Effects of inter-twin vascular anastomoses of monochorionic twins with selective intrauterine growth restriction on the contents of placental mitochondria DNA

Yao-Lung Chang,Sheng-Yuan Su,An-Shine Chao,Shuenn-Dyh Chang,Tzu-Hao Wang,Kuan-Ju Chen,Hsiu-Huei Peng

doi:10.1186/s12884-018-1702-8

Abstract

BackgroundPlacental mitochondrial DNA (mtDNA) has been proposed to be an indicator for placental hypoxia. This study was designed to evaluate the effect of vascular anastomoses between monochorionic (MC) twins on placental mtDNA.MethodsIn this study, twin-twin transfusion syndrome (TTTS) treated with laser therapy and MC twins without TTTS (without laser therapy) resulting in two live babies were included in this study. The placental mtDNA fold changes (FC) between the small and large twins were analyzed using real-time quantitative PCR. TTTS twins with selective intrauterine growth restriction (sIUGR) are categorized as group 1, TTTS without sIUGR as group 2, MC twins without TTTS but with sIUGR as group 3, and MC twins without both TTTS and sIUGR as group 4.ResultsThere were seven cases in group 1, eight in group 2, 26 in group 3, and 24 in group 4 cases. The placental mtDNA FC were significantly higher in group 1 (1.57 ± 0.9) compared to that of the group 3 (0.86 ± 0.6).ConclusionIn MC twin pregnancies with sIUGR, the placental mtDNA FC between the small and large twins are different between cases with and without inter-twin anastomoses. These findings suggest that the inter-twin anastomoses in the MC twins with sIUGR may provide rescue perfusion from the appropriate-for-gestational-age twin to the sIUGR one.

Highlights

Placental mitochondrial DNA has been proposed to be an indicator for placental hypoxia
We have previously found that mitochondrial activation in cord blood and the amniocytes of the selective intrauterine growth restriction (sIUGR) fetus in MC twins was likely to be regulated by locally adverse placental conditions resulting in reduced blood flow, rather than genetic factors [16]
There were no statistical differences in maternal age at delivery, gestational age at delivery, birth weight of the smaller twin, birth weight of the larger twin, or birth weight discordance between twin-twin transfusion syndrome (TTTS) and No TTTS twins, in cases with sIUGR or in the cases without sIUGR

Summary

Introduction

Placental mitochondrial DNA (mtDNA) has been proposed to be an indicator for placental hypoxia. This study was designed to evaluate the effect of vascular anastomoses between monochorionic (MC) twins on placental mtDNA. MtDNA typically replicates during every cell cycle; each daughter cell usually maintains a relatively consistent number of copies of mtDNA [4]. MtDNA has been shown to be increased in placental tissues of pregnancies with intrauterine growth restriction (IUGR) [8, 9]. The exact mechanism how the placental mtDNA increase in the case of sIUGR remains unclear, placental mtDNA contents were correlated with low oxygen levels [8]. The copy numbers of mitochondrial DNA were increased by changes affecting fetal growth [10]. Monochorionic (MC) twins, who share identical genetic materials, enable us to study the mechanisms of mtDNA increase in cases of IUGR without confounding effects from genetic factors

Methods

Results

Discussion

Conclusion