Jean-Pierre Pelletier

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Osteoarthritis (OA) is associated with cartilage destruction, subchondral bone remodeling and inflammation of the synovial membrane, although the etiology and pathogenesis underlying this debilitating disease are poorly understood. Secreted inflammatory molecules, such as proinflammatory cytokines, are among the critical mediators of the disturbed processes(More)
IL-17 is a newly described, T cell-derived cytokine with ill-defined physiologic properties. As such, we examined the release of proinflammatory mediators by human macrophages in response to recombinant human (rh) IL-17. IL-1beta and TNF-alpha expression and synthesis were up-regulated by rhIL-17 in a dose (ED50 was 50 +/- 9 ng/ml)- and time-dependent(More)
Morphological changes observed in OA include cartilage erosion as well as a variable degree of synovial inflammation. Current research attributes these changes to a complex network of biochemical factors, including proteolytic enzymes, that lead to a breakdown of the cartilage macromolecules. Cytokines such as IL-1 and TNF-alpha produced by activated(More)
The preservation of articular cartilage depends on keeping the cartilage architecture intact. Cartilage strength and function depend on both the properties of the tissue and on their structural parameters. The main structural macromolecules are collagen and proteoglycans (aggrecan). During life, cartilage matrix turnover is mediated by a multitude of(More)
BACKGROUND The relation between knee meniscal structural damage and cartilage degradation is plausible but not yet clearly proven. OBJECTIVES To quantitate the cartilage volume changes in knee osteoarthritis using magnetic resonance imaging (MRI), and determine whether meniscal alteration predicts cartilage volume loss over time. METHODS 32 patients(More)
OBJECTIVE Osteoarthritis (OA) is accompanied by subchondral bone sclerosis. The present study was undertaken to determine whether osteoblast-like cells in patients with OA show an abnormal phenotype that could contribute to this sclerosis. METHODS Explants and primary in vitro osteoblast-like cell cultures were prepared from subchondral bone specimens(More)
OBJECTIVE To determine the capacity of human subchondral osteoarthritic osteoblasts (Ob) to produce interleukin (IL)-1beta, IL-6, transforming growth factor-beta (TGF-beta) and prostaglandin E(2) (PGE(2)), and determine if a relationship exists between IL-1beta, TGF-beta, PGE(2) and IL-6 production. METHODS We measured the abundance of IL-1beta, IL-6,(More)
BACKGROUND MMP-13 and IGFBP-5 are important factors involved in osteoarthritis (OA). We investigated whether two highly predicted microRNAs (miRNAs), miR-140 and miR-27a, regulate these two genes in human OA chondrocytes. METHODS Gene expression was determined by real-time PCR. The effect of each miRNA on IGFBP-5 and MMP-13 expression/production was(More)
OBJECTIVE To evaluate the in vivo therapeutic efficacy of N-iminoethyl-L-lysine (L-NIL), a selective inhibitor of inducible nitric oxide synthase (iNOS), on the progression of lesions in an experimental osteoarthritis (OA) dog model. The effect of L-NIL on metalloprotease activity, levels of interleukin-1beta (IL-1beta), prostaglandin E2 (PGE2), and(More)
Osteoarthritis (OA) is a well-known disease that is part of the aging process and also one of the most common diseases among mammals. Although this musculoskeletal disorder has been described in mammals of many ages, having been reported in Egyptian mummies and in dinosaurs, its exact etiology is far from being fully understood. With the graying of the(More)