Macromechanics and polycaprolactone fiber organization drive macrophage polarization and regulate inflammatory activation of tendon in vitro and in vivo.

Appropriate macrophage response to an implanted biomaterial is crucial for successful tissue healing outcomes. In this work we investigated how intrinsic topological cues from electrospun biomaterials and extrinsic mechanical loads cooperate to guide macrophage activation and macrophage-tendon fibroblast cross-talk. We performed a series of in vitro and in vivo experiments using aligned or randomly oriented polycaprolactone nanofiber substrates in both mechanically loaded and unloaded conditions.

The relationship between metastatic potential and in vitro mechanical properties of osteosarcoma cells.

Osteosarcoma is the most frequent primary tumor of bone and is characterized by its high tendency to metastasize in lungs. Although treatment in cases of early diagnosis results in a 5-yr survival rate of nearly 60%, the prognosis for patients with secondary lesions at diagnosis is poor, and their 5-yr survival rate remains below 30%. In the present work, we have used a number of analytical methods to investigate the impact of increased metastatic potential on the biophysical properties and force generation of osteosarcoma cells.

Substrate fiber alignment mediates tendon cell response to inflammatory signaling.

Unlabelled: Healthy tendon tissue features a highly aligned extracellular matrix that becomes disorganized with disease. Recent evidence suggests that inflammation coexists with early degenerative changes in tendon, and that crosstalk between immune-cells and tendon fibroblasts (TFs) can contribute to poor tissue healing. We hypothesized that a disorganized tissue architecture may predispose tendon cells to degenerative extracellular matrix remodeling pathways, particularly within a pro-inflammatory niche.

Macrophage Polarization by Titanium Dioxide (TiO) Particles: Size Matters.

Wear particles of total joint replacements may lead to an inflammatory response driven by cells of the monocyte/macrophage lineage. Today, there is a general agreement that the continuous release of wear particles by the implant has a critical impact on periprosthetic osteolysis, which can eventually lead to aseptic loosening of the implant. The focus of this study lay on the determination of the polarization of macrophages (M0) toward the pro-inflammatory M1 phenotype or the anti-inflammatory M2-like phenotype upon exposure to differently sized TiO particles.