Lack of canonical thyroid hormone receptor α signaling changes regulatory T cell phenotype in female mice.

The immune system has emerged as an important target of thyroid hormones (THs); however, the role of TH in T cells has so far remained elusive. In this study, we assessed the effect of TH receptor α (TRα) signaling on activation and function of T cells. Our findings show that lack of canonical TRα action not only increased the frequency of regulatory T cells (Treg) but propelled an activated and migratory Treg phenotype and nuclear factor κB (NF-κB) activation in Treg. Conversely, canonical TRα action reduced activation of the NF-κB pathway previously shown to play a pivotal role in Treg differentiation and function. Taken together, our findings demonstrate that TRα impacts T cell differentiation and phenotype. Given the well-known interaction of inflammation, immune responses, and TH axis in e.g., severe illness, altered TH-TRα signaling may have an important role in regulating T cell responses during disease.

Comparative Phenotyping of Mice Reveals Canonical and Noncanonical Physiological Functions of TRα and TRß.

Thyroid hormone (TH) effects are mediated through TH receptors (TRs), TRα1, TRß1, and TRß2. The TRs bind to the DNA and regulate expression of TH target genes (canonical signaling). In addition, they mediate activation of signaling pathways (noncanonical signaling). Whether noncanonical TR action contributes to the spectrum of TH effects is largely unknown. The aim of this study was to attribute physiological effects to the TR isoforms and their canonical and noncanonical signaling. We conducted multiparameter phenotyping in male and female TR knockout mice (TRαKO, TRßKO), mice with disrupted canonical signaling due to mutations in the TR DNA binding domain (TRαGS, TRßGS), and their wild-type littermates. Perturbations in senses, especially hearing (mainly TRß with a lesser impact of TRα), visual acuity, retinal thickness (TRα and TRß), and in muscle metabolism (TRα) highlighted the role of canonical TR action. Strikingly, selective abrogation of canonical TR action often had little phenotypic consequence, suggesting that noncanonical TR action sufficed to maintain the wild-type phenotype for specific effects. For instance, macrocytic anemia, reduced retinal vascularization, or increased anxiety-related behavior were only observed in TRαKO but not TRαGS mice. Noncanonical TRα action improved energy utilization and prevented hyperphagia observed in female TRαKO mice. In summary, by examining the phenotypes of TRα and TRß knockout models alongside their DNA binding-deficient mutants and wild-type counterparts, we could establish that the noncanonical actions of TRα and TRß play a crucial role in modulating sensory, behavioral, and metabolic functions and, thus, contribute to the spectrum of physiological TH effects.

[Endocrine side effects of tumor treatment]. / Endokrine Nebenwirkungen von Tumortherapien.

Targeted and immune-based treatments represent significant innovations in oncology and impressively improve the prognosis of many tumor diseases. Their now widespread use as a standard treatment for several malignant diseases increasingly requires knowledge of how to deal with new adverse events (AE) induced by oncological agents in centers and routine practice [12, 13]. For example, the blockade of specific checkpoints of the inhibitory immune system by immune checkpoint inhibitors (ICI) causes the loss of immune tolerance to the body's own tissue with the occurrence of endocrine immune-related AE (irAE) in approximately 10% of patients treated with ICI [3, 11]. Targeted treatments, such as with tyrosine kinase inhibitors (TKI), mammalian target of rapamycin (mTOR) and phosphoinositide 3­kinase (PI3K) inhibitors often lead to disorders of glucose metabolism and thyroid gland dysfunction. The challenges of maintaining bone health during endocrine therapy in patients with prostate and hormone receptor-positive breast cancer and in the endocrine follow-up care of childhood cancer survivors are well-known and are becoming increasingly more important for the long-term prognosis and quality of life [5, 20]. However, although the recommendations for a systematic management of endocrine side effects of these relatively new tumor therapies can be found in guidelines, they are not yet established in routine clinical care [15, 19]. A close interdisciplinary cooperation is required for optimal care of people with cancer [7]. The development of such interdisciplinary cross-sectoral treatment structures is important as tumor treatment is primarily carried out by hematologists or oncologists, while the management of AE induced by oncological agents increasingly involves primary care physicians including internists and in the case of endocrine AE requires the specific expertise of endocrinologists and diabetologists.

Use of levothyroxine for euthyroid, thyroid antibody positive women with infertility: Analyses of aggregate data from a survey of European thyroid specialists (Treatment of Hypothyroidism in Europe by Specialists: An International Survey).

OBJECTIVES: The use of levothyroxine (LT4) treatment aiming to improve fertility in euthyroid women with positive thyroid peroxidase antibodies (TPOAb) is not supported by the available evidence. The aim of the study was to document the use of LT4 by European thyroid specialists in such patients. DESIGN: The data presented derive from Treatment of Hypothyroidism in Europe by Specialists, an International Survey (THESIS), a questionnaire conducted between 2019 and 2021 to document the management of hypothyroidism by European thyroid specialists. Here, we report the aggregate results on the use of LT4 in infertile, euthyroid women with positive TPOAb. RESULTS: A total of 2316/5406 (42.8%) respondents stated that LT4 may be indicated in TPOAb positive euthyroid women with infertility. The proportion of those replying positively to this question varied widely across different countries (median 39.4, range 22.9%-83.7%). In multivariate analyses males (OR: 0.8; CI: 0.7-0.9) and respondents >60 years (OR: 0.7; 0.6-0.8) were the least inclined to consider LT4 for this indication. Conversely, respondents managing many thyroid patients ("weekly" [OR: 1.4; CI: 1.0-1.9], "daily" [OR: 1.8; CI: 1.3-2.4]) and practicing in Eastern Europe (OR: 1.5; CI: 1.3-1.9) were most likely to consider LT4. CONCLUSIONS: A remarkably high number of respondents surveyed between 2019 and 2021, would consider LT4 treatment in TPOAb positive euthyroid women with infertility. This view varied widely across countries and correlated with sex, age and workload, potentially influencing patient management. These results raise concerns about potential risks of overtreatment.

Canonical and Noncanonical Contribution of Thyroid Hormone Receptor Isoforms Alpha and Beta to Cardiac Hypertrophy and Heart Rate in Male Mice.

Background: Stimulation of ventricular hypertrophy and heart rate are two major cardiac effects of thyroid hormone (TH). The aim of this study was to determine in vivo which TH receptor (TR)-α or ß-and which mode of TR action-canonical gene expression or DNA-binding independent noncanonical action-mediate these effects. Methods: We compared global TRα and TRß knockout mice (TRαKO; TRßKO) with wild-type (WT) mice to determine the TR isoform responsible for T3 effects. The relevance of TR DNA binding was studied in mice with a mutation in the DNA-binding domain that selectively abrogates DNA binding and canonical TR action (TRαGS; TRßGS). Hearts were studied with echocardiography at baseline and after 7 weeks of T3 treatment. Gene expression was measured with real-time polymerase chain reaction. Heart rate was recorded with radiotelemetry transmitters for 7 weeks in untreated, hypothyroid, and T3-treated mice. Results: T3 induced ventricular hypertrophy in WT and TRßKO mice, but not in TRαKO mice. Hypertrophy was also induced in TRαGS mice. Thus, hypertrophy is mostly mediated by noncanonical TRα action. Similarly, repression of Mhy7 occurred in WT and TRαGS mice. Basal heart rate was largely dependent on canonical TRα action. But responsiveness to hypothyroidism and T3 treatment as well as expression of pacemaker gene Hcn2 were still preserved in TRαKO mice, demonstrating that TRß could compensate for absence of TRα. Conclusions: T3-induced cardiac hypertrophy could be attributed to noncanonical TRα action, whereas heart rate regulation was mediated by canonical TRα action. TRß could substitute for canonical but not noncanonical TRα action.

Latest Progress in Risk-Adapted Surgery for Medullary Thyroid Cancer.

(1) Background: The wider adoption of a preoperative ultrasound and calcitonin screening complemented by an intraoperative frozen section has increased the number of patients with occult sporadic medullary thyroid cancer (MTC). These advances offer new opportunities to reduce the extent of the initial operations, minimizing operative morbidity and the risk of postoperative thyroxin supplementation without compromising the cure. (2) Methods: This systematic review of the international literature published in the English language provides a comprehensive update on the latest progress made in the risk-adapted surgery for sporadic and hereditary MTC guided by an intraoperative frozen section. (3) Results: The current evidence confirms the viability of a hemithyroidectomy for desmoplasia-negative sporadic MTC. To add an extra safety margin, the hemithyroidectomy may be complemented by a diagnostic ipsilateral central node dissection. Despite the limited extent of the surgery, all the patients with desmoplasia-negative sporadic tumors achieved a biochemical cure with excellent clinical outcomes. A hemithyroidectomy decreases the need for postoperative thyroxine substitution, but a total thyroidectomy may be required for bilateral nodular thyroid disease. Hereditary MTC is a different issue. Because each residual thyroid C cell carries its own risk of malignant progression, a total thyroidectomy remains mandatory for hereditary MTC. (4) Conclusion: In experienced hands, a hemithyroidectomy, which minimizes morbidity without compromising the cure, is an adequate therapy for desmoplasia-negative sporadic MTC.

Cardiac recovery from pressure overload is not altered by thyroid hormone status in old mice.

Introduction: Thyroid hormones (THs) are known to have various effects on the cardiovascular system. However, the impact of TH levels on preexisting cardiac diseases is still unclear. Pressure overload due to arterial hypertension or aortic stenosis and aging are major risk factors for the development of structural and functional abnormalities and subsequent heart failure. Here, we assessed the sensitivity to altered TH levels in aged mice with maladaptive cardiac hypertrophy and cardiac dysfunction induced by transverse aortic constriction (TAC). Methods: Mice at the age of 12 months underwent TAC and received T4 or anti-thyroid medication in drinking water over the course of 4 weeks after induction of left ventricular pressure overload. Results: T4 excess or deprivation in older mice had no or only very little impact on cardiac function (fractional shortening), cardiac remodeling (cardiac wall thickness, heart weight, cardiomyocyte size, apoptosis, and interstitial fibrosis), and mortality. This is surprising because T4 excess or deprivation had significantly changed the outcome after TAC in young 8-week-old mice. Comparing the gene expression of deiodinases (Dio) 2 and 3 and TH receptor alpha (TRα) 1 and the dominant-negative acting isoform TRα2 between young and aged mice revealed that aged mice exhibited a higher expression of TRα2 and Dio3, while expression of Dio2 was reduced compared with young mice. These changes in Dio2 and 3 expressions might lead to reduced TH availability in the hearts of 12-month-old mice accompanied by reduced TRα action due to higher TRα2. Discussion: In summary, our study shows that low and high TH availability have little impact on cardiac function and remodeling in older mice with preexisting pressure-induced cardiac damage. This observation seems to be the result of an altered expression of deiodinases and TRα isoforms, thus suggesting that even though cardiovascular risk is increasing with age, the response to TH stress may be dampened in certain conditions.

Transition from Paediatric to Adult Care in CAH: 20 Years of Experience at a Tertiary Referral Center.

Transition medicine aims at the coordinated transfer of young patients with a chronic disease from paediatric to adult care. The present study reflects 20 years of experience in transitioning patients with congenital adrenal hyperplasia (CAH) in a single center setting. Our endocrine transition-clinic was established in 2002 and offers joint paediatric and adult consultations. Data were evaluated retrospectively from 2002 to 2005 and 2008 to present. Fifty-nine patients (29 males) were transferred. Median age was 18.4 years (17.6-23.6). Ninety percent of the patients presented with 21-hydroxlase-deficiency (21-OHD), 38 patients (23 m) with salt-wasting (sw), 7 (1 m) with simple-virilising (sv) and 8 (3 m) with the non-classic (nc) form. Rarer enzyme deficiencies were found in 6 cases: 17α-OHD (2 sisters), P450-oxidoreductase-deficiency (2 siblings), 3ß-hydroxysteroid-dehydrogenase-deficiency (1 m) and 11ß-OHD (1 female). Thirty-four patients (57.6%, 20 m) are presently still attending the adult clinic, 1 patient (1.7%, m) moved away and 24 (40.7%, 8 m) were lost to follow-up (13 sw-21-OHD, 6 sv-21-OHD, 5 nc-21-OHD). Thirty-seven patients (62.7%) attended the adult clinic for >2 years after transfer, 17 (28.8%) for >10 years. In the lost to follow-up group, median time of attendance was 16.3 months (0-195.2). Defining a successful transfer as two or more visits in the adult department after initial consultation in the transition clinic, transfer was efficient in 84.7% of the cases. A seamless transfer to adult care is essential for adolescents with CAH. It requires a continuous joint support during the transition period, remains challenging, and necessitates adequate funding.

[Precision medicine in endocrinology exemplified by medullary thyroid cancer]. / Präzisionsmedizin in der Endokrinologie am Beispiel des medullären Schilddrüsenkarzinoms.

Medullary thyroid cancer (MTC) is a prime example for precision medicine in endocrinology and underlines the immediate benefits of basic, translational and healthcare research for patients with a rare disease in clinical . A mutation in the rearranged during transfection (RET) proto-oncogene that codes for a transmembrane receptor protein tyrosine kinase, leads to constitutive activation of the kinase, which is the decisive pathomechanism for the disease. The MTC occurs in a sporadic (somatic RET mutation) or hereditary form (RET germline mutation, multiple endocrine neoplasia types 2 and 3). For germline mutation carriers the timing of preventive thyroidectomy depends on the RET genotype. For advanced metastasized RET-mutant MTC, selective RET kinase inhibitors are available, which are currently considered to be game changers in the treatment. Based on the specific tumor marker calcitonin, MTC can be identified at an early stage during the differential diagnosis of thyroid nodules. The preoperative calcitonin level even enables statements on the degree of dissemination of the disease and on the probability of a cure through surgery. A new development is the consideration of desmoplasia as a histopathological biomarker for the metastatic potential of a MTC, which could possibly modify the operative approach as well as the future MTC nomenclature. Furthermore, the postoperative calcitonin level and the calcitonin doubling time are highly valid prognostic markers for tumor burden and biological aggressiveness of MTC and therefore decisive for patient follow-up. Biochemical, molecular and histological markers enable a risk-adapted surgical treatment and together with new targeted systemic treatments have contributed to a paradigm shift in the diagnostics, prognosis and treatment of MTC in recent years. Endocrine precision medicine for MTC therefore enabled a change from the previous purely symptom-oriented to a modern preventive and individualized treatment.

Risk and Incidence of Endocrine Immune-Related Adverse Effects Under Checkpoint Inhibitor Mono- or Combination Therapy in Solid Tumors: A Meta-Analysis of Randomized Controlled Trials.

CONTEXT: Few meta-analyses on incidence of endocrine immune-related adverse effects (eirAEs) have been published and many trials have been published since. OBJECTIVE: We performed a comprehensive meta-analysis with updated literature to assess risk and incidence of eirAEs of any grade and grade 3 to 5 by immune checkpoint inhibitor (ICI) monotherapy or combination therapy in solid tumors. METHODS: An electronic search using PubMed/Medline, Embase, and the Cochrane Library was performed. Randomized controlled studies (RCTs) assessing eirAEs under ICI monotherapy or ICI combination therapy were selected. Stata software (v17) was used for statistical analyses and risk of bias was evaluated using Review Manager version 5.3. RESULTS: A total of 69 RCTs with 80 independent reports, involving 42 886 patients, were included in the study. Meta-analysis revealed the following pooled estimates for risk ratio and incidence, respectively: for any grade hypothyroidism 7.81 (95% CI, 5.68-10.74, P < .0001) and 7.64% (95% CI, 6.23-9.17, P < .0001); significantly increased also for hyperthyroidism, hypophysitis/hypopituitarism, and adrenal insufficiency; and for insulin-dependent diabetes mellitus 1.52 (95% CI, 1.07-2.18, P = .02), and 0.087% (95% CI, 0.019-0.189, P = .0006), respectively. Meta-regression showed that combination of ICIs (nivolumab plus ipilimumab; durvalumab plus tremelimumab) is an independent risk factor for any grade hypophysitis/hypopituitarism, and that ICI agent is an independent factor of risk for adrenal insufficiency, but that cancer type is not an independent risk factor for eirAEs. CONCLUSION: We showed that risk, independent from cancer type, and incidence of eirAEs are substantially increased with ICI therapy. Combination of ICIs increases risk for eirAEs, especially for hypophysitis/hypopituitarism.