Dysfonction peroxysomiale associée à la déficience en acides gras essentiels

Abstract

Peroxisomes are intracellular organelles responsible for several essential metabolic functions. Peroxisomal dysfunction may be secondary to defects in the biogenesis and/or assembly of peroxisomes, but it may also be secondary to metabolic disorders. Having shown that nearly half of our pediatric Cystic Fibrosis (CF) population had biochemical evidence of essential fatty acid (EFA) deficiency, we then noted from the phospholipid analysis of red cells an increase in very long chain fatty acids as as a decrease in plasmalogens, two markers suggestive of a disorder in the integrity of peroxisomes. These results then led us to create an EFA deficient animal model which enabled us to reproduce these indices of peroxisomal dysfunction. Finally, beta-carotene supplementation (15 mg t.i.d.) in twelve CF patients, not only corrected lipid peroxidation, secondary to an imbalance between pro- and anti-oxydants but also peroxisomal function while improving the EFA status. These data raise the hypothesis that lipid peroxidation may be in part responsible for EFA deficiency and may lead to peroxisomal dysfunction. The understanding of these mechanisms has important clinical implications since it may lead to new therapeutic strategies.