Apples and oranges: Differential transcriptomic and protein response between cord and peripheral blood in neonates
Cord blood is used frequently as a correlate for peripheral blood in neonates despite its exposure to perinatal stress responses and possibly other environmental factors. Unlike peripheral blood, cord blood is easily accessible, making it more convenient to use. It is commonly thought that umbilical cord blood and peripheral blood have the same cellular composition and are functionally the same from an immunological standpoint. However, there is minimal data to confirm that this alternative approach is valid.
Whole blood samples (400-500µL) from cord and peripheral blood will be collected in micro-containers containing EDTA (ethylenediaminetetraacetic acid) during routine resuscitation from 20 preterm and 20 term neonates, followed by immediate RNA stabilization in PaxGene™ reagent. Peripheral blood samples will be collected from the same newborn with need for immediate venous access for either antibiotics (suspected early onset sepsis) or prostaglandin infusion (congenital heart disease) or other clinical reasons. RNA will be amplified using the Nugen Ovation Pico WTA System V2 (Nugen Technologies) and hybridized labeled cDNA targets to Affymetrix GeneChip® GGh3 Transcriptome Array per standard protocols. Plasma will be isolated from whole blood immediately and stored for subsequent batch processing at − 80 °C.
The transcriptomic and protein response within cord blood activates during labor and is thought to be notably different in response when compared to responses in peripheral blood. Therefore, limitations could be present when using cord blood as a correlate to peripheral blood.