Reduction in the desaturation capacity of the liver in mice subjected to high fat diet: Relation to LCPUFA depletion in liver and extrahepatic tissues

Extra virgin olive oil reduces liver oxidative stress and tissue depletion of long-chain polyunsaturated fatty acids produced by a high saturated fat diet in mice

“…Another interesting aspect of EVOO is its high content of 18:1 n-9, which, although it is more stable to lipo-oxidation compared to PUFAs, can be also oxidized in low quantity, which could generate a protective response as an increase in cellular antioxidant defenses (Haeiwa et al, 2014). The decrease in n-3 and n-6 LCPUFA observed in the three tissues studied may be a consequence of the oxidative stress induced by the HFD, which has an impact on the reduction in the activity of desaturase enzymes (Δ-5 and Δ-6 desaturases), as previously shown (Valenzuela et al, 2015). In this way, the antioxidant components of EVOO would protect the effect of a HFD on the activity of desaturase enzymes in the liver, on the tissue levels of n-3 and n-6 LCPUFA, on lipoperoxidation as measured through F2-isoprostanes and TBARS (Table 3), and on the negative correlation of lipoperoxidation parameters and liver levels of FIGURE 2.…”

“…The HFD also produced an increase in reticular stress in mice which can cause alterations in the folding of hepatic proteins (Lu et al, 2015), potentially modifying many enzymatic functions . Liver fat accumulation and oxidative stress would be linked to the reduction of the n-3 and n-6 LCPUFA observed in the liver, erythrocytes and the brain (Tables 4 to 6), effects that may be directly linked to the increase in systemic and hepatic oxidative stress parameters previously observed in the mice fed the HFD (Valenzuela et al, 2015). It has been described that the accumulation of fat in the liver (from over load of saturated fat and refined carbohydrates of nutritional origin) generates a decrease in the activity of the nuclear peroxisome proliferator-activated receptor transcription factor alpha (PPAR-α) as a direct consequence of the reduction in tissue levels of n-3 LCPUFA and, in addition, an increase in the activity of the sterol regulatory element binding protein transcription factor -1 c (SREBP-1 c) (Pawlak et al, 2015), thus promoting a pro-lipogenic state, particularly expressed as greater synthesis of 16:0, as shown in tables 4, 5 and 6, and a reduction in the oxidation of fatty acids as a source of energy (Cheng et al, 2015).…”

“…Extra virgin olive oil reduces liver oxidative stress and tissue depletion • 9 at the intracellular level, which may protects against the oxidation of proteins (Table 3) and preserve the activity of redox-sensitive enzymes, such as desaturases (Nakamura and Nara, 2004;Valenzuela et al, 2015). Another interesting aspect of EVOO is its high content of 18:1 n-9, which, although it is more stable to lipo-oxidation compared to PUFAs, can be also oxidized in low quantity, which could generate a protective response as an increase in cellular antioxidant defenses (Haeiwa et al, 2014).…”

“…The formation of AA from LA is not limiting because of the high availability of LA in the typical western diet (Simopoulos, 2011). The activity of desaturases is positively regulated by insulin (Guillou et al, 2010) and is very sensitive to the cellular redox state (Nakamura and Nara, 2004) modified by oxidative stress, which reduces the activity of desaturases (Valenzuela et al, 2015). Oxidative stress produced by reactive oxygen species (free radicals) is associated to lipoperoxidation, which in turn is associated with the origin and/or progression of many diseases (Videla et al, 2006), being an important component of the deleterious effects of obesity (Videla et al, 2004), and other non-transmissible chronic diseases (Li et al, 2004;Marseglia et al, 2014).…”

“…Oxidative stress produced by reactive oxygen species (free radicals) is associated to lipoperoxidation, which in turn is associated with the origin and/or progression of many diseases (Videla et al, 2006), being an important component of the deleterious effects of obesity (Videla et al, 2004), and other non-transmissible chronic diseases (Li et al, 2004;Marseglia et al, 2014). A diet high in saturated fat, particularly containing palmitic acid (C16:0), increases liver oxidative stress reducing n-3 and n-6 LCPUFA (EPA, DHA and AA) in different tissues, such as erythrocytes, brain, heart, liver and adipose tissue (Valenzuela et al, 2015).…”