Relative cardiac expression of growth hormone receptor and insulin-like growth factor-I mRNA in congenital heart disease

Abstract

GH may exert direct growth-promoting and metabolic actions on target tissues, but most of its effects are mediated by circulating (endocrine) or local (auto-/paracrine) IGF-I. The GH/IGF-I system has an important role in cardiac development and in maintaining the structure and function of the heart. A subgroup of children with pronounced heart defects will eventually need transplants, owing to congestive heart failure. Since the symptoms are often severe and may progress while waiting for surgery, it is necessary to develop supportive medical treatment. GH has been proposed as a therapeutic agent in adults with heart failure, but to date studies are lacking on children and more information is necessary. We have examined the expression of IGF-I mRNA and GH-receptor (GH-R) mRNA in children undergoing surgery for congenital heart disease. Eighteen children scheduled for open-heart surgery were included in the study. Right auricular biopsies were taken at the time of venous catheterization preceding cardiac bypass. The specimens were analysed using realtime PCR. We were able to show expression of both IGF-I mRNA and GH-R mRNA in the pediatric heart. The relative expressions were intercorrelated (r=0.75, p<0.001). GH-R mRNA correlated positively to standardized weight (r=0.65, p=0.004), body mass index (BMI) (r=0.59, p=0.01), and standardized BMI (r=0.59, p=0.01). IGF-I mRNA only correlated to BMI (r=0.50, p=0.04). This is the first study displaying cardiac expression of IGF-I mRNA and GH-R mRNA in children with congenital heart disease, although further studies are needed to define a role for GH in the treatment of these patients.

Effect of Lactation on myocardial vulnerability to ischemic insult in rats

“…In addition, initiation and maintenance of lactation involve many hormones such as oxytocin, prolactin, growth hormone, thyroxine, adrenal corticoids, and parathyroid hormone. 30 Cardiac tissue expresses a wide variety of hormone receptors, including receptors for lactogenic hormones, 31,32 and nursing-induced changes in hormonal milieu have been reported to improve the cardiovascular profiles.…”

Neonatal IGF‐1/IGFBP‐1 axis and retinopathy of prematurity are associated with increased blood pressure in preterm children

“…IGF-1 has a wide spectrum of physiological effects such as regulation of cardiac contractility, tissue remodelling, glucose metabolism and vasomotor activity 26 . IGF-1 has anti-apoptotic features and is present in cardiac tissue in children 27 . In young adulthood, former preterm subjects have been shown to have the highest relative mortality rates from cardiovascular-related disorders 28 .…”

Rapid cardiovascular effects of growth hormone treatment in short prepubertal children: impact of treatment duration

“…In animal studies, GH has been shown to be involved in cardiac gene expression and collagen deposition in extracellular matrix . We have previously shown that GH receptor and IGF‐I mRNA are expressed in cardiac biopsies from children . The early increase in septal and posterior wall thickness could be influenced by direct effects of GH on the heart.…”

“…2 We have previously shown that GH receptor and IGF-I mRNA are expressed in cardiac biopsies from children. 33 The early increase in septal and posterior wall thickness could be influenced by direct effects of GH on the heart. Interestingly, at 2 years, the effect on left ventricular diameter, normalized diastolic BP and cardiac index remained but the myocardial thickness returned to baseline values.…”