Comparison of adipose tissue derived genes in endogenous Cushing's syndrome versus diet-induced obesity.

INTRODUCTION: Dysregulation of adipokine secretion and action is a characteristic feature of obesity and a key clinical feature of Cushing's syndrome (CS). We have investigated whether endogenous glucocorticoid excess influences adipose tissue-derived gene expression. MATERIAL AND METHODS: mRNA expression of adipokines; adiponectin, resistin, tumour necrosis factor-a, interleukin-6 (IL-6), angiotensinogen (AGT), plasminogen activator inhibitor type 1, retinol binding protein 4, visfatin, and cystatin C was assessed by quantitative real-time RT-PCR in visceral adipose tissue removed during abdominal surgery of eight patients with CS, and six control patients. RESULTS: We did not find any significant difference in the investigated genes; however, the almost significant overexpression of AGT and underexpression of IL-6 might be noteworthy (p = 0.06 in both cases). CONCLUSIONS: No significant differences were found in the expression of the investigated genes known as cardiometabolic risk factors. This indicates that there are no major differences between endogenous hypercortisolism or diet-induced obesity regarding the expression of adipokines involved in cardiometabolic disorders. However, the difference in AGT and IL-6 expression might be included in pathways affecting fat distribution in CS.

ACTH-secreting Crooke cell carcinoma of the pituitary.

PURPOSE: While pituitary adenomas are common, pituitary carcinomas are rare. It is unclear whether pituitary carcinomas arise de novo or evolve from adenomas. METHODS: We studied the clinical characteristics and tissue samples from eight pituitary surgeries and the autopsy from a patient with pituitary carcinoma. A 16-year-old female patient was diagnosed with an aggressive Crooke cell macroadenoma. Following transsphenoidal surgery, clinical signs of Cushing disease quickly reappeared. During the 14-year course of the illness, eight pituitary surgeries, three courses of extracranial irradiation and two (90) Yttrium-DOTATOC treatments were undertaken. A bilateral adrenalectomy was performed. The patient died of metastatic disease and uncontrolled hypercortisolism due to an adrenal remnant. A systematic morphologic study (histologic staining, electron microscopy) of all available surgical and autopsy specimens was undertaken. RESULTS: Brisk mitotic activity, high Ki-67 and p53 immunolabelling were present in the pituitary samples from the onset. High proportion of tumour cells showed irregular nuclei and large nucleoli, and gradual increase in MGMT staining was observed. The tumour remained of Crooke cell type throughout the course. Autopsy disclosed a postirradiation sarcoma in the pituitary area. CONCLUSIONS: The question whether pituitary carcinomas arise de novo or transform from an adenoma cannot be answered at present with certainty.

[Consensus on the change of criteria for cure of acromegaly during the last decade]. / Konszenzus a kritériumok változásáról az acromegalia gyógyulásának megítélésében - nemzetközi ajánlás, 2010.

The Acromegaly Consensus Group redefined the consensus criteria for cure of acromegaly. 74 neurosurgeons and experienced endocrinologists summarized the latest results on diagnosis and treatment of acromegaly. In this consensus statement the reliable growth hormone and insulin-like growth factor-1 assays were established. Definition of disease control was discussed based on the available publications and evidence. This short communication summarizes the clinical aspects of consensus criteria for diagnosis and cure of acromegaly based on the original article.

[Growth hormone receptor antagonist in the treatment of acromegaly]. / Növekedésihormonreceptor-antagonista alkalmazásának lehetoségei acromegaliában.

Exploration of construction, function and interaction of human growth hormone and growth hormone receptor in details resulted in the innovation of the new growth hormone receptor antagonist, pegvisomant. Pegvisomant with different mechanism of action extended the tools of medical management of acromegaly. Importance of the novel treatment modality is high. In one hand the necessity of the strict control of growth hormone/insulin-like growth factor-I axis has been proven regarding the mortality of the disease. On the other hand, despite the use of all current modes of treatment (surgery, radiotherapy, dopamine agonists, somatostatin analogs), a significant cohort of patients with acromegaly remains inadequately controlled. Pegvisomant has been registered in 2004. Since 2006, it has been used in Hungary for the treatment of acromegaly in patients who have had an inadequate response to surgery and/or radiation therapy and/or other medical therapies, or for whom these therapies are not appropriate. Clinical use of pegvisomant in the treatment of acromegaly is effective, well tolerated, and safe, based on international Acrostudy database. In order to improve the efficacy of therapy clinical trials started with pegvisomant and somatostatin analog combination treatment. Evidence of several further effects of the growth hormone/insulin-like growth factor-I axis suggests other potential uses of growth hormone receptor antagonists.

[Familial isolated pituitary adenoma syndrome]. / Familiáris izolált hypophysisadenoma.

Familial pituitary adenomas occur in multiple endocrine neoplasia type 1, Carney complex, as well as in familial isolated pituitary adenoma syndrome. Familial isolated pituitary adenoma syndrome is an autosomal dominant disease with incomplete penetrance. Pituitary adenomas occur in familial setting but without any other specific tumors. In 20-40% of families with this syndrome, mutations have been identified in the aryl hydrocarbon receptor interacting protein gene while in the rest of the families the causative gene or genes have not been identified. Families carrying aryl hydrocarbon receptor interacting protein gene mutations have a distinct phenotype with younger age at diagnosis and a predominance of somatotroph and lactotroph adenomas. Germline mutations of the aryl hydrocarbon receptor interacting protein gene can be occasionally identified in usually young-onset seemingly sporadic cases. Genetic and clinical testing of relatives of patients with aryl hydrocarbon receptor interacting protein gene mutations can lead to earlier diagnosis and treatment at an earlier stage of the pituitary tumor.

[Treatment of acromegaly]. / Az acromegalia kezelése.

Growth hormone (GH) hypersecretion leads to acromegaly which is associated with several co-morbidities and increased mortality. Despite of the typical clinical features and modern diagnostic tools, it often takes years from the onset of the disease until the diagnosis. The aims of the treatment are to reduce or control the tumor growth, inhibit the GH hypersecretion, normalize the insulin-like growth factor-I (IGF-I) levels, treat the co-morbidities and therefore reduce mortality. There are three approaches for therapy: surgery, medical management (dopamine agonist, somatostatin analogues and GH receptor antagonist), and radiotherapy. Efficient therapy of the disease is based on the appropriate multidisciplinary team management.

Differential ligand-mediated pituitary somatostatin receptor subtype signaling: implications for corticotroph tumor therapy.

OBJECTIVE: Pituitary targeted pharmacotherapy for Cushing's disease is challenging and ineffective. Unlike octreotide and lanreotide, the multisomatostatin receptor (SST) analog pasireotide that exhibits SST5 greater than SST2 binding affinity offers potential for treating Cushing's disease. Because corticotroph cells express SST5 more abundantly than SST2, pasireotide likely exerts superior corticotroph action mainly through SST5. However, there is no direct evidence for this assumption, and moreover, the ligand effect on corticotroph SST2 is not known. RESULTS: We used AtT20 mouse pituitary corticotroph tumor cells stably overexpressing SST2 or SST5 and TtT/GF mouse pituitary folliculostellate cells stably or transiently expressing SST receptors to examine ligand-receptor activation by SST2- and SST5-selective agonists. We show that pasireotide was more potent than either octreotide or somatostatin-14 in mouse corticotroph cells. Pasireotide potency is not affected by SST2 abundance, SST2 antagonist treatment, or octreotide cotreatment in SST2-overexpressing cells. Pasireotide also does not induce SST2 internalization and attenuates octreotide or SRIF14-induced SST2 internalization only at superphysiological dose ranges. In contrast, octreotide attenuates pasireotide potency in SST5-overexpressing cells. Moreover, short exposure to pasireotide causes prolonged inhibition of forskolin or CRH-induced cAMP accumulation, in contrast to somatostatin-14- and SST2-selective agonists that induced postwithdrawal cAMP rebound. Long-term pasireotide signaling effects are enhanced by SST5 overexpression. CONCLUSION: The results indicate that SST5 determines short- and long-term enhanced pasireotide action in corticotroph cells, whereas the ligand action on SST2 is negligible.

Somatostatin analogues stimulate p27 expression and inhibit the MAP kinase pathway in pituitary tumours.

OBJECTIVES: Somatostatin (SST) analogues play an important role in the medical management of somatotroph pituitary adenomas and new agonists have the potential to be effective in a wider group of pituitary and other tumours. The anti-proliferative effect of SST occurs through multiple mechanisms, one of which is cell-cycle arrest, where p27, a cyclin-dependent kinase inhibitor, is an important regulator. We hypothesised that SST may upregulate p27 protein levels and downregulate the MAP kinase pathway in these tumours. METHODS: Human pituitary adenoma cells and rat pituitary cell line (GH3) were cultured and treated in vitro with octreotide and the broad-spectrum SST agonist SOM230 (pasireotide). Immunoblotting for p27 and phospho-ERK (pERK) was performed and proliferation assessed by [3H]-thymidine incorporation. Histological samples from acromegalic patients treated with octreotide before surgery were immunostained for p27 and compared to samples from untreated patients matched for sex, age, tumour size, extension and invasiveness. RESULTS: We detected upregulation of p27 protein levels with SST analogue treatment in vitro in human pituitary adenoma samples. pERK1/2 was inhibited by SST analogues in both the human samples and GH3 cells. SST and its analogues inhibited the proliferation of GH3 cells. p27 immunostaining was stronger in samples from patients with longer preoperative octreotide treatment (more than 6 months) than in samples from patients with shorter treatment periods. CONCLUSIONS: This study demonstrates that SST-mediated growth inhibition is associated with the downregulation of pERK and upregulation of p27. More potent and broader-spectrum SST analogues are likely to play an increasing role in the treatment of tumours, where the MAP kinase pathway is overactivated.

[Ghrelin--a hormone with multiple functions]. / Ghrelin: a többfunkciós hormon.

The growth hormone secretagogue ghrelin is in the centre of interest since its discovery in 1999. It stimulates growth hormone, corticotropic hormone and prolactin secretion, but also plays an important role in the regulation of appetite, carbohydrate- and lipid metabolism and possibly on gastric acid secretion, gastric motility, heart function and as well as immune functions and cell proliferation. Ghrelin was originally identified from the stomach but it is also present in all tissue among others in: hypothalamus, pituitary, pancreas, lung, immune cells, placenta, ovary, testis, kidney and in different tumours including pituitary adenoma, neuroendocrine tumours, thyroid carcinomas, endocrine tumours of the pancreas and lung. The gene structure and its receptor are similar to motilin, they are both synthesized in the upper gastrointestinal tract and both have prokinetic activity on gut motility. The ghrelin receptor (growth hormone secretagogue receptor) is a member of G protein-coupled seven transmembrane domain receptor. The receptor is localised in the central nervous system, kidney, thyroid, pancreas, myocardium and spleen. Starvation and low body mass index decrease, while food intake, hyperglycaemia, elevated insulin levels and high body mass index increase the endogenous ghrelin levels. Although we know much about the ghrelin, number of questions remain unanswered, such as the effects of the locally-produced ghrelin or its role in the cell metabolism.

Cannabinoids and ghrelin have both central and peripheral metabolic and cardiac effects via AMP-activated protein kinase.

Endocannabinoids and ghrelin are potent appetite stimulators and are known to interact at a hypothalamic level. However, both also have important peripheral actions, including beneficial effects on the ischemic heart and increasing adipose tissue deposition, while ghrelin has direct effects on carbohydrate metabolism. The AMP-activated protein kinase (AMPK) is a heterotrimeric enzyme that functions as a fuel sensor to regulate energy balance at both cellular and whole body levels, and it may mediate the action of anti-diabetic drugs such as metformin and peroxisome proliferator-activated receptor gamma agonists. Here we show that both cannabinoids and ghrelin stimulate AMPK activity in the hypothalamus and the heart, while inhibiting AMPK in liver and adipose tissue. These novel effects of cannabinoids on AMPK provide a mechanism for a number of their known actions, such as the reduction in infarct size in the myocardium, an increase in adipose tissue, and stimulation of appetite. The beneficial effects of ghrelin on heart function, including reduction of myocyte apoptosis, and its effects on lipogenesis and carbohydrate metabolism, can also be explained by its ability to activate AMPK. Our data demonstrate that AMPK not only links the orexigenic effects of endocannabinoids and ghrelin in the hypothalamus but also their effects on the metabolism of peripheral tissues.

Low level of cyclin D1 protein expression in thyroid microcarcinomas from an autopsy series.

In a recent epidemiological screening study in an autopsy series, we found a high prevalence of microcarcinomas (MCs) (21/443 = 4.74%). We found no iodine intake-, gender-, or age-dependent differences in the prevalence of MCs. The results suggest a different and benign behavior of MCs compared to clinical cancer. The role of cyclin D1 overexpression in the pathogenesis of thyroid tumors is not known clearly; however, overexpression of this protein was reported in well-differentiated papillary cancers and in incidentally found metastasizing MCs. To date, cyclin D1 expression has not been investigated in autopsy-derived thyroid MCs. Eight MCs were available for immunostaining and comparison with 15 clinically detected papillary thyroid cancers. Fourteen out of 15 clinical carcinomas expressed cyclin D1 (93.3%), while in the MCs this ratio was 1 out of 8 (12.5%) (p = 0.0001). The only cyclin D1-positive MC was multifocal (both lobes of the gland were affected). We concluded that the benign behavior of most autopsy-derived MCs may be associated with the lack of cyclin D1 overexpression.

Epidemiology of thyroid microcarcinoma found in autopsy series conducted in areas of different iodine intake.

The prevalence of thyroid microcarcinomas found at autopsies is 100-1000 times higher than in clinical cancer. The epidemiological and histological characteristics of thyroid microcarcinomas in consecutive series of autopsies performed in two areas of different iodine intake were investigated. Iodine deficient (ID) area: n = 222 (M = 109, F = 113), median age: 74-76 years, median iodine excretion (MIE) of nursing home residents from this area: 70 microg/g creatinine. Iodine sufficient (IS) area: n = 221 (M = 132, F = 89), median age: 68 years, MIE: 500 microg/g creatinine. When compared to the IS area, the results obtained in the ID area showed a higher thyroid weight (mean 27.75 g +/- 18.43 g vs. 16.5 g +/- 9.6 g, p < 0.0001) and a larger number of goitrous glands (50/222 vs. 5/221, p < 0.0001). Altogether 21 microcarcinomas were found (4.74%) with no iodine intake- or gender-related difference: ID n = 11 (4.95%), M/F = 8/3; IS n = 10 (4.52%), M/F = 6/4. Microcarcinomas seemed to be more prevalent in the 40-59-year age group. All microcarcinomas were of the papillary type. In conclusion, compared to clinical cancer, thyroid microcarcinomas are characterized by a two-scale higher prevalence, are not related to iodine intake, gender or nodularity, are most exclusively of the papillary type.

[Correlations between the hypothalamo-pituitary-adrenal axis and the metabolic syndrome]. / A hypothalamus-hypophysis-mellékvese tengely es a metabolikus szindróma kapcsolata.

The metabolic syndrome has several similarities with Cushing's syndrome (impaired glucose tolerance, hypertension, dyslipidemia, central obesity) suggesting that abnormalities in the regulation of the hypothalamic-pituitary-adrenal axis may have a link with the metabolic syndrome. Several studies suggested an association between the clinical signs of the metabolic syndrome and the increased hypothalamic-pituitary-adrenal axis activity based on increased cortisol concentration at 09.00 a.m. and increased cortisol response to corticotropin. According to the Barker hypothesis the fetal malnutrition could determine adult cardiovascular diseases (coronary heart disease, hypertension), some endocrine and metabolic disorders (obesity, type 2 diabetes and hyperlipidemia). The suggested mechanism of the phenomenon is that the suboptimal fetal nutrition results in glucocorticoid overproduction. The 11beta-hydroxysteroid dehydrogenase (converts biological inactive cortisone to cortisol and vice versa) is an important enzyme in cortisol metabolism. The increased expression of 11beta-hydroxysteroid dehydrogenase type 1 in fat tissue could lead to central obesity and impaired glucose tolerance. The hypothesis that increased corticotropin-releasing hormone production drives the overactive hypothalamo-pituitary-adrenal axis was not proven. Further investigations are needed to identify additional pathogenetic factors and to find new therapeutic possibilities.

Effect of growth hormone replacement therapy on pituitary hormone secretion and hormone replacement therapies in GHD adults.

OBJECTIVE: We tested the impact of commencement of GH replacement therapy in GH-deficient (GHD) adults on the circulating levels of other anterior pituitary and peripheral hormones and the need for re-evaluation of other hormone replacement therapies, especially the need for dose changes. METHODS: 22 GHD patients were investigated in a double-blind randomized study and 90 GHD patients in an open study at baseline and after 6 and 12 months of GH replacement therapy. RESULTS: In the placebo-controlled trial, the FT(3) levels increased after 6 months in the GH-treated group, and in the open study the FT(3) levels tended to increase. Other hormone concentrations did not change in either part of the study. Four patients required an increase in thyroxine dose, while 2 patients needed dose reduction. One originally euthyroid patient required thyroxine replacement. Two patients with originally conserved pituitary-adrenal function developed ACTH insufficiency. The hydrocortisone dose was increased in 1 and decreased in 1 of the 66 patients with secondary hypocortisolism. None of the females required any adjustment of sex hormone replacement therapy. Two of 37 males needed dose increase of testosterone, while 1 needed dose reduction. CONCLUSION: GH replacement therapy required dose adjustments regarding other hormone replacement therapies in 12.2% (n = 11), while initiation of new hormone replacement was performed in 3.3% (n = 3) of the 90 patients during the 1-year follow-up. Monitoring of pituitary hormone axes is advisable after commencement of GH replacement therapy, since changes of hormone replacement therapy was observed in a small but clinically significant number of patients.

Thyrotropin secretion during oral glucose tolerance test in acromegalic patients and control subjects.

It has been suggested that acute hyperglycemia stimulates somatostatin release from the hypothalamus, thus causing inhibition of growth hormone and thyrotropin secretion. Abnormal growth hormone secretory pattern to glucose load is characteristic of acromegaly, and it might reflect alterations in somatostatin release. We evaluated the sensitivity of serum thyrotropin response to presumed somatostatin inhibition during oral glucose tolerance test in 29 patients with active acromegaly, in 13 patients with inactive disease, and in 19 control persons suspected of impaired glucose tolerance. Both the acromegalic patients and the control subjects were euthyroid. Serum insulin, growth hormone, thyrotropin, free triiodthyronine, free thyroxine, and glucose were collected before and 30, 60, 90, and 120 min after the ingestion of 75 g glucose. While the free triiodthyronine and free thyroxine values did not change during the glucose test, the thyrotropin levels progressively and significantly declined in all groups. The basal to nadir thyrotropin ratio was higher in active acromegaly than in inactive disease and in control subjects (p < 0.01), suggesting that the glucose load inhibited thyrotropin stronger in active acromegalic patients. These data suggest that there is a possible strong somatostatin response to glucose load in acromegalic patients, which inhibits thyrotropin secretion. These data do not support the concept of decreased somatostatin drive in acromegaly.

Physiological and pathological angiogenesis in the endocrine system.

Formation of new blood vessels occurs in many physiological states (during development of the embryo, cycling changes of the female reproductive tract), as well as in pathological processes (such as diabetic retinopathy and wound healing). Angiogenesis has been shown to be related to tumor formation, prognosis, and response to treatment in many tumor types. Intratumoral microvessels can be related to tumor behavior or hormone secretion in different endocrine tumors. For example, invasive prolactinomas are more vascular than noninvasive adenomas; a surgical approach is more successful in macroprolactinomas with lower microvessel density. A higher number of microvessels have been found in papillary thyroid carcinomas during recurrences. A correlation between microvessel count and prognosis in papillary and medullary thyroid carcinomas has been suggested. Several stimulating and inhibiting factors involved in the regulation of angiogenesis have been identified. Among them, vascular endothelial growth factor (VEGF) has been shown to be critically involved in angiogenesis and also in the neovascularization of solid tumors. Dopamine agonists (already in clinical use for prolactinomas) have potent inhibitory actions on VEGF signaling, and thus may be a new tool in antiangiogenic therapy. Secretion of VEGF in the great majority of human pituitary adenomas is inhibited by dexamethasone. This suggests that glucocorticoids can be considered in the treatment of certain pituitary tumors. The cyclic nature of angiogenesis in the female reproductive tract indicates that stimulation or inhibition of paracrine angiogenic factors may lead to new approaches for being able to influence reproductive endocrine disorders. Experimental and clinical aspects of interactions between angiogenic factors and tumor growth of the endocrine system are also discussed.

Dexamethasone and adrenocorticotropin suppress prolactin secretion in humans.

It has been demonstrated that the regulatory pathways mediating basal and/or stimulus-induced prolactin (PRL) release in mammals are highly sensitive to adrenal corticoid inhibitory influence. We have investigated the effect of four different doses of dexamethasone (DEX) and the effect of adrenocorticotropin on PRL secretion in 197 patients (169 female, 28 male; age: 18-66 yr) with suspected hypercortisolemia--but only those with a normal glucocorticoid suppression test were involved in the study--and in 66 female patients (age: 18-39 yr) with suspected adrenocorticotropin-dependent hyperandrogenism. Overnight (1 mg), low-dose (0.5 mg every 6 h for 2 d), high-dose (2 mg every 6 h for 2 d), and long-lasting administration of DEX (0.5 mg every 6 h for 5 d) resulted in a significant decrease in PRL levels compared to the baseline. Similarly, a reduction in PRL levels could be detected following injection of adrenocorticotropin (250 microg). In hyperprolactinemic patients, the DEX-induced increase in PRL (APRL, expressed in percentage of baseline) was significantly larger compared with normoprolactinemic subjects in all groups except those who received high-dose DEX) or adrenocorticotropin. These data clearly indicate that the secretory function of PRL cells in humans is sensitive to changes in the activity of the hypothalamo-pituitary-adrenal axis in a dose-dependent manner.

[Novel pharmacologic therapies in acromegaly]. / Uj gyógyszeres terápiás lehetóségek az acromegalia kezelésére.

The primary aim of therapy should be to remove symptoms, reduce tumor bulk, prevent relapse, and improve long-term outcome. Surgery, radiotherapy and medical therapies are used to achieve these aims. Post-treatment mean "safe" serum growth hormone values of < 2.5 ng/ml should be the therapeutic goal. Transsphenoidal surgery remains the first line treatment for acromegaly. Patients with microadenoma can expect 85%, while those with macroadenoma 50% chance to achieve safe serum growth hormone levels. Less than 20% of acromegalics respond to treatment with bromocriptine, while quinagolide and cabergoline may show better clinical response; the success rate is higher for tumors secreting both growth hormone and prolactin. Dopamine agonists may be considered either in combination with somatostatin-analogues or as monotherapy in selected patients, and in those with co-secretion of prolactin. Octreotide (Sandostatin, Novartis) is a synthetic somatostatin-analogue, which is administered subcutaneously in doses between 100 and 250 micrograms 3 times daily. Long-acting octreotide (Sandostatin LAR, Novartis) contains octreotide incorporated into microspheres of biodegradable polymer. To effectively lower serum growth hormone levels, monthly injections of 10-30 mg of long-acting octreotide are needed, serum growth hormone falls to 2.5 ng/ml in 70% of cases, and serum insulin-like growth factor I normalizes in 67%. Slow release lanreotide (Somatuline SR, Ipsen) is an alternative depot long-acting somatostatin-analogue, which is administered in a dose of 30 mg intramuscularly every 14, 10 or 7 days. Both compounds are equally, if not more, effective than subcutaneous octreotide, and significantly improve patient compliance. Pegvisomant (Sensus Drug Development Corporation) is a genetically engineered growth hormone receptor antagonist, which inhibits growth hormone action. When given subcutaneously in a dose of 20 mg/day, serum insulin-like growth factor I levels return to normal in 90% of patients. Theoretical concerns of tumor expansion have not been a problem to date, but long term studies are needed. Primary medical--somatostatin-analogue--therapy is recommended if surgery fails, if the patient refuses or unsuited for surgery and it may be also considered in patients with macroadenoma with extra--but not suprasellar extension, since the surgical "cure" rates of these tumors are low.