In contrast to matrix metalloproteinases, serum adiponectin concentrations increase after radioiodine treatment of thyrotoxicosis.

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, and anti-inflammatory adiponectin are altered by pharmacological treatment of acute thyrotoxicosis or by radioiodine therapy (RIT).

MATERIAL AND

METHODS

We measured serum concentrations of MMP-2, MMP-9, TIMP-1, TIMP-2, and adiponectin, TSH, free T4 (FT4) and free T3 (FT3) in 15 patients (4 males), age (years) 51.8±15.3 (mean±SD) with hyperthyroidism treated with thiamazole (Group 1) and in 20 subjects (2 males), treated for thyrotoxicosis with radioiodine, age 52.3±12.4 (Group 2), where blood samples were taken before RIT, visit 1 (V1), seven days post RIT, visit 2 (V2), and two to three months post RIT, visit 3 (V3).

RESULTS

In Group 1 there was no significant change in concentrations of MMP-2, MMP-9, TIMP-1, TIMP-2 or adiponectin, despite a fall in FT4 and FT3 (8.74±4.79 pg/ml vs 3.54±2.40 pg/ml, for FT3, and 4.48 ±2.21 ng/ml vs 1.02±1.07 ng/ml, for FT4, p<0.001). In Group 2 RIT did not cause any acute change in serum MMP-2, MMP-9, TIMP-1 and TIMP-2 or adiponectin (V1 vs V2). 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 V3 [from 129±45 ng/ml (V1) to 149±38 ng/ml (V3), p<0.01]. There was no significant change MMP-2, MMP-9 and TIMP-1 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.

CONCLUSIONS

Radioiodine therapy of thyrotoxicosis does not alter serum MMP-2, MMP-9 or TIMP-1 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.