Dexamethasone loaded multi-layer poly-l-lactic acid/pluronic P123 composite electrospun nanofiber scaffolds for bone tissue engineering and drug delivery.

In tissue engineering, it is common to mix drugs that can control proliferation and differentiation of cells into polymeric solutions as part of composite to get bioactive scaffolds. However, direct incorporation of drugs might potentially result in undesired burst release. To overcome this problem, here we developed electrospun multilayer drug loaded poly-l-lactic acid/pluronic P123 (PLLA-P123) composite scaffolds. The drug was loaded into the middle layer. The surface, the mechanical and physiochemical properties of the scaffolds were evaluated. The drug release profiles were monitored. Finally, the osteogenic proliferation and differentiation potential were determined. The scaffolds fabricated here have appropriate surface properties, but with different mechanical strength and osteogenic proliferation and differentiation. Multi-layer scaffolds where the drug was in the middle layer and PLLA-plasma and PLLA-P123 with cover layer showed the best osteogenic proliferation and differentiation than the other groups of scaffolds. The drug release profiles of the scaffolds were completely different: single layer scaffolds showed burst release within the first day, while multilayer scaffolds showed controlled release. Therefore, the multilayer drug loaded scaffolds prepared have dual benefits can provide both better osteogenesis and controlled release of drugs and bioactive molecules at the implant site.

Application of Response Surface Method for Preparation, Optimization, and Characterization of Nicotinamide Loaded Solid Lipid Nanoparticles.

Purpose: Solid lipid nanoparticles (SLNs) have been proven to possess pharmaceutical advantages. They have the ability to deliver hydrophilic drugs through lipid membranes of the body. However, the loading of such drugs into SLNs is challenging. Hydrophilic nicotinamide, a histone deacetylase inhibitor, is used to establish SLNs with enhanced encapsulation efficiency by using statistical design. Methods: The possible effective parameters of these particles' characteristics were determined using pre-formulation studies and preliminary tests. Afterwards, the Response Surface Method (RSM) was utilized to optimize the preparation condition of SLNs. The effect of the amount of lipid, drug, surfactant, and the mixing apparatus were studied on particle size, zeta potential, and encapsulation efficiency of the obtained particles. The acquired particles were characterized in respect of their morphology, in vitro release profile, and cytotoxicity. Results: According to this study, all the dependant variables could be fitted into quadratic models. Particles of 107 nm with zeta potential of about -40.9 and encapsulation efficiency of about 36% were obtained under optimized preparation conditions; i.e. with stearic acid to phospholipon® 90G ratio of 7.5 and nicotinamide to sodium taurocholate ratio of 14.74 using probe sonication. The validation test confirmed the model's suitability. The release profile demonstrated the controlled release profile following the initial burst release. Neither the nicotinamide nor the SLNs showed toxicity under the evaluated concentrations. Conclusion: The acquired results suggested the suitability of the model for designing the delivery system with a highly encapsulated water soluble drug for controlling its delivery.

G-CSF loaded nanofiber/nanoparticle composite coated with collagen promotes wound healing in vivo.

Sustained release of functional growth factors can be considered as a beneficial methodology for wound healing. In this study, recombinant human granulocyte colony-stimulating factor (G-CSF)-loaded chitosan nanoparticles were incorporated in Poly(ε-caprolactone) (PCL) nanofibers, followed by surface coating with collagen type I. Physical and mechanical properties of the PCL nanofibers containing G-CSF loaded chitosan nanoparticles PCL/NP(G-CSF) and in vivo performance for wound healing were investigated. G-CSF structural stability was evaluated through SDS_PAGE, reversed phase (RP) HPLC and size-exclusion chromatography, as well as circular dichroism. Nanofiber/nanoparticle composite scaffold was demonstrated to have appropriate mechanical properties as a wound dresser and a sustained release of functional G-CSF. The PCL/NP(G-CSF) scaffold showed a suitable proliferation and well-adherent morphology of stem cells. In vivo study and histopathological evaluation outcome revealed that skin regeneration was dramatically accelerated under PCL/NP(G-CSF) as compared with control groups. Superior fibroblast maturation, enhanced collagen deposition and minimum inflammatory cells were also the beneficial properties of PCL/NP(G-CSF) over the commercial dressing. The synergistic effect of extracellular matrix-mimicking nanofibrous membrane and G-CSF could develop a suitable supportive substrate in order to extensive utilization for the healing of skin wounds. © 2017 Wiley Periodicals Inc. J Biomed Mater Res Part A: 105A: 2830-2842, 2017.

Expression of liver alpha-amylase in obese mouse hepatocytes.

AIM: The aim of this study is to demonstrate the relation between the expression of liver alpha-amylase and obesity. BACKGROUND: Alpha-amylase catalyses the hydrolysis of 1, 4-alpha-glucosidic linkages in polysaccharides and has three main subtypes, including: salivary, pancreatic, and hepatic. Hepatic alpha-amylase is involved in glycogen metabolism, and has a role in obesity and its management. In this study, we aimed to analyze the expression of liver alpha-amylase in overweight and obese mouse. MATERIAL AND METHODS: In this study, NMRI male mice were randomly divided into two groups. The sample group (obese) took a high-fat and carbohydrate diet, while the control group (normal) took a laboratory pellet chow for eight weeks. During this period, their weight was measured. After eight weeks, liver hepatocytes were isolated using an enzymatic digestion method. Immunocytochemistry (ICC) and flow cytometry analysis were performed to measure alpha amylase protein expression in mouse liver hepatocyte cells. RESULTS: A significant difference in the body weight was observed between the two groups (p<0.05). The qualitative protein expression of liver alpha-amylase was found to be higher in the obese group in both tests (immunocytochemistry and flow cytometry). Animals from the test group presented higher alpha-amylase expression, which suggests that this hepatic protein may constitute a potential indicator of susceptibility for fat tissue accumulation and obesity. The present data demonstrates an increased expression of liver amylase in obese mice. CONCLUSION: These results suggest that liver amylase secretion might be useful for predicting susceptibility to obesity induced by consumption of a high-fat and carbohydrate diet.

Amniotic membrane mesenchymal stem cells can differentiate into germ cells in vitro.

This is the first report on differentiation of mouse amniotic membrane mesenchymal stem cells (AM-MSCs) into male germ cells (GCs). AM-MSCs have the multipotent differentiation capacity and can be differentiated into various cell types. In the present study, AM-MSCs were induced for differentiation into GCs. AM-MSCs were isolated from mouse embryonic membrane by enzymatic digestion. AM-MSCs were characterized with osteogenic and adipogenic differentiation test and flow cytometric analysis of some CD-markers. AM-MSCs were induced to differentiate into GCs using a creative two-step method. Passage-3 AM-MSCs were firstly treated with 25 ng/ml bone morphogenetic protein 4 (BMP4) for 5 d and in continuing with 1 µM retinoic acid (RA) for 12 d (total treatment time was 17 d). At the end of the treatment period, real-time reverse transcription (RT)-PCR was performed to evaluate the expression of GC-specific markers-Itgb1, Dazl, Stra8, Piwil2, Mvh, Oct4, and c-Kit- in the cells. Moreover, flow cytometry and immunofluorescence staining were performed to evaluate the expression of Mvh and Dazl at protein level. Real-time RT-PCR showed that most of the tested markers were upregulated in the treated AM-MSCs. Furthermore, flow cytometric and immunofluorescence analyses both revealed that a considerable part of the treated cells expressed GC-specific markers. The percentage of positive cells for Mvh and Dazl was about 23 and 46%, respectively. Our results indicated that a number of AM-MSCs successfully differentiated into the GCs. Finally, it seems that AM-MSCs would be a potential source of adult pluripotent stem cells for in vitro generation of GCs and cell-based therapies for treatment of infertility.