ABSTRACT
Objective To evaluate the feasibility of repair of full-thickness skin defects in nude mice with tissue-engineered skin which was constructed by culture of human amniotic epithelial cells (hAECs) and fibroblasts on human de-epidermized dermis (DED).Methods Healthy human amniotic tissues were treated with trypsin at a low concentration in multi-steps to prepare hAECs,and a two-step collagenase digestion was used to treat healthy children's prepuce tissues to prepare fibroblast suspensions.When fibroblasts were cultured in vitro up to passage 3-5 and hAECs up to passage 2,they were seeded on the reticular dermal surface and basement membrane surface of the DED respectively to construct the tissueengineered skin.A total of 20 heahhy male nude mice aged 3-4 weeks were enrolled into this experiment,and full-thickness skin defects were made on the middle of the back of mice.Then,these mice were randomly divided into 2 groups by using a lottery method,and reconstructed full-thickness tissueengineered skin grafts and vaseline oil gauze were used to cover the wounds in the tissue-engineered skin group and control group respectively.The whole body and transplantation sites of the nude mice were observed on day 7,14,21 and 28 after transplantation,the wound healing time and rate were compared between the above two groups,and skin tissues at the transplantation site were harvested at 4 weeks after transplantation and subjected to histological examination.Results HAECs had stem-cell characteristics and expressed octamer-binding protein-4 (OCT-4) and embryonic marker stage-specific embryonic antigen4 (SSEA-4).After 2-week organ culture,the in vitro reconstructed tissue-engineered skin showed 4-9 continuous layers of stratified epithelium,and the histological structure of the epidermis was similar to that of the normal human skin.Compared with the control group,the tissue-engineered skin group showed significantly higher wound healing rates on day 7,14 and 21 after transplantation (57.49％ ± 6.11％ vs.22.93％ ± 4.26％,92.80％ ± 3.10％ vs.54.57％ ± 7.94％,98.83％ ± 0.25％ vs.91.16％ ± 4.79％,respectively;n =10,t =27.36,32.23,11.80,respectively,all P ＜ 0.001),shorter wound healing time [(21.51 ± 1.51) d vs.(28.80 ± 1.14) d,n =10,t =42.23,P ＜ 0.001],with the color of skin grafts closer to that of autologous skin on day 28 after transplantation.Histological examination revealed distinct stratification of the epithelium,obvious keratinization and favorable growth of cells in the dermis in the tissue-engineered skin group,but thin epithelium with some defects,indistinct stratification of the dermis,and inflammatory cell infiltration in the control group.Condusion Tissue-engineered skin constructed by the culture of hAECs and fibroblasts on human DED can survive in nude mice after transplantation,resulting in a more favorable healing of wounds,and is expected to serve as a kind of ideal tissue-engineered skin.
ABSTRACT
[ ABSTRACT] AIM:To observe the treatment effect and its immune regulation of human amnion epithelial cells ( hAECs) on Alzheimer’ s disease ( AD)-like pathology rat model.METHODS: The hAECs were isolated from amnion with trypsin digestion, and the phenotype of hAECs was analyzed by flow cytometry.SD rats ( n=48) were randomly divid-ed into sham control group, model group, medium group and hAECs group.AD-like pathology rat model was induced by bilateral intraventricular injection of lipopolysaccharide (LPS).hAECs (5 ×105) were injected into the hippocampus of the AD-like pathology rats.At 2 weeks after transplantation, the animals were tested by Morris water maze to observe the function of learning and memory.The pathological change of the brain was observed by HE staining.The expression of am-yloid β-protein 42 (Aβ42) and Tau protein and the level of acetylcholine (ACh) in the injury brain were determined by immunohistochemistry.The survival and differentiation of hAECs in the hippocampus were measured by immunofluorescent technique.The percentages of lymphocyte subsets in the peripheral blood mononuclear cells were analyzed by flow cytome-try.The contents of serum cytokines were detected by cytometric bead array.RESULTS:Compared with model group and medium group, hAECs group showed shortened escape latency ( P<0.01) , increased frequency of going through the plat-form (P<0.05), reduced loss of hippocampal neurons, decreased expression of Tau protein and Aβ42 in the hippocampus (P<0.05), increased ACh level in the hippocampus (P<0.05), decreased percentages of Th1 and Th17 subsets, in-creased percentages of Th2 and Treg cells ( P<0.05) , decreased concentrations of IFN-γand IL-2 in the serum, and in-creased concentration of IL-4 ( P<0.05 ) .CONCLUSION: hAECs improve the cognitive learning and memory function and alleviate pathologic damage of hippocampus through immune regulation in AD-like pathology rats.
ABSTRACT
Background Studies demonstrated that human amniotic epithelial cells (AECs) have some characteristics of embryonic stem cells and they were used to re-establish the surface of eyes. Human AECs may serve as new seed cells in tissue engineering for corneal epithelium reconstitution in the future. Objective The present study was to investigate the application value of human amniotic epithelium cells transfected by lentiviral vectormediated enhanced green fluorescent protein (EGFP) gene as new seed cell source for engineering the corneal surfacelayer. Methods Lentiviral vector carrying the objective gene EGFP was transfected into human amniotic epithelial cells (pLenti6/V5-DEST),and the transient expression of the transgene in the human amniotic epithelial cells was observed under the fluorescence microscope. Flow cytometry was used to detect the positive expression rates of EGFP in transfected cells. The transfected human amniotic epithelial cells were seeded onto the fresh corneal stromal surface of New Zealand white rabbit and cultured in vitro. The stem cell deficiency ( SCD ) models were established by cutting off the limbus of cornea in 20 eyes of New Zealand white rabbits, and the model rabbits were then divided into 2 groups randomly. The transplanted grafts carrying the pLenti6/V5-DEST-EGFP gene-transferred human amniotic epithelium cells were regarded as the pLenti6/V5-DEST-EGFP group, and the corneal stroma graft without any epithelial cell served as the control group. The opacity of stroma and corneal conjunctivalization and vascularization were observed daily. The rabbits' eyes were extracted one month after operation. The expression of EGFP in the cornea was detected under the fluorescence microscope, and the expression of CK8, CK18 and CK12 in cornea was detected by immunohistochemical staining. Results The shape of the transferred human amniotic epithelial cells resembled normal human amniotic epithelial cells. 48 hours after the transient transfection of EGFP presented with the highest expression level throughout the observation duration, with a positive expression rate of EGFP of 61.5% ,showing significant differences in comparison with that of 12 ( 5.24% ) , 24 ( 38.27% ) or 96 ( 39. 10% ) hours ( P ＜0. 05) post-transfection; but no obvious difference was found in the positive rate of transiently transfected EGFP between 48 hours and 72 hours ( 58.36% ) ( P＞0. 05 ). Six cornea grafts were clear in 1 month and two corneas were rejected during the observation period in the pLenti6/V5-DEST-EGFP group. A few new blood vessels were seen around the graft. Ten corneas of the control group became opaque and cloudy with new blood vessels growth around the grafts. Imunohistochemistry revealed the positive expressions of CK8, CK1 8 and CK12 in the corneal epithelial layer in the pLenti6/V5-DEST-EGFP group. However,the expression of CK12 was absent in the control group. Conclusion Human amniotic epithelium cells transfected with the pLenti6/V5-DEST-EGFP gene is a new and ideal feed cell type to reconstruct the corneal surface layer. Lentivirus is a relatively safe gene transfection vector.