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
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.
Objective To observe the expression of p53, bcl-2 genes, vascular endothelial cell growth factor（VEGF）, basic fibroblast growth factor（bFGF）, insulin-like growth factor-I （IGF-I）, and the receptors of these factors of retinal vascular endothelial cells (VECs) of 1- to 20-week diabetic rats, and the relationship between the expressions and cell cycle arrest.Methods Retinal sections of diabetic rats induced by alloxan were immunohistochemically stained and observed by light microscopy (LM) and electron microscopy (EM). Dot blotting and Western blotting were used to determine the expression of mRNA, proteins of p53 and bcl-2. Results Under LM, immunohistochemical positive expression of p53 and bcl-2 were found on the vessels of ganglion cell layer and inner nuclear layer of retinae of 8- to 20-week diabetic rats; under EM, these substances were observed depositing in VECs. The retinal VECs also expressed VEGF, bFGF, IGF-I and their receptors. There was no positive expression of other cell types in these retinae, all cell types of retinae in control group, or all cells of retinae of diabetic rats with the course of disease of 1 to 6 weeks. The result of dot blotting revealed that retinal tissue of 20-week diabetic rat expressed p53 and bcl-2 mRNA, and the result of Western blotting revealed that they also expressed p53 and bcl-2 proteins. But retinal tissues of control group did not. Positive expression of bax was not found in the retinae in control group or 1- to 20-week diabetic rats. Conclusion p53, bcl-2 may introduce cell cycle arrest of VECs of retinae in 8- to 20-week diabetic rats. High glucose might stimulate the expression of VEGF, bFGF, IGF-I and their receptors, and the growth factors may keep VECs surviving by self-secretion. (Chin J Ocul Fundus Dis，2003，19：29-33)
Objective
To observe the short-term effect of changing the sequence of PRP and MLP on the pre-proliferative or proliferative diabetic retinopathy patients with clinical significant macular edema (CSEM).
Methods
Sixty-three consecutive pre-proliferative or proliferative diabetic retinopathy outpatients (103 eyes) with clinical significant macular edema were selected and divided into two groups: 54 eyes in patients of group A accepted MLP one month prior to PRP and 49 eyes in patients of group B accepted the photocoagulative therapies in a contrary sequence. All the patients were followed up for 3 to 13 months and visual acuity. Light sensitivity of 5deg;macular threshold, and FFA were performed pre- and post-photocoagution.
Results
The improvement of visual acuity was found to be better in group A than that of group B (Plt;0.01) 2 months after the therapy, since then, there was no significant defference (Pgt;0.05) in both groups. Three and 4 months after the treatment, there was no significant difference in change of light sensitivity of 5deg;macular threshold in both groups. The macular leakages of 59 eyes, 32 ingroup A and 27 in group B, were well controlled.
Conclusion
Among the pre-proliferative or proliferative diabetic retinopathy patients with CSEM, visual acuity of those who accept MLP prior to PRP more rapidly than those who accept contrary sequence of photocoagulation, but the changing of therapeutic sequence might have no dramatic influence on light sensilivity of 5deg;macular threshold.
(Chin J Ocul Fundus Dis,2000,16:150-152)
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 values?of 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.
Purpose
Researching the relared risk factors of diabetic retinopathy (DR) through the epidemiological investigation.
Methods
Basing on a population random sampling survey and screening in 6 areas and cities of Anhui,216 diabetics were screened and they were then investigated in detail by filling in forms,measuring blood pressure,ocular examination including ophthalmoscopy,and lab examination including fasting blood glucose (FBG),blood glucose 2 hours after meal,urine albumin excretion (UAE),serum triglyceride,and cholesterol.
Results
The resultant date revealed that the duration of diabetes,blood pressure FBG and UAE were associated significantly with DR (Plt;0.05),and serum triglyceride and cholesterol were associated not significantly with DR(Pgt;0.05).
Conclusion
Long duration of diabetes,hight FBG and hight blood pressure are the important risk factors of DR,and urine albumin might forebode the occurrence of DR.
(中華眼底病雜志,1998,14:119-121)
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.
