Epigenetic modifications such as DNA methylation, histone post-translational modifications, non-coding RNA are reversible, heritable alterations which are induced by environmental stimuli. Major risk factors of diabetes and diabetic complications including hyperglycemia, oxidative stress and advanced glycation end products, can lead to abnormal epigenetic modifications in retinal vascular endothelial cells and retinal pigment epithelium cells. Epigenetic mechanisms are involved in the pathogenesis of macular edema and neovascularization of diabetic retinopathy (DR), as well as diabetic metabolic memory. The heritable nature of epigenetic marks also playsakey role in familial diabetes mellitus. Further elucidation of epigenetic mechanisms in DR can open the way for the discovery of novel therapeutic targets to prevent DR progression.
Purpose To identify matrix metalloproteinase (MMP) in human vitreous samples of diabetic vitreoretinopathy (DR) and other ocular diseases (non-DR) and to probe the related factors of MMP expression． Methods Thirty-one diabetic and 17 non-diabetic vitreous samples (nine macular hole and eight epiretinal membrane patients) were examined． Samples were concentrated and subjected to substrate zymography to conduct a quantitative analysis of MMP-2,9 activity． The technology of Western blotting against anti-human MMP-2,9 was performed to identify MMP in vitreous samples． Results Vitreous samples both from DR patients and from non-DR patients showed a single band at the position of 72 kDa, correspondin g to MMP-2． Quantitative analysis revealed that diabetic vitreous showed higher MMP-2 activity than non-DR, although the difference was not significant.45.2% of DR patients showed MMP-9, but no expression in non-DR．Among DR samples, the positive ratio of MMP-9 in partial posterior vitreous detachment (PVD)(66．7%) was significantly higher than that of complete PVD (15．4%)． Western blotting study confirmed the expression of MMP-2 and MMP-9． Conclusion There is no obvious difference of MMP-2 activity between DR and non-DR． MMP-9 may be involved in the pathogenesis of diabetic vitreor etinopathy and the deterioration of proliferative change． (Chin J Ocul Fundus Dis, 2001,17:195-197
ObjectiveTo observe the clinical effect of microincision vitreoretinal surgery (VRS) assisted with intravitreal injection of ranibizumab (IVR) in severe proliferative diabetic retinopathy (PDR) treatment. MethodsThis is a prospective non-randomized controlled clinical study. A total of 60 patients (70 eyes) with severe PDR diagnosed were enrolled and divided into IVR group (31 patients, 35 eyes) and control group (29 patients, 35 eyes). IVR group patients received an intravitreal injection of 0.05 ml ranibizumab solution (10 mg/ml) first, and 3 or 4 days later they received 23G microincision VRS. Control group patients only received 23G microincision VRS. The follow-up time was 3 to 12 months with an average of (4.5±1.8) months. The logarithm of the minimal angle of resolution (logMAR) best corrected visual acuity (BCVA), intraocular pressure, the central retinal thickness (CRT) and retinal reattachment, and the incidence of postoperative complications were comparatively analyzed. ResultsThere was no topical and systemic adverse reactions associated with the drug after injection in IVR group. The incidence of post-operative vitreous hemorrhage (VH) in IVR group and control group was 8.6% and 28.6% at 1 week after surgery, 0.0% and 17.1% at 1 month after surgery, 0.0% and 8.6% at 3 month after surgery respectively. The differences were statistically significant for 1 week (χ2=4.63, P < 0.05) and 1 month (χ2=4.56, P < 0.05), but was not statistically significant for 3 months (χ2=0.24, P > 0.05). The mean post-operative logMAR BCVA of IVR group (0.81±0.40) and control group (1.05±0.42) have all improved than their pre-operative BCVA, the difference was statistically significant (t=12.78, 4.39; P < 0.05). The mean logMAR BCVA of IVR group is higher than BCVA of control group, the difference was statistically significant (t=-2.36, P < 0.05). The average post-operative CRT in IVR group was thinner than that of control group, the difference was statistically significant (t=-2.53, P < 0.05). The incidence of a transient high intraocular pressure in IVR group (14.3%) was lower than that in control group (34.3%), the difference was statistically significant (t=4.79, P < 0.05). The incidence of retinal reattachment (t=0.35), epiretinal membrane (χ2=0.97), neovascular glaucoma (χ2=0.51) was no difference between these two groups (P > 0.05). ConclusionThe minimally invasive VRS assisted by IVR treatment for severe PDR can effectively prevent postoperative VH, reduce CRT and improve visual acuity.
Microparticles are small vesicles that are released by budding of the plasma membrane during cellular activation and apoptotic cell breakdown. A spectrum of cell types can release microparticles including endothelial cells, platelets, macrophages, lymphocytes and tumor cells. Biological effects of microparticles mainly include procoagulant activity, inhibition of inflammation and cancer progression. The present study shows that vitreous microparticles isolated from proliferative diabetic retinopathy (PDR) stimulated endothelial cell proliferation and increased new vessel formation, promoting the pathological neovascularization in PDR patients. Oxidative stress induces the formation of retina pigment epithelium-derived microparticles carrying membrane complement regulatory proteins, which is associated with drusen formation and age related macular degeneration. Microparticles from lymphocyte (LMP) play an important role in anti-angiogenesis by altering the gene expression pattern of angiogenesis-related factors in macrophages. Besides, LMP are important proapoptotic regulators for retinoblastoma cells through reduction of spleen tyrosine kinase expression and upregulation of the p53-p21 pathway which ultimately activates caspase-3. However, how to apply the microparticles in the prevention and treatment of retinal diseases is a major challenge, because the study of the microparticles in the fundus diseases is still limited. Further studies conducted would certainly enhance the application of microparticles in the fundus diseases.
Objective To observe the morphological changes of dendrite and soma in retinal ganglion cells (RGCs) which subsisted in early diabetic rats. Methods The RGCs of 3-months-course diabetic rats and coeval normal rats were marked by gene gun techniques. To collect RGCs photographs by Leica microscope with Z axis and CCD camera；to observe the changes of diameter, variance of structural features in dendritic field and somata after classification which according to the size and morphology. Thy-1 antibody marks on the retinal RGCs, taking a photograph under fluorescent microscope, counting the changes of retinal RGCs density in early diabetic rat. Results In three-month diabetic rats,the density of retinal RGCs was decreased obviously. Morphological changes of RGCs in the dendritic fields were observed with gene gun technique. There was no severe variation in all kinds of the bole of cell dendrite, in which some only showed crispation partially and sparseness also twisting in the dendritic ramus. The mean diameter of dendritic field and soma in class A of diabetic rats was (401plusmn;86) mu;m, the mean diameter of dendritic field in control group was (315plusmn;72) mu;m,compared with each other, there is statistically significant differences (t=21.249，Plt;0.001); the mean diameter of soma in class A of diabetic rats was (24plusmn;6) mu;m, the mean diameter of soma in control group was (22plusmn;5) mu;m, compared with each other, there is no statistically significant differences (t=0.927，Pgt;0.05); the mean diameter of dendritic field and soma in class B of diabetic rats were (170plusmn;36)、(14plusmn;2) mu;m respectively, in control group were (165plusmn;36)、(16plusmn;2) mu;m, the mean diameter of dendritic field and soma in class C of diabetic group were(265plusmn;78)、(17plusmn;5) mu;m respectively, in control group were (251plusmn;57)、(17plusmn;4) mu;m , compared with each other, there are on statistically significant differences(t=1.357，0.798，0.835，1.104，Pgt;0.05). Conclusions In short-term diabetes, the survived RGCs show good plasticity in adult diabetic rats, especially in class A. The changes of dendrites were more sensitive than the soma, which could be the leading index of the morphologic changes of RGCs in the early stage. The good plasticity showed by the RGCs and the time window from changing in dendrite to cell death provide us many evidences not only for the research but also for the nerve protection in clinic. (Chin J Ocul Fundus Dis,2008,24:249-254)
ObjectiveTo investigate the expression of interleukin-18（IL-18）and signal transducers and activators of transcription 5（STAT5）in retina of 4-24-week-old diabetic rats, and explore the potential molecular mechanisms involved in diabetic retinopathy (DR).MethodsRetinal gene expression profile of healthy and 8-week-old diabetic rats was established with restriction fragment differential displaypolymerase chained reaction (RFDD-PCR), and the differences was analyzed by bioinformatics. IL-18 and STAT5 were filtrated as the candidate genes of DR. The expression of IL-18 and STAT5 in retina of diabetic rats with the age of 4, 8, and 24 weeks was observed by semi-quantitative reverse transcriptase-polymerase chain reaction（RT-PCR）.ResultsThe result of RFDD-PCR showed:expression of IL-18 was higher in healthy retina than that in diabetic one; expression of STAT5 was not found in healthy rats but in diabetic ones. The result of RT-PCR showed：compared with the normal, high expression of IL-18 was found in 4-week diabetic retina, reduced in 8-week one, and decreased to the lowest in 24-week one. The expression of STAT5 was not observed in healthy or 4week diabetic retina, but occurred in 8-week one, and increased in 24-week one. ConclusionThe expression of IL-18 and the activation of STAT5 may relate to the occurrance of DR. The expression of IL-18 doesn′t depend on the activation of STAT5. (Chin J Ocul Fundus Dis, 2005,21:258-260)
Objective To investigate the effect of advanced glycation end products (AGEs) on the catalase activity and the levels of malondialdehyde in cultured bovine retinal capillary pericytes (BRPs), and to investigate the relationship between oxidative stress and diabetic retinopathy. Methods Cultured BRPs were exposed to AGEs (0, 8, 32, 125, 500, 2 000 μg/ml) for four days. Activity and the levels of catalase and malondialdehyde in cultured BRPs were examined by spectrophotometry. Results AGEs decreased the catalase activity, whereas increased the levels of malondialdehyde of cultured BRPs in a dose-dependent manner (r=-0.714, r=0.748, P＜0.01).There were significant differences between BRPs cultured in 32 μg/ml AGEs and in control group (P＜0.01), while no significant differences between BRPs cultured in non-glycated bovine serum albumin and absence of bovine serum albumin were found. Conclusion Oxidative stress may be one of the reasons why the pericyte disappears in diabetic retinopathy. (Chin J Ocul Fundus Dis, 2002, 18: 143-145)
For the past few years, artificial intelligence (AI) technology has developed rapidly and has become frontier and hot topics in medical research. While the deep learning algorithm based on artificial neural networks is one of the most representative tool in this field. The advancement of ophthalmology is inseparable from a variety of imaging methods, and the pronounced convenience and high efficiency endow AI technology with promising applications in screening, diagnosis and follow-up of ophthalmic diseases. At present, related research on ophthalmologic AI technology has been carried out in terms of multiple diseases and multimodality. Many valuable results have been reported aiming at several common diseases of ophthalmology. It should be emphasized that ophthalmic AI products are still faced with some problems towards practical application. The regulatory mechanism and evaluation criteria have not yet integrated as a standardized system. There are still a number of aspects to be optimized before large-scale distribution in clinical utility. Briefly, the innovation of ophthalmologic AI technology is attributed to multidisciplinary cooperation, which is of great significance to China's public health undertakings, and will be bound to benefit patients in future clinical practice.
Angiopoietin-like protein (ANGPTL), a group of secreted glycoproteins, is widely expressed in vivo and is involved in many pathophysiological processes such as glycolipid metabolism, stem cell growth, local inflammation, vascular leakage and angiogenesis. Many kinds of ANGPTL are closely related to the occurrence and development of diabetic retinopathy (DR), especially ANGPTL4, which has gradually become a new hotspot in the field of DR Research. ANGPTL is involved in glucose metabolism and lipid metabolism, promotes increased vascular permeability, pathological angiogenesis, and participates in intraocular inflammation. ANGPTL is a promising molecular target. It can not only be used as a biomarker to predict the occurrence and progression of DR, but also provide new ideas for the treatment of DR by making antibody drugs to interfere with this molecule.
ObjectiveTo observe the influence of human umbilical cord mesenchymal stem cells (hUCMSC) transplantation into vitreous cavity of diabetic rats on the retinal morphology, and the expression of glial fibrillary acidic protein (GFAP) and rhodopsin (RHO). Methods78 male Sprague-Dawley rats were used. 70 rats were injected with streptozotocin by tail vein injection at a dose of 40 mg/kg to establish the diabetes mellitus model, and another 8 rats were injected with 0.1 mol/L pH 4.0 citric acid buffer at the same dose as the normal control group. After 6 weeks of modeling, 10 rats were taken as the control group of diabetic model. hUCMSC suspension was injected into the right eye vitreous cavity of the remaining 60 rats, and the same volume of Dulbecco's modified Eagle/F12 medium was injected into the left vitreous cavity as control eyes. 1, 2 and 4 weeks after transplantation, follow-up experiments were performed. The experimental eyes were labeled as U1, U2, and U4 groups, while the control eyes were recorded as D1, D2, D4, and each group consisted of 20 eyes. After paraffin section and hematoxylin-eosin staining, the structure of the retina was observed by optical microscopy and the thickness of the outer nuclear layer and the inner nuclear layer (INL) were measured. The distribution and migration of hUCMSC in rat retina were observed by frozen section-tissue immunofluorescence assay. The mRNA and protein expression of GFAP and RHO in the retina were detected by real-time quantitative polymerase chain reaction (PCR) and Western blot assays. ResultsThe results of optical microscope observation showed the normal structure of retina in normal control group. The retinal nerve fiber layer (NFL) was thinned and the number of retinal ganglion cells (RGC) in the control group of diabetic rats was decreased. The decreased number and disorder arrangement of RGC were observed as well in U1, D1 rats. The RGC number of U2, U4, D2, D4 rats was gradually decreased. Compared with D4 group, the thickness of INL in U4 group was significantly increased (P < 0.05). Tissue immunofluorescence assay showed that hUCMSC were distributed along the inner limiting membrane in the retina of the U1 group, while the number of hUCMSC in the U2 group was gradually decreased, mainly in the NFL and ganglion cell layers. Real-time PCR and Western blot data indicated that the relative expression of GFAP mRNA and protein in the diabetic retina was significantly increased, and the relative expression of RHO mRNA and protein decreased gradually in the diabetic model group and the D1, D2, D4 groups. Compared with D2 and D4 groups, the mRNA and protein expression of GFAP in U2 and U4 groups were decreased, and the relative expression of RHO mRNA and protein were all increased (P < 0.01). ConclusionhUCMSC could migrate and integrate into the retina, after the transplantation into the vitreous cavity of diabetic rats, which reduced the expression of GFAP, but enhanced the expression of RHO.