Functional analysis of cell-free RNA using mid-trimester amniotic fluid supernatant in pregnancy with the fetal growth restriction.

The prediction and monitoring of fetal growth restriction (FGR) fetuses has become with the use of ultrasound. However, these tools lack the fundamental evidence for the growth of fetus with FGR excluding pathogenic factors.Amniotic fluid samples were obtained from pregnant women for fetal karyotyping and genetic diagnosis at 16 to 19 weeks of gestation. For this study, 15 FGR and 9 control samples were selected, and cell-free fetal RNA was isolated from each supernatant of the amniotic fluid for microarray analysis.In this study, 411 genes were differentially expressed between the FGR and control group. Of these genes, 316 genes were up-regulated, while 95 genes were down-regulated. In terms of gene ontology, the up-regulated genes were highly related to metabolic process as well as protein synthesis, while the down-regulated genes were related to receptor activity and biological adhesion. In terms of tissue-specific expression, the up-regulated genes were involved in various organs while down-regulated genes were involved only in the brain. In terms of organ-specific expression, many genes were enriched for B-cell lymphoma, pancreas, eye, placenta, epithelium, skin, and muscle. In the functional significance of gene, low-density lipoprotein receptor-related protein 10 (LRP10) was significantly increased (6-fold) and insulin-like growth factor (IGF-2) was dramatically increased (17-fold) in the FGR cases.The results show that the important brain-related genes are predominantly down-regulated in the intrauterine growth restriction fetuses during the second trimester of pregnancy. This study also suggested possible genes related to fetal development such as B-cell lymphoma, LRP10, and IGF-2. To monitor the fetal development, further study may be needed to elucidate the role of the genes identified.