Thyroid hormones and cardiovascular disease

Inflammation and endothelial dysfunction in pediatric migraine patients

BACKGROUND

Inflammation and endothelial dysfunction are the suggested underlying mechanisms in migraine. Pentraxins, C-reactive protein, erythrocyte sedimentation rate, neutrophil to lymphocyte ratio, platelet to lymphocyte ratio are good indicators of inflammation. Alterations in insulin levels and insulin sensitivity may trigger endothelial dysfunction. This study evaluates the association between migraine and serum biomarkers of inflammation and endothelial dysfunction in children.

METHODS

Children with migraine and healthy subjects were recruited. Serum samples were obtained in an attack-free period. We collected data on serum levels of complete blood cell count, C-reactive protein, erythrocyte sedimentation rate, pentraxin-3, and data from biochemical investigations. We compared these with clinical data such as age, sex, disease duration, attack frequency, attack duration, analgesic use, family history, and Pediatric Migraine Disability Assessment Questionnaire scores.

RESULTS

We assessed samples from 32 children (11 boys, 21 girls) with migraine and 19 healthy controls (8 boys, 11 girls). We found significantly higher pentraxin-3, insulin, and insulin resistance in patients with migraine (P = 0.001, P = 0.032, and P = 0.008, respectively). A positive directional correlation is found between pentraxin-3 and Pediatric Migraine Disability Assessment Questionnaire scores. The best cut-off values for pentraxin-3 is determined between 12.75 pg/mL to 15 pg/mL in migraineurs.

CONCLUSIONS

In conclusion increased pentraxin-3 levels support the suggestions that inflammation plays a role in pediatric migraine. The vascular endothelial dysfunction is observed by a rise in insulin and insulin resistance levels. Our findings support the idea that ongoing inflammation and vascular endothelial dysfunction between attacks may play a role in migraine pathogenesis in children.

The Thyroid Condition and Residual Clinical Signs in 31 Existing Endemic Neurological Cretins After 42 Years of Iodine Supplementation in China

BACKGROUD

Endemic cretinism is the most severe manifestation among the iodine deficiency-related disorders. The clinical status of the cretins may be modified subsequently by the duration and severity of the disease. We aimed to reassess the clinical status and thyroid function of 31 surviving "neurological cretins" after 42 years of iodine supplementation in a historically severely iodine deficiency area of China.

METHODS

It was a cross-sectional study in design and we investigated all 31 surviving neurological cretins and 85 controls. A detailed neurological examination was conducted on each patients. All the participants were given a questionnaire and underwent B-mode ultrasonography of the thyroid. The serum levels of thyroid hormones, thyroid antibodies, serum iodine concentration (SIC) and urine iodine concentration (UIC) were measured.

RESULTS

The neurological cretins had shorter stature than that of the control. Neurological damage is still present in patients with cretinism. The prevalence of subclinical hypothyroidism and thyroid nodule in the cretins was significantly higher (χ² =4.766, P=0.029 and χ² =17.077, P<0.0001, respectively) compared with the control. After adjusting for confounding factors, endemic neurocretinism was found to be an independent risk factor for subclinical hypothyroidism (OR=4.412; 95% CI: 1.358-14.334; P=0.014) and thyroid nodule (OR=6.433; 95% CI: 2.323-17.816; P<0.0001).

CONCLUSIONS

Iodine supplementation after birth does not reverse the neurological damage that results from maternal/foetal hypothyroidism in utero and is subsequently manifested as neurological cretinism. There is a cross-sectional association between endemic neurocretinism and subclinical hypothyroidism and thyroid nodule.

Graves' disease, its treatments, and the risk of atrial fibrillation: A Korean population-based study

BACKGROUND

Atrial fibrillation (AF) is occasionally diagnosed in individuals with Graves' disease. Definite treatments, including radioactive iodine therapy (RAIT) or surgery might lower the risk of AF in the literature. However, no studies have compared the effects of anti-thyroid drugs (ATDs), RAIT, and surgery on the risk of AF.

METHODS

This retrospective cohort study included 94,060 newly diagnosed Graves' disease patients and 470,300 controls from the Korean National Health Insurance database. The incidence of AF was evaluated in patients and controls. Patients were categorized based on treatment method into ATD (95.6%), RAIT (3.5%), and surgery (0.9%) groups. In the ATD group, the dose and duration of ATDs were calculated for each patient. In the RAIT and surgery groups, remission was defined as levothyroxine prescription.

RESULTS

Graves' disease patients had a 2.2-fold higher risk of developing AF than controls. Regardless of demographic factors, the patient group had a consistently higher risk of AF than controls, with the highest risk of AF (HR, 5.49) in the younger patient group. The surgery group had a similar risk of AF compared with controls, whereas the ATD (HR, 2.23) and RAIT (HR, 2.00) groups had increased risks of AF, even in patients reaching hypothyroid status after RAIT. Patients with higher dose or longer treatment duration of ATDs were at greater risk of AF.

CONCLUSION

We observed differing risks of AF according to methods of treatment for Graves' disease, and that definite treatment can be an option for subjects needing sustained medical treatment considering the risk of AF.

Disruption by stealth - Interference of endocrine disrupting chemicals on hormonal crosstalk with thyroid axis function in humans and other animals

Thyroid hormones (THs) are important regulators of growth, development, and homeostasis of all vertebrates. There are many environmental contaminants that are known to disrupt TH action, yet their mechanisms are only partially understood. While the effects of Endocrine Disrupting Chemicals (EDCs) are mostly studied as "hormone system silos", the present critical review highlights the complexity of EDCs interfering with TH function through their interactions with other hormonal axes involved in reproduction, stress, and energy metabolism. The impact of EDCs on components that are shared between hormone signaling pathways or intersect between pathways can thus extend beyond the molecular ramifications to cellular, physiological, behavioral, and whole-body consequences for exposed organisms. The comparatively more extensive studies conducted in mammalian models provides encouraging support for expanded investigation and highlight the paucity of data generated in other non-mammalian vertebrate classes. As greater genomics-based resources become available across vertebrate classes, better identification and delineation of EDC effects, modes of action, and identification of effective biomarkers suitable for HPT disruption is possible. EDC-derived effects are likely to cascade into a plurality of physiological effects far more complex than the few variables tested within any research studies. The field should move towards understanding a system of hormonal systems' interactions rather than maintaining hormone system silos.

Comparative Evaluation of the Effects of Legacy and New Generation Perfluoralkyl Substances (PFAS) on Thyroid Cells In Vitro

BACKGROUND

Per- and poly-fluorinated alkyl substances (PFAS) are environment-persitent emerging endocrine disrupting chemicals raising health concerns worldwide. Exposure to PFAS has been associated with the imbalance of thyroid hormones. However, available studies addressing the cell mechanism underlying thyroid disrupting feature of legacy PFAS, such as perfluoro-octanoic acid (PFOA), perfluoro-octane-sulfonic acid (PFOS), and the new generation substitutes, such as C6O4, are still lacking. In this study the potential disrupting effect of PFOA, PFOS, and C6O4 on a murine thyroid cell model was assessed.

METHODS

A rat FRTL-5 cell line was used as the normal thyroid follicular cell model. Cell iodide-uptake, induced by thyroid stimulating hormone (TSH), was used to assess the functional impact of PFAS exposure on cell function. Tetrazolium salt-based cell viability assay and merocyanine 540-based cell staining were used to address the possible involvement of cell toxicity and membrane biophysical properties on altered cell function. The possible direct interaction of PFAS with TSH-receptor (TSH-R) was investigated by computer-based molecular docking and analysis of molecular dynamics. Evaluation of intracellular cAMP levels and gene expression analysis were used to validate the direct impairment of TSH-R-mediated downstream events upon PFAS exposure.

RESULTS

Different from PFOS or C6O4, exposure to PFOA at a concentration ≥ 10 ng/mL was associated with significant impairment of the iodide uptake upon TSH stimulation (respectively: basal 100.0 ± 19.0%, CTRL + TSH 188.9 ± 7.8%, PFOA 10 ng/mL + TSH 120.4 ± 20.9%, p= 0.030 vs CTRL + TSH; PFOA 100 ng/mL + TSH 115,6 ± 12,3% p= 0.017 vs CTRL + TSH). No impairment of cell viability or membrane stability was observed. Computational analysis showed a possible direct differential interaction of C6O4, PFOA, and PFOS on a same binding site of the extracellular domain of TSH-R. Finally, exposure to PFOA was associated with a significant reduction of downstream intracellular cAMP levels and both sodium-iodide transporter and thyroperoxidase gene expression upon TSH-R stimulation.

CONCLUSIONS

Our data suggest that legacy and new generation PFAS can differentially influence TSH dependent signaling pathways through the direct interaction with TSH-R.

Thyroid hormones inhibit apoptosis of macrophage induced by oxidized low-density lipoprotein

Increasing evidence suggests that hypothyroidism aggravates atherosclerosis. Macrophage apoptosis plays a significant role in the development of atherosclerotic plaque. We aimed to explore the effect of thyroid hormones on macrophage apoptosis induced by oxidized low-density lipoprotein (oxLDL). Peripheral blood samples from 20 patients (normal group, hypothyroidism group, coronary artery disease [CAD] group, hypothyroidism + CAD group) were collected to perform messenger RNA microarray analysis. Bioinformatics analysis identified apoptosis and mitogen-activated protein kinase (MAPK) signaling as differentially expressed pathways between CAD and hypothyroidism + CAD group. In vitro, thyroid hormones concentration-dependently promoted cell survival and inhibited apoptosis in oxLDL-treated RAW264.7 macrophages, along with elevated extracellular signal-regulated kinases 1 and 2 (Erk1/2) phosphorylation. The STRING database showed an interaction of thyroid hormone receptor alpha1 (TRα1) and MAPK pathway. TRα1 knockdown increased cell apoptosis and decreased Erk1/2 phosphorylation. Erk1/2 inhibitor aggravated macrophage apoptosis. Moreover, thyroid hormones inhibited oxidative stress in oxLDL-treated macrophages. The study indicates that thyroid hormones concentration-dependently attenuate oxLDL-induced macrophage apoptosis through activating TRα1-Erk1/2 pathway and inhibiting oxidative stress, which implies a potential mechanism of hypothyroid-accelerated atherosclerosis.

Association of Thyroid Hormone Levels with Microvascular Complications in Euthyroid Type 2 Diabetes Mellitus Patients

PURPOSE

To examine the prevalence of different microvascular complications and investigate the association between thyroid hormones (THs) and these complications in euthyroid patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 248 T2DM patients were analyzed retrospectively for the study. All patients received a detailed and standard assessment to identify diabetic peripheral neuropathy (DPN), diabetic nephropathy (DN), and diabetic retinopathy (DR). Multivariate logistic regression was carried out to analyze the association between THs and diabetic microvascular complications.

RESULTS

The study found the prevalence of any microangiopathy to be 72.18% (n = 179). At the same time, the prevalence of DPN was 54.84% (n=136), while that of DN was 31.85% (n=79). Likewise, the prevalence of DR was 35.48% (n=88). The odds ratios (ORs) for free triiodothyronine (FT3) developing any microangiopathy, DPN, DN and DR were 0.200, 0.361, 0.310, and 0.588 (P<0.05), respectively. Also, the ORs for free thyroxine (FT4) developing any microangiopathy, DPN, DN and DR were 0.643, 0.800, 0.702 and 0.726 (P<0.05), respectively. Lastly, the ORs for thyroid-stimulating hormone (TSH) developing DPN was 1.57 (95% CI: 1.148-2.137, P=0.005).

CONCLUSION

The study concludes that serum FT3 and FT4 levels are negatively associated with any microangiopathy, DPN, DN and DR in euthyroid patients with T2DM, independent of traditional risk factors. However, the TSH levels are positively associated with DPN. Future larger sample-size studies are needed to confirm the relationship between thyroid hormone levels and microvascular complications in euthyroid patients with T2DM.

FT3/FT4 ratio is correlated with all-cause mortality, cardiovascular mortality, and cardiovascular disease risk: NHANES 2007-2012

BACKGROUND

Thyroid hormones play a vital role in maintaining the homeostasis of the cardiovascular system. The FT3/FT4 ratio can be used to evaluate the rate of T4-to-T3 conversion, reflecting the peripheral sensitivity of thyroid hormones. There is no study to investigate its relationship with death and cardiovascular disease (CVD) in the general population.

METHODS

This retrospective cohort study involved 8,018 participants with measured thyroid function and no prior thyroid disease who participated in the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2012. Mortality status was determined by routine follow-up using the National Death Index through December 31, 2015.

RESULTS

During a median of 87 months of follow-up, we observed 699 all-cause deaths, including 116 cardiovascular deaths. In multivariate adjusted models, higher free thyroxine (FT4) was linked to increased all-cause mortality (HR, 1.15 per SD; 95% CI, 1.09-1.22), cardiovascular mortality (HR, 1.18 per SD; 95% CI, 1.01-1.39), and CVD risk (HR, 1.17 per SD; 95% CI, 1.08-1.27). Higher free triiodothyronine (FT3) was linked to decreased all-cause mortality (HR 0.81 per SD; 95% CI, 0.70-0.93). Higher FT3/FT4 ratio was linked to decreased all-cause mortality (HR, 0.77 per SD; 95% CI, 0.69-0.85), cardiovascular mortality (HR, 0.79 per SD; 95% CI, 0.62-1.00), and CVD risk (HR, 0.82 per SD; 95% CI, 0.74-0.92). The FT3/FT4 ratio stratified findings were broadly consistent with the overall results.

CONCLUSIONS

FT3, FT4, and the FT3/FT4 ratio were all independent predictors of all-cause death. FT4 and the FT3/FT4 ratio, but not FT3, were independent predictors of cardiovascular mortality and CVD risk. Along with FT3 and FT4, we should pay equal attention to the FT3/FT4 ratio in the general population.

Evaluating health outcomes in the treatment of hypothyroidism

Clinical hypothyroidism is defined by the inadequate production of thyroid hormone from the thyroid gland to maintain normal organ system functions. For nearly all patients with clinical hypothyroidism, lifelong treatment with thyroid hormone replacement is required. The primary goal of treatment is to provide the appropriate daily dose of thyroid hormone to restore normal thyroid function for each individual patient. In current clinical practice, normalization of thyrotropin (TSH) level is the primary measure of effectiveness of treatment, however the use of a single biomarker to define adequate thyroid hormone replacement is being reevaluated. The assessment of clinical health outcomes and patient-reported outcomes (PROs), often within the context of intensity of treatment as defined by thyroid function tests (i.e., undertreatment, appropriate treatment, or overtreatment), may play a role in evaluating the effectiveness of treatment. The purpose of this narrative review is to summarize the prominent health outcomes literature in patients with treated hypothyroidism. To date, overall mortality, cardiovascular morbidity and mortality, bone health and cognitive function have been evaluated as endpoints in clinical outcomes studies in patients with treated hypothyroidism. More recent investigations have sought to establish the relationships between these end results and thyroid function during the treatment course. In addition to clinical event outcomes, patient-reported quality of life (QoL) has also been considered in the assessment of adequacy of hypothyroidism treatment. From a health care quality perspective, treatment of hypothyroidism should be evaluated not just on its effectiveness for the individual patients but also to the extent to which patients of different sociodemographic groups are treated equally. Ultimately, more research is needed to explore differences in health outcomes between different sociodemographic groups with hypothyroidism. Future prospective studies of treated hypothyroidism that integrate biochemical testing, PROs, and end result clinical outcomes could provide a more complete picture into the effectiveness of treatment of hypothyroidism.

Effect of levothyroxine replacement therapy in patients with subclinical hypothyroidism and chronic heart failure: A systematic review

BACKGROUND

Chronic heart failure (CHF) affects the health care system with high social and economic costs due to recurrent hospital admissions or frequent ambulatory reassessments. Subclinical hypothyroidism (SCH) is commonly observed in patients with CHF and negatively affects myocardial function and remodeling and, ultimately, increases the risk of hospitalizations and all-cause and cardiovascular (CV) mortality. The role of levothyroxine replacement on relevant CV outcomes in patients with SCH and CHF is unclear.

OBJECTIVE

To assess the effect of levothyroxine (compared to placebo or no treatment) on the incidence of all-cause and CV mortality, major adverse CV events, and heart failure in patients with SCH and CHF.

METHODS

PubMed/MEDLINE, Cochrane Library, and ClinicalTrial.gov were searched for randomized clinical trials, non-randomized observational, multicentric, and comparative studies. No language restrictions were included. After duplicate removal, articles were screened and extracted for the synthesis according to a hierarchical strategy that included title, abstract, and full-text appraisal. The risk of bias was assessed by RoB2 and ROBIN-I tools. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was applied to rate the quality of evidence and grade the strength of recommendations.

RESULTS

Two trials were included in the systematic review with considerable indirectness and inaccuracy that down-graded the level of evidence.

DISCUSSION

No evidence supports the use of levothyroxine for treating SCH in CHF due to the lack of reliable and well-designed clinical trials.

CONCLUSION

CV outcome and dose-response trials are needed to understand better the role of levothyroxine replacement treatment for a safer prescription in this clinical setting.

Nickel Sulfate Induces Autophagy in Human Thyroid Follicular Epithelial Cells

Nickel is an industrial and environmental toxic metal, which is toxic to humans in certain forms at high doses. Here, we investigated the cytotoxic effects of nickel sulfate (NiSO₄) exposure on the human thyroid follicular epithelial cells (Nthy-ori 3-1) and its underlying toxicological mechanisms. The results showed that NiSO₄ reduced the cell viability of Nthy-ori 3-1 cells in a dose- and time-dependent manner, inducing S and G2/M phases cell-cycle arrest and apoptosis. Electron microscopy demonstrated that abundant autophagic vacuoles were found in Nthy-ori 3-1 cells after NiSO₄ treatment. Accordingly, exposure of Nthy-ori 3-1 cells to NiSO₄ resulted in a dose-dependent increase of LC3II/I ratio, an induction of Beclin-1 expression, and a decrease in p62 levels. Blockade of autophagy with 3-methyladenine (3-MA) potentiated the NiSO₄-induced apoptotic cell death, while induction of autophagy significantly alleviated toxicity of NiSO₄. From a molecular standpoint, NiSO₄ markedly promoted the activation of p38 and IKKβ by increasing their phosphorylation. In conclusion, we showed that autophagy was induced to protect thyroid cells from Ni²⁺ mediated apoptosis, thus providing rational strategy to prevent against nickel toxicity in the thyroid.

FT4/FT3 ratio: A novel biomarker predicts coronary microvascular dysfunction (CMD) in euthyroid INOCA patients

BACKGROUND

Ischemia and no obstructive coronary artery disease (INOCA) patients who presented coronary microvascular dysfunction (CMD) demonstrate a poor prognosis, yet the risk factors for CMD remain unclear. Subtle changes in thyroid hormone levels within the normal range, especially the free thyroxine (FT4)/free triiodothyronine (FT3) ratio, have been shown to regulate the cardiovascular system. This prospective study investigated the correlation between FT4/FT3 ratio and CMD in euthyroid patients with INOCA.

METHODS

This prospective study (www.chictr.org.cn/, ChiCTR2000037112) recruited patients with myocardial ischemia symptoms who underwent both coronary angiography (CAG) and myocardial perfusion imaging (MPI) with dynamic single-photon emission computed tomography (D-SPECT). INOCA was defined as coronary stenosis< 50% and CMD was defined as coronary flow reserve (CFR)<2.5. All patients were excluded from abnormal thyroid function and thyroid disease history.

RESULTS

Among 71 INOCA patients (15 [21.1%] CMD), FT4 and FT4/FT3 ratio in CMD group were significantly higher and both showed significantly moderate correlation with CFR (r=-0.25, p=0.03; r=-0.34, p=0.003, respectively). The ROC curve revealed that FT4/FT3 ratio had the highest efficacy for predicting CMD with an optimized cutoff value>3.39 (AUC 0.78, p<0.001, sensitivity, 80.0%; specificity, 71.4%). Multivariate logistic regression showed that FT4/FT3 ratio was an independent predictor of CMD (OR 7.62, 95% CI 1.12-51.89, p=0.038, P for trend=0.006).

CONCLUSION

In euthyroid INOCA patients, increased FT4/FT3 ratio levels are associated with the occurrence of CMD, presenting a novel biomarker for improving the risk stratification.

Perfluoroalkyl substances and thyroid stimulating hormone levels in a highly exposed population in the Veneto Region

BACKGROUND

Per- and poly-fluoroalkyl substances (PFAS) are persistent and widespread environmental pollutants. People living in Veneto Region (Italy) have been exposed from the late 1970s to 2013 to elevated concentrations of PFAS through drinking water. The effect of PFAS on thyroid function is still controversial and studies focusing on thyroid stimulating hormone (TSH) have shown inconsistent results. The aim of this study was to evaluate the association between serum PFAS and TSH levels and its dose-response relationship in a large population of highly exposed individuals.

METHODS

A cross-sectional study was conducted on 21,424 individuals aged 14-39 living in the contaminated area. In the main analysis, participants with prevalent thyroid disease and pregnant women were excluded. Serum levels of perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS) and perfluorononanoic acid (PFNA) were measured. Generalized Additive Models were used to evaluate the association between TSH levels and serum PFAS, using thin plate spline smooth terms to model the potential non-linear relationship. Models were stratified by sex and age group and adjusted for potential confounders. A secondary analysis was conducted to evaluate the association between PFAS with prevalent self-reported thyroid disorders.

RESULTS

We found no association between TSH and any type of PFAS among adolescents or women. A decrease in TSH concentration was observed in association with an IQR increase in PFHxS and a mild decrease in TSH at low levels of PFOA, PFOS and PFHxS among male adults. Self-reported thyroid disease was more common among women with higher levels of PFNA concentrations, whereas all other PFAS were not associated with thyroid diseases regardless of sex or age.

CONCLUSIONS

Overall there is no evidence of an association between TSH and PFAS. However, some results are suggestive of a possible inverse association of TSH with PFOA, PFOS and PFHxS among adult males.

Study of the Associations between Color Doppler Ultrasound Grading of Hyperthyroidism and Biochemical Data on Thyroid Function

OBJECTIVE

The main study objective was to investigate the correlation between the color Doppler ultrasound grading of hyperthyroidism and the biochemical data of thyroid function.

METHODS

Seventy-six patients were diagnosed with hyperthyroidism based on clinical and laboratory data at our hospital. The patients were examined using color Doppler ultrasound and laboratory investigations before starting ¹³¹I treatment. First, patients were divided into two groups based on the blood flow distribution determined by ultrasound. If the blood flow signal in the parenchyma was scattered and thinned, with dispersive points and discontinuous streaky distribution, the blood flow distribution area in the sample frame was less than or equal to 1/2 of the sample frame area and was judged to be level 1. If the parenchyma was filled with diffuse blood flow signals or if most areas had depicted rich blood flow distribution when the area of blood flow distribution in the sampling frame was greater than 1/2 of the sampling frame area, it was judged to be level 2. Then, the correlations between color Doppler ultrasound grading and biochemical data of thyroid function were analyzed. The indices included FT3, FT4, TSH, anti-TG, anti-TPO, and TRAb. Parameters of thyroid homeostasis, including thyroid's secretory capacity (SPINA-GT), the total deiodinase activity (SPINA-GD), Jostel's TSH index, and the thyrotroph thyroid hormone sensitivity index (TTSI), were calculated and compared.

RESULTS

Correlations were noted between color Doppler ultrasound grading and FT3, FT4, TRAb, SPINA-GT, TSHI, and TTSI. Moreover, FT3, FT4, TRAb, SPINA-GT, TSHI, and TTSI were higher in level 2 patients compared with level 1 patients.

CONCLUSION

Correlations were noted between color Doppler ultrasound grading and biochemical data of thyroid function.

Association of Thyroid Function with Blood Pressure and Cardiovascular Disease: A Mendelian Randomization

Thyroid function has a widespread effect on the cardiometabolic system. However, the causal association between either subclinical hyper- or hypothyroidism and the thyroid hormones with blood pressure (BP) and cardiovascular diseases (CVD) is not clear. We aim to investigate this in a two-sample Mendelian randomization (MR) study. Single nucleotide polymorphisms (SNPs) associated with thyroid-stimulating hormone (TSH), free tetraiodothyronine (FT4), hyper- and hypothyroidism, and anti-thyroid peroxidase antibodies (TPOAb), from genome-wide association studies (GWAS), were selected as MR instrumental variables. SNPs-outcome (BP, CVD) associations were evaluated in a large-scale cohort, the Malmö Diet and Cancer Study (n = 29,298). Causal estimates were computed by inverse-variance weighted (IVW), weighted median, and MR-Egger approaches. Genetically increased levels of TSH were associated with decreased systolic BP and with a lower risk of atrial fibrillation. Hyperthyroidism and TPOAb were associated with a lower risk of atrial fibrillation. Our data support a causal association between genetically decreased levels of TSH and both atrial fibrillation and systolic BP. The lack of significance after Bonferroni correction and the sensitivity analyses suggesting pleiotropy, should prompt us to be cautious in their interpretation. Nevertheless, these findings offer mechanistic insight into the etiology of CVD. Further work into the genes involved in thyroid functions and their relation to cardiovascular outcomes may highlight pathways for targeted intervention.

Serum free triiodothyronine is inversely associated with diabetic peripheral neuropathy but not with carotid atherosclerotic lesions in euthyroid patients with type 2 diabetes

BACKGROUND

The associations between serum free triiodothyronine (FT3) and diabetic peripheral neuropatprohy (DPN)/carotid atherosclerotic lesions in euthyroid patients with type 2 diabetes are still unclear. The purpose of our study was to explore the relations of FT3 to DPN and carotid atherosclerotic lesions in Chinese type 2 diabetes inpatients with euthyroid function.

METHODS

2477 euthyroid inpatients with type 2 diabetes were recruited and they were stratified into quartiles by FT3 levels in this cross-sectional study. Peripheral neuropathy was assessed by neurological symptoms and signs as well as nerve conduction velocity tests. Carotid atherosclerotic lesions, including carotid intima-media thickness, plaque and stenosis, were evaluated by Doppler ultrasound.

RESULTS

The prevalence of DPN in type 2 diabetic patients exhibited the significant decrease across the FT3 quartiles (23.5%, 20.9%, 18.8%, and 11.2%, respectively, p < 0.001). Multiple logistical regression analysis also revealed that FT3 quartiles were significantly and inversely associated with DPN. Compared with the subjects in the highest FT3 quartile, the adjusted odds ratios (95% confidence interval) of DPN from the first to third FT3 quartile were successively 2.338 (1.407-3.884), 1.903 (1.134-3.194) and 1.598 (0.960-1.125). The patients with DPN had significantly higher prevalence of carotid atherosclerotic lesions compared with non-DPN patients. However, no statistical association was observed between FT3 quartiles and carotid atherosclerotic lesions after adjusting for confounder factors.

CONCLUSIONS

Lower FT3 within the normal range was independently associated with DPN, but not with carotid atherosclerotic lesions in Chinese euthyroid inpatients with type 2 diabetes.

Impact of low triiodothyronine syndrome on long-term outcomes in patients with myocardial infarction with nonobstructive coronary arteries

BACKGROUND

Low triiodothyronine syndrome (LT3S), frequently seen in patients with acute myocardial infarction (AMI), has been regarded as a predictor of poor outcomes after AMI. However, little is known about the prognostic value of LT3S in euthyroid patients with myocardial infarction with nonobstructive coronary arteries (MINOCA).

METHODS

A total of 1162 MINOCA patients were enrolled and divided into LT3S and no-LT3S groups. LT3S was defined as decreased free T3 (fT3 < 2.36 pg/mL) with normal values of thyroid-stimulating hormone. The primary endpoint was a composite of major adverse cardiovascular events (MACE), including all-cause death, nonfatal MI, stroke, revascularization, and hospitalization for unstable angina or heart failure. Kaplan-Meier, Cox regression, propensity score matching (PSM), and receiver-operating characteristic analyses were performed.

RESULTS

Patients with LT3S (prevalence of 17.5%) had a significantly higher incidence of MACE (19.6% vs. 12.9%; p = .013) than patients without during the median follow-up of 41.7 months. LT3S was closely associated with an increased risk of MACE even after multivariable adjustment (HR 1.50, 95% CI: 1.03-2.18, p = .037). After PSM, 197 pairs of patients with or without LT3S were identified, and LT3S remained a robust risk factor of worse outcomes (HR 1.53, 95% CI: 1.02-2.65, p = .042). Moreover, LT3S had an area under the curve (AUC) of 0.60 for predicting MACE. When adding LT3S to the thrombolysis in myocardial infarction (TIMI) risk score, the combined model yielded a significant improvement in discrimination for MACE.

CONCLUSIONS

LT3S was independently associated with poor outcomes after MINOCA. Routine assessment of LT3S may provide valuable prognostic information in this specific population.

Pericardial Tamponade and Elevated Serum CA-125 Level in Inadequately Treated Hypothyroidism

Cardiac tamponade is a medical emergency and must be managed promptly, and reaching a diagnosis is imperative to prevent recurrence. Herein, we present a case of a young female patient that presented with progressive shortness of breath and abdominal distension and was found to have cardiac tamponade with the finding of elevation of a blood tumor marker, CA-125, in the setting of nonadherence to thyroid replacement therapy. She was managed by surgical pericardial window and abdominal paracentesis, with replacement of thyroid hormones leading to resolution of the tamponade and ascites. CA-125 elevation associated with cardiac tamponade and myxedema ascites due to hypothyroidism is very rare, and we aim to shed light on the importance of having a broad differential when approaching cardiac tamponade and understand the association between CA-125 and hypothyroidism.

Cardiovascular Outcomes in Thyroid Cancer Patients Treated With Thyroidectomy: A Meta-analysis

CONTEXT

Thyroid dysfunction is associated with an increased risk of cardiovascular disease (CVD) in the general population; however, it remains controversial whether differentiated thyroid cancer (DTC) treatment, including thyroidectomy and thyroid-stimulating hormone suppression, further increases the risk of CVD.

OBJECTIVE

This study aimed to evaluate the risk of CVD in patients with DTC.

METHODS

We performed a review of observational studies on associations between DTC and cardiovascular outcomes, indexed in MEDLINE, Embase, and Web of Science. We excluded studies that evaluated CVD as comorbidity before DTC diagnosis and those that used active surveillance without thyroidectomy as an intervention. Risk estimates were pooled using random- and fixed-effects models when 3 or more studies reported on the outcome of interest. Echocardiographic and hemodynamic parameters were examined.

RESULTS

Eighteen studies were included in the quantitative analysis (193 320 cases with DTC and 225 575 healthy controls). DTC was associated with an increased risk of atrial fibrillation (pooled risk ratio [RR] = 1.55 [95% CI: 1.30-1.84]), coronary artery disease (RR = 1.10 [1.00-1.21]), cerebrovascular accidents (RR = 1.15 [1.09-1.20]), and all-cause mortality (RR = 1.95 [1.03-3.69]). DTC was associated with higher diastolic blood pressure (standardized mean difference [SMD], 0.22 [0.01-0.42]), heart rate (0.37 [0.17-0.57]), left ventricular mass index (0.66 [0.45-0.88]), and interventricular septal thickness (0.91 [0.33-1.49]) and lower early to late ventricular filling velocities (-0.42 [-0.79 to -0.05]), but not with ejection fraction.

CONCLUSION

Patients with DTC are at an increased risk of atrial fibrillation, CVD, increased heart rate, and left ventricular mass development.

Development of Triiodothyronine Polymeric Nanoparticles for Targeted Delivery in the Cardioprotection against Ischemic Insult

Ischemic heart disease is the main cause of death globally. Cardioprotection is the process whereby mechanisms that reduce myocardial damage, and activate protective factors, contribute to the preservation of the heart. Targeting these processes could be a new strategy in the treatment of post-ischemic heart failure (HF). Triiodothyronine (T3) and thyroxine (T4), which have multiple effects on the heart, prevent myocardial damage. This study describes the formulation, and characterization, of chemically modified polymeric nanoparticles incorporating T3, to target the thyroid hormone receptors. Modified T3 was conjugated to polylactide-co-glycolide (PLGA) to facilitate T3 delivery and restrict its nuclear translocation. Modified T3 and PLGA-T3 was characterized with ¹H-NMR. The protective role of synthesized phosphocreatine (PCr) encapsulated PLGA-T3 nanoparticles (PLGA-T3/PCr NPs) and PLGA-T3 nanoparticles (PLGA-T3 NPs) in hypoxia-mediated cardiac cell insults was investigated. The results showed that PLGA-T3/PCr NPs represent a potentially new therapeutic agent for the control of tissue damage in cardiac ischemia and resuscitation.

Prevalence and mortality of cardiovascular events in patients with hyperthyroidism: a nationwide cohort study in the United States

Background

Little is known about the implications of hyperthyroidism on cardiovascular diseases like myocardial infarctions (MI), ischemic strokes, and hemorrhagic strokes. Previous studies implicate hyperthyroidism as a risk factor for MI and ischemic stroke. Cardiovascular disease is the leading cause of death in the US, and the possibility of hyperthyroidism contributing to this disease burden warrants investigation in a US patient population.

Methods

The National Readmission Database (NRD) from 2010 to 2017 was used to identify adults who had a new-onset diagnosis of MI, ischemic stroke, or hemorrhagic stroke. Risk factors for mortality, prolonged hospital stay, and hospital cost were analyzed with binary logistic regression.

Results

A total of 278,609,748 hospital records were reviewed. Of these, 15,685,461 were hospitalized for adverse cardiovascular events with concomitant hyperthyroidism, roughly 4.5 per 1,000 cases. Patients with MI and hemorrhagic stroke with thyrotoxicosis had a lower mortality rate than euthyroid patients (OR 0.81, 95% CI: 0.78-0.84, P<0.001 and OR 0.72, 95% CI: 0.67-0.77, P<0.001, respectively). Thyrotoxicosis was associated with increased hospital stay (MI: OR 1.35, 95% CI: 1.32-1.38, P<0.001; ischemic: OR 1.38, 95% CI: 1.35-1.41, P<0.001; hemorrhagic: OR 1.33, 95% CI: 1.25-1.40, P<0.001), expenditures in ischemic (OR 1.31, 95% CI: 1.28-1.34, P<0.001) and hemorrhagic stroke patients (OR 1.18, 95% CI: 1.12-1.24, P<0.001).

Conclusions

Patients that experienced MI or hemorrhagic stroke with concomitant thyrotoxicosis were observed to have a lower mortality rate than euthyroid patients but had with an increased length of hospital stay. Patients who had ischemic or hemorrhagic stroke with thyrotoxicosis had a significantly higher hospital cost. The hyperdynamic state underlying hyperthyroidism may be protective in these adverse events. Further studies into these physiological changes are warranted.

Levothyroxine Treatment and the Risk of Cardiac Arrhythmias - Focus on the Patient Submitted to Thyroid Surgery

Levothyroxine (LT4) is used to treat frequently encountered endocrinopathies such as thyroid diseases. It is regularly used in clinical (overt) hypothyroidism cases and subclinical (latent) hypothyroidism cases in the last decade. Suppressive LT4 therapy is also part of the medical regimen used to manage thyroid malignancies after a thyroidectomy. LT4 treatment possesses dual effects: substituting new-onset thyroid hormone deficiency and suppressing the local and distant malignancy spreading in cancer. It is the practice to administer LT4 in less-than-high suppressive doses for growth control of thyroid nodules and goiter, even in patients with preserved thyroid function. Despite its approved safety for clinical use, LT4 can sometimes induce side-effects, more often recorded with patients under treatment with LT4 suppressive doses than in unintentionally LT4-overdosed patients. Cardiac arrhythmias and the deterioration of osteoporosis are the most frequently documented side-effects of LT4 therapy. It also lowers the threshold for the onset or aggravation of cardiac arrhythmias for patients with pre-existing heart diseases. To improve the quality of life in LT4-substituted patients, clinicians often prescribe higher doses of LT4 to reach low normal TSH levels to achieve cellular euthyroidism. In such circumstances, the risk of cardiac arrhythmias, particularly atrial fibrillation, increases, and the combined use of LT4 and triiodothyronine further complicates such risk. This review summarizes the relevant available data related to LT4 suppressive treatment and the associated risk of cardiac arrhythmia.

Incidence of Post-Heart Transplant Chronic Thyroiditis and Its Association With Pretransplant Amiodarone Use

BACKGROUND

Chronic thyroiditis (CT) is a common cause of thyroid dysfunction and could therefore adversely affect outcomes in patients undergoing heart transplant (HT). The incidence of post-HT CT and whether amiodarone, a commonly used anti-arrhythmic drug in patients with heart failure during pre-HT period, is associated with the development of post-HT CT are unknown.

METHODS

A retrospective review of HT recipients from February 2, 2010 to October 16, 2018 was performed. Patients who lacked relevant pre-/post-HT records, underwent thyroidectomy, had pre-HT thyroid dysfunction or thyroiditis within 15 days post-HT, and those on amiodarone during the post-HT period were excluded, yielding a final cohort of 75 patients.

RESULTS

Patients had a mean age of 63.3 ± 1.4 years and were predominantly male (90.7%) and white (80%). The incidence of post-HT CT was 32% with the majority (83.3%) manifesting as hypothyroidism. Median time to diagnosis of CT after transplant was 10.2 months (interquartile range, 4-27.4). Additionally, the CT group had higher pre-HT use of amiodarone (non-CT vs CT: 21.6% vs 50%, P = .01), higher prevalence of atrial fibrillation (non-CT vs CT: 23.5% vs 45.8%; P = .05), and more stage IV/V chronic kidney disease (non-CT vs CT: 2% vs 16.7%, P = .02). On multivariate analysis, pre-HT amiodarone use was associated with the development of post-HT CT after adjustment for age, sex, and chronic kidney disease (odds ratio, 3.65; 95% CI, 1.17-11.44; P = .03).

CONCLUSION

The incidence of post-HT CT is high and is strongly associated with pre-HT amiodarone use underpinning the importance of closely following the post-HT thyroid profile in these patients.

Selenoprotein DIO2 Is a Regulator of Mitochondrial Function, Morphology and UPRmt in Human Cardiomyocytes

Members of the fetal-gene-program may act as regulatory components to impede deleterious events occurring with cardiac remodeling, and constitute potential novel therapeutic heart failure (HF) targets. Mitochondrial energy derangements occur both during early fetal development and in patients with HF. Here we aim to elucidate the role of DIO2, a member of the fetal-gene-program, in pluripotent stem cell (PSC)-derived human cardiomyocytes and on mitochondrial dynamics and energetics, specifically. RNA sequencing and pathway enrichment analysis was performed on mouse cardiac tissue at different time points during development, adult age, and ischemia-induced HF. To determine the function of DIO2 in cardiomyocytes, a stable human hPSC-line with a DIO2 knockdown was made using a short harpin sequence. Firstly, we showed the selenoprotein, type II deiodinase (DIO2): the enzyme responsible for the tissue-specific conversion of inactive (T4) into active thyroid hormone (T3), to be a member of the fetal-gene-program. Secondly, silencing DIO2 resulted in an increased reactive oxygen species, impaired activation of the mitochondrial unfolded protein response, severely impaired mitochondrial respiration and reduced cellular viability. Microscopical 3D reconstruction of the mitochondrial network displayed substantial mitochondrial fragmentation. Summarizing, we identified DIO2 to be a member of the fetal-gene-program and as a key regulator of mitochondrial performance in human cardiomyocytes. Our results suggest a key position of human DIO2 as a regulator of mitochondrial function in human cardiomyocytes.

Galectin-3, metalloproteinase-2 and cardiovascular disease were independently associated with metalloproteinase-14 in patients with type 1 diabetes: a cross sectional study

BACKGROUND

Type 1 diabetes (T1D) is a major risk factor for cardiovascular disease (CVD). Matrix metalloproteinase-14 (MMP-14) is involved in the development of atherosclerosis and CVD. The main aim was to explore the associations between MMP-14 and selected inflammatory and metabolic variables, CVD, depression, physical activity, smoking and medication in patients with T1D. The secondary aim was to explore associations with CVD.

METHODS

Cross-sectional design. The participants were consecutively recruited from one specialist diabetes out-patient clinic. Depression was assessed by a self-report instrument. Blood samples, anthropometrics and blood pressure were collected, supplemented with data from electronic health records. High MMP-14 was defined as  ≥  5.81 ng/mL. Non-parametric tests, Chi² tests and multiple logistic regression analyses were performed.

RESULTS

Two hundred and sixty-eighth T1D patients aged 18-59 years participated (men 58%, high MMP-14 25%, CVD 3%). Sixty-seven patients with high MMP-14, compared to 201 patients with lower MMP-14, had higher prevalence of CVD (8% versus 1%, p  =  0.012), and had higher levels of galectin-3 (p  <  0.001) and MMP-2 (p  =  0.018). Seven patients with CVD, compared to 261 without, were older (p  =  0.003), had longer diabetes duration (p  =  0.027), and had higher prevalence of high MMP-14 (71% versus 24%, p  =  0.012), abdominal obesity (p  =  0.014), depression (p  =  0.022), usage of antidepressants (p  =  0.008), antihypertensive drugs (p  =  0.037) and statins (p  =  0.049). Galectin-3 (per ng/mL) [adjusted odds ratio (AOR) 2.19, p  <  0.001], CVD (AOR 8.1, p  =  0.027), and MMP-2 (per ng/mL) (AOR 1.01, p  =  0.044) were associated with high MMP-14. Depression (AOR 17.4, p  =  0.006), abdominal obesity (15.8, p  =  0.006), high MMP-14 (AOR 14.2, p  =  0.008), and diabetes duration (AOR 1.10, p  =  0.012) were associated with CVD.

CONCLUSIONS

The main findings of this study were that galecin-3, MMP-2, and CVD were independently associated with high levels of MMP-14 in T1D patients. The association between MMP-14 and galectin-3 is a new finding. No traditional risk factors for CVD were associated with MMP-14. Depression, abdominal obesity and MMP-14 were independently associated with CVD.

Relationship between Blood Trihalomethane Concentrations and Serum Thyroid Function Measures in U.S. Adults

Toxicological studies show that exposure to disinfection byproducts, including trihalomethanes (THMs), negatively affects thyroid function; however, few epidemiological studies have explored this link. This study included 2233 adults (ages ≥20 years) from the 2007-2008 National Health and Nutrition Examination Survey (NHANES) who were measured for blood THM concentrations [chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), or bromoform (TBM)] and serum thyroid function biomarkers [thyroid-stimulating hormone, free thyroxine (FT4), total thyroxine (TT4), free triiodothyronine (FT3), total triiodothyronine (TT3), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb)]. Multivariable linear regression models showed positive associations between blood TCM, BDCM, and total THMs (the sum of all four THMs) concentrations and serum FT4, whereas inverse associations were found between blood DBCM and total brominated THM (Br-THM; the sum of BDCM, DBCM, and TBM) concentrations and serum TT3 (all p < 0.05). Besides, positive associations were observed between blood TCM concentrations and FT4/FT3 ratio, between BDCM, DBCM, and Br-THM concentrations and TT4/TT3 ratio, and between DBCM and Br-THM concentrations and FT3/TT3 ratio (all p < 0.05). Blood THM concentrations were unrelated to the serum levels of thyroid autoantibodies TgAb or TPOAb. In summary, exposure to THMs was associated with altered serum biomarkers of thyroid function but not with thyroid autoimmunity among U.S. adults.

Thyroid Hormone Plays an Important Role in Cardiac Function: From Bench to Bedside

Thyroid hormones (THs) are synthesized in the thyroid gland, and they circulate in the blood to regulate cells, tissues, and organs in the body. In particular, they exert several effects on the cardiovascular system. It is well known that THs raise the heart rate and cardiac contractility, improve the systolic and diastolic function of the heart, and decrease systemic vascular resistance. In the past 30 years, some researchers have studied the molecular pathways that mediate the role of TH in the cardiovascular system, to better understand its mechanisms of action. Two types of mechanisms, which are genomic and non-genomic pathways, underlie the effects of THs on cardiomyocytes. In this review, we summarize the current knowledge of the action of THs in the cardiac function, the clinical manifestation and parameters of their hemodynamics, and treatment principles for patients with hyperthyroid- or hypothyroid-associated heart disease. We also describe the cardiovascular drugs that induce thyroid dysfunction and explain the mechanism underlying the thyroid toxicity of amiodarone, which is considered the most effective antiarrhythmic agent. Finally, we discuss the recent reports on the involvement of thyroid hormones in the regulation of myocardial regeneration and metabolism in the adult heart.

The Association between Thyroid-Stimulating Hormone and Long-Term Outcomes in Patients with ST Segment Elevation Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention

Objective

Thyroid hormones are closely related to the cardiovascular system. Our study aimed to explore the impact of admission thyroid-stimulating hormone (TSH) levels on long-term outcomes in patients with acute ST segment elevation myocardial infarction (STEMI) by detailed stratifications of TSH.

Methods

Consecutive STEMI patients admitted to our hospital were divided into four groups: Group 1 (TSH <0.35 mIU/L), Group 2 (TSH 0.35–1.0 mIU/L), Group 3 (TSH 1.0–3.5 mIU/L), and Group 4 (TSH >3.5 mIU/L). The primary endpoint was all-cause mortality during follow-up, and the median follow-up was 2.5 years. Cox proportional hazard regression models were performed to identify the prognostic value of TSH.

Results

A total of 1186 patients were included. Group 4 was presented with higher systolic and diastolic blood pressure (all P < 0.001), and Group 1 had more patients complicated by heart failure (Killip class >I, P = 0.014). During follow-up, 138 deaths occurred. Patients in Group 4 had the worst long-term outcomes (P < 0.001). The cumulative survival in Group 4 was remarkably lower (Log rank P < 0.001), whereas the other three groups were comparable (Log rank P = 0.365). Through Cox regression analysis, only TSH >3.5 mIU/L was identified as an independent risk factor for long-term mortality after STEMI.

Conclusion

Only TSH elevation beyond the normal range was associated with worse long-term prognosis in STEMI patients, while high-normal TSH or reduced TSH did not alter long-term prognosis of STEMI patients. TSH >3.5 mIU/L was an independent risk factor for long-term mortality in STEMI.

Age- and sex-specific reference intervals for thyroid hormones in a Chinese pediatrics: a prospective observational study of 1,279 healthy children

BACKGROUND

Thyroid hormones are essential for early neurocognitive development and growth and development in childhood and adolescence. However, the reference intervals (RIs) for thyroid hormones in Chinese pediatric individuals remain unclear. This study aimed to establish thyroid hormone RIs for a Chinese pediatric population according to appropriate age- and sex-specific partitioning.

METHODS

In this prospective observational study, a total of 1,279 healthy children (singletons, aged from 1 day to 12 years) were recruited, and serum samples were analyzed on a Mindray automated chemiluminescence immunoassay analyzer CL-6000i for thyroid hormone detection, including thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), total triiodothyronine (T3), and total thyroxine (T4). Age and sex-specific RIs were established, and the corresponding 95% confidence intervals (CIs) were calculated in accordance with the Clinical Laboratory Standards Institute (CLSI) document C28-A3 guidelines.

RESULTS

Quantile testing revealed that the median (P50) and RIs [2.5^th percentile (P2.5)-97.5^th percentile (P97.5)] for TSH, FT3, T3, and T4 of males differed significantly from those of females (P<0.05), except for FT4 (P=0.483). For FT3 and T3, the RIs of males were higher than that of females, and the RI of T4 for males was narrower and higher than that of females [P2.5-P97.5: 72.33-171.60 vs. 72.31-176.27 nmol/L; P50: 116.75 vs. 113.47 nmol/L, P=0.011]. RIs for TSH, FT3, FT4, T3, and T4 showed sex- and age-specific properties and displayed a wide variation during the first month of life but gradually narrowed and concentrated with increasing age. In addition, RIs of TSH, FT3, FT4, and T3 in males differed significantly from females in the first month of life (TSH: 1.46-10.87 vs. 1.08-11.35 mIU/L; FT3: 2.96-7.08 vs. 2.35-7.27 pmol/L, FT4: 13.34-28.65 vs. 13.82-31.83 pmol/L; T3: 0.83-2.33 vs. 0.72-2.46 nmol/L). The RI of T4 also exhibited a difference between males and females in the 9- to 12-year age group (59.31-150.72 vs. 63.29-146.94 pmol/L for males and females, respectively).

CONCLUSIONS

Pediatric RIs of thyroid hormones display age- and sex-specific trends. The RIs established in this study will improve the accuracy of TSH assay result interpretations and clinical decision-making in clinical laboratories that utilize the Mindray analytical platform.

Acute coronary syndrome with severe atherosclerotic and hyperthyroidism: A case report

BACKGROUND

Acute coronary syndrome (ACS) encompasses a spectrum of cardiovascular emergencies arising from the obstruction of coronary artery blood flow and acute myocardial ischemia. Recent studies have revealed that thyroid function is closely related to ACS. However, only a few reports of thyrotoxicosis-induced ACS with severe atherosclerosis have been reported.

CASE SUMMARY

A 33-year-old man, who had a history of hyperthyroidism without taking any antithyroid drugs and no history of coronary heart disease, experienced neck pain with occasional heart palpitations starting 3 mo prior that were aggravated after an activity. As the symptoms worsened at 21 d prior, he went to a hospital for treatment. The electrocardiogram examination showed a multilead ST segment elevation and pathological Q waves. Based on these findings and his symptoms, the patient was diagnosed with a suspected myocardial infarction and transferred to our hospital on July 2, 2020. He was diagnosed with a rare case of ACS due to coronary artery atherosclerosis in the anterior descending artery complicated by hyperthyroidism. A paclitaxel-coated drug balloon was used for treatment to avoid the use of metal stents, thus reducing the time of antiplatelet therapy and facilitating the continued treatment of hyperthyroidism. The 9-mo follow-up showed favorable results.

CONCLUSION

This case highlights that atherosclerosis is a cause of ACS that cannot be ignored even in a patient with hyperthyroidism.

The Association of Thyroid Hormones with Cardiogenic Shock and Prognosis in Patients with ST Segment Elevation Myocardial Infarction (STEMI) Treated with Primary PCI

BACKGROUND

Cardiogenic shock (CS) is the leading cause of the death in patients with ST elevation myocardial infarction (STEMI). Thyroid dysfunction is related to prognosis of patients with myocardial infarction. Hence, the aim of this study is to explore the relationship between thyroid hormones (free triiodothyronine [FT3] and free thyroxine [FT4]) and CS.

METHOD

A total of 1270 patients with STEMI treated with percutaneous coronary intervention (PCI) were consecutively enrolled in our study. Patients were classified into two groups according to with or without CS during hospitalization. Stepwise multivariate logistic analysis was conducted to investigate the association of thyroid hormones and CS. Restricted cubic spline method was employed to further explore relationship between CS and thyroid hormones.

RESULTS

Patients who developed CS (n=103) had lower FT3 and higher FT4 on admission. The stepwise logistic analysis showed both FT3 (P=0.038) and FT4 (P=0.024) were independently related to CS. Restricted cubic splines indicated that lower FT3 (<2.25 pg/ml) or higher FT4 (>1.25 ng/dl) was correlated with higher prevalence of CS. Over 2.5 years' follow-up, patients (n=294) with low FT3 (<2.85 pg/ml) and high FT4 (>=0.88 ng/dl) had the highest all-cause mortality (18.2%), whereas patients (n=293) with high FT3 and low FT4 had the lowest all-cause mortality (3.8%) (P for trend <0.0001).

CONCLUSIONS

Both FT3 and FT4 are independently associated with in-hospital CS development in patients with STEMI treated with PCI. Patients with lower range of FT3 and upper range of FT4 had the worst outcomes in a long-term follow-up.

Preliminary study of genome-wide association identified novel susceptibility genes for thyroid-related hormones in Chinese population

BACKGROUND

Thyroid hormones are critical regulators of metabolism, development and growth in mammals. However, the genetic association of thyroid-related hormones in the Chinese Han population is not fully understood.

OBJECTIVE

We aimed to identify the genetic loci associated with circulating thyroid-related hormones concentrations in the healthy Chinese Han population.

METHODS

Genotyping was performed in 124 individuals using Applied Biosystems™ Axiom™ PMDA, and 796,288 single nucleotide polymorphisms (SNPs) were available for the GWAS analysis. For replication, eleven SNPs were selected as candidate loci for genotyping by Agena MassARRAY platform in additional samples (313 subjects). The values of p < 5 × 10^- 6 suggest a suggestively significant genome-wide association with circulating thyroid-related hormones concentrations.

RESULTS

We identified that rs11178277 (PTPRB, p = 4.88 × 10^- 07) and rs7320337 (LMO7DN-KCTD12, p = 1.22 × 10^- 06) were associated with serum FT3 level. Three SNPs (rs4850041 in LOC105373394-LINC01249: p = 3.55 × 10^- 06, rs6867291 in LINC02208: p = 2.40 × 10^- 06 and rs79508321 in WWOX: p = 3.35 × 10^- 06) were related to circulating T3 level. Rs12474167 (LOC105373394-LINC01249, p = 1.65 × 10^- 06) and rs1864553 (IWS1, p = 2.00 × 10^- 06) were associated with circulating T4 concentration. The association with TGA concentration was for rs17163542 in DISP1 (p = 3.46 × 10^- 06) and rs12601151 in NOG-C17orf67 (p = 2.72 × 10^- 07). Two genome-level significant SNPs (rs2114707 in LINC01314, p = 1.69 × 10^- 06 and rs12601151, p = 1.41 × 10^- 07) associated with serum TMA concentration were identified. Moreover, rs6083269 (CST1-CST2, p = 3.36 × 10^- 06) was a significant locus for circulating TSH level. In replication, rs12601151 in NOG-C17orf67 was still associated with serum TGA level (p = 0.012).

CONCLUSIONS

The GWAS reported 11 new suggestively significant loci associated with circulating thyroid-related hormones levels among the Chinese Han population. These findings represented suggestively biological candidates for circulating thyroid-related hormones levels and provided new insights into the mechanisms of regulating serum TGA concentration.

Vitamin D, Thyroid Hormones and Cardiovascular Risk: Exploring the Components of This Novel Disease Triangle

The role of thyroid hormones (THs) in the cardiovascular (CV) system, through several direct and indirect effects is recognized. Even very small modification in TH levels (as those observed in subclinical hypothyroidism or hyperthyroidism, and low triiodothyronine syndrome) may adversely affect the CV system, whereas thyroid hormones benefit the CV system and improve the prognosis. There is also evidence of vitamin D effects on cardiometabolic disease (e.g., through modulation of endothelial and smooth muscle cell activity, renin-angiotensin-aldosterone system, nitric oxide, oxidative stress, and inflammatory response), as well as an association between vitamin D [25(OH)D] deficiency and autoimmune thyroid diseases or cancer, and a relationship between vitamin D concentration and titers of antibodies and thyroid autoimmunity replacement. Interestingly, experimental data indicate a direct effect of vitamin D on Type 2 deiodinase expression causing subsequential peripheral conversion of T4 into T3. However, the functional links among THs, vitamin D and the cardiovascular system, and clinical effects of coexisting abnormalities in this new troublesome triad, have not yet been reviewed. The main aim of this review is to discuss pathophysiology of this relationship, proposing new mechanistic insights involving vitamin D in the modulation of cardiometabolic disease and thyroid profile.

Hypothyroid cardiomyopathy: A reversible phenocopy of hypertrophic cardiomyopathy

We present the case of a 46-year-old patient with hypothyroidism secondary to Hashimoto's thyroiditis who was admitted with decompensation in the form of myxedema. A 2-D echocardiogram shows a septal asymmetric hypertrophy, with low-voltage QRS complex in the ECG and a bull's-eye map of longitudinal strain with preserved apical strain with reduction of mid and basal strain that results in "cherry on the top" pattern, similar to the most frequent phenocopy of hypertrophic cardiomyopathy, as is the cardiac amyloidosis, and that, unlike this pathology, reverted after the patient reached the euthyroid state.

Circulating heart failure biomarkers beyond natriuretic peptides: review from the Biomarker Study Group of the Heart Failure Association (HFA), European Society of Cardiology (ESC)

New biomarkers are being evaluated for their ability to advance the management of patients with heart failure. Despite a large pool of interesting candidate biomarkers, besides natriuretic peptides virtually none have succeeded in being applied into the clinical setting. In this review, we examine the most promising emerging candidates for clinical assessment and management of patients with heart failure. We discuss high-sensitivity cardiac troponins (Tn), procalcitonin, novel kidney markers, soluble suppression of tumorigenicity 2 (sST2), galectin-3, growth differentiation factor-15 (GDF-15), cluster of differentiation 146 (CD146), neprilysin, adrenomedullin (ADM), and also discuss proteomics and genetic-based risk scores. We focused on guidance and assistance with daily clinical care decision-making. For each biomarker, analytical considerations are discussed, as well as performance regarding diagnosis and prognosis. Furthermore, we discuss potential implementation in clinical algorithms and in ongoing clinical trials.

Lipoprotein (a) as a treatment target for cardiovascular disease prevention and related therapeutic strategies: a critical overview

Advances in several fields of cardiovascular (CV) medicine have produced new treatments (e.g. to treat dyslipidaemia) that have proven efficacy in terms of reducing deaths and providing a better quality of life. However, the burden of CV disease (CVD) remains high. Thus, there is a need to search for new treatment targets. Lipoprotein (a) [Lp(a)] has emerged as a potential novel target since there is evidence that it contributes to CVD events. In this narrative review, we present the current evidence of the potential causal relationship between Lp(a) and CVD and discuss the likely magnitude of Lp(a) lowering required to produce a clinical benefit. We also consider current and investigational treatments targeting Lp(a), along with the potential cost of these interventions.

Non-Thyroidal Illness Syndrome-Associated Multiorgan Dysfunction After Surgical Repair of Type A Aortic Dissection

OBJECTIVE

The purpose of this cohort study was to investigate the relationship between non-thyroidal illness syndrome (NTIS) and severe multiorgan dysfunction, measured by Sequential Organ Failure Assessment score ≥11, after surgical repair of type A aortic dissection (TAAD).

SETTING

An observational study.

PARTICIPANTS

The present study included 310 patients with TAAD surgically repaired between January 2019 and December 2020 in Beijing Anzhen Hospital.

INTERVENTIONS

Patients after surgical repair after TAAD.

MEASUREMENTS AND MAIN RESULTS

Among a total of 310 patients with TAAD undergoing surgical repair included in this study, 132 (42.6%) experienced surgery-associated NTIS. Severe multiorgan dysfunction was experienced more often in patients with NTIS (27.3% v 11.2%, p < 0.0001). Multivariate analysis demonstrated NTIS was associated closely with an increased risk of severe multiorgan dysfunction (odds ratio [OR] = 2.54, 95% CI = 1.39-4.64 p = 0.002), which predicted an in-hospital death rate of 95%. Non-thyroidal illness syndrome also was related with in-hospital major adverse cardiovascular and cerebral events (OR = 2.12, 95% CI = 1.30-3.46 p = 0.003), acute kidney injury (OR = 3.17, 95% CI = 1.17-8.47 p = 0.023), and postoperative pulmonary complications (OR = 2.32, 95% CI = 1.34-4.03 p = 0.003). However, hepatic inadequacy was comparable in the NTIS and control groups.

CONCLUSIONS

Non-thyroidal illness syndrome was associated closely with multiorgan dysfunction after surgical repair of TAAD, which may be correlated further with an increased incidence of in-hospital mortality and complications.

The Positive Association between Subclinical Hypothyroidism and Newly-Diagnosed Hypertension Is More Explicit in Female Individuals Younger than 65

BACKGROUND

Subclinical hypothyroidism (SCH) is the most common thyroid dysfunction, and its relationship with blood pressure (BP) has been controversial. The aim of the study was to analyze the association between SCH and newly-diagnosed hypertension.

METHODS

Based on data from the Thyroid disease, Iodine nutrition and Diabetes Epidemiology (TIDE) study, 49,433 euthyroid individuals and 7,719 SCH patients aged ≥18 years were enrolled. Patients with a history of hypertension or thyroid disease were excluded. SCH was determined by manufacturer reference range. Overall hypertension and stage 1 and 2 hypertension were diagnosed according to the guidelines issued by the American College of Cardiology/American Heart Association in 2017.

RESULTS

The prevalence of overall hypertension (48.7%), including stage 1 (28.9%) and 2 (19.8%) hypertension, increased significantly in SCH patients compared with euthyroid subjects. With elevated serum thyroid stimulating hormone (TSH) level, the hypertension prevalence also increased significantly from the euthyroid to different SCH subgroups, which was more profound in females or subjects aged <65 years. The age- and sex-specific regression analysis further demonstrated the same trends in the general population and in the 1:1 propensity matched population. Similarly, several BP components (i.e., systolic, diastolic, and mean arterial BP) were positively associated with TSH elevation, and regression analysis also confirmed that all BP components were closely related with SCH in female subjects aged <65 years.

CONCLUSION

The prevalence of hypertension increases for patients with SCH. SCH tends to be associated with hypertension and BP components in females younger than 65 years.

Protective Effects of Thyroid Hormone Deprivation on Progression of Maladaptive Cardiac Hypertrophy and Heart Failure

Purpose: Thyroid hormones (TH) play a central role for cardiac function. TH influence heart rate and cardiac contractility, and altered thyroid function is associated with increased cardiovascular morbidity and mortality. The precise role of TH in onset and progression of heart failure still requires clarification. Methods: Chronic left ventricular pressure overload was induced in mouse hearts by transverse aortic constriction (TAC). One week after TAC, alteration of TH status was induced and the impact on cardiac disease progression was studied longitudinally over 4 weeks in mice with hypo- or hyperthyroidism and was compared to euthyroid TAC controls. Serial assessment was performed for heart function (2D M-mode echocardiography), heart morphology (weight, fibrosis, and cardiomyocyte cross-sectional area), and molecular changes in heart tissues (TH target gene expression, apoptosis, and mTOR activation) at 2 and 4 weeks. Results: In diseased heart, subsequent TH restriction stopped progression of maladaptive cardiac hypertrophy and improved cardiac function. In contrast and compared to euthyroid TAC controls, increased TH availability after TAC propelled maladaptive cardiac growth and development of heart failure. This was accompanied by a rise in cardiomyocyte apoptosis and mTOR pathway activation. Conclusion: This study shows, for the first time, a protective effect of TH deprivation against progression of pathological cardiac hypertrophy and development of congestive heart failure in mice with left ventricular pressure overload. Whether this also applies to the human situation needs to be determined in clinical studies and would infer a critical re-thinking of management of TH status in patients with hypertensive heart disease.

Association between Subclinical Hypothyroidism and Incident Hypertension in Women: A Systematic Review and Meta-Analysis

Subclinical hypothyroidism (SCH) has been found to be associated with an increased risk of cardiovascular diseases. However, there is no clear consensus on the relationship between SCH and hypertension (HTN). We sought to investigate the association between SCH and incident HTN in women. MEDLINE and EMBASE databases were searched for studies that reported the incidence of HTN in females with SCH versus without SCH. Pooled odds ratio (OR) and 95% confidence interval (CI) of the outcome were obtained using a random-effects model. Studies were also divided into the middle-aged (mean age < 65) and the older (mean age ≥ 65) subgroups, and a subgroup analysis was performed to examine the potential age-effect on the association between SCH and HTN. Nine studies with a total of 21,972 subjects met the inclusion criteria. SCH was found to be positively associated with HTN (OR = 1.32, 95% CI = 1.02–1.71). Such association varied depending on the age of women. In the middle-aged subgroup, SCH was more positively associated with HTN (OR = 1.64, 95% CI = 1.18–2.27), while there was no significant association in the older subgroup (OR = 0.97, 95% CI = 0.80–1.16). Our study showed that the middle-aged females with SCH had an increased risk of HTN, while there was no significant association in the older females with SCH.

Increased Epoxyeicosatrienoic Acids and Hydroxyeicosatetraenoic Acids After Treatment of Iodide Intake Adjustment and 1,25-Dihydroxy-Vitamin D3 Supplementation in High Iodide Intake-Induced Hypothyroid Offspring Rats

Aim: This study aimed to investigate the potential role of fatty acids in high iodide intake-induced hypothyroidism and its complications and also in the intervention of iodide intake adjustment and 1,25-dihydroxy-vitamin D3 [1,25(OH)2D3] supplementation. Methods: Pregnant rats were allocated to two groups, namely, normal iodide (NI, 7.5 μg/day) intake and 100 times higher-than-normal iodide (100 HI, 750 μg/day) intake. The offspring were continuously administered potassium iodide from weaning [i.e., postnatal day 21 (PN21)] to PN90. After PN90, the offspring were either administered iodide intake adjustment (7.5 μg/day) or 1,25(OH)2D3 supplementation (5 μg·kg-1·day-1), or both, for 4 weeks. Thyroid function tests (free triiodothyronine, free thyroxine, thyrotropin, thyroid peroxidase antibody, and thyroglobulin antibody), blood lipids (triglyceride, total cholesterol, free fatty acid, and low-density lipoprotein cholesterol), and vitamin D3 (VD3) levels were detected by ELISA. Cardiac function was measured by echocardiography. Blood pressure was measured using a non-invasive tail-cuff system. The serum fatty acids profile was analyzed by liquid chromatography-mass spectrometry. Results: In the offspring rats with continued 100 HI administration, the levels of 8,9-dihydroxyeicosatrienoic acid (8,9-DHET) and thromboxane B2 (TXB2) were decreased, while those of prostaglandin J2 (PGJ2), prostaglandin B2 (PGB2), 4-hydroxydocosahexaenoic acid (4-HDoHE), 7-HDoHE, 8-HDoHE, and 20-HDoHE were increased. Significant correlations were found between PGB2, 8,9-DHET, 7-HDoHE levels and thyroid dysfunction, between PGJ2, 20-HDoHE, PGB2, 8,9-DHET levels and cardiac dysfunction, between PGJ2, 20-HDoHE levels and hypertension, between 4-HDoHE, 8-HDoHE, TXB2 levels and dyslipidemia, and between PGB2 and decreased VD3 level. After the treatment of iodide intake adjustment and 1,25(OH)2D3 supplementation, the levels of 16-hydroxyeicosatetraenoic acids (16-HETE), 18-HETE, 5,6-epoxyeicosatrienoic acid (5,6-EET), 8,9-EET, 11,12-EET, 14,15-EET, PGE2, 5-oxo-ETE, and 15-oxo-ETE were increased. The significant associations between PGE2, 16-HETE, 18-HETE and improved thyroid function and also between 5,6-EET, 11,12-EET, 14,15-EET, 16-HETE, 15-oxo-ETE and attenuated dyslipidemia were detected. Conclusion: Increased levels of prostaglandins (PGs) and HDoHEs and decreased levels of 8,9-DHET and TXB2 might occur in the progression of cardiac dysfunction, hypertension, and dyslipidemia in high iodide intake-induced hypothyroidism. The increased levels of EETs and HETEs might help to ameliorate these complications after iodide intake adjustment and 1,25(OH)2D3 supplementation.

High-Normal Thyroid Function and Recurrence of Atrial Fibrillation after Catheter Ablation: A Prospective Observational Study

BACKGROUND

Thyroid function is increasingly recognized as an important modifiable factor for atrial fibrillation (AF); however, it is unclear if the changes in thyroid hormones, even within the normal range, are associated with AF recurrence after catheter ablation.

METHODS

Consecutive paroxysmal AF patients who underwent catheter ablation were enrolled. Patients with abnormal thyroid hormones or previous thyroid illnesses were excluded. Patients were followed for 12 months or until they presented with the first episode of atrial tachyarrhythmia after a blanking period.

RESULTS

The study included 448 patients with a mean age of 61 (14) years, and 46% were women. After a 1-year follow-up, 104 (23.2%) patients experienced atrial tachyarrhythmia recurrences after an ablation procedure. Recurrence was significantly different among quartile groups of thyroid function, with highest FT4 and FT3 levels associated with the greatest risk of recurrence (p < 0.001 and p = 0.024, respectively). FT4 and FT3 levels were independent predictors of atrial tachyarrhythmia recurrence (hazard ratio 1.07 per 1 pmol/L increase in FT4, 95% confidence interval [CI] 1.01-1.15, p = 0.036 and 1.31 per 1 pmol/L increase in FT3, 95% CI 1.01-1.71, p = 0.032).

CONCLUSIONS

High-normal FT3 and FT4 levels are associated with AF recurrence after catheter ablation in this Chinese population. Attention to thyroid hormones could be valuable to assist in the management of AF.

Boldenone undecylenate disrupts the immune system and induces autoimmune clinical hypothyroidism in rats: Vitamin C ameliorative effects

The present study was designed to evaluate the effects of boldenone undecylenate (BL) abuse alone and in combination with vitamin C (VC) on the immune responses and thyroid structure and function in rats. Thirty adult male Wistar rats were randomly divided into five equal groups and were subjected to various treatment regimens for eight weeks as follows: control group, vehicle control group, VC group orally received VC (120 mg/Kg BW/day), BL-treated group intramuscularly injected with BL (5 mg/kg BW, once/week), and BL+VC group received BL and VC. At the end of this experiment, blood and tissue samples (thyroid, thymus, and spleen) were subjected to hematological evaluation, biochemical analysis, histopathological, and immunohistochemical examinations. In comparison to controls, BL significantly increased the levels of serum proinflammatory interleukins (IL-1 β and IL-6), immunoglobulins (IgG and IgM), and complement 3 but reduced anti-inflammatory interleukin-10, lysosome, and nitric oxide. Besides, altered platelet count and leukogram were evident in BL-injected rats. BL notably disturbed thyroid profile as revealed by a significant increase of thyroid-stimulating hormone and thyroid peroxidase antibody. In contrast, both total and free forms of thyroid hormones (tri-iodothyronine and thyroxine), thyroglobulin, and thyroid peroxidase, were significantly decreased. Moreover, BL caused histopathological changes in the thyroid, thymus, and spleen tissues.CD4⁺ immuno-expression was reduced, but CD8⁺ immunolabelling was increased in both spleen and thymus. The daily dosing of VC to BL-exposed rats significantly corrected most of the deviations in immune parameters. It restored most of the thyroid architecture and function, revealing a significant protective effect of this vitamin. This experimental study demonstrates that BL abusing disrupts the immune system by different mechanisms and addresses BL, for the first time, as an autoimmune clinical hypothyroidism inducer drug. Additionally, VC is helpful in the management of BL abuse.

Climate and air pollution exposure are associated with thyroid function parameters: a retrospective cross-sectional study

OBJECTIVES

There are still controversies about the impact of climatic and environmental factors on thyroid function parameters in healthy populations. We investigated the relationships between climate, air pollution exposure, and thyroid function fluctuations.

METHODS

We retrospectively reviewed 327,913 individuals attending routine health checks from December 2013 to December 2018. We analyzed the associations between thyroid function and climatic factors using Spearman's correlation analysis. We explored the relationships between thyroid function and air pollution exposure using multiple linear regression analysis, after adjusting for age, sex, season, and outdoor temperature. We also performed subgroup analyses by age and sex and sensitivity analyses of different anti-thyroid peroxidase antibody status.

RESULTS

Thyroid-stimulating hormone (TSH) and free triiodothyronine (FT3) were negatively associated with outdoor temperature (r = - 0.66, P < 0.001; r = - 0.55, P < 0.001), while free thyroxine (FT4) and FT4/FT3 were positively associated with temperature (r = 0.35, P < 0.001; r = 0.79, P < 0.001). An increase of 10 μg/m³ in fine particulate matter ≤ 2.5 μm (PM2.5) was associated with a decrease of 0.12 pmol/L in FT4 and an increase of 0.07 pmol/L in FT3 (both P < 0.01). FT4/FT3 was significantly negatively associated with PM2.5 (coefficient: - 0.06, P < 0.01). These results remained robust in hierarchical analyses and sensitivity analyses.

CONCLUSIONS

Thyroid function parameters are associated with climate and air pollution exposure. These factors may influence variations in thyroid function. Our results also highlight the importance of public health interventions to reduce air pollution.

Triiodothyronine maintains cardiac transverse-tubule structure and function

Subclinical hypothyroidism and low T3 syndrome are commonly associated with an increased risk of cardiovascular disease (CVD) and mortality. We examined effects of T3 on T-tubule (TT) structures, Ca²⁺ mobilization and contractility, and clustering of dyadic proteins. Thyroid hormone (TH) deficiency was induced in adult female rats by propyl-thiouracil (PTU; 0.025%) treatment for 8 weeks. Rats were then randomized to continued PTU or triiodo-L-thyronine (T3; 10 μg/kg/d) treatment for 2 weeks (PTU + T3). After in vivo echocardiographic and hemodynamic recordings, cardiomyocytes (CM) were isolated to record Ca²⁺ transients and contractility. TT organization was assessed by confocal microscopy, and STORM images were captured to measure ryanodine receptor (RyR2) cluster number and size, and L-type Ca²⁺ channel (LTCC, Ca_v1.2) co-localization. Expressed genes including two integral TT proteins, junctophilin-2 (Jph-2) and bridging integrator-1 (BIN1), were analyzed in left ventricular (LV) tissues and cultured CM using qPCR and RNA sequencing. The T3 dosage used normalized serum T3, and reversed adverse effects of TH deficiency on in vivo measures of cardiac function. Recordings of isolated CM indicated that T3 increased rates of Ca²⁺ release and re-uptake, resulting in increased velocities of sarcomere shortening and re-lengthening. TT periodicity was significantly decreased, with reduced transverse tubules but increased longitudinal tubules in TH-deficient CMs and LV tissue, and these structures were normalized by T3 treatment. Analysis of STORM data of PTU myocytes showed decreased RyR2 cluster numbers and RyR localizations within each cluster without significant changes in Ca_v1.2 localizations within RyR clusters. T3 treatment normalized RyR2 cluster size and number. qPCR and RNAseq analyses of LV and cultured CM showed that Jph2 expression was T3-responsive, and its increase with treatment may explain improved TT organization and RyR-LTCC coupling.

Serum Free Triiodothyronine and the Responsiveness to Clopidogrel in Patients Undergoing Elective Percutaneous Coronary Intervention

INTRODUCTION

Both thyroid dysfunction and low responsiveness to clopidogrel have been reported to be associated with increased cardiovascular risk. Our study aims at determining the relationship between free triiodothyronine (FT3) and low responsiveness to clopidogrel in patients undergoing elective percutaneous coronary intervention (PCI).

METHODS

Consecutive patients undergoing elective PCI were enrolled. All patients received a loading dose of 300 mg clopidogrel, and platelet function was assessed by thromboelastography at least 12 h later. Low responsiveness to clopidogrel was defined by an adenosine diphosphate-induced platelet-fibrin clot strength > 47 mm and adenosine diphosphate-induced platelet inhibition rate < 50%. Major adverse cardiovascular events (MACEs) were defined as a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and ischemia-driven revascularization.

RESULTS

Of 812 patients included in the study, 289 showed low responsiveness to clopidogrel. The FT3 level was significantly lower in low responders (4.61 ± 0.60 pmol/l versus 4.94 ± 4.66 pmol/l, p = 0.002). Moreover, the percentage of low responders was greater among patients with low FT3 level than among those without (56.1% versus 34.5%, p = 0.007). Logistic regression analysis showed that a FT3 level was independently associated with the risk of low responsiveness to clopidogrel (odds ratio 0.720, 95% confidence interval [CI] 0.533-0.973, p = 0.033). In patients with low responsiveness to clopidogrel, low FT3 was independently associated with increased risk of MACEs (adjusted hazard ratio 3.040, 95% CI 1.077-8.580, p = 0.036) at a median of 19-month follow-up.

CONCLUSIONS

Low FT3 was independently associated with increased risks of both low responsiveness to clopidogrel and cardiovascular events in patients undergoing elective PCI.

Selenium, Selenoproteins, and Heart Failure: Current Knowledge and Future Perspective

PURPOSE OF REVIEW

(Mal-)nutrition of micronutrients, like selenium, has great impact on the human heart and improper micronutrient intake was observed in 30-50% of patients with heart failure. Low selenium levels have been reported in Europe and Asia and thought to be causal for Keshan disease. Selenium is an essential micronutrient that is needed for enzymatic activity of the 25 so-called selenoproteins, which have a broad range of activities. In this review, we aim to summarize the current evidence about selenium in heart failure and to provide insights about the potential mechanisms that can be modulated by selenoproteins.

RECENT FINDINGS

Suboptimal selenium levels (<100 μg/L) are prevalent in more than 70% of patients with heart failure and were associated with lower exercise capacity, lower quality of life, and worse prognosis. Small clinical trials assessing selenium supplementation in patients with HF showed improvement of clinical symptoms (NYHA class), left ventricular ejection fraction, and lipid profile, while governmental interventional programs in endemic areas have significantly decreased the incidence of Keshan disease. In addition, several selenoproteins are found impaired in suboptimal selenium conditions, potentially aggravating underlying mechanisms like oxidative stress, inflammation, and thyroid hormone insufficiency. While the current evidence is not sufficient to advocate selenium supplementation in patients with heart failure, there is a clear need for high level evidence to show whether treatment with selenium has a place in the contemporary treatment of patients with HF to improve meaningful clinical endpoints. Graphical summary summarizing the potential beneficial effects of the various selenoproteins, locally in cardiac tissues and systemically in the rest of the body. In short, several selenoproteins contribute in protecting the integrity of the mitochondria. By doing so, they contribute indirectly to reducing the oxidative stress as well as improving the functionality of immune cells, which are in particular vulnerable to oxidative stress. Several other selenoproteins are directly involved in antioxidative pathways, next to excreting anti-inflammatory effects. Similarly, some selenoproteins are located in the endoplasmic reticulum, playing roles in protein folding. With exception of the protection of the mitochondria and the reduction of oxidative stress, other effects are not yet investigated in cardiac tissues. The systemic effects of selenoproteins might not be limited to these mechanisms, but also may include modulation of endothelial function, protection skeletal muscles, in addition to thyroid metabolism.

ABBREVIATIONS

DIO, iodothyronine deiodinase; GPx, glutathione peroxidase; MsrB2, methionine-R-sulfoxide reductase B2; SELENOK, selenoprotein K; SELENON, selenoprotein N; SELENOP, selenoprotein P; SELENOS, selenoprotein S; SELENOT, selenoprotein T; TXNRD, thioredoxin reductase.

Thyroid disrupting effects of low-dose dibenzothiophene and cadmium in single or concurrent exposure: New evidence from a translational zebrafish model

Thyroid hormones (THs) are major regulators of biological processes essential for correct development and energy homeostasis. Although thyroid disruptors can deeply affect human health, the impact of exogenous chemicals and in particular mixture of chemicals on different aspects of thyroid development and metabolism is not yet fully understood. In this study we have used the highly versatile zebrafish model to assess the thyroid axis disrupting effects of cadmium (Cd) and dibenzothiophene (DBT), two environmental endocrine disruptors found to be significantly correlated in epidemiological co-exposure studies. Zebrafish embryos (5hpf) were exposed to low concentrations of Cd (from 0.05 to 2 μM) and DBT (from 0.05 to 1 μM) and to mixtures of them. A multilevel assessment of the pollutant effects has been obtained by combining in vivo morphological analyses allowed by the use of transgenic fluorescent lines with liquid chromatography mass spectrometry determination of TH levels and quantification of the expression levels of key genes involved in the Hypothalamic-Pituitary-Thyroid Axis (HPTA) and TH metabolism. Our results underscore for the first time an important synergistic toxic effect of these pollutants on embryonic development and thyroid morphology highlighting differences in the mechanisms through which they can adversely impact on multiple physiological processes of the HPTA and TH disposal influencing also heart geometry and function.

Could the level of nitrite/nitrate contribute to malignant thyroid nodule diagnostics?

Thyroid nodules are among highly prevalent thyroid diseases. To make a distinction between benign and malignant thyroid nodules are of cumbersome significance for each endocrinologist. There is no unique and completely accurate diagnostic test, method, or even biomarker that points to a malignant thyroid nodule. Many studies in modern thyroidology are conducted to determine the usefulness of individual biomarkers, which could help clinicians detect thyroid nodules' potential malignant nature. One interesting biomarker with a promising diagnostic potential for the thyroid gland pathological conditions is nitric oxide (NO). Inducible nitric oxide synthase expression is increased in thyroiditis cases and even more in thyroid carcinoma cases, directly connected with increased NO levels in both pathological conditions. We hypothesize that the basal levels of nitrite/nitrate in serum and biopsy washout could indicate nodules' malignant nature.