RESUMEN
BACKGROUND: Since the discovery more than half a century ago, cell-free DNA (cfDNA) has become an attractive objective in multiple diagnostic, prognostic, and monitoring settings. However, despite the increasing number of cfDNA applications in liquid biopsies, we still lack a comprehensive understanding of the nature of cfDNA including optimal assessment. In the presented study, we continued testing and validation of common techniques for cfDNA extraction and quantification (qRT-PCR or droplet digital PCR) of nuclear- and mitochondrial cfDNA (ncfDNA and mtcfDNA) in blood, using a piglet model of perinatal asphyxia to determine potential temporal and quantitative changes at the levels of cfDNA. METHODS AND RESULTS: Newborn piglets (n = 19) were either exposed to hypoxia (n = 11) or were part of the sham-operated control group (n = 8). Blood samples were collected at baseline (= start) and at the end of hypoxia or at 40-45 min for the sham-operated control group. Applying the qRT-PCR method, ncfDNA concentrations in piglets exposed to hypoxia revealed an increasing trend from 7.1 ng/ml to 9.5 ng/ml for HK2 (hexokinase 2) and from 4.6 ng/ml to 7.9 ng/ml for ß-globulin, respectively, whereas the control animals showed a more balanced profile. Furthermore, median levels of mtcfDNA were much higher in comparison to ncfDNA, but without significant differences between intervention versus the control group. CONCLUSIONS: Both, qRT-PCR and the droplet digital PCR technique identified overall similar patterns for the concentration changes of cfDNA; but, the more sensitive digital PCR methodology might be required to identify minimal responses.
Asunto(s)
Ácidos Nucleicos Libres de Células , Animales , Porcinos , Ácidos Nucleicos Libres de Células/genética , Asfixia , Reacción en Cadena de la Polimerasa/métodos , Biopsia Líquida , HipoxiaRESUMEN
OBJECTIVES: To investigate association between latency after preterm premature rupture of membranes (PPROM) and perinatal outcomes at moderately and late preterm gestation. METHODS: National perinatal registry-based cohort study using data for the period 2013-2018. Singleton pregnancies with non-malformed fetuses in cephalic presentation complicated by PPROM at 32+0-36+6 weeks were included. Associations between latency period and perinatal mortality, neonatal respiratory distress syndrome (RDS), early onset neonatal infection (EONI), and cesarean section were assessed using multiple logistic regression, adjusting for potential confounders (labor induction, maternal body-mass-index, maternal age, antenatal corticosteroids, and small-for-gestational-age). p<0.05 was considered statistically significant. RESULTS: Of 3,017 pregnancies included, 365 (12.1%) had PPROM at 32+0-33+6 weeks and 2,652 (87.9%) at 34+0-36+6 weeks. Among all cases, 2,540 (84%) had latency <24 h (group A), 305 (10%) 24-47 h (group B), and 172 (6%) ≥48 h (group C). Longer latency was associated with higher incidence of EONI (adjusted odds ratio [aOR] 1.350; 95% confidence interval [CI] 0.900-2.026 for group B and aOR 2.500; 95% CI 1.599-3.911 for group C) and higher rate of caesarean section (aOR 2.465; 95% CI 1.763-3.447 for group B and aOR 1.854; 95% CI 1.172-2.932 for group C). Longer latency was not associated with rates of RDS (aOR 1.160; 95% CI 0.670-2.007 for group B and aOR 0.917; 95% CI 0.428-1.966 for group C). CONCLUSIONS: In moderately to late PPROM, increased latency is associated with higher risk of EONI and cesarean section with no reduction in RDS.