Insulin-like growth factor-1 receptor expression in the placentae of diabetic and normal pregnancies☆
Accepted 6 April 2006.
Abstract
Background
Septal hypertrophic cardiomyopathy (sHCM) is a characteristic anomaly of the infant of diabetic mother (IDM). Insulin-like growth factor-1 (IGF-1) has been identified as a mediator of tissue overgrowth and we have previously shown that maternal IGF-1 levels were significantly elevated among neonates with asymmetrical sHCM. IGF-1 does not cross the placenta; it exerts physiologic action through binding to the IGF-1 receptor (IGF-1R). Localisation and expression of IGF-1R in term diabetic pregnancies are largely unclear. We have studied IGF-1R in the placentae of diabetic and normal pregnancies and this receptor expression in association with neonates with sHCM.
Methods
IGF-1R localization and expression in the placentae of six diabetic pregnancies associated with neonatal sHCM were compared with six each of randomly selected diabetic and normal pregnancies without neonatal sHCM by immunohistochemistry. The staining for IGF-1R in the deciduas, cytotrophoblasts, syncytiotrophoblasts and villous endothelium for these 18 samples were assessed and scored by two pathologists who were blinded to the respective diagnoses.
Results
Placental IGF-1R staining was negative in the villous endothelium for all three groups. IGF-1R staining was present in deciduas, cytotrophoblasts and syncytiotrophoblasts but the staining was weaker in the entire group of infants with sHCM compared to those without sHCM.
Conclusions
IGF-1R is localized in all cell types of the placenta except in villous endothelium. Weaker placental IGF-1R staining in the placentae of diabetic pregnancies associated with sHCM suggests reduced expression of IGF-1R. This may be a down-regulatory response to elevated maternal IGF with neonatal sHCM outcome.
aDepartment of Pathology, Faculty of Medicine, Hospital Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, 56000 Cheras, Kuala Lumpur, Malaysia
bDepartment of Paediatrics, Faculty of Medicine, Hospital Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
cDepartment of Obstetrics and Gynaecology, Faculty of Medicine, Hospital Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
Corresponding author. Fax: +60 3 91737340.
☆ The results of this study were presented at the 46th annual meeting of the European Society for Pediatric Research (ESPR) held in Siena, Italy on 31 August–3 September 2005, and was published as an abstract in Pediatric Research, August 2005, volume 58(2), page 365.
1 Abdul Rahman Hayati and Fook Choe Cheah contributed equally to the design of the protocol of this study and the writing of this manuscript.
ABSTRACT