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Aim: The osteogenic potential of new premixed calcium‐silicate‐containing bioceramic sealers (Ca‐Si sealers) was tested with porcine vascular wall‐mesenchymal stem cells (pVW‐MSCs). Methodology: Two Ca‐Si‐containing sealers: Ceraseal (MetaBiomed, Cheong‐si, South Korea) and AH Plus Bioceramic (Maruchi, Wonju‐si, South Korea), and an epoxy resin sealer (AH Plus; Dentsply, Konstanz, Germany) as a control, were prepared according to the manufacturers' indications. All samples were allowed to set for 100% of their setting time in a sterile humid cabinet at 37°C and 95% relative humidity. pVW‐MSC seeding efficiency and osteogenic differentiation were analysed as marker of gene/protein expression for up to 12 days. Mineralization assay and immunofluorescence staining were performed and evaluated over a period of 21 days. Statistical analyses were conducted using one‐way analysis of variance (p <.05). Additional samples were prepared and stored under the same conditions and inspected using an environmental scanning electron microscope equipped with an energy dispersive X‐ray spectroscopy system. Results: Significantly higher cell seeding efficiency (p <.05) was observed for both Ca‐Si sealers from day 8. pVW‐MSCs showed a significant shift towards the osteogenic lineage only when seeded in contact with Ca‐Si sealers. Gene expression of osteopontin was upregulated significantly. Collagen I and osteocalcin were clearly expressed by cells in contact with Ca‐Si sealers. Mineralization granules were observed in Alizarin red assays and confocal laser scanning microscopy analysis of both Ca‐Si sealers. No gene expression or granule mineralization were observed on the epoxy resin sealer. Conclusions: Premixed Ca‐Si sealers displayed a higher potential for osteogenic activity on pVW‐MSCs. Epoxy resin sealer was unable to induce any osteogenic activity. The properties of both Ca‐Si sealers suggest their potential as osteoinductive platforms for vascular MSCs in periapical bone. [ABSTRACT FROM AUTHOR]

The properties of the mitochondrial F1FO‐ATPase catalytic site, which can bind Mg2+, Mn2+, or Ca2+ and hydrolyze ATP, were explored by inhibition kinetic analyses to cast light on the Ca2+‐activated F1FO‐ATPase connection with the permeability transition pore (PTP) that initiates cascade events leading to cell death. While the natural cofactor Mg2+ activates the F1FO‐ATPase in competition with Mn2+, Ca2+ is a noncompetitive inhibitor in the presence of Mg2+. Selective F1 inhibitors (Is‐F1), namely NBD‐Cl, piceatannol, resveratrol, and quercetin, exerted different mechanisms (mixed and uncompetitive inhibition) on either Ca2+‐ or Mg2+‐activated F1FO‐ATPase, consistent with the conclusion that the catalytic mechanism changes when Mg2+ is replaced by Ca2+. In a partially purified F1 domain preparation, Ca2+‐activated F1‐ATPase maintained Is‐F1 sensitivity, and enzyme inhibition was accompanied by the maintenance of the mitochondrial calcium retention capacity and membrane potential. The data strengthen the structural relationship between Ca2+‐activated F1FO‐ATPase and the PTP, and, in turn, on consequences, such as physiopathological cellular changes. [ABSTRACT FROM AUTHOR]

The link between metabolic remodeling and stem cell fate is still unclear. To explore this topic, the metabolic profile of porcine vascular wall mesenchymal stem cells (pVW‐MSCs) was investigated. At the first and second cell passages, pVW‐MSCs exploit both glycolysis and cellular respiration to synthesize adenosine triphosphate (ATP), but in the subsequent (third to eighth) passages they do not show any mitochondrial ATP turnover. Interestingly, when the first passage pVW‐MSCs are exposed to 0.1 or 10 μg/ml lipopolysaccharides (LPSs) for 4 hr, even if ATP synthesis is prevented, the spare respiratory capacity is retained and the glycolytic capacity is unaffected. In contrast, the exposure of pVW‐MSCs at the fifth passage to 10 μg/ml LPS stimulates mitochondrial ATP synthesis. Flow cytometry rules out any reactive oxygen species (ROS) involvement in the LPS effects, thus suggesting that the pVW‐MSC metabolic pattern is modulated by culture conditions via ROS‐independent mechanisms. [ABSTRACT FROM AUTHOR]