Osteogenesis is a complex series of events involving the differentiation of mesenchymal stem cells to generate new bone. In this study, we examined the effect of pulsed electromagnetic fields (PEMFs) on cell proliferation, alkaline phosphatase (ALP) activity, mineralization of the extracellular matrix, and gene expression in bone marrow mesenchymal stem cells (BMMSCs) during osteogenic differentiation. Exposure of BMMSCs to PEMFs increased cell proliferation by 29.6% compared to untreated cells at day 1 of differentiation. Semi-quantitative RT-PCR indicated that PEMFs significantly altered temporal expression of osteogenesis-related genes, including a 2.7-fold increase in expression of the key osteogenesis regulatory gene cbfa1, compared to untreated controls. In addition, exposure to PEMFs significantly increased ALP expression during the early stages of osteogenesis and substantially enhanced mineralization near the midpoint of osteogenesis. These results suggest that PEMFs enhance early cell proliferation in BMMSC-mediated osteogenesis, and accelerate the osteogenesis.
Objectives: For reasons of provision of highlyspecific surface area and three-dimensional culture, microcarrier culture (MC) has garnered great interest for its potential to expand anchorage-dependent stem cells. This study utilizes MC for in vitro expansion of human bone marrow mesenchymal stem cells (BMMSCs) and analyses its effects on BMMSC proliferation and differentiation. Materials and methods: Effects of semi-continuous MC compared to control plate culture (PC) and serial bead-to-bead transfer MC (MC bead-T) on human BMMSCs were investigated. Cell population growth kinetics, cell phenotypes and differentiation potential of cells were assayed. Results: Maximum cell density and overall fold increase in cell population growth were similar between PCs and MCs with similar starting conditions, but lag period of BMMSC growth differed substantially between the two; moreover, MC cells exhibited reduced granularity and higher CXCR4 expression. Differentiation of BMMSCs into osteogenic and adipogenic lineages was enhanced after 3 days in MC. However, MC bead-T resulted in changes in cell granularity and lower osteogenic and adipogenic differentiation potential. Conclusions: In comparison to PC, MC supported expansion of BMMSCs in an up-scalable threedimensional culture system using a semi-continuous process, increasing potential for stem cell homing ability and osteogenic and adipogenic differentiation.
Introduction:
Kolliphor
®
EL (K-EL) is among the most useful surfactants in the preparation of emulsions. However, it is associated with low hydrophobic drug loading in the resulting emulsified formulation.
Methods:
In this study, a formulation for intranasal administration of butylidenephthalide (Bdph), a candidate drug against glioblastoma (GBM), was prepared. Physical characteristics of the formulation such as particle size, zeta potential, conductivity, and viscosity were assessed, as well as its cytotoxicity and permeability, in order to optimize the formulation and improve its drug loading capacity.
Results:
The optimized formulation involved the integration of polyethylene glycol 400 (PEG 400) in K-EL to encapsulate Bdph dissolved in dimethyl sulfoxide (DMSO), and it exhibited higher drug loading capacity and drug solubility in water than the old formulation, which did not contain PEG 400. Incorporation of PEG 400 as a co-surfactant increased Bdph loading capacity to up to 50% (v/v), even in formulations using Kolliphor
®
HS 15 (K-HS15) as a surfactant, which is less compatible with Bdph than K-EL. The optimized Bdph formulation presented 5- and 2.5-fold higher permeability and cytotoxicity, respectively, in human GBM than stock Bdph. This could be attributed to the high drug loading capacity and the high polarity index due to DMSO, which increases the compatibility between the drug and the cell. Rats bearing a brain glioma treated with 160 mg/kg intranasal emulsified Bdph had a mean survival of 37 days, which is the same survival time achieved by treatment with 320 mg/kg stock Bdph. This implies that the optimized emulsified formulation required only half the Bdph dose to achieve an efficacy similar to that of stock Bdph in the treatment of animals with malignant brain tumor.
1,3,5-Tri-N-alkylcarbamylphloroglucinols (1-4) are synthesized as a new series of bulky inhibitors of acetylcholinesterase that may block the catalytic triad, the anionic substrate binding site, and the entrance of the enzyme simultaneously. Among three series of phloroglucinol-derived carbamates, tridentate inhibitors 1,3,5-tri-N-alkylcarbamylphloroglucinols (1-4), bidentate inhibitors 3,5-di-N-n-alkylcarbamyloxyphenols (5-8), and monodentate inhibitors 5-N-n-alkylcarbamyloxyresorcinols (9-12), tridentate inhibitors 1-4 are the most potent inhibitors of mouse acetylcholinesterase. When different n-alkylcarbamyl substituents in tridentate inhibitors 1-4 are compared, n-octylcarbamate 1 is the most potent inhibitor of the enzyme. All inhibitors 1-12 are characterized as the pseudo substrate inhibitors of acetylcholinesterase. Thus, tridentate inhibitors 1-4 are supposed to be hydrolyzed to bidentate inhibitors 5-8 after the enzyme catalysis. Subsequently, bidentate inhibitors 5-8 and monodentate inhibitors 9-12 are supposed to yield monodentate inhibitors 9-12 and phloroglucinol, respectively, after the enzyme catalysis. This means that tridentate inhibitors 1-4 may act as long period inhibitors of the enzyme. Therefore, inhibitors 1-4 may be considered as a new methodology to develop the long-acting drug for Alzheimer's disease. Automated dockings of inhibitor 1 into the X-ray crystal structure of acetylcholinesterase suggest that the most suitable configuration of inhibitor 1 to the enzyme binding is the (1,3,5)- (cis,trans,trans)-tricarbamate rotamer. The cis-carbamyl moiety of this rotamer does not bind into the acetyl group binding site of the enzyme but stretches out itself to the entrance. The other two trans-carbmayl moieties of this rotamer bulkily block the tryptophan 86 residue of the enzyme.
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