9 research outputs found
A Fractional-Order Model of Biopolyester Containing Naturally Occurring Compounds for Soil Stabilization
Currently, the use of polymers and biopolymers as soil-stabilizer additives for control of the soil degradation, deterioration, and desertification and for improving the arid and semiarid soils has been expanded significantly in the agricultural sector. This research was conducted to determine the effect of naturally occurring compounds, such as quercetin (Q) and sodium montmorillonite (NaMMt) at different weight ratios, in biopolyester, such as polylactic acid (PLA), aiming to formulate ecosustainable materials to control the soil degradation and to protect the environment. As known, the use of sophisticated analytical tools to describe the material rheology and melting properties is nowadays very popular among physicists and material scientists. Certainly, several experimental tests conducted on polymeric- and biopolymeric-based materials, such as rubbers, foams, and hydro/aero gels, show that the relaxation time spectra are a continuous function, and as a consequence, multiple relaxation times are involved in the rheological description of the materials, yielding the need for nonconventional relaxation functions. Indeed, in this work, the considered fractional-order model could be considered a powerful tool to describe and to predict the melting properties of the complex polymer-based systems containing different additives
Pro-Degradant Activity of Naturally Occurring Compounds on Polyethylene in Accelerate Weathering Conditions
In this work, naturally occurring compounds, such as Vitamin E (VE) and Ferulic Acid (FA), at high concentrations, have been considered as pro-degradant agents for Low Density Polyethylene (PE). However, all obtained results using the naturally occurring molecules as prooxidant agents for PE have been compared with the results achieved using a classical pro-oxidant agent, such as calcium stearate (Ca stearate) and with neat PE. The preliminary characterization, through rheological, mechanical and thermal analysis, of the PE-based systems highlights that the used naturally occurring molecules are able to exert a slight plasticizing action on PE and subsequently the PE rigidity and crystallinity slightly decrease, while the ductility increases. To assess the pro-degradant activity of the considered naturally occurring compounds, thin films of neat PE and PE-based systems containing 2 and 3 wt.% Ca stearate, VE and FA have been produced and subjected to accelerated weathering upon UVB light exposure. All obtained results point out that the VE and FA, at these high concentrations, exert a clear pro-oxidant activity in PE and this pro-oxidant activity is very similar to that exerted by Ca stearate. Moreover, the VE and FA at high concentrations can be considered as suitable eco-friendly pro-degradant additives for PE, also in order to control the polyolefin degradation times
Response recovery effects in Primary School children: renewal, reinstatement and spontaneous recovery. A systematic review and meta-analysis
This project will be oriented to develop a systematic review and meta-analysis, trying to analyze all the evidence on the presence of renewal, reinstatement, and spontaneous recovery on Primary School children (6-11 years old)
Development and recent progresses of gene therapy for β-thalassemia
β-thalassemias are among the most common inherited monogenic disorders worldwide due to mutations in the β-globin gene that reduce or abolish the production of the β-globin chain resulting in transfusion-dependent chronic anemia. Currently, the only curative treatment is allogeneic hematopoietic stem cells (HSCs) transplantation, but this option is limited by the a vailability of HLA-matched donor. Gene therapy, based on autologous transplantation of genetically corrected HSCs, holds the promise to treat patients lacking a compati ble bone marrow donor. I nit ial attempts of gene transfer have been unsuccessful due to limitations of available vectors to stably transfer a globin gene in HSCs and reach high and regulated expression in the erythroid progeny. With the advent of lentiviral vectors (LVs), based on human immunodeficiency virus, many of the initial limitations have been overcome. Since 2000 when Sadelain and co-workers first demonstrated successful globin gene transfer in murine thalassemia models with improvement of the phenotype using a recombinant β globin/LV, several other groups have developed different vectors encoding either β, γ or mutated globin genes and confirmed these results in both murine models and erythroid progeny derived from patient’s HSCs. In light of these encouraging results, research has recently moved into clinical trials that are ongoing or soon to begin. One participant in an ongoing gene transfer trial for β-thalassemia has achieved clinical benefit with elimination of his transfusi on re quirement. Here , dev elopmen t and recent progress of gene therapy for β-thalassemia is reviewed
Granulocyte–colony stimulating factor plus plerixafor in patients with β-thalassemia major results in the effective mobilization of primitive CD34+ cells with specific gene expression profile
Successful gene therapy for β-thalassemia requires optimal numbers of autologous gene-transduced hematopoietic stem and progenitor cells (HSPCs) with high repopulating capacity. Previous studies suggested superior mobilization in these patients by the combination of granulocyte–colony stimulating factor (G-CSF) plus plerixafor over single agents. We mobilized four adult patients using G-CSF+plerixafor to assess the intra-individual variation of the circulating CD34+ cells number and subtypes preand post-plerixafor administration. The procedure was well-tolerated and the target cell dose of ≥8×106 CD34+ cells/kg was achieved in three of them with one apheresis procedure. The addition of plerixafor unanimously increased the number of circulating CD34+ cells, and the frequency of the most primitive CD34+ subtypes: CD34+/38- and CD34+/133+/38- as well as the in vitro clonogenic potency. Microarray analyses of CD34+ cells purified from the leukapheresis of one patient mobilized twice, with G-CSF and with G-CSF+plerixafor, highlighted in G-CSF+plerixafor-mobilized CD34+ cells, higher levels of expression genes involved in HSPC motility, homing, and cell cycles. In conclusion, G-CSF+plerixafor in β-thalassemia patients mobilizes optimal numbers of HSPCs with characteristics that suggest high capacity of engraftment after transplantation.
β地中海贫血的成功基因治疗需要最佳数量具有较高再生能力的自体基因转导的造血干细胞和祖细胞(HSPC)。之前的研究表明,与单药相比,通过组合粒细胞集落刺激因子(G-CSF)加普乐沙福在这些患者中有出色的动员作用。我们使用G-CSF+普乐沙福对四例成年患者进行了动员,以评估服用普乐沙福之前和之后的循环CD34+细胞数量和亚型的个体内差异。这种方式的耐受性好,其中的三例患者仅通过一次分离技术即获得≥8×106 CD34+细胞/kg的细胞采集目标。加用普乐沙福毫无例外地增加了循环CD34+细胞的数量和最原始CD34+亚型(CD34+/38-和CD34+/133+/38+)的频率以及体外克隆效力。一例血细胞分离术中纯化的CD34+细胞微阵列分析(患者使用G-CSF和G-CSF+普乐沙福动员两次)强调,在G-CSF+普乐沙福动员的CD34+细胞中,有更高水平的表达基因牵涉到HSPC运动性、归巢和细胞周期。总之,G-CSF+普乐沙福在β地中海贫血病患者中可以动员最优数量的HSPC,具有移植后的移植成活率高的特征
The Challenge of Using CB-HSCs As Source for Gene Therapy: Lentiviral Vector Transduction, Phenotypic Characterization and Global Gene Expression Profile of Ex-Vivo Expanded CB CD34+ Cells
Introduction: Genetic modification of autologous hematopoietic stem and progenitor cells (HSPC) is a promising clinical intervention to cure inherited monogenic diseases. Successful gene therapy trials have already been conducted using CD34+ cells from bone marrow and from mobilized peripheral blood. In this regard, cord blood (CB) represents an attractive source of HSCs due to its high concentration of high proliferative HSPC and increased susceptibility to be transduced by lentiviral vectors. Unfortunately, the major disadvantage is the limited number of HSC in the CB collection. Consequently, ex-vivo expansion of CB-HSC is desirable to extend clinical applications.
Purposes: To investigate the ability of UCB-cd34+ cells to be expanded in serum-free media supplemented with the early acting hematopoietic cytokines SCF,TPO and Flt-3 ligant (STF) and to characterize CD34+ cells subtypes, clonogenic capacity and gene expression profile during expansion. We also wanted to investigate the susceptibility of the expanded cd34+ cells to be transduced by a GFP-lentiviral vector (LV-GFP)
Material and Methods: CD34+ immunoselected cells from 10 UCB were grown for 8 days in customized serum-free medium formulated for HSC expansion, supplemented with STF cytokines. Numbers end frequency of CD34+cells and co-expression of the primitive surface antigens (CD38, CD133, CD90) was evaluated during expansion. Colonies developed in methylcellulose were scored for enumeration ad typing.
LV-GFP transduction efficiency was evaluated in CD34+ cells cultured for 4 days in expansion medium plus STF and for 24 hrs in X-vivo10 medium with STF±IL-3 cytokines; the last condition slightly expands CD34+ cells (1.3 fold) and are currently used for HSPC-lentivector transduction in gene therapy clinical trials.
The transduction efficiency was evaluated by measuring the percentage of GFP+ cells in the bulk and in colonies developed in methylcellulose and the VCN/cell by Q-PCR.
Gene expression profiles were analyzed by human whole genome Agilent microarray Technology to detect differentially expressed genes between expanded, ex-vivo medium cultured and un-cultured cells.
Results: We found an average of 8 fold-increase CD34+cells at day 4 and of 22 fold- increase at day 8 of culture. The frequency of CD34+ was maintained at day 4 and declined of about 50% at day 8. CD34+/CD38- early progenitors doublet as early as day 4, differences in CD34+/CD133+ and CD34+/CD90+cells were not significant.
The number of CFU slightly increased during expansion while the relative frequency of colonies type did not significantly changed.
Four days expanded CD34+ cells were transduced more efficiently than those grown in ex-vivo medium even in presence of IL-3 added to the STF cytokine cocktail.
Comprehensive gene expression profile analysis highlighted about 4000 genes differentially expressed in CD34+ cells expanded for 4 and for 8 days compared to that of the un-cultured cells. Conversely, the expression profiles analysis did not show any clear separation between different cell culture methods (expansion vs ex-vivo medium). Specifically, the number of differentially expressed genes in common between the different culture conditions compared with the un-cultured cells was statistically significant. Unsurprisingly, the common up-regulated genes were related to the cell cycle. The likeness between the gene expression profiles of the different culture conditions was also validated by the identification of a significantly small number of differentially expressed genes between them.
Conclusions: UCB-CD34+ cells can be efficiently expanded and transduced in serum free conditions. The expanded cells exhibited phenotypic marchers typical of early progenitors and developed colonies in number and in type similar to the unmanipulated cells and exhibited whole gene expression profile that is consisted with that of CD34+ cells exposed for the short term culture conditions currently used in gene therapy trial mediated by lentiviral vectors.
Results from this study open a window on the future possibility of using homologous UCB-HSC as target for gene correction in patients diagnosed for a genetic disorder in prenatal time.
The genetically modified cells would be stored and used for gene therapy in the same individual in pediatric age.
This work was funded by the F and P Cutino Foundation - Project RiMedRi CUP G73F1200015000