Search results for "Stem Cell"
showing 10 items of 2354 documents
Role of p16INK4a and BMI-1 in oxidative stress-induced premature senescence in human dental pulp stem cells
2017
Human dental pulp stem cells (hDPSCs) are a source for cell therapy. Before implantation, an in vitro expansion step is necessary, with the inconvenience that hDPSCs undergo senescence following a certain number of passages, loosing their stemness properties. Long-term in vitro culture of hDPSCs at 21% (ambient oxygen tension) compared with 3–6% oxygen tension (physiological oxygen tension) caused an oxidative stress-related premature senescence, as evidenced by increased β-galactosidase activity and increased lysil oxidase expression, which is mediated by p16INK4a pathway. Furthermore, hDPSCs cultured at 21% oxygen tension underwent a downregulation of OCT4, SOX2, KLF4 and c-MYC factors, w…
Direct pericyte-to-neuron reprogramming via unfolding of a neural stem cell-like program
2018
Ectopic expression of defined transcription factors can force direct cell-fate conversion from one lineage to another in the absence of cell division. Several transcription factor cocktails have enabled successful reprogramming of various somatic cell types into induced neurons (iNs) of distinct neurotransmitter phenotype. However, the nature of the intermediate states that drive the reprogramming trajectory toward distinct iN types is largely unknown. Here we show that successful direct reprogramming of adult human brain pericytes into functional iNs by Ascl1 and Sox2 encompasses transient activation of a neural stem cell-like gene expression program that precedes bifurcation into distinct…
Erratum to: Donor age and long-term culture do not negatively influence the stem potential of limbal fibroblast-like stem cells
2016
In regenerative medicine the maintenance of stem cell properties is of crucial importance. Ageing is considered a cause of reduced stemness capability. The limbus is a stem niche of easy access and harbors two stem cell populations: epithelial stem cells and fibroblast-like stem cells. Our aim was to investigate whether donor age and/or long-term culture have any influence on stem cell marker expression and the profiles in the fibroblast-like stem cell population.Fibroblast-like stem cells were isolated and digested from 25 limbus samples of normal human corneo-scleral rings and long-term cultures were obtained. SSEA4 expression and sphere-forming capability were evaluated; cytofluorimetric…
Kinetics of torque teno virus DNA load in saliva and plasma following allogeneic hematopoietic stem cell transplantation
2018
Plasma torque teno virus (TTV) DNA load directly correlates with the degree of T-cell immune reconstitution early after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Here, the kinetics of oral TTV DNA shedding was examined to assess whether quantitation of TTV DNA load in saliva may either replace or complement that in plasma for predicting lymphocyte (ALC) reconstitution after engraftment. This prospective observational study enrolled 38 nonconsecutive allo-HSCT recipients. Saliva and plasma specimens were collected at baseline (pretransplant) and at around days +30, +50, and +90 after allo-HSCT. TTV DNA was quantitated in both specimen types by real-time PCR. ALCs were m…
A risk-adapted approach to treating respiratory syncytial virus and human parainfluenza virus in allogeneic stem cell transplantation recipients with…
2017
Here we report the applicability of a protocol based on clinical conditions and risk factors (RFs) for managing 35 allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients who developed a total of 52 episodes of respiratory viral infections (RVIs) caused by respiratory syncytial virus (RSV; n=19), human parainfluenza virus (HPIV; n=29), or both (n=4) over a 2-year study period. Risk categories were classified as high risk (cat-1) when the immunodeficiency scoring index was >= 3 and/or >= 3 RFs and/or >= 1 co-infective virus(es) were present; the remaining cases were classified as low risk (cat-0). The presence of two or more signs or symptoms including fever (T>38 degrees C…
Dynamics of cytomegalovirus (CMV) plasma DNAemia in initial and recurrent episodes of active CMV infection in the allogeneic stem cell transplantatio…
2011
Preemptive antiviral therapy strategies for active cytomegalovirus (CMV) infection occurring in allogeneic stem cell transplant recipients should be optimized to avoid overtreatment. The current study was aimed at determining whether the analysis of the kinetics of CMV DNA load in plasma may provide useful information for the therapeutic management of active CMV infection in this setting. A total of 59 consecutive patients were included in the study, of which 40 (67.8%) developed 1 (n = 21) or more (n = 19) episodes of CMV DNAemia. The need for antiviral therapy for initial or secondary episodes of CMV DNAemia could not be predicted on the basis of the CMV DNA load value in the first plasma…
Functional patterns of cytomegalovirus (CMV) pp65 and immediate early-1-specific CD8+T cells that are associated with protection from and control of …
2015
Background The functional profile of cytomegalovirus (CMV)-specific CD8+ T cells that associate with protection from and control of CMV DNAemia in allogeneic stem cell transplant (allo-SCT) recipients remains incompletely characterized. Methods We enumerated pp65 and immediate early (IE)-1-specific CD8+ T cells expressing interferon-gamma, tumor necrosis factor-alpha, and CD107a, by flow cytometry in 94 patients at days +30 and +60 after allo-SCT. Results Fifty of 94 patients had CMV DNAemia within the first 100 days after transplant. CMV-specific CD8+ T-cell responses (of any functional type) were more likely to be detected in patients who did not display CMV DNAemia than in those who did …
When should preemptive antiviral therapy for active CMV infection be withdrawn from allogeneic stem cell transplant recipients?
2017
When should preemptive antiviral therapy for active CMV infection be withdrawn from allogeneic stem cell transplant recipients?
An Assessment of the Effect of Human Herpesvirus-6 Replication on Active Cytomegalovirus Infection after Allogeneic Stem Cell Transplantation
2010
Human herpesvirus-6 (HHV-6) may enhance cytomegalovirus (CMV) replication in allogeneic stem cell transplant (allo-SCT) recipients either through direct or indirect mechanisms. Definitive evidence supporting this hypothesis are lacking. We investigated the effect of HHV-6 replication on active CMV infection in 68 allo-SCT recipients. Analysis of plasma HHV-6 and CMV DNAemia was performed by real-time PCR. Enumeration of pp65 and IE-1 CMV-specific IFNgamma CD8(+) and CD4(+)T cells was performed by intracellular cytokine staining. HHV-6 DNAemia occurred in 39.8% of patients, and was significantly associated with subsequent CMV DNAemia in univariate (P=.01), but not in multivariate analysis (P…
Pre-emptive antiviral therapy for active CMV infection in adult allo-SCT patients guided by plasma CMV DNAemia quantitation using a real-time PCR ass…
2013
Pre-emptive antiviral therapy for active CMV infection in adult allo-SCT patients guided by plasma CMV DNAemia quantitation using a real-time PCR assay: clinical experience at a single center