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Objective: One of the main approaches to preventing skin ageing is to protect fibroblast cells from oxidative stress. The promoting effect of the human amniotic membrane extract (hAME) on re‐epithelization, proliferation and migration of cells in wound healing has been already well studied. This experimental study aimed to investigate the antioxidant activity of hAME against hydrogen peroxide (H2O2)‐induced dermal fibroblast damage. Methods: Here, to establish the ageing model, human foreskin fibroblasts (HFFs) were exposed to 200 μM H2O2 for 2 h. HFFs were treated with 0.1 mg/ml AME for 24 or 48 h before or/and after H2O2 exposure. A total of 48 h following the H2O2 treatment, we measured cell proliferation, viability, senescence‐associated β‐galactosidase (SA‐β‐Gal), antioxidants and preinflammatory cytokine (IL‐6) levels, as well as the expression of senescence‐associated genes (P53 and P21). Results: The obtained results indicated that under oxidative stress, AME significantly increased cellular viability and not only promoted the cell proliferation rate but also attenuated apoptotic induction condition (p < 0.001). AME also significantly reversed the SA‐β‐Gal levels induced by H2O2 (p < 0.001). Additionally, both pre‐ and post‐treatment regimen by AME down‐regulated the expression of senescence marker genes (p < 0.001). Moreover, AME declined different oxidative stress biomarkers such as superoxide dismutase and catalase and increased the glutathione amount. Conclusion: Altogether, our results indicated that AME had a remarkable antioxidant and antiageing activity as pre‐ and post‐treatment regimen, pointing to this compound as a potential natural‐based cosmeceutical agent to prevent and treat skin ageing conditions. [ABSTRACT FROM AUTHOR]

Objective: Ex vivo expansion is a promising strategy to overcome the low number of human umbilical cord blood hematopoietic stem cells (hUCB-HSCs). Although based on the obtained results in unnatural physiological condition of irradiated genetically immune-deficient mouse models, there has always been concern that the expanded cells have less engraftment potential. The purpose of this study was to investigate effect of common ex vivo expansion method on engraftment potential of hUCB-mononuclear cells (MNCs), using normal fetal mouse, as a model with more similarity to human physiological conditions. Materials and Methods: In this experimental study, briefly, isolated hUCB-MNCs were cultured in common expansion medium containing stem cell factor, Flt3 ligand and thrombopoietin. The unexpanded and expanded cells were transplanted to the fetal mice on gestational days of 11.5-13.5. After administration of human hematopoiesis growth factors (hHGFs), presence of human CD45+ cells, in the peripheral blood of recipients, was assessed at various time points after transplantation. Results: The expanded MNCs showed 32-fold increase in the expression of CD34+38- phenotype and about 3-fold higher clonogenic potential as compared to the uncultured cells. Four weeks after transplantation, 73% (19/26) of expanded-cell recipients and 35% (7/20) of unexpanded-cell recipients were found to be successfully engrafted with human CD45+ cells. The engraftment level of expanded MNCs was significantly (1.8-fold) higher than unexpanded cells. After hHGFs administration, the level was increased to 3.2, 3.8 and 2.6-fold at respectively 8, 12, and 16 weeks of post transplantation. The increased expression of CXCR4 protein in expanded MNCs is a likely explanation for the present findings. Conclusion: The presented data showed that expanded MNCs compared to unexpended cells are capable of more rapid and higher short-term engraftment in normal fetal mouse. It could also be suggested that in utero transplantation (IUT) of normal fetal mice could be an appropriate substitute for NOD/SCID mice in xenotransplantation studies. [ABSTRACT FROM AUTHOR]

Abstract: The MEK/ERK pathway is found to be important in regulating different biological processes such as proliferation, differentiation and survival in a wide variety of cells. However, its role in self‐renewal of haematopoietic stem cells is controversial and remains to be clarified. The aim of this study was to understand the role of MEK/ERK pathway in ex vivo expansion of mononuclear cells (MNCs) and purified CD34+ cells, both derived from human umbilical cord blood (hUCB). Based on our results, culturing the cells in the presence of an inhibitor of MEK/ERK pathway—PD0325901 (PD)—significantly reduces the expansion of CD34+ and CD34+ CD38− cells, while there is no change in the expression of stemness‐related genes (HOXB4, BMI1). Moreover, in vivo analysis demonstrates that PD reduces engraftment capacity of ex vivo expanded CD34+ cells. Notably, when ERK pathway is blocked in UCB‐MNCs, spontaneous erythroid differentiation is promoted, found in concomitant with increasing number of burst‐forming unit‐erythroid colony (BFU‐E) as well as enhancement of erythroid glycophorin‐A marker. These results are in total conformity with up‐regulation of some erythroid enhancer genes (TAL1, GATA2, LMO2) and down‐regulation of some erythroid repressor genes (JUN, PU1) as well. Taken together, our results support the idea that MEK/ERK pathway has a critical role in achieving the correct balance between self‐renewal and differentiation of UCB cells. Also, we suggest that inhibition of ERK signalling could likely be a new key for erythroid induction of UCB‐haematopoietic progenitor cells. [ABSTRACT FROM AUTHOR]