Determinants of intrahepatocellular lipid (IHCL) in healthy term infants

Abstract

Background: In adults intrahepatocellular lipid (IHCL) is a strong correlate of insulin resistance and other components of the metabolic syndrome. Knowledge about IHCL in healthy term infants is very limited. Aim: The aim of this study was to describe the variation in IHCL in healthy term neonates and identify determinants of deposition. My secondary aim was to explore the relationship between IHCL and body adiposity. Methods: With Research Ethics approval and informed written parent consent I employed Magnetic Resonance Imaging and Hepatic Spectroscopy during natural sleep in healthy term neonates. Using SPSS 17.0 birth weight, gestational size, gender, mode of delivery, maternal BMI and diabetes were analysed singly in relation to IHCL (expressed as lipid CH2/water ratio) and performing analysis of covariance. Results: I have studied 52 male and 56 female infants, born by vaginal delivery (VD, n=72), in-labour Caesarean Section (CS, n=18) and pre-labour CS (n=18). Maternal Body Mass Index (BMI) ranged from 17 to 41. IHCL ranged from 0 to 17.27, median 0.48. Postnatal age was positively correlated with IHCL. There was a trend toward higher IHCL in males. In infants born by pre-labour CS, there was a statistically significant positive effect of maternal BMI on IHCL, with no effect in the other two groups. Birth weight, gestational size and maternal diabetes did not show any effect on IHCL. There was a positive correlation between IHCL and total adipose tissue (AT), superficial and deep subcutaneous AT, after adjusting for birth weight and gender. Conclusion: IHCL content in healthy term babies is variable and appears to increase with postnatal age. A new suggestion is that VD may activate pathways protecting against IHCL accumulation that is driven by increasing maternal BMI. The strong correlation between deep subcutaneous AT and IHCL points to the potential role in metabolic programming.