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.
The prevalence of diabetes mellitus in adults of China has reached 12.8%. Diabetic retinopathy (DR) accounts for approximately 1/4-1/3 of the diabetic population. Several millions of people are estimated suffering the advanced stage of DR, including severe non-proliferative DR (NPDR), proliferative DR (PDR) and diabetic macular edema (DME), which seriously threat to the patients’ vision. On the basis of systematic prevention and control of diabetes and its complications, prevention of the moderate and high-risk NPDR from progressing to the advanced stage is the final efforts to avoid diabetic blindness. The implementation of the DR severity scale is helpful to assess the severity, risk factors for its progression, treatment efficacy and prognosis. In the eyes with vision-threatening DR, early application of biotherapy of anti-vascular endothelial growth factor can improve DR with regression of retinal neovascularization, but whether it is possible to induce capillary re-canalization in the non-perfusion area needs more investigation. Laser photocoagulation remains the mainstay treatment for non-center-involved DME and PDR.
Objective To observe the oxidative damage of mtDNA, apoptosis and expression of adhesion molecules in retinal capillary cells of diabetic rat with different disease courses. Methods One hundred Sprague-Dawley rats were randomly divided into the control group and the experimental group. The rats of experimental group were induced with streptozotocin (STZ) injection creating a diabetic model. Then they were divided into DR1m, DR2m DR3m group according to disease courses. The rats of control group were divided into NR1m, NR2m, NR3m group. Rat retinal capillaries were prepared, and then the contents of undamaged mtDNA were examined by Southern blot combined with Fpg. The expression of cyclooxygenase (COX)-1 encoded by mtDNA and transcription factors A (mtTFA) mRNA were detected by real-time quantitative polymerase chain reaction (RT-PCR). Apoptosis and expression of intercellular adhesion molecule-1 (ICAM-1) were detected by terminal dUT nick endlabeling (TUNEL) immuno-fluorescence and immunohistochemistry respectively. Results The contents of undamaged mtDNA in rats of DR1m, DR2m, DR3m were less than those of NR1m、NR2m、NR3m. The contents of undamaged mtDNA in diabetic rats decreased with the increase of disease courses. In addition, the mRNA levels of COX-1 and mtTFA were downregulated in diabetic rats. The positive cells of TUNEL and ICAM-1TUNEL and ICAM-1 in diabetic rats increased with the increase of disease courses. Conclusion With the increase of disease courses, mtDNA damage and apoptotic cells are increased, while the expression of mRNA encoded by mtDNA and ICAM-1 decreased in retinal capillary cells in diabetic rats.
Purpose To observe the color motion perception of patients with diabetic retinopathy (DR) in very early stage and find a good way to diagnose early DR in time． Methods The motion perceptions of patients with early DR and normal subjects were tested by using equiluminant moving chromatic grating and moving luminance grating generated on VGA monitor in a PC compatible computer and the results were compared with those of electroretinogram(ERG),oscillatory potentials(OPs) and color perception． Results When the two gratings were of equal spatial frequency and equal time frequency,the normal subjects judged that chromatic grating moved faster than luminance grating．Very signifincant differences were detected between blue/yellow grating and black/white grating while the luminance contrast of was 80% and the velocity was 20.2 mm/s or 14.3mm/s(Plt;0.01).The abnormal ratio of color motion perception(69.2%)was higher than that of color vision(43.6%) and ERG OPs(48.9%) when the luminance contrast of black/white grating was 80% and the velocity was 20.2mm/s. Conclusion The test of color motion perception provides new method for diagnosing early DR. (Chin J Ocul Fundus Dis,1998,14:135-138)
Epigenetics refers to the changes in gene expression level and function caused by non-genetic sequence changes. It can provide the time, location and mode of the genetic information for the execution of DNA sequences, including DNA methylation, histone modification, non-coding RNA and chromatin remodeling. Studies had shown that epigenetics plays an important role in the development of diabetic retinopathy (DR), and it had been found that epigenetic-related treatment regimens had a certain effect on the treatment of DR through animal experiments and in vitro experiments. It was benefit to regulate the development of diabetes and its complications by depth study of DNA methylation, histone modification, miRNA and metabolic memory. An understanding of changes in gene transcriptional mechanisms at the epigenetic level could help us to further study the prevention and control of diabetes and its complications, and to provide new ideas for treatment.
Diabetes retinopathy (DR) is listed as one of the chronic diseases that should be focused on in the “14th Five-Year” National Eye Health Plan (2021-2025). Early screening is one of the effective measures to reduce blindness caused by DR. Establishing an efficient and practical community screening model is a powerful guarantee for completing early screening. The Ocular Fundus Diseases Group of the Ophthalmology Branch of the Chinese Medical Association has led the development of Expert consensus on community screening of diabetic retinopathy among DR community screening experts that is suitable for the current national situation, in order to guide and promote the further improvement of DR community screening work in China. This Expert Consensus provides detailed specifications on the current domestic trend of DR, the necessity of screening, the role of artificial intelligence grading, screening process, and quality control. This interpretation further emphasizes the importance of DR community screening, while emphasizing the responsibilities of different departments in the screening process. Finally, recommendations are provided for the sustainability of DR community screening. It is hoped that the screening rate of DR in China can be improved and blindness can be reduced by DR through Expert consensus on community screening of diabetic retinopathy and interpretation of the content.
Objective To observe the effect of high glucose on the expression of activating transcription factor 4 (ATF4) in cultured retinal Muuml;ller glia cells. Methods The retinal tissue of Sprague-Dawley (SD) rats was collected, and Muuml;ller cells were isolated and cultured. The glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS) of Muuml;ller cells were identified by streptavidin-biotin-peroxidase complex. Cultured rat Muuml;ller cells were divided into control group (5.5 mmol/L glucose), group A (20 mmol/L glucose), group B (30 mmol/L glucose) and group C (40 mmol/L glucose). ATF4 protein expressions in Muuml;ller cells of four groups were measured by Western blot four days after cultured. Results GFAP and GS expressed in more than 95% of Muuml;ller cells. Over 95% of Muuml;ller cells of group A, B and C were positive for GFAP and GS. Western blots indicated that ATF4 protein in group A, B and C increased obviously compared with the control group (q=0.293, 0.754,0.484;P＜0.05). Conclusion High glucose can increase the expression of ATF4 protein and cause endoplasmic reticulum stress in retinal Muuml;ller glia cells in vitro.
The therapeutic effects of panretinal cryotherapy(PRC)on proliferative diabetic retinopathy(PDR)were prospectively investigated in 80 eyes with PDR of 44 patients.Forty eyes with PDR(20 of them stage Ⅳ and 20 stage Ⅴ)received PRC operation.Of the 80 eyes,the other 40 ones with stage Ⅳ and Ⅴ similar to the formers were observed conservatively as controls.The follow up duration was 2 years.We found that in the cases of stage Ⅳ,no more remarkable visual loss was found after operation.There was a significant difference comparing with the control（P＜0.002）,and the retinal neovascularization regressed more noticeably than the control group（P＜0.001）.In the cases of stage Ⅴ,the incidence of the traction retinal detachment was 55% in the operated group,and was 20% in the control group.There was a statistic difference between them（P＜0.05）.The clearance of the vitreous hemorrhage was more rapid in the operated group than the control（P＜0.025）.The above results suggest that cryotherapy is suitable for the cases of earlier stage which cannot be performed with photocoagulation for any reasons,but not for the patients with advanced retinal proliferation.Photocoagulation for any reasons,but not for the patients with advanced retinal proliferation. （Chin J Ocul Fundus Dis,1993,9:148-151）