Abstract
In the present study, we used a preclinical model of induced lipolytic enzyme insufficiency, and hypothesized that the use of monoacylglycerols (MAG) will enhance their bioavailability and delivery to the tissues. Experimental diets containing 20% lipids were fed to rats for 21 days with or without Orlistat. The control diet of fish oil (FO), a source of EPA and DHA, was tested against: structured (A) vanillin acetal of sn-2 MAG (Vanil + O) and (B) diacetyl derivative of sn-2 MAG (Acetyl + O) and (C) free MAG (MAG + O). FA profiles with an emphasis on EPA and DHA levels were determined in plasma, red blood cells (RBC), liver, spleen, brain and retina. We observed significant reduction of lipid absorption when rats co-consumed Orlistat. As expected, the FO groups with and without Orlistat showed the biggest difference. The Vanil + O, Acetyl + O and MAG + O groups, demonstrated higher levels of EPA (5.5 ± 1.9, 4.6 ± 1.6 and 5.6 ± 0.6, respectively) in RBC compared with FO + O diets (3.3 ± 0.2, 2.6 ± 0.2). Levels of EPA incorporation, in plasma, were similar to those obtained for RBC, and similar trends were observed for the collected tissues and even with DHA levels. These observations with two MAG derivatives providing the fatty acid esterified in the sn-2 position, show that these molecules are efficient vehicles of EPA in malabsorption conditions which is in line with our hypothesis. Free MAG, characterized as having exclusively sn-1(3) isomers of EPA, demonstrated better absorption efficiencies and accretion to tissues when compared to structured MAG. The study demonstrated that structured and free MAG can be used efficiently as an enteral vehicle to supply bioactive fatty acids such as EPA and DHA in lipid malabsorption where diminished lipolytic activity is the underlying cause.
Highlights
Defects in either intraluminal lipid digestion or uptake and transport of its digestive products across the gut barrier may lead to lipid malabsorption [1,2]
When groups were compared with changes obtained in group fish oil (FO) + O, no significant differences were observed except for body weight of the Acetyl + O group which was higher through time not significantly different at day 20 (P = 0.0163, Table 2)
Comparison of the data obtained in rats fed FO or FO + O diets demonstrates the efficiency of Orlistat to lower lipid absorption (−44.8% intake reduction), and the consistency of the experimental approach
Summary
Defects in either intraluminal lipid digestion or uptake and transport of its digestive products across the gut barrier may lead to lipid malabsorption [1,2]. Lipid malabsorption is well recognized by steatorrhea and may bear severe consequences if the enzymatic activity in the upper intestine drops below 10% of what is considered normal [2,3]. Another example is cystic fibrosis, an autosomal recessive genetic disorder affecting multiple organ systems, most critically the lungs. It has been suggested that this type of persistent malabsorption is due to insufficient enzymes and due to incomplete intraluminal solubilization or reduced enterocyte uptake, or both [2] Another clinical scenario of lipid malabsorption is observed after intestinal surgeries. These FA are precursors to other biologically important LC-PUFA such as arachidonic acid (ARA, 20:4 n-6), eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) that are proposed to have multiple benefits
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