Obesity induced during sexual maturation is linked to LDL-triacylglycerols in Yucatan miniature swine

Abstract

The incidence of childhood obesity is rising dramatically throughout industrialised countries. To evaluate and study the impact of childhood obesity on lipoprotein metabolism, we developed a new animal model of premature obesity. Yucatan mini-pigs aged 4 months were studied over a 12-month period from childhood to adulthood. Animals were divided into two groups: the first group were overfed a Western misbalanced diet; the second group were normally fed a recommended human-type diet. Cholesterol and triacylglycerol concentrations in VLDL-, LDL-and HDL-lipoproteins were followed from baseline to adulthood by fast protein liquid chromatography. At 10 (the end of sexual maturation) and 16 months old (adulthood), liver, visceral and subcutaneous adipose tissues were sampled. Real-time RT-PCR was performed in order to compare apo AI, apo B, apo C-III, PPAR-a, insulin receptor and lipoprotein lipase gene expression between groups and ages. Differences between groups were observed only after sexual maturity. Adult overfed mini-pigs had a higher LDL-cholesterol:HDL-cholesterol ratio (P,0·05; 0·55 (SE 0·06) for overfed v. 0·42 (SE 0·04) for normally fed pigs at the tenth month of the study). In both groups, VLDL-triacylglycerol decreased (P,0·05). VLDL-triacylglycerol evolution in the overfed group was associated with an increase in LDL-triacylglycerol plasma concentrations (P,0·05) after sexual maturation. LDL-triacylglycerol concentration in overfed mini-pigs went from an average of 0·28 mmol/l before sexual maturation to reach an average concentration of 0·56 mmol/l afterwards. This phenomenon has never been observed in similar studies when obesity is induced in adult mini-pigs and may represent a specific hallmark of an obesity induced during sexual maturity.

Intrauterine growth-restricted Yucatan miniature pigs experience early catch-up growth, leading to greater adiposity and impaired lipid metabolism as young adults

“…Similar to other studies in IUGR models (Poore et al 2002;Woods and Weeks 2004), previous data from our mini-pig model showed that IUGR was associated with higher blood pressure and salt sensitivity in early adulthood (Myrie et al 2011;Myrie et al 2012a). Because the pig is one of the most relevant species for modeling lipoprotein metabolism in humans (Larsen et al 2002;Sébert et al 2005;Torres-Rovira et al 2012), the objective of this study was to evaluate the effects of birth weight, as a proxy for IUGR, on lipid metabolism and endothelial function as indicators of cardiovascular disease risk in a Yucatan miniature pig model.…”

The young göttingen minipig as a model of childhood and adolescent obesity: Influence of diet and gender

“…In this study, feeding a HED with no extra cholesterol added led to moderate increases in TG, TC, and HDL‐C, but did not affect HLD‐C ratio. The diet‐induced changes in plasma lipids were present both before and after sexual maturity, which is interesting, since another study with young male Yucatan minipigs failed to show similar effects despite a comparable increase in BW (31).…”

“…The changes in glucose and lipid metabolism were apparent already after a few weeks of diet feeding, indicating that the recent change from a low energy diet to a high energy diet in itself was sufficient to shift the metabolism independent of vast changes in body fat measures. It is thus possible to acutely induce metabolic impairments in juvenile growing Göttingen minipigs using only moderate dietary intervention, which is in contrast to what has been observed in young Yucatan minipigs (31,36). Surprisingly, the metabolic parameters did not seem to deteriorate further with prolonged diet feeding, despite significant increases in all body fat measures.…”

The Young Göttingen Minipig as a Model of Childhood and Adolescent Obesity: Influence of Diet and Gender

“…The changes in glucose and lipid metabolism were apparent already after a few weeks of diet feeding, indicating that the recent change from a low energy diet to a high energy diet in itself was sufficient to shift the metabolism independent of vast changes in body fat measures. It is thus possible to acutely induce metabolic impairments in juvenile growing G€ ottingen minipigs using only moderate dietary intervention, which is in contrast to what has been observed in young Yucatan minipigs (31,36). Surprisingly, the metabolic parameters did not seem to deteriorate further with prolonged diet feeding, despite significant increases in all body fat measures.…”