Autoimmune thyroiditis and ROS

Traditional Chinese Medicine for Hashimoto's Thyroiditis: Focus on Selenium and Antioxidant Phytochemicals

Hashimoto's thyroiditis (HT) is not only the most frequent autoimmune thyroid disease (AITD), but it also has a significant impact on patients' health-related quality of life (HRQoL), and it has been variably associated with differentiated thyroid carcinoma. Even though its pathogenesis is still incompletely understood, oxidative stress is believed to play an important role. Hypothyroidism related to later stages of HT can be treated with levothyroxine substitution therapy; various approaches such as selenium supplementation and iodine-restricted diets have been proposed as disease-modifying treatments for earlier stages, and even thyroidectomy has been suggested for refractory cases of painful HT. Nevertheless, many patients still report suboptimal HRQoL, highlighting an unmet medical need in this area. The concepts and approaches of traditional Chinese medicine (TCM) in treating HT are not broadly known in the West. Here, we provide an overview of TCM for HT, including combinations of TCM with selenium. We encompass evidence from clinical trials and other studies related to complex TCM prescriptions, single herbs used in TCM, and phytochemicals; wherever possible, we delineate the probable underlying molecular mechanisms. The findings show that the main active components of TCM for HT have commonly known or presumed antioxidant and anti-inflammatory activities, which may account for their potential utility in HT. Further exploring the practices of TCM for HT and combining them with evidence- and mechanism-based approaches according to Western standards may help to identify new strategies to alter the clinical course of the disease and/or to treat patients' symptoms better and improve their HRQoL.

Clinical efficacy and molecular mechanism of Chinese medicine in the treatment of autoimmune thyroiditis

ETHNOPHARMACOLOGICAL RELEVANCE

Autoimmune Thyroiditis (AIT) is a common refractory autoimmune disease of the endocrine system that may eventually lead to complete loss of thyroid function, with subsequent severe effects on the metabolism. Because of the deficiency in current clinical management of AIT, the need for alternative therapies is highlighted. With its multi-component and multi-target characteristics, Chinese medicine has good potential as an alternative therapy for AIT.

AIM OF THE STUDY

The aim of this study was to systematically summarize the clinical efficacy and safety evaluation of TCM and its active ingredients in the treatment and regulation of AIT. Additionally, we provide an in-depth discussion of the relevant mechanisms and molecular targets to understand the protective effects of traditional Chinese medicine on AIT and explore new ideas for clinical treatment.

MATERIALS AND METHODS

The literature related to "Hashimoto", "autoimmune thyroiditis", "traditional Chinese medicine," and "Chinese herbal medicine" was systematically summarized and reviewed from Web of Science Core Collection, PubMed, CNKI, and other databases. Domestic and international literature were analyzed, compared, and reviewed.

RESULTS

An increasing number of studies have demonstrated that herbal medicines can intervene in immunomodulation, with pharmacological effects such as antibody lowering, anti-inflammatory, anti-apoptotic thyroid follicular cells, regulation of intestinal flora, and regulation of estrogen and progesterone levels. The signaling pathways and molecular targets of the immunomodulatory effects of Chinese herbal medicine for AIT may include Fas/FasL, Caspase, BCL-2, and TLRs/MyD88/NF-κB et al. CONCLUSIONS: The use of Chinese herbs in the treatment and management of AIT is clinically experienced, satisfactory, and safe. Future studies may evaluate the influence of herbal medicines on the occurrence and development of AIT by modulating the interaction between immune factors and conventional signaling pathways.

Intestinal microbiota regulates the gut-thyroid axis: the new dawn of improving Hashimoto thyroiditis

Intestinal microbiota plays an indispensable role in the host's innate immune system, which may be related to the occurrence of many autoimmune diseases. Hashimoto thyroiditis (HT) is one of the most common autoimmune diseases, and there is plenty of evidence indicating that HT may be related to genetics and environmental triggers, but the specific mechanism has not been proven clearly. Significantly, the composition and abundance of intestinal microbiota in patients with HT have an obvious difference. This phenomenon led us to think about whether intestinal microbiota can affect the progress of HT through some mechanisms. By summarizing the potential mechanism of intestinal microflora in regulating Hashimoto thyroiditis, this article explores the possibility of improving HT by regulating intestinal microbiota and summarizes relevant biomarkers as therapeutic targets, which provide new ideas for the clinical diagnosis and treatment of Hashimoto thyroiditis.

Higher Levels of Plasma Fetuin-A, Nrf2, and Cytokeratin 18 in Patients with Hashimoto's Disease

Objectives

Fetuin-A is a protein that exhibits proatherogenic, pro-inflammatory, and anti-inflammatory effects with increased insulin resistance and adipocyte dysfunction. The nuclear factor erythroid 2-related factor (Nrf2) is a transcription factor that is crucial for protecting cells against oxidative damage. As a cell death product, cytokeratin 18 (CK18) levels increase during necrosis and apoptosis of both normal and tumor cells. We analyzed the plasma levels of three biomarkers based on the hypothesis that they might be related to some pathophysiological pathways in Hashimoto's disease.

Methods

We compared 34 female patients with overt hypothyroidism due to Hashimoto's disease (Group 1) with 34 age-matched healthy females (Group 2). For comparison, plasma levels of thyroid-stimulating hormone (TSH), fetuin-A, Nrf2, and CK18 were measured in all participants.

Results

In group 1, the mean TSH levels (31.4±15.3) were significantly higher than those in group 2 (2.6±1.0) (p<0.001). The levels of mean fetuin-A (606.7±34.2) and Nrf2 (1.3±0.6) were found to be significantly higher in group 1 than in group 2 (440.0±34.2 vs. 0.7±0.2) (p<0.001 for both). CK18 levels in group 1 (0.36±0.13) were also significantly higher than in group 2 (0.26±0.16) (p=0.020). A significant correlation was observed between TSH levels and fetuin-A (r=0.401, p=0.001).

Conclusion

Increased levels of fetuin-A, Nrf2, and CK18 may be a consequence or cause of the pathophysiological pathways of Hashimoto's disease. The clinical significance of increased levels of these biomarkers requires further investigation.

Effect of iodine nutritional status on the recurrence of hyperthyroidism and antithyroid drug efficacy in adult patients with Graves' disease: a systemic review

Aim

To probe the appropriate iodine nutritional status for patients with Graves'disease (GD) hyperthyroidism and on antithyroid drugs (ATD) or after drugwithdrawal.

Method

Studies were retrieved from three databases (Embase, Medline, and Cochrane Library) and were screened and evaluated using predefined criteria. The risk of bias of each trial was assessed using a tool from Cochrane. The iodine nutritional status of the subjects was redefined according to the World Health Organization (WHO) criteria and classified as insufficient/adequate/above requirements/excessive iodine intake.

Result

Two randomized controlled trials (RCTs) and 3 observational studies were selected from the 376 retrieved papers, which had different degrees of risk of bias in study design. The heterogeneity among them prevented us from further synthesizing effect indicators and subsequent statistical analyses. Two RCTs with high quality showed that insufficient or above requirements iodine intake was detrimental for ATD-treated GD patients; adequate iodine intake was associated with a lower risk of recurrence and better efficacy in controlling thyrotoxicosis. It could be speculated from three low-quality observational studies that excessive iodine intake may be associated with higher (or similar) recurrence rates and lower remission rates compared to above requirements iodine intake in these patients, but none of them could answer the question of the effect of insufficient or adequate iodine intake on this issue.

Conclusion

Although the available evidence is suboptimal, this systematic review tentatively suggests that in adult patients with GD hyperthyroidism receiving ATDs and according to WHO criteria for iodine nutritional status, adequate iodine intake is associated with a lower recurrence rate, a higher remission rate and a better efficacy to control thyrotoxicosis than insufficient, above requirement, or excessive iodine intake. Future RCTs with large samples are expected to elucidate the actual impact of different iodine nutritional statuses on the recurrence rate of hyperthyroidism and the efficacy of ATD to control thyrotoxicosis in these patients.

Systematic review registration

identifier CRD42022359451.

The Effects of Selenium Supplementation in the Treatment of Autoimmune Thyroiditis: An Overview of Systematic Reviews

OBJECTIVE

The available evidence on selenium supplementation in the treatment of autoimmune thyroiditis (AIT) was inconclusive. This research serves to assess the effects of selenium supplementation in the treatment of AIT.

METHODS

Online databases including PubMed, Web of Science, Embase, and the Cochrane Library were searched from inception to 10 June 2022. The AMSTAR-2 tool was used to assess the methodological quality of included studies. The information on the randomized controlled trials of the included studies was extracted and synthesized. The GRADE system was used to assess the certainty of evidence.

RESULTS

A total of 6 systematic reviews with 75 RCTs were included. Only one study was rated as high quality. The meta-analysis showed that in the levothyroxine (LT4)-treated population, thyroid peroxidase antibody (TPO-Ab) levels decreased significantly in the selenium group at 3 months (SMD = -0.53, 95% CI: [-0.89, -0.17], p < 0.05, very low certainty) and 6 months (SMD = -1.95, 95% CI: [-3.17, -0.74], p < 0.05, very low certainty) and that thyroglobulin antibody (Tg-Ab) levels were not decreased. In the non-LT4-treated population, TPO-Ab levels decreased significantly in the selenium group at 3 and 6 months and did not decrease at 12 months. Tg-Ab levels decreased significantly in the selenium group at 3 and 6 months and did not decrease at 12 months. The adverse effects reported in the selenium group were not significantly different from those in the control group, and the certainty of evidence was low.

CONCLUSION

Although selenium supplementation might reduce TPO-Ab levels at 3 and 6 months and Tg-Ab levels at 3 and 6 months in the non-LT4-treated population, this was based on a low certainty of evidence.

Severe Autoimmune Thyroiditis in Transgenic NOD.H2h4 Mice Expressing Interleukin-4 in the Thyroid

Background: Hashimoto's thyroiditis is a common autoimmune thyroid disorder characterized by thyroid lymphocytic infiltrates and autoreactive antibodies against thyroglobulin (TgAbs) and thyroperoxidase. Final evolution of the disease can lead to hypothyroidism with destruction of the thyroid architecture. Interleukin-4 (IL-4) is involved in the humoral immune response and B cell activation required in autoimmune thyroiditis (AT) progression. We used our mouse model overexpressing IL-4 by thyrocytes (Thyr-IL4) to study the impact of a local IL-4 expression in AT using transgenic nonobese diabetic (NOD.H2^h4) derived animals treated with iodide-supplemented water to increase the incidence of spontaneous AT (SAT). Methods: Thyr-IL4 NOD.H2^h4 and nonpathogenic C57BL/6 animals aged 8 weeks were exposed to 0.05% sodium iodide (NaI) in their drinking water for 8 and 16 weeks. Circulating TgAbs and expression of intrathyroidal cytokines were quantified. Thyroid inflammation was assessed by classical histological analyses, including identification of some immune cell populations. The most sensitive parameter to evaluate the thyroid function, serum thyrotropin (TSH), was also measured at the end of the treatment. Results: Relative to wild-type (WT) animals, Thyr-IL4 NOD.H2^h4 mice developed severe accelerated SAT with elevated serum TgAbs and numerous thyroid infiltrates mainly composed of CD4⁺/CD8⁺ T cells, B lymphocytes, and monocytes/macrophages. Thyroid expression of T helper (Th) Th1/Th2 cytokines was also enhanced, as well as IL-17. In contrast, excessive iodide supply did not induce TgAbs in WT and Thyr-IL4 SAT-resistant C57BL/6 animals. However, moderate leukocyte infiltrations in transgenic thyroids were evident compared to WT, but associated with a limited number of T and B cells and a different cytokine profile from Thyr-IL4 NOD.H2^h4 mice. Finally, and despite their diverse immune responses, both transgenic strains presented marked thyroid enlargement and elevated serum TSH at the end of the treatment in contrast to their WT littermates. Conclusions: These findings demonstrated that ectopic expression of IL-4 from thyrocytes enhanced the severity of accelerated SAT in disease-prone Thyr-IL4 NOD.H2^h4 animals and promoted thyroid leukocyte infiltration in SAT-resistant transgenic C57BL/6 mice. Moreover, impaired thyroid function emerged in both transgenic strains during the progression of the disease.

Advances in Human Mitochondria-Based Therapies

Mitochondria are the key biological generators of eukaryotic cells, controlling the energy supply while providing many important biosynthetic intermediates. Mitochondria act as a dynamic, functionally and structurally interconnected network hub closely integrated with other cellular compartments via biomembrane systems, transmitting biological information by shuttling between cells and tissues. Defects and dysregulation of mitochondrial functions are critically involved in pathological mechanisms contributing to aging, cancer, inflammation, neurodegenerative diseases, and other severe human diseases. Mediating and rejuvenating the mitochondria may therefore be of significant benefit to prevent, reverse, and even treat such pathological conditions in patients. The goal of this review is to present the most advanced strategies using mitochondria to manage such disorders and to further explore innovative approaches in the field of human mitochondria-based therapies.

Iodine as a potential endocrine disruptor-a role of oxidative stress

PURPOSE

Iodine is an essential micronutrient required for thyroid hormone biosynthesis. However, overtreatment with iodine can unfavorably affect thyroid physiology. The aim of this review is to present the evidence that iodine-when in excess-can interfere with thyroid hormone synthesis and, therefore, can act as a potential endocrine-disrupting chemical (EDC), and that this action, as well as other abnormalities in the thyroid, occurs-at least partially-via oxidative stress.

METHODS

We reviewed published studies on iodine as a potential EDC, with particular emphasis on the phenomenon of oxidative stress.

RESULTS

This paper summarizes current knowledge on iodine excess in the context of its properties as an EDC and its effects on oxidative processes.

CONCLUSION

Iodine does fulfill the criteria of an EDC because it is an exogenous chemical that interferes-when in excess-with thyroid hormone synthesis. However, this statement cannot change general rules regarding iodine supply, which means that iodine deficiency should be still eliminated worldwide and, at the same time, iodine excess should be avoided. Universal awareness that iodine is a potential EDC would make consumers more careful regarding their diet and what they supplement in tablets, and-what is of great importance-it would make caregivers choose iodine-containing medications (or other chemicals) more prudently. It should be stressed that compared to iodine deficiency, iodine in excess (acting either as a potential EDC or via other mechanisms) is much less harmful in such a sense that it affects only a small percentage of sensitive individuals, whereas the former affects whole populations; therefore, it causes endemic consequences.

Emerging roles of Keap1/Nrf2 signaling in the thyroid gland and perspectives for bench-to-bedside translation

The signaling pathway centered on the transcription factor nuclear erythroid factor 2-like 2 (Nrf2) has emerged during the last 15 years as a target for the prevention and treatment of diseases broadly related with oxidative stress such as cancer, neurodegenerative and metabolic diseases. The roles of Nrf2 are expanding beyond general cytoprotection, and they encompass its crosstalk with other pathways as well as tissue-specific functions. The thyroid gland relies on reactive oxygen species for its main physiological function, the synthesis and secretion of thyroid hormones. A few years ago, Nrf2 was characterized as a central regulator of the antioxidant response in the thyroid, as well as of the transcription and processing of thyroglobulin, the major thyroidal protein that serves as the substrate for thyroid hormone synthesis. Herein, we summarize the current knowledge about the roles of Nrf2 in thyroid physiology, pathophysiology and disease. We focus specifically on the most recent publications in the field, and we discuss the implications for the preclinical and clinical use of Nrf2 modulators.

Receptor of advanced glycation end product (RAGE) polymorphism and oxidative status in Hashimoto’s thyroiditis in Egyptian female patients: case control study

Background

Hashimoto's thyroiditis is the most widespread autoimmune illness targeting a specific organ. "Redox homeostasis" is achieved when the production of Reactive Oxygen Species and their elimination are in balance. Advanced glycation end products (AGEs) are formed when glucose and/or α-oxaloaldehydes react non-enzymatically with the amino groups of lipids, proteins, and DNA. Nowadays, many studies are concerned with AGEs, the polymorphisms of their receptors, and their association with increased risk of HT. However, few studies investigated the role of receptors of advanced glycation end product (RAGE) SNP in Egyptian females.

Objective

The goals of this investigation were to ascertain whether oxidative stress plasma malondialdehyde (MDA) and total antioxidant capacity (TAC) were associated with HT, in addition, to assess the association of RAGE polymorphisms (− 374 T > A and the − 429 T > C and Gly82Ser) with HT.

Subject and methods.

Our case–control study has 80 patients enrolled who have newly been diagnosed with HT and 80 age and sex-matched healthy female controls. Each participant underwent a thorough medical history, physical examination, and laboratory investigations, which included Genotyping of RAGE Gly82Ser, − 374 T > A and − 429 T > C using polymerase chain reaction-restriction fragment length polymorphisms (PCR–RFLP).

Results

Chi-square revealed a significant association regarding the distribution of RAGE (− 374 T < C) genotypes TT and CC between patients and control (P = 0.04). Non-significant associations regarding the distribution of Gly82Ser genotypes Gly/Gly, Gly/Ser, Ser/Ser were found between patients and control (P = 0.5), and non-significant associations related to − 429 T > C gene polymorphism were revealed. In addition, patients with HT had higher MDA and lower TCA compared with controls.

Conclusion

The elevated MDA and decreased TAC as an antioxidant may be one of several risk factors associated with the prevalence of HT in individuals with the − 429 T > C RAGE mutation polymorphism that is associated with an increased risk of HT in Egyptian females.

Natural Autoimmunity to Selenoprotein P Impairs Selenium Transport in Hashimoto's Thyroiditis

The essential trace element selenium (Se) is needed for the biosynthesis of selenocysteine-containing selenoproteins, including the secreted enzyme glutathione peroxidase 3 (GPX3) and the Se-transporter selenoprotein P (SELENOP). Both are found in blood and thyroid colloid, where they serve protective functions. Serum SELENOP derives mainly from hepatocytes, whereas the kidney contributes most serum GPX3. Studies using transgenic mice indicated that renal GPX3 biosynthesis depends on Se supply by hepatic SELENOP, which is produced in protein variants with varying Se contents. Low Se status is an established risk factor for autoimmune thyroid disease, and thyroid autoimmunity generates novel autoantigens. We hypothesized that natural autoantibodies to SELENOP are prevalent in thyroid patients, impair Se transport, and negatively affect GPX3 biosynthesis. Using a newly established quantitative immunoassay, SELENOP autoantibodies were particularly prevalent in Hashimoto’s thyroiditis as compared with healthy control subjects (6.6% versus 0.3%). Serum samples rich in SELENOP autoantibodies displayed relatively high total Se and SELENOP concentrations in comparison with autoantibody-negative samples ([Se]; 85.3 vs. 77.1 µg/L, p = 0.0178, and [SELENOP]; 5.1 vs. 3.5 mg/L, p = 0.001), while GPX3 activity was low and correlated inversely to SELENOP autoantibody concentrations. In renal cells in culture, antibodies to SELENOP inhibited Se uptake. Our results indicate an impairment of SELENOP-dependent Se transport by natural SELENOP autoantibodies, suggesting that the characterization of health risk from Se deficiency may need to include autoimmunity to SELENOP as additional biomarker of Se status.

The Influence of Oxidative Stress on Thyroid Diseases

Thyroid diseases, including neoplasms, autoimmune diseases and thyroid dysfunctions, are becoming a serious social problem with rapidly increasing prevalence. The latter is increasingly linked to oxidative stress. There are many methods for determining the biomarkers of oxidative stress, making it possible to evaluate the oxidative profile in patients with thyroid diseases compared to the healthy population. This opens up a new perspective for investigating the role of elevated parameters of oxidative stress and damage in people with thyroid diseases, especially of neoplastic nature. An imbalance between oxidants and antioxidants is observed at different stages and in different types of thyroid diseases. The organ, which is part of the endocrine system, uses free radicals (reactive oxygen species, ROS) to produce hormones. Thyroid cells release enzymes that catalyse ROS generation; therefore, a key role is played by the internal defence system and non-enzymatic antioxidants that counteract excess ROS not utilised to produce thyroid hormones, acting as a buffer to neutralise free radicals and ensure whole-body homeostasis. An excess of free radicals causes structural cell damage, undermining genomic stability. Looking at the negative effects of ROS accumulation, oxidative stress appears to be implicated in both the initiation and progression of carcinogenesis. The aim of this review is to investigate the oxidation background of thyroid diseases and to summarise the links between redox imbalance and thyroid dysfunction and disease.

Iodine nutrition optimization: are there risks for thyroid autoimmunity?

Iodine deficiency is still the main cause of preventable thyroid disorders, worldwide. To optimize iodine intake, programs of voluntary or mandatory iodization of salt have been implemented in several iodine-deficient countries and iodine sufficiency has been achieved in many. Despite the clear beneficial effects on thyroid health, some concerns have been raised on the presumed detriment of iodine prophylaxis on thyroid autoimmunity. Very recent studies aimed at evaluating the long-term consequences of iodine supplementation on thyroid autoimmunity and related dysfunction, have clearly demonstrated that the early post-iodization increase in thyroid antibody positivity is largely transient and not clinically relevant, since the prevalence of overt thyroid dysfunction has remained reassuring low over two decades. The recommended iodine intake is therefore safe with regard to thyroid autoimmunity, the benefits largely outweighing the risks in a population with a stable median iodine concentration not exceeding 300 μg/L. Thus, a possible increase in thyroid autoimmunity should not represent a limitation to promoting iodine supplementation in the general population, also taking into account the steady rise in prevalence of autoimmune disorders which has occurred in the last few decades because of environmental factors other than iodine.

Glutathione Participation in the Prevention of Cardiovascular Diseases

Cardiovascular diseases (CVD) (such as occlusion of the coronary arteries, hypertensive heart diseases and strokes) are diseases that generate thousands of patients with a high mortality rate worldwide. Many of these cardiovascular pathologies, during their development, generate a state of oxidative stress that leads to a deterioration in the patient's conditions associated with the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Within these reactive species we find superoxide anion (O2•-), hydroxyl radical (•OH), nitric oxide (NO•), as well as other species of non-free radicals such as hydrogen peroxide (H2O2), hypochlorous acid (HClO) and peroxynitrite (ONOO-). A molecule that actively participates in counteracting the oxidizing effect of reactive species is reduced glutathione (GSH), a tripeptide that is present in all tissues and that its synthesis and/or regeneration is very important to be able to respond to the increase in oxidizing agents. In this review, we will address the role of glutathione, its synthesis in both the heart and the liver, and its importance in preventing or reducing deleterious ROS effects in cardiovascular diseases.

In Vivo Inhibition of MicroRNA-326 in a NOD.H-2h4 Mouse Model of Autoimmune Thyroiditis

Background

Previous studies reported that various miRNAs participate in autoimmune diseases, but the potential regulatory mechanism of miRNAs in autoimmune thyroiditis (AIT) needs further exploration.

Objective

This study aimed to further verify that miR-326 contributes to AIT by regulating Th17/Treg balance through Ets-1 using lentiviral gene delivery through tail vein and thyroid injection in NOD.H-2^h4 mice.

Materials and Methods

Five-week-old NOD.H-2^h4 mice were divided randomly into tail vein and thyroid injection groups, and each received either mmu-miR-326 sponge (LV-sponge) or lentiviral vector control. Mice were divided for tail vein injection: the therapeutic LV-ctrl, therapeutic LV-sponge, prophylactic LV-ctrl, and prophylactic LV-sponge groups. The control group was fed high-iodine water without vein injection. The thyroid infiltration of lymphocytes and serum TgAb value were investigated by thyroid hematoxylin and eosin (HE) staining and ELISA, respectively. Ets-1 and lymphocyte counts were measured by RT-PCR, western blotting, and flow cytometry. The thyroid CD4⁺IL-17a⁺ cells and CD4⁺Ets-1⁺ cells were detected by immunofluorescence, and the serum cytokines were tested by ELISA.

Results

In the tail vein injection groups, the thyroid inflammatory score and serum TgAb titer were significantly lower in the LV-sponge groups than in the control and LV-ctrl groups while Ets-1 protein expression in mouse spleens was increased in the LV-sponge groups. Moreover, Th17/Treg ratio declined in the LV-sponge group and decreased significantly in the prophylactic LV-sponge group (P = 0.036) tested by flow cytometry. Immunofluorescence showed that, in LV-sponge groups, CD4⁺IL-17a⁺ cells were decreased significantly (P = 0.001), while CD4⁺Ets-1⁺ cells were increased significantly in the LV-sponge group (P = 0.029). The serum IL-17/IL-10 was decreased significantly in the LV-sponge group (P < 0.05). In the thyroid injection groups, the thyroid inflammatory score and serum TgAb titer in the LV-sponge group decreased significantly compared with those in the LV-ctrl group (P < 0.05). In addition, in LV-sponge groups, CD4⁺IL-17a⁺ cells were decreased, while CD4⁺Ets-1⁺ cells were increased significantly in the inhibition group evaluated by immunofluorescence. Moreover, tail vein injection of LV-sponge resulted in much lower TgAb levels in thyroiditis compared with thyroid injection.

Conclusion

MiR-326 targeted therapy may be a promising approach for AIT. In addition, tail vein injection may achieve a better intervention effect than thyroid injection.

Heterogeneity and Dynamics of Vasculature in the Endocrine System During Aging and Disease

The endocrine system consists of several highly vascularized glands that produce and secrete hormones to maintain body homeostasis and regulate a range of bodily functions and processes, including growth, metabolism and development. The dense and highly vascularized capillary network functions as the main transport system for hormones and regulatory factors to enable efficient endocrine function. The specialized capillary types provide the microenvironments to support stem and progenitor cells, by regulating their survival, maintenance and differentiation. Moreover, the vasculature interacts with endocrine cells supporting their endocrine function. However, the structure and niche function of vasculature in endocrine tissues remain poorly understood. Aging and endocrine disorders are associated with vascular perturbations. Understanding the cellular and molecular cues driving the disease, and age-related vascular perturbations hold potential to manage or even treat endocrine disorders and comorbidities associated with aging. This review aims to describe the structure and niche functions of the vasculature in various endocrine glands and define the vascular changes in aging and endocrine disorders.

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.

Enhanced Salivary and General Oxidative Stress in Hashimoto's Thyroiditis Women in Euthyreosis

Hashimoto’s thyroiditis (HT) is one of the most common autoimmune diseases. Although HT is inextricably linked to oxidative stress, there have been no studies assessing salivary redox homeostasis or salivary gland function in patients with HT. This study is the first to compare antioxidant defense and oxidative stress biomarkers in non-stimulated (NWS) and stimulated (SWS) whole saliva and plasma/erythrocytes of HT patients compared to controls. The study included 45 women with HT in the euthyreosis period as well as an age- and gender-matched control group. We showed that NWS secretion was significantly lower in HT patients compared to healthy controls, similar to salivary amylase activity in NWS and SWS. Catalase and peroxidase activities were considerably higher in NWS and SWS of HT patients, while the concentrations of reduced glutathione and uric acid were significantly lower in comparison with healthy subjects. Total antioxidant potential was significantly lower, while total oxidant status and the level of oxidation products of proteins (advanced glycation end products, advanced oxidation protein products) and lipids (malondialdehyde, lipid hydroperoxides) were significantly higher in NWS, SWS and plasma of HT patients. In conclusion, in both salivary glands of women with HT in euthyreosis, the ability to maintain redox homeostasis was hindered. In HT patients we observed oxidative damage to salivary proteins and lipids; thus, some biomarkers of oxidative stress may present a potential diagnostic value.

Selenium exerts protective effects against oxidative stress and cell damage in human thyrocytes and fibroblasts

PURPOSE

Selenium, incorporated into specific seleno-enzymes, is essential to proper thyroid function and protect cells from oxidative damage induced by H₂O₂ during thyroid hormone synthesis. Several studies indicated that low selenium levels are associated with thyroid autoimmunity and related disorders, but real effectiveness of selenium supplementation in such diseases is still controversial. We evaluated the effect of selenium on oxidative damage in human thyrocytes and thyroid fibroblasts in vitro.

METHODS

To induce oxidative stress, primary cultures were exposed to H₂O₂, in the presence or the absence of selenium, as either selenomethionine or selenite. We performed the following assays: cell viability, caspase-3 activity, BCL-2/BAX gene expression, DNA fragmentation, malondialdehyde levels, and glutathione peroxidase (GPx) activity measurements.

RESULTS

Thyrocytes and thyroid fibroblasts exposed to H₂O₂ and preincubated with both selenocompounds displayed a significant dose-dependent increase in cell viability compared to cells incubated with H₂O₂ alone. Pretreatment with selenomethionine and selenite significantly reduced caspase-3 activity and BAX mRNA levels and increased BCL-2 mRNA levels in a dose-dependent manner. Accordingly, H₂O₂ induced a diffuse pattern of DNA degradation and an increase in malondialdehyde levels, which was prevented by the pretreatment with both selenomethionine and selenite. Both selenocompounds induced an increase in GPx activity, suggesting that these protective effects may be, almost in part, mediated by these selenoproteins.

CONCLUSION

In human thyrocytes and fibroblasts in vitro, selenium exerts protective effects against H₂O₂ in a dose-dependent manner, being selenite effective at lower doses than selenomethionine.

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 effect of spironolactone on thyroid autoimmunity in euthyroid men with Hashimoto's thyroiditis

WHAT IS KNOWN AND OBJECTIVE

Hashimoto's thyroiditis, also referred to as autoimmune thyroiditis, is characterized by sexual dimorphism, suggesting an important role of sex hormones in its development. No interventional study has investigated whether drugs exerting antiandrogen properties affect thyroid antibody titres and thyroid function tests in subjects with autoimmune thyroiditis.

METHODS

This study included 35 levothyroxine-naïve men with euthyroid Hashimoto's thyroiditis. At the physician's discretion, 18 men were then treated with spironolactone (50-200 mg daily), while the remaining patients (n = 17) received other diuretics. Serum levels of thyrotropin, free thyroid hormones, testosterone and 25-hydroxyvitamin D, as well as titres of thyroid peroxidase and thyroglobulin, were measured at the beginning of the study and 6 months later. Based on hormone levels, constant structure parameters of thyroid homeostasis were calculated.

RESULTS AND DISCUSSION

At baseline, there was no difference between the treatment arms in terms of thyroid antibody titres, hormone levels and the calculated parameters of thyroid homeostasis. Thirty-two patients completed the study. Spironolactone increased thyroid antibody titres, decreased testosterone and 25-hydroxyvitamin D levels and reduced SPINA-GT. The drug produced a neutral effect on serum levels of thyrotropin, free thyroid hormones, Jostel's thyrotropin index and SPINA-GD. The effect of spironolactone on antibody titres correlated with treatment-induced changes in SPINA-GT, testosterone and 25-hydroxyvitamin D. No significant changes in antibody titres, hormone levels and the calculated parameters of thyroid homeostasis were observed in spironolactone-naïve men.

WHAT IS NEW AND CONCLUSION

The obtained results indicate that spironolactone may exert an unfavourable effect on progression of autoimmune thyroiditis in men.

Atorvastatin potentiates the effect of selenomethionine on thyroid autoimmunity in euthyroid women with Hashimoto's thyroiditis

OBJECTIVE

In many studies, selenium supplementation decreased serum titers of thyroid antibodies. The aim of the study was to investigate whether statin therapy determines selenium action on thyroid autoimmunity.

METHODS

This prospective case-control study enrolled 42 euthyroid women with Hashimoto's thyroiditis and normal vitamin D status, 20 of whom had been treated with atorvastatin (40 mg daily) for at least 6 months. All patients received selenomethionine (200 µg daily) for 6 months. Plasma levels of lipids, serum titers of thyroid peroxidase (TPOAb) and thyroglobulin (TgAb) antibodies, as well as serum levels of thyrotropin, free thyroid hormones, and 25-hydroxyvitamin D were determined at the beginning and at the end of the study.

RESULTS

At baseline, there were no differences between both treatment arms in plasma lipids, titers of thyroid antibodies, serum levels of thyrotropin, free thyroid hormones, and 25-hydroxyvitamin D. Selenometionine decreased titers of TPOAb (from 843 ± 228 to 562 ± 189 U/mL) and TgAb (from 795 ± 286 to 501 ± 216 U/mL) in atorvastatin-treated women, as well as titers of TPOAb (from 892 ± 247 to 705 ± 205 U/mL) and TgAb (from 810 ± 301 to 645 ± 224 U/mL) in statin-naive women. The changes in antibody titers were more pronounced in women receiving atorvastatin (between-group difference: 94 [32-156] [TPOAb]; 129 [52-206] [TgAb]). Treatment-induced changes in TPOAb and TgAb correlated positively with baseline thyroid antibody titers. Circulating levels of lipids, free thyroxine, free triiodothyronine, and 25-hydroxyvitamin D remained at similar levels throughout the study.

CONCLUSIONS

The obtained results indicate that the decrease in titers of thyroid antibodies was potentiated by atorvastatin use.

HPT axis‑independent TSHβ splice variant regulates the synthesis of thyroid hormone in mice

Thyroid stimulating hormone (TSH) consists of an α‑subunit and a unique β‑subunit. The first in‑frame TSHβ splice variant produced by the cells of immune system was identified in 2009. The TSHβ splice variant and native TSHβ exhibit different expression profiles, and research has been conducted to elucidate the role of the TSHβ splice variant in different diseases. However, understanding of the fundamental physiological characteristics of the TSHβ splice variant is currently limited. To verify whether the TSHβ splice variant has the potential to induce thyroid follicular cells to synthesize thyroid hormone, in vivo and in vitro stimulation experiments were conducted in the present study. A total of 60 C57BL/6 mice were divided into control‑, 5 and 10 µg TSHβ splice variant‑treated groups at random. Mice were sacrificed at 0.5, 1 and 4 h after intraperitoneal injection, and serum levels of tri‑iodothyronine (T3) and thyroxine (T4) were determined using a radioimmunoassay. Thyroid follicular cells were isolated from the thyroids of mice, and stimulated with 2 µg/ml TSHβ splice variant. Supernatants were collected, and the levels of T3 and T4 were detected. The protein expression levels of the sodium‑iodide symporter, thyroperoxidase and thyroglobulin in thyroid follicular cells were quantified using western blot analysis. To verify whether the TSHβ splice variant expression was regulated by the hypothalamus‑pituitary‑thyroid (HPT) axis, similar to native TSHβ, a total of 60 C57BL/6 mice were equally divided into control, 2 mg/kg T3 intraperitoneal injection and 0.05 mg/kg thyroid‑releasing hormone intraperitoneal injection groups at random. Mice were sacrificed at 1 and 4 h after injection. Alterations in the expression of the TSHβ splice variant in the pituitary, thyroid, peripheral blood leukocytes and spleen tissues were detected using western blot analysis. The present study demonstrated that the TSHβ splice variant is not regulated by the HPT axis and may affect thyroid hormone synthesis. Modifications in the expression of the TSHβ splice variant may occur in a uniquely regulated manner to provide peripheral immunological compartments with a source of activated cells, particularly under immune stress.

Excess iodine intake: sources, assessment, and effects on thyroid function

Iodine is essential for thyroid hormone synthesis. High iodine intakes are well tolerated by most healthy individuals, but in some people, excess iodine intakes may precipitate hyperthyroidism, hypothyroidism, goiter, and/or thyroid autoimmunity. Individuals with preexisting thyroid disease or those previously exposed to iodine deficiency may be more susceptible to thyroid disorders due to an increase in iodine intake, in some cases at intakes only slightly above physiological needs. Thyroid dysfunction due to excess iodine intake is usually mild and transient, but iodine-induced hyperthyroidism can be life-threatening in some individuals. At the population level, excess iodine intakes may arise from consumption of overiodized salt, drinking water, animal milk rich in iodine, certain seaweeds, iodine-containing dietary supplements, and from a combination of these sources. The median urinary iodine concentration (UIC) of a population reflects the total iodine intake from all sources and can accurately identify populations with excessive iodine intakes. Our review describes the association between excess iodine intake and thyroid function. We outline potential sources of excess iodine intake and the physiological responses and consequences of excess iodine intakes. We provide guidance on choice of biomarkers to assess iodine intake, with an emphasis on the UIC and thyroglobulin.

DINP aggravates autoimmune thyroid disease through activation of the Akt/mTOR pathway and suppression of autophagy in Wistar rats

Di-isononyl phthalate (DINP) is used as a substitute for traditional phthalates, in a wide range of applications. However, there is growing concern regarding its toxicity. Studies have indicated that DINP is related to thyroid hormone disorder and that phthalates can affect thyroid normal function. In this study, we aim to determine any effects of DINP exposure on autoimmune thyroid disease (AITD), the most common autoimmune disease, and to understand the underlying causal mechanism. AITD model Wistar rats were exposed to 0.15 mg/kg, 1.5 mg/kg or 15 mg/kg DINP. We assessed the thyroid globulin antibody levels, Th1/Th2 balance, histopathological changes and caspase-3 levels in the thyroid. The data show that exposure to DINP does indeed aggravate AITD. To explore the underlying mechanisms, we examined the levels of microtubule-associated protein 1 light chain 3 B (LC3B), Sequestosome 1 (SQSTM1) and the appearance of autophagosomes or autolysosomes to assess autophagy in the thyroid. The results show that DINP can suppress normal autophagy. We found that DINP induced an exacerbation of oxidative stress and the activation of the Akt/mTOR pathway, indicating that oxidative stress and activation of mTOR may play a key role in these processes. Moreover, the activation of mTOR also promoted the expression of IL-17. Importantly, blocking oxidative stress with VE or blocking Akt/mTOR with rapamycin mitigated the exacerbation of AITD and the suppression of normal autophagy. All these results indicate that exposure to DINP, especially high doses of DINP, can aggravate oxidative stress and activate the Akt/mTOR pathway. This exposure then leads to a suppression of normal autophagy and expression of IL-17 in the thyroid, resulting in an eventual exacerbation of AITD.

Resistance to lysosomotropic drugs used to treat kidney and breast cancers involves autophagy and inflammation and converges in inducing CXCL5

Lysosomotropic agents such as sunitinib, lapatinib, and chloroquine belong to a drug family that is being used more frequently to treat advanced cancers. Sunitinib is standard care for metastatic renal cell carcinomas (mRCC) and lapatinib is used for trastuzumab/pertuzumab-refractory cancers. However, patients ineluctably relapse with a delay varying from a few months to a few years. To improve reactivity prior to relapse it is essential to identify the mechanisms leading to such variability. We showed previously that sunitinib became sequestered in lysosomes because of its basic pKa.

Methods: Modifications to gene expression in response to sunitinib and in sunitinib resistant cells were analyzed by transcriptomic and proteomic analysis. ROS production was evaluated by FACS. Nuclear Factor kappa B (NFkB)-dependent transcriptional regulation of inflammatory gene expression was evaluated with a reporter gene. Correlation of CXCL5 with survival was analyzed with an online available data base (TCGA) and using a cohort of patients enrolled in the SUVEGIL clinical trial (NCT00943839).

Results: We now show that sunitinib sequestration in lysosomes induced an incomplete autophagic process leading to activation of the NFkB inflammatory pathway. We defined a subset of inflammatory cytokines that were up-regulated by the drug either after an acute or chronic stimulus. One of the most up-regulated genes in sunitinib-resistant cells was the CXCL5 cytokine. CXCL5 was also induced in RCC by chloroquine and in a model of HER2 positive breast cancer cell lines after acute or chronic treatment with lapatinib. CXCL5 correlated to shorter survival in RCC and to the most aggressive forms of breast cancers. The levels of CXCL5 present in the plasma of patients treated with sunitinib were predictive of the efficacy of sunitinib but not of the VEGF-directed antibody bevacizumab.

Conclusion: This translational study identified CXCL5 as a biomarker of efficacy of lysosomotropic drugs, a potential asset for personalized medicine.

Sexual Dimorphism of NADPH Oxidase/H₂O₂ System in Rat Thyroid Cells; Effect of Exogenous 17β-Estradiol

It has long been observed that females are more susceptible to thyroid diseases than males. Epidemiological and experimental data show that actions of hormonal factors—especially estrogens—may explain such disparity. However, the exact cause and mechanisms of this sexual dimorphism remain so far unknown. Therefore, we aimed at evaluating the effect of 17β-estradiol on the redox balance in thyroids of male and female rats. Expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, i.e., dual oxidase 1 (DUOX1), dual oxidase 2 (DUOX2) and NADPH oxidase 4 (NOX4), and hydrogen peroxide (H₂O₂) levels were evaluated in the primary cell cultures derived from thyroid glands of adult male or female Wistar rats. The measurement was made before and after treatment with 17β-estradiol alone or with addition of one of its receptor antagonists. We found that under basal conditions female thyroid cells are exposed to higher concentrations of H₂O₂, most likely due to NOX/DUOX enzymes activity. Additionally, exogenous 17β-estradiol stimulated NOX/DUOX expression as well as H₂O₂ production, and this effect was mainly mediated through ERα. In conclusion, oxidative processes may constitute mechanisms responsible for sexual dimorphism of thyroid diseases. Exogenous 17β-estradiol may play a crucial pathogenic role in thyroid diseases via oxidative mechanisms, however without any gender differences.

The effect of oxidative stress on the progression of Hashimoto's thyroiditis

OBJECTIVE

We aimed to investigate the effects of oxidative stress in the pathogenesis and progression of Hashimoto's thyroiditis (HT).

METHODS

Forty euthyroid and 40 subclinical hypothyroid patients older than 18 years and not yet had received treatment were enrolled in the study.

RESULTS

In the 9 months follow-up, 14 of the HT patients developed overt hypothyroidism. The mean total oxidant status (TOS) and oxidative stress index (OSI) were higher in patients who developed overt hypothyroidism than those who did not (p < .001). And no significant difference was found between the two groups in terms of paraoxanase-1 and arylesterase (p > .05). Multivariable Cox regression model showed thyroid stimulating hormone level (HR = 1.348, p < .001), free-thyroxine level (HR = 0.481, p = .017) and OSI ratio (HR = 2.349, p < .001) to be independent predictors of development of overt hypothyroidism. OSI level, being over 2.96 with 92.9% sensitivity and 62.5% specificity, predicts the risk of hypothyroidism.

CONCLUSION

Oxidative stress may be an effective risk factor in the development of overt hypothyroidism in HT.

The catalytic role of iodine excess in loss of homeostasis in autoimmune thyroiditis

PURPOSE OF REVIEW

To review the latest developments concerning the role of iodine in the pathophysiology of autoimmune thyroiditis.

RECENT FINDINGS

Recent studies have provided evidence that in areas with excess iodine intake, increased incidence of autoimmune thyroiditis marked by high titers of thyroid peroxidase and thyroglobulin antibodies has occurred. Investigations in the NOD.H2h4 mouse, a strain prone to AIT, showed that they are better adapted to the Wolff-Chaikoff effect.

SUMMARY

To provide an overview of the studies conducted during the last few years implicating iodine in the development and manifestation of autoimmune thyroiditis.

Nitric oxide is involved in the hypothyroidism with significant morphology changes in female Wistar rats induced by chronic exposure to high water iodine from potassium iodate

Epidemiological studies indicated that chronic exposure to high water iodine is associated with primary hypothyroidism (PH) and subclinical hypothyroidism (SCH). However, the mechanism is not well understood. In this study, we explored whether chronic exposure to high water iodine from potassium iodate (KIO₃) can induce hypothyroidism in addition to determining if nitric oxide (NO) is involved in the pathogenesis. 96 female Wistar rats were divided into six groups: control, I_1000μg/L, I_3000μg/L, I_6000μg/L, N-nitro-L-arginine methylester (L-NAME) and L-NAME+I_6000μg/L. After 3 months, urine iodine concentration, thyroid hormone, NO and nitric oxide synthase (NOS) serum levels were determined. Additionally, thyroid expression of inducible nitric oxide synthase (iNOS) was also investigated. Thyroid morphology was observed under light microscopy and transmission electron microscope. SCH as indicated by elevated serum thyrotropin (TSH) was induced among rats exposed to 3000 μg/L I^-, while rats treated with 6000 μg/L I^- presented PH characterized by elevated TSH and lowered total thyroxine in serum. Moreover, serum NO, NOS and iNOS expression in the thyroid were significantly increased in I_3000μg/L and I_6000μg/L groups. Changes in thyroid function and morphology in the L-NAME+I_6000μg/L group were extenuated compared to I_6000μg/L group. These findings suggested that chronic exposure to high water iodine from KIO₃ likely induces hypothyroidism with significant morphology changes in female Wistar rats and NO appears to be involved in the pathogenesis.

Vitamin C deficiency aggravates tumor necrosis factor α-induced insulin resistance

Chronic low-grade inflammation plays a major role in the development of insulin resistance. The potential role and underlying mechanism of vitamin C, an antioxidant and anti-inflammatory agent, was investigated in tumor necrosis factor-α (TNF-α)-induced insulin resistance. Gulonolactone oxidase knockout (Gulo^-/-) mice genetically unable to synthesize vitamin C were used to induce insulin resistance by continuously pumping small doses of TNF-α for seven days, and human liver hepatocellular carcinoma cells (HepG2 cells) were used to induce insulin resistance by treatment with TNF-α. Vitamin C deficiency aggravated TNF-α-induced insulin resistance in Gulo^-/- mice, resulting in worse glucose tolerance test (GTT) results, higher fasting plasma insulin level, and the inactivation of the protein kinase B (AKT)/glycogen synthase kinase-3β (GSK3β) pathway in the liver. Vitamin C deficiency also worsened liver lipid accumulation and inflammation in TNF-α-treated Gulo^-/- mice. In HepG2 cells, vitamin C reversed the TNF-α-induced reduction of glucose uptake and glycogen synthesis, which were mediated by increasing GLUT2 levels and the activation of the insulin receptor substrate (IRS-1)/AKT/GSK3β pathway. Furthermore, vitamin C inhibited the TNF-α-induced activation of not only the mitogen-activated protein kinase (MAPKs), but also nuclear factor-kappa B (NF-κB) signaling. Taken together, vitamin C is essential for preventing and improving insulin resistance, and the supplementing with vitamin C may be an effective therapeutic intervention for metabolic disorders.

Evaluation of hypothalamus-pituitary-thyroid axis function by chronic perchlorate exposure in male rats

Perchlorate is a widespread endocrine disruptor that was previously correlated with increased serum TSH levels and decreased thyroid hormones production both in animals and humans. Even so, the regulation of gene/protein expression in the hypothalamus, pituitary and thyroid by chronic perchlorate exposure was not completely elucidated. Therefore, this study aimed to investigate the underlying mechanisms involved in the disruption of hypothalamus-pituitary-thyroid axis by chronic perchlorate exposure. Male Wistar rats were treated or not with NaClO₄ in the drinking water (35 mg/Kg/day) for 60 days. Thereafter, hormone/cytokines serum levels were measured through multiplex assays; genes/proteins expression were investigated by qPCR/Western Blotting and thyroid morphology was evaluated through histological analysis. Serum TSH levels were increased and serum T₄ /T₃ levels were decreased in perchlorate-treated animals. This treatment also altered the thyrotropin-releasing hormone mRNA/protein content in the hypothalamus. Additionally, the expression of both subunits of TSH were increased in the pituitary of perchlorate-treated rats, which also presented significant alterations in the thyroid morphology/gene expression. Furthermore, perchlorate exposure reduced liver Dio1 mRNA expression and increased the content of pro-inflammatory cytokines in the thyroid and the serum. In conclusion, our study adds novel findings about the perchlorate-induced disruption of the hypothalamus-pituitary-thyroid axis gene/protein expression in male rats. The data presented herein also suggest that perchlorate induces thyroid and systemic inflammation through the increased production of cytokines. Taken together, our results suggest that perchlorate contamination should be monitored, especially in the individuals most susceptible to the deleterious effects of reduced levels of thyroid hormones.

Increased Interleukin-23 in Hashimoto's Thyroiditis Disease Induces Autophagy Suppression and Reactive Oxygen Species Accumulation

Hashimoto’s thyroiditis (HT) represents the most common organ-specific autoimmune disease. Inflammatory factors and reactive oxygen species (ROS) play detrimental roles during the pathogenesis of HT. In this study, we found that thyroid follicular cells (TFCs) from HT patients expressed an elevated level of interleukin-23 (IL-23), which contributed to autophagy suppression and ROS accumulation. Additionally, IL-23-induced autophagy suppression and ROS accumulation in human TFCs was attributed to AKT/mTOR/NF-κB signaling pathway activation. Inhibition of either IL-23 by a specific neutralization antibody, or mTOR by rapamycin, or NF-κB by IKK-16, significantly reversed the autophagy suppression and ROS accumulation. These results demonstrate a key role for IL-23 in HT pathogenesis and provide a potential therapeutic strategy against IL-23 or its signaling pathway in HT.

Dynamic Thiol/Disulphide Homeostasis in Children and Adolescents with Non-Autoimmune Subclinical Hypothyroidism

OBJECTIVE

To evaluate the thiol/disulphide homeostasis in children with non-autoimmune subclinical hypothyroidism (SHT).

SUBJECTS AND METHODS

Thiol/disulphide homeosta sis, involving native thiol (SH), disulphide (SS), and total thiol (SS + SH), was evaluated in 60 children and adolescents who were negative for thyroid auto-antibodies (anti-thyroid peroxidase, anti-thyroglobulin) and had a thyroid-stimulating hormone (TSH) value of > 5 mIU/L, and in 40 sex- and age-matched healthy control subjects who were negative for thyroid autoantibodies and had normal TSH levels. Lipid profiles and urine iodine levels were also determined.

RESULTS

SH (466 ± 32.8 vs. 462 ± 32.1 μmol/L p = 0.59), SH + SS (508 ± 34.0 vs. 506 ± 32.7 μmol/L, p = 0.81), SS (21 ± 5.5 vs. 22 ± 5.8 μmol/L, p = 0.41), SS/SH (4.5 ± 1.2 vs. 4.8 ± 1.3%, p = 0.36), SS/SH + SS (4.1 ± 1.0 vs. 4.3 ± 1.1%, p = 0.36) and SH/SH + SS (91 ± 2.1 vs. 91 ± 2.1%, p = 0.31) levels were similar in children with SHT and control subjects (p > 0.05). There was no difference between total cholesterol, triglyceride, and low-density lipoprotein levels in SHT patients and controls. No difference was detected between the patients with or without iodine deficiency in the SHT group in terms of thiol/disulphide homeostasis parameters.

CONCLUSION

The status of dynamic thiol/disulphide homeostasis did not change in children and adolescents with non-autoimmune SHT. Future studies are needed for the evaluation of oxidative stress in patients with long-standing non-autoimmune SHT.

Oral exposure to dibutyl phthalate exacerbates chronic lymphocytic thyroiditis through oxidative stress in female Wistar rats

Chronic lymphocytic thyroiditis (CLT) is a common autoimmune disorder. The possible pathogenic role and mechanism of dibutyl phthalate (DBP) in CLT is still controversial. Experiments were conducted after 35-days of oral exposure to the three concentrations of DBP or saline, and three immunizations with thyroglobulin (TG). Healthy female Wistar rats were randomly divided into ten exposure groups (n = 8 each): (A) saline control, (B) 0.5 mg/kg/d DBP, (C) 5 mg/kg/d DBP, (D) 50 mg/kg/d DBP, (E) TG-immunized group, (F) TG- combined with 0.5 mg/kg/d DBP, (G) TG- combined with 5 mg/kg/d DBP, (H) TG- combined with 50 mg/kg/d DBP, (I) TG- combined with 50 mg/kg/d DBP plus 100 mg/kg/d vitamin C; (J) 100 mg/kg/d vitamin C. We showed that oral exposure DBP can aggravate CLT in rats. This deterioration was concomitant with increased thyroid auto antibodies, Th1/Th2 imbalance and Th17 immune response, activated pro-inflammatory and apoptosis pathways, and increased thyroid dysfunction in rats. Our results also suggested that DBP could promote oxidative damage. The study also found that vitamin C reduced the levels of oxidative stress and alleviated CLT. In short, the study showed that DBP exacerbated CLT through oxidative stress.

Iodine excess exposure during pregnancy and lactation impairs maternal thyroid function in rats

Adequate maternal iodine consumption during pregnancy and lactation guarantees normal thyroid hormones (TH) production, which is crucial to the development of the fetus. Indeed, iodine deficiency is clearly related to maternal hypothyroidism and deleterious effects in the fetal development. Conversely, the effects of iodine excess (IE) consumption on maternal thyroid function are still controversial. Therefore, this study aimed to investigate the impact of IE exposure during pregnancy and lactation periods on maternal hypothalamus-pituitary-thyroid axis. IE-exposed dams presented reduced serum TH concentration and increased serum thyrotropin (TSH) levels. Moreover, maternal IE exposure increased the hypothalamic expression of Trh and the pituitary expression of Trhr, Dio2, Tsha and Tshb mRNA, while reduced the Gh mRNA content. Additionally, IE-exposed dams presented thyroid morphological alterations, increased thyroid oxidative stress and decreased expression of thyroid genes/proteins involved in TH synthesis, secretion and metabolism. Furthermore, Dio1 mRNA expression and D1 activity were reduced in the liver and the kidney of IE-treated animals. Finally, the mRNA expression of Slc5a5 and Slc26a4 were reduced in the mammary gland of IE-exposed rats. The latter results are in accordance with the reduction of prolactin expression and serum levels in IE-treated dams. In summary, our study indicates that the exposure to IE during pregnancy and lactation induces primary hypothyroidism in rat dams and impairs iodide transfer to the milk.

MECHANISMS IN ENDOCRINOLOGY: Aging and anti-aging: a Combo-Endocrinology overview

Aging and its underlying pathophysiological background has always attracted the attention of the scientific society. Defined as the gradual, time-dependent, heterogeneous decline of physiological functions, aging is orchestrated by a plethora of molecular mechanisms, which vividly interact to alter body homeostasis. The ability of an organism to adjust to these alterations, in conjunction with the dynamic effect of various environmental stimuli across lifespan, promotes longevity, frailty or disease. Endocrine function undergoes major changes during aging, as well. Specifically, alterations in hormonal networks and concomitant hormonal deficits/excess, augmented by poor sensitivity of tissues to their action, take place. As hypothalamic-pituitary unit is the central regulator of crucial body functions, these alterations can be translated in significant clinical sequelae that can impair the quality of life and promote frailty and disease. Delineating the hormonal signaling alterations that occur across lifespan and exploring possible remedial interventions could possibly help us improve the quality of life of the elderly and promote longevity.

Changes in the DNA Methylation and Hydroxymethylation Status of the Intercellular Adhesion Molecule 1 Gene Promoter in Thyrocytes from Autoimmune Thyroiditis Patients

BACKGROUND

The intercellular adhesion molecule 1 (ICAM1) gene is not expressed in normal thyroid tissue but was shown to be expressed in the thyroid tissue of autoimmune thyroiditis (AIT) patients.

METHODS

This study aimed to explore whether the DNA methylation and hydroxymethylation status of the ICAM1 promoter are aberrantly altered in the thyroid cells of AIT patients and whether this change is associated with dysfunctional expression of ICAM1. A total of 35 AIT patients and 35 sex- and age-matched controls were studied. After the isolation of thyrocytes via density-gradient centrifugation, ICAM1 mRNA expression was measured using real-time PCR. The DNA methylation and hydroxymethylation status were assessed using quantitative PCR following T4 β-glucosyltransferase treatment and MspI/HpaII cleavage at -937 bp, -701 bp, -226 bp, and -65 bp upstream of the transcription start site (TSS). The DNA methylation level was verified via pyrosequencing.

RESULTS

The AIT group showed increased DNA hydroxymethylation at -937 bp and -226 bp and decreased methylation at -937 bp, -701 bp, and -226 bp upstream of the TSS. Pyrosequencing also revealed DNA hypomethylation at -708 bp, -692 bp, -690 bp, and -688 bp upstream of the TSS. The DNA methylation status at -708 bp, -692 bp, and -226 bp upstream of the TSS was negatively associated with ICAM1 mRNA expression.

CONCLUSION

In summary, we identified aberrant DNA methylation and hydroxymethylation of the ICAM1 gene promoter in the thyrocytes of AIT patients. This aberrant epigenetic modification is associated with increased expression of the ICAM1 gene.

Thiol/disulphide homeostasis in celiac disease

AIM

To determine dynamic thiol/disulphide homeostasis in celiac disease and to examine the associate with celiac autoantibodies and gluten-free diet.

METHODS

Seventy three patients with celiac disease and 73 healthy volunteers were enrolled in the study. In both groups, thiol/disulphide homeostasis was examined with a new colorimetric method recently developed by Erel and Neselioglu.

RESULTS

In patients with celiac disease, native thiol (P = 0.027) and total thiol (P = 0.031) levels were lower, while disulphide (P < 0.001) level, disulphide/native thiol (P < 0.001) and disulphide/total thiol (P < 0.001) ratios were higher compared to the control group. In patients who do not comply with a gluten-free diet, disulphide/native thiol ratio was found higher compared to the patients who comply with the diet (P < 0.001). In patients with any autoantibody-positive, disulphide/native thiol ratio was observed higher compared to the patients with autoantibody-negative (P < 0.05). It is found that there is a negative correlation between celiac autoantibodies, and native thiol, total thiol levels and native thiol/total thiol ratio, while a positive correlation is observed between disulphide, disulphide/native thiol and disulphide/total thiol levels.

CONCLUSION

This study is first in the literature which found that the patients with celiac disease the dynamic thiol/disulphide balance shifts through disulphide form compared to the control group.

Thyroid hormones in extreme longevity

The aim of the present review was to summarize knowledge about thyroid hormones (THs) and longevity. Longevity is a complex multifactorial phenomenon on which specific biological pathways, including hormonal networks involved in the regulation of homeostasis and survival, exert a strong impact. THs are the key responsible for growth, metabolism rate and energy expenditure, and help in maintaining cognition, bone and cardiovascular health. THs production and metabolism are fine tuned, and may help the organism to cope with a variety of environmental challenges. Experimental evidence suggests that hypothyroid state may favor longevity by reducing metabolism rate, oxidative stress and cell senescence. Data from human studies involving healthy subjects and centenarians seem to confirm this view, but THs changes observed in older patients affected by chronic diseases cannot be always interpreted as a protective adaptive mechanism aimed at reducing catabolism and prolonging survival. Medications, selected chronic diseases and multi-morbidity can interfere with thyroid function, and their impact is still to be elucidated.

Overexpression of Interleukin-4 in the Thyroid of Transgenic Mice Upregulates the Expression of Duox1 and the Anion Transporter Pendrin

BACKGROUND

The dual oxidases (Duox) are involved in hydrogen peroxide generation, which is essential for thyroid hormone synthesis, and therefore they are markers of thyroid function. During inflammation, cytokines upregulate DUOX gene expression in the airway and the intestine, suggesting a role for these proteins in innate immunity. It was previously demonstrated that interleukin-4 (IL-4) upregulates DUOX gene expression in thyrocytes. Although the role of IL-4 in autoimmune thyroid diseases has been studied extensively, the effects of IL-4 on thyroid physiology remain largely unknown. Therefore, a new animal model was generated to study the impact of IL-4 on thyroid function.

METHODS

Transgenic (Thyr-IL-4) mice with thyroid-targeted expression of murine IL-4 were generated. Transgene expression was verified at the mRNA and protein level in thyroid tissues and primary cultures. The phenotype of the Thyr-IL-4 animals was characterized by measuring serum thyroxine (T4) and thyrotropin levels and performing thyroid morphometric analysis, immunohistochemistry, whole transcriptome sequencing, quantitative reverse transcription polymerase chain reaction, and ex vivo thyroid function assays.

RESULTS

Thyrocytes from two Thyr-IL-4 mouse lines (#30 and #52) expressed IL-4, which was secreted into the extracellular space. Although 10-month-old transgenic animals had T4 and thyrotropin serum levels in the normal range, they had altered thyroid follicular structure with enlarged follicles composed of elongated thyrocytes containing numerous endocytic vesicles. These follicles were positive for T4 staining the colloid, indicating their capacity to produce thyroid hormones. RNA profiling of Thyr-IL-4 thyroid samples revealed modulation of multiple genes involved in inflammation, while no major leukocyte infiltration could be detected. Upregulated expression of Duox1, Duoxa1, and the pendrin anion exchanger gene (Slc26a4) was detected. In contrast, the iodide symporter gene Slc5a5 was markedly downregulated resulting in impaired iodide uptake and reduced thyroid hormone levels in transgenic thyroid tissue. Hydrogen peroxide production was increased in Thyr-IL-4 thyroid tissue compared with wild-type animals, but no significant oxidative stress could be detected.

CONCLUSIONS

This is the first study to show that ectopic expression of IL-4 in thyroid tissue upregulates Duox1/Duoxa1 and Slc26a4 expression in the thyroid. The present data demonstrate that IL-4 could affect thyroid morphology and function, mainly by downregulating Slc5a5 expression, while maintaining a normal euthyroid phenotype.

Cellular stress and innate inflammation in organ-specific autoimmunity: lessons learned from vitiligo

For decades, research in autoimmunity has focused primarily on immune contributions to disease. Yet recent studies report elevated levels of reactive oxygen species and abnormal activation of the unfolded protein response in cells targeted by autoimmunity, implicating cellular stress originating from the target tissue as a contributing factor. A better understanding of this contribution may help to answer important lingering questions in organ-specific autoimmunity, as to what factors initiate disease and what directs its tissue specificity. Vitiligo, an autoimmune disease of the skin, has been the focus of translational research for over 30 years, and both melanocyte stress and immune mechanisms have been thought to be mutually exclusive explanations for pathogenesis. Chemical-induced vitiligo is a unique clinical presentation that reflects the importance of environmental influences on autoimmunity, provides insight into a new paradigm linking cell stress to the immune response, and serves as a template for other autoimmune diseases. In this review, I will discuss the evidence for cell stress contributions to a number of autoimmune diseases, the questions that remain, and how vitiligo, an underappreciated example of organ-specific autoimmunity, helps to answer them.

Reactive oxygen species in organ-specific autoimmunity

Reactive oxygen species (ROS) have been extensively studied in the induction of inflammation and tissue damage, especially as it relates to aging. In more recent years, ROS have been implicated in the pathogenesis of autoimmune diseases. Here, ROS accumulation leads to apoptosis and autoantigen structural changes that result in novel specificities. ROS have been implicated not only in the initiation of the autoimmune response but also in its amplification and spreading to novel epitopes, through the unmasking of cryptic determinants. This review will examine the contribution of ROS to the pathogenesis of four organ specific autoimmune diseases (Hashimoto thyroiditis, inflammatory bowel disease, multiple sclerosis, and vitiligo), and compare it to that of a better characterized systemic autoimmune disease (rheumatoid arthritis). It will also discuss tobacco smoking as an environmental factor endowed with both pro-oxidant and anti-oxidant properties, thus capable of differentially modulating the autoimmune response.

The impact of levothyroxine sodium treatment on oxidative stress in Hashimoto's thyroiditis

OBJECTIVE

Although several studies reported increased oxidative stress in Hashimoto's thyroiditis (HT), the effect of levothyroxine treatment on oxidative status is not studied extensively. Therefore, we conducted this study to investigate the effects of levothyroxine replacement on oxidative stress in HT.

DESIGN AND METHODS

Thirty-six patients recently diagnosed with HT-related hypothyroidism and 36 healthy controls were included in the study. Levothyroxine replacement was started to patients with hypothyroidism, and had been followed-up for 6 months.

RESULTS

Mean basal serum total antioxidant status (TAS), total thiol, arylesterase, and paraoxonase 1 (PON1) levels were significantly lower, and serum total oxidant status (TOS) and oxidative stress index (OSI) were significantly higher in the patients with hypothyroid than the controls. In the hypothyroid group serum TAS, total thiol, arylesterase, and PON1 levels increased and serum TOS and OSI levels decreased significantly after levothyroxine treatment. Pretreatment serum TAS, total thiol, PON1, and arylesterase levels were positively correlated with free levothyroxine (fT4) and negatively correlated with thyroid-stimulating hormone (TSH), antithyroid peroxidase (anti-TPO), and antithyroglobulin (anti-TG) levels. Also, pretreatment serum TOS and OSI levels were negatively correlated with fT4 levels and positively correlated with TSH, anti-TPO, and anti-TG. We have also found that the fT4 and anti-TPO levels are independent predictors of the oxidative stress parameters in stepwise multivariable linear regression analysis.

CONCLUSION

This study suggests that levothyroxine replacement decreases oxidant status and increases antioxidant status following the 6 months of levothyroxine replacement in hypothyroidism that develops in accordance with the HT.

Genomics and phenomics of Hashimoto's thyroiditis in children and adolescents: a prospective study from Southern India

BACKGROUND

Hashimoto's thyroiditis (HT) is the commonest cause of acquired hypothyroidism in children and adolescents in iodine non-endemic areas. The genetic analysis in HT shows two types of susceptibility genes-immune regulatory and thyroid specific genes. The exact genotype-phenotypic correlations and risk categorization of hypothyroid phenotypes resulting from these known mutations are largely speculative. The genetic studies in pediatric HT are very sparse from Indian sub-continent. In this context, we analysed the prevalence of TPO, NIS and DUOX2 gene mutations along with genotype-phenotype correlations in hypothyroid children with HT.

METHODS

This is inter-disciplinary study conducted by collaboration between a tertiary care endocrinology hospital, biochemistry department of a teaching medical institute and genetics lab. In this prospective study, we employed 8 sets of primers and screened for 142 known single nucleotide polymorphisms in TPO, NIS, DUOX2 genes. The subjects were children and adolescents with hypothyroidism due to HT. Congenital hypothyroidism, iodine deficiency and dyshormonogenetic hypothyroidism cases were excluded.

RESULTS

We detected 8 mutations in 7/20 (35%) children in the entire cohort (6 in NIS and 2 in TPO genes. No mutations were observed in DUOX2 gene. All our mutations were localized in introns and we found none in exons. Except for bi-allelic, synonymous polymorphism of TPO gene in child No. 18, all other mutations were heterozygous in nature. Genotype-phenotype correlations show that our mutations significantly expressed the presence of associated autoimmune manifestations and existence of family history. Clinical phenotypes of painful thyroiditis, severity of hypothyroidism and absence of goiter were statistically significant in the presence of these mutations. But, they could not reach significance on multivariate analysis.

CONCLUSIONS

NIS gene followed by TPO mutations appears to be most prevalent mutations in HT amongst South Indian children and these mutations significantly influenced phenotypic expressions such as severity of hypothyroidism, goiter, auto-immune manifestations and family history.

Trace elements profile is associated with insulin resistance syndrome and oxidative damage in thyroid disorders: Manganese and selenium interest in Algerian participants with dysthyroidism

The relationship between dysthyroidism and antioxidant trace elements (ATE) status is very subtle during oxidative stress (OS). This relationship is mediated by thyroid hormone (TH) disorder, insulin resistance syndrome (IRS) and inflammation. The aim of this study was to investigate ATE such as selenium (Se), manganese (Mn), zinc (Zn) and copper (Cu) status on thyroid dysfunction, and their interaction with antioxidant enzyme activities, mainly, superoxide dismutase (SOD) and glutathione peroxidase (GPx), TH profile (TSH, T(3), T(4)) and IRS clusters. The study was undertaken on 220 Algerian adults (30-50 years), including 157 women and 63 men who were divided to 4 groups: subclinical hypothyroidism (n = 50), overt hypothyroidism (n = 60), Graves's disease hyperthyroidism (n = 60) and euthyroid controls (n = 50). The IRS was confirmed according to NCEP (National Cholesterol Education Program). Insulin resistance was evaluated by HOMA-IR model. Trace elements were determined by the Flame Atomic Absorption Spectrometry (Flame-AAS) technique. The antioxidant enzymes activity and metabolic parameters were determined by biochemical methods. The TH profile and anti-Thyroperoxidase Antibodies (anti-TPO-Ab) were evaluated by radioimmunoassay. Results showed that the plasma manganese levels were significantly increased in all dysthyroidism groups (p ≤ 0.01). However, the plasma copper and zinc concentrations were maintained normal or not very disturbed vs control group. In contrast, the plasma selenium levels were highly decreased (p ≤ 0.001) and positively correlated with depletion of glutathione peroxidase activity; and associated both with anti-TPO-Ab overexpression and fulminant HS-CRP levels. This study confirms the oxidative stress-inflammation relationship in the dysthyroidism. The thyroid follicles antioxidant protection appears preserved in the cytosol (Cu/Zn-SOD), while it is altered in the mitochondria (Mn-SOD), which gives this cell organelle, a status of real target therapy in thyroid dysfunction. The publisher would like to apologise for any inconvenience caused. [corrected].