Basic science of osteoarthritis

Osteoarthritis (OA) is a prevalent, disabling disorder of the joints that affects a large population worldwide and for which there is no definitive cure. This review provides critical insights into the basic knowledge on OA that may lead to innovative end efficient new therapeutic regimens. While degradation of the articular cartilage is the hallmark of OA, with altered interactions between chondrocytes and compounds of the extracellular matrix, the subchondral bone has been also described as a key component of the disease, involving specific pathomechanisms controlling its initiation and progression. The identification of such events (and thus of possible targets for therapy) has been made possible by the availability of a number of animal models that aim at reproducing the human pathology, in particular large models of high tibial osteotomy (HTO). From a therapeutic point of view, mesenchymal stem cells (MSCs) represent a promising option for the treatment of OA and may be used concomitantly with functional substitutes integrating scaffolds and drugs/growth factors in tissue engineering setups. Altogether, these advances in the fundamental and experimental knowledge on OA may allow for the generation of improved, adapted therapeutic regimens to treat human OA.(undefined

Chemotactic and immunoregulatory properties of bone cells are modulated by endotoxin-stimulated lymphocytes

In our study, we explored the bidirectional communication via soluble factors between bone cells and endotoxin-stimulated splenic lymphocytes in an in vitro coculture model that mimics the inflammatory environment. Both the ability of lymphocytes to affect differentiation and immune properties of bone cells, osteoblasts (OBL) and osteoclasts (OCL), and of bone cells to modulate cytokine and activation profile of endotoxin-stimulated lymphocytes were tested. LPS-pulsed lymphocytes enhanced OCL but inhibited OBL differentiation and increased the RANKL/OPG ratio, and, at the same time, upregulated chemotactic properties of bone cells, specifically CCL2, CCL5, and CXCL10 in OCL and CCL5 and CXCL13 in OBL. In parallel, bone cells had immunosuppressive effects by downregulating the lymphocyte expression of interleukin (IL)-1, IL-6, TNF-α and co-stimulatory molecules. OCL stimulated the production of osteoclastogenic cytokine RANKL in T lymphocytes. The anti-inflammatory effect, especially of OBL, suggests a possible compensatory mechanism to limit the inflammatory reaction during infection

Regime of the Filchner-Ronne Ice Shelves, Antarctica

Seismic, radio-echo, TWERLE balloon and oceanographic data of the Filchner-Ronne ice shelves are analysed. A large thin area in the central Ronne Ice Shelf is found to differ from the morphology of the Ross and Filchner ice shelves. This area is partly filled by basal saline ice, which can be attributed to regional regelation caused by oceanic circulation