Presented at the Neonatal Society 2015 Spring Meeting.
Whistler J, Mostyn A, Hyde MJ
School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Leicestershire, LE12 5RD
Neonatal Medicine, Imperial College London, Chelsea and Westminster Campus, 369 Fulham Road, London, SW10 9NH
Background: The occurrence of pre-labour Caesarean section (CS) delivery is increasing, despite limited research on the effects on neonatal metabolism. We have previously described differences in adipose tissue in offspring delivered by CS delivery; and attributed these to the loss of the intrapartum cortisol surge (1). We now explore the impact of route of delivery on skeletal muscle (SM) metabolic pathways in porcine neonates. We hypothesise that CS delivery will reduce SM metabolic processes which are essential for neonatal survival.
Methods: Four pregnant sows were randomly allocated to CS at 112 days gestation (~115 days is full term) or spontaneous vaginal delivery (VD). Both CS (n=4) and VD (n=5) offspring were fed a sow milk replacer. At 7 days of age piglets were humanely euthanased and SM sampled. Gene expression was assessed using real time PCR, tissue glycogen, lipid and protein were measured by biochemical assay. All animal work had full local ethical and national Home Office approval; further information on the methods are described by Hyde et al (2). Data was analysed using SPSS and Arraymining.net.
Results: 11β-Hydroxysteroid dehydrogenase type 2 (CS=0.89±0.02, VD=1±0.02; p=0.03) and insulin-like growth factor 1 (CS=0.95±0.02, VD=1±0.01; p=0.03) expression was reduced in the CS group while pyruvate dehydrogenase kinase 4 was increased (CS=1.19±0.06, VD=1±0.02; p=0.03). A significant reduction in glycogen was observed in the VD group (CS=67.8±0.2, VD=32.4±0.3; p=0.03), however, tissue lipid and protein concentrations were similar. Serum hormone and metabolite concentrations were made available via MJH and significant reductions in glucose, lactate and triglyceride were identified. A significant negative relationship between IGF1 expression and fractional growth rate was observed in the CS group only (R2=0.91, P=0.05). Cluster analysis segregated the data into two independent clusters: one single cluster included all VD offspring and all the CS offspring in the second cluster.
Conclusion: Despite the small animal numbers, this study demonstrates striking differences in crucial metabolic pathways, particularly glycogenolysis, between Caesarean section and vaginally delivered neonatal offspring. The long-term impacts of these changes remain to be elucidated.
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1. Thickett A, et al.Proc Nutr Soc. 2011;70:E28
2. Hyde MJ, et al.Clin Sci. 2009;118:47