WNT signaling and chondrocytes: from cell fate determination to osteoarthritis physiopathology.

CONTEXT: Osteoarthritis (OA) is an articular disorder leading to the degradation of articular cartilage phenotypical chondrocytes modifications, including the acquisition of a fibroblast-like morphology, decreased expression of collagen type II, and increased expression of fetal collagen type I, metalloproteinase 13 and nitric oxide synthase. This promotes matrix degradation and unsuccessful cartilage repair. WNT signaling constitutes one of the most critical biological processes during cell fate assignment and homeostasis. OBJECTIVES: This review aims to give an insight on results from the studies that were interested in the involvement of WNT in OA. METHODS: Studies were selected through a pubmed search. RESULTS: Recent genetic data showed that aberration in WNT signaling may be involved in OA. WNT signals are transduced through at least three cascades: the canonical WNT/ß-catenin pathway, the WNT/Ca(2+) pathway and the WNT/planar cell polarity pathway. Most of the studies used in-vitro models to elucidate the involvement of WNT in the physiopathology of OA. These studies analyzed the expression pattern of WNT pathway components during OA such as WNT5, WNT7, co-receptor LRP, ß-catenin, WNT target genes (c-jun, cyclins) and/or the interaction of these components with the secretion of OA most important markers such as IL-1, collagens, MMPs. Results from these studies are in favor of a deep involvement of the WNT signaling in the physiopathology of OA either by having a protective or a destructive role. CONCLUSION: Deeper researches may eventually allow scientists to target WNT pathway in order to help develop efficient therapeutic approaches to treat OA.

Hyperparathyroidism: Unusual location of brown tumors.

Brown tumors (BTs) are due to a proliferation of multinucleated giant cells in osteolytic lesions. They complicate the course of hyperparathyroidism. Thanks to an early screening of bone metabolism disorders; BTs are nowadays rare bone manifestations. We demonstrate through these two cases reports unusual locations of BTs in hyperparathyroidism.

Adherence to biologic disease-modifying antirheumatic drugs in adult patients with rheumatic diseases.

INTRODUCTION: The emergence of biologics has revolutionized the management of refractory rheumatic diseases (RD) by improving clinical outcomes. Unfortunately, the impact of non-adherence to the emerging therapy can limit their potential benefit. The objective of our study was to evaluate biologics' adherence in Tunisian patients with RD and to assess the determinants of non-adherence. METHODS: We conducted a cross-sectional study involving patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA) treated with bDMARDs (biologic disease-modifying antirheumatic drugs) for at least three months. Socio-demographic, clinical and biological data were collected. Biologic adherence was assessed using the compliance questionnaire for rheumatology (CQR). RESULTS: One hundred patients with RD (45 RA and 55 SpA) were collected. Non-adherence to bDMARDs was found in 70% of cases. In univariate analysis, non-adherence to bDMARDs was statistically related to the absence of coxitis (P=0.003), to a low ASDAS-CRP (ankylosing spondylitis disease activity score) prior to the initiation of the bDMARDs (P=0.01), to a rate of administration of bDMARDs less than one injection per month (P=0.01), to the subcutaneous delivery route (P=0.02) as well as to non-adherence to csDMARDs (conventional disease-modifying antirheumatic drugs) (P=0.001). In multivariate analysis, the predictors of non-adherence were the absence of coxitis (OR=6.01; IC 95% [1.88-19.12]; P=0.002], and a rate of administration of bDMARDs less than one injection per month (OR=8.79; IC 95% [2.13-36.22]; P=0.003). CONCLUSION: This work has revealed the low rate of adherence to biological treatments in Tunisian patient with RD. Predictors of poor adherence were the absence of coxitis and a rate of administration of bDMARDs less than one injection per month. Detection of these factors could help us to adapt our strategies to improve adherence that are essentially based on therapeutic education program.