Serum levels of hyaluronan, antigenic keratan sulfate, matrix metalloproteinase 3, and tissue inhibitor of metalloproteinases 1 change predictably inrheumatoid arthritis patients who have begun activity after a night of bedrest

Objective. To evaluate whether and how moderate physical activity following a night of rest influences serum levels of matrix metalloproteinase 3 (MMP -3), tissue inhibitor of metalloproteinases 1 (TIMP-1), antigenic keratan s ulfate (Ag KS), and hyaluronan (HA) in 10 normal subjects and 38 patients w ith rheumatoid arthritis (RA). Methods. Blood was obtained from 20 RA patients before they arose from a ni ght's sleep, and again 1 and 4 hours after they had begun to perform modera te physical activity. Another 18 RA patients remained in bed and blood was sampled at the same time periods. Serum levels of MMP-3, TIMP-1, Ag KS, and HA were measured by enzyme-linked immunosorbent assay. Clinical activity w as evaluated by the Lansbury index. Results. Both in normal subjects and in RA patients who did not remain in b ed throughout the period of blood sampling, levels of HA, Ag KS, and MMP3 i ncreased significantly during the first hour after the subjects arose: the increase in HA and Ag KS correlated with the Lansbury index in the RA group . Three hours later, levels of Ag KS had dropped to baseline values in both groups of subjects. Levels of HA remained significantly and moderately ele vated in the RA group but not in the control group, while levels of MMP-3 d id not drop significantly in either group. In contrast, levels of HA, Ag KS , and MMP3 did not change significantly in RA patients who had remained in bed. Unlike the other markers, the levels of TIMP-1 remained unchanged at t he different time periods in all 3 groups studied. Conclusion. Significant changes in serum levels of some metabolic markers o ccur during the first hour after one arises from a night of sleep, especial ly in patients with RA. Measurement of the magnitude of these changes at di fferent times in individual patients provides very different information ab out metabolic changes occurring in joint tissue than does measurement of th e level of the markers at a single time point, as is usually currently repo rted.