Proteins oxidation and autoantibodies' reactivity against hydrogen peroxide and malondialdehyde -oxidized thyroid antigens in patients' plasmas with Graves' disease and Hashimoto Thyroiditis

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.

Regulation of the cellular redox state and the expression of DNA methyltransferase-1 in peripheral blood mononuclear cells from patients with Graves' disease

BACKGROUND

Graves' disease is an autoimmune disorder characterised by excessive production of thyroid hormones, which induces increased cellular metabolism in most tissues and increased production of reactive oxygen species (ROS). The aim of this work was to analyse the effect of ROS on cell viability and the expression of catalase (CAT), glutathione peroxidase-1 (GPx-1), superoxide dismutase (SOD-1) and DNA methyltransferase-1 (DNMT-1) in peripheral blood mononuclear cells (PBMC) from patients with newly diagnosed Graves' disease or treated with methimazole.

PATIENTS AND METHODS

For this study, women patients with newly diagnosed Graves' disease (n=18), treated with methimazole (n=6) and healthy subjects (n=15) were recruited. ROS were evaluated by flow cytometry, and the viability/apoptosis of PBMC was analysed by flow cytometry and fluorescence microscopy. Genomic expression of CAT, GPx-1, SOD-1 and DNMT-1 was quantified by real-time PCR.

RESULTS

We found high levels of ROS and increased expression of CAT, GPx-1, SOD-1 and DNMT-1 in PBMC from patients with newly diagnosed Graves' disease. Methimazole treatment reversed these parameters. Cell viability was similar in all study groups.

CONCLUSIONS

ROS induces the expression of CAT, GPx-1, and SOD-1. The activity of these enzymes may contribute to the protection of PBMC from the harmful effect of free radicals on cell viability. Increased expression of DNMT-1 may be associated with aberrant methylation patterns in immunoregulatory genes contributing to autoimmunity in Graves' disease.

Increased Mitochondrial DNA Copy Number and Oxidative Damage in Patients with Hashimoto's Thyroiditis

Background:

The purpose of present study was to investigate mitochondrial DNA copy number (mtDNAcn) and mtDNA damage in peripheral blood of patients with Hashimoto’s thyroiditis (HT) and healthy controls (HC).

Methods:

The relative mtDNAcn and oxidative DNA damage in this case-control study were measured in peripheral blood of 50 patients with Hashimoto’s thyroiditis and 50 healthy controls using quantitative real-time PCR. The study was conducted in Tehran University of Medical Sciences hospital, Tehran, Iran in 2018.

Results:

HT patients had significantly higher mitochondrial DNA copy number and mitochondrial oxidative damage than the comparison group.

Conclusion:

These data suggest the possible involvement of mitochondria and oxidative stress in the pathophysiology of 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.

Oxidative stress enhances the immune response to oxidatively modified catalase enzyme in patients with Graves' disease

BACKGROUND

Oxidative stress is associated with several autoimmune disorders and oxidative modification of proteins that may result in autoimmune response. This study aims to evaluate the catalase (CAT) activity and the autoimmune response against the native CAT and the oxidatively modified enzyme in patients with Graves' disease (GD) and healthy controls in a comparative way.

METHODS

The CAT activity was evaluated via spectrophotometric method. Using enzyme-linked immunosorbent assay, the reactivities of autoantibody toward native, malondialdehyde (MDA) and hydrogen peroxide (H2 O2 ) modified CAT were evaluated in plasmas of patients and controls.

RESULTS

Reduced CAT activity was found in patients compared with controls (P < .05). It was proved that levels of IgG antibodies against MDA-modified CAT were higher than against unmodified ones (P < .001). No changes were found for the reactivities to H2 O2 -modified CAT. Positive correlation was found between the reactivity to MDA-modified CAT and the triiodothyronine level (P < .001, r = .6).

CONCLUSION

Our findings incriminate the MDA in the autoantibodies reactivity to oxidatively modified CAT leading to a disturbed oxidative profile and/or the progression of GD pathology.

Selenium deficiency inhibits micRNA-146a to promote ROS-induced inflammation via regulation of the MAPK pathway in the head kidney of carp

Selenium (Se) is a necessity in multiple species of fish. Se plays an important role in immunoregulation, inflammation, and antioxidant systems in fish and other animals. The head kidney is the major immune organ in adult carp, and it produces white blood cells and destroys old red blood cells. The present study aimed to explore the effects and regulatory molecular mechanisms of Se on ROS and micRNA-146a as part of the inflammatory response in fancy carp. Adult fancy carp were fed different concentrations of Se in their diets. The Se content of the head kidney changed in a pattern consistent with the dietary content of Se. Se deficiency induced a significant increase in ROS, restrained the activities of GPx, SOD and CAT and increased MDA content. qPCR analysis showed a reduction in micRNA-146a with Se deficiency. The Se content, miRNA-146a expression and ROS levels were correlated. H₂O₂ cell stimulation assays found that ROS could activate the MAPK pathway, and ELISA results showed p38, JNK and ERK phosphorylation significantly increased with H₂O₂ stimulation. TNF-α, IL-1β, and IL-6 were appreciably increased. At same time, miRNA-146a, which should have increased to regulate the inflammatory response, was reduced with Se deficiency. Therefore, with Se deficiency, the head kidney was inflamed. All these results indicated that Se deficiency inhibits micRNA-146a to promote ROS-induced inflammation via regulating the MAPK pathway in the head kidney of carp. The present study revealed that supplementing the diet of carp with selenium is beneficial for growth and disease prevention.

Dihydrotestosterone regulates oxidative stress and immunosuppressive cytokines in a female BALB/c mouse model of Graves' disease

Background: Graves' disease (GD) is an autoimmune disease that affects more women than men. In our previous study, a potent bioactive androgen, 5α-dihydrotestosterone (DHT) showed a protective effect against GD in female BALB/c mice. Evidence indicates that abnormal oxidative stress and immunosuppressive cytokines (TGF-β, IL-35) play critical roles in the pathogenesis and development of GD. The purpose of this research is to measure these cytokines and oxidative stress markers to explore potential protective mechanisms of DHT in a BALB/c mouse model of GD. Methods: GD was induced in female BALB/c mice by intramuscular injection of an adenovirus expressing the A-subunit of the TSH receptor (Ad-TSHR289). DHT or a matching placebo was injected every 3 days. Mice were sacrificed four weeks after the third virus immunization to obtain blood, thyroid and spleen for further analysis. Results: Thyroid hormones were significantly reduced in DHT treated GD mice. In addition, DHT attenuated thyroid oxidative injuries in GD mice, as shown by decreased total antioxidation capability (TAOC), superoxide dismutase (SOD) and the level of malondialdehyde (MDA). The levels of immunosuppressive cytokines (TGF-β, IL-35) in DHT group were significant higher compared with the GD group. Conclusions: The results demonstrated that DHT could reduce the severity of GD in female BALB/c mice by regulating oxidative stress. The upregulation of immunosuppressive cytokines might be another important protective mechanism.