A Prospective Investigation of Graves' Disease and Selenium: Thyroid Hormones, Auto-Antibodies and Self-Rated Symptoms

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.

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.

Graves' disease as a driver of depression: a mechanistic insight

Graves' disease (GD) is characterized by diffuse enlargement and overactivity of the thyroid gland, which may be accompanied by other physical symptoms. Among them, depression can dramatically damage patients' quality of life, yet its prevalence in GD has not received adequate attention. Some studies have established a strong correlation between GD and increased risk of depression, though the data from current study remains limited. The summary of mechanistic insights regarding GD and depression has underpinned possible pathways by which GD contributes to depression. In this review, we first summarized the clinical evidence that supported the increased prevalence of depression by GD. We then concentrated on the mechanistic findings related to the acceleration of depression in the context of GD, as mounting evidence has indicated that GD promotes the development of depression through various mechanisms, including triggering autoimmune responses, inducing hormonal disorders, and influencing the thyroid-gut-microbiome-brain axis. Finally, we briefly presented potential therapeutic approaches to decreasing the risk of depression among patients with GD.

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.

The association between dietary selenium intake and Hashimoto's thyroiditis among US adults: National Health and Nutrition Examination Survey (NHANES), 2007-2012

BACKGROUND

Selenium has been shown to influence the pathological processes and physiological functions of thyroid. Although growing evidence has shown that selenium can improve the treatment of Hashimoto's thyroiditis (HT), there is a need to evaluate the association between dietary selenium intake and HT in a large cross-sectional study. This study explored the association between dietary selenium intake and HT based on the National Health reand Nutrition Examination Survey (NHANES) database (2007-2012).

METHODS

A total of 8756 of 30,442 participants were included in the study. Dietary selenium intake was the independent variable, while HT was the dependent variable. In addition, the relative importance of the selected variables was determined using the XGBoost model. A smooth curve was constructed based on the fully adjusted model to investigate the potential linear relationship between dietary selenium intake and HT. Smooth curves were also constructed to explore the linear/non-linear relationship between dietary selenium intake and thyroid peroxidase antibody (TPOAb)/ thyroglobulin antibody (TgAb).

RESULTS

The mean age of the enrolled participants was 44.35 years (± 20.92). The risk of HT was significantly reduced by a 35% per-unit increase in dietary selenium intake after fully adjusting for covariates according to the model (log2-transformed data; OR 0.65; 95% CI 0.51, 0.83). The XGBoost model revealed that dietary selenium intake was the most important variable associated with Hashimoto's thyroiditis. Dietary selenium intake (Log2-transformed) was negatively correlated with TPOAb levels [- 16.42 (- 22.18, - 10.65), P < 0.0001], while a non-linear relationship was observed between dietary selenium intake and TgAb with an inflection point of 6.58 (95.67 μg, Log2-transformed).

CONCLUSION

Dietary selenium intake is independently and inversely associated with HT risk. Moreover, dietary selenium intake is negatively correlated with TPOAb levels and non-linearly correlated with TGAb levels. Therefore, dietary selenium intake may be a safe and low-cost alternative for the prevention and treatment of HT.

Lack of sufficient evidence to support a positive role of selenium status in depression: a systematic review

CONTEXT

Globally, depression affects more than 322 million people. Studies exploring the relationship between diet and depression have revealed the benefits of certain dietary patterns and micronutrients in attenuating the symptoms of this disorder. Among these micronutrients, selenium stands out because of its multifaceted role in the brain.

OBJECTIVE

To assess the impact of selenium intake and status on symptoms of depression.

DATA SOURCES

A systematic search was performed in databases, including PubMed, Web of Science, EMBASE, PsycINFO, Scopus, and gray literature (on April 6, 2021, updated on January 28, 2022), without restrictions of date, language, or study type.

DATA EXTRACTION

Studies of adults (18-60 y of age) with depression or depressive symptoms were included. Data on selenium biomarkers and/or intake were included. The risk of bias was assessed using the Joanna Briggs Institute checklists.

DATA ANALYSIS

Of the 10 studies included, 2 were cohorts (n = 13 983 and 3735), 3 were cross-sectional (n = 736, 7725, and 200), 1 was case-control (n = 495), and 4 were randomized controlled trials (n = 30, 11, 38, and 63). Several studies have indicated that low selenium intake or concentration may be associated with symptoms of depression. However, this association was inconsistent across the studies included in this systematic review; due to the high heterogeneity, it was not possible to perform meta-analyses. The main contributing factors to the high heterogeneity include the different methodological designs, methods for diagnosing depression, selenium assessment, and clinical conditions.

CONCLUSION

Overall, there is insufficient evidence to support a positive role of selenium status in depression. Studies with more accurate methods and adequate assessment of selenium status are needed to better understand the role of this nutrient in depression.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021220683.

Antagonistic Effect of Selenium on Fumonisin B1 Promotes Neutrophil Extracellular Traps Formation in Chicken Neutrophils

Neutrophils are an important component of the innate immune system, and one of their defense mechanisms, neutrophil extracellular traps (NETs), is a hot topic of the current research. This study explored the effects of fumonisin B1 (FB1) on chicken neutrophil production of NETs and its possible molecular mechanism of action. Scanning electron microscopy and fluorescence microscopy were used to observe morphological changes in neutrophils, and a fluorescence microplate reader was used to detect reactive oxygen species (ROS) and extracellular DNA release from neutrophils. Quantitative PCR (qPCR) and western blot were used to determine the expression levels of selenoproteins. The results indicate that FB1 inhibited the zymosan-induced formation of NETs in chicken neutrophils by preventing ROS burst and histone H3 (H3) and neutrophil elastase (NE) release. Moreover, the mRNA expression levels of glutathione peroxidase (GPX), thioredoxin reductase (TXNRD), and deiodinase (DIO) were downregulated in the FB1 group. The protein expression levels of GPX1, GPX2, GPX3, DIO3, and TXNRD1 were consistent with the changes in their gene expressions, suggesting an abnormal selenoprotein expression in response to the toxic effects of FB1. Conversely, selenium (Se) supplementation reduced the toxic effects of FB1 and restored the NETs formation, indicating that Se can be used as a potential drug to prevent and control FB1 toxicity in livestock farming.

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).

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.

Serum T3 Level and Duration of Minimum Maintenance Dose Therapy Predict Relapse n Methimazole-Treated Graves Disease

Background

Methimazole (MMI) has been advocated as a preferred option for most Graves disease (GD) patients. However, long-term remission after a course of MMI treatment is achieved in only 20% to 40% of patients, depending on the duration of follow-up.

Objective

To evaluate clinical factors for predicting relapse of GD in Thai patients after MMI treatment.

Methods

A retrospective analysis was performed of newly diagnosed patients with GD who achieved remission of hyperthyroid GD after at least 12 months of MMI treatment. Long-term outcomes were assessed and predictive factors of early and late relapse were evaluated.

Results

A total of 443 patients with newly diagnosed GD who were treated with MMI for at least 12 months from 1985 to 2019, and were able to discontinue medication, were studied. The mean age at diagnosis was 37.0 ± 11.4 years and 81.7% were female. Of the 320 patients (72.2%) who achieved initial remission after MMI treatment for 23 months, 106 patients (33.1%) experienced late relapse during the mean follow-up duration of 9.7 years after MMI withdrawal. The remission rates decreased from 36.4% at the first year after stopping MMI to only 20.7% at 10 years. High initial serum triiodothyronine (T3) level and duration of minimum maintenance dose therapy (MMDT) of <6 months were associated with late disease relapse after remission.

Conclusion

The long-term remission rate of Graves hyperthyroidism was achieved in one-fifth of MMI-treated Thai patients. Predictive markers for late relapse included high initial serum T3 level and a duration of MMDT of <6 months.

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.

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.

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.

Reversible Affective Symptoms and Attention Executive Control Network Impairment Following Thyroid Function Normalization in Hyperthyroidism

INTRODUCTION

Affective symptoms and attention impairments are found in patients with hyperthyroidism. Our previous data have revealed that the patients with hyperthyroidism experience impairments of the attention networks, but it remains unclear whether these disorders persist after the treatment of hyperthyroidism.

METHODS

Twenty healthy controls and 25 hyperthyroid patients were recruited and performed the attention network test (ANT) which can simultaneously examine the alertness, orientation and execution control components of the participants. The effect of treatment on affective symptom and attention networks impairments were examined in the patient group after 1-year anti-thyroid medication and reaching euthyroidism for at least 3 months.

RESULTS

Anxiety and depression scores of patients with hyperthyroidism were significantly higher than those of the healthy control group. The patients with hyperthyroidism had impairments of the alerting and executive control networks. Meanwhile, the score of HAMA correlated significantly with thyroid hormone and TSH levels, and there was a negative significant correlation between the score of HAMD and TSH level in all subjects. There was a positive correlation between the value of the executive control network and thyroid hormones' levels in all subjects and in the hyperthyroidism group. Anxiety and depression symptoms were improved with methimazole treatment after euthyroidism was reached. The value of the executive control network no longer differed from that of healthy controls, but deficits in the alerting network of hyperthyroidism still persisted after treatment.

CONCLUSION

The patients with hyperthyroidism existed affective symptoms and attention networks impairments. Affective symptoms and attention executive control network impairment were improved following thyroid function normalization in hyperthyroidism.

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.

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.

Serum Trace Elements Profile in Graves' Disease Patients with or without Orbitopathy in Northeast China

Objective

The purpose of the present study was to investigate serum trace elements in Graves' disease (GD) patients with or without orbitopathy in Northeast China.

Methods

Patients with newly diagnosed Graves' disease (HyGD) (n = 66), GD patients with euthyroid status or subclinical thyroidism after treatment (EUGD) (n = 55), GO patients with euthyroid status or subclinical thyroidism after treatment (GO) (n = 57), and normal controls (NC) (n = 66) were enrolled in this study. Serum trace elements were measured with ICP-MS.

Results

Serum selenium (Se) levels in EUGD group (median: 7.53 µg/dL), HyGD group (median: 6.76 µg/dL), and GO group (median: 7.40 µg/dL) were significantly lower than those in NC group (median: 9.20 µg/dL, all P < 0.01). Serum copper (Cu) levels in GO group (median: 95.93 µg/dL) were significantly lower than those in the NC group (median: 113.59 µg/dL, P = 0.015). After being adjusted for multivariables, thyroid-specific antibodies grade was associated with low Se levels. Hyperthyroidism and thyroid-specific antibodies grade were associated with high Cu levels. In addition, orbitopathy was associated with low Cu levels.

Conclusions

Thyroid autoimmunity was associated with low Se levels. Hyperthyroidism and thyroid autoimmunity may be associated with relatively high serum Cu levels. Alternatively, ophthalmopathy may be related to low serum Cu levels.

Electrochemical versus Enzymatic in Vitro Oxidations of 6-propyl-2-thiouracil: Identification, Detection, and Characterization of Metabolites

6-Propylthiouracil, PTU, is a well-known antithyroid drug that has been the mainstay of treatment of Graves' disease. It is, however, also associated with liver toxicity and idiosyncratic toxicity. These toxicities are generally associated with metabolites derived from its bioactivation. In this manuscript, bioactivation of PTU was studied via two separate techniques: electrochemical oxidation and through the use of human liver microsomes. The aim of this work was to compare the bioactivation products of these two techniques. The electrochemical technique was studied online with a mass spectrometer, EC/ESI/MS. The microsomal oxidations were studied in tandem with liquid chromatography. The EC/ESI/MS technique was devoid of the normal reducing biological matrix prevalent in microsomal incubations. The predominant product at 400 mV was the dimeric PTU species with negligible formation of other metabolites. At higher potentials, complete desulfurization of PTU was observed with formation of sulfate. No sulfonic acid was observed, suggesting that the cleavage of the C-S bond was effected at the sulfinic acid stage, releasing a highly reducing sulfur species which is known to give rise to genotoxicity. The microsomal oxidations, surprisingly, showed formation of the unstable sulfenic acid, the S-oxide. Further incubation showed both the sulfinic and sulfonic acids. None of the systems showed any adducts with nucleophiles such as glutathione, showing that none of the reactive metabolites were stable enough to be adducted to nucleophiles in both the biological matrix and the electrochemical oxidizing environment.

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.

A case-control study of selenoprotein genes polymorphisms and autoimmune thyroid diseases in a Chinese population

Background

Selenium is an essential trace and there is a high selenium concentration in the thyroid gland. Selenium deficiency may impair the thyroid function. The aim of this study was to investigate the association between three selenoprotein genes polymorphisms and autoimmune thyroid diseases.

Methods

We genotyped six single-nucleotide polymorphisms (SNPs), rs6865453 in selenoprotein P gene (SELENOP), rs713041 rs2074451 rs3746165 in glutathione peroxidase 4 gene (GPX4) and rs28665122 and rs7178239 in selenoprotein S gene (SELENOS) by MassARRAY system using the chip-based matrix-assisted laser desorption ionization time-of-flight mass spectrometry technology in 1060 patients with autoimmune thyroid diseases and 938 healthy controls.

Results

Major alleles in rs6865453 of SELENOP, rs713041, rs2074451, rs3746165 of GPX4 decreased while the major allele C in rs28665122 of SELENOS increased in AITD patients than in the control. The allele C and genotype CC in rs7178239 of SELENOS showed different trend in GD and HT patients when compared with the control. All the distribution difference showed nonsignificant. Analysis according to clinical features including ophthalmopathy, hypothyroidism and family history came out to be negative either.

Conclusions

Our findings suggest non-association between three selenoprotein genes and AITD, conflicting to the positive result in another population. Different selenium nutrition status in different populations may contribute to conflicting results, the contribution of genetic variants in AITD mechanism may be another reason.

Antithyroid Drug Therapy for Graves' Disease and Implications for Recurrence

Graves' disease (GD) is the most common cause of hyperthyroidism worldwide. Current therapeutic options for GD include antithyroid drugs (ATD), radioactive iodine, and thyroidectomy. ATD treatment is generally well accepted by patients and clinicians due to some advantages including normalizing thyroid function in a short time, hardly causing hypothyroidism, and ameliorating immune disorder while avoiding radiation exposure and invasive procedures. However, the relatively high recurrence rate is a major concern for ATD treatment, which is associated with multiple influencing factors like clinical characteristics, treatment strategies, and genetic and environmental factors. Of these influencing factors, some are modifiable but some are nonmodifiable. The recurrence risk can be reduced by adjusting the modifiable factors as much as possible. The titration regimen for 12-18 months is the optimal strategy of ATD. Levothyroxine administration after successful ATD treatment was not recommended. The addition of immunosuppressive drugs might be helpful to decrease the recurrence rate of GD patients after ATD withdrawal, whereas further studies are needed to address the safety and efficacy. This paper reviewed the current knowledge of ATD treatment and mainly focused on influencing factors for recurrence in GD patients with ATD treatment.

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

OBJECTIVE

In spite of previous conflicting results, an adjuvant role of selenium in the treatment of Graves' disease (GD) hyperthyroidism has been proposed. To address this issue, a randomized clinical trial was carried out aimed at investigating whether selenium is beneficial on the short-term control of GD hyperthyroidism treated with methimazole (MMI).

METHODS

Thirty newly diagnosed hyperthyroid GD patients were randomly assigned to treatment with: (i) MMI or (ii) MMI plus selenium. Primary outcomes were: control of hyperthyroidism and clinical and biochemical manifestations of hyperthyroidism [heart rate, cholesterol, sex hormone-binding globulin (SHBG), hyperthyroidism symptoms] at 90 days.

RESULTS

Baseline features of the two groups did not differ. Serum selenium at baseline was similar in the two groups and within the recommended range to define selenium sufficiency. Selenium increased with treatment in the MMI-selenium group and became significantly higher than in the MMI group. Serum malondialdehyde, a marker of oxidative stress, was similar in the two groups and decreased significantly with treatment, with no difference between groups. Administration of MMI was followed by a reduction of FT₃ and FT₄, with no difference between groups. Heart rate, SHBG and symptoms of hyperthyroidism decreased, whereas total cholesterol increased in both groups with no difference between groups.

CONCLUSIONS

Our study, carried out in a selenium-sufficient cohort of GD patients, failed to show an adjuvant role of selenium in the short-term control of hyperthyroidism. However, selenium might be beneficial in patients from selenium-deficient areas, as well as in the long-term outcome of antithyroid treatment.

Current trends in antithyroid drug treatment of Graves' disease

INTRODUCTION

Graves' hyperthyroidism is associated with significant morbidity and mortality risk. The thionamides, methimazole, its pro-drug derivative carbimazole, and propylthiouracil, remain a cornerstone of management. Yet despite decades of use, optimal strategies for maximising treatment response and curtailing adverse effect risk remains uncertain.

AREAS COVERED

We reviewed the current literature on the evidence based medical management of Graves' disease. Specifically, we evaluated current approaches to the use of thionamides, adjunctive therapies, and potential novel agents for controlling Graves' hyperthyroidism.

EXPERT OPINION

Primary medical therapy is successful in less than 50% of cases and so careful selection of patients for medical treatment based on a combination of pathological and pragmatic considerations is essential. Carbimazole or methimazole is the treatment of choice in the non-pregnant population driven by its more favourable pharmacokinetic and adverse effect profile over propylthiouracil. In pregnancy the choice of treatment is less straightforward and an approach that minimises undue fetal exposure to all thionamides should be adopted. Additional data is needed on the value of adjunctive therapies including potassium perchlorate, iodides, glucocorticoids, lithium, and cholestyramine. Novel agents directed against pathogenetic targets including TSH receptor blocking monoclonal antibodies and small molecule antagonists may hold promise for the future.