Insulin-like growth factor-1 receptor expression in the placentae of diabetic and normal pregnancies.
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.
Hayati
Abdul Rahman
AR
Department of Pathology, Faculty of Medicine, Hospital Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, 56000 Cheras, Kuala Lumpur, Malaysia.
Cheah
Fook Choe
FC
Tan
Ay Eeng
AE
Tan
Geok Chin
GC
D002312:Cardiomyopathy, Hypertrophic / Q000209:etiology; D002824:Chorionic Villi / Q000378:metabolism / Q000473:pathology; D003656:Decidua / Q000378:metabolism / Q000473:pathology; D016640:Diabetes, Gestational / Q000378:metabolism* / Q000473:pathology; D004727:Endothelium / Q000378:metabolism / Q000473:pathology; D005260:Female; D018149:Glucose Intolerance / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000209:etiology; D010920:Placenta / Q000378:metabolism* / Q000473:pathology; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000378:metabolism* / Q000473:pathology; D017526:Receptor, IGF Type 1 / Q000378:metabolism*; D014327:Trophoblasts / Q000378:metabolism / Q000473:pathology
D017526:Receptor, IGF Type 1