The Differential Effects of Propylthiouracil and Methimazole as Graves' Disease Treatment on Vascular Atherosclerosis Markers: A Randomized Clinical Trial

BACKGROUND

Hyperthyroidism is related to vascular atherosclerosis. Propylthiouracil (PTU) and methimazole, other than their antithyroid effects, may have different mechanisms in preventing atherogenesis in Graves' disease.

OBJECTIVE

This study aimed to investigate the effect of antithyroid drugs on markers of vascular atherosclerosis in Graves' hyperthyroidism.

METHODS

This study was a single-blind, randomized clinical trial conducted on 36 patients with Graves' disease in Cipto Mangunkusumo General Hospital, Jakarta, Indonesia, from June 2019 until July 2020. Graves' disease was diagnosed from clinical manifestation of hyperthyroidism with diffuse goiter and then confirmed by thyroid stimulation hormone (TSH), free T4 (fT4), and TSH-receptor antibody (TRAb) measurements. Participants were randomly assigned to either a PTU or a methimazole treatment group and followed up for 3 months. Markers of vascular atherosclerosis were represented by adhesion molecules [intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin], carotid artery stiffness [pulse wave velocity (PWV)], and thickness [carotid intima media thickness (cIMT)].

RESULTS

By the end of the study, 24 participants reached euthyroid condition (13 from the PTU group and 11 from the methimazole group). After 3 months of follow-up, in the PTU group, we noticed an improvement of ICAM-1 [pretreatment: 204.1 (61.3) vs. posttreatment: 141.6 (58.4) ng/ml; p = 0.001], VCAM-1 [837 (707-977) vs. 510 (402-630) ng/ml; p < 0.001] and E-selectin [32.1 (24.1-42.7) vs. 28.2 (21.6-36.8) ng/ml; p = 0.045] in the PTU group. In the methimazole group, only VCAM-1 improvement [725 (565-904) vs. 472 (367-590); p = 0.001] was observed. Meanwhile, we found no significant changes in PWV or cIMT in either group.

CONCLUSION

Antithyroid treatment in Graves' disease leads to improvement in adhesion molecules, with a lesser effect on methimazole, whereas there were no significant changes in PWV or cIMT. PTU may have a better mechanism compared with methimazole in terms of improving adhesion molecules.

Localization of indoleamine 2,3-dioxygenase and 4-hydroxynonenal in normal and pre-eclamptic placentae

This study was undertaken to compare placental levels of 2,3-Dioxygenase (IDO), a free radical scavenger, and 4-Hydroxynonenal (4-HNE), a major by-product of lipid peroxidation, in normal and pre-eclamptic pregnancies. Placentae were collected at caesarean section from women with a term, normal singleton pregnancy (37-40 weeks' gestation, n=10) and women with a term singleton pregnancy complicated by pre-eclampsia (n=10). IDO and 4-HNE localization and intensity was studied by semi-quantitative immunohistochemistry and differences between groups were analysed using the Mann-Whitney U test. Immunostaining for IDO was located primarily in endothelial cell nuclei, with a reduced level of staining in the cytoplasm, in most capillaries from all placentae examined. A significantly higher level of IDO immunostaining was observed in normal placentae compared to pre-eclamptic placentae (P=0.008). 4-HNE was located mainly in the cytoplasm of syncytiotrophoblast cells of all placentae examined. There were no significant differences in the pattern or intensity of 4-HNE immunostaining levels between normal and pre-eclamptic pregnancies (P=0.684). Our IDO results support the hypothesis of decreased anti-oxidative capability in the placenta and the possibility of an ineffective compensatory mechanism against increased oxidative stress in the fetus.