Influence of short-term selenium supplementation on the natural course of Hashimoto's thyroiditis: clinical results of a blinded placebo-controlled randomized prospective trial

Selenium nutritional status and thyroid dysfunction

Selenium(Se) is an essential micronutrient for several immune and regulatory functions in the body. In thyroid tissue, Se contributes to the antioxidant system and is a crucial component of deiodinases, which are selenoproteins that participate in thyroid hormone metabolism. Additionally, this micronutrient exerts a significant impact on thyroid pathophysiology, as low levels of Se lead to reduced activity of glutathione peroxidase, a selenoprotein involved in antioxidative processes, thereby resulting in increased oxidative stress and damage to thyroid tissue. Selenium deficiency (SeD) can cause growth retardation and reproductive failure; in women and children, it may result in Keshan's disease and Kashin-Beck's disease. Research has shown an inverse correlation between Se serum levels and autoimmune thyroiditis in areas with mild SeD. In Graves' disease, Se supplementation has been linked to faster achievement of euthyroidism as well as improvements in quality of life, lessened orbital involvement, and slower ocular progression of the disease. Furthermore, several studies suggest an association between serum SeD and the development of thyroid cancer. Maintaining physiological Se concentrations appears to be related to the prevention of thyroid disease, although current data are insufficient to conclusively support or refute the efficacy of supplementation. Through this narrative review, we aim to present the latest information on the role of selenium in thyroid pathophysiology. To identify relevant literature, specific search strategies were employed in the electronic databases PubMed, Lilacs, and SciELO.

Selenium supplementation in thyroid eye disease: an updated review from a clinical ophthalmic perspective

Thyroid eye disease (TED) consists of a spectrum of autoimmune orbital pathology that threatens patients' quality of life and vision. Research suggests that oxidative stress plays a role in both the thyroid gland and orbit. Selenium has been proposed as a potential therapeutic adjunct given its role in thyroid physiology and antioxidant metabolism. Furthermore, selenium status has been linked to multiple pathological thyroid states. Despite the preponderance of evidence demonstrating a role for selenium in thyroid disease, limited research exists highlighting its role in TED specifically. This review summarizes the pathophysiology and role of selenium in thyroid eye disease (TED) and the current body of evidence including in vitro and in vivo studies highlighting the role for supplementation in clinical ophthalmic practice. Notably, relatively lower selenium levels have been shown to have a modest correlation with severity of thyroid eye disease. Selenium supplementation has shown some benefit in patients with mild Graves' Orbitopathy in European populations presumed deficient. Despite the preponderance of evidence demonstrating a role for selenium in thyroid disease, limited data is available to conclusively expand its role in TED outside of a 6-month course of supplementation in selenium deficient or relatively deficient populations. Data subject to geographic and population differences in selenium levels limits the generalizability of supplementation in TED. Despite mechanistic evidence of its antioxidant effects in TED beyond the advantages of thyroid disease in general, the benefits of selenium supplementation should be interrogated further and contextually tailored in both clinical and research formats for ophthalmic practice.

Vitamin D, selenium, and antidiabetic drugs in the treatment of type 2 diabetes mellitus with Hashimoto's thyroiditis

BACKGROUND

Diabetes and thyroiditis are closely related. They occur in combination and cause significant damage to the body. There is no clear treatment for type-2 diabetes mellitus (T2DM) with Hashimoto's thyroiditis (HT). While single symptomatic drug treatment of the two diseases is less effective, combined drug treatment may improve efficacy.

AIM

To investigate the effect of a combination of vitamin D, selenium, and hypo-glycemic agents in T2DM with HT.

METHODS

This retrospective study included 150 patients with T2DM and HT treated at The Central Hospital of Shaoyang from March 2020 to February 2023. Fifty patients were assigned to the control group, test group A, and test group B according to different treatment methods. The control group received low-iodine diet guidance and hypoglycemic drug treatment. Test group A received the control treatment plus vitamin D treatment. Test group B received the group A treatment plus selenium. Blood levels of markers of thyroid function [free T3 (FT3), thyroid stimulating hormone (TSH), free T4 (FT4)], autoantibodies [thyroid peroxidase antibody (TPOAB) and thyroid globulin antibody (TGAB)], blood lipid index [low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triacylglycerol (TG)], blood glucose index [fasting blood glucose (FBG), and hemoglobin A1c (HbA1c)] were measured pre-treatment and 3 and 6 months after treatment. The relationships between serum 25-hydroxyvitamin D3 [25 (OH) D3] level and each of these indices were analyzed.

RESULTS

The levels of 25 (OH) D3, FT3, FT4, and LDL-C increased in the order of the control group, test group A, and test group B (all P < 0.05). The TPOAB, TGAB, TC, TG, FBG, HbA1c, and TSH levels increased in the order of test groups B, A, and the control group (all P < 0.05). All the above indices were compared after 3 and 6 months of treatment. Pre-treatment, there was no divergence in serum 25 (OH) D3 level, thyroid function-related indexes, autoantibodies level, blood glucose, and blood lipid index between the control group, test groups A and B (all P > 0.05). The 25 (OH) D3 levels in test groups A and B were negatively correlated with FT4 and TGAB (all P < 0.05).

CONCLUSION

The combination drug treatment for T2DM with HT significantly improved thyroid function, autoantibody, and blood glucose and lipid levels.

Emerging Insights and Global Trends in the Relationship between Selenium and Thyroid Diseases: A Bibliometric Analysis

OBJECTIVE

Selenium, a significant trace element needed by the human body, is closely related to thyroid. Therefore, this study aimed to explore the status of selenium and thyroid diseases, analyze emerging insights, and predict future trends.

METHODS

Literature on selenium and thyroid included in the core database of Web of Science from January 1992 to October 2022 was retrieved. CiteSpace and VOSviewer software were used for visual analysis in terms of publication, author, country, institution, co-citation, and keywords.

RESULTS

A total of 1,142 works of literature were included after the screening, and the annual publication showed a fluctuating upward trend. The country and the institution with the highest publication volume were the United States and Charité Universitätsmedizin Berlin, respectively. In terms of authors, Schomburg L has formed a cooperative network and has published the largest number of papers and made great contributions in this field. The biggest cluster of keywords was trace elements, and the hot keywords in recent years were oxidative stress, Hashimoto's thyroiditis, cadmium, copper, etc. Conclusion: This paper analyzes the current status, insights, and trends of the studies on selenium and thyroid diseases by the method of bibliometrics and delivers ideas and methods for subsequent research in this field. The therapeutic effect of selenium on Hashimoto's thyroiditis is controversial and needs further research, and oxidative stress is also a research hotspot in this field. The crossstudy of multiple trace elements and diseases may be the development trend in the future.

Do Dietary Supplements Affect Inflammation, Oxidative Stress, and Antioxidant Status in Adults with Hypothyroidism or Hashimoto's Disease?-A Systematic Review of Controlled Trials

This systematic review aims to summarise the results of controlled trials on dietary supplements (DS) usage and inflammation, oxidative stress, antioxidant status, and thyroid parameter improvement in hypothyroidism (HT)/Hashimoto's thyroiditis (AIT) patients. The study protocol was registered with PROSPERO (no. CRD42022365149). A comprehensive search of the PubMed, Scopus, and Web of Science databases resulted in the identification of nineteen randomised controlled trials and three non-randomised studies for the review; three studies examined the effect of supplementation with vitamin D, twelve studies-with selenium, and seven studies-with other DS. Based on very limited evidence, the lack of influence of vitamin D supplementation on inflammatory parameters was found, while no studies have examined oxidative stress and antioxidant status parameters, and only one provided results for a single thyroid parameter after an intervention. Some evidence was found proving that selenium supplementation may decrease inflammation and improve thyroid parameters, but reaching a conclusion about its influence on oxidative stress and antioxidant status is not possible because of the insufficient number of studies. Additionally, due to examining other DS (e.g., multicomponent, Nigella sativa, and genistein) only in single studies, conclusions cannot be drawn. Further long-term, high-quality randomised controlled trials are necessary to better understand the influence of DS on inflammation, oxidative stress, and antioxidant status, as well as their potential to improve thyroid gland function in HT/AIT patients.

Autoimmune Thyroid Disorders: The Mediterranean Diet as a Protective Choice

Autoimmune thyroid diseases are on the rise worldwide, and such a rapid increase is mainly driven by environmental factors related to changed lifestyles in "modern" societies. In this context, diet seems to play a crucial role. An unhealthy high-energy diet, rich in animal fat and proteins, salt and refined sugars (the so-called "Western diet") negatively influences the risk of autoimmunity by altering the immune balance and the gut microbiota composition, enhancing oxidative stress and promoting inflammation. In contrast, the Mediterranean diet represents a unique model of healthy eating, characterized by a high intake of food from vegetable sources, a low consumption of saturated fats in favor of unsaturated fats (mainly, olive oil), a moderate consumption of fish (typically, the small oily fishes) and dairy products, as well as a moderate consumption of wine at meals, and a low intake of meat. Thanks to its nutritional components, the Mediterranean Diet positively influences immune system function, gut microbiota composition, and redox homeostasis, exerting anti-oxidants, anti-inflammatory, and immunomodulatory effects. The present review was aimed at exploring the existing knowledge on the correlations between dietary habits and thyroid autoimmunity, to evaluate the role of the Mediterranean diet as a protective model.

Chemokines in thyroid autoimmunity

The chemokine receptor CXCR3 and its chemokines CXCL9, CXCL10, and CXCL11 are involved in the pathogenesis of autoimmune diseases. Th1 lymphocytes are recruited by Th1 chemokines, secreted by damaged cells. In inflamed tissues, the attracted Th1 lymphocytes induce the IFN-gamma and TNF-alpha release, that stimulates the secretion of Th1 chemokines, initiating and reiterating an amplification feedback loop. Autoimmune thyroid disorders (AITD) are the most recurrent autoimmune diseases, including Graves' disease (GD) and autoimmune thyroiditis, clinically defined by thyrotoxicosis and hypothyroidism, respectively. Graves' ophthalmopathy is one of GD extrathyroidal manifestations, occurring in ~30-50% of GD patients. In the early phase of AITD, the Th1 immune response is prevalent, and a following switch to a Th2 immune response has been shown in the late, inactive, phase. The reviewed data underline the importance of chemokines in thyroid autoimmunity and suggest CXCR3-receptor and its chemokines as potential targets of novel drugs for these disorders.

Emerging trends and hot spots in autoimmune thyroiditis research from 2000 to 2022: A bibliometric analysis

Background

Autoimmune thyroiditis (AIT) is the most common autoimmune disease, affecting 3-5% patients worldwide. In recent years, approximately 200 articles on AIT have been published annually in various journals. However, to date, no article has systematically assessed the related literature. Therefore, we conducted a bibliometric analysis on AIT to reveal the dynamic scientific developments and help researchers gain a global perspective while exploring the hotspots and development trends.

Methods

AIT-related articles and reviews from 2000 to 2022 were retrieved from the Web of Science Core Collection (WoSCC). The following search terms were used to extract document data: TS= (“ autoimmune thyroiditi*”) OR TI= (“chronic lymphocytic thyroiditi*”) OR TI=(hashimoto*) OR TI= (“postpartum thyroiditis”). We selected articles and reviews published in English from 2000 to 2022. Three software programs (VOSviewer, CiteSpace, Pajek) were employed to analyze the contribution and co-occurrence relationships of different references, countries/regions, institutes, journals and also keywords in this field.

Results

This scientometric study included 2290 English papers published in 723 journals with 39661 co-cited references from 561 institutions in 120 countries/regions. Based on the reference and keyword analysis, researchers used to focus on “apoptosis”, “insulin resistance”, “encephalopathy”, “IFN-γ” related to AIT during the past 20 years. However, with the development of other novel directions such as “papillary thyroid cancer” (2018-2022), “Vitamin D” (2016-2022), “oxidative stress” (2018-2022), “polymorphism” (2019-2022) and “association” (2020-2022), researchers are more interested in the relationship between papillary thyroid carcinoma and AIT, the effect of vitamin D supplementation on AIT, the oxidative stress in thyroid disease as well as the influence of polymorphism.

Conclusion

Bibliometric analysis of the outputs of AIT shows an overview of the current status of the research on AIT. The associations between papillary thyroid carcinoma, vitamin D, oxidative stress, polymorphism and AIT are major research frontiers. However, further research and collaboration are still required worldwide. Our findings can help researchers grasp the research status of AIT and quickly determine new directions for future research.

Assessment of the Effect of Selenium Supplementation on Production of Selected Cytokines in Women with Hashimoto’s Thyroiditis

The impact of selenium on the course of Hashimoto’s thyroiditis (HT) was mainly assessed by monitoring the titer of antithyroid autoantibodies in most of the studies conducted hitherto. On the other hand, the imbalance in activity of T cells such as Th1, Th2, Th17, and Treg may be relevant in the pathogenesis of this disease. Hence, the assessment of changes in the secretion of cytokines by these cells during selenium supplementation in patients with HT seems to be an important issue and was the main goal of this study. A further aim was to search for correlations among these cytokines, as well as markers of thyroid function, selenium/iodine status in the body, and other biochemical parameters. The group of 29 women with newly diagnosed Hashimoto’s thyroiditis was supplemented with selenium in a dose of 100 µg/day for 6 months. Immunological parameters: interferon γ, tumor necrosis factor α, chemokine CXCL10, interleukin 4, interleukin 1β, interleukin 17, transforming growth factor β, and C-reactive protein, as well as selenium status parameters were determined in serum twice, i.e., before and after supplementation. Selenium supplementation was associated with a change in the production of two cytokines: interferon γ and interleukin 1β, for which a decrease and an increase in concentration were observed, respectively. The partial least squares (PLS) model revealed the presence of many relevant correlations among analyzed parameters. The stage of HT development, degree of thyroid dysfunction, and selenium supplementation of diet are interdependent factors which shape the profile of some cytokines secreted by cells participating in the autoimmunity process.

Metabolic Characteristics of Hashimoto's Thyroiditis Patients and the Role of Microelements and Diet in the Disease Management-An Overview

Hashimoto’s thyroiditis (HT) is the most common autoimmune disease and the leading cause of hypothyroidism, in which damage to the thyroid gland occurs due to the infiltration of lymphocytes. It is characterized by increased levels of antibodies against thyroid peroxidase and thyroglobulin. In this review, we present the metabolic profile, the effectiveness of micronutrient supplementation and the impact of dietary management in patients with HT. For this current literature review, the databases PubMed, Cochrane, Medline and Embase were reviewed from the last ten years until March 2022. This article provides a comprehensive overview of recent randomized controlled trials, meta-analyses, and clinical trials. Many patients with HT, even in the euthyroid state, have excess body weight, metabolic disorders, and reduced quality of life. Due to frequent concomitant nutritional deficiencies, the role of vitamin D, iodine, selenium, magnesium, iron and vitamin B12 is currently debated. Several studies have underlined the benefits of vitamin D and selenium supplementation. There is still no specific diet recommended for patients with HT, but a protective effect of an anti-inflammatory diet rich in vitamins and minerals and low in animal foods has been suggested. There is insufficient evidence to support a gluten-free diet for all HT patients. Pharmacotherapy, along with appropriate nutrition and supplementation, are important elements of medical care for patients with HT. The abovementioned factors may decrease autoantibody levels, improve thyroid function, slow down the inflammatory process, maintain proper body weight, relieve symptoms, and prevent nutritional deficiencies and the development of metabolic disorders in patients with HT.

Selenium Supplementation in Pregnant Women with Autoimmune Thyroiditis: A Practical Approach

Selenium (Se) is an essential trace element with antioxidant and anti-inflammatory properties and a pivotal role in thyroid metabolism. Ensuring a sufficient Se supply is possible via a balanced, wholesome diet; however, Se content in foods may be different throughout geographical areas. Se supplementation is expected to improve inflammatory status in patients with autoimmune thyroiditis, especially in those with high activity, and has been demonstrated as effective in reducing the thyroid peroxidase antibodies titer. Se status seems to affect thyroid function in pregnancy, which prompts the potential role of Se supplementation in such patients. Few clinical trials have investigated the effectiveness of Se supplementation in pregnant women with thyroiditis, and their results suggest the safety and effectiveness of this element in reducing autoantibody levels and preventing postpartum thyroiditis development, although limited. Hence, more robust evidence is needed to confirm these data. The current study aims to summarize published data on the relationship between Se and thyroid status in pregnant women with thyroiditis and the potential use of Se. Moreover, an algorithm for Se supplementation is proposed for pregnant women with thyroiditis to help endocrinologists in daily clinical practice to consider Se status.

Effect of Selenium-Enriched Yeast Supplementation on Serum Thyroid-Stimulating Hormone and Anti-Thyroid Peroxidase Antibody Levels in Subclinical Hypothyroidism: Randomized Controlled Trial

Background

In the subclinical hypothyroidism, T4 or T3 levels are normal and thyroid-stimulating hormone (TSH) is slightly high. Selenium deficiency can lead to thyroid dysfunction. The present study aims to investigate the effect of selenium supplementation on the thyroid hormone and anti-thyroid peroxidase antibody (anti-TPO AB) levels.

Materials and Methods

In this double-blinded, randomized, placebo-controlled clinical trial, 42 patients with subclinical hypothyroidism were randomly assigned to receive 200 μg selenium or placebo for 8 weeks. In the both groups, the serum TSH and anti-TPO antibody levels were measured and assessed before and after the intervention.

Results

After the interventions, the mean serum TSH reduction in the intervention and placebo groups was -10.98 ± 33.31 and -3.20 ± 38.36, respectively, which were not statistically significant. However, the mean serum anti-TPO Ab concentration increased in the intervention and placebo groups (109.81 ± 51.49% vs. 173.17 ± 96.26%), between which the difference was not statistically significant (P >0.05) despite a slight increase in the mean anti-TPO level in the intervention group.

Conclusion

The results of the current study indicated that selenium supplementation has no significant effect on serum anti-TPO Ab and TSH levels in the patients with subclinical hypothyroidism. Studies with larger sample size and with different doses of selenium are needed to reach more precise results.

Precision Medicine in Autoimmune Thyroiditis and Hypothyroidism

Autoimmune thyroid diseases (AITD) are T-cell-mediated organ specific autoimmune disorders, deriving from an altered response of the immune system that leads to the immune attack to the thyroid. Hashimoto’s thyroiditis (HT) and Graves’ disease (GD) are the two principal AITD clinical presentations. Hypothyroidism and thyrotoxicosis are, respectively, the clinical hallmarks of HT and GD. Patients with autoimmune thyroiditis are treated daily with synthetic L-thyroxine (L-T4) at the dose of 1.5–1.7 μg/kg. Various L-T4 formulations are commercially available (tablet, liquid solution, or soft gel capsule). L-T4 in tablets is generally prescribed to treat hypothyroidism, whereas the liquid formulation, or soft gel capsules, can be administered in hypothyroid patients in case of malabsorption or in patients in therapy with drugs interfering with L-T4 absorption. Furthermore, myoinositol has a crucial role in thyroid autoimmunity and function. Clinical studies reported a significant decline in TSH and antithyroid autoantibodies levels after treatment with myoinositol + selenium in patients with subclinical hypothyroidism and autoimmune thyroiditis. Moreover, thyroidectomy can be rarely recommended in patients with autoimmune thyroiditis, with cosmetic reasons for a goiter, or with important signs or symptoms of local compression, or nodular disease with a “suspicious” cytology for malignancy. Furthermore, a recent randomized trial suggested that total thyroidectomy can improve quality of life and fatigue, while medical therapy did not. In this review, we overview currently available evidence in personalized medicine in patients with autoimmune thyroiditis and hypothyroidism. Further research is needed in larger population to investigate the effect of these new treatments on quality of life.

Wpływ suplementacji diety selenem na przebieg autoimmunologicznego zapalenia tarczycy – przegląd badań klinicznych przeprowadzonych w populacji europejskiej

Wiele obserwacji wskazuje na zależność między zmniejszonymi zasobami selenowymi organizmu a różnymi schorzeniami tarczycy, w tym także autoimmunologicznym zapaleniem tarczycy (AZT). W większości prac poświęconych temu zagadnieniu zmiana stężenia przeciwciał anty-TPO była główną miarą oceny skuteczności suplementacji selenem (Se) diety pacjentów z AZT. Stężenie przeciwciał anty-TPO ma wpływ na intensywność nacieków limfocytarnych w gruczole tarczowym i stopień jego uszkodzenia, dlatego zmniejszenie ich stężenia w wyniku zwiększonego spożycia Se może się przyczynić do skuteczniejszego leczenia AZT. W części prac omówionych w artykule ewaluacja immunoregulacyjnego działania Se w przebiegu AZT została rozpatrzona w odniesieniu do szerszego zakresu parametrów biochemicznych i immunologicznych (głównie dotyczy to zmian w wytwarzaniu cytokin i chemokin). Wielu autorów potwierdziło wpływ Se na zmniejszanie stężenia przeciwciał anty-TPO, jednak wyniki wszystkich prac nie są jednoznaczne. Przyczyną rozbieżności może być odmienny stopień wysycenia tarczycy Se i jodem w różnych grupach pacjentów, różny stopień zaawansowania choroby, różne dawki Se podawanego pacjentom, stosowanie lub niestosowanie jednoczesnej terapii L-tyroksyną oraz polimorfizmy pojedynczych nukleotydów (SNP) występujące w genach kodujących poszczególne selenobiałka.

Na podstawie dostępnej literatury można wnioskować, iż zagadnienie dotyczące roli Se w AZT jest nadal słabo poznane. Istnieje potrzeba kontynuowania badań oceniających wpływ suplementacji diety Se na przebieg tej choroby, które powinny obejmować poza anty-TPO inne parametry kliniczne. Dopiero wyniki tak szeroko ujętych badań mogą być pomocne w formułowaniu nowych wytycznych dotyczących wspomagania leczenia przez odpowiednią modyfikację diety z uwzględnieniem suplementacji Se.

Positive effects of selenium supplementation in women with newly diagnosed Hashimoto's thyroiditis in an area with low selenium status

OBJECTIVE

Autoimmune thyroid diseases, including Hashimoto's thyroiditis, are the most common ones among autoimmune diseases. The reported effects of selenium supplementation on the course of Hashimoto's thyroiditis are not consistent. It is therefore important to continue this line of research.

DESIGN

The participants received selenium in the form of sodium selenite(IV) at a dose of 100 µg/day for 6 months.

PATIENTS

Newly diagnosed and previously untreated Hashimoto's thyroiditis with euthyroidism or subclinical hypothyroidism. A total of 36 patients (aged 20 to 52 years) qualified for this study, of whom 29 women were successfully enrolled and completed the intervention.

MEASUREMENTS

Both before and after supplementation the following parameters in serum were tested: anti-thyroid peroxidase antibodies, thyroid function indicators, selenium as well as antioxidant status parameters and other biochemical parameters (lipid profile, glucose). Iodine supply and subjective assessment of physical and psychological health were also monitored.

RESULTS

Selenium supplementation decreased significantly level of anti-thyroid peroxidase antibodies what might have had a stabilizing effect on thyroid function, as values of thyroid parameters were within normal range before and at the end of the study. Mean level of selenium among patients was not different to healthy people in Poland. Median of ioduria was within normal range.

CONCLUSIONS

The study shows a potential way of protective effect of selenium in limiting development of overt hypothyroidism. The increase in the concentrations of Se and SELENOP in the serum of patients verifies successful supplementation and good compliance, but did not affect the antioxidant status parameters measured.

Insufficient evidence to support the clinical efficacy of selenium supplementation for patients with chronic autoimmune thyroiditis

BACKGROUND

This study critically reappraises the documentation on the clinical efficacy of selenium supplementation in chronic autoimmune thyroiditis (AIT) with the goal of improving the normalization of the treatment of this disease.

METHODS

A literature search was performed in the Medline, Embase, and Cochrane Library databases. Twenty-three trials conducted in adults with AIT comparing the efficacy of selenium with or without levothyroxine (LT4) versus placebo and/or LT4 were eligible. The assessed outcomes were primarily pooled using a random- or fixed effects model based on the results of the heterogeneity test. The quality of evidence was assessed per outcome.

RESULTS

In LT4-treated populations, patients receiving selenium demonstrated lower thyroid peroxidase antibody (TPOAb) levels at 3 months (mean difference [MD], -236.88; 95% confidence interval [CI], -353.35 to -120.41; p < 0.0001), 6 months (MD, -407.17; 95% CI, -623.60 to -190.73; p = 0.0002), and 12 months (MD, -327.03; 95% CI, -613.78 to -40.28; p = 0.0254), while thyroglobulin antibody (TgAb) levels only decreased at 12 months. In non-LT4-treated population, the selenium group demonstrated significantly lower TPOAb levels after 3 months (MD, -203.07; 95% CI, -395.44 to -10.70; p = 0.0385) and 6 months (MD, -322.27; 95% CI, -597.50 to -47.04; p = 0.0217) but not after 12 months, while TgAb levels only decreased at 3 months. There was no significant change in thyroid stimulating hormone (TSH) levels. Lower thyroid echogenicity was observed in all patients receiving selenium at 3, 6, and 12 months. However, these participants had a significantly higher risk of reported adverse effects.

CONCLUSIONS

Current evidence does not justify the emerging use of selenium supplementation in the treatment of AIT, despite it resulting in a decrease in autoantibody levels.

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.

Acupuncture for Hashimoto thyroiditis: study protocol for a randomized controlled trial

BACKGROUND

The incidence rate of Hashimoto thyroiditis (HT) has gradually increased in recent years. There has been no specific etiological treatment for HT. Even though with normal level of thyroid hormone, the patients may still suffer from various clinical symptoms, such as anterior neck discomfort, fatigue, and mood swings, which seriously impair their quality of life. Acupuncture has long been used in the treatment of thyroid diseases, but there has been no related standardized clinical study as of today. This study aims to assess the feasibility, efficacy, and safety of acupuncture for HT.

METHODS

This is a randomized, black-controlled assessor-blinded pilot trial. A total of 60 patients will be recruited and divided into the experimental group (n = 30) or the control group (n = 30). The experimental group will undergo acupuncture therapy (penetration needling of Hand-Yangming meridian, PNHM) for 16 weeks, followed by a 16-week follow-up period, and the control group will first go through an observation period for 16 weeks, followed by a 16-week compensation PNHM therapy. The primary outcome will be the change of the concentrations of anti-thyroperoxidase antibodies (TPOAb), antithyroglobulin antibodies (TgAb), and thyroid hormone, including total thyroxine (FT₄), free thyroxine (FT₃), and thyroid-stimulating hormone (TSH). The secondary outcome measurements include the thyroid-related quality of life questionnaire short-form (ThyPRO-39), The Mos 36-item Short Form Health Survey (SF-36), and Hospital Anxiety and Depression Scale (HAD). Data collection will be performed before the start of the study (the baseline assessment) and at weeks 8, 16, 24, and 32.

DISCUSSION

The study is designed to assess the feasibility and effectiveness of PNHM in reducing the thyroid antibody level and improving the quality of life of HT patients with hypothyroidism or subclinical hypothyroidism. Results of this trial will assist further analyses on whether the acupuncture treatment can alleviate symptoms for patients with HT.

TRIAL REGISTRATION

Acupuncture-Moxibustion Clinical Trial Registry AMCTR-IOR-19000308 ( ChiCTR1900026830 ). Registered on 23 October 2019.

An Overview of the NF-kB mechanism of pathophysiology in rheumatoid arthritis, investigation of the NF-kB ligand RANKL and related nutritional interventions

Nuclear Factor Kappa-Β (NF-kB) is recognized as one of the main inflammatory pathways in the Autoimmune Disease (AD) Rheumatoid Arthritis (RA), which exhibits high levels of inflammatory cytokines such as IL-1, TNFa and IL-6 linked to bone erosion and disease progression. NF-kB is also the most studied pathophysiological mechanism in RA, however, over the last few decades, a more recently discovered Receptor Activator of Nuclear Factor Kappa-Β Ligand (RANKL), also linked to NF-kB activation and bone erosion, has been the topic of interest for research in the area of AD management. As the non-discriminative long term suppression of the NF-kB pathway by pharmacological agents in the management of RA has been linked with a number of side effects and with the discovery of the RANKL mechanism, which may present a more targeted approach to the management of the AD, there has been renewed interest in research on the potential impact of nutritional interventions influencing the NF-kB pathway, RANKL as well as RA disease outcomes. Existing research highlights the potential utility of nutrients such as Omega 3 and Vitamin D, which may lower NF-kB activation in RA. There is, however, a gap in the knowledge of the effects of nutritional interventions on pathophysiological mechanisms contributing to RA and a more robust systematic analysis of whether nutrients or specific vitamins can have an effect on the NF-kB and RANKL main drivers of pathology in RA. Findings from this study suggest the potential of Vitamin D supplementation in lowering the levels of RANKL and related markers/cytokines such as Th17 cell levels, OPG/RANKL ratio and CXCL10 pathway, which may present as a viable nutrition intervention for the management of RA. The methodology of this review involved a Systematic Search of the Literature with a Critical Appraisal of papers. It incorporated three tranche searches of 1. review, 2. animal/in vitro and 3. intervention peer reviewed research published in the last 10 years, resulting in a total of 119 papers. Results provide an overview of the NF-kB pathway, a detailed mechanistic examination of the Receptor Activator of Nuclear Factor Kappa-Β Ligand (RANKL) which is linked to bone erosion, and finally a review of nutritional interventions relating to this mechanism of pathophysiology. The accepted papers were critically appraised using SIGN50 for human studies and the ARRIVE guidelines for animal studies; the narrative was and the extracted information coded into key themes.

Effect of large dosage of Prunella on Hashimoto's thyroiditis: A protocol of systematic review and meta-analysis of randomized clinical trials

INTRODUCTION

Hashimoto's Thyroiditis (HT) is one of the common autoimmune diseases, which can lead to thyroid reduction, increase the risk of tumor, and seriously affect women's reproductive health. Many other autoimmune diseases are easy to occur, seriously harming people's health.large dose herb Prunella or compound prescription contain large dose Prunella for treatment of HT has already been confirmed. However, due to the lack of evidence, there is no specific method or suggestion, it is necessary to carry out a systematic evaluation on Prunella and provide effective evidence for further research.

METHODS AND ANALYSIS

The following databases will be searched from their inception to October 2020: Electronic database includes PubMed, Embase, Cochrane Library, Web of Science, Nature, Science online, Chinese Biomedical Database WangFang, VIP medicine information, and China National Knowledge Infrastructure.

MAIN RESULTS

serum thyroid peroxidase antibody (TPOAb), thyroid globulin antibody (TGAb), other results: serum thyroid stimulating hormone (TSH), serum free triiodothyronine (FT3), serum free thyroid hormone (FT4). Data will be extracted by 2 researchers independently, risk of bias of the meta-analysis will be evaluated based on the Cochrane Handbook for Systematic Reviews (SR)of Interventions. All data analysis will be conducted by data statistics software Review Manager V.5.3. and Stata V.12.0.

RESULTS

The results of this study will systematically evaluate the efficacy and safety of large dose prunella salicorrhizae in the intervention of people with HT.

CONCLUSION

The systematic review of this study will summarize the current published evidence of large dose prunella for the treatment of HT, which can further guide the promotion and application of it.

ETHICS AND COMMUNICATION

This study is a systematic review, the outcomes are based on the published evidence, so examination and agreement by the ethics committee are not required in this study. We intend to publish the study results in a journal or conference presentations.Open Science Fra mework (OSF) registration number:October 21, 2020.osf.io/fcyqp. (https://osf.io/fcyqp).

The Human Microbiota in Endocrinology: Implications for Pathophysiology, Treatment, and Prognosis in Thyroid Diseases

The human microbiota is an integral component in the maintenance of health and of the immune system. Microbiome-wide association studies have found numerous diseases associated to dysbiosis. Studies are needed to move beyond correlations and begin to address causation. Autoimmune thyroid diseases (ATD) are one of the most common organ-specific autoimmune disorders with an increasing prevalence, higher than 5% worldwide. Most frequent manifestations of ATD are Hashimoto's thyroiditis and Graves' disease. The exact etiology of ATD remains unknown. Until now it is not clear whether bacterial infections can trigger ATD or modulate the efficacy of treatment and prognosis. The aim of our review is to characterize the microbiota and in ATD and to evaluate the impact of dysbiosis on treatment and prognosis. Moreover, variation of gut microbiome has been associated with thyroid cancer and benign nodules. Here we will characterize the microbioma in benign thyroid nodules, and papillary thyroid cancer to evaluate their implications in the pathophysiology and progression.

Role of selenium and myo-inositol supplementation on autoimmune thyroiditis progression

Previous reports indicate that selenium supplementation may be useful to reduce cell oxidative stress. In particular, selenium may decrease the level of thyroid autoantibodies in patients with Hashimoto's thyroiditis (HT). Recent studies also indicate that myo-inositol may have beneficial effects on thyroid function in patients with HT. Hence, the aim of the present study is to evaluate whether myo-inositol may enhance the protective effect of selenium on HT progression to hypothyroidism. The study was designed as observational and retrospective. Thyroid hormones were evaluated in patients with HT who were either euthyroid or subclinically hypothyroid. These patients were subdivided into three groups: untreated, treated with selenomethionine alone (Se-meth: 83 μg/day) and treated with Se-meth plus myo-inositol (Se-meth + Myo-I: 83 μg/day + 600 mg/day). Outcome evaluation was performed at baseline and after 6 and 12 months of treatment. High-resolution ultrasound of the thyroid gland was performed to evaluate changes in thyroid echoic pattern during the study. Compared to baseline, levels of thyroid-stimulating hormone (TSH) increased significantly in untreated patients but decreased by 31% and 38%, respectively, in those treated with Se-meth and Se-meth + Myo-I. Moreover, in the latter group the TSH reduction was observed earlier than in the Se-meth-treated group. Densitometric analysis of thyroid ultrasonography showed an echoic pattern improvement in both treated groups compared to untreated patients, although this difference was not statistically significant. Thus, Se-meth treatment is effective in patients with HT and its effect may be improved in combination with Myo-I through earlier achievement of TSH levels closer to physiological concentrations.

Serum Selenium Status and Its Interrelationship with Serum Biomarkers of Thyroid Function and Antioxidant Defense in Hashimoto's Thyroiditis

Selenium (Se) deficiency has been implicated in the pathogenesis of Hashimoto’s thyroiditis (HT), although the available evidence is limited. The present study aimed to explore the interrelationships between serum Se status with measures of thyroid function and antioxidant defense in new cases of HT patients with hypoechogenic thyroid. HT patients (n = 49) and matched controls (n = 50) were recruited. Selenium, thyroid hormone panel, thyroid volume (TVol), glutathione (GSH), glutathione peroxidase3 (GPx3) activity, urinary iodine concentration (UIC), and urinary creatinine (Cr) were assessed. HT patients exhibited lower Se levels compared to controls (p < 0.001) with the rates of Se-deficient (<0.85 µmol/L) participants being 58.8% and 34%, respectively. Se-deficient patients exhibited higher thyroid stimulating hormone (TSH), Thyroid volume (TVol), thyroglobulin, antibody-titers, GPx3 activity and UIC/Cr compared to Se-sufficient patients (all p < 0.001). In the Se-deficient patients, inverse correlations were seen between Se-levels with TSH, TVol, and Thyroid peroxidase antibody (TPO-Ab) (all p < 0.001). This study is the first to uncover that coexisting Se-deficiency and elevated iodine in HT may enhance autoimmune reactions and accelerate the deterioration of thyroid function through oxidative stress. Our study also highlights the importance of optimal Se status in this disease, thus providing a rationale for the execution of intervention trials for the evaluation of the clinical benefits of antioxidant-status improvement in HT.

Exposure to a high selenium environment in Punjab, India: Effects on blood chemistry

Many studies have shown that overexposure to environmental selenium may exert a wide pattern of adverse effects on human health, but much uncertainty still surrounds some of them as well as the exact amounts of exposure involved. In particular, very few studies have addressed the possible changes in blood chemistry following high selenium exposure. In a Northeastern part of Punjab, India, very high soil selenium content has been documented, with a value exceeding 2 mg/kg (up to 5) as compared with the <0.5 mg/kg selenium content characterizing the surrounding referent areas. In seven villages located in that seleniferous areas, we carried out a survey by recruiting volunteers and sampling blood, hair and nail specimens. We administered a questionnaire to the participants and analyzed the specimens for the selenium, along with a series of biochemical and haematological parameters in blood. We included 680 adult volunteers (267 men and 413 women), who showed median selenium levels of 171.30 µg/L in serum, 1.25 µg/g in hair, and 5.7 µg/g in nails. Overall, increasing selenium exposure tended to correlate with higher levels of total cholesterol, albumin, free triiodothyronine, deionidase activity, and with red cell and platelet counts. After stratifying the subjects according to category of selenium exposure, we observed a dose-response relation between serum selenium and risk of high total cholesterol, and between hair selenium and risk of high total and low-density lipoprotein cholesterol, high pancreatic lipase, altered thyroid-stimulating hormone and free triiodothyronine levels. Nail selenium exposure category positively correlated with risk of high alanine-aminotransferase, altered albumin levels, high pancreatic lipase and low levels of thyroid-stimulating hormone. Chronic selenium overexposure appears to adversely affect lipid profiles and pancreatic, liver, and thyroid function, with selenium biomarkers having different abilities to predict such effects.

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.

The exploration of Hashimoto's Thyroiditis related miscarriage for better treatment modalities

Hashimoto's thyroiditis (HT) is the most prevalent autoimmune thyroid disease (ATD) worldwide and is strongly associated with miscarriage and even recurrent miscarriage (RM). Moreover, with a deepening understanding, emerging evidence has shown that immune dysfunctions caused by HT conditions, including imbalanced subsets of CD4+ T-helper cells, B regulatory (Breg) cells, high expression levels of CD56dim natural killer (NK) cells, and cytokines, possibly play an important role in impairing maternal tolerance to the fetus. In recent years, unprecedented progress has been made in recognizing the specific changes in immune cells and molecules in patients with HT, which will be helpful in exploring the mechanism of HT-related miscarriage. Based on these findings, research investigating some potentially more effective treatments, such as selenium (Se), vitamin D3, and intravenous immunoglobulin (IVIG), has been well developed over the past few years. In this review, we highlight some of the latest advances in the possible immunological pathogenesis of HT-related miscarriage and focus on the efficacies of treatments that have been widely introduced to clinical trials or practice described in the most recent literature.

Selenium, aging and aging-related diseases

Selenium is an essential trace element in the human body and plays an important role in the body via selenoprotein, which contains selenium. Selenoproteins (glutathione peroxidase, thioredoxin reductase, methionine sulfoxide reductase1 and endoplasmic reticulum-selenoproteins, etc.) have antioxidant effects and are involved in regulating antioxidant activities. Aging is an inevitable process and is always accompanied by aging-related diseases. Reactive oxygen species are important initial factors in aging and aging-related diseases. Selenium contributes to the alleviation of reduced reactive oxygen species-mediated inflammation, reduced DNA damage and prolonged telomere length and thereby plays roles in fighting aging and preventing aging-related diseases. In the elderly, aging-related diseases include neuropsychiatric diseases, tumors, cardiovascular diseases, and skin aging, among others. Selenium supplementation is an important strategy for anti-aging and the prevention of aging-related diseases and is of great significance for the elderly. However, with the accumulation of related research, selenium supplementation does not necessarily contribute to the prevention of aging and aging-related diseases. It is believed that a low level of selenium is beneficial to the human body. Thus, the effect of selenium on human aging and aging-related diseases is still controversial. This paper reviews the research progress and objective role of selenium in aging and aging-related diseases.

Role of Emerging Environmental Risk Factors in Thyroid Cancer: A Brief Review

Environmental factors are recognized as risk factors of thyroid cancer in humans. Exposure to radiation, both from nuclear weapon or fallout or medical radiation, and to some organic and inorganic chemical toxicants represent a worldwide public health issue for their proven carcinogenicity. Halogenated compounds, such as organochlorines and pesticides, are able to disrupt thyroid function. Polychlorinated biphenyls and their metabolites and polybrominated diethyl ethers bind to thyroid, transport proteins, replace thyroxin, and disrupt thyroid function as phthalates and bisphenolates do, highly mimicking thyroid hormones. A better knowledge of environmental risks represents a very important tool for cancer prevention through true risks prevention and management. This approach is very important because of the epigenetic origin’s theory of cancer. Therefore, the aim of this review was study the association between environmental agents and thyroid cancer promotion.

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.

The protective effect of myo-inositol on human thyrocytes

Patients affected by autoimmune thyroiditis reached positive effects on indices of thyroid autoimmunity and/or thyroidal function, after following a treatment with selenomethionine (Se) alone, or Se in combination with Myo-inositol (Myo-Ins). Our purpose was to investigate if Myo-Ins alone, or a combination of Se + Myo-Ins, is effective in protecting thyroid cells from the effects given by cytokines, or hydrogen peroxide (H₂O₂). We assessed the interferon (IFN)-γ-inducible protein 10 (IP-10/CXCL10) secretion by stimulating primary thyrocytes (obtained from Hashimoto's thyroiditis or from control patients) with cytokines in presence/absence of H₂O_2. Our results confirm: 1) the toxic effect of H₂O₂ in primary thyrocytes that leads to an increase of the apoptosis, to a decrease of the proliferation, and to a slight reduction of cytokines-induced CXCL10 secretion; 2) the secretion of CXCL10 chemokine induced by IFN-γ + tumor necrosis factor alpha (TNF)-α has been decreased by Myo + Ins, both in presence or absence of H₂O₂; 3) no effect has been shown by the treatment with Se. Therefore, a protective effect of Myo-Ins on thyroid cells has been suggested by our data, which exact mechanisms are at the basis of this effect need to be furtherly investigated.

TSH evaluation in hypothyroid patients assuming liquid levothyroxine at breakfast or 30 min before breakfast

PURPOSE

To compare TSH levels of hypothyroid patients treated with liquid LT4 at breakfast or 30 min before breakfast.

PATIENTS AND METHODS

Subjects, aged 18-75 years old, were eligible if they presented hypothyroidism, due to Hashimoto's thyroiditis or after thyroidectomy for proven benign goiter. Seven hundred ninety-eight patients were recruited and enrolled in the study. Thirty-seven subjects withdrew from the trial. A total of 761 patients (mean age 46.2 ± 10.8 years) completed the study. The starting dose of LT4 was determined through clinical judgment, taking into account TSH levels, estimated residual thyroid function, age, body weight and comorbidities. All patients underwent TSH, fT4, and fT3 evaluation to verify achievement of euthyroidism with their initial fasting state assumption of LT4 after 8 weeks of therapy. If euthyroidism was not achieved, an appropriately adjusted LT4 dose was administered for 8 weeks, after which thyroid function parameters were checked again. If euthyroidism was achieved, the patients were asked to take LT4 at breakfast and hormone levels were checked again after 6 months.

RESULTS

At the end of the study period, no significant differences in serum TSH level were observed whether LT4 was ingested at breakfast or 30 min prior in a fasting state: 2.61 ± 1.79 vs. 2.54 ± 1.86 mIU/L, respectively (p = 0.455).

CONCLUSIONS

This study confirms in a large set of patients that a liquid LT4 formulation can be taken directly at breakfast and potentially improve therapeutic compliance.

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.

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.

Nutritional and Environmental Factors in Thyroid Carcinogenesis

Several epidemiological studies suggest an increased incidence of thyroid carcinoma (TC) in recent years, especially for the papillary histotype (PTC), suggesting that specific carcinogens might promote molecular abnormalities that are typical of PTC. The increased incidence is probably attributed to more intensive and sensitive diagnostic procedures, even if recent data suggest that various toxic elements could explain the phenomenon. Ionizing radiation exposure represents the most accepted risk factor for differentiated thyroid cancer that includes both the follicular and papillary histotypes. In this review, we examined the other environmental carcinogens that play a role in TC, such as eating habits, living in volcanic areas, and xenobiotic elements. Among eating habits, iodine intake represents one of the more discussed elements, because its deficiency is associated with follicular thyroid carcinomas (FTCs), while its progressive increment seems to be responsible for PTC. The gas, ash, and lava emissions of volcanoes are composed of various toxic compounds that pollute ground water, vegetables, and animals, contaminating humans via the food chain. Finally, the risk of developing PTC has also been associated with exposure of the population to xenobiotics in the environment or in the home. Their carcinogenic effects are probably caused by their accumulation, but additional studies are necessary to better understand the mechanisms of action.

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.

Selenoproteins in human body: focus on thyroid pathophysiology

Selenium (Se) has a multilevel, complex and dynamic effect on the human body as a major component of selenocysteine, incorporated into selenoproteins, which include the selenocysteine-containing enzymes iodothyronine deiodinases. At the thyroid level, these proteins play an essential role in antioxidant protection and hormone metabolism. This is a narrative review based on PubMed/Medline database research regarding thyroid physiology and conditions with Se and Se-protein interferences. In humans, Se-dependent enzyme functions are best expressed through optimal Se intake, although there is gap in our knowledge concerning the precise mechanisms underlying the interrelation. There is a good level of evidence linking low serum Se to autoimmune thyroid diseases and, to a lesser extent, differentiated thyroid cancer. However, when it comes to routine supplementation, the results are heterogeneous, except in the case of mild Graves' orbitopathy. Autoimmune hypothyroidism is associated with a state of higher oxidative stress, but not all studies found an improvement of thyroid function after Se was introduced as antioxidant support. Meanwhile, no routine supplementation is recommended. Low Se intake is correlated with an increased risk of developing antithyroid antibodies, its supplementation decreasing their titres; there is also a potential reduction in levothyroxine replacement dose required for hypothyroidism and/or the possibility that it prevents progression of subclinical hypothyroidism, although not all studies agree. In thyroid-associated orbitopathy, euthyroidism is more rapidly achieved if the micronutrient is added to traditional drugs, while controls appear to benefit from the microelement only if they are deficient; thus, a basal assay of Se appears advisable to better select patients who need substitution. Clearly, further Se status biomarkers are required. Future introduction of individual supplementation algorithms based on baseline micronutrient levels, underlying or at-risk clinical conditions, and perhaps selenoprotein gene polymorphisms is envisaged.

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.

Levothyroxine monotherapy versus levothyroxine and selenium combination therapy in chronic lymphocytic thyroiditis

PURPOSE

New strategies are needed for prevention and treatment of chronic lymphocytic thyroiditis (CLT). This study aimed to assess whether combination of levothyroxine treatment and selenium (Se) supplementation results in improved therapeutic effects in CLT compared with levothyroxine monotherapy.

METHODS

An open-label, randomized controlled study was performed in 60 CLT patients assigned to two groups. Levothyroxine group (LT) patients (n = 24) received levothyroxine alone for 3 months; meanwhile, the combination (LTSS) group (n = 36) was administered levothyroxine with selenium yeast capsule. Blood selenium concentrations, anti-thyroid peroxidase (TPO) and anti-thyroglobulin (Tg) antibody levels, and inflammatory cytokine amounts were compared between both groups before and after treatment.

RESULTS

At baseline, similar values were obtained in both groups for all the parameters assessed (p > 0.05). After treatment, significantly increased blood selenium levels (µg/L) [90.05 (80.69, 107.76) vs. 39.64 (29.42, 51.10), p < 0.001] and decreased anti-TPO antibody (23.63 ± 9.31 vs. 32.00 ± 10.41%, p = 0.002), anti-Tg antibody (35.84 ± 15.21 vs. 45.47 ± 14.24%, p = 0.015) and IL-2 amounts (pg/mL) [159.29 (124.54, 189.70) vs. 226.48 (190.74, 266.56), p < 0.001] were observed in the LTSS group compared with the LT group post-treatment; meanwhile, similar IL-10 concentrations [23.14 (21.65, 28.56) pg/mL vs. 24.68 (21.71, 29.67) pg/mL] were obtained in both groups. Subgroup analysis of patients with hypothyroidism showed the same trend observed in the whole population; in patients with normal thyroid function, only Se and IL-2 amounts differed between the two treatment groups. Correlation analysis of of the indexes: in HT patients, the basal serum selenium concentration was positively correlated with TT₄ (r = 0.294, p < 0.05), significantly negatively correlated with TSH (r = -0.343, p < 0.01), and had no significant correlation with TT3 (p > 0.05).

CONCLUSIONS

These findings indicated that levothyroxine and selenium combination results in improved therapeutic effects than the levothyroxine monotherapy in preventing CLT progression.

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.

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.

Selenium supplementation modulates apoptotic processes in thyroid follicular cells

Selenium (Se) is an essential micronutrient modulating several physiopathological processes in the human body. The aim of the study is to characterize the molecular effects determined by Se-supplementation in thyroid follicular cells, using as model the well-differentiated rat thyroid follicular cell line FRTL5. Experiments have been performed to evaluate the effects of Se on cell growth, mortality and proliferation and on modulation of pro- and antiapoptotic pathways. The results indicate that Se-supplementation improves FRTL5 growth rate. Furthermore, Se reduces the proportion of cell death and modulates both proapoptotic (p53 and Bim) and antiapoptotic (NF-kB and Bcl2) mRNA levels. In addition, incubation with high doses of Na-Se might prevent the ER-stress apoptosis induced by tunicamycin, as assessed by membrane integrity maintenance, reduction in caspase 3/7 activities, and reduction in Casp-3 and PARP cleavage. Taken together, these results provide molecular evidences indicating the role of Se supplementation on cell death and apoptosis modulation in thyroid follicular cells. These observations may be useful to understand the effects of this micronutrient on the physiopathology of the thyroid gland. © 2016 BioFactors, 43(3):415-423, 2017.

Autoimmune thyroid diseases in children

Autoimmune thyroid diseases (AIT) are common in children and may present with a variety of signs and symptoms including: euthyroid goiter, hypothyroidism, or hyperthyroidism. The natural history of AIT may be different in children but in all age groups, there appear to be genetic risk factors and environmental triggers that initiate thyroid autoimmunity. Areas covered: In this review, we summarize recent studies that investigate the genetics and environmental triggers believed to be involved in thyroid autoimmunity. We also discuss the approach and controversies in the treatment of children with AIT. Expert commentary: Much has been learned about the major roles for genetics, cytokines, regulatory lymphocytes, and environmental triggers in CLT but controversies remain.

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.

Environmental Issues in Thyroid Diseases

Environmental factors are determinant for the appearance of autoimmune thyroid diseases (AITD) in susceptible subjects. Increased iodine intake, selenium, and vitamin D deficiency, exposure to radiation, from nuclear fallout or due to medical radiation, are environmental factors increasing AITD. Cigarette smoking is associated with Graves' disease and Graves' ophthalmopathy, while it decreases the risk of hypothyroidism and thyroid autoimmunity. Viral infections are important environmental factors in the pathogenesis of AITD, too, particularly human parvovirus B19 (EVB19) and hepatitis C virus. Among the many chemical contaminants, halogenated organochlorines and pesticides variably disrupt thyroid function. Polychlorinated biphenyls and their metabolites and polybrominated diethyl ethers bind to thyroid transport proteins, such as transthyretin, displace thyroxine, and disrupt thyroid function. Among drugs, interferon- and iodine-containing drugs have been associated with AITD. Moreover intestinal dysbiosis causes autoimmune thyroiditis. To reduce the risk to populations and also in each patient, it is necessary to comprehend the association between environmental agents and thyroid dysfunction.