EndoBridge 2023: highlights and pearls

EndoBridge 2023 took place on October 20-22, 2023, in Antalya, Turkey. Accredited by the European Council, the 3-day scientific program of the 11th Annual Meeting of EndoBridge included state-of-the-art lectures and interactive small group discussion sessions incorporating interesting and challenging clinical cases led by globally recognized leaders in the field and was well attended by a highly diverse audience. Following its established format over the years, the program provided a comprehensive update across all aspects of endocrinology and metabolism, including topics in pituitary, thyroid, bone, and adrenal disorders, neuroendocrine tumors, diabetes mellitus, obesity, nutrition, and lipid disorders. As usual, the meeting was held in English with simultaneous translation into Russian, Arabic, and Turkish. The abstracts of clinical cases presented by the delegates during oral and poster sessions have been published in JCEM Case Reports. Herein, we provide a paper on highlights and pearls of the meeting sessions covering a wide range of subjects, from thyroid nodule stratification to secondary osteoporosis and from glycemic challenges in post-bariatric surgery to male hypogonadism. This report emphasizes the latest developments in the field, along with clinical approaches to common endocrine issues. The 12th annual meeting of EndoBridge will be held on October 17-20, 2024 in Antalya, Turkey.

Consensus on criteria for acromegaly diagnosis and remission

PURPOSE

The 14th Acromegaly Consensus Conference was convened to consider biochemical criteria for acromegaly diagnosis and evaluation of therapeutic efficacy.

METHODS

Fifty-six acromegaly experts from 16 countries reviewed and discussed current evidence focused on biochemical assays; criteria for diagnosis and the role of imaging, pathology, and clinical assessments; consequences of diagnostic delay; criteria for remission and recommendations for follow up; and the value of assessment and monitoring in defining disease progression, selecting appropriate treatments, and maximizing patient outcomes.

RESULTS

In a patient with typical acromegaly features, insulin-like growth factor (IGF)-I > 1.3 times the upper limit of normal for age confirms the diagnosis. Random growth hormone (GH) measured after overnight fasting may be useful for informing prognosis, but is not required for diagnosis. For patients with equivocal results, IGF-I measurements using the same validated assay can be repeated, and oral glucose tolerance testing might also be useful. Although biochemical remission is the primary assessment of treatment outcome, biochemical findings should be interpreted within the clinical context of acromegaly. Follow up assessments should consider biochemical evaluation of treatment effectiveness, imaging studies evaluating residual/recurrent adenoma mass, and clinical signs and symptoms of acromegaly, its complications, and comorbidities. Referral to a multidisciplinary pituitary center should be considered for patients with equivocal biochemical, pathology, or imaging findings at diagnosis, and for patients insufficiently responsive to standard treatment approaches.

CONCLUSION

Consensus recommendations highlight new understandings of disordered GH and IGF-I in patients with acromegaly and the importance of expert management for this rare disease.

Pilot study to define criteria for Pituitary Tumors Centers of Excellence (PTCOE): results of an audit of leading international centers

PURPOSE

The Pituitary Society established the concept and mostly qualitative parameters for defining uniform criteria for Pituitary Tumor Centers of Excellence (PTCOEs) based on expert consensus. Aim of the study was to validate those previously proposed criteria through collection and evaluation of self-reported activity of several internationally-recognized tertiary pituitary centers, thereby transforming the qualitative 2017 definition into a validated quantitative one, which could serve as the basis for future objective PTCOE accreditation.

METHODS

An ad hoc prepared database was distributed to nine Pituitary Centers chosen by the Project Scientific Committee and comprising Centers of worldwide repute, which agreed to provide activity information derived from registries related to the years 2018-2020 and completing the database within 60 days. The database, provided by each center and composed of Excel® spreadsheets with requested specific information on leading and supporting teams, was reviewed by two blinded referees and all 9 candidate centers satisfied the overall PTCOE definition, according to referees' evaluations. To obtain objective numerical criteria, median values for each activity/parameter were considered as the preferred PTCOE definition target, whereas the low limit of the range was selected as the acceptable target for each respective parameter.

RESULTS

Three dedicated pituitary neurosurgeons are preferred, whereas one dedicated surgeon is acceptable. Moreover, 100 surgical procedures per center per year are preferred, while the results indicated that 50 surgeries per year are acceptable. Acute post-surgery complications, including mortality and readmission rates, should preferably be negligible or nonexistent, but acceptable criterion is a rate lower than 10% of patients with complications requiring readmission within 30 days after surgery. Four endocrinologists devoted to pituitary diseases are requested in a PTCOE and the total population of patients followed in a PTCOE should not be less than 850. It appears acceptable that at least one dedicated/expert in pituitary diseases is present in neuroradiology, pathology, and ophthalmology groups, whereas at least two expert radiation oncologists are needed.

CONCLUSION

This is, to our knowledge, the first study to survey and evaluate the activity of a relevant number of high-volume centers in the pituitary field. This effort, internally validated by ad hoc reviewers, allowed for transformation of previously formulated theoretical criteria for the definition of a PTCOE to precise numerical definitions based on real-life evidence. The application of a derived synopsis of criteria could be used by independent bodies for accreditation of pituitary centers as PTCOEs.

Unacylated ghrelin binds heparan-sulfate proteoglycans which modulate its function

Acylated ghrelin (AG) is a gut-derived peptide with growth hormone secretagogue (GHS), orexigenic and other physiological activities mediated by GHS receptor-1a (GHSR). Ghrelin occurs in unacylated form (UAG) with activities opposing AG, although its mechanism of action is unknown. UAG does not antagonize AG at GHSR, and has biological effects on cells that lack this receptor. Because UAG binds to cells, it has been hypothesized that UAG acts via a cell-surface receptor, although this has not been confirmed. This study aimed to identify cell surface proteins to which UAG binds that could modulate or mediate its biological effects. The MCF7 cell-line was used as a model because UAG induces ERK signaling in these cells in the absence of GHSR. Using ligand-receptor capture and LC-MS/MS we identified specific heparan-sulfate proteoglycans (HSPGs) to which UAG interacts on cell surfaces. In line with this, UAG, as well as AG, bind with high affinity to heparin, and heparin and heparinase treatment suppress, whereas HSPG overexpression increases, UAG binding to MCF7 cell surfaces. Moreover, heparin suppresses the ERK response to UAG. However, conversion of the lysines in UAG to alanine, which prevents its binding to heparin and cell surface HSPGs, does not prevent its activation of ERK. Our data show that the interaction of UAG with HSPGs modulates its biological activity in cells. More broadly, the interaction of UAG and AG with HSPGs could be important for the specificity and potency of their biological action in vivo.

A Pituitary Society update to acromegaly management guidelines

Guidelines and consensus statements ensure that physicians managing acromegaly patients have access to current information on evidence-based treatments to optimize outcomes. Given significant novel recent advances in understanding acromegaly natural history and individualized therapies, the Pituitary Society invited acromegaly experts to critically review the current literature in the context of Endocrine Society guidelines and Acromegaly Consensus Group statements. This update focuses on how recent key advances affect treatment decision-making and outcomes, and also highlights the likely role of recently FDA-approved therapies as well as novel combination therapies within the treatment armamentarium.

The role of AIP variants in pituitary adenomas and concomitant thyroid carcinomas in the Netherlands: a nationwide pathology registry (PALGA) study

PURPOSE

Germline mutations in the aryl-hydrocarbon receptor interacting protein (AIP) have been identified often in the setting of familial isolated pituitary adenoma (FIPA). To date there is no strong evidence linking germline AIP mutations to other neoplasms apart from the pituitary. Our primary objective was to investigate the prevalence of AIP gene mutations and mutations in genes that have been associated with neuroendocrine tumors in series of tumors from patients presenting with both pituitary adenomas and differentiated thyroid carcinomas (DTCs).

METHODS

Pathology samples were retrieved from all pituitary adenomas in patients with concomitant DTCs, including one with a known germline AIP variant. Subsequently, two additional patients with known germline AIP variants were included, of which one presented only with a follicular thyroid carcinoma (FTC).

RESULTS

In total, 17 patients (14 DTCs and 15 pituitary adenomas) were investigated by targeted next generation sequencing (NGS). The pituitary tumor samples revealed no mutations, while among the thyroid tumor samples BRAF (6/14, 42.9%) was the most frequently mutated gene, followed by NRAS (3/11, 27.3%). In one AIP-mutated FIPA kindred, the AIP-variant c.853C>T; p.Q285* was confirmed in the FTC specimen, including evidence of loss of heterozygosity (LOH) at the AIP locus in the tumor DNA.

CONCLUSION

Although most observed variants in pituitary adenomas and DTCs were similar to those of sporadic DTCs, we confirmed in one AIP mutation-positive case the AIP-variant and LOH at this locus in an FTC specimen, which raises the potential role of the AIP mutation as a rare initiating event.

A Consensus on the Diagnosis and Treatment of Acromegaly Comorbidities: An Update

OBJECTIVE

The aim of the Acromegaly Consensus Group was to revise and update the consensus on diagnosis and treatment of acromegaly comorbidities last published in 2013.

PARTICIPANTS

The Consensus Group, convened by 11 Steering Committee members, consisted of 45 experts in the medical and surgical management of acromegaly. The authors received no corporate funding or remuneration.

EVIDENCE

This evidence-based consensus was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence following critical discussion of the current literature on the diagnosis and treatment of acromegaly comorbidities.

CONSENSUS PROCESS

Acromegaly Consensus Group participants conducted comprehensive literature searches for English-language papers on selected topics, reviewed brief presentations on each topic, and discussed current practice and recommendations in breakout groups. Consensus recommendations were developed based on all presentations and discussions. Members of the Scientific Committee graded the quality of the supporting evidence and the consensus recommendations using the GRADE system.

CONCLUSIONS

Evidence-based approach consensus recommendations address important clinical issues regarding multidisciplinary management of acromegaly-related cardiovascular, endocrine, metabolic, and oncologic comorbidities, sleep apnea, and bone and joint disorders and their sequelae, as well as their effects on quality of life and mortality.

Disagreement in normative IGF-I levels may lead to different clinical interpretations and GH dose adjustments in GH deficiency

INTRODUCTION AND BACKGROUND

Normative data for the iSYS IGF-I assay have been published both in the VARIETE cohort and by Bidlingmaier et al.

OBJECTIVE

To investigate whether normative data of the VARIETE cohort lead to differences in Z-scores for total IGF-I and clinical interpretation compared to normative data of Bidlingmaier et al.

DESIGN

We used total IGF-I values previously measured by the IDS-iSYS assay in 102 GH-deficient subjects before starting GH treatment and after 12 months of GH treatment. Z-scores were calculated for all samples by using the normative data of the VARIETE cohort and by the normative data reported by Bidlingmaier et al.

RESULT

Before GH treatment, Z-scores calculated by using the normative data of the VARIETE cohort were significantly lower than those calculated by the normative data of Bidlingmaier et al: -2.40 (-4.52 to +1.31) (mean [range]) vs. -1.41 (-3.14 to +1.76); P < .001). After 12 months of GH treatment, again the Z-scores based on the normative data of the VARIETE cohort were significantly lower than those based on the normative data of Bidlingmaier et al: -0.65 (-4.32 to +2.79) vs 0.21 (-3.00 to +3.28); P < .001).

CONCLUSION

IGF-I Z-scores in 102 GH-deficient subjects differed significantly when normative data from two different sources were used. In daily clinical practice, this would most likely have led to different clinical interpretations and GH dose adjustments.

A multivariable prediction model for pegvisomant dosing: monotherapy and in combination with long-acting somatostatin analogues

BACKGROUND

Effective treatment of acromegaly with pegvisomant (PEGV), a growth hormone receptor antagonist, requires an appropriate dose titration. PEGV doses vary widely among individual patients, and various covariates may affect its dosing and pharmacokinetics.

OBJECTIVE

To identify predictors of the PEGV dose required to normalize insulin-like growth factor I (IGF-I) levels during PEGV monotherapy and in combination with long-acting somatostatin analogues (LA-SSAs).

DESIGN

Two retrospective cohorts (Rotterdam + Liège Acromegaly Survey (LAS), total n = 188) were meta-analyzed as a form of external replication to study the predictors of PEGV dosing in addition to LA-SSA, the LAS (n = 83) was used to study the predictors of PEGV monotherapy dosing. Multivariable regression models were used to identify predictors of the PEGV dose required to normalize IGF-I levels.

RESULTS

For PEGV dosing in combination with LA-SSA, IGF-I levels, weight, height and age, were associated with the PEGV normalization dosage (P ≤ 0.001, P ≤ 0.001, P = 0.028 and P = 0.047 respectively). Taken together, these characteristics predicted the PEGV normalization dose correctly in 63.3% of all patients within a range of ±60 mg/week (21.3% within a range of ±20 mg/week). For monotherapy, only weight was associated with the PEGV normalization dose (P ≤ 0.001) and predicted this dosage correctly in 77.1% of all patients within a range of ±60 mg/week (31.3% within a range of ±20 mg/week).

CONCLUSION

In this study, we show that IGF-I levels, weight, height and age can contribute to define the optimal PEGV dose to normalize IGF-I levels in addition to LA-SSA. For PEGV monotherapy, only the patient's weight was associated with the IGF-I normalization PEGV dosage.

Investigating screening for diabetes in women with a history of gestational diabetes

BACKGROUND

Type 2 diabetes mellitus (T2DM) is encountered more frequently in women with a history of gestational diabetes (GD). Screening for T2DM after pregnancy is, therefore, recommended every ≥ 1-3 years in this population. Early detection could allow for timely intervention strategies, especially in women of childbearing age. Data on adherence to diabetes screening recommendations and the prevalence of T2DM in this population are not available in the Dutch population.

AIM

To investigate the T2DM screening rate and evaluate the risk of T2DM in the five-year period following GD pregnancy.

METHODS

Single-centre survey in 85 women diagnosed with GD in 2010, using electronic medical records. Primary care physicians were asked to complete a survey regarding the screening frequency and the onset of T2DM in the five-year period following the GD pregnancy.

RESULTS

On average 33% underwent yearly screening. The screening rate, however, went up to 61.2% after primary care physicians were requested to screen this population in 2015. Of the women who were screened, 10 (19.2%) developed T2DM within five years after GD.

CONCLUSION

Current screening recommendations are poorly met, leading to missed, or delayed diagnosis of T2DM in our population. T2DM is a frequently occurring long-term complication in those who were screened in the five-year period after delivery. Optimising awareness amongst health care professionals of GD as a risk factor for T2DM is warranted and strategies to improve surveillance are necessary.

Acylated and unacylated ghrelin during OGTT in Prader-Willi syndrome: support for normal response to food intake

BACKGROUND

Prader-Willi syndrome (PWS) is characterized by hyperphagia with impaired satiety. PWS patients have very high acylated ghrelin (AG) with normal unacylated ghrelin (UAG) levels, resulting in an elevated AG/UAG ratio, suggesting an intrinsic defect in the ghrelin regulation. Normally, food intake induces satiety and a drop in AG and UAG levels, but it is unknown if these levels also decline in PWS.

OBJECTIVE

To evaluate whether the high AG levels in PWS decline in response to glucose intake during an oral glucose tolerance test (OGTT), and to investigate the effects of growth hormone (GH) treatment on this response.

METHOD

Serum levels of AG, UAG and AG/UAG ratio during an OGTT were determined in 24 GH-treated patients with PWS (median age 19·0, range 14·2-25·9 years) and in 10 GH-stop patients (of whom five were in GH-treated group; 18·5, 14·5-20·3 years).

RESULTS

In GH-treated and GH-stop young adults with PWS, there was a sharp decline of AG levels and a decrease of UAG levels in the first 30 min after the glucose load, which resulted in a lower AG/UAG ratio. GH-treated patients had significantly lower AG levels than GH-stop patients at baseline and during the OGTT. All UAG levels and AG/UAG ratios were lower in the GH-treated patients, although not significantly.

CONCLUSIONS

In young adults with PWS, an oral glucose load significantly reduces AG and UAG levels, suggesting normal regulation of the ghrelin axis by food intake. GH treatment results in lower AG levels at baseline and during OGTT, suggesting a more favourable metabolic profile. Our findings might suggest that the impaired satiety is not the result of an abnormal response of the orexigenic ghrelin to food intake.

Safety, tolerability, pharmacokinetics and pharmacodynamics of AZP-531, a first-in-class analogue of unacylated ghrelin, in healthy and overweight/obese subjects and subjects with type 2 diabetes

AIM

To explore the safety, pharmacokinetics and pharmacodynamics in humans of the unacylated ghrelin analogue AZP-531, designed to improve glycaemic control and reduce weight.

METHODS

Assessments, including glucose measurements, were performed in a three-part randomized study. In Part A, healthy subjects [n = 44, age 18-50 years, body mass index (BMI) 20-28 kg/m(2) ] received a single subcutaneous dose of 0.3, 3, 15, 30, 60 or 120 µg/kg AZP-531 or placebo. In Part B, overweight/obese subjects (n = 32, age 18-65 years, BMI 28-38 kg/m(2) ) and in Part C, patients with type 2 diabetes [T2D; n = 36, age 18-65 years, BMI 20-40 kg/m(2) , glycated haemoglobin (HbA1c) 7-10%] received AZP-531 or placebo for 14 days (daily doses of 3, 15, 30 or 60 µg/kg and 15, 2 × 30 or 60 µg/kg, respectively).

RESULTS

AZP-531 was well tolerated. Single- and multiple-dose pharmokinetic variables were similar. Maximum AZP-531 concentrations were typically reached at 1 h post-dose. Observed maximum concentration (Cmax ) and area under the curve were dose-proportional. The mean terminal half-life (t1/2 ) was 2-3 h. In Part B, AZP-531 doses of ≥15 µg/kg significantly improved glucose concentrations, without increasing insulin levels, suggesting an insulin-sensitizing effect. AZP-531 decreased mean body weight by 2.6 kg (vs 0.8 kg for placebo). In Part C, glucose variables improved in all groups, including placebo, suggesting a study effect in uncontrolled patients at baseline. Notwithstanding, AZP-531 60 µg/kg reduced HbA1c by 0.4% (vs 0.2% for placebo) and body weight by 2.1 kg (vs 1.3 kg for placebo).

CONCLUSIONS

AZP-531 was well tolerated in this first-in-human study. Its pharmacokinetic profile, suitable for once-daily dosing, and metabolic effects support further clinical development for T2D.

Long-term treatment with pegvisomant as monotherapy in patients with acromegaly: experience from ACROSTUDY

OBJECTIVE

To evaluate use of pegvisomant, a growth hormone (GH) receptor antagonist, as monotherapy in ACROSTUDY, a global safety surveillance study set in 14 countries (373 sites).

METHODS

A descriptive analysis of safety, magnetic resonance imaging (MRI) reading, and treatment outcomes in 710 subjects who received at least 1 pegvisomant dose as monotherapy during and up to 5 years follow-up in ACROSTUDY.

RESULTS

Subjects received a mean of 5.4 years of pegvisomant and were followed in ACROSTUDY for a mean of 3.8 years. A total of 1,255 adverse events (AEs) were reported in 345 subjects (48.6%). Serious AEs (SAEs) were reported in 133 (18.7%) subjects, including 22 deaths, none of which were attributed to pegvisomant use. Of 670 (94%) subjects with at least 1 liver function test (LFT) reported in ACROSTUDY, 8 (1.2%) had reported increases in transaminases >3 times the upper limit of normal (ULN). No liver failure was reported. Based on central MRI reading, 12 of 542 subjects (2.2%) had a confirmed increase or increase/decrease in tumor size. Injection-site reactions were reported in 2.3%. At 5 years of therapy, insulin-like growth factor 1 (IGF-1) level was reported normal in 67.5% (mean dose 17.2 mg/day) and elevated in 29.9% (mean dose 19.8 mg/day). Subjects on 20 mg per day or more rose from 36% at 3 years to 41% at 5 years of therapy.

CONCLUSIONS

ACROSTUDY data indicate that pegvisomant used as sole medical therapy is safe and effective for patients with acromegaly. The reported low incidence of pituitary tumor size increase and liver enzyme elevations are reassuring and support the positive benefit-risk of pegvisomant therapy.

Fractures in pituitary adenoma patients from the Dutch National Registry of Growth Hormone Treatment in Adults

PURPOSE

The effects of growth hormone (GH) replacement therapy on fracture risk in adult GH deficient (GHD) patients with different etiologies of pituitary GHD are not well known, due to limited data. The aim of this study was to investigate characteristics and fracture occurrence at start of (baseline) and during long-term GH replacement therapy in GHD adults previously treated for Cushing's disease (CD) or acromegaly, compared to patients with previous nonfunctioning pituitary adenoma (NFPA).

METHODS

From the Dutch National Registry of Growth Hormone Treatment in Adults, a nationwide surveillance study in severe GHD adults, all patients using ≥30 days of GH replacement therapy with previous NFPA (n = 783), CD (n = 180) and acromegaly (n = 65) were selected. Patient characteristics, fractures and potential influencing factors were investigated.

RESULTS

At baseline, patients with previous CD were younger, more often female and had more often a history of osteopenia or osteoporosis, whereas patients with previous acromegaly had more often received cranial radiotherapy and a longer duration between treatment of their pituitary tumor and start of adult GH replacement therapy. During follow-up, a fracture occurred in 3.8 % (n = 39) of all patients. Compared to patients with previous NFPA, only patients with previous acromegaly had an increased fracture risk after 6 years of GH replacement therapy.

CONCLUSIONS

During GH replacement therapy, an increased fracture risk was observed in severe GHD adult patients previously treated for acromegaly, but not in those previously treated for CD, compared to severe GHD adult patients using GH replacement therapy because of previous NFPA. Further studies are needed to confirm these findings and to elucidate potential underlying mechanisms.

Risk factors for subsequent endocrine-related cancer in childhood cancer survivors

Long-term adverse health conditions, including secondary malignant neoplasms, are common in childhood cancer survivors. Although mortality attributable to secondary malignancies declined over the past decades, the risk for developing a solid secondary malignant neoplasm did not. Endocrine-related malignancies are among the most common secondary malignant neoplasms observed in childhood cancer survivors. In this systematic review, we describe risk factors for secondary malignant neoplasms of the breast and thyroid, since these are the most common secondary endocrine-related malignancies in childhood cancer survivors. Radiotherapy is the most important risk factor for secondary breast and thyroid cancer in childhood cancer survivors. Breast cancer risk is especially increased in survivors of Hodgkin lymphoma who received moderate- to high-dosed mantle field irradiation. Recent studies also demonstrated an increased risk after lower-dose irradiation in other radiation fields for other childhood cancer subtypes. Premature ovarian insufficiency may protect against radiation-induced breast cancer. Although evidence is weak, estrogen-progestin replacement therapy does not seem to be associated with an increased breast cancer risk in premature ovarian-insufficient childhood cancer survivors. Radiotherapy involving the thyroid gland increases the risk for secondary differentiated thyroid carcinoma, as well as benign thyroid nodules. Currently available studies on secondary malignant neoplasms in childhood cancer survivors are limited by short follow-up durations and assessed before treatment regimens. In addition, studies on risk-modifying effects of environmental and lifestyle factors are lacking. Risk-modifying effects of premature ovarian insufficiency and estrogen-progestin replacement therapy on radiation-induced breast cancer require further study.

What is the efficacy of switching to weekly pegvisomant in acromegaly patients well controlled on combination therapy?

CONTEXT

Although combination therapy of acromegaly with long-acting somatostatin analogs (LA-SSAs) and pegvisomant (PEGV) normalizes insulin-like growth factor-1 (IGF1) levels in the majority of patients, it requires long-term adherence. Switching from combination therapy to monotherapy with weekly PEGV could improve patients' comfort, but the efficacy is unknown.

OBJECTIVE

To assess the efficacy of switching to PEGV monotherapy in patients well controlled on combination therapy of LA-SSAs and PEGV.

DESIGN

Single-center, open-label observational pilot study. LA-SSA therapy was discontinued at baseline and all patients were switched to PEGV monotherapy for 12 months. If IGF1 levels exceeded 1.0 times upper limit of normal (ULN), PEGV dose was increased by 20 mg weekly.

SUBJECTS AND METHODS

The study included 15 subjects (eight males), with a median age of 58 years (range 35-80) on combination therapy of high-dose LA-SSAs and weekly PEGV for >6 months, and IGF1 levels within the normal range. Treatment efficacy was assessed by measuring serum IGF1 levels.

RESULTS

After 12 months of weekly PEGV monotherapy, serum IGF1 levels of 73% of the subjects remained controlled. In one patient, LA-SSA had to be restarted due to recurrence of headache. IGF1 levels increased from a baseline level of 0.62 × ULN (range 0.30-0.84) to 0.83 × ULN (0.30-1.75) after 12 months, while the median weekly PEGV dose increased from 60 (30-80) mg to 80 (50-120) mg.

CONCLUSION

Our results suggest that switching from combination therapy of LA-SSAs and PEGV to PEGV monotherapy can be a viable treatment option for acromegaly patients without compromising efficacy.

Combined treatment of somatostatin analogues with pegvisomant in acromegaly

Treatment of acromegaly with monotherapy long-acting somatostatin analogues (LA-SSA) as primary treatment or after neurosurgery can only achieve complete normalization of insulin-like growth factor I (IGF-I) in roughly 40 % of patients. Recently, one of the acromegaly consensus groups has recommended switching to combined treatment of LA-SSA and pegvisomant (PEGV) in patients with partial response to LA-SSAs. This combination of LA-SSA and PEGV, a growth hormone receptor antagonist, can normalize IGF-I levels in virtually all patients, requiring that the adequate dose of PEGV is used. The required PEGV dose varies significantly between individual acromegaly patients. One of the advantages of the combination therapy is that tumor size control or even tumor shrinkage can be observed in a vast majority of patients. The main side effects of the combination treatment are gastrointestinal symptoms, lipohypertrophy and transient elevated liver transaminases. In this review we provide an overview of the efficacy and safety of the combined treatment of LA-SSAs with PEGV.

The effect of hypopituitarism on fatigue after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Aneurysmal subarachnoid hemorrhage (SAH) survivors often complain of fatigue, which is disabling. Fatigue is also a common symptom of pituitary dysfunction (PD), in particular in patients with growth hormone deficiency (GHD). A possible association between fatigue after SAH and long-term pituitary deficiency in SAH survivors has not yet been established.

METHODS

A single center observational study was conducted amongst 84 aneurysmal SAH survivors to study the relationship between PD and fatigue over time after SAH, using mixed model analysis. Fatigue was measured with the Fatigue Severity Scale and its relationships with other clinical variables were studied.

RESULTS

Three-quarters of respondents (76%) have pathological fatigue directly after SAH and almost two-thirds (60%) of patients still have pathological levels of fatigue after 14 months. The severity of SAH measured with a World Federation of Neurosurgical Societies (WFNS) score higher than 1 (P = 0.008) was associated with long-term fatigue. There is no statistically significant effect of PD (P = 0.8) or GHD (P = 0.23) on fatigue in SAH survivors over time.

CONCLUSIONS

Fatigue is a common symptom amongst SAH survivors. WFNS is a usable clinical determinant of fatigue in SAH survivors. Neither PD nor GHD has a significant effect on long-term fatigue after SAH.

Elevated ratio of acylated to unacylated ghrelin in children and young adults with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is characterized by a switch from failure to thrive to excessive weight gain and hyperphagia in early childhood. Hyperghrelinemia may be involved in the underlying mechanisms of the switch. The purpose of this study is to evaluate acylated ghrelin (AG) and unacylated ghrelin (UAG) levels in PWS and investigate their associations with hyperphagia. This is a cross-sectional clinical study conducted in three PWS expert centers in the Netherlands and France. Levels of AG and UAG and the AG/UAG ratio were determined in 138 patients with PWS (0.2-29.4 years) and compared with 50 age-matched obese subjects (4.3-16.9 years) and 39 healthy controls (0.8-28.6 years). AEBSF was used to inhibit deacylation of AG. As a group, PWS patients had higher AG but similar UAG levels as healthy controls (AG 129.1 vs 82.4 pg/ml, p = 0.016; UAG 135.3 vs 157.3 pg/ml, resp.), resulting in a significantly higher AG/UAG ratio (1.00 vs 0.61, p = 0.001, resp.). Obese subjects had significantly lower AG and UAG levels than PWS and controls (40.3 and 35.3 pg/ml, resp.), but also a high AG/UAG ratio (1.16). The reason for the higher AG/UAG ratio in PWS and obese was, however, completely different, as PWS had a high AG and obese a very low UAG. PWS patients without weight gain or hyperphagia had a similar AG/UAG ratio as age-matched controls, in contrast to those with weight gain and/or hyperphagia who had an elevated AG/UAG ratio. The switch to excessive weight gain in PWS seems to coincide with an increase in the AG/UAG ratio, even prior to the start of hyperphagia.

Pegvisomant in combination with long-acting somatostatin analogues in acromegaly: the role of the GH receptor deletion of exon 3

BACKGROUND

Doses of the GH receptor (GHR) antagonist pegvisomant (PEGV) that normalize insulin-like growth factor 1 (IGF1) levels vary widely among acromegaly patients. Predictors for PEGV response are baseline IGF1 levels, sex, body weight and previous radiotherapy. A GHR polymorphism lacking exon 3 (d3-GHR) is frequent in the general population. The influence of d3-GHR on PEGV responsiveness in acromegaly is unclear.

OBJECTIVE

To assess the influence of d3-GHR on IGF1 levels and PEGV responsiveness in acromegaly patients using combined PEGV and long-acting somatostatin receptor ligand (LA-SRIF) treatment.

DESIGN

Data were collected at the Rotterdam Pituitary Centre between 2004 and 2013. Patients with elevated IGF1 levels (>1.2 upper limit of normal; n=112) and over 6 months of high-dose LA-SRIF treatment were co-treated with PEGV. GHR genotype was assessed using genomic DNA in 104 patients.

RESULTS

D3-GHR was observed in 51 (49.0%) of the patients (7.7% homozygous, 41.3% heterozygous) and was in Hardy-Weinberg equilibrium (P=0.859). Baseline characteristics were similar in d3-GHR and full-length (fl)-GHR genotypes. During PEGV/LA-SRIF treatment IGF1 levels were not different between d3-carriers and non-carriers. Similarly, no difference in PEGV dose required to normalize IGF1 (P=0.337) or PEGV serum levels (P=0.433) was observed between the two groups. However, adenoma size decreased significantly (>20% of largest diameter) in 25.6% of the fl-GHR genotype but only in 7.5% of d3-carriers (P=0.034, OR: 4.6 (CI: 1.1-18.9)).

CONCLUSIONS

GHR genotype does not predict the IGF1 normalizing dose of PEGV in acromegaly patients using combination PEGV/LA-SRIF treatment. However, fewer d3-carriers showed significant reductions in adenoma size.

Review of current and emerging treatment options in acromegaly

In almost every patient, acromegaly is caused by a growth hormone secreting pituitary adenoma. Clinical features are the result of excessive growth hormone secretion and the consecutive excess in insulin-like growth factor I levels. This results in somatic overgrowth and metabolic disturbances with a higher morbidity and mortality than in the general population. With optimal disease management, mortality can be reduced to that seen in the general population. The current treatment of acromegaly is based on a combination of surgery, radiotherapy and medical therapy. This review provides an overview of the current and upcoming therapies with a focus on medical therapy.

Pituitary dysfunction after aneurysmal subarachnoid haemorrhage: course and clinical predictors—the HIPS study

OBJECTIVE

We describe the occurrence and course of anterior pituitary dysfunction (PD) after aneurysmal subarachnoid haemorrhage (SAH), and identify clinical determinants for PD in patients with recent SAH.

METHODS

We prospectively collected demographic and clinical parameters of consecutive survivors of SAH and measured fasting state endocrine function at baseline, 6 and 14 months. We included dynamic tests for growth-hormone function. We used logistic regression analysis to compare demographic and clinical characteristics of patients with SAH with and without PD.

RESULTS

84 patients with a mean age of 55.8 (±11.9) were included. Thirty-three patients (39%) had PD in one or more axes at baseline, 22 (26%) after 6 months and 6 (7%) after 14 months. Gonadotropin deficiency in 29 (34%) patients and growth hormone deficiency (GHD) in 26 (31%) patients were the most common deficiencies. PD persisted until 14 months in 6 (8%) patients: GHD in 5 (6%) patients and gonadotropin deficiency in 4 (5%). Occurrence of a SAH-related complication was associated with PD at baseline (OR 2.6, CI 2.2 to 3.0). Hydrocephalus was an independent predictor of PD 6 months after SAH (OR 3.3 CI 2.7 to 3.8). PD was associated with a lower score on health-related quality of life at baseline (p=0.06), but not at 6 and 14 months.

CONCLUSIONS

Almost 40% of SAH survivors have PD. In a small but substantial proportion of patients GHD or gonadotropin deficiency persists over time. Hydrocephalus is independently associated with PD 6 months after SAH.

TRIAL REGISTRATION NUMBER

NTR 2085.

Pregnancy in acromegaly patients treated with pegvisomant

To summarize all available data on pregnancy outcome of acromegaly patients exposed to the growth hormone receptor antagonist pegvisomant (PEGV) during pregnancy as present in the Pfizer's Global Safety Database. Pfizer's Global Safety Database contains adverse event data obtained from the following sources: spontaneous reports, health authorities, Pfizer-sponsored post-marketing surveillance program (ACROSTUDY), customer engagement programs, and clinical studies, reported regardless of outcome. The safety database was searched up to 10th March 2014. From the 35 pregnancy cases, 27 involved maternal [mean age (range) 33.3 years (23-41) and 8 paternal (33.7 years (32-38)] PEGV exposure. Two female patients were reported with two pregnancy cases each. Fetal outcome was normal in 14 (4 paternal) of the 18 reported as live birth, while 4 cases (1 paternal) did not specify the birth outcome. At conception, PEGV mean dose (range) was 15.3 mg/d (4.3-30). In 3 cases of maternal exposure of the 18 cases reporting live birth, PEGV was continued throughout the pregnancy in a dose of 12.1 mg/d (10-15). In 5 cases (all maternal) an elective termination of the pregnancy was performed with no reported fetal abnormalities, 2 cases (maternal) reported a non-PEGV-related spontaneous abortion and in 1 maternal case an ectopic pregnancy occurred. In 9 cases (3 paternal), the fetal outcome was not reported. Three women reported gestational diabetes; one woman continued PEGV treatment during pregnancy. Although the number of reported pregnancies with exposure to PEGV is very small, the presented data reflect the largest series of data available to date and do not suggest adverse consequences of PEGV on pregnancy outcome. Nevertheless, it should be stressed that PEGV should not be used during pregnancy unless absolutely necessary.

Changes in circulating IGF1 receptor stimulating activity do not parallel changes in total IGF1 during GH treatment of GH-deficient adults

CONTEXT

Previously we demonstrated that IGF1 receptor stimulating activity (IGF1RSA) offers advantages in diagnostic evaluation of adult GH deficiency (GHD). It is unknown whether IGF1RSA can be used to monitor GH therapy.

OBJECTIVE

To investigate the value of circulating IGF1RSA for monitoring GH therapy.

DESIGN/METHODS

106 patients (54 m; 52 f) diagnosed with GHD were included; 22 were GH-naïve, 84 were already on GH treatment and discontinued therapy 4 weeks before baseline values were established. IGF1RSA was determined by the IGF1R kinase receptor activating assay, total IGF1 by immunoassay (Immulite). GH doses were titrated to achieve total IGF1 levels within the normal range.

RESULTS

After 12 months, total IGF1 and IGF1RSA increased significantly (total IGF1 from 8.1 (95% CI 7.3-8.9) to 14.9 (95% CI 13.5-16.4) nmol/l and IGF1RSA from 115 (95% CI 104-127) to 181 (95% CI 162-202) pmol/l). After 12 months, total IGF1 normalized in 81% of patients, IGF1RSA in 51% and remained below normal in more than 40% of patients in whom total IGF1 had normalized.

CONCLUSIONS

During 12 months of GH treatment, changes in IGF1RSA did not parallel changes in total IGF1. Despite normalization of total IGF1, IGF1RSA remained subnormal in a considerable proportion of patients. At present our results have no short-term consequences for GH therapy of GHD patients. However, based on our findings we propose future studies to examine whether titrating GH dose against IGF1RSA results in a better clinical outcome than titrating against total IGF1.

Tumor Recurrence or Regrowth in Adults With Nonfunctioning Pituitary Adenomas Using GH Replacement Therapy

CONTEXT

GH replacement therapy (GH-RT) is a widely accepted treatment in GH-deficient adults with nonfunctioning pituitary adenoma (NFPAs). However, some concerns have been raised about the safety of GH-RT because of its potentially stimulating effect on tumor growth.

OBJECTIVE

The aim of this study was to evaluate tumor progression in NFPA patients using GH-RT.

DESIGN, SETTING, AND PATIENTS

From the Dutch National Registry of Growth Hormone Treatment in Adults, a nationwide surveillance study in severely GH-deficient adults (1998-2009), all NFPA patients with ≥ 30 days of GH-RT were selected (n = 783). Data were retrospectively collected from the start of GH-RT in adulthood (baseline).

MAIN OUTCOME MEASURE

Tumor progression, including tumor recurrence after complete remission at baseline and regrowth of residual tumor.

RESULTS

Tumor progression developed in 12.1% of the patients after a median (range) time of 2.2 (0.1-14.9) years. Prior radiotherapy decreased tumor progression risk compared to no radiotherapy (hazard ratio = 0.16; 95% confidence interval, 0.09-0.26). Analysis in 577 patients with available baseline imaging data showed that residual tumor at baseline increased tumor progression risk compared to no residual tumor (hazard ratio = 4.5; 95% confidence interval, 2.4-8.2).

CONCLUSIONS

The findings in this large study were in line with those reported in literature and provide further evidence that GH-RT does not appear to increase tumor progression risk in NFPA patients. Although only long-term randomized controlled trials will be able to draw firm conclusions, our data support the current view that GH-RT is safe in NFPA patients.

Ghrelin

BACKGROUND

The gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism.

SCOPE OF REVIEW

In this review, we discuss the diverse biological functions of ghrelin, the regulation of its secretion, and address questions that still remain 15 years after its discovery.

MAJOR CONCLUSIONS

In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct areas including learning and memory, gut motility and gastric acid secretion, sleep/wake rhythm, reward seeking behavior, taste sensation and glucose metabolism.

Cerebrovascular events, secondary intracranial tumors, and mortality after radiotherapy for nonfunctioning pituitary adenomas: a subanalysis from the Dutch National Registry of Growth Hormone Treatment in Adults

CONTEXT

Radiotherapy is frequently administered as adjuvant treatment in patients with clinically nonfunctioning pituitary adenomas (NFPAs). However, concerns have been raised about potential long-term side effects, including cerebrovascular events (CVEs) and secondary intracranial tumors.

OBJECTIVE

The aim of this study was to analyze the risk of CVEs, secondary intracranial tumors, and mortality in irradiated (IRR) NFPA patients, compared with NFPA patients who were not irradiated (non-IRR).

DESIGN, SETTING, AND PATIENTS

The study cohort included 806 patients with a NFPA from the Dutch National Registry of Growth Hormone Treatment in Adults, a nationwide long-term surveillance study in severe GH-deficient adult patients. IRR patients (n = 456) were compared with non-IRR patients (n = 350).

MAIN OUTCOME MEASURES

CVEs, secondary intracranial tumors, and mortality were measured.

RESULTS

Sixty-nine subjects developed a CVE. In men, but not in women, the incidence of a CVE was significantly higher in IRR patients than in non-IRR patients (hazard ratio 2.99, 95% confidence interval 1.31-6.79). A secondary intracranial tumor developed in five IRR patients and two non-IRR patients. After adjustment for age, radiotherapy was not associated with mortality.

CONCLUSIONS

The incidence of secondary intracranial tumors and mortality did not differ between IRR and non-IRR patients. However, a CVE was found significantly more frequently in IRR men but not in women. Further research into the long-term effects of cranial radiotherapy seems mandatory. The potential risks of radiotherapy have to be taken into account when radiotherapy is considered in NFPA patients, and long-term follow-up is recommended.

The introduction of the IDS-iSYS total IGF-1 assay may have far-reaching consequences for diagnosis and treatment of GH deficiency

CONTEXT

IGF-1 measurements are used for screening and monitoring GH deficiency (GHD) and acromegaly.

OBJECTIVE

Our objective was to study whether the introduction of the IDS-iSYS IGF-1 assay would lead to different clinical interpretations in GHD and acromegaly.

DESIGN

In 106 GHD subjects and in 15 acromegalic subjects visiting our university hospital, total IGF-1 levels were measured before and during therapy by using the Immulite (IM) assay and IDS-iSYS (ID) assay. Z-scores were calculated by using assay-specific age-specific normative range values. All treatment decisions were based upon results obtained by the IM assay.

RESULTS

In GHD subjects, absolute IGF-1 concentrations differed significantly between both IGF-1 assays before treatment (P < .001) but not during GH treatment (P = .32), and mean Z-scores for IGF-1 differed significantly before starting (IM, -2.23, vs ID, -1.43; P < .001) and during GH treatment (IM, -0.60, vs ID, +0.21; P < .001). In acromegalic subjects, absolute IGF-1 concentrations did not differ between both IGF-1 assays before treatment (P = .18) but were significantly different during treatment (P = 0.009), and mean Z-scores for IGF-1 were not different before starting (IM, 10.93, vs ID, 10.78; P = .41) or during treatment (IM, 3.60, vs ID, 3.18; P = .23).

CONCLUSIONS

In GHD subjects, mean IGF-1 Z-scores significantly differed when measured by the IM assay compared with the ID assay irrespective of treatment. In contrast, in acromegaly, mean IGF-1 Z-scores did not differ significantly between both assays. Our study suggests that replacement of the IM assay by the ID assay may have far-reaching consequences for the clinical diagnosis and treatment of GHD.

Long-term efficacy and safety of pegvisomant in combination with long-acting somatostatin analogs in acromegaly

BACKGROUND

Treatment for acromegaly patients with long-acting somatotropin release-inhibiting factor (LA-SRIF) often does not result in complete normalization of IGF-1. Addition of pegvisomant (PEGV), a GH receptor antagonist, could improve this; however, the literature has not described long-term follow-up.

OBJECTIVE

To assess long-term efficacy and safety of this combined treatment in the largest current single-center cohort of patients, from 2004-2013.

DESIGN

Acromegaly patients were treated for at least 6 months with a high-dose LA-SRIF. To patients with persistently elevated IGF-1 levels (>1.2 × upper limit of normal) or poor quality of life, PEGV was added as one weekly injection.

RESULTS

The patients (n = 141) were treated with PEGV and LA-SRIFs for a median period of 4.9 years (range, 0.5-9.2). Efficacy, defined as the lowest measured IGF-1 level during treatment, was 97.0%. The median PEGV dose to achieve this efficacy was 80 mg weekly (interquartile range, 60-120 mg). Combination treatment-related adverse events were recorded in 26 subjects (18.4%). Pituitary tumor size increase was observed in one patient. Injection-site reactions were observed in four subjects. In 19 patients (13.5%), transiently elevated liver transaminases of more than three times the upper limit of normal were observed, of which 83% occurred within the first year of combination treatment. Eight patients died, at a mean age of 71 years; none of them were considered treatment-related.

CONCLUSIONS

The combination treatment with LA-SRIFs and PEGV was effective in 97% of the patients, it appears to be a safe medical treatment and it reduces the required dose of PEGV.

Development of potent selective competitive-antagonists of the melanocortin type 2 receptor

Cushing's disease, a hypercortisolemic state induced by an ACTH overexpressing pituitary adenoma, causes increased morbidity and mortality. Selective antagonism of the melanocortin type 2 receptor (MC2R) may be a novel treatment modality. Five structurally related peptides with modified HFRW sites but intact putative MC2R binding sites were tested for antagonistic activity at MC1R, MC2R/MRAP, MC3R, MC4R and MC5R. Two of these peptides (GPS1573 and GPS1574) dose-dependently antagonized ACTH-stimulated MC2R activity (IC50s of 66±23 nM and 260±1 nM, respectively). GPS1573 and 1574 suppressed the Rmax but not EC50 of ACTH on MC2R, indicating non-competitive antagonism. These peptides did not antagonize α-MSH stimulation of MC1R and antagonized MC3, 4 and 5R at markedly lower potency. GP1573 and GPS1574 antagonize MC4R with IC50s of 950 nM and 3.7 μM, respectively. In conclusion, two peptide antagonists were developed with selectivity for MC2R, forming a platform for development of a medical treatment for Cushing's disease.

Differentiating between Cushing's disease and pseudo-Cushing's syndrome: comparison of four tests

OBJECTIVE

To evaluate the diagnostic performance of four different tests in order to differentiate between Cushing's disease (CD) and pseudo-Cushing's syndrome (PCS).

METHODS

In this prospective study, a total of 73 patients with clinical features of hypercortisolism and insufficient suppression of serum cortisol after 1 mg overnight dexamethasone and/or an elevated excretion of cortisol in 24-h urine samples were included. The circadian rhythm of serum cortisol levels as well as midnight serum cortisol (MserC) levels were assessed in all 73 patients. Late-night salivary cortisol (LNSC) concentrations were obtained in 44 patients. The dexamethasone-CRH (Dex-CRH) test was performed in 54 patients.

RESULTS

FIFTY-THREE PATIENTS WERE DIAGNOSED WITH CD AND SUBSEQUENTLY TREATED. TWENTY PATIENTS WERE CLASSIFIED AS HAVING PSC. SERUM CORTISOL CIRCADIAN RHYTHM: the diurnal rhythmicity of cortisol secretion was retained in PCS. A cortisol midnight:morning ratio of >0.67 is highly suggestive of CD (positive predictive value (PPV) 100% and negative predictive value (NPV) 73%). MserC concentration >243 nmol/l has a PPV of 98% in predicting true CD (NPV 95%). LNSC level >9.3 nmol/l predicted CD in 94% of patients (NPV 100%). Dex-CRH test: after 2 days of dexamethasone suppression, a CRH-stimulated cortisol level >87 nmol/l (T=15 min) resulted in a PPV of 100% and an NPV of 90%.

CONCLUSION

The Dex-CRH test as well as a single measurement of cortisol in serum or saliva at late (mid-) night demonstrated high diagnostic accuracy in differentiating PCS from true CD.

Pasireotide versus octreotide in acromegaly: a head-to-head superiority study

CONTEXT

Biochemical control reduces morbidity and increases life expectancy in patients with acromegaly. With current medical therapies, including the gold standard octreotide long-acting-release (LAR), many patients do not achieve biochemical control.

OBJECTIVE

Our objective was to demonstrate the superiority of pasireotide LAR over octreotide LAR in medically naive patients with acromegaly.

DESIGN AND SETTING

We conducted a prospective, randomized, double-blind study at 84 sites in 27 countries.

PATIENTS

A total of 358 patients with medically naive acromegaly (GH >5 μg/L or GH nadir ≥1 μg/L after an oral glucose tolerance test (OGTT) and IGF-1 above the upper limit of normal) were enrolled. Patients either had previous pituitary surgery but no medical treatment or were de novo with a visible pituitary adenoma on magnetic resonance imaging.

INTERVENTIONS

Patients received pasireotide LAR 40 mg/28 days (n = 176) or octreotide LAR 20 mg/28 days (n = 182) for 12 months. At months 3 and 7, titration to pasireotide LAR 60 mg or octreotide LAR 30 mg was permitted, but not mandatory, if GH ≥2.5μg/L and/or IGF-1 was above the upper limit of normal.

MAIN OUTCOME MEASURE

The main outcome measure was the proportion of patients in each treatment arm with biochemical control (GH <2.5 μg/L and normal IGF-1) at month 12.

RESULTS

Biochemical control was achieved by significantly more pasireotide LAR patients than octreotide LAR patients (31.3% vs 19.2%; P = .007; 35.8% vs 20.9% when including patients with IGF-1 below the lower normal limit). In pasireotide LAR and octreotide LAR patients, respectively, 38.6% and 23.6% (P = .002) achieved normal IGF-1, and 48.3% and 51.6% achieved GH <2.5 μg/L. 31.0% of pasireotide LAR and 22.2% of octreotide LAR patients who did not achieve biochemical control did not receive the recommended dose increase. Hyperglycemia-related adverse events were more common with pasireotide LAR (57.3% vs 21.7%).

CONCLUSIONS

Pasireotide LAR demonstrated superior efficacy over octreotide LAR and is a viable new treatment option for acromegaly.

In active acromegaly, IGF1 bioactivity is related to soluble Klotho levels and quality of life

The value of measuring IGF1 bioactivity in active acromegaly is unknown. Soluble Klotho (S-Klotho) level is elevated in active acromegaly and it has been suggested that S-Klotho can inhibit activation of the IGF1 receptor (IGF1R). A cross-sectional study was carried out in 15 patients with active acromegaly based on clinical presentation, unsuppressed GH during an oral glucose tolerance test, and elevated total IGF1 levels (>+2 s.d.). Total IGF1 was measured by immunoassay, IGF1 bioactivity by the IGF1R kinase receptor activation assay and S-Klotho by an ELISA. Quality of Life (QoL) was assessed by Acromegaly QoL (AcroQoL) Questionnaire and Short-Form-36 Health Survey Questionnaire (SF-36). Out of 15 patients, nine had IGF1 bioactivity values within the reference range. S-Klotho was higher in active acromegaly compared with controls. Age-adjusted S-Klotho was significantly related to IGF1 bioactivity (r=0.75, P=0.002) and to total IGF1 (r=0.62, P=0.02). IGF1 bioactivity and total IGF1 were inversely related to the physical component summary of the SF-36 (r=-0.78, P=0.002 vs r=-0.60, P=0.03). Moreover, IGF1 bioactivity, but not total IGF1, was significantly inversely related to the physical dimension of the AcroQoL Questionnaire (r=-0.60, P=0.02 vs r=-0.37, P=0.19). In contrast to total IGF1, IGF1 bioactivity was within the reference range in a considerable number of subjects with active acromegaly. Elevated S-Klotho levels may have reduced IGF1 bioactivity. Moreover, IGF1 bioactivity was more strongly related to physical measures of QoL than total IGF1, suggesting that IGF1 bioactivity may better reflect physical limitations perceived in active acromegaly.

Cortisol diurnal rhythm and quality of life after successful medical treatment of Cushing's disease

Cushing's disease (CD) is associated with severely impaired quality of life (QoL). Moreover, the physiological cortisol diurnal rhythm (CDR) is disturbed in CD. QoL can improve after successful surgery, the primary treatment for CD. We evaluated the effects of medical treatment on QoL and CDR. In 17 patients, stepwise medical treatment was applied with the somatostatin analog pasireotide, the dopamine agonist cabergoline and the adrenal-blocking agent ketoconazole. After 80 days, 15/17 (88%) patients had reached normal urinary free cortisol excretion (UFC). Subsequently, patients continued medical therapy or underwent surgery. UFC, plasma and salivary CDR and QoL-related parameters (assessed using 5 questionnaires: Nottingham Health Profile, Hospital Anxiety and Depression Scale, Multidimensional Fatigue Index-20, RAND-36, CushingQoL) were measured. At baseline, 5/17 patients had preserved CDR. In 6/12 patients with disturbed baseline CDR, recovery was observed, but without any correlation with QoL. QoL was significantly impaired according to 18/20 subscales in CD patients compared to literature-derived controls. According to the RAND-36 questionnaire, patients reported more pain at day 80 (p < 0.05), which might reflect steroid-withdrawal. Generally, QoL did not improve or deteriorate after 80 days. CushingQoL scores seemed to improve after 1 year of remission in three patients that continued medical therapy (p = 0.11). CDR can recover during successful pituitary- and adrenal-targeted medical therapy. Patients with CD have impaired QoL compared to controls. Despite the occurrence of side-effects, QoL does not deteriorate after short-term biochemical remission induced by medical therapy, but might improve after sustained control of hypercortisolism.

Final height and IGF1 in adult survivors of Wilms tumour

OBJECTIVE

One-sided nephrectomy is followed by increased levels of IGF1, associated with linear growth during childhood. The aim was to evaluate final height and IGF1 levels in nephrectomized Wilms tumour survivors when compared with healthy Dutch references and survivors of other cancer types.

DESIGN

Cross-sectional retrospective study.

METHODS

Data of 575 adult childhood cancer survivors were analysed. median follow-up time was 17.8 (range 5.048.8) years. Analysis of (co)variance was performed to evaluate differences between subgroups: nephrectomized Wilms survivors treated with or without abdominal irradiation (n=41 and n=36) and survivors of other cancer types treated with or without irradiation involving the cranium, abdomen or total body (n=149 and n=349). Main outcome measures were IGF1 and height, expressed as SDS.

RESULTS

After adjustment for age at diagnosis, former corticosteroid treatment and renal impairment, height SDS in non-irradiated nephrectomized Wilms survivors was significantly higher than that in non-irradiated survivors of other cancer types (estimated mean SDS -0.09 vs -0.49, P=0.044), abdominal irradiated survivors (SDS -0.70, P=0.015) and other irradiated survivors (SDS -1.47, P<0.001). Non-irradiated nephrectomized Wilms tumour survivors had significantly higher IGF1 SDS than other irradiated survivors (estimated mean SDS -0.05 vs -1.36, P<0.001 and 0.11 vs 1.37, P<0.001), while there was no significant difference with the other two subgroups.

CONCLUSIONS

Adult survivors of Wilms tumour showed better attainment of final height and relatively higher IGF1 levels than those of other cancer types who had significantly shorter stature and lower IGF1 levels than Dutch references.

Diagnostic value of a ghrelin test for the diagnosis of GH deficiency after subarachnoid hemorrhage

OBJECTIVE

To determine the diagnostic value of a ghrelin test in the diagnosis of GH deficiency (GHD) shortly after aneurysmal subarachnoid hemorrhage (SAH).

DESIGN

Prospective single-center observational cohort study.

METHODS

A ghrelin test was assessed after the acute phase of SAH and a GH-releasing hormone (GHRH)-arginine test 6 months post SAH. Primary outcome was the diagnostic value of a ghrelin test compared with the GHRH-arginine test in the diagnosis of GHD. The secondary outcome was to assess the safety of the ghrelin test, including patients' comfort, adverse events, and idiosyncratic reactions.

RESULTS

Forty-three survivors of SAH were included (15 males, 35%, mean age 56. 6 ± 11.7). Six out of 43 (14%) SAH survivors were diagnosed with GHD by GHRH-arginine test. In GHD subjects, median GH peak during ghrelin test was significantly lower than that of non-GHD subjects (5.4 vs 16.6, P=0.002). Receiver operating characteristics analysis showed an area under the curve of 0.869. A cutoff limit of a GH peak of 15 μg/l corresponded with a sensitivity of 100% and a false-positive rate of 40%. No adverse events or idiosyncratic reactions were observed in subjects undergoing a ghrelin test, except for one subject who reported flushing shortly after ghrelin infusion.

CONCLUSION

Owing to its convenience, validity, and safety, the ghrelin test might be a valuable GH provocative test, especially in the early phase of SAH.

Desacyl ghrelin is influenced by changes in insulin concentration during an insulin tolerance test

OBJECTIVE

Ghrelin, a gut-brain peptide, regulates energy homeostasis and glucose metabolism and is present in acylated and nonacylated form in the circulation. Although desacyl ghrelin (DAG), the predominant form of ghrelin, is associated with insulin sensitivity and improved metabolic state, not much is known about its direct regulation by insulin. We aimed to assess changes in DAG in response to the rapid increase in insulin concentration during an insulin tolerance test (ITT) in normal weight and obese subjects.

DESIGN

We performed an observational single center study. An ITT was assessed in eight subjects (four males), median age of 29.9 years (range 19.6-42.0). DAG concentrations were measured at 20, 40, 60 and 90 min after insulin infusion. Homeostatic Model Assessment (HOMA) was calculated from fasting insulin and glucose. Body mass index (BMI) and waist circumference were assessed.

RESULTS

Three subjects were obese (BMI ≥ 30 kg/m(2)), one subject was overweight (BMI = 25-30 kg/m(2)) and four subjects had normal weight (BMI = 18.5-25 kg/m(2)). Median DAG decreased after insulin infusion (90 pg/mL, p = 0.028), especially in normal weight subjects. Baseline DAG was lower in subjects with higher BMI (ρ = -0.76, p = 0.028) and higher fasting insulin (ρ = -0.76, p = 0.030). DAG changes correlated with fasting insulin levels (ρ = -0.85, p = 0.007), HOMA (ρ = -0.86, p = 0.007), BMI (ρ = -0.83, p = 0.010) and waist circumference (ρ = -0.93, p < 0.001).

CONCLUSION

DAG levels rapidly decreased in response to insulin administration in normal subjects, but not in insulin-resistant obese who are in a state of relative DAG deficiency.

Decreased ovarian function is associated with obesity in very long-term female survivors of childhood cancer

OBJECTIVE

Obesity and gonadal dysfunction are known major side effects of treatment in adult childhood cancer survivors (CCS). In the general population, obesity has a negative influence on female fertility. We aimed to evaluate whether obesity and serum insulin are associated with decreased ovarian reserve markers in CCS.

DESIGN

Retrospective single-center cohort study.

METHODS

Data of 191 female survivors of childhood cancer were analyzed. Median follow-up time was 18.8 (2.348.8) years. Outcome measures were serum anti-Müllerian hormone (AMH) and total follicle count (FC). Potential risk factors were: BMI; body composition measures, determined by dual-energy X-ray absorptiometry (total fat percentage, lean body mass, and visceral fat percentage); and fasting insulin.

RESULTS

Lower serum AMH was found in obese subjects (β (%) -49, P=0.007) and in subjects with fasting insulin in the highest tertile (β (%) -43, P=0.039). Total fat percentage tends to be associated with serum AMH (β (%) -2.1, P=0.06). Survivors in the highest tertile of insulin had significantly lower FC than survivors in the lowest tertile (β -6.3, P=0.013). BMI and other measures of body composition were not associated with FC. Correlation between serum AMH and antral follicle count (AFC) was ρ=0.32 (P=0.08).

CONCLUSIONS

Obesity and insulin resistance are associated with gonadal damage, as reflected by decreased AMH and reduced FC in adult survivors of childhood cancer. In contrast to its highly predictive value for AFC in the healthy female population, serum AMH does not seem to correlate as well with AFC in CCS.

Metabolic effects of overnight continuous infusion of unacylated ghrelin in humans

OBJECTIVE

To clarify the metabolic effects of an overnight i.v. infusion of unacylated ghrelin (UAG) in humans. UAG exerts relevant metabolic actions, likely mediated by a still unknown ghrelin receptor subtype, including effects on β-cell viability and function, insulin secretion and sensitivity, and glucose and lipid metabolism.

DESIGN

We studied the effects of a 16-h infusion (from 2100 to 1300  h) of UAG (1.0  μg/kg per h) or saline in eight normal subjects (age (mean±s.e.m.), 29.6±2.4 years; body mass index (BMI), 22.4±1.7  kg/m(2)), who were served, at 2100 and 0800  h respectively, with isocaloric balanced dinner and breakfast. Glucose, insulin, and free fatty acid (FFA) levels were measured every 20  min.

RESULTS

In comparison with saline, UAG induced significant (P<0.05) changes in glucose, insulin, and FFA profiles. UAG infusion decreased glucose area under the curve (AUC) values by 10% (UAG(0 - 960  min): 79.0±1.7×10(3)  mg/dl per min vs saline(0- 960  min): 87.5±3.8×10(3)  mg/dl per min) and the AUC at night by 14% (UAG(180)(-)(660  min): 28.4±0.5×10(3)  mg/dl per min vs saline(180 - 660  min): 33.2±1.1×10(3)  mg/dl per min). The overall insulin AUC was not significantly modified by UAG infusion; however, insulin AUC observed after meals was significantly increased under the exposure to UAG with respect to saline at either dinner or breakfast. The FFA AUC values were decreased by 52% under the exposure to UAG in comparison with saline (UAG(0 - 960  min): 0.3±0.02×10(3)  mEq/l per min vs saline(0 - 960  min): 0.6±0.05×10(3)  mEq/l per min).

CONCLUSIONS

Exposure to the i.v. administration of UAG improves glucose metabolism and inhibits lipolysis in healthy volunteers. Thus, in contrast to the diabetogenic action of AG, UAG displays hypoglycemic properties.

Long-term safety of pegvisomant in patients with acromegaly: comprehensive review of 1288 subjects in ACROSTUDY

CONTEXT

Pegvisomant is a GH receptor antagonist. The ACROSTUDY is a global safety surveillance study of long-term treatment of acromegaly with pegvisomant.

OBJECTIVE

The objective of the study was to monitor long-term safety and treatment outcomes.

DESIGN

ACROSTUDY is open to all patients with acromegaly who are treated with pegvisomant. We report an interim analysis of data captured from 1288 subjects enrolled before a database freeze of December 31, 2009.

SETTING

This was a global noninterventional surveillance study.

MAIN OUTCOME MEASURE(S)

Long-term monitoring of safety, including central magnetic resonance imaging (MRI) reading and treatment outcomes, was measured.

RESULTS

Subjects (n = 1288) were treated with pegvisomant for a mean of 3.7 yr and followed up in ACROSTUDY for a mean of 2.1 yr. A total of 1147 adverse events (AE) were recorded in 477 subjects (37%), among which 192 AE in 124 subjects (9.6%) were considered to be related to pegvisomant. Serious AE were recorded in 159 subjects (12.3%), whereas pegvisomant-related Serious AE were recorded in 26 subjects (2%). No deaths (15 subjects; 1.2%) were attributed to pegvisomant use. The incidence of increase in pituitary tumor size in the subset with confirmed MRI increases on central reading represented 3.2% of the overall cohort with at least two available MRI (n = 936). Injection-site reactions were reported in 28 cases (2.2%). In 30 patients (2.5%), an elevated aspartate aminotransferase or alanine aminotransferase of more than 3 times the upper level of normality was reported. There were no reports of liver failure. After 5 yr of pegvisomant treatment, 63.2% of subjects had normal IGF-I levels at a mean dose of 18 mg/d.

CONCLUSIONS

Data entered and evaluated in ACROSTUDY indicate that pegvisomant is an effective and safe medical treatment in patients with acromegaly. The reported low incidence of pituitary tumor size increase, liver enzyme elevations, and lipodystrophy at the injection site are reassuring.

What is active acromegaly and which parameters do we have?

Disease activity of acromegaly can be measured in many ways. Growth hormone (GH) and insulin-like growth factor 1 (IGF1) concentrations are the main biochemical markers used to measure the response to treatment. Both GH and IGF1 have been associated with prognosis, in particular mortality. In this review, we discuss the available parameters to assess disease activity in acromegaly.

Effects of chronic slow release-lanreotide treatment on insulin-like growth factor system and metabolic parameters in acromegalic patients

Insulin and IGF binding protein (IGFBP)-1 are linked by negative association. Somatostatin (SS) reduces insulin secretion by acting on pancreatic β-cell and also by decreasing GH secretion. SS analogues in acromegaly reduce total IGF-I levels inhibiting GH hypersecretion, but they also reduce free IGF-I bioactivity increasing IGFBP-1 levels by inducing insulin decrease. In 13 acromegalic patients we studied GH, IGF system, insulin, and glucagon levels at baseline and at 7 days, 1 and 6 months under treatment with slow release (SR)-lanreotide (LAN) (60 mg im monthly). The hormonal and metabolic response to arginine (ARG) (0.5 g/kg iv in 30 min) was also studied at each time point. LAN decreased GH, total IGF-I, and IGFBP-3 levels at each time point. Insulin and glucagon levels were reduced, while IGFBP-1 and free IGF-I levels were increased by LAN at day 7 and after 1 month only. LAN did not modify the GH, insulin, glucagon, glucose, and IGFBP-1 responses to ARG. At each time point ARG-induced insulin increase was coupled to increase in glucagon and IGFBP-1 levels. This study shows that acromegalic patients under chronic treatment with LAN display: a) inhibition of GH and total IGF-I levels, not coupled to persistent decrease in free IGF-I levels; b) persistent decrease in IGFBP- 3 but transient decrease and increase in insulin and IGFBP- 1, respectively; c) unchanged hormonal and metabolic response to ARG. Our findings also show that ARG stimulates IGFBP-1 despite marked increase in insulin secretion; this escape from the negative relationship linking insulin and IGFBP- 1 would likely reflect the ARG-induced glucagon increase.

The hypercoagulable state in Cushing's disease is associated with increased levels of procoagulant factors and impaired fibrinolysis, but is not reversible after short-term biochemical remission induced by medical therapy

CONTEXT

Cushing's disease (CD) is accompanied by an increased risk of venous thromboembolism. Surgery is the primary treatment of CD.

OBJECTIVE

The aim of the study was to compare hemostatic parameters between patients with CD and controls and to evaluate the effect of medical treatment of CD on hemostasis.

DESIGN AND SETTING

During 80 d, stepwise medical treatment was applied with the somatostatin analog pasireotide, the dopamine agonist cabergoline, and ketoconazole, which suppresses adrenocortical steroidogenesis, at four university medical centers in The Netherlands.

PATIENTS

Seventeen patients with de novo, residual, or recurrent CD were included.

MAIN OUTCOME MEASURES

We measured urinary free cortisol and parameters of coagulation and fibrinolysis.

RESULTS

Patients with CD had significantly higher body mass index (P < 0.001), shortened activated partial thromboplastin time (P < 0.01), and higher levels of fibrinogen, Factor VIII, and protein S activity (P < 0.05) compared to healthy control subjects. In addition, fibrinolytic capacity was impaired in patients with CD as reflected by prolonged clot lysis time (P < 0.001) and higher levels of plasminogen activator inhibitor type 1, thrombin-activatable fibrinolysis inhibitor, and α2-antiplasmin (P < 0.01). There were no statistically significant differences in von Willebrand factor:antigen, antithrombin, and protein C activity. After 80 d, 15 of 17 patients had normalized urinary free cortisol excretion. Despite biochemical remission, only slight decreases in antithrombin (P < 0.01) and thrombin-activatable fibrinolysis inhibitor (P < 0.05) levels were observed. Other parameters of coagulation and fibrinolysis did not change significantly.

CONCLUSIONS

The hypercoagulable state in patients with CD, which is explained by both increased production of procoagulant factors and impaired fibrinolysis, is not reversible upon short-term biochemical remission after successful medical therapy. This may have implications for the duration of anticoagulant prophylaxis in patients with (cured) CD.

Pegvisomant and improvement of quality of life in acromegalic patients

BACKGROUND

Acromegaly is a growth disorder, but mostly it is a metabolic disease related to excessive production of growth hormone (GH). It is characterized by progressive somatic disfigurement in combination with sometimes severe systemic manifestations. Long-acting somatostatin analog (SSA) therapy normalizes serum insulin-like growth factor I (IGF-I) levels in approximately 55% of patients, but we postulate that these patients still have acromegaly in many tissues other than the liver. Direct and indirect effects of SSA reduce hepatic IGF-I generation and make the liver behave as if it is GH resistant. The remaining 'peripheral' or non- hepatic acromegaly has a significant negative impact on the quality of life of these patients.

CONCLUSIONS

Pegvisomant is the most effective medical treatment for acromegaly. Due to its mode of action and pharmacodynamic properties, it is the ideal partner for combination therapy with an SSA for acromegalic patients with a remaining, peripheral form of the disease.

Rapid decrease in adrenal responsiveness to ACTH stimulation after successful pituitary surgery in patients with Cushing's disease

OBJECTIVE

The aim of this study was to investigate the effects of transsphenoidal surgery (TS) on the adrenal sensitivity to ACTH (adrenocorticotropin) stimulation in patients with Cushing's disease (CD).

METHODS

We measured the cortisol response to 1 μg synthetic ACTH (1-24) 6 days after pituitary surgery in 45 patients with CD. Mean follow-up period was 56·5 months (SE 4·7).

RESULTS

In 24 of 28 patients in sustained remission after pituitary surgery, peak cortisol concentrations below 774 nm (28·0 μg/dl) were recorded after stimulation with 1 μg synthetic ACTH (86%). Two patients with recurrent disease after initial remission (late relapse) also showed ACTH-stimulated peak cortisol levels below 774 nM. Fourteen of 15 patients with persistent CD after surgery (early failure) showed absolute peak cortisol levels >774 nm in response to ACTH stimulation.

CONCLUSION

Patients in remission after pituitary surgery for CD showed a rapid decrease of adrenal responsiveness to exogenous ACTH stimulation. This phenomenon may be explained by ACTH-receptor down-regulation in the adrenal cortex after complete removal of the pituitary corticotroph adenoma. In our study, the postoperative low-dose ACTH stimulation test had a sensitivity of 93% and a specificity of 87% in predicting immediate remission of CD after pituitary surgery.

Ghrelin and glucose homeostasis

Ghrelin plays an important physiological role in modulating GH secretion, insulin secretion and glucose metabolism. Ghrelin has direct effects on pancreatic islet function. Also, ghrelin is part of a mechanism that integrates the physiological response to fasting. However, pharmacologic studies indicate the important obesogenic/diabetogenic properties of ghrelin. This is very likely of physiological relevance, deriving from a requirement to protect against seasonal periods of food scarcity by building energy reserves, predominantly in the form of fat. Available data indicate the potential of ghrelin blockade as a means to prevent its diabetogenic effects. Several studies indicate a negative correlation between ghrelin levels and the incidence of type 2 diabetes and insulin resistance. However, it is unclear if low ghrelin levels are a risk factor or a compensatory response. Direct antagonism of the receptor does not always have the desired effects, however, since it can cause increased body weight gain. Pharmacological suppression of the ghrelin/des-acyl ghrelin ratio by treatment with des-acyl ghrelin may also be a viable alternative approach which appears to improve insulin sensitivity. A promising recently developed approach appears to be through the blockade of GOAT activity, although the longer term effects of this treatment remain to be investigated.