For the first time, we show that MSC number initially decline in synovial fluid (SF) upon KJD (figure 1A-B).
MSCs present in the SF showed changes in their gene expression profile upon KJD, most clearly observed during the treatment (3 weeks; figure 1C).
GDF5 and Grem1 presented with a statistically significant increased expression (p<0.05) during treatment while FAB4 expression was decreased. ACAN, PTH1R, and DDR expression had the tendency to increase over time. ADAMTS4, SOX9 and PTHLH expression showed a trend to decrease over time.
This explorative study provides for the first-time data on changes in SF MSC number and their gene expression profiles upon knee joint distraction. As such, first clues are provided for the involvement of MSCs in the regenerative process induced by joint distraction for end-stage knee OA.
The fall in SF MSCs number during distraction suggests adhesion to the arthritic surfaces in the KJD environment. Further studies are necessary to unravel the processes involved.