Diabetic retinopathy is a vascular complication of diabetes, and homocysteine is an intermediate product of methionine metabolism. Hyperhomocysteinemia can directly or indirectly damage vascular endothelial cells, causing vascular endothelial cells dysfunction and participating in the occurrence and development of diabetic retinopathy. Uric acid is the final product of purine metabolism. Hyperuricemia can cause vascular endothelial dysfunction, oxidative metabolism, platelet adhesion and aggregation dysfunction, thus participating in the occurrence and development of diabetic retinopathy. In recent years, there have been many studies on the correlation between diabetic retinopathy and levels of homocysteine and uric acid. This article reviews the relevant literature at home and abroad in order to provide new information for the prevention and treatment of diabetic retinopathy.
Objective Methods Ninety male Wister rats were randomly divided into normal control group, diabetic group and FTY720 group, thirty rats in each group. Diabetes was induced by giving a single intraperitoneal injection of streptozocin. FTY720 group was administered with FTY720 at a dose of 0.3 mg/kg by oral gavage daily for 3 months after establishment of diabetes. All rats were used for experiments following intervention for 3 months in FTY720 group. Immunohistochemical staining was used to observe the expression and distribution of intercellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1), and the positive cells were counted. Real-time reverse transcription PCR was used to measure mRNA expression of ICAM-1 and VCAM-1. Fluorescein isothiocyanate-Concanavalin A perfusion was used to detect retinal leukocytes adhesion. Evans blue (EB) perfusion was used to analyze retinal vascular permeability. Immunofluorescence staining was used to detect retinal inflammatory cells infiltration. Results In diabetic group, both ICAM-1(t=12.81) and VCAM-1 (t=11.75) positive cells as well as their mRNA expression (t=16.14, 9.59) were increased compared with normal control group, with statistical significance (P < 0.05). In FTY720 group, both ICAM-1(t=-9.93) and VCAM-1 (t=-6.61) positive cells as well as their mRNA expression (t=-15.28, -6.10) were decreased compared with diabetic group, with statistical significance (P < 0.05). Retinal leukocytes adhesion (t=16.32) and EB permeability (t=17.83) were increased in diabetic group compared with normal control group, while they were decreased in FTY720 group compared with diabetic group(t=-9.93, -11.82),with statistical significance (P < 0.05). There were many CD45 positive leukocytes infiltration in retina of diabetic group, including CD11b positive macrophage/activated microglia, while both of them were little in FTY720 group. Conclusions FTY720 can decrease retinal leukocytes adhesion, reduce retinal vascular permeability and inflammatory cells infiltration, which is associated with down-regulation of ICAM-1 and VCAM-1.
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.
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.
ObjectiveTo observe the expression of vascular endothelial growth factor (VEGF) and aquaporin 4 (AQP4) in the inner limiting membrane (ILM) of diabetic retinopathy (DR) with macular edema, and analyze the correlation between VEGF and AQP4 expression. Methods A cross-sectional study. From September 2019 to September 2020, 38 eyes of 38 patients with DR and idiopathic macular hole (iMH) who underwent vitrectomy (PPV) combined with ILM stripping at the Hangzhou campus of The Affiliated Eye Hospital of Wenzhou Medical University at Hangzhou were included in the study. Among them, there were 25 males and 13 females who aged 37-76 years old, average age was 59±10 years old; All eye included 15 right eyes and 23 left eyes. iMH and DR included 9 eyes in 9 cases and 29 eyes in 29 cases, respectively, and they were divided into iMH group and DR group. The DR group was divided into DME group and no DME group according to whether it was accompanied by diabetic macular edema (DME), with 14 eyes and 15 eyes respectively. After the stripped ILM tissue was fixed, immunofluorescence analysis was performed to obtain a picture of the fluorescence mode of AQP4 and VEGF, and the fluorescence intensity value of VEGF and AQP4 was measured by Image J software. The differences of VEGF and AQP4 immunofluorescence values in the specimens between groups were compared by one-way analysis of variance. The correlation between the fluorescence intensity of AQP4 and the fluorescence intensity of VEGF was analyzed by Pearson correlation analysis. Results The average fluorescence intensity valuesof VEGF and AQP4 in ILM specimens of DME group, no DME group and iMH group were 38.96±7.53, 28.25±3.12, 30.07±4.84 and 49.07±8.73, 37.96±6.45, 38.08±5.04, respectively. The average fluorescence intensity of VEGF and AQP4 in the ILM specimens of the DME group was significantly higher than that of the no DME group and iMH group, and the difference was statistically significant (F=13.977, 9.454; P＜0.05). The average fluorescence intensity values of VEGF and AQP4 on IML specimens in the DR group were 33.80±7.91, 43.76±9.44, respectively. The results of Pearson correlation analysis showed that the fluorescence intensity of VEGF and AQP4 in the ILM specimens of the DR group was significantly positively correlated (r=0.597, P=0.003). ConclusionsThe expressions of VEGF and AQP4 in ILM of eyes with DR and DME are significantly increased compared with those without DME. The expression of VEGF and AQP4 in ILM of eyes with DR is positively correlated.
ObjectiveTo observe the effect of preoperative intravitreal ranibizumab injection (IVR) on the operation duration of vitrectomy and postoperative vision for the treatment of proliferative diabetic retinopathy (PDR). MethodsA prospective study was carried out with the 90 PDR patients (90 eyes) who underwent vitrectomy. The 90 patients(90 eyes)were assigned to the vitrectomy only group(43 eyes) and the IVR combined with vitrectomy group (47 eyes). The IVR was performed 5-13 days prior to vitrectomy in the IVR combined with vitrectomy group. There were 15 eyes with fibrous proliferation PDR (FPDR), 16 eyes with advanced PDR (APDR) without involving the macular and 16 eyes with APDR involving the macular in the vitrectomy only group. There were 14 eyes with FPDR, 15 eyes with APDR without involving the macular and 14 eyes with APDR involving the macular patients in the IVR combined with vitrectomy group. All the eyes in the two groups were regularly operated by the same doctor to complete the vitrectomy. The start and end time of vitrectomy were recorded. The average follow-up time was 10 months. The changes of best corrected visual acuity (BCVA) before and 1, 3 and 6 months after surgery were compared between the two groups. ResultsThe duration of operation of the FPDR type (t=-8.300) and the APDR involving the macular type (t=-2.418) in the IVR combined with vitrectomy group was shorter than vitrectomy only group (P < 0.05). The comparison of duration of operation of the APDR without involving the macular type in the two groups has no statistically significant difference (t=-1.685, P > 0.05). At 1 month after surgery, the comparison of BCVA of the IVR combined vitrectomy group and the vitrectomy only group in APDR involving the macular type has no statistically significant difference (t=0.126, P > 0.05). At 3, 6 months after surgery, the BCVA of the IVR combined vitrectomy group in APDR involving the macular type was significantly better than the BCVA of the vitrectomy only group (t=8.014, 7.808; P < 0.05). At 1, 3, and 6 months after surgery, the BCVA of the IVR combined vitrectomy group in FPDR type (t=3.809, 1.831, 0.600) and APDR without involving the macular type (t=0.003, 1.092, 3.931) compared with pre-treatment, the difference were not statistically significant (P > 0.05); the BCVA in APDR without involving the macular type compared with pre-treatment, the difference was distinctly statistically significant (t=2.940, 4.162, 6.446; P < 0.05); the BCVA in APDR involving the macular type (t=0.953, 1.682, 1.835) compared with pre-treatment, the difference were not statistically significant (P > 0.05). ConclusionPreoperative IVR of PDR can shorten the operation duration and improve the BCVA of APDR involving the macular type.
Diabetic retinopathy (DR) is one of the microvascular complications of diabetes mellitus (DM). Like other macrovascular complications of DM, the development and progression of DR is influenced by a variety of systemic and local factors. It is essential to understand the importance of multidisciplinary collaboration. Systemic risk fators such as hyperglycemia, hypertension, dyslipidemia and diabetic nephropathy should be treated before effective DR management can be implemented. Through multidisciplinary collaboration, we can prevent the development of DR, slow the progression of DR, and improve the safety of perioperative care. Thereby enhancing the level of prevention and control of DM complications, including DR.
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.