Enhanced proatherogenic inflammation after recombinant human TSH administration in patients monitored for thyroid cancer remnant

Objective To evaluate the effect of recombinant human TSH (rhTSH) on biomarkers of vascular endothelial cell and platelet activation in patients monitored for thyroid carcinoma remnant. Methods Circulating levels of soluble(s) intercellular adhesion molecule (sICAM)-1 and sE-selectin, as indices of vascular endothelial cell activation, of sP-selectin and sCD40 ligand (sCD40L), as indices of platelet activation, and of 8-iso-prostaglandin F2a (8-iso- PGF2a), as an index of lipid peroxidation, were evaluated in 20 patients (16 females, 48Æ0 ± 13Æ6 years) at baseline and after intramuscular rhTSH injection (0Æ9 mg/day on two consecutive days). Results At baseline, serum TSH values were below normal whereas free T3 and free T4 were within the normal range. After rhTSH injection, serum TSH increased significantly but free T3 and free T4 remained unchanged. Concomitantly, plasma sICAM-1 concentrations increased significantly (from 155Æ9 ± 39Æ 1 to 183Æ6 ± 38Æ1 ng/ml, P < 0Æ03), as did those of sE-selectin (from 74Æ8 ± 15Æ 4 to 91Æ 4 ± 12Æ 2 ng/ml, P < 0Æ0006), sP-selectin (from 56Æ4 ± 13Æ7 to 72Æ2 ± 14Æ9 ng/ml, P < 0Æ002), sCD40L (from 2Æ1 ± 0Æ9 to 2Æ8 ± 1Æ1 ng/ml, P < 0Æ03) and total 8-iso-PGF2a (from 238Æ5 ± 47Æ0 to 307Æ8 ± 41Æ2 pg/l, P < 0Æ0001). Changes in circulating levels of sCD40L were directly correlated with changes in levels of plasma total 8-iso-PGF2a (r ¼ 0Æ523, P < 0Æ02) and sP-selectin (r ¼ 0Æ480, P < 0Æ03). Conclusions Supraphysiological concentrations of rhTSH might exert proatherogenic effects by promoting activation of vascular endothelial cells and platelets probably through enhanced oxidative stress.