Long-chain polyunsaturated fatty acids attenuate the IL-1ß-induced proinflammatory response in human fetal intestinal epithelial cells.

BACKGROUND: Evidence suggests that excessive inflammation of the immature intestine may predispose premature infants to necrotizing enterocolitis (NEC). We investigated the anti-inflammatory effects of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (ARA) in human fetal and adult intestinal epithelial cells (IEC) in primary culture. METHODS: Human fetal IEC in culture were derived from a healthy fetal small intestine (H4) or resected small intestine of a neonate with NEC (NEC-IEC). Intestinal cell lines Caco2 and NCM460 in culture were used as models for mature IEC. IEC in culture were pretreated with 100 µmol/l palmitic acid (PAL), DHA, EPA, ARA, or ARA+DHA for 48 h and then stimulated with proinflammatory IL-1ß. RESULTS: DHA significantly attenuated IL-1ß induced proinflammatory IL-8 and IL-6 protein and mRNA in fetal H4, NEC-IEC, and mature Caco2, NCM460 IEC, compared to control and PAL treatment. DHA downregulated IL-1R1 (IL-1ß receptor) and NFk ß1 mRNA expression in fetal and adult IEC. ARA had potent anti-inflammatory effects with lower IL-8 and IL-6 (protein and mRNA) in fetal H4 but not in NEC-IEC or adult IEC. CONCLUSION: The present study provides evidence that DHA and ARA may have important anti-inflammatory functions for prevention of NEC in premature infants.

Disturbance in uniformly 13C-labelled DHA metabolism in elderly human subjects carrying the apoE ε4 allele.

Carrying the apoE ε4 allele (E4+ ) is the most important genetic risk for Alzheimer's disease. Unlike non-carriers (E4- ), E4+ seem not to be protected against Alzheimer's disease when consuming fish. We hypothesised that this may be linked to a disturbance in n-3 DHA metabolism in E4+. The aim of the present study was to evaluate [13C]DHA metabolism over 28 d in E4+ v. E4-. A total of forty participants (twenty-six women and fourteen men) received a single oral dose of 40 mg [13C]DHA, and its metabolism was monitored in blood and breath over 28 d. Of the participants, six were E4+ and thirty-four were E4-. In E4+, mean plasma [13C]DHA was 31% lower than that in E4-, and cumulative b-oxidation of [13C]DHA was higher than that in E4- 1­28 d post-dose (P ≤0·05). A genotype x time interaction was detected for cumulative b-oxidation of [13C]DHA (P ≤ 0·01). The whole-body half-life of [13C]DHA was 77% lower in E4+ compared with E4- (P ≤0·01). In E4+ and E4-, the percentage dose of [13C]DHA recovered/h as 13CO2 correlated with [13C]DHA concentration in plasma, but the slope of linear regression was 117% steeper in E4+ compared with E4- (P ≤ 0·05). These results indicate that DHA metabolism is disturbed in E4+, and may help explain why there is no association between DHA levels in plasma and cognition in E4+. However, whether E4+ disturbs the metabolism of 13C-labelled fatty acids other than DHA cannot be deduced from the present study.

Odd- and branched-chain fatty acids in milk fat from Holstein dairy cows are influenced by physiological factors.

Dairy products are the major source of odd- and branched-chain fatty acids (OBCFAs), a group of nutrients with emerging health benefits. The animal diet is known to influence milk fat OBCFAs of dairy cows; however, little is known about the effects of physiological factors. The objective of this study was to investigate the effects of parity and lactation stage on OBCFAs in milk fat of dairy cows. Holstein dairy cows (n = 157) were selected according to parity (first, second, third, or greater) and days in milk (DIM) (≤21 DIM, 21 < DIM ≤ 100, 100 < DIM ≤ 200, >200 DIM). All cows were fed the same total mixed ration for three weeks. Milk samples were collected during the last three days of each lactation stage for fatty acid (FA) analyses via gas chromatography. Results showed that first- and second-parity cows displayed significantly higher proportions and yields of iso-14:0, iso-15:0, iso-16:0, total iso-FA, and total branched-chain FA (P < 0.05) compared with other parities. The proportions of C17:0 and C17:1 cis-9 were also greater in first-parity cows (P < 0.05), while the yields of C17:0 and C17:1 cis-9 were similar among different parities (P > 0.05). The proportions of total OBCFAs were greater in first- and second-parity cows (P < 0.05), whereas the highest yield was observed in second-parity cows. Lactation dairy cows in ≤ 21 DIM group displayed lower proportions of iso-13:0, anteiso-13:0, C13:0, iso-14:0, C15:0, iso-16:0, total iso-FA, and total OBCFAs compared with that of the other groups (P < 0.05), and also lower yields of iso-14:0 and iso-16:0 (P < 0.05). In contrast, C17:0 and C17:1 cis-9 proportions and yields were higher in dairy cows with ≤ 21 DIM (P < 0.05). Iso-17:0 and anteiso-17:0 were not affected by lactation stage (P > 0.05). Taken together, our data showed that both parity and lactation stage have considerable effects on milk fat OBCFAs of dairy cows. In summary, first- and second-parity cows had higher milk OBCFAs compared with later parity cows, and OBCFAs with medium chain lengths were lower in dairy cows with ≤ 21 DIM, while C17:0 and C17:1 cis-9 were higher. These findings show that milk OBCFA contents are differentially modulated by physiological state. They will be useful in future studies that seek to alter OBCFA composition of Holstein dairy cow milk fats.

Neurodevelopment, nutrition and genetics. A contemporary retrospective on neurocognitive health on the occasion of the 100th anniversary of the National Institute of Nutrition, Hyderabad, India.

In celebration of the centenary of the National Institute of Nutrition (NIN), Hyderabad, India (1918-2018), a symposium highlighted the progress in nutrition knowledge made over the century, as well as major gaps in implementation of that knowledge. Brain famine caused by a shortage of nutrients required for perinatal brain development has unfortunately become a global reality, even as protein-calorie famine was largely averted by the development of high yield crops. While malnutrition remains widespread, the neglect of global food policies that support brain development and maintenance are most alarming. Brain disorders now top the list of the global burden of disease, even with obesity rising throughout the world. Neurocognitive health, remarkably, is seldom listed among the non-communicable diseases (NCDs) and is therefore seldom considered as a component of food policy. Most notably, the health of mothers before conception and through pregnancy as mediated by proper nutrition has been neglected by the current focus on early death in non-neurocognitive NCDs, thereby compromising intellectual development of the ensuing generations. Foods with balanced essential fatty acids and ample absorbable micronutrients are plentiful for populations with access to shore-based foods, but deficient only a few kilometres away from the sea. Sustained access to brain supportive foods is a priority for India and throughout the world to enable each child to develop to their intellectual potential, and support a prosperous, just, and peaceful world. Nutrition education and food policy should place the nutritional requirements for the brain on top of the list of priorities.

Survey of the erythrocyte EPA+DHA levels in the heart attack/stroke belt.

BACKGROUND: The Omega-3 Index (O3I; erythrocyte EPA+DHA as a percent of total fatty acids) is inversely related to risk for cardiovascular disease (CVD). The cardioprotective target O3I is 8%-12%. O3I levels in American regions with high CVD risk are poorly characterized. PURPOSE: To determine the O3I in individuals participating in a Seafood Nutrition Partnership (SNP) survey in seven US cities in the CVD "belt." METHODS: Fingerstick blood samples were analyzed for the O3I. RESULTS: The SNP cohort (n = 2177) had a mean (SD) O3I of 4.42% (1.12%). Only 1.2% were in the desirable range, whereas 42% had an undesirable (<4%) O3I. The mean (SD) O3I in a subset of 772 SNP subjects who were matched for age and sex with the Framingham study was 4.6% (1.2%) compared 5.3% (1.6%) in the Framingham cohort (p < 0.0001). CONCLUSIONS: Individuals in the CVD "belt" had relatively low O3I levels. Since in other settings, a low O3I is associated with increased risk for CVD, this may be one factor contributing to the higher risk for CVD in this region of the US.

A rare eicosanoid precursor analogue, sciadonic acid (5Z,11Z,14Z-20:3), detected in vivo in hormone positive breast cancer tissue.

Numerous genetic alterations of HSA 11q13 are found frequently in several cancer types, including breast cancer (BC). The 11q13 locus harbors FADS2 encoding Δ6 desaturation which is not functional in several cancer cell lines, including hormone positive MCF7 BC cells. In vitro, the non-functional FADS2 activity unmasks 18:2n-6 elongation to 20:2n-6 and Δ5 desaturation by FADS1 to yield 5Z,11Z,14Z-20:3 (sciadonic acid) rather than 5Z,8Z,11Z,14Z-20:4 (arachidonic acid). In this pilot study we aimed to determine whether 5,11,14-20:3 appears in vivo in hormone positive human BC tissue. Fatty acids were profiled in surgically removed human breast tumor and adjacent normal tissue (n = 9). Sciadonic acid was detected in three of nine breast tumor samples and was below detect limits in normal breast tissue. The internal Δ8 double bond of arachidonic acid is required for normal eicosanoid synthesis but is missing in sciadonic acid. This pilot study demonstrates for the first time in vivo sciadonic acid in hormone positive BC tissue, warranting a larger survey study to further evaluate its appearance and the functional implications.

The intramolecular delta(15)N of lysine responds to respiratory status in Paracoccus denitrificans.

Presented here is the first experimental evidence that natural, intramolecular, isotope ratios are sensitive to physiological status, based on observations of intramolecular delta(15)N of lysine in the mitochondrial mimic Paracoccus denitrificans. Paracoccus denitrificans, a versatile, gram-negative bacterium, was grown either aerobically or anaerobically on isotopically-characterized ammonium as sole cell-nitrogen source. Nitrogen isotope composition of the biomass with respect to source ammonium was Delta(15)N(cell - NH4) = delta(15) - delta(15)N(NH4) = -6.2 +/- 1.2 per thousand for whole cells under aerobic respiration, whereas cells grown anaerobically produced no net fractionation (Delta(15)N(cell - NH4) = -0.3 +/- 0.23 per thousand). Fractionation of (15)N between protein nitrogen and total cell nitrogen increased during anaerobic respiration and suggests that residual nitrogen-containing compounds in bacterial cell membranes are isotopically lighter under anaerobic respiration. In aerobic cells, the lysine intramolecular difference between peptide and sidechain nitrogen is negligible, but in anaerobic cells was a remarkable Delta(15)N(p - s) = delta(15)N(peptide) - delta(15)N(sidechain) = +11.0 per thousand, driven predominantly by enrichment at the peptide N. Consideration of known lysine pathways suggests this to be likely due to enhanced synthesis of peptidoglycans in the anaerobic state. These data indicate that distinct pathway branching ratios associated with microbial respiration can be detected by natural intramolecular Deltadelta(15)N measurements, and are the first in vivo observations of position-specific measurements of nitrogen isotope fractionation.

BCFA suppresses LPS induced IL-8 mRNA expression in human intestinal epithelial cells.

Branched chain fatty acids (BCFA) are components of common food fats and are major constituents of the normal term human newborn GI tract. Polyunsaturated fatty acids (PUFA) have been suggested to reduce the risk and development of inflammatory bowel diseases (IBD); however, little is known about the influence of BCFA on inflammation. We investigated the effect of BCFA on interleukin (IL)-8 and NF-κB production in a human intestinal epithelial cell line (Caco-2). Cells were pre-treated with specific BCFA, or DHA, or EPA, and then activated with lipopolysaccharide (LPS). Both anteiso- and iso- BCFA reduce IL-8. Anteiso-BCFA more effectively suppressed IL-8 than iso-BCFA in LPS stimulated Caco-2 cells. However BCFA in general were less effective than DHA or EPA. Activated BCFA-treated cells expressed less of the cell surface Toll-like receptor 4 (TLR-4) compared to controls. These are the first data to show the reduction of pro-inflammatory markers in human cells mediated by BCFA.

Acetyl CoA carboxylase shares control of fatty acid synthesis with fatty acid synthase in bovine mammary homogenate.

The objectives of this research were to determine the flux control coefficients for acetyl CoA carboxylase and fatty acid synthase using an in vitro preparation of bovine mammary homogenate. For an enzyme to be considered rate limiting with the use of metabolic control analysis, its control coefficient would be equal to unity. The hypothesis for this experiment was that the control coefficient for acetyl CoA carboxylase was not equal to unity, and that this enzyme was not, therefore, the rate-limiting step. Mammary tissue was isolated from lactating Holstein cows at slaughter and frozen in liquid nitrogen. Tissue was ground, homogenized, and centrifuged to obtain a postmitochondrial supernatant for use in in vitro incubations containing labeled acetate. Specific inhibitors for acetyl CoA carboxylase and fatty acid synthase were used to fractionally inhibit de novo synthesis for the calculation of flux control coefficients. The composition of fatty acids synthesized in the absence of enzyme inhibitors was similar to the composition of fatty acids in the presence of inhibitors. Calculations following avidin inhibition of acetyl CoA carboxylase determined the flux control coefficient was 0.63 +/- 0.15, which means that 63% of the control of fatty acid synthesis is exerted by acetyl CoA carboxylase. The remaining control (37%) was from fatty acid synthase, which indicates a significant degree of control over the flux of acetate in de novo synthesis resides with this enzyme. The rate-limiting status ascribed to acetyl CoA carboxylase was not supported, because the flux control coefficient was less than unity. Metabolic control analysis, through its use of pathway product measurements, allows for potential interactions in the pathway such as feedback inhibition contribution to the flux control coefficients, which would not otherwise be considered in studies measuring enzyme kinetics with purified enzymes.

Novel characterisation of minor α-linolenic acid isomers in linseed oil by gas chromatography and covalent adduct chemical ionisation tandem mass spectrometry.

Discrimination between polyunsaturated fatty acid isomers with three double bonds is a great challenge, due to structural similarities and similar polarities. In this study, we report the identification of four minor geometrical isomers of α-linolenic acid (ALA) present in linseed oil samples: (9E,12Z,15E)-, (9Z,12Z,15E)-, (9Z,12E,15Z)- and (9E,12Z,15Z)-octadeca-9,12,15-trienoic acids, chromatographically resolved by gas chromatography (GC) using a new and highly polar ionic phase column (SLB-IL111). Gas chromatography-electron ionisation mass spectrometry (GC-EIMS) determined that the four unknown compounds were C18:3 n-3 isomers. The positional 9-12-15 C18:3 configuration was achieved by covalent adduct chemical ionisation tandem mass spectrometry (CACI-MS/MS) while geometrical configuration was established with analytical standards based on relative retention. We hypothesised that these isomers are formed during linseed oil deodorisation and postulate preferred and unfavoured isomerisation pathways of ALA.

Milk fat synthesis is unaffected by abomasal infusion of the conjugated diene 18:3 isomers cis-6,trans-10, cis-12 and cis-6,trans-8,cis-12.

It has been previously established that trans-10,cis-12 CLA is a potent inhibitor of milk fat synthesis. Although the mechanism of this action is not completely understood, it has been speculated that eicosanoid-like metabolites of this isomer formed by the activity of tissue desaturases may be responsible for its activity. The objective of this study was to investigate the effects of an enrichment containing an 18:3 conjugated diene, produced in the metabolism of trans-10,cis-12 CLA, on milk fat synthesis. Three rumen-fistulated Holstein cows (210+/-8 d in milk) were randomly assigned in a 3 x 3 Latin square experiment. Treatments were (i) control, (ii) trans-10,cis-12 CLA supplement (2.1 g/d; positive control), (iii) enrichment providing two conjugated diene 18:3 isomers (2.6 g/d of cis-6,trans-10,cis-12 and 4.0 g/d of cis-6,trans-8,cis-12) and trans-10,cis-12 CLA (2.1 g/d). Treatments were abomasally infused for 5 d at 4-h intervals, and there was a 7-d interval between periods. Milk yield, dry matter intake, and milk protein yield were unaffected by treatments. In contrast, the trans-10,cis-12 CLA supplement reduced milk fat yield by 27%, whereas the supplement enriched with conjugated diene 18:3 isomers (treatment iii) had no effect on milk fat yield beyond that attributable to its trans-10,cis-12 CLA content. The transfer efficiency of trans-10,cis-12 CLA into milk fat was 25 and 24% for treatments ii and iii, respectively. At the same time, the abomasally infused conjugated diene 18:3 isomers were transferred to milk fat with an efficiency of 33 and 41% for cis-6,trans-10,cis-12 and cis-6,trans-8,cis-12 18:3, respectively. Overall, short-term abomasal infusion of the conjugated diene 18:3 isomers had no effect on milk fat synthesis, thereby offering no support for an involvement of metabolites of trans-10,cis-12 CLA in the regulation of milk fat synthesis.

The expression of cytosolic phospholipase A2 and prostaglandin endoperoxide synthase in ovine maternal uterine and fetal tissues during late gestation and labor.

Gene expression of cytosolic phospholipase A2 (cPLA2) and prostaglandin endoperoxide synthase (PGHS) 1 and 2 was studied in ovine maternal uterine and fetal tissues during glucocorticoid induced premature labor and spontaneous labor and compared with gestational age matched controls not in labor. Northern blot analysis demonstrated that the messenger RNA (mRNA) abundance of cPLA2 and PGHS-2, but not PGHS-1, increased significantly in the endometrium during both glucocorticoid induced premature labor and spontaneous labor. Protein levels of the two enzymes measured by Western blot analyses were also elevated in the endometrium during glucocorticoid induced premature labor. cPLA2 mRNA was detected in the myometrium, but no difference was observed between ewes in labor and their gestational age matched controls not in labor. While the level of PGHS-2 mRNA was below detection in the myometrium with the methods used, the enzyme protein for PGHS-2 in the myometrium was significantly increased in both glucocorticoid induced premature labor and spontaneous labor. Using immunocytochemical methods, PGHS-2 enzyme protein was identified in the endometrial gland epithelial cells and myometrial cells. PGHS-2 mRNA was also detected in the ovine fetal cotyledons in which no differences for PGHS-2 mRNA existed between tissues collected from ewes in labor and ewes not in labor. In contrast, there were no detectable signals for cPLA2 or PGHS-2 mRNA in either amnion or chorion. We conclude that the ovine endometrium and myometrium, but not fetal membranes, are important tissue sites of prostaglandin biosynthesis involved in the process of ovine parturition.

Desaturation and interconversion of dietary stearic and palmitic acids in human plasma and lipoproteins.

Dietary saturated fatty acids are implicated as a risk factor for atherosclerosis. The conversion of the major dietary saturated fatty acids stearic acid (18:0) and palmitic acid (16:0) to monounsaturated fatty acids in whole plasma and lipoprotein fractions is reported for seven healthy adult humans over 6 d using [U-13C]stearic acid (18:0*) and [U-13C]palmitic acid (16:0*) and high-precision mass spectrometry. A tracer dose (28-32 mg) of 18:0* or 16:0* was loaded into an emulsion and orally administered before breakfast. Serial blood samples were collected on day 1 and fasting blood was drawn daily until day 7. Overall conversion of 18:0 to 18:1 was approximately 14%, whereas that of 18:0 to 16:0 was approximately 2% in plasma up to 144 h. Conversion of 16:0 to 16:1 was < 2%, whereas conversion of 16:0 to 18:0 was approximately 6%. No other fatty acid metabolites were detected for 18:0* or 16:0*. The conversion products were observed mainly in chylomicrons and very-low-density lipoproteins, indicating that the intestine and liver have comparable roles in desaturating 18:0 and 16:0. Overall, these data indicate that dietary 18:0 desaturation is severalfold greater than 16:0 desaturation. The low level (14%) of 18:0 desaturation in omnivorous adults may have little influence on blood lipid profiles relevant to atherosclerosis risk.

Direct analysis of carbon isotope variability in albumins by liquid flow-injection isotope ratio mass spectrometry.

We demonstrate the high precision C isotopic analysis of a series of purified albumins by liquid chromatography-combustion isotope ratio mass spectrometry (IRMS) by using direct aqueous liquid injection. Albumins from 18 species and albumens from chicken and turkey egg were obtained from a commercial source and shown to be of > 98% purity by capillary zone electrophoresis and high-performance liquid chromatography. One microliter of an aqueous protein solution with a total of < 40-pmol protein (2. 5 µg), which contained about 150-nmol C, was injected directly into a flowing stream of high-performance liquid chromatography grade water. The solution passed through a pneumatic nebulizer, was sprayed onto a moving wire, passed through a drying oven, and was combusted in a furnace. After the water of combustion was removed, the resulting CO2 gas was directed to a high precision IRMS instrument operated in continuous flow mode. The average precision across the 20 samples analyzed was SD(δ (13)C)=0.45%., and the average accuracy was δ(13)C < 0.4%. compared to aliquots analyzed by conventional preparation by using combustion tubes and dual inlet analysis. The observed isotope ratio range was about -22.5%. < δ (13)CPDB < -16%. as expected for modern materials from a natural source. These results demonstrate rapid, high precision, and accurate C isotopic analysis of untreated macromolecules in an aqueous stream by liquid source IRMS.

Studies of structure and mechanism in acetonitrile chemical ionization tandem mass spectrometry of polyunsaturated fatty acid methyl esters.

Recently it has been shown that acetonitrile chemical ionization tandem mass spectrometry (CI-MS/MS) is a rapid, on-line means to determine double bond position in fatty acid methyl esters (FAME). The mechanism of this gas phase condensation reaction has been studied. Evidence of the (1-methyleneimino)-1-ethenylium ion (m/z 54), formed upon the reaction of acetonitrile with itself, adding across the double bond in a [2 + 2] cycloaddition reaction is observed. When this nascent complex undergoes collision-induced dissociation, two diagnostic ions emerge. One of these ions results from loss of the hydrocarbon end of the FAME, whereas the other ion results from loss of the methyl ester end, and when considered together, the diagnostic ions localize the positions of the double bonds in the FAME. Several labeling and MS/MS/MS experiments on the two diagnostic ions were performed to determine a plausible fragmentation mechanism of the stable (1-methyleneimino)-1-ethenylium-FAME complex. The first generation product ions, or diagnostic ions, appear to be formed though a charge-driven mechanism, whereas the second generation product ions are formed via charge-remote fragmentations. Plausible mechanisms for the formation and subsequent dissociation of the diagnostic ions are presented for the monounsaturated, diunsaturated, and polyunsaturated (3 or more double bonds) FAME.

Use of stable isotopes to study fatty acid and lipoprotein metabolism in man.

Tracer studies have long been an important tool for lipid metabolism research. Recent advances and availability of high performance mass spectrometers (MS) and improved stable isotopically labeled tracers contribute to an increase in stable isotope tracer studies in humans. We briefly review recent studies and discuss advances in high sensitivity methods and applications. GC/MS analysis. Tracer studies with gas chromatography/mass spectrometry (GC/MS) usually rely on D labeling, where labeling with more that three D atoms shifts the analyte mass above that of the natural abundance envelope, and the MS monitors selected masses representing the isotopimers of interest. Recent examples are the work of Emken and coworkers, who investigated the desaturation of 18:0 and 16:0, and 18:2n-6 and 18:3n-3 elongation/desaturation, in adults, with oral doses of about 3 g of d2,4,6 fatty acids. They showed modest levels of 18:0 and 16:0 desaturation over 2 days and an influence of dietary 18:2n-6 on elongation. In premature infants, Salem, Uauy and coworkers recently have used d5-18:2n-6 and d5-18:3n-3 doses of 50-100 mg/kg body weight to show that infants as small as 1980 g and 32 weeks gestation elongate and desaturate both precursors within 24 h. Most fatty acid metabolites including 20:4n-6, 20:5n-3, and 22:6n-3 were easily detected in serum. High precision isotope ratio MS (IRMS). In 1992, we introduced a high sensitivity fatty acid tracer method based on [U-13C] tracers and GC-combustion-IRMS (GCC-IRMS). The combustion interface facilitates carbon-by-carbon tracer detection; with U-13C tracers all GC peaks are detected with highest precision. Rhee et al have quantified the desaturation of 18:0 and 16:0 in lipoproteins of adults using 30 mg oral doses (0.5 mg/kg). In the first 12 h, conversion of 18:0 to 18:1 was 7% in chylomicrons and 17% in VLDL, showing that both intestine and liver desaturate 18:0. Plasma conversion of 18:0 over 144 h was 14%, while that for 16:0 was 2%, showing that combined intestine and liver desaturation is minor compared with normal fluctuations in dietary levels. Carnielli applied GCC-IRMS to 8:0 elongation in very-low-birth-weight infants. Significant conversion products of 8:0 were 14:0 (5%), 16:0 (8%) but not 10:0 or 12:0.

Distribution of arachidonic, eicosapentaenoic, docosahexaenoic and related fatty acids in ovine endometrial phospholipids in late gestation and labor.

The quantitative distribution of phospholipid (PL) fatty acids from ovine endometrial tissues taken at 105 (n = 3) and 131 and 147 (n = 5) days of gestation age (dGA) and in spontaneous labor (SL, n = 3) is reported. Phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylserine (PS), and lysophosphatidylcholine (LPC), were separated by thin layer chromatography (TLC) and analyzed for fatty acid composition by quantitative gas chromatography (GC). Saturates are found mainly in PS and PI and unsaturates predominantly in PC and PE. The major long-chain polyunsaturated fatty acids (LC-PUFA), arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), are found primarily in PC, PE, and PI. AA accumulates in PC, PI and PS (p < 0.05) from late gestation to term and significantly declines in PC and PS (p < 0.02) during labor, suggesting that ovine endometrium is a possible source of prostaglandin (PG) precursors. EPA decreases significantly from around 105 dGA to term and at labor in PC (p < 0.02) and in PI (p < 0.01), which may indicate the involvement of 3-series PGs in the regulation of uterine contraction. Unsaturation index (UI) and total PUFA increase from late gestation to term in PE (p < 0.05) and decrease during labor (p < 0.05). The ratios of n-6/n-3 PUFA increase in PI (p < 0.05) and in PC (p < 0.01) during labor mainly due to the decline of EPA in these PL.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary phospholipid saturation increases with glucocorticoid receptor mRNAs in late gestation but not due to labor in the fetal rhesus monkey.

We report here changes in abundance of pulmonary cytosolic phospholipase A2 (cPLA2) and glucocorticoid receptor (GR) mRNAs and phospholipid (PL) fatty acids (FA) with gestational age, in either spontaneous or androstenedione-induced premature labor for 15 fetal rhesus monkeys and 1 neonate. Pulmonary RNA and lipids were extracted from the lungs of the rhesus monkeys, gestational ages ranging from 140 days to term. Northern hybridization analysis was performed for both cPLA2 and GR mRNAs. The results demonstrated the transcript of the cPLA2 constantly expressed and that of GR increased gradually in the lungs during the gestational stages studied. Phosphatidylcholine (PC), phosphatidylglycerol (PG) and phosphatidylinositol (PI) were separated by thin layer chromatography and the fatty acid composition in these PL was quantified by gas chromatography (GC). Regression analysis demonstrated that the expression of GR, mRNAs increased significantly with gestational age (P < 0.01). Furthermore, the level of GR mRNA is significantly correlated with that of cPLA2, with Pearson correlation coefficient of 0.83 (P < 0.01). The PC palmitate percentage increased significantly with gestational age (P < 0.01), while the PC unsaturation index and total polyunsaturated FA decreased during late gestation (P < 0.01). Changes in PG FA with gestational age were similar to those in PC, while PI FA did not change with gestational age. There was no effect of either spontaneous or induced labor on mRNA levels of cPLA2 and GR or the FA composition of pulmonary PL studied. We conclude that the pulmonary PL FA compositions are under developmental control.

Carbon recycling into de novo lipogenesis is a major pathway in neonatal metabolism of linoleate and alpha-linolenate.

Recent reports indicate that recycling of the beta-oxidized carbon skeleton of linoleate and alpha-linolenate into newly synthesized cholesterol and fatty acids in the brain is quantitatively significant in both suckling rats and pre- and postnatally in rhesus monkeys. The recycling appears to occur via ketones which are not only readily produced from these 18 carbon polyunsaturates but are also the main lipogenic precursors for the developing mammalian brain. Since the neonatal rat brain appears not to acquire cholesterol or long chain saturated or monounsaturated fatty acids from the circulation, ketones and ketogenic precursors seem to be crucial for normal brain synthesis of these lipids. Cholesterol is plentiful in brain membranes and it has also been discovered to be the essential lipid adduct of the 'hedgehog' family of proteins, the appropriate expression of which determines normal embryonic tissue patterning and neurological development. Insufficient cholesterol or inappropriate expression of 'sonic hedgehog' has major adverse neurodevelopmental consequences typified in humans by Smith-Lemli-Optiz syndrome. Hence, we propose that the importance of alpha-linolenate and linoleate for normal neural development arises not only from being precursors to longer chain polyunsaturates incorporated into neuronal membranes but, perhaps equally importantly, by being ketogenic precursors needed for in situ brain lipid synthesis.

Maternal intravenous administration of long chain n-3 polyunsaturates to the pregnant ewe in late gestation results in specific inhibition of prostaglandin h synthase (PGHS) 2, but not PGHS1 and oxytocin receptor mRNA in myometrium during betamethasone-induced labor.

OBJECTIVES: Both the onset of labor and time to delivery during betamethasone-induced delivery are delayed by omega-3 polyunsaturated fatty acid (PUFA) administration to pregnant sheep. That fatty acid also inhibits the labor-related increase in maternal plasma estradiol and maternal and fetal prostaglandin E(2). To evaluate the mechanism of inhibition of prostaglandin production and delay of onset of labor and time of delivery in PUFA-treated sheep, we determined the effect of PUFA on myometrial prostaglandin H synthase (PGHS) 1 and 2 and oxytocin receptor mRNA levels in betamethasone-induced labor. METHODS: At 124 days' gestation, a 20% emulsion of either intralipid (IL, n = 6) or PUFA (n = 6) was infused continuously (3 mL/kg per day) intravenously (IV) to the ewe. At 125 days' gestation, betamethasone was administered IV (10 microg/h over 48 hours) to fetuses of both intralipid- and PUFA-treated ewes. Myometrium was collected at necropsy either during betamethasone-induced labor as evaluated by myometrial electromyography or within 5 days of the termination of betamethasone infusion, if delivery did not occur after fetal betamethasone infusion. Total myometrial RNA was analyzed by Northern blot for oxytocin receptor and PGHS1 and 2 mRNA normalized for 18s. RESULTS: Treatment with PUFA decreased myometrial PGHS2 mRNA but did not alter myometrial PGHS1 and oxytocin receptor mRNA after betamethasone administration. CONCLUSIONS: This finding provides a mechanism whereby PUFA delays betamethasone-induced delivery in sheep and suggests a potential role of PUFA as an effective tocolytic agent in human pregnancy.