Induction of osteogenic markers in differentially treated cultures of embryonic stem cells

<p>Abstract</p> <p>Background</p> <p>Facial trauma or tumor surgery in the head and face area often lead to massive destruction of the facial skeleton. Cell-based bone reconstruction therapies promise to offer new therapeutic opportunities for the repair of bone damaged by disease or injury. Currently, embryonic stem cells (ESCs) are discussed to be a potential cell source for bone tissue engineering. The purpose of this study was to investigate various supplements in culture media with respect to the induction of osteogenic differentiation.</p> <p>Methods</p> <p>Murine ESCs were cultured in the presence of LIF (leukemia inhibitory factor), DAG (dexamethasone, ascorbic acid and β-glycerophosphate) or bone morphogenetic protein-2 (BMP-2). Microscopical analyses were performed using von Kossa staining, and expression of osteogenic marker genes was determined by real time PCR.</p> <p>Results</p> <p>ESCs cultured with DAG showed by far the largest deposition of calcium phosphate-containing minerals. Starting at day 9 of culture, a strong increase in collagen I mRNA expression was detected in the DAG-treated cells. In BMP-2-treated ESCs the collagen I mRNA induction was less increased. Expression of osteocalcin, a highly specific marker for osteogentic differentiation, showed a double-peaked curve in DAG-treated cells. ESCs cultured in the presence of DAG showed a strong increase in osteocalcin mRNA at day 9 followed by a second peak starting at day 17.</p> <p>Conclusion</p> <p>Supplementation of ESC cell cultures with DAG is effective in inducing osteogenic differentiation and appears to be more potent than stimulation with BMP-2 alone. Thus, DAG treatment can be recommended for generating ESC populations with osteogenic differentiation that are intended for use in bone tissue engineering.</p

Effect of Fluoride on Hypervitaminosis D in Rats

SYNOPSIS IN INTERLINGUA LE EFFECTO DE FLUORURO SUPER HYPERVITAMINOSIS D IN RATTOS.-Esseva usate rattos recipiente 0,2 mg de fluoruro per die (i.e., approximativemente le ingestion physiologic pro le ratto), rattos recipiente doses toxic de vitamina D, rattos recipiente vitamina D e fluoruro simultaneemente, e rattos de controlo. Esseva effectuate determinationes de calcium in le sero e le urina e del gravitate specific e del contento de cinere in le femure si ben como su contento de calcium. Le resultatos revelava que fluoruro age contra le syndrome de hypervitaminosis D per reducer usque ad valores quasi normal le concentrationes de calcium in le sero e le urina e etiam que illo preveni le resorption de osso. Es suggestionate que in hypervitaminosis D, le presentia de un augmentate concentration de iones de fluoruro in le liquidos del tissus induce un precipitation de fluoro-apatite. </jats:p