Expression Pattern of iNOS, BCL-2 and MMP-9 in the Hip Synovium Tissue of Patients with Osteoarthritis
Davor Caric1, Sandra Zekic Tomas2, Natalija Filipovic3
1Department of Orthopaedics and Traumatology, University Hospital in Split, Spinciceva 1, 21000 Split, Croatia.
Insights
Synovial inflammation in hip osteoarthritis (HOA) involves iNOS, BCL-2, and MMP-9. These markers correlate with disease severity, impacting cartilage health and guiding treatment decisions for hip replacement.
Area of Science:
- Orthopedics
- Pathology
- Immunology
Background:
- Hip osteoarthritis (HOA) involves cartilage degradation and synovitis, but the precise role of synovial inflammation is unclear.
- Understanding synovial tissue's pathohistological effects is crucial for managing HOA progression.
Purpose of the Study:
- To evaluate the expression of inducible nitric oxide synthase (iNOS), BCL-2, and matrix metalloproteinase-9 (MMP-9) in synovial cell populations.
- To correlate these molecular markers with clinical and histopathological grading of hip osteoarthritis.
Main Methods:
- Retrospective analysis of 32 hip osteoarthritis patients undergoing total hip arthroplasty.
- Immunohistochemical analysis of synovial tissues for iNOS, BCL-2, and MMP-9 expression.
- Assessment of clinical severity using Kellgren-Lawrence (K-L) grade, Krenn score, Harris Hip Score (HHS), and OARSI.
Main Results:
- Synovial cell layer, resident cells, and inflammatory infiltration increased with HOA severity (K-L grade, Krenn score).
- iNOS expression positively correlated with Krenn score in moderate and severe HOA.
- BCL-2 expression in the intima of severe HOA patients also correlated positively with the Krenn score.
Conclusions:
- iNOS, BCL-2, and MMP-9 are implicated in the pathobiology of hip osteoarthritis.
- A significant relationship exists between synovial inflammation, histopathological features, and cartilage status in patients with hip osteoarthritis requiring surgery.
Abstract:
Hip osteoarthritis (HOA) is characterized by degradation of the cartilage and synovitis. However, the pathohistological effects of synovial tissue inflammation on HOA are not clear. The aim of this study was to evaluate the expression of iNOS, BCL-2 and MMP-9 markers in different synovial cell populations. A total of 32 patients were evaluated retrospectively. Age, sex, height, weight, body mass index were recorded and lymphocyte, fibrocytes and macrophages were analysed in tissue sections. Osteoarthritis cartilage histopathology assessment system (OARSI), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Krenn score, Harris Hip Score (HHS) and Kellgren-Lawrence (K-L) grading of the hip joints were performed. Total hip arthroplasty was performed on 32 patients and controls. Patients were divided into two groups according to their disease severity. The tissues were immunohistochemically analysed. K-L grade and Krenn score differ between all three groups, but also between moderate and severe OA. Synovial lining cell layer, resident cells in stroma and especially inflammatory infiltration were increasing with severity of OA. iNOS expression in both intima and subintima was positively correlated with Krenn score in moderate and severe osteoarthritis (OA) groups. Expression of BCL-2 in intima of severe OA patients was positively correlated with Krenn score. In conclusion, iNOS, BCL-2 and MMP-9 are involved in the regulation of HOA. Our study indicates a relationship between the pathohistological features, the synovial inflammation and the cartilage condition at the time of hip replacement due to OA or femoral neck fracture.
