[Physiopathology of osteoarthritis. From normal cartilage to osteoarthritic cartilage: risk factors and inflammatory mechanisms].
BACKGROUND
osteoarthritis is the most prevalent form of arthritis in the world. With the progressive ageing of the population, it becomes a major problem of public health. Osteoarthritis is a degenerative affection characterized by many disorders leading to a structural and functional defect of one or several joints.


BACKGROUND
In this review, we focus on the main inflammatory mechanisms occurring in cartilage during primary osteoarthritis. We also describe some well established risk factors involved in the pathogenesis of this disease such as age, overload and genetic factors. Indeed, osteoarthritis is the result of an imbalance between the processes of degradation and the attempts of repair by the chondrocyte which is the exclusive cell type in cartilage. Degradation is induced by several chemical substances such as proteolytic enzymes (metalloproteinases) and pro-inflammatory cytokines especially interleukin 1beta. To face these events, the chondrocyte starts attempts of repair by secreting growth factors (Transforming Growth Factor and Insulin Growth Factor) or anti-inflammatory cytokines (interleukins 4 and 10) unsuccessfully. All these events will lead to the structural modifications observed in the osteoarthritic cartilage.


CONCLUSIONS
A better comprehension of the physiopathology of osteoarthritis will allow an improvement of therapeutic strategies of this common and invalidating disease.
Laadhar
L
L
Laboratoire d'immunologie, hôpital La Rabta, 1007 Tunis, Tunisie. lilia_laadhar@yahoo.com
Zitouni
M
M
Kalle-Sellami
M
M
Mahjoub
M
M
Sellami
S
S
Makni
S
S
D002358:Cartilage, Articular / Q000503:physiopathology*; D006801:Humans; D007249:Inflammation / Q000503:physiopathology*; D010003:Osteoarthritis / Q000503:physiopathology*; D012307:Risk Factors