Recent advances in the biology of fetal/cord blood stem cells

Recent developments of transplantation for the cure of paediatric leukaemias and solid tumours have led to increased interest in cord blood (CB) as an advantageous source of haematopoietic stem cells (HSC). Cord blood stem cells have unique biological properties: primitivity, a high proliferative capacity, a high level of telomerase, with a wide differentiation potential towards all haematopoietic lineages. Very recently, the wide differentiative potential of embryonic stem cells (ESC) towards a variety of tissues has led to a renewed interest into the possibility of producing tissues in vitro which are useful for replacing affected tissues and organs for the treatment of many conditions (cardiac infarction, hepatic failure, diabetes, osteoporosis). However, the use of human ES (raises ethical concern because their isolation requires the disruption of the blastocyst. Unsuspected properties of tissue stem cells to transdifferentiate towards a wide variety of different tissues have led to renewed interest in very primitive neonatal/fetal blood, which is a source of stem cells that may be more capable of producing high numbers of specialised cells for cell replacement therapies. In this paper, we review recent advances in the manipulation, banking, characterisation, differentiative potential and clinical use of neonatal/fetal stem cells

Cell processing for haplo-identical hematopoietic stem cell transplantation: Automated washing and immunomagnetic-positive selection

BACKGROUND AIMS: Immunomagnetic cell selection (ICS) of CD34(+) cells is being used increasingly in allogeneic transplantation in order to reduce T-cell quantity. The aim of this study was to evaluate an automated washing protocol before immunomagnetic selection. METHODS: The automated method was compared with a conventional washing procedure. In the study group the cell processing using the automated procedure, both before and after antibody incubation, was performed with a Sepax S-100 device. The efficacy of the automated procedure was compared with the control group, where washing were performed using a standard method. RESULTS: The results obtained after pre-incubation washing performed using the automated system showed a total nucleated cell (NC) and CD34(+) cell recovery of 84.87% (71.80-105, SD 8.62; range, standard deviation) and 83.45% (47-109, SD 16.12), respectively. The NC and CD34(+) cell recovery after the pre-incubation washing cycle was performed using the standard method was 75.54% (38.36-97.76, SD 22.5) and 61.51% (30.87-81.79, SD 19.3), respectively. The CD34(+) cell recovery after ICS was 51.27% (13.77-98.82, SD 24.97) and 48.89% (15.57-88.24, SD 25.91) for group 1 and group 2, respectively. The average purity in group 1 was 86.46% (67.4-96.10, SD 13.07) and in group 2 84.97% (58.1-97.8, SD 15.58). CONCLUSIONS: The efficacy of the ICS led to an optimal purity without affecting cell recovery, which was higher in group 1. Overall, our data suggest that the automated method is suitable for washing hematopoietic progenitor cell apheresis (HPC-A) concentrates before immunomagnetic cell selection in daily clinical routines

Acute and long-term effects of low-density lipoprotein (LDL)-apheresis on oxidative damage to LDL and reducing capacity of erythrocytes in patients with severe familial hypercholesterolaemia

Several studies have suggested that the oxidative modification of low-density lipoprotein (LDL) could play a key role in the early stages of atherosclerosis. The susceptibility of LDL to oxidation has been found to be greater in patients with coronary heart disease. Familial hypercholesterolaemia (FH) is a powerful clinical model in which to study the predictive role of LDL in atherogenesis. LDL-apheresis is a treatment that is able to decrease lipid levels in plasma. This study was aimed at investigating the reducing capacity of erythrocytes and the in vitro susceptibility to oxidation of LDL isolated from patients with homozygous, heterozygous and double-heterozygous FH, who were created fortnightly with LDL-apheresis or left untreated. In 14 FH patients, at baseline and after a cycle of treatment, the susceptibility of LDL to oxidative modification was analysed by studying the kinetics of conjugate diene formation. Plasma hydroperoxides, polyunsaturated fatty acid content, LDL electrophoretic mobility on agarose, the titre of auto-antibodies against oxidized LDL and serum paraoxonase activity were also measured. Furthermore, in order to evaluate a potential relationship between LDL oxidation and redox status, erythrocyte GSH and ATP levels were determined in FH patients treated regularly or never treated previously by LDL-apheresis. Unlike in the control group, the oxidative status of LDF in all FH patients was modified by LDL-apheresis, as revealed by the higher negative charge and the increase in levels of hydroperoxides and antibodies against oxidized LDL in the plasma. Our findings suggest both an acute effect and a long-term effect of LDL-apheresis in FH patients treated with dextran sulphate cellulose apheresis. The acute effect of LDL-apheresis on the susceptibility to oxidation of plasma and LDL was demonstrated by significant decreases in plasma hydroperoxide content, total LDL concentration and polyunsaturated fatty acid content. The increased resistance of LDL to oxidation was shown by prolongation of the lag time (P 0.001) in the treated group, suggesting the activation of reducing mechanisms

Tuning the photoelectrochemical properties of hierarchical TiO2 nanostructures by control of pulsed laser deposition and annealing in reducing conditions

Nanostructured TiO2 films with hierarchical morphology were synthesized by Pulsed Laser Deposition (PLD) and tested as photoanodes for photoelectrochemical water splitting. The tuning of their photoresponse was addressed by employing oxygen-poor conditions both during the growth and the post-deposition annealing of the material: depositions were performed in different Ar/O2 background gas mixtures from both TiO2 and Ti targets, while thermal treatments, after standard air annealing for crystallization, were performed in a Ar/H2 mixture. By testing the double-annealed photoanodes in a three-electrode cell with solar simulator illumination, clear trends with optimal synthesis conditions for each target material appeared; for these conditions, also the effect of vacuum annealing was studied. The morphological, structural and optical properties were investigated by SEM, Raman spectroscopy and UV-visible-IR spectroscopy. From these observations, it emerged that the films deposited in the presence of oxygen do not show substantial differences in their morphology/structure, on the contrary of pure Ar-deposited films; thus, the trends in photoresponse can be related to differences in the defect concentration of the material, induced by depositions in the different Ar/O2 atmospheres and by annealing in Ar/H2 mixture or vacuum. In particular, the reported results suggest that some degree of oxygen shortage in the deposition process leads to a better photoelectrochemical performance, and a combination between improved charge transport and surface hydrogenation/reduction effect, leading to enhanced photoresponse, is suggested. This work elucidates the possibility of an accurate tuning of the material photoactivity by control of the deposition and annealing conditions

Tuning the photoelectrochemical properties of hierarchical TiO2 nanostructures by control of pulsed laser deposition and annealing in reducing conditions

Nanostructured TiO2 films with hierarchical morphology were synthesized by Pulsed Laser Deposition (PLD) and tested as photoanodes for photoelectrochemical water splitting. The tuning of their photoresponse was addressed by employing oxygen-poor conditions both during the growth and the post-deposition annealing of the material: depositions were performed in different Ar/O2 background gas mixtures from both TiO2 and Ti targets, while thermal treatments, after standard air annealing for crystallization, were performed in a Ar/H2 mixture. By testing the double-annealed photoanodes in a three-electrode cell with solar simulator illumination, clear trends with optimal synthesis conditions for each target material appeared; for these conditions, also the effect of vacuum annealing was studied. The morphological, structural and optical properties were investigated by SEM, Raman spectroscopy and UV-visible-IR spectroscopy. From these observations, it emerged that the films deposited in the presence of oxygen do not show substantial differences in their morphology/structure, on the contrary of pure Ar-deposited films; thus, the trends in photoresponse can be related to differences in the defect concentration of the material, induced by depositions in the different Ar/O2 atmospheres and by annealing in Ar/H2 mixture or vacuum. In particular, the reported results suggest that some degree of oxygen shortage in the deposition process leads to a better photoelectrochemical performance, and a combination between improved charge transport and surface hydrogenation/reduction effect, leading to enhanced photoresponse, is suggested. This work elucidates the possibility of an accurate tuning of the material photoactivity by control of the deposition and annealing conditions