The need for the GREAT+ score to predict relapse in Graves' disease: a questionnaire among patients and internal medicine specialists.

PURPOSE: Graves' disease (GD) is an auto-immune cause of hyperthyroidism. First-line treatment often consists of a 12-18 month course of antithyroid drugs (ATD). After discontinuation of ATD, GD relapses in approximately 50% of patients. The 'Graves recurrent event after therapy+ ' (GREAT+) score may predict individual relapse chances after ATD discontinuation more accurately based on clinical and laboratory parameters at diagnosis. We investigated the need for the GREAT+ score through an online questionnaire among GD patients and physicians treating GD. METHODS: An anonymous online questionnaire was distributed to patients and physicians between June 2022 and August 2023. RESULTS: The questionnaire was completed by 532 patients and 44 physicians. Results showed that 94% of patients were interested in knowing their GREAT+ score at the start of treatment. 55% would consider definite treatment (radioiodine/thyroidectomy) as first-line treatment in case of a high relapse chance. 98% of the physicians indicated the GREAT + score would support patient counseling. 84% may change their advice for first-line treatment if a patient has a high relapse chance based on the score. CONCLUSION: Patients and physicians considered the GREAT+ score as a valuable addition to the current available information which could change treatment decisions. Therefore, external validation of the GREAT+ score is justified to implement this score in clinical practice.

Universal screening for thyroid disease SHOULD NOT be recommended before and during pregnancy.

Thyroid dysfunction in pregnancy is strongly associated with adverse maternal and foetal outcomes. The effects of treatment are less clear. There is ongoing discussion on whom to treat, when to treat and whether treatment is beneficial. Although universal screening for thyroid disease during pregnancy increases diagnosis and treatment of thyroid dysfunction, there is currently insufficient evidence demonstrating a positive effect of screening on maternal and foetal outcomes. We therefore, at present, recommend against universal screening for thyroid disease before and during pregnancy.

Nationwide study of patients with head and neck paragangliomas carrying SDHB germline mutations.

BACKGROUND: Germline mutations in the succinate dehydrogenase B (SDHB) gene predispose to hereditary paraganglioma (PGL) syndrome type 4. The aim of this study was to evaluate the clinical characteristics and outcome of treatment strategies for patients with head and neck paraganglioma (HNPGL) carrying SDHB germline mutations. METHODS: This was a retrospective evaluation of patients with HNPGL carrying SDHB germline mutations in the Netherlands. RESULTS: In a Dutch nationwide cohort study of SDHB germline mutation carriers, 54 patients with a total of 62 HNPGLs were identified. Forty-one of 54 patients (76 per cent) visited the outpatient clinic because of associated complaints. Eight patients (15 per cent) had multiple PGLs. One patient (2 per cent) developed a phaeochromocytoma and three (6 per cent) developed a malignant PGL. Twenty-seven patients (50 per cent) had an operation for their HNPGL and 15 (28 per cent) received radiotherapy. Three patients with HNPGL (6 per cent) were diagnosed with additional non-paraganglionic tumours. CONCLUSION: If an SDHB germline mutation is identified in a patient with HNPGL, the clinician should be aware of the variable manifestations of the SDHB-linked tumour syndrome, the risk of catecholamine excess, concurrent phaeochromocytoma, and association with non-paraganglionic tumours.

DNA methylation profiling in MEN1-related pancreatic neuroendocrine tumors reveals a potential epigenetic target for treatment.

OBJECTIVE: Epigenetic changes contribute to pancreatic neuroendocrine tumor (PanNET) development. Hypermethylation of promoter DNA as a cause of tumor suppressor gene silencing is a well-established oncogenic mechanism that is potentially reversible and therefore an interesting therapeutic target. Multiple endocrine neoplasia type 1 (MEN1) is the most frequent cause of inherited PanNETs. The aim of this study was to determine promoter methylation profiles in MEN1-related PanNETs. DESIGN AND METHODS: Methylation-specific multiplex ligation-dependent probe amplification was used to assess promoter methylation of 56 tumor suppressor genes in MEN1-related (n = 61) and sporadic (n = 34) PanNETs. Differences in cumulative methylation index (CMI), individual methylation percentages and frequency of promoter hypermethylation between subgroups were analyzed. RESULTS: We found promoter methylation of a large number of potential tumor suppressor genes. CMI (median CMI: 912 vs 876, P = 0.207) was the same in MEN1-related and sporadic PanNETs. We found higher methylation percentages of CASP8 in MEN1-related PanNETs (median: 59% vs 16.5%, P = 0.002). In MEN1-related non-functioning PanNETs, the CMI was higher in larger PanNETs (>2 cm) (median: 969.5 vs 838.5; P = 0.021) and in PanNETs with liver metastases (median: 1036 vs 869; P = 0.013). Hypermethylation of MGMT2 was more frequent in non-functioning PanNETs compared to insulinomas (median: 44.7% vs 8.3%; P = 0.022). Hypermethylation of the Von Hippel-Lindau gene promoter was observed in one MEN1-related PanNET and was associated with loss of protein expression. CONCLUSION: Promoter hypermethylation is a frequent event in MEN1-related and sporadic PanNETs. Targeting DNA methylation could be of therapeutic value in MEN1 patients with advanced PanNETs.

The penetrance of paraganglioma and pheochromocytoma in SDHB germline mutation carriers.

Germline mutations in succinate dehydrogenase B (SDHB) predispose to hereditary paraganglioma (PGL) syndrome type 4. The risk of developing PGL or pheochromocytoma (PHEO) in SDHB mutation carriers is subject of recent debate. In the present nationwide cohort study of SDHB mutation carriers identified by the clinical genetics centers of the Netherlands, we have calculated the penetrance of SDHB associated tumors using a novel maximum likelihood estimator. This estimator addresses ascertainment bias and missing data on pedigree size and structure. A total of 195 SDHB mutation carriers were included, carrying 27 different SDHB mutations. The 2 most prevalent SDHB mutations were Dutch founder mutations: a deletion in exon 3 (31% of mutation carriers) and the c.423+1G>A mutation (24% of mutation carriers). One hundred and twelve carriers (57%) displayed no physical, radiological or biochemical evidence of PGL or PHEO. Fifty-four patients had a head and neck PGL (28%), 4 patients had a PHEO (2%), 26 patients an extra-adrenal PGL (13%). The overall penetrance of SDHB mutations is estimated to be 21% at age 50 and 42% at age 70 when adequately corrected for ascertainment. These estimates are lower than previously reported penetrance estimates of SDHB-linked cohorts. Similar disease risks are found for different SDHB germline mutations as well as for male and female SDHB mutation carriers.

Expression of p27Kip1 and p18Ink4c in human multiple endocrine neoplasia type 1-related pancreatic neuroendocrine tumors.

PURPOSE: Pancreatic neuroendocrine tumors are a major manifestation of multiple endocrine neoplasia type 1 (MEN1). This tumor syndrome is caused by germline mutations in MEN1, encoding menin. Insight into pathogenesis of these tumors might lead to new biomarkers and therapeutic targets for these patients. Several lines of evidence point towards a role for p27Kip1 and p18Ink4c in MEN1-related tumor development in animal models for MEN1, but their contribution to human MEN1-related pancreatic neuroendocrine tumor development is not known. METHODS: In this study, we characterized protein expression of p27Kip1 and p18Ink4c in human MEN1-related PanNETs by immunohistochemistry. From the nationwide DutchMEN1 Study Group database including > 90% of the Dutch MEN1 population, MEN1-patients, who underwent pancreatic surgery, were selected. A tissue micro-array was constructed with available paraffin tissue blocks, and PanNETs from 61 MEN1 patients were eligible for analysis. RESULTS: Expression of p27Kip1 was high in 57 (93%) PanNETs and 67% of the tumors showed low expression of p18Ink4c (67.3%). No association was found between expression of either p27Kip1 or p18Ink4c and clinic-pathological characteristics. CONCLUSIONS: These findings indicate that loss of p18Ink4c, but not p27Kip1, is a common event in the development of MEN1-related PanNETs. Restoration of p18Ink4c function through CDK4/6 inhibitors could be a therapeutic option for MEN1-related PanNETs.

Rare NOX3 Variants Confer Susceptibility to Agranulocytosis During Thyrostatic Treatment of Graves' Disease.

Agranulocytosis is a rare and serious adverse effect of antithyroid drugs, with unknown etiology. The present study aimed to uncover genetic susceptibility and underlying mechanisms of antithyroid drug-induced agranulocytosis (ATDAC). We studied two independent families with familial Graves' disease, of which several members developed ATDAC. In addition, six sporadic ATDAC patients with Graves' disease were investigated. Whole exome sequencing analysis of affected and unaffected family members was performed to identify genetic susceptibility variants for ATDAC, followed by functional characterization of primary granulocytes from patients and unrelated healthy controls. Whole exome sequencing, cosegregation analysis, and stringent selection criteria of candidate gene variants identified NOX3 as a genetic factor related to ATDAC. Functional studies revealed increased apoptosis of methimazole-treated granulocytes from patients carrying NOX3 variants. In conclusion, genetic variants in NOX3 may confer susceptibility to antithyroid drug-induced apoptosis of granulocytes. These findings contribute to the understanding of the mechanisms underlying ATDAC.

Effects of Chronic Estrogen Administration in the Ventromedial Nucleus of the Hypothalamus (VMH) on Fat and Bone Metabolism in Ovariectomized Rats.

Estrogen deficiency after ovariectomy (OVX) results in increased adiposity and bone loss, which can be prevented by systemic 17-ß estradiol (E2) replacement. Studies in transgenic mice suggested that in addition to direct actions of estrogen in peripheral tissues, also estrogen signaling in the hypothalamus regulates fat distribution and bone metabolism. We hypothesized that the protective effect of systemic E2 on fat and bone metabolism in the OVX model is partly mediated through the ventromedial nucleus of the hypothalamus (VMH). To test this hypothesis, we determined the effect of systemic, central, and targeted VMH administration of E2 on fat and bone metabolism in OVX rats. Subcutaneous administration of E2 for 4 weeks decreased body weight, gonadal and perirenal fat, and bone formation rate in OVX rats. This effect was completely mimicked by intracerebroventricular injections of E2, once every 4 days for 4 weeks. Administration of E2 locally in the VMH by retromicrodialysis (3 h) acutely increased expression of the lipolytic gene hormone-sensitive lipase in gonadal and perirenal fat. Finally, chronic administration of E2 in the VMH for 8 weeks decreased perirenal fat but did not affect body weight, trabecular bone volume, or cortical thickness. In conclusion, we demonstrated that intracerebroventricular E2 replacement reduces body weight gain, ameliorates intraabdominal fat accumulation, and reduces bone formation in the OVX rats. E2 administration selectively in the VMH also reduced intraabdominal fat but did not affect bone metabolism.

A model for chronic, intrahypothalamic thyroid hormone administration in rats.

In addition to the direct effects of thyroid hormone (TH) on peripheral organs, recent work showed metabolic effects of TH on the liver and brown adipose tissue via neural pathways originating in the hypothalamic paraventricular and ventromedial nucleus (PVN and VMH). So far, these experiments focused on short-term administration of TH. The aim of this study is to develop a technique for chronic and nucleus-specific intrahypothalamic administration of the biologically active TH tri-iodothyronine (T3). We used beeswax pellets loaded with an amount of T3 based on in vitro experiments showing stable T3 release (∼5 nmol l(-1)) for 32 days. Upon stereotactic bilateral implantation, T3 concentrations were increased 90-fold in the PVN region and 50-fold in the VMH region after placing T3-containing pellets in the rat PVN or VMH for 28 days respectively. Increased local T3 concentrations were reflected by selectively increased mRNA expression of the T3-responsive genes Dio3 and Hr in the PVN or in the VMH. After placement of T3-containing pellets in the PVN, Tshb mRNA was significantly decreased in the pituitary, without altered Trh mRNA in the PVN region. Plasma T3 and T4 concentrations decreased without altered plasma TSH. We observed no changes in pituitary Tshb mRNA, plasma TSH, or plasma TH in rats after placement of T3-containing pellets in the VMH. We developed a method to selectively and chronically deliver T3 to specific hypothalamic nuclei. This will enable future studies on the chronic effects of intrahypothalamic T3 on energy metabolism via the PVN or VMH.

Clonidine increases bone resorption in humans.

SUMMARY: Inhibition of sympathetic signaling to bone reduces bone resorption in rodents. In contrast, we show that pharmacological reduction of the sympathetic tone increases bone resorption in humans in vivo. This effect does not appear to be mediated via a direct pharmacological effect on the osteoclast. INTRODUCTION: Inhibition of sympathetic signaling to bone reduces bone resorption in rodents. It is uncertain whether a similar role for the sympathetic nervous system exists in humans. The sympathetic tone can be reduced by clonidine, which acts via alpha-2-adrenergic receptors in the brainstem. Our objective was to determine the effect of clonidine on bone turnover in humans. METHODS: The acute effect of a single oral dose of 0.3 mg clonidine on serum bone turnover markers (C-terminal cross-linking telopeptides of collagen type I (CTx), a marker for bone resorption, and procollagen type 1 N propeptide (P1NP), a marker for bone formation) was determined in a randomized crossover design in 12 healthy volunteers, aged 18-70 years. In addition, we assessed the effect of clonidine on the number of tartrate-resistant acid phosphatase-positive multinucleated cells (TRAcP(+) MNCs) and bone resorption. RESULTS: CTx concentrations increased after clonidine treatment compared to the control condition (p = 0.035). P1NP concentrations were not affected by clonidine (p = 0.520). In vitro, clonidine had no effect on the number of TRAcP(+) MNCs (p = 0.513) or on bone resorption (p = 0.996). CONCLUSIONS: We demonstrated that clonidine increases bone resorption in humans in vivo. This effect does not appear to be mediated via a direct effect on the osteoclast.

Effect of levothyroxine on live birth rate in euthyroid women with recurrent miscarriage and TPO antibodies (T4-LIFE study).

BACKGROUND: Thyroid peroxidase antibodies (TPO-Ab) in euthyroid women are associated with recurrent miscarriage (RM) and other pregnancy complications such as preterm birth. It is unclear if treatment with levothyroxine improves pregnancy outcome. AIM: The aim of this study is to determine the effect of levothyroxine administration on live birth rate in euthyroid TPO-Ab positive women with recurrent miscarriage. METHODS/DESIGN: We will perform a multicenter, placebo controlled randomized trial in euthyroid women with recurrent miscarriage and TPO-Ab. Recurrent miscarriage is defined as two or more miscarriages before the 20th week of gestation. The primary outcome is live birth, defined as the birth of a living fetus beyond 24weeks of gestation. Secondary outcomes are ongoing pregnancy at 12weeks, miscarriage, preterm birth, (serious) adverse events, time to pregnancy and survival at 28days of neonatal life. The analysis will be performed according to the intention to treat principle. We need to randomize 240 women (120 per group) to demonstrate an improvement in live birth rate from 55% in the placebo group to 75% in the levothyroxine treatment group. This trial is a registered trial (NTR 3364, March 2012). Here we discuss the rationale and design of the T4-LIFE study, an international multicenter randomized, double blind placebo controlled, clinical trial aimed to assess the effectiveness of levothyroxine in women with recurrent miscarriage and TPO-Ab.

Association of polymorphisms in the beta-2 adrenergic receptor gene with fracture risk and bone mineral density.

UNLABELLED: Signaling through the beta-2 adrenergic receptor (B2AR) on the osteoblast influences bone remodeling in rodents. In the B2AR gene, three polymorphisms influence receptor function. We show that these polymorphisms are not associated with fracture risk or bone mineral density in the UCP, Rotterdam Study, and GEFOS cohorts. INTRODUCTION: Signaling through the beta-2 adrenergic receptor (B2AR) on the osteoblast influences bone remodeling in rodents. In the B2AR gene, three polymorphisms are known to influence receptor function in vitro and in vivo (rs1042713, rs1042714, and rs1800888). We examined the role of these polymorphisms in the B2AR gene on human bone metabolism. METHODS: We performed nested case-control studies to determine the association of these polymorphisms with fracture risk in the Utrecht Cardiovascular Pharmacogenetics (UCP) cohort and in three cohorts of the Rotterdam Study. We also determined the association of these polymorphisms with bone mineral density (BMD) in the GEFOS Consortium. UCP contains drug-dispensing histories from community pharmacies linked to national registrations of hospital discharges in the Netherlands. The Rotterdam Study is a prospective cohort study investigating demographics and risk factors of chronic diseases. GEFOS is a large international collaboration studying the genetics of osteoporosis. Fractures were defined by ICD-9 codes 800-829 in the UCP cohort (158 cases and 2617 unmatched controls) and by regular X-ray examinations, general practitioner, and hospital records in the Rotterdam Study (2209 cases and 8559 unmatched controls). BMD was measured at the femoral neck and lumbar spine using dual-energy X-ray absorptiometry in GEFOS (N = 32,961). RESULTS: Meta-analysis of the two nested case-control studies showed pooled odds ratios of 0.98 (0.91-1.05, p = 0.52), 1.04 (0.97-1.12, p = 0.28), and 1.16 (0.83-1.62, p = 0.38) for the associations between rs1042713, rs1042714, and rs1800888 per minor allele and fractures, respectively. There were no significant associations of the polymorphisms and BMD in GEFOS. CONCLUSION: In conclusion, polymorphisms in the beta-2 adrenergic receptor gene are not associated with fracture risk or BMD.

The water deprivation test and a potential role for the arginine vasopressin precursor copeptin to differentiate diabetes insipidus from primary polydipsia.

The water deprivation test is the gold standard test to differentiate central or nephrogenic diabetes insipidus (DI) from primary polydipsia (PP) in patients with polyuria and polydipsia. Few studies have addressed the diagnostic performance of this test. The aim of this retrospective cohort study was to evaluate the diagnostic performance of the standard water deprivation test, including plasma arginine vasopressin (AVP) measurements, in 40 consecutive patients with polyuria. We compared initial test results with the final clinical diagnosis, i.e., no DI, central DI, or nephrogenic DI. The median length of follow-up was 8 years. In a subset of ten patients, the novel marker copeptin (CP) was measured in plasma. Using the final diagnosis as a gold standard, a threshold for urine osmolality of >800 mOsmol/kg after water deprivation yielded a sensitivity and specificity of 96 and 100%, respectively, for diagnosing PP. Sensitivity increased to 100% if the cut-off value for urine osmolality was set at 680 mOsmol/kg. Plasma AVP levels did not differ between patient groups and did not differentiate among central DI, nephrogenic DI, or PP. In all three patients with central DI, plasma CP was <2.5 pmol/l with plasma osmolality >290 mOsmol/kg, and >2.5 pmol/l in patients without DI. The optimal cut-off value for differentiating PP from DI during a water deprivation test was urine osmolality >680 mOsmol/kg. Differentiating between central and nephrogenic DI should be based on clinical judgment as AVP levels did not discriminate.

Pathophysiological aspects of thyroid hormone disorders/thyroid peroxidase autoantibodies and reproduction.

BACKGROUND: Thyroid hormone disorders and thyroid peroxidase autoantibodies (TPO-Ab) in women are associated with subfertility and early pregnancy loss. Here, we aim to provide a comprehensive overview of the literature on the pathophysiology of these associations. METHODS: A review of the literature in the English language was carried out. Relevant studies were identified by searching Medline, EMBASE and the Cochrane Controlled Trials Register from 1975 until March 2014. RESULTS: From a total of 6108 primary selected articles from the literature search, 105 articles were selected for critical appraisal. Observational data indicate that altered thyroid hormone levels are associated with disturbed folliculogenesis, spermatogenesis, lower fertilization rates and lower embryo quality. Triiodothyronine (T3) in combination with FSH enhances granulosa cell proliferation and inhibits granulosa cell apoptosis by the PI3K/Akt pathway. T3 is considered a biological amplifier of the stimulatory action of gonadotrophins on granulosa cell function. T3 increases the expression of matrix metalloproteinases (MMP), MMP-2, MMP-3, fetal fibronectin and integrin α5ß1T3 in early placental extravillous trophoblasts. Thyroid hormone transporters and receptors are expressed in the ovary, early embryo, endometrium, uterus and placenta. No other data explaining the associations could be retrieved from the literature. The presence of TPO-Ab is negatively associated with spermatogenesis, fertilization and embryo quality, but no data are available on the potential pathophysiological mechanisms. CONCLUSIONS: Thyroid hormone disorders and TPO-Ab are associated with disturbed folliculogenesis, spermatogenesis, fertilization and embryogenesis. The pathophysiology of these associations remains largely unknown, as evidence is limited and includes studies using small sample sizes, and often restricted to animal models. There are no studies on the pathophysiology underlying the association between TPO-Ab and reproduction. The available evidence, although limited, supports a role of thyroid hormone in fertility and early pregnancy. This justifies clinical intervention studies on the effects of thyroid hormone supplementation in women with subclinical hypothyroidism and in women prone to develop hypothyroidism due to the presence of TPO-Ab. In addition, more research is needed to identify the underlying mechanisms. This would be of particular interest in women undergoing IVF to pinpoint the effects of thyroid hormone on different parameters of reproduction.

The effects of beta-2 adrenergic agonist and antagonist on human bone metabolism: a randomized controlled trial.

PURPOSE: Genetic knockout or pharmacological inhibition of the beta-2 adrenergic receptor (B2AR) increased bone mass, whereas stimulation decreased bone mass in rodents. In humans, observational studies support sympathetic nervous system regulation of bone metabolism, but intervention studies are lacking. We aimed to determine the effects of a selective beta-2 adrenergic agonist and non-selective antagonist on human bone metabolism. METHODS: 32 healthy postmenopausal women were included in a randomized controlled trial conducted in the Academic Medical Center Amsterdam. Participants were randomized to receive treatment with 17-ß estradiol 2mg/day; 17-ß estradiol 2mg/day and terbutaline 5mg/day (selective B2AR agonist); propranolol 80mg/day (non-selective B-AR antagonist); or no treatment during 12weeks. Main outcome measure was the change in serum concentrations of procollagen type I N propeptide (P1NP) and C-terminal crosslinking telopeptides of collagen type I (CTx) as markers of bone formation and resorption after 12weeks compared between the treatment groups. Data were analyzed with mixed model analysis. RESULTS: 17-ß estradiol decreased bone turnover compared to control (P1NP p<0.001, CTx p=0.003), but terbutaline combined with 17-ß estradiol failed to increase bone turnover compared to 17-ß estradiol alone (P1NP p=0.135, CTx p=0.406). Propranolol did not affect bone turnover compared to control (P1NP p=0.709, CTx p=0.981). CONCLUSION: Selective beta-2 adrenergic agonists and non-selective beta-antagonists do not affect human bone turnover although we cannot exclude small changes below the detection limit of this study.

Osteocalcin and the pituitary-gonadal axis in older men: a population-based study.

OBJECTIVE: Osteocalcin is a well-known marker of bone formation. Recently, mice lacking osteocalcin or its receptor were reported to be subfertile with low testosterone and high luteinizing hormone concentrations. In parallel, in humans, a loss-of-function mutation of the osteocalcin receptor was associated with hypergonadotropic hypogonadism. This suggests that osteocalcin is necessary for normal pituitary-gonadal axis function. Our objective was to determine the association between physiological variations in osteocalcin and the pituitary-gonadal axis in older men. DESIGN AND PATIENTS: Data were used from the Longitudinal Aging Study Amsterdam (LASA), an ongoing cohort study in a representative sample of the older Dutch population (65-88 years). MEASUREMENTS: Serum levels of total (T), free (FT) and bioavailable (bioT) testosterone, luteinizing hormone (LH) and osteocalcin were determined. Data were analysed using linear regression analyses and adjusted for age, BMI, 25-hydroxyvitamin D, parathyroid hormone and vitamin K antagonist use. RESULTS: A total of 614 men participated in the study. The median age was 75·4 (69·8-81·2) years, and the median osteocalcin level was 1·8 (1·3-2·4) nmol/l. Serum osteocalcin was inversely associated with FT (adjusted B = -0·22 ± 0·09 ng/dl, P = 0·012) and bioT (adjusted B = -0·26 ± 0·08 nmol/l, P < 0·01), but not with total T. Furthermore, osteocalcin was positively associated with LH (adjusted B = 0·09 ± 0·03 U/l, P < 0·01). CONCLUSIONS: Serum osteocalcin was negatively associated with free and bioavailable testosterone and positively with luteinizing hormone levels.

Venous thromboembolism in overt hyperthyroidism - a direct association with clinical implications?

Hyperthyroidism is associated with procoagulant changes in the haemostatic system. At present, it is uncertain whether this leads to an increased risk of venous and/or arterial thrombosis. Only a few small studies have investigated this association but due to methodological limitations it is not possible to draw any definitive conclusions at this stage. Here we report two patients with severe venous thromboembolism (VTE) and concomitant hyperthyroidism without any risk factors for VTE. Hereby, we emphasise a possible association as supported by a number of previous studies. In a planned prospective multicentre cohort study we will examine the association between hyperthyroidism and VTE and determine its clinical relevance.

Bone as a regulator of glucose metabolism.

For a long time the only functions attributed to the skeleton were locomotion and calcium storage. Over the last decade, this view has changed. Genetic studies in mice have shown that bone metabolism is regulated by the autonomic nervous system and interacts with energy metabolism and reproduction. Osteocalcin, one of the main organic ingredients of the bone matrix, was discovered to stimulate insulin production by the pancreas, as well as energy expenditure and insulin sensitivity. Administration of recombinant osteocalcin to mice on a high fat diet decreased weight gain and insulin resistance. These unanticipated results stimulated studies on osteocalcin and glucose metabolism in humans. This review will discuss these clinical studies and their perspective for the future.

Variable loss of functional activities of androgen receptor mutants in patients with androgen insensitivity syndrome.

Androgen receptor (AR) mutations in androgen insensitivity syndrome (AIS) are associated with a variety of clinical phenotypes. The aim of the present study was to compare the molecular properties and potential pathogenic nature of 8 novel and 3 recurrent AR variants with a broad variety of functional assays. Eleven AR variants (p.Cys177Gly, p.Arg609Met, p.Asp691del, p.Leu701Phe, p.Leu723Phe, p.Ser741Tyr, p.Ala766Ser, p.Arg775Leu, p.Phe814Cys, p.Lys913X, p.Ile915Thr) were analyzed for hormone binding, transcriptional activation, cofactor binding, translocation to the nucleus, nuclear dynamics, and structural conformation. Ligand-binding domain variants with low to intermediate transcriptional activation displayed aberrant Kd values for hormone binding and decreased nuclear translocation. Transcriptional activation data, FxxFF-like peptide binding and DNA binding correlated well for all variants, except for p.Arg609Met, p.Leu723Phe and p.Arg775Leu, which displayed a relatively higher peptide binding activity. Variants p.Cys177Gly, p.Asp691del, p.Ala766Ser, p.Phe814Cys, and p.Ile915Thr had intermediate or wild type values in all assays and showed a predominantly nuclear localization in living cells. All transcriptionally inactive variants (p.Arg609Met, p.Leu701Phe, p.Ser741Tyr, p.Arg775Leu, p.Lys913X) were unable to bind to DNA and were associated with complete AIS. Three variants (p.Asp691del, p.Arg775Leu, p.Ile915Thr) still displayed significant functional activities in in vitro assays, although the clinical phenotype was associated with complete AIS. The data show that molecular phenotyping based on 5 different functional assays matched in most (70%) but not all cases.

Expression of 11ß-hydroxysteroid dehydrogenase type 1 in the human hypothalamus.

The hypothalamus is a major target for glucocorticoids and a key structure for hypothalamic-pituitary-adrenal (HPA) axis setpoint regulation. The enzyme 11ß hydroxysteroid dehydrogenase type 1 (11ßHSD1) modulates glucocorticoid signalling in various tissues at the prereceptor level by converting biologically inactive cortisone to its active form cortisol. The present study aimed to assess 11ßHSD1 expression in the human hypothalamus. We studied 11ßHSD1 expression in five frozen and four formalin-fixed, paraffin-embedded human hypothalami (obtained from the Netherlands Brain Bank) by the polymerase chain reaction and immunocytochemistry, respectively. 11ßHSD1 mRNA was expressed in the area of the suprachiasmatic nucleus, which is the biological clock of the brain, in the supraoptic nucleus and paraventricular nucleus (PVN), and in the infundibular nucleus, which is the human homologue of the rodent arcuate nucleus. 11ßHSD1 was detected by immunocytochemistry in the same nuclei. In the PVN, neuronal 11ßHSD1 immunoreactivity colocalised with corticotrophin-releasing hormone (CRH), arginine vasopressin and oxytocin, as shown by dual fluorescence staining. Our data demonstrate that 11ßHSD1 is widely expressed in the human hypothalamus. Its colocalisation with CRH in the PVN suggests a role in modulation of glucocorticoid feedback of the HPA axis, whereas the expression of 11ßHSD1 in additional and functionally diverse hypothalamic nuclei points to a role for the enzyme in the regulation of metabolism, appetite and circadian rhythms.