Biodegradable composite porous poly(dl-lactide-co-glycolide) scaffold supports mesenchymal stem cell differentiation and calcium phosphate deposition

In recent decades, tissue engineering strategies have been proposed for the treatment of musculoskeletal diseases and bone fractures to overcome the limitations of the traditional surgical approaches based on allografts and autografts. In this work we report the development of a composite porous poly(dl-lactide-co-glycolide) scaffold suitable for bone regeneration. Scaffolds were produced by thermal sintering of porous microparticles. Next, in order to improve cell adhesion to the scaffold and subsequent proliferation, the scaffolds were coated with the osteoconductive biopolymers chitosan and sodium alginate, in a process that exploited electrostatic interactions between the positively charged biopolymers and the negatively charged PLGA scaffold. The resulting scaffolds were characterized in terms of porosity, degradation rate, mechanical properties, biocompatibility and suitability for bone regeneration. They were found to have an overall porosity of 3c85% and a degradation half time of 3c2\u2009weeks, considered suitable to support de novo bone matrix deposition from mesenchymal stem cells. Histology confirmed the ability of the scaffold to sustain adipose-derived mesenchymal stem cell adhesion, infiltration, proliferation and osteo-differentiation. Histological staining of calcium and microanalysis confirmed the presence of calcium phosphate in the scaffold sections

The impact of nitric oxide on calcium homeostasis in PE/CA-PJ15 cells.

Nitric oxide (NO) production and Ca2+ homeostasis are key determinants for the control of many cell functions. NO is known to be a mediator of Ca2+ homeostasis in a highly complex and cell-specific manner and although Ca2+ homeostasis has been explored in human oral cancer cells, the exact mechanisms are not completely understood. In this study we investigated the impact of exogenous NO on [Ca2+]c homeostasis in PE/CA-PJ15 cells. DESIGN: Cells were treated with S-nitrosocysteine as NO-donor and the determinations of cytosolic Ca2+ concentrations were performed using FURA-2 AM. Carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) and oligomycin were used to challenge mitochondrial functionality, whereas thapsigargin (TG) and La3+ were employed to perturb intracellular calcium levels. RESULTS: NO derived from S-nitrosocysteine (CySNO) induced a dose-dependent reduction of cytosolic calcium [Ca2+]c whereas oxy-haemoglobin (oxyHb) completely counteracted this effect. Subsequently, we assessed possible relationships between NO and cellular structures responsible for Ca2+ homeostasis. We found that uncoupling of mitochondrial respiration with carbonyl-cyanide-4-(trifluoromethoxy)-phenylhydrazone (FCCP) and oligomycin strongly reduced the effect of NO on [Ca2+]c. Moreover, we found that during this mitochondrial energetic deficit, the effect of NO on [Ca2+]c was also reduced in the presence of La3+ or thapsigargin. CONCLUSIONS: NO induces a concentration-dependent [Ca2+]c reduction in PE/CA-PJ15 human oral cancer cells and potentiates mitochondrial Ca2+ buffering in the presence of TG or La3+. Further, we show that exogenous NO deregulates Ca2+ homeostasis in PE/CA-PJ15 cells with fully energized mitochondria

Enamel matrix proteins and their application in bone tissue regeneration. A Review.

Current treatment options for skeletal repair (alloplastic materials, bone grafts, etc.) bave significant limitations, especially in elderly subjects. However, bone tissue engineering seems to provide a solution for reconstructing criticai size bone defects. Many of thè current regenerative medicine solutions developed rely on products that combine biological agents, such as cells or biomolecules (1). In dentistry, Enamel matrix proteins (EMP) bave been successfully employed to promote wound healing of severe infrabony periodontal defects with regeneration of periodontal ligament, cementimi and alveolar bone (2-4). The purpose of this review is to evaluate thè ability of enamel matrix proteins to promote bone tissue formation and shed light on their possible application in skeletal regenerative medicine. A systematic literature search in electronic databases (PubMed and Cochrane Library) was conducted, using thè following search term combination: 'Amelogenins' or 'Enamel Matrix Proteins' or 'Enamel Matrix Derivative' and Osteoblast' or 'Bone' or 'Mineralized Tissue' or 'Tissue Regeneration'. Publications were considered for systematic review if they were published beforel January 2015 in English language and were Hsted as reference in selected articles. Articles were excluded ìf they were without histomorphometric analysis or quantitative analysis of calcium deposits in vitro, written in languages other than English, clinical and/or animai periodontal regeneration studies, in vivo and in vitro tooth/root developmental studies (with ameloblasts or cementoblasts or odontoblast). Assessment of thè methodological quality of thè studies and data extraction were carried out by three authors. A total of 405 articles were found. Only 23 publications, 15 in vìvo and 8 in vitro studies, respected thè inclusion criteria and were used for this review. The EMD osteoinductive property appears to be questionable and unclear if thè produci is used in bone tissue regeneration. In thè in vivo reviewed articles, thè best results were recorded in thè presence of restraints and not in large or criticai size defects, whereas EMD showed some osteopromotion in thè early healing phases. Encouraging data are given on thè use of Synthetic Peptide (SP) and recombinant amelogenins. Based on these data, it is necessary to carry out further investigation usìng amelogeninbased compounds or with their active peptides with known composition and concentration. This would help to standardize thè results by increasing thè effectiveness of thè work in order to better clarify thè role and thè possible applications of amelogenins in bone tissue regeneration

Effects of Vitamin C on Fibroblasts from Sporadic Alzheimer’s Disease Patients

Several therapies for Alzheimer's Disease (AD) are currently under investigation. Some studies have reported that concentration of vitamins in biological fluids are lower in AD patients compared to control subjects and clinical evidence has shown the therapeutic potential of vitamin C and E in delaying AD progression. However, the molecular mechanism(s) that are engaged upon their administration in the APP metabolism in vitro or in vivo still need clarifying. Here, we investigate the effects of vitamin C supplementation, at physiological concentration, in skin fibroblasts obtained from SAD and FAD patients. This study shows that SAD patients' fibroblasts exhibited the exclusive appearance of C-terminal fragments, derived from APP processing, without giving rise to the beta-amyloid peptide, other than corresponding decreased levels of lysosomal enzymes, such as beta-hexosaminidase, alpha-mannosidase and cathepsins B, L, and D

Nitric oxide depletion alters hematopoietic stem cell commitment toward immunogenic dendritic cells

NO* is a key molecule involved in the regulation of cell survival, proliferation and differentiation in many cell types. In this study we investigated the contribution of NO* during the differentiation of human peripheral blood hemopoietic stem cells (CD34+HSCs) toward immunogenic dendritic cells (i-DCs)