Profile of synovial inflammatory mediators in patients with knee osteoarthritis following SARS-CoV-2 infection

BACKGROUND: Post-acute consequences of COVID-19 (PASC), alongside other health conditions, are becoming a worldwide concern with uncertain molecular causes. Cytokines and matrix metalloproteinases (MMPs) are crucial in regulating inflammation and immune responses and are important for normal and abnormal processes. They are also involved in developing and progressing osteoarthritis (OA). Our study aimed to analyze the levels of cytokines, proteolytic enzymes, and vascular endothelial growth factor (VEGF) in the synovial fluid (SF) samples of OA patients who have recovered from COVID-19.METHODS: The research was conducted at the Orthopedic Specialty Clinic in Ternopil, Ukraine. Patients were primarily diagnosed with early changes and moderate OA, and they were between the ages of 45 and 68. Among the patients with joint pathology, a specific group was identified consisting of individuals who had recovered from COVID-19 6-9 months ago. Using enzyme-linked immunosorbent assays, the pro-inflammatory (IL-1β, IL-6, IL-8, IL-12β, TNF-α, IFN-γ) and anti-inflammatory (IL-4, IL-10) cytokine levels, as well as VEGF and matrix metalloproteinases MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, and MMP-10, were measured in SF samples.RESULTS: A rise in synovial IL-6 levels was observed alongside a decrease in IL-4, IL-8, and TNF-α levels in patients with OA following SARS-CoV-2 infection, compared to OA patients without COVID-19. There was no significant difference in synovial VEGF levels between OA patients who had recovered from COVID-19 and those without Coronavirus-related conditions. Post-COVID-19, decreased levels of MMP-1 and MMP-8 were observed in synovial fluid from OA patients.CONCLUSIONS: The findings reveal that even though it has been a while since the acute SARS-CoV-2 infection and the immune-related symptoms of the viral disease have lessened, there were still detectable changes in the cytokine profile and proteolysis systems in the synovial fluid of patients with OA. These changes may suggest persistent or lingering inflammation in the joints following COVID-19.