The developmental transition of epicardial, paracardial and omental adipose tissue during early life in the sheep (1160.7)

Study objective: This study focused on the transition of epicardial, paracardial and omental fat during early postnatal life using analysis of gene expression. Methods: Sheep were euthanased for adipose tissue sampling at 1, 7 and 28 days of age (n=4 per time point) under UK Home Office Approval. Paracardial adipose tissue was sampled at all ages, whereas epicardial and omental adipose tissues were only present at 7 and 28 days. RNA was extracted and gene expression analysed by qRT‐PCR. Data was analysed using one‐way ANOVA or unpaired t‐Test. Results: With increasing age, the white fat markers leptin and RIP140 mRNA expression increased in all depots studied. PPAR gamma, involved in adipocyte differentiation, also increased with age. Conversely, uncoupling protein (UCP)1 mRNA abundance decreased with age. Putative mRNA markers of brown (lhx8) and beige (tmem26) adipose tissue in rodents were below the limits of detection in all fat depots studied. Conclusions : This study suggests a brown to white fat transformation with increased adipocyte differentiation in all depots studied, irrespective of a fetal (e.g. paracardial) or postnatal (e.g. omental) origin.