Complications of acromegaly: cardiovascular, respiratory and metabolic comorbidities

Preclinical markers of atherosclerosis in acromegaly: a systematic review and meta-analysis

OBJECTIVE

Multiple studies investigated preclinical markers of peripheral vascular damage in acromegaly (ACRO) reporting discordant results. The aim of this study was to run a meta-analysis to examine whether intima media thickness (IMT), flow mediated dilation (FMD) and arterial pulse wave velocity (PWV) are affected in acromegalic patients and to assess the impact of effective treatment of growth hormone excess on these outcomes.

STUDY SELECTION

Twenty-seven studies comparing ACRO vs control (CON) populations and active (ACT) vs inactive (INACT) ACRO were included in the meta-analysis.

DATA SYNTHESIS

ACRO compared to CON have higher IMT (ES = 0.83, 95% C.I. 0.35-1.30), p = 0.001, impaired FMD (ES = - 1.59, 95% C.I. - 2.33 to - 0.85, p < 0.0001) and higher PWV (ES = 0.76 95% C.I. 0.37-1.16, p = 0.0001). When patients with ACT vs INACT disease were considered IMT was higher (ES = 0.43, 95% C.I. 0.02-0.84, p = 0.041) and FMD was impaired (ES = - 0.66, 95% C.I. - 1.28 to 0.04, p = 0.038) in ACT patients. Meta-regression analysis of studies comparing IMT in ACT vs INACT acromegalic patients showed a significant and inverse association between the effect size and the percent of hypertensive (p = 0.025) and diabetic (p = 0.041) patients.

CONCLUSIONS

IMT, FMD and arterial stiffness are impaired in acromegaly showing that these patients may be at increased risk of atherosclerosis. In patients with active disease these preclinical markers of atherosclerosis are worse compared to patients with inactive disease but the role of diabetes and hypertension is prevailing on growth hormone excess.

Prevalence and risk factors of sleep breathing disorders in patients with acromegaly from Moscow region

Aim. Assessment of prevalence and risk factors of sleep breathing disorders in patients with acromegaly from Moscow region. Materials and methods. Cardiorespiratory monitoring was executed to 55 patients with acromegaly (18 men and 37 women): 27 patients with de novo disease, 28 patients on treatment of acromegaly (including 18 patietns with uncontrolled and 10 - with controlled acromegaly). All subgroups did not differ on sex, BMI and age. Also 24-hour monitoring of arterial blood pressure was carried out in 39 patients (12 men and 27 women, 14 patients with de novo acromegaly, 15 and 10 patients with uncontrolled and controlled acromegaly, respectively). Results and discussion. The high prevalence of sleep breathing disorders (SBD) was revealed in patients with acromegaly from Moscow Region. SBD was found in 92.6%, 83.5% and 70.0% patients with newly diagnosed, uncontrolled and controlled acromegaly, respectively. The majority of patients had severe/moderate SBD in all subgroups (78.8%, 72.2% and 60.0%, respectively). In patients with newly diagnosed and uncontrolled acromegaly index of apnea-hypopnea (31 and 38.5 respectively), number of apnoe episodes (76 and 72) and saturation level (93% and 93.5%) did not differ significantly while these parameters were better in patients with a controlled acromegaly (apnea-hypopnea index 20, apnea episodes 45.5 and saturation level 95%). The peak of desaturation was subphysiological in 91.7%, 86.7% and 77.8% of patients with newly diagnosed, uncontrolled and controlled acromegaly, respectively. Severity of SBD did not depend on GH and IGF-1 levels as well as acromegaly duration. Such all-population risk factors of SBD as BMI and age were valuable for patients with acromegaly, however gender did not matter. SBD were associated with lack of physiological decrease of systolic and diastolic night BP. Conclusion. Acromegaly per se is a strong risk factor of sleep breathing disorders. The high prevalence of sleep breathing disorders in patients with acromegaly even after achievement of control over a disease emphasized need of specialized treatment of these violations.

A Consensus Statement on acromegaly therapeutic outcomes

The 11th Acromegaly Consensus Conference in April 2017 was convened to update recommendations on therapeutic outcomes for patients with acromegaly. Consensus guidelines on the medical management of acromegaly were last published in 2014; since then, new pharmacological agents have been developed and new approaches to treatment sequencing have been considered. Thirty-seven experts in the management of patients with acromegaly reviewed the current literature and assessed changes in drug approvals, clinical practice standards and clinical opinion. They considered current treatment outcome goals with a focus on the impact of current and emerging somatostatin receptor ligands, growth hormone receptor antagonists and dopamine agonists on biochemical, clinical, tumour mass and surgical outcomes. The participants discussed factors that would determine pharmacological choices as well as the proposed place of each agent in the guidelines. We present consensus recommendations highlighting how acromegaly management could be optimized in clinical practice.

Cost-effectiveness of somatostatin analogues in the treatment of acromegaly

INTRODUCTION

Somatostatin analogues (SSAs) are the largest contributor to the direct medical cost of acromegaly management worldwide. The aim of this review was to identify and report available evidence on the cost-effectiveness of SSAs in the treatment of acromegaly.

AREAS COVERED

A literature search on relevant papers published up to April 2018 was performed. A total of 22 eligible studies (10 full-text articles and 12 conference abstracts) conducted in 14 countries were included in the analysis. In majority of studies, modelling technique was the principal research method.

EXPERT COMMENTARY

The results of cost-effectiveness analyses: 1) support published recommendations where SSAs are indicated as first-line medical treatment for patients with persistent disease after surgery or who are not eligible for surgery; 2) suggest that preoperative medical therapy with SSAs may be highly cost-effective in acromegalic patients with macroadenoma, in centres without optimal surgical results 3) indicate that in some countries pasireotide and pegvisomant appeared to be cost-effective or even dominant strategies in comparison to first-generation SSAs. The main limitation of economic evaluations was the lack of high-quality studies designed to directly compare various treatment strategies in acromegaly.

Shorter telomeres associated with high doses of glucocorticoids: the link to increased mortality?

OBJECTIVE

Patients with non-functioning pituitary adenomas exhibit high morbidity and mortality rates. Growth hormone deficiency and high doses of glucocorticoid substitution therapy have been identified as corresponding risk factors. Interestingly, high levels of endogenous cortisol in, e.g., patients with post-traumatic stress disorder or patients with Cushing's disease have been linked to shorter telomere length. Telomeres are noncoding DNA regions located at the end of chromosomes consisting of repetitive DNA sequences which shorten with ageing and hereby determine cell survival. Therefore, telomere length can serve as a predictor for the onset of disease and mortality in some endocrine disorders (e.g., Cushing's disease).

DESIGN/METHODS

We examine telomere length from blood in patients (n = 115) with non-functioning pituitary adenomas (NFPA) in a cross-sectional case control (n = 106, age-, gender- matched) study using qPCR. Linear regression models were used to identify independent predictors of telomere length.

RESULTS

We show that patients with NFPA exhibited shorter telomeres than controls. No significant association of indices of growth hormone deficiency (IGF-1-level-SDS, years of unsubstituted growth hormone deficiency etc.) with telomere length was detected. Interestingly, linear regression analysis showed that hydrocortisone replacement dosage in patients with adrenal insufficiency (n = 52) was a significant predictor for shorter telomere length (β = 0.377; p = 0.018) independent of potential confounders. Median split analysis revealed that higher hydrocortisone intake (> 20 mg) was associated with significantly shorter telomeres.

CONCLUSION

These observations strengthen the importance of adjusted glucocorticoid treatment in NFPA patients with respect to morbidity and mortality rates.

CARDIOVASCULAR COMPLICATIONS OF ACROMEGALY

Acromegaly is associated with increased mortality and decreased life expectancy. Cardiovascular disease is the principal cause of premature mortality in patients with acromegaly, accounting for about 60% of deaths. GH and/or IGF-I exert direct cardiac effects: enhance cardiac contractility, stimulate cardiomyocyte growth, influence calcium influx in cardiomyocytes. Cardiac remodelling is influenced by hypertension and insulin resistance. Among cardiovascular risk factors arterial hypertension, reported in 35% of patients with acromegaly, ranks among most important negative prognostic factors for mortality. Hypertension plays significant role in the development of cardiac hypertrophy, especially in older acromegalic patients and diastolic blood pressure is best predictive factor for cardiac hypertrophy. Therefore, early and aggressive hypertension treatment is essential for prognosis in acromegaly. Other important risk factors are: valvular defects, arrhythmias, endothelial dysfunction, heart failure, lipid abnormalities and coronary artery disease. Numerous studies suggest that patients with acromegaly are under threat of arrhythmias, especially those with structural heart abnormalities. Congestive heart failure as end-stage acromegalic cardiomyopathy occurs usually in older patients, with long-term uncontrolled disease and other cardiovascular and metabolic complications. Relation between acromegaly and coronary artery disease is controversial as it seems to be connected rather with classical cardiovascular risk factors than GH and IGF-1 overexpresion.

Top 100 Most-Cited Articles on Pituitary Adenoma: A Bibliometric Analysis

BACKGROUND

Many articles have been published on pituitary adenomas. Bibliometric analyses are helpful for determining the most impactful studies within a field.

OBJECTIVE

To identify the top 100 most-cited articles on pituitary adenomas using the bibliometric analysis method.

METHODS

We searched the Thomson Reuters Web of Science on March 31, 2018. Articles were listed in descending order by the total citation (TC) number, and the most-cited articles on pituitary adenomas were identified and analyzed.

RESULTS

The most-cited articles were published between 1970 and 2014, with 1999 as the most prolific year. Growth hormone-secreting pituitary adenoma was the most commonly studied tumor subtype (43%), and in clinical studies, treatment options and follow-up were the most important research focuses (62%). The average number of TCs was 326, and the average number of annual citations (ACs) was 17. More review articles were published in the last decade, and the average number of ACs was higher for this decade than for previous decades. Twenty-one articles were recognized as citation Ccassics, with a TC number >400. Twenty-five journals published the top 100 works; Journal of Clinical Endocrinology and Metabolism published the most articles (25%). The most articles (43%) were published in the United States. S. Melmed wrote the greatest number of publications (14%). Departments of medicine (32%) and endocrinology (32%) contributed to the largest number of articles.

CONCLUSIONS

This study identified the research focuses and trends regarding pituitary adenoma and provides key references for investigators in guiding future pituitary adenoma research.

Association between radiological parameters and clinical and molecular characteristics in human somatotropinomas

Acromegaly is a rare but severe disease, originated in 95% of cases by a growth hormone-secreting adenoma (somatotropinoma) in the pituitary. Magnetic resonance imaging (MRI) is a non-invasive technique used for the diagnosis and prognosis of pituitary tumours. The aim of this study was to determine whether the use of T2-weighted signal intensity at MRI could help to improve the characterisation of somatotropinomas, by analysing its relationship with clinical/molecular features. An observational study was implemented in a cohort of 22 patients (mean age = 42.1 ± 17.2 years; 59% women; 95% size>10 mm). Suprasellar-extended somatotropinomas presented larger diameters vs. non-extended tumours. T2-imaging revealed that 59% of tumours were hyperintense and 41% isointense adenomas, wherein hyperintense were more invasive (according to Knosp-score) than isointense adenomas. A higher proportion of hyperintense somatotropinomas presented extrasellar-growth, suprasellar-growth and invasion of the cavernous sinus compared to isointense adenomas. Interestingly, somatostatin receptor-3 and dopamine receptor-5 (DRD5) expression levels were associated with extrasellar and/or suprasellar extension. Additionally, DRD5 was also higher in hyperintense adenomas and its expression was directly correlated with Knosp-score and with tumour diameter. Hence, T2-weighted MRI on somatotropinomas represents a potential tool to refine their diagnosis and prognosis, and could support the election of preoperative treatment, when required.

Efficacy of combined treatment with pasireotide, pegvisomant and cabergoline in an acromegalic patient resistant to other treatments: a case report

BACKGROUND

The approach to acromegalic patients with persistent acromegaly after surgery and inadequate response to first-generation somatostatin receptor ligands (SRLs) should be strictly tailored. Current options include new pituitary surgery and/or radiosurgery, or alternative medical treatment with SRLs high dose regimens, pegvisomant (PEG) as monotherapy, or combined therapy with the addition of PEG or cabergoline to SRLs. A new pharmacological approach includes pasireotide, a second-generation SRL approved for patients who do not adequately respond to surgery and/or for whom surgery is not an option. No reports on efficacy and safety of combined therapy with pasireotide and pegvisomant (PEG) in acromegaly are available.

CASE PRESENTATION

Here we report the case of a 41-year-old acromegalic man with a mixed GH/PRL pituitary adenoma post-surgical resistant to first-generation SRLs both alone and in combination with cabergoline and PEG who achieved biochemical and tumor control with the combined triple treatment with pasireotide, PEG and cabergoline without adverse events and with a good compliance to treatment.

CONCLUSIONS

Twelve months of therapy with pasireotide, PEG and cabergoline proved to be safe and effective in this particular patient and the clinical improvement of disease resulted in an improved compliance to treatment.

Diabetes Secondary to Acromegaly: Physiopathology, Clinical Features and Effects of Treatment

Acromegaly is a rare disease due to chronic GH excess and to the consequent increase in IGF-1 levels. Both GH and IGF-1 play a role in intermediate metabolism affecting glucose homeostasis. Indeed, chronic GH excess impairs insulin sensitivity, increases gluconeogenesis, reduces the glucose uptake in adipose tissue and muscle and alters pancreatic β cells function. As a consequence, glucose metabolism alterations are a very frequent complication in acromegaly patients, further contributing to the increased cardiovascular risk and mortality. Treatment modalities of acromegaly differently impact on glucose tolerance. Successful surgical treatment of acromegaly ameliorates glucose metabolism abnormalities. Drugs used to treat acromegaly patients may per se affect glucose homeostasis, therefore influencing patients' management. Indeed pegvisomant has been shown to positively impact on glucose metabolism, while somatostatin analogs, especially pasireotide, can cause hyperglycaemia. On the other hand, robust data on the effect of dopamine agonists on glycaemic profile are still lacking. This review summarizes the available data on diabetes mellitus in acromegaly patients, with a focus on the potential effects of the medical treatment of the disease on glucose homeostasis, providing an overview of the current state of the art.

Smooth Muscle-Specific BCL6+/- Knockout Abrogates Sex Bias in Chronic Hypoxia-Induced Pulmonary Arterial Hypertension in Mice

The "estrogen paradox" in pulmonary arterial hypertension (PAH) refers to observations that while there is a higher incidence of idiopathic PAH in women, rodent models of PAH show male dominance and estrogens are protective. To explain these differences, we previously proposed the neuroendocrine-STAT5-BCL6 hypothesis anchored in the sex-biased and species-specific patterns of growth hormone (GH) secretion by the pituitary, the targeting of the hypothalamus by estrogens to feminize GH secretion patterns, and the role of the transcription factors STAT5a/b and BCL6 as downstream mediators of this patterned GH-driven sex bias. As a test of this hypothesis, we previously reported that vascular smooth muscle cell- (SMC-) specific deletion of the STAT5a/b locus abrogated the male-dominant sex bias in the chronic hypoxia model of PAH in mice. In the present study, we confirmed reduced BCL6 expression in pulmonary arterial (PA) segments in both male and female SMC:STAT5a/b-/- mice. In order to test the proposed contribution of BCL6 to sex bias in PAH, we developed mice with SMC-specific deletion of BCL6+/- by crossing SM22α-Cre mice with BCL6-floxed mice and investigated sex bias in these mutant mice in the chronic hypoxia model of PAH. We observed that the male-bias observed in wild-type- (wt-) SM22α-Cre-positive mice was abrogated in the SMC:BCL6+/- knockouts-both males and females showed equivalent enhancement of indices of PAH. The new data confirm BCL6 as a contributor to the sex-bias phenotype observed in hypoxic PAH in mice and support the neuroendocrine-STAT5-BCL6 hypothesis of sex bias in this experimental model of vascular disease.

Association between dopamine and somatostatin receptor expression and pharmacological response to somatostatin analogues in acromegaly

Acromegaly is a hormonal disorder resulting from excessive growth hormone (GH) secretion frequently produced by pituitary adenomas and consequent increase in insulin‐like growth factor 1 (IGF‐I). Elevated GH and IGF‐I levels result in a wide range of somatic, cardiovascular, endocrine, metabolic and gastrointestinal morbidities. Somatostatin analogues (SSAs) form the basis of medical therapy for acromegaly and are currently used as first‐line treatment or as second‐line therapy in patients undergoing unsuccessful surgery. However, a considerable percentage of patients do not respond to SSAs treatment. Somatostatin receptors (SSTR1‐5) and dopamine receptors (DRD1‐5) subtypes play critical roles in the regulation of hormone secretion. These receptors are considered important pharmacological targets to inhibit hormone oversecretion. It has been proposed that decreased expression of SSTRs may be associated with poor response to SSAs. Here, we systematically examine SSTRs and DRDs expression in human somatotroph adenomas by quantitative PCR. We observed an association between the response to SSAs treatment and DRD4, DRD5, SSTR1 and SSTR2 expression. We also examined SSTR expression by immunohistochemistry and found that the immunohistochemical detection of SSTR2 in particular might be a good predictor of response to SSAs.

A Functional Interplay between IGF-1 and Adiponectin

A functional relationship is suggested between two well-known protein hormones, insulin-like growth factor 1 (IGF-1) and adiponectin. In the last two decades in fact, different experimental evidence has indicated a non-random link between them. Here, we describe briefly the IGF-1 and adiponectin systems, and we then focus on their putative interplay in relation to several pathological conditions, including obesity, diabetes, insulin resistance, cardiovascular disease, and cancer. Although the existing studies are hardly comparable, they definitely indicate a functional connection between these two protein hormones. In conclusion, the current knowledge strongly encourages further research into the common, as well as novel, mechanisms through which IGF-1 and adiponectin exert their concerted action.

Acromegaly at diagnosis in 3173 patients from the Liège Acromegaly Survey (LAS) Database

Acromegaly is a rare disorder caused by chronic growth hormone (GH) hypersecretion. While diagnostic and therapeutic methods have advanced, little information exists on trends in acromegaly characteristics over time. The Liège Acromegaly Survey (LAS) Database, a relational database, is designed to assess the profile of acromegaly patients at diagnosis and during long-term follow-up at multiple treatment centers. The following results were obtained at diagnosis. The study population consisted of 3173 acromegaly patients from ten countries; 54.5% were female. Males were significantly younger at diagnosis than females (43.5 vs 46.4 years; P < 0.001). The median delay from first symptoms to diagnosis was 2 years longer in females (P = 0.015). Ages at diagnosis and first symptoms increased significantly over time (P < 0.001). Tumors were larger in males than females (P < 0.001); tumor size and invasion were inversely related to patient age (P < 0.001). Random GH at diagnosis correlated with nadir GH levels during OGTT (P < 0.001). GH was inversely related to age in both sexes (P < 0.001). Diabetes mellitus was present in 27.5%, hypertension in 28.8%, sleep apnea syndrome in 25.5% and cardiac hypertrophy in 15.5%. Serious cardiovascular outcomes like stroke, heart failure and myocardial infarction were present in <5% at diagnosis. Erythrocyte levels were increased and correlated with IGF-1 values. Thyroid nodules were frequent (34.0%); 820 patients had colonoscopy at diagnosis and 13% had polyps. Osteoporosis was present at diagnosis in 12.3% and 0.6-4.4% had experienced a fracture. In conclusion, this study of >3100 patients is the largest international acromegaly database and shows clinically relevant trends in the characteristics of acromegaly at diagnosis.