In Vivo Absorption and Lymphatic Bioavailability of Docosahexaenoic Acid from Microalgal Oil According to Its Physical and Chemical Form of Vectorization.

Docosahexaenoic acid (DHA) is an essential fatty acid (FA) with proven pro-health effects, but improving its bioavailability is becoming a public health issue. The bioavailability of DHA from microalgal (A) oil has been comprehensively assessed, particularly in terms of the molecular structuring capabilities offered by A-oil. Here, we explored the impact of five DHA-rich formulas differing in terms of (i) molecular structure, i.e., ethyl ester (EE), monoglyceride (MG), or triglyceride (TG), and (ii) supramolecular form, i.e., emulsified TG or TG + phospholipids (PL blend) on the lymphatic kinetics of DHA absorption and the lipid characteristics of the resulting lipoproteins. We demonstrated in rats that the conventional A-DHA TG structure afforded more effective DHA absorption than the EE structure (+23%). Furthermore, the A-DHA MG and A-DHA emulsions were the better DHA vectors (AUC: 89% and +42%, respectively) due to improved lipolysis. The A-DHA MG and A-DHA emulsion presented the richest DHA content in TG (+40%) and PL (+50%) of lymphatic chylomicrons, which could affect the metabolic fate of DHA. We concluded that structuring A-DHA in TG or EE form would better serve for tissue and hepatic metabolism whereas A-DHA in MG and emulsion form could better target nerve tissues.

Efficient Docosahexaenoic Acid Uptake by the Brain from a Structured Phospholipid.

Docosahexaenoic acid (DHA) is the main essential omega-3 fatty acid in brain tissues required for normal brain development and function. An alteration of brain DHA in neurodegenerative diseases such as Alzheimer's and Parkinson's is observed. Targeted intake of DHA to the brain could compensate for these deficiencies. Blood DHA is transported across the blood-brain barrier more efficiently when esterified at the sn-2 position of lyso-phosphatidylcholine. We used a structured phosphatidylcholine to mimic 2-docosahexaenoyl-lysoPC (lysoPC-DHA), named AceDoPC (1-acetyl,2-docosahexaenoyl-glycerophosphocholine), that may be considered as a stabilized form of the physiological lysoPC-DHA and that is neuroprotective in experimental ischemic stroke. The aim of the present study was to investigate whether AceDoPC is a relevant delivery form of DHA to the brain in comparison with other forms of the fatty acid. By combining in vitro and in vivo experiments, our findings report for the first time that AceDoPC is a privileged and specific carrier of DHA to the brain, when compared with DHA-containing PC and non-esterified DHA. We also show that AceDoPC was hydrolyzed, in part, into lysoPC-DHA. Ex vivo autoradiography of rat brain reveals that DHA from AceDoPC was localized in specific brain regions playing key roles in memory, thoughts, and cognitive functions. Finally, using molecular modeling approaches, we demonstrate that electrostatic and lipophilic potentials are distributed very similarly at the surfaces of AceDoPC and lysoPC-DHA. Our findings identify AceDoPC as an efficient way to specifically target DHA to the brain, which would allow potential preventive and therapeutic approaches for neurological diseases.