Quantitative analysis of DNA levels in maternal plasma in normal and Down syndrome pregnancies

BACKGROUND: We investigated fetal and total DNA levels in maternal plasma in patients bearing fetuses affected with Down syndrome in comparison to controls carrying fetuses with normal karyotype. METHODS: DNA levels in maternal plasma were measured using real-time quantitative PCR using SRY and β-globin genes as markers. Twenty-one pregnant women with a singleton fetus at a gestational age ranging from 15 to 19 weeks recruited before amniocentesis (carried out for reasons including material serum screening and advanced material age), and 16 pregnant women bearing fetuses affected with Down syndrome between 17 to 22 weeks of gestation were involved in the study. RESULTS: The specificity of the system reaches 100% (no Y signal was detected in 14 women pregnant with female fetuses) and the sensitivity 91.7% (SRY amplification in 22 of 24 examined samples). The median fetal DNA levels in women carrying Down syndrome (n=11) and the controls (n=13) were 23.3 (range 0–58.5) genome-equivalents/ml and 24.5 (range 0–47.5) genome-equivalents/ml of maternal plasma, respectively (P = 0.62). The total median DNA levels in pregnancies with Down syndrome and the controls were 10165 (range 615–65000) genome-equivalents/ml and 7330 (range 1300–36750) genome-equivalents/ml, respectively (P = 0.32). The fetal DNA proportion in maternal plasma was 0%-6 % (mean 0.8%) in women carrying Down syndrome and 0%-2.6 % (mean 0.7 %) in the controls, respectively (P=0.86). CONCLUSIONS: Our study revealed no difference in fetal DNA levels and fetal DNA: maternal DNA ratio between the patients carrying Down syndrome fetuses and the controls

Utilization of Benchtop Next Generation Sequencing Platforms Ion Torrent PGM and MiSeq in Noninvasive Prenatal Testing for Chromosome 21 Trisomy and Testing of Impact of In Silico and Physical Size Selection on Its Analytical Performance

OBJECTIVES: The aims of this study were to test the utility of benchtop NGS platforms for NIPT for trisomy 21 using previously published z score calculation methods and to optimize the sample preparation and data analysis with use of in silico and physical size selection methods. METHODS: Samples from 130 pregnant women were analyzed by whole genome sequencing on benchtop NGS systems Ion Torrent PGM and MiSeq. The targeted yield of 3 million raw reads on each platform was used for z score calculation. The impact of in silico and physical size selection on analytical performance of the test was studied. RESULTS: Using a z score value of 3 as the cut-off, 98.11% - 100% (104-106/106) specificity and 100% (24/24) sensitivity and 99.06% - 100% (105-106/106) specificity and 100% (24/24) sensitivity were observed for Ion Torrent PGM and MiSeq, respectively. After in silico based size selection both platforms reached 100% specificity and sensitivity. Following the physical size selection z scores of tested trisomic samples increased significantly-p = 0.0141 and p = 0.025 for Ion Torrent PGM and MiSeq, respectively. CONCLUSIONS: Noninvasive prenatal testing for chromosome 21 trisomy with the utilization of benchtop NGS systems led to results equivalent to previously published studies performed on high-to-ultrahigh throughput NGS systems. The in silico size selection led to higher specificity of the test. Physical size selection performed on isolated DNA led to significant increase in z scores. The observed results could represent a basis for increasing of cost effectiveness of the test and thus help with its penetration worldwide

Syncytiotrophoblast derived extracellular vesicles transfer functional placental miRNAs to primary human endothelial cells

During the pregnancy associated syndrome preeclampsia (PE), there is increased release of placental syncytiotrophoblast extracellular vesicles (STBEVs) and free foetal haemoglobin (HbF) into the maternal circulation. In the present study we investigated the uptake of normal and PE STBEVs by primary human coronary artery endothelial cells (HCAEC) and the effects of free HbF on this uptake. Our results show internalization of STBEVs into primary HCAEC, and transfer of placenta specific miRNAs from STBEVs into the endoplasmic reticulum and mitochondria of these recipient cells. Further, the transferred miRNAs were functional, causing a down regulation of specific target genes, including the PE associated gene fms related tyrosine kinase 1 (FLT1). When co-treating normal STBEVs with HbF, the miRNA deposition is altered from the mitochondria to the ER and the cell membrane becomes ruffled, as was also seen with PE STBEVs. These findings suggest that STBEVs may cause endothelial damage and contribute to the endothelial dysfunction typical for PE. The miRNA mediated effects on gene expression may contribute to the oxidative and endoplasmic reticulum stress described in PE, as well as endothelial reprogramming that may underlay the increased risk of cardiovascular disease reported for women with PE later in life

Special Issue of Pathogenesis of Pregnancy-Related Complications, 2023

This Special Issue mainly focuses on preeclampsia (PE), haemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome, gestational diabetes mellitus (GDM), foetal growth restriction (FGR), small-for-gestational-age foetuses (SGA), miscarriage, stillbirth, first-episode psychosis (FEP) during pregnancy, and pregnancy-related acute kidney injury (PR-AKI) [...