BIOCOMPATIBILITY AND BIODEGRADABILITY OF ELECTROSPUN PHEA-PLA SCAFFOLDS: OUR PRELIMINARY EXPERIENCE IN A MURINE ANIMAL MODEL

We obtained a nano-fibrillar scaffold starting from a polymeric solution which, through electrospinning, gave a biodegradable material with optimal mechanical features and the capacity to allow cell adhesion. In this paper we report the in-vivo application on a murine animal model of two electrospun biodegradable materials, specifically designed to create tubular structures. In one case PHEA-PLA was co-spun with silk fibroin (Fibro-PHEAPLA) by a parallel electrospinning process to obtain a scaffold with two different polymeric fibers. In the other case, PHEA-PLA was mixed with polycaprolactone (PCLPHEA-PLA) to obtain a hybrid fibers scaffold. The in-vitro assay showed fibroblast colonization in both materials. The scaffolds were implanted in the dorsal fascial pouch of rats to evaluate their in-vivo Biocompatibility and tissue integration. Histopathological findings showed that after implantation a neutrophilic reaction associated to colliquative necrosis was predominant, particularly for PCL-PHEA-PLA. Fibro-PCL-PHEA caused a non organized stromal reaction. Cell adhesion was confirmed at SEM scan. Both materials were totally absorbed after 40 days with an inflammatory reaction. This preliminary study showed that biocompatibility of the scaffolds needs further investigation. The capability of the materials to be functionalized could allow us to modulate the inflammatory host response

Nicotinamide alone accelerates the conversion of mouse embryonic stem cells into mature neuronal populations.

Vitamin B3 has been shown to play an important role during embryogenesis. Specifically, there is growing evidence that nicotinamide, the biologically active form of vitamin B3, plays a critical role as a morphogen in the differentiation of stem cells to mature cell phenotypes, including those of the central nervous system (CNS). Detailed knowledge of the action of small molecules during neuronal differentiation is not only critical for uncovering mechanisms underlying lineage-specification, but also to establish more effective differentiation protocols to obtain clinically relevant cells for regenerative therapies for neurodegenerative conditions such as Huntington's disease (HD). Thus, this study aimed to investigate the potential of nicotinamide to promote the conversion of stem cells to mature CNS neurons. METHODS: Nicotinamide was applied to differentiating mouse embryonic stem cells (mESC; Sox1GFP knock-in 46C cell line) during their conversion towards a neural fate. Cells were assessed for changes in their proliferation, differentiation and maturation; using immunocytochemistry and morphometric analysis methods. RESULTS: Results presented indicate that 10 mM nicotinamide, when added at the initial stages of differentiation, promoted accelerated progression of ESCs to a neural lineage in adherent monolayer cultures. By 14 days in vitro (DIV), early exposure to nicotinamide was shown to increase the numbers of differentiated βIII-tubulin-positive neurons. Nicotinamide decreased the proportion of pluripotent stem cells, concomitantly increasing numbers of neural progenitors at 4 DIV. These progenitors then underwent rapid conversion to neurons, observed by a reduction in Sox 1 expression and decreased numbers of neural progenitors in the cultures at 14 DIV. Furthermore, GABAergic neurons generated in the presence of nicotinamide showed increased maturity and complexity of neurites at 14 DIV. Therefore, addition of nicotinamide alone caused an accelerated passage of pluripotent cells through lineage specification and further to non-dividing mature neurons. CONCLUSIONS: Our results show that, within an optimal dose range, nicotinamide is able to singly and selectively direct the conversion of embryonic stem cells to mature neurons, and therefore may be a critical factor for normal brain development, thus supporting previous evidence of the fundamental role of vitamins and their metabolites during early CNS development. In addition, nicotinamide may offer a simple effective supplement to enhance the conversion of stem cells to clinically relevant neurons

PEGYLATED POLYASPARTAMIDE\u2013POLYLACTIDE BASED NANOPARTICLES PENETRATING CYSTIC FIBROSIS ARTIFICIAL MUCUS

Here, the preparation of mucus-penetrating nanoparticles for pulmonary administration of ibuprofen in patients with cystic fibrosis is described. A fluorescent derivative of \u3b1,\u3b2-poly(N-2-hydroxyethyl)-D,L-aspartamide is synthesized by derivatization with rhodamine, polylactide, and poly(ethylene glycol), to obtain polyaspartamide 12 polylactide derivatives with different degrees of pegylation. Starting from these copolymers, fluorescent nanoparticles with different poly(ethylene glycol) content, empty and loaded with ibuprofen, showed spherical shape, colloidal size, slightly negative \u3b6 potential, and biocompatibility toward human bronchial epithelial cells. The high surface poly(ethylene glycol) density of fluorescent nanoparticles and poly(ethylene glycol) brush-like conformation assumed on their surface, conferred to pegylated nanoparticles the mucus-penetrating properties, properly demonstrated by assessing their ability to avoid interactions with mucus components and to penetrate cystic fibrosis artificial mucus. Finally, ibuprofen release profile and uptake capacity within human bronchial epithelial cells in the presence of cystic fibrosis artificial mucus showed how these mucus-penetrating nanoparticles could rapidly diffuse through the mucus barrier reaching the mucosal surface, where they could offer a sustained delivery of ibuprofen at the site of disease

Improvements in Rational Design Strategies of Inulin Derivative Polycation for siRNA Delivery

The advances of short interfering RNA (siRNA)-mediated therapy provide a powerful option for the treatment of many diseases, including cancer, by silencing the expression of targeted genes involved in the progression of the pathology. On this regard, a new pH-responsive polycation derived from inulin, Inulin-g-imidazole-g-diethylenetriamine (INU-IMI-DETA), was designed and employed to produce INU-IMI-DETA/siRNA “Inulin COmplex Nanoaggregates” (ICONs). The experimental results showed that INU-IMI-DETA exhibited strong cationic characteristics and high solubility in the pH range 3−5 and selfaggregation triggered by pH increase and physiological salt concentration. INUIMI- DETA showed as well a high buffering capacity in the endosomal pH range of 7.4−5.1. In the concentration range between 25 and 1000 μg/mL INU-IMI-DETA had no cytotoxic effect on breast cancer cells (MCF-7) and no lytic effect on human red blood cells. ICONs were prepared by two-step procedure involving complexation and precipitation into DPBS buffer (pH 7.4) to produce siRNA-loaded nanoaggregates with minimized surface charge and suitable size for parenteral administration. Bafilomycin A1 inhibited transfection on MCF-7 cells, indicating that the protonation of the imidazole groups in the endolysosome pathway favors the escape of the system from endolysosomal compartment, increasing the amount of siRNA that can reach the cytoplasm