The classical Hippo pathway leads to the phosphorylation of downstream effector molecules Hippo-Yes-associated protein (Yap) and transcriptional coactivator PDZ-binding motif (Taz) serine sites through a kinase response, thereby promoting cell proliferation, controlling cell polarity, changing cytoskeleton, it plays an important regulatory role in various pathophysiological processes such as epithelial-mesenchymal transition and inhibition of cell contact. Studies have shown that Yap/Taz can affect the progression of vitreoretinal diseases, opening up new prospects for the pathogenesis and clinical treatment of diabetic retinopathy, proliferative vitreoretinopathy, and retinal ischemia-reperfusion injury. Exploring the molecular mechanism of Yap/Taz provides a possible therapeutic target for future research in the treatment of retinal fibrosis diseases such as diabetic retinopathy and proliferative vitreoretinopathy. At the same time, regulating the activity of local Yap/Taz in the retina will also become an effective therapeutic target for damage-repair in retinal ischemia-reperfusion injury. However, Yap inhibitors have potential retinal toxicity and are still in the preclinical development stage. Further research on the mechanism of action and clinical safety of Yap inhibitors will provide new methods for the treatment of retinal diseases.
Microvesicles (MVs) is small membrane vesicles released from different cell types under different conditions. Studies have shown that MVs may mediate vascular inflammation, angiogenesis, and other pathological processes. MVs may play an important role in the pathogenesis of diabetic retinopathy (DR) by mediating endothelial cell injury, thrombosis and neovascularization. The plasma MV level may be an effective parameter to monitor the development of DR. This article will summarize the research progress of the relationship between MVs and DR in recent years.
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.
Objective To evaluate the efficacy of perioperative management for vitrectomy of patients with severe systemic disease. Methods The clinical data of 21 patients (22 eyes) with severe systemic disease who underwent vitrectomy were retrospectively analyzed. There were 11 patients (12 eyes) with proliferative diabetic retinopathy, 9 patients (9 eyes) with rhegmatogenous retinal detachment, and 1 patient (1 eye) with intraocular lens dislocation. The preoperative visual acuity ranged from hand movement to 0.6. There were 4 patients (5 eyes) with renal insufficiency undergoing renal dialysis, 7 patients (7 eyes) with myocardial infarction or coronary artery stenosis received cardiac bypass surgery or coronary stent implantation, 2 patients (2 eyes) with severe arrhythmia received cardiac pacemaker implantation or radiofrequency catheter ablation, 5 patients (5 eyes) with cerebral infarction, 2 patients (2 eyes) with hemophilia, and 1 patient (1 eye) with aplastic anemia. For patients with cardiac bypass surgery or coronary stent implantation, anticoagulants were switch to low molecular heparin at 7 days before vitrectomy. For patients undergoing renal dialysis, 0.4 ml low molecular heparin was used during renal dialysis at one day before vitrectomy, protamine and heparin were administered after vitrectomy. Prothrombin complex was infused from 1 day before surgery to 5 days after surgery for Hemophilia B patients.6 patients (6 eyes) underwent phacoemulsification, and 1 patient (1 eye) underwent ciliary sulcus fixed intraocular lens implantation. 14 patients (14 eyes) underwent silicone oil tamponade,5 patients (6 eyes) underwent C3F8 tamponade.Results The postoperative visual acuity ranged from light perception to 1.0. The vision increased in 18 patients (19 eyes), unchanged in 2 patients (2 eyes), and decreased in 1 patient (1 eye). The retina attached in all eyes postoperatively. The postoperative complications mainly included mild anterior chamber bleeding in 4 patients (4 eyes), severe anterior chamber bleeding in 1 patient (1 eye), mild retinal hemorrhage in 2 patients (2 eyes), optic disc bleeding in 2 patients (3 eyes), temporary elevation of intraocular pressure in 1 patient (1 eye), and neovascular glaucoma in 1 patient (1 eye). Serum creatinine increased in 1 patient and hypertension in 1 patient within 1 week postoperatively. Conclusions Severe systemic disease is not an absolute contraindication for vitrectomy. Vitrectomy can be successfully performed with better outcomes under the proper perioperative management of systemic disease.
Objective To observe the effects of simvastatin on endothelial progenitor cells (EPCs) from peripheral blood and retinopathy in rats with diabetic retinopathy (DR). Methods Eighty male Wistar rats were divided into normal control group (group A), DR model group (group B), DR with placebo group (group C), DR with simvastatin group (group D), with twenty rats in each group. The rats in group C and D received streptozotocin (STZ) injection to induce diabetic retinopathy. The rats in the group A and B were not intervened. The rats were gavaged with 20 mg/kg simvastatin (group D) or same volume of distilled water (group C) once a day. Flow cytometry was used to identify and count the number of EPCs from peripheral blood at the 1st，4th and 12th week after injection. Evans blue perfusion was used to detect the bloodretinal barrier (BRB) permeability. Immunohistochemical staining was used to observe the expression of CD31 in the retina. Real-time reverse transcriptionpolymerase chain reaction (RT-PCR) was used to measure the mRNA expression of eNOS, iNOS and Ang-1. The correlation between changes of EPCs and DR morphological changes was analyzed. Results At the 1st，4th and 12th week after injection, compared with the group A, the number of EPCs was decreased in group C; Compared with the group B and C, the number of EPCs was increased in group D (t=4.967, 5.648, 6.688, 6.042, 7.392, 7.454;P＜0.05); there was no statistical difference of EPCs number between group B and C (t=0.525, -0.249, -0.619; P＞0.05), group A and D (t=6.733, 2.794, -5.535; P＜0.05) respectively. The structure of retina was continuous and its capillary structure was normal in control group. The retinal layers were edema and the retina developed telangiectatic vessels and many ganglion cells developed vacuolar degeneration in group B and C. The layers tissue of retina was less edema and gradually arranged in group D. The BRB permeability was significantly increased in group B and D compared with group A. The BRB permeability was significantly decreased in group D compared with group B (F=65.808，P＜0.05). The CD31 expression in group D was obviously higher than that in group A, B and C (F=24.799，P＜0.05). The eNOS expression in group B was obviously lower than that in group A, while in group D was obviously higher than that in group B (t=-2.750，2.230；P＜0.05). The iNOS and Ang-1 expression in group B were obviously higher than those in group A, while in group D was obviously lower than that in group B (t=3.881，-1.144，4.244，-1.458；P＜0.05). There was no difference in BRB permeability, eNOS, iNOS and Ang-1 expression between group B and C (t=0.480,-0.877, 0.062, 0.220; P＞0.05). Conclusions Simvastatin could mobilize DR rats peripheral blood EPCs, induce migration and differentiation of retinal endothelial cell, slow down the DR progress by regulating the expression of endothelium factors such as eNOS and iNOS.
Objective To investigate the amounts of endothelial progenitor cells (EPCs) in peripheral blood of patients with proliferative diabetic retinopathy (PDR). Methods Forty patients with PDR (PDR group), thirty patients with type 2 diabetes mellitus (DM) without DR (DM group), and twenty age-matched normal subjects (control group) were enrolled in this study. Blood samples were treated by repeated centrifugation and stained with monoclonal antibodies. At least 2times;105 cells were analyzed by flow cytometry. EPCs were identified by CD34 and CD133 antibody. The correlation between EPCs numbers and DR duration, glycosylated hemoglobin, serum lipids was analyzed. Results The number of EPCs in PDR, DM and control group were (49plusmn;12)、(35plusmn;11)、(90plusmn;25) cells/ml respectively, the difference was statistically significant (F=56.260, P=0.000). There was a positive correlation between EPCs numbers and DR duration (r=0.564, P＜0.05). However there was no correlation between EPCs numbers and glycosylated hemoglobin (r=-0.170, P＞0.05) or triglyceride levels (r=0.261, Pgt;0.05). Conclusions The number of EPCs in peripheral blood of PDR patients was decreased. EPCs might play an important role in the pathogenesis of PDR.
ObjectiveTo investigate whether exosomes derived from atorvastatin (ATV)-pretreated human umbilical cord mesenchymal stem cells (ATV-MSC-EXO) alleviate high glucose-induced injury in human retinal vascular endothelial cells (HREC) via the protein kinase B (AKT)/endothelial nitric oxide synthase (eNOS) signaling pathway. MethodsThe optimal pretreatment concentration of ATV was determined using the cell counting Kit-8 (CCK-8) assay. Exosomes derived from mesenchymal stem cells (MSC-EXO) and ATV-pretreated MSC (ATV-MSC-EXO) were isolated and extracted, and their morphology and surface markers were characterized by transmission electron microscopy, nanoparticle tracking analysis, and Western blotting (WB). The uptake capacity of exosomes by human retinal vascular endothelial cells (HREC) was evaluated using a fluorescence labeling assay. In vitro cultured HREC were divided into the following groups: normal control group (NC group), high glucose group (HG group), high glucose+MSC-EXO group (MSC-EXO group), high glucose+ATV-MSC-EXO group (ATV-MSC-EXO group), high glucose+ATV-MSC-EXO+AKT inhibitor group (ATV-MSC-EXO-MK-2206-2HCL group), and high glucose+ATV-MSC-EXO+eNOS inhibitor group (ATV-MSC-EXO-L-NAME group). Cell proliferation and apoptosis were detected using CCK-8 and flow cytometry, respectively. The protein expression levels of B-cell lymphoma/leukemia-2 (Bcl-2), Bcl-2-associated protein (Bax), and Caspase-3 were measured by WB. In addition, the regulatory effects of ATV-MSC-EXO on the AKT/eNOS signaling pathway and its downstream functional molecules were analyzed by detecting the phosphorylation levels of AKT (P-AKT/AKT) and eNOS (P-eNOS/eNOS) via WB, the mRNA expression levels of AKT and eNOS by quantitative real-time polymerase chain reaction, and the concentrations of nitric oxide (NO) and endothelin-1 (ET-1) using commercial NO and ET-1 assay kits. ResultsThe optimal pretreatment concentration of ATV was 1 μmol/L. ATV-MSC-EXO exhibited similar morphology and particle size to MSC-EXO and were efficiently taken up by HREC. Under high glucose conditions, ATV-MSC-EXO significantly enhanced the viability of HREC (F=83.24, P＜0.000 1) and inhibited apoptosis (F=77.39, P＜0.000 1). WB analysis further confirmed that ATV-MSC-EXO upregulated the expression of the anti-apoptotic protein Bcl-2 (F=53.17), while downregulating the pro-apoptotic proteins Bax (F=36.49) and Caspase-3 (F=60.75) (P＜0.001). In addition, ATV-MSC-EXO markedly increased the protein levels of P-AKT/AKT (F=107.60) and P-eNOS/eNOS (F=38.59), as well as the relative mRNA expression of AKT, eNOS (F=203.60, 315.00; P＜0.000 1). Furthermore, ATV-MSC-EXO promoted NO production (F=407.40) and suppressed the relative expression of ET-1 (F=49.76) (P＜0.000 1). ConclusionATV-MSC-EXO enhances the viability and inhibits apoptosis of HREC under high glucose conditions by activating the AKT/eNOS signaling pathway.
ObjectiveTo investigate the effects of migration and expression from chemokine receptor 4 (chemokine receptor-4, CXCR4) of rat bone marrow mesenchymal stem cells (BMSCs) which were pretreated by atorvastatin (ATV) in vitro.MethodsIsolated, cultivated, identified the BMSCs, pretreated P4-P6 of BMSCs with different concentrations of ATV for 12 hours. The experimental group was divided into control group, 0.1 nM/L (group 0.1 nM), 1 nM/L (1 nM group), 10 nM/L (10 nM group), 100 nM/L (100 nM group), 1 000 nM/L (1 000 nM group). The mRNA and protein of CXCR4 were determined by real time-polymerase chain reaction and Western blot. Immunofluoreseence assay were used to detect the expression levels of CXCR4. The migration ability of BMSCs were measured by transwell chamber.ResultsImmunofluoreseence assay showed the protein level of CXCR4 of group 1 nM and 10 nM were significantly higher than the other group. RT-PCR and Western blot showed the protein and mRNA level of CXCR4 in 10 nM was higher than that in group 1 nM. The migration ability of group 10 nM was higher than 1 nM and control group.ConclusionsATV can be dose-dependent promote expression levels of CXCR4 of BMSCs cultivated in vitro.