ABSTRACT
OBJECTIVES: To determine Coll2-1, Coll2-1NO(2) and myeloperoxydase (MPO) levels in serum of patients with knee or hip osteoarthritis (OA) before the surgery, 3 months and 1 year after knee or hip replacement. METHODS: Coll2-1, Coll2-1NO(2) and MPO were measured in 103 patients with isolated symptomatic knee or hip OA candidates for joint replacement. Sera were taken the day before surgery, 3 months and 1 year after hip or knee replacement. Coll2-1 and Coll2-1NO(2) immunohistochemistry was performed on biopsies removed from cartilage lesions. RESULTS: Immunostainings revealed the extensive presence of Coll2-1 and Coll2-1NO(2) in the superficial layer of fibrillated cartilage and around some chondrocytes clusters. Three months after joint replacement, Coll2-1 and MPO serum levels were decreased and even reached the reference value for Coll2-1. By contrast, Coll2-1NO(2) levels remained elevated. At 1-year follow-up, Coll2-1 levels remained at the reference value, MPO levels were similar to those measured at 3 months, and Coll2-1NO(2) levels were unchanged and comparable to the pre-surgery values. However, in patients with pre-surgery values above the median (more than 0.42 nM), Coll2-1NO(2) levels significantly and progressively decreased post-operatively, but tended towards an increase in patients with pre-surgery Coll2-1NO(2) values below the median. CONCLUSIONS: The normalisation of Coll2-1 levels 3 months after surgery indicates that Coll2-1 is a disease-specific marker that is sensitive to the structural changes occurring in a single joint. Furthermore, the immunohistochemical findings are consistent with the concept that the major source of serum Coll2-1 is the damaged articular cartilage. Finally, serum MPO levels decreased after joint replacement indicating that neutrophil activation occurs in OA joints, even in the late stage of the disease.
Subject(s)
Collagen Type II/metabolism , Osteoarthritis, Hip/metabolism , Osteoarthritis, Knee/metabolism , Peptide Fragments/metabolism , Peroxidase/blood , Aged , Aged, 80 and over , Arthroplasty, Replacement, Hip , Arthroplasty, Replacement, Knee , Biomarkers/blood , Biomarkers/metabolism , Cartilage, Articular/chemistry , Collagen Type II/blood , Female , Follow-Up Studies , Humans , Male , Middle Aged , Osteoarthritis, Hip/surgery , Osteoarthritis, Knee/surgery , Peptide Fragments/blood , Reference ValuesABSTRACT
This paper describes two new immunoassays for a peptide of the triple helix of type II collagen (Coll 2-1) and its nitrated form (Coll 2-1 NO(2)). In healthy subjects aged between 20 and 65 years old, Coll 2-1 and Coll 2-1 NO(2) levels in serum were in means 125.13+/-3.71 and 0.16+/-0.08 nmol/l, respectively. These levels did not significantly vary with age. However, up to 45 years of age, Coll 2-1 NO(2) levels in women were significantly higher than in men. In patients with knee osteoarthritis (OA), Coll 2-1 in serum was found to be elevated compared to healthy controls (267.45+/-26.42 nmol/l vs 126.78+/-6.61 nmol/l). Further, we have demonstrated that an increase of the urinary levels of Coll 2-1 or Coll 2-1 NO(2) over 1 year was predictive of joint space narrowing progression in OA patients. In conclusion, these preliminary results indicate that Coll 2-1 could be a predictive marker of knee OA progression.
