Short Term Visual Prognosis After Retinal Laser Photocoagulation for Diabetic Retinopathy.

To assess the outcome of laser photocoagulation treatment for diabetic retinopathy in relation to various risk factors. Method: The change in visual acuity shortly after laser photocoagulation for diabetic retinopathy was assessed in 50 eyes of 25 patients and was compared to the age of onset of diabetes, type of retinopathy, pre treatment duration of diabetes, hypertension, microalbuminuria, smoking, dyslipedemia, associated complications of diabetes and type of treatment of diabetes. Results: Visual improvement was good in young diabetics, short duration of diabetes and parents having mild diabetic retinopathy. Factors having adverse effect on prognosis were longer duration of diabetes, hypertension, dyslipedemia, nephropathy and severe diabetic retinopathy. There was no significant influence of smoking, glycemic control, type of treatment, age of onset and sex of patients on visual outcome. Conclusion: Early diagnosis of retinopathy and initiation of specific treatment by laser photocoagulation at earlier stages with proper control of risk factors viz hypertension, dyslipidemia and nephropathy lead to a favourable visual outcome.

Light-induced retinal injury enhanced neurotrophins secretion and neurotrophic effect of mesenchymal stem cells in vitro / Lesão de retina induzida por luz aumentou a secreção de neurotrofinas e o efeito neurotrófico das células primordiais mesenquimais in vitro

PURPOSE: To investigate neurotrophins expression and neurotrophic effect change in mesenchymal stem cells (MSCs) under different types of stimulation. METHODS: Rats were exposed in 10,000 lux white light to develop light-induced retinal injury. Supernatants of homogenized retina (SHR), either from normal or light-injured retina, were used to stimulate MSCs. Quantitative real time for polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) were conducted for analysis the expression change in basic fibroblast growth factor (bFGF), brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) in MSCs after stimulation. Conditioned medium from SHR-stimulated MSCs and control MSCs were collected for evaluation their effect on retinal explants. RESULTS: Supernatants of homogenized retina from light-injured rats significantly promoted neurotrophins secretion from MSCs (p<0.01). Conditioned medium from mesenchymal stem cells stimulated by light-injured SHR significantly reduced DNA fragmentation (p<0.01), up-regulated bcl-2 (p<0.01) and down-regulated bax (p<0.01) in retinal explants, displaying enhanced protective effect. CONCLUSIONS: Light-induced retinal injury is able to enhance neurotrophins secretion from mesenchymal stem cells and promote the neurotrophic effect of mesenchymal stem cells.

OBJETIVO: Investigar a expressão de neurotrofinas e mudança no efeito neurotrófico de células-tronco mesenquimais (MSCs) sob diferentes tipos de estimulação. MÉTODOS: Os ratos foram expostos em 10.000 lux de luz branca para desenvolver a lesão da retina induzida por luz. Os sobrenadantes de homogeneizado de retina (SHR) quer a partir de retina normal ou da lesada por luz, foram usados para estimular as células-tronco mesenquimais. O RT-PCR quantitativa e ELISA foram realizados para análise da alteração de expressão do fator básico de crescimento de fibroblastos (bFGF), do fator neurotrófico derivado do cérebro (BDNF) e do fator neurotrófico ciliar (CNTF) em MSCs após a estimulação. O meio condicionado de células-tronco mesenquimais estimuladas por SHR e controles foram coletadas para avaliação de seu efeito sobre os explantes de retina. RESULTADOS: SHR de retinas de rato lesadas por luz promoveram aumento significativo de secreção de neurotrofinas em MSCs (p<0,01). O meio condicionado de SHR lesado por luz reduziu significativamente a fragmentação do DNA de MSCs (p<0,01), elevação de Bcl-2 (p<0,01) e redução de bax (p<0,01) em explantes de retina, mostrando um aumento do efeito protetor. CONCLUSÕES: A lesão da retina induzidos pela luz é capaz de aumentar a secreção de neurotrofinas e promover o efeito neurotrófico de células-tronco mesenquimais.

Solar retinopathy without abnormal exposure: case report / Retinopatia solar sem exposição anormal: relato de caso

Solar retinopathy is photochemical damage to the retina, usually caused, by direct or indirect solar observation resulting from the use of hallucinogenic drugs, mental disorders or during eclipses. There may be a loss of visual acuity. We report the case of a 38-year-old patient who presented with a clinical diagnosis of solar retinopathy in the left eye, no prior history of sun exposure, normal visual acuity and complaints of metamorphopsia. Optical coherence tomography showed a rupture of the retinal pigment epithelium, confirming class II solar retinopathy. Visual acuity tends to normalize after 3 to 9 months, but not always. Thus, there is a real need to educate people about using eye protection during sun exposure especially given that some people may be highly susceptible to retinal damage, which was presumably the case for this patient. Finally, we note the importance of optical coherence tomography in diagnosing solar retinopathy.

Retinopatia solar é o dano fotoquímico à retina causado, geralmente, pela observação solar, direta ou indireta, devido ao uso de drogas alucinógenas, distúrbios psíquicos ou durante eclipses. Pode haver, ou não, perda de acuidade visual. Relata-se o caso de uma paciente, 38 anos, com quadro de retinopatia solar em olho esquerdo, sem história prévia de exposição solar, apresentando acuidade visual normal e queixa de metamorfopsia. A tomografia de coerência óptica mostrou ruptura do epitélio pigmentar da retina, confirmando retinopatia solar padrão II. A acuidade visual tende a normalizar-se entre 3 a 9 meses, mas nem sempre. Assim, enfatiza-se a necessidade de orientação à população sobre proteção ocular durante exposição solar pela possibilidade de existirem pessoas com susceptibilidade elevada ao dano retiniano, como se presume possa ter ocorrido com esta paciente. Finalmente, destaca-se a importância da tomografia de coerência óptica para o diagnóstico da retinopatia solar.

Retinal incorporation and differentiation of mesenchymal stem cells intravitreally injected in the injured retina of rats / Incorporação e diferenciação retiniana de células tronco mesenquimais intravítreas em ratos

PURPOSE: To evaluate the pattern of retinal integration and differentiation of mesenchymal stem cells (MSCs) injected into the vitreous cavity of rat eyes with retinal injury. METHODS: Adult rat retinas were submitted to laser damage followed by transplantation of DAPI-labeled BM-MSCs grafts. To assess the integration and differentiation of BM-MSCs in laser-injured retina, host retinas were evaluated 2.4 and 8 weeks after injury/transplantation. RESULTS: Our results demonstrated that the grafted cells survived in the retina for at least 8 weeks and almost all BM-MSCs migrated and incorporated into the neural retina, specifically in the outer nuclear layer (ONL), inner nuclear layer (INL) and ganglion cell layer (GCL) while a subset of grafted cells were found in the subretinal space posttransplantation. At 8 weeks immunohistochemical analysis with several retinal specific markers revealed that the majority of the grafted cells expressed rhodopsin, a rod photoreceptor marker, followed by parvalbumin, a marker for bipolar and amacrine cells. A few subsets of cells were able to express a glial marker, glial fibrillary acidic protein. However, grafted cells failed to express pan-cytokeratin, a retinal pigment epithelium marker. CONCLUSIONS: These results suggest the potential of BM-MSCs to differentiate into retinal neurons. Taken together, these findings might be clinically relevant for future mesenchymal stem cell therapy studies concerning retinal degeneration repair.

OBJETIVO: Avaliar o padrão de integração e diferenciação retiniana de células tronco mesenquimais (CTM) injetadas na cavidade vítrea de ratos portadores de lesões retinianas. MÉTODOS: Ratos Wistar adultos foram submetidos a múltiplas lesões retinianas utilizando-se YAG laser e injeção intravítrea de células tronco mesenquimais. A fim de se avaliar a integração e diferenciação retiniana, o tecido retiniano lesado pelo YAG laser / tratado pelas células tronco, foi avaliado 2, 4 e 8 semanas após a lesão. RESULTADOS: As células injetadas na cavidade vítrea sobreviveram na retina por pelo menos 8 semanas e quase todas células tronco mesenquimais migraram e incorporaram-se na retina neural, especificamente nas camadas nucleares externa e interna e camada de células ganglionares. Uma pequena quantidade de células foi encontrada no espaço sub-retiniano. A análise imuno-histoquímica de 8 semanas mostrou que a maioria das células injetadas expressou rodopsina (marcador para fotorreceptores), parvalbumina (marcador para células bipolares e amácrinas), GFAP (marcador de células gliais). As células injetadas não expressaram a pancitoqueratina, que é a marcadora de células do epitélio pigmentar da retina. CONCLUSÕES: Ocorre aparente diferenciação e incorporação de células tronco mesenquimais na retina de ratos após injeção intravitrea destas células.

Estudo experimental da aplicação retiniana do laser infravermelho via transescleral sob condições de baixa visibilidade / Transscleral infrared laser retinal photocoagulation experimental study under low visibility conditions

OBJETIVOS: Pesquisa experimental, com laser de diodo infravermelho, para estimar a segurança, a reprodutibilidade e a permeabilidade da parede ocular à sua atuação clínica, quando aplicado via transescleral, em condições de baixa visibilidade. MÉTODOS: Submetemos olhos de coelhos pigmentados da raça Nova Zelândia à fotocoagulação retiniana por laser de diodo infravermelho. No olho direito, realizamos fotocoagulação via transescleral sob parâmetros de potência e tempo pré-determinados clinicamente. No olho esquerdo, foram repetidos os mesmos valores da potência e tempo usados no olho direito, desta vez, via transpupilar. Imediatamente e após 2 meses, estudos clínicos baseados na retinografia e histopatológicos foram realizados. RESULTADOS: A permeabilidade da parede ocular, quando da aplicação do laser de diodo infravermelho via transescleral, variou entre 58,95 e 63,87 por cento. A média da permeabilidade da parede ocular a 300 mW (63,14 por cento) mostrou-se significativamente superior àquela da permeabilidade da parede ocular encontrada a 500 mW (59,11 por cento), (P<0,05). CONCLUSÕES: Este estudo sugere a existência da relação dose-resposta em relação aos parâmetros empregados na aplicação do laser de diodo infravermelho via transescleral, com permeabilidade da parede ocular mensurável e reprodutível. Nenhuma rotura, hemorragia ou descolamento da retina ou vítreo foi constatado aos exames subseqüentes às aplicações do laser de diodo infravermelho, o que torna o uso da fotocoagulação via transescleral, no modelo experimental, seguro, mesmo sob condições de baixa visibilidade dos meios.

PURPOSE: Retinal photocoagulation under poor visualization condition is often required. Transscleral infrared laser can be used as an alternative to regular transpupillary treatment. Based upon retinographic measurements, we proposed to estimate the reproducibility as well as ocular wall permeability rate for this treatment. Our primary goal was to evaluate whether this technique can deliver adequate photocoagulation at predetermined parameters without direct retinal visualization. METHODS: In New Zealand pigmented rabbits, optimal transscleral infrared diode laser settings were administered to the right eye. With the same parameters, transpupillary photocoagulation was repeated in the left eye. Retinographic and clinical examinations were performed immediately and two months later. RESULTS: Ocular wall permeability rate varied between 58.95 and 63.87 percent. Average permeability using a power of 300 mW (63.14 percent) was found to be higher than that encountered before its enhancement up to 500 mW (59.11 percent), (P<0.05). CONCLUSIONS: Setting parameters showed dose-response effect. No retinal hole or retinal detachment was noticed in any rabbit. Transscleral infrared photocoagulation appeared to be a reproducible and secure method in the experimental model.

Protective Effect of Heat Shock Proteins 70.1 and 70.3 on Retinal Photic Injury after Systemic Hyperthermia

PURPOSE: This study aimed to determine the relationship between the heat shock protein 70 from hsps70.1 and 70.3 on retinal photic injury after systemic hyperthermia. METHODS: Eight-week-old female C57BL/6 mice were kept at a constant temperature of 41~42 degrees C for 25~30 minutes. After dark-adaptation for 8 hours, intense light of 11000 lux was maintained for 6 hours. Histology and immunohistochemistry for the inducible heat shock protein 70 (hsp70), the constitutive heat shock protein 70 (hsc70), and western blot analysis, reverse transcriptase-polymerase chain reaction for hsp70.1 and hsp70.3 were performed just before photic injury and after 1, 4, 7, and 14 days. RESULTS: Light-induced retinal degeneration was prevented by thermotolerance. After hyperthermia, hsp70 was densely expressed in the inner segment of the photoreceptor layer on the photic injury. Hsp70 expression increased for 4 days after photic injury and slowly decreased thereafter. mRNA from hsp70.3 was induced earlier than that of hsp70.1. CONCLUSIONS: Retinal photic injury was prevented by hyperthermia-induced hsp70. Hsp70 from hsp70.3 may be a rapid and short-lived responder, and that from hsp70.1 is a slower and more sustained responder. Hsp70 from hsp70.3 may be an initial retinal chaperone while hsp70 from hsp70.1 may be a sustained chaperone.

Estudo com tomografia de coerência óptica em pacientes com retinopatia solar / Optical coherence tomography study in patients with solar retinopathy

A retinopatia solar é uma afecção ocular que pode ocorrer quando existe observação solar (direta ou indireta) sem proteção adequada. Tradicionalmente, os casos relatados são ligados a comtemplações de eclipses solares em pacientes usuários, ou não, de alucinógenos, rituais religiosos ou distúrbios psiquícos. O achado retiniano típico se constitui em uma lesão branco amarelada localizada na região foveolar. A sua fisiopatogenia tem sido atribuída a ação do comprimento de luz azul do espectro solar (reação fotoquímica). Estudos histopatológicos demonstram a presença de alterações variáveis no epitélio pigmentado e fotorreceptores retinianos em portadores de retinopatia solar. Local: Departamento de Retina e Vítreo do serviço de Oftalmologia da Faculdade de Medicina da Universidade de São Paulo. Objetivo: Descrever dois casos de retinopatia solar aguda avaliados pelo exame de tomografia de coerência óptica (OCT). Método: Avaliação ocular clínica e tomográfica consecutiva em dois pacientes com história recente de retinopatia solar. A tomografia de coer6encia óptica é um novo exame para avaliação da retina, utiliza-se do principio de ondas coerência fazendo cortes tomográficos da retina. O modelo utilizado (OCT-1) foi derivado do protótipo descrito por Hee e colaboradores. Resaultados: Ambos os casos apresentaram história clínica e achados fundoscópicos similares. O exame com tomografia de coerência óptica não demonstrou anormalidadesda área macular em ambos os casos. Conclusão: Mesmo com poucos casos na literatura, é possível que o exame de OCT seja um indicador do prognóstico visual em casos de afecções maculares por retinopatia solar. A ausência de alterações estruturais precoces constatadas nos casos examinados pode ser justificada pelo grau leve de acometimento foveal encontrado.

Effect of the Absence of Heat Shock Protein 70.1 (hsp70.1) on Retinal Photic Injury

This study aimed to evaluate the protective effect of heat shock protein70 (hsp70) on retinal photic injuries, and to determine the relationship between hsp70s from hsp70.1 and 70.3. C57BL/6 wild type (hsp70.1+/+) and knockout type (hsp70.1-/-) mice from the same littermates were placed in light of 11000 lux for 6 hours, and were sacrificed at 1, 4, 7, and 14 days after stress. H & E staining, immunohistochemistry, and western blot analysis were performed. The hsp70.1-/- mice exhibited more disarranged and more diffusely destroyed photoreceptors than the hsp70.1+/+ mice. Hsp70 induction by light in both the hsp70.1 +/+ and hsp70.1 -/- mice peaked at 1 day after light stress. The Hsp70 level in the hsp70.1 +/+ mice reduced slowly and was almost constant for 7 days. However, in the hsp70.1 -/- mice, it decreased rapidly and returned, after 7 days, to a similar level to that prior to light exposure. According to which gene they originate from, hsp70s may play specific roles in protecting the retina against stresses. Hsp70 from the hsp70.1 gene may act as a sustained responder to retinal photic injury.

Trans-scleral and intravitreal contact ND: YAG laser application: an experimental study

A contact Nd: YAG laser with a sapphire tip [convex surface 2 mm in diameter] was used to coagulate the retina and ciliary body through the sclera. The laser energy was successfully transmitted through the sclera producing retinal coagulation and destruction of the ciliary body. A 0.2 mm in diameter sapphire tip and Nd YAG laser was used to perform transvitreal retinal coagulation, retinotomy and retinochoriodal incision. Minimal hemorrhage occurred when retinochoroidotomy was done. Probe-tissue adhesion occurred but could easily be separated. Contact application of laser energy is a modern developed technology used primarily with a sapphire tip for cutting tissue [Daikuzono et at, 1985]. Because laser incisions are commonly accompanied by coagulation, bleeding from the tissue is reduced to a minimum with this technique. The initial successful application of contact laser delivery have been reported independently by us [Peyman et al., 1987] and Ando and associates 1986. To our knowledge, no long term results of contact Nd: YAG laser on ocular tissues has been reported thus far