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

Monitoring of Essential and Toxic Elements in Multivitamin/Mineral Effervescent Tablet Supplements and Safety Assessment

Multivitamin/mineral (MVM) supplements are the most commonly utilized dietary supplements by many populations. However, there is a severe concern about their adverse effects due to elemental impurities. In the present study, it was aimed to determine the levels of 11 elemental impurities (Cd, Pb, As, Hg, Co, V, Ni, Se, Mo, Cu, and Cr) by inductively coupled plasma-mass spectrometry (ICP-MS) and evaluate the human health risk associated with the consumption of 33 MVM effervescent tablet supplements available in Turkey. The precision of the method in terms of relative standard deviation (RSD) was less than 4.6%. The accuracy of the method was tested with recovery experiments, and the results ranged between 86 and 107%. The impurity levels for Cd, Pb, As, Co, V, Ni, Se, Mo, Cu, and Cr were found between 0.011-0.050, 0.025-0.098, 0.018-0.056, 0.010-0.626, 0.027-0.290, 0.026-1.65, 1.92-21.83, 0.034-34.09, 0.140-183.9, and 0.033-13.10 µg/g, respectively, and Hg was not detected in any sample. The calculated concentrations for elemental impurities complied with EMA and USP guidelines, except one supplement for Se (21.83 µg/g) with a permitted limit of 15 µg/g. The hazard quotient (HQ) and hazard index (HI) levels were below 1 for all samples within the ranges of 3.4 × 10-1-1.4 × 10-6 for HQ and 7.8 × 10-1-1.4 × 10-6 for HI indicating that there is no risk for consumption. The carcinogenic risk (CR) of As was between 1.7 × 10-6 and 5.9 × 10-6, below the threshold value of 1 × 10-4. The results showed that there is no risk to human health.

Autoimmune Thyroid Diseases

Autoimmune thyroid diseases (AITDs) include a wide spectrum of thyroid diseases affecting more commonly women than men. The most frequent forms are Graves' Disease (GD) and Hashimoto's thyroiditis / Autoimmune Thyroiditis (AIT), but there are also other immunogenic destructive forms of thyroiditis, that is, silent and postpartum thyroiditis. In the last decade, AITDs and other inflammatory thyroid diseases related to anti-tumor molecular drugs are more frequently seen due to the widespread use of tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICPIs). Autoimmune thyroiditis related to SARS-CoV-2 infection has been a novel entity in recent years. Graves' Disease and AIT may shift from hyperthyroidism to hypothyroidism, which may complicate the differential diagnosis and further treatment strategy. Moreover, all AITDs may manifest with thyrotoxicosis (a clinical condition marked with high serum levels of thyroid hormones) which has to be distinguished from hyperthyroidism (increased thyroid hormone production and secretion as a result of hyperfunctioning thyroid gland) due to different therapeutic approaches. Nuclear medicine techniques, such as radioiodine uptake (RAIU) and thyroid scintigraphy, using 99mTc- pertechnetate (Na[99mTc]TcO4) or 123-Iodine (Na[123I]I), have a crucial role in the differential diagnosis. Measurement of thyroid antibodies, e.g. thyroid peroxidase antibodies (TPO) and thyrotropin receptor antibodies (TRAb), as well as thyroid ultrasound, are complementary methods in the evaluation of thyroid disorders.

From Conception to Delivery: A Comprehensive Review of Thyroid Disorders and Their Far-Reaching Impact on Feto-Maternal Health

This comprehensive review delves into the multifaceted landscape of thyroid disorders during pregnancy, exploring their impact from conception to postpartum considerations. Key findings highlight the intricate interplay between maternal thyroid health and fetal development, emphasizing the critical importance of timely screening and targeted interventions. The evolving landscape of research and technology suggests a paradigm shift toward personalized approaches in clinical practice, emphasizing integrated care models and the integration of telehealth platforms. Postpartum considerations, including postpartum thyroiditis, underscore the necessity for ongoing monitoring and intervention for maternal well-being. Implications for clinical practice encompass healthcare provider education, public awareness campaigns, and policy advocacy for standardized screening guidelines. The call to action resonates for increased research funding to advance understanding and improve outcomes. By fostering awareness, education, and collaborative efforts, this review aims to navigate the complexities of thyroid disorders during pregnancy, ensuring a healthier start for both mothers and their infants.

The prevalence of subclinical hypothyroidism in a pre-diabetes population and an analysis of related factors

BACKGROUND

To investigate the prevalence and related influencing factors of subclinical hypothyroidism (SCH) in a pre-diabetes (PreDM) population.

PATIENTS AND METHODS

A multi-stage stratified cluster random sampling method was used to select the adult Han population in Gansu Province for investigation. General data and related biochemical indices were recorded and SPSS software was used for statistical analyses.

RESULTS

This study selected 2876 patients, including 548 with SCH and 433 with PreDM. In the PreDM population, the levels of thyroid stimulating hormone (TSH), serum phosphorus, TPOAb and TgAb in the SCH group were higher than those in the euthyroid group (P < 0.05). The level of TPOAb in females of SCH group was higher than that in males (P < 0.05). The positive rates of TPOAb and TgAb in females were higher than those in males in the total population and SCH population. The prevalence of SCH in the PreDM group under 60 was significantly higher than that in the normal glucose tolerance (NGT) group (26.02% vs. 20.40%, χ² = 5.150, P < 0.05). We defined SCH as a TSH level of >4.20 mIU/L. Using this criterion, the prevalence of SCH in the total population of PreDM was higher than that in the NGT population (χ² = 8.611, P < 0.05), the prevalence of SCH in the PreDM population generally showed an upward trend. However, we performed a separate analysis considering the accepted impact of age on TSH redefining SCH as TSH >8.86 mIU/L (for individuals over age 65). However, allowing for the expected rise in TSH levels in individuals over age 65, the prevalence of SCH in the elderly over 65 years of age decreased significantly (NGT population from 27.48% to 9.16%, PreDM population from 34.18% to 6.33%, P < 0.05). Logistic regression analysis showed that the risk factors for SCH in the PreDM population were female gender, fasting plasma glucose and TSH (all P < 0.05). Risk factors for SCH in the impaired fasting glucose (IFG) population were female gender, OGTT 2 h, TSH and TPOAb (all P < 0.05).

CONCLUSION

The prevalence of SCH in the PreDM population not considering the known physiological increase in age related TSH was relatively high and was significant in female and the IFG population. However, the effect of age on these findings needs to attract more attention.

Selenium regulates T cell differentiation in experimental autoimmune thyroiditis in mice

Selenium (Se) is an essential trace element that plays an important role in thyroid physiology. Se supplementation can reduce levels of autoimmune thyroid antibodies, which may be beneficial in Hashimoto's thyroiditis (HT). However, the long-term benefits of Se supplementation for HT patients are controversial and there is no clear clinical evidence to support it, so further basic and clinical research is needed. The effect of Se on immune cells, especially T cells, in autoimmune thyroiditis (AIT) has not been elucidated. Here, we replicated a mouse model of experimental autoimmune thyroiditis (EAT) on a high-iodine diet and treated it with Se supplementation. At week 8 of the experiment, Se supplementation reduced the destruction of thyroid follicles and the infiltration rate of lymphocytes in EAT mice, and reversed the disturbance of peripheral blood thyroxine and thyroid autoantibody levels. Further examination revealed that Se had broad effects on T-cell subsets. Its effects include reducing the production of pro-inflammatory cytokines by Th1 cells, inhibiting the differentiation and production of cytokines by Th2 and Th17 cells, and upregulating the differentiation and production of cytokines by Treg cells. These changes help alleviate thyroid follicle damage during EAT. In conclusion, selenium supplementation has the potential to improve the prognosis of AIT by altering the subset differentiation and/or function of CD4+ T cells.

Investigation of the levels of essential and non-essential metals in women with and without abortion history: A study based on the Persian population of the Shahrekord cohort

Spontaneous abortion is a serious threat to the mothers' physical and mental well-being. The cause of spontaneous abortion is multifactorial disease. Prenatal non-essential metal exposure, particularly heavy metals, has been suggested to be associated with adverse pregnancy and birth outcomes. The purpose of this study was to investigate the relationship between the concentration of essential and non-essential metals including Pb, As, Zn, and Se and the risk of spontaneous abortion. In this case-control study the levels of Pb, As, Zn, and Se in the whole blood of 60 women with spontaneous abortion (case group) and also 60 women without spontaneous abortion (control group) were measured by atomic absorption spectrophotometry. Results revealed statistically significant reductions (P < 0.001) in whole blood levels of Zn and Se as well as the levels of As and Pb had a substantial elevation (P < 0.001) in cases compared to controls. According to the findings, repeated spontaneous abortion may be influenced by increasing whole blood levels of heavy metals such as As (OR = 17.53, P = 0.001) and Pb (OR = 15.58, P = 0.001) as well as decreasing levels of vital micronutrients Zn (OR = 0.20, P = 0.001) and Se (OR = 0.14, P = 0.001). The results of this study support the idea that limiting intake of non-essential metals during pregnancy can decrease the risk of spontaneous abortion. Overall, the information presented is expected to help plan future fundamental and applied investigations on the spontaneous abortion.

Selenium, selenoproteins and cancer of the thyroid

Selenium is an essential mineral element with important biological functions for the whole body through incorporation into selenoproteins. This element is highly concentrated in the thyroid gland. Selenoproteins provide antioxidant protection for this tissue against the oxidative stress caused by free radicals and contribute, via iodothyronine deiodinases, to the metabolism of thyroid hormones. It is known that oxidative stress plays a major role in carcinogenesis and that in recent decades there has been an increase in the incidence of thyroid cancer. The anti-carcinogenic action of selenium, although not fully understood, is mainly attributable to selenoproteins antioxidant properties, and to the ability to modulate cell proliferation (cell cycle and apoptosis), energy metabolism, and cellular immune response, significantly altered during tumorigenesis. Researchers have suggested that different forms of selenium supplementation may be beneficial in the prevention and treatment of thyroid cancer; however, the studies have several methodological limitations. This review is a summary of the current knowledge on how selenium and selenoproteins related to thyroid cancer.

Effect of Gestational Pesticide Exposure on the Child's Respiratory System: A Narrative Review

BACKGROUND

In recent years, concern has arisen worldwide about the potential adverse effects that could result from early-life exposure to pesticides. Asthma, bronchitis, and persistent cough in children have been linked to gestational exposure to pesticides. The respiratory effects of gestational exposure to pesticides are controversial. The aim of this study was to determine the relationship between pesticide exposure in pregnant women and its effect on the respiratory system of their children.

METHODS

A narrative review was carried out by means of a search in the main databases.

RESULTS

Findings of studies confirmed the effects of pesticides on the child's health. These substances cross the placenta and become transmitters of exposure to the individual at the most sensitive stage of her development.

CONCLUSIONS

Chronic exposure to pesticides in fetuses is associated with chronic respiratory symptoms and disease.

Selenoprotein P - Selenium transport protein, enzyme and biomarker of selenium status

The habitual intake of selenium (Se) varies strongly around the world, and many people are at risk of inadequate supply and health risks from Se deficiency. Within the human organism, efficient transport mechanisms ensure that organs with a high demand and relevance for reproduction and survival are preferentially supplied. To this end, selenoprotein P (SELENOP) is synthesized in the liver and mediates Se transport to essential tissues such as the endocrine glands and the brain, where the "SELENOP cycle" maintains a privileged Se status. Mouse models indicate that SELENOP is not essential for life, as supplemental Se supply was capable of preventing the development of severe symptoms. However, knockout mice died under limiting supply, arguing for an essential role of SELENOP in Se deficiency. Many clinical studies support this notion, pointing to close links between health risks and low SELENOP levels. Accordingly, circulating SELENOP concentrations serve as a functional biomarker of Se supply, at least until a saturated status is achieved and SELENOP levels reach a plateau. Upon toxic intake, a further increase in SELENOP is observed, i.e., SELENOP provides information about possible selenosis. The SELENOP transcripts predict an insertion of ten selenocysteine residues. However, the decoding is imperfect, and not all these positions are ultimately occupied by selenocysteine. In addition to the selenocysteine residues near the C-terminus, one selenocysteine resides central within an enzyme-like environment. SELENOP proved capable of catalyzing peroxide degradation in vitro and protecting e.g. LDL particles from oxidation. An enzymatic activity in the intact organism is unclear, but an increasing number of clinical studies provides evidence for a direct involvement of SELENOP-dependent Se transport as an important and modifiable risk factor of disease. This interaction is particularly strong for cardiovascular and critical disease including COVID-19, cancer at various sites and autoimmune thyroiditis. This review briefly highlights the links between the growing knowledge of Se in health and disease over the last 50 years and the specific advances that have been made in our understanding of the physiological and clinical contribution of SELENOP to the current picture.

Seleno-Metabolites and Their Precursors: A New Dawn for Several Illnesses?

Selenium (Se) is an essential element for human health as it is involved in different physiological functions. Moreover, a great number of Se compounds can be considered potential agents in the prevention and treatment of some diseases. It is widely recognized that Se activity is related to multiple factors, such as its chemical form, dose, and its metabolism. The understanding of its complex biochemistry is necessary as it has been demonstrated that the metabolites of the Se molecules used to be the ones that exert the biological activity. Therefore, the aim of this review is to summarize the recent information about its most remarkable metabolites of acknowledged biological effects: hydrogen selenide (HSe⁻/H₂Se) and methylselenol (CH₃SeH). In addition, special attention is paid to the main seleno-containing precursors of these derivatives and their role in different pathologies.