Assesment of oxidative status and its association with thyroid autoantibodies in patients with euthyroid autoimmune thyroiditis

The immune system in Hashimoto's thyroiditis: Updating the current state of knowledge on potential therapies and animal model construction

Hashimoto's thyroiditis (HT) is one of the most prevalent endocrine disorders worldwide, and it can occur in people of all ages, including children. HT has a multifactorial pathogenesis and develops after a combination of gene regulation, environmental modifiers, and infection triggers. Various coamplifying feedback chronic inflammatory systems are involved in immune mechanisms, including oxidative stress, lymphocyte infiltration, and thyroid cell death. Furthermore, there is no effective treatment for HT at their roots. Thus, this review systematically summarizes and updates the existing etiology and pathogenesis, potential malignant transformation, emerging therapeutic drugs and animal model construction, making it more convenient for researchers to obtain effective information about HT and better explore potential strategies for short-term treatment of the disease.

Dihydroartemisinin inhibits the development of autoimmune thyroiditis by modulating oxidative stress and immune imbalance

Autoimmune thyroiditis is among the most prevalent autoimmune endocrine illnesses. However, the pathophysiology has not been determined, and efficacious treatments are still lacking. The current study used network pharmacology analysis and an experimental autoimmune thyroiditis (EAT) mouse model to explore whether dihydroartemisinin (DHA) has therapeutic effects on autoimmune thyroiditis and to investigate the potentially related mechanisms concerning oxidative stress (OS) responses and T-cell immune imbalance. The therapeutic effects of DHA on autoimmune thyroiditis and potentially related processes were first anticipated using network pharmacology analysis and then verified using the EAT model. DHA may influence the onset of autoimmune thyroiditis by regulating immune imbalance and OS responses, according to network pharmacology analysis. ELISA, immunofluorescence staining, and histopathological examination were used to detect changes in serum thyroid autoantibody levels and intrathyroidal inflammatory infiltration following DHA intervention. RT-PCR was used to determine the spleen's mRNA expression of typical T-cell cytokines, whereas an OS kit and immunohistochemical staining were used to assess the thyroid's glutathione (GSH) content, superoxide dismutase (SOD) activity, and Nrf2 protein expression. Furthermore, serum TgAb levels and intrathyroidal inflammatory infiltrates were considerably lower in EAT mice given high-dose DHA than in vehicle-treated controls. In the spleen, IFN-γ, IL-17A, and IL-6 mRNA expressions were dramatically downregulated, while IL-4 and IL-10 were significantly raised. Following high-dose DHA treatment, GSH content, SOD activity, and Nrf2 protein expression levels were markedly increased in thyroid tissue. These findings imply that DHA administration may suppress TgAb formation and reduce intrathyroidal inflammatory cell infiltration by restoring T-cell immune imbalance and increasing antioxidant capacity via the Nrf2 pathway. This study provides important experimental data for DHA's therapeutic use in patients with autoimmune thyroiditis.

Association between total vitamin C intake and hypothyroidism among Hashimoto thyroiditis: National Health and Nutrition Examination Survey, 2007-2012

Oxidative stress may be involved in the progression of hypothyroidism in patients with Hashimoto thyroiditis (HT). Vitamin C is a well-known powerful antioxidant. To our knowledge, whether vitamin C intake relates to hypothyroidism in patients with HT remains unclear. In this cross-sectional study based on the National Health and Nutrition Examination Survey, 2007-2012, we aimed to explore the relationship between total vitamin C intake and hypothyroidism in patients with HT, using multivariate logistic regression models and restricted cubic spline analyses. Our results showed a significant negative linear association between total vitamin C intake (log10-transformed data) and hypothyroidism in HT. Compared with those with the lowest quartile of total vitamin C intake (log10-transformed), participants with the highest quartile were at lower odds of having hypothyroidism (adjusted OR 0·40, 95 % CI: 0·18, 0·88, Ptrend = 0·027). This association was consistent in subgroups stratified by sex (Pfor interaction = 0·084) and age (≥ 60 years and < 60 years, Pfor interaction = 0·330). This study revealed that total vitamin C intake was inversely associated with hypothyroidism among individuals with HT, indicating that higher vitamin C intakes (4·57-1258·9 mg/d) may be associated with a lower likelihood of hypothyroidism among HT participants.

The association between dietary inflammatory index and dietary total antioxidant capacity and Hashimoto's thyroiditis: a case-control study

BACKGROUND

Hashimoto's thyroiditis (HT) is an inflammatory disease characterized by increased reactive oxygen species. Diets rich in anti-inflammatory and antioxidant properties may be linked to a reduced risk of developing HT. The aim of this study was to investigate the association between the dietary inflammatory index (DII) and dietary total antioxidant capacity (DTAC) with HT in Iranian adults.

METHODS

The study was a hospital-based case-control study conducted on 230 participants (115 cases and 115 controls). Dietary intake was assessed using a food frequency questionnaire (FFQ). The FFQ data were used to calculate DII and DTAC scores. Anthropometric measurements, thyroid function, and antibody tests were evaluated using standard methods. Multivariable logistic regression analysis was performed in both raw and adjusted models to determine the association between DII and DTAC scores with HT.

RESULTS

The average age of the participants was 39.76 ± 9.52 years. The mean body mass index in the case and control groups was 28.03 ± 6.32 and 26.43 ± 5.13 (kg/m2), respectively (P = 0.036). In the HT group, the DII level was higher (P < 0.001) and the DTAC level was lower than those in the healthy group (P = 0.047). In the multivariable logistic regression model, after adjusting for confounding factors, subjects in the last tertile of DII had a nonsignificantly higher HT risk than those in the first tertile (OR = 1.75; 95% CI = 0.83-3.65; P = 0.130). Regarding DTAC, the subjects in the last tertile of DTAC had a significantly decreased risk of HT (OR = 0.47; 95% CI = 0.23-0.98; P = 0.043) compared to those in the first tertile. The DII had a positive correlation with anti-thyroid peroxidase antibody (anti-TPO), thyroglobulin antibodies (TG-Ab) and thyroid-stimulating hormone, while DTAC had a negative correlation with anti-TPO and TG-Ab (P < 0.050).

CONCLUSION

The increase in DII is not associated with an increase in the risk of HT, while DTAC can significantly reduce its risk. Having an anti-inflammatory and antioxidative diet can be effective in improving thyroid function. These conclusions should be confirmed in additional prospective studies.

Petunidin suppresses Hashimoto's thyroiditis by regulating Th1/Th17 homeostasis and oxidative stress

Hashimoto's thyroiditis (HT) is a prevalent autoimmune thyroid disease, necessitating further research to identify effective treatment strategies. Two key pathophysiological factors of HT are inflammation and oxidative stress. Petunidin (PET) is an anthocyanin with anti-inflammatory and antioxidant properties. This study aimed to investigate the effect and mechanism of PET on HT. C57BL/6N mice were injected with thyroglobulin emulsified with adjuvant to establish the HT animal model. Our results showed that PET administration decreased the concentrations of TPOAb, TgAb, T3, T4, IgG, IgA and IgM in HT mice, accompanied by significant alterations in follicle shape and increased lymphocyte infiltrations. Additionally, the apoptosis rate, ROS level, MDA content, CD4+ level, IFN-γ and IL-17A levels, as well as the concentrations of IFN-γ and IL-17, were elevated in HT mice and reduced by PET treatment. Furthermore, HT patients exhibited higher levels of NOX4 and PKM2, which were positively correlated with TPOAb, IFN-γ, and IL-17 concentrations. In HT mice, PET therapy decreased the expression of PKM2 and NOX4 proteins. In summary, PET can improve thyroid dysfunction by suppressing apoptosis, oxidative stress and Th1/Th17 differentiation through regulation of the NOX4/PKM2 axis in HT mice, suggesting its promising potential for HT intervention.

The interlink between thyroid autoimmunity and type 1 diabetes and the impact on male and female fertility

The aim of this review is to discuss the several interconnections between thyroid autoimmunity and type 1 diabetes in terms of epidemiology, immunoserology, genetic predisposition, and pathogenic mechanisms. We will also analyze the impact of these conditions on both male and female fertility. A literature search was carried out using the MEDLINE/PubMed, Scopus, Google Scholar, ResearchGate, and Clinical Trials Registry databases with a combination of keywords. It was found that the prevalence of thyroid autoantibodies in individuals with type 1 diabetes (T1DM) varied in different countries and ethnic groups from 7 to 35% in both sexes. There are several types of autoantibodies responsible for the immunoserological presentation of autoimmune thyroid diseases (AITDs) which can be either stimulating or inhibiting, which results in AITD being in the plus phase (thyrotoxicosis) or the minus phase (hypothyroidism). Different types of immune cells such as T cells, B cells, natural killer (NK) cells, antigen presenting cells (APCs), and other innate immune cells participate in the damage of the beta cells of the islets of Langerhans, which inevitably leads to T1D. Multiple genetic and environmental factors found in variable combinations are involved in the pathogenesis of AITD and T1D. In conclusion, although it is now well-known that both diabetes and thyroid diseases can affect fertility, only a few data are available on possible effects of autoimmune conditions. Recent findings nevertheless point to the importance of screening patients with immunologic infertility for AITDs and T1D, and vice versa.

Assessment of thiol-disulfide and glutathione homeostasis after levothyroxine replacement in individuals with autoimmune or nonautoimmune hypothyroidism

OBJECTIVE

Thyroid hormones are known to affect the biosynthesis and degradation of antioxidant compounds, suggesting a possible link between hypothyroidism and oxidative stress. However, there is no clear consensus in the literature regarding this association. The aim of this study was to evaluate oxidative stress markers (extracellular thiol-disulfide homeostasis and intracellular glutathione homeostasis) in patients with hypothyroidism due to autoimmune (Hashimoto's thyroiditis) or nonautoimmune thyroid disease rendered euthyroid after levothyroxine replacement.

SUBJECTS AND METHODS

The study included 116 patients admitted to the Taksim Training and Research Hospital (Istanbul, Türkiye). Of these, 50 had hypothyroidism due to Hashimoto's thyroiditis (HT group), 30 had nonautoimmune hypothyroidism (NAIH group), and 36 were healthy controls (control group). All participants were women. Extracellular thiol-disulfide homeostasis and intracellular glutathione homeostasis tests were assessed as oxidative stress markers.

RESULTS

Thiol-disulfide homeostasis in both HT and NAIH groups was shifted toward the oxidative spectrum. Compared with the control group, the HT and NAIH groups had lower levels of native (p < 0.001 and p = 0.001, respectively) and total (p = 0.002 and p = 0.012, respectively) thiol, as well as a lower native thiol/total thiol ratio (p < 0.001 for both). The HT group also had higher disulfide levels than the control group (p = 0.027). Reduced glutathione (GSH) and oxidized glutathione (GSSG) values were comparable across all three groups, but the HT and NAIH groups had higher GSSG/GSH (p < 0.001 for both) and GSSG/(GSH+GSSG) ratios (p = 0.003 and p = 0.005, respectively), along with lower GSH/(GSH+GSSG) ratio (p = 0.001 and p = 0.002, respectively) than the control group.

CONCLUSION

Levothyroxine replacement was ineffective in ameliorating oxidative stress in patients with hypothyroidism due to Hashimoto's thyroiditis or nonautoimmune causes, as extracellular thiol-disulfide homeostasis was notably altered in these patients compared with healthy controls. The findings of this study suggest that oxidative stress remains a prevailing issue in patients with autoimmune or nonautoimmune hypothyroidism even after euthyroidism is restored.

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.

Eltroxin and Hesperidin mitigate testicular and renal damage in hypothyroid rats: amelioration of oxidative stress through PPARγ and Nrf2/HO-1 signaling pathway

BACKGROUND

Thyroid hormones (THs) regulate growth, development and function of different tissues. Hypothyroidism is a common clinical disorder characterized by deficiency in THs and adversely affects the development and functions of several organs. This work aimed to investigate the ameliorative effect of eltroxin (ELT), a hypothyroidism medication, and hesperidin (HSP), a flavonoid, against testicular and renal toxicity in hypothyroid rats. Twenty-four rats were divided into four groups and treated orally for 12 weeks. Group I (control), group II (hypothyroidism) received 20 mg/kg carbimazole (CBZ), group III received CBZ and 0.045 mg/kg ELT, and group IV received CBZ and 200 mg/kg HSP.

RESULTS

CBZ administration induced biochemical and histopathological changes in testis and kidney. Co-administration of ELT or HSP significantly (P < 0.05) ameliorated THs, reduced urea and creatinine while raised follicle stimulating hormone (FSH), Luteinizing hormone (LH), and testosterone in serum. Testicular and renal malondialdehyde level as a lipid peroxidation indicator, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were significantly (P < 0.05) decreased while glutathione content, glutathione peroxidase, and glutathione-s-transferase activities were significantly (P < 0.05) increased. The histopathological changes were also diminished. Decreased mRNA and protein expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and peroxisome proliferator-activated receptor gamma(PPARγ) in hypothyroid rats were up-regulated after ELT or HSP treatment.

CONCLUSIONS

ELT and HSP showed antioxidant and anti-inflammatory effects against CBZ-induced testicular and renal toxicity, and these effects may be promoted via activating Nrf2/HO-1 and PPARγ signaling pathways.

The effect of low-level laser therapy on the oxidative stress level and quality of life in patients with Hashimoto's thyroiditis

This study aimed to examine the effects of low-level laser therapy (LLLT) combined with levothyroxine replacement therapy on thyroid function, oxidative stress (OS), and quality of life in patients with Hashimoto's thyroiditis (HT). Forty-six patients diagnosed with HT were randomized to receive active LLLT (n = 23) and sham LLLT (n = 23) twice a week for three weeks. Clinical and laboratory evaluations of the participants were performed before treatment and three months after treatment. Biochemical parameters were taken from the patient file requested by the physician as a routine examination. Malondialdehyde and nitricoxide indicating oxidant stress and superoxide dismutase, catalase, and glutathione, which indicate antioxidant capacity, were used in OS evaluation. The Oxidative Stress Index was calculated by measuring the Total Antioxidant Status and the Total Oxidant Status. At the end of our study, a significant improvement in oxidant and antioxidant biomarker levels showing OS and quality of life was observed in the treatment groups (p < 0.05). There was no change in thyroid function and autoimmunity at the end of the treatment between the two groups (p > 0.05). Improvements in glutathione levels and quality of life were significantly higher in the active treatment group than in the sham-controlled group. LLLT was found to be more effective on OS and quality of life in patients with HT than in patients in the sham-controlled group. It was concluded that LLLT is a safe and effective method that can be used in the treatment of patients with HT.

Adverse effect propensity: A new feature of Gulf War illness predicted by environmental exposures

A third of 1990-1 Gulf-deployed personnel developed drug/chemical-induced multisymptom illness, "Gulf War illness" (GWI). Veterans with GWI (VGWI) report increased drug/exposure adverse effects (AEs). Using previously collected data from a case-control study, we evaluated whether the fraction of exposures that engendered AEs ("AE Propensity") is increased in VGWI (it was); whether AE Propensity is related to self-rated "chemical sensitivity" (it did); and whether specific exposures "predicted" AE Propensity (they did). Pesticides and radiation exposure were significant predictors, with copper significantly "protective"-in the total sample (adjusted for GWI-status) and separately in VGWI and controls, on multivariable regression. Mitochondrial impairment and oxidative stress (OS) underlie AEs from many exposures irrespective of nominal specific mechanism. We hypothesize that mitochondrial toxicity and interrelated OS from pesticides and radiation position people on the steep part of the curve of mitochondrial impairment and OS versus symptom/biological disruption, amplifying impact of new exposures. Copper, meanwhile, is involved in critical OS detoxification processes.

The Influence of Food Regimes on Oxidative Stress: A Permutation-Based Approach Using the NPC Test

(1) Background: This paper aims to assess the existence of significant differences between two dietary regimes (omnivorous vs. semi-vegetarian) with reference to some oxidative stress markers (SOD, GPx, TRxR, GR, AGEs, and AOPPs) using non-parametric combination methodology based on a permutation test. (2) Methods: At the endocrinology unit of Messina University Hospital, two hundred subjects were asked to fill out a questionnaire about their dietary habits. None were under any pharmacological treatment. Using the NPC test, all comparisons were performed stratifying patients according to gender, age (≤40 or >40 years), BMI (normal weight vs. overweight), physical activity (sedentary vs. active lifestyle), TSH, FT4 levels in quartiles, and diagnosis of Hashimoto's thyroiditis. We evaluated differences in oxidative stress parameters in relation to two examined dietary regimes (omnivorous vs. semi-vegetarian). (3) Results: The antioxidant parameters GPx and TRxR were significantly lower in subjects with an omnivorous diet than in semi-vegetarians, particularly in females, both age groups, subjects with normal weight, those not affected by Hashimoto's thyroiditis, and both the sedentary and active lifestyle groups. Finally, the AGE and AOPP markers were significantly lower in semi-vegetarians. (4) Conclusion: Thanks to the NPC methodology, we can state that dietary patterns exert a significant influence on some oxidative stress parameters.

Immunological and Metabolic Causes of Infertility in Polycystic Ovary Syndrome

Infertility has been recognized as a civilizational disease. One of the most common causes of infertility is polycystic ovary syndrome (PCOS). Closely interrelated immunometabolic mechanisms underlie the development of this complex syndrome and lead to infertility. The direct cause of infertility in PCOS is ovulation and implantation disorders caused by low-grade inflammation of ovarian tissue and endometrium which, in turn, result from immune and metabolic system disorders. The systemic immune response, in particular the inflammatory response, in conjunction with metabolic disorders, insulin resistance (IR), hyperadrenalism, insufficient secretion of progesterone, and oxidative stress lead not only to cardiovascular diseases, cancer, autoimmunity, and lipid metabolism disorders but also to infertility. Depending on the genetic and environmental conditions as well as certain cultural factors, some diseases may occur immediately, while others may become apparent years after an infertility diagnosis. Each of them alone can be a significant factor contributing to the development of PCOS and infertility. Further research will allow clinical management protocols to be established for PCOS patients experiencing infertility so that a targeted therapy approach can be applied to the factor underlying and driving the "vicious circle" alongside symptomatic treatment and ovulation stimulation. Hence, therapy of fertility for PCOS should be conducted by interdisciplinary teams of specialists as an in-depth understanding of the molecular relationships and clinical implications between the immunological and metabolic factors that trigger reproductive system disorders is necessary to restore the physiology and homeostasis of the body and, thus, fertility, among PCOS patients.

Associations between empirically derived dietary patterns and oxidative stress and inflammation in adults with primary hypothyroidism: a case-control study

BACKGROUND

Primary hypothyroidism is a common endocrine disorder caused by impaired production of thyroid hormones. Recent studies have shown that dietary habits, oxidative stress, and inflammation may play roles in thyroid hypofunction. Thus, the present article aimed to determine the relationship between major dietary patterns and oxidative stress and inflammation in primary hypothyroid patients and healthy people in Iranian adults.

METHODS

This matched case-control study was conducted on 200 participants (100 cases and 100 controls). The presence of primary hypothyroidism was determined by endocrinologists based on American Thyroid Association (ATA) criteria. Dietary intake was assessed using a validated 168-item, semi-quantitative food frequency questionnaire (FFQ). The principal component analysis (PCA) method was used to derive major dietary patterns. Statistical analysis was performed using logistic regression analysis, and the findings were reported using odds ratios (ORs) with 95% CIs.

RESULTS

We identified 2 major dietary patterns (i.e., healthy and Western dietary patterns). After adjusting for confounding variables, participants in the highest tertile of the healthy eating pattern had lower odds of primary hypothyroidism. Also, there was a significant relationship between total antioxidant capacity (TAC) levels and thyroid hypofunction; however, no significant correlation was seen between the Western dietary pattern and malondialdehyde (MDA) and C-reactive protein (CRP) with hypothyroidism.

CONCLUSIONS

There were statistically direct associations between healthy dietary patterns (loaded with vegetables, nuts and seeds, fruits, dried fruits, olives, garlic, black pepper, starchy vegetables, low-fat dairy, and legumes) and increased TAC levels with a decreased risk of thyroid hypofunction. However, Western dietary patterns and MDA and CRP levels did not associate with an underactive thyroid.

Clinical significance of thyroglobulin antibodies and thyroid peroxidase antibodies in Graves' disease: a cross-sectional study

PURPOSE

The significance of thyroglobulin antibodies (TgAbs) and thyroid peroxidase antibodies (TPOAbs) in Graves' disease (GD) remains unclear. Therefore, this study aimed to clarify the clinical significance of TgAbs and TPOAbs in GD.

METHODS

A total of 442 patients with GD were recruited and divided into four groups based on TgAb and TPOAb positivity. Their clinical parameters and the characteristics of the groups were compared. Cox proportional hazard regression analysis was performed to assess risk factors for GD remission.

RESULTS

The free triiodothyronine (FT3) level was significantly higher in groups positive for TgAbs and TPOAbs than in the other groups. The FT3 to free thyroxine (FT4) (FT3/FT4) ratio was significantly higher and thyrotropin-stimulating hormone (TSH) receptor antibodies (TRAbs) were significantly lower in the TgAb+/TPOAb- group. Time to FT4 recovery was significantly shorter for groups negative for TPOAbs, whereas time to TSH recovery was significantly longer for groups positive for TPOAbs. Cox proportional hazard regression analysis revealed that TgAb positivity, prolonged treatment duration with antithyroid drugs, and Graves' ophthalmopathy treated with methylprednisolone were significantly associated with GD remission and that a smoking history, elevated FT3/FT4 ratio, and treatment with propylthiouracil hindered GD remission.

CONCLUSION

The contributions of TgAbs and TPOAbs to GD pathogenesis differ. Patients positive for TgAbs develop GD with lower TRAb titers and undergo earlier remission than those negative for TgAbs. Patients positive for TPOAbs develop GD with high TRAb titers and need a long time to achieve remission.

The protective role of nutritional antioxidants against oxidative stress in thyroid disorders

An imbalance between pro-oxidative and antioxidative cellular mechanisms is oxidative stress (OxS) which may be systemic or organ-specific. Although OxS is a consequence of normal body and organ physiology, severely impaired oxidative homeostasis results in DNA hydroxylation, protein denaturation, lipid peroxidation, and apoptosis, ultimately compromising cells' function and viability. The thyroid gland is an organ that exhibits both oxidative and antioxidative processes. In terms of OxS severity, the thyroid gland's response could be physiological (i.e. hormone production and secretion) or pathological (i.e. development of diseases, such as goitre, thyroid cancer, or thyroiditis). Protective nutritional antioxidants may benefit defensive antioxidative systems in resolving pro-oxidative dominance and redox imbalance, preventing or delaying chronic thyroid diseases. This review provides information on nutritional antioxidants and their protective roles against impaired redox homeostasis in various thyroid pathologies. We also review novel findings related to the connection between the thyroid gland and gut microbiome and analyze the effects of probiotics with antioxidant properties on thyroid diseases.

Oxidative stress in Hashimoto's thyroiditis: possible adjuvant therapies to attenuate deleterious effects

A number of studies have shown that oxidative stress is related to the pathogenesis of several immunological diseases, such as Hashimoto's thyroiditis (HT), although there is no plausible mechanism to explain it. Thus, we aimed at hypothesizing and providing some possible mechanisms linking oxidative stress to autoimmunity aspects and its implications for HT, as well as adjuvant therapeutic proposals to mitigate the deleterious effects. Our hypothesis is that deficient eating habits, autoimmune regulator gene predisposing gene, dysbiosis and molecular mimicry, unfolded proteins and stress in the endoplasmic reticulum, and thymus involution appear to be the main potential factors leading to HT oxidative stress. Likewise, we show that the use of minerals selenium and zinc, vitamins D and C, as well as probiotics, can be interesting adjuvant therapies for the control of oxidative damage and poor prognosis of HT. Further clinical trials are needed to understand the real beneficial and side effects of these supplements.

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

Background

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

Methods

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

Results

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

Conclusion

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

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

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

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.

Essentiality, relevance, and efficacy of adjuvant/combinational therapy in the management of thyroid dysfunctions

Thyroid dysfunction is the most prevalent endocrine disorder worldwide having an epidemiology of 11% in Indians, 4.6% in the United Kingdom, and 2% in the United States of America among the overall population. The common thyroid disorders include hypothyroidism, hyperthyroidism, Hashimoto's thyroiditis, and thyroid cancer. This review briefly elaborates the molecular regulation and mechanism of thyroid hormone, and its associated thyroid disorders. The thyroid hormones regulate critical biochemical functions in brain development and function. Hypothyroidism is mainly associated with dysregulation of cytokines, increased ROS production, and altered signal transduction in major regions of the brain. In addition, it is associated with reduced antioxidant capacity and increased oxidative stress in humans. Though 70% of thyroid disorders are caused by heredity, environmental factors have a significant influence in developing autoimmune thyroid disorders in people who are predisposed to them. This drives us to understand the relationship between environmental factors and thyroid dysregulated disorders. The treatment option for the thyroid disorder includes antithyroid medications, receiving radioactive iodine therapy, or surgery at a critical stage. However, antithyroid drugs are not typically used long-term in thyroid disease due to the high recurrence rate. Adjuvant treatment of antioxidants can produce better outcomes with anti-thyroid drug treatment. Thus, Adjuvant therapy has been proven as an effective strategy for managing thyroid dysfunction, herbal remedies can be used to treat thyroid dysfunction in the future, which in turn can reduce the prevalence of thyroid disorders.

Serum Levels of Soluble Receptor for Advanced Glycation End Products Are Reduced in Euthyroid Children with Newly Diagnosed Hashimoto's Thyroiditis: A Pilot Study

OBJECTIVE

No data are available on advanced glycation end products (AGEs) and their soluble receptor (sRAGE) in pediatric patients with Hashimoto's thyroiditis (HT). The present study was aimed to simultaneously evaluate serum levels of sRAGE, AGEs, and advanced oxidation protein products (AOPPs) and investigate the relationships between these oxidative stress markers and clinical and biochemical parameters of thyroid function in euthyroid children with HT.

DESIGN

This is a case-control study carried out in a single university hospital center.

METHODS

We enrolled 19 newly diagnosed euthyroid HT pediatric patients (3 M, 16 F; median age 12.44 years, range 6.54-15.81 years) and 16 age-, sex-, and BMI-matched healthy controls (5 M, 11 F; median age 12.83 years, range 5.68-15.07 years). None was on levothyroxine treatment. The exclusion criteria were autoimmune, inflammatory, and infection comorbidities. Patients did not differ significantly from controls with regard to lipid or for anthropometric parameters.

RESULTS

sRAGE levels were significantly lower in HT patients (median 414.30 pg/mL, range 307.30-850.30 pg/mL) than in controls (561.30, 273.20-1121.60 pg/mL; p = 0.034). No differences emerged between patients and controls with regard to serum AGEs (124.25 AU/g prot, 71.98-186.72 vs. 133.90, 94.06-200.78 AU/g prot, p = 0.707) and AOPPs (1.13 nmol/mL, 0.62-1.83 vs. 1.17, 0.76-1.42 nmol/mL, p = 0.545).

CONCLUSIONS

sRAGE levels were decreased in euthyroid children/adolescents at the onset of HT, suggesting that autoimmunity per se seems to play an important role in such a reduction of sRAGE, irrespective of any functional alteration. Children and adolescents suffering from HT may exhibit increased susceptibility to oxidative damage, even when in euthyroid status.

Effect of hypothyroidism and thyroid autoimmunity on the ovarian reserve: A systematic review and meta-analysis

Background

Evidence suggests that hypothyroidism and thyroid autoimmunity (TAI) are possibly associated with ovarian dysfunction. This meta‐analysis aimed to investigate whether hypothyroidism and/or TAI affect the ovarian reserve and evaluated using the anti‐Mullerian hormone (AMH).

Methods

PubMed, EMBASE, Web of Science, and Cochrane Controlled Trials Register databases from inception to October 2020 were searched to identify relevant studies. Studies comparing the AMH levels between the control and the affected groups were included in the data synthesis. The primary endpoint in the meta‐analysis was AMH levels compared with the controls.

Main findings

Nine trials were included in the analysis. The AMH levels were significantly lower in the adults with euthyroid TAI (mean difference −0.12, [95% CI: −0.18 to −0.06]). The AMH levels tended to be lower in subclinical hypothyroidism and overt hypothyroidism than in the control group, although the differences were not significant. The AMH levels were significantly higher in the euthyroid TAI group in the adolescents (mean difference 2.51, [95% CI 1.82 to 3.21]).

Conclusion

TAI and hypothyroidism may affect the ovarian reserve. The opposite effects on AMH levels depending on age suggest that TAI may be implicated in the depletion of follicles in adults following extensive activation of primordial follicles in adolescence.

The Relationship of Thyroid Functions With ADMA, IMA, and Metabolic Laboratory Parameters in Euthyroid Adults With and Without Autoimmune Thyroiditis

OBJECTIVE

To investigate the relationship between thyroid functions and asymmetric dimethylarginine (ADMA), ischemia-modified albumin (IMA), and other metabolic laboratory markers in euthyroid adults and whether narrower thyroidal targets are required for lower metabolic risk.

MATERIALS AND METHODS

Thyroid functions, antithyroid autoantibodies, and metabolic parameters were measured for 115 patients. Forty-seven had autoimmune thyroiditis (AIT). Analyses were performed according to cutoff values of 1, 2, 2.5, and 3 mIU/L for thyrotropin, 0.84 ng/dL for free thyroxine (fT4), and 3.59 ng/dL for free tri-iodothyronine (fT3).

RESULTS

There was no relationship between thyrotropin and fT3 cutoff values and metabolic parameters. Only C-reactive protein was lower in the group with thyrotropin ≤2.5 μIU/L. A weak positive correlation was found between fT4 with IMA and IMA corrected for albumin (r = 0.187, P = .05; r = 0.204, P = .034, respectively). There was no difference between AIT and the metabolic laboratory parameters examined in the study.

CONCLUSION

This study is the first to evaluate ADMA in AIT. Narrower thyroid function targets are not required for better metabolic control in euthyroid adults.

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.

The Level of Zinc, Copper and Antioxidant Status in the Blood Serum of Women with Hashimoto's Thyroiditis

The aim of this study was to analyze selected indicators of oxidative stress. The study subjects consisted of 42 women with Hashimoto’s disease and a control group of 30 healthy women. The concentration of zinc (Zn) and copper (Cu) in the serum was determined by Atomic Absorption Spectrometry (AAS) and the total antioxidative potential by the Ferric Reducing Ability of Plasma (FRAP) method. In addition, an assessment of concentrations of thiobarbituric acid reactive substances (TBARS) and total phenolics was carried out. Our research showed a significant difference in TBARS concentration (p < 0.0001 (ES: 0.92)) without significant differences in Zn, Cu, FRAP and total phenolics concentrations. Analysis of the correlation of the obtained results of biochemical tests for both groups showed a highly significant dependence of FRAP and total phenolics concentration in the blood of the examined women (r = 0.5283, p = 0.0003). The obtained results indicate no differences in Cu, Zn, and FRAP concentrations in the blood between two analyzed groups and a significantly higher concentration of TBARS in Hashimoto’s thyroiditis women. The concentration of total phenolics significantly influences the value of the FRAP.

Influence of Dietary Habits on Oxidative Stress Markers in Hashimoto's Thyroiditis

Background: There is a growing awareness that nutritional habits may influence risk of several inflammatory and immune-mediated disorders, including autoimmune diseases, through various mechanisms. The aim of the present study was to investigate dietary habits and their relationship with redox homeostasis in the setting of thyroid autoimmunity. Materials and Methods: Two hundred subjects (173 females and 27 males; median age, 37 years) were enrolled. None were under any pharmacological treatment. Exclusion criteria were any infectious/inflammatory/autoimmune comorbidity, kidney failure, diabetes, and cancer. In each subject, serum thyrotropin (TSH), free thyroxine, antithyroid antibodies, and circulating oxidative stress markers were measured. A questionnaire on dietary habits, evaluating the intake frequencies of food groups and adherence to the Mediterranean diet, was submitted to each participant. Results: Among the 200 recruited subjects, 81 (71 females and 10 males) were diagnosed with euthyroid Hashimoto's thyroiditis (HT); the remaining 119 (102 females and 17 males) served as controls. In questionnaires, HT subjects reported higher intake frequencies of animal foods (meat, p = 0.0001; fish, p = 0.0001; dairy products, p = 0.004) compared with controls, who reported higher intake frequencies of plant foods (legumes, p = 0.001; fruits and vegetables, p = 0.030; nuts, p = 0.0005). The number of subjects who preferentially consumed poultry instead of red/processed meat was lower in HT subjects than in controls (p = 0.0141). In logistic regression analysis, meat consumption was associated with increased odds ratio of developing thyroid autoimmunity, while the Mediterranean diet traits were protective. In HT subjects, serum advanced glycation end products (markers of oxidative stress) were significantly higher (p = 0.0001) than in controls, while the activity of glutathione peroxidase and thioredoxin reductase, as well as total plasma antioxidant activity, were lower (p = 0.020, p = 0.023, and p = 0.002, respectively), indicating a condition of oxidative stress. Stepwise regression models demonstrated a significant dependence of oxidative stress parameters on consumption of animal foods, mainly meat. Conclusions: The present study suggests a protective effect of low intake of animal foods toward thyroid autoimmunity and a positive influence of such nutritional patterns on redox balance and potentially on oxidative stress-related disorders.

Minerals: An Untapped Remedy for Autoimmune Hypothyroidism?

For decades, the focus of managing autoimmune hypothyroidism has been on thyroxine replacement. Correcting lab parameters such as thyroid stimulating hormone (TSH) has been a primary goal. The increasing prevalence of Hashimoto’s thyroiditis (HT) continues to impact the quality of life in patients. We believe a holistic approach to this disease entity, considering its underlying complex etiopathogenesis, would benefit patients. Nutraceuticals are combinations of essential nutrients and are becoming a part of novel medical treatments despite the lack of regulation. This review aims to present a concise summary of recent developments regarding minerals such as zinc, selenium, magnesium, iron, and their potential clinical benefit as nutraceuticals in patients with HT. We have explored the potential benefits and associations of these minerals in HT and thyroid function. We reviewed relevant articles, metanalyses, and clinical trials in literature platforms such as PubMed, PubMed Central, and Google Scholar. Significant data found in the literature suggesting a potential health benefit of these minerals in HT though there were many studies to the contrary. Many trials demonstrated the restoration of residual symptoms, reversal of HT-associated thyroid morphological changes, and improvement in thyroid functions. Many of these trials lack statistical power due to the small sample sizes, and their external validity may be questionable due to unaccounted confounding factors. In our opinion, to support an evidence-based holistic clinical approach, further scientific evidence is needed. The association of these elements in thyroid function necessitates more large scale pragmatic trials to elucidate the benefits of nutraceuticals in HT.

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.

Serum levels of advanced glycation end products (AGEs) are increased and their soluble receptor (sRAGE) reduced in Hashimoto's thyroiditis

PURPOSE

Advanced glycation end products (AGEs) are increased in conditions of oxidative stress and promote inflammation by interacting with their receptor RAGE on cell membrane. By contrast, the soluble receptor sRAGE exerts protective effects by competing with RAGE for ligand binding. AGEs/sRAGEs interaction is involved in the pathogenesis of several diseases related to oxidative stress. In the present study, we evaluated the AGEs/sRAGEs oxidative balance in Hashimoto' thyroiditis (HT).

METHODS

We measured the levels of sRAGE, by ELISA, and AGEs, by spectrophotometric method, in the serum of 50 HT patients (5 M, 45 F; mean age 38.5 ± 12 years) and 50 age-, sex- and BMI-matched healthy controls. All subjects were euthyroid at recruitment and none was on LT-4 therapy.

RESULTS

Serum sRAGEs were significantly lower (median 424 vs 738 pg/ml; p = 0.001) and AGEs higher (205 vs 114 AU/g prot; p = 0.001) in HT patients compared to controls, and the two parameters were inversely correlated (p = 0.016). Accordingly, the AGEs/sRAGEs ratio was threefold higher in HT patients than controls (0.48 vs 0.15; p = 0.0001). In regression analysis models, serum TPO-Ab were the main predictors for AGEs and sRAGEs levels and AGEs/sRAGEs ratio (p < 0.0001), irrespective of TSH and/or FT4 values.

CONCLUSION

sRAGEs were decreased and AGEs increased, suggesting a dysregulation of AGE/sRAGEs-related oxidative homeostasis in HT patients, even when in euthyroid status. Autoimmunity per se seems to play an important role in AGEs/sRAGE imbalance, irrespective of thyroid function alterations.

gp91phox, a Novel Biomarker Evaluating Oxidative Stress, Is Elevated in Subclinical Hypothyroidism

BACKGROUND

gp91phox, the catalytic core of NADPH oxidase (NOX) and biomarker of NOX activation, has been recently recognized as a parameter of systemic oxidative stress in several studies. Subclinical hypothyroidism (SH) is characteristic of elevated level of serum thyroid stimulating hormone (TSH) and is frequently accompanied with cholesterolemia. In this study, the levels of serum soluble gp91phox were measured to assess the oxidative stress in patients with SH. And the relationship among gp91phox, low-density lipoprotein-C (LDL-C), and TSH was also investigated.

METHODS

A total of 51 subjects were enrolled and categorized into four groups: the healthy controls subjects (n = 13), controls with high level of LDL-C alone (n = 12), SH with normal level of LDL-C (n = 11), and SH with high level of LDL-C (n = 15). The related clinical and laboratory data were collected for statistical analysis. All the patients were newly diagnosed and did not take any medication. The information of lipid profile and thyroid function was extracted, and the concentrations of gp91phox were obtained with ELISA.

RESULTS

The levels of serum soluble gp91phox evidently increased in the patients with SH with a high level of LDL-C (81.52 ± 37.00 ug/mL) as compared to the healthy controls (54.98 ± 1.83ug/mL, p < 0.001), controls with high level of LDL-C (61.21 ± 4.48 ug/mL, p=0.038) and SH with a normal level of LDL-C (62.82 ± 11.67ug/mL, p=0.027). Additionally, the levels of gp91phox showed a significant positive correlation with both the levels of LDL-C (r = 0.595, p < 0.001) and TSH (r = 0.346, p=0.013) by the Spearman correlation analyses. The correlation remained significant even when the effect of another factor was controlled (TSH: when the effect of LDL-C was controlled, r = 0.453, p=0.001; LDL-C: when the effect of TSH was controlled, r = 0.291, p=0.040). The main effect analysis showed an independent main effect of either LDL-C (p = 0.041) or TSH (p=0.022) on gp91phox without interaction (p=0.299).

CONCLUSIONS

Our work demonstrated that the levels of gp91phox, a novel biomarker for measuring the oxidative stress, were significantly elevated in the patients with SH. And LDL-C and TSH were both independent predictors of gp91phox. Abbreviations. BMI : Body mass index; TC : Total cholesterol; LDL-C : Low-density lipoprotein cholesterol; HDL-C : High-density lipoprotein cholesterol; TG : Triglyceride; FBG : Fasting blood glucose; FT3 : Free triiodothyronine; FT4 : Free thyroxine; TSH: Thyroid stimulating hormone; SBP : Systolic blood pressure; DBP : Diastolic blood pressure; SD : Standard deviation; LSD: Least significant difference.

Selenium involvement in mitochondrial function in thyroid disorders

Selenium (Se), an important oligoelement, is a component of the antioxidant system. Over the last decade, it has been ever more frequently discussed in the context of thyroid disorders. Graves' disease and Hashimoto's thyroiditis, differentiated thyroid cancer, and even endemic goiter may have common triggers that are activated by excess reactive oxygen species (ROS), which are involved in various stages of the pathogenesis of thyroid disorders. Most oxidative events occur in mitochondria, organelles that contain enzymes with Se as a cofactor. Mitochondria are responsible for the production of ATP in the cell and are also a major site of ROS production. Thyroid hormone status (the thyroid being the organ with the highest concentration of Se in the body) has a profound impact on mitochondria biogenesis. In this review, we focus on the role of Se in mitochondrial function in thyroid disorders with impaired oxidative stress, since both thyroid hormone synthesis and thyroid dysfunction involve ROS. The role of Se deficiency or its excess in relation to mitochondrial dysfunction in the context of thyroid disorders is therefore of interest.

Thiol/disulfide homeostasis and ischemia modified albumin levels in autoimmune gastritis and their relations with gastric emptying

Background/aim

Autoimmune gastritis is an autoimmune and inflammatory disorder. The aim of this study is to examine dynamic thiol/disulfide homeostasis and ischemia modified albumin levels, and to analyze the association between thiol/disulfide homeostasis and gastric emptying time in autoimmune gastritis.

Materials and methods

Thiol/disulfide homeostasis tests and ischemia modified albumin levels were determined in 50 autoimmune gastritis patients and 53 healthy subjects. Patients with delayed and normal gastric emptying were compared by thiol/disulfide homeostasis tests.

Results

The results showed that native thiol (μmol/L), total thiol (μmol/L), and native thiol/total thiol ratio (%) of the patients with autoimmune gastritis decreased compared to the control group (177.7 ± 34.18 vs. 245.25 ± 33.83, P = 0.001, 227.25 ± 36.78 vs. 284.20 ± 27.19, P = 0.03, and 8.84 ± 1.1 vs. 7.74% ± 1.3%, P = 0.001). In addition, native thiol (μmol/L), total thiol (μmol/L), and native thiol/ total thiol ratio (%) were found to be lower in patients with delayed gastric emptying (198.65 ± 24.27 vs. 167.12 ± 20.51, 241.81 ± 27.14 vs. 213.92 ± 26.35, 8.34 ± 1.29 vs. 7.20 ± 1.83, P = 0.001). Disulfide level, disulfide/native thiol, disulfide/total thiol (P = 0.001) ratios, and ischemia modified albumin levels (ABSU, 0.71 ± 0.08 vs. 0.83 ± 0.07) were found to be higher in autoimmune gastritis patients with delayed gastric emptying (P = 0.001).

Conclusion

The results showed that thiol/disulfide homeostasis in patients with autoimmune gastritis caused an increase in ischemia modified albumin and disulfide whereas a decrease in thiols. An altered thiol/disulfide balance was also observed in patients with delayed gastric emptying. These results suggest that the oxidative process is involved in patients with autoimmune gastritis.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Oxidative stress markers, trace elements, and endocrine disrupting chemicals in children with Hashimoto's thyroiditis

In this study, we aimed to investigate whether bisphenol A (BPA) and di-(2-ethylhexyl) phthalate (DEHP) exposure have any association with Hashimoto's thyroiditis (HT) and its biomarkers and to determine whether oxidative stress biomarkers and trace element levels showed any alterations in children with HT. We found that superoxide dismutase and glutathione peroxidase activities are lower in HT group from control (24% and 46%, respectively, p < 0.05). Zinc levels were significantly lower in HT group vs. control. In addition, the levels of mono-(2-ethylhexyl) phthalate (MEHP) which is the primary metabolite for DEHP, were markedly higher in HT group compared to control (p < 0.05). A negative correlation was observed between urinary BPA levels and fT4. In children with HT, oxidant/antioxidant balance is changed and these differences may be related by EDC exposure, the importance of which should be elucidated with further studies.

Interdependence of oxidative/antioxidant system indicators and thyroid status under conditions of prolonged exposure to small doses of radiation

We have studied the interdependence of the intensity of oxidative processes/antioxidant level and the thyroid status parameters in a group of students aged 18–24 who lived for a long time in the territory of enhanced radioecological control (density of soil contamination by isotopes (137Cs 3.7 ∙ 104 – 18.5 ∙ 104 Bq/m2). We examined 50 people from relatively environmentally friendly areas (control group) and 50 people from IV radiation zone (experimental group). In the experimental group, there were no individuals with clinical manifestations of thyroid pathology. However, subgroups with signs of hyperthyroidism and hypothyroidism were identified. We evaluated the level of cortisol, thyrotrophic hormone (TSH), triiodothyronine (T3), thyroxine (T4), malonic dialdehyde (MDA), ceruloplasmin (CP), transferrin (Tf), sulfhydryl groups (SH); we calculated the oxidative stress index (OSI). The research was conducted one month before the examination time and also during the exams as a factor in increased emotional stress. A lowered CP level was found in the subgroup with signs of hypothyroidism; SH groups – in all subgroups, separated by thyroid status. The oxidative stress index was higher in all students examined of the experimental group, compared with the control. The growth of MDA level is marked in the experimental group – it is the most strongly pronounced in conditions of additional emotional load in people with signs of hyperthyroidism and hypothyroidism. CP level significantly decreased in the subgroup of hyperthyroidism on the background of T3 decrease. OSI increased in all students examined from the experimental group. In the subgroup of hypothyroidism it became significantly higher than in the subgroup of euthyroidism. A positive correlation between the levels of CP and T3 was found. The highest values of the correlation coefficients were noted for subgroups with signs of hyperthyroidism and hypothyroidism, with the coefficient significance increasing under conditions of emotional stress. The index of oxidative stress in the experimental group positively correlated with the level of TSH – in terms of emotional stress, the statistical significance of the coefficients disappeared. In the subgroups divided by thyroid status, variability of interactions between OSI and T3 was observed but it was not statistically significant. It was found that the participation of thyroid status in supporting redox homeostasis in people aged 18–24 who suffered from chronic small-doze radiation exposure was realized mainly by the influence on the antioxidant system. The ability of thyroid hormones to maintain a proper antioxidant state was suppressed in this group. The unbalanced relationship between thyroid hormones and oxidative stress indicators is strongly manifested under conditions of additional emotional stress.

Increased serum interleukin-37 (IL-37) levels correlate with oxidative stress parameters in Hashimoto's thyroiditis

PURPOSE

Interleukin-37 (IL-37), member of the IL-1 family, is a natural suppressor of immune and inflammatory responses. Increased serum IL-37 levels were observed in several autoimmune diseases, including Graves' disease. To our knowledge, no data on Hashimoto's thyroiditis (HT) are available in the literature.

METHODS

Aim of our study was to measure serum IL-37 levels and evaluate their relationship, if any, with oxidative stress markers in HT patients. We enrolled 45 euthyroid HT patients (5 M e 40 F, median age 40 years) and 50 age- and sex-matched healthy controls. None was under L-thyroxine therapy. Serum IL-37 levels were measured by ELISA. Specific serum tests, such as derived reactive oxygen metabolites (d-ROMs), and biological anti-oxidant potential (BAP) test were performed in all subjects to investigate the changes in oxidative balance, and advanced glycation end products (AGEs) were determined as a specific marker of oxidative stress.

RESULTS

IL-37 levels were significantly higher in HT than in controls (median 475 vs. 268 pg/ml, P = 0.018). In the same patients, serum oxidants (d-ROMs) were increased and anti-oxidants (BAP) decreased compared with controls (P = 0.011 and < 0.0001, respectively), clearly indicating an enhanced oxidative stress. In addition, AGEs levels were higher in HT patients than in controls (210 vs. 140 AU/g prot, P < 0.0001) and directly correlated with IL-37 levels (P = 0.048). At multivariate analysis, the main independent predictors that influenced IL-37 levels were both anti-thyroid antibodies (P = 0.026) and AGEs levels (P = 0.001).

CONCLUSIONS

IL-37 is up-regulated in HT and may exert a protective role by counteracting oxidative stress and inflammation.

The protective effect of myo-inositol on human thyrocytes

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

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 effect of obesity and dietary habits on oxidative stress in Hashimoto’s thyroiditis

OBJECTIVE

Increased oxidative stress has been described in patients with Hashimoto’s thyroiditis (HT). The aim of the present study was to investigate whether high oxidative stress is further influenced by obesity and dietary habits in euthyroid women with HT.

METHODS

Two hundred eighteen consecutive euthyroid women with HT were studied and separated in two groups; 102 with thyroxine replacement and 114 without. For the evaluation of oxidative stress, total lipid peroxide levels in serum (TOS) were measured and recoded as ‘high TOS’ vs ‘medium/low TOS’. The type of food and consumption frequency were recorded. Two binary variables were considered; normal vs low fruit consumption and daily vs sporadic vegetable consumption.

RESULTS

‘High TOS’ was more frequent in women under thyroxine replacement (31.4% vs 14.7%, OR = 2.7, 95% CI: 1.4–5.2). The prevalence of ‘high TOS’ was higher among overweight/obese women compared to women with normal BMI (30.4% vs 12.5%, OR = 3.1, 95% CI: 1.5–6.4). Low fruit consumption was associated with increased ‘high TOS’ prevalence (30.6% vs 12.9%, OR = 3.0, 95% CI: 1.4–6.2). Sporadic vegetable consumption was associated with increased ‘high TOS’ prevalence compared to daily consumption (29.9% vs 13.5%, OR = 2.7, 95% CI: 1.3–5.7). The examined risk factors were independent and additive in their effect on TOS. At least three risk factors had to be concomitantly present for the likelihood of ‘high TOS’ to be significantly elevated.

CONCLUSIONS

Oxidative stress is increased in women with HT under thyroxine replacement. Nevertheless, normal BMI, daily fruit and vegetable consumption, all contribute in maintaining oxidative stress at low levels.

Alteration in Prooxidant-antioxidant Balance Associated with Selenium Concentration in Patients with Congenital Hypothyroidism

BACKGROUND

There is a paucity of studies regarding oxidative balance and selenium (Se) status in congenital hypothyroidism. Recently, more attention has been given to the use of Se supplementation as a new treatment for thyroid disorders. Oxidative stress increases in different thyroid disorders and causes many pathological outcomes. The present study aimed to determine the serum prooxidant-anti - oxidant balance (PAB), Se, thyroid stimulating hormone (TSH) and free thyroxine (FT4) concentration in congenital hypothyroidism (CH) patients and the association of their probable change with hematological indices.

METHODS

Blood samples were collected from 60 healthy and 39 CH subjects. Serum PAB values were measured and Se, TSH, FT4 and hematological indices were determined. Data were analyzed by SPSS version 16 and p value less than 0.05 was considered statistically significant.

RESULTS

Serum TSH concentration was significantly higher in CH patients group compared to the controls (p value < 0.05); however, FT4 was in the same concentration in patients and controls. Platelet (Plt) and lymphocytes (Lym) counts markedly decreased in all patients and showed a significant direct correlation with serum TSH levels (rs = 0.307, p value = 0.004 and rs = 0.413, p value < 0.0001). Serum PAB and Se had no significant correlation with he - mato logical indices in the studied subjects.

CONCLUSIONS

Although there was no correlation between PAB and also Se with hematologic and biochemical markers in CH patients, changes in these two factors might be considered as a potential risk factor due to the other known effects of high PAB values and low Se concentrations.

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.

RAGE polymorphisms and oxidative stress levels in Hashimoto's thyroiditis

BACKGROUND

Polymorphisms of the receptor for advanced glycation end products (RAGE) gene have been studied in various autoimmune disorders, but not in Hashimoto's thyroiditis. Also, increased oxidative stress has been described in patients with Hashimoto's thyroiditis. The aim of this study was to investigate the possible role of two common RAGE polymorphisms (-429T>C, -374T>A) in Hashimoto's thyroiditis; in parallel, we studied oxidative stress levels.

MATERIALS AND METHODS

A total of 300 consecutive euthyroid women were examined and classified into three groups: Hashimoto's thyroiditis with treatment (n = 96), Hashimoto's thyroiditis without treatment (n = 109) and controls (n = 95). For a rough evaluation of oxidative stress, total lipid peroxide levels in serum were measured. The -429T>C AluI and -374T>A MfeI polymorphisms of RAGE were studied in genomic DNA.

RESULTS

Significant association of the RAGE system with Hashimoto's thyroiditis was found only with regard to the prevalence of the -429T>C, but not with -374T>A polymorphism. The levels of oxidative stress were significantly elevated in Hashimoto's thyroiditis patients under treatment. Further analysis demonstrated that an oxidative stress cut-off value of 590 μmol/L is associated with an increased risk of progression of Hashimoto's thyroiditis from euthyroidism to hypothyroidism; this risk is further increased in carriers of the RAGE -429T>C polymorphism.

CONCLUSIONS

Our findings indicate that both examined risk factors may be implicated in the occurrence of Hashimoto's thyroiditis, but this covers only a fraction of the pathophysiology of the disease.

A meta-analysis of the association of serum ischaemia-modified albumin levels with human hypothyroidism and hyperthyroidism

Serum levels of ischaemia-modified albumin (IMA) have been studied as a novel and simple measure of oxidative stress (OXS) in different thyroid pathologies. However, results of available studies in the literature were not consistent. This meta-analysis was attempted to quantify the overall effect size for serum IMA levels in human hypothyroidism (HT) and hyperthyroidism (HYT) and to study its associations with the thyroid profile. Databases of PubMed/Medline, EMBASE, Google Scholar, Web of Science and Science Direct were searched for articles. Data on serum IMA levels in HT, HYT patients and euthyroid controls were extracted to compute standardized mean differences (SMD) by the random-effects model. The associations between IMA and thyroid profile were computed by the meta-analysis of correlation coefficients. IMA levels in HT patients (SMD=1.12; Z=2.76; P=0.006) and HYT patients (SMD=1.64; Z=2.57; P=0.01) were significantly higher than in euthyroid controls and the thyroid treatment showed a favourble effect on serum IMA levels. There were strong and significant correlations between IMA and hormonal status in HT and HYT groups. This meta-analysis showing increased IMA level in both HT and HYT patients and its association with thyroid profile suggests that serum IMA could be used as a simple measure of increased OXS in thyroid dysfunction.

Dynamic thiol/disulfide homeostasis in patients with autoimmune subclinical hypothyroidism

OBJECTIVE

The aim of this study was to investigate dynamic thiol/disulfide homeostasis in autoimmune subclinical hypothyroidism.

METHODS

Forty-eight patients with a new diagnosis of subclinical hypothyroidism due to Hashimoto thyroiditis who were not yet under medical therapy, and 48 healthy control subjects were enrolled. Thiol/disulfide homeostasis [native thiol-disulfide exchanges] was measured in both groups using the automated method developed by Erel and Neselioglu. An absolute difference of 0.5 between the total thiol and native thiol concentrations revealed the disulfide bond amount.

RESULTS

The native thiol level (p = 0.014) and native thiol/total thiol ratio (p = 0.001) were lower in patients with subclinical hypothyroidism than in the control group. Meanwhile, the disulfide level (p = 0.004), disulfide/native thiol ratio (p = 0.001), and disulfide/total thiol (p = 0.001) ratio were higher in patients with subclinical hypothyroidism than in the control group. The antithyroid peroxidase and anti-thyroglobulin levels were positively correlated with the disulfide/native thiol ratio (r = 0.339, p = 0.019; r = 0.243, p = 0.023, respectively) and the disulfide/total thiol ratio (r = 0.133, p = 0.019; r = 0.238, p = 0.026, respectively) and negatively correlated with the native thiol/total thiol ratio (r = -0.292, p = 0.004; r = -0.233, p = 0.022, respectively).

CONCLUSION

We found that thiol/disulfide homeostasis shifted to disulfide formation in patients with subclinical hypothyroidism and that thyroid autoantibodies were positively correlated with thiol oxidation. It is not clear whether abnormal thiol/disulfide homeostasis is a cause or a consequence in Hashimoto thyroiditis. Further studies are required.

Evaluation of Serum S100A8/S100A9 Levels in Patients with Autoimmune Thyroid Diseases

BACKGROUND

The correlation of S100A8/S100A9 with various inflammatory conditions, including autoimmune diseases have been reported. There is no study investigating the levels of S100A8/S100A9 in autoimmune thyroid diseases (AITD).

AIMS

We aimed to evaluate the level of serum S100A8/S100A9 in AITD.

STUDY DESIGN

Case control study.

METHODS

Fifty patients with AITD (25 Hashimoto's thyroiditis (HT) and 25 Graves' disease (GD)) were included in the study. Twenty seven healthy subjects participated as a control group. Blood samples were obtained in the 3 months after the initiation of medical treatment. Serum levels of total antioxidant status (TAS), total oxidative status (TOS), total free sulfhydryl (SH), lipid hydroperoxide (LOOH) and S100A8/S100A9 were analyzed.

RESULTS

The patients with AITD had significantly higher S100A8/S100A9, OSI, LOOH and TOS levels than the healthy control group. There was no significant difference between GD and HT patients in terms of S100A8/S100A9, TOS and OSI levels. S100A8/S100A9 level was positively correlated with LOOH, TOS and OSI levels but negatively correlated with -SH level in the patients with AITD.

CONCLUSION

Serum S100A8/S100A9 levels were increased in patients with AITD and positively correlated with LOOH, TOS and OSI whereas negatively correlated with SH.

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.

Oxidative Stress and Advanced Glycation End Products in Hashimoto's Thyroiditis

BACKGROUND

Oxidative stress, which occurs as a result of an imbalance between free-radical production and antioxidant defense mechanisms, has been implicated in the pathogenesis of several autoimmune disorders, including thyroid diseases. Importantly, it has been correlated to thyroid dysfunction. This study investigated the changes in oxidative balance in euthyroid Hashimoto's thyroiditis (HT) by means of specific serum tests, such as derived reactive oxygen metabolites (d-ROMs) and the biological antioxidant potential (BAP) test. In addition, advanced glycation end products (AGEs) and advanced oxidation protein products (AOPPs)--compounds formed by the transformation of proteins--were evaluated as potential new markers of oxidative stress in this disease.

METHODS

This study included 134 euthyroid subject: 71 newly diagnosed HT patients (63 females; M age = 38 ± 13 years) and 63 age and sex-matched healthy controls. None of them were on thyroxine therapy.

RESULTS

Serum d-ROMs were elevated, and BAP decreased in HT patients compared with controls (p < 0.001), and the two parameters were inversely correlated (r = -0.211; p = 0.027), clearly indicating an enhanced oxidative stress. Furthermore, AGE levels were higher in HT patients (M = 223.18 AU/g prot) than in controls (M = 189.636 AU/g prot; p = 0.020) and inversely correlated with BAP levels (r = -0.196; p = 0.037). In uni- and multivariate analysis, serum antithyroperoxidase antibodies were the main predictors for d-ROMs (p = 0.006), BAP (p < 0.001), and AGEs (p = 0.014), irrespective of thyrotropin and/or free thyroxine values. No differences in AOPPs levels were found between patients and controls (p = 0.923).

CONCLUSIONS

Oxidants are increased and antioxidants decreased in euthyroid HT patients. As a result, the oxidative/antioxidative balance is shifted toward the oxidative side. Moreover, this study reports on a possible significant involvement of AGEs in HT, thus contributing to a better definition of the redox homoeostasis dysregulation in HT.