Thyroid hormones and cardiovascular disease

Choroidal vascularity index in thyroid-associated ophthalmopathy: a cross-sectional study

Background

Hemodynamic changes have been observed in patients with Graves’ disease. The aim of our study was to evaluate choroidal vascular change using the choroidal vascularity index (CVI) in patients with thyroid-associated ophthalmopathy (TAO).

Methods

In this cross-sectional observational study, 40 patients affected by TAO were recruited. Forty healthy individuals, matched for age and sex, served as controls. Foveal enhanced-depth imaging optical coherence tomography scans were obtained from all participants. Images were binarized using the ImageJ software and luminal area (LA) and total choroidal area (TCA) were measured. CVI was calculated as the proportion of LA to TCA. The relation between CVI or subfoveal choroidal thickness (SFCT) and clinical activity score, exophthalmometric value, diplopia status, gender, and age was evaluated.

Results

CVI was significantly higher in patients with TAO (P = 0.004). No significant difference was observed in SFCT (P = 0.200) and TCA (P = 0.153) comparing TAO patients and healthy controls. LA was significantly higher in TAO group (P = 0.045). On multiple regression analysis, CVI was associated with TCA (P = 0.043). No association was found between SFCT or CVI and TCA, clinical activity score, exophthalmometric value, Inami value, diplopia status, gender or age (P > 0.05).

Conclusions

This is the first study that has demonstrated an increase in CVI in eyes with TAO compared with healthy controls and has assessed its association with clinical features.

Association of Plasma Connective Tissue Growth Factor Levels with Hyperthyroid Heart Disease

Hyperthyroid heart disease (HHD) is one of the most severe complications of overt hyperthyroidism and increases the risk of mortality in affected patients. Early identification of patients at a higher risk of developing HHD can improve clinical outcomes through active surveillance and management. Connective tissue growth factor (CTGF), a secreted extracellular protein, plays a significant role in cardiac remodeling and dysfunction. We aimed to investigate the association between plasma CTGF level and the risk of HHD in this study. A total of 142 overt hyperthyroid patients without HHD and 99 patients with HHD were included. The plasma CTGF levels were measured using ELISA kits. Routine clinical medical data and echocardiography parameters were recorded for analysis. The plasma CTGF level was significantly higher in patients with HHD than in those without HHD (P=0.002). The plasma CTGF level was positively correlated with free triiodothyronin, tryrotropin receptor antibody, troponin I and lactate dehydrogenase levels and the left atrium diameters, right atrium diameters, and right ventricular end-diastolic diameters (all P<0.05). Logistic regression analysis showed that quartiles 3 and 4 of plasma CTGF levels were significantly associated with the increased risk of HHD (crude OR: 2.529; 95% CI: 1.188-5.387). However, after adjustment for the potentially confounding variables, quartile 4 alone was significantly associated with the higher risk of HHD relative to quartile 1. Hyperthyroid patients with HHD display higher plasma CTGF levels. Furthermore, CTGF is an independent risk factor for HHD. Therefore, the plasma CTGF level may be a potential biomarker for the risk of HHD.

Cardioprotection by post-conditioning with exogenous triiodothyronine in isolated perfused rat hearts and isolated adult rat cardiomyocytes

Ischemic post-conditioning (iPoCo) by coronary re-occlusion/reperfusion during immediate reperfusion after prolonged myocardial ischemia reduces infarct size. Mechanical manipulation of culprit lesions, however, carries the risk of coronary microembolization which may obscure iPoCo's cardioprotection. Pharmacological post-conditioning with exogenous triiodothyronine (T3) could serve as an alternative conditioning strategy. Similar to iPoCo, T3 may activate cardioprotective prosurvival pathways. We aimed to study T3's impact on infarct size and its underlying signal transduction. Hearts were isolated from male Lewis rats (200-380 g), buffer-perfused and subjected to 30 min/120 min global zero-flow ischemia/reperfusion (I/R). In additional hearts, either iPoCo (2 × 30 s/30 s I/R) was performed or T3 (100-500 µg/L) infused at reperfusion. Infarct size was demarcated with triphenyl tetrazolium chloride staining and calculated as percent of ventricular mass. Infarct size was reduced with iPoCo to 16 ± 7% vs. 36 ± 4% with I/R only. The maximum infarct size reduction was observed with 300 µg/L T3 (14 ± 2%). T3 increased the phosphorylation of protein kinase B and mitogen extracellular-regulated-kinase 1/2, both key enzymes of the reperfusion injury salvage kinase (RISK) pathway. Pharmacological RISK blockade (RISK-BL) during reperfusion abrogated T3's cardioprotection (35 ± 10%). Adult ventricular cardiomyocytes were isolated from buffer-perfused rat hearts and exposed to 30 min/5 min hypoxia/reoxygenation (H/R); reoxygenation was initiated without or with T3, respectively, and without or with RISK-BL, respectively. Maximal preservation of viability was observed with 500 µg/L T3 after H/R (27 ± 4% of all cells vs. 5 ± 3% in time-matched controls). Again, RISK-BL abrogated protection (11 ± 3%). Mitochondria were isolated at early reperfusion from buffer-perfused rat hearts without or with iPoCo or 300 µg/L T3, respectively, at reperfusion. T3 improved mitochondrial function (i.e.: increased respiration, adenosine triphosphate production, calcium retention capacity, and decreased reactive oxygen species formation) to a similar extent as iPoCo. T3 at reperfusion reduces infarct size by activation of the RISK pathway. T3's protection is a cardiomyocyte phenomenon and targets mitochondria.

Comprehensive Metabolomics Identified the Prominent Role of Glycerophospholipid Metabolism in Coronary Artery Disease Progression

Background: Coronary stenosis severity determines ischemic symptoms and adverse outcomes. The metabolomic analysis of human fluids can provide an insight into the pathogenesis of complex disease. Thus, this study aims to investigate the metabolomic and lipidomic biomarkers of coronary artery disease (CAD) severity and to develop diagnostic models for distinguishing individuals at an increased risk of atherosclerotic burden and plaque instability.

Methods: Widely targeted metabolomic and lipidomic analyses of plasma in 1,435 CAD patients from three independent centers were performed. These patients were classified as stable coronary artery disease (SCAD), unstable angina (UA), and myocardial infarction (MI). Associations between CAD stages and metabolic conditions were assessed by multivariable-adjusted logistic regression. Furthermore, the least absolute shrinkage and selection operator logistic-based classifiers were used to identify biomarkers and to develop prediagnostic models for discriminating the diverse CAD stages.

Results: On the basis of weighted correlation network analysis, 10 co-clustering metabolite modules significantly (p < 0.05) changed at different CAD stages and showed apparent correlation with CAD severity indicators. Moreover, cross-comparisons within CAD patients characterized that a total of 72 and 88 metabolites/lipid species significantly associated with UA (vs. SCAD) and MI (vs. UA), respectively. The disturbed pathways included glycerophospholipid metabolism, and cysteine and methionine metabolism. Furthermore, models incorporating metabolic and lipidomic profiles with traditional risk factors were constructed. The combined model that incorporated 11 metabolites/lipid species and four traditional risk factors represented better discrimination of UA and MI (C-statistic = 0.823, 95% CI, 0.783–0.863) compared with the model involving risk factors alone (C-statistic = 0.758, 95% CI, 0.712–0.810). The combined model was successfully used in discriminating UA and MI patients (p < 0.001) in a three-center validation cohort.

Conclusion: Differences in metabolic profiles of diverse CAD subtypes provided a new approach for the risk stratification of unstable plaque and the pathogenesis decipherment of CAD progression.

MicroRNAs and thyroid hormone action

MicroRNAs (miRNAs) are small noncoding RNAs that post-transcriptionally repress gene expression by binding generally to the 3'-untranslated regions of their target mRNAs. miRNAs regulate a large fraction of the genome, playing a key role in most physiological and pathological processes. The thyroid hormones (T4 and T3) are major regulators of development, metabolism and cell growth. The thyroid hormones (THs) are synthetized in the thyroid gland and enter the cells through transporter proteins. In the cells, T4 and T3 are metabolized by deiodinase enzymes and bind to nuclear receptors (TRs), which have a higher affinity by T3. TRs act as hormone dependent transcription factors by binding to thyroid hormone response elements (TREs) in the target genes and recruiting transcriptional coregulators. There is increasing evidence that a variety of miRNAs target deiodinases and the receptor, thus regulating TH signaling is different tissues. In turn, the THs have been shown to modulate the expression of specific miRNAs and their mRNA targets in different cell types and organs. In many cases, the existence of TREs in the regulatory regions of these miRNAs has been identified, and the hormone bound receptors transcriptionally regulate expression of these molecules. Changes in the levels of miRNAs have been demonstrated to mediate some of the important actions of the THs in processes such as muscle and heart function, lipid liver metabolism or skin physiology. In addition, miRNA regulation is involved in the effects of TRs on cell proliferation and cancer.

Ignoring a basic pathophysiological mechanism of heart failure progression will not make it go away

A link between heart failure (HF) and low thyroid hormone (TH) function has been known for over a century. Nonetheless, there is a general belief that TH treatment of patients with HF may not be worth the risk. This is largely based on two clinical trials where heart patients were treated with excessive doses of TH analogs, not actual THs. Further complicating the matter is the fact that normalization of THs in noncardiac patients can often be challenging. This issue is not going away as noted by a steady increase in TH-HF citations in recent years. In this article, we discuss what we know and how we may move the field forward.

Thyroid Hormones within the Normal Range and Cardiac Function in the General Population: The EPIPorto Study

BACKGROUND

Hypothyroidism and hyperthyroidism are associated with marked changes in cardiac structure and function. However, the association of thyroid function within the normal range with cardiac structure and function in the general population remains uncertain.

METHODS

Eight hundred thirty-five subjects aged ≥45 years from the EPIPorto cohort (evaluation between 2006 and 2008) were cross-sectionally analyzed. We excluded participants with TSH, free T4 (FT4), or free T3 (FT3) outside of the reference range or with self-reported cardiovascular or thyroid disease. Cardiac structure and function were evaluated by echocardiography. We used linear regression models unadjusted and adjusted for sex and age (model 1), and sex, age, BMI, diabetes, hypertension, and smoking (model 2). Nonlinear associations were assessed using restricted cubic splines.

RESULTS

The mean age was 61.5 years (SD 10.5); 61.1% of the patients were women. In the adjusted model 2, heart rate was positively associated with FT3; diastolic blood pressure was positively associated with TSH; LV end-diastolic and end-systolic volumes were inversely associated with TSH, and ejection fraction was nonlinearly associated with FT3, with higher ejection fractions near the limits of the reference range. Left ventricle (LV) posterior wall thickness was nonlinearly associated with FT4 in the adjusted model 1, with a greater thickness near the limits of the reference range. Regarding diastolic function, no significant associations were observed in adjusted models.

CONCLUSIONS

Thyroid function within the reference range was associated with heart rate, blood pressure, cardiac structure, and function. Increasing thyroid function (lower TSH, higher FT4, or higher FT3) was associated with a higher heart rate, a lower diastolic blood pressure, and larger LV volumes. LV wall thickness and ejection fraction had a U-shaped association with thyroid hormones.

Novel insights into di‑(2‑ethylhexyl)phthalate activation: Implications for the hypothalamus‑pituitary‑thyroid axis

Di (2‑ethylhexyl) phthalate (DEHP), an environmental pollutant, is widely used as a plasticizer and causes serious pollution in the ecological environment. As previously reported, exposure to DEHP may cause thyroid dysfunction of the hypothalamic‑pituitary‑thyroid (HPT) axis. However, the underlying role of DEHP remains to be elucidated. The present study performed intragastrical administration of DEHP (150, 300 and 600 mg/kg) once a day for 90 consecutive days. DEHP‑stimulated oxidative stress increased the thyroid follicular cavity diameter and caused thyrocyte oedema. Furthermore, DEHP exposure altered mRNA and protein levels. Thus, DEHP may perturb TH homeostasis by affecting biosynthesis, biotransformation, bio‑transportation, receptor levels and metabolism through disruption of the HPT axis and activation of the thyroid‑stimulating hormone (TSH)/TSH receptor signaling pathway. These results identified the formerly unappreciated endocrine‑disrupting activities of phthalates and the molecular mechanisms of DEHP‑induced thyrotoxicity.

Thyroid Dysfunction and Dysmetabolic Syndrome: The Need for Enhanced Thyrovigilance Strategies

Thyroid dysfunction (TD) is common in metabolic disorders such as diabetes mellitus (DM), cardiovascular disease (CVD), obesity, dyslipidemia, hyperuricemia, kidney and liver dysfunctions, and polycystic ovary syndrome (PCOS). Subclinical hypothyroidism (SHypo) worsens glycemic control in patients with DM, and these patients, especially those with Type-1DM, have higher prevalence of TD. Both TD and DM increase CVD risk. Even minor alteration in thyroid hormone (TH) levels can alter cardiovascular function. While hyperthyroidism increases systolic blood pressure and leads to high-output heart failure, hypothyroidism increases diastolic blood pressure and leads to low-output heart failure. Chronic subclinical hyperthyroidism (SHyper) and SHypo both increase the risk of hypertension, coronary artery disease (CAD) events, CAD deaths, and total deaths. SHyper alters cardiac morphology and function. SHypo causes dyslipidemia and endothelial dysfunction and increases the risk for weight gain and obesity. Overweight and obese patients often have hyperleptinemia, which increases the secretion of thyroid stimulating hormone (TSH) and induces TD. Dyslipidemia associated with TD can increase serum uric acid levels. Hyperuricemia promotes inflammation and may increase the risk for dyslipidemia, atherosclerosis, and CVD. TD increases the risk for developing chronic kidney disease. In nephrotic syndrome, proteinuria is associated with urinary loss of TH leading to TD. Some correlation between TD and severity of liver disease is also seen. TD and PCOS have common risk factors and pathophysiological abnormalities. Hypothyroidism must be excluded before diagnosing PCOS. Current guidelines do not strongly recommend thyroid screening in the presence of all metabolic disorders. However, pragmatic thyrovigilance is required. Clinicians must stay alert to signs and symptoms of TD, maintain high clinical suspicion, and investigate thoroughly. Drug-induced TD should be considered when TH levels do not match clinical findings or when patients are on medications that can alter thyroid function.

Coexistent subclinical hypothyroidism is associated with an increased risk of new cardiovascular events in rheumatoid arthritis: an explorative study

Objective: Autoimmune thyroid disease often coexists with rheumatoid arthritis (RA) and is associated with elevated cardiovascular (CV) risk. However, studies in RA patients are scarce. Our aim was to investigate whether autoimmune thyroid disease increases the risk of new cardiovascular disease (CVD) in RA.Method: Thyroid-stimulating hormone (TSH) and serum free thyroxine (FT4) were assessed in 323 RA patients participating in an ongoing prospective cohort study designed to assess CV risk factors, morbidity, and mortality. Cox proportional hazard models were used to calculate hazard ratios (HRs) for new CVD and adjusted for age, gender, smoking, prevalent CVD, thyroxine replacement therapy, and RA duration.Results: Of the 323 participants, 65.3% were female, and mean ± sd age was 63 ± 7 years. At baseline, 8.1% were hypothyroid (n = 26, 16 clinical, 10 subclinical), 6.8% hyperthyroid (n = 22, 13 clinical, 9 subclinical), and 85.1% (n = 275) euthyroid. A new CV event developed in 94 patients (29.1%) during follow-up. Compared to euthyroid patients, the HR adjusted for age, gender, and prevalent CVD was 2.83 [95% confidence interval (CI) 1.13-7.09; p = 0.026] for subclinical hypothyroidism. Further adjustment for smoking, thyroxine replacement therapy, and RA duration resulted in an HR of 3.0 (95% CI 1.19-7.54; p = 0.02) for CV events in patients with subclinical hypothyroidism.Conclusion: There was no difference in CVD between RA patients with hypothyroidism and hyperthyroidism versus euthyroid patients. Coexistence of subclinical hypothyroidism with RA is associated with a higher occurrence of new CV events. Treatment trials are needed to determine whether thyroxine supplementation can further improve CV outcome in these patients.

New aspects of endocrine control of atrial fibrillation and possibilities for clinical translation

Hormones are potent endo-, para-, and autocrine endogenous regulators of the function of multiple organs, including the heart. Endocrine dysfunction promotes a number of cardiovascular diseases, including atrial fibrillation (AF). While the heart is a target for endocrine regulation, it is also an active endocrine organ itself, secreting a number of important bioactive hormones that convey significant endocrine effects, but also through para-/autocrine actions, actively participate in cardiac self-regulation. The hormones regulating heart-function work in concert to support myocardial performance. AF is a serious clinical problem associated with increased morbidity and mortality, mainly due to stroke and heart failure. Current therapies for AF remain inadequate. AF is characterized by altered atrial function and structure, including electrical and profibrotic remodelling in the atria and ventricles, which facilitates AF progression and hampers its treatment. Although features of this remodelling are well-established and its mechanisms are partly understood, important pathways pertinent to AF arrhythmogenesis are still unidentified. The discovery of these missing pathways has the potential to lead to therapeutic breakthroughs. Endocrine dysfunction is well-recognized to lead to AF. In this review, we discuss endocrine and cardiocrine signalling systems that directly, or as a consequence of an underlying cardiac pathology, contribute to AF pathogenesis. More specifically, we consider the roles of products from the hypothalamic-pituitary axis, the adrenal glands, adipose tissue, the renin–angiotensin system, atrial cardiomyocytes, and the thyroid gland in controlling atrial electrical and structural properties. The influence of endocrine/paracrine dysfunction on AF risk and mechanisms is evaluated and discussed. We focus on the most recent findings and reflect on the potential of translating them into clinical application.

Lipidomic Perturbations in Cynomolgus Monkeys are Regulated by Thyroid Stimulating Hormone

Thyroid disease affects an estimated 200 million people worldwide, and is commonly associated with increased blood lipid levels. However, the mechanism by which thyroid-stimulating hormone (TSH) affects lipid profiles is not clear. Twenty-four cynomolgus monkeys were treated with a novel exogenous recombinant human TSH (rhTSH) (SNA001) at 9 μg kg⁻¹, 22 μg kg⁻¹, or 54 μg kg⁻¹, and reference rhTSH (Thyrogen^®) at 22 μg kg⁻¹. The primary TSH (SNA001) pharmacokinetic (PK) parameters increased in a dose-dependent manner across the dose range of 9 μg kg⁻¹, 22 μg kg⁻¹, or 54 μg kg⁻¹. Peak triiodothyronine (T3) and thyroxine (T4) levels were reached within 24 h after rhTSH administration, which was delayed by approximately 20 h. In total, 420 lipid species were detected and quantified by ultra-performance liquid chromatography high resolution spectrometry (UPLC-HR-MS)-based lipidomics. Notably, peak levels of lipid accumulation, particularly sphingomyelin (SM) and triglycerides (TG), appeared at 4 and 24 h, which was consistent with the pattern of TSH and T3/T4 levels, respectively. According to weighted correlation network analysis (WGCNA), perturbations of many lipid species were strongly correlated with TSH and T3/T4 levels. TSH and the stimulated T3/T4 levels and lipid profiles following SNA001 administration were comparable to those after administration of the reference rhTSH (Thyrogen^®). The plasma lipidome and changes in lipid levels after rhTSH stimulation were associated with TSH and T3/T4 concentrations. T3/T4 and lipid profiles were delayed after TSH stimulation. Such phenomena require further exploration.

Urinary phthalate metabolite concentrations, oxidative stress and thyroid function biomarkers among patients with thyroid nodules

Prior human studies have explored effects of phthalate exposures on thyroid function, but the underlying biological mechanisms remain poorly unclear. We aimed to explore the associations between phthalate exposures and thyroid function among a potentially susceptible population such as patients with thyroid nodules, and further to assess the mediating role of oxidative stress. We measured eight phthalate metabolites, three oxidative stress biomarkers [8-hydroxy-2-deoxyguanosine (8-OHdG), 8-iso-prostaglandin F_2α (8-isoPGF_2α) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA)] in urine and three thyroid function biomarkers [thyroid-stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4)] in serum among 214 patients with thyroid nodules. Multivariate regression models were applied to assess the associations among urinary phthalate metabolites, oxidative stress and thyroid function biomarkers. The potential mediating role of oxidative stress was explored by mediation analysis. We observed that multiple urinary phthalate metabolites were associated with altered FT4 and increased oxidative stress biomarkers (all FDR-adjusted P ≤ 0.05). Meanwhile, we found that 8-isoPGF_2α was negatively associated with FT3/FT4 among patients with benign thyroid nodules (FDR-adjusted P = 0.08). The mediation analysis indicated that 8-isoPGF_2α mediated the associations of urinary MEHHP and %MEHP with FT3/FT4, with 55.6% and 32.6% proportion of the mediating effects, respectively. Our data suggest that lipid peroxidation may be an intermediate mechanism involved in the effects of certain phthalate exposures on altered thyroid function among patients with benign thyroid nodules.

Treatment of subclinical hypothyroidism: assessing when treatment is likely to be beneficial

Introduction: Subclinical hypothyroidism (SCH) is a common condition diagnosed in up to 16% of the population. SCH is diagnosed when serum TSH is high and circulating thyroid hormones are within the reference range. SCH is considered to be a mild form of thyroid failure by some due to the log-linear relationship between TSH and thyroid hormones. Nevertheless, it is unclear whether the treatment of SCH with thyroid hormones is beneficial, and hence, it is not surprising that expert opinions and recommendations from societies differ in their opinions on how best to manage SCH.Areas covered: This article reviews the currently available evidence pertaining to SCH and provides recommendations as to when treatment of SCH should be considered. An electronic search of PubMed from 1970 to 2019 was performed and systematically reviewed studies assessing the effects of treatment in SCH. The main areas that are considered are the effects of treatment on symptoms and quality of life, and important clinical consequences including psychocognitive outcomes and cardiovascular events.Expert opinion: Treatment of SCH with thyroid hormones is debated and the current literature in this area lacks clarity. We provide an evidence-based recommendation for when treatment of SCH with thyroid hormones should be considered.

Characteristics and Risk Factors of Pulmonary Hypertension in Patients With Hyperthyroidism

OBJECTIVE

This study aimed to comprehensively assess the characteristics and risk factors of hyperthyroidism with pulmonary hypertension (PH).

METHODS

This was a retrospective cross-sectional analysis of 315 consecutive patients with hyperthyroidism admitted to the endocrinology department of Tongji Hospital from February 2016 to December 2017. PH was defined as a pulmonary arterial systolic pressure above 35 mm Hg measured by echocardiography.

RESULTS

Among the 315 patients, 208 were females, the median age was 42 (30-51) years, and the median disease duration was 12 (3-48) months. Thirty-five percent (111/315) of patients were identified with PH. Patients with hyperthyroidism and PH showed significantly higher serum concentrations of free thyroxine (FT4), free triiodothyronine, thyroid receptor antibodies, total bilirubin (TB), direct and indirect bilirubin, lower serum levels of hemoglobin and creatinine, and more severe cardiac load (P < .05 for each) compared with patients without PH. Levels of serum FT4, free triiodothyronine, thyroid receptor antibodies, and thyroid peroxidase antibody were different among groups of patients with different levels of pulmonary arterial systolic pressure (P < .05 for each). Multivariate logistic regression analysis indicated that serum FT4 (odds ratio, 1.02; 95% CI, 1.01-1.04; P = .004) and TB (OR, 1.03; 95% CI, 1.00-1.06; P = .030) were independent risk factors for PH in patients with hyperthyroidism.

CONCLUSION

Elevated serum FT4 and TB levels may be independent risk factors for PH in patients with hyperthyroidism and valuable indicators for the identification and treatment of patients with PH and hyperthyroidism.

Associations Between Thyroid Hormone Levels and Urinary Concentrations of Bisphenol A, F, and S in 6-Year-old Children in Korea

OBJECTIVES

Bisphenol A (BPA) is used in the electrical, mechanical, medical, and food industries. Previous studies have suggested that BPA is an endocrine disruptor. Regulation of BPA has led to increased use of bisphenol F (BPF) and bisphenol S (BPS). However, few studies have investigated the associations of BPF and BPS with thyroid dysfunction in children. Our study investigated the associations of prenatal BPA and early childhood BPA, BPF, and BPS exposure with thyroid function in 6-year-old children.

METHODS

Prenatal BPA concentrations were measured during the second trimester of pregnancy in an established prospective birth cohort. We measured urinary BPA, BPF, and BPS concentrations and thyroid hormone levels (thyroid-stimulating hormone, total T3, and free T4) in 6-year-old children (n=574). We examined the associations between urinary bisphenol concentrations and percentage change of thyroid hormone concentrations using multivariate linear regression. We also compared thyroid hormone levels by dividing the cohort according to BPA, BPF, and BPS concentrations.

RESULTS

The associations between prenatal BPA and total T3 levels were statistically significant in all models, except for girls when using a crude model. The associations between urinary BPA and BPS concentrations and levels of all thyroid hormones were not statistically significant. However, we observed that lower free T4 levels (-1.94%; 95% confidence interval, -3.82 to -0.03) were associated with higher urinary BPF concentrations in girls only.

CONCLUSIONS

Our findings identified significant associations between prenatal BPA exposure and total T3 levels in all children and between BPF exposure and free T4 levels in girls only.

Analyses of the Relation between BPPV and Thyroid Diseases: A Nested Case-Control Study

BACKGROUND

This study investigated relationship between multiple thyroid disorders and benign paroxysmal positional vertigo (BPPV), adjusting for levothyroxine medication.

METHODS

The Korean National Health Insurance Service-Health Screening Cohort data from 2002 to 2015 were used. A total of 19,071 patients with BPPV were matched with 76,284 participants of a control group in a ratio of 1:4 for age, sex, income, and region of residence. The previous histories of thyroid disorders such as goiter, hypothyroidism, thyroiditis, hyperthyroidism, and autoimmune thyroiditis were investigated in both the BPPV and control groups. The odds ratios (ORs) for BPPV in thyroid diseases were calculated using conditional logistic regression analyses.

RESULTS

The histories of goiter (5.5% vs. 4.1%), hypothyroidism (4.7% vs. 3.7%), thyroiditis (2.1% vs. 1.6%), and hyperthyroidism (3.1% vs. 2.5%) were higher in the BPPV group than in the control group (all p < 0.001). Goiter, hypothyroidism, thyroiditis, and hyperthyroidism were associated with BPPV (adjusted OR = 1.28 (95% CI = 1.17-1.39) for goiter, 1.23 (95% CI = 1.10-1.37) for hypothyroidism, 1.13 (95% CI = 1.02-1.26) for hyperthyroidism, each p < 0.05).

CONCLUSIONS

BPPV was associated with thyroid disorders such as goiter, hypothyroidism, thyroiditis, and hyperthyroidism.

Lower levels of triiodothyronine are associated with poor hemodynamic profile and all-cause mortality in heart failure

Background: We aimed to assess the association of triiodothyronine (T3) hormone with invasive hemodynamic parameters and all-cause mortality in heart failure with reduced ejection fraction (HFrEF). Results: About 483 HFrEF patients were enrolled. Patients with the lowest T3 tertile had advanced New York Heart Association (NYHA) classes, had higher uric acid, brain natriuretic peptide. T3 level had a positive correlation with cardiac index (CI) and a negative correlation with pulmonary vascular resistance and pulmonary capillary wedge pressure. Adjusted with NYHA III-IV classes, uric acid, aspartate aminotransferase and CI, T3 level was found to be an independent predictor of all-cause mortality. In Kaplan-Meier analysis, the lowest T3 tertile had the lowest survival function. Conclusion: Free T3 is positively correlated with CI and negatively correlated with pulmonary vascular resistance and pulmonary capillary wedge pressure in patients with HFrEF. Lower levels of T3 seems to be a poor prognostic factor in this particular patient population.

UV-B Filter Octylmethoxycinnamate Alters the Vascular Contractility Patterns in Pregnant Women with Hypothyroidism

Increasing evidence relating the exposure and/or bioaccumulation of endocrine-disrupting compounds (EDCs) with cardiovascular system are arising. Octylmethoxycinnamate (OMC) is the most widely used UV-B filter and as EDC interacts with TH receptors. However, their effects on thyroid diseases during pregnancy remain unknown. The purpose of this work was to assess the short- and long-term effects of OMC on arterial tonus of pregnant women with hypothyroidism. To elucidate this, human umbilical artery (HUA) rings without endothelium were used to explore the vascular effects of OMC by arterial and cellular experiments. The binding energy and the modes of interaction of the OMC into the active center of the TSHR and THRα were analyzed by molecular docking studies. Our results indicated that OMC altered the contractility patterns of HUA contracted with serotonin, histamine and KCl, possibly due to an interference with serotonin and histamine receptors or an involvement of the Ca²⁺ channels. The molecular docking analysis show that OMC compete with T₃ for the binding center of THRα. Taken together, these findings pointed out to alterations in HUA reactivity as result of OMC-exposure, which may be involved in the development and increased risk of cardiovascular diseases.

Relationship between excess iodine, thyroid function, blood pressure, and blood glucose level in adults, pregnant women, and lactating women: A cross-sectional study

High water iodine concentration in drinking water can lead to excessive iodine, which will affect normal thyroid function, blood glucose, and blood pressure, especially among pregnant and lactating women. The aim of the present study was to determine the relationship between iodine, thyroid function, blood pressure, and blood glucose level among adults, and pregnant and lactating women in areas that are iodine-adequate (IA) and iodine-excess (IE) with respect to iodine concentrations in drinking water. A cross-sectional survey was conducted involving 144 pregnant and 237 lactating women in Shanxi Province, and 828 adults in Shandong Province. Water iodine, urinary iodine, thyroid function, blood pressure, and blood glucose were measured. Compared with the IA area, the water iodine concentration (WIC) in the IE area was higher (adults, 325.00 µg/L vs. 71.40 µg/L; pregnant and lactating women, 464.80 µg/L vs. 57.50 µg/L). For adults, and pregnant and lactating women, in the IE area, the urinary iodine concentration (UIC), free thyroxine (FT₄ [except for lactating women]), and systolic blood pressure (only adults 18-40 years of age) were significantly higher, while the blood glucose level and the prevalence of hyperglycemia (except for adults) was lower, and the free triiodothyronine (FT₃), thyroid-stimulating hormone (TSH), thyroglobulin antibody (TgAb), thyroid peroxidase antibody (TPOAb), and hypertension-positive rates of the three populations were not significantly different. For adults, systolic and diastolic pressure were positively correlated with FT₃ and FT₄, respectively, while the blood glucose level were inversely associated with the WIC. For pregnant women, systolic pressure and the WIC, diastolic pressure and FT₄, blood glucose level and FT₃ were all positively correlated, while the blood glucose level was inversely associated with TSH, WIC and UIC. For lactating women, systolic pressure was positively correlated with WIC and UIC, while blood glucose level were inversely associated with WIC and UIC. Pregnant and lactating women in the IE area were at lower risk for an association with hyperglycemia. Collectively, our research showed that long-term exposure to high water iodine is a high-risk factor for abnormal blood pressure and a low-risk factor for abnormal blood glucose level, especially for special populations such as pregnant and lactating women. Moreover, enhanced monitoring of blood pressure and blood glucose level in people with abnormal thyroid function in areas with high water iodine is important.

Effect of Hypovitaminosis D on Lipid Profile in Hypothyroid Patients in Saudi Arabia

Background

Hypothyroidism is believed to be associated with dyslipidemia and is considered a risk factor for the development of atherosclerotic cardiovascular diseases (ASCVD). Vitamin D, due to its steroid hormone action, retains cell function and controls the metabolism of lipids. Therefore, the present study was carried out to show the association of the risk factors of ASCVD and deficiency of thyroid hormones and vitamin D levels since no previous studies have been performed on Saudi patients before. Methodology. A retrospective cohort study was carried out on 400 hypothyroid patients. Medical records of those patients were followed up and were classified as normal and hypothyroid patients according to their thyroid-stimulating hormone levels. TSH, vitamin D, and lipid profiles were determined using the ELISA technique.

Result

Total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels were significantly higher in hypothyroid patients than those in the normal group. We have found a significant correlation between TSH levels and the risk factors of ASCVD (total cholesterol, triglycerides, and LDL-C). Moreover, a significant correlation between vitamin D levels and the risk factors of ASCVD (total cholesterol, triglycerides, and LDL-C) has been found. In addition, there is a correlation between deficiency of Vit D and low-TSH levels (95% CI 1.092-4.05) indicating a higher risk for the development of ASCVD among those patients.

Conclusion

Hypothyroid and vitamin D-deficient patients must be screened regularly at an early stage to predict and also to prevent cardiovascular diseases. Moreover, an adequate supply of vitamin D and TH should be given to those patients to prevent cardiovascular diseases at an early stage.

A Blunted Sympathetic Function and an Enhanced Nitrergic Activity Contribute to Reduce Mesenteric Resistance in Hyperthyroidism

We aimed to determine whether an experimental model of hyperthyroidism could alter the function of sympathetic and nitrergic components of mesenteric innervation. For this purpose, male Wistar rats were divided into (1) control rats (CT) and (2) rats infused with L-Thyroxine (HT). Body weight gain and adipose tissue accumulation were lower in HT rats, while systolic blood pressure and citrate synthase activity in the soleus muscle were increased by HT. In segments from the superior mesenteric artery, the application of an electrical field stimulation (EFS) induced a vasoconstrictor response, which was lower in arteries from HT animals. The alpha-adrenoceptor antagonist phentolamine diminished EFS-induced vasoconstriction to a lower extent in HT arteries, while the purinergic receptor antagonist suramin reduced contractile response to EFS only in segments from CT. In line with this, noradrenaline release, tyrosine hydroxylase expression and activation and dopamine β hydroxylase expression were diminished in HT. The unspecific nitric oxide synthase (NOS) inhibitor L-NAME increased EFS-induced vasoconstriction more markedly in segments from HT rats. NO release was enhanced in HT, probably due to an enhancement in neuronal NOS activity, in which a hyperactivation of both PKC and PI3K-AKT signaling pathways might play a relevant role. In conclusion, perivascular mesenteric innervation might contribute to reduce the vascular resistance observed in hyperthyroidism.

Synergistic Anticancer Activity of N-Hydroxy-7-(2-Naphthylthio) Heptanomide, Sorafenib, and Radiation Therapy in Patient-Derived Anaplastic Thyroid Cancer Models

Anaplastic thyroid cancer (ATC) is an undifferentiated and advanced form of thyroid cancer, accompanied with a high ratio of epigenetic adjustment, which occurs more than genetic mutations. In this study, we aimed to evaluate the synergistic anticancer effect (in vitro and in vivo) of the new combination of N-hydroxy-7-(2-naphthylthio) heptanomide (HNHA) and sorafenib with radiation therapy in pre-clinical models of ATC. The ATC cell lines, YUMC-A1 and YUMC-A2, were isolated from the current patients who were treated with HNHA and sorafenib, either as monotherapy or combination therapy. Synergistic anticancer effect of the combination therapy on the intracellular signaling pathways and cell cycle was assessed via flow cytometry and immunoblot analysis. To examine tumor shrinkage activity in vivo, an ATC cell line-derived mouse xenograft model was used. Results showed that the combination therapy of HNHA and sorafenib with radiation promoted tumor suppression via caspase cleavage and cell cycle arrest in patient-derived ATC. In addition, the combination therapy of HNHA and sorafenib with radiation was more effective against ATC than therapy with HNHA or sorafenib with radiation. Thus, the combination of HNHA and sorafenib with radiation may be used as a novel curative approach for the treatment of ATC.

Predictive Value of Free Triiodothyronine to Free Thyroxine Ratio in Euthyroid Patients With Myocardial Infarction With Nonobstructive Coronary Arteries

BACKGROUND

Thyroid function is closely involved in cardiovascular diseases. The free triiodothyronine (fT3) to free thyroxine (fT4) ratio has been reported as a risk factor for coronary artery disease, but its prognostic value in euthyroid patients with myocardial infarction with nonobstructive coronary arteries (MINOCA) remains unclear.

METHODS

A total of 1162 euthyroid patients with MINOCA were enrolled and divided according to decreased tertiles of fT3/fT4 ratio. The study endpoint was major adverse cardiovascular events (MACE), including all-cause death, nonfatal MI, nonfatal stroke, revascularization, and hospitalization for unstable angina or heart failure. Kaplan-Meier, Cox regression, and receiver-operating characteristic analyses were performed.

RESULTS

Patients with lower fT3/fT4 tertile levels had a significantly higher incidence of MACE (10.0%, 13.9%, 18.2%; p=0.005) over the median follow-up of 41.7 months. The risk of MACE increased with the decreasing fT3/fT4 tertiles even after multivariate adjustment (tertile1 as reference, tertile2: HR 1.58, 95% CI: 1.05-2.39, p=0.030; tertile3: HR 2.06, 95% CI: 1.17-3.11, p=0.006). Lower level of fT3/fT4 ratio remained a robust predictor of MACE in overall (HR 1.64, 95% CI: 1.18-2.29, p=0.003) and in subgroups. When adding fT3/fT4 ratio [area under the curve (AUC) 0.61] into the thrombolysis in myocardial infarction (TIMI) risk score (AUC 0.69), the combined model (AUC 0.74) yielded a significant improvement in discrimination for MACE (ΔAUC 0.05, p=0.023).

CONCLUSIONS

Low level of fT3/fT4 ratio was strongly associated with a poor prognosis in euthyroid patients with MINOCA. Routine assessment of fT3/fT4 ratio may facilitate risk stratification in this specific population.

Low Free Triiodothyronine as a Predictor of Poor Prognosis in Patients With Myocardial Infarction With Non-Obstructive Coronary Arteries

BACKGROUND

Low free triiodothyronine (fT3) level is strongly associated with poor prognosis in various patient populations. However, the role of fT3 in the risk of clinical outcomes in myocardial infarction with non-obstructive coronary arteries (MINOCA) has not been studied. Our study aimed to evaluate the association between low fT3 levels and the clinical outcomes of MINOCA patients.

METHODS

A total of 218 MINOCA patients without a history of thyroid disease were enrolled in the study. Demographic, baseline clinical data, thyroid hormones, and other biochemical parameters were assessed in all patients. According to the fT3 levels, the present study was classified into two groups: the low fT3 group (fT3<3.5 pmol/L) and the normal fT3 group (fT3 3.5-6.5 pmol/L). The endpoint of the study was major adverse cardiac events (MACE).

RESULTS

Fifty-nine patients were in the low fT3 group and 159 patients were in the normal fT3 group. Over the two years of follow-up, 36 MACE have occurred. The occurrence of MACE was higher in the low fT3 group compared with normal fT3 group (25.4% vs 13.2%; P=0.031). Kaplan-Meier survival curves showed a significantly increased risk of MACE in patients with low fT3 (log-rank P=0.027). Multivariable logistic regression analysis stated that high fT3 was independently associated with lower risk of MACE after two years of follow up (OR, 0.623; 95% CI, 0.399- 0.972; P=0.037).

CONCLUSION

Low fT3 levels were significantly associated with increased risk of MACE in patients with MINOCA. This finding suggests that the fT3 levels may serve as a potential biomarker in risk stratification of MINOCA patients.

Association of Maternal Hypothyroidism With Cardiovascular Diseases in the Offspring

BACKGROUND

No previous study has examined the effect of maternal hypothyroidism on a broad spectrum of cardiovascular disease (CVD) endpoints in the offspring.

METHODS

A nationwide population-based cohort study based on the linkage of several Danish nationwide registries was conducted to explore whether maternal hypothyroidism is associated with offspring's CVD. Altogether 1,041,448 singletons born between the 1st of January 1978 and the 31st of December 1998 were investigated from the age of 8 years to the 31st of December 2016. Exposure was maternal diagnosis of hypothyroidism across lifespan and the outcome of interest was a CVD diagnosis in the offspring. Cox regression models were performed to estimate the hazard ratios (HRs) of CVD.

RESULTS

Offspring born to mothers with hypothyroidism had an increased risk of CVD (hazard ratios (HR)=1.23, 95% confidence interval (CI): 1.12-1.35), and of several subcategories of CVD including hypertension, arrhythmia, and acute myocardial infarction in offspring. The magnitude of association was the most pronounced in an exposure occur during pregnancy (HR=1.71, 95% CI: 1.10-2.67), which is consistent across all the subgroup analysis, including sibling analysis.

CONCLUSIONS

Maternal hypothyroidism is associated with an increased risk of CVD in offspring. Thyroid hormone insufficiency during pregnancy may predominantly contribute to the observed associations; however, the effects of a shared genetic background and a time-stable familial environment/lifestyle factors cannot be excluded.

Association of Thyroid Hormone Therapy with Mortality in Subclinical Hypothyroidism: A Systematic Review and Meta-Analysis

CONTEXT

Benefits of thyroid hormone therapy on mortality in adults with subclinical hypothyroidism remain undetermined.

OBJECTIVE

To summarize the impact of thyroid hormone therapy on mortality in adults with subclinical hypothyroidism.

DATA SOURCES

PubMed, Embase, Scopus, Web of Science, and Clinicaltrials.gov from inception until April 25, 2020.

STUDY SELECTION

Studies comparing the effect of thyroid hormone therapy with that of placebo or no therapy in adults with subclinical hypothyroidism on all-cause and/or cardiovascular mortality.

DATA EXTRACTION

Two reviewers independently extracted data and performed quality assessments. Random-effects models for meta-analyses were used.

DATA SYNTHESIS

Five observational studies and 2 randomized controlled trials with 21 055 adults were included. Overall, thyroid hormone therapy was not significantly associated with all-cause (pooled relative risk [RR] = 0.95, 95% confidence interval [CI]: 0.75-1.22, P = .704) or cardiovascular (pooled RR = 0.99, 95% CI: 0.82-1.20, P = .946) mortality. Subgroup analyses revealed that in younger adults (aged <65-70 years), thyroid hormone therapy was significantly associated with a lower all-cause (pooled RR = 0.50, 95% CI: 0.29-0.85, P = .011) and cardiovascular (pooled RR = 0.54, 95% CI: 0.37-0.80, P = .002) mortality. However, no significant association between thyroid hormone therapy and mortality was observed in older adults (aged ≥65-70 years).

CONCLUSIONS

Use of thyroid hormone therapy does not provide protective effects on mortality in older adults with subclinical hypothyroidism. However, thyroid hormone therapy for subclinical hypothyroidism may show benefits on morality in adults aged <65 to 70 years.

Association Between Low T3 Syndrome and Poor Prognosis in Adult Patients With Acute Myocarditis

BACKGROUND

This study aims to investigate the role of free triiodothyronine (fT3) in predicting poor prognosis of adult patients with acute myocarditis.

METHODS

A total of 173 consecutive adult patients with acute myocarditis completed thyroid function evaluations. They were divided into two groups according to fT3 levels: low fT3 group (n = 54, fT3 < 3.54 pmol/liter) and normal fT3 group (n = 119, fT3 ≥ 3.54 pmol/liter). The primary endpoint was major adverse cardiac events (MACE).

RESULTS

During the 3.5 ± 2.8 years follow-up, the rate of MACE was 29.6% versus 3.5% in low fT3 group versus normal fT3 group, respectively (P < 0.0001). Long-term at 8 years MACE-free survival were lower in low fT3 group versus normal fT3 group (52.9% versus 92.3%, log-rank P < 0.0001), respectively. Univariate Cox analysis showed that left ventricular ejection fraction (LVEF) < 50% [hazard ratio (HR) 10.231, 95% confidence interval (CI): 3.418-30.624, P < 0.0001) and low fT3 level (HR 0.360, 95% CI: 0.223-0.582, P < 0.0001) were strongest two predictors of MACE. After adjustment for traditional risk predictors, the prognostic value of fT3 status was still significant (HR 0.540, 95% CI: 0.316-0.922, P = 0.024). Compared with normal fT3 group, those in low fT3 group were at a much higher risk of MACE (HR 5.074, 95% CI: 1.518-16.964, P = 0.008).

CONCLUSIONS

Low T3 syndrome was a strong predictor of poor prognosis in adult patients with acute myocarditis. These findings suggest that fT3 level could serve as a biomarker for risk stratification in acute myocarditis patients.

Levothyroxine Treatment and Cardiovascular Outcomes in Older People With Subclinical Hypothyroidism: Pooled Individual Results of Two Randomised Controlled Trials

BACKGROUND

The cardiovascular effects of treating older adults with subclinical hypothyroidism (SCH) are uncertain. Although concerns have been raised regarding a potential increase in cardiovascular side effects from thyroid hormone replacement, undertreatment may also increase the risk of cardiovascular events, especially for patients with cardiovascular disease (CVD).

OBJECTIVE

To determine the effects of levothyroxine treatment on cardiovascular outcomes in older adults with SCH.

METHODS

Combined data of two parallel randomised double-blind placebo-controlled trials TRUST (Thyroid hormone Replacement for Untreated older adults with Subclinical hypothyroidism - a randomised placebo controlled Trial) and IEMO80+ (the Institute for Evidence-Based Medicine in Old Age 80-plus thyroid trial) were analysed as one-stage individual participant data. Participants aged ≥65 years for TRUST (n=737) and ≥80 years for IEMO80+ (n=105) with SCH, defined by elevated TSH with fT4 within the reference range, were included. Participants were randomly assigned to receive placebo or levothyroxine, with titration of the dose until TSH level was within the reference range. Cardiovascular events and cardiovascular side effects of overtreatment (new-onset atrial fibrillation and heart failure) were investigated, including stratified analyses according to CVD history and age.

RESULTS

The median [IQR] age was 75.0 [69.7-81.1] years, and 448 participants (53.2%) were women. The mean TSH was 6.38± SD 5.7 mIU/L at baseline and decreased at 1 year to 5.66 ± 3.3 mIU/L in the placebo group, compared with 3.66 ± 2.1 mIU/L in the levothyroxine group (p<0.001), at a median dose of 50 μg. Levothyroxine did not significantly change the risk of any of the prespecified cardiovascular outcomes, including cardiovascular events (HR 0.74 [0.41-1.25]), atrial fibrillation (HR 0.69 [0.32-1.52]), or heart failure (0.41 [0.13-1.35]), or all-cause mortality (HR 1.28 [0.54-3.03]), irrespective of history of CVD and age.

CONCLUSION

Treatment with levothyroxine did not significantly change the risk of cardiovascular outcomes in older adults with subclinical hypothyroidism, irrespective of a history of cardiovascular disease and age.

CLINICAL TRIAL REGISTRATION

[ClinicalTrials.gov], identifier [NCT01660126] (TRUST); Netherlands Trial Register: NTR3851 (IEMO80+).

Identification of Featured Metabolism-Related Genes in Patients with Acute Myocardial Infarction

Objective

A growing body of emerging evidence indicates that metabolic processes play a pivotal role in the biological processes underlying acute myocardial infarction (AMI). The aim of the current study was to identify featured metabolism-related genes in patients with AMI using a support vector machine (SVM) and to further explore the value of these genes in the diagnosis of AMI.

Methods

Gene microarray expression data related to AMI were downloaded from the GSE66360 dataset in the Gene Expression Omnibus (GEO) database. This data set consisted of 50 AMI samples and 49 normal controls that were randomly classified into a discovery cohort (21 AMI samples and 22 normal controls) and a validation cohort (28 AMI and 28 normal controls). We applied a machine learning method that combined SVM with recursive feature elimination (RFE) to discriminate AMI patients from normal controls. Based on this, an SVM classifier was constructed. Receiver operating characteristic (ROC) analysis was used to investigate the predictive value for the early diagnosis of AMI in the two cohorts and was then further verified in an independent external cohort.

Results

Three metabolism-related genes were identified based on SVM-RFE (AKR1C3, GLUL, and PDE4B). The SVM classifier based on the three genes allowed for excellent discrimination between AMI and healthy samples in both the discovery cohort (AUC = 0.989) and the validation cohort (AUC = 0.964), and this was further confirmed in the GSE68060 dataset (AUC = 0.839). Additionally, the SVM classifier allowed for perfect discrimination between recurrent AMI events and nonrecurrent events in the GSE68060 cohort (AUC = 0.992). GO and KEGG pathway enrichment analysis of the identified featured genes revealed significant enrichment of specific metabolic pathways.

Conclusion

The identified metabolism-related genes may play important roles in the development of AMI and may represent diagnostic and therapeutic biomarkers of AMI.

The Association of Overt and Subclinical Hyperthyroidism with the Risk of Cardiovascular Events and Cardiovascular Mortality: Meta-Analysis and Systematic Review of Cohort Studies

BACKGROUND

Whether hyperthyroidism is an independent risk factor for cardiovascular events remains controversial. We aimed to evaluate the association of overt and subclinical hyperthyroidism with the risk of ischemic heart disease (IHD), stroke, heart failure, and cardiovascular mortality.

METHODS

Studies regarding the association between hyperthyroidism and cardiovascular events were searched on PubMed and Embase databases. The cardiovascular disease (CVD) risk was classified as high and low, based on pre-existing diseases, including history of coronary, cerebral, or peripheral artery disease; heart failure; atrial fibrillation; diabetes mellitus; or chronic kidney disease.

RESULTS

Thirty-seven cohort studies were included in this meta-analysis. The pooled hazard ratio for subjects with overt hyperthyroidism compared with the control group was 1.11 (95% confidence interval [CI], 1.03 to 1.19) for IHD, 1.35 (95% CI, 1.03 to 1.75) for stroke, and 1.20 (95% CI, 1.00 to 1.46) for cardiovascular mortality. For subjects with subclinical hyperthyroidism, the pooled hazard ratio was 1.24 (95% CI, 1.07 to 1.45) for IHD, when compared with the control group. Subgroup analysis by CVD risk showed that the risk of stroke in overt hyperthyroidism was increased in the low CVD risk group; however, these association was not observed in the high CVD risk group. Similarly, the risk of IHD in subjects with subclinical hyperthyroidism was significantly increased in the low CVD risk group.

CONCLUSION

Overt hyperthyroidism is associated with increased risk of IHD, stroke, and cardiovascular mortality, and subclinical hyperthyroidism is associated with increased risk of IHD. These associations were particularly observed in the low risk CVD group without underlying CVD.

Associations of Thyroid Hormones and Resting Heart Rate in Patients Referred to Coronary Angiography

Resting heart rate (RHR) is associated with increased risk of cardiovascular morbidity and mortality. Thyroid hormones exert several effects on the cardiovascular system, but the relation between thyroid function and RHR remains to be further established. We evaluated whether measures of thyroid hormone status are associated with RHR in patients referred to coronary angiography. Thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxin (FT4), and RHR were determined in 2795 participants of the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study. Median (25th to 75th percentile) serum concentrations were 1.25 (0.76-1.92) mU/l for TSH, 4.8 (4.2-5.3) pmol/l for FT3 and 17.1 (15.4-19.0) pmol/l for FT4, and mean (±standard deviation) RHR was 68.8 (±11.7) beats/min. Comparing the highest versus the lowest quartile, RHR (beats/min) was significantly higher in the fourth FT4 quartile [3.48, 95% confidence interval (CI): 2.23-4.73; p <0.001] and in the fourth FT3 quartile (2.30, 95% CI: 1.06-3.55; p <0.001), but there was no significant difference for TSH quartiles. In multiple linear regression analyses adjusting for various potential confounders, FT3 and FT4 were significant predictors of RHR (p <0.001 for both). In subgroups restricted to TSH, FT3, and FT4 values within the reference range, both FT3 and FT4 remained significant predictors of RHR (p <0.001 for all). In conclusion, in patients referred to coronary angiography, FT3 and FT4 but not TSH were positively associated with RHR. The relationship between free thyroid hormones and RHR warrants further investigations regarding its diagnostic and therapeutic implications.

Changes in thyroid function in patients with liver failure and their clinical significance: A clinical study of non-thyroidal illness syndrome in patients with liver failure

BACKGROUND

Non-thyroidal illness syndrome (NTIS) develops in a large proportion of critically ill patients and is associated with high risk for death. We aimed to investigate the correlation between NTIS and liver failure, and the short-term mortality of patients with these conditions.

METHODS

The clinical data of 87 patients with liver failure were collected retrospectively, 73 of them were randomly selected for an observational study and to establish prognostic models, and 14 for model validation. Another 73 sex- and age-matched patients with mild chronic hepatitis were randomly selected as a control group. Serum free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were measured. The clinical characteristics of patients with liver failure and NTIS were analyzed. The follow-up of patients lasted for 3 months. Additionally, the values for predicting short-term mortality of model for end-stage liver disease (MELD), Child-Turcotte-Pugh (CTP), chronic liver failure-sequential organ failure assessment (CLIF-SOFA) scores, FT3-MELD model, and FT3 were evaluated.

RESULTS

The observation group had significantly lower FT3 (2.79 ± 0.71 vs. 4.43 ± 0.75 pmol/L, P < 0.001) and TSH [0.618 (0.186-1.185) vs. 1.800 (1.570-2.590) mIU/L, P < 0.001], and higher FT4 (19.51 ± 6.26 vs. 14.47 ± 2.19 pmol/L, P <0.001) than the control group. NTIS was diagnosed in 49 of the patients with liver failure (67.12%). In the observation group, patients with NTIS had a higher mortality rate than those without (63.27% vs. 25.00%, P = 0.002). Across the whole cohort, the 3-month mortality was 50.68%. The international normalized ratios (INR) were 2.40 ± 1.41 in survivors and 3.53 ± 1.81 in deaths (P = 0.004), the creatinine (Cr) concentrations were 73.27 ± 36.94 µmol/L and 117.08 ± 87.98 µmol/L (P = 0.008), the FT3 concentrations were 3.13 ± 0.59 pmol/L and 2.47 ± 0.68 pmol/L (P < 0.001), the MELD scores were 22.19 ± 6.64 and 29.57 ± 7.99 (P < 0.001), the CTP scores were 10.67 ± 1.53 and 11.78 ± 1.25 (P = 0.001), and the CLIF-SOFA scores were 8.42 ± 1.68 and 10.16 ± 2.03 (P < 0.001), respectively. FT3 was negatively correlated with MELD score (r = -0.430, P < 0.001). An FT3-MELD model was established by subjecting FT3 concentration and MELD score to logistic regression analysis using the following formula: Logit(P) = -1.337 × FT3+0.114 × MELD+0.880. The area under the receiver operating characteristic (ROC) curve was 0.827 and the optimal cut-off value was 0.4523. The corresponding sensitivity and specificity were 67.6% and 91.7%. The areas under the ROC curve for FT3 concentration, MELD score, CTP score, and CLIF-SOFA score were 0.809, 0.779, 0.699, and 0.737, respectively.

CONCLUSIONS

Patients with liver failure often develop NTIS. FT3-MELD score perform better than CTP and CLIF-SOFA scores in predicting mortality in patients with liver failure. Thus, the FT3-MELD model could be of great value for the evaluation of the short-term mortality of such patients.

Epigenetics and Heart Failure

Epigenetics refers to changes in phenotypes without changes in genotypes. These changes take place in a number of ways, including via genomic DNA methylation, DNA interacting proteins, and microRNAs. The epigenome is the second dimension of the genome and it contains key information that is specific to every type of cell. Epigenetics is essential for many fundamental processes in biology, but its importance in the development and progression of heart failure, which is one of the major causes of morbidity and mortality worldwide, remains unclear. Our understanding of the underlying molecular mechanisms is incomplete. While epigenetics is one of the most innovative research areas in modern biology and medicine, compounds that directly target the epigenome, such as epidrugs, have not been well translated into therapies. This paper focuses on epigenetics in terms of genomic DNA methylation, such as 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) modifications. These appear to be more dynamic than previously anticipated and may underlie a wide variety of conditions, including heart failure. We also outline possible new strategies for the development of novel therapies.

Association between sub-clinical hypothyroidism and heart failure with preserved ejection fraction

Supplemental Digital Content is available in the text

Subclinical Thyroid Dysfunction and the Risk of Cardiovascular Disease

The prevalence of subclinical hypothyroidism (SH) is 3-10%. The prevalence of subclinical hyperthyroidism (SHr) is 0.7-9.7%. Thyroid hormones affect cardiac electrophysiology, contractility, and vasculature. SH is associated with an increased risk of coronary heart disease (CHD), especially in subjects under 65. SHr seems to be associated with a slightly increased risk of CHD and an increase in CHD-related mortality. Both SH and SHr carry an increased risk of developing heart failure (HF), especially in those under 65. Both SH and SHr are associated with worse prognoses in patients with existing HF. SH is probably not associated with atrial fibrillation (AF). SHr, low normal thyroid-stimulating hormone (TSH) and high normal free thyroxine (FT4) are all associated with the increased risk of AF. An association between endothelial dysfunction and SH seems to exist. Data regarding the influence of SHr on the peripheral vascular system are conflicting. SH is a risk factor for stroke in subjects under 65. SHr does not increase the risk of stroke. Both SH and SHr have an unfavourable effect on cardiovascular disease (CVD) and all-cause mortality. There is a U-shaped curve of mortality in relation to TSH concentrations. A major factor that modifies the relation between subclinical thyroid disease (SCTD) and mortality is age. SH increases blood pressure (BP). SHr has no significant effect on BP. Lipids are increased in patients with SH. In SHr, high-density lipoprotein cholesterol and lipoprotein( a) are increased. SCTD should be treated when TSH is over 10 mU/l or under 0.1 mU/l. Treatment indications are less clear when TSH is between normal limits and 0.1 or 10 mU/L. The current state of knowledge supports the understanding of SCTD's role as a risk factor for CVD development. Age is a significant confounding factor, probably due to age-associated changes in the TSH reference levels.

Thyroid dysfunction and cardiovascular events in patients with chronic kidney disease: A protocol of systematic review and meta-analysis

BACKGROUND

Cardiovascular disease is the main cause of death in patients with chronic kidney disease (CKD). Studies have found that hypothyroidism can significantly increase cardiovascular risk. Meanwhile, hypothyroidism is a common complication of CKD, but the correlation between hypothyroidism and cardiovascular risk in CKD patients has not been verified and paid enough attention. We therefore plan to conduct a systematic review and meta-analysis to explore whether hypothyroidism was independently predictive for the cardiovascular risk in patients with CKD.

METHODS

We will search in PubMed, Embase Database, Web of Science, China National Knowledge Infrastructure (CNKI), China Biology Medicine Database (CBM), and Wanfang Database, and include the cross-sectional studies, case--control studies, and cohort studies that explore the association between hypothyroidism and cardiovascular risk in CKD patients. According to the eligibility criteria, two researchers will independently screen the retrieved literature, evaluate the methodological quality, and extract data. We will combine the extracted data based on STATA and TSA software.

RESULTS

This systematic review will assess the association between hypothyroidism and cardiovascular risk in CKD patients based on the incidence of cardiovascular events in CKD people with hypothyroidism.

CONCLUSIONS

This study will provide more evidence for the correlation between hypothyroidism and cardiovascular risk in CKD patients, which will contribute to the management and clinical practice of CKD population.

ETHICS AND DISSEMINATION

This protocol is based on available literatures so that the ethical approval and informed consent are not applicable. The results of this study will be published in a peer-reviewed journals or relevant conferences.

PROTOCOL REGISTRATION NUMBER

INPLASY2020100022.

Epidemiology of metabolic syndrome and its components in Chinese patients with a range of thyroid-stimulating hormone concentrations

Objective

To investigate the relationship between thyroid stimulating hormone (TSH) concentration and the risks of developing metabolic syndrome and its components.

Methods

A total of 10,140 residents of the Yunyan district of Guiyang (Guizhou, China) who were ≥40 years old were selected by cluster random sampling between May and August 2011, of whom 5692 were eligible. TSH concentration and indices of metabolic syndrome were documented at baseline and 3 years later. Participants were allocated to a euthyroid (TSH 0.55–4.78 mIU/L) or high TSH concentration (TSH >4.78 mIU/L) group. Patients with overt hypothyroidism or were undergoing treatment for hypothyroidism were excluded.

Results

The crude and adjusted prevalences of metabolic syndrome were 39.9% and 33.9% in the euthyroid group and 44.3% and 37.5% in the high TSH group, respectively. Binary logistic regression analysis revealed a positive correlation between a high TSH concentration at baseline and the cumulative incidence of metabolic syndrome during follow up.

Conclusions

High TSH is associated with a higher risk of developing metabolic syndrome or one of its components; therefore, people with a high TSH concentration should be screened regularly to permit the early identification of metabolic syndrome and followed up thoroughly.

Hypothyroidism impairs the host immune response during the acute phase of Chagas disease

Diseases associated with thyroid hypofunction have been the subject of studies in infectious models, since several authors have demonstrated a pivotal role of iodinated hormones (thyroxine and triiodothyronine) in the modulation of immune effector responses. Using a model of hypothyroidism induced by anti-thyroid drug, we investigated the influence of hypothyroidism in the course of acute Trypanosoma cruzi infection. For this, male Hannover Wistar rats were challenged with methimazole for 21 days (0.02% in drinking water), and water for control counterparts. After confirmation of the hypothyroidism, rats were intraperitoneally challenged with 1x10⁵ blood trypomastigotes of the Y strain of T. cruzi. Our findings suggest that hypothyroidism impairs animal weight gain, but does not affect the health of essential organs. Interestingly, infected hypothyroid animals had a significant increase in thymic cell death, with consequent drop in lymphocyte frequency in whole blood (evaluated on the 11th day of infection). Analyzing the percentage of immune cells in the spleen, we found a strong influence of hypothyroidism as a negative regulator of B cells, and antigenic ability of macrophages (RT1b expression) in the course of the experimental chagasic infection. Enhanced serum IL-17A concentration was induced by T. cruzi infection, but hypothyroidism impaired the production of this mediator as seen in infected hypothyroid animals. Taken together, our work suggests for the first time that hypothyroidism may adversely interfere with the modulation of effective immunity in the early phase of Chagas' disease.

High prevalence of non-thyroidal illness syndrome in patients at long-term care facilities

PURPOSE

Patients in acute care hospitals are often transferred to long-term care (LTC) when there is an expectation for a lengthy recovery. Prolonged non-thyroidal illness syndrome (NTIS) creates a state of hypothyroidism. We aimed to investigate the prevalence of NTIS in patients at LTC facilities.

METHODS

A cross-sectional study at University Hospitals and Rehabilitation and Skilled Nursing facility was performed. Four groups: control (n:33), intensive care unit (ICU) (n:34), long-term care hospital (LTCH) (n:50), and long-term care on chronic ventilatory support (LTCVS) (n:30). Serum levels of TSH, free T4 (FT4), free T3 (FT3), and interleukin 6 (IL6) measured at admission day in controls, within 48 h of admission in the intensive care group, between days 31 and 120 in the LTC hospital group and days 31 and 6 years in the LTC on chronic ventilatory support group.

RESULTS

Serum FT3 levels were lower in groups intensive care unit ICU, LTCH, and LTCVS than control. Low serum FT3 levels were observed in 80% ICU, 54% LTCH, 37% LTCVS, and 6% control patients. Low serum FT4 levels were observed in 32% ICU, 16% LTCH, and 20% LTCVS patients. Both low serum FT4 and FT3 levels were observed in 32% ICU, 16% LTCH, and 13% LTCVS patients. Serum IL6 and FT3 levels showed a negative correlation.

CONCLUSIONS

NTIS is highly prevalent in patients in LTC, creating a state of persistent hypothyroidism. The effects of thyroid hormone replacement in patients at LTC with non-thyroidal illness deserve further investigation.

Altered thyroid hormone profile in patients with Alzheimer's disease

BACKGROUND

Epidemiological studies have linked higher levels of thyroid hormones (THs) to increased risk of Alzheimer's disease (AD), whereas in advanced AD, THs have been unchanged or even decreased. In early AD dementia, little is known whether THs are related to AD neuropathology or brain morphology.

METHODS

This was a cross-sectional study of 36 euthyroid AD patients and 34 healthy controls recruited at a single memory clinic. Levels of THs were measured in serum and cerebrospinal fluid (CSF). In addition, we determined AD biomarkers (amyloid-β_1-42, total tau and phosphorylated tau) in CSF and hippocampal and amygdalar volumes using magnetic resonance imaging.

RESULTS

Serum free thyroxine (FT4) levels were elevated, whereas serum free triiodothyronine (FT3)/FT4 and total T3 (TT3)/total T4 (TT4) ratios were decreased, in AD patients compared to controls. In addition, serum TT4 was marginally higher in AD (p = 0.05 vs. the controls). Other TH levels in serum as well as CSF concentrations of THs were similar in both groups, and there were no correlations between THs and CSF AD biomarkers. However, serum FT3 correlated positively with left amygdalar volume in AD patients and serum TT3 correlated positively with left and right hippocampal volume in controls.

CONCLUSIONS

Thyroid hormones were moderately altered in mild AD dementia with increased serum FT4, and in addition, the reduced T3/T4 ratios may suggest decreased peripheral conversion of T4 to T3. Furthermore, serum T3 levels were related to brain structures involved in AD development.

The Two Faces of Janus: Why Thyrotropin as a Cardiovascular Risk Factor May Be an Ambiguous Target

Elevated concentrations of free thyroid hormones are established cardiovascular risk factors, but the association of thyrotropin (TSH) levels to hard endpoints is less clear. This may, at least in part, ensue from the fact that TSH secretion depends not only on the supply with thyroid hormones but on multiple confounders including genetic traits, medication and allostatic load. Especially psychosocial stress is a still underappreciated factor that is able to adjust the set point of thyroid function. In order to improve our understanding of thyroid allostasis, we undertook a systematic meta-analysis of published studies on thyroid function in post-traumatic stress disorder (PTSD). Studies were identified via MEDLINE/PubMed search and available references, and eligible were reports that included TSH or free thyroid hormone measurements in subjects with and without PTSD. Additionally, we re-analyzed data from the NHANES 2007/2008 cohort for a potential correlation of allostatic load and thyroid homeostasis. The available evidence from 13 included studies and 3386 euthyroid subjects supports a strong association of both PTSD and allostatic load to markers of thyroid function. Therefore, psychosocial stress may contribute to cardiovascular risk via an increased set point of thyroid homeostasis, so that TSH concentrations may be increased for reasons other than subclinical hypothyroidism. This provides a strong perspective for a previously understudied psychoendocrine axis, and future studies should address this connection by incorporating indices of allostatic load, peripheral thyroid hormones and calculated parameters of thyroid homeostasis.

New Insights into Mechanisms of Endocrine-Disrupting Chemicals in Thyroid Diseases: The Epigenetic Way

In recent years, the presence in the environment of chemical compounds with thyroid-disrupting effects is progressively increased. This phenomenon has risen concern for human health as the preservation of thyroid system homeostasis is essential for fetal development and for maintaining psychological and physiological wellbeing. An increasing number of studies explored the role of different classes of toxicants in the occurrence and severity of thyroid diseases, but large epidemiological studies are limited and only a few animal or in vitro studies have attempted to identify the mechanisms of chemical action. Recently, epigenetic changes such as alteration of methylation status or modification of non-coding RNAs have been suggested as correlated to possible deleterious effects leading to different thyroid disorders in susceptible individuals. This review aims to analyze the epigenetic alterations putatively induced by chemical exposures and involved in the onset of frequent thyroid diseases such as thyroid cancer, autoimmune thyroiditis and disruption of fetal thyroid homeostasis.

Massive pericardial effusion and cardiac tamponade revealed undiagnosed Turner syndrome: a case report

Background

Patients with Turner syndrome (TS) are prone to autoimmune disorders. Although most patients with TS are diagnosed at younger ages, delayed diagnosis is not rare.

Case presentation

A 31-year-old woman was presented with facial edema, chest tightness and dyspnea. She had primary amenorrhea. Physical examination revealed short stature, dry skin and coarse hair. Periorbital edema with puffy eyelids were also noticed with mild goiter. Bilateral cardiac enlargement, distant heart sounds and pulsus paradoxus, in combination with hepatomegaly and jugular venous distention were observed. Her hircus and pubic hair was absent. The development of her breast was at 1st tanner period and gynecological examination revealed infantile vulva. Echocardiography suggested massive pericardial effusion. She was diagnosed with cardiac tamponade based on low systolic pressure, decreased pulse pressure and pulsus paradoxus. Pericardiocentesis was performed. Thyroid function test and thyroid ultrasound indicated Hashimoto’s thyroiditis and severe hypothyroidism. Sex hormone test revealed hypergonadotropin hypogonadism. Further karyotyping revealed a karyotype of 45, X [21]/46, X, i(X) (q10) [29] and she was diagnosed with mosaic + variant type of TS. L-T4 supplement, estrogen therapy, and antiosteoporosis treatment was initiated. Euthyroidism and complete resolution of the pericardial effusion was obtained within 2 months.

Conclusion

Hypothyroidism should be considered in the patients with pericardial effusion. The association between autoimmune thyroid diseases and TS should be kept in mind. Both congenital and acquired cardiovascular diseases should be screened in patients with TS.

Evaluation of retinal and choroidal variations in thyroid-associated ophthalmopathy using optical coherence tomography angiography

Background

To investigate the difference in retinal nerve fiber layer (RNFL) thickness, choroidal thickness (CT) and superficial retinal vessels between thyroid-associated ophthalmopathy (TAO) patients and healthy controls. To identify the potential influencing factors for these parameters and evaluate their diagnostic abilities in TAO.

Methods

Twenty active TAO patients, 33 inactive TAO patients and 29 healthy participants were enrolled. TAO patients were divided according to the clinical activity score (CAS). RNFL thickness and CT were measured by HD-OCT, while foveal avascular zone (FAZ), vascular density and perfusion density were measured by optical coherence tomography angiography (OCTA). SPSS software was used for statistical analysis.

Results

Active TAO patients had thinner RNFL thickness than the other two groups (P < 0.001, P < 0.001). Both active and inactive TAO patients had significantly higher CT in the macular region (all P < 0.05). The FAZ area in the active TAO group was significantly larger than the other two groups (P = 0.045, P = 0.001). The inactive TAO group had significantly higher vascular density than the other two groups (all P < 0.05). With regard to the perfusion density, significant differences were observed in the temporal and inferior areas (P = 0.045, P = 0.001), as well as the average values (P = 0.032). The FAZ area was positively correlated with intraocular pressure (r = 0.274, P = 0.013), while it was negatively correlated with axial length (r = − 0.344, P = 0.002). The vascular density and perfusion density were not significantly correlated with different clinical variables (all P > 0.05). The AUC analysis indicated these parameters also exhibited a significant discriminatory power in TAO diagnosis.

Conclusions

TAO patients had significant variations in RNFL thickness, choroidal thickness, FAZ area and superficial retinal vessels. These parameters appeared to be potential adjuncts in the evaluation of TAO patients.