The role of interleukin-33 and its receptor ST2 in human pregnancy. (7th June 2011)

• Record Type: Journal Article
• Authors: McKenna, L A; Jordan, F; Brown, E A; Huda, S S; Mackay, V A; Miller, A M; Freeman, D J
• Is Part Of: Archives of disease in childhood. Volume 96(2011)Supplement 1
• Page Start: Fa98
• Page End: Fa98
• Publication Date: 2011-06-07
• Subjects: Infants -- Diseases -- Periodicals; Newborn infants -- Diseases -- Periodicals; Fetus -- Diseases -- Periodicals; 618.920105
• DOI: 10.1136/adc.2011.300163.5
• Languages: English
• ISSNs: 1359-2998

Abstract

Abstract : Introduction: Placental cytokine expression differs between normal and complicated pregnancy (Williams et al, 2009). Interleukin-33 (IL-33) and its receptor ST2 are involved in lipid delivery in maternal adipose tissue. Our study hypothesised that IL-33 is an important pregnancy cytokine which influences early placental development and/or regulates fetal lipid supply. Methods: Maternal plasma, adipose tissue and placentas were sampled at caesarean section. Non-pregnant plasma was also analysed. IL-33 and ST2 messenger RNA (mRNA) expression was quantified by real-time PCR. IL-33 and ST2 protein was localised in healthy and complicated placentas by immunohistochemistry and plasma soluble ST2 (sST2) measured by ELISA. Results: Third trimester pregnant women had significantly higher plasma sST2 than non-pregnant women (p<0.001). Placental IL-33 and ST2 expression increases across gestation. In early pregnancy, IL-33 and ST2 are localised to syncytiotrophoblasts and later to the syncytium. Placental ST2 expression correlated with plasma sST2 levels in healthy pregnancy (r=0.36; p=0.02). IL-33 mRNA expression was 62% lower in IUGR placentas (p=0.003) and ST2 mRNA expression was 207% higher in pre-eclamptic placentas (p=0.002). In pre-eclamptic pregnancies, visceral adipose tissue ST2 expression was also 80% higher (p=0.02). In complicated pregnancy, IL-33 and ST2 staining appeared generally reduced. Conclusions: The IL-33/ST2 signalling pathway plays a role healthy pregnancy. The placenta is responsible for increased circulating sST2 in pregnancy. In IUGR, placental IL-33 is down-regulated, which may reduce circulating maternal triglycerides. In pre-eclampsia, placental ST2 expression increases and may promote increased lipolytic activity. Third trimester plasma sST2 levels did not differ between healthy and complicated pregnancy, indicating ST2 retention for IL-33 signalling.