ESPE Abstracts

Introduction: Maternal caloric restriction during gestation leads to offspring’s metabolic programming through epigenetic changes, which increase the risk of developing cardiovascular diseases in adulthood.

Objectives: To study in a swine animal model: i) DNA methylation changes associated with caloric restriction during gestation in the adipose tissue of the offspring; and ii) the reversibility of these changes by metformin treatment.

Materials and methods: Commercial production sows (Landrace×Duroc) were fed either a standard or a calorie restricted diet (30% reduction compared to standard) throughout gestation, to deliver control (C) or growth-restricted (R) piglets, respectively. Piglets from each group (n=32) were treated with 50 mg/kg/day oral metformin (n=16) or placebo (n=16) across lactation. At sacrifice (weaning, age 28 days) piglets were weighed, adipose tissue was collected and metabolic markers were measured in serum. Adipose tissue methylome was analysed by RRBS (Reduced Representation Bisulphite Sequencing; n=8 per subgroup of gestation and pharmacological treatment). As for the study of differential methylation, annotated CpG sites were analysed, SNPs were filtered and a methylation difference >15% and a q-value <0.05 were considered relevant for further analyses.

Results: R piglets showed similar weights than C piglets at weaning, together with a partly altered metabolic profile [higher CRP and lower circulating adiponectin (P<0.01)]. In retroperitoneal adipose tissue, maternal restriction triggered hypermethylation of 163 CpG and hypomethylation of 109 CpG, all these lists being enriched in CpGs corresponding to genes that regulate growth and metabolism (FDR<10). Piglets receiving metformin showed methylation differences compared to those receiving placebo in 221 CpG sites (88 hypermethylated and 133 hypomethylated). The CpG sites that were associated with FASN, PRKCZ and NELFB showed differential methylation in both situations but in opposite directions: FASN and PRKCZ were hypermethylated upon gestational restriction and hypomethylated in metformin treated piglets; NELFB was hypomethylated upon gestational restriction and hypermethylated during metformin treatment.

Conclusions: Gestational caloric restriction induces changes in the methylome of the offspring’s adipose tissue, including methylation variations in FASN (a key enzyme in fatty acid biosynthesis), PRKCZ (a member of the PKC family of serine/threonine kinases involved in cell proliferation and differentiation) and NELFB (a regulator of the RNA polymerase II involved in embryonic development and homeostasis in adult tissue). Metformin may contribute to reverse the deleterious effects on these genes.