Hyperglycaemic Preterm Babies Have Sex Differences in Insulin Secretion

Area of Science:

• Neonatalogy
• Endocrinology
• Metabolic Research

Background:

• Hyperglycaemia is a frequent complication in premature infants, contributing to mortality and morbidity.
• The exact causes of hyperglycaemia in neonates are not fully understood.
• Plasma C-peptide levels are used in adults to estimate insulin secretion due to predictable clearance.

Purpose of the Study:

• To quantify insulin secretion in hyperglycaemic preterm infants using plasma C-peptide concentrations.
• To investigate the relationship between blood glucose levels and endogenous insulin production in neonates.
• To explore potential sex-based differences in insulin secretion among preterm infants.

Main Methods:

• Retrospective analysis of 41 very preterm infants (median gestational age 27.2 weeks).
• Infants were enrolled in a trial for tight glycemic control upon developing hyperglycaemia (two consecutive blood glucose concentrations > 8.5 mmol·l⁻¹).
• Insulin secretion was calculated using a two-compartment C-peptide kinetic model with steady-state analysis.

Main Results:

• Blood glucose, insulin, C-peptide, and insulin secretion were higher at randomization compared to 1-2 weeks post-randomization.
• Female infants exhibited significantly higher insulin secretion (11.7 mU·l⁻¹·kg⁻¹·min⁻¹) than male infants (4.7 mU·l⁻¹·kg⁻¹·min⁻¹).
• Insulin secretion was lower during exogenous insulin administration compared to periods without it.

Conclusions:

• Endogenous insulin secretion in preterm infants is responsive to blood glucose levels.
• Female preterm infants demonstrate higher insulin secretion than males, independent of blood glucose and insulin concentrations.
• C-peptide analysis provides a valuable method for assessing insulin secretion in neonatal hyperglycaemia.