Improvement of endothelial dysfunction in acromegaly after transsphenoidal surgery

Capillary microarchitectural changes are independent of disease activity in acromegaly

OBJECTIVE

Although atherosclerosis-related macrovascular complications are well known in acromegaly, studies on endothelial function and arteriolar level are contradictory. In order to test the hypothesis, microvascular changes associated with macrovascular changes in acromegaly, we aimed to evaluate microvascular changes in nailfold capillaries and carotid intima-media thickness (CIMT) in patients with acromegaly.

DESIGN

In this cross-sectional observation study, of total 70 patients with acromegaly [ten (14.3 %) were active acromegaly (AA), 60 (85.7 %) were controlled acromegaly (CA)] and 74 healthy controls were enrolled. Microvascular structure was evaluated using the nailfold video capillaroscopy, and CIMT was measured using ultrasonography.

RESULTS

The median number of capillaries was less [10 no./mm (min-max: 5-16) vs. 11 no./mm (min-max: 9-15); p = 0.001] in the acromegaly group than in the controls. Capillaries below 6-8 per/mm was more common in the acromegaly patients [six (8.6 %) vs. one (1.4 %); p = 0.046]. All capillaroscopic parameters were similar among the patients with CA or AA. CIMT levels were higher in the acromegaly group than in the control group [0.60 mm (0.43-0.86) vs. 0.38 mm (0.27-0.59); p < 0.001], and AA patients had higher CIMT than CA patients (p = 0.037). None of the clinical or laboratory parameters including growth hormone and IGF-1 were related to capillaroscopic parameters or CIMT.

CONCLUSION

Decreased capillary number was the major capillaroscopic finding in acromegaly and there was no significant difference between active and controlled cases, but CIMT was found to be higher in the active group. Increased CIMT levels in acromegaly were not associated with capillary changes. Large-scale, prospective studies are needed to make a definite conclusion about the effect of the disease activity on nailfold capillaries and its association with macrovascular changes.

Advances in Research on the Cardiovascular Complications of Acromegaly

Cardiovascular-related complications are one of the most common complications in patients with acromegaly, and can lead to an increased risk of death. Hypertension and cardiomyopathy are the main cardiovascular complications. The characteristics of acromegalic cardiomyopathy are concentric biventricular hypertrophy and diastolic dysfunction. In addition, arrhythmia and heart valve disease are common cardiac complications in acromegaly. Although the underlying pathophysiology has not been fully elucidated, the spontaneous overproduction of GH and IGF-1, increasing age, prolonged duration of disease and the coexistence of other cardiovascular risk factors are crucial to cardiac complications in patients with acromegaly. Early diagnosis and appropriate treatment of acromegaly might be beneficial for the prevention of cardiomyopathy and premature death.

The association between treatment and systemic inflammation in acromegaly

OBJECTIVE

Acromegaly is characterized by an excess of growth hormone (GH) and insulin like growth-factor 1 (IGF1), and it is strongly associated with cardiovascular diseases (CVD). Both acute and long-lasting pro-inflammatory effects have been attributed to IGF1. Previous results suggest the presence of systemic inflammation in treated patients. Here we assessed the association between treatment of acromegaly, systemic inflammation and vascular function.

DESIGN

Ex vivo cytokine production and circulating inflammatory markers were assessed in peripheral blood from treated and untreated acromegaly patients (N = 120), and compared them with healthy controls. A more comprehensive prospective inflammatory and vascular assessment was conducted in a subgroup of six treatment-naive patients with follow-up during treatment.

RESULTS

Circulating concentrations of VCAM1, E-selectin and MMP2 were higher in patients with uncontrolled disease, whereas the concentrations of IL18 were lower. In stimulated whole blood, cytokine production was skewed towards a more pro-inflammatory profile in patients, especially those with untreated disease. Prospective vascular measurements in untreated patients showed improvement of endothelial function during treatment.

CONCLUSIONS

Acromegaly patients are characterized by a pro-inflammatory phenotype, most pronounced in those with uncontrolled disease. Treatment only partially reverses this pro-inflammatory bias. These findings suggest that systemic inflammation could contribute to the increased risk of CVD in acromegaly patients.

HOMA-IR in acromegaly: a systematic review and meta-analysis

PURPOSE

This review is aimed at examining whether the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) is higher in Caucasian, adult, treatment-naïve patients with acromegaly (ACRO) than in the reference population independently of diabetes presence and to evaluate the impact of treatment [surgery and somatostatin analogues (SSAs)] on its assessment.

METHODS

We systematically reviewed in PubMed and Web of Science from July 1985 to December 2019, registered with the code number CRD42020148737. The inclusion criteria comprised studies conducted in Caucasian adult treatment-naïve patients with active ACRO in whom HOMA-IR or basal insulin and glucose were reported. Three reviewers screened eligible publications, extracted the outcomes, and assessed the risk of biases.

RESULTS

Of 118 originally selected studies, 15 met the inclusion criteria. HOMA-IR was higher in ACRO than the reference population, with mean difference and (95% confidence intervals) of 2.04 (0.65-3.44), even in ACRO patients without diabetes, 1.89 (1.06-2.73). HOMA-IR significantly decreased after treatment with either surgery or SSAs - 2.53 (- 3.24- - 1.81) and - 2.30 (- 3.05- - 1.56); respectively. However, the reduction of HOMA-IR due to SSAs did not improve basal glucose.

CONCLUSION

HOMA-IR in treatment-naïve ACRO patients is higher than in the reference population, even in patients without diabetes. This finding, confirms that insulin resistance is an early event in ACRO. Our results also suggest that HOMA-IR is not an adequate tool for assessing insulin resistance in those patients treated with SSAs.

Endothelial dysfunction in patients with acromegaly and It's association with Endocan

OBJECTIVE

This study aims to assess endocan levels in patients with acromegaly who have active disease or disease in remission and to investigate a relation between endocan levels and endothelial dysfunction in these patients.

DESIGN

The study is a case-control study. Study was conducted at Istanbul Medeniyet University Goztepe Training and Research Hospital between 2013 and 2019. Patients who were older than 18 years with acromegaly diagnosis were recruited if they agreed to participate. Patients with uncontrolled diabetes (DM), hypertension (HT), hyperlipidemia, decompensated heart failure, immune or infectious diseases, moderate-severe valve disease and stage 3 or more advanced chronic kidney disease were excluded. There were 30 healthy control subjects who agreed to participate to the study. Patients with acromegaly were divided into two groups as: disease active patients and patients in remission. Serum endocan levels were measured with enzyme linked immunosorbent assay (ELISA) method endothelial function was assessed with flow mediated dilatation (FMD).

RESULTS

There were 85 patients included to the study. Twenty-three patients had active disease, 31 were in remission and 31 were healthy controls. FMD was higher in controls compared to patients in active disease and patients in remission (p < 0.001). There was no difference between patients with active disease for FMD and patients in remission (p = 0.088). There was statistically significant correlation between FMD and endocan and insulin like growth hormone-1 (IGF-1) levels of patients with acromegaly. As FMD increased endocan and IGF-1 decreased. A moderate negative relation between FMD and endocan was identified (p < 0.001, r:-0.409) as well as FMD and IGF-1 levels (p:0.011, r:-0.377). Along with endocan and IGF-1, DM, HT, sex, body mass index, age and uric acid were associated with changes in FMD.

CONCLUSIONS

Endocan levels and endothelial function measured with FMD have an inverse relationship. Endocan may prove to be a marker for endothelial dysfunction in acromegaly.

Growth hormone control and cardiovascular function in patients with acromegaly

BACKGROUND

Acromegaly is associated with cardiovascular alterations. Up to 50% acromegalic patients suffered from treatment failure after multiple modalities. We investigated correlation between cardiovascular function and control of growth hormone (GH) in acromegalic patients following transsphenoidal adenomectomy (TSA).

METHODS

We recruited acromegalic patients who had undergone TSA between 2006 and 2014 in this cross-sectional study. Patients were assigned to group 1, controlled acromegaly (GH <1.0 ng/mL and normalized insulin-like growth factor-1 [IGF-1]); group 2, partially controlled acromegaly (either GH >1.0 ng/mL or non-normalized IGF-1); or group 3, uncontrolled acromegaly (GH >1.0 ng/mL and non-normalized IGF-1). Echocardiography evaluated the left ventricular mass index, left ventricular ejection fraction, and the early transmitral filling velocity (E)-to-late transmitral filling velocity (A) and the E-to-the early diastolic mitral annular velocity (E') ratios. Carotid tonometry evaluated the intima-media thickness of the carotid artery, carotid-femoral pulse wave velocity, augmentation index, aortic characteristic impedance (Zc), and pulse pressure amplification.

RESULTS

Thirty-three patients participated in this study. Fourteen of the 33 patients were males (42%). Mean age at diagnosis was 50.33 years (SD 18.45). Compared to patients in group 1, patients in group 3 had younger age and shorter years after operation, without statistical significance. Cumulative GH levels were progressively higher from group 1 to group 3, without statistical significance. The groups did not differ with respect to cardiovascular structure and function evaluated by echocardiography and carotid tonometry. Only Zc value had a difference that was of borderline significance (group 1: 109.13 ± 32.99; group 2: 129.30 ± 32.27; group 3: 159.56 ± 77.4 dynes × s/cm5; ANOVA p = 0.088; p = 0.086 for group 1 vs group 3).

CONCLUSION

In the patients with acromegaly who had undergone TSA, cardiac structure and vascular stiffness did not differ among the groups with different levels of GH control.

Acromegaly, inflammation and cardiovascular disease: a review

Acromegaly is characterized by Growth Hormone (GH) and Insulin-like Growth Factor 1 (IGF-1) excess. Uncontrolled acromegaly is associated with a strongly increased risk of cardiovascular disease (CVD), and numerous cardiovascular risk factors remain present after remission. GH and IGF-1 have numerous effects on the immune and cardiovascular system. Since endothelial damage and systemic inflammation are strongly linked to the development of CVD, and have been suggested to be present in both controlled as uncontrolled acromegaly, they may explain the presence of both micro- and macrovascular dysfunction in these patients. In addition, these changes seem to be only partially reversible after remission, as illustrated by the often reported presence of endothelial dysfunction and microvascular damage in controlled acromegaly. Previous studies suggest that insulin resistance, oxidative stress, and endothelial dysfunction are involved in the development of CVD in acromegaly. Not surprisingly, these processes are associated with systemic inflammation and respond to GH/IGF-1 normalizing treatment.

Role of growth hormone signaling pathways in the development of atherosclerosis

OBJECTIVE

The direct actions of growth hormone (GH) in the development of atherosclerosis are unclear. The goal of this study was to characterize GH-induced changes in expression of signaling pathway elements and other proteins that may be related to atherosclerosis.

METHODS

Human umbilical vein endothelial cells (HUVEC) and THP-1, a human acute monocytic leukemia cell line, were stimulated by exposure to 10^-9 M or 10^-8 M human GH with or without pretreatment with a mitogen-activated protein kinase kinase (MEK) 1 inhibitor. Levels of transcripts encoding vascular cell adhesion molecule (VCAM) -1, E-selectin, monocyte chemotactic protein (MCP-1), interleukin (IL) -6, and IL-8 were investigated by reverse transcription (RT) -PCR. For the quantitative adhesion assay, THP-1 cells or human primary monocytes were fluorescently labeled with 3'-O-acetyl-2',7'-bis(carboxyethyl) -4 diacetoxymethyl ester (BCECF/AM). HUVEC treated with human GH were co-incubated with BCECF-labeled THP-1 cells. One hour later, the number of BCECF-labeled THP-1 cells was assessed. An equivalent experiment was performed using BCECF-labeled primary monocytes, and the number of monocytes adhering to HUVEC was counted.

RESULTS

Treatment with hGH increased the levels of E-selectin- and VCAM-1-encoding mRNAs in HUVEC. This effect was attenuated by pretreatment with a MEK1 inhibitor. Furthermore, hGH treatment increased adhesion of BCECF-labeled THP-1 cells or primary monocytes to HUVEC, and this effect was attenuated by pretreatment with a MEK1 inhibitor.

CONCLUSIONS

VCAM-1 and E-selectin expression was stimulated by GH via the mitogen-activated protein kinase pathway, resulting in augmented adhesion of THP-1 cells and monocytes to HUVEC. These data suggested that GH directly stimulates the development of atherosclerosis.

Drug treatment strategies for secondary diabetes in patients with acromegaly

INTRODUCTION

Acromegaly is a rare disease due to oversecretion of growth hormone (GH). Even though the disease is often portrayed by its most apparent clinical features, given the abundance of GH receptors throughout the body, it truly is a systemic disease leading to numerous complications and comorbidities. A distinct medical issue in the context of acromegaly is diabetes: It can be a complication as a consequence of GH excess and its mediators, but it can also result from treatment of acromegaly.

AREAS COVERED

This review provides an overview of the effects of acromegaly pathophysiology on glucose homeostasis. Furthermore, it devotes an extensive section on the influence that acromegaly treatment has on glucose metabolism, including approved as well as currently investigated drugs. It also summarizes observations from the use of anti-diabetic medication in patients with acromegaly.

EXPERT OPINION

Glucose imbalance is an important aspect of acromegaly comorbidity and deserves more attention. Even though numerous studies have investigated glucose homeostasis in acromegaly, there is still a clear need for more basic, translational, and also clinical research to advance the understanding of the underlying mechanisms and how to best address them.

Persistent inflammation and endothelial dysfunction in patients with treated acromegaly

OBJECTIVE

Acromegaly is characterized by an excess of growth hormone (GH) and insulin-like growth factor 1 (IGF1). Cardiovascular disease (CVD) risk factors are common in acromegaly and often persist after treatment. Both acute and long-lasting pro-inflammatory effects have been attributed to IGF1. Therefore, we hypothesized that inflammation persists in treated acromegaly and may contribute to CVD risk.

METHODS

In this cross-sectional study, we assessed cardiovascular structure and function, and inflammatory parameters in treated acromegaly patients. Immune cell populations and inflammatory markers were assessed in peripheral blood from 71 treated acromegaly patients (with controlled or uncontrolled disease) and 41 matched controls. Whole blood (WB) was stimulated with Toll-like receptor ligands. In a subgroup of 21 controls and 33 patients with controlled disease, vascular ultrasound measurements were performed.

RESULTS

Leukocyte counts were lower in patients with controlled acromegaly compared to patients with uncontrolled acromegaly and controls. Circulating IL18 concentrations were lower in patients; concentrations of other inflammatory mediators were comparable with controls. In stimulated WB, cytokine production was skewed toward inflammation in patients, most pronounced in those with uncontrolled disease. Vascular measurements in controlled patients showed endothelial dysfunction as indicated by a lower flow-mediated dilatation/nitroglycerine-mediated dilatation ratio. Surprisingly, pulse wave analysis and pulse wave velocity, both markers of endothelial dysfunction, were lower in patients, whereas intima-media thickness did not differ.

CONCLUSIONS

Despite treatment, acromegaly patients display persistent inflammatory changes and endothelial dysfunction, which may contribute to CVD risk and development of CVD.

Changes in metabolic parameters and cardiovascular risk factors after therapeutic control of acromegaly vary with the treatment modality. Data from the Bicêtre cohort, and review of the literature

CONTEXT

Untreated acromegaly is associated with increased morbidity and mortality due to malignant, cardiovascular, and cerebrovascular disorders. Effective treatment of acromegaly reduces excess mortality, but its impact on cardiovascular risk factors and metabolic parameters are poorly documented.

AIM

We analyzed changes in cardiovascular risk factors and metabolic parameters in patients receiving various treatment modalities.

PATIENTS AND METHODS

We retrospectively studied 96 patients with acromegaly, both at diagnosis and after IGF-I normalization following surgery alone (n = 51) or medical therapy with first generation somatostatin analogues (SSA, n = 23), or pegvisomant (n = 22). Duration of follow-up was 77 (42-161) months, 75 (42-112) months, and 62 (31-93) months, in patients treated with surgery alone, SSA, and pegvisomant, respectively. In all the cases except four, patients treated medically had underwent previous unsuccessful surgery.

RESULTS

IGF-I normalization was associated with increased body weight, decreased systolic blood pressure (SBP) in hypertensive patients, decreased fasting plasma glucose (FPG) and HOMA-IR and HOMA-B levels, increased HDL cholesterol (HDLc); whereas, LDL cholesterol (LDLc) was not significantly different. Plasma PCSK9 levels were unchanged in patients with available values. Cardiovascular and metabolic changes varied with the treatment modality: surgery, but not pegvisomant, had a beneficial effect on SBP; FPG decreased after surgery but increased after SSA; the decline in HOMA-IR was only significant after surgery; pegvisomant significantly increased LDLc and total cholesterol; whereas SA increased HDLc and had no effect on LDLc levels.

CONCLUSION

Treatments used to normalize IGF-I levels in patients with acromegaly could have differential effects on cardiovascular risk factors and metabolic parameters.

The Endothelium in Acromegaly

Growth hormone (GH) and insulin like growth factor-1 (IGF-1) excess induce well-known deleterious effects on the cardiovascular system, especially after long-term exposition. Acromegaly, a condition of chronic GH and IGF-1 hypersecretion, is frequently associated to cardiovascular complications, although recent studies have shown a reduction in the prevalence of these comorbidities in well-controlled patients and a mortality risk similar to normal aging population. Many factors could contribute to the increased cardiovascular risk of acromegaly patients. Among these factors, the endothelium plays a key role in the pathogenesis of atherosclerotic plaques and could be considered an early marker of atherosclerosis and cardiovascular dysfunction. In this review we examined the relationship between GH/IGF-1 excess and the endothelium, from basic studies to clinical evidence. Many studies involving various arterial districts (microvascular arteries of retina, kidney and brain, and major vessels as carotid and aorta) showed that GH/IGF-1 excess promotes endothelial dysfunction via several different mechanisms. Increased endothelial proliferation, dysfunction of endothelial progenitor cells, increased oxidative stress, and compromised oxidative defenses are the main factors that are associated with endothelial dysfunction. In the general population, these alterations are associated with the development of atherosclerosis with an increased incidence of coronary artery disease and cerebrovascular complications. However, in acromegaly this is still a debated issue, despite the presence of many pro-atherogenic factors and comorbidities, such as hypertension, diabetes, sleep apnoea, and metabolic syndrome. Preclinical markers of atherosclerosis as arterial intima media thickness, pulse wave velocity and flow mediated dilation seem to be impaired in acromegaly and partly mediated by the endothelium dysfunction. In conclusion, the pathophysiology of endothelial dysfunction in the condition of GH and IGF-1 excess remains a crucial area of investigation to fully dissect the association of acromegaly with cardiovascular disease complications.

Insulin Resistance in Patients With Acromegaly

Acromegaly is characterized by chronic overproduction of growth hormone (GH) that leads to insulin resistance, glucose intolerance and, ultimately, diabetes. The GH-induced sustained stimulation of lipolysis plays a major role not only in the development of insulin resistance and prediabetes/diabetes, but also in the reduction of lipid accumulation, making acromegaly a unique case of severe insulin resistance in the presence of reduced body fat. In the present review, we elucidate the effects of GH hypersecretion on metabolic organs, describing the pathophysiology of impaired glucose tolerance in acromegaly, as well as the impact of acromegaly-specific therapies on glucose metabolism. In addition, we highlight the role of insulin resistance in the development of acromegaly-associated complications such as hypertension, cardiac disease, sleep apnea, polycystic ovaries, bone disease, and cancer. Taken together, insulin resistance is an important metabolic hallmark of acromegaly, which is strongly related to disease activity, the development of comorbidities, and might even impact the response to drugs used in the treatment of acromegaly.

The assessment of total antioxidant capacity and superoxide dismutase levels, and the possible role of manganese superoxide dismutase polymorphism in acromegaly

Oxidative status is attributed to endothelial dysfunction and might be one of the key mechanisms of endothelial dysfunction in acromegaly. In this study, we aimed to investigate the effect of acromegaly on superoxide dismutase (SOD) and total antioxidant capacity (TAC) levels, and the possible influence of human manganese superoxide dismutase (MnSOD) polymorphism on these levels. 51 acromegaly patients and 57 age and sex matched healthy subjects were recruited to the study in Bezmialem Vakif University Hospital between 2011 and 2014. The median SOD and TAC levels were 42.7 (33-60) pg/mL and 1,313.7 (155-1,902) μM in acromegaly; and 46.3 (38-95) pg/mL and 1,607.3 (195-1,981) μM in healthy subjects (p < 0.001, p < 0.001). SOD levels were decreased in controlled and uncontrolled patients compared to healthy subjects (p = 0.05 and p = 0.002, respectively). Controlled and uncontrolled acromegaly displayed significantly decreased levels of TAC compared to healthy subjects (p < 0.05 and p < 0.001, respectively). SOD levels were not associated with MnSOD polymorphisms in acromegaly. In conclusion, this study showed that acromegaly was associated with decreased levels of SOD and TAC, and controlling the disease activity could not adequately improve these levels.

Complications of acromegaly: cardiovascular, respiratory and metabolic comorbidities

Acromegaly is associated with an enhanced mortality, with cardiovascular and respiratory complications representing not only the most frequent comorbidities but also two of the main causes of deaths, whereas a minor role is played by metabolic complications, and particularly diabetes mellitus. The most prevalent cardiovascular complications of acromegaly include a cardiomyopathy, characterized by cardiac hypertrophy and diastolic and systolic dysfunction together with arterial hypertension, cardiac rhythm disorders and valve diseases, as well as vascular endothelial dysfunction. Biochemical control of acromegaly significantly improves cardiovascular disease, albeit completely recovering to normal mainly in young patients with short disease duration. Respiratory complications, represented mainly by sleep-breathing disorders, particularly sleep apnea, and respiratory insufficiency, frequently occur at the early stage of the disease and, although their severity decreases with disease control, this improvement does not often change the indication for a specific therapy directed to improve respiratory function. Metabolic complications, including glucose and lipid disorders, are variably reported in acromegaly. Treatments of acromegaly may influence glucose metabolism, and the presence of diabetes mellitus in acromegaly may affect the choice of treatments, so that glucose homeostasis is worth being monitored during the entire course of the disease. Early diagnosis and prompt treatment of acromegaly, aimed at obtaining a strict control of hormone excess, are the best strategy to limit the development or reverse the complications and prevent the premature mortality.

Arterial properties in acromegaly: relation to disease activity and associated cardiovascular risk factors

PURPOSE

Acromegaly is associated with increased cardiovascular morbidity and mortality when inadequately treated, which may be secondary to associated comorbidities or to direct IGF-1 effects on the cardiovascular system. By using a control group carefully matched for traditional cardiovascular risk factors, we aimed to assess the direct contribution of disease activity and IGF-1 levels to arterial damage as assessed by measurements of arterial stiffness and endothelial function.

METHODS

Twenty-nine subjects with acromegaly (11 males, 52 ± 14 year; 15 active acromegaly) and 24 matched controls underwent evaluation of large and small artery compliance using applanation tonometry, pulse wave velocity (PWV), augmentation index (Alx), carotid ultrasonography intima-media thickness, (IMT) and flow-mediated dilatation (FMD).

RESULTS

IGF-1 expressed as times the upper limit of the normal range (x ULN) was 2.2 ± 1.1 in patients with active disease versus 0.7 ± 0.2 in patients in remission. Irrespective of disease activity, FMD was lower in patients with acromegaly than in control subjects, (3.4 ± 2.7 % in active acromegaly, 4.4 ± 3.3 % in controlled acromegaly and 7.5 ± 3.8 % in controls; p = 0.004). There were no significant differences in PWV, Alx, and IMT between groups. A positive correlation was found between IGF-1× ULN and IMT (r = 0.4; P = 0.02). Asymmetric dimethylarginine (ADMA), a novel cardiovascular risk factor, was positively correlated to arterial stiffness (r = 0.46; p = 0.017) and negatively with small vessel compliance (r = -0.44, p = 0.02).

CONCLUSIONS

Patients with acromegaly have significantly impaired endothelial function as assessed by FMD, but other tested vascular parameters were similar to a control group that was adequately matched for cardiovascular risk factors.

Markers of early atherosclerosis, oxidative stress and inflammation in patients with acromegaly

PURPOSE

Data regarding atherosclerosis in acromegaly is controversial in literature. We aimed to investigate the markers of early atherosclerosis, oxidative stress, inflammation and their relationships with each other in acromegaly.

METHODS

Thirty-nine patients with acromegaly and 40 control subjects were enrolled. Patients were classified into two groups; active acromegaly (AA) and controlled acromegaly (CA). Controls were matched by age, gender, body mass index and presence of cardiovascular risk factors. Flow mediated dilatation (FMD), carotid intima media thickness (CIMT), epicardial adipose tissue thickness (EAT) were measured and serum levels of oxidative stress parameters, high mobility group box 1 protein (HMGB1) and high sensitive CRP (hs CRP) were evaluated.

RESULTS

Significantly decreased FMD, increased CIMT and EAT were found in patients with acromegaly compared to controls (p < 0.01, p < 0.05, p < 0.001, respectively). EAT correlated negatively with FMD (r = -0.24, p = 0.038) and positively with CIMT (r = 0.37, p < 0.01). Presence of acromegaly, hypertension and age were found to be the predictors of early atherosclerosis (p < 0.05). Hs CRP was decreased in AA compared to controls (p = 0.01). There were no significant differences for HMGB1 and oxidized LDL (ox-LDL) cholesterol levels and total antioxidant capacity (TAC) between AA, CA and controls (p > 0.05).

CONCLUSION

Early atherosclerosis measured with FMD, CIMT and EAT may exist in acromegaly. However, decreased hs CRP and unchanged HMGB1, ox-LDL and TAC levels suggest that inflammation and oxidative stress do not seem to contribute to the development of atherosclerosis in these patients.

A comprehensive study of clinical, biochemical, radiological, vascular, cardiac, and sleep parameters in an unselected cohort of patients with acromegaly undergoing presurgical somatostatin receptor ligand therapy

CONTEXT

Attainment of safe GH and IGF-1 levels is a central goal of acromegaly management.

OBJECTIVE

The aim of this study was to determine the extent to which reductions in GH and IGF-1 concentrations correlate with amelioration of radiological, metabolic, vascular, cardiac, and respiratory sequelae in a single unselected patient cohort.

STUDY DESIGN

This was a prospective, within-subject comparison in 30 patients with newly diagnosed acromegaly (15 women and 15 men: mean age, 54.3 years; range, 23-78 years) before and after 24 weeks of lanreotide Autogel (ATG) therapy.

RESULTS

Reductions in GH and IGF-1 concentrations and tumor volume were observed in all but 2 patients (median changes [Δ]: GH, -6.88 μg/L [interquartile range -16.78 to -3.32, P = .000001]; IGF-1, -1.95 × upper limit of normal [-3.06 to -1.12, P = .000002]; and pituitary tumor volume, -256 mm(3) [-558 to -72.5, P = .0002]). However, apnea/hypopnea index scores showed highly variable responses (P = .11), which were independent of ΔGH or ΔIGF-1, but moderately correlated with Δweight (R(2) = 0.42, P = .0001). Although systolic (P = .33) and diastolic (P = .76) blood pressure were unchanged, improvements in arterial stiffness (aortic pulse wave velocity, -0.4 m/s [-1.2 to +0.2, P = .046]) and endothelial function (flow mediated dilatation, +1.73% [-0.32 to +6.19, P = .0013]) were observed. Left ventricular mass index regressed in men (-11.8 g/cm(2) [-26.6 to -1.75], P = .019) but not in women (P = .98). Vascular and cardiac changes were independent of ΔGH or ΔIGF-1 and also showed considerable interindividual variation. Metabolic parameters were largely unchanged.

CONCLUSIONS

Presurgical ATG therapy lowers GH and IGF-1 concentrations, induces tumor shrinkage, and ameliorates/reverses cardiac, vascular, and sleep complications in many patients with acromegaly. However, responses vary considerably between individuals, and attainment of biochemical control cannot be assumed to equate to universal complication control.

The cardiovascular system in growth hormone excess and growth hormone deficiency

The clinical conditions associated with GH excess and GH deficiency (GHD) are known to be associated with an increased risk for the cardiovascular morbidity and mortality, suggesting that either an excess or a deficiency in GH and/or IGF-I is deleterious for cardiovascular system. In patients with acromegaly, chronic GH and IGF-I excess commonly causes a specific cardiomyopathy characterized by a concentric cardiac hypertrophy associated with diastolic dysfunction and, in later stages, with systolic dysfunction ending in heart failure if GH/IGF-I excess is not controlled. Abnormalities of cardiac rhythm and anomalies of cardiac valves can also occur. Moreover, the increased prevalence of cardiovascular risk factors, such as hypertension, diabetes mellitus, and insulin resistance, as well as dyslipidemia, confer an increased risk for vascular atherosclerosis. Successful control of the disease is accompanied by a decrease of the cardiac mass and improvement of cardiac function and an improvement in cardiovascular risk factors. In patients with hypopituitarism, GHD has been considered the under- lying factor of the increased mortality when appropriate standard replacement of the pituitary hormones deficiencies is given. Either childhood-onset or adulthood-onset GHD are characterized by a cluster of abnormalities associated with an increased cardiovascular risk, including altered body composition, unfavorable lipid profile, insulin resistance, endothelial dysfunction and vascular atherosclerosis, a decrease in cardiac mass together with an impairment of systolic function mainly after exercise. Treatment with recombinant GH in patients with GHD is followed by an improvement of the cardiovascular risk factors and an increase in cardiac mass together with an improvement in cardiac performance. In conclusion, acromegaly and GHD are associated with an increased risk for cardiovascular morbidity and mortality, but the control of GH/IGF-I secretion reverses cardiovascular abnormalities and restores the normal life expectancy.

Procalcitonin can be used as a marker of premature atherosclerosis in acromegaly

The objective of the study was to evaluate arterial morphologic changes of early atherosclerosis and changes in procalcitonin (PCT) levels in patients with acromegaly according to disease activity. Thirty-three active and 20 inactive acromegaly patients followed at Endocrinology-Metabolism out-patient clinic of Cerrahpasa Medical Faculty between 2004 and 2008 were included in the study. Twenty gender and age matched healthy subjects were included as the control group. Intima-media thickness (IMT) of the carotid arteries was measured by ultrasonography. Blood was drawn for biochemical tests and the serum concentrations of C-reactive protein (CRP) and PCT. Intergroup analysis revealed no significant differences between Growth hormone (GH), insulin like growth factor-1 (IGF-1), and IMT (P = 0.42, P = 0.47 respectively). No significant differences were found in the fibrinogen, CRP and PCT levels of the acromegaly patients and the subjects in the control group (P = 0.57, P = 0.84, P = 0.68 respectively). In the patients with IMT ≥ 1 mm, PCT (0.4 [IQR: 0.4-0.55]) levels were significantly different from the patients without atherosclerosis (0.06 [IQR: 0.05-0.12], P < 0.001). The correlation between IMT and PCT (P = 0.001, r = 0.47) was more significant than the correlation between IMT and CRP (P = 0.01, r = 0.28). There was a positive correlation between IMT and atherosclerotic risk factors such as age (P = 0.01, r = 0.27) and body mass index (BMI; P = 0.005, r = 0.32). Our results showed that PCT increases before CRP and it can be useful for the assessment of premature atherosclerosis in acromegaly as well.

Improvement of cardiac parameters in patients with acromegaly treated with medical therapies

In acromegaly, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) excess results in a specific cardiomyopathy characterized by concentric cardiac hypertrophy primarily associated with diastolic dysfunction that can lead to impaired systolic function and eventually heart failure. This review of the literature evaluates the effect of therapeutic intervention on cardiac parameters. Clinical studies investigating the impact of treatments for acromegaly on cardiac function published between January 1980 and January 2009 were identified through electronic searches of Medline. Suppression of GH and IGF-1 following surgery or medical treatment with somatostatin analogue therapy is effective in decreasing left ventricular (LV) hypertrophy, with subsequent improvement in cardiac function. First-line treatment with somatostatin analogues resulted in improved cardiac outcome compared with first-line surgery, possibly due to somatostatin analogues acting directly through somatostatin receptors on cardiac cells. Additional cardiac improvement has been reported when somatostatin analogue treatment was combined with surgery. In patients where complete biochemical control was not achieved, an improved cardiac performance following treatment with somatostatin analogues has been reported. Treatment with pegvisomant has been demonstrated to reduce LV hypertrophy and improve diastolic and systolic performance. In contrast, reports have suggested that treatment with the dopamine agonist cabergoline increased the incidence of valvular heart disease. Although surgery and somatostatin analogues are effective in improving cardiomyopathy, a greater beneficial effect is observed with somatostatin analogue treatment. Selected patients with acromegaly should consider first-line therapy or pre-treatment with somatostatin analogues prior to surgery to achieve biochemical control and improve cardiac dysfunction.

Ambulatory arterial stiffness indexes in acromegaly

OBJECTIVE

Acromegaly is associated with increased cardiovascular morbidity and mortality and with specific heart and vascular abnormalities. The aim of our study was to investigate arterial stiffness using the ambulatory arterial stiffness index (AASI) and symmetric AASI (Sym-AASI), two indexes derived from 24-h ambulatory blood pressure monitoring (ABPM), in a group of normotensive and hypertensive patients with active acromegaly, compared with normotensive controls (NOR-CTR) or hypertensive controls (HYP-CTR).

SUBJECTS AND METHODS

Ninety-six consecutive patients with active acromegaly (46 males, mean age 49±14 years) underwent 24-h ABPM and evaluation of cardiovascular risk factors. Based on ABPM measurement, acromegalic patients were divided into 64 normotensive (normotensive acromegalic patients (NOR-ACRO)) and 32 hypertensive (hypertensive acromegalic patients (HYP-ACRO)) patients, and were compared with 35 normotensive (NOR-CTR) and 34 hypertensive (HYP-CTR) age-, sex,- and ABPM-matched control subjects.

RESULTS

The AASI and Sym-AASI indexes were significantly higher in acromegalic patients than in controls, either in the normotensive (NOR-ACRO vs NOR-CTR, P<0.0001 for AASI and P=0.005 for Sym-AASI) or in the hypertensive (HYP-ACRO vs HYP-CTR, P=0.01 for AASI and P=0.01 for Sym-AASI) group. Multiple logistic regression analysis showed a significant association of the highest AASI tertile with serum IGF1 (P=0.034) in the whole acromegalic group.

CONCLUSION

AASIs are increased in acromegaly, independent of blood pressure (BP) elevation, and may have an important role in predicting cardiovascular risk in this disease.

Association of serum IGF1 with endothelial function: results from the population-based study of health in Pomerania

OBJECTIVE

IGF1 mediates multiple physiological and pathophysiological responses in the cardiovascular system. The aim of this study was to analyze the association between serum IGF1 as well as IGF-binding protein 3 (IGFBP3) levels and endothelial function measured by flow-mediated dilation (FMD).

DESIGN

Cross-sectional population-based observational study.

METHODS

The study population comprised 1482 subjects (736 women) aged 25-85 years from the Study of Health in Pomerania. Serum IGF1 and IGFBP3 levels were determined by chemiluminescence immunoassays. FMD measurements were performed using standardized ultrasound techniques. FMD values below the sex-specific median were considered low.

RESULTS

In males, logistic regression analyses revealed an odds ratio (OR) of 1.27 (95% confidence interval (CI) 1.07-1.51; P=0.008) for decreased FMD for each decrement of IGF1 s.d. after adjustment for major cardiovascular confounders. In females, no significant relationship between serum IGF1 and FMD was found (OR 0.88, CI 0.74-1.05; P=0.147). After exclusion of subjects with the current use of antihypertensive medication, these findings were similar (males: OR 1.40, CI 1.12-1.75; P=0.003; females: OR 0.95, CI 0.77-1.16; P=0.595). There was no association between serum IGFBP3 levels and FMD in both sexes.

CONCLUSIONS

Low serum IGF1 levels are associated with impaired endothelial function in males. In women, serum IGF1 is not associated with endothelial function.