Higher levels of physical exercise were associated with significantly longer T1-relaxation times in knee cartilage (382 ms in nonexercisers vs 424 ms in moderate exercisers vs 476 ms in elite runners).
Cross-Sectional (n=37)
Does physical exercise increase glycosaminoglycan content in human knee cartilage as measured by dGEMRIC?
Human knee cartilage adapts to physical exercise by increasing glycosaminoglycan content, as indicated by higher T1 relaxation times on dGEMRIC.
Absolute Event Rate: 476% vs 382%
p-value: p=0.0004 (Group 1 vs 2); 0.0002 (Group 2 vs 3)
Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is a new imaging technique to estimate joint cartilage glycosaminoglycan content by T1-relaxation time measurements after penetration of the hydrophilic contrast agent Gd-DTPA(2-). This study compares dGEMRIC in age-matched healthy volunteers with different levels of physical activity: Group 1 (n = 12): nonexercising individuals; Group 2 (n = 16): individuals with physical exercise averaging twice weekly; Group 3 (n = 9): male elite runners. dGEMRIC was performed 2 hr after an intravenous injection of Gd-DTPA(2-) at 0.3 mmol/kg body weight. T1 differed significantly between the three different levels of physical exercise. T1 values (mean of medial and lateral femoral cartilage) for Groups 1, 2, and 3 were: 382 +/- 33, 424 +/- 22 and 476 +/- 36, respectively (ms, mean +/- SD) (P = 0.0004, 1 vs. 2 and 0.0002, 2 vs. 3). Irrespective of the exercise level, T1 was longer in lateral compared to medial femoral cartilage (P = 0.00005; n = 37). In conclusion, this cross-sectional study indicates that human knee cartilage adapts to exercise by increasing the glycosaminoglycan content. Furthermore, results suggest a compartmental difference within the knee with a higher glycosaminoglycan content in lateral compared to medial femoral cartilage. A higher proportion of extracellular water, i.e., larger distribution volume, may to some extent explain the high T1 in the elite runners.
Tiderius et al. (Mon,) conducted a cross-sectional in healthy volunteers (n=37). Physical exercise vs. Nonexercising individuals was evaluated on T1-relaxation time (mean of medial and lateral femoral cartilage) (p=0.0004 (Group 1 vs 2); 0.0002 (Group 2 vs 3)). Higher levels of physical exercise were associated with significantly longer T1-relaxation times in knee cartilage (382 ms in nonexercisers vs 424 ms in moderate exercisers vs 476 ms in elite runners).
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