142 research outputs found
Lipids in the nutritional treatment of inflammatory diseases | Ruolo dei lipidi nel trattamento nutrizionale delle patologie infiammatorie
No full textFatty acids can be broadly divided into saturated, monounsaturated and polyunsaturated acids on the basis of the number of double bonds. Depending on the position of the first double bond, counted from the methyl end, polyunsaturated fatty acids can be further subdivided into series n-3 or n-6. Dietary fatty acids, mainly consisting of essential fatty acids linoleic acid (C18:2, n-6) and linolenic acid (C18:3, n-3), in mammalian cells can be further elongated or desaturated (with the addition of more double bonds). As the elongation and desaturation enzymes are the same for both n-6 and n-3 fatty acids, the two series compete for the same pattern of enzymes for their transformation into fatty acids with a higher number of carbon atoms and double bonds. Polyunsaturated fatty acids of the n-6 and n-3 series are used in the cells mainly as components of biological membrane phospholipids. Following an injurious stimulus starting an inflammatory process, polyunsaturated fatty acids of membrane phospholipids are released into the cell and are transformed into molecules called eicosanoids. Eicosanoids derived from fatty acids of the n-6 series have generally a proinflammation effect, while eicosanoids derived from fatty acids of the n-3 series have an anti-inflammatory and resolutive effect on the triggered inflammatory process. Taken together, these considerations suggest that the introduction of polyunsaturated fatty acids of the n-3 series in an appropriate ratio with respect to fatty acids of the n-6 series may reduce both acute and chronic effects of inflammation. Beneficial effects from the use of polyunsaturated fatty acids of the n-3 series have also been reported in allergic diseases and some forms of respiratory diseases
Effect of dietary fatty acids on the tricarboxylate carrier and on lipogenic enzyme activities in subcellular rat liver fractions
No full textBeneficial effects of n-3 PUFA on chronic airway inflammatory diseases.
No full textChronic airway inflammation is a common symptom of several diseases such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis. Excessive or inappropriate immune system activity and/or failure to resolve an acute inflammation spontaneously can induce functional changes in the walls and parenchyma of the airways. Continuous recruitment of inflammatory cells to the site of inflammation and the production of protein (i.e., cytokines, chemokines, enzymes, etc.) and lipid (eicosanoids) pro-inflammatory mediators contribute directly or indirectly to changes in airway structure and function. Pro-inflammatory eicosanoids are mainly formed by the metabolism of arachidonic acid, an n-6 polyunsaturated fatty acid esterified at the s-n2 position of membrane phospholipids. Unlike n-6 polyunsaturated fatty acids (PUFA), n-3 PUFA decrease inflammation. The anti-inflammatory effect of n-3 PUFA derives from their ability to compete with arachidonic acid in the production of eicosanoids, thereby decreasing the production of pro-inflammatory cytokines and reducing immune cell functions. Moreover, n-3 PUFA can give rise to a series of pro-resolving mediators with anti-inflammatory actions, such as resolvins and protectins. While most studies have reported n-3 PUFA to have beneficial effects on chronic airway diseases, some have questioned the anti-inflammatory effects of n-3 PUFA in inflammatory airway diseases. This paper summarizes the main mechanisms by which n-3 PUFA exert anti-inflammatory and pro-resolving effects, focusing on their use in airway disorders with an inflammatory component
Dietary long-chain unsaturated fatty acids acutely and differently reduce the activities of lipogenic enzymes and of citrate carrier in rat liver
No full textThe activities of lipogenic enzymes appear to fluctuate with changes in the level and type of dietary fats. Polyunsaturated fatty acids (PUFAs) are known to induce on hepatic de novo lipogenesis (DNL) the highest inhibitory effect, which occurs through a long-term adaptation. Data on the acute effects of dietary fatty acids on DNL are lacking. In this study with rats, the acute 1-day effect of high-fat (15 % w/w) diets (HFDs) enriched in saturated fatty acids (SFAs) or unsaturated fatty acids (UFAs), i.e., monounsaturated (MUFA) and PUFA, of the ω-6 and ω-3 series on DNL and plasma lipid level was investigated; a comparison with a longer time feeding (21 days) was routinely carried out. After 1-day HFD administration UFA, when compared to SFA, reduced plasma triacylglycerol (TAG) level and the activities of the lipogenic enzymes acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), a decreased activity of the citrate carrier (CIC), a mitochondrial protein linked to lipogenesis, was also detected. In this respect, ω-3 PUFA was the most effective. On the other hand, PUFA maintained the effects at longer times, and the acute inhibition induced by MUFA feeding on DNL enzyme and CIC activities was almost nullified at 21 days. Mitochondrial fatty acid composition was slightly but significantly changed both at short- and long-term treatment, whereas the early changes in mitochondrial phospholipid composition vanished in long-term experiments. Our results suggest that in the early phase of administration, UFA coordinately reduced both the activities of de novo lipogenic enzymes and of CIC. ω-3 PUFA showed the greatest effect
EFFECT OF SAFFLOWER OIL ON THE TRICARBOXYLATE CARRIER AND ON LIPOGENIC ENZYME ACTIVITIES IN RAT LIVER
No full textCitrate carrier activity and cardiolipin level in eel (Anguilla anguilla) liver mitochondria.
No full textThe activity of the tricarboxylate (citrate) carrier has been assayed in intact liver mitochondria from yellow eel (Anguilla anguilla) and compared to that from rat. The eel-citrate carrier specific activity was approximately 1.7-fold higher than that assayed in rat-liver mitochondria. The content of the main mitochondrial phospholipids, phosphatidylethanolamine and phosphatidylcholine, did not show a significant difference between the two species, while in eel a higher cardiolipin level was observed. Fatty acid composition of eel-liver mitochondrial phospholipids was characterised by a large amount of unsaturated fatty acids, dominated by octadecaenoic acid (C18:1n-9) and docosahexaenoic acid (C22:6n-3). The cardiolipin fatty acid pattern of eel-liver mitochondria showed, with respect to the rat, a higher C20:5n-3 and C22:6n-3 content and a lower amount of C18:2n-6 and C20:4n-6. A noticeable activity of lipogenic enzymes was also detected in eel liver cytosol. The results of this study suggest that the remarkable activity of the citrate carrier in eel-liver mitochondria can most likely be ascribed to a considerable cardiolipin level. A covariance of citrate carrier and lipogenic enzyme activities was observed. © 2002 Elsevier Science Inc. All rights reserved
Effect of polyunsaturated fatty acids on the activities of mitochondrial tricarboxylate carrier and of lipogenic enzymes in rat liver
No full textEFFECT OF POLYUNSATURATED FATTY ACIDS ON THE ACTIVITIES OF MITOCHONDRIAL TRICARBOXYLATE CARRIER AND OF LIPOGENIC ENZYMES IN RAT LIVER
No full textMitochondrial tricarboxylate carrier and de novo fatty acid synthesis in Anguilla anguilla
No full textEffetto degli acidi grassi della dieta sull'attività del carrier mitocondriale del citrato e sulla composizione lipidica delle membrane mitocondriali
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