Obesity in mares alters embryo lipid metabolism

Obesity in pregnant mares adversely affects the embryo’s lipid metabolism and this may carry on in the foal.
DrO

Biol Reprod. 2018 Oct 1;99(4):761-772. doi: 10.1093/biolre/ioy107.
Obesity in mares promotes uterine inflammation and alters embryo lipid fingerprints and homeostasis.
Sessions-Bresnahan DR1,2, Heuberger AL3,4, Carnevale EM2.

Author information:
1. Department of Animal Science, Mount Berry, Georgia, USA.
2. Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA.
3. Horticulture and Landscape Architecture, Colorado State University, Fort Collins, Colorado, USA.
4. Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, Colorado, USA.
Abstract

Maternal body composition can be an important determinant for development of obesity and metabolic syndrome in adult offspring. Obesity-related outcomes in offspring may include epigenetic alterations; however, mechanisms of fetal programming remain to be fully elucidated. This study was conducted to determine the impact of maternal obesity in the absence of a high fat diet on equine endometrium and preimplantation embryos. Embryos were collected from normal and obese mares at 8 and 16 days and a uterine biopsy at 16 days (0 day = ovulation). With the exception of 8 day embryos, each sample was divided into two pieces. One piece was analyzed for gene expression markers related to carbohydrate metabolism, lipid homeostasis, inflammation, endoplasmic reticulum stress, oxidative stress, mitochondrial stress, and components of the insulin-like growth factor (IGF) system. The second piece was analyzed for lipid content using matrix-assisted laser desorption/ionization mass spectrometry. Obese mares had elevated concentrations of insulin, leptin, and total cholesterol, and they tended to have increased triglycerides and decreased insulin sensitivity. Embryos from obese mares had altered transcript abundance in genes for inflammation and lipid homeostasis, as well as endoplasmic reticulum, oxidative and mitochondrial stress and altered lipid fingerprints. Endometrium from obese mares had increased expression of inflammatory cytokines, lipid homeostasis regulation, mitochondrial stress, and the IGF2 system. This study demonstrates that increased adiposity in mares alters the uterine environment, transcript abundance of genes for cellular functions, and lipid profiles of embryos. These alterations could affect prenatal programming, with potential long-term effects in offspring.