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Perdomo L.,Complutense University of Madrid | Perdomo L.,Health Research Institute of San Carlos Clinic Hospital IdISSC | Perdomo L.,CIBER ISCIII | Beneit N.,Complutense University of Madrid | And 17 more authors.
Cardiovascular Diabetology | Year: 2015

Background: Several translational studies have identified the differential role between saturated and unsaturated fatty acids at cardiovascular level. However, the molecular mechanisms that support the protective role of oleate in cardiovascular cells are poorly known. For these reasons, we studied the protective role of oleate in the insulin resistance and in the atherosclerotic process at cellular level such as in cardiomyocytes (CMs), vascular smooth muscle cells (VSMCs) and endothelial cells (ECs). Methods: The effect of oleate in the cardiovascular insulin resistance, vascular dysfunction, inflammation, proliferation and apoptosis of VSMCs were analyzed by Western blot, qRT-PCR, BrdU incorporation and cell cycle analysis. Results: Palmitate induced insulin resistance. However, oleate not only did not induce cardiovascular insulin resistance but also had a protective effect against insulin resistance induced by palmitate or TNFα. One mechanism involved might be the prevention by oleate of JNK-1/2 or NF-κB activation in response to TNF-α or palmitate. Oleate reduced MCP-1 and ICAM-1 and increased eNOS expression induced by proinflammatory cytokines in ECs. Furthermore, oleate impaired the proliferation induced by TNF-α, angiotensin II or palmitate and the apoptosis induced by TNF-α or thapsigargin in VSMCs. Conclusions: Our data suggest a differential role between oleate and palmitate and support the concept of the cardioprotector role of oleate as the main lipid component of virgin olive oil. Thus, oleate protects against cardiovascular insulin resistance, improves endothelial dysfunction in response to proinflammatory signals and finally, reduces proliferation and apoptosis in VSMCs that may contribute to an ameliorated atherosclerotic process and plaque stability. © 2015 Perdomo et al.

Escribano O.,Complutense University of Madrid | Escribano O.,Health Research Institute of San Carlos Clinic Hospital IdISSC | Escribano O.,Spanish Biomedical Research Center in Diabetes and Associated Metabolic Disorders | Gomez-Hernandez A.,Complutense University of Madrid | And 23 more authors.
Molecular and Cellular Endocrinology | Year: 2015

The main compensatory response to insulin resistance is the pancreatic beta cell hyperplasia to account for increased insulin secretion. In fact, in a previous work we proposed a liver-pancreas endocrine axis with IGF-I (insulin-like growth factor type I) secreted by the liver acting on IRA insulin receptor in beta cells from iLIRKO mice (inducible Liver Insulin Receptor KnockOut) that showed a high IRA/IRB ratio. However, the role of insulin receptor isoforms in the IGF-I-induced beta cell proliferation as well as the underlying molecular mechanisms remain poorly understood. For this purpose, we have used four immortalized mouse beta cell lines: bearing IR (IRLoxP), lacking IR (IRKO), expressing exclusively IRA (IRA), or alternatively expressing IRB (IRB). Pancreatic beta cell proliferation studies showed that IRA cells are more sensitive than those expressing IRB to the mitogenic response induced by IGF-I, acting through the pathway IRA/IRS-1/2/αp85/Akt/mTORC1/p70S6K. More importantly, IRA beta cells, but not IRB, showed an increased glucose uptake as compared with IRLoxP cells, this effect being likely owing to an enhanced association between Glut-1 and Glut-2 with IRA. Overall, our results strongly suggest a prevalent role of IRA in glucose availability and IGF-I-induced beta cell proliferation mainly through mTORC1. These results could explain, at least partially, the role played by the liver-secreted IGF-I in the compensatory beta cell hyperplasia observed in response to severe hepatic insulin resistance in iLIRKO mice. © 2015 Elsevier Ireland Ltd.

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