Structure-grain size-synthesis route of silver nanoparticles: a correlation with the cytotoxic effect.

Although engineered silver (Ag) nanopowders offer great promise in various fields of biomedical, industrial and ecological applications, insufficient data is known about their cytotoxicity. The purpose of the present study was the synthesis and then the determination of cytotoxicity effect of Ag powders using the pyrosol method, at various temperatures of 600°C, 650°C and 700°C, respectively by sol-gel method and heat treatments at 500°C, 600°C, 700°C and 800°C. From the structural, compositional and morphological point of view, Ag samples were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) coupled with selected area electron diffraction (SAED) techniques.

Senescence-induced immunophenotype, gene expression and electrophysiology changes in human amniocytes.

The aim of the study was to evidence replicative senescence-induced changes in human amniocytes via flow cytometry, quantitative reverse-transcription-polymerase chain reaction (qRT-PCR) and automated/manual patch-clamp. Both cryopreserved and senescent amniocytes cultured in BIO-AMF-2 medium featured high percentages of pluripotency cell surface antigens SSEA-1, SSEA-4, TRA1-60, TRA1-81 (assessed by flow cytometry) and expression of pluripotency markers Oct4 (Pou5f1) and Nanog (by qRT-PCR). We demonstrated in senescent vs cryopreserved amniocytes decreases in mesenchymal stem cell surface markers.

Electrophysiology, immunophenotype, and gene expression characterization of senescent and cryopreserved human amniotic fluid stem cells.

We characterized human amniotic fluid stem cells (AFSC) in senescent cultures (6 weeks) versus cryopreserved cells using whole-cell patch-clamp, immunophenotyping, and differential gene expression profiling for senescence genes. We evidenced five ion current components (outward rectifier, A-type, inward rectifier, and big conductance Ca-dependent K currents, fast voltage-dependent Na currents). Senescent AFSC showed reduced expression of CD90, CD44, CD133, over 500-fold increase of interferon gamma and telomerase reverse transcriptase genes, increased cycle-dependent kinase 4 inhibitors, p53-binding protein 1, and decreased calreticulin and CD44.

Bioactive ZnO Coatings Deposited by MAPLE-An Appropriate Strategy to Produce Efficient Anti-Biofilm Surfaces.

Deposition of bioactive coatings composed of zinc oxide, cyclodextrin and cefepime (ZnO/CD/Cfp) was performed by the Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. The obtained nanostructures were characterized by X-ray diffraction, IR microscopy and scanning electron microscopy. The efficient release of cefepime was correlated with an increased anti-biofilm activity of ZnO/CD/Cfp composites.

Development of Scaffolds for Vascular Tissue Engineering: Biomaterial Mediated Neovascularization.

Cardiovascular diseases remain the leading cause of mortality or disabled quality of life for people over the world. The necessity of neovascularization is essential for re-establishing the tissue functions after a major lesion that occurs in patients with cardiovascular disorders, such as ischemia, atherosclerosis, diabetes, peripheral vascular disease and burn wounds. This review focuses on the recent data regarding the polymers and scaffolds that are used for improving neovascularization with emphasis on the biocompatibility and mechanisms involved in stem cells proliferation, migration, adherence, differentiation and organization in vascular networks.

Histone acetylation regulates the expression of HoxD9 transcription factor in endothelial progenitor cells.

The homeobox (Hox) genes encode transcription factors that are involved in the morphogenesis of body. Recent data showed that the HoxD transcription factors control the cardiovascular system development, by modulation of endothelial cell proliferation and differentiation. For our knowledge, the role of histone acetylation in expression of HoxD9 has not been studied to date; therefore, the aim of this study was to investigate the expression of HoxD9 in endothelial progenitor cells after treatment with valproic acid (VPA), a histone deacetylase inhibitor.

Recellularization potential assessment of Wharton's Jelly-derived endothelial progenitor cells using a human fetal vascular tissue model.

Mesenchymal stem cells isolated from Wharton's Jelly have demonstrated an excellent differentiation potential into the endothelial lineage. We hypothesize that endothelial progenitor cells differentiated from Wharton's Jelly-derived mesenchymal stem cells have the potential to repopulate a decellularized vascular bed employed as a biological scaffold. For this purpose, we aimed at investigating the behavior of the endothelial progenitor cells in the decellularized matrix and their potential to repopulate decellularized human vascular tissue.

Anionic polymers and 10 nm Fe₃O₄@UA wound dressings support human foetal stem cells normal development and exhibit great antimicrobial properties.

The aims of this study were the development, characterization and bioevaluation of a novel biocompatible, resorbable and bio-active wound dressing prototype, based on anionic polymers (sodium alginate--AlgNa, carboximethylcellulose--CMC) and magnetic nanoparticles loaded with usnic acid (Fe₃O₄@UA). The antimicrobial activity was tested against Staphylococcus aureus grown in biofilms. The biocompatibility testing model included an endothelial cell line from human umbilical vein and human foetal progenitor cells derived from the amniotic fluid, that express a wide spectrum of surface molecules involved in different vascular functions and inflammatory response, and may be used as skin regenerative support.

Histone deacetylase (HDAC) inhibitors down-regulate endothelial lineage commitment of umbilical cord blood derived endothelial progenitor cells.

To test the involvement of histone deacetylases (HDACs) activity in endothelial lineage progression, we investigated the effects of HDAC inhibitors on endothelial progenitors cells (EPCs) derived from umbilical cord blood (UCB). Adherent EPCs, that expressed the endothelial marker proteins (PCAM-1, CD105, CD133, and VEGFR(2)) revealed by flow cytometry were treated with three HDAC inhibitors: Butyrate (BuA), Trichostatin A (TSA), and Valproic acid (VPA). RT-PCR assay showed that HDAC inhibitors down-regulated the expression of endothelial genes such as VE-cadherin, CD133, CXCR4 and Tie-2.

Integration properties of Wharton's jelly-derived novel mesenchymal stem cells into ventricular slices of murine hearts.

Wharton's jelly (WJ) is a rich source of multiple-lineage differentiating cells, recently proposed for cell replacement therapy. However, their ability to integrate into the cardiac tissue has not been elucidated, yet. We employed in vitro cardiac transplantation models to investigate the capacity of a novel population of human WJ-derived mesenchymal stem cells (nMSCs) to integrate into both living and ischemic cardiac tissue.

Direct contact of umbilical cord blood endothelial progenitors with living cardiac tissue is a requirement for vascular tube-like structures formation.

The umbilical cord blood derived endothelial progenitor cells (EPCs) contribute to vascular regeneration in experimental models of ischaemia. However, their ability to participate in cardiovascular tissue restoration has not been elucidated yet. We employed a novel coculture system to investigate whether human EPCs have the capacity to integrate into living and ischaemic cardiac tissue, and participate to neovascularization.