title: Overnutrition during lactation leads to impairment in insulin signaling, up-regulation of GLUT1 and increased mitochondrial carbohydrate oxidation in heart of weaned mice.
abstract: Several studies have demonstrated that overnutrition during early postnatal period can increase the long-term risk of developing obesity and cardiac disorders, yet the short-term effects of postnatal overfeeding in cardiac metabolism remains unknown. The aim of our study was to investigate the cardiac metabolism of weaned mice submitted to overnutrition during lactation, particularly as to mitochondrial function, substrate preference and insulin signaling. Postnatal overfeeding was induced by litter size reduction in mice at postnatal day 3. At 21 days of age (weaning), mice in the overfed group (OG) presented biometric and biochemical parameters of obesity, including increased body weight, visceral fat, liver weight and increased left ventricle weight/tibia length ratio; indicating cardiac hypertrophy, hyperglycemia, hyperinsulinemia and increased liver glycogen content compared to control group. In the heart, we detected impaired insulin signaling, mainly due to decreased IRβ, pTyr-IRS1, PI3K, GLUT4 and pAkt/Akt and increased PTP1B, GLUT1 and pAMPKα/AMPKα content. Activities of lactate dehydrogenase and citrate synthase were increased, accompanied by enhanced carbohydrate oxidation, as observed by high-resolution respirometry. Moreover, OG hearts had lower CPT1, PPARα and increased UCP2 mRNA expression, associated with increased oxidative stress (4-HNE content), BAX/BCL2 ratio and cardiac fibrosis. Ultrastructural analysis of OG hearts demonstrated mild mitochondrial damage without alterations in OXPHOS complexes. In conclusion, overnutrition during early life induces short-term metabolic disturbances, impairment in heart insulin signaling, up-regulates GLUT-1 and switch cardiac fuel preference in juvenile mice.
authors.affiliation: Laboratory of Nutrition Physiology and Development, Department of Physiological Sciences, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Amélia F
authors.initials: AF
authors.lastname: Bernardo
authors.affiliation: Laboratory of Cell Culture, Department of Histology and Embryology, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Erika
authors.initials: E
authors.lastname: Cortez
authors.affiliation: Laboratory of Nutrition Physiology and Development, Department of Physiological Sciences, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Fabiana A
authors.initials: FA
authors.lastname: Neves
authors.affiliation: Laboratory of Nutrition Physiology and Development, Department of Physiological Sciences, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Anatalia K G
authors.initials: AK
authors.lastname: Vieira
authors.affiliation: Laboratory of Nutrition Physiology and Development, Department of Physiological Sciences, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Vivian de M
authors.initials: Vde M
authors.lastname: Soares
authors.affiliation: Laboratory of Nutrition Physiology and Development, Department of Physiological Sciences, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Alessandra C de S
authors.initials: AC
authors.lastname: Rodrigues-Cunha
authors.affiliation: Laboratory of Cell Culture, Department of Histology and Embryology, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Daniela C
authors.initials: DC
authors.lastname: Andrade
authors.affiliation: Laboratory of Cell Culture, Department of Histology and Embryology, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Alessandra A
authors.initials: AA
authors.lastname: Thole
authors.affiliation: School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.
authors.forename: Daniele
authors.initials: D
authors.lastname: Gabriel-Costa
authors.affiliation: School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Brum
authors.affiliation: Laboratory of Nutrition Physiology and Development, Department of Physiological Sciences, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Aníbal S
authors.initials: AS
authors.lastname: Moura
authors.affiliation: Laboratory of Nutrition Physiology and Development, Department of Physiological Sciences, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: ericagarciasouza@gmail.com.
authors.forename: Érica P
authors.initials: ÉP
authors.lastname: Garcia-Souza
mesh_terms: D000818:Animals; D050260:Carbohydrate Metabolism; D051272:Glucose Transporter Type 1 / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D007774:Lactation; D051379:Mice; D008929:Mitochondria, Heart / Q000378:metabolism*; D044343:Overnutrition; D010084:Oxidation-Reduction; D015398:Signal Transduction; D015854:Up-Regulation
chemical_list: D051272:Glucose Transporter Type 1; D007328:Insulin; C495678:Slc2a1 protein, mouse
keywords: Cardiac insulin signaling; Cardiac metabolism; Mitochondrial function; Obesity; Overnutrition