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Background The multipotent differentiation features of induced pluripotent stem cells (iPSCs) offer a new option for cell replacement therapy of many clinical diseases.In ophthalmology,iPSCs are a good model in studying the pathogenic mechanism of degenerative ocular diseases.A better identification method for iPSCs is critical for analyzing the in vivo biological characteristics of iPSCs.Objective This study was to investigate the feasibility and stability of labeling iPSCs with quantum dots.Methods Human umbilical mesenchymal stromal cells-iPSC lines were cultured and amplified on matrigel,and the characteristics of iPSCs were evaluated by immunofluorescence.Different concentrations (5.0,7.5 and 10.0 nmol/L) of quantum dots with a CdSe/ZnS nuclear shell structure were used to label iPSCs after passaging and proliferation.The labeling outcome was observed with a three-dimensional deconvolution real-time live cells imaging system.The labeled iPSCs were subsequently cultivated,and then changes in fluorescence intensity were examined 7 days after the first and the second passaging of iPSCs.Results iPSCs were observed to grow in a clonal manner under the inverted microscope.The iPSC markers,OCT4 and Nanog,were detected by immunofluorescence.With increasing concentrations of quantum dots,the fluorescence intensities representing the levels of OCT4 and Nanog in iPSCs were gradually elevated,with optimal levels of fluorescence observed at a concentration of 10 nmol/L of quantum dots.The fluorescent labeling of OCT4 and Nanog in iPSCs remained and weakened gradually till day 7 even after the second passage.Conclusions Quantum dots labeling could be used to track iPSCs in a dose-independent manner.The fluorescent signal from the quantum dots labeling the iPSCs lasts 2 weeks at least.
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Background Induced pluripotent stem cells (iPSCs)can differentiate into various types of somatic cells without causing ethical controversy and immune rejection in clinical activity,which is similar to differentiation ability of embryonic stem cells.So,iPSCs may be used as seed cells for tissue engineering corneal endothelial reconstruction.Objective The present study was to survey the morphologic change of iPSCs after coculture with corneal endothelium cells(CECs) under the atomic force microscopy(AFM).Methods Rabbit CECs and human MMC-iPSCs were isolated and cultured respectively.The iPSCs were identified with the marker by immunochemistry.iPSCs passaged for 7 days were then cultured with 60％ confluent CECs to establish the co-culture model.The surface morphology and cellular membrane ultrastructure of differentiated iPSCs after induced by CECs were examined by AFM combination with inverted microscope,and compared with CECs and undifferentiated iPSCs.Results Thelengthand width were(66.93±10.48)μm and (44.85 ± 8.14) μm in CECs,(12.51±1.40)μm and (10.93 ±1.69) μm in uninduced iPSCs,and(36.12±10.29) μm and(31.53±9.65)μm in CECs-induced iPSCs.Both the length and width values of CECs-induced iPSCs were statistically bigger than those uninduced iPSCs,with significant differences between them (P＜0.05),but no significant difference was seen in the width valne of CECs-induced iPSCs in comparison with CECs(P＞0.05).The convex structure of CECs cytomembrane surface showed the digitation in shape with the size and height(2.11 ± 1.03) μm and (115.68±92.08) nm respectively,and the concave structure of cytomembrane surface of CECs was fenestrae-like depression and the size was (1.49 ± 0.65) μm.The numerical valuc of mean square root roughness (Rq)and average roughness (Ra)of cytomembrane surface of CECs were(39.20±7.82)nm and (30.37±5.32)nm respectively.The convex surface of cytomembrane of iPSCs was granular-like in shape with size and height(0.39±0.22)μm and(13.11±9.18)nm respectively.The concave surface of cytomembrane of iPSCs was worm-eaten-like concave with the size(0.34±0.18)μm.The numerical value of Rq and Ra of geometrical parameters of cytomembrane surface of iPSCs were (26.60 ± 4.93)nm and (9.97 ± 3.78) nm respectively.The convex surface of cytomembrane of induced iPSCs was digital-like in shape with the size and height (1.91±0.76) μm and(106.55±77.27) nm respectively.The concave surface of cytomembrane of induced iPSCs was fenestrae-like depression and the size of concave was(1.6l±1.25) μm.The numerical value of Rq and Ra on surface of cytomembrane of induced iPSCs was (57.33± 12.80) nm and (43.63± 11.17) nm respectively.The numerical values of the size and height of convex,the size of concave,Rq and Ra on surface of cytomembrane in induced iPSCs were statistically bigger than in iPSCs(P＜0.05)and were not significant differences in comparison with CECs (P＞0.05).Conclusions Morphology of iPSCs translate toward the CECs after induce for 7 days under the AFM.This outcome lays the foundation for further study on iPSCs.
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The establishment of induced pluripotent stem cells(iPSCs)has been a major breakthrough in the field of stem cell research since 2006,and it made possible for the use of stem cells in treating retinal degenerative diseases.Research showed that fibroblast,B lymphocytes,neural stem cells,hair corneous cells,pancreatic cells,mesenchymal cells of umbilical cord stroma and amniotic membrane can be reprogrammed as iPSCs,and they are capable of differentiating into specific types of cells.Some novel developments in iPSCs study in ophthalmology also were observed over the past few years.Induced iPSCs can differentiate into retinal pigment epithelial cells,photoreceptors and other retinal cells,which lay a foundation for the therapy of retinal degenerative diseases.Differented from traditional treatment of stem cells,the generation of iPSCs makes it possible to utilize somatic cells derived from patients for stem cell therapy without provoking ethical and immunological problems.The generation of iPSCs,the current research about iPSCs in the ophthalmic field,the limitations of iPSCs in the clinic and their future development and application were reviewed.
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· AIM: To investigate the complications of intravitreal triamsinolone acetonide (TA) injection in vitrectomy for proliferative diabetic retinopathy (PDR).· METHODS: From February 2005 to January 2007, 18patients (18 eyes) with PDR who were injected with TA in vitrectomy were observed retrospectively after surgery.· RESULTS: During a postoperative follow-up period of 3 to 6 months (mean 4.6 months), some complications including deposit of TA granules on the macular region and surface of the retina (3 eyes), postoperative vitreous hemorrhage (3eyes), elevated intraocular pressure (2 eyes) and pseudohypopyon (1 eye)were observed.· CONCLUSION: The complications after surgery such as deposit of TA granules on the macular region and surface of the retina and pseudohypopyon could be cured without any special treatment. All eyes with elevated intraocular pressure after surgery were controlled by drug. Re-operation may be an effective method for patients with unabsorbable vitreous hemorrhage after vitrectomy.