Effects of selenium on short-term control of hyperthyroidism due to Graves' disease treated with methimazole: results of a randomized clinical trial

Thyroid hormones and minerals in immunocorrection of disorders in autoimmune thyroid diseases

Thyroid hormones and essential elements iodine (I), selenium (Se), iron (Fe), copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), etc. play an important role in the work of many organs and systems of the body, including the immune system and the thyroid gland, and a violation of their supply can be the cause of pathological changes in them. In pathology, the interaction between thyroid hormones (TG), minerals and the immune system is disturbed. The review of the literature examines the immunomodulatory role of TG, minerals, their properties, and their participation in the pathogenesis of autoimmune thyroid diseases (AITD). The study of the relationship between the excess or deficiency of minerals and AITD is described. The basis of the development of AITD - Hashimoto's thyroiditis (HT), Graves' disease (GD), Graves' ophthalmopathy (GO) is the loss of immune tolerance to thyroid antigens - thyroid peroxidase (TPO), thyroglobulin (Tg) and thyroid-stimulating hormone receptor (TSH-R). Immune-mediated mechanisms - production of autoantibodies to thyroid antigens and lymphocytic thyroid infiltration - are involved in the pathogenesis of AITD. Insufficiency of regulatory T cells (Treg) and regulatory B cells (Breg), imbalance between Th17-lymphocytes and Treg-lymphocytes, abnormal production of pro-inflammatory cytokines has a significant influence on the progression of AITD. With AITD, the balance between oxidants and antioxidants is disturbed and oxidative stress (OS) occurs. The lack of modern effective pharmacological therapy of AITD prompted us to consider the mechanisms of influence, possibilities of immunocorrection of pathogenetic factors using TG, micro/macronutrients. In order to develop a more effective treatment strategy, as well as approaches to prevention, a critical analysis of the ways of immunotherapeutic use of dietary supplements of I, Se, Zn, Mg and other minerals in AITD was carried out.

Literature Commentary

In this issue of JNO, Drs. Mark L. Moster, Marc J. Dinkin, and Deborah I. Friedman discuss the following 6 articles:Piehl F, Eriksson-Dufva A, Budzianowska A, Feresiadou A, Hansson W, Hietala MA, Håkansson I, Johansson R, Jons D, Kmezic I, Lindberg C, Lindh J, Lundin F, Nygren I, Punga AR, Press R, Samuelsson K, Sundström P, Wickberg O, Brauner S, Frisell T. Efficacy and safety of rituximab for new-onset generalized myasthenia gravis: the RINOMAX randomized clinical trial. JAMA Neurol. 2022;79:1105-1112.Cortese R, Carrasco FP, Tur C, Bianchi A, Brownlee W, De Angelis F, De La Paz I, Grussu F, Haider L, Jacob A, Kanber B, Magnollay L, Nicholas RS, Trip A, Yiannakas M, Toosy AT, Hacohen Y, Barkhof F, Ciccarelli O. Differentiating multiple sclerosis from AQP4-neuromyelitis optica spectrum disorder and MOG-antibody disease with imaging. Neurology. 2022. doi: 10.1212/WNL.0000000000201465.Carelli V, Newman NJ, Yu-Wai-Man P, Biousse V, Moster ML, Subramanian PS, Vignal-Clermont C, Wang AG, Donahue SP, Leroy BP, Sergott RC, Klopstock T, Sadun AA, Rebolleda Fernández G, Chwalisz BK, Banik R, Girmens JF, La Morgia C, DeBusk AA, Jurkute N, Priglinger C, Karanjia R, Josse C, Salzmann J, Montestruc F, Roux M, Taiel M, Sahel JA; the LHON Study Group. Indirect comparison of Lenadogene Nolparvovec gene therapy versus natural history in patients with leber hereditary optic neuropathy carrying the m.11778G>A MT-ND4 mutation. Ophthalmol Ther. 2022. doi: 10.1007/s40123-022-00611-x.Noll C, Hiltensperger M, Aly L, Wicklein R, Afzali AM, Mardin C, Gasperi C, Berthele A, Hemmer B, Korn T, Knier B. Association of the retinal vasculature, intrathecal immunity, and disability in multiple sclerosis. Front Immunol. 2022;13:997043.Mitchell JL, Buckham R, Lyons H, Walker JK, Yiangou A, Sassani M, Thaller M, Grech O, Alimajstorovic Z, Julher M, Tsermoulas G, Brock K, Mollan SP, Sinclair AJ. Evaluation of diurnal and postural intracranial pressure employing telemetric monitoring in idiopathic intracranial hypertension. Fluids Barriers CNS. 2022;19:85.Pan Y, Chen YX, Zhang J, Lin ML, Liu GM, Xu XL, Fan XQ, Zhong Y, Li Q, Ai SM, Xu W, Tan J, Zhou HF, Xu DD, Zhang HY, Xu B, Wang S, Ma JJ, Zhang S, Gan LY, Cui JT, Li L, Xie YY, Guo X, Pan-Doh N, Zhu ZT, Lu Y, Shi YX, Xia YW, Li ZY, Liang D. Doxycycline vs placebo at 12 weeks in patients with mild thyroid-associated ophthalmopathy: a randomized clinical trial. JAMA Ophthalmol. 2022;140:1076-1083.

Non-thionamide antithyroid drug options in Graves' hyperthyroidism

INTRODUCTION

The thionamide anti-thyroid drugs namely carbimazole, methimazole, and propylthiouracil, have been the predominant therapy modality for Graves' hyperthyroidism for over 60 years. Although these agents have proven efficacy and favorable side-effect profiles, non-thionamide alternatives are occasionally indicated in patients who are intolerant or unresponsive to thionamides alone. This review examines the available non-thionamide drug options for the control of Graves' hyperthyroidism and summarizes their clinical utility, efficacy, and limitations.

AREAS COVERED

We reviewed existing literature on mechanisms, therapeutic utility, and side-effect profiles of non-thionamide anti-thyroid drugs. Established non-thionamide agents act on various phases of the synthesis, release, and metabolism of thyroid hormones and comprise historical agents such as iodine compounds and potassium perchlorate as well as drug repurposing candidates like lithium, glucocorticoids, beta-blockers, and cholestyramine. Novel experimental agents in development target key players in Graves' disease pathogenesis including B-cell depletors (Rituximab), CD40 blockers (Iscalimab), TSH-receptor antagonists, blocking antibodies, and immune-modifying peptides.

EXPERT OPINION

Non-thionamide anti-thyroid drugs are useful alternatives in Graves' hyperthyroidism and more clinical trials are needed to establish their safety and long-term efficacy in hyperthyroidism control. Ultimately, the promise for a cure will lie in novel approaches that target the well-established immunopathogenesis of Graves' disease.

Selenium and thyroid diseases

Selenium, a non-metallic element, is a micronutrient essential for the biosynthesis of selenoproteins containing selenocysteine. In adults, the thyroid contains the highest amount of selenium per gram of tissue. Most known selenoproteins, such as glutathione peroxidase, are expressed in the thyroid and are involved in thyroid hormone metabolism, redox state regulation, and maintenance of cellular homeostasis. Some clinical studies have shown that lack of selenium will increase the prevalence of several kinds of thyroid diseases. Selenium treatment in patients with Graves' orbitopathy has been shown to delay disease progression and improve the quality of life. Selenium supplementation in Hashimoto's thyroiditis was associated with the decreased levels of anti-thyroid peroxidase antibody and improved thyroid ultrasound structure. In thyroid cancer, various selenium supplements have shown variable anticancer activity. However, published results remain the conflicting and more clinical evidence is still needed to determine the clinical significance of selenium. This article reviews the strong association between selenium and thyroid disease and provides new ideas for the clinical management of selenium in thyroid disease.

Serum Selenium Levels in Patients With Graves Disease With or Without Thyroid Ophthalmopathy

BACKGROUND

Graves disease is one of the most common autoimmune thyroid diseases. Thyroid has the highest concentration of selenium (Se) in the body. Se plays a crucial role in the functioning of some thyroid enzymes; however, there are controversial results regarding the administration of serum Se levels in patients with Graves disease.

METHODS

In this study, patients with Graves disease with orbitopathy (GO group) or without orbitopathy (GD group) were recruited. Healthy individuals without a history of any disease were enrolled as the control group. Serum Se and thyroid hormone levels, including T3, T4, and thyroid-stimulating hormone (TSH), were measured using atomic absorption and radioimmunoassay techniques, respectively.

RESULTS

In this cross-sectional study, 60 and 56 patients and 58 healthy subjects were included in the GO, GD, and control groups. Serum Se levels in the GO, GD, and control groups were 94.53 ± 25.36 μg/dL, 96.82 ± 30.3 μg/dL, and 102.55 ± 16.53 μg/dL, respectively (P = .193). There was a reverse association between the serum Se level and thyroid hormones, including T3, T4, and TSH, in the GO group. However, serum Se levels exhibited a significant reverse association with T4 and TSH hormones but not with T3 in the GD group.

CONCLUSION

Our results showed no significant differences in the serum Se levels in the GO and GD groups compared with that in the control group. In addition, we did not detect any significant difference in the serum Se levels between the GO and GD groups.

Thyroid eye disease: From pathogenesis to targeted therapies

Thyroid eye disease (TED) is the most common extrathyroidal manifestation of autoimmune Graves’ hyperthyroidism. TED is a debilitating and potentially blinding disease with unclear pathogenesis. Autoreactive inflammatory reactions targeting orbital fibroblasts (OFs) lead to the expansion of orbital adipose tissues and extraocular muscle swelling within the fixed bony orbit. There are many recent advances in the understating of molecular pathogenesis of TED. The production of autoantibodies to cross-linked thyroid-stimulating hormone receptor and insulin-like growth factor-1 receptor (IGF-1R) activates OFs to produce significant cytokines and chemokines and hyaluronan production and to induce adipocyte differentiation. In moderately severe active TED patients, multicenter clinical trials showed that inhibition of IGF-1R with teprotumumab was unprecedentedly effective with minimal side effects. The emergence of novel biologics resulted in a paradigm shift in the treatment of TED. We here review the literature on advances of pathogenesis of TED and promising therapeutic targets and drugs.

Add-On Effect of Selenium and Vitamin D Combined Supplementation in Early Control of Graves' Disease Hyperthyroidism During Methimazole Treatment

Prompt and stable control of hyperthyroidism is fundamental to avoid the detrimental effects of thyroid hormone excess, and antithyroid drugs, mainly methimazole (MMI), represent the first-line treatment for Graves' disease (GD) hyperthyroidism. Decreased serum concentrations of selenium (Se) and calcifediol (25(OH)D, VitD) have been reported in newly diagnosed GD patients in observational studies. Low Se levels might exacerbate oxidative stress by compromising the antioxidant machinery's response to reactive oxygen species, and low VitD levels might hamper the anti-inflammatory immune response. We performed a randomized controlled clinical trial (EudraCT 2017-00505011) to investigate whether Se and cholecalciferol (VitD) addition to MMI is associated with a prompter control of hyperthyroidism. Forty-two consecutive patients with newly-onset GD and marginal/insufficient Se and VitD levels were randomly assigned to treatment with either MMI monotherapy or MMI combined with Se and VitD. Se treatment was withdrawn after 180 days, while the other treatments were continued. Combination therapy resulted in a significantly greater reduction in serum FT4 concentration at 45 days (-37.9 pg/ml, CI 95%, -43.7 to -32.2 pg/ml) and 180 days (-36.5 pg/ml, CI 95%, -42 to -30.9 pg/ml) compared to MMI monotherapy (respectively: -25.7 pg/ml, CI 95%, -31.6 to -19.7 pg/ml and -22.9 pg/ml, CI 95%, -28 to -17.3 pg/ml, p 0.002). Data at 270 days confirmed this trend (-37.8 pg/ml, CI 95%, -43.6 to -32.1 pg/ml vs -24.4 pg/ml, CI 95%, -30.3 to -18.4 pg/ml). The quality of life (QoL) score was investigated by the validated "Thyroid-related Patient-Reported Outcome" questionnaire (ThyPRO). ThyPRO composite score showed a greater improvement in the intervention group at 45 days (-14.6, CI 95%, -18.8 to -10.4), 180 (-9, CI 95%, -13.9 to -4.2) and 270 days (-14.3, CI 95%, -19.5 to -9.1) compared to MMI group (respectively, -5.2, CI 95%, -9.5 to -1; -5.4, CI 95%, -10.6 to -0.2 and -3.5, CI 95%, -9 to -2.1, p 0-6 months and 6-9 months <0.05). Our results suggest that reaching optimal Se and VitD levels increases the early efficacy of MMI treatment when Se and VitD levels are suboptimal.

Selenium: An Element of Life Essential for Thyroid Function

Selenium (Se), a microelement essential for life, is critical for homeostasis of several critical functions, such as those related to immune-endocrine function and signaling transduction pathways. In particular, Se is critical for the function of the thyroid, and it is particularly abundant in this gland. Unfortunately, Se deficiency is a very common condition worldwide. Supplementation is possible, but as Se has a narrow safety level, toxic levels are close to those normally required for a correct need. Thus, whether the obtaining of optimal selenium concentration is desirable, the risk of dangerous concentrations must be equally excluded. This review addressed the contribution by environment and food intake on Se circulating levels (e.g., geographical factors, such as soil concentration and climate, and different quantities in food, such as nuts, cereals, eggs, meat and fish) and effects related to its deficiency or excess, together with the role of selenium and selenoproteins in the thyroid pathophysiology (e.g., Hashimoto's thyroiditis and Graves' disease).

Erythroid microRNA and oxidant status alterations in l-thyroxine-induced hyperthyroid rats: effects of selenium supplementation

BACKGROUND

Hypermetabolic state in hyperthyroidism causes oxidative stress. Erythrocytes are the cells that are involved in oxidant equilibrium in an organism and contain microRNA (miRNA). Selenium, which is an essential element for an organism, has antioxidant properties. The present study was aimed at investigating the effects of selenium supplementation in hyperthyroidism, on pro- and antioxidant enzymes, and miRNA (miR-144 and miR-451) expressions in the erythrocytes.

METHODS

Forty-eight Sprague-Dawley male rats were divided into 6 groups; control group, group fed with 0.5 mg/kg sodium selenite; group fed with 1 mg/kg sodium selenite; hyperthyroid group; hyperthyroid group fed with 0.5 mg/kg sodium selenite; and hyperthyroid group fed with 1 mg/kg sodium selenite. Malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), miR-144, and miR-451 expression levels were studied in erythrocyte hemolysates.

RESULTS

MDA levels were increased in the hyperthyroid group compared to the control group, and the group fed with 0.5 mg/kg sodium selenite (P<0.001 and P<0.01, respectively). GSH levels were increased in the hyperthyroid group and the hyperthyroid group fed with 0.5 mg/kg sodium selenite compared to the control group (P<0.001, and P<0.05, respectively). GSH levels of the hyperthyroid group fed with 1 mg/kg sodium selenite were decreased when compared with the hyperthyroid group (P<0.05). SOD levels of the hyperthyroid group were increased when compared with the control group (P<0.05, and P<0.001, respectively). Similarly, SOD levels of the hyperthyroid group fed with 1 mg/kg sodium selenite were lower than the hyperthyroid group (P<0.01). miR-144 values were increased in the hyperthyroid group and the hyperthyroid group fed with 0.5 mg/kg sodium selenite compared to the control group (P<0.001, and P<0.05 respectively). miR-451 expression was increased significantly in the hyperthyroid group compared to the control group (P<0.05).

CONCLUSIONS

Our findings showed that MDA, SOD and GSH levels increased, and miR-144 and miR-451 expressions changed in hyperthyroidism. Supplementation of 1 mg/kg sodium selenite was more effective than 0.5 mg/kg sodium selenite for normalizing the MDA, GSH, SOD, and miRNA levels in the hyperthyroid group.

Selenium in the Treatment of Graves' Hyperthyroidism and Eye Disease

Based on the role of oxidative stress in the pathogenesis of Graves' hyperthyroidism (GH) and Graves' Orbitopathy (GO), a therapy with the antioxidant agent selenium has been proposed and a number of studies have been performed, both in vitro and in vivo. In GH, reactive oxygen species (ROS) contribute to the thyroid and peripheral tissues damage. In GO, tissue hypoxia, as well as ROS, are involved in the typical changes that occur in fibroadipose orbital tissue and the perimysium of extraocular muscles. Antioxidants have been proposed to improve the effects of antithyroid drugs in GH patients, as well as the remodeling of orbital tissues in patients with GO. Here, we reviewed the literature on the possible beneficial effects and clinical use of selenium in the management of patients with GH and GO. A randomized clinical trial on the use of selenium in patients with mild GO provided evidence for a beneficial effect; no data are available on more severe forms of GO. Although the real effectiveness of selenium in patients with GH remains questionable, its use in the management of mild GO is generally believed to be beneficial, and selenium administration has been included in the clinical practice for the patients with mild eye disease.

Oxidative Stress in Graves Disease and Graves Orbitopathy

Oxidative stress is involved in the pathogenesis of Graves hyperthyroidism (GH) and Graves orbitopathy (GO) and an antioxidant approach has been proposed for both. In GH, a disbalance of the cell redox state is associated with thyroid hyperfunction and antithyroid medications may reduce oxidative stress. Tissue hypoxia participates in the pathogenesis of GO, and oxygen free radicals are involved in the typical changes of orbital tissues as reported by in vitro and clinical studies. Antioxidant agents, especially selenium, have been proposed as a therapeutic option for GH and GO. A clinical study regarding the use of selenium in mild GO has provided evidence for a beneficial effect in the short term, even though its beneficial effects in the long term are still to be investigated. In addition to selenium, a protective role of other antioxidant agents, i.e., quercetin, enalapril, vitamin C, N-acetyl-L-cysteine and melatonin has been suggested by in vitro studies, although clinical studies are lacking. Here, we review the role of oxidative stress and antioxidant agents in GH and GO.

Oxidative stress as a key feature of autoimmune thyroiditis: an update

INTRODUCTION

Oxidative stress has been proposed as one of the factors concurring in the pathophysiology of autoimmune thyroid diseases. Reactive oxygen species are the main expression of oxidative stress in biological systems, and their production can overcome antioxidant defenses ultimately leading to cell damage, apoptosis, and death. The present review was aimed at describing the state of the art of the relationships between oxidative stress and autoimmune thyroiditis. The most used biomarkers of oxidative stress and their correlation with thyroid function are reported.

EVIDENCE ACQUISITION

We conducted a search of the literature in the English language starting from 2000, using the following search terms: "Hashimoto thyroiditis," "autoimmune thyroiditis," "hypothyroidism," "hyperthyroidism," "oxidative stress," "oxidants," "antioxidant," "advanced glycation end products." Both clinical studies and animal models were evaluated.

EVIDENCE SYNTHESIS

Data form clinical studies clearly indicate that the balance between oxidants and antioxidants is shifted towards the oxidative side in patients with autoimmune thyroiditis, suggesting that oxidative stress may be a key event in the pathophysiology of the disease, irrespective of thyroid function. Studies in animal models, such as the NOD.H2h4 mouse, confirm that thyroidal accumulation of ROS plays a role in the initiation and progression of autoimmune thyroiditis.

CONCLUSIONS

Oxidant/antioxidant imbalance represent a key feature of thyroid autoimmunity. Oxidative stress parameters could be used as biochemical markers of chronic inflammation, to better predict the disease evolution along its natural history. Dietary habits and antioxidant supplements may provide protection from autoimmunity, opening new perspectives in the development of more tailored therapies.

Challenges and perspectives of selenium supplementation in Graves' disease and orbitopathy

PURPOSE

This review focuses on the results of prospective randomized clinical trials and the conclusions from respective meta-analyses in order to summarize experiences with adjuvant selenium (Se) supplementation in Graves' hyperthyroidism and orbitopathy, while identifying ambiguous findings and highlighting important open research issues.

METHODS

We searched the PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL) through May 31, 2019, for relevant studies.

RESULTS

The available evidence concerning routine use of Se in the treatment of Graves' hyperthyroidism remains ambiguous. Results of meta-analyses, including ten RCTs, suggest that adjuvant Se supplementation can enhance the restoration of biochemical euthyroidism. Unfortunately, these results must be judged cautiously owing to several important limitations. Moreover, an in-depth analysis of relevant long-term clinical measures of therapeutic success (such as remission rate after antithyroid drug treatment), besides surrogate markers (for example, hormone or autoantibody concentrations), is generally missing. Based on a single study, Se supplementation is recommended in patients with mild orbitopathy of short duration because it may decrease inflammation and eye-specific symptoms while also achieving a marked improvement in disease-specific quality of life. The effects of Se supplementation on moderate-to-severe orbitopathy remain as yet unknown.

CONCLUSIONS

Additional randomized clinical trials with clinically relevant endpoints are urgently needed to further aid in clinical decision-making, including better stratification of Graves' disease patients, who are most likely to benefit from Se supplementation.

Selenium in thyroid disorders - essential knowledge for clinicians

In the 1990s, selenium was identified as a component of an enzyme that activates thyroid hormone; since this discovery, the relevance of selenium to thyroid health has been widely studied. Selenium, known primarily for the antioxidant properties of selenoenzymes, is obtained mainly from meat, seafood and grains. Intake levels vary across the world owing largely to differences in soil content and factors affecting its bioavailability to plants. Adverse health effects have been observed at both extremes of intake, with a narrow optimum range. Epidemiological studies have linked an increased risk of autoimmune thyroiditis, Graves disease and goitre to low selenium status. Trials of selenium supplementation in patients with chronic autoimmune thyroiditis have generally resulted in reduced thyroid autoantibody titre without apparent improvements in the clinical course of the disease. In Graves disease, selenium supplementation might lead to faster remission of hyperthyroidism and improved quality of life and eye involvement in patients with mild thyroid eye disease. Despite recommendations only extending to patients with Graves ophthalmopathy, selenium supplementation is widely used by clinicians for other thyroid phenotypes. Ongoing and future trials might help identify individuals who can benefit from selenium supplementation, based, for instance, on individual selenium status or genetic profile.

Selenium Supplementation May Decrease Thyroid Peroxidase Antibody Titer via Reducing Oxidative Stress in Euthyroid Patients with Autoimmune Thyroiditis

OBJECTIVE

Selenium, as an antioxidant, has been implicated in the development of autoimmune thyroiditis (AIT). Many studies showed selenium supplementation could decrease thyroid autoantibodies in patients with AIT. However, the underlying mechanisms have not been well determined. Therefore, we performed a clinical study to investigate the possible mechanism of beneficial effects of selenium treatment on AIT patients.

METHODS

Forty euthyroid patients with AIT were randomized into two groups. Group I was treated with 200 μg/day selenium supplementation, and group II received a placebo over a 3-month period. Thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), antithyroglobulin antibody (TgAb), malondialdehyde (MDA), total antioxidant capacity (TAC), and superoxide dismutase (SOD) were measured before and 3 months after treatments. Additionally, twenty healthy volunteers also served as a control group for the evaluation of such parameters in basic condition.

RESULTS

Totally, 32 patients (group I, n = 18; group II, n = 14) completed the clinical study and were incorporated into the statistics. MDA level was higher and SOD activity and TAC were lower in patients compared to healthy individuals. After 3 months, TPOAb titer significantly decreased within group I (P < 0.001) but did not change within group II (P=0.001). There were also no statistically significant changes in TSH and TgAb titers within the two groups (all P > 0.05). Additionally, decreased MDA level (from 6.8 ± 1.3 nmol/ml to 4.9 ± 0.7 nmol/ml; P < 0.001) and increased TAC (from 10.0 ± 1.9 mmol/l to 12.9 ± 3.1 mmol/l; P=0.003) and SOD activity (from 72.3 ± 10.3 U/ml to 84.3 ± 13.2 U/ml; P=0.007) were simultaneously observed after 3 months' selenium treatment. Moreover, there was a negative correlation between TAC and TgAb/TPOAb and a positive correlation between MDA and TgAb/TPOAb in AIT patients.

CONCLUSIONS

Our findings support the hypothesis that selenium treatment could decrease TPOAb titer via enforcing the defense against oxidative stress in euthyroid patients with AIT, which may be a potential underlying mechanism.

Safety of long-term antithyroid drug treatment? A systematic review

Continued low-dose MMI treatment for longer than 12-18 months may be considered in patients not in remission. However, ATDs are not free from adverse effects. We undertook a systematic review to clarify safety of long-term ATD treatment. Medline and the Cochrane Library for trials published between 1950 and Nov 2018 were systematically searched. We included original studies containing data for long-term (> 18 months) ATD treatment. Two reviewers independently extracted data from included trials and any disagreement was adjudicated by consensus. Of 615 related articles found, 12 fulfilled the criteria. Six articles had data for adults, five for non-adults and one article had data for both groups. The sample sizes ranged between 20 and 249 individuals, and the mean duration of ATD treatment ranged between 2.1 and 14.2 years. Considering all data from 1660 patients treated with ATD for a mean duration of 5.8 years (around 10,000 patient-years), major complications occurred only in 14 patients: 7 severe agranulocytosis, 5 severe liver damage, one ANCA-associated glomerulonephritis and one vasculitis with small cutaneous ulcerations. Minor complications rates were between 2 and 36%, while more complications were in higher doses and in the children. The most reported AE was cutaneous reaction; the other adverse events were elevated liver enzymes, leukocytopenia, arthritis, arthralgia, myalgia, thrombocytopenia, fever, nausea and oral aphthous. Long-term ATD treatment is safe, especially in low dose and in adults, indicating that it should be considered as an earnest alternative treatment for GD.

Nutraceutical Supplements in the Thyroid Setting: Health Benefits beyond Basic Nutrition

In recent years, there has been a growing interest in nutraceuticals, which may be considered as an efficient, preventive, and therapeutic tool in facing different pathological conditions, including thyroid diseases. Although iodine remains the major nutrient required for the functioning of the thyroid gland, other dietary components play important roles in clinical thyroidology—these include selenium, l-carnitine, myo-inositol, melatonin, and resveratrol—some of which have antioxidant properties. The main concern regarding the appropriate and effective use of nutraceuticals in prevention and treatment is due to the lack of clinical data supporting their efficacy. Another limitation is the discrepancy between the concentration claimed by the label and the real concentration. This paper provides a detailed critical review on the health benefits, beyond basic nutrition, of some popular nutraceutical supplements, with a special focus on their effects on thyroid pathophysiology and aims to distinguish between the truths and myths surrounding the clinical use of such nutraceuticals.

Effects of selenium and vitamin C on the serum level of antithyroid peroxidase antibody in patients with autoimmune thyroiditis

PURPOSE

Selenium (Se), an essential trace element, has been implicated in pathogenesis of autoimmune thyroiditis (AIT). Most studies attributed the immune modulating effects of Se to its antioxidant properties. However, there is insufficient evidence to support the use of selenium supplementation or other antioxidants in patients with AIT. This clinical trial was designed to investigate the impact of Se and vitamin C supplementation on antithyroid peroxidase antibody (TPO-Ab) level in patients with AIT.

METHODS

One hundred and two subjects aged 15-78 years were randomized into three groups. Group one (GI) (n = 38) was treated with 200 μg/day sodium selenite, group two (GII) (n = 36) received 500 mg vitamin C/day, and group three (GIII) (n = 28) received placebo over a 3-month period. Thyroid stimulating hormone (TSH), TPO-Ab, antithyroglobulin antibody (Tg-Ab) and Se concentrations were once measured before treatment and at the end of the study.

RESULTS

After 3 months, TPO-Ab concentrations decreased within Se and vitamin C-treated groups, but did not change in the placebo subjects. In this regard, there was no significant difference between the groups. We also did not find any statistically significant difference in TSH and Tg-Ab levels within and between the groups. At the end of the study, Se level was significantly higher in GI compared with GII and GIII.

CONCLUSION

Our findings supported the hypothesis of antioxidant beneficial effects of Se in AIT. However, it was not superior to vitamin C, regarding its effects on thyroid-specific antibodies.

Role of Selenium Intake for Risk and Development of Hyperthyroidism

PURPOSE

To investigate the importance of dietary selenium (Se) for hyperthyroidism.

METHODS

We performed a more in-depth analysis of a large cross-sectional study of 6152 participants from two counties within the Shaanxi Province, China. These counties are characterized by different habitual Se intake. We investigated the effects of a different dietary Se supply (0.02, 0.18, 0.6, or 2.0 ppm Se) on disease development in a mouse model of Graves disease (GD).

RESULTS

The cross-sectional study revealed a comparable prevalence of hyperthyroidism, irrespective of Se intake, in both counties. However, an unexpected sex-specific difference was noted, and Se deficiency might constitute a risk factor for hyperthyroidism, especially in males. In a mouse model, pathological thyroid morphology was affected, and greater Se intake exerted some protecting effects on the pathological distortion. Circulating thyroid hormone levels, malondialdehyde concentrations, total antioxidant capacity, and the titer of GD-causing TSH receptor autoantibodies were not affected by Se. Expression analysis of the transcripts in the spleen indicated regulatory effects on genes implicated in the immune response, erythropoiesis, and oxygen status. However, the humoral immune response, including the CD4/CD8 or T-helper 1/T-helper 2 cell ratio and the concentration of regulatory T cells, was similar between the experimental groups, despite the difference in Se intake.

CONCLUSIONS

Our data have highlighted a sexual dimorphism for the interaction of Se and thyroid disease risk in humans, with indications of a local protective effects of Se on thyroid gland integrity, which appears not to be reflected in the circulating biomarkers tested.

A 2018 European Thyroid Association Survey on the Use of Selenium Supplementation in Graves' Hyperthyroidism and Graves' Orbitopathy

OBJECTIVE

Selenium (Se) supplementation has been suggested in the treatment of Graves' disease (GD). We sought to investigate Se prescription patterns for GD across European countries.

METHODS

Members of the European Thyroid Association were invited to participate in an online survey investigating the use of Se in GD either without or with orbitopathy (GO). Of 872 invited members, 244 (28%) completed the survey. After exclusion of basic scientists and non-European members, 197 responses were retrieved out of clinical trials (nearly half of clinician members), of whom 61 do not use Se. Thus, 136 respondents remained for further analyses.

RESULTS

Among the 136 analyzed respondents, most (64.7%) were not aware of the Se status in their populations, did not assess Se levels (78.7%), nor considered iodine status (74.3%). In GD without GO, 38.2% recommend Se supplementation ("sometimes" [27.2%], "frequently" [5.9%] or "always" [5.1%]). When GO occurs, 94.1% recommend Se supplementation ("sometimes" [39%], "frequently" [30.1%] or "always" [25%]). Of these, 60.1% recommend Se as an alternative to watchful waiting in patients with mild ocular involvement and 44.9% as an adjuvant to the established treatment modalities in patients with moderate to severe ocular involvement.

CONCLUSIONS

In Graves' hyperthyroidism without GO, 38.2% of ETA (European Thyroid Association) members recommend Se supplementation. Conversely, Se is recommended by the majority of respondents in GO, both in patients with mild and moderate to severe ocular involvement. This clinical practice is partially in disagreement with current European treatment guidelines that recommend Se as a 6-month treatment in mild GO only.

Selenium and Selenoproteins in Immune Mediated Thyroid Disorders

Selenium is an essential micronutrient that is required for the synthesis of selenocysteine-containing selenoproteins, processing a wide range of health effects. It is known that the thyroid is one of the tissues that contain more selenium. The “selenostasis” maintenance seems to contribute to the prevention of immune mediated thyroid disorders. Prospective, observational studies, randomized, controlled studies evaluating selenium supplementation, and review articles that are available in Medline and PubMed have undergone scrutiny. The differences concerning methodology and results variability have been analyzed. Several authors support the idea of a potential efficacy of selenium (mainly selenomethionine) supplementation in reducing antithyroperoxidase antibody levels and improve thyroid ultrasound features. In mild Graves’ orbitopathy, selenium supplementation has been associated with a decrease of the activity, as well as with quality of life improvement. Future research is necessary to clearly understand the selenium supplementation biologic effects while considering the basal selenium levels/biomarkers, selenoprotein gene polymorphisms that may be involved, underlying comorbidities and the major clinical outcomes.

Effects of Selenium Supplementation on Graves' Disease: A Systematic Review and Meta-Analysis

Low selenium status is associated with increased risk of Graves' disease (GD). While several trials have discussed the efficacy of selenium supplementation for thyroid function, in GD patients, the effectiveness of selenium intake as adjuvant therapy remains unclear. In this systematic review and meta-analysis, we aimed to determine the efficacy of selenium supplementation on thyroid function in GD patients. Two reviewers searched PubMed, Web of Science, the Cochrane Central Register of Controlled Trials, and four Chinese databases for studies published up to October 31, 2017. RCTs comparing the effect of selenium supplementation on thyroid hyperfunction in GD patients on antithyroid medication to placebo were included. Serum free thyroxine (FT4), free triiodothyronine (FT3), thyrotrophic hormone receptor antibody (TRAb), and thyroid-stimulating hormone (TSH) levels were assessed. Ten trials involving 796 patients were included. Random-effects meta-analyses in weighted mean difference (WMD) were performed for 3, 6, and 9 months of supplementation and compared to placebo administration. Selenium supplementation significantly decreased FT4 (WMD=-0.86 [confidence interval (CI)-1.20 to -0.53]; p=0.756; I2=0.0%) and FT3 (WMD=-0.34 [CI-0.66 to -0.02]; p=0.719; I2=0.0%) levels at 3 months, compared to placebo administration; these findings were consistent at 6 but not 9 months. TSH levels were more elevated in the group of patients taking selenium than in the control group at 3 and 6, but not 9 months. TRAb levels decreased at 6 but not 9 months. At 6 months, patients on selenium supplementation were more likely than controls to show improved thyroid function; however, the effect disappeared at 9 months. Whether these effects correlate with clinically relevant measures remains to be demonstrated.

Selenium in Graves Hyperthyroidism and Orbitopathy

PURPOSE

To review the in vitro and in vivo studies supporting a role of selenium for the treatment of mild Graves orbitopathy.

METHODS

Review of the current literature on the role of selenium in the management of Graves orbitopathy.

RESULTS

Graves orbitopathy (GO) is a disfiguring and disabling disorder usually observed in patients with Graves hyperthyroidism, and more rarely in patients with hypothyroid autoimmune thyroiditis or in the absence of overt thyroid dysfunction. Noninvasive treatments include intravenous glucocorticoids and orbital radiotherapy and are generally offered to patients with moderately severe GO. In contrast, patients with mild GO are generally treated only with local measures. Thus, the benefits of intravenous glucocorticoids in mild GO are limited and do not justify the risks that the treatment carries. However, a medical treatment for mild GO is heavily wanted, as a relevant proportion of patients have a significant decrease in their quality of life, and GO can progress into more severe forms. Because of the role of oxidative stress in the pathogenesis of GO, an antioxidant approach has been proposed and the antioxidant agent selenium has been shown to be effective for GO.

CONCLUSION

Studies have shown that a 6-month course of sodium selenite can improve the course of mild GO and prevent deterioration when compared with placebo.

Antioxidant effects of β-carotene, but not of retinol and vitamin E, in orbital fibroblasts from patients with Graves' orbitopathy (GO)

BACKGROUND

Oxidative stress is involved in the pathogenesis of Graves' orbitopathy (GO) and several antioxidant agents, namely, selenium, quercetin, enalapril, vitamin C, N-acetyl-L-cysteine, and melatonin, have been shown to reduce oxidative stress and its consequences in primary culture of orbital fibroblasts. In addition, selenium is effective for the treatment of mild GO. Here, we investigated the action of three additional antioxidants in orbital fibroblasts, namely, retinol, β-carotene, and vitamin E.

METHODS

Primary cultures of orbital fibroblasts were established from GO patients and control subjects. To induce oxidative stress, cells were treated with H₂O₂, after which glutathione disulfide (GSSG) (a parameter of oxidative stress), cell proliferation, hyaluronic acid, TNFα, IFNγ, and IL1β were measured.

RESULTS

H₂O₂-dependent oxidative stress (augmented GSSG) was associated with increased cell proliferation and cytokine release. All the three antioxidant substances reduced GSSG in both GO and control fibroblasts. β-carotene reduced proliferation in GO, but not in control fibroblasts. IL1β was reduced by all three substances. Retinol reduced IFNγ in GO and control fibroblasts.

CONCLUSIONS

Our study supports an antioxidant role of retinol, β-carotene, and vitamin E in orbital fibroblasts from patients with GO and provides a basis for a possible clinical use these substances.

A genome-wide DNA methylation analysis in peripheral blood from patients identifies risk loci associated with Graves' orbitopathy

OBJECTIVE

Graves' orbitopathy (GO) is an inflammatory orbital disease of autoimmune origin with the potential to cause severe functional and psychosocial effects. The pathogenesis has not been fully elucidated. We investigated whether DNA methylation was associated with GO incidence in Chinese patients.

MATERIALS AND METHODS

Six GO patients and six age-matched controls were recruited, and genome-wide DNA methylation patterns were analyzed in their peripheral blood. t tests were performed to determine differential methylated sites in genomic regions and the univariable logistic regression analyses was performed to evaluate their risk with GO incidence. Cluster analysis and principal component analysis (PCA) were performed to determine the effects of the extracted differentially methylated sites.

RESULTS

One hundred and forty-eight differentially methylated sites were identified, including CD14 (fold change = 4.31, p = 0.005), IL17RE (fold change = 2.128, p = 0.005), and DRD4 (fold change = 0.25, p = 0.004), and were supported by cluster and PCA analyses. Univariable logistic regression analyses showed that the methylation patterns at 12 loci were associated with GO incidence. The relative risk per 1% decrease in methylation at ZCCHC6 and GLI3 was 0.15 (95% CI 0.03-0.91; p = 0.039) and 0.65 (95% CI 0.42-0.98; p = 0.042), respectively. Pearson correlation analyses demonstrated that methylation levels at IL17RE were positively associated with Clinical Activity Score (CAS) (r = 0.967, p < 0.05).

CONCLUSIONS

Our results demonstrate that differential methylation levels at analyzed sites (genes) may be risk markers of GO. DNA methylation analysis could provide new insights into understanding the disease and provide new treatment strategies for GO in Chinese patients.

Action of three bioavailable antioxidants in orbital fibroblasts from patients with Graves' orbitopathy (GO): a new frontier for GO treatment?

OBJECTIVE

Oxidative stress is involved in the pathogenesis of Graves' orbitopathy (GO) and an antioxidant approach has been advocated for GO treatment. Here, we investigated the action of three antioxidants in orbital fibroblasts, namely, vitamin C, N-acetyl-L-cysteine, and melatonin.

METHODS

Primary cultures of orbital fibroblasts from six GO patients and six control subjects were established. Cells were treated with H₂O₂ to induce oxidative stress. Cell vitality assays were performed to determine the non-cytotoxic dose of each antioxidant. The following assays were performed: glutathione disulfide (GSSG), as a measure of oxidative stress, cell proliferation, hyaluronic acid (HA), TNFα, IFNγ, and IL1β.

RESULTS

H₂O₂ induced oxidative stress (augmented GSSG), increased cell proliferation as well as cytokine release, but did not affect HA release. All of the three antioxidant substances reduced H₂O₂-dependent oxidative stress. Vitamin C reduced proliferation in GO, but not in control fibroblasts. N-acetyl-L-cysteine reduced proliferation and IFNγ in GO, and HA and IL1β in both GO and control fibroblasts. Melatonin reduced IL1β and HA in GO and control fibroblasts, and IFNγ only in GO fibroblasts.

CONCLUSIONS

Our study provides evidence in support of an antioxidant role of vitamin C, N-acetyl-L-cysteine and melatonin in orbital fibroblasts. Some of the effects of these compounds are exclusive to GO fibroblasts, whereas some other are observed also in control fibroblasts. Our observations provide a basis for a possible clinical use of these substances in patients with GO.

Serum selenium and selenoprotein-P levels in autoimmune thyroid diseases patients in a select center: a transversal study

OBJECTIVE

Selenium (Se) supplementation has been used to help prevent the progression of Graves' ophthalmopathy (GO) and autoimmune thyroid diseases (AITD) patients. We investigated Se serum and selenoprotein P (SePP) levels in Graves' disease (GD) with and without GO, Hashimoto's thyroiditis (HT) patients and in 27 control individuals (C).

SUBJECTS AND METHODS

We studied 54 female and 19 male patients: 19 with GD without GO, 21 GD with GO, 14 with HT and 19 with HT+LT4. Se values were measured using graphite furnace atomic absorption spectrophotometry. Serum SePP levels were measured by ELISA.

RESULTS

Median Se levels were similar among all groups; GD patients: 54.2 (46.5-61.1 μg/L), GO: 53.6 (43.5-60.0 μg/L), HT: 51.9 (44.6-58.5 μg/L), HT+LT4 54.4 (44-63.4) and C group patients: 56.0 (52.4-61.5 μg/L); P = 0.48. However, serum SePP was lower in GO patients: 0.30 (0.15-1.05 μg/mL) and in HT patients: 0.35 (0.2-1.17 μg/mL) compared to C group patients: 1.00 (0.564.21 μg/mL) as well as to GD patients: 1.19 (0.62-2.5 μg/mL) and HT+LT4 patients: 0.7 (0,25-1.95); P = 0.002. Linear regression analysis showed a significant relationship between SePP and TPOAb values (r = 0.445, R2 = 0.293; P < 0.0001). Multiple regression analysis found no independent variables related to Se or SePP.

CONCLUSION

A serum Se concentration was lower than in some other countries, but not significantly among AITD patients. The low serum SePP levels in GO and HT patients seems to express inflammatory reactions with a subsequent increase in Se-dependent protein consumption remains unclear.

Profiling of selenium absorption and accumulation in healthy subjects after prolonged L-selenomethionine supplementation

PURPOSE

Autoimmune thyroiditis and its complications for the reproductive system are a growing problem. Selenium is a common ingredient in numerous food supplements recommended for thyroiditis and pregnancy. A fast, simple method to measure serum selenium concentration will improve knowledge of its pharmacokinetics and toxicity.

AIM

To validate a useful method to measure serum selenium concentration and to study selenium absorption and accumulation in a prospective interventional study of prolonged treatment.

METHODS

Thirty healthy volunteers received a single dose of L-selenomethionine one tablet (83 mcg) (Phase 1), a single dose of two tablets (Phase 2), and two tablets daily for 14 days (Phase 3). Total selenium and selenium time profiles were generated by serial sampling (T0, T3, T6, T12, and T24 hours after ingestion-Phases 1 and 2; and T0 and T24 hours-Phase 3). Selenium concentration was investigated by open-vessel acid digestion of small serum volumes followed by hydride generation atomic fluorescence spectroscopy analysis.

RESULTS

There was a significant increase in serum selenium concentration (mcg/L) in all treatment phases. Significantly increased levels were reached at T3 in Phase 1 (baseline: 76.5 ± 2.47; T3: 82.8 ± 3.28) and at T6 in Phase 2 (83.8 ± 3.46). They remained significantly increased at T12 in Phase 1 and T24 in Phase 2 (79.03 ± 2.69). There was significant selenium accumulation after prolonged intake (14 days) (102.13 ± 5.61).

CONCLUSIONS

Prolonged selenomethionine administration increases circulating blood selenium concentration and hydride generation atomic fluorescence spectroscopy enables its accurate quantification.

Double-Blind, Placebo-Controlled, Randomized Trial of Selenium in Graves Hyperthyroidism

CONTEXT

Supplemental selenium (Se) may affect the clinical course of Graves disease (GD).

OBJECTIVE

Evaluate efficacy of add-on Se on medical treatment in GD.

DESIGN

Double-blind, placebo-controlled, randomized supplementation trial.

SETTING

Academic endocrine outpatient clinic.

PATIENTS

Seventy untreated hyperthyroid patients with GD.

INTERVENTION

Additionally to methimazole (MMI), patients received for 24 weeks either sodium selenite 300 µg/d po or placebo. MMI was discontinued at 24 weeks in euthyroid patients.

MAIN OUTCOME MEASURES

Response rate (week 24), recurrence rate (week 36), and safety.

RESULTS

A response was registered in 25 of 31 patients (80%) and in 27 of 33 (82%) at week 24 [odds ratio (OR) 0.93; 95% confidence interval (CI), 0.26 to 3.25; P = 0.904] in the Se (+MMI) and placebo (+MMI) groups, respectively. During a 12-week follow-up, 11 of 23 (48%) and 12 of 27 (44%) relapsed (OR 1.13; 95% CI, 0.29 to 2.66; P = 0.81) in the Se and placebo groups, respectively. Serum concentrations of Se and selenoprotein P were unrelated to response or recurrence rates. At week 36, 12 of 29 (41%) and 15 of 33 (45%) were responders and still in remission in the Se and placebo groups, respectively (OR 0.85; 95% CI, 0.31 to 2.32; P = 0.80). Serum levels of free triiodothyronine/free tetraiodothyronine, thyroid-stimulating hormone receptor antibody, prevalence of moderate to severe Graves orbitopathy, thyroid volume, and MMI starting dose were significantly lower in responders than in nonresponders. A total of 56 and 63 adverse events occurred in the Se and placebo groups, respectively (P = 0.164), whereas only one drug-related side effect (2.9%) was noted in 35 patients on placebo + MMI.

CONCLUSIONS

Supplemental Se did not affect response or recurrence rates in GD.

Is selenium supplementation in autoimmune thyroid diseases justified?

PURPOSE OF REVIEW

This review provides an appraisal of recent evidence for or against selenium supplementation in patients with autoimmune thyroid diseases, and discusses possible effect mechanisms.

RECENT FINDINGS

Epidemiological data suggest an increased prevalence of autoimmune thyroid diseases under conditions of low dietary selenium intake. Two systematic reviews have evaluated controlled trials among patients with autoimmune thyroiditis and report that selenium supplementation decreases circulating thyroid autoantibodies. The immunomodulatory effects of selenium might involve reducing proinflammatory cytokine release. However, clinically relevant effects of selenium supplementation, including improvement in quality of life, are more elusive. In Graves' disease, some, but not all, trials indicate that adjuvant selenium supplementation enhances the restoration of biochemical euthyroidism, and might benefit patients with mild Graves' orbitopathy.

SUMMARY

The use of selenium supplementation as adjuvant therapy to standard thyroid medication may be widespread, but a growing body of evidence yields equivocal results. The available evidence from trials does not support routine selenium supplementation in the standard treatment of patients with autoimmune thyroiditis or Graves' disease. However, correction of moderate to severe selenium deficiency may offer benefits in preventing, as well as treating, these disorders. Molecular mechanisms have been proposed, but further studies are needed.

Does Graves' Orbitopathy Ever Disappear? Answers to an Old Question

OBJECTIVES

There is a general belief that Graves' orbitopathy (GO) is a "chronic" disease, namely that patients' eyes do not return to how they were before GO appeared. Here, we investigate this issue from both the patient's and the physician's point of view.

STUDY DESIGN

We studied the disappearance of GO, regardless of treatment, in all consecutive patients with a GO history of at least 10 years who came for a follow-up visit over a period of 5 years. Patients underwent an ophthalmological examination and were asked to answer a questionnaire on self-perception related to GO.

RESULTS

We studied 99 consecutive patients with a GO duration ≥10 years. Between the first and the last observation, patients received several types of treatment for their thyroid disease and/or for GO. At the end of follow-up, GO was considered disappeared based on objective criteria in 8 patients (∼8%) and based on subjective criteria in 24 patients (∼24%). When we considered both subjective and objective criteria, only 2 patients (∼2%) had all criteria fulfilled and could be considered as GO-free.

CONCLUSIONS

GO is a chronic disease in the vast majority of patients. Even after a very long time since its onset, complete disappearance is rare, although a minority of patients believe they do not have GO anymore and an even lower proportion do not have relevant GO signs. Our findings have obvious implications in patient management and counseling.