Equine myeloperoxidase: a novel biomarker in synovial fluid for the diagnosis of infection.

This research investigates if identifying the presence and enzyme activity of myeloperoxidase (MPO), a potential biomarker, in the joint fluid of horses can assist in diagnosing joint infections, a potentially lethal condition. It suggests that the analysis of MPO in synovial fluid can be used to differentiate between infectious and noninfectious causes of joint diseases in horses.

Objectives and Methodology

• The researchers wanted to understand if the detection of total and enzymatically active myeloperoxidase (MPO) can aid in diagnosing joint infection in horses.
• They examined four sample groups: healthy joints, joints affected by osteochondritis dissecans (OCD), joints with traumatic synovitis, and joints with culture-confirmed infections.
• The joint fluid was tested for total MPO by a horse-specific sandwich enzyme-linked immunosorbent assay (ELISA), a technique that quantifies and detects antibodies. The fluid was tested for active MPO using the specific immunological extraction followed by enzymatic detection (SIEFED) technique.
• The antibody specificity was affirmed through Western blot analysis, a method used to detect specific proteins.

Results and Findings

• The joint fluid from infected joints contained significantly more total and active MPO than samples from healthy joints or those affected by OCD or traumatic synovitis.
• Specific cut-off values were established for total and active MPO with a reasonable level of sensitivity, specificity, and predictive rates for infection.
• Correlation coefficients were found between the total and active MPO levels and routine synovial fluid parameters like the white blood cell count, neutrophil count, and total protein level.
• No clear associations were found between MPO and the age of the horse or the specific joint affected.

Conclusions

• The researchers concluded that MPO in synovial fluid is a promising biomarker for differentiating between infectious and noninfectious joint diseases in horses.
• Both ELISA and SIEFED techniques can be effectively used for its rapid and specific detection.
• The analysis of synovial fluid MPO can supplement diagnostic tests, especially when the white blood cell counts and total protein levels don’t provide clear answers.