Determination of Vitamin D-Dependent Coagulation Proteins in the Umbilical Cord Blood of Full Term Infants

Abstract

Vitamin K, which is synthesized in the liver, is vital in the blood coagulation system because the activity of many protein (Factors II, IX,X, and Proteins C and S) in this system are dependent on it. Most infants born to healthy, well nourished mothers will have an adequate store of most vitamins at birth, with the exception of Vitamin K. It has been previously demonstrated that many infants bleed excessively during the first week of life or experience other hemostatic disorders. Many of these problems can be effectively treated with an injection or oral dose of Vitamin K administered soon after birth. The characteristics and functions of these factors have been widely described in normal adults but very little work has been done to determine the protein levels in normal, healthy newborns. This study was designed to determine the normal reference values of these proteins in the umbilical cord blood of full-term infants. Plasma samples were obtained from 45 full-term infants and protein levels were determined by electroimmunoassay. During the course of this study abnormal double-peaks, instead of the normal single peaks, were occasionally encountered on the electrophoresis gels. Discovery of these peaks necessitated the characterization of the proteins that constitute the second peak and the determination of when, why and how often they occur. This study established the normal reference values of Vitamin K-dependent proteins in full-term infants and found them to be significantly lower, as compared to adults. Double-peaks occurred in 13% of the infants and occurred primarily in the plasma of patients that had some clinical disorder. Yet, despite these results no definite correlation can be made between double-peaks and a specific clinical disorder. Our results suggest that significantly lower levels of Vitamin K-dependent, coagulation proteins in full-term infants, as compared to adults, may be due to prematurity of the liver. Although the double-peaks were identified, we were unable to fully characterize the macromolecule constituents. The macromolecule components may be different charges on the same molecule, two species of the same molecule or a denatured molecule.