Brain lactate in preterm and growth–retarded neonates

Abstract

Glucose is the predominant cerebral energy source under physiological conditions, although other substrates may support cerebral metabolism. The present study was undertaken to determine if lactate is present in the immature human brain, and if so, whether or not concentrations of lactate differ between small-for-gestational-age and appropriate-for-gestational-age infants. Thirty stable, healthy infants with normal brains were investigated. As the only nutrient, all received milk enterally prior to the investigation, which was carried out without sedation. Mean gestational age was 35 completed weeks (range 28-41 weeks) and mean birth weight was 2170 g (range 855-4100 g). Proton nuclear magnetic resonance spectra from the striatal region were obtained while the infants were sleeping quietly. Lactate was present in all 10 preterm small-for-gestational-age and 10 of 13 preterm appropriate-for-gestational-age infants, and the concentration was inversely related to postmenstrual age (p < 0.002). In addition, lactate increased with the degree of growth retardation (p < 0.01). At present the significance of lactate is unclear. Lactate may be produced locally or in peripheral tissues, and may support brain metabolism.

Brain Metabolite Levels Assessed by Lactate-Edited MR Spectroscopy in Premature Neonates with and without Pentobarbital Sedation

“…2 Indeed, there is evidence that lactate is used as a metabolic fuel in the immature central nervous system. 23 Anaerobic glycolysis may, therefore, be an important mechanism to satisfy the energy requirements of the immature brain. The impact of barbiturates on brain metabolic rate and glucose metabolism has been studied extensively.…”

Lactate, N‐acetylaspartate, choline and creatine concentrations, and spin‐spin relaxation in thalamic and occipito‐parietal regions of developing human brain

“…undetectable in normal brain at term, but was found in preterm and small-for-gestational-age (SGA) infants (31). Cerebral Lac has often been detected in birth-asphyxiated infants: elevated Lac is thought to predict unfavorable outcome (2,32 (16,29,32,(34)(35)(36)(37)(38)(39).…”

Proton MR Spectroscopy in Infants with Cerebral Energy Deficiency due to Hypoxia and Metabolic Disorders

“…The presence of detectable Lac signals has been reported for very young infants (18,25). This signal may reflect a normal metabolic state in the immature brain.…”