Dysregulation and activation of immune processes are important in age-related macular degeneration (AMD) pathogenesis. The single nucleotide polymorphism of complement factor H is widely recognized as a risk factor to AMD. Over-activation of nod-like receptor3 and polymorphism of Toll-Like Receptor 3 also associated with AMD. Except for innate immune processes, adaptive immunity also play a critical role in AMD, a growing body of evidence supports that auto-antibodies and T cells are related with AMD. Additionally A2E and lipid oxidation byproducts might also have a role in AMD pathogenesis.
Mesenchymal stem cells (MSC) are considered to have important value in the treatment of various diseases because of their low immunogenicity, transferability, and strong tissue repair capacity. Stromal cell derived factor-1 (SDF-1) and its receptor CXC chemokine receptor 4 (CXCR4) pathway plays an important role in migration of MSC. The induction of homing of MSC to retina by regulating SDF-1/CXCR4 may exert the curative effect on diabetic retinopathy to greatest exent.
Diabetic retinopathy (DR) isacommon cause of blindness, its occurrence and development are the synergic results of multiple factors. Current studies suggest that inflammation and inflammatory factor has an important role in the pathogenesis of DR. The occurrence and development of DR are closely related with interleukins, intercellular adhesion molecules, hasten factors, tumor necrosis factor, C-reactive protein etc. Mesenchymal stem cells (MSCs) are pluripotent cells derived from the mesoderm and have multiple differentiation potentials, and anti-inflammatory and immunosuppressive function. Recent studies shown that MSCs transplantation can protect damaged retina by inflammatory regulation, which becomeanew research direction for DR treatment.
ObjectiveTo observe the effects of human umbilical cord mesenchymal stem cells (hUCMSCs) on blood glucose levels and diabetic retinopathy in diabetes mellitus (DM) rats. MethodA total of 45 healthy male Sprague-Dawley rats were randomly divided into normal control group (group A, 10 rats) and DM group (33 rats). Diabetic model was established in DM group by tail vein injection of streptozotocin.The DM group was further randomly divided into 3 groups (11 rats in each group), including group B (no transplantation), group C (hUCMSC was injected through tail vein) and group D (hUCMSC was injected into the vitreous). Blood glucose, retina wholemont staining and expression of brain derived neurotrophic factor (BDNF) in the retina were measured at 2, 4, 6, 8 weeks after hUCMSC injection. The blood glucose was significantly different between A-D groups before injection (t=-64.400, -60.601, -44.065, -43.872; P=0.000) BDNF expression was studied by real time fluorescence quantitative polymerase chain reaction (RT-PCR) and immunohistochemistry staining. ResultsThe blood glucose was significantly different between A-D groups after hUCMSC injection (F=400.017, 404.410, 422.043, 344.109; P=0.000), and between group C and group B/D (t=4.447, 4.990; P < 0.01). Immuno-staining shown that BDNF was positive in ganglion cell layer (RGC) of group A, weak in group B while BDNF expression increased in group C/D. BDNF mRNA expression was significantly different between group B, C and D at 4, 6 and 8 weeks after hUCMSC injection (F=29.372, 188.492, 421.537; P=0.000), and between group B and C/D (t=66.781, 72.401, 63.880, 88.423, 75.120, 83.002; P < 0.01) by RT-PCR analysis. The BDNF mRNA expression was significantly different between C and D groups only at 8 weeks after hUCMSC injection (t=127.321, P=0.005). ConclusionsTail vein injection of hUCMSCs can significantly reduce the blood glucose levels of rats. Intravenous and intravitreal injection of hUCMSCs can increase the expression of BDNF.
ObjectiveTo observe the clinical effect of microincision vitreoretinal surgery (VRS) assisted with intravitreal injection of ranibizumab (IVR) in severe proliferative diabetic retinopathy (PDR) treatment. MethodsThis is a prospective non-randomized controlled clinical study. A total of 60 patients (70 eyes) with severe PDR diagnosed were enrolled and divided into IVR group (31 patients, 35 eyes) and control group (29 patients, 35 eyes). IVR group patients received an intravitreal injection of 0.05 ml ranibizumab solution (10 mg/ml) first, and 3 or 4 days later they received 23G microincision VRS. Control group patients only received 23G microincision VRS. The follow-up time was 3 to 12 months with an average of (4.5±1.8) months. The logarithm of the minimal angle of resolution (logMAR) best corrected visual acuity (BCVA), intraocular pressure, the central retinal thickness (CRT) and retinal reattachment, and the incidence of postoperative complications were comparatively analyzed. ResultsThere was no topical and systemic adverse reactions associated with the drug after injection in IVR group. The incidence of post-operative vitreous hemorrhage (VH) in IVR group and control group was 8.6% and 28.6% at 1 week after surgery, 0.0% and 17.1% at 1 month after surgery, 0.0% and 8.6% at 3 month after surgery respectively. The differences were statistically significant for 1 week (χ2=4.63, P < 0.05) and 1 month (χ2=4.56, P < 0.05), but was not statistically significant for 3 months (χ2=0.24, P > 0.05). The mean post-operative logMAR BCVA of IVR group (0.81±0.40) and control group (1.05±0.42) have all improved than their pre-operative BCVA, the difference was statistically significant (t=12.78, 4.39; P < 0.05). The mean logMAR BCVA of IVR group is higher than BCVA of control group, the difference was statistically significant (t=-2.36, P < 0.05). The average post-operative CRT in IVR group was thinner than that of control group, the difference was statistically significant (t=-2.53, P < 0.05). The incidence of a transient high intraocular pressure in IVR group (14.3%) was lower than that in control group (34.3%), the difference was statistically significant (t=4.79, P < 0.05). The incidence of retinal reattachment (t=0.35), epiretinal membrane (χ2=0.97), neovascular glaucoma (χ2=0.51) was no difference between these two groups (P > 0.05). ConclusionThe minimally invasive VRS assisted by IVR treatment for severe PDR can effectively prevent postoperative VH, reduce CRT and improve visual acuity.
Objective To observe the morphological changes of macular capillary in type 2 diabetic mellitus (DM) patients without clinical features of diabetic retinopathy (DR) by optical coherence tomography angiography (OCTA). Methods This is a prospective clinical case-control study. Forty-three eyes of 22 patients with DM without clinical features of DR (case group) and 40 control eyes of 20 age- and sex-matched healthy physical examination subjects (control group) were enrolled in this study. All subjects underwent OCTA examination with mode of retinal blood flow imaging, macular 3 mm×3 mm and 6 mm×6 mm area, signal strength ＞45. Foveal avascular zone (FAZ) area, foveal capillary density, parafovea capillary non-perfusion, and micro-aneurysm in shallow capillary vessel layer were evaluated. Results In case group, the mean FAZ area was (0.397±0.141) mm2 and the mean foveal capillary density was (44.6±0.62) %. In control group, the mean FAZ area was (0.253±0.112) mm2 and the mean foveal capillary density was (48.6±0.58) %. FAZ area of eyes in case group was larger than that in control group (t=1.017,P＜0.05). There was no difference of foveal capillary density between two groups (t=1.499,P＞0.05). The spider web-like FAZ and normal foveolar avascular zone were observed in eyes of control group. The parafovea capillary non-perfusion, abnormal foveolar avascular zone, micro-aneurysm and tortuosity of vessels were observed in eyes of case group. Parafovea capillary non-perfusion (χ2=4.542), micro-aneurysms (χ2=5.183) were seen more often in case group than control group (P＜0.05). Conclusion Type 2 DM patients have abnormal retinal vascular microcirculation before DR using OCTA, including larger FAZ area, parafovea capillary non-perfusion, abnormal foveolar avascular zone, micro-aneurysm and tortuosity of vessels.
Objective To investigate the effects of exosomes from cultured human retinal pigment epithelium (ARPE-19) cells affected by oxidative stress on the proliferation and expression of vascular endothelial growth factor-A (VEGF-A) and Akt of ARPE-19 cells. Methods Culture ARPE-19 cells. The concentration of 2.5 μmol/L rotenone was selected to simulate oxidative stress and isolated ARPE-19-exosome. Exosomes were isolated by ExoQuick exosome precipitation solution. Transmission electron microscopy was used to identify the morphology of exosomes. Western blot was used to detect exosomes’ surface-specific maker protein CD63. ARPE-19 cells affected by oxidative stress were cultured with exosome as experimental group, normal ARPE-19 cells were cultured with exosome as control group. The cell proliferation was examined by methyl thiazolyl tetrazolium assay. Western blot and immunofluorescence assay were used to detect the expression levels of VEGF-A and Akt protein. Real-time quantitative polymerase chain reaction (RT-PCR) was used to detect the levels of VEGF-A mRNA and Akt mRNA. Results The diameter of normal ARPE-19-exosomes ranged from 50 to 150 nm. The isolated exosomes expressed CD63. AREP-19 cells were cultured with ARPE-19 (affected by rotenone)-exosome, the cell viability in experimental group was significantly reduced than in the control group. Green fluorescence was observed in the cytoplasm under fluorescence microscope. Compared with the control group, VEGF-A was up-regulated expressed and Akt was down-regulated expressed. Western blot results showed that, VEGF-A protein expression in the experimental group were higher than the control group. Akt protein expression in the experimental group were less than the control group. The difference was statically significant (t=3.822, 6.527;P＜0.05). RT-PCR results showed that VEGF-A mRNA expression levels was higher in the experimental group than the control group. Akt mRNA expression levels was lower in the experimental group than the control group. The difference was statically significant (t=8.805, −7.823;P＜0.05). Conclusions Exosomes from ARPE-19 cells affected by oxidative stress inhibit the proliferation of normal ARPE-19 cells, increase the expression of VEGF-A and reduce the expression of Akt.
ObjectiveTo observe the immunological regulation effects of human umbilical cord mesenchymal stem cells (hUCMSC) on glucose-damaged rhesus retinal vascular endothelial cells (RF/6A). MethodshUCMSC and RF/6A were co-culture according to 1:1 ratio in the co-culture system (Transwell plates), hUCMSC cells were added to upper chamber, while the lower chamber containing 25mmol/L glucose and RF/6A. There were three groups including RF/6A blank control group, high glucose treated RF/6A group, and high glucose treated RF/6A with hUCMSC co-culture group. MTT was used to measure the RF/6A cell viability. Western blot was used to to detect protein level of Foxp3. Enzyme-linked immunosorbent assay (ELISA) was used to detect the concentration of interleukin (IL)-17. ResultsMTT assay revealed that at the first day, the survival rate of the three groups had no significant difference (F=0.030, P > 0.05). On day 3 and day 7, the cell viability of the high glucose group was significantly lower than that of the control group (t=36.072, 27.890; P < 0.05), the cell viability of the high glucose treated RF/6A with hUCMSC co-culture group was higher than that of high glucose group (t=36.072, 19.650; P < 0.05).Western blot analysis showed that Foxp3 in high glucose RF/6A group was significantly lower than that in the control group at day 7 after culture (t=7.826, P < 0.05) and high glucose RF/6A with hUCMSC group (t=19.936, P < 0.05). ELISA showed that IL-17 in the high glucose group, high glucose with hUCMSC co-culture group was significantly higher than that of the control group (F=1 267.503, P < 0.05), while IL-17 in the hUCMSC co-culture group was significantly lower than that in high glucose group (t=17.386, P < 0.05). ConclusionhUCMSC can regulate the expression of Foxp3 and IL-17 to increase the proliferative ability of RF/6A, which was suppressed by high glucose.
ObjectiveTo observe the effect of exosomes derived from human umbilical cord blood mesenchymal stem cells (hUCMSC) on the expression of vascular endothelial growth factor (VEGF) A in blue light injured human retinal pigment epithelial (RPE) cells. MethodshUCMSC were cultured with exo-free fetal bovine serum for 48 hours, and then the supernatants were collected to isolate and purify exosomes by gradient ultracentrifugation method. Transmission electron microscopy was used to identify the morphology of exosomes. Surface specific maker protein CD63 and CD90 were detected via Western blot. Cultured ARPE-19 cells were divided into normal control group, blue light injured group and hUCMSC exosomes treated group. Cells were exposed to the blue light at the intensity of (2000±500) Lux for 12 hours to establish the light injured models. The cells of hUCMSC exosomes treated group were treated by different concentrations of exosomes for 8, 16, 24 hours. The mRNA and protein of VEGF-A were determined by real time-polymerase chain reaction and Western blot. Immunofluorescence assay were used to detect the expression levels of VEGF-A. ResultshUCMSC exosomes were successfully isolated, they exhibited round or oval shape and their diameter ranged from 50 to 100 nm with membrane structure through electron microscope. hUCMSC exosomes expressed the common surface marker protein CD63 and the surface marker protein CD90 of hUCMSC. The protein and mRNA level of VEGF A in the blue light injured group increased significantly compared to that in normal control group (t=-16.553, -19.456; P < 0.05). After treating with low, middle and high concentration of hUCMSC exosomes for 8, 16 and 24 hours, the protein and mRNA level of VEGF A of injured RPE were significantly decreased (P < 0.05). With the treated time and concentration of hUCMSC exosomes improved, the protein and mRNA level of VEGF A of injured RPE gradually decreased (P < 0.05). Immunofluorescence assay showed the protein level of VEGF-A of injured RPE gradually decreased with the same concentration of hUCMSC exosomes treated over time. ConclusionhUCMSC exosomes can effectively down-regulate the mRNA and protein level of VEGF-A in blue light injured RPE, the effect depends on the concentration and treated time of hUCMSC exosomes.
ObjectiveTo observe the effects on the function and structure of retina in diabetic rats by intravitreal transplantation of retinal nerve stem cells (NSC) differentiated from human umbilical cord mesenchymal stem cells (hUCMSCs). MethodsFifty clean male Sprague-Dawley rats were randomly divided into normal control with 9 rats (group A) and diabetes mellitus (DM) group with 31 rats. The DM models were induced by intraperitoneal injection of streptozocin. The rats of DM group were randomly divided into four groups after 10 weeks: rats with DM only (group B), diabetic rats with saline intravitreal injection (group C), diabetic rats with NSC intravitreal injection (group D), and 9 rats for each. The rats in the group A and B received no treatment. The retinal function was examined by the flash-electroretinogram on 2, 4, 6 weeks after intervention, the latency and amplitude of a-wave, b-wave of Rod, a-wave, b-wave of Max reactions (Max-R) and the total amplitudes of OPs were recorded. The morphological changes of retina were observed by hematoxylin-eosin staining. ResultsOn 2 and 4 weeks after the intervention, the differences of latency and amplitude of b-wave of Rod, a-wave, b-wave of Max-R and the total amplitudes of OPs among group A-D were significant (P<0.05). Compared group D with group B, C, the amplitude of b-wave of Rod, Max-R and the total amplitudes of OPs were increased (P<0.05); latency of b-wave of Max-R was decreased (P<0.05). On 6 weeks after the intervention, the amplitude of b-wave of Rod and the amplitude of a-wave, b-wave of Max-R and the total amplitudes of OPs in group D were increased compared with group B and C (P<0.05), the latency of b-wave of Rod and Max-R in group D were decreased compared with group C (P<0.05). On 10 weeks after molding, each retinal layers were disordered in diabetes mellitus group. On 2 weeks after the intervention, the number of cells in the retinal layers in group B and C were reduced compared with group A, and the structure was more disorder. On 4 weeks after the intervention, the structure of each retina layer in group D arranged less disordered, and the number of retinal ganglion cells was more than group B and C. It was also found that the retinal vascular endothelial expanded and retinal blood vessels cells proliferated. ConclusionThe function of retina in diabetes mellitus rats is improved by intravitreal injection of retinal NSCs differentiated from hUCMSCs.