Diabetic retinopathy is a serious complication of diabetes and is the leading cause of blindness in people with diabetes. At present, there are many views on the pathogenesis of diabetic retinopathy, including the changes of retinal microenvironment caused by high glucose, the formation of advanced glycation end products, oxidative stress injury, inflammatory reaction and angiogenesis factor. These mechanisms produce a common pathway that leads to retinal degeneration and microvascular injury in the retina. In recent years, cell regeneration therapy plays an increasingly important role in the process of repairing diseases. Different types of stem cells have neurological and vascular protection for the retina, but the focus of the target is different. It has been reported that stem cells can regulate the retinal microenvironment and protect the retinal nerve cells by paracrine production, and can also reduce immune damage through potential immunoregulation, and can also differentiate into damaged cells by regenerative function. Combined with the above characteristics, stem cells show the potential for the repair of diabetic retinopathy, this stem cell-based regenerative therapy for clinical application provides a pre-based evident. However, in the process of stem cell transplantation, homogeneity of stem cells, cell delivery, effective homing and transplantation to damaged tissue is still a problem of cell therapy.
ObjectiveTo observe the changes of retinal morphology and function of macular-off rhegmatogenous retinal detachment (RRD) after scleral bulking. MethodsIn this prospective study, 42 eyes of 41 patients who underwent scleral bulking were enrolled. There were 26 males (27 eyes) and 15 females (15 eyes), with an average age of (33.78±11.21) years. Best corrected visual acuity (BCVA), intraocular pressure, indirect ophthalmoscope, visual fields, optical coherence tomography (OCT) and B scan of ocular ultrasound were measured for all patients. The average BCVA was 0.29±0.18. The retinal detachment time was (21.12±3.71) days. The mean visual field defect (MD) was (13.54±6.44) dB. The mean loss variance (LV) was (8.43±2.11) dB. All the patients were performed cryotherapy and sub-choroidal fluid drain out. The mean follow-up was 12.4 months (from 6 to 24 months). At two weeks, 1, 3, 6, 12 months after surgery, the changes of BCVA, visual fields, retinal morphology and subretinal fluid were observed. ResultsIndirect ophthalmoscope combined with B scan showed the time of retinal reattachment was (7.32±2.53) days. Subretinal fluid was found completely absorbed by OCT with a mean of (7.82±3.52) months. At 12 months after surgery, subretinal fluid was completely absorbed in 37 eyes (88.10%). In these 37 eyes, 15 eyes had normal retinal microstructure, 5 eyes had neuroepithelial cystoid edema; 12 eyes had disrupted inner segment/outer segment (IS/OS) junction, and 5 eyes had disrupted IS/OS and external limiting membrane (ELM). BCVA at 6 months after surgery was no significant difference with that at 12 months after surgery (t=-0.636, P=0.529). At 12 months after surgery, there were 4 retinal patterns on OCT examination, including normal retinal microstructure, neuroepithelial cystoid edema, IS/OS line disruption, and IS/OS and ELM disruption. The BCVA difference among these 4 groups was significant (F=52.42, P < 0.05). The BCVA difference between eyes with or without residual subretinal fluid was significant (t=-5.747, P=0.000). At 1, 2 weeks and 1, 3, 6, 12 months after surgery, the MD were (11.38±2.53), (10.14±2.19), (9.17±2.13), (6.63±1.70), (5.71±1.89), (5.14±1.69) dB respectively, with a significant difference between these time-points (F=63.528, P=0.00). However, the MD at 6 months after surgery was no significant difference with that at 12 months after surgery (t=1.442, P=0.157). At 12 months after surgery, there were 12 eyes with normal MD, 30 eyes with higher MD. There was no significant difference between surgery eyes with higher MD and fellow eyes in MD (t=-1.936, P=0.06). The MD value was positively correlated to the time of retinal detachment in patients with normal retinal microstructure (r=0.84, P=0.00). There were differences in LV during different periods after surgery (F=57.25, P=0.00). ConclusionsThe retinal microstructure, visual acuity, visual fields were gradually improved after scleral bulking. The patients had better vision with normal retinal microstructure. The time of retinal detachment positively correlated with visual fields damage.
Objective o observe the expression of Notch1 and Delta-like ligand 4 (Dll4) on the fibrovascular membranes in proliferative diabetic retinopathy (PDR), and investigate its relationship with vascular endothelial growth factor receptor 2 (VEGFR2). Methods Fifty-seven PDR patients (60 eyes) who underwent vitrectomy were enrolled in this study. The PDR patients were divided into non-injection group (30 patients, 32 eyes) and injection group (27 patients, 28 eyes). The eyes in injection group received intravitreal injection with ranibizumab at 2 to 7 days before surgery. The preretinal fibrovascular membranes were obtained from the PDR patients during vitrectomy. Eighteen epiretinal membranes were obtained from the non-diabetic patients was served as controls. The real-time polymerase chain reaction (RT-PCR) and immunohistochemical methods were used to detecting the expression of Notch1, Dll4 and VEGFR2. In the meantime, the numbers of the nucleus of vascular endothelial cells in the membranes stained with hematoxylin were counted. Results The immunohistochemical staining revealed that there were positive expression of Notch1, Dll4 and VEGFR2 in all PDR membranes, regardless of the injection of the ranibizumab. The levels of Notch1, Dll4 and VEGFR2 protein in non-injection group were higher than those of injection group (t=3.45, 6.01, 4.08;P=0.030, 0.008, 0.023). In injection group, the number of endothelial cells in the membranes reduced (17.17±2.48) compared with that of the non-injection group (41.50±5.57). There was significant difference in the number of endothelial cells in the membranes between the two groups (t=9.58,P＜0.05). RT-PCR showed that the differences of the mRNA expression of Notch1, Dll4 and VEGFR2 were all statistically significant among the PDR group and control group (H=12.50, 12.50, 12.02;P＜0.05).The expression of Notch1, Dll4 and VEGFR2 in the PDR membranes was higher than that of epiretinal membranes from non-diabetic patients. In the PDR group, the expression of Notch1, Dll4 and VEGFR2 of non-injection group was higher than that of injection group. Spearman correlation analysis showed that the expression of mRNA between VEGFR2 and Dll4 (r=0.83), VEGFR2 and Notch1 (r=0.81), Notch1 and Dll4 (r=0.87) were all significantly correlated (P＜0.05). Conclusions The expression of Notch1 and Dll4 in the PDR membranes are higher than that of the control group, and it is positively correlated with the expression of the VEGFR2. Notch1 and Dll4 play a regulatory rule in the neovascularization in PDR, the acting way may be correlated with VEGFR2.
Objective To observe the effect of netrin-1 on retinal Müller cells in diabetes mellitus (DM) rats. Methods Fifty Sprague-Dawley rats were randomly divided into the normal control group (group A), normal + balanced salt solution (BSS) group (group B), normal+netrin-1 group (group C), DM+BSS group (group D) and DM+netrin-1 group (group E), with 10 rats in each group. DM rats were induced by intraperitoneal injection of Streptozotocin (60 mg/kg). The expression level of glial fibrillary acidic protein (GFAP) on retinal Müller cells was determined by immunohistochemistry, the level of GFAP mRNA was analyzed by real-time fluorescence quantitative reverse transcription polymerase chain reaction. Results Immunohistochemistry showed that GFAP was distributed in retinal ganglion cells and retinal nerve fiber layer in group A, B and C. Compared to group B, GFAP staining was brighter in the group D. There were significant differences in the expression of GFAP protein and mRNA among groups A-E (F=203.43, 72.91; P=0.00, 0.00), they were higher in group D than group A (t=−26.01, 22.26; P=0.00, 0.00), and group E (t=−10.78, 3.93; P=0.00, 0.00). They were higher in group E than group A (t=7.00, −9.82; P=0.00, 0.00). There were no significant differences in between group A and group C (t=−0.29, 0.50; P=0.77, 0.62). Conclusion The expression of GFAP in Müller cells of DM rats could be decreased by injecting netrin-1 into vitreous.
Objective To observe the effect of macular retinal thickness (CMT) on the long-term visual prognosis after intravitreal injection of Conbercept combined with retinal laser photocoagulation for macular edema (ME) secondary to branch retinal vein occlusion (BRVO). Methods A retrospective non randomized controlled study. Forty-one patients (41 eyes) of ischemic BRVO secondary ME were included in the study. Among them, there were 23 males (23 eyes) and 18 females (18 eyes). The average age was (56.49±8.94) years. The best corrected visual acuity (BCVA) and optical coherence tomography were performed. The mean logMAR BCVA was 0.82±0.41, and the mean CMT was (512.61±185.32) μm. According to the CMT reduction value at 1 month after treatment, the eyes were divided into no response group and response group, each has 15 patients of 15 eyes and 26 patients of 26 eyes respectively. The age and sex composition of the two groups were not statistically significant (t=−0.298, −1.708; P=0.767, 0.096), and the difference of frequency of injection was statistically significant (t=3.589, P=0.010), and there was no statistical difference between the patients with logMAR BCVA and CMT (t=2.056, −1.876; P=0.460, 0.070). The average follow-up was 8 months. The logMAR BCVA on 6 months after treatment was defined as long term vision. The changes of long term vision and CMT on 1 and 6 months of two groups after treatment were observed. Pearson correlation analysis showed that the correlation between long-term vision and age, logMAR BCVA before treatment, CMT before treatment, frequency of injection, and CMT value decreased 1 month after treatment. The correlation of long-term visual acuity with age, sex, logMAR BCVA before treatment, CMT before treatment, number of drugs before treatment, CMT reduction at 1 month after treatment, integrity of ellipsoid band and integrity of external membrane (ELM) were analyzed by multiple regression analysis. Results On 1 month after treatment, the CMT of the eyes was lower than that before treatment (231.48±177.99) μm, and the average integrity of ELM and ellipsoid were 0.56±0.50 and 0.41±0.50 respectively. On 6 months after treatment, the average logMAR BVCA of the eyes was 0.48±0.34. The results of Pearson correlation analysis showed that the long-term vision was positively correlated with the logMAR BCVA before treatment and the number of CMT reduction and the number of drug injection at 1 month after treatment (P＜0.05); there was no correlation with age and CMT before treatment (P＞0.05). The results of multiple regression analysis showed that the long-term vision was associated with logMAR BVCA before treatment, CMT reduction, ELM integrity, and the number of times of injection (P＜0.05), and no correlation with age, sex, CMT before treatment and the integrity of the ellipsoid (P＞0.05). On the 6 months after treatment, the logMAR BCVA in the non-response group and the response group were 0.86±0.23 and 0.26±0.14, and the average CMT was respectively (398.93±104.87) and (255.15±55.18) μm, and the average injection times were respectively (2.53±1.46) and (1.31±0.74) times. The average logMAR BCVA, CMT and injection times of the two groups were statistically significant (t=10.293, 5.773, 3.589; P=0.000, 0.000, 0.001). No complications related to drug or intravitreal injection occurred in all patients. Conclusion The long-term vision of ME secondary to BRVO after intravitreal injection of Conbercept combined with retinal laser photocoagulation was associated with the decrease of CMT and the integrity of the ELM after 1 month of treatment, no correlation was found between CMT and ellipsoid integrity before treatment.
ObjectiveTo explore the effect and mechanism of netrin-1 on blood-retinal barrier permeability in diabetes mellitus (DM) rats. MethodsEighty Sprague-Dawley rats were randomly divided into the normal control group, DM+balanced salt solution (BSS) group, DM+netrin-1 low dose group and DM+netrin-1 high dose group, with 20 rats in each group. DM rats were induced by intraperitoneal injection of streptozocin (STZ). These rats were feed with high sugar and fat for 3 months after STZ injection. All rats were sacrificed at 1 month after intravitreal injection. Retinal vascular permeability was measured by Evans blue. The expression level of occludin was determined by immunohistochemistry. Hematoxylin-eosin (HE) staining of retina was used to observe the pathological change of DM and the level of occludin mRNA was analyzed by real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-PCR). Five rats of each group. ResultsHE staining of retina showed that the degree of edema and vascularization in DM+netrin-1 high dose group was better than DM+BSS group. Staining of occludin in retina was limited to nerve fiber layer, ganglion cells, inner plexiform layer and inner nuclear layer in normal rats, but in DM+BSS group, the color of staining positive of occludin was lighter and more reduced. However, DM+ netrin-1 group occludin staining was deepen and enlarged. The result of RT-PCR showed that the expression of occludin mRNA in other three groups was less than normal control group (P < 0.05). The significant difference during DM+BSS group, low dose group and DM+netrin-1 high dose group (F=177.13, P=0.00), and the more concentrate of netrin-1 the higher expression of occluding. Compared the DM+netrin-1 low dose group with DM+BSS group, there was significant difference expression of occludin (t=-13.98, P=0.00). There was significant difference between the DM+netrin-1 high dose group and normal control group (t=12.87, P=0.00). There was statistically significant difference in DM+BSS group, DM+netrin-1 low dose group and DM+netrin-1 high dose group (F=179.69, P=0.00). Compared the two group of different concentration netrin-1, the quantification of vascular permeability in DM+netrin-1 high dose group reduced more (t=12.73, P=0.00). ConclusionsNetrin-1 can protect the blood-retinal barrier in DM rats. Netrin-1 may decrease BRB leakage in DM rats by protecting the expression of occludin.
Objective To observe the efficacy of intravitreal injection of ranibizumab (IVR) for different patterns of optical coherence tomography (OCT) of diabetic macular edema and the relationship between integrity of ellipsoidal zone and visual acuity outcomes. Methods Eighty-five IVR treated eyes were enrolled. The examination of BCVA was according to Early Treatment Diabetic Retinopathy Study, and the results were recorded as logarithm of the minimum angle of resolution (logMAR). Frequency-domain OCT was used to measure the central foveal thickness (CFT) and the integrity of ellipsoidal zone. All eyes were classified as diffuse macular edema (DRT group, 31 eyes), cystoid macular edema (CME group, 29 eyes), and serous retinal detachment (SRD group, 25 eyes). All the patients were treated with intravitreal injection of 0.05 ml (0.5 mg) ranibizumab. The mean follow-up time was (9.21+3.56) months after IVR treatment. The changes of BCVA and CFT in 3 groups were compared and analyzed after 3, 6 and 12 months. According to visual acuity at different ranges, the relationship between integrity of ellipsoidal zone and BCVA was analyzed. Results Compared with the average logMAR BCVA before treatment, except for 12 months after treatment in group SRD (t=2.104,P=0.053), the average logMAR BCVA after IVR at 3 months, 6 months and 12 months improved in DRT group (t=7.847, 6.771, 6.426;P=0.000, 0.000, 0.000), CME group (t=8.560, 6.680, 5.082;P=0.000, 0.000, 0.000) and SRD group (t=5.161, 3.968, 2.104;P=0.000, 0.001, 0.053). The average logMAR BCVA of the DRT group was lesser than that in CME and SRD group after 12 months treatment (t=–2.043, –3.434;P=0.030, 0.001). The average CFT after IVR at 3 months, 6 months and 12 months reduced significantly in DRT group (t=12.746, 10.687, 9.425;P=0.000, 0.000, 0.000), CME group (t=13.400, 11.460, 10.169;P=0.000, 0.000, 0.000), and SRD group (t=11.755, 10.100, 9.173;P=0.000, 0.000, 0.000). After 12 months of treatment, the average CFT of the SRD group was thicker than that in DRT group and CME group (t=–3.251, –1.227;P=0.003, 0.025); there was significant difference in the integrity of ellipsoidal zone among 3 groups (χ2=1.267,P=0.531). The results showed that there were significant differences in the integrity of ellipsoidal zone with different ranges of BCVA before and after 12 months treatment (χ2=20.145, 41.035;P=0.000, 0.000). Conclusions IVR could significantly improve the visual acuity of different patterns of DME, reduced the CFT, and had the best efficacy in the DRT group. There was relationship between the integrity of ellipsoidal zone and the visual acuity outcomes.
Objective To observe the effect of different concentration netrin-1 on retinal vascular permeability in diabetes mellitus (DM) rats. Methods Eighty adult Sprague-Dawley rats were randomly divided into 8 groups, 10 rats in each group, including normal control group (group A), normal＋balanced salt solution (BSS) group (group B), normal＋netrin-1 (500 μg/ml) group (group C) and DM group (50 rats in 5 sub-groups). DM rats were induced by intraperitoneal injection of streptozocin. Three months after intraperitoneal injection, 10 DM rats in the control group were injected with BSS (group D). Forty DM rats were injected with 5 μl of different concentrate netrin-1, and were divided into DM+netrin-1 10 μg/ml group (group E), DM+netrin-1 50 μg/ml group (group F), DM＋netrin-1 100 μg/ml group (group G), DM＋netrin-1 500 μg/ml group (group H) according to the different concentration. Non-DM rats in group C were injected with netrin-1 500 μg/ml. The expression of occludin was determined by immunohistochemistry for protein, and by real-time fluorescence quantitative reverse transcription polymerase chain reaction for mRNA level. Retinal vascular permeability was measured by Evans blue infusion. Results The expression of occludin protein and mRNA in group D were less than group A (t=27.71, 8.59;P=0.00, 0.00). However, the retinal vascular permeability increased in group D (t=−42.72,P=0.00). The expression of occluding protein, occludin mRNA and retinal vascular permeability showed significant differences between group D, E, F, G and H (F=146.31, 16.54, 67.77;P=0.00, 0.00, 0.00). Compared the group B with group C, there was no significant differences between the expression of occludin protein, occludin mRNA and the retinal vascular permeability (t=−1.13, 0.93, 1.04;P=0.27, 0.36, 0.31). The concentrate of netrin-1 showed a significant positive correlation to the expression level of occludin and occludin mRNA (r=0.73, 0.81;P=0.00, 0.00), but negative correlation to the vascular permeability (r=−0.61,P=0.00). Conclusion Netrin-1 can reduce the DM rats' retinal vascular permeability, which depended on the concentration of netrin-1.
ObjectiveTo observe and investigate the effect of HIF-2α in the process of neovascularization of proliferative diabetic retinopathy (PDR).MethodsRetrospective clinical study. From July 2014 to July 2015, 60 eyes of 57 PDR patients diagnosed in Ophthalmology Department of Affiliated Hospital of Qingdao University were included in the study. Twenty-eight eyes of 27 patients received intravitreal injections of 0.5 mg ranibizumab (0.05 ml) at 2-7 days before surgery (ranibizumab group) and other 32 eyes of 30 patients did not (group without ranibizumab). Eighteen eyes of 18 patients with epiretinal membranes were included as controls. Pathological specimens of PDR fibrovascular membrane and premacular membrane were obtained during vitrectomy. The immunohistochemical staining and real-time PCR (RT-PCR) were used to detecting the expression of HIF-2α, Dll4 and VEGF. Kruskal-wallis test was used to compare the expression differences of correlation factors between groups. Spearman correlation analysis was used to analyze the relationship between the two variables.ResultsThe immunohistochemical staining revealed that there were positive expression of HIF-2α, Dll4 and VEGF in all PDR membranes, regardless of the injection of the ranibizumab. The levels of HIF-2α, Dll4 and VEGF protein in the group without ranibizumab were higher than those of the ranibizumab group (t=4.36, 6.01, 4.82; P=0.000, 0.008, 0.016). RT-PCR showed that the differences of the mRNA expression of HIF-2α, Dll4 and VEGF were all statistically significant among the PDR patients and controls (H=18.81,19.60, 20.50; P=0.000, 0.000, 0.000). The expression of HIF-2α, Dll4 and VEGF in the PDR membranes was higher than that of epiretinal membranes from non-diabetic patients. In the PDR patients,the expression of HIF-2α, Dll4 and VEGF of the group without ranibizumab was higher than that of the ranibizumab group. The spearman correlation analysis showed that the expression of mRNA between HIF-2α and Dll4, HIF-2α and VEGF were both significantly correlated (r=0.95, 0.87; P＜0.05).ConclusionsThe expression of HIF-2α in the PDR membranes was higher than that of the controls. It is positively correlated with the expression of the DLL4 and VEGF.