Enzyme replacement therapy alters protein levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 in the serum of patients with MPS VI. The protein levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured in the serum of a patient with MPS VI before the initiation of treatment (0), as well as 1, 2, 3, 4, and 6 months after treatment by ELISA. Each bar represents the mean ± SED from experiments performed in duplicate and are presented as % of values of age- and sex-matched controls (n = 10)