Developmental Ontogeny of Adipose Cellularity and Gene Expression in the Neonatal Piglet

Abstract

Childhood obesity has reached epidemic proportions and its prevention is a public health priority. Postnatal weight gain may be a determinant for the development of obesity. The piglet is a common preclinical model for the human infant; however, little is known about adipocyte development and lipogenic gene expression in neonatal piglets. Subcutaneous and renal adipose tissue were obtained from sow‐reared piglets (n = 12 female; n = 12 male) at d2, 7, 14 and 21 postpartum. No effect of gender was found, so data were pooled by day. Adipocyte number and size were determined using a Coulter counter and gene expression measured by real‐time PCR. Subcutaneous adipocyte cell number/mg tissue was greater (p<0.05) at d2 than d7, 14 or 21 due to an increase in cell size with age. The smallest sized cells (20–30 μm) represented 72% of adipocytes on d2, but only 21% by d21. Cells sized 50–70 μm increased (p<0.05) from 4% to 32% between d2 and d21. The greatest changes occurred between d2 and d7 postpartum. The mRNA expression of CEBP‐α, C/EBP‐β and LPL in renal adipose tissue increased over time. GLUT‐4 and PPAR‐γ mRNA expression were greater at d21 than d7 and d14. In summary, piglets displayed rapid changes in adipocyte cell size, which was reflected in the pattern of adipogenic and lipogenic gene expression. These findings are similar to the human and emphasizes the utility of the porcine model. Funded by the Illinois Soybean Association.