Serum digoxin-like immunoreactive factor in children and its relation to sodium metabolism

Area of Science:

• Pediatric Endocrinology
• Cardiovascular Physiology
• Renal Physiology

Background:

• Serum digoxin-like immunoreactive factor (DLIF) is an endogenous substance cross-reacting with digoxin antibodies.
• The physiological role of DLIF, particularly in children without cardiac glycoside treatment, remains unclear.

Purpose of the Study:

• To investigate the presence and potential associations of DLIF with sodium homeostasis and blood pressure in children.
• To explore the relationship between DLIF levels and markers of sodium balance in a pediatric cohort.

Main Methods:

• Fluorescence polarization immunoassay was used to measure DLIF in serum samples from 134 children (aged 5-16 years).
• Serum sodium, urine sodium concentration, fractional sodium excretion, and blood pressure were assessed.
• Statistical analyses were performed to identify correlations between DLIF and physiological parameters.

Main Results:

• DLIF was detected in 50% of children at a mean concentration of 0.16 ng/ml.
• Children with DLIF exhibited significantly lower serum sodium, higher urinary sodium concentration, and higher fractional sodium excretion compared to those without DLIF.
• Inverse correlations were observed between DLIF concentration and serum sodium, urine sodium, 24-h sodium excretion, and both systolic and diastolic blood pressure.

Conclusions:

• Sodium handling appears to differ between children with and without DLIF.
• DLIF may be released in individuals tending towards a negative sodium balance.
• These findings suggest a potential role for DLIF in pediatric sodium homeostasis.