Endocrine Abstracts

Background: Matrix metalloproteinases (MMPs), together with their tissue inhibitors (TIMPs), remodel extracellular matrix under physiological and pathological conditions and are implicated in pathogenesis of cardiovascular diseases, cancer and in chronic inflammation. We have endeavoured to assess whether concentrations of MMPs, TIMPs, proinflammtory thrombospondin and anti-inflammatory adiponectin are altered by administration of radioiodine during treatment of thyrotoxicosis.

Material & Methods: We measured serum concentrations of MMP-2, MMP-9, TIMP-1, TIMP-2, thrombospondin and adiponectin as well as lipids, TSH, fT4, and fT3 before radioiodine administration (RIA), visit 1 (V1), seven days post RIA, visit 2 (V2), and two-three months post RIA, visit 3 (V3) in 20 subjects (2 males), treated for thyrotoxicosis (age (mean±SD) 52.3±12.4 years).

Results: RIA did not cause any acute change in serum MMP-2, MMP-9, TIMP-1 and TIMP-2, thrombospondin or adiponectin (V1 versus V2). Subsequently, however, there was a significant increase in serum adiponectin (from 15201±8860 ng/mL(V1) to 19373±8657 ng/mL (at V3), P<0.05), and TIMP-2 at visit 3 (from 129±45 ng/mL (V1) to 149±38 ng/mL (V3), P<0.01). There was no significant change MMP-2, MMP-9, TIMP-1 and thrombospondin between V1 and V3. There was a decrease in fT4 and fT3 from 24.4±15.4 pmol/L (V1) to 14.7±10.6 pmol/L (V3), and from 10.0±5.65 (V1) to 6.1±4.8 pmol/L (V2), P<0.01, for fT4 and fT3, respectively. This was accompanied by an increase in total and LDL cholesterol between V1 and V3 (P<0.01), however, without significant change in HDL cholesterol (P=0.23).

Conclusions: Radioiodine treatment of thyrotoxicosis appears vey safe, as administration of radioiodine does not alter serum MMP-2, MMP-9, TIMP-1 or thrombospondin concentrations either acutely or after about three months of observation. An increase in serum adiponectin might reflect favourable effects of radioiodine administration on cardiovascular risk factors, while an increase in TIMP-2 (principal MMP-2 inhibitor) might lead to a decrease in free MMP-2 concentrations.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.