Docosahexaenoic Acid Formation Research Articles

Supplementary n-3 fatty acids sources on performance and formation of omega-3 in egg of laying hens: a meta-analysis

A meta-analysis was performed to evaluate the effects of supplementary n-3 polyunsaturated fatty acids (PUFA) sources in the diet on the formation of some important n-3 PUFA contents in eggs and to assess factors contributing to the conversion efficiency of omega-3 in laying hens. A dataset was constructed from 34 studies examining the impact of dietary inclusion with ingredients rich in n-3 PUFA on fatty acids profile and production performance of laying hens. The eligibility criteria were developed to obtain studies reporting required information with sufficient quality. The mixed model methodology was employed where the “study” was set as random effects and fatty acid (FA) supplements as fixed effects. Several factors were included in the models as covariates. Discrete analysis for sources of FA was also performed to compare their effects on FA formation in eggs. Significant linear positive associations were observed between the concentration of α-linolenic acid (ALA), total n-3 PUFA, and the ratio of linoleic acid (LA) to ALA (LA/ALA) in diets with the formation of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), total n-3 PUFA, and n6/n3 ratio in egg (P < 0.05) with different magnitudes. ALA and total n-3 PUFAs concentration had no relationship with cholesterol concentration, feed intake, and egg weight. Prediction models for DHA formation was higher for ALA as predictor variables (slope = 0.482; R2 = 0.684) than n-3 PUFAs (slopes = 0.998, R2 = 0.628). Significant interactions were found on the level of ALA × FA sources and n-3 PUFA × FA sources. Fish oil (P = 0.0148, R2 = 0.732) improved the prediction equation to estimate DHA formation. To conclude, levels of ALA, n-3 PUFA, and the ratio of LA/ALA can be used as predictor variables to estimate the formation of n-3 fatty acids in eggs. It was confirmed that although all n-3 FA sources had a positive correlation on DHA and n-3 PUFA deposition, however, fish oil showed the highest prediction model for DHA formation across all FA sources included in the dataset.

Lipid mediator profiles of burn wound healing: Acellular cod fish skin grafts promote the formation of EPA and DHA derived lipid mediators following seven days of treatment

The use of acellular fish skin grafts (FSG) for the treatment of burn wounds is becoming more common due to its beneficial wound healing properties. In our previous study we demonstarted that FSG is a scaffold biomaterial that is rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) conjugated to phosphatidylcholines. Here we investigated whether EPA and DHA derived lipid mediators are influenced during the healing of burn wounds treated with FSG. Deep partial and full thickness burn wounds (DPT and FT, respectively) were created on Yorkshire pigs (n = 4). DPT were treated with either FSG or fetal bovine dermis while FT were treated either with FSG or cadaver skin initially and followed by a split thickness skin graft. Punch biopsies were collected on days 7, 14, 21, 28 and 60 and analyzed in respect of changes to approximately 45 derivatives of EPA, DHA, arachidonic acid (AA), and linoleic acid (LA) employing UPLC-MS/MS methodology. Nine EPA and DHA lipid mediators, principally mono-hydroxylated derivatives such as 18-HEPE and 17-HDHA, were significantly higher on day 7 in the DPT when treated with FSG. A similar but non-significant trend was observed for the FT. The results suggest that the use of FSG in burn wound treatment can alter the formation of EPA and DHA mono hydroxylated lipid mediators in comparison to other grafts of mammalian origin. The differences observed during the first seven days after treatment indicates that FSG affects the early stages of wound healing.

Taxonomy and Physiology of Oxyrrhis marina and Oxyrrhis maritima in Korean Waters

The genus Oxyrrhis is a heterotrophic dinoflagellate found in diverse marine environments. Oxyrrhis spp. have received attention owing to their ecological and industrial importance, high lipid contents, and docosahexaenoic acid formation. To the best of our knowledge, contrary to O. marina, ecophysiological characterization studies on O. maritima have not yet been reported. Therefore, we investigated the taxonomy and ecophysiology of four strains of O. marina from coastal waters and two strains of O. maritima from the littoral tidepool waters of Korea. Based on phylogenetic trees constructed using internal transcribed spacer ribosomal DNA (ITS rDNA) and SSU rDNA of dinoflagellates, the clade of all four O. marina strains was divergent from that of the two O. maritima strains. We measured the growth rates of both species at various water temperatures (10–36 °C), salinities (5–90), and light intensities (0–100 µE·m−2·s−1). The lowest (O. marina and O. maritima: 10 °C) and highest temperatures (O. marina: &lt;35 °C, O. maritima: &gt;35 °C) revealed that O. maritima has more tolerance to high salinity. This study provides a basis for understanding the ecophysiology of O. marina and O. maritima and their population dynamics in marine ecosystems.

Novel n-3 Docosapentaneoic Acid-Derived Pro-resolving Mediators Are Vasculoprotective and Mediate the Actions of Statins in Controlling Inflammation.

Inflammation is a fundamentally protective process that guards the host from invading pathogens and is central in the repair and regeneration of damaged tissue. However, when uncontrolled, the overzealous response leads to tissue damage and malaise. Indeed, this process is now appreciated to be at the center of many chronic inflammatory diseases including vascular disease and arthritis. Studies investigating the mechanisms through which acute inflammation is actively turned off allowingtissues to regain function demonstrated that the essential fatty acids, arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are enzymatically converted to bioactive mediators. These autacoidscarry distinct structuresand biological actions, actively reprogramming the inflammatory reaction to promote its terminationby counter-regulating the production of pro-inflammatory mediators and regulate leukocyte trafficking as well as phenotype. Recently we found that n-3 docosapentaenoic acid (DPA), which was until then only regarded as a biosynthetic intermediate in the formation of DHA from EPA, is also converted to structurally distinct bioactive mediators that reprogram the host immune response. In the present review we will discuss the evidence underpinning the biological actions of these novel n-3 DPA-derived autacoids in particular as they pertain to the vascular system.

Abstract 2224: Increased 15-lipoxygenase-1 activity limits tumor development in the azoxymethane mouse model of colon cancer: impact of omega-3-acid ethyl esters

Abstract Pro-inflammatory signaling has been shown to promote colorectal tumorigenesis and is a target for the development of effective chemopreventive approaches. The specialized pro-resolving lipid mediators (SPMs, e.g. resolvins), bioactive metabolites of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), actively terminate inflammation and have been proposed to possibly contribute to the anti-tumorigenic effects of DHA and EPA. The enzyme 15-lipoxygenase-1 (ALOX15) is a key biosynthetic enzyme in generation of resolvins. However, 15-LOX-1 expression is commonly lost during human CRC tumorigenesis starting in premalignant stages via transcriptional mechanisms independent of substrate availability. The impact of ALOX15 on DHA and EPA’s effects on tumorigenesis remain unknown. Mice with intestinal epithelium-specific expression of human ALOX15 (15-LOX-1-gut mice) and wild-type FVB controls were injected with azoxymethane (AOM, 7.5mg/kg) once weekly for 6w and followed for 20w. Mice were fed diet with 1% omega-3-acid ethyl esters (O3AEE, a pharmaceutical grade fish oil preparation of EPA and DHA ethyl esters) or control diet starting 3w before initiation with AOM. Colonic tumors developed in 10 of the 13 (77%) wild type (WT) mice fed control diet, 5 of the 10 (50%) WT mice fed O3AEE diet, 5 of the 12 (42%) 15-LOX-1-gut mice fed control diet, and 3 of the 10 (30%) 15-LOX-1-gut mice fed control diet. Lipid mediator levels were measured by liquid chromatography/ tandem mass spectrometry (LC-MS/MS). The SPMs resolvin E1 and D2 (RvE1, RvD2) as well as the pathway intermediates 18-HEPE and 17-HDHE were increased in ALOX15-gut mice on O3AEE (see Table; data are shown as ng/mg protein; mean ± SEM). Our results demonstrate that ALOX15 activity is important to DHA and EPA formation of resolvins and inhibition of colonic tumorigenesis. Supported by grants CPRIT RP150195 and NIH RO1 R01CA195686 SPMs in O3AEE or control diet fed miceWTWT15-LOX-1-gut15-LOX-1-gutControl dietO3AEE dietControl dietO3AEE diet18-HEPE00.46 + 0.500.82 + 0.3117-HDHE0.21 + 0.090.2 + 0.74.2 + 0.4113.35 + 3.1RvE10001.98 + 0.77RvD200.024 + 0.0240.17 + 0.0220.3 + 0.077 Citation Format: Xiangsheng Zuo, Jennifer K. Colby, Fuyao Liu, Shen Gao, Ling Wu, Jonathan C. Jaoude, Micheline J. Moussalli, Lin Tan, Peiying Yang, Imad Shureiqi. Increased 15-lipoxygenase-1 activity limits tumor development in the azoxymethane mouse model of colon cancer: impact of omega-3-acid ethyl esters [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2224. doi:10.1158/1538-7445.AM2017-2224

Curcumin and linseed oil co-delivered in phospholipid nanoemulsions enhances the levels of docosahexaenoic acid in serum and tissue lipids of rats

Docosahexaenoic acid (DHA) is an important long chain omega-3 polyunsaturated fatty acid (PUFA) primarily found in marine fishes. The diets of vegetarian population do not contain preformed DHA, but they can derive it from shorter chain α-linolenic acid (ALA) found in plant oils. However, the conversion efficiency of ALA to DHA is minimal in human adults. This may cause insufficiency of DHA in the vegetarian population. Curcumin, diferuloyl methane found in the spice turmeric, has the potential to increase the formation of DHA from ALA by activating the enzymes FADS2 and elongase 2. The present study was designed to prepare curcumin nanoemulsion using phospholipid core material (Lipoid™) and exploring the possibility of enhancing its bioavailability and its impact on DHA levels in rats. Curcumin was dissolved in coconut oil (CNO, MCFA rich), Sunflower oil (SNO, n-6 PUFA rich) or Linseed oil (LSO, n-3 PUFA rich) and nanoemulsions were prepared after mixing with Lipoid™ using high pressure homogenizer. The nanoemulsions were fed to weaning rats for 60 days along with AIN-93 diets. Rats fed nanoemulsion containing curcumin in LSO showed high levels of curcumin in serum liver, heart and brain. Significant increase in DHA levels of serum and tissue lipids were observed in rats given LSO with curcumin in nanoemulsions. Therefore, supplementation of diets with ALA rich LSO and curcumin could increase DHA concentrations in serum, liver, heart and brain lipids which have implications for meeting the DHA requirements of vegetarian populations.

Effect of cerulenin on fatty acid composition and gene expression pattern of DHA-producing strain Colwellia psychrerythraea strain 34H.

BackgroundColwellia psychrerythraea 34H is a psychrophilic bacterium able to produce docosahexaenoic acid (DHA). Polyketide synthase pathway is assumed to be responsible for DHA production in marine bacteria.ResultsFive pfa genes from strain 34H were confirmed to be responsible for DHA formation by heterogeneous expression in Escherichia coli. The complexity of fatty acid profile of this strain was revealed by GC and GC–MS. Treatment of cells with cerulenin resulted in significantly reduced level of C16 monounsaturated fatty acid (C16:1Δ9t, C16:1Δ7). In contrast, the amount of saturated fatty acids (C10:0, C12:0, C14:0), hydroxyl fatty acids (3-OH C10:0 and 3-OH C12:0), as well as C20:4ω3, C20:5ω3 and C22:6ω3 were increased. RNA sequencing (RNA-Seq) revealed the altered gene expression pattern when C. psychrerythraea cells were treated with cerulenin. Genes involved in polyketide synthase pathway and fatty acid biosynthesis pathway were not obviously affected by cerulenin treatment. In contrast, several genes involved in fatty acid degradation or β-oxidation pathway were dramatically reduced at the transcriptional level.ConclusionsGenes responsible for DHA formation in C. psychrerythraea was first cloned and characterized. We revealed the complexity of fatty acid profile in this DHA-producing strain. Cerulenin could substantially change the fatty acid composition by affecting the fatty acid degradation at transcriptional level. Acyl-CoA dehydrogenase gene family involved in the first step of β-oxidation pathway may be important to the selectivity of degraded fatty acids. In addition, inhibition of FabB protein by cerulenin may lead to the accumulation of malonyl-CoA, which is the substrate for DHA formation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-016-0431-9) contains supplementary material, which is available to authorized users.

DHA Effects in Brain Development and Function.

Docosahexaenoic acid (DHA) is a structural constituent of membranes specifically in the central nervous system. Its accumulation in the fetal brain takes place mainly during the last trimester of pregnancy and continues at very high rates up to the end of the second year of life. Since the endogenous formation of DHA seems to be relatively low, DHA intake may contribute to optimal conditions for brain development. We performed a narrative review on research on the associations between DHA levels and brain development and function throughout the lifespan. Data from cell and animal studies justify the indication of DHA in relation to brain function for neuronal cell growth and differentiation as well as in relation to neuronal signaling. Most data from human studies concern the contribution of DHA to optimal visual acuity development. Accumulating data indicate that DHA may have effects on the brain in infancy, and recent studies indicate that the effect of DHA may depend on gender and genotype of genes involved in the endogenous synthesis of DHA. While DHA levels may affect early development, potential effects are also increasingly recognized during childhood and adult life, suggesting a role of DHA in cognitive decline and in relation to major psychiatric disorders.

Role and Progress of DHA Dietary Supply in Brain Development of Maternal and Golden Periods

Docosahexaenoic acid (DHA) is a structural component of membrane cells particularly in the central nervous system (CNS) . DHA accumulation in the fetal brain occurs mainly during the last trimester of gestation and it will increase up to the end of the second year of life. Since the endogenous formation of DHA is relatively low, DHA intake may contribute to optimal brain development. The associations between DHA levels and brain development during the lifespan justify the indication of DHA role in differentiation to brain function for neuronal International Journal of Pharma Research and Health Sciences

Effect of malate on docosahexaenoic acid production from Schizochytrium sp. B4D1

Background: Malate involves in the citrate/malate and transhydrogenase cycles to provide precursors for docosahexaenoic acid (DHA) synthesis. The optimal strategy was investigated for increasing DHA production in Schizochytrium species during fermentation. Results: DHA production increased by 47% and reached 5.51 g/L when 4 g malate/L was added during the rapid lipid accumulation stage in shake-flasks culture. Inducing effects of malate was further investigated through the analysis of three kinetic parameters, including specific cell growth rate (μ), specific glucose consumption rate (q Glu ) and DHA formation rate (q DHA ). DHA concentration was enhanced through a novel fed-batch strategy to a maximum value of 30.7 g/L, giving a yield of 0.103 g DHA/g glucose and a productivity of 284 mg L - 1 h - 1 . Conclusion: A novel malate feeding strategy was developed that enhanced DHA yield and productivity of Schizochytrium species which may offer a desirable method for industrial applications. Normal 0 21 false false false EN-US ZH-CN X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.5pt; mso-bidi-font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-font-kerning:1.0pt; mso-ansi-language:EN-US; mso-fareast-language:ZH-CN;}

Genome Sequence of Schizochytrium sp. CCTCC M209059, an Effective Producer of Docosahexaenoic Acid-Rich Lipids.

Schizochytrium is an effective species for producing omega-3 docosahexaenoic acid (DHA). Here, we report a genome sequence of Schizochytrium sp. CCTCC M209059, which has a genome size of 39.09 Mb. It will provide the genomic basis for further insights into the metabolic and regulatory mechanisms underlying the DHA formation.

Novel 14S,21‐dihydroxy‐docosahexaenoic acid rescues wound healing and associated angiogenesis impaired by acute ethanol intoxication/exposure

Acute ethanol intoxication and exposure (AE) has been known to impair wound healing and associated angiogenesis. Here, we found that AE diminished the formation of novel reparative lipid mediator 14S,21-dihydroxy-docosa-4Z,7Z,10Z,12E,16Z,19Z-hexaenoic acid (14S,21-diHDHA) and its biosynthetic intermediate 14S-hydroxy-DHA (14S-HDHA) from docosahexaenoic acid (DHA) in murine wounds. However, AE did not reduce the formation of DHA and the intermediate 21-HDHA. These results indicate that in the biosynthetic pathways of 14S,21-diHDHA in wounds, AE suppresses the 14S-hydroxy-generating activity of 12-lipoxygenase-like (LOX-like), but does not suppress the 21-hydroxy-generating activity of cytochrome P450 and DHA-generating activities. The AE-suppression of 12-LOX-like activity was further confirmed by the diminished formation of 12-hydroxy-eicosatetraenoic acid in wounds under AE. Supplementing 14S,21-diHDHA to wounds rescued the AE-impaired healing and vascularization. 14S,21-diHDHA restored AE-impaired processes of angiogenesis in vitro: endothelial cell migration, tubulogenesis, and phosphorylation of p38 mitogen-activated protein kinase (MAPK). Taken together, the suppression of 14S,21-diHDHA formation is responsible, at least partially, for the AE-impairment of cutaneous wound healing and angiogenesis. Supplementing 14S,21-diHDHA to compensate its deficit in AE-impaired wounds rescues the healing and angiogenesis. These results provide a novel mechanistic insight for AE-impaired wound healing that involves the necessary roles of 14S,21-diHDHA. They also offer leads for developing 14S,21-diHDHA-related therapeutics to ameliorate AE-impairment of wound healing.

Formation of eicosanoids, E2/D2 isoprostanes, and docosanoids following decapitation-induced ischemia, measured in high-energy-microwaved rat brain

Inflammatory lipid mediators derived from arachidonic acid (AA) and docosahexaenoic acid (DHA) modify the pathophysiology of brain ischemia. The goal of this work was to investigate the formation of eicosanoids and docosanoids generated from AA and DHA, respectively, during no-flow cerebral ischemia. Rats were subjected to head-focused microwave irradiation 5 min following decapitation (complete ischemia) or prior to decapitation (controls). Brain lipids were extracted and analyzed by reverse-phase liquid chromatography-tandem mass spectrometry. After complete ischemia, brain AA, DHA, and docosapentaenoic acid concentrations increased 18-, 5- and 4-fold compared with controls, respectively. Prostaglandin E(2) (PGE(2)) and PGD(2) could not be detected in control microwaved rat brain, suggesting little endogenous PGE(2)/D(2) production in the brain in the absence of experimental manipulation. Concentrations of thromboxane B(2), E(2)/D(2)-isoprostanes, 5-hydroxyeicosatetraenoic acid (5-HETE), 5-oxo-eicosatetraenoic acid, and 12-HETE were significantly elevated in ischemic brains. In addition, DHA products such as mono-, di- and trihydroxy-DHA were detected in control and ischemic brains. Monohydroxy-DHA, identified as 17-hydroxy-DHA and thought to be the immediate precursor of neuroprotectin D(1), was 6.5-fold higher in ischemic than in control brain. The present study demonstrated increased formation of eicosanoids, E(2)/D(2)-IsoPs, and docosanoids following cerebral ischemia. A balance of these lipid mediators may mediate immediate events of ischemic injury and recovery.

Estradiol Favors the Formation of Eicosapentaenoic Acid (20:5n‐3) and n‐3 Docosapentaenoic Acid (22:5n‐3) from Alpha‐Linolenic Acid (18:3n‐3) in SH‐SY5Y Neuroblastoma Cells

Whether neurosteroids regulate the synthesis of long chain polyunsaturated fatty acids in brain cells is unknown. We examined the influence of 17-beta-estradiol (E2) on the capacity of SH-SY5Y cells supplemented with alpha-linolenic acid (ALA), to produce eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). Cells were incubated for 24 or 72 h with ALA added alone or in combination with E2 (ALA + E2). Fatty acids were analyzed by gas chromatography of ethanolamine glycerophospholipids (EtnGpl) and phosphatidylcholine (PtdCho). Incubation for 24 h with ALA alone increased EPA and DPA in EtnGpl, by 330 and 430% compared to controls (P < 0.001) and DHA by only 10% (P < 0.05). Although DHA increased by 30% (P < 0.001) in ALA + E2-treated cells, the difference between the ALA and ALA + E2 treatments were not significant after 24 h (Anova-1, Fisher's test). After 72 h, EPA, DPA and DHA further increased in EtnGpl and PtdCho of cells supplemented with ALA or ALA + E2. Incubation for 72 h with ALA + E2 specifically increased EPA (+34% in EtnGpl, P < 0.001) and DPA (+15%, P < 0.001) compared to ALA alone. Thus, SH-SY5Y cells produced membrane EPA, DPA and DHA from supplemental ALA. The formation of DHA was limited, even in the presence of E2. E2 significantly favored EPA and DPA production in cells grown for 72 h. Enhanced synthesis of ALA-elongation products in neuroblastoma cells treated with E2 supports the hypothesis that neurosteroids could modulate the metabolism of PUFA.

A one-step method of 10,17-dihydro(pero)xydocosahexa-4Z,7Z,11E,13Z,15E,19Z-enoic acid synthesis by soybean lipoxygenase

A product of lipoxygenase (LOX) oxidation of docosahexaenoic acid (DHA), 10,17-dihydro(pero)xydocosahexa-4Z,7Z,11E,13Z,15E,19Z-enoic acid [10,17(S)-diH(P)DHA] was obtained through various reaction pathways that involved DHA, 17(S)-hydro(pero)xydocosahexa-4Z,7Z,11Z,13Z,15E,19Z-enoic acid [17(S)-H(P)DHA], soybean lipoxygenase (sLOX), and potato tuber lipoxygenase (ptLOX) in various combinations. The structure of the product was confirmed by HPLC, ultraviolet (UV) light spectrometry, GC-MS, tandem MS, and NMR spectroscopy. It has been found that 10,17(S)-diH(P)DHA formed by sLOX through direct oxidation of either DHA or 17(S)-H(P)DHA was apparently identical to the product of ptLOX oxidation of the latter. The sLOX- and ptLOX-derived samples of 10,17-diHDHAs coeluted under the conditions of normal, reverse, and chiral phase HPLC analyses, displayed identical UV absorption spectra with maxima at 260, 270, and 280 nm, and had similar one-dimensional and two-dimensional proton NMR spectra. Analysis of their NMR spectra led to the conclusion that 10,17-diHDHA formed by sLOX had solely 11E,13Z,15E configuration of the conjugated triene fragment, which was identical to the previously published structure of its ptLOX-derived counterpart. Based on the cis,trans geometry of the reaction products, the conclusion is made that in the tested conditions sLOX catalyzed direct double dioxygenation of DHA. Compared with the previously described two-enzyme method that involved sLOX and ptLOX, the current simplified one-enzyme procedure uses only sLOX as the catalyst of both dioxygenation steps.

Biomass and docosahexaenoic acid formation by Schizochytrium mangrovei Sk-02 at low salt concentrations

Growth and docosahexaenoic acid (DHA) formation in Schizochytrium mangrovei Sk-02 were studied in yeast extract-glucose (YEG) media supplemented with either artificial sea salts (ASS) or a simplified salts medium consisting of magnesium sulfate and/or sodium chloride. With increasing concentrations of ASS, biomass increased from 9 (no ASS) to a maximum of 21 g l-1 (at 2.1 M ASS or 68 g l-1). Addition of manganese increased these values to 17 (no ASS) and a plateau of 24 g l-1 (at >0.25 M ASS). Replacing ASS with magnesium sulfate and/or sodium chloride and manganese as an additional factor suggested that maximal biomass (24 gl-1) could only be achieved when both magnesium sulfate and manganese were added. As significant carry-over of elements in the inoculum was observed, the latter was washed in further experiments. Addition of an optimal concentration of ca. 5 mM magnesium sulfate to YEG-media then resulted in a maximum biomass level of ca. 24 g l-1 and 5.2 g l-1 DHA in 72 h. Additional supplementation with sodium chloride (8 mM) significantly stimulated biomass formation when magnesium sulfate addition was below 0.8 mM, but not at higher levels of the latter. However, cultivation time was reduced by ca. 24 h, resulting in formation of ca. 5.5 g l-1 DHA in only 48 h. By replacing ASS with magnesium sulfate plus sodium chloride, the sum of the concentration of these four elements in media could be reduced ca. nine-fold, while achieving similar biomass- and DHA-yields. The concentration of chloride, a compound highly corrosive to steel fermenters, was reduced more than ten-fold.

Infants with Intrauterine Growth Restriction Have Impaired Formation of Docosahexaenoic Acid in Early Neonatal Life: A Stable Isotope Study

This study evaluated the arachidonic acid (AA) and docosahexaenoic acid (DHA) formation from d5-labeled linoleic acid (d5-LA) and alpha-linolenic acid (d5-LNA) precursors in infants with intrauterine growth restriction (IUGR) compared with control groups matched by gestational age (GA) or birth weight. We compared DHA and AA formation from deuterated precursors d5-LA and d5-LNA in 11 infants with IUGR with 13 and 25 control subjects who were appropriate for GA and matched by GA and by birth weight, respectively. After an enteral administration of d5-LA and d5-LNA, we determined unlabeled and d5-labeled fatty acids at 24, 48, and 96 h in plasma. Absolute concentrations and area under the curve (AUC) over the 96-h study were used for analysis. Absolute concentration of d5-DHA and the product/precursor ratio of the d5-labeled AUCs indicated a less active DHA formation from LNA in infants with IUGR compared with their GA-matched (2-fold) and birth weight-matched (3-fold) control subjects. The ratios of eicosapentaenoic and n-3 docosapentaenoic acid to DHA were also affected. Similar evaluation for the n-6 series was not significant. DHA metabolism is affected in infants with IUGR; the restricted DPA to DHA conversion step seems to be principally responsible for this finding.

11 Bioequivalence of the Precursors Alfa-Linolenic Acids (LNA) and Eicosapentaenoic Acid (EPA) in the Synthesis of Docosahexaenoic Acid (DHA) Using a Multi-Compartmental Model with Stable Isotope Methodology

Introduction: Docosahexaenoic acid (22:6n3; DHA), an essential fatty acid (EFA), is a major component of the nervous system and is required for optimal neuronal function. Human infants can synthesize DHA from dietary alpha-linolenic acid (18:3n3;LNA) with eicosapentaenoate (20:5n3; EPA) and docosapentaenoate (22:5n3; DPA) as intermediates. It is of interest then to determine whether LNA or its partially metabolized form, EPA, would be a better substrate to support DHA biosynthesis. Previously we have used isotopic ratios to report a higher DHA formation from LNA(x5) compared to EPA.

Long Chain Polyunsaturated Fatty Acid Formation in Neonates: Effect of Gestational Age and Intrauterine Growth

The present study was designed to evaluate the effect of gestational age and intrauterine growth on the long chain polyunsaturated fatty acid (LCP) synthesis from dietary precursors in neonates as reflected by plasma pools. These have been considered conditionally essential nutrients for normal growth, sensory maturation, and neurodevelopment. In vivo elongation/desaturation of deuterated d5-linoleic acid (d5-LA) to form arachidonic acid (AA), and d5-alpha-linolenic acid (d5-LNA) to form docosahexaenoic acid (DHA), was studied in 19 preterm appropriate-for-gestational-age (AGA) infants, 11 AGA term, and 11 intrauterine growth-retarded (IUGR) infants. They received a dose of 50 mg/kg body weight of d5-LA and d5-LNA enterally during the first days of life; d5-labeled derivatized fatty acids were determined in blood samples obtained at 24, 48, and 96 h after dosing. Lipids were extracted and fatty acids analyzed by gas chromatography and negative ion mass spectrometry. Mean concentrations, microg/mL, and d5/d0 for n-3 and n-6 precursor and products were computed at various times and were also integrated over the complete study period. Significantly higher time-integrated concentration of d5-AA and d5-DHA were observed in preterm infants relative to the other two groups. Time-integrated enrichment of DHA relative to LNA was 100-fold lower in preterms, 410-fold lower in term, and 27-fold lower in IUGR infants. Similar significant declines in product to precursor enrichments were noted for the n-6 series. A significant negative correlation of AA and DHA formation based on time-integrated d5/d0 ratios with gestational age was noted; product/ precursor enrichment versus gas chromatography for the n-6 series had an r of -0.5, p = 0.001, and for the n-3 series had an r of -0.6, p = 0.0001. Birth weight or weight adequacy did not add further strength to the relationship. We conclude that LCP formation from deuterated precursors occurs as early as 26 wk gestation, and in fact is more active at earlier gestational ages; growth retardation appears to slow down or diminish LCP formation. No quantitative estimates of LCP synthesis or nutritional sufficiency can be derived from these data.

Docosahexaenoic acid synthesis in human skin fibroblasts involves peroxisomal retroconversion of tetracosahexaenoic acid

The purpose of this study was to determine whether the formation of docosahexaenoic acid in human cells occurs through a pathway that involves 24-carbon n-3 fatty acid intermediates and retroconversion. Normal human skin fibroblasts synthesized radiolabeled docosahexaenoic acid from [1-(14)C]18:3n-3, [3-(14)C]22:5n-3, [3-(14)C]24:5n-3, and [3-(14)C]24:6n-3. The amount of docosahexaenoate formed was reduced in fibroblasts defective in peroxisomal biogenesis, by 90-100% in Zellweger's syndrome and by 50-75% in infantile Refsum's disease. Fatty acid elongation and desaturation were intact in these mutant cells. No decrease in radiolabeled docosahexaenoic acid production occurred in mutant fibroblasts defective in peroxisomal alpha-oxidation or mitochondrial beta-oxidation, or in normal fibroblasts treated with methyl palmoxirate to inhibit mitochondrial beta-oxidation. Therefore, the retroconversion step in docosahexaenoic acid formation occurs through peroxisomal beta-oxidation in normal human cells. These results demonstrate that the pathway for docosahexaenoic acid synthesis in human cells involves 24-carbon intermediates. The limited ability to synthesize docosahexaenoic acid may underlie some of the pathology that occurs in genetic diseases involving peroxisomal beta-oxidation.