The effect of anti-thrombotic therapy on cell-free DNA release from first- and third-trimester placental explants: insights into the mechanism of non-invasive prenatal test (NIPT) failures

Abstract Objective: Low molecular weight heparins, including enoxaparin, have been associated with increased non-invasive prenatal testing (NIPT) failures due to low fetal fraction of cell-free (cf) DNA. This study investigated the effect of enoxaparin and antiplatelet therapies on placental tissue in vitro, aiming to determine effects on cfDNA release. Method: First- and third-trimester human placental explants were treated with graded concentrations of enoxaparin, aspirin, clopidogrel, prasugrel and ticagrelor. Concentrations of cfDNA in the culture media were quantified and relative differences between treated and control samples were assessed using the Student’s T-test. Expression of apoptosis genes BAX and BCL2 was assessed in placental explants by RT-qPCR. Results: Enoxaparin treatment significantly increased cfDNA release by placental explants (p<0.01). This effect was more pronounced in the first trimester samples. Increase in cfDNA with enoxaparin was not associated with altered expression of apoptosis genes. There was no significant difference in cfDNA release in placental explants cultured with aspirin or newer anti-platelet agents. Conclusions: Our in vitro results suggest that NIPT failures associated with enoxaparin therapy are unlikely to be mediated by reduced placental cfDNA release. Antiplatelet agents do not have a significant impact on cfDNA release or apoptosis.