Amelioration of disease progression and oxylipin abnormalities in pcy mouse kidneys by dietary flax oil demonstrates that alpha linolenic acid can be sufficiently converted to docosahexaenoic acid (DHA) to maintain DHA oxylipins levels

Frequent claims are made regarding the apparent inability of the body to convert alpha linolenic acid (ALA) to significant amounts of docosahexaenoic acid (DHA). However, recent labelling studies indicate that the conversion of ALA to DHA in the body is sufficient to supply brain needs for DHA. Another way to assess the ability of ALA to be converted to DHA is to examine whether oxylipin metabolites can be maintained via ALA feeding. Studies in the pcy mouse model of adolescent nephronophthisis have shown that dietary flax containing ALA reduces disease progression. Therefore, to examine the role of renal oxylipins in disease and the effect of flax oil on these, normal and pcy weanling mice were given control diets containing soybean oil (AIN 93G diet), and another pcy group was given the same diet but with flax oil replacing soybean oil. After 20 week flax oil feeding resulted in accumulation of n3 fatty acids and reduced renal fibrosis in diseased kidneys. Flax oil feeding also mitigated the elevated cyclooxygenase derived oxylipins formed from arachidonic acid that occurred in diseased kidneys. Lipoxygenase and cytochrome P450 derived oxylipins were lower in diseased kidneys, and flax oil counteracted some of these reductions, resulting in higher levels of those formed from ALA, eicosapentaenoic acid and DHA. Dietary flax oil did not increase the DHA levels in diseased kidneys, but oxylipins derived from DHA, which were reduced in the diseased kidneys, were restored to normal values by flax oil feeding, indicating that ALA was being converted to DHA at levels sufficient to restore DHA oxylipins levels. These findings indicate that dietary flax oil may reduce disease progression in this model via beneficial changes in oxylipins, and provides further evidence of the ability of ALA to be converted to DHA in physiologically relevant amounts. (Authors abstract)