The possibility of microarray-based analysis using cell-free placental mRNA in maternal plasma

Objective The purpose of this study is to investigate a possibility of overall assessment of cell-free (CF) placental mRNAs in maternal plasma. Methods First, placenta-predominantly expressed transcripts were selected by the analysis of GeneChip using three sets of placental tissues and corresponding maternal blood cells. Subsequently, a custom cDNA array panel of placenta-predominantly expressed transcripts was designed and used to compare the RNA profiles of maternal plasma collected from 12 preeclamptic and 12 uncomplicated pregnancies. Scatter plots for the signal intensities of the comparative cDNA hybridization revealed either unchanged or aberrant patterns. Results We selected top 50 placenta-predominantly expressed transcripts that were >2500 times higher in placental tissues than in corresponding whole blood samples. A custom cDNA array analysis detected the aberrant pattern in five preeclamptic women with severe hypertension but not in seven preeclamptic women with mild hypertension (P < 0.05, Fisher's direct method). The aberrant pattern of above RNA transcripts in maternal plasma was validated by quantitative real-time reverse transcription-polymerase chain reaction. The mean (range) value of coefficient of variations in this custom array quantification was 9.4% (3.0-16.2%). Conclusion Our custom cDNA array is expected to be useful for overall assessment of CF placental mRNAs in maternal plasma in a single experiment. Copyright (C) 2010 John Wiley & Sons, Ltd.