Notch signaling is involved in human articular chondrocytes de-differentiation during osteoarthritis.

CONTEXT: During osteoarthritis (OA), chondrocytes undergo de-differentiation, resulting in the acquisition of a fibroblast-like morphology, decreased expression of collagen type II (colII) and aggrecan, and increased expression of collagen type I (colI), metalloproteinase 13 (MMP13) and nitric oxide synthase (eNOS). Notch signaling plays a crucial role during embryogenesis. Several studies showed that Notch is expressed in adulthood. OBJECTIVE: The aim of our study was to confirm the involvement of Notch signaling in human OA at in vitro and ex vivo levels. MATERIALS AND METHODS: Normal human articular chondrocytes were cultured during four passages either treated or not with a Notch inhibitor: DAPT. Human OA cartilage was cultured with DAPT for five days. Chondrocytes secreted markers and some Notch pathway components were analyzed using Western blotting and qPCR. RESULTS: Passaging chondrocytes induced a decrease in the cartilage markers: colII and aggrecan. DAPT-treated chondrocytes and OA cartilage showed a significant increase in healthy cartilage markers. De-differentiation markers, colI, MMP13 and eNOS, were significantly reduced in DAPT-treated chondrocytes and OA cartilage. Notch1 expression was proportional to colI, MMP13 and eNOS expression and inversely proportional to colII and aggrecan expression in nontreated cultured chondrocytes. Notch ligand: Jagged1 increased in chondrocytes culture. DAPT treatment resulted in reduced Jagged1 expression. Notch target gene HES1 increased during chondrocyte culture and was reduced when treated with DAPT. CONCLUSION: Targeting Notch signaling during OA might lead to the restitution of the typical chondrocyte phenotype and even to chondrocyte redifferentiation during the pathology.

Atypical form of melorheostosis improved by pamidronate.

BACKGROUND: Melorheostosis is a rare chronic bone disease of unknown etiology that often affects a single limb. AIM: Report a new case of melorheostosis of the ribs improved by pamidronate infusions CASE: A 36-year-old man without any medical history was admitted for a history of one month painful tumefaction on the 7th left rib. The diagnosis of melorheostosis of the rib and the tibia was made. Patient was treated by pamidronate infusions with useful and satisfactory outcome.

[Spiral computed tomographic (CT) arthrography versus arthroscopy in internal derangements of the knee]. / Confrontation arthroscanner helicoidal-arthroscopie dans les dérangements internes du genou.

BACKGROUND: The spiral computed tomographic (CT) arthrography of the knee represents an alternative for MRI in the diagnosis of intraarticular lesions of the knee. METHODS: We compared, in our retrospective study relates to fifty knees presenting meniscal or anterior cruciate ligament or cartilage lesions, the data of spiral computed tomographic (CT) arthrography and arthroscopy taken as "Gold Standard". The purpose was to determine the reliability of the spiral CT arthrography in the diagnosis of intraarticular derangements of the knee. RESULTS: We found that sensibility and specificity of spiral CT tomography were respectively 86% and 81% for the detection of meniscal tears. They were respectively 60% and 86% for the detection of the cartilage lesions. The sensibility and specificity were respectively 47% and 94% for the detection of anterior cruciate ligament lesion. CONCLUSION: the spiral CT arthrography, with its submillimeter spatial resolution, was reliable in the diagnosis of the meniscal and cartilage lesions whereas its value in the diagnosis of the anterior cruciate ligament tears remains to be determined.