Histological changes in the olfactory bulb and rostral migratory stream due to interruption of olfactory input.

OBJECTIVE: Periglomerular and granule cells in the adult mammalian olfactory bulb modulate olfactory signal transmission. These cells originate from the subventricular zone, migrate to the olfactory bulb via the Rostral Migratory Stream (RMS), and differentiate into mature cells within the olfactory bulb throughout postnatal life. While the regulation of neuroblast development is known to be affected by external stimuli, there is a lack of information concerning changes that occur during the recovery process after injury caused by external stimuli. To address this gap in research, the present study conducted histological observations to investigate changes in the olfactory bulb and RMS occurring after the degeneration and regeneration of olfactory neurons. METHODS: To create a model of olfactory neurodegeneration, adult mice were administered methimazole intraperitoneally. Nasal tissue and whole brains were removed 3, 7, 14 and 28 days after methimazole administration, and EdU was administered 2 and 4 h before removal of these tissues to monitor dividing cells in the RMS. Methimazole-untreated mice were used as controls. Olfactory nerve fibers entering the olfactory glomerulus were observed immunohistochemically using anti-olfactory marker protein. In the brain tissue, the entire RMS was observed and the volume and total number of cells in the RMS were measured. In addition, the number of neuroblasts and dividing neuroblasts passing through the RMS were measured using anti-doublecortin and anti-EdU antibodies, respectively. Statistical analysis was performed using the Tukey test. RESULTS: Olfactory epithelium degenerated was observed after methimazole administration, and recovered after 28 days. In the olfactory glomeruli, degeneration of OMP fibers began after methimazole administration, and after day 14, OMP fibers were reduced or absent by day 28, and overall OMP positive fibers were less than 20%. Glomerular volume tended to decrease after methimazole administration and did not appear to recover, even 28 days after recovery of the olfactory epithelium. In the RMS, EdU-positive cells decreased on day 3 and began to increase on day 7. However, they did not recover to the same levels as the control methimazole-untreated mice even after 28 days. CONCLUSION: These results suggest that the division and maturation of neuroblasts migrating from the RMS was suppressed by olfactory nerve degeneration or the disruption of olfactory input.

Thyroid-Friendly Soft Materials as 3D Cell Culture Tool for Stimulating Thyroid Cell Function.

The disruption of thyroid hormones because of chemical exposure is a significant societal problem. Chemical evaluations of environmental and human health risks are conventionally based on animal experiments. However, owing to recent breakthroughs in biotechnology, the potential toxicity of chemicals can now be evaluated using 3D cell cultures. In this study, the interactive effects of thyroid-friendly soft (TS) microspheres on thyroid cell aggregates are elucidated and their potential as a reliable toxicity assessment tool is evaluated. Using state-of-the-art characterization methods coupled with cell-based analysis and quadrupole time-of-flight mass spectrometry, it is shown that TS-microsphere-integrated thyroid cell aggregates exhibit improved thyroid function. Specifically, the responses of zebrafish embryos, which are used for thyroid toxicity analysis, and the TS-microsphere-integrated cell aggregates to methimazole (MMI), a known thyroid inhibitor, are compared. The results show that the thyroid hormone disruption response of the TS-microsphere-integrated thyroid cell aggregates to MMI is more sensitive compared with those of the zebrafish embryos and conventionally formed cell aggregates. This proof-of-concept approach can be used to control cellular function in the desired direction and hence evaluate thyroid function. Thus, the proposed TS-microsphere-integrated cell aggregates may yield new fundamental insights for advancing in vitro cell-based research.

Comparison of antithyroid effects and hepatic complications of methimazole with catechin and its nanoencapsulation form in adult male rats.

OBJECTIVES: Methimazole is an antithyroid drug and is used clinically in hyperthyroidism. Liver dysfunction is one of the side effects of methimazole. Catechins are natural flavonoids and have antioxidant, antithyroid, and liver protection effects. Despite the wide range of biological properties of catechins, their effective use is limited due to poor water solubility, low stability, and low bioavailability. Catechin niosomal nanoencapsulation improves the properties of catechin and increases its antioxidant activities. METHODS: Niosomal vesicles were synthesized by the Thin Film Hydration method and their physicochemical characteristics, morphology, and percentage of trapped catechin in them were determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), and spectrophotometry, respectively. In this study, 32 adult male rats were divided into 4 groups: control, 50 mg/kg methimazole, 100 mg/kg catechin, and 100 mg/kg nanocapsule niosomal form of catechin. The drugs were administered orally and the duration of treatment was 8 weeks. Then, the serum concentration of thyroid hormones and thyroid stimulating hormone (TSH) by enzyme-linked immunosorbent assay (ELISA) method, and serum liver function tests were performed using an autoanalyzer. The activities of hepatic oxidative enzymes were measured spectrophotometrically. RESULTS: Our study showed that the percentage of catechin encapsulation in the niosome was calculated to be 51%. A significant difference was observed in the catechin and encapsulated catechin treatment groups compared to the methimazole group (p <0.0001). In all three treatment groups of methimazole, catechin, and niosomal nanocapsule catechin, serum levels of TT3, TT4, FT3, FT4, body weight and daily consumption of water and food were significantly reduced compared to the control group (p <0.0001). CONCLUSIONS: The antithyroid effects of catechin and its encapsulated form were comparable to methimazole. Also, the encapsulation improved the hepatoprotective effects of catechin.

Effects of tyrosine kinase inhibitors on androgen, estrogen α, glucocorticoid and thyroid receptors.

Modern anticancer therapies favor a targeted approach. Tyrosine kinase inhibitors (TKIs) are drugs that target molecular pathways involved in various types of malignancies. Although TKIs are safe and well tolerated, they remain not completely selective; e.g., endocrine-mediated adverse events have been observed with their use. In the present study, the effects of seven TKIs were determined on the activities of androgen receptor, estrogen receptor α (ERα), glucocorticoid receptor and thyroid receptor in vitro using stably transfected cell lines expressing firefly luciferase reporter gene: AR-EcoScreen, hERα-HeLa9903, MDA-kb2, and GH3.TRE-Luc cells, respectively. Antiandrogenic activity was seen for erlotinib, estrogenic activity for imatinib, antiestrogenic activity for dasatinib, erlotinib, nilotinib, regorafenib and sorafenib, glucocorticoid activity for erlotinib and ibrutinib, antiglucocorticoid activity for regorafenib and sorafenib, and antithyroid activity for ibrutinib. Additionally, synergism was seen for 1-5 µM dasatinib and 500 nM hydrocortisone combination for glucocorticoid activity in MDA-kb2 cells. The estrogenic activity of imatinib was confirmed as mediated through ERα, and interference of the TKIs with the reporter gene assays was ruled out in a cell-lysate-based firefly luciferase enzyme inhibition assay. Imatinib in combination with 4-hydroxytamoxifen showed concentration-dependent effects on the metabolic activity of ERα-expressing AN3CA, MCF-7, and SKOV3 cells, and on cell proliferation and adhesion of MCF-7 cells. These findings contribute to the understanding of the endocrine effects of TKIs, in terms of toxicity and effectiveness, and define the need to further evaluate the endocrine disrupting activities of TKIs to safeguard human and environmental health.

Hormonal Regulation of the MHC Class I Gene in Thyroid Cells: Role of the Promoter "Tissue-Specific" Region.

In previous studies we have demonstrated that the expression of the Major Histocompatibility Complex (MHC) class I gene in thyrocytes is controlled by several hormones, growth factors, and drugs. These substances mainly act on two regions of the MHC class I promoter a "tissue-specific" region (-800 to -676 bp) and a "hormone/cytokines-sensitive" region (-500 to -68 bp). In a previous study, we have shown that the role of the "tissue-specific" region in the MHC class I gene expression is dominant compared to that of the "hormone/cytokines-sensitive" region. In the present report we further investigate the dominant role of the "tissue-specific" region evaluating the effect of thyroid stimulating hormone (TSH), methimazole (MMI), phenylmethimazole (C10), glucose and thymosin-α1. By performing experiments of electrophoretic mobility shift assays (EMSAs) we show that TSH, MMI and C10, which inhibit MHC class I expression, act on the "tissue-specific" region increasing the formation of a silencer complex. Glucose and thymosin-α1, which stimulate MHC class I expression, act decreasing the formation of this complex. We further show that the silencer complex is formed by two distinct members of the transcription factors families activator protein-1 (AP-1) and nuclear factor-kB (NF-kB), c-jun and p65, respectively. These observations are important in order to understand the regulation of MHC class I gene expression in thyroid cells and its involvement in the development of thyroid autoimmunity.

Ginsenoside Rg3 Alleviates Antithyroid Cancer Drug Vandetanib-Induced QT Interval Prolongation.

Inhibition of human ether-a-go-go-related gene (hERG) potassium channel is responsible for acquired long QT syndromes, which leads to life-threatening cardiac arrhythmia. A multikinase inhibitor, vandetanib, prolongs the progression-free survival time in advanced medullary thyroid cancer. However, vandetanib has been reported to induce significant QT interval prolongation, which limits its clinical application. Some studies have showed that ginsenoside Rg3 decelerated hERG K(+) channel tail current deactivation. Therefore, in this study, we aim to confirm whether ginsenoside Rg3 targeting hERG K(+) channel could be used to reverse the vandetanib-induced QT interval prolongation. Electrocardiogram (ECG) and monophasic action potential (MAP) were recorded using electrophysiology signal sampling and analysis system in Langendorff-perfused rabbit hearts. The current clamp mode of the patch-clamp technique was used to record transmembrane action potential. The whole-cell patch-clamp technique was used to record the hERG K+ current. In Langendorff-perfused hearts, vandetanib prolonged the QT interval in a concentration-dependent manner with an IC50 of 1.96 µmol/L. In human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), vandetanib significantly prolonged the action potential duration at 50%, 70%, and 90% repolarization (APD50, APD70, and APD90). In stable transfected human hERG gene HEK293 cells, vandetanib caused concentrate-dependent inhibition in the step and tail currents of hERG. As expected, ginsenoside Rg3 relieved vandetanib-induced QT interval prolongation in Langendorff-perfused heart and reversed vandetanib-induced APD prolongation in hiPSC-CMs. Furthermore, ginsenoside Rg3 alleviated vandetanib-induced hERG current inhibition and accelerated the process of the channel activation. Ginsenoside Rg3 may be a promising cardioprotective agent against vandetanib-induced QT interval prolongation through targeting hERG channel. These novel findings highlight the therapeutic potential of ginsenoside to prevent vandetanib-induced cardiac arrhythmia.

Probiotic Bifidobacterium longum supplied with methimazole improved the thyroid function of Graves' disease patients through the gut-thyroid axis.

Graves' disease (GD) is an autoimmune disorder that frequently results in hyperthyroidism and other symptoms. Here, we designed a 6-month study with patients divided into three treatment groups, namely, methimazole (MI, n = 8), MI + black bean (n = 9) and MI + probiotic Bifidobacterium longum (n = 9), to evaluate the curative effects of probiotics supplied with MI on thyroid function of patients with GD through clinical index determination and intestinal microbiota metagenomic sequencing. Unsurprisingly, MI intake significantly improved several thyroid indexes but not the most important thyrotropin receptor antibody (TRAb), which is an indicator of the GD recurrence rate. Furthermore, we observed a dramatic response of indigenous microbiota to MI intake, which was reflected in the ecological and evolutionary scale of the intestinal microbiota. In contrast, we did not observe any significant changes in the microbiome in the MI + black bean group. Similarly, the clinical thyroid indexes of patients with GD in the probiotic supplied with MI treatment group continued to improve. Dramatically, the concentration of TRAb recovered to the healthy level. Further mechanistic exploration implied that the consumed probiotic regulated the intestinal microbiota and metabolites. These metabolites impacted neurotransmitter and blood trace elements through the gut-brain axis and gut-thyroid axis, which finally improved the host's thyroid function.

Larval metamorphosis is inhibited by methimazole and propylthiouracil that reveals possible hormonal action in the mussel Mytilus coruscus.

Larval metamorphosis in bivalves is a key event for the larva-to-juvenile transformation. Previously we have identified a thyroid hormone receptor (TR) gene that is crucial for larvae to acquire "competence" for the metamorphic transition in the mussel Mytilus courscus (Mc). The mechanisms of thyroid signaling in bivalves are still largely unknown. In the present study, we molecularly characterized the full-length of two iodothyronine deiodinase genes (McDx and McDy). Phylogenetic analysis revealed that deiodinases of molluscs (McDy, CgDx and CgDy) and vertebrates (D2 and D3) shared a node representing an immediate common ancestor, which resembled vertebrates D1 and might suggest that McDy acquired specialized function from vertebrates D1. Anti-thyroid compounds, methimazole (MMI) and propylthiouracil (PTU), were used to investigate their effects on larval metamorphosis and juvenile development in M. coruscus. Both MMI and PTU significantly reduced larval metamorphosis in response to the metamorphosis inducer epinephrine. MMI led to shell growth retardation in a concentration-dependent manner in juveniles of M. coruscus after 4 weeks of exposure, whereas PTU had no effect on juvenile growth. It is hypothesized that exposure to MMI and PTU reduced the ability of pediveliger larvae for the metamorphic transition to respond to the inducer. The effect of MMI and PTU on larval metamorphosis and development is most likely through a hormonal signal in the mussel M. coruscus, with the implications for exploring the origins and evolution of metamorphosis.

Metabolic effects of brown fat in transitioning from hyperthyroidism to euthyroidism.

OBJECTIVE: Brown adipose tissue (BAT) controls metabolic rate through thermogenesis. As its regulatory factors during the transition from hyperthyroidism to euthyroidism are not well established, our study investigated the relationships between supraclavicular brown adipose tissue (sBAT) activity and physiological/metabolic changes with changes in thyroid status. DESIGN: Participants with newly diagnosed Graves' disease were recruited. A thionamide antithyroid drug (ATD) such as carbimazole (CMZ) or thiamazole (TMZ) was prescribed in every case. All underwent energy expenditure (EE) measurement and supraclavicular infrared thermography (IRT) within a chamber calorimeter, as well as 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomography/magnetic resonance (PET/MR) imaging scanning, with clinical and biochemical parameters measured during hyperthyroidism and repeated in early euthyroidism. PET sBAT mean/maximum standardized uptake value (SUV mean/max), MR supraclavicular fat fraction (sFF) and mean temperature (Tscv) quantified sBAT activity. RESULTS: Twenty-one (16 female/5 male) participants aged 39.5 ± 2.5 years completed the study. The average duration to attain euthyroidism was 28.6 ± 2.3 weeks. Eight participants were BAT-positive while 13 were BAT-negative. sFF increased with euthyroidism (72.3 ± 1.4% to 76.8 ± 1.4%; P < 0.01), but no changes were observed in PET SUV mean and Tscv. Significant changes in serum-free triiodothyronine (FT3) levels were related to BAT status (interaction P value = 0.04). FT3 concentration at hyperthyroid state was positively associated with sBAT PET SUV mean (r = 0.58, P = 0.01) and resting metabolic rate (RMR) (P < 0.01). CONCLUSION: Hyperthyroidism does not consistently lead to a detectable increase in BAT activity. FT3 reduction during the transition to euthyroidism correlated with BAT activity.

The efficiency and safety of methimazole and propylthiouracil in hyperthyroidism: A meta-analysis of randomized controlled trials.

PURPOSE: The aim of this study was to evaluate the efficiency and safety of methimazole (MMI) and propylthiouracil (PTU) in the treatment of hyperthyroidism. METHODS: Articles were searched through the PubMed, EMBASE, Cochrane Library, Web of Science, CNKI, Wanfang, and QVIP. The primary outcomes were clinical efficacy and thyroid hormone levels in MMI and PTU groups. The secondary outcomes were liver function indexes and adverse reactions in MMI and PTU groups. Results were expressed as weighted mean difference (WMD) or odds ratio (OR) with 95% confidence intervals (CIs). The Begg test was applied to assess the publication bias. RESULTS: Totally, 16 randomized controlled trials were retained in this meta-analysis with 973 patients receiving MMI and 933 receiving PTU. The levels of triiodothyronine (T3) (WMD = -1.321, 95% CI: -2.271 to -0.372, P = .006), thyroxine (T4) (WMD = -37.311, 95% CI: -61.012 to -13.610, P = .002), Free T3 (FT3) (WMD = -1.388, 95% CI: -2.543 to -0.233, P = .019), Free T4 (FT4) (WMD = -3.613, 95% CI: -5.972 to -1.255, P = .003), and the risk of liver function damage (OR = 0.208, 95% CI: 0.146-0.296, P < .001) in the MMI group were lower than those in the PTU group. The thyroid-stimulating hormone level (WMD = 0.787, 95% CI: 0.380-1.194, P < .001) and the risk of hypothyroidism (OR = 2.738, 95% CI: 1.444-5.193, P = .002) were higher in the MMI group than those in the PTU group. CONCLUSIONS: Although MMI might have higher risk of hypothyroidism than PTU, the efficacy of MMI may be better than PTU in patients with hyperthyroidism regarding reducing T3, T4, FT3, and FT4 levels, decreasing the risk of liver function damage and increasing the level of thyroid-stimulating hormone. REGISTER NUMBER: osf.io/ds637 (https://osf.io/search/).

Developmental thyroid disruption causes long-term impacts on immune cell function and transcriptional responses to pathogen in a small fish model.

Current evidence suggests thyroid hormones (THs) impact development of the immune system, but few studies have explored the connection between the thyroid and immune systems, especially in fish. This is important as some environmental contaminants disrupt TH homeostasis and may thus have negative impacts on the immune system. To determine the long-term consequences of early life stage (ELS) hypothyroidism on immune function, fathead minnows were exposed to the model thyroid hormone suppressant propylthiouracil (PTU) from < 1 to 30 days post hatch. Fish were transferred to clean water and raised to adulthood (5-7 months post hatch) at which time, several aspects of immune function were evaluated. Ex vivo assessment of immune cell function revealed significant decreases (1.2-fold) in the phagocytic cell activity of PTU-treated fish relative to the controls. Fish were also injected with Yersinia ruckeri to evaluate their in vivo immune responses across a suite of endpoints (i.e., transcriptomic analysis, leukocyte counts, spleen index, hematocrit, bacterial load and pathogen resistance). The transcriptomic response to infection was significantly different between control and PTU-treated fish, though no differences in bacterial load or pathogen resistance were noted. Overall, these results suggest that early life stage TH suppression causes long-term impacts on immune function at the molecular and cellular levels suggesting a key role for TH signaling in normal immune system development. This study lays the foundation for further exploration into thyroid-immune crosstalk in fish. This is noteworthy as disruption of the thyroid system during development, which can occur in response to chemicals present in the environment, may have lasting effects on immune function in adulthood.

Thyroid hormones during the perinatal period are necessary to respiratory network development of newborn rats.

Thyroid hormones (THs) are essential for foetal brain development. Because the gestating mother is the main source of THs to the foetus, maternal hypothyroidism and/or premature birth compromise neurological outcomes in the offspring. Respiratory instability and recurrent apneas due to immaturity of the respiratory control network are major causes of morbidity in infants. Inadequate TH supply may be sufficient to delay perinatal maturation of the respiratory control system; however, this hypothesis remains untested. To address this issue, maternal hypothyroidism was induced by adding methimazole (MMI; 0.02% w/v) to the drinking water of pregnant dams from conception to postpartum day 4 (P4). The effect of TH supplementation on respiratory function was tested by injecting levothyroxine (L-T4) in newborns at P1. Respiratory function was assessed by plethysmography (in vivo) and recording of phrenic output from medullary preparations (in vitro). By comparison with controls, TH deficiency increased the frequency of apneas and decreased basal ventilation in vivo and prevented the age-dependent increase in phrenic burst frequency normally observed in vitro. The effects of TH deficiency on GABAergic modulation of respiratory activity were measured by bath application of muscimol (GABAA agonist) or bicuculline (GABAA antagonist). The phrenic burst frequency responses to GABAergic agents were consistently greater in preparations from TH deficient pups. L-T4 supplementation reversed part of the respiratory anomalies related to MMI treatment in vitro. We conclude that TH deficiency during the perinatal period is sufficient to delay maturation of the respiratory control network development. Excessive GABAergic inhibition may contribute to this effect.

Novel presentation of the c.1856A > G (p.Asp619Gly) TSHR gene-activating variant: relapsing hyperthyroidism in three subsequent generations manifesting in early childhood and an in vitro functional study.

BACKGROUND: Familial non-autoimmune hyperthyroidism is a rare disease caused by germline activating variants in the thyroid-stimulating hormone receptor (TSHR) gene. The c.1856A > G (p.Asp619Gly) pathogenic variant has been described in cases of toxic adenoma but never before, to our knowledge, in a case of familial non-autoimmune hyperthyroidism. PATIENT FINDINGS: A 3-year-old boy was admitted for acute gastroenteritis presenting with goiter and tall stature. Laboratory findings revealed peripheral hyperthyroidism and negativity for thyroid autoantibodies. Antithyroid drug treatment was effective, but relapses occurred shortly after attempts to decrease the drug dose. As the boy's father and paternal grandmother also experienced relapsing hyperthyroidism manifesting in early childhood, genetic testing of TSHR was indicated. The c.1856A > G (p.Asp619Gly) pathogenic variant was found in all three affected family members. Functional in vitro characterization of the variant verified that it enhances constitutional activation of the receptor, leading to increased production of cyclic adenosine monophosphate. Total thyroidectomy was indicated in the boy due to an unsatisfactory prognosis. Due to persistent positive thyroglobulin serum concentration, a diagnostic radioiodine scan was performed approximately 2 years later. Residual thyroid tissue was revealed; therefore, radioiodine ablative therapy was performed. Despite adequate thyroxine substitution over a long period of follow-up, TSH remained suppressed. CONCLUSIONS: Unlike Graves' disease, familial non-autoimmune hyperthyroidism cases present with antithyroid drug-dependence. Not ultrasound but positive thyroglobulin serum concentration indicated residual thyroid tissue. Early detection of residual thyroid tissue and radioiodine ablation prevented the subject from experiencing relapsing hyperthyroidism and undergoing unnecessary repeated surgery. Life-long hormone substitution should be adjusted to free thyroxine rather than TSH serum concentrations.

Breathing-driven prefrontal oscillations regulate maintenance of conditioned-fear evoked freezing independently of initiation.

Brain-body interactions are thought to be essential in emotions but their physiological basis remains poorly understood. In mice, regular 4 Hz breathing appears during freezing after cue-fear conditioning. Here we show that the olfactory bulb (OB) transmits this rhythm to the dorsomedial prefrontal cortex (dmPFC) where it organizes neural activity. Reduction of the respiratory-related 4 Hz oscillation, via bulbectomy or optogenetic perturbation of the OB, reduces freezing. Behavioural modelling shows that this is due to a specific reduction in freezing maintenance without impacting its initiation, thus dissociating these two phenomena. dmPFC LFP and firing patterns support the region's specific function in freezing maintenance. In particular, population analysis reveals that network activity tracks 4 Hz power dynamics during freezing and reaches a stable state at 4 Hz peak that lasts until freezing termination. These results provide a potential mechanism and a functional role for bodily feedback in emotions and therefore shed light on the historical James-Cannon debate.

Effects of thyroxine and propylthiouracil on feeding behavior and the expression of hypothalamic appetite-regulating peptides and thyroid function in goldfish (Carassius auratus).

There is poor evidence for an association between thyroidal state, feeding and appetite regulation in fish. We assessed how an altered thyroid state influences feeding behavior, food intake and expression of hypothalamic appetite-regulating peptides (Klotho-α and Klotho-ß; orexin, OX; cholecystokinin, CCK; agouti-related peptide, AgRP; cannabinoid receptor 1, CB1) in goldfish. We also measured the expressions of hypothalamic, pituitary and liver transcripts that regulate the thyroid [thyrotropin-releasing hormone (TRH), thyrotropin-releasing hormone receptor (TRH-R) type 1, thyroid stimulating hormone beta (TSHß), deiodinases (DIO2, DIO3), UDP-glucuronosyltransferase (UGT1A1), thyroid receptor alpha and beta (TRα, TRß)], and circulating levels of total thyroxine (tT4) and total triiodothyronine (tT3). Goldfish were implanted with propylthiouracil (PTU) or T4 osmotic pumps for 12 days. T4- treatment increased feeding behavior but not food intake, increased central TSHß and DIO2, and hepatic DIO2 transcript expression and increased central DIO3 mRNA. Under hyperthyroid conditions, hypothalamic Klotho and CCK expressions were downregulated, suggesting an increased metabolic state and a hypothalamic response to regulate energy balance. AgRP, OX and CB1 were not affected by T4 treatment. PTU had no effect on any of the parameters examined, suggesting it is not a sensitive thyroid inhibitor in fish. Overall, we show that unlike in mammals, hyperthyroid conditions in goldfish do not lead to an increased desire or need to consume food, furthering evidence for a weak link between the thyroid and appetite.

RBM20-Mediated Pre-mRNA Splicing Has Muscle-Specificity and Differential Hormonal Responses between Muscles and in Muscle Cell Cultures.

Pre-mRNA splicing plays an important role in muscle function and diseases. The RNA binding motif 20 (RBM20) is a splicing factor that is predominantly expressed in muscle tissues and primarily regulates pre-mRNA splicing of Ttn, encoding a giant muscle protein titin that is responsible for muscle function and diseases. RBM20-mediated Ttn splicing has been mostly studied in heart muscle, but not in skeletal muscle. In this study, we investigated splicing specificity in different muscle types in Rbm20 knockout rats and hormonal effects on RBM20-mediated splicing both in cellulo and in vivo studies. The results revealed that RBM20 is differentially expressed across muscles and RBM20-mediated splicing is muscle-type specific. In the presence of RBM20, Ttn splicing responds to hormones in a muscle-type dependent manner, while in the absence of RBM20, Ttn splicing is not affected by hormones. In differentiated and undifferentiated C2C12 cells, RBM20-mediated splicing in response to hormonal effects is mainly through genomic signaling pathway. The knowledge gained from this study may help further understand muscle-specific gene splicing in response to hormone stimuli in different muscle types.

Decreased Treg Cell and TCR Expansion Are Involved in Long-Lasting Graves' Disease.

Graves' disease (GD) is a T cell-mediated organ-specific autoimmune disorder. GD patients who have taken anti-thyroid drugs (ATDs) for more than 5 years with positive anti-thyroid stimulating hormone receptor autoantibodies value were defined as persistent GD (pGD). To develop novel immunotherapies for pGD, we investigated the role of T cells in the long-lasting phase of GD. Clinical characteristics were compared between the pGD and newly diagnosed GD (nGD) (N = 20 respectively). Flow cytometric analysis was utilized to determine the proportions of Treg and Th17 cells (pGD, N = 12; nGD, N = 14). T cell receptor sequencing (TCR-seq) and RNA sequencing (RNA-seq) were also performed (pGD, N = 13; nGD, N = 20). Flow cytometric analysis identified lower proportions of Th17 and Treg cells in pGD than in nGD (P = 0.0306 and P = 0.0223). TCR-seq analysis revealed a lower diversity (P = 0.0025) in pGD. Specifically, marked clonal expansion, represented by an increased percentage of top V-J recombination, was observed in pGD patients. Interestingly, pGD patients showed more public T cell clonotypes than nGD patients (2,741 versus 966). Meanwhile, RNA-seq analysis revealed upregulation of the inflammation and chemotaxis pathways in pGD. Specifically, the expression of pro-inflammatory and chemotactic genes (IL1B, IL13, IL8, and CCL4) was increased in pGD, whereas Th17 and Treg cells associated genes (RORC, CARD9, STAT5A, and SATB1) decreased in pGD. Additionally, TCR diversity was negatively correlated with the expression of pro-inflammatory or chemotactic genes (FASLG, IL18R1, CCL24, and CCL14). These results indicated that Treg dysregulation and the expansion of pathogenic T cell clones might be involved in the long-lasting phase of GD via upregulating chemotaxis or inflammation response. To improve the treatment of pGD patients, ATDs combined therapies, especially those aimed at improving Treg cell frequencies or targeting specific expanded pathogenic TCR clones, are worth exploring in the future.

Graves' orbitopathy: a multidisciplinary approach.

Orbitopathy is the main extra thyroidal manifestation of Graves' disease. It is a very challenging condition, which requires a cooperation between many specialists (endocrinologists, ophthalmologists, radiologists, radiotherapeutic, orbital surgeons) for an optimal clinical management. An accurate diagnostic assessment is required, in order to plan an adequate treatment of Graves' orbitopathy. Medical therapy, radiotherapy or surgery may be necessary to control the disease. In this review, the authors analyze the various therapeutic strategies, as well the more recent therapies based on pharmacologic immunomodulation.

Radioiodine therapy of thyroid autonomy.

Radioiodine therapy (RIT) of thyroid functional autonomy (TFA) is rapidly evolving, though it has been recognized for decades as a very effective treatment of toxic nodular varieties. Indeed, TFA is a frequent cause of persistent subclinical hyperthyroidism, which should be regarded as a new metabolic syndrome, with well-established adverse cardio-vascular consequences. Sensitive TSH assays and multiparametric ultrasounds are not accurate enough to reliably diagnose TFA and identify its main variants, unifocal, multifocal (UFA/MFA) and disseminated autonomy (DISA). Modern diagnostic tools are extensively presented and rely upon Thyroid Scan imaging and quantification. A new relationship allows predicting at baseline, an excess of 123I uptake as compared to the TSH stimulation in compensated TFA. Suppressed TS are useful with either isotope, otherwise. Diagnosis of the DISA variant is presented as compared to Graves' disease. Dosimetry has some specificity in TFA work-up. Indeed, the spatial distribution of the dose is as important as the mean value itself and can be eventually controlled by adjusting the TSH level with the smart use of LT3 or antithyroid drug therapy (ATD). A review of the different ways to determine the target mass from anatomical to functional approaches is presented. Main clinical and dosimetric published results of RIT are summarized according to clinical goals. Endogenous TSH stimulation using an ATD preparation has promising results in reducing big autonomously functioning goiters. Finally, we report preliminary successful results of preventive RIT using short term LT3 suppression in compensated TFA, with low administered activities and low rate of hypothyroidism.

The role of laboratory medicine in the diagnosis of the hyperthyroidism.

Hyperthyroidism is a clinical condition characterized by inappropriately high synthesis and secretion of thyroid hormones by the thyroid gland. It has multiple aetiologies, manifestations and potential therapies. Graves' disease is the most common form of hyperthyroidism, due to the production of autoantibodies against thyrotropin receptor, capable of over-stimulating thyroid function. A reliable diagnosis of hyperthyroidism can be established on clinical grounds, followed by the evaluation of serum thyroid function tests (thyrotropin first and then free thyroxine, adding the measurement of free triiodothyronine in selected specific situations). The recent guidelines of both the American and European Thyroid Associations have strongly recommended the measurement of thyrotropin receptor autoantibodies for the accurate diagnosis and management of Graves' disease. If autoantibody test is negative, a radioiodine uptake should be performed. Considering the most recent laboratory improvements, binding assays can be considered the best first solution for the measurement of thyrotropin receptor autoantibodies in diagnosis and management of overt cases of Graves' disease. In fact, they have a satisfactory clinical sensitivity and specificity (97.4% and 99.2%, respectively) being performed in clinical laboratories on automated platforms together with the other thyroid function tests. In this setting, the bioassays should be reserved for fine and complex diagnoses and for particular clinical conditions where it is essential to document the transition from stimulating to blocking activity or vice versa (e.g. pregnancy and post-partum, related thyroid eye disease, Hashimoto's thyroiditis with extrathyroidal manifestations, unusual cases after LT4 therapy for hypothyroidism or after antithyroid drug treatment for Graves' disease). Undoubtedly, technological advances will help improve laboratory diagnostics of hyperthyroidism. Nevertheless, despite future progress, the dialogue between clinicians and laboratory will continue to be crucial for an adequate knowledge and interpretation of the laboratory tests and, therefore, for an accurate diagnosis and correct management of the patient.