Correlations between Digoxin-Like Immunoreactivity and Electrolyte Values in Urinary Samples of Newborns

Abstract

Elevated levels of a group of substances with digoxin-like immunoreactivity (DLIS) are present in biological fluids of newborns. These endogenous substances could also have the biological properties of cardiac glycosides, such as natriuretic and vasoconstrictor activity. Therefore, DLIS could be involved in electrolyte and volume regulation in infants. We measured DLIS, electrolyte (Na⁺, K⁺, Cl^––) and creatinine concentrations in 157 urine samples collected from full-term and preterm infants, with the aim to establish if a correlation exists between the urinary DLIS levels and the respective values of these electrolytes. Significant and positive correlations were found between the urinary concentrations of DLIS and electrolytes. In addition, electrolyte values correlated significantly between themselves. DLIS, K⁺ and Cl^–– values correlated positively with urinary creatinine concentrations (n = 142). A significant multiple correlation was found among DLIS concentrations and creatinine and Cl^–– values. We also studied the DLIS concentrations in serum samples collected at birth in peripheral blood of the mothers and in umbilical cord and gastric aspirate of 5 full-term infants. We observed that DLIS values in newborns are significantly higher than the respective values of the mothers. In conclusion, our data do not demonstrate a clear relationship between DLIS and electrolyte concentrations in urine samples of newborns. Further investigations are necessary to elucidate the biochemical and physiological properties of DLIS.

Urinary Excretion of Endogenous Ouabain-Like Substance in Furosemide-Treated Neonates: Its Relation to Renal Excretory Pattern and Endocrine Factors

“…With [21] have already demonstrated that creatinine concentration correlated significantly with EOLS in 142 urine samples collected from preterm and full-term neonates.…”

“…Studies in the perinatal period have re vealed tissue distribution of EOLS with the highest content in the fetal/neonatal adrenals followed by the gut and the brain [13,14] and there have been reports indicating that plas ma levels and urinary excretion of EOLS inversely correlate with gestational and post natal ages [15][16][17][18], Moreover, significant pos itive correlation has been found between neo natal EOLS and fractional sodium excretion implying that EOLS might be involved in sodium and volume regulation during the ear ly postnatal life [19][20][21].…”

Role of Digoxin-Like Immunoreactive Substance in the Pathogenesis of Transient Tachypnea of Newborn

“…Plasma DLIS levels were related with creatinine levels in adult [16], pediatric [43], and neonatal studies [44]. However, no correlation was found between the DLIS and creatinine levels of adult cases with renal insufficiency [45].…”