[Mammary epithelial cells from women synthetize omega-3 and 6 fatty acids]

The metabolic regulation for the synthesis of human milk (HM) long-chain polyunsaturated fatty acids (LC-PUFAs) omega-3 and omega-6 is poorly known; it is due to the limitations in obtaining breast tissue.

To determine whether the epithelial cells of human breast tissue (ECHBT) express the enzymes that synthesize LC-PUFAs, and to analyze the expression changes in the different types of HM and its correlation with the percentage of LC-PUFAs.

In colostrum, transition and mature HM of 6 women, the fatty acid composition was analyzed by gas chromatography and the mRNA expression of the desaturases δ5D, δ6D and elongase Elovl-5 in the ECHBT was analyzed by qPCR.

tissue express the mRNA of δ5D, δ6D and Elovl-5 for the synthesis of LC-PUFAs, this expression increases in mature milk with respect to colostrum. The percentage of linoleic and alpha-linolenic acid is the similar in the three types of milk, while that of arachidonic acid and docosahexaenoic acid decreased (8% and 14% respectively) in mature milk compared to colostrum. The mRNA of δ5D, δ6D correlated with the percentage of arachidonic acid, that of δ6D and Elovl-5 correlated with the percentage of docosahexaenoic acid (DHA).

The ECHBT express the enzymes that synthesize LC-PUFAs and their expression increases in mature milk, to meet the demand of the newborn. This demonstrates the role of the mammary gland in the synthesis of LC-PUFAs omega-3, such as eicosapentaenoic acid and DHA, essential for neuronal and retinal development of the newborn.