Dietary polyunsaturated fatty acids and adaptation to chronic hypoxia alter acyl composition of serum and heart lipids

Abstract

The effects of dietary supplementation with fat of different fatty acid profile and chronic intermittent hypoxia (CIH) on the fatty acid composition of serum and heart lipids were analysed. Adult male Wistar rats were fed a standard non-fat diet enriched with 10 % of lard, fish oil (n-3 PUFA) or maize oil (n-6 PUFA) for 10 weeks. After 4 weeks on the diets, each group was divided in two subgroups, either exposed to CIH in a barochamber (7000 m, twenty-five exposures) or kept at normoxia. In normoxic rats, the fish oil diet increased the level of conjugated dienes. The n-6:n-3 PUFA ratio in serum TAG, phospholipids (PL), cholesteryl esters (CE) and heart TAG, PL and diacylglycerols (DAG) followed the ratio in the fed diet (in the sequence maize oil>lard>fish oil). In heart TAG, PL and DAG, 20 : 4n-6 and 18 : 2n-6 were replaced by 22 : 6n-3 in the fish oil group. The main fatty acid in CE was 20 : 4n-6 in the lard and maize oil groups whereas in the fish oil group, half of 20 : 4n-6 was replaced by 20 : 5n-3. CIH further increased 20 : 5n-3 in CE in the fish oil group. CIH decreased the n-6:n-3 PUFA ratio in serum CE, heart TAG, PL and DAG in all dietary groups and stimulated the activity of catalase in the maize and fish oil groups. In conclusion, PUFA diets and CIH, both interventions considered to be cardioprotective, distinctly modified the fatty acid profile in serum and heart lipids with specific effects on conjugated diene production and catalase activity.

Fasting enriches liver triacylglycerol with n-3 polyunsaturated fatty acids: implications for understanding the adipose–liver axis in serum docosahexaenoic acid regulation

“…Additionally, fasting mediated an absolute and relative reduction in the concentration of serum TAG linoleic acid that was opposite to the enrichment in liver TAG 18:2n-6 that was coordinately observed. Overall, our results are in line with prior work indicating that the pools of n-3 and n-6 PUFA in serum TAG are considerably smaller than pools in phospholipid (*75 to 90 % lower) and that serum TAG 22:6n-3 is a relatively minor transport source in blood (Crowe et al 2008;Balkova et al 2009).…”

“…While serum TAG is not typically considered a major pool for the transport of n-3 or n-6 PUFA (Crowe et al 2008;Balkova et al 2009), it is still of interest to examine fasting-mediated changes in the composition of this complex lipid in serum. The fatty acid profile of serum TAG is generally expected to mirror that of the hepatic TAG from which it is derived (Hyysalo et al 2014;Donnelly et al 2005).…”

Amelioration of oxidative and inflammatory status in hearts of cholesterol-fed rats supplemented with oils or oil-products with extra virgin olive oil components

“…Since in our study there was no differentiation between heart triacylglycerols and phospholipids, this might be a confusing factor for heart fatty acid profile, thus in the evaluation of our results as well. As for heart n-6/n-3 ratio, it was influenced by dietary n-6 PUFA in line with other studies [52]. In humans, the n-6/n-3 ratio is positively related to inflammation and coagulation markers [54].…”

“…Homogeneity was expected for EVOO and HOSO but not for SO, the latter having a different fatty acid profile. This fact may be explained by membrane phospholipids' ability to retain proportions of fatty acids classes rather constant, independently of the diet applied, so as to maintain a stable milieu which is necessary for proper membrane function [52]. As for oil/oil-product comparisons, SO(+) group presented lower amounts of 18:1 n-9 and higher amounts of 18:2 n-6 fatty acids in situ, compared with SO.…”

Importância da relação dos ácidos graxos omega-6/omega-3 na alimentação

“…Foi sugerido que o ácido α-linolênico pode não ser incorporado tão eficientemente pelas moléculas de fosfolipídios e lipoproteínas. Balková et al (2009) utilizaram camundongos como modelo experimental para comparar ácidos graxos saturados, monoinsaturados e poli-insaturados, suplementando os animais durante dez semanas com ração sem gordura, enriquecida com 10% de gordura suína no primeiro grupo, 10% de óleo de peixe como fonte de n-3 no grupo 2 e óleo de milho como fonte de n-6 no grupo 3. Ao serem analisados no soro dos camundongos, observou-se que houve um decréscimo dos ácidos graxos saturados e monoinsaturados a favor dos poli-insaturados na seguinte sequência: gordura suína > óleo de peixe > óleo de milho.…”