IMMUNE MODULATION BY POLYUNSATURATED FATTY-ACIDS DURING NUTRITIONAL THERAPY - INTERACTIONS WITH SYNTHESIS AND EFFECTS OF EICOSANOIDS

Objective: Review of the range of action of polyunsaturated fatty acid s (PUFAs) on the basis of interactions with eicosanoids. Discussion of the clinical relevance of these actions. Data Sources: Original paper s and reviews of the pertinent literature in German and English, cover ed by repeated MEDLINE searches. Selection Criteria: Pertinent origina l papers and review articles from 1983 on, as well as some significant original papers of earlier origin with main emphasis on studies conce rned with the pharmacodynamic interactions between PUFAs, eicosanoids and the immune system. Results: PUFAs are precursors of eicosanoid for mation. Interactions between PUFAs and the immune system are influence d by the rate of synthesis as well as by the efficacy of the various e icosanoids. The rate of eicosanoid synthesis is determined by PUFA tur nover. In the absence of essential fatty acid deficiency (EFAD), PUFA turnover depends on the activity of phospholipases. Activities are enh anced under the influence of stress factors such as trauma and sepsis. The efficacy of eicosanoids is determined by the availability of diff erent PUFAs in the cellular phospholipid pool, whereby n-6 and n-3 PUF As give rise to eicosanoids of different series. The eicosanoids forme d from n-3 PUFAs, compared to those derived from n-6 PUFAs, develop si milar quality but less intensity of action. Therefore, eicosanoids of different origin induce different effects at a given rate of synthesis . Conclusions: Appropriate dietary alterations of the availability of n-6 and n-3 PUFAs together with the resulting influence on synthesis a nd action of mediators, possibly might serve as a pharmacological tool to influence systemic functions in critically ill patients in the fut ure.