Visual acuity and the essentiality of docosahexaenoic acid and arachidonic acid in the diet of term infants

Child health and the environment: the INMA Spanish Study

The INMA (INfancia y Medio Ambiente [Environment and Childhood]) is a population-based cohort study in different Spanish cities, that focuses on prenatal environmental exposures and growth, development and health from early fetal life until childhood. The study focuses on five primary areas of research: (1) growth and physical development; (2) behavioural and cognitive development; (3) asthma and allergies; (4) sexual and reproductive development; and (5) environmental exposure pathways. The general aims of the project are: (1) to describe the degree of individual prenatal exposure to environmental pollutants, and the internal dose of chemicals during pregnancy, at birth and during childhood in Spain; (2) to evaluate the impact of the exposure to different contaminants on fetal and infant growth, health and development; (3) to evaluate the role of diet on fetal and infant growth, health and development; and (4) to evaluate the interaction between persistent pollutants, nutrients and genetic determinants on fetal and infant growth, health and development. Extensive assessments will be carried out on 3100 pregnant women and children. Data will be collected by physical examinations, questionnaires, interviews, ultrasound and biological samples. Pregnant women are being assessed at 12, 20 and 32 weeks of gestation to collect information about environmental exposures and fetal growth. The children will be followed until the age of 4 years.

Versatile roles of docosahexaenoic acid in the prenatal brain: from pro- and anti-oxidant features to regulation of gene expression

Docosahexaenoic acid (DHA) is the most ubiquitous polyunsaturated fatty acid (FA) in brain tissue. It is selectively esterified to amino phospholipids (PL) and therefore it is highly prevalent at the cytofacial site of the plasma membrane where it may specifically participate in intracellular events. A highly selective DHA accumulation prior to birth is the result of maternal supply via the placenta through a bio-magnification process. Supplements of DHA via the intra-amniotic route to the fetal rat increase brain DHA levels and also confer neuroprotection to fetuses subjected to global ischemic stress. The protective effect has been attributed to an enhanced free radical scavenging capacity of DHA. Dietary deprivation of linolenic acid (LNA) during the perinatal life on the other hand, resulted in losses of DHA from cerebral PLs [M. Schiefermeier, E. Yavin, n-3 deficient and DHA-enriched diets during critical periods of the developing prenatal rat brain, J. Lipid Res. 43 (2002) 124-131]. LNA deprivation also caused changes in a number of gene markers the identification of which was attained by a labor-intensive suppression subtractive hybridization protocol using mRNA from 2-week-old postnatal brains [E. Yakubov, P. Dinerman, F. Kuperstein, S. Saban, E. Yavin, Improved representation of gene markers on microarray by PCR-select subtracted cDNA targets, Mol. Brain Res. 137 (2005) 110-118]. Most notable was a remarkable elevation of dopamine (DA) receptor (D1 and D2) genes as evaluated by quantitative RT-PCR, SDS-PAGE gel electrophoresis and immunochemical staining [F. Kuperstein, E. Yakubov, P. Dinerman, S. Gil, R. Eylam, N. Salem Jr., E. Yavin, Overexpression of dopamine receptor genes and their products in the postnatal rat brain following maternal n-3 FA dietary deficiency, J. Neurochem. 95 (2005) 1550-1562]. Over-expression of DA receptors has been attributed to a compensatory mechanism resulting from impairment in DA neurotransmitter production, storage and processing. In conclusion, DHA is a versatile molecule with a wide range of actions spanning from participation in cellular oxidative processes and intracellular signaling to modulatory roles in gene expression and growth regulation.

Compartmental analyses of plasma 13C- and 2H-labeled n-6 fatty acids arising from oral administrations of 13C-U-18:2n-6 and 2H5-20:3n-6 in newborn infants

Efficacy of (13)C-U-18:2n-6 and (2)H(5)-20:3n-6 toward synthesis of labeled-20:4n-6 was studied in newborn infants utilizing compartmental models of plasma labeled n-6 fatty acids (FA). Ten infants received oral doses of (13)C-U-18:2n-6 and (2)H(5)-20:3n-6 ethyl esters (100 and 2 mg/kg, respectively). Rate constant coefficients and half-lives (t((1/2))) of n-6 FA were determined from the time-course concentrations of labeled-FA. Plasma n-6 FA values approximated steady state concentrations. Synthetic and utilization rates were calculated. Eight percent (range, 2-21%) of plasma (13)C-U-18:2n-6 was used for synthesis of (13)C-18:3n-6, -20:2n-6, and -20:3n-6. Seventy percent of (13)C-20:3n-6 (mean, CV: 0.26) was available for synthesis of (13)C-20:4n-6. The percentage of (2)H(5)-20:3n-6 converted to (2)H(5)-20:4n-6 was lower (mean: 26%, p < 0.02) than the (13)C-labeled analogue. Turnover of 18:2n-6 in subjects and of 20:4n-6 in plasma was 4.2 g/kg/d (CV: 0.58) and 4.3 mg/kg/d (CV: 0.81), respectively. Intake of 18:2n-6 and 20:4n-6 were estimated to be 3.0 g/kg/d (+/-1.7) and 2.8 mg/kg/d (+/- 2.2), respectively. Infants required additional 18:2n-6 and 20:4n-6 (mean: 1.2 g and 1.5 mg/kg/d) above predicted intake amounts to maintain plasma concentrations of 18:2n-6 and 20:4n-6, in order to spare FA from fat stores.

A newly discovered member of the fatty acid desaturase gene family: a non-coding, antisense RNA gene to delta5-desaturase

The rate limiting steps in the conversion of 18-carbon unsaturated fatty acids to 20- and 22-carbon products are catalyzed by two desaturase enzymes (Delta5-desaturase and Delta6-desaturase) found within a lipid desaturase gene cluster. Careful examination of this cluster revealed the existence of a conventionally spliced (human) and an intronless (mouse and rat) non-coding RNA gene, reverse Delta5-desaturase, which is transcribed from the opposite strand of the Delta5-desaturase gene. The 654 bp human reverse Delta5-desaturase transcript contains 269 nucleotides that are complementary to exon 1 and intron 1 of the Delta5-desaturase transcript, and the 3'-end of this sequence contains a 143 nucleotide stretch that is 100% complementary to the 5'-end of the Delta5-desaturase. The rat and mouse transcripts are 1355 and 690 bp long and complementary to a portion of the first intron and the entire first exon of their respective Delta5-desaturases. All reverse Delta5-desaturase transcripts contain several stop codons in all frames suggesting that they do not encode a peptide. Reverse Delta5-desaturase RNA was detected in all rat tissues where Delta5-desaturase is expressed, and the transition between fasting and refeeding produced a significant increase in reverse Delta5-desaturase RNA relative to Delta5-desaturase mRNA. Transient expression of reverse Delta5-desaturase in CHO cells stably transformed with Delta5-desaturase produced a modest decrease in Delta5-desaturase mRNA (30%), but lowered Delta5-desaturase enzymatic activity by >70%. More importantly, a diet enriched in fish oil produced a reciprocal increase in reverse Delta5-desaturase mRNA and decrease in Delta5-desaturase mRNA that was accompanied by a 5-6-fold decrease in Delta5-desaturase enzyme activity. These findings support a significant role for reverse Delta5-desaturase as a natural antisense regulator of Delta5-desaturase.

Polyunsaturated fatty acid supplementation stimulates differentiation of oligodendroglia cells

Dietary polyunsaturated fatty acids (PUFAs) have been postulated as alternative supportive treatment for multiple sclerosis, since they may promote myelin repair. We set out to study the effect of supplementation with n-3 and n-6 PUFAs on OLN-93 oligodendroglia and rat primary oligodendrocyte differentiation in vitro. It appeared that OLN-93 cells actively incorporate and metabolise the supplemented PUFAs in their cell membrane. The effect of PUFAs on OLN-93 differentiation was further assessed by morphological and Western blot evaluation of markers of oligodendroglia differentiation: 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP), zonula occludens-1 (ZO-1) and myelin-associated glycoprotein (MAG). Supplementation of the OLN-93 cells with n-3 and n-6 PUFAs increased the degree of differentiation determined by morphological analysis. Moreover, CNP protein expression was significantly increased by gamma-linolenic acid (GLA, 18:3n-6) supplementation. In accordance with the OLN-93 results, studies with rat primary oligodendrocytes, a more advanced model of cell differentiation, showed GLA supplementation to promote oligodendrocyte differentiation. Following GLA supplementation, increased numbers of proteolipid protein (PLP)-positive oligodendrocytes and increased myelin sheet formation was observed during differentiation of primary oligodendrocytes. Moreover, increased CNP, and enhanced PLP and myelin basic protein expression were found after GLA administration. These studies provide support for the dietary supplementation of specific PUFAs to support oligodendrocyte differentiation and function.

Time for an oil check: the role of essential omega-3 fatty acids in maternal and pediatric health

Deficiency of omega-3 fatty acids (omega3FAs) is an often unrecognized determinant of clinical disease; the adequate availability of these essential nutrients may prevent affliction or facilitate health restoration in some pregnant women and developing offspring. The human organism requires specific nutrients in order to carry out the molecular processes within cells and tissues and it is well established that omega3FAs are essential lipids necessary for various physiological functions. Accordingly, to achieve optimal health for patients, care givers should be familiar with clinical aspects of nutritional science, including the assessment of nutritional status and judicious use of nutrient supplementation. In view of the mounting evidence implicating omega3FA deficiency as a determinant of various maternal and pediatric afflictions, physicians should consider recommending purified fish oil supplementation during pregnancy and lactation. Furthermore, omega3FA supplementation may be indicated in selected pediatric situations to promote optimal health among children.

N-3 fatty acids and cognitive and visual acuity development: methodologic and conceptual considerations

Several randomized clinical studies in infants born preterm and at term have explored the effects on visual acuity development of postnatal supplementation with various sources of docosahexaenoic acid (DHA). Higher visual acuity after DHA supplementation is a consistent finding in infants born preterm. For infants born at term, the results are less consistent and are better explained by differences in sensitivity of the visual acuity test (electrophysiologic tests being more sensitive than subjective tests) or by differences in the amount of DHA included in the experimental formula. Differences in the sensitivity of the test may also be relevant in discussions of whether the effects of DHA on visual acuity are transient or persistent. A smaller number of studies have attempted to study the effects of DHA on cognitive development. The major focus of this article is to review the types of methods that have been used to evaluate the effects of DHA on cognition and to provide the rationale for measures that are a better conceptual fit. Research is needed (1) to probe the effects of variable DHA exposure on infant and child development, (2) to measure outcomes that better relate to preschool and school-age cognitive function, and (3) to reinforce, and in some cases demonstrate, links between specific infant and preschool measures of cognitive development. We strongly encourage collaborations with developmental cognitive neuroscientists to facilitate these research goals.

Cell survival matters: docosahexaenoic acid signaling, neuroprotection and photoreceptors

Recent data have provided important clues about the molecular mechanisms underlying certain retinal degenerative diseases, including retinitis pigmentosa and age-related macular degeneration. Photoreceptor cell degeneration is a feature common to these diseases, and the death of these cells in many instances seems to involve the closely associated retinal pigment epithelial (RPE) cells. Under normal circumstances, both cell types are subject to potentially damaging stimuli (e.g. sunlight and high oxygen tension). However, the mechanism or mechanisms by which homeostasis is maintained in this part of the eye, which is crucial for sight, are an unsolved riddle. The omega-3 fatty acid family member docosahexaenoic acid (DHA), which is enriched in these cells, is the precursor of neuroprotectin D1 (NPD1). NPD1 inhibits oxidative-stress-mediated proinflammatory gene induction and apoptosis, and consequently promotes RPE cell survival. This enhanced understanding of the molecular basis of endogenous anti-inflammatory and neuroprotective signaling in the RPE presents an opportunity for the development of therapies for retinal degenerative diseases.

New Method Based on 1-(Trimethysilyl)alk-1-yne To Prepare 1,4-Skipped Diynes

[reaction: see text] We have developed a novel reaction between a terminal TMS-alkyne and a propargyl halide in the presence of a fluoride source and a catalytic amount of copper iodide to prepare 1,4-skipped diynes with good yields and in mild conditions. We have shown that this reaction also works very well with germanium and tin derivatives as an alternative to silicon. This new method can be useful for the synthesis of polyunsaturated fatty acids.

Formula supplemented with docosahexaenoic acid (DHA) and arachidonic acid (ARA): a critical review of the research

PURPOSE

To summarize results of randomized controlled trials (RCTs) evaluating growth, cognitive, neurological, and visual development of term infants supplemented with docosahexaenoic acid (DHA) and arachidonic acid (ARA).

DESIGN AND METHODS

The Boyack and Lookinland Methodological Quality Index (MQI) was used to evaluate data from RCTs identified from multiple data bases.

RESULTS

Six of ten studies found the addition of DHA and ARA to have no significant effect on infant development.

PRACTICE IMPLICATIONS

More expensive formula with endogenous DHA and ARA is not necessary. Results from longer studies currently underway will be beneficial.

Docosahexaenoic acid in red blood cells of term infants receiving two levels of long-chain polyunsaturated fatty acids

OBJECTIVES

A randomized, double-blind, prospective trial assessed effects of different formula levels of polyunsaturated fatty acids on blood phospholipid docosahexaenoic (DHA; 22:6omega3) and arachidonic acids (ARA; 20:4omega6) in term infants at 120 days of age.

METHODS

Healthy, formula-fed term infants (n = 78) were randomized to 1) routine milk-based formula with 8 mg DHA, 21 mg ARA, 110 mg alpha-linolenic (ALA; 18:3omega3), and 1,000 mg linoleic acids (LA; 18:2omega6) per 100 kcal (Lower-long-chain polyunsaturated fatty acids [LCPUFA]; n = 39) or 2) routine milk-based formula with 17 mg DHA, 34 mg ARA, 85 mg ALA, and 860 mg LA per 100 kcal (Higher-LCPUFA; n = 39). Fatty acid methyl esters from red blood cell (RBC) and plasma phospholipid fractions were assessed using capillary column gas chromatography.

RESULTS

Compared with infants fed Lower-LCPUFA formula, the Higher-LCPUFA group had significantly greater percentages of fatty acids as DHA in RBC phosphatidylethanolamine (PE), RBC phosphatidylcholine (PC), total RBC, and plasma phospholipids (P < 0.001). Infants fed Lower-LCPUFA formula had higher percentages of precursor omega6 fatty acids in the desaturation/elongation pathway but lower percentages of ARA (RBC PE, RBC PC, and plasma phospholipid, P < 0.001; total RBC, P = 0.017) compared with the Higher-LCPUFA group.

CONCLUSIONS

Greater amounts of dietary ALA do not produce as great an increase in DHA in blood lipids as preformed dietary DHA. Infants fed DHA at levels similar to human milk had significantly greater percentage of DHAat 120 days of age compared with the Lower-LCPUFA group despite higher precursor levels of ALA.

Synthesis of long-chain polyunsaturated fatty acids in lactating mammary gland: role of Δ5 and Δ6 desaturases, SREBP-1, PPARα, and PGC-1

The purpose of this work was to study whether rat lactating mammary gland can synthesize PUFAs through the expression of Delta5 and Delta6 desaturases (Delta5D and Delta6D), whether these enzymes are regulated by the transcription factors sterol-regulatory element binding protein 1 (SREBP-1) and peroxisome proliferator-activated receptor alpha (PPARalpha) and the coactivator peroxisome proliferator-activated receptor gamma coactivator 1beta (PGC-1beta), and whether these desaturases are regulated by the lipid concentration in the diet. The results showed that on day 12 of lactation, approximately 35% of the linoleic acid in the diet, which is the precursor of PUFAs, is transferred to the mammary gland. There was expression of Delta5D and Delta6D in mammary gland, and it was regulated by the corn oil content in the diet. The higher the corn oil content in the diet, the lower the expression of both desaturases. Induction of Delta5D and Delta6D was associated positively with similar changes in SREBP-1 and PGC-1beta. Expression of PPARalpha was barely detected and was not affected by the corn oil content in the diet, whereas PGC-1beta expression increased as the corn oil in the diet increased. These results indicate that the lactating mammary gland has the capacity to synthesize PUFAs and can be regulated by the lipid content in the diet.

A randomized trial of long-chain polyunsaturated fatty acid supplementation in infants with phenylketonuria

Forty-two infants (20 males, 22 females) with classical phenylketonuria (PKU) entered a prospective, double-blind, randomized study to investigate the effects on biochemical and physiological outcomes of a phenylalanine-free infant formula containing a fat blend supplemented with the long-chain polyunsaturated fatty acids (LC-PUFA), docosahexaenoic acid (DHA, C22:6 n-3), and arachidonic acid (AA, C20:4 n-6). Between entry and 20 weeks (entry and 1y) of age, median DHA levels in erythrocyte membrane phospholipids decreased by 15% (22%) in the LC-PUFA supplemented group (n=21) and by 61% (64%) in the control group (p<0.001; n=18). A dietary supply of LC-PUFA in infants with PKU prevents the decline in DHA levels associated with a diet supplying minimal sources of LC-PUFA. DHA status in turn, independent of diet, may influence the maturation of the visual system in infants with PKU.

Overexpression of dopamine receptor genes and their products in the postnatal rat brain following maternal n-3 fatty acid dietary deficiency

A combination of PCR-Select cDNA subtraction and gene array hybridization was used to identify differentially expressed genomic markers in brains of rats fed for 3 weeks in utero and 2 weeks after birth on an n-3 polyunsaturated fatty acid (PUFA)-deficient diet supplied to dams. Total RNA was isolated, switch mechanism at 5'-end of the RNA transcripts (SMART) applied and used for PCR-Select subtraction of PUFA-deficient and adequately-fed control preparations. Subtracted and amplified ds-cDNA end-products were fragmented, terminally labeled with biotin-ddUTP and hybridized with a RN-U34A gene array. A 10-fold increase in potential genes with log2(Tester/Driver) = 1.4 was found compared with traditional gene array technology when the same chip was tested using non-subtracted targets. Reverse transcription-real-time relative PCR confirmed 30% of the transcripts. Among the validated transcripts, D1 and D2 receptors for dopamine (DA), were most prominent among a number of over-expressed neurotransmitter receptors and retinoic acid receptor (RXR alpha-2 and alpha-1). Immunohistochemical staining of brain sections from 2-week-old pups revealed a substantial enrichment of the D2 receptor in discrete regions of the mesolimbic and mesocortical pathways as well as in a large number of brain areas from the n-3 PUFA-deficient pups. Punches of the same areas run on western blots showed similar results. The overwhelming expression of D1 and D2 receptors may be attributed to a behavioral hypersensitivity caused by the possible impairment of DA production during brain development, which may have implications in certain disorders of the nervous system.

Can prenatal N-3 fatty acid deficiency be completely reversed after birth? Effects on retinal and brain biochemistry and visual function in rhesus monkeys

Our previous studies of rhesus monkeys showed that combined prenatal and postnatal n-3 fatty acid deficiency resulted in reduced visual acuity, abnormal retinal function, and low retina and brain docosahexaenoic acid content. We now report effects of n-3 fatty acid deficiency during intrauterine development only. Rhesus infants, born to mothers fed an n-3 fatty acid deficient diet throughout pregnancy, were repleted with a diet high in alpha-linolenic acid from birth to 3 y. Fatty acid composition was determined for plasma and erythrocytes at several time points, for prefrontal cerebral cortex biopsies at 15, 30, 45, and 60 wk, and for cerebral cortex and retina at 3 y. Visual acuity was determined behaviorally at 4, 8, and 12 postnatal weeks, and the electroretinogram was recorded at 3-4 mo. Total n-3 fatty acids were reduced by 70-90% in plasma, erythrocytes, and tissues at birth but recovered to control values within 4 wk in plasma, 8 wk in erythrocytes, and 15 wk in cerebral cortex. At 3 y, fatty acid composition was normal in brain phospholipids, but in the retina DHA recovery was incomplete (84% of controls). Visual acuity thresholds did not differ from those of control infants from mothers fed a high linolenic acid diet. However, the repleted group had lower amplitudes of cone and rod ERG a-waves. These data suggest that restriction of n-3 fatty acid intake during the prenatal period may have long-term effects on retinal fatty acid composition and function.

Long-chain polyunsaturated fatty acids in breast milk in La Plata, Argentina: relationship with maternal nutritional status

Milk fat is the major source of energy for breastfed infants; it also supplies polyunsaturated fatty acids (PUFAs) essential for the development of brain, retina, and other organs. Maternal nutritional status is critical for the newborn, and little information exists regarding the PUFA status of vulnerable populations living in Southern regions. We studied the relationship between maternal nourishment and milk fatty acid composition. Mother nutritional status (normal, overweight or obese) was estimated on the body mass index. Milk protein, total lipid, and fatty acid composition were determined. Milk protein was not affected by mother's nutritional status. In obese mothers an increase in lipid content, linoleic acid, total n-6 and total PUFAs was observed comparing to the other groups. Disregarding the nutritional status, the ratio n-6/n-3 fatty acids was very high and the 22:6n-3 content was very low, when compared with those of mothers from other countries. This finding led us to urge Public Health officers to promote changes in the dietary habits of nursing women.

Dietary PUFA for preterm and term infants: review of clinical studies

Human milk contains n-3 and n-6 LCPUFA (long chain polyunsaturated fatty acids), which are absent from many infant formulas. During neonatal life, there is a rapid accretion of AA (arachidonic acid) and DHA (docosahexaenoic acid) in infant brain, DHA in retina and of AA in the whole body. The DHA status of breast-fed infants is higher than that of formula-fed infants when formulas do not contain LCPUFA. Studies report that visual acuity of breast-fed infants is better than that of formula-fed infants, but other studies do not find a difference. Cognitive development of breast-fed infants is generally better, but many sociocultural confounding factors may also contribute to these differences. The effect of dietary LCPUFA on FA status, immune function, visual, cognitive, and motor functions has been evaluated in preterm and term infants. Plasma and RBC FA status of infants fed formulas supplemented with both n-3 and n-6 LCPUFA was closer to the status of breast-fed infants than to that of infants fed formulas containing no LCPUFA. Adding n-3 LCPUFA to preterm-infant formulas led to initial beneficial effects on visual acuity. Few data are available on cognitive function, but it seems that in preterm infants, feeding n-3 LCPUFA improved visual attention and cognitive development compared with infants receiving no LCPUFA. Term infants need an exogenous supply of AA and DHA to achieve similar accretion of fatty acid in plasma and RBC (red blood cell) in comparison to breast-fed infants. Fewer than half of all studies have found beneficial effects of LCPUFA on visual, mental, or psychomotor functions. Improved developmental scores at 18 mo of age have been reported for infants fed both AA and DHA. Growth, body weight, and anthropometrics of preterm and term infants fed formulas providing both n-3 and n-6 LCPUFA fatty acids is similar in most studies to that of infants fed formulas containing no LCPUFA. A larger double-blind multicenter randomized study has recently demonstrated improved growth and developmental scores in a long-term feeding study of preterm infants. Collectively, the body of literature suggests that LCPUFA is important to the growth and development of infants. Thus, for preterm infants we recommend LCPUFA intakes in the range provided by feeding of human milk typical of mothers in Western countries. This range can be achieved by a combination of AA and DHA, providing an AA to DHA ratio of approximately 1.5 and a DHA content of as much as 0.4%. Preterm infants may benefit from slightly higher levels of these fatty acids than term infants. In long-term studies, feeding more than 0.2% DHA and 0.3% AA improved the status of these fatty acids for many weeks after DHA; AA was no longer present in the formula, enabling a DHA and AA status more similar to that of infants fed human milk. The addition of LCPUFA in infant formulas for term infants, with appropriate regard for quantitative and qualitative qualities, is safe and will enable the formula-fed infant to achieve the same blood LCPUFA status as that of the breast-fed infant.

Regulated expression of endothelial lipase by porcine brain capillary endothelial cells constituting the blood-brain barrier

Normal neurological function depends on a constant supply of polyunsaturated fatty acids to the brain. A considerable proportion of essential fatty acids originates from lipoprotein-associated lipids that undergo uptake and/or catabolism at the blood-brain barrier (BBB). This study aimed at identifying expression and regulation of endothelial lipase (EL) in brain capillary endothelial cells (BCEC), major constituents of the BBB. Our results revealed that BCEC are capable of EL synthesis and secretion. Overexpression of EL resulted in enhanced hydrolysis of extracellular high-density lipoprotein (HDL)-associated sn-2-labeled [(14)C]20 : 4 phosphatidylcholine. [(14)C]20 : 4 was recovered in cellular lipids, indicating re-uptake and intracellular re-esterification. To investigate local regulation of EL in the cerebrovasculature, BCEC were cultured in the presence of peroxisome-proliferator activated receptor (PPAR)- and liver X receptor (LXR)-agonists, known to regulate HDL levels. These experiments revealed that 24(S)OH-cholesterol (a LXR agonist), bezafibrate (a PPARalpha agonist), or pioglitazone (a PPARgamma agonist) resulted in down-regulation of EL mRNA and protein levels. Our findings implicate that EL could generate fatty acids at the BBB for transport to deeper regions of the brain as building blocks for membrane phospholipids. In addition PPAR and LXR agonists appear to contribute to HDL homeostasis at the BBB by regulating EL expression.

Tissue accretion and milk content of docosahexaenoic acid in female rats after supplementation with different docosahexaenoic acid sources

BACKGROUND

Docosahexaenoic acid (DHA) is highly concentrated in the mammalian nervous and visual system. The fatty acid, which is required by the fetus and the newborn, is supplied by the mother from their tissue reservoirs. It has been suggested that mother's supplementation with DHA during pregnancy and even before pregnancy. Different sources of DHA are available for supplementation such as: single-cell algae triglycerides (TG), egg's yolk phospholipids (PL), DHA ethyl esther (EE), and sn-2 DHA monoacylglyceride (MG). We evaluated comparatively the effectiveness of these different DHA sources to produce tissue DHA accretion and to increase milk DHA content.

METHODS

Female Wistar rats fed a diet which provided no DHA, were daily supplemented by 40 days before mating (BM) and during the pregnancy with either TG, PL, EE, or MG to an amount which provided 8 mg/kg b.w. of DHA. Samples of blood plasma, erythrocytes, hepatic and adipose tissue were obtained from rats at the BM condition and after the delivery (AD), and milk samples were also obtained from the gastric content of the pups nursed by the rats at day 3, 11 and 20 of suckling. Samples were processed to assess DHA and arachidonic acid (AA) content by gas-chromatography.

RESULTS

TG, PL, EE, and MG supplementation produced a similar intestinal absorption of DHA as estimated from the plasma DHA at the BM condition. However, PL and MG supplementation produced a higher accretion of DHA into erythrocytes, hepatic, and adipose tissue than TG and EE supplementation at the BM condition. AA content was not modified by the different supplementing oils. A reduction of the DHA content of plasma, erythrocytes, hepatic and adipose tissue at the AD condition was observed, and a reduction of AA for the hepatic and adipose tissues was also observed, suggesting the importance of these tissues as DHA and AA reservoirs. Milk secretion from PL and MG supplemented rats showed a higher DHA content than secretion from TG- and EE-supplemented rats.

CONCLUSIONS

We conclude that PL and MG supplementation provides higher tissue DHA accretion and higher milk DHA content than TG and EE supplementation. However, we were not able to visualize the comparative advantages derived from PL vs. MG supplementation.

Is docosahexaenoic acid, an n-3 long-chain polyunsaturated fatty acid, required for development of normal brain function? An overview of evidence from cognitive and behavioral tests in humans and animals

This review is part of a series intended for nonspecialists that will summarize evidence relevant to the question of whether causal relations exist between micronutrient deficiencies and brain function. Here, we focus on experiments that used cognitive or behavioral tests as outcome measures in experimental designs that were known to or were likely to result in altered brain concentrations of the n-3 fatty acid docosahexaenoic acid (DHA) during the perinatal period of "brain growth spurt." Experimental designs reviewed include observational breastfeeding studies and randomized controlled trials in humans and studies in rodents and nonhuman primates. This review is based on a large number of expert reviews and commentaries and on some 50 recent studies in humans and animals that have not yet been included in published reviews. Expert opinion regarding the strengths and weaknesses of the major experimental systems and uncertainties associated with interpreting results is summarized. On the basis of our reading of this literature, we conclude that evidence from several types of studies, particularly studies in animals, suggests that, within the context of specific experimental designs, changes in brain concentrations of DHA are positively associated with changes in cognitive or behavioral performance. Additional experimental information required to conclude that a causal association exists is discussed, as are uncertainties associated with applying results from specific experimental designs to the question of whether infant formula should be supplemented with DHA.

Methods of visual acuity determination with the spatial frequency sweep visual evoked potential

PURPOSE

The spatial frequency sweep visual evoked potential (sVEP) is used to rapidly determine visual acuity in children or non-responsive patients. Two techniques have been used to separate signal from noise: (1) the 95% confidence interval for the signal amplitude (95% CI) or (2) the amplitude of a Fourier frequency adjacent to 2x the signal frequency (DFT). The purpose of this study is to determine if there is a significant difference in acuity estimates with these techniques.

METHODS

Ten normal subjects (approximately 0.00 logMAR acuity) and 11 patients with decreased visual acuity took part in this project. Stimulus production and data analysis were done with an Enfant 4010 (Neuroscientific Corp). Standard VEP recording techniques were employed. The stimulus was a horizontal-oriented, sine wave grating that swept up the spatial frequency spectrum (contrast 80%, temporal reversal rate 7.5 Hz). Sweeps were repeated until the confidence intervals for the data were no longer decreasing. The Bailey Lovie logMAR chart was used to determine visual acuity. A line was fit to the high spatial frequency data using either the 95% CI or the DFT as the noise estimate. By using these linear equations, acuity estimates were obtained at 0, 1, and 2 microV signal amplitudes.

RESULTS

The average logMAR acuity for the subjects with normal acuity was -0.06 +/- 0.070 (SD). The sVEP acuity estimates were 0.08 +/- 0.098, 0.18 +/- 0.092, and 0.33 +/- 0.195 (0, 1, and 2 microV extrapolations) with the 95% CI used as noise and 0.07 +/- 0.100, 0.18 +/- 0.103, and 0.33 +/- 0.202 (0, 1, and 2 microV extrapolations) with the DFT used as noise. By using the average noise from the Fourier frequency as the extrapolation level, the acuity was 0.10 +/- 0.098 logMAR. The average logMAR acuity for the subjects with decreased visual acuity was 0.67 +/- 0.306 (SD). The sVEP acuity estimates were 0.53 +/- 0.175, 0.66 +/- 0.171, and 0.88 +/- 0.295 (0, 1, and 2 microV extrapolations) with the 95% CI used as noise and 0.53 +/- 0.179, 0.65 +/- 0.176, and 0.86 +/- 0.268 (0, 1, and 2 microV extrapolations) with the DFT used as noise. By using the average noise from the Fourier frequency as the extrapolation level, the acuity was 0.57 +/- 0.186 logMAR. No significant difference was found between the two acuity estimate techniques for all of the subjects (repeated measures ANOVA, p = 0.16, F20 = 2.131). The sVEP estimates of acuity to the 0 microV and noise levels were not significantly different from the logMAR acuity (paired t-test, all p values > 0.05).

CONCLUSIONS

The results indicate that the sVEP acuity does not depend on the noise estimation technique. In agreement with prior studies, the sVEP acuity underestimates the logMAR acuity in normally sighted individuals by about an octave.

Incomplete replacement of docosahexaenoic acid by n-6 docosapentaenoic acid in the rat retina after an n-3 fatty acid deficient diet

When sources of n-3 fatty acids are not present in the diet, nervous system docosahexaenoic acid (22:6n3) is replaced by docosapentaenoic acid (22:5n6). Dams were fed either an n-3 deficient diet or one containing alpha-linolenic acid (18:3n3) and 22:6n3 throughout pregnancy and lactation. Their male offspring at weaning also received either the n-3 deficient or n-3 adequate diets and were sacrificed at 5, 10, 20, 50 and 91 days of age. Retinal lipids were extracted and analysed by gas chromatography for fatty acyl content. The percentage of retinal 22:6n3 increased continuously over the 13 week course of the experiment but reached its maximal concentration around day 20. Non-reciprocal replacement of 22:6n3 by 22:5n6 was observed at postnatal day 20 and 50 but not at other time points. Complete replacement of 22:6n3 was apparent if elevations in both 22:5n6 and docosatetraenoic acid (22:4n6) were considered. These data indicate that during the rapid period of accretion of retinal 22:6n3 around postnatal day 20, the supply of 22:5n6 to the retina was inadequate to completely replace 22:6n3 in n-3 deficient rats.

Supplementation of infant formula with long-chain polyunsaturated fatty acids does not influence the growth of term infants

BACKGROUND

Adequate growth is an important indicator of health and well-being in infants.

OBJECTIVE

Our objective was to determine the effect of supplementing infant formula with long-chain polyunsaturated fatty acids (LCPUFAs) on the growth of term infants.

DESIGN

Using the methodology outlined by the Cochrane Collaboration, we reviewed all known randomized controlled trials that involved LCPUFA supplementation of infant formula fed to term infants. Outcome measures were weight, length, and head circumference. Original data obtained from the investigators of published trials were used. Outcomes were analyzed with fixed-effects or random-effects model meta-analyses and were reported as weighted mean differences with 95% CIs.

RESULTS

We identified 14 eligible trials that had data available for meta-analysis (1846 infants). Trial quality was generally high. Meta-analysis showed no significant effect of LCPUFA supplementation on infant weight, length, or head circumference at any assessment age. Similarly, subgroup analyses showed that supplementation with only n-3 LCPUFAs (no arachidonic acid) had no significant effect on infant weight, length, or head circumference. The source of LCPUFA supplementation (phospholipid or triacylglycerol) also did not significantly affect infant growth.

CONCLUSION

We found no evidence that LCPUFA supplementation of infant formula influences the growth of term infants in either a positive or a negative way.

Visual maturation of term infants fed long-chain polyunsaturated fatty acid-supplemented or control formula for 12 mo

BACKGROUND

Several studies found a benefit of long-chain polyunsaturated fatty acid (LCP) supplementation for visual or mental development, but others found no benefit. Likely contributors to differences among studies are the amount of LCP supplementation, functional outcomes, and sample size.

OBJECTIVE

We evaluated LCP supplementation in amounts typical for human milk (based on local and worldwide surveys) in a large cohort of infants by using sweep visual evoked potential (VEP) acuity as the functional outcome.

DESIGN

The study was a double-masked, randomized, controlled clinical trial in 103 term infants. By age 5 d, infants were randomly assigned to receive either formula with no docosahexaenoic acid (DHA) or arachidonic acid (ARA) or formula supplemented with DHA and ARA as 0.36% and 0.72%, respectively, of total fatty acids. Sweep VEP acuity was the primary outcome. Random dot stereoacuity, blood lipid profile, growth, and tolerance were secondary outcomes.

RESULTS

VEP acuity in the LCP-supplemented group was significantly better than that in the control group at ages 6, 17, 26, and 52 wk. Stereoacuity in the LCP-supplemented group was significantly better than that in the control group at age 17 wk but not at ages 39 and 52 wk. By ages 17 and 39 wk, the red blood cell DHA concentration in the LCP-supplemented group was more than double and more than triple, respectively, that in the control group. Growth of infants fed LCP-supplemented and control formulas did not differ significantly, and both diets were well tolerated.

CONCLUSION

LCP supplementation of term infant formula during the first year of life yields clear differences in visual function and in total red blood cell lipid composition.

Effect of placental function on fatty acid requirements during pregnancy

The fetus has an absolute requirement for the n-3/n-6 fatty acids and docosahexaenoic acid (22:6 n-3; DHA) in particular is essential for the development of the brain and retina. Most of the fat deposition in the fetus occurs in the last 10 weeks of pregnancy. The likely rate of DHA utilisation during late pregnancy cannot be met from dietary sources alone in a significant proportion of mothers. De novo synthesis makes up some of the shortfall but the available evidence suggests that the maternal adipose tissue makes a significant contribution to placental transport to the fetus. The placenta plays a crucial role in mobilising the maternal adipose tissue and actively concentrating and channelling the important n-3/n-6 fatty acids to the fetus via multiple mechanisms including selective uptake by the syncytiotrophoblast, intracellular metabolic channelling, and selective export to the fetal circulation. These mechanisms protect the fetus against low long-chain polyunsaturated fatty acid (LCPUFA) intakes in the last trimester of pregnancy and have the effect of reducing the maternal dietary requirement for preformed DHA at this time. As a result of these adaptations, small changes in the composition of the habitual maternal diet before pregnancy are likely to be more effective in improving LCPUFA delivery to the fetus than large dietary changes in late pregnancy. There is little evidence that DHA intake/status in the second half of pregnancy affects visual and cognitive function in the offspring, but more studies are needed, particularly in children born to vegetarian and vegan and mothers who may have very low intakes of DHA.

Comparison of bloodstream fatty acid composition from African-American women at gestation, delivery, and postpartum

Our aim was to examine the docosahexaenoic acid (DHA; 22:6n-3) status of pregnant African-American women reporting to the antenatal clinic at Wayne State University in a longitudinal study design. Fatty acid compositions of plasma and erythrocyte total lipid extracts were determined and food frequency surveys were administered at 24 weeks of gestation, delivery, and 3 months postpartum for participants (n = 157). DHA (mean +/- SD) in the estimated total circulating plasma was similar at gestation (384 +/- 162 mg) and delivery (372 +/- 155 mg) but was significantly lower at 3 months postpartum (178 +/- 81 mg). The relative weight percentage of DHA and docosapentaenoic acid n-6 (DPAn-6; 22:5n-6) decreased postpartum, whereas their respective metabolic precursors, eicosapentaenoic acid (EPA; 20:5n-3) and arachidonic acid (AA; 20:4n-6), increased. Similar results were found in erythrocytes. Dietary intake of DHA throughout the study was estimated at 68 +/- 75 mg/day. The relative amounts of circulating DHA and DPAn-6 were increased during pregnancy compared with 3 months postpartum, possibly via increased synthesis from EPA and AA. The low dietary intake and blood levels of DHA in this population compared with others may not support optimal fetal DHA accretion and subsequent neural development.

Effects of alcohol intake during pregnancy on docosahexaenoic acid and arachidonic acid in umbilical cord vessels of black women

OBJECTIVE

Alcohol influences the intake and metabolism of several nutrients including long-chain polyunsaturated fatty acids (LC-PUFAs). The LC-PUFAs docosahexaenoic acid (DHA) and arachidonic acid (AA) are particularly crucial for intrauterine growth and brain development. We hypothesized that alcohol consumption adversely affects LC-PUFA levels in pregnant women and their newborn infants.

METHODS

Pregnant black women (N = 208) presenting at a core city antenatal clinic were screened and recruited. Shortly before delivery, maternal plasma was collected. After delivery, umbilical arteries and veins were dissected from the cords, total lipids were extracted from the vessel tissues and maternal plasma, and fatty acid levels were assayed by gas chromatography. For statistical analysis, subjects were categorized according to absolute alcohol intake per day (AAD) and absolute alcohol intake per drinking day (AADD) around the time of conception, with smoking and other potential confounders included in the analyses.

RESULTS

Significant differences in fatty acid composition of total lipid extracts were detected in umbilical cord vessels among the AADD groups: abstainers (AADD = 0), moderate drinkers (AADD < 130 g), and heavy drinkers (AADD > or = 130 g). DHA and AA content in the arterial umbilical vessel wall was approximately 14% and approximately 10% higher in the moderate (n = 127) and heavy (n = 32) alcohol groups, respectively, than in abstainers (n = 49). A small, nonsignificant increase ( approximately 3%) was seen in the umbilical vein for AA but not for DHA. Alcohol intake was positively correlated to both DHA and AA concentrations in the arterial vessel wall but to neither in the venous wall nor maternal plasma. Maternal plasma DHA was positively correlated with both umbilical arteries and vein DHA, but there were no significant correlations for AA between maternal plasma and either umbilical vessel.

CONCLUSIONS

Our findings indicate that alcohol intake during pregnancy is associated with altered DHA and AA status in fetal tissues. Although differences may be due to either metabolism and/or distribution, it is most likely a result of a direct influence of alcohol on fetal metabolism.

Duration of long-chain polyunsaturated fatty acids availability in the diet and visual acuity

BACKGROUND

Little is known about the critical period during which the dietary supply of long-chain polyunsaturated fatty acids (LCPUFAs) may influence the maturation of visual cortical function in term infants.

AIM

To define the relationship between duration of dietary LCPUFA supply and visual acuity at 52 weeks of age.

STUDY DESIGN

Data from 243 infants who participated in four randomized clinical trials of LCPUFA supplementation of infant formula at a single research center were combined. The primary outcome was visual acuity at 52 weeks of age as measured by swept visual evoked potentials (sweep VEP).

RESULTS

Longer duration of LCPUFA supply was associated with better mean acuity at 52 weeks of age (r=-0.878; p<0.001). The relationship between duration of dietary LCPUFA supply and sweep VEP acuity at 52 weeks was similar whether the LCPUFAs were provided via formula containing 0.36% DHA and 0.72% ARA or human milk. Duration of breast-feeding was associated with individual infants' sweep VEP acuity outcomes at 52 weeks (r=-0.286; p<0.005). The duration of LCPUFA supply during infancy has a similar relationship to sweep VEP acuity at 52 weeks in breastfed infants regardless of birth order.

CONCLUSION

A continued benefit from a supply of LCPUFAs is apparent in infants through 52 weeks of age, suggesting that the brain may not have sufficient stores of LCPUFAs from an early postnatal supply to support the optimal maturation of the visual cortex.

Update on Nutrition for Preterm and Full-Term Infants

Child health and development are contingent on sound nutrition during the neonatal period. The nutritional needs of all infants include adequate intake of fluid and energy; a balance among proteins, carbohydrates, and fats; and proper vitamin and mineral intake. Preterm infants have similar nutritional requirements but demand more frequent assessment of nutritional health and ongoing adjustment of nutritional intake throughout the neonatal period to ensure appropriate growth and development. Evidence-based nursing practice calls for an update on the specific nutritional requirements of infants, special nutritional needs of preterm infants, and the most recent changes in the composition of infant formula.

Maternal DHA and the development of attention in infancy and toddlerhood

Infants were followed longitudinally to document the relationship between docosahexaenoic acid (DHA) levels and the development of attention. Erythrocyte (red-blood cell; RBC) phospholipid DHA (percentage of total fatty acids) was measured from infants and mothers at delivery. Infants were assessed in infant-control habituation at 4, 6, and 8 months augmented with psychophysiological measures, and on free-play attention and distractibility paradigms at 12 and 18 months. Infants whose mothers had high DHA at birth showed an accelerated decline in looking over the 1st year and increases in examining during single-object exploration and less distractibility in the 2nd year. These findings are consistent with evidence suggesting a link between DHA and cognitive development in infancy.

Environmental light and heredity are associated with adaptive changes in retinal DHA levels that affect retinal function

Retinas of rats and mice react to environmental and genetic stimuli by altering the level of DHA in their rod outer segment membranes. We propose that this adaptation is a neuroprotective response to control the number of photons captured by rhodopsin and the efficiency of visual transduction, under conditions where excessive activation of the transduction cascade could lead to cell death.

Maturation of visual acuity is accelerated in breast-fed term infants fed baby food containing DHA-enriched egg yolk

Between 6 and 12 mo of age, blood levels of the (n-3) long-chain PUFA, docosahexaenoic acid (DHA), in breast-fed infants typically decrease due to diminished maternal DHA stores and the introduction of DHA-poor solid foods displacing human milk as the primary source of nutrition. Thus, we utilized a randomized, clinical trial format to evaluate the effect of supplemental DHA in solid foods on visual development of breast-fed infants with the primary outcome, sweep visual-evoked potential (VEP) acuity, as an index for maturation of the retina and visual cortex. At 6 mo of age, breast-fed infants were randomly assigned to receive 1 jar (113 g)/d of baby food containing egg yolk enriched with DHA (115 mg DHA/100 g food; n = 25) or control baby food (0 mg DHA; n = 26). Gravimetric measures were used to estimate the supplemental DHA intake which was 83 mg DHA/d in the supplemented group and 0 mg/d in controls. Although many infants in both groups continued to breast-feed for a mean of 9 mo, RBC DHA levels decreased significantly between 6 and 12 mo (from 3.8 to 3.0 g/100 g total fatty acids) in control infants, whereas RBC DHA levels increased by 34% from 4.1 to 5.5 g/100 g by 12 mo in supplemented infants. VEP acuity at 6 mo was 0.49 logMAR (minimum angle of resolution) and improved to 0.29 logMAR by 12 mo in controls. In DHA-supplemented infants, VEP acuity was 0.48 logMAR at 6 mo and matured to 0.14 logMAR at 12 mo (1.5 lines on the eye chart better than controls). At 12 mo, the difference corresponded to 1.5 lines on the eye chart. RBC DHA levels and VEP acuity at 12 mo were correlated (r = -0.50; P = 0.0002), supporting the need of an adequate dietary supply of DHA throughout 1 y of life for neural development.

Prenatal exposure to methylmercury and child development: influence of social factors

BACKGROUND

In the Seychelles Child Development Main Study (SCDS), at 19 months of age, enhanced MDI scores were associated with increasing methylmercury (MeHg) exposure in higher caregiver IQ groups at several levels of family income. We performed a similar analysis of the 66-month evaluations to determine if the modifying influences of social and environmental factors were consistent with those previously observed.

METHODS

Prenatal MeHg exposure was determined by analysis of maternal hair growing during pregnancy. Children in the cohort (N=711) were evaluated for cognitive ability (McCarthy Scales of Children's Abilities), language development (Preschool Language Scale), drawing and copying (Bender Gestalt Test), scholastic achievement (the Woodcock-Johnson Test of Achievement), and behavior (the Child Behavior Checklist). Interactions between prenatal MeHg exposure and caregiver intelligence, socioeconomic status (SES), home environment, and gender were examined by multiple regression analysis.

RESULTS

The median prenatal MeHg exposure was 5.9 ppm (range=0.5-26.7 ppm). Gender significantly influenced the association between prenatal exposure and drawing and copying; however, the effects were not consistent. Prenatal exposure interacted with one or more social or environmental covariates for general cognitive ability, overall language ability, and prearithmetic achievement. Again, the effects were not consistent across either endpoints or covariate categories.

CONCLUSIONS

Evidence of a small influence by social and environmental variables at 66 months is neither internally consistent nor consistent with earlier results. Overall, a consistent pattern of effect modification (EM) has not been observed, suggesting that the results may be due to chance.

The traditional diet of Greece and cancer

The term 'Mediterranean diet', implying that all Mediterranean people have the same diet, is a misnomer. The countries around the Mediterranean basin have different diets, religions and cultures. Their diets differ in the amount of total fat, olive oil, type of meat, wine, milk, cheese, fruits and vegetables; and the rates of coronary heart disease and cancer, with the lower death rates and longer life expectancy occurring in Greece. The diet of Crete represents the traditional diet of Greece prior to 1960. Analyses of the dietary pattern of the diet of Crete shows a number of protective substances, such as selenium, glutathione, a balanced ratio of n-6/n-3 essential fatty acids (EFA), high amounts of fibre, antioxidants (especially resveratrol from wine and polyphenols from olive oil), vitamins E and C, some of which have been shown to be associated with lower risk of cancer, including cancer of the breast. Epidemiological studies and animal experiments indicate that n-3 fatty acids exert protective effects against some common cancers, especially cancers of the breast, colon and prostate. Many mechanisms are involved, including suppression of neoplastic transformation, cell growth inhibition, and enhanced apoptosis and anti-angiogenicity, through the inhibition of eicosanoid production from n-6 fatty acids; and suppression of cyclooxygenase 2 (COX-2), interleukin 1 (IL-1) and IL-6 gene expression by n-3 fatty acids. Recent intervention studies in breast cancer patients indicate that n-3 fatty acids, and docosahexaenoic acid (DHA) in particular, increase the response to chemopreventive agents. In patients with colorectal cancer, eicosapentaenoic acid (EPA) and DHA decrease cell proliferation, and modulate favourably the balance between colonic cell proliferation and apoptosis. These findings should serve as a strong incentive for the initiation of intervention trials that will test the effect of specific dietary patterns in the prevention and management of patients with cancer.

Neuroprotectin D1: a docosahexaenoic acid-derived docosatriene protects human retinal pigment epithelial cells from oxidative stress

Docosahexaenoic acid (DHA) is a lipid peroxidation target in oxidative injury to retinal pigment epithelium (RPE) and retina. Photoreceptor and synaptic membranes share the highest content of DHA of all cell membranes. This fatty acid is required for RPE functional integrity; however, it is not known whether specific mediators generated from DHA contribute to its biological significance. We used human ARPE-19 cells and demonstrated the synthesis of 10,17S-docosatriene [neuroprotectin D1 (NPD1)]. This synthesis was enhanced by the calcium ionophore A-23187, by IL-1beta, or by supplying DHA. Under these conditions, there is a time-dependent release of endogenous free DHA followed by NPD1 formation, suggesting that phospholipase A(2) releases the mediator's precursor. Added NPD1 potently counteracted H(2)O(2)/tumor necrosis factor alpha oxidative-stress-triggered apoptotic RPE DNA damage. NPD1 also up-regulated the antiapoptotic proteins Bcl-2 and Bcl-x(L) and decreased proapoptotic Bax and Bad expression. Moreover, NPD1 (50 nM) inhibited oxidative-stress-induced caspase-3 activation. NPD1 also inhibited IL-1beta-stimulated expression of cyclooxygenase 2 promoter transfected into ARPE-19 cells. Overall, NPD1 protected RPE cells from oxidative-stress-induced apoptosis, and we predict that it will similarly protect neurons. This lipid mediator therefore may indirectly contribute to photoreceptor cell survival as well. Because both RPE and photoreceptor cells die in retinal degenerations, our findings contribute to the understanding of retinal cell survival signaling and potentially to the development of new therapeutic strategies.

Nutritional modulation of neonatal outcomes

In humans, growth and development continues until early adulthood when bone, muscle, and nervous tissue reaches final stages of maturity. Adequate levels of nutritional intake and utilization are critical to optimize ongoing growth. The goal of nutritional therapy for premature or ill neonates has been to provide sufficient nutrients to allow growth to continue at rates seen in utero. Functional immaturity of the gut in the premature infant makes absorption and utilization of nutritional substrates difficult. Premature infants are at risk for developing necrotizing enterocolitis, a potentially lethal bowel disorder. The etiology of necrotizing enterocolitis is not well understood, and a number of theories of causation have been proposed. Breast milk, the optimal source of nutrition for the neonate, is believed to confer some protection against necrotizing enterocolitis. A number of breast milk components have been credited with antiinflammatory properties. Breast milk is recognized for its benefits, yet for preterm infants breast milk alone does not promote adequate growth. A number of breast milk supplements have been investigated to facilitate growth and development and to prevent necrotizing enterocolitis. This article addresses development of the fetal gastrointestinal system, focusing on the biological mediators for normal function and the role of human breast milk and its additives in optimizing neonatal growth. The possible etiologies of necrotizing enterocolitis are discussed in terms of the relationship between this disease and enteral feeding practices.

Influence of the state of alertness on the pattern visual evoked potentials (PVEP) in very young infant

The aim of the study was to evaluate the pattern visual evoked potentials (PVEP) combined with an optimal state of vigilance, called liberated state (LS), in order to improve testing in very young infants. Transient PVEP were recorded in response to a checkerboard pattern of 120, 60 and 30 min of arc. in 56 fullterm newborns and 79 preterm infants from birth to 4 months of age. In the fullterms, 28 infants in each group were tested in LS or spontaneous alertness (SA) while in the preterms, 48 infants in each group were tested in LS or SA. No significant difference was found in the amplitude and/or peak time of the PVEP responses between subjects tested in LS compared to SA groups. However, the LS condition improved by approximately 25% the feasibility of prolonged PVEP testing in preterms aged less than 2 months (corrected age). This suggest that the LS condition enhances the clinical feasibility of PVEP testing in very young infants and should be used to optimize the evaluation of visual development in high risk infants in this age group.

Survey of breast-feeding practices and outcomes in the cystic fibrosis population

The aim of this study was to survey cystic fibrosis (CF) patients to determine the frequency of breast-feeding and its association with onset and severity of CF symptoms. Three thousand, two hundred questionnaires were sent to 30 accredited CF centers for anonymous completion. Eight hundred and sixty-three questionnaires were returned and scanned into a database. All results were adjusted for age at time of filling out the questionnaire. Age at onset of symptoms, percent forced expired volume in 1 sec (FEV1%) predicted, and intravenous (IV) antibiotic use were analyzed based on breast-feeding history. Approximately 49% of respondents received human breast milk at some time, but only 18% were exclusively breast-fed. Breast-feeding exclusively for greater than 6 months was associated with a decrease in disease severity based on recent intravenous antibiotic use compared to no breast-feeding (P = 0.03). There was no statistically significant change in onset of symptoms in the setting of breast-feeding; however, a trend toward delayed onset was seen in those receiving human milk. Fifty-three percent of those who breast-fed exclusively > or = 6 months had FEV1% values > 90%, compared to 47% of those not breast-fed. This is a suggestive but not statistically significant difference. In conclusion, breast-feeding for > or = 6 months is associated with decreased use of intravenous antibiotics in the 2 years prior to administering the questionnaire. This survey indicates that breast-feeding is not harmful to children with CF, and may be beneficial.

Test-retest reliability of swept visual evoked potential measurements of infant visual acuity and contrast sensitivity

The aim of the study was to describe variations in swept visual evoked potential (SWEEP-VEP) assessment of visual acuity and contrast sensitivity in infants and to evaluate the best way to estimate visual performance from obtained SWEEP-VEP data. The visual performance of 92 infants (6-40 wk of age) was measured in two separate visits. Results were verified with repeated tests in seven adults. There was a strong association between the two measurements of infant visual acuity (r = 0.91, p < 0.001), with no constant bias and an inter-assay coefficient of variation of 8.4%. The intra-assay coefficient of variation was 17% and in repeated sessions all obtained acuity measures were normally distributed, indicating that the mean and not the maximum threshold best estimates visual acuity. This estimate of visual acuity also had lower test-retest variability than those calculated from the maximum threshold or threshold from the average EEG signals (p = 0.001). Test-retest measures of infant contrast sensitivity had a correlation coefficient of 0.72 (p < 0.001) and an inter-assay coefficient of variation of 23%. With the observed test-retest variability, SWEEP-VEP is less valid for estimating the visual performance of individual subjects, but it can give reliable group means. This method was well suited to describe visual development in the infants, which for acuity as well as contrast sensitivity increased by 0.64 octave per doubling in age. However, the variability of the SWEEP-VEP method can be a limiting factor, for example, in the assessment of the potential effect of dietary docosahexaenoic acid in a homogeneous group of infants.

Alpha-linolenic acid supplementation during human pregnancy does not effect cognitive functioning

Increasing evidence suggests a positive association between docosahexaenoic acid (DHA, 22:6n-3) and cognitive performance. In addition, pregnancy is associated with a reduction of the DHA status and cognitive deficits. In the current study, cognition was assessed in pregnant women receiving a margarine enriched with alpha-linolenic acid (ALA, 18:3n-3, the ultimate dietary precursor of DHA) and some linoleic acid (LA, 18:2n-6, to prevent a possible reduction in n-6 fatty acids). A control group received a margarine enriched with LA only. ALA supplementation hardly affected the maternal DHA status and no significant differences were found in cognitive performance between the two groups. This indicates that ALA supplementation during pregnancy does not affect cognitive performance during and 32 weeks after gestation. At week 14 of pregnancy and 32 weeks after delivery, higher plasma DHA levels were associated with lower cognitive performance as indicated by longer reaction times on the finger precuing task (partial correlation coefficients 0.3705 and 0.4633, respectively, P<0.01). Since this could imply an unexpected adverse association between DHA and certain aspects of cognitive functioning this certainly needs further investigation.

Problems with essential fatty acids: time for a new paradigm?

The term 'essential fatty acid' is ambiguous and inappropriately inclusive or exclusive of many polyunsaturated fatty acids. When applied most rigidly to linoleate and alpha-linolenate, this term excludes the now well accepted but conditional dietary need for two long chain polyunsaturates (arachidonate and docosahexaenoate) during infancy. In addition, because of the concomitant absence of dietary alpha-linolenate, essential fatty acid deficiency is a seriously flawed model that has probably led to significantly overestimating linoleate requirements. Linoleate and alpha-linolenate are more rapidly beta-oxidized and less easily replaced in tissue lipids than the common 'non-essential' fatty acids (palmitate, stearate, oleate). Carbon from linoleate and alpha-linolenate is recycled into palmitate and cholesterol in amounts frequently exceeding that used to make long chain polyunsaturates. These observations represent several problems with the concept of 'essential fatty acid', a term that connotes a more protected and important fatty acid than those which can be made endogenously. The metabolism of essential and non-essential fatty acids is clearly much more interconnected than previously understood. Replacing the term 'essential fatty acid' by existing but less biased terminology, i.e. polyunsaturates, omega3 or omega6 polyunsaturates, or naming the individual fatty acid(s) in question, would improve clarity and would potentially promote broader exploration of the functional and health attributes of polyunsaturated fatty acids.