Polyphenol‐rich virgin olive oil reduces insulin resistance and liver inflammation and improves mitochondrial dysfunction in high‐fat diet fed rats

• Published in: Molecular nutrition & food research 2017-03, Vol.61 (3), p.np-n/a
• Main Authors: Lama, Adriano, Pirozzi, Claudio, Mollica, Maria Pia, Trinchese, Giovanna, Di Guida, Francesca, Cavaliere, Gina, Calignano, Antonio, Mattace Raso, Giuseppina, Berni Canani, Roberto, Meli, Rosaria
• Format: Article
• Language: English
• Subjects: Adipokines - blood; Animals; Anti-inflammatory agents; Cytokines; Cytokines - blood; Diet, High-Fat - adverse effects; Disease Models, Animal; Emissions control; Energy efficiency; Energy management; Essential oils; Fatty acids; Fatty liver; Glucose; Glucose - metabolism; Glucose tolerance; Hepatitis - diet therapy; Hepatitis - etiology; Hepatitis - physiopathology; High fat diet; Homeostasis; Hydrogen peroxide; Hyperglycemia; Inflammation; Insulin; Insulin Resistance; Interleukin 1; Interleukin 10; Lipid Metabolism - drug effects; Liver; Liver diseases; Male; Mediterranean diet; Mitochondria; Mitochondria, Liver - drug effects; Mitochondria, Liver - metabolism; Mitochondrial and hepatic oxidative stress; Non-alcoholic Fatty Liver Disease - diet therapy; Non-alcoholic Fatty Liver Disease - physiopathology; Nonalcoholic Fatty liver disease; Oils & fats; Olive oil; Olive Oil - chemistry; Olive Oil - pharmacology; Olive oil polyphenols; Oxidation; Oxidation resistance; Oxidative stress; Oxidative Stress - drug effects; Phenolic compounds; Phenols; Polyphenols; Polyphenols - pharmacology; Power efficiency; Rats; Rats, Sprague-Dawley; Reactive oxygen species; Rodents; Tocopherols - pharmacology; Tumor necrosis factor
• ISSN: 1613-4125; 1613-4133
• DOI: 10.1002/mnfr.201600418

Scope Virgin olive oil is an essential component of the Mediterranean diet. Its antioxidant and anti‐inflammatory properties are mainly linked to phenolic contents. This study aims to evaluate the beneficial effects of a polyphenol‐rich virgin olive oil (HPCOO) or olive oil without polyphenols (WPOO) in rats fed high‐fat diet (HFD). Methods and results Male Sprague‐Dawley rats were divided into four groups based on the different types of diet: (I) standard diet (STD); (II) HFD; (III) HFD containing WPOO, and (IV) HFD containing HPCOO. HPCOO and WPOO induced a significant improvement of HFD‐induced impaired glucose homeostasis (by hyperglycemia, altered oral glucose tolerance, and HOMA‐IR) and inflammatory status modulating pro‐ and anti‐inflammatory cytokines (TNF‐α, IL‐1, and IL‐10) and adipokines. Moreover, HPCOO and less extensively WPOO, limited HFD‐induced liver oxidative and nitrosative stress and increased hepatic fatty acid oxidation. To study mitochondrial performance, oxidative capacity and energy efficiency were also evaluated in isolated liver mitochondria. HPCOO, but not WPOO, reduced H2O2 release and aconitase activity by decreasing degree of coupling, which plays a major role in the control of mitochondrial reactive oxygen species emission. Conclusion HPCOO limits HFD‐induced insulin resistance, inflammation, and hepatic oxidative stress, preventing nonalcoholic fatty liver disease progression. Nonalcoholic fatty liver disease is characterized by insulin resistance, hepatic inflammation and mitochondrial oxidative stress. Polyphenol‐rich virgin olive oil (HPCOO) is able to reduce pro‐inflammatory mediators (TNF‐α, IL‐1, COX‐2, and leptin) and to increase anti‐inflammatory ones (IL‐10 and adiponectin). Moreover, HPCOO restores glucose homeostasis and increases fatty acid oxidation, activating AMPK/AKT pathway and PPAR‐α transcription, and improves mitochondrial oxidative stress, inhibiting aconitase activity and reactive oxygen species and H2O2 production.