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.
Objective To expolre the factors which affect the size of diabetic,macular fobeal avascss scular zone(FAZ). Methods Making ten years of duration of diabetes a limit,79 nonproliferative and early proliferative diabetic patients were divided into 2 groups.Diabetic retinopathy severity level was diveided into 4 stages,and the macular edema was subdivided into focal、diffuse and cystoid according to fluorescein leakage of foveomacular region.All patients were measured FAZ with Heidelberg scanning laser fluoresceion angiography system and then compaired the size of FAZ of patients with different duration of diabetes、diabetic retinopathy severity level and macular edema status.The results were performed analysis of variance and t test. ResultsThe study shown the size of FAZ was not directly related to the duration of diabetes(t=1.3854,Pgt;0.1);There were significant differences about the size of FAZ of patients with different diabetic retinopathy severity level(F=7.6251,P＜0.01)and macular edema status(F=5.4369,P＜0.01)． Conclusion The size of FAZ was significantly increased in diabetic patients.It was enlarged with the development of diabetic retinopathy severity level,but it was not related to duration of diabetes. (Chin J Ocul Fundus Dis,2000,16:155-156)
ObjectiveTo observe and preliminarily discuss the distribution characteristics of the non-perfusion area (NP) of the retina in different stages of diabetic retinopathy (DR) and its changes with the progression of DR. MethodsA retrospective clinical study. From October 2018 to December 2020, 118 cases of 175 eyes of DR patients diagnosed in Eye Center of Renmin Hospital of Wuhan University were included in the study. Among them, there were 64 males with 93 eyes and 54 females with 82 eyes; the average age was 56.61±8.99 years old. There were 95 eyes of non-proliferative DR (NPDR), of which 25, 47, and 23 eyes were mild, moderate, and severe; 80 eyes were proliferative DR (PDR). Ultra-wide-angle fluorescein fundus angiography was performed with the British Optos 200Tx imaging system, and the fundus image was divided into posterior, middle, and distal parts with Image J software, and the ischemic index (ISI) was calculated. The difference of the retina in different DR staging groups and the difference of ISI were compared in the same area. The Kruskal-Wallis test was used to compare the ISI between the different DR staging groups and the Kruskal-Wallis one-way analysis of variance was used for the pairwise comparison between the groups. ResultsThe ISI of the posterior pole of the eyes in the moderate NPDR group, severe NPDR group, and PDR group were significantly greater than that in the distal periphery, and the difference was statistically significant (χ2=6.551, 3.540, 6.614; P=0.000, 0.002, 0.000). In severe NPDR group and PDR group, the ISI of the middle and peripheral parts of the eyes was significantly greater than that of the distal parts, and the difference was statistically significant (χ2=3.027, 3.429; P=0.015, 0.004). In the moderate NPDR group, there was no significant difference in ISI between the peripheral and distal parts of the eye (χ2=2.597, P=0.057). The ISI of the posterior pole of the eyes in the moderate NPDR group and the PDR group was significantly greater than that in the middle periphery, and the difference was statistically significant (χ2=3.955, 3.184; P=0.000, 0.009). In the severe NPDR group, there was no significant difference in ISI between the posterior pole and the middle periphery of the eye (χ2=0.514, P=1.000). Compared with the mild NPDR group and the moderate NPDR group, the ISI of the whole retina, posterior pole, middle and distal parts of the PDR group was larger, and the difference was statistically significant (χ2=－7.064, －6.349,－6.999, －5.869, －6.695, －6.723, －3.459, －4.098; P=0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.003, 0.000). ConclusionThe NP of the eyes with different DR stages is mainly distributed in the posterior pole and the middle periphery. The higher the severity of DR, the greater the NP in the posterior and middle periphery.
The pathogenesis of diabetic retinopathy (DR) is complex and there are many related risk factors. It is related to the course of diabetes, blood glucose, blood pressure, and blood lipids, among which the course of disease and hyperglycemia are recognized main risk factors. In addition, other factors which include heredity, gender, age, obesity, pregnancy, insulin use, can also affect the occurrence and development of DR, but there is no unified conclusion about its correlation. A comprehensive understanding of the risk factors that affect DR can provide new ideas for the prevention, diagnosis, treatment, and intervention of DR.
Diabetic retinopathy (DR) is one of the most common and serious complication of diabetes mellitus, which is the main cause of vision loss in adults. Biological clock genes produce circadian rhythms and control its operation, while the disorder of the expression causes the occurrence and development of a series of diseases. It has been demonstrated that biological clock genes might take effects in the development and progression of DR. On the one hand, circadian rhythm disorder-related behavior disrupts the circadian oscillation of clock genes, and the change in its expression level is prone to unbalanced regulation of glucose metabolism, ultimately increasing the risk of type 2 diabetes mellitus and DR pathogenesis. On the other hand, DR patients exhibit symptoms of circadian rhythm disorders, and it has been suggested that the clock genes may control the development and progression of DR by affecting a variety of retinal pathophysiological processes. Therefore, maintaining normal circadian rhythm can be used as a disease prevention strategy, and studying the molecular mechanism of clock genes in DR can provide new ideas for more comprehensive elaboration of the pathogenesis of DR and search for new therapeutic targets.
ObejctiveTo investigate the consistency and reproducibility of macular perfusion parameters in early diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA).MethodsA prospective cross-sectional observational study. Forty-six patients (46 eyes) diagnosed with mild nonproliferative DR were included in this study. There were 24 males and 22 females, with the mean age of 59.16±10.32 years. Two macular scan sizes of 3 mm×3 mm and 6 mm×6 mm were performed by the same operator, and the same test was performed by another operator. The superficial retinal layer (SRL) and deep retinal layer (DRL) in the foveal avascular zone (FAZ) and vessel density (VD) were quantified. The consistency of the two scan sizes and the reproducibility of the same scan size were also evaluated. The consistency was determined by the intraclass correlation coefficient (ICC). If the intraclass correlation coefficient (ICC)＞0.80, consistency was good; if 0.4≤ICC＜0.8, consistency was general; if ICC＜0.40, consistency was poor.ResultsIn the 3 mm×3 mm and 6 mm×6 mm scanning sizes, the mean results of the two examiners were calculated. The FAZ of SRL were 0.39±0.13 mm2 and 0.42±0.15 mm2, FAZ of DRL were 0.74±0.22 mm2 and 0.89±0.23 mm2. The VD of SRL were (32.23±2.86)% and (31.91±3.01)%, VD of DRL were (43.73±4.64)% and (45.12±5.49)%. The consistency analysis showed that the ICC of SRL-FAZ and DRL-FAZ were 0.920 and 0.812, respectively; the ICC of VD were 0.833 and 0.830, respectively. The consistency was good. The reproducibility analysis of different examiners in the same scan size was better in the consistency of SRL FAZ and VD.ConclusionOCTA in two scanning sizes to measure FAZ and VD of early DR has good consistency and reproducibility.
The exact pathophysiological mechanisms of diabetic retinopathy (DR) remain elusive. The inflammatory reaction, retinal vascular leakage and retinal neovascularization are main features of DR. Adiponectin (APN) is an endogenous biological active protein secreted by adipocytes. It can increase insulin sensitivity, regulate blood glucose and lipid metabolism, and has anti-inflammation and anti-neovascularization functions. It may be involved in the development of DR. This review summarized the studies on the association between APN and DR in recent years.
ObjectiveTo observe the expression of Toll-like receptor 4 (TLR4) and inflammatory cytokines, leucocytic density and permeability in retina of diabetic rat. MethodsA total of 106 Brown Norway rats were randomly divided into experimental group and control group with 53 rats in each group. Diabetic model was established in experimental group by intraperitoneal injection of streptozotocin, and control rats received intraperitoneal injection of an equal volume of citric acid-sodium citrate buffer. Four weeks later, the retinas were collected for further analysis. TLR4 RNA and protein expression were measured by quantitative polymerase chain reaction and Western blot. Inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), monocyte chemo-attractant protein-1 (MCP-1), were measured by enzyme-linked immunosorbent assay in rat retina homogenate. Leukocyte density in the retina was measured by acridine orange fundus angiography. The retinal permeability was evaluated by Evans blue (EB) staining. ResultsTLR4 expression was significantly increased in diabetic rats of experimental group compared with non-diabetic rats of control group (F=1.606, 0.789; P < 0.05). Inflammatory cytokines (TNF-α, IL-1β and MCP-1) were significantly increased in retina of diabetic rats of experimental group versus non-diabetic rat of control group (F=24.622, 5.758, 4.829; P < 0.05). The retinal leukocyte density was (6.2±0.5)×10-5, (2.2±0.3)×10-5 cells/pixel2 in experimental and control group respectively, the difference was statistically significant (F=2.025, P < 0.05). The amount of retinal EB leakage was (23.41±4.47), (13.22±3.59) ng/mg in experimental and control group respectively, the difference was statistically significant (F=21.08, P < 0.05). ConclusionTLR4 and inflammatory cytokines expression, leucocytic density and permeability increased significantly in retina of diabetic rat.
ObjectiveTo observe the lipid metabolism characteristics of type 2 diabetes mellitus (T2DM) patients with different levels of blood glucose control and preliminarily analyze their relationship with diabetic retinopathy (DR). MethodsA retrospective clinical study. From January 2019 to January 2024, 232 T2DM patients who underwent fundus examination in Department of Ophthalmology of Yichang Central People’s Hospital were included in the study. Based on the glycated hemoglobin A1c (HbA1c) test results, patients were divided into blood glucose standard group and blood glucose non standard group, with 100 and 132 cases respectively. Based on the results of fundus fluorescein angiography, patients were divided into non DR (NDR) group and DR group, with 89 and 143 cases, respectively. 100 healthy individuals who underwent physical examinations during the same period were selected as the control group. The thickness of peripapillary retinal nerve fiber layer (pRNFL) around the optic disc, the blood flow density of radial peripapillary capillaries (RPC) around the optic disc, and the thickness of ganglion cell complex (GCC) in the upper and lower parts of the optic disc and macular area were measured by optical coherence tomography angiography instrument. Fully automated biochemical analyzer was used to detect serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and HbA1c. After adjusting for confounding factors, multiple linear regression model was used to analyze the correlation between HbA1c and blood lipids. Multiple logistic regression analysis was conducted to investigate the correlation between TG, HDL-C, and the occurrence of DR. ResultsCompared with the control group, both the blood glucose standard group and the blood glucose non standard group had higher levels of HbA1c (F=8.115), TC (F=4.373), TG (F=20.220), and LDL-C (F=12.271), and lower levels of HDL-C (F=6.349), with statistically significant differences (P＜0.05). Compared with the blood glucose standard group, patients in the blood glucose non standard group had higher levels of serum HbA1c (t=3.531), TC (t=2.561), TG (t=6.418), LDL-C (t=7.880), and lower levels of HDL-C (t=5.152), with statistically significant differences (P＜0.05). Correlation analysis showed that HbA1c was positively correlated with TC, TG, and LDL-C (P＜0.05), and negatively correlated with HDL-C (P＜0.05). Multiple logistic regression analysis showed that TG, LDL-C, and HDL-C were independent risk factors for the occurrence of DR (Ptrend＜0.05). Compared with the NDR group, the DR group had thinner GCC and pRNFL thickness in the upper part of the optic disc, and lower overall and RPC blood flow density in the upper part of the optic disc, with statistically significant differences (t=4.964, 2.406, 2.685, 2.404; P＜0.05). Correlation analysis results showed that TG, LDL-C, HDL-C, HbA1c were correlated with GCC thickness, pRNFL thickness, and RPC blood flow density (P＜0.05). ConclusionsThe higher the blood glucose level in T2DM patients, the more likely they are to experience dyslipidemia. TG, LDL-C, and HDL-C are independent risk factors for the occurrence of DR. Abnormal blood lipids and blood glucose levels in T2DM patients can affect retinal nerves, blood vessels, and function.
ObjectiveTo compare the outcomes of 23G and 25G plus (25G+) vitrectomy in treatment of proliferative diabetic retinopathy (PDR). MethodsThis is a prospective randomized study. Fifty-seven PDR patients (75 eyes) with symptoms requiring vitrectomy were randomly divided into 23G vitrectomy group (30 patients, 39 eyes) and 25G+ vitrectomy group (27 patients, 36 eyes). Visual acuity, intraocular pressures, ophthalmoscopy, B-scan ultrasound was examined before surgery. The follow-up period was 10.0 (23G group) and 8.5 months (25G+ group) respectively. Intraoperative complications, operation time, postoperative visual acuity, intraocular pressure, postoperative complications and postoperative ocular conditions were analyzed. ResultsThe mean surgical times were (53.35±7.42) minutes and (49.16±5.17) minutes in 23G and 25G+ group respectively, and the difference was significant (t=4.37, P < 0.05). Iatrogenic injuries occurred in 11 eyes (28.21%) and 5 (13.89%) eyes in 23G and 25G+ group respectively, and the difference was significant (χ2=4.93, P < 0.05). The postoperative visual acuity of 23G and 25G+ group were improved compared to before surgery (χ2=16.81, 18.29; P < 0.05). At last follow-up, there was 25 eyes and 24 eyes with visual acuity≥0.05 in 23G and 25G+ groups respectively, and the difference was not significant (χ2=0.13, P > 0.05). Hypotony was detected in 7 and 3 eyes at the third postoperative day in 23G and 25G+ group respectively, and the difference was significant (χ2=5.67, P < 0.05). Conclusion25G+ vitrectomy is a safe and effective treatment for PDR with shorter surgery time and fewer surgical complications.