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Summary: To better understand the association between high salt intake and osteoporosis, we investigated the effect of sodium chloride (NaCl) on mice and human osteoclastogenesis. The results suggest a direct, activating role of NaCl supplementation on bone resorption. Introduction: High NaCl intake is associated with increased urinary calcium elimination and parathyroid hormone (PTH) secretion which in turn stimulates the release of calcium from the bone, resulting in increased bone resorption. However, while calciuria after NaCl loading could be shown repeatedly, several studies failed to reveal a significant increase in PTH in response to a high-sodium diet. Another possible explanation that we investigated here could be a direct effect of high-sodium concentration on bone resorption. Methods: Mouse bone marrow macrophage and human peripheral blood mononuclear cells (PBMC) driven towards an osteoclastogenesis pathway were cultivated under culture conditions mimicking hypernatremia environments. Results: In this study, a direct effect of increased NaCl concentrations on mouse osteoclast differentiation and function was observed. Surprisingly, in a human osteoclast culture system, significant increases in the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, calcitonin receptor (CTR)-positive osteoclasts, nuclear factor-activated T cells c1 ( NFATc1) gene expression, and areal and volumetric resorptions were observed for increasing concentrations of NaCl. This suggests a direct, activating, cell-mediated effect of increased concentrations of NaCl on osteoclasts. Conclusions: The reported that enhanced bone resorption after high-sodium diets may not only be secondary to the urinary calcium loss but may also be a direct, cell-mediated effect on osteoclastic resorption. These findings allow us to suggest an explanation for the clinical findings independent of a PTH-mediated regulation. [ABSTRACT FROM AUTHOR]

Survivin orchestrates intracellular pathways during cell division and apoptosis. Its central function as mitotic regulator and inhibitor of cell death has major implications for tumor cell proliferation. Analyses in early-branching Metazoa so far propose an exclusive role of survivin as a chromosomal passenger protein, whereas only later during evolution a complementary antiapoptotic function might have arisen, concurrent with increased organismal complexity. To lift the veil on the ancestral function(s) of this key regulator, a survivin-like protein (SURVL) of one of the earliest-branching metazoan taxa was identified and functionally characterized. SURVL of the sponge Suberites domuncula shares considerable similarities with its metazoan homologs, ranging from conserved exon/intron structure to presence of protein-interaction domains. Whereas sponge tissue shows a low steady-state level, SURVL expression was significantly upregulated in rapidly proliferating primmorph cells. In addition, challenge of tissue and primmorphs with heavy metal or lipopeptide stimulated SURVL expression, concurrent with the expression of a newly discovered caspase. Complementary functional analyses in transfected HEK-293 cells revealed that heterologous expression of a SURVL-EFGP fusion not only promotes proliferation but also enhances resistance to cadmium-induced cell death. Taken together, these results suggest both a deep evolutionary conserved dual role of survivin and an equally conserved central position in the interconnected pathways of cell cycle and apoptosis. [ABSTRACT FROM AUTHOR]

Highlights • HVOF coatings had more stable phases, more cracks and less roughness compared to the flame sprayed coating. • The corrosion resistance of the HVOF was higher than flame sprayed coatings. • In the flame sprayed samples, corrosion products formed a protective layer that increased corrosion resistance over time. Abstract Hydroxyapatite coatings are biocompatible, osteoconductive and create a corrosion resistance surface on magnesium-based implants. Thermal decomposition of HA during thermal spraying limits its application. To overcome the challenges associated with thermal decomposition of HA during thermal spraying, high velocity oxygen fuel spraying with a good thermal stability for HA is proposed. In this work, the traditional flame spraying was compared to high velocity oxy-fuel (HVOF) for HA depositions on magnesium alloy substrates. The effect of process on microstructure, morphology, corrosion behavior and cellular response of HA layers were evaluated. X-ray diffraction analysis showed that the amount of secondary phases in the HVOF deposited sample was less than that in the flame sprayed coatings. Elemental weight percentage of calcium in corroded surfaces was 21% and 34.5% for HVOF and flame sprayed coatings, respectively. Contrary to the results of the electrochemical impedance spectroscopy measurements for HVOF coating performed during the early hours of immersion in the simulated body fluid (SBF), flame sprayed coating exhibited lower corrosion rate after 5 h immersion in SBF solution. [ABSTRACT FROM AUTHOR]

The close match of stiffness between implant material and bone is critically important to avoid stress-shielding effect and ensure a fast healing of injured tissues. Here, we introduce liquid metal dealloying method for synthesis of robust open porous biomaterials possessing low Young's modulus. The remarkable advantage of the liquid metal dealloying method is a large flexibility in selecting chemical composition of a desired porous biomaterial together with unique tunable microstructure. To demonstrate the versatility of the method, a number of open porous Ti x Zr 100-x alloys with different chemical compositions and microstructural characteristics was developed by dealloying precursor (Ti x Zr 100-x ) y Cu 100-y alloys in liquid magnesium. The effects of the processing conditions and the precursors' chemical composition on the microstructure of the porous Ti x Zr 100-x as well as their mechanical behavior were discussed in detail. In particular, the porous Ti x Zr 100-x distinguish themselves due to a low and tunable stiffness ranging from 3.2 to 15.1 GPa and a rather high strength reaching up to 480 MPa. This unique combination of mechanical properties of the new open porous Ti x Zr 100-x alloys becomes even more interesting in view of preliminary biological tests highlighting their excellent cytocompatibility. Overall, the liquid metal dealloying provides an opportunity for designing a new biomaterials platform with flexible tunable functionality. [ABSTRACT FROM AUTHOR]

Abstract: During the transfer of rainbow trout from freshwater to seawater, the gills have to switch from an ion-absorption epithelium to an ion-secretion epithelium in order to maintain equilibrium of their hydromineral balance. After a change to ambient salinity, several gill modifications have already been demonstrated, including ion transporters. In order to identify new branchial mechanisms implicated in seawater acclimation, we carried out an extensive analysis of gene expression in gills using microarray technology. This strategy allowed us to show that CYP1A gene expression was up-regulated in the gills after salinity transfer. This increase was confirmed by real-time reverse transcription PCR. Furthermore, measurements of CYP1A enzyme activity (EROD) showed a significant increase after transfer to seawater. Immunohistochemistry analysis in the gills revealed that cells with a higher expression of CYP1A protein were principally pillar cells and those in the primary lamellae not in contact with the external medium. The results of this study suggest for the first time that CYP1A may be implicated in the seawater acclimation of the gills of rainbow trout. [Copyright &y& Elsevier]