Early biomarkers identified in a rat model of a healthier phenotype based on early postnatal dietary intervention may predict the response to an obesogenic environment in adulthood

Moderate maternal calorie restriction during lactation in rats provides certain protection against obesity in adult offspring. Hence, we used this model with 20% calorie restriction to identify early changes at the gene expression level in key tissues involved in energy homeostasis, as well as to assess whether they are maintained in adulthood, to consider them as potential biomarkers of metabolic health. Offspring of control and 20% calorie-restricted dams during lactation (CR) were followed. Animals were studied at weaning and at 6 months old under normal-fat (NF) diet and after being moved to a high-fat (HF) diet for the last 2 months. Adult CR animals showed lower body weight, decreased hepatic lipids and improved circulating parameters vs. controls. At weaning, CR pups, in retroperitoneal white adipose tissue (rWAT), displayed lower messenger RNA (mRNA) levels of lipogenesis-related genes and higher mRNA levels of genes related with lipolysis and insulin signaling vs. controls. CR animals also showed lower hepatic mRNA levels of the lipogenesis-related gene sterol regulatory element-binding protein 1c (SREBP1c) and higher mRNA levels of carnitine palmitoyltransferase 1 isoform a, adipose triglyceride lipase and long-form leptin receptor (ObRb). Some of these changes were sustained in adulthood under HF diet, and mRNA levels of IRS1 (rWAT) and of ObRb and SREBP1c (liver) in adult animals correlated with hepatic lipids and circulating parameters. In conclusion, the protective effects of moderate calorie restriction during lactation on offspring metabolic health are reflected in early changes at gene expression level in key tissues. Among them, transcript levels of IRS1 (rWAT) and of ObRb and SREBP1c (liver) emerge as particularly interesting as potential transcript-based biomarkers of metabolic health.