alpha-Linolenic and linoleic acids and the immune response

Molecular Mechanisms and Therapeutics for Spinocerebellar Ataxia Type 2

The effective therapeutic treatment and the disease-modifying therapy for spinocerebellar ataxia type 2 (SCA2) (a progressive hereditary disease caused by an expansion of polyglutamine in the ataxin-2 protein) is not available yet. At present, only symptomatic treatment and methods of palliative care are prescribed to the patients. Many attempts were made to study the physiological, molecular, and biochemical changes in SCA2 patients and in a variety of the model systems to find new therapeutic targets for SCA2 treatment. A better understanding of the uncovered molecular mechanisms of the disease allowed the scientific community to develop strategies of potential therapy and helped to create some promising therapeutic approaches for SCA2 treatment. Recent progress in this field will be discussed in this review article.

The Effects of Immediate Enteral Feeding with a Formula Containing High Levels of ω-3 Fatty Acids in Patients After Surgery for Esophageal Cancer

BACKGROUND

We investigated whether supplementation of enteral nutrition (EN) with omega-3 polyunsaturated acids (PUFAs) affected platelet aggregation, coagulation activity, and inflammatory response in the early stages after esophageal cancer surgery.

METHODS

Twenty-eight patients with esophageal cancer who underwent the same surgical procedure were selected for this study. All patients received EN, which was started immediately after the operation and was increased to a maximum volume of 1500 ml/day by the third postoperative day (POD). Eleven patients received a conventional EN formula (Ensure Liquid), while the remaining 17 patients received a different formula rich in omega-3 PUFAs (Racol [RAC]). Several markers of coagulation and fibrinolysis were determined in POD 2, while the concentrations of interleukin (IL)-6, IL-8, 6-keto-PGF1alpha and thromboxane B2 were determined on PODs 1, 3, and 5.

RESULTS

A total of 27 patients completed the study, 11 in the Ensure Liquid group and 16 in the RAC group. Administration of RAC significantly inhibited the postoperative decrease in platelet count. The level of D-dimer was attenuated significantly in the RAC group. Plasma IL-8 levels were decreased significantly in the RAC group on PODs 1 and 3. The anti-inflammatory effects of omega-3 PUFAs were confirmed by the clinical findings of lower body temperature. The plasma concentration of 6-keto-PFG1alpha also tended to decrease in the RAC group with a significant difference on POD 5.

CONCLUSIONS

Early EN with a large amount of omega-3 PUFAs in reduced platelet aggregation, coagulation activity, and cytokine production. All these effects would be expected to be beneficial in patients following esophageal cancer surgery. The clinical significance of the changes in eicosanoid production remains to be established.

Omega-3 fatty acids and metabolic syndrome: effects and emerging mechanisms of action

Epidemiological, human, animal, and cell culture studies show that n-3 fatty acids, especially α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), reduce the risk factors of cardiovascular diseases. EPA and DHA, rather than ALA, have been the focus of research on the n-3 fatty acids, probably due to the relatively inefficient conversion of ALA to EPA and DHA in rodents and humans. This review will assess our current understanding of the effects and potential mechanisms of actions of individual n-3 fatty acids on multiple risk factors of metabolic syndrome. Evidence for pharmacological responses and the mechanism of action of each of the n-3 fatty acid trio will be discussed for the major risk factors of metabolic syndrome, especially adiposity, dyslipidemia, insulin resistance and diabetes, hypertension, oxidative stress, and inflammation. Metabolism of n-3 and n-6 fatty acids as well as the interactions of n-3 fatty acids with nutrients, gene expression, and disease states will be addressed to provide a rationale for the use of n-3 fatty acids to reduce the risk factors of metabolic syndrome.

Effect of a fish oil structured lipid-based diet on prostaglandin release from mononuclear cells in cancer patients after surgery

BACKGROUND

The authors compared the effect on eicosanoid production (prostaglandin E2 [PGE2], 6-keto PGF 1 alpha, and thromboxane B2) from peripheral blood mononuclear cells (PBMC) of feeding an enteral diet containing a fish oil/medium-chain triglyceride structured lipid (FOSL-HN) vs an isonitrogenous, isocaloric formula (O-HN) in patients undergoing major abdominal surgery for upper gastrointestinal malignancies. A previous study, which used the same formulas and experimental design, suggested improved renal and liver function as well as a reduced number of gastrointestinal and infectious complications with the use of fish oil structured lipids. This study sought to investigate the potential mechanism for these effects by assessing eicosanoid production from PBMC with the two diets.

METHODS

This prospective, blinded, randomized trial was conducted in 20 patients who were jejunally fed either FOSL-HN or O-HN for 7 days. Serum chemistries, hematology, urinalysis, gastrointestinal complications, liver and renal function, and eicosanoid production from isolated PBMC, either unstimulated or stimulated with endotoxin, were measured at endotoxin baseline and on day 7. Comparisons were made in 10 and 8 evaluable patients based a priori on the ability to reach a tube feeding rate of > 40 mL/h.

RESULTS

Patients receiving FOSL-HN experienced no untoward side effects compared with patients given O-HN and demonstrated the same general trend toward improved hepatic, renal and immune function found in the previous study. There was a significant reduction in PGE2 (p < .03) and 6-keto PGF 1 alpha (p < .01) production from PBMC with endotoxin stimulation in patients receiving FOSL-HN.

CONCLUSIONS

The results of early enteral feeding with FOSL-HN after surgery in this follow-up study provide further support to claims of safety, tolerance, and improved physiologic function. There was an associated reduction in eicosanoid production from PBMCs, which is presumed to be the principal mechanism for these effects.

Early enteral feeding in postsurgical cancer patients. Fish oil structured lipid-based polymeric formula versus a standard polymeric formula

OBJECTIVES

The authors compared the safety, gastrointestinal tolerance, and clinical efficacy of feeding an enteral diet containing a fish oil/medium-chain triglyceride structured lipid (FOSL-HN) versus an isonitrogenous, isocaloric formula (O-HN) in patients undergoing major abdominal surgery for upper gastrointestinal malignancies.

SUMMARY BACKGROUND DATA

Previous studies suggest that feeding with n-3 fatty acids from fish oil can alter eicosanoid and cytokine production, yielding an improved immunocompetence and a reduced inflammatory response to injury. The use of n-3 fatty acids as a structured lipid can improve long-chain fatty acid absorption.

METHODS

This prospective, blinded, randomized trial was conducted in 50 adult patients who were jejunally fed either FOSL-HN or O-HN for 7 days. Serum chemistries, hematology, urinalysis, gastrointestinal complications, liver and renal function, plasma and erythrocyte fatty acid analysis, urinary prostaglandins, and outcome parameters were measured at baseline and on day 7. Comparisons were made in 18 and 17 evaluable patients based a priori on the ability to reach a tube feeding rate of 40 mL/hour.

RESULTS

Patients receiving FOSL-HN experienced no untoward side effects, significant incorporation of eicosapentaenoic acid into plasma and erythrocyte phospholipids, and a 50% decline in the total number of gastrointestinal complications and infections compared with patients given O-HN. The data strongly suggest improved liver and renal function during the postoperative period in the FOSL-HN group.

CONCLUSION

Early enteral feeding with FOSL-HN was safe and well tolerated. Results suggest that the use of such a formula during the postoperative period may reduce the number of infections and gastrointestinal complications per patient, as well as improve renal and liver function through modulation of urinary prostaglandin levels. Additional clinical trials to fully quantify clinical benefits and optimize nutritional support with FOSL-HN should be undertaken.

Supplementation of polyunsaturated fatty acids in multiple sclerosis

For several years polyunsaturated fatty acids (PUFAs) and in particular essential fatty acids (EFAs) have been proposed for the treatment of multiple sclerosis (MS). There are contrasting data in literature regarding the effects of the n-6 and the n-3 PUFA series on different aspects of the disease, in particular on the frequency and severity of relapses and platelet function. This can be ascribed to the different criteria of patient selection in relation to the form and severity of disease at the beginning of the various studies. Till now authors have tended to consider the effect of PUFA supplementation only on some clinical aspects of the disease. Modification in the more sensitive indices (immunological or biochemical) of the disease activity should be taken into account and also the influence of dietary lipid intake by patients in relation to n-3 or n-6 EFA supplementation.

Modulation of tissue prostaglandin synthesizing capacity by increased ratios of dietary alpha-linolenic acid to linoleic acid

Semipurified diets containing ratios of alpha-linolenic acid (18:3 omega 3) to linoleic acid (18:2 omega 6) of 1/32, 1/7, 1/1, and 3.5/1 in the form of corn oil, soybean oil, soybean/linseed oil mix and linseed oil were fed to rats for 2 months. The first 3 diets were fed to another group of rats for 4 months and to a group through the second generation. Fatty acid analysis of liver and spleen ethanolamine glycerophosphatide revealed that, as the level of 18:3 omega 3 in the diet increased, the elongated, desaturated metabolites of the omega 6 series decreased and the omega 3 series increased. Noteworthy was the depression in the amount of the precursor of the 2-series prostaglandins (PG) as the omega 3 levels increased. Synthesis of PG by liver of rats fed 2 or 4 months markedly decreased, but at 2 months in thymus and spleen, it showed a trend toward decreasing only. Brain slices showed no decrease in PGF2 alpha synthesis after 4 months, but did decrease significantly after feeding the diets to the second generation. Synthesis of PGE2 by spleen homogenate from the second generation also significantly decreased. The replacement of omega 6 series fatty acids by omega 3 series is explained by the effective competition of 18:3 omega 3 over 18:2 omega 6 for the delta 6 desaturase. Depressions in PG synthesis by high dietary 18:3 omega 3 is explained by the competitive inhibition of the PG synthetase complex by 20:5 omega 3 as well as by the decreased levels of 20:4 omega 6.