Background
In order to assess safety of radioactive iodine administration in the treatment of thyrotoxicosis, we measured concentrations of matrix metalloproteinase-2 (MMP-2), its main inhibitor - TIMP-2 (tissue inhibitor of MMP-2), matrix metalloproteinase-9 (MMP-9), its main inhibitor - TIMP-1, adiponectin, as well as pro-inflammatory and procancerogenic thrombospondin-1 (TSP-1). Design and patients: The study involved 23 patients treated with radioiodine for thyrotoxicosis. Serum concentrations of TSH, free T4, free T3, MMP-2, MMP-9, TIMP-1, TIMP-2, total adiponectin and TSP-1 were measured by immunoassays just before radioiodine administration (visit 1), and subsequently, after 7 days (visit 2), 3 months (visit 3), 6 to 8 months (visit 4) and 15-18 months after radioiodine administration (visit 5).
Conclusions
Our data reveal a significant and sustained increase in serum adiponectin, as well as possible decrease of free MMP-9 concentration after radioiodine administration. In contrast, there was no significant change of TSP-1. This might indicate overall safety of radioiodine treatment of thyrotoxicosis in terms of the risks of subsequent cardiovascular and neoplastic disease.
Results
There were no acute changes in serum concentrations of MMP-2, MMP-9, TIMP-1, TIMP-2, adiponectin and TSP-1 (visit 1 vs. 2). Subsequently, there was an increase in MMP-2 (from 393±106 ng/ml to 774±424 ng/ml), TIMP-1 (from 177±76 ng/ml to 296±118 ng/ml), and adiponectin (from 16442±9490 ng/ml to 23518±9840 ng/ml), visit 1 to 5, respectively (p < 0.01). Further analysis revealed no significant change in MMP-2/TIMP-2 ratio, but there was a significant decrease in MMP-9/TIMP-1 ratio (p < 0.05), suggestive of possible decrease in free MMP-9 concentrations. Conclusions: Our data reveal a significant and sustained increase in serum adiponectin, as well as possible decrease of free MMP-9 concentration after radioiodine administration. In contrast, there was no significant change of TSP-1. This might indicate overall safety of radioiodine treatment of thyrotoxicosis in terms of the risks of subsequent cardiovascular and neoplastic disease.