Inhibition of 125I organification and thyroid hormone release by interleukin-1, tumor necrosis factor-alpha, and interferon-gamma in human thyrocytes in suspension culture

Prognostic role of euthyroid sick syndrome in MIS-C: results from a single-center observational study

Background

Euthyroid sick syndrome (ESS) is characterized by low serum levels of free triiodothyronine (fT3) with normal or low levels of thyroid stimulating hormone (TSH) and free thyroxine (fT4) and is reported in different acute clinical situations, such as sepsis, diabetic ketoacidosis and after cardiac surgery. Our aim was to evaluate the predicting role of ESS for disease severity in patients with Multisystem Inflammatory Syndrome in children (MIS-C).

Methods

A single-centre observational study on consecutive patients with MIS-C. Before treatment clinical, and laboratory data were collected and, in a subset of patients, thyroid function tests were repeated 4 weeks later. Variables distribution was analyzed by Mann-Whitney U-test and correlations between different parameters were calculated by Spearman's Rho coefficient.

Results

Forty-two patients were included and 36 (85.7%) presented ESS. fT3 values were significantly lower in patients requiring intensive care, a strong direct correlation was shown between fT3 and Hb, platelet count and ejection fraction values. A significant inverse correlation was retrieved between fT3 levels and C-reactive protein, brain natriuretic peptide, IL-2 soluble receptor and S-100 protein. Subjects with severe myocardial depression (EF < 45%) had lower fT3 values than subjects with higher EF. The thyroid function tests spontaneously normalized in all subjects who repeated measurement 4 weeks after admission.

Conclusion

ESS is a frequent and transient condition in acute phase of MIS-C. A severe reduction of fT3 must be considered as important prognostic factor for severe disease course, with subsequent relevant clinical impact in the management of these patients.

Low T3 syndrome is associated with 30-day mortality in adult patients with fulminant myocarditis

Background

Fulminant myocarditis (FM) is a critical disease with high early mortality. Low triiodothyronine syndrome (LT3S) was a strong predictor of poor prognosis of critical diseases. This study investigated whether LT3S was associated with 30-day mortality in FM patients.

Methods

Ninety-six FM patients were divided into LT3S (n=39, 40%) and normal free triiodothyronine (FT3) (n=57, 60%) groups based on serum FT3 level. Univariable and multivariable logistic regression analyses were performed to identify independent predictors of 30-day mortality. Kaplan-Meier curve was used to compare 30-day mortality between two groups. Receiver operating characteristic (ROC) curve and decision curve analysis (DCA) were used to assess the value of FT3 level for 30-day mortality prediction.

Results

Compared to normal FT3 group, LT3S group had higher incidence of ventricular arrhythmias, worse hemodynamics, worse cardiac function, more severe kidney impairment, and higher 30-day mortality (48.7% vs. 12.3%, P<0.001). In univariable analysis, LT3S (odds ratio [OR]:6.786, 95% confidence interval [CI]:2.472-18.629, P<0.001) and serum FT3 (OR:0.272, 95%CI:0.139-0.532, P<0.001) were significant strong predictors of 30-day mortality. After adjustment for confounders in multivariable analysis, LT3S (OR:3.409, 95%CI:1.019-11.413, P=0.047) and serum FT3 (OR:0.408, 95%CI:0.199-0.837, P=0.014) remained independent 30-day mortality predictors. The area under the ROC curve of FT3 level was 0.774 (cut-off: 3.58, sensitivity: 88.46%, specificity: 62.86%). In DCA, FT3 level showed good clinical-application value for 30-day mortality prediction.

Conclusion

In FM patients, LT3S could independently predict 30-day mortality. FT3 level was a strong 30-day mortality predictor and a potentially useful risk-stratification biomarker.

Study of thyroid dysfunction in people living with HIV in Nepalese population undergoing antiretroviral therapy: a cross-sectional study

INTRODUCTION

Thyroid dysfunction is one of the most common endocrine disorders in people living with HIV (PLHIV). The abnormality in thyroid function has been linked with the adverse effects of prolonged antiretroviral therapy (ART) in PLHIV, but its prevalence remains obscure. The present study aimed to determine the prevalence of impaired thyroid function and its relationship to ART duration in Nepalese people living with HIV.

METHODS

This cross-sectional clinical laboratory based study was conducted at SRL Diagnostics Nepal, Pvt. Ltd. from October 2021 to May 2022. Two hundred and three HIV-seropositive patients enrolled at Tribhuvan University Teaching Hospital (TUTH) in Kathmandu, Nepal were examined for their thyroid function test (TFT) by analyzing the serum T3, T4, and TSH concentrations using a fully automated COBAS e411 analyzer (Roche Diagnostics, USA) based on the electrochemiluminescence assay (ECLIA).

RESULTS

Out of 203 PLHIV, 22 (10.83%) had a thyroid disorder, with subclinical hypothyroidism (n = 16, 72.73%) being the most common, followed by subclinical hyperthyroidism (n = 3, 13.63%). Thyroid dysfunction had no significant correlation with HIV/ART duration (p = 0.304) and sex (p = 0.419), whereas, the risk of thyroid dysfunction was induced with the rise in the age of the PLHIV (p = 0.002, ϕ = 0.274). There were no significant differences in the mean serum T3, T4 and TSH values among different sexes and the HIV/ART duration, however a significant difference in the mean values of TSH (F (3, 199) = 3.231, p = 0.023) and T3 (F (3, 199) = 4.587, p = 0.004) among the different age-groups were shown. The mean T3 values also indicated a gradual decrease with increasing age.

CONCLUSION

The study revealed subclinical hypothyroidism as the prevailing thyroid disorder associated with PLHIV. The risk of thyroid dysfunction in PLHIV was neither gender specific nor being attributed by the ART duration in Nepalese population; however, elderly PLHIV were highly susceptible to the risk of thyroid disorder.

Evolution of non-thyroidal illness syndrome in acute decompensation of liver cirrhosis and acute-on-chronic liver failure

BACKGROUND AND AIMS

Non-thyroidal illness syndrome (NTIS) is frequent in critically ill patients and associated with adverse outcomes. We aimed to characterize the evolution of NTIS in patients with acute decompensation (AD) of cirrhosis and acute-on-chronic liver failure (ACLF), since NTIS is not well described in these newly defined syndromes.

METHODS

Thyroid hormones (TH) were quantified at baseline in consecutive patients with cirrhosis. In addition, 76 inflammatory mediators were quantified by proximity extension analysis assay in a subgroup of patients. Associations between TH, cirrhosis stage, mortality and inflammation were assessed.

RESULTS

Overall, 437 patients were included, of whom 165 (37.8%), 211 (48.3%), and 61 (14%) had compensated cirrhosis (CC), AD, and ACLF. FT₃ concentrations were lower in AD versus CC, and further decreased in ACLF. Importantly, NTIS was present in 83 (39.3%) patients with AD and in 44 (72.1%) patients with ACLF (P<0.001). Yet, TSH and TSH-based indexes (TSH/FT₃-ratio, thyroid index) showed an U-shaped evolution during progression of cirrhosis, suggesting a partially preserved responsiveness of the hypothalamus and pituitary in AD. Infections were associated with lower FT₃ concentrations in AD, but not in ACLF. Low FT₃ concentrations correlated significantly with 90-day mortality. Both, AD/ACLF and NTIS, were associated with signatures of inflammatory mediators, which were partially non-overlapping.

CONCLUSION

NTIS is frequent already in AD and therefore precedes critically illness in a subgroup of patients with decompensated cirrhosis. This might constitute a new paradigm of TH signaling in cirrhosis, offering opportunities to explore preventive effects of TH in AD.

Low triiodothyronine syndrome is associated with stroke-associated pneumonia

OBJECTIVE

Stroke-associated pneumonia (SAP) is the most common early consequence in patients suffering from an acute ischaemic stroke (AIS). The purpose of this study was to explore the possible relationship between low triiodothyronine (T3) syndrome and SAP in stroke patients.

METHODS

This study recruited 2460 consecutive AIS patients. SAP was defined according to the modified Centers for Disease Control and Prevention criteria for hospital-acquired pneumonia. The thyroid hormones levels were measured within 24 h after admission. Low T3 syndrome was characterized as T3 below the lower limit of the reference interval accompanied by normal TSH levels.

RESULTS

Among the total patients, 336 (13.7%) patients were diagnosed with SAP. SAP in individuals with low T3 syndrome was substantially greater (p < .001) as compared to those without low T3 syndrome. After adjusting for possible confounders, low T3 syndrome (adjusted odds ratio [aOR] = 1.59; 95% confidence interval [CI], 1.20-2.09; p = .001) remained significant in our logistic model. Patients with low T3 syndrome had a higher risk of severe SAP (aOR = 2.17, 95% confidence interval [CI] 1.38-3.44; p = .001).

CONCLUSION

Low T3 syndrome, independent of recognized risk factors, is a possible risk factor for in-hospital SAP, which can help clinicians in the early detection and treatment of high-risk patients.

Criminal of Adverse Pregnant Outcomes: A Perspective From Thyroid Hormone Disturbance Caused by SARS-CoV-2

Nowadays, emerging evidence has shown adverse pregnancy outcomes, including preterm birth, preeclampsia, cesarean, and perinatal death, occurring in pregnant women after getting infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the underlying mechanisms remain elusive. Thyroid hormone disturbance has been unveiled consistently in various studies. As commonly known, thyroid hormone is vital for promoting pregnancy and optimal fetal growth and development. Even mild thyroid dysfunction can cause adverse pregnancy outcomes. We explored and summarized possible mechanisms of thyroid hormone abnormality in pregnant women after coronavirus disease 2019 (COVID-19) infection and made a scientific thypothesis that adverse pregnancy outcomes can be the result of thyroid hormone disorder during COVID-19. In which case, we accentuate the importance of thyroid hormone surveillance for COVID-19-infected pregnant women.

COVID-19 and thyroid function: What do we know so far?

Coronavirus disease 2019 (COVID-19) was characterized as a pandemic in March, 2020 by the World Health Organization. COVID-19 is a respiratory syndrome that can progress to acute respiratory distress syndrome, multiorgan dysfunction, and eventually death. Despite being considered a respiratory disease, it is known that other organs and systems can be affected in COVID-19, including the thyroid gland. Thyroid gland, as well as hypothalamus and pituitary, which regulate the functioning of most endocrine glands, express angiotensin-converting enzyme 2 (ACE2), the main protein that functions as a receptor to which SARS-CoV-2 binds to enter host cells. In addition, thyroid gland is extremely sensitive to changes in body homeostasis and metabolism. Immune system cells are targets for thyroid hormones and T3 and T4 modulate specific immune responses, including cell-mediated immunity, natural killer cell activity, the antiviral action of interferon (IFN) and proliferation of T- and B-lymphocytes. However, studies show that patients with controlled hypothyroidism and hyperthyroidism do not have a higher prevalence of COVID-19, nor do they have a worse prognosis when infected with the virus. On the other hand, retrospective observational studies, prospective studies, and case reports published in the last two years reported abnormal thyroid function related to acute SARS-CoV-2 infection or even several weeks after its resolution. Indeed, a variety of thyroid disorders have been documented in COVID-19 patients, including non-thyroidal illness syndrome (NTIS), subacute thyroiditis and thyrotoxicosis. In addition, thyroid disease has already been reported as a consequence of the administration of vaccines against SARS-CoV-2. Overall, the data revealed that abnormal thyroid function may occur during and in the convalescence post-COVID condition phase. Although the cellular and molecular mechanisms are not completely understood, the evidence suggests that the "cytokine storm" is an important mediator in this context. Thus, future studies are needed to better investigate the pathophysiology of thyroid dysfunction induced by COVID-19 at both molecular and clinical levels.

The cytokine storm and thyroid hormone changes in COVID-19

BACKGROUND

COVID-19 is now a worldwide pandemic. Among the many extra-pulmonary manifestations of COVID-19, recent evidence suggested a possible occurrence of thyroid dysfunction.

PURPOSE

The Aim of the present review is to summarize available studies regarding thyroid function alterations in patients with COVID-19 and to overview the possible physio-pathological explanations.

CONCLUSIONS

The repercussions of the thyroid of COVID-19 seem to be related, in part, with the occurrence of a "cytokine storm" that would, in turn, induce a "non-thyroidal illness". Some specific cytokines and chemokines appear to have a direct role on the hypothalamus-pituitary-thyroid axis. On the other hand, some authors have observed an increased incidence of a destructive thyroiditis, either subacute or painless, in patients with COVID-19. The hypothesis of a direct infection of the thyroid by SARS-Cov-2 stems from the observation that its receptor, ACE2, is strongly expressed in thyroid tissue. Lastly, it is highly probable that some pharmaceutical agents largely used for the treatment of COVID-19 can act as confounding factors in the laboratory evaluation of thyroid function parameters.

Serum interferon levels associated with the disease activity in women with overt Graves' disease

BACKGROUND

Inflammatory cytokines participate in immune reactions and the pathogenesis of autoimmunity. Herein, we quantified four groups of inflammatory cytokines, including interferons (IFNs), the tumor necrosis factor (TNF) superfamily (TNFSF), interleukin (IL)-related cytokines, and bone and extracellular matrix remodeling-related cytokines to determine their contributions in women with overt Graves' disease (GD).

METHODS

Forty-three women with GD were enrolled in this cross-sectional study. Thirty-seven cytokines, thyroid-stimulating hormone (TSH), free thyroxine, and TSH receptor antibody (TSHRAb) were quantified. GD patients with a low TSH level at the time of sample collection were defined as having active GD.

RESULTS

Patients with active GD had higher IFN-α2, IFN-γ, IFN-λ1, and IFN-λ2 levels than those with inactive GD. In addition, certain TNFSF cytokines, including soluble cluster of differentiation 30 (sCD30), TNFSF member 14 (TNFSF14), pentraxin (PTX)-3, soluble TNF receptor 2 (sTNF-R2), and thymic stromal lymphopoietin (TSLP) were higher in active GD than in inactive GD. Moreover, active GD patients had higher IL-2, IL-12(p40), osteocalcin (OCN), and matrix metalloproteinase (MMP)-3 than inactive GD patients. All IFNs except IFN-λ1 were correlated with TSHRAb titers. Moreover, TNFSF cytokines, consisting of B-cell-activating factor, sCD30, TNFSF14, PTX-3, sTNF-R2, and TSLP, were associated with TSHRAb levels.

CONCLUSIONS

Serum IFNs could be the most remarkable cytokines in modulating the disease severity and TSHRAb titers in women with full-blown GD. Further molecular-based research to clarify the actual role of IFNs in the disease progression of GD is needed.

Sick Euthyroid Syndrome on Presentation of Patients With COVID-19: A Potential Marker for Disease Severity

OBJECTIVE

Precise risk stratification and triage of coronavirus disease 2019 (COVID-19) patients are essential in the setting of an overwhelming pandemic burden. Clinical observation has shown a somewhat high prevalence of sick euthyroid syndrome among patients with COVID-19. This study aimed to evaluate the predictive value of free triiodothyronine (FT3) at the clinical presentation of COVID-19 for disease severity and death.

METHODS

This retrospective cohort study was based on electronic medical records. The study was conducted at Sheba Medical Centre, a tertiary hospital where several acute and chronic wards have been dedicated to the treatment of patients with COVID-19. The primary outcome measure was death during hospitalization; secondary outcomes included hospitalization in intensive care, mechanical ventilation, and length of hospitalization.

RESULTS

Of a total of 577 polymerase chain reaction-positive patients with COVID-19 hospitalized between February 27 and July 30, 2020, 90 had at least 1 measurement of thyroid-stimulating hormone, free thyroxine, and FT3 within 3 days of presentation. After applying strict exclusion criteria, 54 patients were included in the study. Patients in the lowest tertile of FT3 had significantly higher rates of mortality (40%, 5.9%, and 5.9%, P = .008), mechanical ventilation (45%, 29.4%, and 0.0%; P = .007) and intensive care unit admission (55%, 29.4%, and 5.9%, P = .006). In multivariate analyses adjusted for age, Charlson comorbidity index, creatinine, albumin, and white blood cell count. FT3 remained a significant independent predictor of death.

CONCLUSION

FT3 levels can serve as a prognostic tool for disease severity in the early presentation of COVID-19.

Analysis of the Molecular Mechanisms of the Effects of Prunella vulgaris against Subacute Thyroiditis Based on Network Pharmacology

Prunella vulgaris (PV) has a long history of application in traditional Chinese and Western medicine as a remedy for the treatment of subacute thyroiditis (SAT). This study applied network pharmacology to elucidate the mechanism of the effects of PV against SAT. Components of the potential therapeutic targets of PV and SAT-related targets were retrieved from databases. To construct a protein-protein interaction (PPI) network, the intersection of SAT-related targets and PV-related targets was input into the STRING platform. Gene ontology (GO) analysis and KEGG pathway enrichment analysis were carried out using the DAVID database. Networks were constructed by Cytoscape for visualization. The results showed that a total of 11 compounds were identified according to the pharmacokinetic parameters of ADME. A total of 126 PV-related targets and 2207 SAT-related targets were collected, and 83 overlapping targets were subsequently obtained. The results of the KEGG pathway and compound-target-pathway (C-T-P) network analysis suggested that the anti-SAT effect of PV mainly occurs through quercetin, luteolin, kaempferol, and beta-sitosterol and is most closely associated with their regulation of inflammation and apoptosis by targeting the PIK3CG, MAPK1, MAPK14, TNF, and PTGS2 proteins and the PI3K-Akt and TNF signaling pathways. The study demonstrated that quercetin, luteolin, kaempferol, and beta-sitosterol in PV may play a major role in the treatment of SAT, which was associated with the regulation of inflammation and apoptosis, by targeting the PI3K-Akt and TNF signaling pathways.

Simultaneous measurement of twenty-nine circulating cytokines and growth factors in female patients with overt autoimmune thyroid diseases

Cytokines and growth factors participate in immune responses, and the pathogenesis of autoimmune diseases. Herein, we simultaneously examined differential levels of 29 circulating factors to determine their associations in female patients with overt autoimmune thyroid disease (AITD). We enrolled 40 patients with Graves' disease (GD), 20 patients with Hashimoto's thyroiditis (HT), and 14 healthy controls. Twenty-nine circulating factors were simultaneously measured. GD patients with low thyroid-stimulating hormone at the time of sample collection were defined as having active GD. B-cell activating factor (BAFF) levels were associated with GD and HT (p = .001 and .001, respectively) and interferon (IFN)-α levels were higher in the HT group than in the control group (p = .021). Significant associations of serum BAFF and tumour necrosis factor (TNF)-α levels with free thyroxin (FT4) were present in HT (r = -0.498, p = .026, and r = 0.544, p = .013, respectively). Meanwhile, there were significant associations of FT4 with interleukin (IL)-4 and eotaxin levels in GD (r = 0.354, p = .025 and r = 0.384, p = .014, respectively). In active GD, serum BAFF and eotaxin level were correlated with FT4 levels (r = 0.465, p = .034, and r = 0.463, p = .035, respectively). In conclusion, BAFF is the best circulating indicator to identify GD and HT among all chosen 29 biomarkers, and it could be used to predict the disease severity in HT and active GD. Meanwhile, IFN-α could be another reliable parameter for recognising HT.

Expression levels of interferon-ɣ and type 2 deiodinase in patients diagnosed with recurrent depressive disorders

BACKGROUND

Thyroid hormones (TH) are involved in modulation of the immune system and inflammation. TH dysregulation is associated with depressive disorders. The iodothyronine deiodinases (DIOs), the key enzymes for TH synthesis, can be affected and induced by pro-inflammatory cytokines. We aimed to investigate the levels of and correlation between type 2 DIO (DIO2) and interferon-gamma (IFN-ɣ) in patients with recurrent depressive disorders (rDD).

METHODS

Data from 91 rDD patients and 105 healthy controls were analyzed. The diagnoses are based on the ICD-10 criteria (F33.0-F33.8). Expression levels of DIO2 and IFN-ɣ were estimated using the method based on the polymerase chain reaction and the enzyme-linked immunosorbent assay (ELISA).

RESULTS

The DIO2 expression on mRNA/protein levels in rDD patients (both female and males) was reduced as compared with the control subjects. No correlation between DIO2 and IFN-ɣ expression was observed.

CONCLUSION

This is the first study to reveal that one may cautiously suggest that DIO2 may be involved in the development and/or progression of rDD. The mechanisms of TH regulation on depression, however, need further investigation.

The teleost head kidney: Integrating thyroid and immune signalling

The head kidney, analogous to the mammalian adrenal gland, is an organ unique for teleost fish. It comprises cytokine-producing lymphoid cells from the immune system and endocrine cells secreting cortisol, catecholamines, and thyroid hormones. The intimate organization of the immune system and endocrine system in one single organ makes bidirectional signalling between these possible. In this review we explore putative interactions between the thyroid and immune system in the head kidney. We give a short overview of the thyroid system, and consider the evidence for the presence of thyroid follicles in the head kidney as a normal, healthy trait in fishes. From mammalian studies we gather data on the effects of three important pro-inflammatory cytokines (TNFα, IL-1β, IL-6) on the thyroid system. A general picture that emerges is that pro-inflammatory cytokines inhibit the activity of the thyroid system at different targets. Extrapolating from these studies, we suggest that the interaction of the thyroid system by paracrine actions of cytokines in the head kidney is involved in fine-tuning the availability and redistribution of energy substrates during acclimation processes such as an immune response or stress response.

Evaluation of proinflammatory cytokine and neopterin levels in women with papillary thyroid carcinoma

INTRODUCTION

Papillary thyroid cancer is a disease that has been associated with chronic inflammation. The purpose of this study is to measure the production of the proinflammatory cytokines IL-1β, IL-6 and IL-8 and neopterin, which is a novel biomarker for cellular immune response in papillary thyroid cancer.

MATERIALS AND METHODS

The serum IL-1β, IL-6, IL-8 and neopterin values of 31 papillary thyroid cancer patients undergoing bilateral total thyroidectomy were measured before and 20 days after surgery. The values were compared with those of 39 healthy controls.

RESULTS

Serum IL-1β levels were similar across groups. IL-6 (p&lt;0.001), IL-8 (p = 0.015) and neopterin levels (p = 0.002) were higher in presurgical samples and returned to normal following surgery.

CONCLUSIONS

The proinflammatory cytokines IL-6 and IL-8, but not IL-1β, were produced in greater amounts in papillary thyroid cancer. Serum neopterin seems to be a valid biological marker supporting the presence of papillary thyroid cancer.

Pioglitazone, a PPARγ Agonist, Upregulates the Expression of Caveolin-1 and Catalase, Essential for Thyroid Cell Homeostasis: A Clue to the Pathogenesis of Hashimoto's Thyroiditis

BACKGROUND

Peroxisome proliferator-activated receptor γ (PPARγ) is a transcription factor that regulates the expression of multiple target genes involved in several metabolic pathways as well as in inflammation. The expression and cell localization of caveolin-1 (Cav-1), thyroperoxidase (TPO), and dual oxidase (DUOX), involved in extracellular iodination, is modulated by Th1 cytokines in human normal thyroid cells and in Hashimoto's thyroiditis (HT).

OBJECTIVES

The objectives of this study were (i) to analyze the PPARγ protein and mRNA expression at the follicular level in HT versus controls in correlation with the one of Cav-1; (ii) to study the effects of Th1 cytokines on PPARγ and catalase expression in human thyrocyte primary cultures; and (iii) to study the effects of pioglitazone, a PPARγ agonist, on thyroxisome components (Cav-1, TPO, DUOX) and on catalase, involved in antioxidant defense.

RESULTS

Although the global expression of PPARγ in the whole gland of patients with HT was not modified compared with controls, there was great heterogeneity among glands and among follicles within the same thyroid. Besides normal (type 1) follicles, there were around inflammatory zones, hyperactive (type 2) follicles with high PPARγ and Cav-1 expression, and inactive (type 3) follicles which were unable to form thyroxine and did not express PPARγ or Cav-1. In human thyrocytes in primary culture, Th1 cytokines decreased PPARγ and catalase expression; pioglitazone increased Cav-1, TPO, and catalase expression.

CONCLUSION

PPARγ may play a central role in normal thyroid physiology by upregulating Cav-1, essential for the organization of the thyroxisome and extracellular iodination. By upregulating catalase, PPARγ may also contribute to cell homeostasis. The inhibitory effect of Th1 cytokines on PPARγ expression may be considered as a new pathogenetic mechanism for HT, and the use of PPARγ agonists could open a new therapeutic approach.

Pro inflammatory interleukins and thyroid function in Naswar (dipping tobacco) users: a case control study

BACKGROUND

Naswar is a type of finely ground, moistened smokeless dipping tobacco product being commonly used in Pakistan. Although, nicotine is the most important psychoactive agent present in Naswar, it also exerts immunosuppressive effects and could alter the levels of cytokines. Additionally, the effects of Naswar consumption on thyroid hormones are not known.

METHODS

Eighty healthy males aged 16-43 years were selected for the study and were divided into a control group comprising 31 healthy subjects with no history of tobacco use in any form, with age matched test group comprising 49 exclusive Naswar users who were consuming Naswar for at least 1 year. Estimation of serum interleukin (IL)-1β, IL-6, free thyroxine (FT4), free triiodothyronine (FT3) and thyroid stimulating hormone (TSH) was carried out. The data was analyzed by statistical programme (SPSS) using student's independent samples t-test. One way Anova followed by post hoc Tukey test was applied to assess parameters in Naswar users grouped according to duration of Naswar usage. Pearson's correlation coefficient was applied to assess correlations between parameters.

RESULTS

IL-1β was found to be significantly lowered in Naswar users compared to the control group whereas serum FT3 and FT4 levels in Naswar users were significantly raised compared to the control group. However, no differences in the levels of serum IL-6 and TSH between Naswar users and the control group were found. Also, serum FT3 and FT4 were consistently raised whereas IL-1β was lowered in Naswar users irrespective of duration of Naswar consumption. IL-1β was negatively correlated with FT3 in Naswar users.

CONCLUSION

The findings suggest that Naswar users might be in an immune suppressive state as evident by the lowered levels of interleukin 1β. Additionally, alterations in the levels of thyroid hormones signify the impact of Naswar consumption on thyroid function.

Elevated interleukin-1β in peripheral blood mononuclear cells contributes to the pathogenesis of autoimmune thyroid diseases, especially of Hashimoto thyroiditis

PURPOSE OF THE STUDY

To explore the relationship between IL-1β expression and two common autoimmune thyroid diseases: Hashimoto thyroiditis (HT) and Graves' disease (GD).

MATERIALS AND METHODS

qRT-PCR, Quantiglo ELISA, and flow cytometry were used to evaluate the expression levels of IL-1β in serum, peripheral blood mononuclear cells (PBMCs), and thyroid tissue samples from patients with HT or GD. Local infiltration of monocytes was assessed by immunohistochemical study of patients' thyroid tissue samples.

RESULTS

Although no significant differences in IL-1β levels were found between samples of serum from patients with HT or GD and normal controls, we found that IL-1β mRNA and protein levels in PBMCs of HT patients were significantly higher than those of patients with GD, which were in turn higher than the level in normal controls. In addition, IL-1β mRNA was also increased in thyroid gland tissue from patients with HT compared to those with GD, and this was accompanied by increased local infiltration of monocytes into thyroid tissues. Correlation analysis of the clinical samples validated the association of high IL-1β levels with the pathogenesis of HT.

CONCLUSION

Our study suggests that IL-1β may be an active etiologic factor in the pathogenesis of HT and thus present a new target for novel diagnostics and treatment.

The Role of Hypothalamic NF-κB Signaling in the Response of the HPT-Axis to Acute Inflammation in Female Mice

A large proportion of critically ill patients have alterations in the hypothalamus-pituitary-thyroid (HPT) axis, collectively known as the nonthyroidal illness syndrome. Nonthyroidal illness syndrome is characterized by low serum thyroid hormone (TH) concentrations accompanied by a suppressed central component of the HPT axis and persistent low serum TSH. In hypothalamic tanycytes, the expression of type 2 deiodinase (D2) is increased in several animal models of inflammation. Because D2 is a major source of T3 in the brain, this response is thought to suppress TRH expression in the paraventricular nucleus via increased local bioavailability of T3. The inflammatory pathway component RelA (the p65 subunit of nuclear factor-κB) can bind the Dio2 promoter and increases D2 expression after lipopolysaccharide (LPS) stimulation in vitro. We aimed to determine whether RelA signaling in tanycytes is essential for the LPS-induced D2 increase in vivo by conditional elimination of RelA in tanycytes of mice (RelA(ASTKO)). Dio2 and Trh mRNA expression were assessed by quantitative in situ hybridization 8 or 24 hours after saline or LPS injection. At the same time points, we measured pituitary Tshβ mRNA expression and serum T3 and T4 concentrations. In RelA(ASTKO) mice the LPS-induced increase in Dio2 and decrease in Trh mRNA levels in the hypothalamus were reduced compared with the wild-type littermates, whereas the drop in pituitary Tshβ expression and in serum TH concentrations persisted. In conclusion, RelA is essential for the LPS-induced hypothalamic D2 increase and TRH decrease. The central changes in the HPT axis are, however, not required for the down-regulation of Tshβ expression and serum TH concentrations.

Prevalence and Influencing Factors of Thyroid Dysfunction in HIV-Infected Patients

Thyroid dysfunction is more common in human immunodeficiency virus (HIV) patients. But the effects of highly active antiretroviral therapy (HAART) and hepatitis B/C virus (HBV/HCV) coinfection on thyroid function is unclear. We retrospectively reviewed the data of 178 HIV patients and determined the prevalence of thyroid dysfunction and the relationship between thyroid hormone levels, CD4 cell count, HIV-1 duration, HAART duration/regimens, and HBV/HCV coinfection. Of the 178 patients, 59 (33.1%) had thyroid dysfunction, mostly hypothyroidism. Thyroid dysfunction was significantly more frequent in the HAART group (41/104, 39.4%) than in the HAART-naïve group (18/74, 24.3%; P < 0.05). The mean CD4 cell count was significantly lower in patients with hypothyroidism (372 ± 331/μL) than in the other patients (P < 0.05). The FT4 level was significantly lower in the HAART group than in the HAART-naïve group (1.09 ± 0.23 versus 1.20 ± 0.29 pg/mL, P < 0.05). FT3/FT4 levels were negatively related to HIV duration and FT3 levels were positively related to CD4 cell (P < 0.05). HBV patients had lower FT3 levels, while HCV patients had higher FT3 and FT4 levels (P < 0.05). Thyroid dysfunction is more common in HIV patients on HAART, mainly manifested as hypothyroidism. FT3/FT4 levels are correlated with HIV progression. HBV/HCV coinfection increases the probability of thyroid dysfunction.

Distinct Features of Nonthyroidal Illness in Critically Ill Patients With Infectious Diseases

Nonthyroidal illness (NTI), often observed in critically ill patients, arises through diverse alterations in the hypothalamus-pituitary-thyroid (HPT) axis. However, the causal relationship between underlying disease and NTI diversity in critically ill patients is poorly understood.The aim of this study was to examine NTI severity and adverse outcomes in critically ill patients with respect to their underlying disease(s).The medical records of 616 patients admitted to the intensive care unit (ICU) between January 2009 and October 2014 were retrospectively reviewed. Patients with known diseases or taking medications that affect thyroid function were excluded. All-cause mortality (ACM) and length of stay (LOS) in the ICU were assessed as adverse outcomes.The enrolled patients (n = 213) were divided into the following 4 groups according to the severity of NTI at the nadir of their thyroid function test (TFT): normal (n = 11, 5.2%), mild NTI (n = 113, 53.1%), moderate NTI (n = 78, 36.6%), and severe NTI (n = 11, 5.2%). There was no significant difference between the groups in terms of age and gender. NTI severity showed a significantly strong association with ACM (P < 0.0001) and a significant positive association with LOS in the ICU (P = 0.031). After adjusting for age, gender, and current medications affecting TFT, increasing NTI severity led to increased ACM (odds ratio = 3.101; 95% confidence interval = 1.711-5.618; P < 0.0001). Notably, the prevalence of moderate-to-severe NTI was markedly higher in patients with infectious disease than in those with noninfectious disease (P = 0.012). Consistent with this, serum C-reactive protein levels were higher in patients with moderate-to-severe NTI (P = 0.016).NTI severity is associated with increased ACM, LOS, and underlying infectious disease. Future studies will focus on the biological and clinical implications of infectious disease on the HPT axis.

Low T3 syndrome is a strong predictor of poor outcomes in patients with community-acquired pneumonia

Low T3 syndrome was previously reported to be linked to poor clinical outcomes in critically ill patients. The aim of this study was to evaluate the predictive power of low T3 syndrome for clinical outcomes in patients with community-acquired pneumonia (CAP). Data for 503 patients were analyzed retrospectively, and the primary end point was 30-day mortality. The intensive care unit (ICU) admission rate and 30-day mortality were 8.3% and 6.4% respectively. The prevalence of low T3 syndrome differed significantly between survivors and nonsurvivors (29.1% vs 71.9%, P < 0.001), and low T3 syndrome was associated with a remarkable increased risk of 30-day mortality and ICU admission in patients with severe CAP. Multivariate logistic regression analysis produced an odds ratio of 2.96 (95% CI 1.14–7.76, P = 0.025) for 30-day mortality in CAP patients with low T3 syndrome. Survival analysis revealed that the survival rate among CAP patients with low T3 syndrome was lower than that in the control group (P < 0.01). Adding low T3 syndrome to the PSI and CURB-65 significantly increased the areas under the ROC curves for predicting ICU admission and 30-day mortality. In conclusion, low T3 syndrome is an independent risk factor for 30-day mortality in CAP patients.

The molecular basis of the non-thyroidal illness syndrome

The 'sick euthyroid syndrome' or 'non-thyroidal illness syndrome' (NTIS) occurs in a large proportion of hospitalized patients and comprises a variety of alterations in the hypothalamus-pituitary-thyroid (HPT) axis that are observed during illness. One of the hallmarks of NTIS is decreased thyroid hormone (TH) serum concentrations, often viewed as an adaptive mechanism to save energy. Downregulation of hypophysiotropic TRH neurons in the paraventricular nucleus of the hypothalamus and of TSH production in the pituitary gland points to disturbed negative feedback regulation during illness. In addition to these alterations in the central component of the HPT axis, changes in TH metabolism occur in a variety of TH target tissues during NTIS, dependent on the timing, nature and severity of the illness. Cytokines, released during illness, are known to affect a variety of genes involved in TH metabolism and are therefore considered a major determinant of NTIS. The availability of in vivo and in vitro models for NTIS has elucidated part of the mechanisms involved in the sometimes paradoxical changes in the HPT axis and TH responsive tissues. However, the pathogenesis of NTIS is still incompletely understood. This review focusses on the molecular mechanisms involved in the tissue changes in TH metabolism and discusses the gaps that still require further research.

Increased expression of IL-37 in patients with Graves' disease and its contribution to suppression of proinflammatory cytokines production in peripheral blood mononuclear cells

Background

Intreleukin-37 (IL-37), a member of IL-1 family, is primarily an anti-inflammatory cytokine, which reduces systemic and local inflammation. However, the expression and role of IL-37 in Graves' disease (GD) remains unknown. This study aims to measure the levels of serum and peripheral blood mononuclear cells (PBMCs) IL-37 in patients with Graves' disease and to examine its association with disease activity. Furthermore, we investigate the effect of IL-37 on proinflammatory cytokines involved in the pathogenesis of GD.

Methods

The expressions of IL-37, TNF-α, IL-6, and IL-17 mRNA in peripheral blood mononuclear cells (PBMCs) of 40 patients with Graves' disease were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR), and the levels of IL-37, TNF-α, IL-6, and IL-17 in serum were detected by enzyme-linked immunoassay (ELISA). The correlation of serum IL-37 levels with cytokines and disease activity in Graves' disease patients were investigated. The expressions of cytokines TNF-α, IL-6, and IL-17 in PBMCs under recombinant IL-37 stimulation were determined by RT-PCR and ELISA respectively.

Results

The levels of IL-37, TNF-α, IL-6, and IL-17 in PBMCs and serum were significantly increased in patients with GD compared with healthy controls (HC). Serum IL-37 were closely correlated with TNF-α, IL-6, IL-17, thyrotropin (TSH), free thyroxine (FT4),free triiodothyronine (FT3) and thyrotropin receptor antibody (TRAB). GD patients with active disease showed higher IL-37 mRNA and serum protein levels compared with those with inactive disease as well as HC. Moreover, IL-37 suppressed the production of IL-6, IL-17 and TNF-α in PBMCs of patients with GD.

Conclusions

Increased level of IL-37 in patients with GD are associated with TNF-α, IL-6, IL-17 and disease activity, and it plays a protective role against inflammatory effect in GD by inhibiting the production of proinflammatory cytokines. Thus, IL-37 may provide a novel research target for the pathogenesis and therapy of GD.

Differential regulation of the production of reactive oxygen species in Th1 cytokine-treated thyroid cells

BACKGROUND

Th1 cytokines exert pleiotropic effects in Hashimoto's thyroiditis. Previous studies reported a downregulation of thyroperoxidase and dual oxidase (DUOX) protein and mRNA expression in thyroid cells treated with Th1 cytokines. Although this effect is partially mediated by intracellular reactive oxygen species (ROS) and reactive nitrogen species, the nature and the source of the ROS involved are currently unknown. The aim of this study was to examine further the nature and source of the ROS produced in response to Th1 cytokines.

METHODS

Two rat thyroid cell lines (PCCL3 and FRTL-5) and human thyrocytes were incubated with Th1 cytokines (interleukin [IL]-1α and interferon-γ) in the presence or absence of the Th2 cytokine IL-4, the nitric oxide synthase inhibitor N-nitroso-L-arginine methyl ester (L-NAME), or the synthetic antioxidant N-acetylcysteine. The nature and source of the intracellular and extracellular ROS produced were determined.

RESULTS

A rapid increase in intracellular ROS was observed in cells incubated with Th1 cytokines. This increase was not caused by extracellular hydrogen peroxide (H2O2) produced by DUOX because both DUOX expression and extracellular H2O2 synthesis were decreased by Th1 cytokines. Confocal colocalization experiments showed that the Th1 cytokine-triggered ROS were not produced from mitochondria. Electron paramagnetic resonance investigations of PCCL3 cells indicated that the highly reactive hydroxyl radical was not involved in the response to Th1 cytokines. NOX2 mRNA expression was significantly increased in PCCL3 cells incubated with Th1 cytokines, as was the expression of the protein in the thyroid of Hashimoto's thyroiditis patients. NOX4 expression was by contrast unaffected. These results suggest that at least superoxide could be produced after exposure of thyroid cells to Th1 cytokines. The effects of L-NAME and IL-4, both of which partially or totally reverse Th1 cytokine-induced effects, on ROS release were also analyzed. L-NAME and IL-4 significantly reduced the Th1 cytokine-induced surge of intracellular ROS in PCCL3 and human thyroid cells.

CONCLUSION

The data presented here reinforce the idea that ROS, other than extracellular H2O2 produced by DUOX, are released from NOX2 after exposure of thyroid cells to Th1 cytokines. ROS/reactive nitrogen species act as important, but as further explained, not exclusive intracellular mediators of Th1 cytokine-induced effects in thyroid cells.

Autoimmune thyroid disorders in hepatitis C virus infection: Effect of interferon therapy

The hepatitis C virus infection represents an important public health problem and is associated with various hepatic and extrahepatic manifestations. Symptoms outside of the liver can occur in multiple organ systems, including hematologic, renal, dermatologic, endocrine, and rheumatologic systems. Among these different organ systems, special attention has focused on the endocrine system because it affects almost every organ in the body. Among the endocrine disorders, thyroid problems are the most common and the thyroid is one of the principal target organs for extrahepatic manifestations in HCV infected patients. In addition, research data suggest that interferon treatment may be associated with immune-mediated thyroid lesions. However, case reports suggest that the response of thyroid extrahepatic manifestations to interferon in patients with chronic HCV is greatly different. The objective of this study was to summarize currently available data on thyroid conditions associated with chronic HCV infection. Moreover, we investigate the incidence of the development of immune mediated thyroid disorders during interferon therapy in these patients.

Innate immune activation and thyroid autoimmunity

CONTEXT

Autoimmune thyroid disease (AITD) is the archetypal organ-specific autoimmune disorder and is characterized by the production of thyroid autoantibodies. However, the underlying mechanisms by which specific antibodies against thyroid proteins are produced are largely unknown.

EVIDENCE ACQUISITION

Published peer-reviewed basic and clinical literatures on immunology and autoimmune diseases were identified through searches of PubMed for articles published from January 1971 to May 2011. Articles resulting from these searches and relevant references cited in those articles were reviewed. All the relevant articles were written in English.

EVIDENCE SYNTHESIS

Recent studies have indicated that innate immune responses induced by both exogenous and endogenous factors affect the phenotype and severity of autoimmune reactions. One of the recent topics is the effect of self-genomic DNA fragments on immune activation. Expression of major histocompatibility complex class II on the autoimmune target cells seems to play an important role in the presentation of endogenous antigens. Accumulated evidence from animal models has generated new insights into the pathogenesis of AITD.

CONCLUSION

AITD develops by a combination of genetic susceptibility and environmental factors. Innate immune responses are associated with thyroid dysfunction, tissue destruction, and the likely development and perpetuation of AITD. In addition to the other factors, cell injury may contribute to the activation of innate immune response and the development of AITD.

Beyond low plasma T3: local thyroid hormone metabolism during inflammation and infection

Decreased serum thyroid hormone concentrations in severely ill patients were first reported in the 1970s, but the functional meaning of the observed changes in thyroid hormone levels, together known as nonthyroidal illness syndrome (NTIS), remains enigmatic. Although the common view was that NTIS results in overall down-regulation of metabolism in order to save energy, recent work has shown a more complex picture. NTIS comprises marked variation in transcriptional and translational activity of genes involved in thyroid hormone metabolism, ranging from inhibition to activation, dependent on the organ or tissue studied. Illness-induced changes in each of these organs appear to be very different during acute or chronic inflammation, adding an additional level of complexity. Organ- and timing-specific changes in the activity of thyroid hormone deiodinating enzymes (deiodinase types 1, 2, and 3) highlight deiodinases as proactive players in the response to illness, whereas the granulocyte is a novel and potentially important cell type involved in NTIS during bacterial infection. Although acute NTIS can be seen as an adaptive response to support the immune response, NTIS may turn disadvantageous when critical illness enters a chronic phase necessitating prolonged life support. For instance, changes in thyroid hormone metabolism in muscle during critical illness may be relevant for the pathogenesis of myopathy associated with prolonged ventilator dependence. This review focuses on NTIS as a timing-related and organ-specific response to illness, occurring independently from the decrease in serum thyroid hormone levels and potentially relevant for disease progression.

A case report of subacute thyroiditis during pregnancy: difficulties in differential diagnosis and changes in cytokine levels

INTRODUCTION

Thyroid dysfunction during pregnancy may result in both maternal and neonatal complications. Subacute thyroiditis (SAT) is an extremely rare cause of both hyper- and hypothyroidism in pregnant women.

CASE DESCRIPTION

A case of first trimester SAT is presented. Diagnosis of SAT was based on fine-needle aspiration biopsy. The disease resolved spontaneously without need for prednisone administration but a hypothyroid phase treated with T4 throughout pregnancy occurred. The pregnancy resulted in a healthy full term infant. We measured various cytokine levels in an attempt to follow their course during SAT as well as throughout the remaining period of pregnancy. Serum thyreoglobulin (Tg) levels correlated best with thyroid function tests (TFTs) and the course of SAT.

CONCLUSIONS

The diagnosis of SAT at a pregnancy setting may be intriguing. The measurement of circulating cytokines is not helpful in the differential diagnosis or monitoring of the disease.

Fragments of genomic DNA released by injured cells activate innate immunity and suppress endocrine function in the thyroid

Activation of innate and acquired immune responses, which can be induced by infection, inflammation, or tissue injury, may impact the development of autoimmunity. Although stimulation of cells by double-stranded DNA (dsDNA) has been shown to activate immune responses, the role of self-genomic DNA fragments released in the context of sterile cellular injury is not well understood. Using cultured thyroid cells, we show that cell injury prompts the release of genomic DNA into the cytosol, which is associated with the production of type I interferons, inflammatory cytokines, and chemokines. Molecules necessary for antigen processing and presentation to lymphocytes are also induced in thyroid cells by injury. dsDNA strongly suppressed the expression of sodium/iodide symporter and radioiodine uptake. To identify molecules responsible for sensing cytosolic dsDNA, we directly identified the cellular proteins that bound a dsDNA Sepharose column by mass spectrometry. Our analysis identified histone H2B, which was previously demonstrated to be an essential factor that mediates the activation of innate immunity induced by dsDNA. Knockdown of histone H2B using specific small interfering RNA abolished cell injury-induced innate immune activation and increased sodium/iodide symporter expression. These results indicate that genomic DNA fragments released by cell injury are recognized by extrachromosomal histone H2B, which results in the activation of genes involved in both innate and acquired immune responses in thyroid cells and suppression of thyroid function. These results suggest that sterile thyroid injury, in the absence of infection, may be sufficient to trigger autoimmune reaction and to induce thyroid dysfunction.

Unusual cause of weight loss in a patient with HIV-hepatitis C virus coinfection

Recombinant interferon α (IFN α), alone or in combination, is used extensively in the treatment of hepatitis C infection. IFN therapy is not free of side-effects and autoimmune thyroiditis is one of its rare side-effects. We present here a case of a patient with hepatitis C virus-human immunodeficiency virus coinfection on interferon therapy who presented with significant weight loss. He was found to have IFN-related autoimmune thyrotoxicosis and responded to antithyroid drugs and propanolol. Therefore, this case highlights that IFN-induced thyroiditis is an unusual side-effect and that during treatment, a thyroid-stimulating hormone assay should be performed at regular intervals (every 8-12 weeks).

N-acetylcysteine and 15 deoxy-{delta}12,14-prostaglandin J2 exert a protective effect against autoimmune thyroid destruction in vivo but not against interleukin-1{alpha}/interferon {gamma}-induced inhibitory effects in thyrocytes in vitro

Reactive oxygen species (ROS) are crucial for thyroid hormonogenesis, and their production is kept under tight control. Oxidative stress (OS) is toxic for thyrocytes in an inflammatory context. In vitro, Th1 pro-inflammatory cytokines have already been shown to decrease thyroid-specific protein expression. In the present study, OS level and its impact on thyroid function were analyzed in vitro in Th1 cytokine (interleukin [IL]-1alpha/interferon [IFN] gamma)-incubated thyrocytes (rat and human), as well as in vivo in thyroids from nonobese diabetic mice, a model of spontaneous autoimmune thyroiditis. N-acetylcysteine (NAC) and prostaglandin, 15 deoxy-(Delta12,14)-prostaglandinJ2 (15dPGJ2), were used for their antioxidant and anti-inflammatory properties, respectively. ROS production and OS were increased in IL-1alpha/IFNgamma-incubated thyrocytes and in destructive thyroiditis. In vitro, NAC not only reduced ROS production below control levels, but further decreased the expression of thyroid-specific proteins in addition to IL-1alpha/IFNgamma-inhibitory effects. Thus, besides ROS, other intracellular intermediaries likely mediate Th1 cytokine effects. In vivo, NAC and 15dPGJ2 reduced OS and the immune infiltration, thereby leading to a restoration of thyroid morphology. It is therefore likely that NAC and 15dPGJ2 mainly exert their protective effects by acting on infiltrating inflammatory cells rather than directly on thyrocytes.

Iodide-induced chemokines and genes related to immunological function in cultured human thyroid follicles in the presence of thyrotropin

BACKGROUND

It is well known that iodide exacerbates thyroid function in subclinical hypothyroid patients with autoimmune thyroiditis. To investigate the immunological mechanism of iodine-induced thyroid dysfunction, we studied the effect of iodide in cultured human thyroid follicles, which respond to physiological concentrations of human thyrotropin (TSH) (0.3-10 microU/mL) and maintain the Wolff-Chaikoff effect.

MATERIALS AND METHODS

Thyroid follicles obtained from Graves' patients at subtotal thyroidectomy were precultured in medium containing 0.5% fetal calf serum and 10(-8) M iodide for 5 days, and then cultured with the medium containing bovine TSH (30 microU/mL) and low (10(-8)M) or high (10(-5)M) concentrations of iodide. After 3-72 hours of culture, the effect of iodide on thyroid cell mRNA expression was analyzed by microarray and reverse transcriptase-polymerase chain reaction.

RESULTS

After 48 hours of culture, iodide nearly doubled the mRNA expression levels of the immunity-associated genes (intercellular adhesion molecule-1, transforming growth factor beta 1-induced protein, early growth response gene 1, guanylate-binding protein 1, and annexin A1) and decreased the mRNA expression of sodium-iodide symporter to less than 20%. Further, the mRNA expression levels of chemokines (CCL2, CXCL8, and CXCL14) increased nearly twofold, whereas their receptors did not show any significant response. Real-time polymerase chain reaction analyses confirmed that iodide increased the mRNA expression levels of these genes in a time- and concentration-dependent manner. Immunohistochemical studies revealed that the chemokines were expressed mainly in the thyroid follicular cells in addition to the immune cells. The iodide-induced increase in CCL2 was greater in thyroid follicles obtained from thyroid gland that had been moderately infiltrated with the immunocompetent cells.

CONCLUSION

We have demonstrated that iodide stimulates thyroid follicular cells to produce chemokines, particularly CCL2, CXCL8, and CXCL14. These chemokines and intercellular adhesion molecule-1 would attract immunocompetent cells into thyroid gland. These in vitro findings suggest that iodide at high concentrations may induce thyroid dysfunction through not only biochemical but also immunological mechanisms, particularly in patients with autoimmune thyroid disorders.

Interferon-induced thyroid dysfunction in chronic hepatitis C

BACKGROUND

Treatment of chronic hepatitis C with interferon is known to be associated with thyroid dysfunction (TD) in 5-14% of patients. We studied the incidence, types, outcome and risk factors predictive of thyroid dysfunction.

METHODS

A retrospective analysis was performed on all patients treated with interferon alpha (IFN) or pegylated interferon alpha (PEG-IFN) +/- ribavirin (RBV), who developed abnormal thyroid function tests (TFTs). These cases were compared with treatment-matched controls to identify factors predictive of thyroid dysfunction. Statistical methods consisted of: chi(2) test, Fischer's exact test, Welch's t-test, and multivariate analysis.

RESULTS

From a total of 511 patients, 45 cases with TD were identified (8.8%). Pegylated interferon alpha was associated with higher rates of TD than IFN (14.1% vs 6.0%, P = 0.0029). Female sex (OR 5.6, 95% CI 1.1-7) and Asian ethnicity (OR 2.7, 95% CI 1.4-22) were independent predictors of developing TD. Cytology was obtained in 13 patients: benign follicular pattern (8); thyroiditis (3); and normal (2). Thyroid peroxidase (TPO) antibodies (P = 0.004) and earlier onset of dysfunction (P = 0.03) were associated with need for treatment. Sixteen patients had persistent TD by the end of the follow-up period, predicted by female sex, non-Asian ethnicity, prior history of TD and TPO antibodies.

CONCLUSIONS

Pegylated interferon alpha, female sex and Asian ethnicity are independent risk factors for TD. Thyroid peroxidase antibodies and earlier TD within the course of IFN are associated with the requirement for treatment. Thyroid function tests should be monitored during and after IFN-based therapy. The most common cytological finding is a benign follicular pattern.

Influence of iodide excess and interferon-gamma on human primary thyroid cell proliferation, thyroglobulin secretion, and intracellular adhesion molecule-1 and human leukocyte antigen-DR expression

BACKGROUND

The effect of iodide on thyroid cell proliferation and function in vivo or in cultured thyroid cells has been previously reported and is still controversial. The aim of this study was to clarify these conflicting results by examining if prolonged high iodide exposition with or without interferon (IFN)-gamma has an effect on human primary thyroid cell proliferation, thyroglobulin (Tg) production, and intercellular adhesion molecule-1 (ICAM-1) and human leukocyte antigen (HLA)-DR expression.

METHODS

Primary human thyroid cells were used. Cells were cultured in Coon's modified Ham's F-12 medium supplemented with 5% fetal calf serum in monolayer conditions to induce proliferation and were aggregated for molecular expression and Tg production analysis. HLA-DR and ICAM-1 expression were measured by flow cytometry and Tg by immunometric assay.

RESULTS

Potassium iodide (KI) was more potent in arresting primary human thyroid cell proliferation as compared to sodium iodide and the effect was mediated by its action at G0/G1 and G2/M phases of the cell cycle. There were no signs of apoptosis or necrosis. An excess of KI alone did not change the expression of HLA-DR and Tg production, but gradually increased ICAM-1. Low-dose IFN-gamma and excess KI in combination transiently inhibited HLA-DR expression, while ICAM-1 was expressed at a higher level than with IFN-gamma alone. Tg production was moderately increased with low-dose IFN-gamma. However, a combination of high-dose KI with low-dose IFN-gamma significantly decreased Tg secretion, compared with IFN-gamma alone.

CONCLUSIONS

Augmented ICAM-1 in the presence of iodide excess and low-dose IFN-gamma could induce secretion of proinflammatory cytokines and lymphocytic infiltration in the thyroid gland. Decreased Tg production in the presence of KI excess and IFN-gamma could explain the development of hypothyroidism after adding iodide in a diet of subjects that already have lymphocytic infiltration and/or mild inflammation in the thyroid gland.

Cytokines, Graves' disease, and thyroid-associated ophthalmopathy

Graves' disease, an autoimmune process associated with thyroid dysfunction, can also manifest as remodeling of orbital connective tissue. Affected tissues exhibit immune responses that appear to be orchestrated by resident cells and those recruited from the bone marrow through their expression and release of cytokines and surface display of cytokine receptors. Cytokines are small molecules produced by many types of cells, including those of the "professional" immune system. Aberrant cytokine expression appears to play an important role in the pathogenesis of many human diseases, including thyroid autoimmunity. The skewed pattern of cytokine expression in the thyroid, including the T helper cell bias, may condition the response to apoptotic signals and determine the characteristics of an autoimmune reaction. Furthermore, chemoattractant cytokines, including IL16, RANTES, and CXCL10, elaborated by resident cells in the thyroid and orbit may provoke mononuclear cell infiltration. Other cytokines may drive cell activation and tissue remodeling. Thus cytokines and the signaling pathways they activate represent attractive therapeutic targets. Interruption of these might alter the natural course of Graves' disease and its orbital manifestations.

Interferon alpha treatment and thyroid dysfunction

Interferon alpha (IFN alpha) is the cornerstone therapeutic agent for chronic hepatitis C virus (HCV) infection. Prospective studies have shown that up to 15% of HCV patients receiving IFN alpha develop clinical thyroid disease, and up to 40% become thyroid antibody positive. In some cases IFN-induced thyroiditis (IIT) may result in discontinuation of interferon therapy; thus, IIT represents a major clinical problem for hepatitis C patients receiving IFN alpha therapy. Recently, the mechanisms leading to the development of IIT have begun to be unraveled. It is now clear that HCV itself plays a role in the disease. Moreover, recent data suggest the IFN alpha precipitates thyroiditis by both immune modulatory mechanisms and direct thyroid toxic effects. Genetic factors also play a major role in the etiology of IIT. IIT can manifest both as clinical autoimmune thyroiditis (ie, Hashimoto's thyroiditis and Graves' disease) and as nonautoimmune thyroiditis (ie, destructive thyroiditis). Early detection and therapy of these conditions are important to avoid complications of thyroid disease such as cardiac arrhythmias. This article reviews the epidemiology and clinical manifestations of IIT and the mechanisms causing IIT, focusing on the role of HCV.

Suppression of iodide uptake and thyroid hormone synthesis with stimulation of the type I interferon system by double-stranded ribonucleic acid in cultured human thyroid follicles

Although viral infection is thought to be associated with subacute thyroiditis and probably with autoimmune thyroid disease, possible changes in thyroid function during the prodromal period of infection or subclinical infection remain largely unknown. Recently, it was shown that pathogen-associated molecular patterns stimulate Toll-like receptors (TLR) and activate innate immune responses by producing type I interferons (IFN). Using a human thyroid follicle culture system, in which de novo synthesized thyroid hormones are released into the culture medium under physiological concentrations of human TSH, we studied the effects of polyinosinic-polycytidylic acid [Poly(I:C)], a chemical analog of viral double-stranded RNA (dsRNA), on TSH-induced thyroid function. Thyrocytes expressed ligands for dsRNA (TLR 3, CD14, and retinoic-acid-inducible protein-1) comparable with the TSH receptor. DNA microarray and real-time PCR analyses revealed that dsRNA increased the expression of mRNA for TLR3, IFN-beta, IFN-regulating factors, proinflammatory cytokines, and class I major histocompatibility complex (MHC), whereas genes associated with thyroid hormonogenesis (sodium/iodide symporter, peroxidase, deiodinases) were suppressed. In accordance to these data, Poly(I:C) suppressed TSH-induced 125I uptake and hormone synthesis dose dependently, accompanied by a decrease in the ratio of 125I-T3/125I-T4 released into the culture medium, whereas peptidoglycan, lipopolysaccharides, or unmethylated CpG DNA, ligands for TLR2, TLR4, and TLR9, respectively, had no significant effect. These inhibitory effects of Poly(I:C) were not blocked by a neutralizing antibody against TLR3 and an anti-IFN alpha/beta receptor antibody. These in vitro findings suggest that when thyrocytes are infected with certain viruses, dsRNA formed intracellularly in thyrocytes may be a cause for thyroid dysfunction, leading to development of autoimmune thyroiditis.

Iodide inhibits vascular endothelial growth factor-A expression in cultured human thyroid follicles: a microarray search for effects of thyrotropin and iodide on angiogenesis factors

OBJECTIVE

Excess iodide has been administered to hyperthyroid patients before thyroid surgery to reduce intraoperative bleeding and oozing. The purpose of this study was to elucidate the mechanism by which iodide reduces blood flow in the hypervascular thyroid gland.

DESIGN

Human thyroid follicles were cultured in the presence or absence of thyrotropin (TSH), or in medium containing various concentrations of iodide, and TSH-or iodide-regulated gene expression was analyzed by cDNA microarray.

MAIN OUTCOME

TSH stimulated the expression of thyroglobulin, peroxidase, sodium iodide symporter, vascular endothelial growth factor (VEGF)-A, VEGF-B, and placental growth factor (PGF) but decreased that of VEGF-C by half. When thyroid follicles were cultured in high-iodide (10(5) M) medium, TSH-induced expression of VEGF-A, VEGF-B, and PGF was decreased, accompanied by a reduction of VEGF-A release into the medium. Furthermore, expression of putative angiogenesis inhibitors such as urokinase-type plasminogen activator (PLAU) was increased. These findings were confirmed by real-time polymerase chain reaction (PCR) and Northern blot hybridization.

CONCLUSIONS

We have demonstrated for the first time that iodide at high concentration decreases the expression of the angiogenic factors VEGF-A, VEGF-B, and PGF, accompanied by an increase in the expression of possible antiangiogenic factors such as PLAU. These proangiogenic and antiangiogenic factors may at least partly account for the iodide-induced decrease in thyroid blood flow.

Thyroid function in human immunodeficiency virus patients treated with highly active antiretroviral therapy (HAART): a longitudinal study

OBJECTIVE

Given that few and controversial data have been reported on thyroid function in human immunodeficiency virus (HIV) patients on highly active antiretroviral therapy (HAART), we further investigated whether HAART affects thyroid hormones.

DESIGN AND PATIENTS

Two hundred two consecutive adult HIV patients in stable clinical condition were enrolled, 182 on HAART and 20 naïve; 128 were rechecked during follow-up. Body mass index (BMI), CD4 cell count, HIV RNA, hepatitis C and B virus status and infection duration were determined in all HIV patients and HAART duration in treated patients. In all patients and in 60 controls, the following were measured: FT4 and FT3 by radioimmunoassay; TSH, antithyroid peroxidase (TPO) and antithyroglobulin (TG) antibodies by immunoradiometric assay.

RESULTS

Abnormalities in thyroid function tests were found in 23/182 (12.6%) HAART patients, but not in naïve patients. Most abnormalities were subclinical hypothyroidism, with mean FT4 and TSH levels lower and higher, respectively, in HAART patients compared to naïve patients and controls, FT4 levels being significantly lower than controls. TSH negatively correlated with CD4 count nadir and positively with HAART duration. During follow-up, FT4 and FT3 significantly decreased and TSH increased in patients continuing HAART, whereas CD4 counts were unmodified; subclinical hypothyroid conditions persisted and further cases occurred, whereas the only hypothyroid patient who interrupted HAART shows a normalization of thyroid tests. Patients on stavudine, included in most hypothyroid patient protocols, had significantly lower FT4 levels with prolonged treatment.

CONCLUSIONS

HAART, particularly stavudine, is associated with a high prevalence of subclinical hypothyroidism. Hypotheses are made regarding responsible mechanisms and risk factors. Thyroid function should be tested and sequentially rechecked in HAART patients.

The clinical and physiological spectrum of interferon-alpha induced thyroiditis: toward a new classification

Interferon-alpha (IFNalpha) is a major treatment modality for several malignant and nonmalignant diseases, especially hepatitis C. Prospective studies have shown that up to 15% of patients with hepatitis C receiving IFNalpha develop clinical thyroid disease, and up to 40% were reported to develop thyroid antibodies. Some of these complications may result in discontinuation of interferon therapy. Thus, interferon induced thyroiditis (IIT) is a major clinical problem for patients receiving interferon therapy. IIT can be classified as autoimmune type and non-autoimmune type. Autoimmune IIT may manifest by the development of thyroid antibodies without clinical disease, or by clinical disease which includes both autoimmune hypothyroidism (Hashimoto's thyroiditis) and autoimmune thyrotoxicosis (Graves' disease). Non-autoimmune IIT can manifest as destructive thyroiditis or as hypothyroidism with negative thyroid antibodies. Early detection and therapy of these conditions is important in order to avoid complications of thyroid disease such as cardiac arrhythmias. While it is not clear which factors contribute to the susceptibility to IIT, recent evidence suggests that genetic factors, gender, and hepatitis C virus infection may play a role. In contrast, viral genotype and therapeutic regimen do not influence susceptibility to IIT. The etiology of IIT is unknown and may be secondary to immune modulation by IFNalpha and/or direct effects of interferon on the thyroid. In this review we discuss the clinical and pathophysiological aspects of IIT, and we are proposing a new, etiology-based classification of IIT, as well as an algorithm for diagnosis and treatment of IIT.

Thyroid dysfunction in patients with chronic hepatitis C receiving a combined therapy of interferon and ribavirin: incidence, associated factors and prognosis

BACKGROUND AND AIMS

Interferon (IFN) plus ribavirin therapy for chronic hepatitis C (CHC) virus infection has been associated with thyroid dysfunction. The goal of our current study was to elucidate predictive factors of: (i) thyroid dysfunction associated with combination therapy; and (ii) long-term reversibility of thyroid dysfunction.

METHODS

In total, 461 patients with CHC and normal baseline thyroid functions were enrolled. All patients received IFN-alpha-2b, 3 or 5 million units thrice weekly, or pegylated (PEG)-IFN-alpha-2b 80 or 100 microg weekly combined with ribavirin 1-1.2 g daily for 24-48 weeks. Assays for serum thyroid stimulating hormone (TSH) and free thyroxine were performed.

RESULTS

By the end of the treatment, thyroid dysfunction (TSH <0.1 or >5 mU/L) had developed in 58 patients (12.6%). Female gender was significantly associated with thyroid dysfunction (P < 0.001 odds ratio (OR) = 2.85; 95% confidence interval (CI) = 1.6-5.1). The incidence of thyroid dysfunction was similar for standard IFN and PEG-IFN-treated patients (49/391 vs 9/70; P = 1.00). Under a nested case-control design, detailed laboratory assessment was carried out on frozen serum samples from patients and age- (+/- 5 years) and sex-matched controls (n = 58). Multivariate analysis revealed significant association between higher positive rates of pretreatment TMA and patients who developed thyroid dysfunction (OR = 5.8, 95% CI = 1.2-27.9). Ten patients ( approximately 2%) remained thyroid dysfunctional at the end of follow up (median, 26.5 months). For these patients, no risk factor can predict the reversibility of thyroid function.

CONCLUSIONS

Female gender and pretreatment TMA positivity are associated with thyroid dysfunction. Long-term thyroid dysfunction may persist in a small group of patients ( approximately 2%).

Thyrocytes isolated from autoimmune-diseased thyroids secrete soluble tumor necrosis factor-R1 that is related to their elevated protein kinase C activity

Soluble tumor necrosis factor (TNF)-alpha receptors have the potential to modulate TNF-alpha activity during autoimmune thyroiditis. In this study we examined cell-surface TNF-alpha receptors and soluble TNF-alpha receptor production by thyrocytes from normal and MRL-lpr(-/-) (diseased) mice, which spontaneously develop autoimmune thyroiditis. We found that murine thyrocytes possess the 55-kd receptor (TNF-R1). Examination of soluble TNF-R1 production revealed that diseased thyrocytes produced sevenfold more soluble TNF-R1 than normal thyrocytes. Furthermore, basal protein kinase C (pKC) activity in diseased thyrocytes was 67% higher than that found in normal murine thyrocytes. The elevated basal pKC activity in diseased thyrocytes was related to their enhanced production of soluble TNF-R1 because inhibition of pKC activity with calphostin C caused soluble TNF-R1 production to decrease significantly. Additionally, soluble TNF-R1 production by murine thyrocytes was not a result of cell-surface receptor shedding but through secretion of a truncated version of TNF-R1. This was evident when cell-surface TNF-R1 levels were unchanged after treatment of diseased thyrocytes with calphostin C. Also, the 28-kd form of TNF-R1, which corresponds to the soluble receptor, was present in the intracellular membranes of the diseased thyrocytes.

Relationship between circulating cytokine levels and thyroid function following bone marrow transplantation

The relation between thyroid hormone changes and cytokines in bone marrow transplantation (BMT) patients has not been studied. This prospective study was designed to determine the relation between thyroid hormones and cytokine levels after BMT and their effects on the mortality. We studied 80 patients undergoing allogeneic BMT. Serum thyroid hormone parameters and cytokine levels were measured before and serially during 6 months after BMT. Serum T(3) decreased to a nadir 3 weeks post-BMT and serum T(4) was lowest at 3 months post-BMT. Serum thyroid stimulating hormone (TSH) sharply decreased to a nadir at 1 week and recovered. Serum interleukin-6 increased for 2 weeks after BMT and declined thereafter. Serum tumor necrosis factor-alpha increased for 3 weeks after BMT and declined thereafter. After 3 weeks post-BMT, both cytokine levels were negatively correlated with serum T(3) and T(4) levels. A total of 29 patients died before 1 year post-BMT and 51 patients survived longer than 1 year. Those patients who died before 1 year post-BMT had significantly lower levels of T(4) at 3 weeks, 3 and 6 months than surviving patients. In conclusion, increased levels of serum IL-6 and TNF-alpha were negatively correlated with thyroid hormone concentrations in BMT recipients suggesting the role of these cytokines in euthyroid sick syndrome.