Methimazole

Methimazole (MMI) is an inhibitor of ICAM-1 (intercellular adhesion molecule-1) gene transcription via modulating the function of STAT1 (signal transducer and activator of transcription 1) [1].
ICAM-1 (intercellular adhesion molecule-1), also named as CD54, is a member of IGSF (immunoglobulin super-family adhesion molecule) which is expressed on endothelial cells and immune system cells [2]. It is encoded by ICAM-1 gene, ICAM-1 functions via binding to LFA-1 (lymphocyte function associated molecule-1) or Mac-1. It has shown that ICAM-1 abnormally expressed in patients with autoimmune thyroid diseases. Through modulating the function of STAT1 (signal transducer and activator of transcription 1), methimazole could inhibit the transcription of ICAM-1[1].
Methimazole is an inhibitor of ICAM-1 expression while H2O2 and IFN-γ both could heavily enhance the expression of ICAM-1. When tested with the modified FRTL-5 rat thyroid cells, using 500 μM methimazole pretreated the cells could inhibit the induction of ICAM-1 RNA by H2O2 and IFN-γ [1].
In tadpoles with methimazole treatment, the gene expression of thyroid hormone response was increased [3]. Through administering rats with methimazole, the CH (congenital hypothyroidism) offspring could be obtained for further research [4]. In the study, Sprague Dawley rats could be made as hypothyroid model for further research via giving 0.025% methimazole [5]. Using pregnant C57Bl/6 mice model, it was shown that methimazole could be used for mice or rat without causing gross external malformations [6].
References:
1.Kim, H., et al., Methimazole as an antioxidant and immunomodulator in thyroid cells: mechanisms involving interferon-gamma signaling and H(2)O(2) scavenging. Mol Pharmacol, 2001. 60(5): p. 972-80.
2.Kojima, R., M. Kawachi, and M. Ito, Butein suppresses ICAM-1 expression through the inhibition of IkappaBalpha and c-Jun phosphorylation in TNF-alpha- and PMA-treated HUVEC. Int Immunopharmacol, 2014. 19(14): p. 00484-6.
3.Choi, J., et al., Unliganded thyroid hormone receptor alpha regulates developmental timing via gene repression as revealed by gene disruption in Xenopus tropicalis. Endocrinology, 2014. 2.
4.O'Hare, E., et al., Effects of thyroxine treatment on histology and behavior using the methimazole model of congenital hypothyroidism in the rat. Neuroscience, 2014. 20: p. 128-138.
5.Herwig, A., et al., A thyroid hormone challenge in hypothyroid rats identifies t3 regulated genes in the hypothalamus and in models with altered energy balance and glucose homeostasis. Thyroid, 2014. 24(11): p. 1575-93.
6.Mallela, M.K., et al., Evaluation of developmental toxicity of propylthiouracil and methimazole. Birth Defects Res B Dev Reprod Toxicol, 2014. 101(4): p. 300-7.

Fast Electrocatalytic Determination of Methimazole at an Activated Glassy Carbon Electrode.[Pubmed:28243269]

Iran J Pharm Res. 2016 Fall;15(4):735-741.

A fast and simple voltammetric method for the determination of Methimazole in pharmaceutical products was reported. A glassy carbon electrode was pretreated by anodization at +1.75 V (vs. SCE) for 5 min, followed by potential cycling in the range of 0.3-1.3 V (20 cycles). The pretreated electrode showed an excellent electrocatalytic effect on the oxidation of Methimazole. Compared with untreated electrode, a large decrease (~300 mV) in the oxidation peak of Methimazole was observed. The oxidation peak current at the new potential (0.4 V vs. SCE) was linearly dependent on the concentration of Methimazole in the range of 7.0 - 130 muM with a detection limit of 3.7 muM (S/N = 3). The method was successfully used in the determination of Methimazole in thyramozol tablets. Due to the simple and fast electrode preparation, there is no need for electrode cleaning or storage.

Methimazole associated eosinophilic pleural effusion: a case report.[Pubmed:28320470]

BMC Pharmacol Toxicol. 2017 Mar 21;18(1):16.

BACKGROUND: Adverse reactions associated to anti-thyroid drugs include fever, rash, arthralgia, agranulocytosis and hepatitis that are thought to be hypersensitivity reactions. Five cases of pleural effusion associated to thionamides have also been reported, two with propylthiouracil and three with carbimazole. CASE PRESENTATION: We report here a case of a 75-year-old man admitted because of unilateral pleural effusion. The patient had a recent diagnosis of hyperthyroidism and 6 days after starting Methimazole complained of pleuritic chest pain. He had elevated C-reactive protein and erythrocyte sedimentation rate and normal white blood cell count and liver enzymes. Chest radiography showed a moderate right pleural effusion and the ultrasound revealed a loculated effusion that was shown to be an eosinophilic exudate. CONCLUSIONS: The temporal relationship between Methimazole intake and the development of pleural effusion combined with the extensive exclusion of alternative causes, namely infectious, neoplastic and primary auto-immune diseases, led to the diagnosis of hypersensitivity reaction to Methimazole. The thionamide was stopped and corticosteroid was started with complete resolution of the pleural effusion in 3 months. Awareness of this rare adverse reaction of anti-thyroid drugs is important and Methimazole can be added to the list of possible etiologies of drug-induced eosinophilic pleural effusion.

Effects of methimazole on Drosophila glucolipid metabolism in vitro and in vivo.[Pubmed:28341216]

Comp Biochem Physiol C Toxicol Pharmacol. 2017 Jun;196:54-60.

Methimazole (MMI) is an antithyroid agent widely used in the treatment of hyperthyroidism, and metabolized by cytochrome P450 enzymes and flavin-containing monooxygenases in mammals. However, drug overdose and the inadequate detoxification of the metabolite(s) are responsible for hepatocellular damage and organ dysfunction. Depending on the desired properties, Drosophila melanogaster has recently emerged as an ideal model organism for the study of human diseases. Here we investigated the changes in metabolic profiles and mRNA expressions related to glucolipid metabolism in response to treatment with MMI in Drosophila. Remarkable loss of lifespan occurred in fruit flies fed on the diets containing 10 or 30mM MMI compared to unsupplemented controls. To examine whether MMI affects glucolipid metabolism in vitro and in vivo, fruit flies were fed diets containing 30mM MMI for two weeks and Drosophila S2 cells were incubated with 300muM MMI for 48h. Measurements of metabolites showed that triglyceride content dramatically decreased (30.56% in vivo and 18.13% in vitro), and glycogen content significantly increased (10.7% in vivo and 126.8% in vitro). Quantitative analyses indicated that mRNA expression levels of Dmfmo1, s6k, dilp2, acc and dilp5 genes involved in metabolic homeostasis were remarkably down-regulated in vivo and in vitro. Meanwhile, the addition of MMI could significantly reduce the lipid droplet content in S2 cells by approximately 25% compared to control subjects. These data may provide a biological basis for the study of MMI on disease symptoms and complications, and discovery of therapeutic treatments.

Novel spiroimidazopyridine derivative SAK3 improves methimazole-induced cognitive deficits in mice.[Pubmed:28279752]

Neurochem Int. 2017 Sep;108:91-99.

Methimazole (MMI) is a first-line therapy used to manage hyperthyroidism and Graves' disease. Despite its therapeutic benefit, chronic MMI administration can lead to hypothyroidism and perturb brain homeostasis in patients, resulting in neuropsychiatric disorders such as depression and cognitive dysfunction. We recently developed the spiroimidazopyridine derivative SAK3 as cognitive enhancer; however, mechanisms underlying its activity remained unclear. Here, we show that SAK3 potentially improves cognitive impairment seen following MMI-induced hypothyroidism. Twenty-four hours after MMI (75 mg/kg, i.p.) treatment, we administered SAK3 (0.1, 0.5 and 1 mg/kg, p.o.) to mice daily for 7 days. MMI treatment alone disrupted olfactory bulb (OB) glomerular structure, as assessed by staining with the olfactory marker protein (OMP), reduced the number of choline acetyl transferase (ChAT)-immunoreactive neurons in medial septum (MS), and significantly impaired cognition. SAK3 (0.5 and 1 mg/kg, p.o.) administration significantly restored the number of cholinergic MS neurons in MMI-treated mice, and SAK3 treatment at a higher dose significantly improved cognitive deficits seen in MMI-treated control mice. Overall, our study suggests that SAK3 treatment could antagonize such impairment in patients with hypothyroidism.