Coronary microvascular dysfunction may be related to IGF-1 in acromegalic patients and can be restored by therapy

The Heart's Function as a Pump Assessed via Impedance Cardiography and the Autonomic System Balance in Patients with Early-Stage Acromegaly

BACKGROUND

Acromegaly is a rare, chronic disease that involves structural and functional abnormalities of the cardiovascular system. Acromegaly likely affects interactions between the cardiovascular system and the autonomic nervous system (ANS). Therefore, assessing the relationship between sympathetic-parasympathetic balance by analyzing heart rate variability (HRV) and the hemodynamic profile via impedance cardiography (ICG) may be useful in learning the exact nature of interactions between the ANS and the cardiovascular system. The purpose of this study was to assess a possible association between HRV and ICG-based parameters of cardiac function in patients newly diagnosed with acromegaly.

METHODS

This observational cohort study was conducted on 33 patients (18 men, mean age of 47 years) newly diagnosed with acromegaly and no significant comorbidities. A correlation analysis (Spearman's rank coefficient R) of the parameters assessed via ICG and the HRV assessed via 24 h ambulatory electrocardiography was performed. ICG assessments included the following parameters: stroke volume index (SI), cardiac index (CI), acceleration index (ACI), velocity index (VI), and Heather index (HI). The analysis of HRV included both time-domain parameters (pNN50, SDNN, SDSD, rMSSD) and frequency-domain parameters (total power (TP) and its individual frequency bands: low-frequency (LF day/night), high-frequency (HF day/night), and the LF/HF ratio (day/night)).

RESULTS

Frequency-domain HRV analysis showed the following correlations: (1) lower nighttime LF values with higher ACI (R = -0.38; p = 0.027) and HI (R = -0.46; p = 0.007) values; (2) higher nighttime HF values with higher ACI (R = 0.39; p = 0.027) and HI (R = 0.43; p = 0.014) values; (3) lower nighttime LF/HF values with higher ACI (R = -0.36; p = 0.037) and HI (R = -0.42; p = 0.014) values; (4) higher nighttime TP values with higher SI values (R = 0.35; p = 0.049). Time-domain parameters of HRV showed a significant correlation only between the nighttime values of SDSD and SI (R = 0.35; p = 0.049) and between the daytime and nighttime values of SDNN and HR (R = -0.50; p = 0.003 and R = -0.35; p = 0.046). In multivariate regression, only ACI was revealed to be independently related to HRV.

CONCLUSIONS

In patients newly diagnosed with acromegaly, the relationship between the sympathetic-parasympathetic balance assessed via HRV and the hemodynamic profile assessed via ICG was revealed. Better function of the left ventricle was associated with a parasympathetic shift in the autonomic balance.

Can signal peptide-CUB-EGF domain-containing protein 1 (SCUBE-1) be used as an indicator of endothelial dysfunction in acromegaly patients?

PURPOSE

Acromegaly is closely related to increased oxidative stress and endothelial dysfunction (ED). This study aimed to evaluate, for the first time in the literature, signal peptide-CUB-EGF domain-containing protein 1 (SCUBE-1) and endothelial nitric oxide synthase e(NOS) levels in the setting of acromegaly.

METHOD

A total of 56 acromegaly patients and a control group composed of 30 healthy volunteers were included in this study. In the postoperative follow-up, patients were grouped as active or in-remission according to their GH and IGF-1 levels in oral glucose stimulation test (OGST). After detailed physical examination of acromegaly patients and the control subjects, 8-hour fasting blood samples were collected to evaluate biochemical parameters including lipid profile, anterior pituitary hormones, and SCUBE-1 and e(NOS) levels.

RESULTS

Inactive and active acromegaly was noted in 78.6% and 21.4% of patients, respectively. The median (min-max) SCUBE-1 levels were significantly higher in the inactive acromegaly and active acromegaly groups than in the control group (1.6(0.4-2.4) and 1.8(1.1-2.5) vs. 0.4(0.2-1.0) ng/mL, respectively, p < 0.001 for each). The median (min-max) e(NOS) levels were significantly higher in the inactive acromegaly and active acromegaly groups than in the control group (132.7 (26.8-602.9) and 137.3 (69.7-488.7) vs. 83.9 (16.4-218.7) pg/mL, p = 0.018 and p = 0.048, respectively). We have also detected positive correlations of e(NOS) with leukocyte (r = 0.307, p = 0.021) and neutrophil counts (r = 0.309, p = 0.021).

CONCLUSION

Our study revealed for the first time in literature that SCUBE-1 levels, being a novel marker for ED, were significantly higher in acromegaly patients than in control subjects. When supported with clinical studies, SCUBE-1can be used as an early indicator of endothelial damage in acromegaly patients.

Coronary Flow Velocity Reserve by Echocardiography: Beyond Atherosclerotic Disease

Coronary flow velocity reserve (CFVR) is defined as the ratio between coronary flow velocity during maximal hyperemia and coronary flow at rest. Gold-standard techniques to measure CFVR are either invasive or require radiation and are therefore inappropriate for large-scale adoption. More than 30 years ago, echocardiography was demonstrated to be a reliable tool to assess CFVR, and its field of application rapidly expanded. Although initially validated to assess the hemodynamic relevance of a coronary stenosis, CFVR by echocardiography was later used to investigate coronary microcirculation. Microvascular dysfunction was detected in many different conditions, ranging from organ transplantation to inflammatory disorders and from metabolic diseases to cardiomyopathies. Moreover, it has been proven that CFVR by echocardiography not only detects coronary microvascular involvement but is also an effective prognostic factor that allows a precise risk stratification of the patients. In this review, we will summarize the many applications of CFVR by echocardiography, focusing on the coronary involvement of systemic diseases.

New insights on the cardiovascular effects of IGF-1

INTRODUCTION

Cardiovascular (CV) disorders are steadily increasing, making them the world's most prevalent health issue. New research highlights the importance of insulin-like growth factor 1 (IGF-1) for maintaining CV health.

METHODS

We searched PubMed and MEDLINE for English and non-English articles with English abstracts published between 1957 (when the first report on IGF-1 identification was published) and 2022. The top search terms were: IGF-1, cardiovascular disease, IGF-1 receptors, IGF-1 and microRNAs, therapeutic interventions with IGF-1, IGF-1 and diabetes, IGF-1 and cardiovascular disease. The search retrieved original peer-reviewed articles, which were further analyzed, focusing on the role of IGF-1 in pathophysiological conditions. We specifically focused on including the most recent findings published in the past five years.

RESULTS

IGF-1, an anabolic growth factor, regulates cell division, proliferation, and survival. In addition to its well-known growth-promoting and metabolic effects, there is mounting evidence that IGF-1 plays a specialized role in the complex activities that underpin CV function. IGF-1 promotes cardiac development and improves cardiac output, stroke volume, contractility, and ejection fraction. Furthermore, IGF-1 mediates many growth hormones (GH) actions. IGF-1 stimulates contractility and tissue remodeling in humans to improve heart function after myocardial infarction. IGF-1 also improves the lipid profile, lowers insulin levels, increases insulin sensitivity, and promotes glucose metabolism. These findings point to the intriguing medicinal potential of IGF-1. Human studies associate low serum levels of free or total IGF-1 with an increased risk of CV and cerebrovascular illness. Extensive human trials are being conducted to investigate the therapeutic efficacy and outcomes of IGF-1-related therapy.

DISCUSSION

We anticipate the development of novel IGF-1-related therapy with minimal side effects. This review discusses recent findings on the role of IGF-1 in the cardiovascular (CVD) system, including both normal and pathological conditions. We also discuss progress in therapeutic interventions aimed at targeting the IGF axis and provide insights into the epigenetic regulation of IGF-1 mediated by microRNAs.

Genetic Etiology of Ichthyosis in Turkish Patients: Nextgeneration Sequencing Identified Seven Novel Mutations

Objective:

Acromegaly is a rare disease associated with increased mortality. Reports on coronary artery disease in acromegaly are controversial. This study aimed to investigate the possible association of epicardial adipose tissue thickness with cardiovascular risk in patients with acromegaly.

Methods:

The study included 38 patients followed up with the diagnosis of acromegaly and 29 healthy controls. Patients with acromegaly were divided into controlled and uncontrolled acromegaly groups based on insulin-like growth factor-1 levels. Epicardial adipose tissue thickness measurements were obtained from chest computed tomography, and laboratory data were extracted from patient files.

Results:

Twenty-nine patients (76.3%) had controlled acromegaly. Eleven patients with acromegaly had diabetes mellitus (28.9%), 18 (47.4%) had hypertension, and 27 (71%) had a concomitant chronic disease. Epicardial adipose tissue thickness was significantly increased in the acromegaly group (p<0.001). No significant difference was observed between the controlled and uncontrolled acromegaly groups in terms of the epicardial adipose tissue thickness. Age was the only parameter that was significantly correlated with the epicardial adipose tissue thickness. When the Framingham risk score was calculated, the 10-year cardiovascular risk of patients with acromegaly was 5.63%.

Conclusions:

The epicardial adipose tissue thickness is increased in acromegaly. However, this increase may not have clinical relevance in terms of cardiovascular risk.

Alteration in choroidal microvasculature determined by optical coherence tomography angiography in patients with acromegaly

AIM

We aimed to investigate the retinal layers and macular capillary structure using optical coherence tomography angiography (OCTA) with acromegaly patients and determine the relationship between OCTA parameters and disease duration, Growth hormone (GH) and Insuline growth factor (IGF - 1) levels.

PATIENTS AND METHOD

Twenty-two patients with acromegaly who were followed up in the endocrinology outpatient clinic of Sisli Hamidiye Etfal Health Training and Research Hospital, were recruited into the study. Healthy control group was consisted of 22 age and gender matched subjects. Complete opthalmological examination including best visual acuity (BCVA), axial lenght, intraocular pressure (IOP) measurement, anterior segment and fundus examination, central corneal thickness with pachymetry and OCTA measurement were performed in the patients and healthy control group. Foveal avascular zone (FAZ), foveal vascular density (FVD), parafoveal vascular density (PFVD), choroidal flow (CF), foveal thickness (FT) and choroidal thickness (CT) were compared beetwen groups. Correlation between disease duration, GH and IGF-1 levels and OCTA parameters were evaluated.

RESULTS

There was no statistically significant difference between the groups in terms of BCVA, axial length, IOP, FT, FAZ, FD and PFVD. Choroidal thickness and CF was significantly high in the patients group compared to healthy controls (respectively, p = 0.003, p = 0.022). The mean follow-up period in patients with acromegaly was 90±50.2 months. There was a significant correlation between GH and subfoveal choroidal thickness in the patient group (p < 0.001, r = 0.52), a significant correlation was determined between disease duration and corneal thickness (p = 0.01, r = 0.41). In addition, an inverse correlation was detected between the IGF-1 level and the FAZ domain (p = 0.022, r= -0.34).

CONCLUSION

In patients with acromegaly, choroidal vasculature seems to be more affected than the retinal vasculature.

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.

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.

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.

Acromegaly and ultrasound: how, when and why?

BACKGROUND

Acromegaly is a rare disease caused by an excess of growth hormone and insulin-like growth factor 1. It is usually diagnosed because of typical signs such as macroglossia, acral enlargement, jaw prognathism and malocclusion. Systemic complications are a major cause of morbidity and mortality in acromegaly, and many patients remain undiagnosed for several years. Increased ultrasound (US) application in the general population, and including among acromegaly patients, has revealed many suggestive features which, taken together with clinical suspicion, could induce suspicion of this disease.

PURPOSE

This review describes main US features in acromegaly. Echocardiography shows a typical cardiomyopathy, characterized by left ventricular hypertrophy, diastolic and systolic dysfunction, aortic and mitral regurgitation, and increased aortic root diameters. US preclinical markers of atherosclerosis, such as intima media thickness (IMT), seem also to be impaired. Visceromegaly and increased organ stiffness are other features of acromegaly, including enlarged prostate, kidneys, liver, and thyroid. In addition, other US findings are: renal cysts, micronephrolithiasis, impairment of renal haemodynamic parameters, gallstones and gallbladder polyps, hepatic steatosis, thyroid nodules, multinodular goiter, and polycystic ovaries. Musculoskeletal US findings are increased cartilage thickness, impaired density and elasticity of bones, nerve enlargement, carpal and cubital tunnel syndrome, and trigger finger.

CONCLUSIONS

Acromegaly patients frequently present systemic complications and a diagnostic delay. US features of acromegaly are not specific, but could potentially have a key role in early detection of the disease in the presence of typical clinical features.

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.