title: Discordant HIF1A mRNA levels and oxidative stress in placental shares of monochorionic twins with selective intra-uterine growth restriction.
abstract: BACKGROUND
  Oxidative stress is a key factor in the pathogenesis of intra-uterine growth restriction in singleton. However, its role in selective intra-uterine growth restriction (sIUGR) in monochorionic twins (MCT) is still unknown. This study explored the characteristics of oxidative stresses in the placenta shares of MCT and analyzed their possible connections with sIUGR.
  
  
  METHODS
  The placental levels of hypoxia inducible factor-1α gene (HIF1A)mRNA, malondialdehyde (MDA), and 8-hydroxydeoxyguanosine (8-OHdG) were evaluated in normal MCT (Group A) and sIUGR MCT (Group B). The results were compared between the placental shares of the larger twins (A1/B1) and smaller twins (A2/B2).
  
  
  RESULTS
  Placental HIF1A mRNA level significantly increased in Group B. Particularly, HIF1A mRNA level was elevated in the placenta share of the growth-restricted fetus (B2) than the co-twin (B1) (P = 0.036). More discordant HIF1A mRNA level was detected in Group B than Group A with larger inter-twin difference (P = 0.021). The levels of MDA and 8-OHdG were significantly higher in B2 than B1 in sIUGR MCT (P < 0.05). Both the inter-twin differences of MDA and 8-OHdG were also significantly larger in Group B (P < 0.05), indicating that discordant oxidative stress existed in the placental shares of sIUGR pregnancies. Finally, MDA concentration was found inversely correlated with neonatal birth weight, in both sIUGR (r = -0.650, P = 0.022) and normal MCT (r = -0.632, P = 0.027) pregnancies.
  
  
  CONCLUSIONS
  The elevation of HIF1A mRNA, and MDA/8-OHdG levels in placenta shares of sIUGR MCT suggests that oxidative stress may be involved in the pathogenesis of sIUGR.
authors.affiliation: Department of Obstetrics, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong, China; Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510080, China.
authors.forename: G-L
authors.initials: GL
authors.lastname: Zhang
authors.affiliation: Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510080, China.
authors.forename: Z-M
authors.initials: ZM
authors.lastname: He
authors.affiliation: Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510080, China.
authors.forename: X-M
authors.initials: XM
authors.lastname: Shi
authors.affiliation: Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510080, China.
authors.forename: C-Y
authors.initials: CY
authors.lastname: Gou
authors.affiliation: Department of Obstetrics and Gynecology, The Sixth Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510655, China. Electronic address: gy_sums@hotmail.com.
authors.forename: Y
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Fetal Medicine Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong 510080, China. Electronic address: fang_qun@163.com.
authors.forename: Q
authors.initials: Q
authors.lastname: Fang
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D001724:Birth Weight; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004200:Diseases in Twins / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005317:Fetal Growth Retardation / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D015227:Lipid Peroxidation; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress; D010920:Placenta / Q000378:metabolism* / Q000473:pathology; D011247:Pregnancy; D059285:Pregnancy, Twin / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D008315:Malondialdehyde; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine
keywords: Monochorionic twins; Oxidative stress; Placenta; Selective intra-uterine growth restriction