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Young healthy participants had reduction in markers of inflammation while running
Recently published results showed running not only decreased knee intra-articular ulnar pro-inflammatory cytokine concentration, but also facilitated the movement of cartilage oligomeric matrix protein from the joint space to the serum.
“When healthy young people run for 30 minutes, some molecules that are related to inflammation of the joint decrease in concentration, which is somewhat counterintuitive,” Matthew K. Seeley, PhD, of Brigham Young University, told Healio.com/Orthopedics. “The implications are that running might be good for your joint health due to reduced knee inflammation.”
Seeley and colleagues measured cytokine concentration in synovial fluid and serum samples collected from six recreational runners, with an average age of 24 years, before and after running and control sessions in a counterbalanced order. During the running session, researchers measured ground reaction forces while participants ran for 30 minutes at a self-selected speed. In the control session, participants rested in an unloaded, seated position for 30 minutes.
Results showed no changes in serum or synovial fluid cytokine concentration in the control condition. Researchers found a decrease in granulocyte-macrophage colony-stimulating factor (GM-CSF) and a trend for decreasing interleukin (IL)-15 concentration from pre- to post-run. The mean number of foot strikes during the run had a negative correlation with changes in IL-15 concentration, researchers noted.
According to results, serum cartilage oligomeric matrix protein (COMP) decreased and synovial fluid COMP increased in the control group, while serum COMP increased and synovial fluid COMP decreased in the running group. Researchers noted an inverse correlation between changes in serum COMP and synovial fluid COMP pre- to post-intervention.
However, Seeley noted the same research should be performed on a large sample of young healthy participants before similar research is performed on participants who are more likely to experience knee osteoarthritis.
“The findings are limited, and I cannot stress this enough because we had a small sample,” Seeley said. “We learned it is hard to get synovial fluid out of healthy knees and our sample was limited, as well as reducing characteristics, meaning that it was young [and] healthy. We only had one female in the sample, so you have to be careful on extrapolating the results too far.” – by Casey Tingle
Disclosure: Seeley reports no relevant financial disclosures.
Perspective
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Hyldahl and colleagues recently reported on a small group of healthy, nonarthritic recreational runners in which they measured synovial fluid in serum concentrations of several cytokine and chemokine concentrations after resting and running conditions. The measurements were taken before and after a 30-minute session of resting and a 30-minute session of running in a randomized fashion. The authors identified decreases in synovial fluid granulocyte macrophage colony-stimulating factor (GM-CSF) after exercise and a trend in decreasing concentrations of interleukin (IL)-15. Despite finding a decrease in two pro-inflammatory cytokines, the authors did not detect decreases in several of the more potent cytokines, including IL-1, IL-6 and IL-8. Each of these are known to induce the vigorous release of cartilage degrading matrix-metalloproteinases (MMPs) in cartilage and meniscus cells, as shown by Stone and colleagues and Loeser and colleagues. The small sample size likely also limited their ability to detect changes.
The authors identified an important early step in examining the chondroprotection of running. Serum COMP levels did increase; however, the significance of this early timepoint is unclear. Erhart-Hledik and colleagues identified that COMP levels immediately following activity did not correlate with cartilage thinning in OA subjects, but serum levels 3.5 hours after activity demonstrated a significant negative correlation with cartilage thickness at 5 years. In a contrasting study by Celik and colleagues, serum COMP levels demonstrated a smaller increase after a mechanical stimulus in individuals who are runners compared to cyclists or swimmers. The significance of comp levels and the potential protective effects of exercise for osteoarthritis remain a great interest, and this small pilot study provides a good foundation for future, larger investigations into the protective effects of exercise.
References:
Celik O, et al. Knee. 2013;doi:10.1016/j.knee.2012.06.001.
Erhart-Hledik JC, et al. Osteoarthritis Cartilage. 2012;doi:10.1016/j.joca.2012.07.018.
Loeser RF, et al. Arthritis Rheum. 2012;doi:10.1002/art.34453.
Stone AV, et al. Osteoarthritis Cartilage. 2014;doi:10.1016/j.joca.2013.11.002.
Stone AV, et al. Osteoarthritis Cartilage. 2015;doi:10.1016/j.joca.2015.05.020.