This study investigates the adhesion, cytoskeletal changes, and resorptive activity of disaggregated rat osteoclasts cultured on polished slices of three biomaterials: crystalline synthetic hydroxyapatite (HA), carbonated hydroxyapatite (C-HA), and natural calcium carbonate (C). The surface chemistry of each substrate was defined by X-ray diffraction and IR spectroscopy, surface wettability by the dispersive, and the polar components of the surface energies. Osteoclast adhesion was modulated by the polar component of the surface energy: fewer (p < 0.01) osteoclasts adhered to C-HA (97 +/- 20/slice, surface energy 9 +/- 5 mJ/m2) than to HA (234 +/- 16/slice, surface energy 44 +/- 2 mJ/m2) or to C (268 +/- 37/slice, surface energy 58 +/- 0.5 mJ/m2). Actin rings, which are the cytoskeletal structure essential for resorption, developed on all three materials. The area of the actin ring, which is resorbed by local acidification, and the osteoclast area, which reflects osteoclast spreading, were both greater in osteoclasts cultured on HA and C-HA than in those cultured on C. C was resorbed, but HA and C-HA were not. Thus, the surface energy plays an essential role in osteoclast adhesion, whereas osteoclast spreading may depend on the surface chemistry, especially on protein adsorption and/or on newly formed apatite layers. Resorption may be limited to the solubility of the biomaterial.
Head and neck squamous cell carcinoma (HNSCC) comprise a wide spectrum of neoplasms with different tumor biologies, prognosis and response to therapies. Current tumor classification and traditional diagnostic methods (e.g. clinical assessment, histopathology) are limited in their capacity to determine prognosis and clinical decision-making. Despite recent improvements in treatment, the outcome for patients with HNSCC remains poor. Similar to most tumors, several patient-related factors, (e.g. genetics and environment) and disease-related factors (e.g. tumor location, TMN staging) play a significant role on survival. Thus, the problem in defining the prognosis is that the clinical course and response to treatment differ considerably among patients. Such interindividual variability is related to the heterogeneity of the tumor, genetic and epigenetic variations, thus reflecting the interaction of multiple biological components that result in a unique phenotype. Integrative genomics are developed to identify the molecular pathways leading to cancer at the individual level and find novel prognostic markers for HNSCC, hence tailoring a treatment accordingly. Such genetic-based personalized diagnosis allows tumor stratification and implementation of targeted therapy. Modern medicine includes new drugs that disrupt the implicated molecules and their signaling pathways. Here, we summarize the current state of knowledge that elucidates the translation of genetic data into clinical benefit.
Bone regeneration is an indispensable procedure for implant placement. Original techniques based on mesenchymal stromal cell (MSC) therapy are emerging with the goal of speeding up biology, thereby reducing the osseointegration period. Many products found their way in clinical application, yet their reliability remains uncertain because many in vitro culture-related challenges are facing these cells once they are out of their biologic environment. In this commentary, these limitations are discussed with the emphasis of their impact on the performance of MSCs. Clinicians should be aware of these issues before implementing this cell-based regenerative technique.
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