Showing papers in "Neuroendocrinology in 2010"
TL;DR: It appears that patients with active Cushing’s syndrome do not completely return to their premorbid level of functioning and persistent impairment of quality of life and cognitive function has been reported despite long-term cure.
Abstract: Glucocorticoids are crucial in the initiation and consolidation of the stress response. Patients with active Cushing's syndrome (CS) are exposed to excessive endogenous glucocorticoid levels. In these patients, psychopathology is often being observed. The most common co-morbid disorder is major depression, but to a lesser extent mania and anxiety disorders have also been reported. A severe clinical presentation of CS often also includes depression. Reduction of glucocorticoid synthesis or action, either with metyrapone, ketoconazole, or mifepristone, rather than treatment with antidepressant drugs, is generally successful in relieving depressive symptoms, as well as other disabling symptoms. Following successful surgical treatment of hypercortisolism, both physical and psychiatric signs and symptoms improve substantially. However, it appears that patients do not completely return to their premorbid level of functioning and persistent impairment of quality of life and cognitive function has been reported despite long-term cure. At present, it is not clear whether, and to which extent, psychopathology still affects general well-being after long-term cure of CS.
166 citations
TL;DR: Preliminary data indicate a high proportion of subclinical Cushing’s syndrome in certain risk populations such as patients with type 2 diabetes or osteoporosis and this excess mortality seems confined to patients in whom initial cure was not obtained.
Abstract: Overt Cushing's syndrome is a rare disorder with an annual incidence of 2-3/million of which benign adrenal adenomas account for 0.6/million. The female:male ratio is 3:1. Preliminary data indicate a high proportion of subclinical Cushing's syndrome in certain risk populations such as patients with type 2 diabetes or osteoporosis. The clinical implications of these observations are presently unclear. Surgery remains first line treatment for overt disease and initial cure or remission is obtained in 65-85% of patients with Cushing's disease. Late recurrences, however, occur in up to 20% and the risk does not seem to plateau even after 20 years of follow-up. A 2- to 3-fold increase in mortality is observed in most studies, and this excess mortality seems confined to patients in whom initial cure was not obtained. Cushing's syndrome continues to pose diagnostic and therapeutic challenges and life-long follow-up is mandatory.
155 citations
TL;DR: In humans, a high prevalence (up to 20%) of hepatic steatosis was also reported in patients with Cushing’s syndrome, and mice with a liver-specific disruption of the glucocorticoid receptor had diminished hepatic triglycerides levels.
Abstract: Dyslipidemia seems to be less frequent than other metabolic comorbidities in human Cushing's syndrome. Nevertheless, it plays an important role in determining the global cardiovascular risk in overt and subclinical Cushing's syndrome. In Cushing's syndrome, there is an increase of triglyceride and total cholesterol levels whereas HDL can be at variable levels. Overt and subclinical Cushing's syndrome share many features with metabolic syndrome including insulin resistance, abnormal fasting glucose levels, hypertension, obesity and dyslipidemia. The pathogenetic mechanisms are multifactorial, including direct and indirect cortisol action on lipolysis, free fatty acid production and turnover, very-low-density lipoprotein synthesis and fatty accumulation in the liver. AMP-activated protein kinase mediates many of glucocorticoid-induced metabolic changes. Insulin resistance plays a key role in determining lipid abnormalities. Other hormonal changes are involved including growth hormone, testosterone in men and estrogen in women, catecholamines and cytokines. In vitro, cortisol increases lipoprotein lipase in adipose tissues and particularly in visceral fat where lipolysis is activated, resulting in the release of free fatty acids into the circulation. The increase of free fatty acids may enhance the accumulation of hepatic lipids reducing glucose uptake and activating various serine kinases which results in decreased insulin signaling. Moreover, mice with a liver-specific disruption of the glucocorticoid receptor had diminished hepatic triglycerides levels. In humans, a high prevalence (up to 20%) of hepatic steatosis was also reported in patients with Cushing's syndrome. Genetic variations in the glucocorticoid receptors may also affect the activity of cortisol, lipid metabolism and cardiovascular risk.
150 citations
TL;DR: Gl glucocorticoid excess is able to impair insulin secretion as well as act at the level of the pancreatic beta cells, where it inhibits different steps of the insulin secretion process.
Abstract: Cushing's syndrome is commonly complicated with an impairment of glucose metabolism, which is often clinically manifested as diabetes mellitus. The development of diabetes mellitus in Cushing's syndrome is both a direct and indirect consequence of glucocorticoid excess. Indeed, glucocorticoid excess induces a stimulation of gluconeogenesis in the liver as well as an inhibition of insulin sensitivity both in the liver and in the skeletal muscles, which represent the most important sites responsible for glucose metabolism. In particular, glucocorticoid excess stimulates the expression of several key enzymes involved in the process of gluconeogenesis, with a consequent increase of glucose production, and induces an impairment of insulin sensitivity either directly by interfering with the insulin receptor signaling pathway or indirectly, through the stimulation of lipolysis and proteolysis and the consequent increase of fatty acids and amino acids, which contribute to the development of insulin resistance. Moreover, the peculiar distribution of adipose tissue throughout the body, with the predominance of visceral adipose tissue, significantly contributes to the worsening of insulin resistance and the development of a metabolic syndrome, which participates in the occurrence and maintenance of the impairment of glucose tolerance. Finally, glucocorticoid excess is able to impair insulin secretion as well as act at the level of the pancreatic beta cells, where it inhibits different steps of the insulin secretion process. This phenomenon is probably responsible for the passage from an impairment of glucose tolerance to an overt diabetes mellitus in susceptible patients with Cushing's syndrome.
145 citations
TL;DR: Despite the merits of the PET modality, the CT component must not be neglected and an optimized multiphase CT protocol is recommended.
Abstract: Aim: Retrospective evaluation of the impact of integrated positron emission tomography/computed tomography (PET/CT) using 68Ga-DOTA(0)-Phe(1)-Tyr(3)-octreotide (68
122 citations
TL;DR: Effective treatment of hypercortisolism improves each of the five MetS components, but MetS and carotid atherosclerosis persist in most patients, and the cardiovascular risk therefore remains elevated.
Abstract: Although the concept of metabolic syndrome (MetS) as a disease entity continues to be debated, it provides a means by which patients at risk for diabetes and cardiovascular disease can be identified and categorized with routinely available criteria. Insulin resistance plays a central role in these abnormalities. Risk factors include central obesity, elevated fasting glucose, hypertension, elevated serum triglycerides, and low high-density-lipoprotein cholesterol. Various definitions of MetS have been proposed since 1998. Recently, a joint statement by several major organizations concluded that three abnormal values in a series of five criteria determined whether a person had MetS, and that elevated waist circumference was not an obligatory feature. A single set of cutoff points was proposed, except for waist circumference, which should be defined according to population and ethnic group. Cushing's syndrome (CS) represents an archetype of MetS. High glucocorticoid levels lead to muscle, liver and adipocyte insulin resistance. Almost all patients with CS are obese or overweight, and have abdominal visceral adiposity. Many also have glucose metabolism abnormalities (21-60% and 20-47% of the patients have impaired glucose tolerance and diabetes, respectively), hypertension (more than 70% of the patients), and elevated triglyceride levels (20% of the patients). Almost two thirds of CS patients fulfill at least three criteria for MetS. The elevated incidence of diabetes and premature atherosclerosis (directly related to the length of exposure to hypercortisolism), and the increased mortality (particularly cardiovascular mortality) relative to the general population (2 to 4 times higher) show that the predictive value of MetS is also valid in CS. Effective treatment of hypercortisolism improves each of the five MetS components, but MetS and carotid atherosclerosis persist in most patients, and the cardiovascular risk therefore remains elevated. This calls for aggressive treatment of comorbidities and for very long-term follow-up.
109 citations
TL;DR: It is proposed that the kisspeptin system plays a central role in integrating a range of metabolic inputs, thus constituting the link between energy status with the hypothalamic-pituitary-gonadal axis, and put forward potential clinical studies to test the hypothesis.
Abstract: Hypogonadism occurs commonly in men with type 2 diabetes (T2DM) and severe obesity. Current evidence points to a decreased secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus and thereby decreased secretion of gonadotropins from the pituitary gland as a central feature of the pathophysiology in these men. Hyperglycaemia, inflammation, leptin and oestrogen-related feedback have been proposed to make aetiological contributions to the hypogonadotropic hypogonadism of T2DM. However, the neuroendocrine signals that link these factors with modulation of GnRH neurons have yet to be identified. Kisspeptins play a central role in the modulation of GnRH secretion and, thus, downstream regulation of gonadotropins and testosterone secretion in men. Inactivating mutations of the kisspeptin receptor have been shown to cause hypogonadotropic hypogonadism in man, whilst an activating mutation is associated with precocious puberty. Data from studies in experimental animals link kisspeptin expression with individual factors known to regulate GnRH secretion, including hyperglycaemia, inflammation, leptin and oestrogen. We therefore hypothesise that decreased endogenous kisspeptin secretion is the common central pathway that links metabolic and endocrine factors in the pathology of testosterone deficiency seen in men with obesity and T2DM. We propose that the kisspeptin system plays a central role in integrating a range of metabolic inputs, thus constituting the link between energy status with the hypothalamic-pituitary-gonadal axis, and put forward potential clinical studies to test the hypothesis.
101 citations
TL;DR: In Cushing’s disease, combination therapy with drugs that target the corticotropic adenoma, i.e. the universal somatostatin analogue pasireotide and/or the dopamine agonist cabergoline, and low-dose ketoconazole seems a rational approach to achieve biochemical control.
Abstract: Cushing's syndrome is associated with serious morbidity and increased mortality. Irrespective of its cause, i.e. a pituitary adenoma, ectopic ACTH production or an adrenal neoplasia, Cushing's syndrome is primarily treated surgically. However, when surgery is unsuccessful or contraindicated, medical therapy is needed to treat hypercortisolism. The spectrum of available drugs includes adrenal-blocking agents, neuromodulatory drugs and glucocorticoid receptor antagonists. Adrenal blocking drugs suppress adrenal cortisol production via inhibition of steroidogenic enzymes. Ketoconazole and metyrapone are most frequently used for this purpose, but chronic treatment with these drugs can be limited by side effects like hepatotoxicity (ketoconazole) and increased androgen and mineralocorticoid production (metyrapone). Etomidate can be used to rapidly reverse cortisol excess in patients with acute complications of (severe) hypercortisolism like psychosis. In Cushing's disease, combination therapy with drugs that target the corticotropic adenoma, i.e. the universal somatostatin analogue pasireotide and/or the dopamine agonist cabergoline, and low-dose ketoconazole seems a rational approach to achieve biochemical control.
85 citations
TL;DR: Considering that remission from hypercortisolism is often difficult to achieve and that the cardiovascular risk can persist even during disease remission, care and control of all cardiovascular risk factors should be one of the primary goals during the follow-up of patients with CS.
Abstract: Cushing's syndrome (CS) causes metabolic abnormalities that determine an increased cardiovascular risk not only during the active phase of the disease but also for a long time after cure. Cardiovascular complications, such as premature atherosclerosis, coronary artery disease, heart failure, and stroke, in patients with CS cause a mortality rate higher than that observed in a normal population. The increased cardiovascular risk is mainly due to metabolic complications, such as metabolic syndrome, but also to vascular and cardiac alterations such as atherosclerosis and cardiac structural and functional changes. In the clinical management of patients with CS the focus should be on identifying the global cardiovascular risk and the aim should be to control not only hypertension but also other correlated risk factors, such as obesity, glucose intolerance, insulin resistance, dyslipidemia, endothelial dysfunction and the prothrombotic state. Considering that remission from hypercortisolism is often difficult to achieve and that the cardiovascular risk can persist even during disease remission, care and control of all cardiovascular risk factors should be one of the primary goals during the follow-up of these patients.
84 citations
TL;DR: Detailed study of these patients has highlighted the emerging theme of oligogenicity and genotypic synergism, and also expanded the phenotypic diversity with the documentation of reversal of GnRH deficiency later in adulthood in some patients.
Abstract: Evolutionary survival of a species is largely a function of its reproductive fitness. In mammals, a sparsely populated and widely dispersed network of hypothalamic neurons, the gonadotropin-releasing hormone (GnRH) neurons, serve as the pilot light of reproduction via coordinated secretion of GnRH. Since it first description, human GnRH deficiency has been recognized both clinically and genetically as a heterogeneous disease. A spectrum of different reproductive phenotypes comprised of congenital GnRH deficiency with anosmia (Kallmann syndrome), congenital GnRH deficiency with normal olfaction (normosmic idiopathic hypogonadotropic hypogonadism), and adult-onset hypogonadotropic hypogonadism has been described. In the last two decades, several genes and pathways which govern GnRH ontogeny have been discovered by studying humans with GnRH deficiency. More importantly, detailed study of these patients has highlighted the emerging theme of oligogenicity and genotypic synergism, and also expanded the phenotypic diversity with the documentation of reversal of GnRH deficiency later in adulthood in some patients. The underlying genetic defect has also helped understand the associated nonreproductive phenotypes seen in some of these patients. These insights now provide practicing clinicians with targeted genetic diagnostic strategies and also impact on clinical management.
82 citations
TL;DR: The development of a mathematically validated nomogram provides a platform for objective assessment of SI NET disease, a finite basis for precise prognostication and a tool to guide management strategy.
Abstract: Neuroendocrine tumors (NETs) are a heterogeneous group of cancers of which the commonest site is the small intestine (SI). Most information available to determine tumor behavior reflects univariate as
TL;DR: This study points out to the complex regulation of VEGF synthesis and secretion in neoplastic GEP endocrine cells and suggests that the inhibition of V EGF production by octreotide and rapamycin may contribute to their therapeutic effects.
Abstract: Gastroenteropancreatic (GEP) endocrine tumors are hypervascular tumors able to synthesize and secrete high amounts of VEGF. We aimed to study the regulation of VEGF production in GEP endocrine tumors and to test whether some of the drugs currently used in their treatment, such as somatostatin analogues and mTOR inhibitors, may interfere with VEGF secretion. We therefore analyzed the effects of the somatostatin analogue octreotide, the mTOR inhibitor rapamycin, the PI3K inhibitor LY294002, the MEK1 inhibitor PD98059 and the p38 inhibitor SB203850 on VEGF secretion, assessed by ELISA and Western blotting, in three murine endocrine cell lines, STC-1, INS-r3 and INS-r9. Octreotide and rapamycin induced a significant decrease in VEGF production by all three cell lines; LY294002 significantly inhibited VEGF production by STC-1 and INS-r3 only. We detected no effect of PD98059 whereas SB203850 significantly inhibited VEGF secretion in INS-r3 and INS-r9 cells only. By Western blotting analysis, we observed decreased intracellular levels of VEGF and HIF-1alpha under octreotide, rapamycin and LY294002. For rapamycin and LY294002, this effect was likely mediated by the inhibition of the mTOR/HIF-1/VEGF pathway. In addition to its well-known anti-secretory effects, octreotide may also act through the inhibition of the PI3K/Akt pathway, as suggested by the decrease in Akt phosphorylation detected in all three cell lines. In conclusion, our study points out to the complex regulation of VEGF synthesis and secretion in neoplastic GEP endocrine cells and suggests that the inhibition of VEGF production by octreotide and rapamycin may contribute to their therapeutic effects.
TL;DR: Treating hypertension in Cushing’s syndrome remains a difficult task and a big challenge, in order to decrease the morbidity and mortality associated with the disease.
Abstract: Hypertension is one of the most distinguishing features of endogenous Cushing’s syndrome (CS), as it is present in about 80% of adult patients whereas in children its prevalence is about 47%. Hyperten
TL;DR: ENETS consensus guidelines for the management of brain, cardiac and ovarian metastases from neuroendocrine tumors and their implications for clinical practice are published.
Abstract: ENETS consensus guidelines for the management of brain, cardiac and ovarian metastases from neuroendocrine tumors
TL;DR: ENETS consensus guidelines for the management of bone and lung metastases from neuroendocrine tumors and their implications for clinical practice are published.
Abstract: ENETS consensus guidelines for the management of bone and lung metastases from neuroendocrine tumors
TL;DR: Investigation of early and late results of TS for CD and evaluation of various postoperative tests in order to predict the outcome of TS found CRH and/or metyrapone testing are not superior to morning cortisol concentration in the prediction of outcome ofTS.
Abstract: Objective: Transsphenoidal surgery (TS) is the primary therapy for Cushing’s disease (CD). The aims of this retrospective study were twofold: (i) investigate early and late results
TL;DR: Results show that ERα in the VMN is crucial for the entire sequence of behavioral events from the processes leading to the establishment of sexual contact until the accomplishment of copulatory behaviors.
Abstract: The display of copulatory behaviors usually requires the presence of a mate and is, therefore, preceded by a search for and approach to a potential partner. The intensity of approach behaviors is determined by a process labeled sexual incentive motivation. Although it is known that female sexual motivation depends on estrogens, their site of action within the brain is unknown. In the present experiment, we obtained data relevant to this issue. An shRNA encoded within an adeno-associated viral (AAV) vector directed against the estrogen receptor α (ERα) gene (or containing a nonsense base sequence as a control treatment) was injected bilaterally into the ventromedial nucleus of the hypothalamus (VMN) or the posterodorsal amygdala (MePDA) of female rats. After an 80% reduction of the number of ERα in the VMN, sexual incentive motivation was absent after treatment with estradiol and progesterone. Proceptivity and receptivity were also much reduced, while the number of rejections was enhanced. Suppression of the ERα in the MePDA lacked these effects. Likewise, the inactive control AAV vector failed to modify any behavior. Thus, the ERα in the VMN, but not in the MePDA, is important for proceptivity and receptivity as well as for sexual incentive motivation. These results show that ERα in the VMN is crucial for the entire sequence of behavioral events from the processes leading to the establishment of sexual contact until the accomplishment of copulatory behaviors.
TL;DR: NF-CPETs have a measurable propensity to be benign and in those patients affected by small and asymptomatic NF- CPET a more conservative surgical approach or a follow-up policy could be considered.
Abstract: Background: Cystic pancreatic endocrine tumors (CPETs) are rare lesions and their biological features have been scarcely investigated. Aim: To compare clinical an
TL;DR: Patients with active CS should be treated as having a prothrombotic disorder and undergo antithromBotic prophylaxis during IPS sampling and low-dose heparin treatment early after surgery should be suggested.
Abstract: A hypercoagulable state and its consequent increased incidence of thromboembolic complications are reported in patients with Cushing's syndrome (CS). These alterations are related to cortisol excess that induces prothrombotic changes in blood by several and complex mechanisms including increased levels of clotting factors, mainly factor VIII and von Willebrand factor (VWF) and impaired fibrinolytic capacity. However, it has recently been observed that the increase in VWF levels is not a constant feature of CS and that VWF response to glucocorticoids is genetically determined and depends on the presence of particular polymorphisms in the VWF gene promoter. The risk of venous thromboembolism is moreover enhanced in patients with CS by additional endogenous and exogenous risk factors such as obesity, bed rest, surgery and invasive diagnostic procedures like inferior petrosal sinus (IPS) sampling. In line with all these data, patients with active CS should be treated as having a prothrombotic disorder and undergo antithrombotic prophylaxis during IPS sampling. Special care should be taken in the immediate perioperative period in order to avoid thromboembolic events. In the absence of prospective randomized trials, preventive antithrombotic treatment (best with heparin) during IPS sampling and low-dose heparin treatment early after surgery should be suggested.
TL;DR: These studies provide direct evidence for a functional circadian clock in native GnRH neurons with a phase that closely follows that of the SCN.
Abstract: Although it is generally accepted that the circadian clock provides a timing signal for the luteinizing hormone (LH) surge, mechanistic explanations of this phenomenon remain underexplored. It is known, for example, that circadian locomotor output cycles kaput (clock) mutant mice have severely dampened LH surges, but whether this phenotype derives from a loss of circadian rhythmicity in the suprachiasmatic nucleus (SCN) or altered circadian function in gonadotropin-releasing hormone (GnRH) neurons has not been resolved. GnRH neurons can be stimulated to cycle with a circadian period in vitro and disruption of that cycle disturbs secretion of the GnRH decapeptide. We show that both period-2 (PER2) and brain muscle Arnt-like-1 (BMAL1) proteins cycle with a circadian period in the GnRH population in vivo. PER2 and BMAL1 expression both oscillate with a 24-hour period, with PER2 peaking during the night and BMAL1 peaking during the day. The population, however, is not as homogeneous as other oscillatory tissues with only about 50% of the population sharing peak expression levels of BMAL1 at zeitgeber time 4 (ZT4) and PER2 at ZT16. Further, a light pulse that induced a phase delay in the activity rhythm of the GnRH-eGFP mice caused a similar delay in peak expression levels of BMAL1 and PER2. These studies provide direct evidence for a functional circadian clock in native GnRH neurons with a phase that closely follows that of the SCN.
TL;DR: The value of 123I-MIBG scintigraphy is high in familial syndromes with multiple neuroendocrine tumors at different sites, multifocal tumors, and relapsing and metastatic disease and remains important in pheochromocytoma and functioning neuro endocrine tumors.
Abstract: Aim: The aim of the study was to evaluate the current role of 123I-MIBG scintigraphy in the detection and follow-up of patients with paragangliomas. Materials an
TL;DR: The lack of a large available prospective cohort of patients on mifepristone, and the scarcity of data on its long-term effects, does not allow recommending it as a first-line drug in the treatment of hypercortisolism, however, as mifEPristone is a rapidly effective drug, it can play a role in the management of hyperCushing's syndrome.
Abstract: Mifepristone is the first and only available glucocorticoid receptor antagonist. It was initially mainly considered as a so-called 'contragestive' pill due to its antiprogestin activity. In this review, we summarize the results of mifepristone reported in the literature as a treatment of Cushing's syndrome. Most of the patients were treated due to unsuccessful surgery and/or partially effective anticortisolic drugs. The majority of them presented a rapid decrease of clinical signs of hypercortisolism during the first month of treatment; about half experienced a reduction in their elevated blood pressure, and half of the diabetic patients presented improved blood glucose levels. Mifepristone treatment has 2 main drawbacks: (1) the blockade of glucocorticoid receptors leads to increased ACTH and cortisol levels, making it difficult to adapt the treatment and diagnose adrenal deficiency, and (2) increased cortisol levels can also lead to severe hypokalemia. Follow-up of efficacy should only be clinical (weight, blood pressure, skin lesions) and biological (regular blood potassium sampling). Dose adjustment will be performed based on these parameters. The lack of a large available prospective cohort of patients on mifepristone, and the scarcity of data on its long-term effects, does not allow recommending it as a first-line drug in the treatment of hypercortisolism. However, as mifepristone is a rapidly effective drug, it can play a role in the management of hypercortisolism. The main indication is the partial efficacy or bad tolerance of other well-known anticortisolic drugs, either by replacement (bad tolerance, lack of effectiveness) or addition (multimodal approach) of mifepristone.
TL;DR: Bone mineral density measurement at the lumbar spine should be performed as a screening test in all patients with CS due to the preferential loss of trabecular bone induced by GCs, and Bisphosphonates can induce a more rapid improvement in BMD than cortisol normalization alone and can be used in patients with increased risks for further fractures and/or persistent hypercortisolemia to prevent further bone loss.
Abstract: Structural and functional impairment of the skeletal system remains an important cause of morbidity and disability in patients with Cushing's syndrome (CS). Glucocorticoid (GC) excess inhibits bone formation and calcium absorption from the gut, increases bone resorption, and alters the secretion of gonadotropin and growth hormones, cytokines and growth factors influencing bone. Both overt and subtle endogenous hypercortisolism affect bone, leading to vertebral fractures in up to 70% of patients. Fracture risk is related to age at onset, duration and severity of the disease and individual susceptibility to GCs that is genetically determined. Bone mineral density (BMD) measurement at the lumbar spine should be performed as a screening test in all patients with CS due to the preferential loss of trabecular bone induced by GCs. The higher risk of fractures at comparable BMD values with controls suggests that bone quality features, not assessed by routine BMD approaches, are also important and should be addressed when indicated applying specific radiological means. Successful treatment of GC excess is associated with improvement in bone mass which, although delayed and often incomplete, reduces the risk of osteoporotic fractures. Bisphosphonates can induce a more rapid improvement in BMD than cortisol normalization alone and can be used in patients with increased risks for further fractures and/or persistent hypercortisolemia to prevent further bone loss. Anabolic agents have not as yet been systemically used. Avascular necrosis, mainly of the femoral neck, and growth arrest in children are the most common skeletal disorders unrelated to osteoporosis encountered in patients with endogenous hypercortisolism.
TL;DR: Leptin corrects the hypogonadotropic state in the lean condition by upregulation of POMC gene expression, and may increase transport and acetylation of melanocortins to target cells in the brain.
Abstract: Background/Aims: Leptin restores gonadotropic function in lean hypogonadotropic animals by an unknown mechanism. We aimed to test the hypothesis that restoration of gonadotropic fun
TL;DR: ENETS Consensus Guidelines for the Management of Peritoneal Carcinomatosis from Neuroendocrine Tumors are published.
Abstract: ENETS Consensus Guidelines for the Management of Peritoneal Carcinomatosis from Neuroendocrine Tumors
TL;DR: It is demonstrated that circulating estradiol stimulates the synthesis of progesterone in adult hypothalamic astrocytes, and this neuroprogesterone is critical for initiating the LH surge.
Abstract: Astrocytes are the most abundant cells in the central nervous system (CNS). It appears that astrocytes are as diverse as neurons, having different phenotypes in various regions throughout the brain and participating in intercellular communication that involves signaling to neurons. It is not surprising then that astrocytes in the hypothalamus have an active role in the CNS regulation of reproduction. In addition to the traditional mechanism involving ensheathment of neurons and processes, astrocytes may have a critical role in regulating estrogen-positive feedback. Work in our laboratory has focused on the relationship between circulating estradiol and progesterone synthesized de novo in the brain. We have demonstrated that circulating estradiol stimulates the synthesis of progesterone in adult hypothalamic astrocytes, and this neuroprogesterone is critical for initiating the LH surge. Estradiol cell signaling is initiated at the cell membrane and involves the transactivation of metabotropic glutamate receptor type 1a (mGluR1a) leading to the release of intracellular stores of calcium. We used surface biotinylation to demonstrate that estrogen receptor-α (ERα) is present in the cell membrane and has an extracellular portion. Like other membrane receptors, ERα is inserted into the membrane and removed via internalization after agonist stimulation. This trafficking is directly regulated by estradiol, which rapidly and transiently increases the levels of membrane ERα, and upon activation, increases internalization that finally leads to ERα degradation. This autoregulation temporally limits membrane-initiated estradiol cell signaling. Thus, neuroprogesterone, the necessary signal for the LH surge, is released when circulating levels of estradiol peak on proestrus and activate progesterone receptors whose expression has been induced by the gradual rise of estradiol during follicular development.
TL;DR: Where it was possible to analyse contributing factors to mortality, the presence of hypertension and diabetes mellitus, in addition to persistence of hypercortisolism, was shown to be significant and it remains possible that an overall SMR in ‘cured’ patients would be significant given a larger cohort, followed for longer, and with more deaths.
Abstract: The causes of premature death in untreated Cushing's syndrome are vascular disease (myocardial infarction/stroke), uncontrolled diabetes mellitus and complications and infections. Long-term mortality outcome studies on pituitary-dependent Cushing's disease (CD) are limited to six studies in the English language literature. This paper reviews these studies on CD, other causes of Cushing's syndrome being excluded, because CD represents 80% of patients with the syndrome. The period covered by these studies (1970-1990) is when transsphenoidal surgery was well established as primary treatment for CD. Two studies were exclusively from surgical centres and are likely biased in favour of surgically resectable adenomas, so this needs to be borne in mind when interpreting their results. The criteria for remission of hypercortisolism and persistent disease were variable. The overall number of patients in each report is small, and the number of deaths even smaller by epidemiological standards giving very wide confidence intervals to the standardised mortality ratios (SMR). Moreover, follow-up time was relatively short (median 10-12 years) for a disease diagnosed in the patients' late 30s. Notwithstanding the above limitations of retrospective studies, and potential for positive bias, the overall SMR of around 1.5 was not significantly different from the relevant normal population for those patients deemed in remission. However, SMR was significantly worse for those patients with persistent disease. Where it was possible to analyse contributing factors to mortality, the presence of hypertension and diabetes mellitus, in addition to persistence of hypercortisolism, was shown to be significant. It remains possible that an overall SMR in 'cured' patients would be significant given a larger cohort, followed for longer, and with more deaths. What is clearly required is a multicentre prospective cohort study with >30 years' follow-up to answer the question definitively and identify the contributing factors in detail in order to achieve optimum long-term outcome.
TL;DR: Addition of cabergoline to octreotide was effective in both short- and long-term control of IGF-I in acromegaly, especially in patients with mild/moderately elevated GH/IGF-I levels duringOctreotide.
Abstract: Objective: Nearly 40% of acromegalic patients fail to control GH/IGF-I levels with somatostatin analogues (SA). Dopaminergic agonists (DA) are even less effective, but combination t
TL;DR: Preliminary results from a study on 17 patients with Cushing's disease suggest that the combined use of pasireotide, cabergoline and low-dose ketoconazole may have additive beneficial effects in the medical treatment of Cushing’s disease.
Abstract: Cushing's disease is Cushing's syndrome caused by an adrenocorticotropic hormone-secreting pituitary adenoma and, in the absence of adequate treatment, can be fatal. Cushing's disease represents an unmet medical need, with no approved medical therapies. Pasireotide is a novel multi-receptor-targeted somatostatin analogue with high affinity for sst(1,2,3) and sst(5). Compared with octreotide, pasireotide has an in vitro binding affinity 40-, 30- and 5-fold higher for sst(5,) sst(1) and sst(3), respectively, and 2-fold lower for sst(2). Adrenocorticotropic hormone-secreting pituitary adenomas predominantly express sst(5), followed by sst(2) and sst(1), suggesting that pasireotide may be effective in the treatment of Cushing's disease. In a 15-day phase II trial of pasireotide 600 μg s.c. b.i.d. in patients with de novo or persistent/recurrent Cushing's disease, 22 of 29 patients (76%) achieved reduced urinary free cortisol (UFC) levels, 5 of whom (17%) achieved normalized UFC. Patients who achieved normalized UFC had a significantly greater reduction in serum cortisol than those who did not (p = 0.04), and minimum pasireotide plasma concentrations appeared to be higher in responders. Based on these results, a randomized, double-blind phase III study comparing pasireotide 600 μg b.i.d. and 900 μg b.i.d. was initiated and is ongoing. This is the largest ever phase III study in patients with Cushing's disease. The primary end point of this study is normalization of UFC after 6 months of treatment. Finally, preliminary results from a study on 17 patients with Cushing's disease suggest that the combined use of pasireotide, cabergoline and low-dose ketoconazole may have additive beneficial effects in the medical treatment of Cushing's disease.
TL;DR: The most effective means of control of diabetes mellitus in a patient with active Cushing’s syndrome is to lower the levels of circulating cortisol, which may initially be achieved by using adrenal steroidogenesis blockade with drugs including metyrapone, ketaconazole, or, on occasion, mitotane.
Abstract: Active Cushing's syndrome is associated with insulin resistance induced by the high and prolonged circulating level of glucocorticoids. In endogenous Cushing's syndrome the overall incidence of diabetes mellitus and insulin resistance is very likely to be under-reported as not all patients are actively investigated with glucose tolerance tests. Whilst it is common clinical experience that management of diabetes mellitus is necessary in patients with Cushing's syndrome there is a dearth of literature-based evidence to support which regimes are the most effective. Therefore, a pragmatic approach is necessary on an individualized patient basis, whereby patients are stratified according to the severity of their impaired glucose homeostasis. The most effective means of control of diabetes mellitus in a patient with active Cushing's syndrome is to lower the levels of circulating cortisol. This may initially be achieved by using adrenal steroidogenesis blockade with drugs including metyrapone, ketaconazole, or, on occasion, mitotane. The rapid action of metyrapone is particularly suitable in this circumstance. Despite this, diabetes-specific therapy is often necessary and metformin and PPAR-γ agonists may be of use, but in the acute setting insulin therapy is frequently needed. Definitive management directed against source driving Cushing's syndrome is often highly effective at either reducing the severity of diabetes, or allowing its complete resolution. Patients experiencing diabetes mellitus in the context of exogenously administered glucocorticoids may well require insulin therapy for the period that the high levels of steroids are being administered. Despite resolution of Cushing's syndrome after definitive treatment patients may continue to exhibit insulin resistance. This and other cardiovascular risk factors require ongoing and long-term attention.