Lenvatinib in Advanced Radioiodine-refractory Thyroid Cancer: A Snapshot of Real-life Clinical Practice

BACKGROUND

We retrospectively analyzed the efficacy and safety of lenvatinib in 12 patients with advanced radioiodine-refractory thyroid cancer in the setting of daily clinical practice.

PATIENTS AND METHODS

The starting daily dose of lenvatinib was 24 mg, tapered in the case of adverse events. Disease status was periodically evaluated by a single radiologist and safety assessment was regularly performed.

RESULTS

After a median follow-up of 13.3 months, 6- and 12-month progression-free survival rates were 63.6% and 54.6%, respectively. Overall survival at 6 and 12 months was 83.3% and 75.0%. Partial response was observed in five patients, while two showed stable disease as their best response. Conversely, progressive disease at first radiological assessment was detected in four patients. All patients experienced at least one adverse event, including systemic and gastrointestinal toxicity, high blood pressure and hand-foot syndrome. In order to manage toxicity, transient drug interruption and dose reduction were required in 10 and 9 cases, respectively.

CONCLUSION

Our data confirm lenvatinib efficacy in patients with advanced thyroid cancer, despite an important toxic profile.

Tyrosine kinase inhibitors rechallenge in solid tumors: a review of literature and a case description with lenvatinib in thyroid cancer

INTRODUCTION

In the last decade tyrosine kinase inhibitors (TKIs) have been employed for a wide range of hematological and solid tumors and today they represent a valid therapeutic option for different neoplasms. Among them, both sorafenib and lenvatinib were approved for the treatment of radioactive iodine (RAI) refractory differentiated thyroid carcinoma (DTC). Unfortunately, in some cases the efficacy of TKIs is limited by the onset of drug resistance after the initial response. Areas covered: We report the case of a patient with a RAI refractory advanced DTC, treated with lenvatinib after surgery, multiple RAI administrations, traditional chemotherapy, and sorafenib. During treatment with lenvatinib, a noticeable response was detected by sequential computed tomography scans but, after 27 months, tumor progression became evident and led to lenvatinib interruption. In absence of any active treatment, a further disease progression was documented, and lenvatinib was re-administered obtaining a new objective response. Starting from this case report, we review available reports about the rechallenge with TKIs in solid tumors, discussing the possible mechanisms underlying the efficacy of this approach. Expert commentary: Rechallenge with TKIs in solid tumors could be a therapeutic option in subjects with advanced and metastatic DTC who experience a progressive disease after initial response to lenvatinib.

The acute effect of a mineralocorticoid receptor agonist on corticotrope secretion in Addison's disease

PURPOSE

Mineralocorticoid receptors (MR) in the hippocampus display an important role in the control of hypothalamic-pituitary-adrenal (HPA) axis, mediating the ''proactive'' feedback of glucocorticoids (GC). Fludrocortisone (FC), a potent MR agonist, has been shown to decrease HPA activity through a hippocampal mechanism. Since it has been demonstrated that FC shows a significant inhibition of the HPA axis response to hCRH stimulus in normal subjects, also at doses usually administered as replacement therapy in patients with Addison's disease, an FC effect at MRs in human pituitary or a GR-pituitary agonism stronger than believed until now has been postulated.

METHODS

Ten patients affected by autoimmune Addison's disease received: (1) placebo p.o. + placebo i.v., (2) hydrocortisone (H) 10 mg p.o. + placebo i.v., (3) FC 0.1 mg p.o. + placebo i.v., (4) FC 0.1 mg and H 10 mg p.o. + placebo i.v. to verify a possible GR FC-mediated effect that might display a repercussion on the GC-replacement therapy.

RESULTS

H reduced ACTH (p < 0.01) and increased cortisol levels (p < 0.01) with respect to the placebo session, while FC did not affect either ACTH or cortisol levels compared to placebo, and higher ACTH and lower cortisol levels (p < 0.03 and p < 0.01) were observed compared with the H session; furthermore the co-administration of FC + H showed ACTH and cortisol profiles similar to that observed during H alone.

CONCLUSIONS

Our study showed a lack of FC effect on corticotrope secretion in Addison's disease, thus making unlikely the hypothesis of its GR pituitary agonism and the risk of glucocorticoid excess in primary adrenal insufficiency.

Improvement of anthropometric and metabolic parameters, and quality of life following treatment with dual-release hydrocortisone in patients with Addison's disease

In patients with Addison's disease (AD), a dual-release preparation of hydrocortisone (Plenadren, PLEN) has been demonstrated to maintain cortisol levels in a more physiological range than conventional glucocorticoid therapy, and to exert positive effects. This study aimed to assess variations of anthropometric, metabolic, and hormonal parameters in patients with AD after switching from conventional hydrocortisone (HC) treatment to PLEN. In nineteen AD patients (15 F and 4 M, age 27-65 years) treated with HC 20 mg/day thrice daily, body weight, BMI, waist circumference, fasting glucose, HbA1c, serum lipids, plasma renin activity, electrolytes, and blood pressure were evaluated at baseline, and 1, 3, 6, and 12 months after switching from HC to PLEN. At baseline, and after 1 and 12 months of PLEN, blood ACTH and cortisol (at 0800 h at fasting, and 30, 60, 90, 120, and 240 min after drug ingestion), and health-related quality of life (HRQoL), using 30-AddiQoL questionnaire, were evaluated. During PLEN, waist and serum lipid progressively decreased. After 12 months of PLEN, a significant difference was observed in waist circumference (P = 0.007), HbA1c (P = 0.002), total and LDL-cholesterol levels (P < 0.05). ACTH levels at 240 min and the area under the curve (AUC) were lower (P < 0.05) during PLEN than HC, while cortisol peaks and AUC were similar. 30-AddiQoL total score also improved (P = 0.04) during PLEN. In AD patients, PLEN reduces central adiposity, and improves glucose and metabolism parameters and HRQoL.

Cushing's syndrome is associated with sleep alterations detected by wrist actigraphy

BACKGROUND

The association between the hypothalamic-pituitary-adrenal (HPA) axis and sleep is well described. It is also known that HPA axis disturbances have an effect on sleep. In fact, patients affected by Cushing's syndrome (CS) often complain about poor sleep quality. Our aim was to evaluate objective sleep quality and duration in patients with Cushing's syndrome in active phase, using wrist actigraphy.

PATIENTS AND METHODS

In 12 patients with active CS without ongoing specific therapy (11 F, 1 M; age 40.0 ± 10.9 years; BMI 28.4 ± 6.7 kg/m(2)) and 12 healthy control subjects (HS) (11 F, 1 M; age 44.0 ± 11.0 years; BMI 23.9 ± 4.2 kg/m(2)) an actigraphic evaluation was performed on 3 consecutive days under free living conditions. Objective measurement of sleep duration and quality was estimated by an actiwatch, which is a wristwatch-like device used to detect motor activity.

RESULTS

In CS patients, wrist actigraphy showed higher fragmented sleep (fragmentation index CS 16.2 ± 4.2, HS 13.0 ± 3.6; p = 0.034) and increased nocturnal motor activity (total activity score CS 8318 ± 4308, HS 4971 ± 2372; p = 0.020; mean activity score CS 8.7 ± 4.2, HS 5.4 ± 2.2; p = 0.030; mean score in active time CS 104.8 ± 39.2, HS 74.8 ± 23.1; p = 0.030). On the contrary, actual sleep time resulted similar in CS and HS. No correlation was found between sleep alterations and urinary free cortisol in patients.

CONCLUSIONS

The impaired actigraphic parameters described in our study suggest that hypercortisolism is associated with sleep alterations, which could contribute to the worsening of life quality and metabolic comorbidities associated with CS. These results have to be confirmed in a larger cohort of patients, using more accurate instruments for sleep assessment.

Retrospective observational analysis of non-irradiated non-functioning pituitary adenomas

PURPOSE

The management of choice of non-functioning pituitary adenomas (NFPAs) remains debulking surgery when symptomatic. However, patient series systematically reporting the NFPAs outcome that were not treated either surgically, medically or with radiotherapy during long follow-up thereby giving an indication of their natural history are limited. Aim of the present study was to evaluate the natural course of presumed NFPAs, the outcome of confirmed NFPAs during a long follow-up period.

METHODS

Between 1993 and 2013, 84 patients with presumed NFPA were studied retrospectively. Patients were enrolled based on the following criteria: imaging suggestive of pituitary adenoma, absence of any biochemical/clinical evidence of hormonal excess, exclusion of prolactinomas and at least one sequential imaging during the follow-up. Repeated assessment of the pituitary function, visual fields and imaging was performed at regular intervals. The follow-up duration was evaluated from the first and last imaging dates.

RESULTS

In group F (follow-up without surgery, 33 patients), the macroadenomas showed a 15% probability of tumor growth and reduction. Similar tumor size alterations were observed also for the microadenomas. In group S (surgery, 51 patients), both residual tumors (>1 and <1 cm) following initial surgical resection remain mainly stable until the last imaging.

CONCLUSIONS

Based on the given lack of approved medical treatment and the possible risks of surgical intervention in presence of significant comorbidities, our study proposes a conservative approach with a careful follow-up in patients with NFPAs without visual or neurological abnormalities.

Insulin and GH-IGF-I axis: endocrine pacer or endocrine disruptor?

Growth hormone/insulin-like growth factor (IGF) axis may play a role in maintaining glucose homeostasis in synergism with insulin. IGF-1 can directly stimulate glucose transport into the muscle through either IGF-1 or insulin/IGF-1 hybrid receptors. In severely decompensated diabetes including diabetic ketoacidosis, plasma levels of IGF-1 are low and insulin delivery into the portal system is required to normalize IGF-1 synthesis and bioavailability. Normalization of serum IGF-1 correlated with the improvement of glucose homeostasis during insulin therapy providing evidence for the use of IGF-1 as biomarker of metabolic control in diabetes. Taking apart the inherent mitogenic discussion, diabetes treatment using insulins with high affinity for the IGF-1 receptor may act as an endocrine pacer exerting a cardioprotective effect by restoring the right level of IGF-1 in bloodstream and target tissues, whereas insulins with low affinity for the IGF-1 receptor may lack this positive effect. An excessive and indirect stimulation of IGF-1 receptor due to sustained and chronic hyperinsulinemia over the therapeutic level required to overtake acute/chronic insulin resistance may act as endocrine disruptor as it may possibly increase the cardiovascular risk in the short and medium term and mitogenic/proliferative action in the long term. In conclusion, normal IGF-1 may be hypothesized to be a good marker of appropriate insulin treatment of the subject with diabetes and may integrate and make more robust the message coming from HbA1c in terms of prediction of cardiovascular risk.

Enhanced oxidative stress and platelet activation in patients with Cushing's syndrome

OBJECTIVE

Cushing Syndrome (CS) is implicated by increased cardiovascular risk (CVR) leading to increased morbidity and mortality. Oxidative stress (OS) and platelet activation (PA) are associated with increased CVR. However, scarce data of OS in CS exist. Our objective was to determine the oxidant-antioxidant balance in CS.

DESIGN

Fourteen patients with CS at diagnosis and fourteen healthy subjects (NS) were evaluated OS by measuring plasma 15-F2t -Isoprostane (15-F2t -IsoP), PA by thromboxaneB2 levels (TXB2 ), and antioxidant reserve measuring total antioxidant capacity (TAC) and serum vitamin E.

RESULTS

15-F2t -IsoP and TXB2 levels were significantly higher (P < 0·01) in CS, while vitamin E levels were higher in NS (P < 0·03). 15-F2t -IsoP levels were significantly higher (P < 0·01) in complicated vs not-complicated CS and NS and significantly higher (P < 0·03) in CS not-complicated vs NS. TXB2 levels were significantly reduced (P < 0·03) in NS vs complicated and not-complicated CS. A negative correlation between Vitamin E and UFC was observed in CS (P < 0·05 r = -0·497). TXB2 correlated with glucose, HbA1c and T-score (P < 0·05 r = 0·512, P < 0·03 r = 0·527 and P < 0·01 r = 0·783, respectively) and HDL (P < 0·01 r = -0·651). 15-F2t -IsoP correlated with triglicerides, HbA1c and diastolic pressure (P < 0·01 r = 0·650, P < 0·03 r = 0·571 and P < 0·05 r = 0·498, respectively) and HDL (P < 0·03 r = -0·594).

CONCLUSIONS

This study emphasizes the major role of OS in CS. As our findings demonstrated that enhanced OS and PA take place in this rare metabolic disorder which is associated with increased CVR, it could be suggested that these biochemical alterations can further contribute in the pathogenesis of atherosclerosis, increased CVR and mortality in CS.

Dual-release Hydrocortisone in Addison's Disease - A Review of the Literature

In patients with adrenal insufficiency, glucocorticoids (GCs) are insufficiently secreted and GC replacement is essential for health and, indeed, life. Despite GC-replacement therapy, patients with adrenal insufficiency have a greater cardiovascular risk than the general population, and suffer from impaired health-related quality of life. Although the aim of the replacement GC therapy is to reproduce as much as possible the physiological pattern of cortisol secretion by the normal adrenal gland, the pharmacokinetics of available oral immediate-release hydrocortisone or cortisone make it impossible to fully mimic the cortisol rhythm. Therefore, there is an unmet clinical need for the development of novel pharmaceutical preparations of hydrocortisone, in order to guarantee a more physiological serum cortisol concentration time-profile, and to improve the long-term outcome in patients under GC substitution therapy.

The acute effect of fludrocortisone on basal and hCRH-stimulated hypothalamic--pituitary--adrenal (HPA) axis in humans

Mineralocorticoid receptors (MR) in the hippocampus display an important role in the control of hypothalamic-pituitary-adrenal (HPA)-axis, mediating the "proactive"-feedback of glucocorticoids. Fludrocortisone (FC), a potent MR agonist, has been shown to decrease HPA activity through a mechanism placed at hippocampal level. In order to clarify the effects of MR agonism on HPA function in humans, we studied the effects of FC, in a dose-related manner, on both basal and CRH-stimulated HPA axis during the quiescent phase. 8 young women were studied. ACTH, cortisol and aldosterone levels were evaluated every 15', from 1600 to 2000 hours, in randomized sessions: (1) placebo p.o. + placebo i.v., (2) 0.3 mg FC p.o. + placebo, (3) 0.1 mg FC. + placebo, (4) 0.075 mg FC + placebo, (5) 0.05 mg FC + placebo, (6) placebo + hCRH (2.0 μg/kg iv-bolus), (7) 0.3 mg FC + hCRH, (8) 0.1 mg FC + hCRH, (9) 0.075 mg FC + hCRH, (10) 0.05 mg FC + hCRH. FC induced a dose-related trend toward a further decrease of the ACTH and cortisol levels, while it showed a significant and dose-dependent inhibition of the hormonal response to hCRH (p < 0.05 for the doses of 0.3, 0.1 and 0.075 mg). Conversely, 0.05 mg FC did not modify the CRH-stimulatory effect on both ACTH and cortisol secretion. Aldosterone levels were not modified by FC administration. Fludrocortisone inhibits corticotrope and adrenal response to hCRH in humans, in a dose-dependent manner. The 0.075 mg FC seems the lowest active while 0.05 mg the first neutral dose on HPA activity. These data suggest a possible hypophysial MR-mediated inhibiting effect of FC, although its pituitary glucocorticoid-mediated effect cannot be excluded. The interplay between fludrocortisone and hypophysial glucocorticoid receptors needs to be clarified in order to define better the clinical consequences of the hormonal replacement therapy of patients with primary adrenal insufficiency.

Acute administration of alprazolam, a benzodiazepine activating GABA receptors, inhibits cortisol secretion in patients with subclinical but not overt Cushing's syndrome

The purpose of this study is to verify whether acute pre-treatment with alprazolam (ALP), a benzodiazepine that inhibits HPA secretion in normal subjects, could better characterize patients with subclinical Cushing's syndrome (SCS) than the 1-mg dexamethasone test (DST). In 22 patients with SCS, 10 with overt Cushing's syndrome (CS), 11 with non-functioning adrenal incidentalomas (NF) and 14 normal subjects (NS) we studied the effect of ALP (1 mg, p.o. at 2300 hours) on cortisol levels after 1-mg DST. Cortisol levels (mean ± SEM) after DST were lower (P = 0.012) in SCS (3.9 ± 0.3 μg/dl) than in overt CS (10.4 ± 1.9 μg/dl), while they were higher (P = 0.0005) than in NF (1.1 ± 0.1 μg/dl) and NS (1.5 ± 0.1 μg/dl). After ALP pre-treatment, cortisol levels further decreased (P = 0.004) in SCS (3.0 ± 0.3 μg/dl), but neither in CS (9.3 ± 1.3 μg/dl) nor in NF (1.3 ± 0.1 μg/dl) and in NS (1.3 ± 0.1 μg/dl). In SCS, cortisol levels after ALP + 1-mg DST persisted lower (P = 0.0005) than those in CS, but higher (P = 0.0005) than those in NF and NS. Considering individual cases, ALP pre-treatment reduced cortisol levels < 3 and < 1.8 μg/dl in 50 and 23 % of SCS patients, respectively. ALP amplifies the cortisol inhibition exerted by 1-mg DST in patients with SCS but not in those with CS. The clinical usefulness of ALP to increase the sensitivity of 1-mg DST to identify true autonomous cortisol release in patients with adrenal incidentalomas as well as to predict different clinical outcomes remains to be clarified.

Role of mineralocorticoid receptors on the hypothalamus-pituitary-adrenal axis in humans

This clinical review will summarize the available data regarding the role of mineralocorticoid receptors (MRs) on the hypothalamus-pituitary-adrenal (HPA) axis control in physiological and pathological conditions and in the memory processes involved in the control and appraisal of a stress event. MRs are predominantly expressed in the limbic structures, with the hippocampus being the main localization, although MRs are also found at the hypothalamic level. It is known that hyppocampal MRs control the proactive feedback involved in the maintenance of the basal HPA activity, mainly at the nadir of the circadian rhythm. In physiological conditions, the administration of pharmacological doses of both MR antagonists and agonists is able to interact with the HPA activity, modifying the quiescent phase-nadir of the circadian rhythm, although some data in the literature do not support these observations. Also, in a physiological condition such as aging, an enhanced HPA axis activity is found in the time window, when MRs are predominantly occupied by cortisol circulating levels, possibly reflecting an MR impairment in this period of life. In pathology, major depression has been correlated to MR qualitative-quantitative alterations which could reflect differences on psychological and physiological responses, possibly predicting psychopathologies. Most of the remarks reported in this review seem to indicate, in agreement with animal data, a role played by MRs in the delicate control of the HPA axis in humans and the possible predisposition to the development of pathologies in case of their alterations.

BClI polymorphism of the glucocorticoid receptor gene is associated with increased obesity, impaired glucose metabolism and dyslipidaemia in patients with Addison's disease

OBJECT

Although glucocorticoids are essential for health, several studies have shown that glucocorticoids replacement in Addison's disease might be involved in anthropometric and metabolic impairment, with increased cardiovascular risk, namely if conventional doses are used. As the effects of glucocorticoids are mediated by the glucocorticoid receptor, encoded by NR3C1 gene, different polymorphisms in the NR3C1 gene have been linked to altered glucocorticoid sensitivity in general population as well as in patients with obesity or metabolic syndrome.

DESIGN

We investigated the impact of glucocorticoid receptor gene polymorphisms, including the BclI, N363S and ER22/23EK variants, on anthropometric parameters (BMI and waist circumference), metabolic profile (HOMA, OGTT and serum lipids) and ACTH levels in 50 patients with Addison's disease (34 women and 16 men, age 20-82 year) under glucocorticoids replacement.

RESULTS

Neither N363S nor ER22/23EK variants were significantly associated with anthropometric, metabolic or hormonal parameters, while patients carrying the homozygous BclI polymorphism GG (n = 4) showed higher (P < 0·05) BMI, waist circumference, HOMA and 2-h glucose levels after OGTT, as well as total cholesterol and triglycerides than those with wild-type genotype CC (n = 28) or heterozygous CG (n = 18). The totality of GG patients was connoted by abdominal adiposity, impaired glucose tolerance/diabetes mellitus or dyslipidaemia, while a lower percentage of CC or CG patients showed some anthropometric and metabolic alterations.

CONCLUSION

These results suggest that BclI polymorphism may influence the sensitivity to glucocorticoids in patients with Addison's disease and may contribute, along with other factors, to the increase in central adiposity, impaired glucose metabolism and dyslipidaemia.

Glucose metabolism in patients with subclinical Cushing's syndrome

This clinical review will summarize the available data regarding the effect of either physiological or increased glucocorticoid concentrations on glucose metabolism and insulin-sensitivity, in order to clarify the role, if any, of subclinical Cushing's syndrome (SCS), a status of altered hypothalamic-pituitary-adrenal axis secretion in the absence of the classical signs or symptoms of overt cortisol excess, in patients with adrenal incidentalomas (AI) and diabetes mellitus type 2. Focusing on patients with SCS associated to AI, while there is convincing evidence in the literature that even a mild hyper cortisolemia is associated with alterations of glucose metabolism, evidence is insufficient to conclude that the simple correction of chronic, even mild, hypercortisolism can completely revert metabolic, mainly glycemic alterations. At the same time, considering the variability of the prevalence of Cushing's syndrome in patients with diabetes mellitus type 2 reported in the literature, no agreement does exist whether screening for CS can be useful and recommended in those patients.

Effects of cetrorelix, a GnRH-receptor antagonist, on gonadal axis in women with functional hypothalamic amenorrhea

BACKGROUND

Gonadotropin Releasing Hormone (GnRH) antagonists (GnRHa) suppress gonadotropin and sex-steroid secretion. In normal women, acute GnRHa administration induces inhibitory effect on pituitary-gonadal axis, followed by Luteinizing Hormone (LH) rebound. Functional hypothalamic amenorrhea (HA) is characterised by impaired gonadotropin secretion and hypogonadism secondary to blunted GnRH pulsatility.

METHODS

We studied the effects of a GnRHa, cetrorelix (CTX 3.0 mg), in six women with HA (age 30.7 ± 3.2 years; BMI 21.5 ± 1.7 kg/m(2)) and six control subjects (CS, 28.2 ± 0.6 years; 22.6 ± 0.9 kg/m(2)) on LH, Follicle-Stimulating Hormone (FSH) and oestradiol levels over 4 h (08.00-12.00 am) before, +24 h and +96 h after CTX; LH, FSH, and oestradiol were also evaluated at +6, +8, +12, +48, +72 h after CTX.

RESULTS

CS: CTX reduced (p < 0.05) LH, FSH, and oestradiol (nadir at +12 h, +24 h, and +24 h); LH rebounded at +96 h, FSH and oestradiol recovered at +48 h and +72 h. The 4-h evaluation showed LH and FSH reduction (p < 0.05) at +24 h, with LH rebound at +96 h. HA: CTX reduced (p < 0.05) LH, FSH, and oestradiol, (nadir at +24 h, +48 h, and +48 h, recovery at +48 h, +72 h, and +96 h). The 4-h evaluation showed gonadotropin reduction (p < 0.05) 24 h after CTX, without any rebound effect.

CONCLUSIONS

One single CTX dose still modulates gonadotropin secretion in HA. Its 'paradoxical' stimulatory effect on gonadotropins needs to be verified after prolonged administration.

Metabolic and cardiovascular outcomes in patients with Cushing's syndrome of different aetiologies during active disease and 1 year after remission

OBJECTIVE

Cushing's syndrome is associated with several comorbidities responsible for the increased cardiovascular risk, not only during the active phase but also after disease remission.

DESIGN

In 29 patients with Cushing's syndrome (14 Cushing's diseases and 15 adrenal adenomas), waist circumference, fasting and 2-h glucose after oral glucose tolerance test (OGTT), lipid profile and blood pressure were evaluated during the active disease and 1 year after remission and compared with those in 29 sex-, age- and BMI-matched controls.

RESULTS

During the active disease, waist circumference, 2-h glucose after OGTT, total and LDL cholesterol were higher in patients with Cushing's syndrome than in controls (P < 0·001) but similar in Cushing's disease and adrenal adenomas. The prevalence of impaired glucose tolerance (IGT), diabetes mellitus, dyslipidaemia and hypertension was higher (P < 0·001) in patients with Cushing's syndrome (27%, 24%, 59% and 72%) than in controls (10%, 0%, 21% and 10%), with no significant difference between Cushing's disease and adrenal adenomas. One year following hormonal remission, waist circumference persisted higher than in controls (P < 0·05) in both Cushing's disease and adrenal adenomas. Metabolic and cardiovascular abnormalities were still present in both groups, although with a lower prevalence, as well as with a more marked decrease in adrenal adenomas (P < 0·05 vs active disease for IGT, dyslipidaemia and hypertension).

CONCLUSIONS

These results show that chronic hypercortisolism, independently of its aetiology, contributes to metabolic impairment and increased cardiovascular risk, while these abnormalities mostly persist in patients with previous Cushing's disease after hormonal remission. Pituitary hormonal deficiencies, hormonal replacement treatments and/or incomplete cure from Cushing's disease may account for these findings.

Enhanced oxidative stress and platelet activation combined with reduced antioxidant capacity in obese prepubertal and adolescent girls with full or partial metabolic syndrome

In adults, obesity is a main factor implicated in increased oxidative stress (OS), platelet activation (PA) and impaired antioxidant status (AS), all predisposing factors for cardiovascular disease leading to increased morbidity and mortality. Furthermore, the metabolic syndrome (MetS) is an important cardiovascular risk factor, which progressively develops and may already be present during late childhood or adolescence. However, scarce data exist on oxidative-antioxidant balance and PA in childhood and adolescence in the presence of partial (PMetS) or full MetS. The aim of the study was to evaluate OS, PA, and AS in prepubertal and adolescent obese girls with partial or full MetS. 96 girls with a clinical and metabolic evaluation for obesity and 44 healthy normal-weight sex- and age-matched girls were studied. IDF-adopted criteria were used to define full and partial MetS and the patient population was divided into 4 groups: the first comprised 31 pre-pubertal girls with PMetS (PR-PMetS), the second 37 adolescents with PMetS (AD-PMetS), the third 10 prepubertal girls with full MetS (PR-MetS), and the fourth 18 adolescents with full MetS (AD-MetS). The OS was evaluated by measuring plasma 15-F(2t)-Isoprostane levels (15-F(2t)-IsoP) and protein carbonyls, PA by thromboxane B(2) levels (TXB(2)), and AS by serum vitamin E and plasma total antioxidant capacity (TAC) levels. 15-F(2t)-IsoP, protein carbonyls, and TXB(2) levels were significantly gradually amplified, and vitamin E and TAC reduced, and significantly correlated with obesity from childhood to adolescence and from partial to full MetS. This study demonstrates the loss of the normal homeostatic balance between oxidant-antioxidant state in obese children and adolescents with manifestations of partial and full MetS.

Neuroendocrine effects of citalopram, a selective serotonin re-uptake inhibitor, during lifespan in humans

OBJECTIVE

Serotonergic system contributes to the regulation of hypothalamus-pituitary-adrenal axis. In humans, serotonergic agonists increase PRL, ACTH, and cortisol, while serotonin (5HT) influence on GH is controversial. Central 5HT activity and neuroendocrine function change during lifespan.

DESIGN

To clarify the neuroendocrine response to 5HT across lifespan, we assessed ACTH, cortisol, DHEA, PRL, and GH responses to citalopram (CT) in young adults (YA) (no.=12, 29.2±1.7 yr mean±SEM), middle aged (MA) (no.=12, 54.3±0.9 yr), and elderly (ES) (no.=12, 69.3±0.9 yr) males. All the subjects received placebo (saline iv over 120 min) or CT (20 mg iv over 120 min). Blood samples were taken every 15 min up to 240 min.

RESULTS

During placebo, ACTH, cortisol, GH, and PRL were similar in all groups while DHEA showed an age-dependent reduction from middle age (p<0.001). During CT, ACTH, and cortisol were higher than during placebo in YA (p<0.05) and even more in MA (p<0.01 vs placebo, p<0.05 vs YA); in ES, the increase of both ACTH and cortisol (p<0.05 vs placebo) was lower than in MA (p<0.05) and higher than in YA (p<0.05 for cortisol only). No changes were observed for DHEA, GH, and PRL in any group.

CONCLUSIONS

Corticotrope response to CT is age-dependent in normal men, being amplified starting from middle age, suggesting precocious changes in the serotonergic neuroendocrine control during lifespan. CT is a useful tool to evaluate the age-dependent serotonergic function in humans.

Effect of acute and prolonged mineralocorticoid receptor blockade on spontaneous and stimulated hypothalamic-pituitary-adrenal axis in humans

CONTEXT

Mineralocorticoid receptors (MRs) in the hippocampus display an important role in the control of the hypothalamic-pituitary-adrenal (HPA) axis, mediating the proactive feedback of glucocorticoids, which maintains the basal HPA activity. The systemic administration of MR antagonists enhances spontaneous and CRH-stimulated ACTH, cortisol, and DHEA secretion, while the effects of chronic treatment with MR antagonists are scanty. Our study was performed in order to clarify this point.

DESIGN

ACTH, cortisol, and DHEA levels were studied during the infusion of placebo, canrenoate, a MR antagonist (CAN, 200 mg i.v. bolus at 1600 h followed by 200 mg infused over 4 h), and human CRH (hCRH; 2.0 microg/kg i.v. bolus at 1800 h) before and during the last week of 28-day treatment with CAN (200 mg/day p.o.) in eight young women.

RESULTS

Pre-treatment sessions: CAN and hCRH administration increased ACTH, cortisol, and DHEA levels versus placebo (P<0.05). Post-treatment sessions: during placebo infusion, cortisol and DHEA were significantly amplified versus pre-treatment session (P<0.05), while ACTH levels were not modified; CAN infusion, differently from pre-treatment session, was not able to significantly increase ACTH, cortisol, and DHEA levels; ACTH, cortisol, and DHEA responses to hCRH were amplified with respect to pre-treatment session, although statistical significance was obtained for cortisol and DHEA only.

CONCLUSIONS

MR blockade by acute CAN administration significantly enhances the HPA activity in the afternoon, during the quiescent phase of the circadian rhythm. At the same period, prolonged treatment with CAN amplifies both spontaneous and CRH-stimulated activities of the HPA axis, while it blunts the HPA responsiveness to a further MR-mediated stimulation.

Long-term morphological, hormonal, and clinical follow-up in a single unit on 118 patients with adrenal incidentalomas

OBJECTIVE

To evaluate long-term morphological, functional, and clinical outcome in adrenal incidentalomas.

DESIGN AND METHODS

A total of 118 patients (77 F and 47 M; age 62.3+/-1.0 years) with adrenal incidentalomas were evaluated at baseline and followed-up for median 3 years (range 1-10 years) by clinical, biochemical, hormonal, and morphological evaluation. Among them, six patients with diagnosis of subclinical Cushing's syndrome (SCS) underwent surgery.

RESULTS

At entry, 86% (n=102) of tumors were nonfunctioning (NF) and 14% (n=16) showed SCS. Comparing NF with SCS patients, a significantly higher percentage of dyslipidemia was found in the group of SCS patients (50 vs 23%, P=0.033). During follow-up, adrenal function remained normal in all NF patients, none of them developed subclinical or overt endocrine disease. The cumulative risk of mass enlargement was globally low (25%), but progressive up to 8 years. SCS was confirmed in all patients, and none of them shifted to overt Cushing's syndrome. The cumulative risk of developing metabolic-cardiovascular abnormalities was globally low (22%), but progressive up to 8 years and new diseases were recorded in the group of NF patients only (three patients with dyslipidemia, four with impaired fasting glucose/impaired glucose tolerance, and three with diabetes mellitus). SCS patients who underwent surgery did not show any significant clinical improvement.

CONCLUSIONS

The risk of mass enlargement, hormonal, and metabolic impairment over time is globally low. Conservative management seems to be appropriate, but further prospective studies are needed to establish the long-term outcome of such patients, especially for metabolic status, cardiovascular risk profile and their relationship with endocrine function.

Metabolic and cardiovascular profile in patients with Addison's disease under conventional glucocorticoid replacement

OBJECTIVE

Although two studies have shown that Addison's disease (AD) is still a potentially lethal condition for cardiovascular, malignant, and infectious diseases, a recent retrospective study showed a normal overall mortality rate. Differently from secondary hypoadrenalism, scanty data exist on the role of conventional glucocorticoid replacement on metabolic and cardiovascular outcome in AD.

SUBJECTS AND METHODS

In 38 AD under conventional glucocorticoid replacement (hydrocortisone 30 mg/day or cortisone 37.5 mg/day) ACTH, plasma renin activity (PRA), DHEAS, fasting glucose and insulin, 2-h glucose after oral glucose tolerance test, serum lipids, 24-h blood pressure and intima-media thickness (IMT) were evaluated and compared with 38 age-, sex- and body mass index (BMI)-matched controls (CS).

RESULTS

AD had ACTH and PRA higher and DHEAS lower (p<0.0005) than CS. Mean waist was higher (p<0.05) in AD than in CS. Although no differences were found for mean gluco-lipids levels, a higher percentage of AD compared to CS were IGT (8 vs 0%), hypercholesterolemic (18 vs 8%), and hypertriglyceridemic (18 vs 8%); none of the AD and CS showed either HDL<40 mg/dl or LDL>190 mg/dl. At the multiple regression analysis, in both AD and CS, BMI was the best predictor of 2-h glucose and age of total and LDL cholesterol; in AD, no significant correlation was found between the above mentioned metabolic parameters and either hormone levels or disease duration. In both AD and CS 24-h blood pressure and IMT were normal.

CONCLUSIONS

Our study shows a higher prevalence of central adiposity, impaired glucose tolerance and dyslipidemia in AD patients.

Hypothalamus-pituitary-adrenal axis evaluation in patients with hypothalamo-pituitary disorders: comparison of different provocative tests

BACKGROUND

The insulin tolerance test (ITT) is the gold standard test to evaluate hypothalamic-pituitary-adrenal (HPA) axis in suspected ACTH insufficiency. When contraindicated, alternative tests have been proposed such as metyrapone and ACTH stimulation test. 250 microg ACTH is a supramaximal dose and unreliable in this setting. The diagnostic reliability of 1.0 microg ACTH test is controversial and very low doses have been proposed.

DESIGN

In 31 patients with hypothalamo-pituitary disorders and normal basal cortisol, we compared the diagnostic sensitivity, specificity and accuracy of metyrapone [metyrapone test (MET) 30 mg/kg p.o.], high (HDT, 250 microg i.v.), low (LDT, 1.0 microg i.v.) and very-low (VLDT, 0.06 microg i.v.) dose ACTH tests. Receiver operator curve (ROC) analysis was applied with ITT as reference test.

RESULTS

MET approached the best pairs of values for highest sensitivity (71.4% and 64.3%) and highest specificity (100% and 82.4%) using ACTH and 11-deoxycortisol (11-DOC) cut-off of 17.3 pmol/l and 144.3 nmol/l. Either HDT or LDT sensitivity approached 71.4% with a specificity of 82.4% or 73.3% with a specificity of 80% for cortisol cut-off of 582.1 or 477.3 nmol/l. VLDT approached the highest sensitivity (57.1%) and highest specificity (88.2%) for a cortisol cut-off of 364.2 nmol/l.

CONCLUSION

Neither MET nor ACTH test can be considered completely reliable for the diagnosis of secondary hypoadrenalism, when compared with ITT that remains the best test. Either MET or ACTH stimulation test, at both high and low dose, show an overall similar reliability, provided that appropriated cut-off values were considered; testing with very low ACTH doses seems to be misleading.

Neuroendocrine effects of citalopram infusion in anorexia nervosa

Because of the role of serotonin (5HT) in regulating food intake and mood, several studies have focused their attention on the assessment of serotonergic activity in eating disorders, and in particular in anorexia nervosa, but the results have been inconsistent. Citalopram, a highly selective 5HT reuptake inhibitor, has been recently reported as a neuroendocrine probe to assess the serotonergic function in physiological and pathological conditions. We evaluated the adrenocorticotropic hormone (ACTH), cortisol, prolactin (PRL) and growth hormone (GH) secretion during placebo or citalopram IV infusion (20 mg over 120 min), in six women with anorexia nervosa restricter type, and in six healthy women, in order to test the hypothesis that this neurotransmitter system is abnormal in this group of patients. ACTH and PRL secretion was higher during citalopram infusion compared to placebo (p<0.05) in both groups, while cortisol secretion was higher during citalopram infusion only in healthy controls (p<0.05), but not in anorexic patients. GH levels were unaffected by citalopram in both groups. These results demonstrate that serotonergic activation by citalopram affects corticotroph and lactotroph but not somatotroph secretion in anorexic as well as in normal subjects. Our preliminary findings do not support the existence of remarkable alterations in the serotonergic control of anterior pituitary function in anorexia nervosa, while there seems to be an impairment of the adrenal function in this group of patients.

Corticotrope hypersecretion coupled with cortisol hypo-responsiveness to stimuli is present in patients with autoimmune endocrine diseases: evidence for subclinical primary hypoadrenalism?

OBJECTIVE

In autoimmune polyglandular syndrome types 1, 2, and 4 primary adrenal insufficiency is present, but its diagnosis is often late. We investigated the function of the hypothalamic-pituitary-adrenal axis in a group of patients with autoimmune diseases (AP) without any symptoms and signs of hypoadrenalism.

DESIGN

In 10 AP and 12 normal subjects (NS), we studied cortisol (F), aldosterone (A), and DHEA responses to 0.06 microg adrenocorticotropin (ACTH) (1-24) followed by 250 microg, ACTH and F responses to human corticotropin-releasing hormone (hCRH; 100 microg) and insulin tolerance test (ITT) (0.1 UI/kg).

RESULTS

Basal F, A, DHEA, as well as urinary free cortisol and plasma renin activity levels in AP and NS were similar, whereas ACTH levels in AP were higher (P<0.05) than in NS. NS showed F, A, and DHEA response to both consecutive ACTH doses. In AP, the F, A, and DHEA responses to 250 microg ACTH were similar to those in NS, whereas the 0.06 microg ACTH dose did not elicit any significant response. The ACTH responses to hCRH and ITT in AP were higher (P<0.05) than in NS. The F response to hCRH in AP was lower (P<0.05) than in NS, whereas the F response to ITT in AP did not significantly differ from NS.

CONCLUSIONS

Enhancement of both basal and stimulated corticotrope secretion coupled with reduced adrenal sensitivity to low ACTH dose is present in AP patients without symptoms and signs of hypoadrenalism. This functional picture suggests that normal adrenal secretion is maintained due to corticotrope hyperfunction, suggesting the existence of some subclinical primary hypoadrenalism.

Neuroregulation of the hypothalamus-pituitary-adrenal (HPA) axis in humans: effects of GABA-, mineralocorticoid-, and GH-Secretagogue-receptor modulation

The hypothalamus-pituitary-adrenal (HPA) axis exerts a variety of effects at both the central and peripheral level. Its activity is mainly regulated by CRH, AVP, and the glucocorticoid-mediated feedback action. Moreover, many neurotransmitters and neuropeptides influence HPA axis activity by acting at the hypothalamic and/or suprahypothalamic level. Among them, GABA and Growth Hormone Secretagogues (GHS)/GHS-receptor systems have been shown to exert a clear inhibitory and stimulatory effect, respectively, on corticotroph secretion. Alprazolam (ALP), a GABA-A receptor agonist, shows the most marked inhibitory effect on both spontaneous and stimulated HPA axis activity, in agreement with its peculiar efficacy in panic disorders and depression where an HPA axis hyperactivation is generally present. Ghrelin and synthetic GHS possess a marked ACTH/cortisol-releasing effect in humans and the ghrelin/GHS-R system is probably involved in the modulation of the HPA response to stress and nutritional/metabolic variations. The glucocorticoid-mediated negative feedback action is mediated by both glucocorticoid (GR) and mineralocorticoid (MR) receptors activation at the central level, mainly in the hippocampus. In agreement with animal studies, MRs seem to play a crucial role in the maintenance of the circadian ACTH and cortisol rhythm, through the modulation of CRH and AVP release. GABA agonists (mainly ALP), ghrelin, as well as MR agonists/antagonists, may represent good tools to explore the activity of the HPA axis in both physiological conditions and pathological states characterized by an impaired control of the corticotroph function.

Ghrelin, hypothalamus-pituitary-adrenal (HPA) axis and Cushing's syndrome

Ghrelin, a peptide predominantly produced by the stomach, has been discovered as a natural ligand of the GH Secretagogue receptor type 1a (GHS-R1a), known as specific for synthetic GHS. Ghrelin has recently attracted considerable interest as a new orexigenic factor. However, ghrelin exerts pleiotropic actions that are explained by the widespread distribution of ghrelin and GHS-R expression. Besides strong stimulation of GH secretion, the neuroendocrine ghrelin actions also include significant stimulation of both lactotroph and corticotroph secretion; all these actions depend on acylation of ghrelin in serine-3 that allows binding and activation of the GHS-R1a. However, GHS-R subtypes are likely to exist; they also bind unacylated ghrelin that is, in fact, the most abundant circulating form and exerts some biological actions. Ghrelin secretion is mainly regulated by metabolic signals, namely inhibited by feeding, glucose and insulin while stimulated by energy restriction. The role of glucocorticoids on ghrelin synthesis and secretion is still unclear although morning ghrelin levels have been found reduced in some patients with Cushing's syndrome; this, however, would simply reflect its negative association to body mass. Ghrelin, like synthetic GHS, stimulates ACTH and cortisol secretion in normal subjects and this effect is generally sensitive to the negative glucocorticoid feedback. It is remarkable that, despite hypercortisolism, ghrelin as well as synthetic GHS display marked increase in their stimulatory effect on ACTH and cortisol secretion in patients with Cushing's disease. This is even more intriguing considering that the GH response to ghrelin and GHS is markedly reduced by glucocorticoid excess. It has been demonstrated that the ACTH-releasing effect of ghrelin and GHS is purely mediated at the central level in physiological conditions; its enhancement in the presence of ACTH-secreting tumours is, instead, likely to reflect direct action on GHS receptors present on the neoplastic tissues. In fact, peculiar ACTH hyperresponsiveness to ghrelin and GHS has been observed also in ectopic ACTH-secreting tumours.