Mechanical stimulation and mitogen-activated protein kinase signaling independently regulate osteogenic differentiation and mineralization by calcifying vascular cells.

Ectopic calcification of vascular tissue is associated with several cardiovascular pathologies and likely involves active regulation by vascular smooth muscle cells and osteoblast-like vascular cells. This process often occurs in sites with altered mechanical environments, suggesting a role for mechanical stimuli in calcification. In this study, we investigated the effect of mechanical stimulation on the proliferation, osteogenic differentiation, calcification, and mitogen-activated protein kinase (MAPK) signaling in calcifying vascular cells (CVCs), a subpopulation of aortic smooth muscle cells putatively involved in vascular calcification.

Shape retaining injectable hydrogels for minimally invasive bulking.

Purpose: Particle migration, poor shape definition and/or rapid resorption limit the success of current urethral bulking agents. We propose that shape defining porous scaffolds that allow cell infiltration and anchoring, and may be delivered in a minimally invasive manner may provide many advantageous features.

Materials And Methods: Alginate hydrogels were prepared with varying degrees of covalent cross-linking and different pore characteristics.

Shape-defining scaffolds for minimally invasive tissue engineering.

Background: Minimally invasive surgical procedures are increasingly important in medicine, but biomaterials consistent with this delivery approach that allow one to control the structure of the material after implantation are lacking. Biomaterials with shape-memorizing properties could permit minimally invasive delivery of cell transplantation constructs and enable the formation of new tissues or structures in vivo in desired shapes and sizes.

Methods: Macroporous alginate hydrogel scaffolds were prepared in a number of predefined geometries, compressed into significantly smaller, different "temporary" forms, and introduced into immunocompromised mice by means of minimally invasive surgical delivery through a small catheter.

Cyclic strain enhances matrix mineralization by adult human mesenchymal stem cells via the extracellular signal-regulated kinase (ERK1/2) signaling pathway.

Physical stimuli play critical roles in the development, regeneration, and pathology of many mesenchymal tissues, most notably bone. While mature bone cells, such as osteoblasts and osteocytes, are clearly involved in these processes, the role of their progenitors in mechanically mediated tissue responses is unknown. In this study, we investigated the effect of cyclic substrate deformation on the proliferation and osteogenic differentiation of human mesenchymal stem cells (hMSCs).