Objectives: To determine Coll2-1, Coll2-1NO2 and myeloperoxydase (MPO) levels in serum of patients with knee or hip osteoarthritis (OA) before the surgery, three months and one year after knee or hip replacement.
Methods: Coll2-1, Coll2-1NO2 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, three months and one year after hip or knee replacement. Coll2-1 and Coll2-1NO2 immunohistochemistry was performed on biopsies removed from cartilage lesions.
Results: Immunostainings revealed the extensive presence of Coll2-1 and Coll2-1NO2 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. In contrast, Coll2-1NO2 levels remained elevated. At one year follow-up, Coll2-1 levels remained to the reference value, MPO levels were similar to those measured at 3 months, and Coll2-1NO2 levels were unchanged and comparable to the pre-surgery values. However, in patients with presurgery values above the median (more than 0.42 nM), Coll2-1NO2 levels significantly and progressively decreased postoperatively, but tended towards an increase in patients with presurgery Coll2-1NO2 values below the median.
Conclusions: The normalization of Coll2-1 levels three months after surgery indicates that Coll2-1 is a disease-specific marker which 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 neutrophils activation occurs in OA joint, even in the late stage of the disease.
- biological markers
- type II collagen