A paper involving the FRAME Alternatives Laboratory has been accepted for publication in the journal Osteoarthritis and Cartilage.
The project involved a collaboration with the Arthritis Research UK Pain Centre and other departments within the University of Nottingham and Sherwood Forest Hospitals NHS Foundation Trust.
Knee pain associated with symptomatic osteoarthritis occurs not only in patients with severe knee damage, but also in cases where little damage is observed. Although the mechanisms for causing osteoarthritic knee pain are poorly understood, a contributing factor can be synovial pathology. Here, knee pain is thought to be caused by the presence of certain molecules associated with inflammation in the synovium. The presence of specific molecules may lead to the sensitisation of nerves, causing painful stimuli.
This study looked at the expression of proteins within the synovial membrane of the knee to identify which inflammatory markers can be seen with symptomatic, but not asymptomatic, osteoarthritis. If the inflammatory markers associated with causing pain can be identified, this could help inform current therapies and the development of new treatments.
The expression of 96 genes involved in inflammation and nerve sensitisation were studied in samples from knees with symptomatic and asymptomatic osteoarthritis. Eight genes were found to be differently expressed between cases where there was severe knee pain and cases where there was not. Of these genes, three associated proteins were seen in increased levels in the synovium of the symptomatic cases. Further research into the potential role of these molecules in causing pain will give a greater understanding into the cause of symptomatic osteoarthritis in the knee.
This research provides another example of how using human patients and tissue can help to increase our understanding of the mechanisms of human disease better than an animal model. Inducing osteoarthritis in an animal or using genetically altered mice would not have provided the same insight into the role of the synovium in osteoarthritis of the knee.