Oral administration of docosahexaenoic acid/eicosapentaeinoic acids is not anticonvulsant in rats: implications for translational research.

Omega-3 and omega-6 poly-unsaturated fatty acids (PUFAs) are dietary fatty acids that are involved in a myriad of physiological processes in the brain. Although experimental data have shown that PUFAs have anticonvulsant properties, the outcomes of clinical trials have been controversial. Docosahexaenoic acid (DHA) is a PUFA which has been reported to exert anticonvulsant effects. Here we studied anticonvulsant potential of a mixture of enriched n-3 PUFA upon their oral administration in rats. We did not observe an anticonvulsant effect of n-3 PUFA in the i.v. pentylentetrazol threshold test. n-3 PUFA component was increased in the plasma of rats treated with the eicosapentaenoic acid (EPA)/DHA mix (275 mg/kg/d/400 mg/kg/d) due to the increase of both DHA and EPA. We also found modification of PUFA composition in the brain. Despite PUFA profiles modified both in plasma and in the brain, we did not find any anticonvulsant effect of orally administered DHA. Further studies are needed to define the type and the amount of fatty acids that would possess anticonvulsant properties. As the existing literature suggests that the route of administration of PUFA may be crucial, future studies should involve oral administration to provide relevant clinical information.

Dietary (n-3) polyunsaturated fatty acids affect the kinetics of pro- and antiinflammatory responses in mice with Pseudomonas aeruginosa lung infection.

The underlying mechanisms by which eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) affect host resistance to Pseudomonas aeruginosa are unclear. The aim of this study was to determine their role on the kinetic of pro- and antiinflammatory response in lung infection. Mice fed either a control diet or a diet enriched with EPA and DHA were infected intratracheally and we studied lung expression of proinflammatory markers [CXCL1, interleukin (IL)-6, tumor necrosis factor-alpha], antiinflammatory markers (IL-10, A20, and IkappaB alpha), and PPARalpha and PPARgamma. The inflammatory response was assessed using recruitment of neutrophils and macrophages into bronchoalveolar lavage fluid, bacterial clearance from the lung, pulmonary injury, and 7-d survival rate. Compared with the control group, EPA and DHA delayed the expression of proinflammatory markers during the first 2 h (P < 0.05), upregulated proinflammatory marker expression (P < 0.05), and induced overexpression of antiinflammatory markers at 8 h (P < 0.05), enhanced recruitment of neutrophils at 16 h (P < 0.05), and induced PPARalpha and PPARgamma overexpression at 4 and 8 h (P < 0.01), respectively. Pulmonary bacterial load decreased and pulmonary injury and mortality were reduced during the first 24 h (P < 0.05). In conclusion, EPA and DHA modulate the balance between pro- and antiinflammatory cytokines, alter the early response of the host to P. aeruginosa infection, and affect the early outcome of infection.

Anticonvulsant effects of linolenic acid are unrelated to brain phospholipid cell membrane compositions.

PURPOSE: Recent studies have revealed that polyunsaturated fatty acids (PUFAs) have anticonvulsive properties. Clinical trials using PUFAs reported conflicting results. It was suggested that PUFAs have anticonvulsant effects via modifications of brain phospholipids. Moreover, some authors suggested that the effect of the ketogenic diet (KD) leads to a high PUFA content. The aim of the study was to evaluate the anticonvulsant properties of a mixture containing alpha-linolenic acid (ALA) and linolenic acid (LA). METHODS: Four-week-old male Wistar rats were fed one of the following diets for 30 days: KD, standard diet, and standard diet with daily LA/ALA oral supplementation. Pentylenetetrazol (PTZ) threshold was used to assess the anticonvulsive effects of the diets. Nutritional status was monitored by body composition evaluation. Fatty acids composition of both plasma and brain phospholipids were also assessed. RESULTS: Animals fed the KD and those who had the daily LA/ALA supplementation exhibited an increase in PTZ threshold. The animals did not show any modification of body composition or brain phospholipid composition. The plasma fatty acids composition was modified by KD and LA/ALA. A decrease in arachidonic acid (AA) concentrations was observed in both the KD and LA/ALA groups, while an increase in eicosapentanoic acid (EPA) and ALA concentrations was only observed in the LA/ALA group. CONCLUSIONS: Our study shows that LA/ALA supplementation exerts anticonvulsive properties comparable to KD. Nutritional status can not explain the anticonvulsive effects of PUFAs supplementation. Brain phospholipids were not different within groups. The anticonvulsive effects of LA supplementation seem to be unrelated to brain phospholipid composition.

Dietary n-3 fatty acids have suppressive effects on mucin upregulation in mice infected with Pseudomonas aeruginosa.

BACKGROUND: Mucin hypersecretion and mucus plugging in the airways are characteristic features of chronic respiratory diseases like cystic fibrosis (CF) and contribute to morbidity and mortality. In CF, Pseudomonas aeruginosa superinfections in the lung exacerbate inflammation and alter mucus properties. There is increasing evidence that n-3 polyunsaturated fatty acids (PUFAs) exhibit anti-inflammatory properties in many inflammatory diseases while n-6 PUFA arachidonic acid (AA) favors inflammatory mediators such as eicosanoids prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) that may enhance inflammatory reactions. This suggests that n-3 PUFAs may have a protective effect against mucus over-production in airway diseases. Therefore, we hypothesized that n-3 PUFAs may downregulate mucins expression. METHODS: We designed an absolute real-time PCR assay to assess the effect of a 5-week diet enriched either with n-3 or n-6 PUFAs on the expression of large mucins in the lungs of mice infected by P. aeruginosa. RESULTS: Dietary fatty acids did not influence mucin gene expression in healthy mice. Lung infection induced an increase of the secreted gel-forming mucin Muc5b and a decrease of the membrane bound mucin Muc4. These deregulations are modulated by dietary fatty acids with a suppressive effect of n-3 PUFAs on mucin (increase of Muc5b from 19-fold up to 3.6 x 10(5)-fold for the n-3 PUFAs treated group and the control groups, respectively, 4 days post-infection and decrease of Muc4 from 15-fold up to 3.2 x 10(4)-fold for the control and the n-3 PUFAs treated groups, respectively, 4 days post-infection). CONCLUSION: Our data suggest that n-3 PUFAs enriched diet represents an inexpensive strategy to prevent or treat mucin overproduction in pulmonary bacterial colonization.

Omega-3 polyunsaturated fatty acids improve host response in chronic Pseudomonas aeruginosa lung infection in mice.

Pseudomonas aeruginosa is a gram-negative bacilli frequently encountered in human pathology. This pathogen is involved in a large number of nosocomial infections and chronic diseases. Herein we investigated the effects of polyunsaturated fatty acids (PUFA) in chronic Pseudomonas aeruginosa lung infection. C57BL/6 mice were fed for 5 wk with specifically designed diets with high contents in either omega-3 (omega-3) or omega-6 PUFA and compared to a control diet. P. aeruginosa included in agarose beads was then instilled intratracheally, and the animals were studied for 7 days. On the 4th day, the mice fed with the omega-3 diet had a higher lean body mass gain and a lower omega-6:omega-3 ratio of fatty acids extracted from the lung tissue compared with the other groups (P < 0.05). The omega-3 group had the lowest mortality. Distal alveolar fluid clearance (DAFC) as well as the inflammatory response and the cellular recruitment were higher in the omega-3 group on the 4th day. The effect on DAFC was independent of alpha-epithelial Na(+) channels (alpha-ENaC), beta-ENaC, and alpha(1)-Na-K-ATPase mRNA expressions, which were not altered by the different diets. In conclusion, a diet enriched in omega-3 PUFA can change lung membrane composition and improve survival in chronic pneumonia. This effect on survival is probably multifactorial involving the increased DAFC capacity as well as the optimization of the initial inflammatory response. This work suggests that a better control of the omega-6/omega-3 PUFA balance may represent an interesting target in the prevention and/or control of P. aeruginosa infection in patients.