Temperature evolution following joint loading promotes chondrogenesis by synergistic cues via calcium signaling.

During loading of viscoelastic tissues, part of the mechanical energy is transformed into heat that can locally increase the tissue temperature, a phenomenon known as self-heating. In the framework of mechanobiology, it has been accepted that cells react and adapt to mechanical stimuli. However, the cellular effect of temperature increase as a by-product of loading has been widely neglected.

3D-Printed Reinforcement Scaffolds with Targeted Biodegradation Properties for the Tissue Engineering of Articular Cartilage.

Achieving regeneration of articular cartilage is challenging due to the low healing capacity of the tissue. Appropriate selection of cell source, hydrogel, and scaffold materials are critical to obtain good integration and long-term stability of implants in native tissues. Specifically, biomechanical stability and in vivo integration can be improved if the rate of degradation of the scaffold material matches the stiffening of the sample by extracellular matrix secretion of the encapsulated cells.

Microencapsulation improves chondrogenesis in vitro and cartilaginous matrix stability in vivo compared to bulk encapsulation.

The encapsulation of cells into microgels is attractive for applications in tissue regeneration. While cells are protected against shear stress during injection, the assembly of microgels after injection into a tissue defect also forms a macroporous scaffold that allows effective nutrient transport throughout the construct. However, in most of current strategies that form microgel-based macroporous scaffold or higher-order structures, cells are seeded during or post the assembly process and not microencapsulated in situ.

Polyelectrolyte nanocomplexes based on chitosan derivatives for wound healing application.

Wound healing, when compromised, may be guided by biological cues such as Arg-Gly-Asp (RGD), a peptide known to induce cell adhesion and migration, eventually combined with adapted nanocarriers. Three different formulations were prepared and investigated in vitro for topical application. All formulations were based on carboxylated and trimethylated chitosan (CMTMC) displaying RGD.

Human chondroprogenitors in alginate-collagen hybrid scaffolds produce stable cartilage in vivo.

The goal of this study was to evaluate human epiphyseal chondroprogenitor cells (ECPs) as a potential new cell source for cartilage regeneration. ECPs were compared to human bone marrow stromal cells (MSCs) and human adult articular chondrocytes (ACs) for their chondrogenic potential and phenotypic stability in vitro and in vivo. The cells were seeded in Optimaix-3D scaffolds at 5 × 10 cells/mm and gene expression, matrix production and mechanical properties were analysed up to 6 weeks.

Osteogenesis imperfecta: from diagnosis and multidisciplinary treatment to future perspectives.

Osteogenesis imperfecta is an inherited connective tissue disorder with wide phenotypic and molecular heterogeneity. A common issue associated with the molecular abnormality is a disturbance in bone matrix synthesis and homeostasis inducing bone fragility. In very early life, this can lead to multiple fractures and progressive bone deformities, including long bone bowing and scoliosis.

Repair of critical size defects in the rat cranium using ceramic-reinforced PLA scaffolds obtained by supercritical gas foaming.

Bioresorbable scaffolds made of poly(L-lactic acid) (PLA) obtained by supercritical gas foaming were recently described as suitable for tissue engineering, portraying biocompatibility with primary osteoblasts in vitro and interesting mechanical properties when reinforced with ceramics. The behavior of such constructs remained to be evaluated in vivo and therefore the present study was undertaken to compare different PLA/ceramic composite scaffolds obtained by supercritical gas foaming in a critical size defect craniotomy model in Sprague-Dawley rats. The host-tissue reaction to the implants was evaluated semiquantitatively and similar tendencies were noted for all graft substitutes: initially highly reactive but decreasing with time implanted.

Biocompatibility of bioresorbable poly(L-lactic acid) composite scaffolds obtained by supercritical gas foaming with human fetal bone cells.

The aim of this investigation was to test the biocompatibility of three-dimensional bioresorbable foams made of poly(L-lactic acid) (PLA), alone or filled with hydroxyapatite (HA) or beta-tricalcium phosphate (beta-TCP), with human primary osteoblasts, using a direct contact method. Porous constructs were processed by supercritical gas foaming, after a melt-extrusion of ceramic/polymer mixture. Three neat polymer foams, with pore sizes of 170, 310, and 600 microm, and two composite foams, PLA/5 wt% HA and PLA/5 wt% beta-TCP, were examined over a 4-week culture period.