1alpha mRNA sequence was synthesized by a method of in vitro transcription, and the HIF1alpha was interfered in RPE cultured under hypoxia (induced by 150 micromol/L CoCl2). RT-PCR was employed to detect the expression of HIF1alpha and TIMP1. The expression levels of HIF1alpha and TIMP1 were measured by using Western blotting. The results showed that after the RPE were transfected with specific shRNA against HIF1alpha mRNA, RT-PCR revealed that under hypoxia, the efficacy of HIF1alpha gene silencing in RPE was 83.4%. Western blotting revealed that the expression levels of HIF1alpha protein was dramatically dropped. In addition. RT-PCR results demonstrated that the expression of TIMP1 mRNA was decreased by 28.9%, and the expression levels of TIMP1 protein were also significantly reduced by Western blotting. It was suggested that shRNA targeted against HIF1alpha mRNA could effectively silence the HIF1alpha gene, subsequently effectively inhibit the hypoxia-induced up-regulation of TIMP1.