Related Experiment Videos
Endogenous digoxin-like factor in neonates: effect of age and relation to serum bilirubin levels
1Department of Pediatrics, Meir Hospital, Sapir Medical Center, Kfar Saba, Israel.
Insights
Serum levels of endogenous digoxin-like immunoreactive factors (DLIF) are highest in newborns and decrease with age. Higher DLIF levels correlate with increased bilirubin, suggesting a role in neonatal jaundice.
Area of Science:
- Neonatal Physiology
- Biochemistry
Background:
- Endogenous digoxin-like immunoreactive factors (DLIF) are present in newborn serum and urine.
- Previous studies indicate DLIF may be relevant in the neonatal period.
Purpose of the Study:
- To assess the impact of age on serum DLIF levels in healthy newborns.
- To investigate the relationship between serum DLIF and bilirubin concentrations in jaundiced neonates.
Main Methods:
- Serum samples from 66 healthy full-term newborns were collected at birth and during the first two months.
- DLIF concentrations were measured over time.
- Correlation between DLIF and bilirubin was analyzed in 23 jaundiced newborns.
Main Results:
- DLIF concentrations were highest at birth (0.73 ng/ml) and decreased progressively with age, becoming undetectable after 45 days.
- A significant positive correlation was observed between serum bilirubin and DLIF levels in jaundiced newborns.
- DLIF levels at day 1, day 3, day 5, day 11, and days 15-30 were 0.45, 0.26, 0.19, 0.17, and 0.11 ng/ml, respectively.
Conclusions:
- Serum DLIF levels decline significantly after birth in healthy term infants.
- DLIF may impede bilirubin excretion in neonates, potentially by inhibiting Na-K ATPase activity.
- These findings suggest a role for DLIF in neonatal hyperbilirubinemia.
Abstract:
Endogenous digoxin-like immunoreactive factor(s) (DLIF) have been found in serum and urine of newborn infants, including those born prematurely. We assessed the effect of age on serum levels of DLIF in 73 samples obtained from 66 healthy full term newborn infants at birth and during the first two months of life. DLIF concentrations were highest at birth and fell progressively with age. In cord blood, DLIF levels were 0.73 +/- 0.35 ng/ml (mean +/- SD). DLIF concentrations were 0.45 +/- 0.11 ng/ml on day 1, 0.26 +/- 0.08 ng/ml on day 3, 0.19 +/- 0.07 ng/ml on day 5, 0.17 +/- 0.09 ng/ml on day 11, 0.11 +/- 0.02 ng/ml on days 15-30, and not detectable after 45 days of life. We also studied the relation between serum levels of DLIF and bilirubin in 23 jaundiced newborns between 3-5 days of life. We found a highly significant positive correlation between serum bilirubin concentrations and DLIF. These findings support the assumption that DLIF plays a role in impeding bilirubin excretion in the neonatal period, perhaps by inhibiting the activity of (Na-K)ATPase.