Guidelines for the treatment of growth hormone excess and growth hormone deficiency in adults

High prevalence of morphometric vertebral fractures opportunistically detected on thoracic radiograms in patients with non-functioning pituitary adenoma

PURPOSE

Vertebral fractures (VFs), the hallmark of skeletal fragility, have been reported as an emerging complication in patients with pituitary diseases associated with hormonal excess and/or deficiency, independently from bone mineral density. Non-functioning pituitary adenoma (NFPA) is amongst the most frequent pituitary adenomas; however, skeletal health in this context has never been investigated. We aimed at assessing the prevalence and the determinants of morphometric VFs in patients with NFPA.

METHODS

We enrolled 156 patients (79 M/77F, mean age 55.75 ± 12.94 years) at admission in Neurosurgery Unit before trans-sphenoidal surgery and compared them with an age and sex-matched control group of subjects with neither history/risk factors for secondary osteoporosis nor pituitary disorders. We performed a vertebral morphometric evaluation of the thoracic spine on pre-operative X-ray images (MTRx) and collected biochemical, demographic, and clinical data from the entire cohort.

RESULTS

The prevalence of thoracic VFs in patients with NFPA was significantly higher than the control group (26.3% vs. 10.3%; p < 0.001). In the NFPA group, 20 patients (48.8% of the fractured patients) showed multiple VFs, 14 (34.1% of them) showed moderate/severe VFs. Patients with VFs were significantly older and had lower serum free triiodothyronine (fT3) levels than non-fractured ones (p = 0.002 and p = 0.004; respectively). The prevalence of secondary male hypogonadism was higher among men with VFs as compared to those with no VFs (72% vs. 48.1%; p = 0.047). Consistently, total testosterone levels in males were significantly lower in fractured patients than in non-fractured ones (p = 0.02). The prevalence of gonadotroph adenomas was significantly higher among patients with VFs (p = 0.02). In multiple logistic regression analysis, older age and lower serum fT3 levels were independent factors predicting the risk for VFs.

CONCLUSIONS

For the first time, we reported a high prevalence of thoracic radiological VFs in patients with NFPAs. Our data should prompt clinicians to proceed with a clinical bone fragility evaluation already during the diagnostic work-up, particularly in those with concomitant hypogonadism, or in those with older age and/or with lower fT3.

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.

Development of a Novel Algorithm to Identify People with High Likelihood of Adult Growth Hormone Deficiency in a US Healthcare Claims Database

OBJECTIVE

Adult growth hormone deficiency (AGHD) is an underdiagnosed disease associated with increased morbidity and mortality. Identifying people who may benefit from growth hormone (GH) therapy can be challenging, as many AGHD symptoms resemble those of aging. We developed an algorithm to potentially help providers stratify people by their likelihood of having AGHD.

DESIGN

The algorithm was developed with, and applied to, data in the anonymized Truven Health MarketScan® claims database. Patients. A total of 135 million adults in the US aged ≥18 years with ≥6 months of data in the Truven database. Measurements. Proportion of people with high, moderate, or low likelihood of having AGHD, and differences in demographic and clinical characteristics among these groups.

RESULTS

Overall, 0.5%, 6.0%, and 93.6% of people were categorized into groups with high, moderate, or low likelihood of having AGHD, respectively. The proportions of females were 59.3%, 71.6%, and 50.4%, respectively. People in the high- and moderate-likelihood groups tended to be older than those in the low-likelihood group, with 58.3%, 49.0%, and 37.6% aged >50 years, respectively. Only 2.2% of people in the high-likelihood group received GH therapy as adults. The high-likelihood group had a higher incidence of comorbidities than the low-likelihood group, notably malignant neoplastic disease (standardized difference -0.42), malignant breast tumor (-0.27), hyperlipidemia (-0.26), hypertensive disorder (-0.25), osteoarthritis (-0.23), and heart disease (-0.22).

CONCLUSIONS

This algorithm may represent a cost-effective approach to improve AGHD detection rates by identifying appropriate patients for further diagnostic testing and potential GH replacement treatment.

Traumatic Brain Injury as Frequent Cause of Hypopituitarism and Growth Hormone Deficiency: Epidemiology, Diagnosis, and Treatment

Traumatic brain injury (TBI)-related hypopituitarism has been recognized as a clinical entity for more than a century, with the first case being reported in 1918. However, during the 20^th century hypopituitarism was considered only a rare sequela of TBI. Since 2000 several studies strongly suggest that TBI-mediated pituitary hormones deficiency may be more frequent than previously thought. Growth hormone deficiency (GHD) is the most common abnormality, followed by hypogonadism, hypothyroidism, hypocortisolism, and diabetes insipidus. The pathophysiological mechanisms underlying pituitary damage in TBI patients include a primary injury that may lead to the direct trauma of the hypothalamus or pituitary gland; on the other hand, secondary injuries are mainly related to an interplay of a complex and ongoing cascade of specific molecular/biochemical events. The available data describe the importance of GHD after TBI and its influence in promoting neurocognitive and behavioral deficits. The poor outcomes that are seen with long standing GHD in post TBI patients could be improved by GH treatment, but to date literature data on the possible beneficial effects of GH replacement therapy in post-TBI GHD patients are currently scarce and fragmented. More studies are needed to further characterize this clinical syndrome with the purpose of establishing appropriate standards of care. The purpose of this review is to summarize the current state of knowledge about post-traumatic GH deficiency.

GH Replacement in the Elderly: Is It Worth It?

Growth hormone (GH), once the age of linear growth is completed, continues to play a fundamental role for the human body. In adulthood, GH contributes to regulate muscle, cardiovascular and bone metabolism. The same happens in old age, although there is less data on the effect of GH in the elderly. Regardless the age of onset, a reduced quality of life (QoL), an increased cardiovascular risk and an accelerated age-related decline in physical strength have been demonstrated in the elderly with GH deficiency (EGHD). In adults with GH deficiency (AGHD), recent studies suggest a role of GH replacement therapy (GHrt) in improving lean/fat mass ratio, blood pressure, lipid profile, bone metabolism and QoL. Despite these recent studies, there is still a lack of randomized controlled trials proving these positive effects in EGHD. Moreover, the lack of a long-term positive outcome on mortality, and the cost of GHrt could often impact on treatment decision-making and lead to postpone or avoid the prescription. The aim of this mini-review is to summarize the available data on GHrt in EGHD, in order to highlight its weaknesses and strengths and to provide directions to clinicians that will help in the management of this specific set of patients.

Untreated adult GH deficiency is not associated with the development of metabolic risk factors: a long-term observational study

PURPOSE

Uncertainties exist about the predictors of the severity of the clinical picture of GH deficiency (GHD) syndrome. Aim of the study was to evaluate, in adult patients with GHD, the predictors of the development of hypercholesterolemia, hypertension, diabetes mellitus, and osteoporosis.

METHODS

We retrospectively studied 327 adult patients (age 47.1 ± 17.1 years) with untreated severe GHD (mean follow-up 110.9 ± 56.8 months). GHD was defined by GHRH + arginine test using BMI cut-offs. The possible development of hypercholesterolemia, hypertension, diabetes mellitus, and osteoporosis was investigated by Kaplan-Meier survival analysis. For each clinical outcome, either a univariate or multivariate analysis according to the Cox proportional-hazards model was performed to identify those factors that were associated with the development of the event.

RESULTS

GH secretion parameters were not associated with the outcomes. Hypercholesterolemia was positively and negatively predicted by a BMI ≥ 30 kg/m² (HR 2.50, p 0.00) and the dose of l-thyroxine possibly in place (HR 0.98, p 0.02), respectively. Hypertension was positively predicted by a BMI ≥ 30 kg/m² (HR 2.64, p 0.00) and IGF-I SDS values (HR 2.26, p 0.00). Diabetes mellitus was positively predicted by hypertension (HR 11.76, p 0.01). Osteoporosis was positively and negatively predicted by hypercholesterolemia (HR 3.25, p 0.01) and hypertension (HR 0.21, p 0.00), respectively.

CONCLUSIONS

The severity of the impairment of GH secretion does not predict the development of the clinical picture of GHD syndrome: untreated adult GHD does not increase the development of metabolic risk factors in hypopituitaric patients.

Incidence rate and risk factors of early repolarization in patients with growth hormone-secreting pituitary adenoma: a cohort study

Purpose

To investigate the incidence and risk factors for early repolarization (ER) in patients with growth hormone (GH)-secreting pituitary adenomas.

Methods

From August 2014 to August 2016, patients with GH-secreting pituitary adenomas and non-functioning pituitary adenomas admitted to the First Affiliated Hospital, Sun Yat-sen University, were prospectively enrolled. Logistic regression analysis was used to investigate risk factors for ER development.

Results

A total of 118 patients with GH-secreting pituitary adenomas (41 with concomitant ER) and 103 patients with non-functioning pituitary adenomas were included. Compared with the non-functioning adenoma group GH and IGF-1 levels, left ventricular mass index (LVMI), and incidence of ER were significantly higher in the GH-secreting pituitary adenoma group (all P<0.05). LVMI was an independent risk factor for ER. Bivariate correlation analysis showed that course of disease, GH, IGF-1, and diabetes were correlated with LVMI. Course of disease and IGF-1 were directly correlated with LVMI. Two-year follow-up of patients who underwent transsphenoidal resection showed that incidence of ER was significantly decreased in patients with normal GH and IGF-1 levels.

Conclusion

Compared with non-functioning pituitary adenoma patients, patients with GH-secreting pituitary adenomas have a significantly higher incidence of ER. Elevation of serum GH and IGF-1 had positive correlations with cardiac muscle cell hypertrophy and increased LVMI.

Pituitary Diseases and Bone

Neuroendocrinology of bone is a new area of research based on the evidence that pituitary hormones may directly modulate bone remodeling and metabolism. Skeletal fragility associated with high risk of fractures is a common complication of several pituitary diseases such as hypopituitarism, Cushing disease, acromegaly, and hyperprolactinemia. As in other forms of secondary osteoporosis, pituitary diseases generally affect bone quality more than bone quantity, and fractures may occur even in the presence of normal or low-normal bone mineral density as measured by dual-energy X-ray absorptiometry, making difficult the prediction of fractures in these clinical settings. Treatment of pituitary hormone excess and deficiency generally improves skeletal health, although some patients remain at high risk of fractures, and treatment with bone-active drugs may become mandatory. The aim of this review is to discuss the physiological, pathophysiological, and clinical insights of bone involvement in pituitary diseases.

Effects of pegvisomant and somatostatin receptor ligands on incidence of vertebral fractures in patients with acromegaly

PURPOSE

Acromegalic osteopathy is an emerging complication of acromegaly characterized by increase in bone turnover, deterioration in bone microarchitecture and high risk of vertebral fractures (VFs). Somatostatin receptor ligands (SRLs) and pegvisomant (PegV) are used for treatment of acromegaly and there is evidence that both drugs may exert direct effects on peripheral targets regardless of biochemical control of disease. However, whether or not SRLs and PegV may directly influence skeletal health its is unknown.

METHODS

In this longitudinal study, we evaluated the incidence of radiological VFs in 83 patients (48 females, 35 males; median age 47 years, range 18-80 years) who were treated with SRLs alone (42 cases), PegV alone (6 cases) or in combination with SRLs (35 cases) for median period of 82 months (range 36-126). PegV was given when acromegaly was not controlled by SRLs alone.

RESULTS

During the follow-up, 29 patients (34.9%) developed incident VFs. In patients receiving PegV due to active disease during SRL therapy, incidence of VFs decreased significantly from 43.9 to 26.8% (p = 0.039). When acromegaly was controlled by PegV, the incidence of VFs was slightly but not significantly lower as compared to that observed in patients with biochemical control of disease by SRLs (10.0 vs. 26.7%; p = 0.09). In the multivariate logistic regression analysis, incident VFs were independently predicted by pre-existing VFs (odds ratio 61.0; p = 0.009), duration of active acromegaly (odds ratio 1.01; p = 0.05) and mean serum IGF-I during the follow-up (odds ratio 5.26; p = 0.03), regardless of the therapeutic regimen (odds ratio 1.05; p = 0.94).

CONCLUSIONS

PegV and SRLs had comparable effects on VF risk in acromegaly. The activity of disease was the main determinant of VFs independently of the drug used to control acromegaly.

How to improve effectiveness of pegvisomant treatment in acromegalic patients

PURPOSE

Pegvisomant (PEGV) treatment in acromegaly patients resistant to somatostatin analogues is less effective in the real life than in clinical trials. This is a multicenter, observational, retrospective, longitudinal study. The aim was to detect characteristics which improve long-term PEGV effectiveness.

METHODS

87 acromegalic patients treated with PEGV have been enrolled in seven referral Italian centres. PEGV was administered for up to 4 years, at doses up titrated until IGF-1 normalization or to ≥ 30 mg/day. The rate of patients who reached IGF-1 normalization at last visit has been calculated.

RESULTS

IGF-1 was normalized in 75.9% of patients after 1 year and in 89.6% at last visit. Disease control was associated with lower baseline GH, IGF-1 and IGF-1 xULN and was more frequent when baseline IGF-1 was < 2.7 × ULN (p < 0.02). PEGV dose was dependent on baseline IGF-1 > 2.7 × ULN (p < 0.05) and doses > 1.0 mg/BMI/day were administered more frequently when baseline IGF-1 was > 2.0 × ULN (p = 0.03). PEGV resistance was associated with higher BMI (p = 0.006) and was more frequent when BMI was > 30 kg/m² (p = 0.07). There were no significant differences between patients treated with monotherapy or combined treatment. IGF-1 normalization, PEGV dose and rate of associated treatment were similar between males and females. PEGV effectiveness was independent from previous management. Diabetic patients needed higher doses of PEGV than non-diabetic ones.

CONCLUSIONS

PEGV effectiveness improves when up titration is appropriate. Higher PEGV doses at start and a more rapid up-titration are necessary in patients with obesity and/or IGF-1 > 2.7 × ULN.

MANAGEMENT OF ENDOCRINE DISEASE: Risk of overtreatment in patients with adrenal insufficiency: current and emerging aspects

The effects of long-term replacement therapy of adrenal insufficiency (AI) are still a matter of controversy. In fact, the established glucocorticoid replacement regimens do not completely reproduce the endogenous hormonal production and the monitoring of AI treatment may be a challenge for the lack of reliable clinical and biochemical markers. Consequently, several AI patients are frequently exposed to relative glucocorticoid excess potentially leading to develop chronic complications, such as diabetes mellitus, dyslipidemia, hypertension and fragility fractures with consequent impaired QoL and increased mortality risk. This review deals with the pathophysiological and clinical aspects concerning the over-replacement therapy of primary and secondary AI.

[Diagnostics and treatment of acromegaly : Necessity for targeted monitoring of comorbidities]

Acromegaly is a rare and severe condition, presenting with typical signs and symptoms. The diagnosis is often initially made years after the first manifestations of the disease. In more than 99% of patients the disease is caused by a benign pituitary tumor that secretes growth hormone (GH). The diagnosis is based on the presence of increased insulin-like growth factor 1 (IGF-1) levels and a lack of GH suppression in the oral glucose tolerance test. The standard imaging procedure for tumor detection is magnetic resonance imaging in the region of the sella turcica. Treatment includes surgical, drug and radiation therapy. Important factors are an intensive aftercare of the patient, controls for detection of tumor recurrence and pituitary insufficiency as well as assessment of various organ functions and risk constellations. Patient care should involve close cooperation between endocrinologists, neurosurgeons and general practitioners as well as other specialist disciplines.

Role of Mass Spectrometry in Clinical Endocrinology

The advent of mass spectrometry into the clinical laboratory has led to an improvement in clinical management of several endocrine diseases. Liquid chromatography tandem mass spectrometry found some of its first clinical applications in the diagnosis of inborn errors of metabolism, in quantitative steroid analysis, and in drug analysis laboratories. Mass spectrometry assays offer analytical sensitivity and specificity that is superior to immunoassays for many analytes. This article highlights several areas of clinical endocrinology that have witnessed the use of liquid chromatography tandem mass spectrometry to improve clinical outcomes.

Pegvisomant in acromegaly: an update

BACKGROUND

In 2007, we published an opinion document to review the role of pegvisomant (PEG) in the treatment of acromegaly. Since then, new evidence emerged on the biochemical and clinical effects of PEG and on its long-term efficacy and safety.

AIM

We here reviewed the emerging aspects of the use of PEG in clinical practice in the light of the most recent literature.

RESULTS

The clinical use of PEG is still suboptimal, considering that it remains the most powerful tool to control IGF-I in acromegaly allowing to obtain, with a pharmacological treatment, the most important clinical effects in terms of signs and symptoms, quality of life and comorbidities. The number of patients with acromegaly exposed to PEG worldwide has become quite elevated and the prolonged follow-up allows now to deal quite satisfactorily with many clinical issues including major safety issues, such as the concerns about possible tumour (re)growth under PEG. The positive or neutral impact of PEG on glucose metabolism has been highlighted, and the clinical experience, although limited, with sleep apnoea and pregnancy has been reviewed. Finally, the current concept of somatostatin receptor ligands (SRL) resistance has been addressed, in order to better define the acromegaly patients to whom the PEG option may be offered.

CONCLUSIONS

PEG increasingly appears to be an effective and safe medical option for many patients not controlled by SRL but its use still needs to be optimized.

Growth hormone deficiency in treated acromegaly and active Cushing's syndrome

Growth hormone deficiency (GHD) in adults is characterized by reduced quality of life and physical fitness, skeletal fragility, increased weight and cardiovascular risk. It may be found in (over-) treated acromegaly as well as in active Cushing's syndrome. Hypopituitarism may develop in patients after definitive treatment of acromegaly, although the exact prevalence of GHD in this population is still uncertain because of limited awareness, and scarce and conflicting data so far available. Because GHD associated with acromegaly and Cushing's syndrome may yield adverse consequences on similar target systems, the final outcomes of some complications of both acromegaly and Cushing's syndrome may be further affected by the occurrence of GHD. It is still largely unknown, however, whether GHD in patients with post-acromegaly or active Cushing's syndrome (e.g. pharmacologic glucocorticoid treatment) may benefit from GH replacement. We review the diagnostic, clinical and therapeutic aspects of GHD in adults treated for acromegaly and in those with active Cushing's syndrome.

Somatostatin analogs, cabergoline and pegvisomant: comparing the efficacy of medical treatment for acromegaly

Therapies for acromegaly aim at normalizing hormonal excess and controlling tumor growth . Therapeutic approaches are surgery, pharmacotherapy and radiotherapy. Area covered: This review focuses on the role of medical therapy of acromegaly, comparing the efficacy of somatostatin analogues (SSA), dopamine-agonists (DA) and pegvisomant (PEG), the three available drug classes for treating acromegaly. To clarify the difference in response rates reported in the literature for these therapies, we performed a search for original articles published in PubMed. SSA represent the first-line approach to medical treatment. This therapy is effective in controlling acromegaly in about 40% of patients, however there are great differences in the reported hormonal efficacy of SSA in the different series. In patients partially resistant to SSA, cabergoline can be added when hormonal levels are close to normalization, resulting effective in control IGF-I levels in 43% of patients. In patients with higher hormonal levels PEG is indicated, normalizing IGF-I levels in 79.8% and 80.6% of cases when used in monotherapy or in combination with SSA. Pasireotide, the newly developed SSA multi-ligand receptor, represents a new option in SSA resistant patients. Expert commentary: Medical therapy represents an important therapeutic option resulting safe and effective in controlling acromegaly in a high percentage of patients. The best treatment should be individually tailored for each patient, taking into account sex, age, comorbidities, tumor characteristics and hormonal levels.

High-resolution-cone beam tomography analysis of bone microarchitecture in patients with acromegaly and radiological vertebral fractures

Vertebral fractures are an emerging complication of acromegaly but their prediction is still difficult occurring even in patients with normal bone mineral density. In this study we evaluated the ability of high-resolution cone-beam computed tomography to provide information on skeletal abnormalities associated with vertebral fractures in acromegaly. 40 patients (24 females, 16 males; median age 57 years, range 25-72) and 21 healthy volunteers (10 females, 11 males; median age 60 years, range: 25-68) were evaluated for trabecular (bone volume/trabecular volume ratio, mean trabecular separation, and mean trabecular thickness) and cortical (thickness and porosity) parameters at distal radius using a high-resolution cone-beam computed tomography system. All acromegaly patients were evaluated for morphometric vertebral fractures and for mineral bone density by dual-energy X-ray absorptiometry at lumbar spine, total hip, femoral neck, and distal radius. Acromegaly patients with vertebral fractures (15 cases) had significantly (p < 0.05) lower bone volume/trabecular volume ratio, greater mean trabecular separation, and higher cortical porosity vs. nonfractured patients, without statistically significant differences in mean trabecular thickness and cortical thickness. Fractured and nonfractured acromegaly patients did not have significant differences in bone density at either skeletal site. Patients with acromegaly showed lower bone volume/trabecular volume ratio (p = 0.003) and mean trabecular thickness (p < 0.001) and greater mean trabecular separation (p = 0.02) as compared to control subjects, without significant differences in cortical thickness and porosity. This study shows for the first time that abnormalities of bone microstructure are associated with radiological vertebral fractures in acromegaly. High-resolution cone-beam computed tomography at the distal radius may be useful to evaluate and predict the effects of acromegaly on bone microstructure.

Mass spectrometry-based approaches to targeted quantitative proteomics in cardiovascular disease

Mass spectrometry-based proteomics methodology has become an important tool in elucidating some of the underlying mechanisms involved in cardiovascular disease. The present review provides details on selected important protein targets where highly selective and specific mass spectrometry-based approaches have led to important new findings and provided new mechanistic information. The role of six proteins involved in the etiology of cardiovascular disease (acetylated platelet cyclooxygenase-1, serum apolipoprotein A1, apolipoprotein C-III, serum C-reactive protein, serum high mobility group box-1 protein, insulin-like growth factor I) and their quantification has been discussed. There are an increasing number of examples where highly selective mass spectrometry-based quantification has provided new important data that could not be obtained with less labor intensive and cheaper immunoassay-based procedures. It is anticipated that these findings will lead to significant advances in a number of important issues related to the role of specific proteins in cardiovascular disease. The availability of a new generation of high-resolution high-sensitivity mass spectrometers will greatly facilitate these studies so that in the future it will be possible to analyze serum proteins of relevance to cardiovascular disease with levels of specificity and/or sensitivity that cannot be attained by immunoassay-based procedures.

New medical therapies of acromegaly

Acromegaly is a rare disease associated with significant morbidity and increased mortality. Treatment of acromegaly aims at controlling growth hormone hypersecretion, improving patients' symptoms and comorbidities and normalizing mortality. The therapeutic options for acromegaly include surgery, medical therapies and radiotherapy. However, despite all these treatment options, approximately one-half of patients are not adequately controlled. Progress in molecular research has made possible to develop new therapeutic strategies to improve control of acromegaly. This article will review the new medical approaches to acromegaly which consist in evolution of traditional therapeutic protocols and development of new molecules with different profiles of activity.

Current and Emerging Aspects of Diabetes Mellitus in Acromegaly

Diabetes mellitus is a frequent complication of acromegaly, a disease characterized by chronic hypersecretion of growth hormone (GH) by a pituitary adenoma. Diabetes occurs commonly but not only as a consequence of an insulin-resistant state induced by GH excess. The development of diabetes in patients with acromegaly is clinically relevant, since such a complication is thought to increase the already elevated cardiovascular morbidity and mortality risk of the disease. Emerging data suggest that a specific cardiomyopathy can be identified in acromegaly patients with diabetes. Moreover, the presence of diabetes may also influence therapeutic decision making in acromegaly, since traditional and newly developed drugs used in this clinical setting may impact glucose metabolism regardless of control of GH hypersecretion.

Current and future medical treatments for patients with acromegaly

INTRODUCTION

Acromegaly is a relatively rare condition of growth hormone (GH) excess associated with significant morbidity and, when left untreated, high mortality. Therapy for acromegaly is targeted at decreasing GH and insulin-like growth hormone 1 levels, ameliorating patients' symptoms and decreasing any local compressive effects of the pituitary adenoma. The therapeutic options for acromegaly include surgery, medical therapies (such as dopamine agonists, somatostatin receptor ligands and the GH receptor antagonist pegvisomant) and radiotherapy. However, despite all these treatments option, approximately 50% of patients are not adequately controlled.

AREAS COVERED

In this paper, the authors discuss: 1) efficacy and safety of current medical therapy 2) the efficacy and safety of the new multireceptor-targeted somatostatin ligand pasireotide 3) medical treatments currently under clinical investigation (oral octreotide, ITF2984, ATL1103), and 4) preliminary data on the use of new injectable and transdermal/transmucosal formulations of octreotide.

EXPERT OPINION

This expert opinion supports the need for new therapeutic agents and modalities for patients with acromegaly.

Incidence of morphometric vertebral fractures in adult patients with growth hormone deficiency

Cross-sectional studies showed an elevated prevalence of clinical and morphometric vertebral fractures (VFs) in adult patients with growth hormone deficiency (GHD). However, no data are available on incidence and determinants of radiological VFs in this clinical setting. In this prospective study, we investigated the incidence and risk factors of radiological VFs in adults with GHD. Forty patients with GHD (28 males, 12 females; median age 44 years, range 19-82) were studied for incident VFs using quantitative morphometric approach on spine X-ray at baseline and after 6 years of follow-up. GHD patients were also studied for bone mineral density (BMD) measured by DXA at lumbar spine. After 6 years of follow-up, 12 patients (30 %) experienced incident VFs. Patients with incident VFs had more frequently untreated GHD and prevalent VFs at baseline, as compared to patients who did not experience incident VFs. Untreated GHD patients were significantly older as compared to treated GHD (50 years, range 19-82 vs. 36 years, range 19-75; p = 0.003), but the correlation between high risk of VFs and untreated GHD remained significant even after adjustment for the age of patients (odds ratio 6.8, CI 95 % 1.1-41.8; p = 0.037). In GHD patients experiencing incident VFs, lumbar spine BMD decreased significantly whereas it did not change in patients not developing VFs. This is the first prospective study confirming the hypothesis suggested by cross-sectional studies that untreated GHD may cause high risk of VFs in adult patients and that recombinant human GH treatment may effectively decrease such a risk.

Quantitation of Insulin-Like Growth Factor 1 in Serum by Liquid Chromatography High Resolution Accurate-Mass Mass Spectrometry

Insulin-like growth factor 1 (IGF-1) is a 70 amino acid peptide hormone which acts as the principal mediator of the effects of growth hormone (GH). Due to a wide variability in circulating concentration of GH, IGF-1 quantitation is the first step in the diagnosis of GH excess or deficiency. Majority (>95 %) of IGF-1 circulates as a ternary complex along with its principle binding protein insulin-like growth factor 1 binding protein 3 (IGFBP-3) and acid labile subunit. The assay design approach for IGF-1 quantitation has to include a step to dissociate IGF-1 from its ternary complex. Several commercial assays employ a buffer containing acidified ethanol to achieve this. Despite several modifications, commercially available immunoassays have been shown to have challenges with interference from IGFBP-3. Additionally, inter-method comparison between IGF-1 immunoassays has been shown to be suboptimal. Mass spectrometry has been utilized for quantitation of IGF-1. In this chapter a liquid chromatography high resolution accurate-mass mass spectrometry (LC-HRAMS) based method for IGF-1 quantitation has been described.

Prevalence of AIP mutations in a series of Turkish acromegalic patients: are synonymous AIP mutations relevant?

CONTEXT

In sporadic acromegaly, overall AIP(mut) prevalence is reported as 3, 4.1 and 16 % in studies carried out across Europe. However, it is not known whether the prevalence shows any changes across different ethnicities. The aim of the study was to identify prevalence of AIP(mut) in a series of Turkish acromegalic patients.

PATIENTS AND METHODS

Direct sequencing of AIP gene was performed in 92 sporadic acromegalic patients.

RESULTS

One patient was found to have a new mutation in exon 6: g67.258,286 (G/A) heterozygote; (GGC/GAC; gly/asp). Apart from this new mutation, previously defined synonymous mutations in AIP gene were detected in seven patients (Exon 4; rs2276020; (GAC/GAT; asp/asp) and six patients were found to have five different intronic mutations in AIP gene which were not previously defined. The patient with pathogenic AIP(mut) presented at a young age and had an aggressive and treatment resistant tumour. The prevalence of AIP(mut) in Turkish patients was found to be 1 % in sporadic acromegaly in the present study. In addition, one synonymous mutation which was previously defined and six new intronic mutations have been described in Turkish acromegalic patients. All acromegalic patients with synonymous AIP(mut) presented with macroadenoma and majority of them had invasive tumour.

CONCLUSION

The prevalence of AIP(mut) in Turkish patients was found to be 1 % in sporadic acromegaly in the present study. This ratio increases when younger age groups are taken into account 6 % among patients <30 years of age at the time of diagnosis of acromegaly. The clinical features of acromegaly, such as having large and invasive tumours, may be affected by the presence of synonymous AIP(mut).

Laboratory investigation of acromegaly: is basal or random GH > 0.4 µg/L in the presence of normal serum IGF-1 an important result?

OBJECTIVE

To determine the frequency of indication of the GH suppression test and pituitary magnetic resonance imaging (MRI) in patients with clinical suspicion of acromegaly with GH concentrations > 0.4 µg/L despite normal serum IGF-1.

SUBJECTS AND METHODS

A total of 160 patients with clinical suspicion of acromegaly with normal IGF-1 were studied.

RESULTS

Basal GH > 0.4 µg/L was observed in 70/88 women (79.5%). Nadir GH > 0.4 µg/L was found in 21/70 women (30%) and these patients were submitted to MRI, which revealed a microadenoma in 2/21 women (9.5%). In these two women, IGF-1 continued to be normal in subsequent measurements and no clinical progression has been observed so far (time of follow-up until now 4 years). Basal GH > 0.4 µg/L was seen in 33/72 men (45.8%). Nadir GH was < 0.4 µg/L in all of them.

CONCLUSIONS

In patients with clinical suspicion of acromegaly, concern over GH concentration in the presence of normal IGF-1 results in the unwarranted complementary investigation in many cases, and even in possible equivocal diagnoses. It is only in exceptional cases that normal IGF-1 should not rule out acromegaly.

Effects of low dose versus high dose human growth hormone on body composition and lipids in adults with GH deficiency: a meta-analysis of placebo-controlled randomized trials

PURPOSE

Doses of growth hormone in adults with growth hormone deficiency are now lower than previously. However, it is not clear they are as effective as higher doses. The objective of this meta-analysis was to assess efficacy of low to moderate dose (LD) GH replacement on standard endpoints of GH compared to higher doses.

METHODS

A meta-analysis was carried out using PubMed, Cochrane and Embase databases from 1960 to 9/23/12. Three reviewers identified randomized double-blind, placebo-controlled trials of 6 months duration. Of 173 publications, 28 representing 22 trials (591 GH-treated patients and 562 placebo) were included. Data were independently extracted by three reviewers. Endpoints were analyzed if ≥4 studies per dose group reported baseline and 6 month data.

RESULTS

Mean lean body mass (LBM) increased by 2.61 kg in GH-treated subjects versus 0.04 in the placebo group (P < 0.0001). Fat mass (FM) was reduced by -2.19 kg versus 0.31 (GH vs. placebo) (P = 0.0002). Changes in LBM and FM were dose-related (P = 0.02 and 0.007, respectively), high dose (HD) being more effective than low dose (LBM P = 0.03 and FM P = 0.04). In contrast, treatment with GH reduced total cholesterol -0.38 mmol/L versus. 0.01 (placebo) (P < 0.0001), and low density lipoprotein cholesterol (LDL-C) -0.42 mmol/L versus -0.1 (P = 0.0009), but there were no differences between LD and HD GH.

CONCLUSIONS

LDs of hGH improve total- and LDL-C, and body composition. Higher doses are more effective on body composition, but not lipids.

Clinical assays for quantitation of insulin-like-growth-factor-1 (IGF1)

Insulin-like growth factor 1 (IGF1), a 70 amino acid peptide hormone is the principal mediator of effects of growth hormone (GH). Since GH secretion is pulsatile in nature and is affected by many factors including sleep, feeding and exercise it is not a reliable marker for diagnosis of GH related disorders. On the other hand, IGF1 levels does not undergo short-term fluctuations in the manner that GH does making it the preferred IGF1 biomarker for the diagnosis of growth related disorders. There are several immunoassays available for IGF1 determination. Since majority (>90%) of IGF1 circulates as a ternary complex bound to its principal carrier/binding protein, IGF binding protein 3 (IGFBP3) and acid labile subunit (ALS), the assay methodology used to quantitate IGF1 has to dissociate IGF1 from IGFBPs prior to quantitation. IGFBPs are known to be a source of interference in immunoassays and many techniques have been employed to circumvent this issue. Immunoassays rely on antibody specificity towards IGF1 and differential cross reactivity towards IGFBPs. Mass spectrometry (MS) has also been employed for quantitation of IGF1. Liquid chromatography tandem mass spectrometry (LC-MS/MS) assays for IGF1 rely on generating tryptic peptides followed by selective reaction monitoring (SRM) while LC high resolution accurate-mass mass spectrometry (LC-HRAMS) approaches for intact IGF1 rely on mass accuracy for reliable, robust and accurate quantitation. This review article will focus on the clinical assays available and the clinical utility of quantitative assessment of IGF1. IGF1 quantitation using diverse assay platforms including immunoassay, LC-MS/MS and LC-HRAMS are discussed in detail.

Growth hormone deficiency in treated acromegaly

Growth hormone deficiency (GHD) of the adult is characterized by reduced quality of life (QoL) and physical fitness, skeletal fragility, and increased weight and cardiovascular risk. Hypopituitarism may develop in patients after definitive treatment of acromegaly, but an exact prevalence of GHD in this population is still uncertain owing to limited awareness and the scarce and conflicting data available on this topic. Because acromegaly and GHD may yield adverse consequences on similar target systems, the final outcomes of some complications of acromegaly may be further affected by the occurrence of GHD. However, it is still largely unknown whether patients with post-acromegaly GHD may benefit from GH replacement. We review the diagnostic, clinical, and therapeutic aspects of GHD in adult patients treated for acromegaly.

Update on the evaluation and treatment of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a heritable bone fragility disorder that presents with a wide clinical phenotype spectrum: from perinatal lethality and severe deformities to very mild forms without fractures. Most cases of OI are due to autosomal dominant mutations of the type I collagen genes. A multidisciplinary approach with rehabilitation, orthopedic surgery, and consideration of medical therapy with bisphosphonates underpins current management. Greater understanding of the pathogenesis of OI may lead to novel, therapeutic approaches to help improve clinical symptoms of children with OI in the future.

Muscle-bone and fat-bone interactions in regulating bone mass: do PTH and PTHrP play any role?

Metabolic bone disease occurs when there is a net loss in bone density. Osteoporosis, the most common metabolic bone disease, is a devastating problem and an increasingly major public health issue. A substantial body of evidence in the elderly population indicates that a relationship exists between the components of body weight and various measures of bone/mass, density, and function. Both muscle and fat contribute to the body's total weight and the intimate associations of muscle, fat, and bone are known. But the close functional interactions between muscle and bone or fat and bone are largely unidentified and have drawn much attention in recent years. Each of these tissues not only responds to afferent signals from traditional hormone systems and the central nervous systems but also secretes factors with important endocrine functions. Studies suggest that during growth, development, and aging, the relationship of muscle and fat with the skeleton possibly governs bone homeostasis and turnover. A better understanding of the endocrine function and the cellular and molecular mechanisms and pathways linking muscle or adipose tissues with bone anabolism and catabolism is a new avenue for novel pathways for anabolic drug discovery. These in turn will likely lead to more rational therapy toward increasingly prevalent disorders like osteoporosis. In this review, some of the recent works on the interaction of bone with muscle and fat are highlighted, and in so doing the role of parathyroid hormone (PTH), and PTH-related peptide (PTHrP) is surveyed.

Screening for acromegaly in adult patients not reporting enlargement of the extremities, but with arterial hypertension associated with another comorbidity of the disease

OBJECTIVE

To determine the value of acromegaly screening in adult patients not reporting enlargement of the extremities, but who present arterial hypertension associated with at least one other comorbidity of the disease.

SUBJECTS AND METHODS

Patients seen by general practitioners at primary health care units were evaluated. Among the patients without extremity enlargement, those with recently diagnosed arterial hypertension associated with at least one other comorbidity were selected.

RESULTS

A total of 1,209 patients were submitted to laboratory investigation. Elevated IGF-1 was observed in 22 patients. Eighteen patients had adequate suppression of growth hormone (GH). No GH suppression was observed in four women with confirmed elevated IGF-1. In the latter, IGF-1 and nadir GH were only slightly elevated, magnetic resonance showed a normal pituitary, and chest and abdominal computed tomography revealed no tumor, and no intervention was performed.

CONCLUSION

In patients with arterial hypertension without known pituitary disease, acromegaly is unlikely in the absence of enlargement of the extremities.

Reappraisal of serum insulin-like growth factor-I (IGF-1) measurement in the detection of isolated and combined growth hormone deficiency (GHD) during the transition period

OBJECTIVE

To evaluate the accuracy of serum IGF-1 in the detection of isolated (IGHD) or combined growth hormone deficiency (CGHD) at the transition phase.

SUBJECTS AND METHODS

Forty nine patients with GHD during childhood [16 with IGHD (10 men) and 33 with CGHD (24 men); age 23.2 ± 3.5 yrs.] were submitted to an insulin tolerance test (ITT) with a GH peak < 5 µg/L used for the diagnosis of GHD at the transition phase. Pituitary function and IGF-1 measurements were evaluated in the basal sample of the ITT. Transition patients were reclassified as GH-sufficient (SGH; n = 12), IGHD (n = 7), or CGHD (n = 30).

RESULTS

Five (31%) patients with IGHD and 32 (97%) with CGHD at childhood persisted with GHD at retesting. One patient with IGHD was reclassified as CGHD, whereas 3 patients with CGHD were reclassified as IGHD. Mean GH peak was 0.2 ± 0.3 µg/L in the CGHD, 1.3 ± 1.5 µg/L in the IGHD, and 18.1 ± 13.1 µg/L in the SGH group. Serum IGF-1 level was significantly higher in the SGH (272 ± 107 ng/mL) compared to IGHD (100.2 ± 110) and CGHD (48.7 ± 32.8) (p < 0.01). All patients reclassified as CGHD, 86% reclassified as IGHD, and 8.3% reclassified as SGH had low IGF-1 level, resulting in 97.3% sensitivity and 91.6% specificity in the detection of GHD at the transition period; the cutoff value of 110 ng/mL showed 94.5% sensitivity and 100% specificity. Mean IGF-1 values did not differ in IGHD or CGHD associated with one, two, three, or four additional pituitary deficiencies.

CONCLUSION

IGF-1 measurement is accurate to replace ITT as initial diagnostic test for IGHD and CGHD detection at the transition phase.

A practical approach to acromegaly management in Latin America

INTRODUCTION

Evidence-based treatment guidelines have undoubtedly advanced medical practice and supported optimal management of acromegaly, but their application may be hampered by limited access to the latest treatment options.

METHODS

In this retrospective, narrative review, the authors revisited existing treatment guidelines for acromegaly in Latin America. These were considered in conjunction with published evidence chosen at the authors' discretion.

FINDINGS

In a socially and economically diverse region, such as Latin America, any regional practice guidelines need to appreciate that recommended treatment options, such as surgery by expert pituitary surgical teams and drug therapies, especially somatostatin analogs, are often not available due to limited resources. In these instances, physicians may be obliged to apply less effective therapeutic options.

CONCLUSIONS

The current article looks at the practical aspects of acromegaly management in Latin America and discusses this in the context of existing guidelines. Furthermore, we consider potential strategies to make better use of resources through combination and multimodal approaches to treatment.

A consensus on the diagnosis and treatment of acromegaly complications

In March 2011, the Acromegaly Consensus Group met to revise and update the guidelines on the diagnosis and treatment of acromegaly complications. The meeting was sponsored by the Pituitary Society and the European Neuroendocrinology Association and included experts skilled in the management of acromegaly. Complications considered included cardiovascular, endocrine and metabolic, sleep apnea, bone diseases, and mortality. Outcomes in selected, related clinical conditions were also considered, and included pregnancy, familial acromegaly and invasive macroadenomas. The need for a new disease staging model was considered, and design of such a tool was proposed.

Investigational therapies for acromegaly

INTRODUCTION

The treatment of acromegaly aims at normalizing growth hormone (GH) and insulin-like growth factor (IGF-I) levels and controlling tumor growth. The approaches to therapy are essentially three: surgery and pharmacotherapy, alone or in combination, and radiotherapy, generally used in more aggressive tumors.

AREAS COVERED

This review focuses on the novel drug formulations being developed for medical therapy of acromegaly. Even though many efficient treatments have been made available to manage acromegaly in the last two decades, a significant number of patients remain still uncontrolled. Medical therapy represents an important therapeutic option and can be used as the first-line treatment in many patients. However, roughly 25% of patients might be considered as poor responsive or resistant to conventional long-acting somatostatin analogs (SSA) treatment. Therefore, new longer-acting SSA, oral SSA formulations, new combined therapies with weekly doses of pegvisomant, combination therapy with pegvisomant (PEG) and cabergoline (CAB) or SSA and new approaches have been proposed. New molecules are currently under investigation in clinical trials, such as the SSA multi-receptor ligand, pasireotide, which represents a promising option therapy, especially in patients not adequately controlled with currently available SSA. Further, temozolomide has been suggested as an efficient drug for treating GH-aggressive pituitary tumors resistant to conventional therapy.

EXPERT OPINION

All these novel SSA formulations and new molecules implement the available options in therapies of acromegaly to improve disease control. However, further studies are needed to define the exact role of these newer agents. The predicting factors for response to these new therapies should also be determined.

Double, synchronous pituitary adenomas causing acromegaly and Cushing's disease. A case report and review of literature

Double pituitary adenomas are very rare and present up to 1 % of pituitary adenomas in unselected autopsy series and up to 2 % in large surgical series. We report a case of a 47-year-old man presented slight clinical features of acromegaly with 2 years duration. Endocrine evaluation confirmed active acromegaly and revealed adrenocorticotropin hormone-dependent hypercortisolemia. Preoperative magnetic resonance imaging of the pituitary demonstrated clearly separated double microadenomas with different intensity. The patient underwent transsphenoidal surgery and both tumors were completely removed and were fixed separately. The histological and ultrastructural examination confirmed coincidence of the double, clearly separated pituitary adenomas in one gland. Postoperative function of the hypothalamo-hypophyseal axis was normalized. We conclude from this case and a literature review that double endocrinologically active pituitary adenomas leading to acromegaly and Cushing's disease may occur. Additionally, a review of the literature regarding multiple pituitary adenomas has also been performed.

Glucocorticoids and the regulation of growth hormone secretion

Glucocorticoids modulate the secretion of growth hormone (GH) by various and competing effects on the hypothalamus and pituitary gland. The final effects of this modulation depend on hormone concentrations and the duration of exposure. The traditional hypothesis is that chronically raised levels of glucocorticoids suppress the secretion of GH. However, a functional impairment of the GH reserve might also be observed in patients with low levels of glucocorticoids, such as those with secondary hypoadrenalism, which is consistent with the model of biphasic dose-dependent effects of glucocorticoids on the somatotropic axis. This Review updates our current understanding of the mechanisms underlying the effects of glucocorticoids on the secretion of GH and the clinical implications of the dual action of glucocorticoids on the GH reserve in humans. This Review will also address the potential diagnostic and therapeutic implications of GH for patients with a deficiency or excess of glucocorticoids.

GH therapy in adult GH deficiency: a review of treatment schedules and the evidence for low starting doses

Recombinant human GH has been licensed for use in adult patients with GH deficiency (GHD) for over 15 years. Early weight- and surface area-based dosing regimens were effective but resulted in supraphysiological levels of IGF1 and increased incidence of side effects. Current practice has moved towards individualised regimens, starting with low GH doses and gradually titrating the dose according to the level of serum IGF1 to achieve an optimal dose. Here we present the evidence supporting the dosing recommendations of current guidelines and consider factors affecting dose responsiveness and parameters of treatment response. The published data discussed here lend support for the use of low GH dosing regimens in adult GHD. The range of doses defined as 'low dose' in the studies discussed here (∼1-4  mg/week) is in accordance with those recommended in current guidelines and encompasses the dose range recommended by product labels.

Growth hormone and the cardiovascular system

Growth hormone (GH) exerts its effects through insulin-like growth factor-1, and although ubiquitous in human tissues, it has a significant role in cardiovascular function. In recent years, there has been a great deal of interest in GH as an etiologic factor in many cardiovascular disease states. Acromegaly, a state of endogenous GH excess, results in myocardial hypertrophy and decreased cardiac performance with increased cardiovascular mortality. Additional insight into the role of excess GH on the cardiovascular system has been gained from data collected in athletes doping with GH. Likewise, GH deficiency is associated with increased mortality, possibly from the associated increase in atherosclerosis, lipid abnormalities, and endothelial dysfunction. However, further research is required to clarify the benefit of GH treatment in both deficient states and in heart failure patients.

Somatostatin analogs as a first-line treatment in acromegaly: when is it appropriate?

PURPOSE OF REVIEW

To discuss the role of medical therapy of acromegaly as a first-line treatment, focusing on recent data on the use of somatostatin analogs (SSAs), the first-choice pharmacotherapy for treating acromegaly.

RECENT FINDINGS

Despite pituitary surgery and radiotherapy, a significant number of patients with acromegaly needed adjuvant medical therapy, and primary medical therapy nowadays is increasingly considered. According to a recent consensus statement on the management of acromegaly, primary pharmacological therapy with SSAs may be indicated in patients who are otherwise poor surgical candidates or refuse surgery, and in those in whom there is a low probability of a surgical cure. The long-acting SSAs have been found to be effective in improving symptoms and signs of acromegaly in a high percentage of patients and induce normalization of growth hormone and insulin-like growth factor-I levels approximately in 60-80% of patients, respectively. Evidence has suggested that SSAs induce a clinically significant tumor shrinkage when given as first-line, when this reduction of tumor volume could be helpful in improving the outcome of subsequent surgery or improving the clinical syndrome in patients with unacceptable surgical risk, whereas the tumor shrinkage was seen less frequently when the drug was used after surgical resection and/or radiotherapy.

SUMMARY

Pharmacological management plays a pivotal role in the treatment of acromegaly, and first-line medical therapy with SSAs is being widely used in clinical practice, either prior to surgery or in patients who are otherwise poor surgical candidates and in those in whom there is a low probability of a surgical cure.

DG3173 (somatoprim), a unique somatostatin receptor subtypes 2-, 4- and 5-selective analogue, effectively reduces GH secretion in human GH-secreting pituitary adenomas even in Octreotide non-responsive tumours

OBJECTIVE

Somatostatin analogues (SSA) reduce autonomous GH secretion by activating somatostatin receptors (sst) 2 and 5 in 50-60% of acromegalic patients. However, by inhibiting insulin secretion these SSA reduce glucose tolerance. DG3173 is a novel SSA with additional binding to sst4 and low insulin-suppressing activity. We investigated the effect of DG3173, including its relation to specific tumour characteristics, on GH secretion in human somatotroph adenoma cell cultures (hSA) in comparison with Octreotide.

METHODS

Twenty-seven hSA were characterised immunohistochemically for their hormone- and sst-expression, granularity and pre-surgical therapy with SSA. GH was determined in supernatants of hSA treated with DG3173 or Octreotide in time- (n=6) and dose-response (n=21) experiments. A positive response was defined as GH suppression to below 80% of baseline.

RESULTS

In the dose-response experiments DG3173 suppressed GH secretion in more adenomas than Octreotide (10/21 vs 5/21), including 38% (6/16) of Octreotide non-responders. In responders the extent of GH suppression and IC(50) were comparable for both SSA. The response-rate of both SSA was higher in monohormonal vs bihormonal adenomas, yet GH declined similarly in both groups. Neither pre-surgical SSA (n=6) nor tumour morphology was related to the GH response. However, semi-quantitative analysis indicated a small but significant negative correlation between the GH response to Octreotide and the immunoreactivity scores of sst2 expression.

CONCLUSIONS

DG3173 equalled Octreotide in suppressing GH secretion in hSA. Since DG3173 suppressed GH in some Octreotide-non-responsive adenomas, its clinical effectiveness will be worth testing. Moreover, its reduced insulin-suppressive potency would make it a valuable alternative to Octreotide.

Diagnosing growth hormone deficiency in adults

Adult growth hormone (GH) deficiency is a recognised syndrome associated with adverse phenotypic, metabolic, and quality-of-life features which improve in many patients when GH is substituted. The appropriate selection of patients at risk of growth hormone deficiency (GHD) is the crucial first step in arriving at a correct diagnosis. Although multiple diagnostic modalities are available including a 24-hour serum GH profile, stimulated GH levels, and insulin-like growth factor-1 (IGF-1) levels, the use of dynamic tests for GH reserves is required in most cases. This paper discusses the utility and drawbacks of the various testing modalities with reference to international guidelines. Regardless of the test chosen, clinical pitfalls including age and obesity must be taken into account. In addition, there is considerable analytical variation in the biochemical measurements of GH and IGF-1 which must be considered before making a diagnosis of GHD in adulthood.

Comparison of primary octreotide-lar and surgical treatment in newly diagnosed patients with acromegaly

OBJECTIVE

The primary aim of the study was to compare the efficacy of Oct-LAR and surgery in terms of controlling IGF-1 and GH levels and tumour volumes. The second aim was to compare two primary treatment modalities in terms of side effects such as pituitary insufficiency, cholelithiasis, metabolic parameters and the effect on quality of life (QoL).

DESIGN

The study was a randomized, prospective study.

PATIENTS

The 22 patients were consecutively randomized to Oct-LAR and surgical treatment groups.

RESULTS

Baseline serum IGF-1 level, tumour volume and GH levels were comparable in the Oct-LAR and surgery groups. No significant differences were detected between the Oct-LAR and the surgery groups in terms of IGF-1 and GH levels at the 3rd and 6th months, but at 12th month, preglucose GH was found to be lower in the surgical treatment group. IGF-1 control and complete biochemical response rates were found to be 27% and 64%, in the Oct-LAR and surgical treatment groups, respectively. The mean percentage of tumour volume reduction was found to be 26%, 30% and 31% in the Oct-LAR group vs 64%, 74% and 79% in the surgery group at the 3rd, 6th and 12th months, respectively.

CONCLUSION

Primary surgical treatment seems to be slightly more effective than Oct-LAR in terms of biochemical response and IGF-1 control, besides tumour volume reduction, in patients with acromegaly with noninvasive tumours. Oct-LAR is associated with more side effects such as cholelithiasis and glucose metabolism disorders and is more expensive.

Pituitary autoimmunity is associated with hypopituitarism in patients with primary empty sella

OBJECTIVE

Some evidence suggests that late stage autoimmune hypophysitis (AH) may result in empty sella (ES). Aim of the study was to assess the prevalence of serum pituitary antibodies (PitAb) and their correlation with pituitary function in patients with ES.

DESIGN

In this casecontrol study 85 patients with primary ES, 16 patients with ES secondary to head trauma, 214 healthy controls, and 16 AH were enrolled in a tertiary referral center.

METHODS

PitAb were assessed in all cases and controls. Endocrine function was assessed by basal hormone measurement and dynamic testing in all ES cases.

RESULTS

PitAb prevalence was higher in primary ES (6%) than in healthy subjects (0.5% p=0.003) and lower than in AH patients (50%, p<0.0001). PitAb were not found in patients with secondary ES. Hypopituitarism was found in 49% of primary ES and in 62% of secondary ES (p=0.34). A positive correlation between the presence of PitAb and hypopituitarism was found in primary ES (p=0.02).

CONCLUSIONS

The significant association between pituitary autoimmunity and hypopituitarism suggests that ES, in selected cases, could be the final result of AH.