Enhanced incorporation of dietary DHA into lymph phospholipids by altering its molecular carrier.
Subbaiah Papasani V,Dammanahalli Karigowda J,Yang Peng,Bi Jian,O'Donnell J Michael
Biochimica et biophysica acta
Several previous studies indicated that for optimal uptake by the brain, docosahexaenoic acid (DHA) should be present as phospholipid in the plasma. However most of dietary DHA is absorbed as triacylglycerol (TAG) because it is released as free fatty acid during digestion of either TAG-DHA (fish oil) or sn-2-DHA phospholipid (krill oil), and subsequently incorporated into TAG of chylomicrons. We tested the hypothesis that the absorption of DHA as phospholipid can be increased if it is present in the sn-1 position of dietary phospholipid or in lysophosphatidylcholine (LPC), because it would escape the hydrolysis by pancreatic phospholipase A2. We infused micelle containing the DHA either as LPC or as free acid, into the duodenum of lymph cannulated rats, and analyzed the chylomicrons and HDL of the lymph for the DHA-containing lipids. The results show that while the total amount of DHA absorbed was comparable from the two types of micelle, the percentage of DHA recovered in lymph phospholipids was 5 times greater with LPC-DHA, compared to free DHA. Furthermore, the amount of DHA recovered in lymph HDL was increased by 2-fold when LPC-DHA micelle was infused. These results could potentially lead to a novel strategy to increase brain DHA levels through the diet.
Rate of acyl migration in lysophosphatidylcholine (LPC) is dependent upon the nature of the acyl group. Greater stability of sn-2 docosahexaenoyl LPC compared to the more saturated LPC species.
Sugasini Dhavamani,Subbaiah Papasani V
Several previous studies reported that sn-2 acyl lysophosphatidylcholines (LPCs) undergo rapid isomerization due to acyl migration, especially at physiological pH and temperature. However, these studies have been carried out using mostly sn-2 palmitoyl LPC, whereas the naturally occurring sn-2 LPCs are predominantly unsaturated. In this study, we investigated the acyl migration in four naturally occurring sn-2 acyl LPCs (sn-2 16:0, sn-2 18:1, sn-2 20:4, and sn-2 22:6) stored at various temperatures in aqueous or organic solvents, employing LC/MS to analyze the isomer composition. At 37°C and pH 7.4, the order of acyl migration rates (from sn-2 to sn-1) in aqueous buffer was 16:0 LPC> 18:1 LPC> 20:4 LPC> 22:6 LPC. The rate of isomerization of sn-2 16:0 LPC was 2-5 times greater than that of sn-2 22:6 under these conditions. Complexing the LPCs to serum albumin accelerated the acyl migration of all species, but sn-2 22:6 LPC was least affected by the presence of albumin. The migration rates were lower at lower temperatures (22°C, 4°C, and -20°C), but the differences between the LPC species persisted. All the sn-2 acyl LPCs were more stable in organic solvent (chloroform: methanol, 2:1 v/v), but the effect of the acyl groups on acyl migration was evident in the solvent also, at all temperatures. Storage of sn-2 22:6 LPC at -20°C for 4 weeks in the organic solvent resulted in about 10% isomerization, compared to 55% isomerization for sn-2 16:0. These results show that the sn-2 polyunsaturated LPCs can be stored at -20°C or below for several days without appreciable isomerization. Furthermore, they demonstrate that the sn-2 polyunsaturated LPCs generated in vivo are much more stable under physiological conditions than previously assumed.
Efficient Enrichment of Retinal DHA with Dietary Lysophosphatidylcholine-DHA: Potential Application for Retinopathies.
Sugasini Dhavamani,Yalagala Poorna C R,Subbaiah Papasani V
Although decreased retinal docosahexaenoic acid (DHA) is a known risk factor for retinopathy, currently available omega-3 fatty acid supplements, which are absorbed as triacylglycerol (TAG), do not significantly enrich retinal DHA. We tested the hypothesis that lysophospahtidylcholine (LPC)-DHA which is absorbed as phospholipid, would efficiently increase retinal DHA because of the presence of LPC-specific transporter at the blood-retina barrier. In normal rats, LPC-DHA and di-DHA phosphatidylcholine (PC), which generates LPC-DHA during digestion, increased retinal DHA by 101% and 45%, respectively, but TAG-DHA had no significant effect at the same dose (40 mg/kg, 30 days). In normal mice, both sn-1 DHA LPC and sn-2 DHA LPC increased retinal DHA by 80%, but free DHA had no effect. Lipase-treated krill oil (which contains LPC-DHA and LPC-EPA (eicosapentaenoic acid), but not normal krill oil (which has little LPC), increased both retinal DHA (+76%) and EPA (100-fold). Fish oil, however, had no effect, whether lipase-treated or not. These studies show that retinal DHA can be efficiently increased by dietary LPC-DHA, but not by TAG-DHA or free DHA. Since DHA is known to be protective against retinopathy and other eye diseases, this study provides a novel nutraceutical approach for the prevention/treatment of these diseases.
Effect of supplementation with docosahexaenoic acid ethyl ester and sn-2 docosahexaenyl monoacylglyceride on plasma and erythrocyte fatty acids in rats.
Valenzuela Alfonso,Valenzuela Viviana,Sanhueza Julio,Nieto Susana
Annals of nutrition & metabolism
BACKGROUND/AIMS:Docosahexaenoic acid (C22:6, DHA) is an omega-3 fatty acid required for the normal development of the mammalian nervous and visual system. DHA is provided by the mother during pregnancy and lactating period. Mother's DHA supplementation during pregnancy, and even before pregnancy, has been suggested. DHA can be provided by marine oils, egg's yolk phospholipids, single cell algae oils, the pure fatty acid, or by the ethyl ester derivative (DHA-EE). Another way to provide DHA can be by sn-2 docosahexaenyl monoacylglyceride (DHA-MG), obtained by the treatment of fish oil with stereospecific lipases. sn-2 Fatty acid monoacylglycerides can be more easily absorbed at the intestine than other fatty acid derivatives. METHODS:Female rats fed with a synthetic, which provided essentially no DHA, received a 40-day supplementation of either DHA-EE or DHA-MG. Plasma and erythrocyte fatty acid composition were assessed by gas chromatography at day 0 and 40 of supplementation. RESULTS:DHA-EE increased plasma and erythrocyte DHA by 15 and 11.9%, respectively, with no modification of arachidonic acid (AA) content. DHA-MG supplementation increased plasma and erythrocyte DHA by 24 and 23.8%, respectively, but reduced AA by 5.5 and 3%, respectively. CONCLUSIONS:We conclude that in the rat, DHA-MG supplementation allows a higher plasma and erythrocyte DHA content than DHA-EE with minor modification of AA content.
Efficient Docosahexaenoic Acid Uptake by the Brain from a Structured Phospholipid.
Hachem Mayssa,Géloën Alain,Van Amanda Lo,Foumaux Baptiste,Fenart Laurence,Gosselet Fabien,Da Silva Pedro,Breton Gildas,Lagarde Michel,Picq Madeleine,Bernoud-Hubac Nathalie
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.
The enrichment of eggs with docosahexaenoic acid and eicosapentaenoic acid through supplementation of the laying hen diet.
Zhao Ying-Cai,Shi Hao-Hao,Wang Cheng-Cheng,Yang Jin-Yue,Xue Chang-Hu,Jiang Xiao-Ming,Chen Gui-Dong,Zhang Tian-Tian,Wang Yu-Ming
The enrichment and transformation of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) enriched phospholipids for eggs deserve attention. The aim of the present study was to elucidate the comparative effects of DHA and EPA enriched phospholipids and triacylglycerols on egg fortification by determining the fatty acid composition of egg yolk after intervention with fish oil (15 g/kg) and krill oil (15 and 30 g/kg) for three consecutive weeks. The results indicated that laying hens could incorporate over 300 mg DHA and EPA into one egg. Greater retention efficiency of DHA and EPA in eggs was observed in fish oil supplementation compared with krill oil at equivalent dietary levels. DHA and EPA were prone to locate at the sn-2 position of phosphatidylcholine. Consequently, fish oil possessed high DHA content and conversion rate, and krill oil could raise the proportion of DHA-containing phospholipids in eggs.
Docosahexaenoic acid regulates the formation of lipid rafts: A unified view from experiment and simulation.
Wassall Stephen R,Leng Xiaoling,Canner Samuel W,Pennington Edward Ross,Kinnun Jacob J,Cavazos Andres T,Dadoo Sahil,Johnson Dylan,Heberle Frederick A,Katsaras John,Shaikh Saame Raza
Biochimica et biophysica acta. Biomembranes
Docosahexaenoic acid (DHA, 22:6) is an n-3 polyunsaturated fatty acid (n-3 PUFA) that influences immunological, metabolic, and neurological responses through complex mechanisms. One structural mechanism by which DHA exerts its biological effects is through its ability to modify the physical organization of plasma membrane signaling assemblies known as sphingomyelin/cholesterol (SM/chol)-enriched lipid rafts. Here we studied how DHA acyl chains esterified in the sn-2 position of phosphatidylcholine (PC) regulate the formation of raft and non-raft domains in mixtures with SM and chol on differing size scales. Coarse grained molecular dynamics simulations showed that 1-palmitoyl-2-docosahexaenoylphosphatylcholine (PDPC) enhances segregation into domains more than the monounsaturated control, 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC). Solid state H NMR and neutron scattering experiments provided direct experimental evidence that substituting PDPC for POPC increases the size of raft-like domains on the nanoscale. Confocal imaging of giant unilamellar vesicles with a non-raft fluorescent probe revealed that POPC had no influence on phase separation in the presence of SM/chol whereas PDPC drove strong domain segregation. Finally, monolayer compression studies suggest that PDPC increases lipid-lipid immiscibility in the presence of SM/chol compared to POPC. Collectively, the data across model systems provide compelling support for the emerging model that DHA acyl chains of PC lipids tune the size of lipid rafts, which has potential implications for signaling networks that rely on the compartmentalization of proteins within and outside of rafts.
The impact of dietary sn-2 palmitic triacylglycerols in combination with docosahexaenoic acid or arachidonic acid on lipid metabolism and host faecal microbiota composition in Sprague Dawley rats.
Wan Jianchun,Hu Songyou,Jacoby Jörg J,Liu Jie,Zhang Yaqiong,Yu Liangli Lucy
Food & function
Sn-2 palmitic acid triacylglycerols (sn2PA fat) and polyunsaturated fatty acids are thought to influence the metabolic status and intestinal bacterial population of the host. In this study, the impact of sn2PA fat in combination with DHA or ARA in the diet on lipid metabolism in the liver and faecal microbiota composition were investigated in rats fed diets containing sn2PA fat, 90% sn2PA fat + 10% DHA oil (wt%), or 90% sn2PA fat + 10% ARA oil (wt%). Tissue fatty acid composition was measured using gas chromatography (GC), whereas the faecal microbial composition was assessed using 16S rRNA high-throughput sequencing technology. In addition, faecal short-chain fatty acids (SCFA) were analyzed using ion chromatography. The results showed that sn2PA fat in combination with DHA or ARA significantly reduced liver triacylglyceride (TG) content compared with the sn2PA fat only group. Moreover, the supplementation with sn2PA fat in combination with DHA or ARA significantly promoted the growth of Lactobacillus in the feces at the genus level. On the other hand, the growth of the opportunistic pathogen Desulfovibrio was significantly inhibited by sn2PA fat in combination with ARA compared with the sn2PA fat group. In addition, sn2PA fat in combination with DHA or ARA significantly increased total SCFA concentration in the faeces, suggesting a beneficial effect on host intestinal health.
Bioavailability of docosahexaenoic acid 22:6(n-3) from enantiopure triacylglycerols and their regioisomeric counterpart in rats.
Linderborg Kaisa M,Kulkarni Amruta,Zhao Ai,Zhang Jian,Kallio Heikki,Magnusson Johann D,Haraldsson Gudmundur G,Zhang Yumei,Yang Baoru
Lack of synthetic enantiospecific triacylglycerols (TAGs) has hindered our understanding of the impact of TAG structure on the absorption and metabolic fate of fatty acids (FAs). In a five-day feeding trial with mildly (n-3) deficient rats, the bioavailability of docosahexaenoic acid [22:6(n-3), DHA] and stearic acid (18:0) from the two different enantiomers of TAG: sn-22:6(n-3)-18:0-18:0 and sn-18:0-18:0-22:6(n-3), and their regioisomeric TAG: sn-18:0-22:6(n-3)-18:0 was compared. Less secretion of fecal DHA was detected from the sn-2 position compared with the sn-1 and sn-3 positions, but no difference was found in DHA content of the fasting plasma or in the weight of the body or organs. 18:0 was lost to feces mainly as cleaved from the primary positions but also as glycerol-bound. The 5-day intervention in rats was long enough to modify the fatty acid profile of plasma phospholipids.
Enrichment of brain docosahexaenoic acid (DHA) is highly dependent upon the molecular carrier of dietary DHA: lysophosphatidylcholine is more efficient than either phosphatidylcholine or triacylglycerol.
Sugasini Dhavamani,Yalagala Poorna C R,Goggin Alexis,Tai Leon M,Subbaiah Papasani V
The Journal of nutritional biochemistry
Docosahexaenoic acid (DHA) is highly concentrated in the brain, and its deficiency is associated with several neurological disorders including Alzheimer's disease. However, the currently used supplements do not appreciably enrich brain DHA, although they enrich most other tissues. We tested the hypothesis that the ability of the dietary carrier to augment brain DHA depends upon the generation of DHA-lysophosphatidylcholine (LPC), the preferred carrier of DHA across the blood brain barrier. We compared the efficacy of DHA-triacylglycerol (TAG), di-DHA phosphatidylcholine (PC) and DHA-LPC to enrich brain DHA following their gavage to normal rats for 30 days, all at a dose of 10 mg DHA/day. The results show that DHA from TAG, which is released as free DHA or monoacylglycerol during digestion and is absorbed as TAG in chylomicrons, was incorporated preferentially into adipose tissue and heart but not into brain. In contrast, LPC-DHA increased brain DHA by up to 100% but had no effect on adipose tissue. Di-DHA PC, which generates both free DHA and LPC-DHA during the digestion, enriched DHA in brain, as well as in heart and liver. Brain-derived neurotrophic factor was increased by di-DHA PC and DHA-LPC, but not by TAG-DHA, showing that enrichment of brain DHA correlated with its functional effect. We conclude that dietary DHA from TAG or from natural PC (sn-2 position) is not suitable for brain enrichment, whereas DHA from LPC (at either sn-1 or sn-2 position) or from sn-1 position of PC efficiently enriches the brain and is functionally effective.
Docosahexaenoic acid at the sn-2 position of structured triacylglycerols improved n-3 polyunsaturated fatty acid assimilation in tissues of hamsters.
Bandarra Narcisa M,Lopes Paula A,Martins Susana V,Ferreira Júlia,Alfaia Cristina M,Rolo Eva A,Correia Jorge J,Pinto Rui M A,Ramos-Bueno Rebeca P,Batista Irineu,Prates José A M,Guil-Guerrero José L
Nutrition research (New York, N.Y.)
In this study, we hypothesized that the incorporation of docosahexaenoic acid (DHA) in tissues will be higher when it is ingested as triacylglycerols (TAG) structured at the sn-2 position, which enhances efficacy and health benefits of dietary DHA n-3 supplementation. Ten-week-old Golden Syrian male hamsters were randomly allocated into 4 dietary groups with 10 animals in each: linseed oil (LSO; control group), fish oil (FO), fish oil ethyl esters (FO-EE), and structured DHA at the sn-2 position of TAG (DHA-SL). After 12 weeks, there were no variations in the hamsters' body composition parameters across dietary groups. The DHA-SL diet had the lowest values of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total lipids, and aspartate aminotransferase activity, whereas the inverse was observed for the FO diet. Glucose was increased in the LSO diet without affecting insulin and insulin resistance markers. Whereas n-3 polyunsaturated fatty acid was increased in the brain of hamsters fed the DHA-SL diet, higher levels of n-6 polyunsaturated fatty acid were observed in the liver and erythrocytes of the LSO. The highest omega-3 index was obtained with the DHA-SL diet. The principal component analyses discriminated DHA from other metabolites and set apart 4 clusters matching the 4 diets. Similarly, liver, erythrocytes, and brain were separated from each other, pointing toward an individual signature on fatty acid deposition. The structured sn-2 position DHA-containing TAG ameliorated blood lipids and fatty acid incorporation, in particular eicosapentaenoic acid and DHA in liver, erythrocytes, and brain, relative to commercially FOs, thus improving the health benefits of DHA due to its higher bioavailability.
Docosahexaenoic acid (DHA) at the sn-2 position of triacylglycerols increases DHA incorporation in brown, but not in white adipose tissue, of hamsters.
Lopes Paula A,Bandarra Narcisa M,Martins Susana V,Madeira Marta S,Ferreira Júlia,Guil-Guerrero José L,Prates José A M
International journal of food sciences and nutrition
We hypothesised that the incorporation of docosahexaenoic acid (DHA) across adipose tissues will be higher when it is ingested as triacylglycerols (TAG) structured at the sn-2 position. Ten-week old male hamsters were allocated to 4 dietary treatments (n = 10): linseed oil (LSO-control group), fish oil (FO), fish oil ethyl esters (FO-EE) and structured DHA at the sn-2 position of TAG (DHA-SL) during 12 weeks. In opposition to the large variations found for fatty acid composition in retroperitoneal white adipose tissue (WAT), brown adipose tissue (BAT) was less responsive to diets. DHA was not found in subcutaneous and retroperitoneal WAT depots but it was successfully incorporated in BAT reaching the highest percentage in DHA-SL. The PCA on plasma hormones (insulin, leptin, adiponectin) and fatty acids discriminated BAT from WATs pointing towards an individual signature on fatty acid deposition, but did not allow for full discrimination of dietary treatments within each adipose tissue.