Recent advances in brain polyunsaturated fatty acid metabolism:  Metabolism, signalling and a bit of nutrition.

Dr. Richard Bazinet

University of Toronto, Canada

 

The brain is especially enriched with the polyunsaturated fatty acids (PUFA) docosahexaenoic acid (DHA) and arachidonic acid, while being virtually devoid of other PUFA such as eicosapentaenoic acid (EPA).  It has been suggested that the plasma supply to the brain regulates brain PUFA levels and replaces PUFA consumed in the brain.     Upon presenting evidence that the plasma unesterified pool is a major source of brain PUFA, especially for DHA.  Interestingly, EPA is barely detectable in the brain, but is hypothesized to be protective in Major Depression.  Upon reviewing the key evidence supporting this claim, I will describe recent studies from our lab demonstrating, in rodents, how EPA rapidly enters the brain but is subjected to metabolism which regulates its low levels.  The implication of these results for its therapeutic mechanism of action will be discussed.  Because fatty acid uptake into the brain can be imaged in humans, we can now, for the first time, estimate brain PUFA, including DHA, requirements.  I will then examine recent advances in PUFA signalling, especially in the context of neuroinflammation, in the brain that may relate to their mechanism of action.