Fatty Acid Composition Of Phospholipid Classes Research Articles

Prenatal Ethanol Exposure Increases Brain Cholesterol Content in Adult Rats

Fetal alcohol syndrome is the most severe expression of the fetal alcohol spectrum disorders (FASD). Although alterations in fetal and neonate brain fatty acid composition and cholesterol content are known to occur in animal models of FASD, the persistence of these alterations into adulthood is unknown. To address this question, we determined the effect of prenatal ethanol exposure on individual phospholipid class fatty acid composition, individual phospholipid class mass, and cholesterol mass in brains from 25-week-old rats that were exposed to ethanol during gestation beginning at gestational day 2. While total phospholipid mass was unaffected, phosphatidylinositol and cardiolipin mass was decreased 14 and 43%, respectively. Exposure to prenatal ethanol modestly altered brain phospholipid fatty acid composition, and the most consistent change was a significant 1.1-fold increase in total polyunsaturated fatty acids (PUFA), in the n-3/n-6 ratio, and in the 22:6n-3 content in ethanolamine glycerophospholipids and in phosphatidylserine. In contrast, prenatal ethanol consumption significantly increased brain cholesterol mass 1.4-fold and the phospholipid to cholesterol ratio was significantly increased 1.3-fold. These results indicate that brain cholesterol mass was significantly increased in adult rats exposed prenatally to ethanol, but changes in phospholipid mass and phospholipid fatty acid composition were extremely limited. Importantly, suppression of postnatal ethanol consumption was not sufficient to reverse the large increase in cholesterol observed in the adult rats.

Modulation of fatty acid composition in murine brain by dietary unsaturated fats

The response of individual phospholipid class fatty acid composition to dietary fats was studied in murine brain. Purified diets containing 10% (by weight) safflower oil, olive oil, linseed oil, or a mix of 9:1 (wt/wt) fish oil/safflower oil were fed to female mice. Offspring continued on the diets and were sacrificed on 3, 18, and 42 days after parturition. Docosahexaenoic acid (DHA;22:6n-3), abundant in the fish oil fed group, was particularly enriched in phosphatidyl ethanolamine and phosphatidyl serine. Fish oil-fed mice accumulated more DHA than the linseed oil-fed mice. While olive oil contained just 0.6% n-3 PUFA, DHA levels in linseed oil-fed animals overall were only slightly higher than olive oil-fed mice and were only elevated in the phospholipids classes phosphatidyl ethanolamine and phosphatidyl inositol. By contrast, DHA levels in the safflower oil-fed group were dramatically lower, containing instead elevated levels of 22:4n-6 and 22:5n-6. Eicosapentaenoic acid (EPA; 20:5n-3) levels were significantly lower in the brain relative to the other tissues we examined, implying that this fatty acid was selectively excluded from the brain or immediately metabolized to DHA in the brain. The amount of EPA in the brain was independent of the form of n-3 fatty acids in the diet, whereas DHA levels were strongly dependent. The type of n-3 PUFA was more important to 22:6n-3 accumulation in brain than the absolute quantity of 18:3n-3 and the vast majority of n-3 accumulation in all lipid classes examined occurred prior to weaning.