Changes in brain structure in subjects with resistance to thyroid hormone due to THRB mutations

BACKGROUND

Being critical for brain development and neurocognitive function thyroid hormones may have an effect on behaviour and brain structure. Our exploratory study aimed to delineate the influence of mutations in the thyroid hormone receptor (TR) ß gene on brain structure.

METHODS

High-resolution 3D T1-weighted images were acquired in 21 patients with a resistance to thyroid hormone ß (RTHß) in comparison to 21 healthy matched-controls. Changes in grey and white matter, as well as cortical thickness were evaluated using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI).

RESULTS

RTHß patients showed elevated circulating fT4 & fT3 with normal TSH concentrations, whereas controls showed normal thyroid hormone levels. RTHß patients revealed significantly higher scores in a self-rating questionnaire for attention deficit hyperactivity disorder (ADHD). Imaging revealed alterations of the corticospinal tract, increased cortical thickness in bilateral superior parietal cortex and decreased grey matter volume in bilateral inferior temporal cortex and thalamus.

CONCLUSION

RTHb patients exhibited structural changes in multiple brain areas. Whether these structural changes are causally linked to the abnormal behavioral profile of RTHß which is similar to ADHD, remains to be determined.

Not Simply a Structural Problem: Psychological Determinants of Headache in Patients with Tumors of the Sellar Region

OBJECTIVE

Headache in patients with tumors of the sellar region (TSR) has previously been attributed entirely to biomechanical causes. This study aimed to investigate the influence of psychological determinants for the occurrence of and disability due to headaches in patients with TSR.

METHODS

This was a cross-sectional single-center study with a logistic regression approach. Eighty-four patients (75%) with pituitary adenomas and 28 with other TSR prior to first-time neurosurgery were investigated. One-hundred and twelve patients received standardized questionnaires on personality, headache characteristics, and disability due to headache. Fifty-nine patients additionally filled in questionnaires about coping with stress and pain catastrophizing. Separate logistic regression models were used to predict the risk of headache occurrence and disability due to headache by personality, stress coping, and pain catastrophizing.

RESULTS

Conscientiousness, neuroticism, and pain catastrophizing were significant predictors of headache occurrence. The amount of explained variance for both models predicting headache occurrence was comparable to that in primary headache. Neuroticism, pain catastrophizing, and humor as a coping strategy predicted disability due to headache with a high variance explanation of 20-40%.

CONCLUSION

For the first time, we report data supporting a strong psychological influence on headache and headache-related disability in patients with TSR, which argue against purely mechanistic explanatory models. Physicians treating patients with TSR and headaches should adopt an integrative diagnostic and treatment approach, taking the biopsychosocial model of pain into account.

Malignancy rates in thyroid nodules: a long-term cohort study of 17,592 patients

Objectives

Ultrasound diagnosis of thyroid nodules has greatly increased their detection rate. Their risk for malignancy is estimated between 7 and 15% in data from specialized centers which are used for guidelines recommendations. This high rate causes considerable anxiety to patients upon first diagnosis. Here, we retrospectively analyzed the malignancy rate of sonographically diagnosed nodules larger than 1 cm from a primary/secondary care center when long-term longitudinal follow-up was included.

Patients/methods

In the study, 17,592 patients were diagnosed with a thyroid nodule larger than 1 cm, of whom 7776 were assessed by fine-needle aspiration cytology (FNAC) and 9816 by sonography alone. 9568 patients were initially discharged due to innocent results of FNAC and/or ultrasound. In 1904 patients, definitive histology was obtained, and 6731 cases were included in the long-term follow-up (up to 23 years, median 5 years).

Results

Malignancy was histologically confirmed in 189 patients (1.1% of all) when excluding accidentally diagnosed papillary microcarcinomas. 155 were diagnosed during the first year of management, 25 in years 2-5 of follow-up, 9 in years 6-10 and nil in 1165 patients followed beyond 10 years.

Conclusions

The malignancy rate of thyroid nodules from primary/secondary care was much lower than that previously reported. During follow-up for more than 5 years, their rate rapidly dropped to less than 1/1000 cases. This low malignancy rate may help to reassure patients first confronted with the diagnosis of a thyroid nodule, substantially reduce their anxiety and avoid unwarranted diagnostic and therapeutic procedures.

Reduced pituitary size in subjects with mutations in the THRB gene and thyroid hormone resistance

BACKGROUND

Thyroid hormone action is mediated by two forms of thyroid hormone receptors (α, β) with differential tissue distribution. Thyroid hormone receptor β (TRβ) mutations lead to resistance to thyroid hormone action in tissues predominantly expressing the β form of the receptor (pituitary, liver). This study seeks to identify the effects of mutant TRβ on pituitary size.

METHODS

High-resolution 3D T1-weighted magnetic resonance images were acquired in 19 patients with RTHβ in comparison to 19 healthy matched controls. Volumetric measurements of the pituitary gland were performed independently and blinded by four different raters (two neuroradiologists, one neurologist, one neuroscientist).

RESULTS

Patients with mutant TRβ (resistance to thyroid hormone β, RTHβ) showed elevated free tri-iodothyronine/thyroxine levels with normal thyroid-stimulating hormone levels, whereas healthy controls showed normal thyroid hormone levels. Imaging revealed smaller pituitary size in RTHβ patients in comparison to healthy controls (F(1,35) = 7.05, P = 0.012, partial η2 = 0.17).

CONCLUSION

RTHβ subjects have impaired sensitivity to thyroid hormones, along with decreased size of the pituitary gland.

Clinical Experience of the Efficacy and Safety of Low-dose Tolvaptan Therapy in a UK Tertiary Oncology Setting

CONTEXT

In patients with cancer, hyponatremia is associated with increased morbidity and mortality and can delay systemic therapy.

OBJECTIVE

To assess the safety and efficacy of low-dose tolvaptan (7.5 mg) for hospitalized, adult patients with hyponatremia due to syndrome of inappropriate antidiuresis (SIAD), and coexisting malignancy.

METHODS

Retrospective evaluation in a tertiary cancer center.

RESULTS

Fifty-five patients with mean baseline serum sodium (sNa) 117.9 ± 4.6 mmol/L were included. In total, 90.9% had severe hyponatremia (sNa < 125 mmol/L). Mean age was 65.1 ± 9.3 years. Following an initial dose of tolvaptan 7.5 mg, median (range) increase in sNa observed at 24 hours was 9 (1-19) mmol/L. Within 1 week, 39 patients (70.9%) reached sNa ≥ 130 mmol/L and 48 (87.3%) had sNa rise of ≥5 mmol/L within 48 hours. No severe adverse events were reported. Thirty-three (60%) and 17 (30.9%) patients experienced sNa rise of ≥8 and ≥12 mmol/L/24 hours, respectively. The rate of sNa correction in the first 24 hours was significantly higher among participants that continued fluid restriction after tolvaptan administration (median [quantiles]: 14 [9-16] versus 8 [5-11] mmol/L, P = .036). Moreover, in the over-rapid correction cohort (≥12 mmol/L/24 hours) demeclocycline was appropriately discontinued only in 60% compared with 91.7% of the remaining participants (P = .047). Lower creatinine was predictive of higher sNa correction rate within 24 hours (P = .01).

CONCLUSION

In the largest series to date, although low-dose tolvaptan was demonstrated to be effective in correcting hyponatremia due to SIAD in cancer patients, a significant proportion experienced over-rapid correction. Concurrent administration of demeclocycline and/or fluid restriction must be avoided due to the increased risk of over-rapid correction.

Single Nucleotide Polymorphisms in Thyroid Hormone Transporter Genes MCT8, MCT10 and Deiodinase DIO2 Contribute to Inter-Individual Variance of Executive Functions and Personality Traits

Thyroid hormones are modulators of cognitive functions, and changes in hormone levels affect intelligence, memory, attention and executive function. Single nucleotide polymorphisms (SNPs) of transporter proteins MCT8, MCT10 and deiodinase 2 (DIO2) influence thyroid metabolism and could therefore contribute to inter-individual variance of cognitive functions. This study investigates the influence of these SNPs using an extensive neuropsychological test battery. 656 healthy participants aged 18-39 years were genotyped for four SNPs: MCT8 (rs5937843 and rs6647476), MCT10 (rs14399) and DIO2 (rs225014) and underwent eleven different neuropsychological tests as well as four personality questionnaires. Test results were compared between homo- and heterozygous carriers and for the X-linked MCT8 additionally between men and women. Personality questionnaires revealed that Risk Seeking was reduced in homozygous T carriers and highest in homozygous C carriers of the DIO2 SNP and that both polymorphisms of MCT8 had an additive effect on Physical Aggression in men. Neuropsychological testing indicated that MCT10 affects nonverbal reasoning abilities, DIO2 influences working memory and verbal fluency and MCT8 influences attention, alertness and planning. This pilot study suggests an influence of polymorphisms in thyroid hormone transporter genes and deiodinase on cognitive domains and personality traits.

Screening for New Markers to Assess Thyroid Hormone Action by OMICs Analysis of Human Samples

Determination of the levels of thyroid-stimulating hormone (TSH) and free thyroid hormones (fTHs) is crucial for assessing thyroid function. However, as a result of inter-individual genetic variability and different environmental factors individual set points exist for TSH and fTHs and display considerable variation. Furthermore, under specific pathophysiological conditions like central hypothyroidism, TSH secreting pituitary tumors, or thyroid hormone resistance the established markers TSH and fTH fail to reliably predict thyroid function and adequate supply of TH to peripheral organs. Even in case of overt hyper- and hypothyroidism circulating fTH concentrations do not correlate with clinical symptoms. Therefore, there is a clear need for novel, more specific biomarkers to diagnose and monitor thyroid function. OMICs screening approaches allow parallel profiling of hundreds to thousands of molecules and thus comprehensive monitoring of molecular alterations in tissues and body fluids that might be associated with changes in thyroid function. These techniques thus constitute promising tools for the identification of urgently needed novel biomarkers. This mini review summarizes the findings of OMICs studies in thyroid research with a particular focus on population-based and patient studies as well as interventional approaches investigating the effects of thyroid hormone administration.

CD5L Constitutes a Novel Biomarker for Integrated Hepatic Thyroid Hormone Action

Background: Pathological conditions of the thyroid hormone (TH) system are routinely diagnosed by using serum concentrations of thyrotropin (TSH), which is sufficient in most cases. However, in certain conditions, such as resistance to TH due to mutations in THRB (RTHb) or TSH-releasing pituitary adenoma (TSHoma), TSH may be insufficient for a correct diagnosis, even in combination with serum TH concentrations. Likewise, under TH replacement therapy, these parameters can be misleading and do not always allow optimal treatment. Hence, additional biomarkers to assess challenging clinical conditions would be highly beneficial. Methods: Data from untargeted multi-omics analyses of plasma samples from experimental thyrotoxicosis in human and mouse were exploited to identify proteins that might represent possible biomarkers of TH function. Subsequent mouse studies were used to identify the tissue of origin and the involvement of the two different TH receptors (TR). For in-depth characterization of the underlying cellular mechanisms, primary mouse cells were used. Results: The analysis of the plasma proteome data sets revealed 16 plasma proteins that were concordantly differentially abundant under thyroxine treatment compared with euthyroid controls across the two species. These originated predominantly from liver, spleen, and bone. Independent studies in a clinical cohort and different mouse models identified CD5L as the most robust putative biomarker under different serum TH states and treatment periods. In vitro studies revealed that CD5L originates from proinflammatory M1 macrophages, which are similar to liver-residing Kupffer cells, and is regulated by an indirect mechanism requiring the secretion of a yet unknown factor from hepatocytes. In agreement with the role of TRα1 in immune cells and the TRβ-dependent hepatocyte-derived signaling, the in vivo regulation of Cd5l expression depended on both TR isoforms. Conclusion: Our results identify several novel targets of TH action in serum, with CD5L as the most robust marker. Although further studies will be needed to validate the specificity of these targets, CD5L seems to be a promising candidate to assess TH action in hepatocyte-macrophage crosstalk.

[Thyroid hormone therapy in old age]

BACKGROUND

There is evidence that the treatment of overt hyperthyroidism with thyroid hormones is able to reduce mortality as well as cardiovascular and musculoskeletal morbidity. It remains unclear whether these data can be extrapolated to the mildest form of hypothyroidism, subclinical hypothyroidism. Furthermore, it is uncertain whether and to what extent the threshold for therapeutic intervention needs to be modified in the elderly, in whom hypothalamo-pituitary regulation is increasingly insensitive to the negative feedback by thyroid hormones and the patients' response to thyroid hormones changes.

OBJECTIVE

The aim of this review is to evaluate the current evidence on the treatment of hypothyroidism in old age with regard to the initiation of therapy and the therapeutic goals.

RESULTS AND CONCLUSIONS

According to new original data and meta-analyses, therapy with thyroid hormones does not alter morbidity and mortality in patients with subclinical hypothyroidism with thyroid stimulating hormone (TSH) below the range of 7-10 mU/l. These data support the TSH threshold of 10 mU/l recommended in guidelines, particularly in elderly patients over the age of 65 years, in whom TSH serum levels increase with age. In contrast to the recommendations, the prescription of thyroxine more than doubled in a large study from Denmark and TSH levels decreased from 10 mU/l to under 7 mU/l between 2001 and 2015. As (the primarily unspecific) symptoms and quality of life are not altered by thyroxine replacement in studies on subclinical hypothyroidism and elderly patients are more susceptible to side effects, thyroid hormone substitution should generally not be started at TSH levels <10 mU/l.

[Hypoparathyroidism - un underestimated problem?]

BACKGROUND

Hypoparathyroidism is a rare and disabilitating disorder characterized by hypocalcemia and low parathyroid hormone levels. Most of the cases occur as a result of the removal of parathyroid glands or damage to the glands during neck surgery. More rare causes include nonsurgical causes such as autoimmune or genetic diseases.

METHOD

In this review, a panel of experts presents the current state of diagnosis and therapy of hypoparathyroidism and explains practical aspects of caring for the affected patients.

RESULTS

Common signs and symptoms are abnormal sensations and increased excitability in the lower limbs, paresthesia of perioral areas and nocturnal leg cramps. Renal complications frequently occur, but also basal ganglia calcification. Treatment consists of administration of vitamin D analogs in combination with 0.5-1.0 g calcium daily. An adjunctive treatment with the in April 2017 approved recombinant human parathyroid hormone (1-84) is an option for patients whose hypoparathyroidism is difficult to control by conventional treatment alone. Initially and after dose changes follow-up controls should be performed at least every 2 weeks, in well-controlled patients or in the case of chronic progression every 3-6 months.

Patients with mutations of the Thyroid hormone beta-receptor show an ADHD-like phenotype for performance monitoring: an electrophysiological study

•

Mutations in the thyroid hormone receptor beta (THRB) lead to relative hyperthyroidism in the brain.

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Electrophysiological biomarkers of performance monitoring (ERN and Pe components) show a pattern similar to ADHD in carriers of THRB mutations.

•

The phenotype of THRB mutation carriers is indistinguishable from ADHD with regard to performance monitoring.

Resistance to thyroid hormone beta (RTHβ) is a syndrome of reduced responsiveness of peripheral tissue to thyroid hormone, caused by mutations in the thyroid hormone receptor beta (THRB). Its cognitive phenotype has been reported to be similar to attention deficit hyperactivity disorder (ADHD). This study used electrophysiological biomarkers of performance monitoring in RTHβ to contribute further evidence on its phenotypical similarity to ADHD. Twenty-one participants with RTHβ aged 18–67 years and 21 matched healthy controls performed a modified flanker task during EEG recording. The RTHβ and control groups were compared on behavioural measures and components of event related potentials (ERPs), i.e. the error related negativity (ERN), the error positivity (Pe) and P3 component. There were no significant group differences with regard to behaviour. RTHβ subjects displayed significantly reduced ERN and Pe amplitudes compared to the controls in the response-locked ERPs. In addition, we observed reduced P3 amplitudes in both congruent and incongruent trials, as well as prolonged P3 latencies in RTHβ subjects in the stimulus-locked ERPs. Our findings reveal alterations in error detection and performance monitoring of RTHβ patients, likely indicating reduced error awareness. The electrophysiological phenotype of RTHß subjects with regard to action monitoring is indistinguishable from ADHD.

The Influence of Thyroid Hormones on Brain Structure and Function in Humans

The pleiotropic function of thyroid hormones (TH) is mediated by an organ specific expression of thyroid hormone transporters, deiodinases and TH receptors. In a series of studies we used the model of an experimentally induced hyper- or hypothyroidism in human volunteers to delineate TH action on the brain. A battery of neuropsychological testing paradigms was employed and complemented by structural and functional multimodal neuroimaging. Experimentally induced mild thyrotoxicosis for 6 weeks was associated with changes in brain structure (determined with voxel-based morphometry), resting state functional connectivity, and task-related functional activation in a working memory paradigm. Partial withdrawal of TH replacement in patients without thyroid (subclinical hypothyroidism) likewise lead to changes on multiple functional and structural brain measures. Importantly, the series of studies reviewed here identified the cerebellum as one crucial site of action.

A Thyroid Hormone-Independent Molecular Fingerprint of 3,5-Diiodothyronine Suggests a Strong Relationship with Coffee Metabolism in Humans

Background: In numerous studies based predominantly on rodent models, administration of 3,5-diiodo-L-thyronine (3,5-T2), a metabolite of the thyroid hormones (TH) thyroxine (T4) and triiodo-L-thyronine (T3), was reported to cause beneficial health effects, including reversal of steatohepatosis and prevention of insulin resistance, in most instances without adverse thyrotoxic side effects. However, the empirical evidence concerning the physiological relevance of endogenously produced 3,5-T2 in humans is comparatively poor. Therefore, to improve the understanding of 3,5-T2-related metabolic processes, we performed a comprehensive metabolomic study relating serum 3,5-T2 concentrations to plasma and urine metabolite levels within a large general population sample. Methods: Serum 3,5-T2 concentrations were determined for 856 participants of the population-based Study of Health in Pomerania-TREND (SHIP-TREND). Plasma and urine metabolome data were generated using mass spectrometry and nuclear magnetic resonance spectroscopy, allowing quantification of 613 and 578 metabolites in plasma and urine, respectively. To detect thyroid function-independent significant 3,5-T2-metabolite associations, linear regression analyses controlling for major confounders, including thyrotropin and free T4, were performed. The same analyses were carried out using a sample of 16 male healthy volunteers treated for 8 weeks with 250 μg/day levothyroxine to induce thyrotoxicosis. Results: The specific molecular fingerprint of 3,5-T2 comprised 15 and 73 significantly associated metabolites in plasma and urine, respectively. Serum 3,5-T2 concentrations were neither associated with classical thyroid function parameters nor altered during experimental thyrotoxicosis. Strikingly, many metabolites related to coffee metabolism, including caffeine and paraxanthine, formed the clearest positively associated molecular signature. Importantly, these associations were replicated in the experimental human thyrotoxicosis model. Conclusion: The molecular fingerprint of 3,5-T2 demonstrates a clear and strong positive association of the serum levels of this TH metabolite with plasma levels of compounds indicating coffee consumption, therefore pointing to the liver as an organ, the metabolism of which is strongly affected by coffee. Furthermore, 3,5-T2 serum concentrations were found not to be directly TH dependent. Considering the beneficial health effects of 3,5-T2 administration observed in animal models and those of coffee consumption demonstrated in large epidemiological studies, one might speculate that coffee-stimulated hepatic 3,5-T2 production or accumulation represents an important molecular link in this connection.

Unraveling the Molecular Basis for Successful Thyroid Hormone Replacement Therapy: The Need for New Thyroid Tissue- and Pathway-Specific Biomarkers

Thyroid function is conventionally assessed by measurement of thyroid-stimulating hormone (TSH) and free circulating thyroid hormones, which is in most cases sufficient for correct diagnosis and monitoring of treatment efficiency. However, several conditions exist, in which these parameters may be insufficient or even misleading. For instance, both, a TSH-secreting pituitary adenoma and a mutation of thyroid hormone receptor β present with high levels of TSH and circulating hormones, but the optimal treatment is substantially different. Likewise, changes in thyroid hormone receptor α signaling are not captured by routine assessment of thyroid status, as serum parameters are usually inconspicuous. Therefore, new biomarkers are urgently needed to improve the diagnostic management and monitor treatment efficiency for e. g., replacement therapy in hypothyroidism or thyroid hormone resistance. By comparing animal models to human data, the present minireview summarizes the status of this search for new tissue- and pathway-specific biomarkers of thyroid hormone action.

Thyroid Related Quality of Life in Elderly with Subclinical Hypothyroidism and Improvement on Levothyroxine is Distinct from that in Young Patients (TSAGE)

The aim of this study was to investigate in a longitudinal approach whether levothyroxine (LT4) substitution has a different impact on quality of life (QoL) and thyroid related QoL in younger (<40 years) and older subjects (>60 years) with elevated thyroid-stimulating hormone (TSH) concentrations. The study included male and female patients with newly diagnosed, untreated subclinical hypothyroidism defined by TSH>8 mU/l. Patients were recruited throughout Germany from 2013-2016 and evaluated by clinical assessment, blood sampling and questionnaires for health related QoL and thyroid-disease thyroid-related QoL (ThyPRO) at time of diagnosis and six months after initiation of LT4 treatment. We found significantly lower QoL in both young and old patients with subclinical hypothyroidism compared to age-matched healthy individuals. Higher scores on follow-up were found in all patients irrespective of age, indicating better QoL on LT4 therapy. Analysis of the ThyPRO questionnaire showed that old patients experienced less Emotional Susceptibility, Tiredness, and Impaired Day Life on LT4, while young patients reported less Cognitive Complaints, Emotional Susceptibility, and Impaired Day Life compared to baseline assessment. Hypothyroidism with TSH concentrations>8 mU/l is associated with impairment in general and ThyPRO QoL in young and old age. Older patients benefited from LT4 therapy and remarkably show similar degree of improvement as younger patients, albeit with some thematic variation in ThyPRO QoL. Our data confirm current recommendations on initiation of LT4 substitution and suggest that this should not be withheld in elderly with TSH concentration above 8-10 mU/l.

Long-Term Endocrine and Metabolic Consequences of Cancer Treatment: A Systematic Review

The number of patients surviving ≥5 years after initial cancer diagnosis has significantly increased during the last decades due to considerable improvements in the treatment of many cancer entities. A negative consequence of this is that the emergence of long-term sequelae and endocrine disorders account for a high proportion of these. These late effects can occur decades after cancer treatment and affect up to 50% of childhood cancer survivors. Multiple predisposing factors for endocrine late effects have been identified, including radiation, sex, and age at the time of diagnosis. A systematic literature search has been conducted using the PubMed database to offer a detailed overview of the spectrum of late endocrine disorders following oncological treatment. Most data are based on late effects of treatment in former childhood cancer patients for whom specific guidelines and recommendations already exist, whereas current knowledge concerning late effects in adult-onset cancer survivors is much less clear. Endocrine sequelae of cancer therapy include functional alterations in hypothalamic-pituitary, thyroid, parathyroid, adrenal, and gonadal regulation as well as bone and metabolic complications. Surgery, radiotherapy, chemotherapy, and immunotherapy all contribute to these sequelae. Following irradiation, endocrine organs such as the thyroid are also at risk for subsequent malignancies. Although diagnosis and management of functional and neoplastic long-term consequences of cancer therapy are comparable to other causes of endocrine disorders, cancer survivors need individually structured follow-up care in specialized surveillance centers to improve care for this rapidly growing group of patients.

Impact of Hunger, Satiety, and Oral Glucose on the Association Between Insulin and Resting-State Human Brain Activity

To study the interplay of metabolic state (hungry vs. satiated) and glucose administration (including hormonal modulation) on brain function, resting-state functional magnetic resonance imaging (rs-fMRI) and blood samples were obtained in 24 healthy normal-weight men in a repeated measurement design. Participants were measured twice: once after a 36 h fast (except water) and once under satiation (three meals/day for 36 h). During each session, rs-fMRI and hormone concentrations were recorded before and after a 75 g oral dose of glucose. We calculated the amplitude map from blood-oxygen-level-dependent (BOLD) signals by using the fractional amplitude of low-frequency fluctuation (fALFF) approach for each volunteer per condition. Using multiple linear regression analysis (MLRA) the interdependence of brain activity, plasma insulin and blood glucose was investigated. We observed a modulatory impact of fasting state on intrinsic brain activity in the posterior cingulate cortex (PCC). Strikingly, differences in plasma insulin levels between hunger and satiety states after glucose administration at the time of the scan were negatively related to brain activity in the posterior insula and superior frontal gyrus (SFG), while plasma glucose levels were positively associated with activity changes in the fusiform gyrus. Furthermore, we could show that changes in plasma insulin enhanced the connectivity between the posterior insula and SFG. Our results indicate that hormonal signals like insulin alleviate an acute hemostatic energy deficit by modifying the homeostatic and frontal circuitry of the human brain.

Experimentally induced subclinical hypothyroidism causes decreased functional connectivity of the cuneus: A resting state fMRI study

OBJECTIVE

The aim of this study was to experimentally evaluate the effects of subclinical mild hypothyroidism on brain network connectivity as determined by resting state fMRI (rsfMRI) which serves as a proxy for global changes in brain function.

METHODS

Fifteen otherwise healthy patients with complete hypothyroidism under stable, long term levothyroxine substitution volunteered for the study. They reduced their pretest levothyroxine dosage by 30% for 52-56 days. Basally and after partial levothyroxine withdrawal, rsfMRI along with a neuropsychological analysis was performed. RsfMRI was subjected to graph-theory-based analysis to investigate whole-brain intrinsic functional connectivity.

RESULTS

The desired subclinical hypothyroidism was achieved in all subjects. This was associated with a significant decrease in resting-state functional connectivity specifically in the cuneus (0.05 FWE corrected at cluster level) which was mainly caused by a weaker functional connectivity to the cerebellum and regions of the default mode network, i.e. the medial prefrontal cortex, the precuneus and the bilateral angular gyri. The decrease in cuneus connectivity was correlated to the increase in TSH serum levels. A working memory task showed a slightly longer reaction time and less accuracy after partial levothyroxine withdrawal.

CONCLUSION

Even short-term partial levothyroxine partial withdrawal leads to deficits in working memory tasks and to a weaker integration of the cuneus within the default mode network.

Partial withdrawal of levothyroxine treated disease leads to brain activations and effects on performance in a working memory task: A pilot study

Hypothyroidism is associated with memory impairments. The present study aimed to evaluate the effects of partial withdrawal of levothyroxine on working memory tasks and brain function. Fifteen subjects under long-term levothyroxine substitution as a result of complete hypothyroidism participated in the present study. Functional magnetic resonance imaging (MRI) was performed using a working memory task (n-back task) and neuropsychological tests were performed before and 52-54 days after the induction of subclinical hypothyroidism by reducing the pretest levothyroxine dosage by 30%. Reaction time of subjects under partial levothyroxine withdrawal was significantly longer and less accurate with respect to solving the working memory tasks. Functional MRI revealed significant activation changes after medication withdrawal in the cerebellum, insula, parietal, frontal, temporal and occipital lobes, lingual gyrus, and the cuneus. Partial withdrawal of levothyroxine may lead to deficits in a working memory task and to an activation of brain areas associated with working memory ability.

Melatonin secretion following brain midline irradiation is diminished, but not correlated with subjective sleep disturbances

OBJECTIVE

Cranial irradiation for brain tumours or leukaemias has been related to cognitive, endocrine and psychosocial late effects as well as sleep disturbances and increased daytime sleepiness. Studies suggest that cranial irradiation might impact on pineal melatonin secretion. Melatonin is an important regulator in human circadian rhythms and the sleep-wake cycle. The objective of this study was to investigate melatonin secretion, subjective sleep parameters and their interplay in a cohort of cranially irradiated head and brain tumour and leukaemia survivors at least 3 years after radiotherapy.

DESIGN

Cross-sectional study.

PATIENTS

Thirty-eight adults.

MEASUREMENTS

Melatonin secretion was evaluated by measuring its metabolite 6-sulphatoxymelatonin in collected overnight urine. Subjective sleep quality and daytime sleepiness were assessed using the Pittsburgh Sleep Quality Index and the Epworth Sleepiness Scale. The Beck Depression Inventory II was used to screen for depressive symptoms because of their impact on sleep.

RESULTS

Patients irradiated in the brain midline had significantly lower melatonin secretion (P = 0.008). Subjects exhibited a high prevalence of sleeping difficulties, daytime sleepiness and depression, with females and overweight subjects particularly affected. Melatonin values and subjective sleep parameters did not correlate with each other or with treatment and most patient variables.

CONCLUSIONS

Our data suggest that radiation exposure to the pineal gland negatively affects melatonin secretion. This lack of pineal melatonin does not influence subjective sleep quality. As melatonin has important antioxidant and cancer-protective effects, further research is necessary to elucidate whether these patients have an increased risk of developing secondary neoplasms and other radiation late effects.

2018 European Thyroid Association (ETA) Guidelines on the Diagnosis and Management of Central Hypothyroidism

OBJECTIVES

Central hypothyroidism (CeH) is a rare form of hypothyroidism characterized by insufficient thyroid stimulation due to disturbed pituitary and/or hypothalamic functioning. Due to its origin and the whole clinical context, CeH represents a challenging condition in clinical practice as it is characterized by suboptimal accuracy of clinical and biochemical parameters for diagnosis and management. Since no expert consensus or guidance for this condition is currently available, a task force of experts received the commitment from the European Thyroid Association (ETA) to prepare this document based on the principles of clinical evidence.

STUDY DESIGN

The task force started to work in February 2017 and after a careful selection of appropriate references (cohort studies, case reports, expert opinions), a preliminary presentation and live discussion during the 2017 ETA meeting, and several revision rounds, has prepared a list of recommendations to support the diagnosis and management of patients with CeH.

RESULTS

Due to the particular challenges of this rare condition in the different ages, the target users of this guidance are pediatric and adult endocrinologists. Experts agreed on the need to recognize and treat overt CeH at all ages, whereas treatment of milder forms may be dispensable in the elderly (> 75 years).

CONCLUSIONS

Despite the lack of randomized controlled clinical trials, the experts provide 34 recommendations supported by variable levels of strength that should improve the quality of life of the affected patients and reduce the metabolic and hormonal consequences of inadequate management.

A Copeptin-Based Approach in the Diagnosis of Diabetes Insipidus

BACKGROUND

The indirect water-deprivation test is the current reference standard for the diagnosis of diabetes insipidus. However, it is technically cumbersome to administer, and the results are often inaccurate. The current study compared the indirect water-deprivation test with direct detection of plasma copeptin, a precursor-derived surrogate of arginine vasopressin.

METHODS

From 2013 to 2017, we recruited 156 patients with hypotonic polyuria at 11 medical centers to undergo both water-deprivation and hypertonic saline infusion tests. In the latter test, plasma copeptin was measured when the plasma sodium level had increased to at least 150 mmol per liter after infusion of hypertonic saline. The primary outcome was the overall diagnostic accuracy of each test as compared with the final reference diagnosis, which was determined on the basis of medical history, test results, and treatment response, with copeptin levels masked.

RESULTS

A total of 144 patients underwent both tests. The final diagnosis was primary polydipsia in 82 patients (57%), central diabetes insipidus in 59 (41%), and nephrogenic diabetes insipidus in 3 (2%). Overall, among the 141 patients included in the analysis, the indirect water-deprivation test determined the correct diagnosis in 108 patients (diagnostic accuracy, 76.6%; 95% confidence interval [CI], 68.9 to 83.2), and the hypertonic saline infusion test (with a copeptin cutoff level of >4.9 pmol per liter) determined the correct diagnosis in 136 patients (96.5%; 95% CI, 92.1 to 98.6; P<0.001). The indirect water-deprivation test correctly distinguished primary polydipsia from partial central diabetes insipidus in 77 of 105 patients (73.3%; 95% CI, 63.9 to 81.2), and the hypertonic saline infusion test distinguished between the two conditions in 99 of 104 patients (95.2%; 95% CI, 89.4 to 98.1; adjusted P<0.001). One serious adverse event (desmopressin-induced hyponatremia that resulted in hospitalization) occurred during the water-deprivation test.

CONCLUSIONS

The direct measurement of hypertonic saline-stimulated plasma copeptin had greater diagnostic accuracy than the water-deprivation test in patients with hypotonic polyuria. (Funded by the Swiss National Foundation and others; ClinicalTrials.gov number, NCT01940614 .).

Comprehensive assessment of sex hormones in Takotsubo syndrome

BACKGROUND

The detailed pathomechanism of Takotsubo syndrome (TS) is still elusive. Due to the predominance of postmenopausal females, a potential role of sex hormones has been suggested. However, the limited available data are contradictory. The aim of this study was to comprehensively assess the role of sex hormone levels in a large cohort of TS patients.

METHODS

Serum samples of 57 female TS patients and 57 female patients with myocardial infarction (MI), matched for age (±2years) and repolarization disturbances were analyzed for estradiol (E2), estrone (E1), testosterone and androstenedione using liquid chromatography-tandem mass spectrometry.

RESULTS

There was no difference concerning the concentrations of E1 [pmol/l (IQR): 89.1 (62.5, 132.0) vs. 98.8 (63.3, 156.0), p=0,441], testosterone [nmol/l (IQR): 0.67 (0.46, 1.00) vs. 0.80 (0.49, 1.08), p=0.382] and androstenedione [nmol/l (IQR): 2.03 (1.57, 3.11) vs. 2.98 (1.48, 5.27), p=0.244] between female TS and MI patients. Regarding E2, the majority of patients demonstrated concentrations below the detection limit of 30pmol/l (TS: n=41/54, 75.9%; MI: n=32/53, 60.4%; p=0.078). The remaining individuals with detectable E2 concentrations did not show a significant difference between TS and MI patients [pmol/l (IQR): 40.5 (33.0, 53.3) vs. 54.1 (37.9, 60.9); p=0.20].

CONCLUSIONS

Altered sex hormone levels, especially an estradiol deficiency, could not be identified as a risk factor for TS.

Metabolic Syndrome in Thyroid Disease

Cardiometabolic risk factors like abdominal obesity, hyperglycemia, low high-density lipoprotein (HDL) cholesterol, elevated triglycerides, and hypertension are defined as metabolic syndrome (MetS), which represents one of the most frequent endocrine disorders particularly in a society with increasing weight problems. As more and more evidence is accumulated that thyroid hormones affect components of the MetS, the present review aims to summarize the rapidly expanding knowledge on the pathophysiological interaction between thyroid hormone status and MetS. The review is based on a PubMed search for combinations of thyroid hormone action and MetS, blood pressure, hypertension, hyperlipidemia, cholesterol, HDL cholesterol, glucose, diabetes mellitus, body weight, or visceral fat. A special focus was given for manuscripts published after 2000 but we included seminal papers published before year 2000 as well.

Effects of thyroid hormones on thermogenesis and energy partitioning

Thyroid hormones (TH) are of central importance for thermogenesis, energy homeostasis and metabolism. Here, we will discuss these aspects by focussing on the physiological aspects of TH-dependent regulation in response to cold exposure and fasting, which will be compared to alterations in primary hyperthyroidism and hypothyroidism. In particular, we will summarise current knowledge on regional thyroid hormone status in the central nervous system (CNS) and in peripheral cells. In contrast to hyperthyroidism and hypothyroidism, where parallel changes are observed, local alterations in the CNS differ to peripheral compartments when induced by cold exposure or fasting. Cold exposure is associated with low hypothalamic TH concentrations but increased TH levels in the periphery. Fasting results in a reversed TH pattern. Primary hypothyroidism and hyperthyroidism disrupt these fine-tuned adaptive mechanisms and both, the hypothalamus and the periphery, will have the same TH status. These important mechanisms need to be considered when discussing thyroid hormone replacement and other therapeutical interventions to modulate TH status.

Sleep quality and health-related quality of life among long-term survivors of (non-) Hodgkin lymphoma in Germany

This study investigated sleep quality and health-related quality of life (HRQOL) among long-term survivors of Hodgkin (HL) and non-Hodgkin lymphoma (NHL). The aim was to explore the impact of personal and health-related factors on sleep quality as well as associations between sleep quality and HRQOL. For the postal survey, participants with a minimum age of 18 years initially treated between 1998 and 2008 were recruited via the population-based cancer registry in Schleswig-Holstein, Northern Germany. Questionnaires included amongst others the Pittsburg Sleep Quality Index (PSQI) and the 36-Item Short Form Health Survey (SF-36v1). Descriptive and comparative statistics were performed. Additionally, a regression analysis was conducted to identify predictors of sleep quality. In total, we recruited 515 participants (398 NHL, 117 HL) with a mean age of 63.1 years. Approximately half of the survivors were classified as good sleepers. HRQOL scores differed between good and poor sleepers with lower scores in poor sleepers. In a prediction model, self-reported depression, exhaustion, higher age, inability to work, endocrinological disorders and female gender classified as predictors of sleep quality. This study highlights the impact of sleep quality on HRQOL in long-term survivors of NHL and HL. Thus, sleep quality should be routinely assessed during follow-up of cancer survivors with special attention to patients with potential risk factors.

Differential regulation of monocarboxylate transporter 8 expression in thyroid cancer and hyperthyroidism

OBJECTIVE

Thyroid hormone (TH) transporters are expressed in thyrocytes and most play a role in TH release. We asked whether expression of the monocarboxylate transporter 8 (MCT8) and the L-type amino acid transporters LAT2 and LAT4 is changed with thyrocyte dedifferentiation and in hyperfunctioning thyroid tissues.

DESIGN AND METHODS

Protein expression and localization of transporters was determined by immunohistochemistry in human thyroid specimen including normal thyroid tissue (NT, n = 19), follicular adenoma (FA, n = 44), follicular thyroid carcinoma (FTC, n = 45), papillary thyroid carcinoma (PTC, n = 40), anaplastic thyroid carcinoma (ATC, n = 40) and Graves' disease (GD, n = 50) by calculating the 'hybrid' (H) score. Regulation of transporter expression was investigated in the rat follicular thyroid cell line PCCL3 under basal and thyroid stimulating hormone (TSH) conditions.

RESULTS

MCT8 and LAT4 were localized at the plasma membrane, while LAT2 transporter showed cytoplasmic localization. MCT8 expression was downregulated in benign and malignant thyroid tumours as compared to NT. In contrast, significant upregulation of MCT8, LAT2 and LAT4 was found in GD. Furthermore, a stronger expression of MCT8 was demonstrated in PCCL3 cells after TSH stimulation.

CONCLUSIONS

Downregulation of MCT8 in thyroid cancers qualifies MCT8 as a marker of thyroid differentiation. The more variable expression of LATs in distinct thyroid malignancies may be linked with other transporter properties relevant to altered metabolism in cancer cells, i.e. amino acid transport. Consistent upregulation of MCT8 in GD is in line with increased TH release in hyperthyroidism, an assumption supported by our in vitro results showing TSH-dependent upregulation of MCT8.

Copeptin as a marker of an altered CRH axis in pituitary disease

BACKGROUND

Copeptin (pre-proAVP) secreted in equimolar amounts with vasopressin closely reflects vasopressin release. Copeptin has been shown to subtly mirror stress potentially mediated via corticotrophin-releasing hormone. To further test a potential direct interaction of corticotrophin-releasing hormone with copeptin release, which could augment vasopressin effects on pituitary function, we investigated copeptin response to corticotrophin-releasing hormone.

PATIENTS AND METHODS

Cortisol, adrenocorticotropin and copeptin were measured in 18 healthy controls and 29 subjects with a history of pituitary disease during standard corticotrophin-releasing hormone test.

RESULTS

Patients with previous pituitary disease were subdivided in a group passing the test (P1, n = 20) and failing (P2, n = 9). The overall copeptin response was higher in controls than in subjects with pituitary disease (area under the curve, p = 0.04 for P1 + P2) with a maximum increase in controls from 3.84 ± 2.86 to 12.65 ± 24.87 pmol/L at 30 min, p < 0.05. In contrast, both groups of pituitary patients lacked a significant copeptin response to corticotrophin-releasing hormone, and even in P1, where adrenocorticotropin concentrations increased fourfold (mean, 21.48 vs. 91.53 pg/mL, p < 0.01), copeptin did not respond (e.g., 4.35 ± 5.81 vs. 5.36 ± 6.79 pmol/L, at 30 min, p = ns).

CONCLUSIONS

Corticotrophin-releasing hormone is able to stimulate copeptin release in healthy controls suggesting a direct interaction of corticotrophin-releasing hormone and vasopressin/vasopressin. Interestingly, this relation is altered already in the group of pituitary patients who pass the standard corticotrophin-releasing hormone test indicating (1) the corticotrophin-releasing hormone-adrenocorticotropin-cortisol response is largely independent from the vasopressin system, but (2) the corticotrophin-releasing hormone-vasopressin interaction reflected by copeptin may be much more sensitive to reveal subtle alterations in the regulation of pituitary function.

Presence of headache and headache types in patients with tumors of the sellar region-can surgery solve the problem? Results of a prospective single center study

PURPOSE

Headache is a common presenting feature of patients with pituitary adenomas and other tumors of the sellar region. However, at present, it still is unclear whether the headache is actually caused by the tumor. To explore whether there is a relation, we examined in detail the headache types, their relationship to the underlying pathology, and if the headache responded to neurosurgery in a prospective study design.

METHODS

One hundred twelve patients with tumors of the sellar region scheduled for neurosurgery in a single center were analyzed for presence and quality of headache before surgery and at least 3 months after surgery. Patients received headache and depression self-rating inventories, presented on a handheld computer (PainDetect^®). Clinical variables thought to impact on headache were analyzed in conjunction with the inventories.

RESULTS

Fifty-nine (53%) patients reported headache in the 3 months prior to neurosurgery, 49 (44%) had headache at the time of filling in the questionnaires. The four patients with pituitary apoplexy described thunderclap headache. In the other patients diverse headache types were encountered, most frequently migraine. Untreated gonadotroph deficiency was significantly associated with absence of headache, while none of the other clinical and morphological variables related to headache. Presence of headache and disability due to headache were not significantly reduced after surgery.

CONCLUSION

Apart from pituitary apoplexy we detected no specific headache type in our patient group and no significant improvement of headache after neurosurgery. Headache alone constitutes neither a valid diagnostic marker for the presence of tumors of the sellar region nor a sufficient indication for tumor removal.

Plasma proteome and metabolome characterization of an experimental human thyrotoxicosis model

BACKGROUND

Determinations of thyrotropin (TSH) and free thyroxine (FT4) represent the gold standard in evaluation of thyroid function. To screen for novel peripheral biomarkers of thyroid function and to characterize FT4-associated physiological signatures in human plasma we used an untargeted OMICS approach in a thyrotoxicosis model.

METHODS

A sample of 16 healthy young men were treated with levothyroxine for 8 weeks and plasma was sampled before the intake was started as well as at two points during treatment and after its completion, respectively. Mass spectrometry-derived metabolite and protein levels were related to FT4 serum concentrations using mixed-effect linear regression models in a robust setting. To compile a molecular signature discriminating between thyrotoxicosis and euthyroidism, a random forest was trained and validated in a two-stage cross-validation procedure.

RESULTS

Despite the absence of obvious clinical symptoms, mass spectrometry analyses detected 65 metabolites and 63 proteins exhibiting significant associations with serum FT4. A subset of 15 molecules allowed a robust and good prediction of thyroid hormone function (AUC = 0.86) without prior information on TSH or FT4. Main FT4-associated signatures indicated increased resting energy expenditure, augmented defense against systemic oxidative stress, decreased lipoprotein particle levels, and increased levels of complement system proteins and coagulation factors. Further association findings question the reliability of kidney function assessment under hyperthyroid conditions and suggest a link between hyperthyroidism and cardiovascular diseases via increased dimethylarginine levels.

CONCLUSION

Our results emphasize the power of untargeted OMICs approaches to detect novel pathways of thyroid hormone action. Furthermore, beyond TSH and FT4, we demonstrated the potential of such analyses to identify new molecular signatures for diagnosis and treatment of thyroid disorders. This study was registered at the German Clinical Trials Register (DRKS) [DRKS00011275] on the 16th of November 2016.

Mild Thyrotoxicosis Leads to Brain Perfusion Changes: An Arterial Spin Labelling Study

Hypo- and hyperthyroidism have effects on brain structure and function, as well as cognitive processes, including memory. However, little is known about the influence of thyroid hormones on brain perfusion and the relationship of such perfusion changes with cognition. The present study aimed to demonstrate the effect of short-term experimental hyperthyroidism on brain perfusion in healthy volunteers and to assess whether perfusion changes, if present, are related to cognitive performance. It is known that an interaction exists between brain perfusion and cerebral oxygen consumption rate and it is considered that neural activation increases cerebral regional perfusion rate in brain areas associated with memory. Measuring cerebral blood flow may therefore represent a proxy for neural activity. Therefore, arterial spin labelling (ASL) measurements were conducted and later analysed to evaluate brain perfusion in 29 healthy men before and after ingesting thyroid hormones for 8 weeks. Psychological tests concerning memory were performed at the same time-points and the results were correlated with the imaging results. In the hyperthyroid condition, perfusion was increased in the posterior cerebellum in regions connected with cerebral networks associated with cognitive control and the visual cortex compared to the euthyroid condition. In addition, these perfusion changes were positively correlated with changes of performance in the German version of the Auditory Verbal Learning Task [AVLT, Verbaler Lern-und-Merkfähigkeits-Test (VLMT)]. Cerebellar perfusion and function therefore appears to be modulated by thyroid hormones, likely because the cerebellum hosts a high number of thyroid hormone receptors.

Endogenous testosterone is associated with lower amygdala reactivity to angry faces and reduced aggressive behavior in healthy young women

Testosterone and cortisol have been proposed to influence aggressive behavior by altering the neural processing of facial threat signals. However, this has not been investigated in direct social interactions. Here, we explored the joint impact of testosterone, cortisol, and brain reactivity to anger expressions on women’s reactive aggression in the Social Threat Aggression Paradigm (STAP). The STAP is a competitive reaction time task in which the purported opponent displays either an angry or a neutral facial expression at the beginning of each trial and delivers increasingly loud sound blasts to the participants, successfully provoking them. Strikingly, salivary testosterone at scan-time was negatively related to both aggression and basolateral amygdala (BLA) reactivity to angry faces, whereas cortisol had no effect. When the opponent looked angry, BLA-orbitofrontal coupling was reduced, and BLA reactivity was positively related to aggression. The latter relationship was fully mediated by bilateral superior temporal gyrus (STG) activation. Our results thus support previous neurobiological models of aggression, and extend them by demonstrating that fast amygdala responses to threat modulate STG activity in order to favor aggressive retaliation. Furthermore, our study agrees with recent evidence underscoring a fear-reducing and strategically prosocial effect of testosterone on human social behavior.

[Bacterial vaginosis and spontaneous preterm birth]

OBJECTIVE

To determine if bacterial vaginosis is a marker for risk of spontaneous preterm delivery and if its detection and treatment can reduce this risk.

METHODS

Consultation of the database Pubmed/Medline, Science Direct, and international guidelines of medical societies.

RESULTS

Bacterial vaginosis (BV) is a dysbiosis resulting in an imbalance in the vaginal flora through the multiplication of anaerobic bacteria and jointly of a disappearance of well-known protective Lactobacilli. His diagnosis is based on clinical Amsel criteria and/or a Gram stain with establishment of the Nugent score. The prevalence of the BV extraordinarily varies according to ethnic and/or geographical origin (4-58 %), in France, it is close to 7 % in the first trimester of pregnancy (EL2). The link between BV and spontaneous premature delivery is low with an odds ratio between 1.5 and 2 in the most recent studies (EL3). Metronidazole or clindamycin is effective to treat BV (EL3). It is recommended to prescribe one of these antibiotics in the case of symptomatic BV (Professional Consensus). The testing associated with the treatment of BV in the global population showed no benefit in the prevention of the risk of spontaneous preterm delivery (EL2). Concerning low-risk asymptomatic population (defined by the absence of antecedent of premature delivery), it has been failed profit to track and treat the BV in the prevention of the risk of spontaneous preterm delivery (EL1). Concerning the high-risk population (defined by a history of preterm delivery), it has been failed profit to track and treat the VB in the prevention of the risk of spontaneous preterm delivery (EL3). However, in the sub population of patients with a history of preterm delivery occurred in a context of materno-fetal bacterial infection, there may be a benefit to detect and treat early and systematically genital infection, and in particular the BV (Professional Consensus).

CONCLUSION

The screening and treatment of BV during pregnancy in asymptomatic low-risk population is not recommended in the prevention of the risk of spontaneous preterm delivery (grade A). In the population at high risk with the only notion of antecedent of premature delivery, screening and treatment of the BV is not recommended (grade C).

Phosphatidylinositide 3-kinase (PI3K) and PI3K-related kinase (PIKK) activity contributes to radioresistance in thyroid carcinomas

Anaplastic (ATC) and certain follicular thyroid-carcinomas (FTCs) are radioresistant. The Phosphatidylinositide 3-kinase (PI3K) pathway is commonly hyperactivated in thyroid-carcinomas. PI3K can modify the PI3K-related kinases (PIKKs) in response to radiation: How PIKKs interact with PI3K and contribute to radioresistance in thyroid-carcinomas is unknown. Further uncertainties exist in how these interactions function under the radioresistant hypoxic microenvironment. Under normoxia/anoxia, ATC (8505c) and FTC (FTC-133) cells were irradiated, with PI3K-inhibition (via GDC-0941 and PTEN-reconstitution into PTEN-null FTC-133s) and effects on PIKK-activation, DNA-damage, clonogenic-survival and cell cycle, assessed. FTC-xenografts were treated with 5 × 2 Gy, ± 50 mg/kg GDC-0941 (twice-daily; orally) for 14 days and PIKK-activation and tumour-growth assessed. PIKK-expression was additionally assessed in 12 human papillary thyroid-carcinomas, 13 FTCs and 12 ATCs. GDC-0941 inhibited radiation-induced activation of Ataxia-telangiectasia mutated (ATM), ATM-and Rad3-related (ATR) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Inhibition of ATM and DNA-PKcs was PI3K-dependent, since activation was reduced in PTEN-reconstituted FTC-133s. Inhibition of PIKK-activation was greater under anoxia: Consequently, whilst DNA-damage was increased and prolonged under both normoxia and anoxia, PI3K-inhibition only reduced clonogenic-survival under anoxia. GDC-0941 abrogated radiation-induced cell cycle arrest, an effect most likely linked to the marked inhibition of ATR-activation. Importantly, GDC-0941 inhibited radiation-induced PIKK-activation in FTC-xenografts leading to a significant increase in time taken for tumours to triple in size: 26.5 ± 5 days (radiation-alone) versus 31.5 ± 5 days (dual-treatment). PIKKs were highly expressed across human thyroid-carcinoma classifications, with ATM scoring consistently lower. Interestingly, some loss of ATM and DNA-PKcs was observed. These data provide new insight into the mechanisms of hypoxia-associated radioresistance in thyroid-carcinoma.

Oral L-arginine improves endothelial function in healthy individuals older than 70 years

Ageing is associated with progressive endothelial dysfunction in normal humans. Flow-mediated dilation (FMD) of the brachial artery is impaired in elderly individuals with cardiovascular disease and vascular nitric oxide (NO) bioavailability is reduced. We investigated whether oral L-arginine, the substrate for NO synthesis, can improve impaired FMD in healthy very old people. In a prospective, double-blind, randomized crossover trial, 12 healthy old subjects (age 73.8 6 2.7 years) took L-arginine (8 g p.o. two times daily) or placebo for 14 days each, separated by a wash-out period of 14 days. FMD was determined by high-resolution ultrasound in the brachial artery during reactive hyperaemia. Baseline artery diameter was 3.88 6 0.18 mm. l-Arginine signifi cantly improved FMD (to 5.7 6 1.2%, p, 0.0001), whereas placebo had no effect (-0.25 6 0.7%; n.s.). After L-arginine, plasma levels of L-arginine increased signifi cantly (114.9 6 11.6 versus 57.4 6 5.0 mmol/l), but placebo had no effect. As NO synthesis can be antagonized by its endogenous inhibitor asymmetric dimethyl L-arginine (ADMA), we determined ADMA plasma concentrations, which were elevated at baseline in comparison to healthy middle-aged individuals (3.9 6 0.2 versus 1.0 6 0.1 mmol/l; p, 0.0001). ADMA remained unchanged during treatment, but L-arginine supplementation normalized the L-arginine/ADMA ratio (p, 0.05). We conclude that in healthy very old age endothelial function is impaired and may be improved by oral L-arginine supplementation, probably due to normalization of the L-arginine/ADMA ratio.

Effect of Mild Thyrotoxicosis on Performance and Brain Activations in a Working Memory Task

AIMS

Disturbed levels of thyroid hormones are associated with neuropsychiatric disorders, including memory impairments. The aim of this study was to evaluate effects of mild induced thyrotoxicosis on working memory and its neural correlates.

METHODS

Twenty-nine healthy, male subjects with normal thyroid state participated in the study. Functional MRI was acquired during a working memory task (n-back task) before and after ingesting 250 μg L-thyroxin per day for a period of eight weeks. In addition, neuropsychological tests were performed.

RESULTS

In the hyperthyroid condition the subjects showed slower reaction times, but a higher accuracy in the 0-back version of the memory tasks. Fewer differences between euthyroid and hyperthyroid state were seen for the more difficult conditions of the n-back task. FMRI revealed effects of difficulty in the parahippocampal gyrus, supplementary motor area, prefrontal cortex, anterior cingulate cortex, posterior cerebellum, rolandic operculum and insula (p<0.05, FWE corrected). When comparing euthyroid and hyperthyroid condition in relation to task-induced activation, differences of activation were found in the right prefrontal cortex as well as in the right parahippocampal area. In the psychological assessment, the alerting effect in the Attention Network Task (ANT) and four out of five parameters of the auditory verbal learning test (AVLT) showed an increase from euthyroid to hyperthyroid state.

CONCLUSIONS

It can be concluded that even a short-term intake of thyroid hormones leads to an activation of brain areas associated with working memory and to an improvement of accuracy of working memory tasks.

Thermoregulatory and Cardiovascular Consequences of a Transient Thyrotoxicosis and Recovery in Male Mice

Thyroid hormones play a major role in body homeostasis, regulating energy expenditure and cardiovascular function. Given that obese people or athletes might consider rapid weight loss as beneficial, voluntary intoxication with T4 preparations is a growing cause for thyrotoxicosis. However, the long-lasting effects of transient thyrotoxicosis are poorly understood. Here we examined metabolic, thermoregulatory, and cardiovascular function upon induction and recovery from a 2-week thyrotoxicosis in male C57BL/6J mice. Our results showed that T4 treatment caused tachycardia, decreased hepatic glycogen stores, and higher body temperature as expected; however, we did not observe an increase in brown fat thermogenesis or decreased tail heat loss, suggesting that these tissues do not contribute to the hyperthermia induced by thyroid hormone. Most interestingly, when the T4 treatment was ended, a pronounced bradycardia was observed in the animals, which was likely caused by a rapid decline of T3 even below baseline levels. On the molecular level, this was accompanied by an overexpression of cardiac phospholamban and Serca2a mRNA, supporting the hypothesis that the heart depends more on T3 than T4. Our findings therefore demonstrate that a transient thyrotoxicosis can have pathological effects that even persist beyond the recovery of serum T4 levels, and in particular the observed bradycardia could be of clinical relevance when treating hyperthyroid patients.

Prednisolone increases neural reactivity to negative socio-emotional stimuli in healthy young men

Exogenous glucocorticoids are known to trigger affective changes, but these are highly variable across individuals. A better understanding of how synthetic glucocorticoids impact the processing of negative emotions in the human brain might help to predict such changes. In the present functional magnetic resonance imaging (fMRI) study, we sought to uncover the slow effects of a synthetic glucocorticoid infusion on the neural response to socio-emotional scenes using a within-participant, double-blind, placebo-controlled design. In two separate sessions, 20 young males were given either an intravenous prednisolone dose (250mg) or placebo in a cross-over, randomized order. Four hours later, they were scanned while viewing drawings of persons in a neutral or negative emotional situation. On the next morning participants provided a blood sample for serum cortisol measurement, which served as a manipulation check. Prednisolone strongly suppressed morning cortisol, and heightened brain reactivity to emotional stimuli in left amygdala, left caudate head, right inferior frontal gyrus, bilateral supplementary motor area, and right somatosensory cortex. Amygdala reactivity was related to lower self-reported fatigue and higher irritability in the prednisolone condition. Moreover, prednisolone blunted inferior frontal and amygdala connectivity with other regions of the emotion-processing neural circuitry. Our results suggest specific brain pathways through which exogenous glucocorticoids may labilize affect.

Copeptin under glucagon stimulation

Stimulation of growth hormone (GH) and adrenocorticotropic hormone (ACTH) secretion by glucagon is a standard procedure to assess pituitary dysfunction but the pathomechanism of glucagon action remains unclear. As arginine vasopressin (AVP) may act on the release of both, GH and ACTH, we tested here the role of AVP in GST by measuring a stable precursor fragment, copeptin, which is stoichiometrically secreted with AVP in a 1:1 ratio. ACTH, cortisol, GH, and copeptin were measured at 0, 60, 90, 120, 150, and 180 min during GST in 79 subjects: healthy controls (Group 1, n = 32), subjects with pituitary disease, but with adequate cortisol and GH responses during GST (Group 2, n = 29), and those with overt hypopituitarism (Group 3, n = 18). Copeptin concentrations significantly increased over baseline 150 and 180 min following glucagon stimulation in controls and patients with intact pituitary function but not in hypopituitarism. Copeptin concentrations were stimulated over time and the maximal increment correlated with ACTH, while correlations between copeptin and GH were weaker. Interestingly, copeptin as well as GH secretion was significantly attenuated when comparing subjects within the highest to those in the lowest BMI quartile (p < 0.05). Copeptin is significantly released following glucagon stimulation. As this release is BMI-dependent, the time-dependent relation between copeptin and GH may be obscured, whereas the close relation to ACTH suggests that AVP/copeptin release might be linked to the activation of the adrenal axis.

Potential Clinical Utility of Copeptin (C-terminal provasopressin) measurements in clinical medicine

Copeptin is a 39-amino-acids containing glycosylated peptide derived from the C-terminal part of the arginine vasopressin (AVP) precursor. In the process of proteolysis the AVP precursor is processed to AVP, neurophysin II, and copeptin in equimolar amounts. In contrast to AVP, copeptin remains stable for several days at room temperature in serum or plasma. Hence, copeptin serves as a bona fide biomarker of AVP release. We briefly summarise clinical utility of copeptin in the diagnosis of diabetes insipidus. We also discuss potential applications of copeptin measurements in hyponatraemic states, assessment of an anterior pituitary function, as well as a wide range of several acute and chronic medical conditions, such as myocardial infarction, stroke or diabetes mellitus.

Expression Pattern of CDX2, Estrogen and Progesterone Receptors in Primary Gastroenteropancreatic Neuroendocrine Tumors and Metastases

BACKGROUND

A significant number of patients with gastroenteropancreatic neuroendocrine tumors (GEP NETs) present with metastatic disease and with unknown primary in about 15% of cases.

MATERIALS AND METHODS

We analyzed 163 primaries of GEP NET and 115 metastases for expression of caudal type homebox 2 (CDX2), estrogen receptor (ER), progesterone receptor (PR), somatostatin receptor 2a (SSTR2a) and Ki67.

RESULTS

PR was most often positive in pancreatic NET and only rarely in non-pancreatic NET (p<0.001). ER was more frequently expressed in non-pancreatic NET (p<0.001) and was more often positive in females than males (p=0.019). CDX2 was positive in all primaries of the duodenum, ileum and appendix, but was also detected in 24% of metastases with pancreatic primary. SSTR2a and Ki67 did not differ significantly between primaries and metastases.

CONCLUSION

Our data substantiate the value of PR, ER and CDX2 in GEP NET, and steroid hormone receptors, being differentially expressed in male and female patients. Differences between primaries and metastases were small but potentially relevant.

Constructing a molecular interaction network for thyroid cancer via large-scale text mining of gene and pathway events

Background

Biomedical studies need assistance from automated tools and easily accessible data to address the problem of the rapidly accumulating literature. Text-mining tools and curated databases have been developed to address such needs and they can be applied to improve the understanding of molecular pathogenesis of complex diseases like thyroid cancer.

Results

We have developed a system, PWTEES, which extracts pathway interactions from the literature utilizing an existing event extraction tool (TEES) and pathway named entity recognition (PathNER). We then applied the system on a thyroid cancer corpus and systematically extracted molecular interactions involving either genes or pathways. With the extracted information, we constructed a molecular interaction network taking genes and pathways as nodes. Using curated pathway information and network topological analyses, we highlight key genes and pathways involved in thyroid carcinogenesis.

Conclusions

Mining events involving genes and pathways from the literature and integrating curated pathway knowledge can help improve the understanding of molecular interactions of complex diseases. The system developed for this study can be applied in studies other than thyroid cancer. The source code is freely available online at https://github.com/chengkun-wu/PWTEES.

Endogenous Androgens and Sex Hormone-Binding Globulin in Women and Risk of Metabolic Syndrome and Type 2 Diabetes

CONTEXT AND OBJECTIVES

The association of endogenous androgens and sex hormone-binding globulin (SHBG) with metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) mostly 23562 refers to small and selected study samples with immunoassay-based measurements. Thus, we investigated the association of hormone levels with MetS and T2DM in women from a large population-based sample.

DESIGN, SETTING, AND PARTICIPANTS

A total of 2077 women from the Study of Health in Pomerania were assessed at baseline (N = 3160, 1997-2001) and 5-year follow-up (N = 1711, 2002-2006).

MAIN OUTCOMES AND MEASURES

We investigated associations of total testosterone (T) and androstenedione measured by liquid chromatography-tandem mass spectrometry, SHBG by immunoassay, and free T and free androgen index with MetS and T2DM.

RESULTS

Baseline prevalence of MetS and T2DM was 23.1% (N = 365) and 9.5% (N = 196), with an incidence of 17.7 and 7.0 per 1.000 person-years, respectively. Cross-sectional analyses yielded inverse associations of SHBG with MetS (relative risk [RR], 0.67; 95% confidence interval [CI], 0.60-0.74) and T2DM (RR, 0.61; 95% CI, 0.50-0.74) after multivariable adjustment. In longitudinal analyses, only age-adjusted models showed an inverse association of baseline SHBG with incident MetS (RR, 0.61; 95% CI, 0.51-0.73) and T2DM (RR, 0.58; 95% CI, 0.43-0.78). Multivariable-adjusted models stratified by menopausal status revealed an inverse association between SHBG and incident MetS risk in postmenopausal women (RR, 0.65; 95% CI, 0.51-0.81).

CONCLUSIONS

This longitudinal population-based study revealed independent inverse associations of SHBG with MetS and T2DM, suggesting low SHBG as a potential risk marker for cardiometabolic morbidity, especially among postmenopausal women.

Effect of Experimental Thyrotoxicosis onto Blood Coagulation: A Proteomics Study

BACKGROUND

Hyperthyroidism is known to induce a hypercoagulable state. It stimulates plasma levels of procoagulative factors and reduces fibrinolytic activity. So far most of the data have been derived from patients with endogenous hyperthyroidism with a wide variability in the underlying pathogenesis and severity of the disease.

OBJECTIVES

In this study we experimentally induced thyrotoxicosis in healthy volunteers to explore the effects of thyroxine excess on the plasma proteome. Using a shotgun proteomics approach, the abundance of plasma proteins was monitored before, during and after thyrotoxicosis.

METHODS

Sixteen healthy male subjects were sampled at baseline, 4 and 8 weeks under 250 µg/day thyroxine p.o., as well as 4 and 8 weeks after stopping the application. Plasma proteins were analyzed after depletion of 6 high-abundance proteins (MARS6) by LC-ESI-MS/MS mass spectrometry. Mass spectrometric raw data were processed using a label-free, intensity-based workflow. Subsequently, the linear dependence between protein abundances and fT4 levels were calculated using a Pearson correlation.

RESULTS

All subjects developed biochemical thyrotoxicosis, and this effect was reversed within the first 4 weeks of follow-up. None of the volunteers noticed any subjective symptoms. Levels of 10 proteins involved in the coagulation cascade specifically correlated with fT4, supporting an influence of thyroid hormone levels on blood coagulation even at nonpathological levels.

CONCLUSIONS

The results suggest that experimental thyrotoxicosis exerts selective and specific thyroxine-induced effects on coagulation markers. Our study design allows assessment of thyroid hormone effects on plasma protein levels without secondary effects of other diseases or therapies.

One injection of platelet-rich plasma associated to a submaximal eccentric protocol to treat chronic jumper's knee

AIM

Jumper's knee is a frequent chronic overuse syndrome of the proximal part of the patellar tendon. Platelets contain lots of growth factors which could enhance the healing process of tendons. The aim of this study was to clarify the possible efficacy of one injection of Platelet-rich plasma (PRP) in cases of rebel jumper's knees.

METHODS

Twenty patients with chronic proximal patellar tendinopathy were enrolled. Assessments were made before infiltration of PRP, and 6 weeks and 3 months after the infiltration, using a 10-point visual analogic scale of pain, clinical examinations with a pressure algometer, algofunctional scores (IKDC and VISA-P), functional assessments (isokinetic and optojump evaluations) and imagery (ultrasounds and MRI). The PRP was obtained with an apheresis system (COMTEC®, Fresenius-Kabi, Bad Homburg, Germany). Six millilitres of PRP were injected without local anesthetic. One week after infiltration, patients started a standardized sub-maximal eccentric reeducation.

RESULTS

During daily activities pain significantly decreased with time. At functional evaluation, it decreased as well, but without significant functional improvement. No improvements in the imagery measurements were observed. Younger patients seemed to be more susceptible to have an improvement of pain by the PRP infiltration.

CONCLUSION

This study demonstrates that a local infiltration of PRP associated with a submaximal eccentric protocol can improve symptoms of chronic jumper's knee in patients non-responsive to classical conservative treatments.

Effect of Experimental Thyrotoxicosis on Brain Gray Matter: A Voxel-Based Morphometry Study

BACKGROUND

Hyper-as well hypothyroidism have an effect on behavior and brain function. Moreover, during development thyroid hormones influence brain structure.

OBJECTIVES

This study aimed to demonstrate an effect of experimentally induced hyperthyroidism on brain gray matter in healthy adult humans.

METHODS

High-resolution 3D T1-weighted images were acquired in 29 healthy young subjects prior to as well as after receiving 250 µg of T4 per day for 8 weeks. Voxel-based morphometry analysis was performed using Statistical Parametric Mapping 8 (SPM8).

RESULTS

Laboratory testing confirmed the induction of hyperthyroidism. In the hyperthyroid condition, gray matter volumes were increased in the right posterior cerebellum (lobule VI) and decreased in the bilateral visual cortex and anterior cerebellum (lobules I-IV) compared to the euthyroid condition.

CONCLUSIONS

Our study provides evidence that short periods of hyperthyroidism induce distinct alterations in brain structures of cerebellar regions that have been associated with sensorimotor functions as well as working memory in the literature.