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 investigate the value of psychophysical testing for the macular function in the diegnosis of diabetic retinopathy(DR). METHODS:To compare the testing results of macular light sensitivity and pattern visual evoked potential(P-VEP)of 30 eyes of 15 normal person with those of 82 eyes of 41 diabetic patients(27 eyes without DR,55 eyes with simple type DR ). RESULTS:The macular light sensitivity of diabetic patients is much lower than that of normal Control group(plt;0.05). In the diabetic group, 62.19% is abnormal in macular light sensitivity, 69.51% in P-VEP. CONCLUSION: Testing of macular light sensitivit y is helpful in finding of diabetic retinopathy and early deterioration of macular visual function in diabetics. （Chin J Ocul Fundus Dis,1996,12: 223-224）
Objective To study the relationship between central retinal thickness and retinal vascular filling state of patients with non-proliferative diabetic retinopathy (NPDR). Methods A total of 248 diabetic patients without retinopathy or with NPDR in the hospital were enrolled in the study. Only the right eye of these patients were examined by optical coherence tomography (OCT), fundus fluorescein angiography (FFA), color Doppler flow imaging (CDFI). Patients with central retinal edema, hemorrhage and exudation were excluded from this study. Central retinal thickness was measured by OCT at the points of 1 mm, 1 to 3 mm, and 3 to 6 mm from the fovea. The patients were divided into retinal thickness normal, thinning and thickening groups according to their central retinal thickness. The normal range of central retinal thickness was defined as 216.4-304.9 μm in this study. The arm retinal circulation time and retinal arterial phase and venous phase (A-V) fluorescence filling time were recorded by FFA examination. The peak systolic velocity (PSV), pulsatility index (PI) and resistance index (RI) of ophthalmic artery (OA), central retinal artery (CRA) and posterior ciliary artery (PCA) were measured by CDFI examination. The retinal fundus vascular filling state and ocular hemodynamic indexes were compared between different groups. Results The arm retinal circulation time of retinal thickness normal, thinning, thickening groups was (10.42±0.51), (10.36±0.64), (12.94±0.46) seconds respectively; the retinal A-V fluorescence filling time was (9.15±1.36), (6.36±1.15), (13.56±2.04) seconds. The difference of the arm retinal circulation time was statistically significant between the thickening and normal groups (t=1.93,P=0.04), and between the thickening and thinning groups (t=4.49,P=0.00). The retinal A-V fluorescence filling time was statistically significant between the thinning and normal groups (t=2.13,P=0.03), and between the thickening and normal groups (t=2.49,P=0.02), and between the thickening and thinning groups (t=5.38,P=0.00).The difference of PSV (t=3.290, -5.520, -4.900), PI (t=-4.310,-5.230, -4.390) and RI (t=4.970, 6.160, 5.990) of OA, CRA and PCA was statistically significant between the thickening and thinning groups (P＜0.05). Conclusion Central retinal thickness can affect the retinal vascular filling state of diabetic patients without retinopathy or with NPDR.
OBJECTIVE:To investigate relationship between plasma endotbelin(ET)and serum angiotensin converting enzyme (ACE)levels and diabetic retinopathy (DR). METHODS: Plasma ET and serum ACE levels were measured in 62 patients with diabetes mellitus(DM) and in 30 normal control subjects with radioimmunoassay and ultraviolet-spectrophotometry. RESULTS:Plasma ET and serum ACE levels in patients with DR were significantly higher than in patients without DR (P＜0.01). Along with the progression of DR,plasma ET levels were significantly elevated and serum ACE levels were gradually elevated. CONCLUSIONS :These findings suggest that increased plasma ET and serum ACE levels may be related to the development and progression of DR. （Chin J Ocul Fundus Dis,1996,12: 177-179）
ObjectiveTo observe the effect of Delta-like ligand 4 (Dll-4) on the pathological structure of retina in early diabetic rats (DM) and its relationship with vascular endothelial growth receptor-2 (VEGFR-2).MethodsA total of 70 male Sprague-Dawley rats were randomly divided into normal group and DM group, with 10 and 60 rats in each group, respectively. The rats of DM group was induced by intraperitoneal injection of streptozotocin to established DM model. The rats with blood glucose recovery and death were excluded, and the final 60 rats were included in the statistics. Rats in the normal group were injected with an equal volume of citric acid-sodium citrate buffer. Rats in the DM group were divided into DM 1 month (DM 1m) group, DM 2 months (DM 2m) group, DM 3 months (DM 3m) group and DM 3m + Anti group, DM 3m + phosphate buffer solution (PBS) group by random number table method, and 10 rats in each group. In the DM 3m+Anti group, 4 μl of anti-Dll-4 polyclonal antibody was injected into the vitreous cavity, and the antibody concentration was 0.25 mg/ml. The DM 3m+PBS group was intravitreally injected with an equal volume of PBS. Five days after the injection, the rats were sacrificed. Rats in the DM 3m group and the normal group were not treated, and were sacrificed 3 months after the model was established. The structure and microvascular changes of the retina were observed by hematoxylin-eosin staining, and the total thickness of the retina was measured. The expression of Dll-4 and VEGFR-2 in the retina was detected by immunohistochemistry and fluorescence quantitative polymerase chain reaction (PCR). One-way analysis of variance was used to compare the expression of Dll-4 and VEGFR-2 in the retina of each group. The least significant difference t test was used to compare the two groups.ResultsLight microscopy showed that the retinal ganglion cells layer in the DM 3m group were obviously edematous, the inner and outer nuclear layers were thinner, the number of cells was reduced, the arrangement was disordered, the edema of outer plexiform layer was obvious, and the microvessels were abnormally dilated. In the DM 3m+Anti group, the edema of outer plexiform layer was lessened than that of the DM 3m group, and the other layers were not significantly different from the DM 3m group. Compared with the normal group, the total retinal thickness of the DM 3m group, the DM 3m+Anti group and the DM 3m+PBS group increased (t=5.596, 3.290, 4.286; P=0.000, 0.008, 0.002). Immunohistochemical staining showed that a small amount of Dll4 was positively expressed in the retinal ganglion cell layer of the normal group; a small amount of VEGFR-2 was positively expressed in the ganglion cell layer and the inner and outer nuclear layers. The positive expression of Dll-4 and VEGFR-2 in retinal vascular endothelial cells of DM 3m group increased significantly. The expression of Dll-4 was significantly decreased in the retinal layers and vascular endothelial cells of DM 3m+Anti group, while the expression of VEGFR-2 was significantly increased. There was no significant difference between the positive expression of Dll4 and VEGFR-2 in the DM 3m+PBS group and the DM 3m group. The results of real-time PCR showed that the relative expression of Dll-4 and VEGFR-2 mRNA in the DM 3m group was significantly higher than that in the normal group (t=6.705, 20.871; P＜0.05). Compared with DM 3m group, the relative expression of Dll-4 mRNA in DM 3m+Anti group decreased, and the relative expression of VEGFR-2 mRNA increased (t=2.681, 3.639;P＜0.05). The relative expressions of Dll-4 and VEGFR-2 mRNA in the DM 3m+PBS group and DM 3m group were not statistically significant (t=0.513, 0.657; P＜0.05).ConclusionsThe expression of Dll-4 in retinal vascular endothelial cells is gradually increased during the early retinopathy of DM rats. The expression of Dll-4 is inhibited, the expression of VEGFR-2 is up-regulated, and the plexus edema is alleviated.
Objective To observe and preliminarily explore the effects of Deferasirox (DFX) on lipid peroxidation and ferroptosis in human retinal endothelial cells (HREC). MethodsA cell experimental study. Divided the in vitro cultured HREC into normal glucose (NG) group, high glucose (HG) group, NG+DFX group, HG+DFX group, NG+DFX+ferric ammonium citrate (FAC) group, and HG+DFX+FAC group. Light microscope was used to observe the morphology of the cells; cell proliferation was detected by Cell Counting Kit-8 assay, and Calcein-AM staining was used to detect the unstable iron pool (LIP) content; enzyme-linked immunosorbent assay reader was used to detect the reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), and oxidized glutathione (GSSG); Western blot was used to detect the relative protein expression of Glutathione Peroxidase 4 (GPX4) and Solute Carrier Family 7 Member 11 (SLC7A11). Two-tailed Student t test was used for comparison between the two groups; one-way ANOVA was used for comparison between multiple groups. ResultsCompared with the HG group and the HG+DFX+FAC group, the cell proliferation rate and the contents of GSH and the relative protein expression of GPX4, and SLC7A11 in the HG+DFX group were significantly increased, and the differences were statistically significant (F=150.70, 21.02, 26.09, 52.62; P＜0.001). The contents of LIP, ROS, MDA, and GSSG were significantly decreased, and the differences were statistically significant (F=807.20, 16.94, 31.62, 19.21; P＜0.001). ConclusionsHigh glucose significantly induces an increase in LIP, lipid peroxidation, and ferroptosis in HREC. Deferasirox inhibits lipid peroxidation and ferroptosis in HREC by downregulating LIP levels.
ObjectiveTo compare the effects of intravitreal tamponade of C3F8 with silicon oil on postoperative vitreous hemorrhage and visual prognosis after vitrectomy for proliferative diabetic retinopathy (PDR). MethodsThe clinical data of 121 patients (127 eyes) who underwent primary vitrectomy due to PDR were analyzed retrospectively. All the patients were divided into two groups according to different intravitreal tamponade, including C3F8 tamponade group (53 patients with 56 eyes) and silicone oil tamponade group (68 patients with 71 eyes). There was no difference of gender (χ2=0.956), age (t=1.122), duratiion of diabetes (t=0.627), fasting blood glucose (t=1.049), systolic pressure (t=1.056), diastolic pressure (t=0.517), history of hypertension (χ2=0.356), nephropathy (χ2=1.242), preoperative laser photocoagulation (χ2=1.225) and All the patients underwent three port pars plana vitrectomy. The mean follow-up was 2 years ranging from 6 months to 4 years. And then the incidence and onset time of postoperative vitreous hemorrhage and postoperative BCVA of the two groups were compared. ResultsPostoperative vitreous hemorrhage occurred in 14 of 56 eyes (25.00%) in C3F8 tamponade group. The average onset time of postoperative vitreous hemorrhage were (64.64±59.09) days ranging from 7-225 days and mostly were within 30-60 days (35.71%, 5/14). Postoperative vitreous hemorrhage also occurred in 7 of 71 eyes (9.89%) of silicone oil tamponade group after silicone oil removal with an average onset time of (25.29±20.46) days ranging from 3-65 days and were mostly within 15-30 days (42.86%, 3/7). There was a significant difference in the incidence of postoperative vitreous hemorrhage between the two groups (χ2=5.200, P<0.05). BCVA of the two groups was improved significantly after operation (Z=2.472, 3.114; P<0.05). Postoperative BCVA of silicone oil tamponade group was poorer than C3F8 tamponade group (Z=1.968, P<0.05). ConclusionBoth C3F8 and silicone oil tamponade can improve the visual acuity after vitrectomy for PDR. Compared with C3F8, silicone oil tamponade had lower incidence and late onset of postoperative vitreous hemorrhage after vitrectomy for PDR.
Objective To investigate the effects of advanced glycation endproducts (AGEs) on proliferation of pericytes of bovine retinal capillary vessels and expression of transforming growth factor beta;(TGF-beta;). Methods The proliferation of pericytes detected by methyl thiazolyl tetrazolium (MTT) colorimetric assay, cellular cycle of pericytes was analyzed by flow cytometry was used to analyze cell, and TGF-beta; protein expression of pericytes was observed by immunofluorescent staining. Results AGEs inhibited the proliferation of pericytes of bovine retinal capillary vessels, stopped the cellular cycle of pericytes in synthesis phase (S phase), increased the number of apoptotic cells obviously (Plt;0.01), and promoted the expression of TGF-beta; proteinof perycytes. Conclusions AGEs may promote the apoptosis of pericytes by inhibiting the proliferation of pericytes to lead the decrease of pericytes number, and may accelerate diabetic retinopathy by promoting the expression of TGF-beta; protein of pericytes. (Chin J Ocul Fundus Dis, 2006, 22: 20-23)
Objective To investigate the effect of the damage and functional change of vascular endothelial cells (VEC) on diabetic retinopathy(DR). Methods Circulating endothelial cell (CEC) number and plasma endothelin(ET) level were measured in 18 normal control subjects and 55 patients with diabetes mellitus (DM) consisting of 20 cases of DM with out retinopathy,20 cases of DM with-background diabetic retinopathy and 15 cases of DM with proliferative diabetic retinopathy. Results CEC number and plasma ET level in DM were significantly higher than those in normal subjects(Plt;0.001)respectively.With the progression of DR,CEC number was significantly elevated and plasma ET level was gradually elevated.There was significant positive correlation between CEC number and plasma ET level (r=0.738,Plt;0.001,n=55). Conclusion VEC damage and elevated plasma ET level induced by VEC damage may play an important role in the development and progression of DR. (Chin J Ocul Fundus Dis,2000,16:166-168)
ObjectiveTo investigate the effect of intravitreal injection of neural stem cells (NSC) derived from human umbilical cord mesenchymal stem cells (hUCMSC) on the expression of brain-derived neurotrophic factor (BDNF) and the number of retinal ganglion cells (RGC). MethodsFifty-two adult male Sprague-Dawley rats were randomly divided into normal group (group A) and diabetes mellitus group which received intraperitoneal injection of streptozocin to make diabetic rat models. One month after the diabetic rat models were confirmed successfully, diabetic rats were randomly divided into diabetic group (group B), hUCMSC group (group C) and hUCMSC-induced NSC group (group D). And thirteen diabetic rats were included in each group. Immuno-cytochemistry was applied to observe BDNF and thymosin-1(Thy-1) staining in the retina. Then mean integrated absorbance of the staining region on the retina slices were analyzed by Image-Pro Plus 6.0. The number of Thy-1 labeled RGC was record. ResultsBDNF and Thy-1 were positive on the retina slices from group A. The staining intensity from group B became weak and the expression of BDNF and Thy-1 gradually decrease with time (P < 0.05), and those from group C and group D were positively (P < 0.05), especially in group D (P < 0.05). The BDNF expression and Thy-1 labeled RGC were the same between group B and C (P > 0.05) at 2 weeks after injection, but were significant different for other time points (P < 0.05).Significant positive correlation between the expression of BDNF and the number of RGC were found by the Pearson correlation analysis (r=0.964, P < 0.05). ConclusionIntravitreal injection of hUCMSC-derived NSC to diabetic rat may protect the retina by promoting the expression of BDNF and increasing the number of RGC.