Enteral nutrition with eicosapentaenoic acid, gamma-linolenic acid, and antioxidants reduces alveolar inflammatory mediators and protein influx in patients with acute respiratory distress syndrome.

Abstract

OBJECTIVE:

Previously, we showed that acute respiratory distress syndrome patients fed an enteral diet containing eicosapentaenoic acid and gamma-linolenic acid and elevated antioxidants (EPA+GLA; Oxepa) had significantly reduced pulmonary inflammation, increased oxygenation, and improved clinical outcomes. In a subset of acute respiratory distress syndrome patients from this trial, we performed a preliminary examination of the potential mechanisms underlying these clinical improvements by retrospectively testing the hypothesis that enteral feeding with EPA+GLA could reduce alveolar-capillary membrane protein permeability and the production of interleukin (IL)-8, IL-6, tumor necrosis factor-alpha, and leukotriene B4 that are responsible, in part, for pulmonary inflammation.

DESIGN:

Prospective, randomized, double-blind, controlled clinical trial.

SETTING:

Intensive Care Unit of the Ohio State University Medical Center.

PATIENTS:

A total of 67 patients were enrolled who met defined criteria for acute lung injury/acute respiratory distress syndrome.

INTERVENTIONS:

A total of 43 of 67 evaluable patients randomly received either EPA+GLA or an isonitrogenous, isocaloric standard diet that was tube fed at a minimum caloric delivery of 75% of basal energy expenditure times 1.33 for at least 4 to 7 days.

MEASUREMENTS AND MAIN RESULTS:

Bronchoalveolar lavage (BAL) was performed at baseline and study days 4 and 7 to obtain BAL fluid (BALF) for measurement of total protein, ceruloplasmin, and transferrin, total neutrophil count, IL-8, IL-6, tumor necrosis factor-alpha, and leukotriene B4. Oxygenation, measured as Pao2/Fio2, was assessed before BAL. Patients fed EPA+GLA had a significant reduction in BALF ceruloplasmin and IL-8 during the study as compared with patients fed the control diet. BALF levels of total protein, neutrophils, and leukotriene B4 tended to decrease in EPA+GLA patients over the course of the study as compared with control patients. BALF levels of IL-6 declined similarly during the study in both groups. A trend toward a reduction in BALF tumor necrosis factor-alpha was observed on study day 7 in the EPA+GLA group as compared with control patients. Significant improvements in oxygenation (Pao2/Fio2) occurred in EPA+GLA patients on study day 4 as compared with controls. Correlation analysis revealed significant relationships between BALF neutrophil counts and indices of alveolar-capillary membrane protein permeability, IL-8, and leukotriene B4.

CONCLUSIONS:

This preliminary investigation showing a decrease in BALF levels of IL-8 and leukotriene B4 and the associated reduction of BALF neutrophils and alveolar membrane protein permeability in acute respiratory distress syndrome patients fed EPA+GLA support, in part, the potential mechanisms underlying the previously described clinical improvements with this diet. Additional controlled studies are needed to confirm these findings.

• Authors: Eric R Pacht, Stephen J DeMichele, Jeffrey L Nelson, Judy Hart, Ann K Wennberg, James E Gadek
• Journal: Critical care medicine (Crit Care Med) Vol. 31 Issue 2 Pg. 491-500 (Feb 2003) ISSN: 0090-3493 [Print] United States
• PMID: 12576957 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Antioxidants
• Inflammation Mediators
• Proteins
• gamma-Linolenic Acid
• Eicosapentaenoic Acid

Topics

• Antioxidants (pharmacology)
• Double-Blind Method
• Eicosapentaenoic Acid (pharmacology)
• Enteral Nutrition
• Female
• Humans
• Inflammation Mediators (physiology)
• Male
• Middle Aged
• Prospective Studies
• Proteins (drug effects, metabolism)
• Pulmonary Alveoli (drug effects, immunology)
• Respiratory Distress Syndrome (immunology, therapy)
• gamma-Linolenic Acid (pharmacology)