Osteogenic, anti-osteoclastogenic and immunomodulatory properties of a strontium-releasing hybrid scaffold for bone repair.

Strontium (Sr) is known to stimulate osteogenesis, while inhibiting osteoclastogenesis, thus encouraging research on its application as a therapeutic agent for bone repair/regeneration. It has been suggested that it may possess immunomodulatory properties, which might act synergistically in bone repair/regeneration processes. To further explore this hypothesis we have designed a Sr-hybrid system composed of an in situ forming Sr-crosslinked RGD-alginate hydrogel reinforced with Sr-doped hydroxyapatite (HAp) microspheres and studied its in vitro osteoinductive behaviour and in vivo inflammatory response.

Sensory neurons and osteoblasts: close partners in a microfluidic platform.

Innervation has proven to be critical in bone homeostasis/regeneration due to the effect of soluble factors, produced by nerve fibers, associated with changes in the activity of bone cells. Thus, in this study, we have established and characterized a coculture system comprising sensory neurons and osteoblasts to mimic the in vivo scenario where nerve fibers can be found in a bone microenvironment. Embryonic or adult primary dorsal root ganglion (DRG) and MC3T3-E1 osteoblastic cells were cocultured in compartmentalized microfluidic platforms and morphological and functional tests were performed.

A multicompartment holder for spinner flasks improves expansion and osteogenic differentiation of mesenchymal stem cells in three-dimensional scaffolds.

In the tissue engineering field dynamic culture systems, such as spinner flasks, are widely used due to their ability to improve mass transfer in suspension cell cultures. However, this culture system is often unsuitable to culture cells in three-dimensional (3D) scaffolds. To address this drawback, we designed a multicompartment holder for 3D cell culture, easily adaptable to spinner flasks.

Effect of cell density on mesenchymal stem cells aggregation in RGD-alginate 3D matrices under osteoinductive conditions.

Cellular activities in 3D are differentially affected by several matrix-intrinsic and extrinsic factors. This study highlights the relevance of optimizing initial cell densities when establishing 3D cultures for specific applications. Independently of the entrapping density, MSCs cultured within RGD-alginate hydrogels showed steady-state levels of metabolic activity and were in a nearly non-proliferative state, but recovered "normal" activity levels when retrieved from 3D matrices and re-cultured as monolayers.