Methylene blue reduces IL-1β levels by enhancing ERK1/2 and AKT phosphorylation to improve diabetic retinopathy in rats / 细胞与分子免疫学杂志

Objective To investigate the neuroprotective effect of methylene blue on diabetic retinopathy in rats. Methods Thirty SD rats were randomly divided into blank, control and experimental groups. The control and experimental groups were induced with diabetes by streptozotocin (STZ) intraperitoneal injection. After 6 weeks of successful modeling, the experimental group received intravitreal injection of methylene blue at a dose of [0.2 mg/(kg.d)], while the control group received an equal amount of dimethyl sulfoxide (DMSO) intravitreal injection, both continuously injected for 7 days. ELISA was used to detect the levels of retinal superoxide dismutase (SOD), 8-iso-prostaglandin F2alpha (iPF2α) and interleukin-1β (IL-1β) in rats. Western blot analysis was used to detect the expression of retinal extracellular signal-regulated kinase 1/2 phosphorylation (p-ERK1/2) and phosphorylated protein kinase B (p-AKT), and PAS staining was used to detect retinal morphological changes. Results Compared with the blank group rats, the retinal SOD activity in the control and experimental group rats was significantly reduced. iPF2α, IL-1β and p-ERK1/2 level increased, while p-AKT level decreased. Compared with the control group, the SOD activity of the experimental group rats increased. iPF2α and IL-1β level went down, while p-ERK1/2 and p-AKT level went up significantly. The overall thickness of the retinal layer and the number of retinal ganglion cells were significantly reduced. Conclusion Methylene blue improves diabetic retinopathy in rats by reducing retinal oxidative stress and enhancing ERK1/2 and AKT phosphorylation.

Wogonoside alleviates high glucose-induced dysfunction of retinal microvascular endothelial cells and diabetic retinopathy in rats by up-regulating SIRT1 / 南方医科大学学报

OBJECTIVE@#To investigate the effects of wogonoside on high glucose-induced dysfunction of human retinal microvascular endothelial cells (hRMECs) and streptozotocin (STZ)-induced diabetic retinopathy in rats and explore the underlying molecular mechanism.@*METHODS@#HRMECs in routine culture were treated with 25 mmol/L mannitol or exposed to high glucose (30 mmol/L glucose) and treatment with 10, 20, 30, 40 μmol/L wogonoside. CCK-8 assay and Transwell assay were used to examine cell proliferation and migration, and the changes in tube formation and monolayer cell membrane permeability were tested. ROS, NO and GSH-ST kits were used to evaluate oxidative stress levels in the cells. The expressions of IL-1β and IL-6 in the cells were examined with qRT-PCR and ELISA, and the protein expressions of VEGF, HIF-1α and SIRT1 were detected using Western blotting. We also tested the effect of wogonoside on retinal injury and expressions of HIF-1α, ROS, VEGF, TNF-α, IL-1β, IL-6 and SIRT1 proteins in rat models of STZ-induced diabetic retinopathy.@*RESULTS@#High glucose exposure caused abnormal proliferation and migration, promoted angiogenesis, increased membrane permeability (P < 0.05), and induced inflammation and oxidative stress in hRMECs (P < 0.05). Wogonoside treatment concentration-dependently inhibited high glucose-induced changes in hRMECs. High glucose exposure significantly lowered the expression of SIRT1 in hRMECs, which was partially reversed by wogonoside (30 μmol/L) treatment; interference of SIRT1 obviously attenuated the inhibitory effects of wogonoside against high glucose-induced changes in proliferation, migration, angiogenesis, membrane permeability, inflammation and oxidative stress in hRMECs. In rat models of STZ-induced diabetic retinopathy, wogonoside effectively suppressed retinal thickening (P < 0.05), alleviated STZ-induced retinal injury, and increased the expression of SIRT1 in the retinal tissues (P < 0.001).@*CONCLUSION@#Wogonoside alleviates retinal damage caused by diabetic retinopathy by up-regulating SIRT1 expression.

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.

Correlation of the aqueous humor total antioxidant capacity, total oxidant status, and levels of IL-6 and VEGF with diabetic retinopathy status / Correlação entre níveis de humor aquoso da capacidade antioxidante total, estado oxidante total, IL-6, VEGF e status da retinopatia diabética

ABSTRACT Purpose: We aimed to compare the aqueous humor total oxidant status, total antioxidant capacity, and levels of interleukin-6 and vascular endothelial growth factor between patients with diabetic retinopathy and controls and to correlate these levels with the DR status. Methods: Patients who underwent cataract surgery were enrolled. The first group (control group) comprised patients without diabetes; the second group comprised diabetic patients without retinopathy; the third group comprised patients with nonproliferative diabetic retinopathy; and the fourth group comprised patients with proliferative diabetic retinopathy. All patients underwent full ophthalmologic examination before cataract surgery. Prior to surgery, samples of aqueous humor sampling were obtained and stored at -80 °C. Total antioxidant capacity, total oxidant status, and levels interleukin-6 and vascular endothelial growth factor were investigated in these samples and correlated with diabetic retinopathy status. Results: This study analyzed 86 pairs of eyes of 86 patients. All groups were statistically similar in age and sex, but the total antioxidant capacity was lowest in patients with proliferative diabetic retinopathy. Moreover, the total oxidant status and levels of vascular endothelial growth factor and interleukin-6 were found to slightly increase according to the retinopathy status. Conclusion: Oxidative stress, interleukin-6, and vascular endothelial growth factor in the aqueous humor seem to play important roles in the pathogenesis of diabetic retinopathy, especially in the proliferative type.

RESUMO Objetivo: Procurou-se comparar o humor aquoso estado oxidante total, a capacidade antioxidante total, e os níveis de interleucina-6 e do fator de crescimento endotelial vascular entre pacientes com retinopatia diabética e em indivíduos controles, e correlacionar esses níveis com o status da retinopatia diabética. Métodos: Pacientes submetidos à cirurgia de catarata foram incluídos. O primeiro grupo (grupo controle) foi composto por pacientes sem diabetes; o segundo grupo inclui pacientes dia béticos sem retinopatia; o terceiro grupo inclui pacientes com retinopatia diabética não proliferativa; e o quarto grupo inclui pacientes com retinopatia diabética proliferativa. Todos os pacientes foram submetidos a exame oftalmológico completo antes da cirurgia de catarata. Antes da cirurgia, amostras de humor aquoso foram obtidas e armazenadas a -80oC. A capacidade antioxidante total, o estado oxidante total e os níveis de interleucina-6 e fator de crescimento endotelial vascular foram investigados nessas amostras e correlacionados com o status da retinopatia diabética. Resultados: Este estudo analisou 86 pares de olhos de 86 pacientes. Todos os grupos foram estatisticamente semelhantes em idade e sexo, mas a capacidade antioxidante total foi menor em pacientes com retinopatia diabética proliferativa. Além disso, o estado oxidante total e os níveis de fator de crescimento endotelial vascular e interleucina-6 estavam ligeiramente aumentados de acordo com o status da retinopatia. Conclusão: O estresse oxidativo, a interleucina-6 e o fator de crescimento endotelial vascular no humor aquoso parecem desempenhar papel importante na patogênese da retinopatia diabética, especialmente no tipo proliferativo.

Kaempferol inhibited VEGF and PGF expression and in vitro angiogenesis of HRECs under diabetic-like environment

Diabetic retinopathy (DR) is one of the common and specific microvascular complications of diabetes. This study aimed to investigate the anti-angiogenic effect of kaempferol and explore its underlying molecular mechanisms. The mRNA expression level of vascular endothelial growth factor (VEGF) and placenta growth factor (PGF) and the concentrations of secreted VEGF and PGF were measured by qTR-PCR and ELISA assay, respectively. Human retinal endothelial cells (HRECs) proliferation, migration, and sprouting were measured by CCK-8 and transwell, scratching wound, and tube formation assays, respectively. Protein levels were determined by western blot. High glucose (25 mM) increased the mRNA expression levels of VEGF and PGF as well as the concentrations of secreted VEGF and PGF in HRECs, which can be antagonized by kaempferol (25 µM). Kaempferol (5-25 µM) significantly suppressed cell proliferation, migration, migration distance and sprouting of HRECs under high glucose condition. The anti-angiogenic effect of kaempferol was mediated via downregulating the expression of PI3K and inhibiting the activation of Erk1/2, Src, and Akt1. This study indicates that kaempferol suppressed angiogenesis of HRECs via targeting VEGF and PGF to inhibit the activation of Src-Akt1-Erk1/2 signaling pathway. The results suggest that kaempferol may be a potential drug for better management of DR.

Increased levels of vascular endothelial growth factor in the aqueous humor of patients with diabetic retinopathy.

Purpose: This study aims to investigate the levels of aqueous vascular endothelial growth factor (VEGF) in diabetic patient groups in comparison to normal subjects, and to correlate elevated VEGF with the severity of diabetic retinopathy (DR). Materials and Methods: Aqueous samples were obtained from 78 eyes of 74 patients undergoing intraocular surgery and they were examined by the enzyme-linked immunosorbent assay. Color photographs, optical coherence tomography scans, and fluorescein angiography were used to evaluate patients preoperatively. Results: A strong statistical correlation was found to exist between the level of aqueous VEGF and the severity of DR (P < 0.001), whereas, the VEGF levels in a control group and a diabetic group without DR were not significantly different (P = 0.985). Aqueous VEGF levels were significantly elevated in patients with proliferative DR (PDR) as compared to the control group (P < 0.001), to diabetic patients without retinopathy (NDR) (P < 0.001), and to diabetic patients with nonproliferative DR (NPDR) (P < 0.001). The aqueous VEGF levels were significantly higher in patients with active PDR than in those with quiescent PDR (P = 0.001). On the other hand, a statistically insignificant (P = 0.065) correlation was found between elevated aqueous VEGF and the presence of macular edema in the NPDR group. Conclusions: VEGF was elevated in the aqueous humor of patients with DR compared to that in normal eyes. The aqueous VEGF level had a strong correlation with the severity of retinopathy along with a statistically insignificant difference in macular edema.

Diabetes melito tipo 1 e gestação: [revisão] / Type 1 diabetes mellitus and pregnancy: [review]

As gestações em mulheres com diabetes têm apresentado resultados que melhoraram dramaticamente nas últimas décadas, em razão dos progressos com a monitorização das glicemias e administração de insulina. A gravidez nas mulheres com diabetes tipo 1 está associada a aumento de risco tanto para o feto quanto para a mãe. Antes da concepção, a prioridade é normalizar a glicemia para prevenir malformações congênitas e abortamentos espontâneos. Com o progresso da gestação, a mãe tem um risco aumentado de hipoglicemias e cetoacidose. Mais tarde existe risco de piora na retinopatia, hipertensão induzida pela gestação, pré-eclâmpsia-eclâmpsia, infecções de trato urinário e poliidrâmnios. No final da gestação, existe o risco de macrossomia e morte súbita intra-uterina do feto. Todas essas complicações podem ser prevenidas ou, pelo menos, minimizadas pelo planejamento da gestação e pelo controle intensivo das oscilações das glicemias, mantendo-as próximo ao normal.

As a result of the advances in glucose monitoring and insulin administration, there has been a dramatic improvement in the outcomes of pregnancy in diabetic women over the past decades. Pregnancy in type 1 diabetic women is associated with an increase in risk both to the fetus and to the mother. The normalization of blood glucose in order to prevent congenital anomalies and spontaneous abortions is considered a priority. As the pregnancy progress, the mother is at an increased risk for hypoglycemia or diabetic ketoacidosis. Later in the pregnancy, she is at risk of accelerated retinopathy, pregnancy-induced hypertension and preeclampsia-eclampsia, urinary tract infection, and polyhydramnios. At the end of pregnancy, there is also an increased risk of macrosomia and sudden death of the fetus in uterus. All of these complications can be prevented or, at least, minimized with careful planning of the pregnancy and intensive tight glucose control.

Transforming Growth Factor-beta Levels in Human Aqueous Humor of Glaucomatous, Diabetic and Uveitic Eyes

PURPOSE: Transforming growth factor-beta2 is known to be present at elevated levels in the aqueous humor of patients with primary open angle glaucoma (POAG) and diabetes but not in uveitis-related secondary glaucoma. We investigated total TGF-beta2 levels and levels of the active form of TGF-beta2 in the aqueous humor of eyes with different types of glaucoma. METHODS: The concentration of the total and active form of TGF-beta2 was measured in 63 patients with primary open angle glaucoma, neovascular glaucoma complicated with diabetes (NVG), and secondary open angle glaucoma complicated with uveitis (SOAG) using a double antibody 'sandwich-indirect' ELISA method. RESULTS: The levels of total TGF-beta2 in the aqueous samples of POAG, NVG, and SOAG were elevated. The levels of active TGF-beta2 in the aqueous samples of POAG, and NVG were also elevated, whereas the level of active TGF-beta2 was within the normal range in the aqueous samples of SOAG. CONCLUSIONS: These results suggest that the level of TGF-beta2 may play a role in the pathology of various types of glaucoma.

Efectos oculares del suplemento de sacarosa en la dieta y su correlación con la cantidad de agregados plaquetarios circulantes en la rata

Varios modelos experimentales reproducen las manifestaciones oculares de la diabetes mellitus, así es el caso del modelo no diabético de suplemento de sacarosa en la rata, el cual es un modelo no diabético que reproduce la nagiopatía diabética, con secreción de insulina normal. Durante seis meses de experimentación, encontramos cambios oculares importantes como cataratas bilaterales, despoblación de las células ganglionares de la retina, así como hipoagregabilidad plaquetaria in vitro. Todo esto, en ausencia de niveles altos de glucosa en la sangre, indica una alta disponibilidad metabólica de la glucosa, lo que determina las lesiones en el cristalino y retina encontradas en este estudio. Este modelo experimental tambien confirma el desarrollo de la hipoagregabilidad plaquetaria in vitro, la cual puede ser atribuída a la estimulación de las plaquetas in vivo.

Human centrifugation: new approach in the treatment of diabetic background retinopathy; preliminary communication

En trabajos previos reportamos que el Tratamiento por Centrifugación Humana (TCH) provocaba liberación endógena de prostaglandinas por un estímulo mecánico sobre la pared de los vasos. Hasta el momento actual, la importancia de la Prostaciclina (PGI) y el TCH en el tratamiento de la retinopatía diabética no ha sido investigado. Hemos evaluado la evolución de la agudeza visual y el fundus ocular al mes, a los 3 meses, a los 6 meses y al año despues del TCH en veintecinco paciente. Los niveles de PGI2 fueron determinados pre y post TCH en siete pacientes y cuatro voluntarios normales. El TCH realizado en una centrífuga Modelo Isasi. Los pacientes fueron expuestos diariamente a perfiles de aceleración de la cabeza a los pies -por una hora durante un mes. Esta comunicación preleminar demostró que: a) El RCH provoca liberación de PGI2 (p < 0.001). b) El TCH substancialmente visual (p < 0.001). c) El TCH tiene efectos beneficiosos a largo prazo

Cellular components of proliferative vitreoretinal membranes

To understand the pathogenesis of proliferative vitreoretinal membrane formation which occurs in proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR), etc., accurate identification of the cellular components of the membrane is needed. This study was performed to identify cellular components of the membranes by means of immunohistochemical technique. 11 proliferative vitreoretinal membranes which were surgically obtained from 7 eyes with PVR and 4 eyes with PDR were stained with monoclonal antibodies against cytokeratin, glial fibrillary acidic protein (GFAP), or vimentin using immunoperoxidase technique (ABC method). In the PVR membranes, mean cell positivities for cytokeratin, GFAP and vimentin were 48%, 1% and 92%, respectively and in the PDR membranes, 0%, 5% and 93%, respectively. The above results suggest that retinal pigment epithelial cells and fibroblasts are major cellular components of PVR membranes, and that mesenchymal cells are major cellular components and glial cells are minor cellular components of PDR membranes.

Cambios del potencial eléctrico de la retina en la diabetes mellitus / Changes in retinal electric potential in diabetes mellitus

Diferentes métodos electrofisiológicos han sido utilizados para caracterizar las alteraciones funcionales de la retina y la vía visual en la en la diabetes. Se discute si los cambios del electrorretinograma (ERG) pueden preceder a las manifestaciones oftalmoscópicas y si guardan relación con el grado de afectación retiniana. Se trata de demostrar este hecho llevando a cabo el registro del ERG con potenciales oscilatorios a un grupo de 60 pacientes diabéticos en tres estadios fondoscópicos diferentes. Los resultados del ERG en estos 3 grupos estuvieron en exacta correspondencia con el grado de afectación retiniana. Los potenciales oscilatorios (PO) fueron los más alterados significativamente. En el primer grupo se estableció una comparación entre el grado de afectación funcional de la retina mediante ERG y los hallazgos de la angiografía con fluoresceína en 10 pacientes sin retinopatía apreciable oftalmoscópicamente. Este estudio mostró la afectación de los PO en los estadios prerretinopáticos en todos los casos, mientras sólo en 2 se observaron microaneurismas mediante la angiografía