The GH/IGF-1 Axis and Heart Failure

Identification of dilated cardiomyopathy-linked key genes by bioinformatics methods and evaluating the impact of tannic acid and monosodium glutamate in rats

Dilated cardiomyopathy (DCM) is the most common type of myocardial dysfunction, affecting mostly young adults, but its therapeutic diagnosis and biomarkers for prognosis are lacking. This study aimed to investigate the possible effect of the common food additive monosodium glutamate (MSG) and tannic acid (TA), a phenolic compound, on the key molecular actors responsible for DCM. DCM-related publicly available microarray datasets (GSE120895, GSE17800, and GSE19303) were downloaded from the comprehensive Gene Expression Omnibus (GEO) database, and analyzed to identify differentially expressed genes (DEGs). By integrating DEGs and gene-disease validity curation results, overlapping genes were screened and identified as hub genes. Protein-protein interaction (PPI) network and ontology analysis were performed to make sense of the identified biological data. Finally, mRNA expression changes of identified hub genes in the heart tissues of rats treated with MSG and TA were measured by the qPCR method. Six upregulated (IGF1, TTN, ACTB, LMNA, EDN1, and NPPB) DEGs were identified between the DCM and healthy control samples as the hub genes. qPCR results revealed that the mRNA levels of these genes involved in DCM development increased significantly in rat heart tissues exposed to MSG. In contrast, this increase was remarkably alleviated by TA treatment. Our results provide new insights into critical molecular mechanisms that should be focused on in future DCM studies. Moreover, MSG may play a critical role in DCM formation, and TA may be used as a promising therapeutic agent in DCM.

Back Up at the Pump? I Have a Gut Feeling About This: A Review of the Gastrointestinal Manifestations From Congestive Heart Failure

Heart failure, which is a clinical syndrome characterized by the heart's inability to maintain adequate cardiac output, is known to affect various organ systems in the body due to its ischemic nature and activation of the systemic immune response, but the resultant complications specifically on the gastrointestinal tract and the liver are not well discussed and poorly understood. Gastrointestinal-related phenomena are common symptoms experienced in patients with heart failure and frequently found to increase morbidity and mortality in these populations. The relationship between the gastrointestinal tract and heart failure are strongly linked and influence each other much so that the bidirectional association of the two is oftentimes referred to as cardiointestinal syndrome. Manifestations include gastrointestinal prodrome, bacterial translocation and protein-losing gastroenteropathy by gut wall edema, cardiac cachexia, hepatic insult and injury, and ischemic colitis. More attention is needed from a cardiology perspective to recognize these common presenting gastrointestinal phenomena that affect much of our patient population with heart failure. In this overview, we describe the association between heart failure and the gastrointestinal tract, the pathophysiology, lab findings, clinical manifestations and complications, and the management involved.

Diastolic Dysfunction with Normal Ejection Fraction and Reduced Heart Rate in Mice Expressing Human Growth Hormone and Displaying Signs of Growth Hormone Insufficiency

Growth hormone (GH) signaling is essential for heart development. Both GH deficiency and excess raise cardiovascular risk. Human (h) and mouse (m) GH differ structurally and functionally: hGH binds both the GH receptor (GHR) and prolactin receptor (PRLR), whereas mGH binds only GHR; thus, there is the potential for differential effects. We generated transgenic (hGH-TG) mice that produce pituitary hGH in response to hypothalamic signaling. These mice grow at the same rate as mGH-expressing wild-type (mGH-WT) mice but are smaller and have higher body fat. Echocardiography was used here to compare hGH-TG and mGH-WT mouse hearts. Male hGH-TG mice show a 48% lower left ventricular mass, 36% lower stroke volume, and 48% reduced cardiac output, resembling GH deficiency. Diastolic dysfunction, restrictive ventricular filling, and lower heart rate are suggested in hGH-TG mice. No significant differences in ejection fraction or fractional shortening were observed, even after high-fat diet (HFD) stress. HFD did not affect RNA markers of cardiac damage, although a possible association between B-type natriuretic peptide RNA levels and heart rate was detected. These observations suggest that diastolic dysfunction related to hGH and/or low GH might be offset by a lower heart rate, while structural changes precede functional effects.

Evaluation of potential novel biomarkers for feline hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common cardiomyopathy in cats. The diagnosis can be difficult, requiring advanced echocardiographic skills. Additionally, circulating biomarkers (N-terminal pro-B type natriuretic peptide and cardiac troponin I) have several limitations when used for HCM screening. In previous work, we identified interleukin 18 (IL-18), insulin-like growth factor binding protein 2 (IGFBP-2), brain-type glycogen phosphorylase B (PYGB), and WNT Family Member 5 A (WNT5A) as myocardial genes that show significant differential expression between cats with HCM and healthy cats. The products of these genes are released into the circulation, and we hypothesized that IL-18, IGFBP-2, PYGB, and WNT5A serum RNA and protein concentrations differ between healthy cats, cats with subclinical HCM, and those with HCM and congestive heart failure (HCM + CHF). Reverse transcriptase quantitative polymerase chain reaction (RTqPCR) and enzyme-linked immunosorbent assay (ELISA) were applied to evaluate gene and protein expression, respectively, in the serum of eight healthy controls, eight cats with subclinical HCM, and six cats with HCM + CHF. Serum IGFBP-2 RNA concentrations were significantly different among groups and were highest in cats with subclinical HCM. Compared to healthy controls, serum IL-18 and WNT5A gene expression were significantly higher in cats with HCM + CHF, and WNT5A was higher in cats with subclinical HCM. No differences were observed for PYGB. These results indicate that further investigation via large scale clinical studies for IGFBP-2, WNT5A, and IL-18 may be valuable in diagnosing and staging feline HCM.

A new approach of nano-metformin as a protector against radiation-induced cardiac fibrosis and inflammation via CXCL1/TGF-Β pathway

The present work investigates the potential role of metformin nanoparticles (MTF-NPs) as a radio-protector against cardiac fibrosis and inflammation induced by gamma radiation via CXCL1/TGF-β pathway. Lethal dose fifty of nano-metformin was determined in mice, then 21 rats (male albino) were equally divided into three groups: normal control (G1), irradiated control (G2), and MTF-NPs + IRR (G3). The possible protective effect of MTF-NPs is illustrated via decreasing cardiac contents of troponin, C-X-C motif Ligand 1 (CXCL1), tumor growth factor β (TGF-β), protein kinase B (AKT), and nuclear factor-κB (NF-κB). Also, the positive effect of MTF-NPs on insulin-like growth factor (IGF) and platelet-derived growth factor (PDGF) in heart tissues using immunohistochemical technique is illustrated in the present study. Histopathological examination emphasizes the biochemical findings. The current investigation suggests that MTF-NPs might be considered as a potent novel treatment for the management of cardiac fibrosis and inflammation in patients who receive radiotherapy or workers who may be exposed to gamma radiation.

New Insights into IGF-1 Signaling in the Heart

Insulin-like growth factor-1 (IGF-1) signaling has multiple physiological roles in cellular growth, metabolism, and aging. Myocardial hypertrophy, cell death, senescence, fibrosis, and electrical remodeling are hallmarks of various heart diseases and contribute to the progression of heart failure. This review highlights the critical role of IGF-1 and its cognate receptor in cardiac hypertrophy, aging, and remodeling.

The Double-Edged Sword of Total Antioxidant Capacity: Clinical Significance and Personal Experience

Oxidative stress (OS) could be a condition underlying several human diseases, despite the physiological role of reactive oxygen species (oxidative eustress). Therefore, antioxidant compounds could represent a modulatory mechanism for maintaining a proper redox balance and redox signaling. When antioxidants are insufficient or overwhelmed, OS ensues, causing multiple damages at molecular, tissue, and cellular levels. This study focuses on the role of total antioxidant capacity (TAC) as a biomarker to be interpreted according to several clinical scenarios. After a brief description of various assay methods to elucidate terminology and physiopathological roles, we focus on the hormonal influence on TAC in blood plasma and other biological fluids, as different endocrine systems can modulate the antioxidant response. Furthermore, OS characterizes several endocrinopathies through different mechanisms: an inadequate antioxidant response to an increase in reducing equivalents (reductive distress) or a marked consumption of antioxidants (oxidative distress), which leads to low TAC values. An increased TAC could instead represent an adaptive mechanism, suggesting a situation of OS. Hence, the clinical context is fundamental for a correct interpretation of TAC. This review aims to provide the reader with a general overview of oxidative stress in several clinical examples of endocrine relevance, such as metabolic syndrome, non-thyroid illness syndrome, hypopituitarism, and infertility. Finally, the impact of dietary and surgical interventions on TAC in the model of metabolic syndrome is highlighted, along with personal experience.

[Unfavourable cardiovascular consequences of adult growth hormone deficiency]

The growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis plays a crucial role in maintaining the normal function of the cardiovascular system. Results of the last decades demonstrated that GH-IGF-1 takes part in regulating peripheral resistance and contributes to preserving physiological cardiac mass and left ventricular function. Vasculoprotective functions of the GH-IGF-1 axis are believed to counteract atherosclerosis. Unlike in childhood, when GH-deficiency results in growth retardation, GH deficiency does not cause specific symptoms in adults. Adult growth hormone deficiency (AGHD) is characterized by a clustering of cardiometabolic risk factors resulting in a clinical picture similar to the metabolic syndrome. Besides visceral obesity, dyslipidemia and insulin resistance, novel cardiovascular risk factors, such as chronic low-grade inflammation, oxidative stress and prothrombotic state have also been reported in AGHD and may contribute to the increased cardiometabolic risk. Based on a growing body of evidence, long-term GH-replacement improves lipid profile significantly and has a favorable impact on body composition, endothelial function, left ventricular mass as well as the novel, non-traditional cardiometabolic risk factors. Increased mortality associated with the disease is now considered to be multicausal and as such cannot be solely attributed to the GH-deficiency. The etiology of GH-deficiency, treatment of the underlying pathology as well as the inadequate treatment of coexisting hormonal deficiencies might also be responsible for the increased mortality. Nevertheless, in hypopituitarism, adequate replacement therapy including GH-substitution may result in a mortality that is comparable to the general population. Orv Hetil. 2023; 164(41): 1616-1627.

Regional Handling and Prognostic Performance of Circulating Insulin-Like Growth Factor Binding Protein-7 in Heart Failure

BACKGROUND

Regional handling and the prognostic performance of insulin-like growth factor binding protein (IGFBP)-7, in contrast or in combination with other candidate biomarkers, in chronic heart failure (CHF) remain uncertain.

OBJECTIVES

The authors investigated the regional handling of plasma IGFBP-7 and its association with long-term outcomes in CHF in comparison with selected circulating biomarkers.

METHODS

Plasma concentrations of IGFBP-7, N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity troponin-T, growth differentiation factor-15, and high-sensitivity C-reactive protein were measured prospectively in a cohort with CHF (n = 863). The primary outcome was the composite of heart failure (HF) hospitalization or all-cause mortality. In a separate non-HF cohort (n = 66) undergoing cardiac catheterization, transorgan gradients of plasma IGFBP-7 concentrations were evaluated.

RESULTS

Among 863 patients (age 69 ± 14 years, 30% female, 36% HF with preserved ejection fraction), IGFBP-7 (median: 121 [IQR: 99-156] ng/mL) related inversely to left ventricular volumes but directly to diastolic function. Above the optimal cutoff, IGFBP-7 ≥110 ng/mL was independently associated with 32% increased hazard of the primary outcome: 1.32 (95% CI: 1.06-1.64). Among the 5 markers, IGFBP-7 had the highest hazard for a proportional increment in plasma concentrations independent of HF phenotype in single- and double-biomarker models, and provided incremental prognostic value beyond clinical predictors plus NT-proBNP, high-sensitivity troponin-T, and high-sensitivity C-reactive protein (P < 0.05). Assessment of regional concentrations indicated renal secretion of IGFBP-7 in contrast to renal extraction of NT-proBNP, possible cardiac extraction of IGFBP-7 in contrast to secretion of NT-proBNP, and common hepatic extraction of both peptides.

CONCLUSIONS

Transorgan regulation of IGFBP-7 is distinct from NT-proBNP. Circulating IGFBP-7 independently predicts adverse outcomes in CHF with a strong prognostic performance when compared with other well-recognized cardiac-specific or noncardiac prognostic markers.

Association between insulin-like growth factor-1 and cardiovascular events: a systematic review and dose-response meta-analysis of cohort studies

BACKGROUND

Insulin-like growth factor-1 (IGF-1) has increasingly been reported as linked to cardiovascular (CV) events; however, reported results have been inconsistent, and no meta-analysis has been undertaken to quantitatively assess this association.

METHODS

We searched PubMed, Embase, and Web of Science databases for cohort articles published up to December 1, 2020. Fixed or random-effects models were used to estimate the summary relative risks (RRs) and 95% confidence intervals (CIs) of CV events in relation to IGF-1. Restricted cubic splines were used to model the dose-response association.

RESULTS

We identified 11 articles (thirteen cohort studies) covering a total of 22,995 participants and 3040 CV events in this meta-analysis. The risk of overall CV events reduced by 16% from the highest to the lowest IGF-1 levels (RR 0.83, 95% CI 0.72-0.95), while the occurrence of CV events reduced by 28% (RR 0.72, 95% CI 0.56-0.92), but not for CV deaths, however (RR 1.00, 95% CI 0.65-1.55). We also found linear associations between IGF-1 levels and CV events. With each per 45 μg/mL IGF-1 increase, the pooled RRs were 0.91 (95% CI 0.86-0.96), 0.91 (95% CI 0.85-0.97) and 0.91 (95% CI 0.84-0.98) for overall CV events, for the occurrence of CV events, and for CV deaths, respectively.

CONCLUSIONS

Our findings based on cohort studies support the contention that any increase in IGF-1 is helpful in reducing the overall risk of CV events. As an important biomarker for assessing the likelihood of CV events, IGF-1 appears to offer a promising prognostic approach for aiding prevention.

The IGF-1R Inhibitor NVP-AEW541 Causes Insulin-Independent and Reversible Cardiac Contractile Dysfunction

The antitumor treatment NVP-AEW541 blocks IGF-1R. IGF-1R signaling is crucial for cardiac function, but the cardiac effects of NVP-AEW541 are ill defined. We assessed NVP-AEW541′s effects on cardiac function and insulin response in vivo and in isolated working hearts. We performed a dose–response analysis of NVP-AEW541 in male, 3-week-old rats and assessed the chronic effects of the clinically relevant dose in adult rats. We performed glucose tolerance tests and echocardiography; assessed the expression and phosphorylation of InsR/IGF-1R and Akt in vivo; and measured substrate oxidation, contractile function, and insulin response in the isolated working hearts. NVP-AEW541 caused dose-dependent growth retardation and impaired glucose tolerance in the juvenile rats. In the adults, NVP-AEW541 caused a continuously worsening depression of cardiac contractility, which recovered within 2 weeks after cessation. Cardiac Akt protein and phosphorylation were unchanged and associated with InsR upregulation. An acute application of NVP-AEW541 in the working hearts did not affect cardiac power but eliminated insulin’s effects on glucose and fatty acid oxidation. The systemic administration of NVP-AEW541 caused dose- and time-dependent impairment of glucose tolerance, growth, and cardiac function. Because cardiac insulin signaling was maintained in vivo but absent in vitro and because contractile function was not affected in vitro, a direct link between insulin resistance and contractile dysfunction appears unlikely.

SIRPα Mediates IGF1 Receptor in Cardiomyopathy Induced by Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is characterized by increased myocardial mass despite near-normal blood pressure, suggesting the presence of a separate trigger. A potential driver is SIRPα (signal regulatory protein alpha)-a mediator impairing insulin signaling. The objective of this study is to assess the role of circulating SIRPα in CKD-induced adverse cardiac remodeling.

METHODS

SIRPα expression was evaluated in mouse models and patients with CKD. Specifically, mutant, muscle-specific, or cardiac muscle-specific SIRPα KO (knockout) mice were examined after subtotal nephrectomy. Cardiac function was assessed by echocardiography. Metabolic responses were confirmed in cultured muscle cells or cardiomyocytes.

RESULTS

We demonstrate that SIRPα regulates myocardial insulin/IGF1R (insulin growth factor-1 receptor) signaling in CKD. First, in the serum of both mice and patients, SIRPα was robustly secreted in response to CKD. Second, cardiac muscle upregulation of SIRPα was associated with impaired insulin/IGF1R signaling, myocardial dysfunction, and fibrosis. However, both global and cardiac muscle-specific SIRPα KO mice displayed improved cardiac function when compared with control mice with CKD. Third, both muscle-specific or cardiac muscle-specific SIRPα KO mice did not significantly activate fetal genes and maintained insulin/IGF1R signaling with suppressed fibrosis despite the presence of CKD. Importantly, SIRPα directly interacted with IGF1R. Next, rSIRPα (recombinant SIRPα) protein was introduced into muscle-specific SIRPα KO mice reestablishing the insulin/IGF1R signaling activity. Additionally, overexpression of SIRPα in myoblasts and cardiomyocytes impaired pAKT (phosphorylation of AKT) and insulin/IGF1R signaling. Furthermore, myotubes and cardiomyocytes, but not adipocytes treated with high glucose or cardiomyocytes treated with uremic toxins, stimulated secretion of SIRPα in culture media, suggesting these cells are the origin of circulating SIRPα in CKD. Both intracellular and extracellular SIRPα exert biologically synergistic effects impairing intracellular myocardial insulin/IGF1R signaling.

CONCLUSIONS

Myokine SIRPα expression impairs insulin/IGF1R functions in cardiac muscle, affecting cardiometabolic signaling pathways. Circulating SIRPα constitutes an important readout of insulin resistance in CKD-induced cardiomyopathy.

The Translation and Commercialisation of Biomarkers for Cardiovascular Disease—A Review

As a leading cause of mortality and morbidity worldwide, cardiovascular disease and its diagnosis, quantification, and stratification remain significant health issues. Increasingly, patients present with cardiovascular disease in the absence of known risk factors, suggesting the presence of yet unrecognized pathological processes and disease predispositions. Fortunately, a host of emerging cardiovascular biomarkers characterizing and quantifying ischaemic heart disease have shown great promise in both laboratory settings and clinical trials. These have demonstrated improved predictive value additional to widely accepted biomarkers as well as providing insight into molecular phenotypes beneath the broad umbrella of cardiovascular disease that may allow for further personalized treatment regimens. However, the process of translation into clinical practice – particularly navigating the legal and commercial landscape – poses a number of challenges. Practical and legal barriers to the biomarker translational pipeline must be further considered to develop strategies to bring novel biomarkers into the clinical sphere and apply these advances at the patient bedside. Here we review the progress of emerging biomarkers in the cardiovascular space, with particular focus on those relevant to the unmet needs in ischaemic heart disease.

Effects of adult growth hormone deficiency and replacement therapy on the cardiometabolic risk profile

Adult growth hormone deficiency (AGHD) is considered a rare endocrine disorder involving patients with childhood-onset and adult-onset growth hormone deficiency (AoGHD) and characterized by adverse cardiometabolic risk profile. Besides traditional cardiovascular risk factors, endothelial dysfunction, low-grade inflammation, impaired adipokine profile, oxidative stress and hypovitaminosis D may also contribute to the development of premature atherosclerosis and higher cardiovascular risk in patients with AGHD. Growth hormone replacement has been proved to exert beneficial effects on several cardiovascular risk factors, but it is also apparent that hormone substitution in itself does not eliminate all cardiometabolic abnormalities associated with the disease. Novel biomarkers and diagnostic techniques discussed in this review may help to evaluate individual cardiovascular risk and identify patients with adverse cardiometabolic risk profile. In the absence of disease-specific guidelines detailing how to assess the cardiovascular status of these patients, we generally recommend close follow-up of the cardiovascular status as well as low threshold for a more detailed evaluation.

Cardiopulmonary coupling and serum cardiac biomarkers in obesity hypoventilation syndrome and obstructive sleep apnea with morbid obesity

STUDY OBJECTIVES

The main cause of death in patients with obesity hypoventilation syndrome (OHS) is cardiac rather than respiratory failure. Here, we investigated autonomic-respiratory coupling and serum cardiac biomarkers in patients with OHS and obstructive sleep apnea (OSA) with comparable body mass index (BMI) and apnea-hypopnea index (AHI).

METHODS

Cardiopulmonary coupling (CPC) and cyclic variation of heart rate (CVHR) analysis was performed on the electrocardiogram signal from the overnight polysomnogram. Cardiac serum biomarkers were obtained in patients with OHS and OSA with a BMI > 40kg/m². Samples were obtained at baseline and after 3 months of positive airway pressure (PAP) therapy in both groups.

RESULTS

Patients with OHS (n=15) and OSA (n=36) were recruited. No group differences in CPC, CVHR and serum biomarkers were observed at baseline and after 3 months of PAP therapy. An improvement in several CPC metrics, including the sleep apnea index, unstable sleep (low frequency coupling and elevated low frequency coupling narrow band [e-LFC_NB]) and CVHR were observed in both groups with PAP use. However, distinct differences in response characteristics were noted. e-LFC_NB coupling correlated with highly sensitive troponin (hs-troponin-T, p<0.05) in the combined cohort. Baseline hs-troponin-T inversely correlated with awake oxygen saturation in the OHS group (p<0.05).

CONCLUSIONS

PAP therapy can significantly improve CPC stability in obese patients with OSA or OHS, with key differences. e-LFC_NB may function as a surrogate biomarker for early subclinical cardiac disease. Low awake oxygen saturation could also increase this biomarker in OHS.

CLINICAL TRIAL REGISTRATION

Registry: Australian New Zealand Clinical Trials Registry; Name: Obesity Hypoventilation Syndrome and Neurocognitive Dysfunction; URL: https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=367492; Identifier: ACTRN12615000122550.

Association of thyroid-stimulating hormone with corrected QT interval variation: A prospective cohort study among patients with type 2 diabetes

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) have a prolonged QT interval and are at high risk of sudden cardiac death. A prolonged QT interval, indicative of impaired ventricular repolarization, is a risk factor for lethal ventricular arrhythmias, such as torsades-de-pointes (TdP).

AIMS

To identify key clinical and biochemical covariates associated with Fridericia's corrected QT interval (QTcF) among euthyroid patients with T2DM, and to describe the temporal relationship between these factors and QTcF.

METHODS

We performed prospective, clinical, biochemical and electrocardiographic measurements among patients with T2DM enrolled in the DIACART study at Pitié-Salpêtrière Hospital, at T1 (baseline) and T2 (follow-up), with a median interval of 2.55 years.

RESULTS

Mean age (63.9±8.5 years), sex (22.35% women), drugs with known risk of TdP according to the CredibleMeds website (Cred-drugsTdP) and serum thyroid-stimulating hormone (TSH) concentrations correlated with QTcF in univariate analysis at both T1 and T2. In multivariable analysis, all these covariates except age were significantly associated with QTcF at both T1 (women: standardized β=0.24±0.07, P=0.001; Cred-drugsTdP: β=0.19±0.07, P=0.007; TSH concentration: β=0.18±0.07, P=0.01) and T2 (women: β=0.25±0.08, P=0.002; Cred-drugsTdP: β=0.25±0.08, P=0.001; TSH concentration: β=0.19±0.08, P=0.01). Furthermore, variation in QTcF over the years was associated with variation in TSH concentration (r=0.24, P=0.007) and changes in use of Cred-drugsTdP (r=0.2, P=0.02).

CONCLUSIONS

Serum TSH concentration and its variation were associated with QTcF and its variation, even after correcting for the main determinants of QTcF. Interventional optimization of TSH concentration in T2DM warrants further investigation to establish its impact on the risk of TdP and sudden cardiac death.

Relevance of nutritional assessment and treatment to counteract cardiac cachexia and sarcopenia in chronic heart failure

Chronic heart failure (CHF) is frequently associated with the involuntary loss of body weight and muscle wasting, which can determine the course of the disease and its prognosis. While there is no gold standard malnutrition screening tool for their detection in the CHF population, several bioelectrical and imaging methods have been used to assess body composition in these patients (such as Dual Energy X-Ray Absorptiometry and muscle ultrasound, among other techniques). In addition, numerous nutritional biomarkers have been found to be useful in the determination of the nutritional status. Nutritional considerations include the slow and progressive supply of nutrients, avoiding high volumes, which could ultimately lead to refeeding syndrome and worsen the clinical picture. If oral feeding is insufficient, hypercaloric and hyperproteic supplementation should be considered. β-Hydroxy-β-methylbutyrate and omega-3 polyunsaturated fatty acid administration prove to be beneficial in certain patients with CHF, and several interventional studies with micronutrient supplementation have also described their possible role in these subjects. Taking into account that CHF is sometimes associated with gastrointestinal dysfunction, parenteral nutritional support may be required in selected cases. In addition, potential therapeutic options regarding nutritional state and muscle wasting have also been tested in clinical studies. This review summarises the scientific evidence that demonstrates the necessity to carry out a careful nutritional evaluation and nutritional treatment to prevent or improve cardiac cachexia and sarcopenia in CHF, as well as improve its course.

IGF-1 protects against angiotensin II-induced cardiac fibrosis by targeting αSMA

The insulin-like growth factor 1 receptor (IGF-1R) signaling in cardiomyocytes is implicated in physiological hypertrophy and myocardial aging. Although fibroblasts account for a small amount of the heart, they are activated when the heart is damaged to promote cardiac remodeling. However, the role of IGF-1R signaling in cardiac fibroblasts is still unknown. In this study, we investigated the roles of IGF-1 signaling during agonist-induced cardiac fibrosis and evaluated the molecular mechanisms in cultured cardiac fibroblasts. Using an experimental model of cardiac fibrosis with angiotensin II/phenylephrine (AngII/PE) infusion, we found severe interstitial fibrosis in the AngII/PE infused myofibroblast-specific IGF-1R knockout mice compared to the wild-type mice. In contrast, low-dose IGF-1 infusion markedly attenuated AngII-induced cardiac fibrosis by inhibiting fibroblast proliferation and differentiation. Mechanistically, we demonstrated that IGF-1-attenuated AngII-induced cardiac fibrosis through the Akt pathway and through suppression of rho-associated coiled-coil containing kinases (ROCK)2-mediated α-smooth muscle actin (αSMA) expression. Our study highlights a novel function of the IGF-1/IGF-1R signaling in agonist-induced cardiac fibrosis. We propose that low-dose IGF-1 may be an efficacious therapeutic avenue against cardiac fibrosis.

Pituitary Dysfunction as a Cause of Cardiovascular Disease

The hypothalamic-pituitary axis is responsible for the neuroendocrine control of several organ systems. The anterior pituitary directly affects the functions of the thyroid gland, the adrenal glands, and gonads, and regulates growth and milk production. The posterior hypophysis, through nerve connections with the hypothalamic nuclei, releases vasopressin and oxytocin responsible for water balance and social bonding, sexual reproduction and childbirth, respectively. Pituitary gland hormonal excess or deficiency results in dysregulation of metabolic pathways and mechanisms that are important for the homeostasis of the organism and are associated with increased morbidity and mortality. Cardiovascular (CV) disorders are common in pituitary disease and have a significant impact on survival. Hormonal imbalance is associated with CV complications either through direct effects on the heart structure and function and vasculature or indirectly by altering the metabolic profile. Optimal endocrine control can prevent or reverse CV defects and preserve survival and quality of life. In this review, we discuss the effects of pituitary hormone excess and deficiency on the CV system. Specifically, we assess the impact of Somatotroph, Corticotroph, Gonadotroph, and Lactotroph anterior pituitary axes on the CV system. The effect of posterior pituitary function on the CV system is also explored.

Late Health Effects of Partial Body Irradiation Injury in a Minipig Model Are Associated with Changes in Systemic and Cardiac IGF-1 Signaling

Clinical, epidemiological, and experimental evidence demonstrate non-cancer, cardiovascular, and endocrine effects of ionizing radiation exposure including growth hormone deficiency, obesity, metabolic syndrome, diabetes, and hyperinsulinemia. Insulin-like growth factor-1 (IGF-1) signaling perturbations are implicated in development of cardiovascular disease and metabolic syndrome. The minipig is an emerging model for studying radiation effects given its high analogy to human anatomy and physiology. Here we use a minipig model to study late health effects of radiation by exposing male Göttingen minipigs to 1.9–2.0 Gy X-rays (lower limb tibias spared). Animals were monitored for 120 days following irradiation and blood counts, body weight, heart rate, clinical chemistry parameters, and circulating biomarkers were assessed longitudinally. Collagen deposition, histolopathology, IGF-1 signaling, and mRNA sequencing were evaluated in tissues. Our findings indicate a single exposure induced histopathological changes, attenuated circulating IGF-1, and disrupted cardiac IGF-1 signaling. Electrolytes, lipid profiles, liver and kidney markers, and heart rate and rhythm were also affected. In the heart, collagen deposition was significantly increased and transforming growth factor beta-1 (TGF-beta-1) was induced following irradiation; collagen deposition and fibrosis were also observed in the kidney of irradiated animals. Our findings show Göttingen minipigs are a suitable large animal model to study long-term effects of radiation exposure and radiation-induced inhibition of IGF-1 signaling may play a role in development of late organ injuries.

New aspects of endocrine control of atrial fibrillation and possibilities for clinical translation

Hormones are potent endo-, para-, and autocrine endogenous regulators of the function of multiple organs, including the heart. Endocrine dysfunction promotes a number of cardiovascular diseases, including atrial fibrillation (AF). While the heart is a target for endocrine regulation, it is also an active endocrine organ itself, secreting a number of important bioactive hormones that convey significant endocrine effects, but also through para-/autocrine actions, actively participate in cardiac self-regulation. The hormones regulating heart-function work in concert to support myocardial performance. AF is a serious clinical problem associated with increased morbidity and mortality, mainly due to stroke and heart failure. Current therapies for AF remain inadequate. AF is characterized by altered atrial function and structure, including electrical and profibrotic remodelling in the atria and ventricles, which facilitates AF progression and hampers its treatment. Although features of this remodelling are well-established and its mechanisms are partly understood, important pathways pertinent to AF arrhythmogenesis are still unidentified. The discovery of these missing pathways has the potential to lead to therapeutic breakthroughs. Endocrine dysfunction is well-recognized to lead to AF. In this review, we discuss endocrine and cardiocrine signalling systems that directly, or as a consequence of an underlying cardiac pathology, contribute to AF pathogenesis. More specifically, we consider the roles of products from the hypothalamic-pituitary axis, the adrenal glands, adipose tissue, the renin–angiotensin system, atrial cardiomyocytes, and the thyroid gland in controlling atrial electrical and structural properties. The influence of endocrine/paracrine dysfunction on AF risk and mechanisms is evaluated and discussed. We focus on the most recent findings and reflect on the potential of translating them into clinical application.

The influence of growth hormone therapy on the cardiovascular system in Turner syndrome

Short stature, ovarian dysgenesis, infertility, and cardiovascular malformations are classic features in Turner syndrome (TS), but the phenotypical spectrum is wide. Through early diagnosis and appropriate treatment, TS patients have a chance to achieve satisfactory adult height and sexual development. The doses of recombinant growth hormone (rGH) used are usually higher than the substitution dose. The safety aspects of this therapy are very important, especially in terms of the cardiovascular system. The presented study aimed to analyze how the rGH therapy may influence the cardiovascular system in TS based on current literature data. We conducted a systematic search for studies related to TS, cardiovascular system, and rGH therapy. The results show that rGH seems to have a positive effect on lipid parameters, reducing the risk of ischemic disease. It is additionally optimized by estradiol therapy. Although rGH may increase insulin resistance, the metabolic derangement is rare, probably due to lower fat content and an increase in lean body mass. Several studies showed that rGH treatment could cause aorta widening or increase the aorta growth rate. IGF-1 can be independently associated with increased aortic diameters. The studies analyzing the impact of GH on blood pressure show conflicting data. The proper cardiovascular imaging before and during rGH treatment and detecting the known risk factors for aorta dissection in every individual is very important. The long-term effects of growth hormone treatment on the heart and arteries are still not available and clearly estimated and have to be monitored in the future.

The Biology of Physiological Health

The ability to maintain health, or recover to a healthy state after disease, is an active process involving distinct adaptation mechanisms coordinating interactions between all physiological systems of an organism. Studies over the past several decades have assumed the mechanisms of health and disease are essentially inter-changeable, focusing on the elucidation of the mechanisms of disease pathogenesis to enhance health, treat disease, and increase healthspan. Here, I propose that the evolved mechanisms of health are distinct from disease pathogenesis mechanisms and suggest that we develop an understanding of the biology of physiological health. In this Perspective, I provide a definition of, a conceptual framework for, and proposed mechanisms of physiological health to complement our understanding of disease and its treatment.

Anabolism to Catabolism: Serologic Clues to Nutritional Status in Heart Failure

PURPOSE OF REVIEW

Malnutrition, sarcopenia, and cachexia are areas of increasing interest in the management of patients with heart failure (HF). This review aims to examine the serological markers useful in guiding the physician in identification of these patients.

RECENT FINDINGS

Traditional nutritional biomarkers including albumin/prealbumin, iron, and vitamin D deficiencies predict poor prognosis in malnutrition and HF. Novel biomarkers including ghrelin, myostatin, C-terminal agrin fragment, and adiponectin have been identified as possible substrates and/or therapeutic targets in cardiac patients with sarcopenia and cachexia, though clinical trial data is limited to date. Increased focus on nutritional deficiency syndromes in heart failure has led to the use of established markers of malnutrition as well as the identification of novel biomarkers in the management of these patients, though to date, their usage has been confined to the academic domain and further research is required to establish their role in the clinical setting.

Left Heart Dysfunction in Acromegaly Revealed by Novel Echocardiographic Methods

Background: Acromegaly is a rare disease that requires modern treatment to decrease the risk of mortality, mainly from vascular diseases. Identifying acromegalic patients with increased cardiovascular risk is challenging. Speckle-tracking echocardiography (STE) is a modern, well-validated, and reproducible method of assessing left ventricular longitudinal deformation and providing a sensitive assessment of myocardial contractility. We hypothesized that STE may be useful in evaluating subclinical dysfunction of the left heart in acromegalic patients, especially when a left ventricle (LV) assessment is completed with STE of the left atrium (LA). Purpose: To assess the diagnostic value of speckle-tracking echocardiography in identifying the occurrence of LV and LA functional impairment in patients with acromegaly, in comparison to patients without this rare pituitary disease. Methods: Echocardiographic assessments of LV and LA function using the new STE method were performed in 60 subjects: 30 acromegalic (ACRO group) patients and a CONTROL group with 30 patients matched in terms of age, gender, systolic/diastolic pressure, and history of hypertension for at least 12 months. Results: The ACRO group, compared to the CONTROL group, presented: (1) higher left ventricular mass (left ventricular mass index: 132 vs. 108 g/m², p < 0.001) and, in consequence, more frequent LV hypertrophy (80.0 vs. 53.3%; p = 0.028); (2) impaired LV systolic function measured by both left ventricular ejection fraction (LVEF) (63.4 vs. 66.9%, p < 0.001) and global longitudinal strain (GLS) (-18.1 vs. -19.4%, p = 0.023); (3) greater LA anteroposterior diameter (40.3 vs. 36.9 mm, p = 0.003) and indexed left atrial volume (37.9 vs. 27.6 ml/m², p < 0.001); and (4) impaired echocardiographic strain parameters corresponding with LA function. Conclusions: Acromegaly, even in young patients with good blood pressure control, may be associated with left ventricular hypertrophy and subclinical impairment of the left ventricular and left atrial mechanical function, which may be identified by speckle-tracking echocardiography. Further research in this area is necessary to clarify the prognostic value of these phenomena.

Tissue-Specific GHR Knockout Mice: An Updated Review

Growth hormone (GH) signaling plays a key role in mediating growth, development, metabolism, and lifespan regulation. However, the mechanisms of longevity regulation at the cellular and molecular level are still not well-understood. An important area in the field of GH research is in the development of advanced transgenic systems for conditional expression of GH signaling in a cell type- or tissue-specific manner. There have been many recent studies conducted to examine the effects of tissue-specific GHR disruption. This review updates our previous discussions on this topic and summarizes recent data on the newly-made tissue-specific GHR-KO mice including intestinal epithelial cells, bone, hematopoietic stem cells, cardiac myocytes, and specific brain regions. The data from these new genetically-engineered mice have a significant impact on our understanding of the local GH signaling function.

Useful applications of growth factors for cardiovascular regenerative medicine

Novel advances for cardiovascular diseases (CVDs) include regenerative approaches for fibrosis, hypertrophy, and neoangiogenesis. Studies indicate that growth factor (GF) signaling could promote heart repair since most of the evidence is derived from preclinical models. Observational studies have evaluated GF serum/plasma levels as feasible biomarkers for risk stratification of CVDs. Noteworthy, two clinical interventional published studies showed that the administration of growth factors (GFs) induced beneficial effect on left ventricular ejection fraction (LVEF), myocardial perfusion, end-systolic volume index (ESVI). To date, large scale ongoing studies are in Phase I-II and mostly focussed on intramyocardial (IM), intracoronary (IC) or intravenous (IV) administration of vascular endothelial growth factor (VEGF) and fibroblast growth factor-23 (FGF-23) which result in the most investigated GFs in the last 10 years. Future data of ongoing randomized controlled studies will be crucial in understanding whether GF-based protocols could be in a concrete way effective in the clinical setting.

Molecular Mechanisms of Cardiac Remodeling and Regeneration in Physical Exercise

Regular physical activity with aerobic and muscle-strengthening training protects against the occurrence and progression of cardiovascular disease and can improve cardiac function in heart failure patients. In the past decade significant advances have been made in identifying mechanisms of cardiomyocyte re-programming and renewal including an enhanced exercise-induced proliferational capacity of cardiomyocytes and its progenitor cells. Various intracellular mechanisms mediating these positive effects on cardiac function have been found in animal models of exercise and will be highlighted in this review. 1) activation of extracellular and intracellular signaling pathways including phosphatidylinositol 3 phosphate kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR), EGFR/JNK/SP-1, nitric oxide (NO)-signaling, and extracellular vesicles; 2) gene expression modulation via microRNAs (miR), in particular via miR-17-3p and miR-222; and 3) modulation of cardiac cellular metabolism and mitochondrial adaption. Understanding the cellular mechanisms, which generate an exercise-induced cardioprotective cellular phenotype with physiological hypertrophy and enhanced proliferational capacity may give rise to novel therapeutic targets. These may open up innovative strategies to preserve cardiac function after myocardial injury as well as in aged cardiac tissue.

Acromegaly and Heart Failure

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 in untreated and uncontrolled patients. Additional relevant cardiovascular complications are represented by arterial hypertension, valvulopathies, arrhythmias, and vascular endothelial dysfunction, which, together with the respiratory and metabolic complications, contribute to the development of cardiac disease and the increase cardiovascular risk in acromegaly. Disease duration plays a pivotal role in the determination of acromegalic cardiomyopathy. The main functional disturbance in acromegalic cardiomyopathy is the diastolic dysfunction, observed in 11% to 58% of patients, it is usually mild, without clinical consequence, and the progression to systolic dysfunction is generally uncommon, not seen or observed in less than 3% of the patients. Consequently, the presence of overt CHF is rare in acromegaly, ranging between 1 and 4%, in patients with untreated and uncontrolled disease. Control of acromegaly, induced by either pituitary surgery or medical therapy improves cardiac structure and performance, limiting the progression of acromegaly cardiomyopathy to CHF. However, when CHF is associated with dilative cardiomyopathy, it is generally not reversible, despite the treatment of the acromegaly.

Insulin-Like Growth Factor 1 in the Cardiovascular System

Non-communicable diseases, such as cardiovascular diseases, are the leading cause of mortality worldwide. For this reason, a tremendous effort is being made worldwide to effectively circumvent these afflictions, where insulin-like growth factor 1 (IGF1) is being proposed both as a marker and as a central cornerstone in these diseases, making it an interesting molecule to focus on. Firstly, at the initiation of metabolic deregulation by overfeeding, IGF1 is decreased/inhibited. Secondly, such deficiency seems to be intimately related to the onset of MetS and establishment of vascular derangements leading to atherosclerosis and finally playing a definitive part in cerebrovascular and myocardial accidents, where IGF1 deficiency seems to render these organs vulnerable to oxidative and apoptotic/necrotic damage. Several human cohort correlations together with basic/translational experimental data seem to confirm deep IGF1 implication, albeit with controversy, which might, in part, be given by experimental design leading to blurred result interpretation.

Alteration in cardiac PI3K/Akt/mTOR and ERK signaling pathways with the use of growth hormone and swimming, and the roles of miR21 and miR133

Athletes misuse recombinant human growth hormone (r-hGH) to enhance their performance. Although r-hGH is known to increase cardiac hypertrophy, the underlying molecular mechanism remains unclear. The aim of the present study was to investigate the role of r-hGH in cardiac intracellular signaling pathways and of miR-21 and miR-133 expression in rat hearts during exercise. A total of 36 adult male Sprague-Dawley rats were divided into sedentary control (SC, n=9), swimming exercise (SE, n=8), r-hGH (GH, n=10) and swimming exercise plus r-hGH (SE-GH, n=9) groups. The exercise groups completed a 1-h swimming exercise 5 times a week for 8 weeks. Subcutaneous r-hGH was administered as 0.3 mg/kg/day. Phosphoinositide-3-kinase (PI3K), serine/threonine protein kinase 1 (AKT1), extracellular signal-regulated kinase (ERK), microRNA (miR)-21 and miR-133 expression was evaluated in ventricular muscle by real-time quantitative polymerase chain reaction. Protein expression of PI3K, AKT1, ERK and mechanistic target of rapamycin (mTOR) was also assessed by immunohistochemistry. Statistical differences were analyzed by two-way ANOVA. PI3K and AKT1 expression and the gene and protein levels was notably increased in the SE-GH group compared with in SC ventricular tissues (P<0.05). mTOR protein expression was higher in the GH, SE and SE-GH groups compared with in the SC group (P<0.05, <0.05 and <0.001, respectively). ERK gene/protein expression was similar across all groups. miR-21 and miR-133 levels in ventricular muscle were higher in the SE and GH groups than those in the SC group. In summary, growth hormone application coupled with swimming exercise appeared to affect the PI3K/AKT/mTOR signaling pathway in the left ventricular tissue of rats; however, ERK signaling pathway appeared inactive in physiological left ventricular hypertrophy caused by swimming and GH administration over 8 weeks. Furthermore, GH treatment resulted in increased miR-21 and miR-133 expression. Future study by our group will aim to assess the effects of higher dose GH treatment.

Cardiometabolic Biomarkers and Their Temporal Patterns Predict Poor Outcome in Chronic Heart Failure (Bio-SHiFT Study)

PURPOSE

Multiple hormonal and metabolic alterations occur in chronic heart failure (CHF), but their proper monitoring during clinically silent progression of CHF remains challenging. Hence, our objective was to explore whether temporal patterns of six emerging cardiometabolic biomarkers predict future adverse clinical events in stable patients with CHF.

METHODS

In 263 patients with CHF, we determined the risk of a composite end point of heart failure hospitalization, cardiac death, left ventricular assist device implantation, and heart transplantation in relation to serially assessed blood biomarker levels and slopes (i.e., rate of biomarker change per year). During 2.2 years of follow-up, we repeatedly measured IGF binding proteins 1, 2, and 7 (IGFBP-1, IGFBP-2, IGFBP-7), adipose fatty acid binding protein 4 (FABP-4), resistin, and chemerin (567 samples in total).

RESULTS

Serially measured IGFBP-1, IGFBP-2, IGFBP-7, and FABP-4 levels predicted the end point [univariable hazard ratio (95% CI) per 1-SD increase: 3.34 (2.43 to 4.87), 2.86 (2.10 to 3.92), 2.45 (1.91 to 3.13), and 2.46 (1.88 to 3.24), respectively]. Independently of the biomarkers' levels, their slopes were also strong clinical predictors [per 0.1-SD increase: 1.20 (1.11 to 1.31), 1.27 (1.14 to 1.45), 1.23 (1.11 to 1.37), and 1.27 (1.12 to 1.48)]. All associations persisted after multivariable adjustment for patient baseline characteristics, baseline N-terminal pro-hormone brain natriuretic peptide and cardiac troponin T, and pharmacological treatment during follow-up.

MAIN CONCLUSIONS

The temporal patterns of IGFBP-1, IGFBP-2, IGFBP-7, and adipose FABP-4 predict adverse clinical outcomes during outpatient follow-up of patients with CHF and may be clinically relevant as they could help detect more aggressive CHF forms and assess patient prognosis, as well as ultimately aid in designing more effective biomarker-guided therapy.

Retrospective Analysis of Endocrine Dysfunctions in a Population of Adult Polytransfused Patients: Correlation of GH-IGF1 Axis Alteration with Cardiac Performance

Endocrine complications of haemochromatosis and heart failure mostly affect morbidity and mortality in polytransfused patients. This study analyzes endocrine dysfunctions and the impact of GH-IGF-1 axis alteration on cardiac performance in a population of 31 patients. A retrospective study on 31 Caucasian polytransfused outpatients, 27 adults and 4 pediatric, residing in Apulia, Italy, followed from 2005 to 2016, was conducted. Patients underwent basal and dynamic hormonal evaluation. GHRH plus arginine test was performed in 21 patients (19 adults and 2 children). Among them, 9 patients were affected by left ventricle diastolic dysfunction and/or atrial or ventricular dilatation (HD group) and 12 patients did not have cardiovascular disease (non-HD group). Twenty-nine out of 31 patients (94%) had at least one endocrinopathy. We found severe or mild GH deficit (GHD) in all HD patients versus 3 patients in the non-HD group (p=0.001). Mean IGF-1 levels were significantly lower in the HD group than in non-HD subjects (53±30 versus 122±91 μg/L, p=0.04). Our study confirms the need to perform a dynamic evaluation of the GH-IGF1 axis in polytransfused patients, especially when heart dysfunction emerges. An intervention study with GH replacement therapy in a larger randomized adult population will clarify the role of GH/IGF axis on cardiovascular outcomes in this patient population.

Impaired repletion of intramyocellular lipids in patients with growth hormone deficiency after a bout of aerobic exercise

BACKGROUND

Ectopic lipids such as intramyocellular lipids (IMCL) are depleted by exercise and repleted by diet, whereas intrahepatocellular lipids (IHCL) are increased immediately after exercise. So far, it is unclear how ectopic lipids behave 24 h after exercise and whether the lack of growth hormone (GH) significantly affects ectopic lipids 24 h after exercise.

METHODS

Seven male patients with growth hormone deficiency (GHD) and seven sedentary male control subjects (CS) were included. VO_2max was assessed by spiroergometry; visceral and subcutaneous fat by whole body MRI. ¹H-MR-spectroscopy was performed in M. vastus intermedius and in the liver before and after 2 h of exercise at 50% VO_2max and 24 h thereafter, while diet and physical activity were standardized.

RESULTS

Sedentary male subjects (7 GHD, 7 CS) were recruited. Age, BMI, waist circumference, visceral and subcutaneous fat mass was not significantly different between GHD and CS. VO_2max was significantly lower in GHD vs. CS. IMCL were diminished through aerobic exercise in both groups: (-11.5 ± 21.9% in CS; -8.9% ±19.1% in GHD) and restored after 24 h in CS (-5.5 ± 26.6% compared to baseline) but not in GHD (-17.9 ± 15.3%). IHCL increased immediately after exercise and decreased to baseline within 24 h.

CONCLUSION

These findings suggest that GHD may affect repletion of IMCL 24 h after aerobic exercise.

IGF-1-Overexpressing Mesenchymal Stem/Stromal Cells Promote Immunomodulatory and Proregenerative Effects in Chronic Experimental Chagas Disease

Mesenchymal stem/stromal cells (MSCs) have been investigated for the treatment of diseases that affect the cardiovascular system, including Chagas disease. MSCs are able to promote their beneficial actions through the secretion of proregenerative and immunomodulatory factors, including insulin-like growth factor-1 (IGF-1), which has proregenerative actions in the heart and skeletal muscle. Here, we evaluated the therapeutic potential of IGF-1-overexpressing MSCs (MSC_IGF-1) in a mouse model of chronic Chagas disease. C57BL/6 mice were infected with Colombian strain Trypanosoma cruzi and treated with MSCs, MSC_IGF-1, or vehicle (saline) six months after infection. RT-qPCR analysis confirmed the presence of transplanted cells in both the heart and skeletal muscle tissues. Transplantation of either MSCs or MSC_IGF-1 reduced the number of inflammatory cells in the heart when compared to saline controls. Moreover, treatment with MSCs or MSC_IGF-1 significantly reduced TNF-α, but only MSC treatment reduced IFN-γ production compared to the saline group. Skeletal muscle sections of both MSC- and MSC_IGF-1-treated mice showed a reduction in fibrosis compared to saline controls. Importantly, the myofiber area was reduced in T. cruzi-infected mice, and this was recovered after treatment with MSC_IGF-1. Gene expression analysis in the skeletal muscle showed a higher expression of pro- and anti-inflammatory molecules in MSC_IGF-1-treated mice compared to MSCs alone, which significantly reduced the expression of TNF-α and IL-1β. In conclusion, our results indicate the therapeutic potential of MSC_IGF-1, with combined immunomodulatory and proregenerative actions to the cardiac and skeletal muscles.

Acromegalic cardiomyopathy: Epidemiology, diagnosis, and management

Acromegalic cardiomyopathy is the leading cause of morbidity and all-cause mortality in patients with acromegaly. Though acromegaly is a rare condition, the associated derangements are vast and severe. Stemming from an increase in circulating growth hormone (GH) and insulin-like growth factor-1 levels (IGF-1), acromegalic cardiomyopathy results in pathological changes in myocyte growth and structure, cardiac contractility, and vascular function. These molecular changes manifest commonly as biventricular hypertrophy, diastolic and systolic dysfunction, and valvular regurgitation. Early recognition of the condition is paramount, though the insidious progression of the disease commonly results in a late diagnosis. Biochemical testing, based on IGF-1 measurements, is the gold standard of diagnosis. Management should be centered on normalizing serum levels of both IGF-1 and GH. Transsphenoidal resection remains the most cost-effective and permanent treatment for acromegaly, though medical therapy possesses benefit for those who are not surgical candidates. Ultimately, achieving control of hormone levels results in a severe reduction in mortality rate, underscoring the importance of early recognition and treatment.

Cardioprotective effect of ghrelin against myocardial infarction-induced left ventricular injury via inhibition of SOCS3 and activation of JAK2/STAT3 signaling

The molecular mechanisms through which ghrelin exerts its cardioprotective effects during cardiac remodeling post-myocardial infarction (MI) are poorly understood. The aim of this study was to investigate whether the cardioprotection mechanisms are mediated by modulation of JAK/STAT signaling and what triggers this modulation. Rats were divided into six groups (n = 12/group): control, sham, sham + ghrelin (100 µg/kg, s.c., daily, starting 1 day post-MI), MI, MI+ ghrelin, and MI+ ghrelin+ AG490, a potent JAK2 inhibitor (5 mg/kg, i.p., daily). All treatments were administered for 3 weeks. Administration of ghrelin to MI rats improved left ventricle (LV) architecture and restored cardiac contraction. In remote non-infarcted areas of MI rats, ghrelin reduced cardiac inflammation and lipid peroxidation and enhanced antioxidant enzymatic activity. In addition, independent of the growth factor/insulin growth factor-1 (GF/IGF-1) axis, ghrelin significantly increased the phosphorylation of JAK2 and Tyr702 and Ser727 residues of STAT3 and inhibited the phosphorylation of JAK1 and Tyr701 and Ser727 residues of STAT1, simultaneously increasing the expression of BCL-2 and decreasing in the expression of BAX, cleaved CASP3, and FAS. This effect coincided with decreased expression of SOCS3. All these beneficial effects of ghrelin, except its inhibitory action on IL-6 expression, were partially and significantly abolished by the co-administration of AG490. In conclusion, the cardioprotective effect of ghrelin against MI-induced LV injury is exerted via activation of JAK2/STAT3 signaling and inhibition of STAT1 signaling. These effects were independent of the GF/IGF-1 axis and could be partially mediated via inhibition of cardiac IL-6.

Growth Hormone (GH) and Cardiovascular System

This review describes the positive effects of growth hormone (GH) on the cardiovascular system. We analyze why the vascular endothelium is a real internal secretion gland, whose inflammation is the first step for developing atherosclerosis, as well as the mechanisms by which GH acts on vessels improving oxidative stress imbalance and endothelial dysfunction. We also report how GH acts on coronary arterial disease and heart failure, and on peripheral arterial disease, inducing a neovascularization process that finally increases flow in ischemic tissues. We include some preliminary data from a trial in which GH or placebo is given to elderly people suffering from critical limb ischemia, showing some of the benefits of the hormone on plasma markers of inflammation, and the safety of GH administration during short periods of time, even in diabetic patients. We also analyze how Klotho is strongly related to GH, inducing, after being released from the damaged vascular endothelium, the pituitary secretion of GH, most likely to repair the injury in the ischemic tissues. We also show how GH can help during wound healing by increasing the blood flow and some neurotrophic and growth factors. In summary, we postulate that short-term GH administration could be useful to treat cardiovascular diseases.

Short-Term Evaluation of Left Ventricular Mass and Function in Children With Growth Hormone Deficiency After Replacement Treatment

Background: Our study was designed to assess the effects of GHD on nutritional and metabolic parameters, brain natriuretic peptide (BNP) levels, and left ventricular mass (LVM) in prepubertal children and after short-term GH replacement therapy. Materials and Methods: This prospective study enrolled 81 children. We compared 40 GHD children (16 males and 24 females) to 41 healthy children (control group) (18 males and 23 females). All subjects were at Tanner Stage I (aged 7-11 years). At the baseline, a blood sample was drawn and echocardiographic images were obtained. These tests were repeated on the GHD subjects after 6 months of GH replacement therapy. Body surface, weight, size, blood pressure, heart rate, glucose, insulin, HOMA-IR, HOMA-β, QUICKI, cholesterol, HDLc, LDLc, triglycerides, IGF1, and IGFBP3 were measured. Indexed LVM, diastolic and systolic diameter (dD-sD), diastolic and systolic LV function, isovolumic relaxation time, right ventricle function, and BNP levels were obtained through echocardiography. These parameters were correlated to growth factors. Data were analyzed using Student's t-test or U-Mann-Whitney-test and Pearson's correlation, considering p < 0.05 to be significant. Results: Indexed LVM was smaller in GHD patients than in controls, whereas diastolic and systolic functions, BNP, metabolic, and nutritional profiles were similar. After treatment, nutritional and metabolic profiles significantly improved, though diastolic and systolic functions did not seem to have changed. There was a significant increase in LVM. Indexed LVM was similar to that of controls. Significant correlations were obtained between LVM-IGF1 and sD-IGFBP3. Conclusions: GHD in childhood is associated with a lower indexed LVM. In the short-term, GH increases the indexed LVM, while maintaining normal systolic and diastolic functions, BNP, and an improved lipid profile.

The Heart of the Matter: Cardiac Manifestations of Endocrine Disease

Endocrine disorders manifest as a disturbance in the milieu of multiple organ systems. The cardiovascular system may be directly affected or alter its function to maintain the state of homeostasis. In this article, we aim to review the pathophysiology, diagnosis, clinical features and management of cardiac manifestations of various endocrine disorders.

Refractory hypotension induced by Sheehan syndrome with pituitary crisis: A case report

The present study reported on an unusual case of refractory hypotension induced by Sheehan syndrome with pituitary crisis and explored the causes and treatment of hypotension in hypopiptuitarism. Refractory hypotension is a rare and severe complication of longstanding hypopituitarism induced by Sheehan syndrome with pituitary crisis. A 48-year-old Chinese woman with pituitary crisis due to Sheehan syndrome developed refractory hypotension and received longstanding vasopressor blood pressure support and hormone replacement therapy. Besides normalized blood pressure, echocardiography over 3 months revealed partial reversibility of her cardiac function with hormone replacement therapy. Consistent numerous studies reviewed, hormone replacement therapy may improve cardiac function in patients with cardiomyopathy linked to Sheehan syndrome. A retrospective study of 77 cases with hypopituitarism encountered at Qilu Hospital of Shandong University (Jinan, China) was also performed and the incidence rate of hypotension was analyzed, revealing that the present case was the first of refractory hypotension induced by Sheehan syndrome with pituitary crisis at this institution in 16 years.

Fetal origins of adult cardiac disease: a novel approach to prevent fetal growth restriction induced cardiac dysfunction using insulin like growth factor

BACKGROUND

Fetal growth restriction (FGR) is a risk factor for adult cardiovascular disease. Intraplacental gene transfer of human insulin-like growth factor-1 (IGF-1) corrects birth weight in our mouse model of FGR. This study addresses long term effects of FGR on cardiac function and the potential preventive effect of IGF-1.

STUDY DESIGN

Laparotomy was performed on pregnant C57BL/6J mice at embryonic day 18 and pups were divided into three groups: Sham operated; FGR (induced by mesenteric uterine artery ligation); treatment (intraplacental injection of IGF-1 after uterine artery ligation). Pups were followed until 32 wk of life. Transthoracic echocardiography was performed starting at 12 wk.

RESULTS

Systolic cardiac function was significantly impaired in the FGR group with reduced fractional shortening compared with sham and treatment group starting at week 12 of life (20 ± 4 vs. 31 ± 5 vs. 32 ± 5, respectively, n = 12 for each group; P < 0.001) with no difference between the sham and treatment groups.

CONCLUSION

Intraplacental gene transfer of IGF-1 prevents FGR induced cardiac dysfunction. This suggests that in utero therapy may positively impact cardiac remodeling and prevent adult cardiovascular disease.

Ghrelin and the Cardiovascular System

Ghrelin is a small peptide released primarily from the stomach. It is a potent stimulator of growth hormone secretion from the pituitary gland and is well known for its regulation of metabolism and appetite. There is also a strong relationship between ghrelin and the cardiovascular system. Ghrelin receptors are present throughout the heart and vasculature and have been linked with molecular pathways, including, but not limited to, the regulation of intracellular calcium concentration, inhibition of proapoptotic cascades, and protection against oxidative damage. Ghrelin shows robust cardioprotective effects including enhancing endothelial and vascular function, preventing atherosclerosis, inhibiting sympathetic drive, and decreasing blood pressure. After myocardial infarction, exogenous administration of ghrelin preserves cardiac function, reduces the incidence of fatal arrhythmias, and attenuates apoptosis and ventricular remodeling, leading to improvements in heart failure. It ameliorates cachexia in end-stage congestive heart failure patients and has shown clinical benefit in pulmonary hypertension. Nonetheless, since ghrelin's discovery is relatively recent, there remains a substantial amount of research needed to fully understand its clinical significance in cardiovascular disease.

Multiple Effects of Growth Hormone in the Body: Is it Really the Hormone for Growth?

In this review, we analyze the effects of growth hormone on a number of tissues and organs and its putative role in the longitudinal growth of an organism. We conclude that the hormone plays a very important role in maintaining the homogeneity of tissues and organs during the normal development of the human body or after an injury. Its effects on growth do not seem to take place during the fetal period or during the early infancy and are mediated by insulin-like growth factor I (IGF-I) during childhood and puberty. In turn, IGF-I transcription is dependent on an adequate GH secretion, and in many tissues, it occurs independent of GH. We propose that GH may be a prohormone, rather than a hormone, since in many tissues and organs, it is proteolytically cleaved in a tissue-specific manner giving origin to shorter GH forms whose activity is still unknown.

IGF-1 and NT-proBNP in a black and white population: The SABPA study

BACKGROUND

Black populations exhibit lower concentrations of the cardioprotective peptide, insulin-like growth factor-1 (IGF-1), and are more prone to develop hypertensive heart disease than whites. We therefore determined whether lower IGF-1 in black individuals relates to a marker of cardiac overload and systolic dysfunction, namely N-terminal prohormone B-type natriuretic peptide (NT-proBNP).

MATERIALS AND METHODS

We included 160 black and 195 white nondiabetic South African men and women (aged 44·4 ± 9·81 years) and measured ambulatory blood pressure, NT-proBNP, IGF-1 and insulin-like growth factor-binding protein-3 (IGFBP-3).

RESULTS

Although the black group presented elevated ambulatory blood pressure accompanied by lower IGF-1 compared to the white group (all P < 0·001), we found similar NT-proBNP concentrations (P = 0·72). Furthermore, in blacks we found a link between NT-proBNP and systolic blood pressure (SBP) (R(2) = 0·37; β = 0·28; P < 0·001), but not with IGF-1. In the white group, NT-proBNP was inversely associated with IGF-1 (R(2) = 0·39; β = -0·22; P < 0·001) after adjusting for covariates and potential confounders. As IGF-1 is attenuated in diabetes, we added the initially excluded patients with diabetes (n = 38), and the aforementioned associations remained robust.

CONCLUSION

Contrary to the white group, we found no association between NT-proBNP and IGF-1 in black adults. Our findings suggest that SBP and other factors may play a greater contributory role in cardiac pathology in blacks.

Cardiac-Specific Disruption of GH Receptor Alters Glucose Homeostasis While Maintaining Normal Cardiac Performance in Adult Male Mice

GH is considered necessary for the proper development and maintenance of several tissues, including the heart. Studies conducted in both GH receptor null and bovine GH transgenic mice have demonstrated specific cardiac structural and functional changes. In each of these mouse lines, however, GH-induced signaling is altered systemically, being decreased in GH receptor null mice and increased in bovine GH transgenic mice. Therefore, to clarify the direct effects GH has on cardiac tissue, we developed a tamoxifen-inducible, cardiac-specific GHR disrupted (iC-GHRKO) mouse line. Cardiac GH receptor was disrupted in 4-month-old iC-GHRKO mice to avoid developmental effects due to perinatal GHR gene disruption. Surprisingly, iC-GHRKO mice showed no difference vs controls in baseline or postdobutamine stress test echocardiography measurements, nor did iC-GHRKO mice show differences in longitudinal systolic blood pressure measurements. Interestingly, iC-GHRKO mice had decreased fat mass and improved insulin sensitivity at 6.5 months of age. By 12.5 months of age, however, iC-GHRKO mice no longer had significant decreases in fat mass and had developed glucose intolerance and insulin resistance. Furthermore, investigation via immunoblot analysis demonstrated that iC-GHRKO mice had appreciably decreased insulin stimulated Akt phosphorylation, specifically in heart and liver, but not in epididymal white adipose tissue. These changes were accompanied by a decrease in circulating IGF-1 levels in 12.5-month-old iC-GHRKO mice. These data indicate that whereas the disruption of cardiomyocyte GH-induced signaling in adult mice does not affect cardiac function, it does play a role in systemic glucose homeostasis, in part through modulation of circulating IGF-1.

Gastrointestinal and Liver Issues in Heart Failure

Heart failure affects ≈23 million people worldwide and continues to have a high mortality despite advancements in modern pharmacotherapy and device therapy. HF is a complex clinical syndrome that can result in the impairment of endocrine, hematologic, musculoskeletal, renal, respiratory, peripheral vascular, hepatic, and gastrointestinal systems. Although gastrointestinal involvement and hepatic involvement are common in HF and are associated with increased morbidity and mortality, their bidirectional association with HF progression remains poorly fathomed. The current understanding of multiple mechanisms, including proinflammatory cytokine milieu, hormonal imbalance, and anabolic/catabolic imbalance, has been used to explain the relationship between the gut and HF and has been the basis for many novel therapeutic strategies. However, the failure of these novel therapies such as anti–tumor necrosis factor-α has resulted in further complexity. In this review, we describe the involvement of the gastrointestinal and liver systems within the HF syndrome, their pathophysiological mechanisms, and their clinical consequences.

Advanced Strategies for End-Stage Heart Failure: Combining Regenerative Approaches with LVAD, a New Horizon?

Despite the improved treatment of cardiovascular diseases, the population with end-stage heart failure (HF) is progressively growing. The scarcity of the gold standard therapy, heart transplantation, demands novel therapeutic approaches. For patients awaiting transplantation, ventricular-assist devices have been of great benefit on survival. To allow explantation of the assist device and obviate heart transplantation, sufficient and durable myocardial recovery is necessary. However, explant rates so far are low. Combining mechanical circulatory support with regenerative therapies such as cell (-based) therapy and biomaterials might give rise to improved long-term results. Although synergistic effects are suggested with mechanical support and stem cell therapy, evidence in both preclinical and clinical setting is lacking. This review focuses on advanced and innovative strategies for the treatment of end-stage HF and furthermore appraises clinical experience with combined strategies.