Abstract
Purpose :
Oxytocin (OXT) is a neuropeptide hormone associated with the retina, and may play a critical role in the signaling mechanisms responsible for angiogenesis in health and disease. Our goal is to determine circulating levels of OXT in cord blood samples to understand its role in the development of the eye. We also would like to explore whether the mode of delivery or the presence of labor affects circulating levels of fetal OXT.
Methods :
Cord blood samples are to be collected from 130 infants divided into 3 populations: premature infants (< 28 weeks’ gestation) delivered vaginally, full-term infants (> 37 weeks’ gestation) delivered vaginally, and infants of all gestations delivered by cesarean section. We have conducted a preliminary analysis on adult human plasma with and without supplemented OXT, to identify a method of in vitro OXT extraction. Plasma was separated from whole blood via centrifugation and OXT was isolated using C18 Sep-Pak columns. The concentration of OXT was determined using an OXT ELISA kit (ENZO).
Results :
OXT was extracted from adult plasma in varying concentrations using the ENZO OXT ELISA kit. Concentrations [1,000, 500, 250, 125 and 62.5 pg/ml] of OXT were plotted along a standard curve and evaluated via immunoassay software. We found that human plasma collected from EDTA and heparinized blood samples yielded OXT concentrations of 4.6 and 10.2 pg/ml, respectively. Additionally, human plasma samples were spiked with 1000pg/mL of OXT, revealing a 44% yield following isolation through Sep-Pak columns.
Conclusions :
Our assay shows that circulating OXT can be separated from plasma and studied at varying concentrations. The percent yield of extracted OXT, and the concentrations of OXT resulted from the EDTA and heparinized tubes were less than optimal. This could be attributed to human error, impure OXT supplementation or low-circulating levels of adult human OXT. We have notably characterized a robust OXT assay in human plasma samples irrespective of storage conditions. We hope to further study the expression of OXT in the retinal maturation of preterm infants. We speculate that preterm infants < 28 weeks’ gestation with ROP will have negligible levels of circulating OXT, suggesting OXT may be necessary for normal retinal cell maturation.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.