Intrauterine growth restriction is associated with changes in polyunsaturated fatty acid fetal-maternal relationships

Elevated hydroxyacylcarnitines in a carrier of LCHAD deficiency during acute liver disease of pregnancy - a common feature of the pregnancy complication?

Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency is a mitochondrial fatty acid beta-oxidation defect characterized by accumulation of long-chain hydroxyacylcarnitine intermediates and female carriers of this disorder are in risk for pregnancy complications. We found elevated blood long-chain hydroxyacylcarnitine species in a carrier of LCHAD deficiency at 31weeks of pregnancy with a LCHAD deficient fetus during acute fatty liver of pregnancy-like liver involvement, but had been within the normal range at 25weeks of pregnancy. This finding supports the hypothesis of acylcarnitine accumulation in pathogenesis of AFLP in carriers of LCHAD and MTP deficiencies.

Enhanced circulating retinol and non-esterified fatty acids in pregnancies complicated with intrauterine growth restriction

IUGR (intrauterine growth restriction) increases the incidence of perinatal complications and, although several placental transport functions have been shown to be altered in pregnancies complicated by IUGR, the mechanism behind it is not well understood. The aim of the present study was to investigate factors in maternal and cord blood plasma from normal and IUGR-complicated pregnancies associated with the body weight of newborns. At the time of Caesarean section, 24 women with IUGR pregnancies were compared with a group of 30 normal controls with AGA (appropriate gestational age) fetuses who were studied at Caesarean section, which took place 5 weeks later than IUGR pregnancies, and also to a group of 25 non-delivered gestational age-matched control pregnant women (AGA-35wk). Maternal plasma retinol, gamma- and alpha-tocopherol, NEFAs (non-esterified fatty acids), and palmitic, palmitoleic, gamma-linolenic and arachidonic acids were higher in women with IUGR pregnancies than in AGA-35wk controls, whereas stearic and alpha-linolenic acids were lower. Smaller differences were found when comparing these variables for IUGR and AGA women. However, umbilical vein plasma gamma-tocopherol, cholesterol, triacylglycerols and NEFAs were higher in the IUGR group than in the AGA group, whereas arachidonic acid was lower. Maternal plasma retinol and NEFAs were the only variables negatively correlated with birthweight when multiple linear regressions were analysed. In conclusion, the increased levels of circulating retinol and NEFAs in maternal plasma are negatively associated with birth and placental weights, which may reflect an impaired placental transfer in IUGR pregnancies. As retinoids are involved in the control of gene transcription, it is proposed that a decrease in placental transfer of retinol could underlie the metabolic dysfunction of IUGR pregnancies.

Impact of maternal undernutrition on diabetes and cardiovascular disease risk in adult offspring

Epidemiological, clinical, and experimental observations have led to the hypothesis that the risk of developing chronic diseases in adulthood is influenced not only by genetic and adult lifestyle factors, but also by environmental factors during early life. Low birth weight, a marker of intrauterine stress, has been linked to predisposition to cardiovascular disease (CVD) and diabetes. The compelling animal evidence and significant human data to support this conclusion are reviewed. Specifically, the review discusses the role of maternal nutrition before and during pregnancy, placental insufficiencies and epigenetic changes in the increased predisposition to diabetes and CVD in adult life. The impact of low birth weight and catch-up growth as they pertain to risk of disease in adult life is also discussed. In addition, adult disease risk in the overnourished fetus is also mentioned. Reference is made to some of the mechanisms of the induction of diabetes and CVD phenotype. It is proposed that fetal nutrition, growth and development through efficient maternal nutrition before and during pregnancy could constitute the basis for nutritional strategies for the primary prevention of diabetes and CVD.

Free fatty acid profiles in preeclampsia

Preeclampsia has many characteristics similar to the metabolic syndrome. One of these is aberrant lipid metabolism. We studied free fatty acid (FFA) profiles at baseline and after oral glucose load in 21 preeclamptic and 11 normotensive pregnant women. Insulin sensitivity was measured by intravenous glucose tolerance test. We found that serum total FFA concentrations at baseline were 67% higher in preeclamptic than in normotensive pregnancies (P=0.0002). The difference between the two groups was largest in the concentrations of oleic (75%), linoleic (129%) and arachidonic (315%) acids. Oral intake of glucose suppressed total FFA in preeclamptic women by 40% (95% CI 32.1-46.1%, P<0.0001) but only 24% in control women (95% CI 0.01-42.0%, P=0.045). Insulin sensitivity, which in preeclamptic women was 37% lower (P=0.009), was unrelated to total or any individual FFA concentration. We concluded that preeclamptic women have higher circulating FFA concentrations, which despite insulin resistance are suppressed by oral glucose loading.

Long chain fatty acids and dietary fats in fetal nutrition

Long chain polyunsaturated fatty acids are essential nutrients for a healthy diet. The different kinds consumed by the mother during gestation and lactation may influence pregnancy, fetal and also neonatal outcome. The amount of fatty acids transferred from mother to fetus depends not only on maternal metabolism but also on placental function, i.e. by the uptake, metabolism and then transfer of fatty acids to the fetus. The third trimester of gestation is characterized by an increase of long chain polyunsaturated fatty acids in the fetal circulation, in particular docosahexaenoic acid, especially to support brain growth and visual development. These mechanisms may be altered in pathological conditions, such as intrauterine growth restriction and diabetes, when maternal and fetal plasma levels of long chain polyunsaturated fatty acids undergo significant changes. The aim of this review is to describe the maternal and placental factors involved in determining fetal fatty acid availability and metabolism, focusing on the specific role of long chain polyunsaturated fatty acids in normal and pathological pregnancies.

Enhanced lumbar spine bone mineral content in piglets fed arachidonic acid and docosahexaenoic acid is modulated by severity of growth restriction

The infant born small size for gestational age (SGA) has low bone mass. Since dietary arachidonic acid (AA) and DHA enhance bone mass in normal-birth-weight piglets the objective of the present study was to test for such benefits in the SGA piglet. In the present 15 d study, two levels of dietary AA and DHA (6:1 ratio of AA:DHA diets, 0·6:0·1 or 1·2:0·2 g/100 g dietary fat) v. a control diet were tested for effects on growth, fatty acid status, whole-body and regional bone mineral content (BMC) and metabolism in SGA piglets categorised as either very low birth weight (VLBW; ≤ 1·0 kg; n 12) or low birth weight (LBW; 1·1 to 1·2 kg; n 18). Differences in outcomes for each body weight category were detected using ANOVA with post hoc Bonferroni tests. Growth was not influenced by diet, yet the LBW piglets fed 0·6:0·1 AA and DHA as g/100 g fat had elevated BMC in the spine, whereas the VLBW piglets had higher BMC of the spine if fed the higher intake of AA and DHA. In both weight categories, the higher intake of AA and DHA lowered bone resorption relative to controls, whereas bone formation was unchanged. Tissue fatty acid concentrations reflected dietary AA and DHA, especially trabecular bone of VLBW piglets. Whether the enhanced lumbar spine BMC is due to enhanced Ca absorption and thus suppression of bone resorption remains to be established.

Maternal and fetal fatty acid profile in normal and intrauterine growth restriction pregnancies with and without preeclampsia

The aim of this study was to evaluate maternal and fetal lipid profile in intrauterine growth restriction (IUGR) pregnancies with and without preeclampsia (PE). Thirteen normal pregnancies studied during the third trimester (control M) and 29 at elective cesarean section (control CS) were compared with 18 pregnancies complicated by IUGR (IUGR only) and with seven pregnancies complicated by both IUGR and PE (IUGR-PE). Total plasma fatty acids, triglycerides, cholesterol, and nonesterified fatty acids (NEFA) were determined in maternal and fetal plasma. Nutritional intake was analyzed. IUGR only mothers had lower percentage of linoleic acid (LA) and higher arachidonic acid (AA) than controls, partly explained by higher AA dietary intake. Higher levels of NEFA were observed both in IUGR only and in IUGR-PE mothers whereas triglyceride levels were increased in IUGR-PE mothers only. In IUGR-PE fetuses, LA and AA were significantly decreased, whereas triglyceride and NEFA concentrations were significantly increased compared with normal fetuses. In conclusion, IUGR only is associated with altered fatty acids profile not completely accounted by dietary changes. We hypothesize that the differences observed in IUGR with PE for triglycerides and other lipids could be related to a difference in maternal phenotype.

Whole blood fatty acid composition differs in term versus mildly preterm infants: small versus matched appropriate for gestational age

To investigate the associations between whole blood fatty acid (FA) profile and restricted intrauterine growth, any small for gestational age (SGA) infant born in our maternity ward through 1 y was matched with two appropriate for gestational age (AGA), of the same GA +/- 0.5 wk, infants, further subdivided into term and preterm. Whole blood was collected at d 4 on a strip and FA % composition assessed by means of gas chromatography. The whole sample consisted of 28 SGA versus 56 AGA born at term and 20 SGA versus 40 AGA born preterm at around 35 wks. Parent FA of the n-6 and n-3 FA families were higher in preterm groups, whereas docosahexaenoic acid was higher in term AGA (median % values, 3.9 versus 3.7 in term SGA, 2.8 in preterm AGA, and 2.5 in preterm SGA, p < 0.001). Term AGA had markedly higher values for the docosahexaenoic acid/alpha-linolenic acid ratio (median value: 91, versus 18 in term SGA, 12 in preterm AGA, and 10 in preterm SGA, p < 0.001). Term SGA had significantly lower levels of total monounsaturated FA and higher levels of eicosapentaenoic acid. Therefore, the 4-d whole blood FA pattern is associated with both GA and birth weight.

Long-chain polyunsaturated fatty acid (LC-PUFA) transfer across the placenta

Fetal long-chain polyunsaturated fatty acid (LC-PUFA) supply during pregnancy is of major importance, particularly with respect to docosahexaenoic acid (DHA) that is an important component of the nervous system cell membranes. Growing evidence points to direct effects of DHA status on visual and cognitive outcomes in the offspring. Furthermore, DHA supply in pregnancy reduces the risk of preterm delivery. Because of limited fetal capacity to synthesize LC-PUFA, the fetus depends on LC-PUFA transfer across the placenta. Molecular mechanisms of placental LC-PUFA uptake and transport are not fully understood, but it has been clearly demonstrated that there is a preferential DHA transfer. Thus, the placenta is of pivotal importance for the selective channeling of DHA from maternal diet and body stores to the fetus. Several studies have associated various fatty acid transport and binding proteins (FATP) with the preferential DHA transfer, but also the importance of the different lipolytic enzymes has been shown. Although the exact mechanisms and the interaction of these factors remains elusive, recent studies have shed more light on the processes involved, and this review summarizes the current understanding of molecular mechanisms of LC-PUFA transport across the placenta and the impact on pregnancy outcome and fetal development.

Effects of being born small for gestational age on long-term intellectual performance

Size at birth has been associated repeatedly with increased risk of cardiovascular morbidity and mortality later in life. However, there is accumulating evidence to suggest an association between being born small for gestational age (SGA) and increased risk of lower intelligence, poor academic performance, low social competence and behavioural problems, compared with individuals born appropriate for gestational age. Crude neurological handicaps, such as cerebral palsy, are extremely rare in children born SGA at term. Such handicaps are more common in very premature children. However, there does appear to be an increase in the risk for non-severe neurological dysfunction in individuals born SGA. Intellectual performance is evaluated in young children in several different ways, including standardized tests such as Weschler's Intelligence Scale - Revised, and teachers and parents' reports. In adulthood, indirect variables such as education and occupation are used in addition to standardized tests. It may be possible to modify the effects of SGA on intellectual development by breast feeding the baby for more than 6 months. Nutrient-enriched formula does not have any advantages when it comes to intellectual development, and induces a risk of rapid weight gain and eventually overweight. Growth hormone treatment may also have some effect on intelligence quotient.

Nutrient transport across the intrauterine growth-restricted placenta

This chapter is a brief review of the current literature on nutrient transport across the intrauterine growth restricted placenta in human pregnancies in vivo. These studies, performed at the time of fetal blood sampling or elective cesarean section, show that the placenta plays a very important role in the pathophysiology of intrauterine growth restriction, clarifying the mechanisms of impaired nutrient placental transport. Further studies are needed though to open new perspectives in the clinical management and in the prevention of the disease.

Long-chain omega-3 fatty acid supply in pregnancy and lactation

PURPOSE OF REVIEW

Long-chain omega-3 fatty acids are essential for the developing fetus. Docosahexaenoic acid, the most important omega-3 fatty acid, is an important component of neural and retinal membranes, and rapidly accumulates in the brain during gestation and the postnatal period. Positive associations have been shown between maternal intake of fish, seafood and omega-3 fatty acids during pregnancy and/or lactation and visual and cognitive development.

RECENT FINDINGS

The review focuses on new findings by both observational and interventional studies on the influence of omega-3 fatty acids during pregnancy or lactation on gestation length and birth weight, preterm delivery, preeclampsia, maternal depression and infant visual function and neural development.

SUMMARY

Omega-3 fatty acids have been associated with reduced risk of cardiovascular and other diseases. Observational and interventional studies indicate a significant association with prolonging gestation and reducing the risk of preterm delivery both in low-risk and in high-risk pregnancies. Further benefits have been suggested for intrauterine growth restriction, preeclampsia and postpartum depression, but the evidence is inconclusive. Higher maternal docosahexaenoic acid intake both in pregnancy and lactation is associated with positive infant neurodevelopmental outcomes. Women of reproductive age should achieve an average dietary docosahexaenoic acid intake of at least 200 mg/day.

Dietary fat intakes for pregnant and lactating women

Dietary fat intake in pregnancy and lactation affects pregnancy outcomes and child growth, development and health. The European Commission charged the research project PERILIP, jointly with the Early Nutrition Programming Project, to develop recommendations on dietary fat intake in pregnancy and lactation. Literature reviews were performed and a consensus conference held with international experts in the field, including representatives of international scientific associations. The adopted conclusions include: dietary fat intake in pregnancy and lactation (energy%) should be as recommended for the general population; pregnant and lactating women should aim to achieve an average dietary intake of at least 200 mg DHA/d; intakes of up to 1 g/d DHA or 2.7 g/d n-3 long-chain PUFA have been used in randomized clinical trials without significant adverse effects; women of childbearing age should aim to consume one to two portions of sea fish per week, including oily fish; intake of the DHA precursor, alpha-linolenic acid, is far less effective with regard to DHA deposition in fetal brain than preformed DHA; intake of fish or other sources of long-chain n-3 fatty acids results in a slightly longer pregnancy duration; dietary inadequacies should be screened for during pregnancy and individual counselling be offered if needed.

The effects of maternal dietary docosahexaenoic acid intake on rat pup myelin and the auditory startle response

We investigated the effects of maternal docosahexanoic acid (DHA) supplementation on pups' auditory startle responses and the composition of brain myelin.

METHODS

Timed-pregnant rats were fed throughout pregnancy and lactation diets that contained 0, 0.3, 0.7 or 3% of total fatty acids as DHA. Milk was collected from culled pups' stomachs on postnatal day (PND) 3, latency of the auditory startle reflex was measured on PND 15, and pups were killed and brains collected on PND 24.

RESULTS

Higher levels of DHA in maternal diet were reflected in milk and in pups' myelin. The latency of the auditory startle response was significantly longer in offspring of dams fed higher levels of DHA. There was a positive correlation between the myelin content of DHA and the latency of the startle response (p = 0.044), and a negative correlation between the myelin content of DHA and the myelin content of cholesterol (p = 0.005).

CONCLUSION

High levels of maternal DHA intake alter the lipid composition of rat pup myelin, and are associated with longer latencies of the auditory startle response--a myelin-dependent electrophysiologic response.

Placental transfer of long-chain polyunsaturated fatty acids (LC-PUFA)

Considerable evidence exists for marked beneficial effects of omega-3 long-chain polyunsaturated fatty acids (LC-PUFA) during pregnancy. The omega-3 LC-PUFA docosahexaenoic acid (DHA) is incorporated in large amounts in fetal brain and other tissues during the second half of pregnancy, and several studies have provided evidence for a link between early DHA status of the mother and visual and cognitive development of her child after birth. Moreover, the supplementation of omega-3 LC-PUFA during pregnancy increases slightly infant size at birth, and significantly reduces early preterm birth before 34 weeks of gestation by 31%. In our studies using stable isotope methodology in vivo, we demonstrated active and preferential materno-fetal transfer of DHA across the human placenta and found the expression of human placental fatty acid binding and transport proteins. From the correlation of DHA values with placental fatty acid transport protein 4 (FATP 4), we conclude that this protein is of key importance in mediating DHA transport across the human placenta. Given the great importance of placental DHA transport for infant outcome, further studies are needed to fully appreciate the effects and optimal strategies of omega-3 fatty acid interventions in pregnancy, dose response relationships, and the potential differences between subgroups of subjects such as women with gestational diabetes or other gestational pathology. Such studies should contribute to optimize substrate intake during pregnancy and lactation that may improve pregnancy outcome as well as fetal growth and development.

Intrauterine growth restriction is associated with alterations in placental lipoprotein receptors and maternal lipoprotein composition

Among other factors, fetal growth requires maternal supply of cholesterol. Cellular cholesterol uptake is mainly mediated by the LDL receptor (LDL-R) and the scavenger receptor family. We hypothesized that expression levels of key receptors of these families were regulated differently in placentas from IUGR pregnancies with varying degrees of severity. Third-trimester placentas from IUGR pregnancies with (IUGR-S) and without (IUGR-M) fetal hemodynamic changes and from control (AGA) pregnancies were studied. LDL-R, LDL-R-related protein (LRP-1), and scavenger receptor class B type I (SR-BI) mRNA and protein levels were measured. Cholesterol concentration and composition of lipoproteins were analyzed enzymatically and by lipid electrophoresis, respectively, in maternal and umbilical cord blood. LDL-R mRNA levels in IUGR-M were similar to AGA but lower (P < 0.05) in IUGR-S. In contrast, LDL-R protein was twofold (IUGR-M) and 1.8-fold (IUGR-S) higher (P < 0.05) than in the AGA group. LRP-1 mRNA and protein levels were not altered in the IUGR cases. SR-BI mRNA was unchanged in IUGR, but protein levels were lower (P < 0.05) in IUGR-S than in the other groups. Maternal plasma concentrations of LDL cholesterol were higher (P < 0.05) in the AGA group (188.5 +/- 23.6 mg/dl) than in the IUGR-S group (154.2 +/- 26.1). Electrophoretic mobility of the LDL fraction in maternal plasma demonstrated significant changes in migration toward higher values (AGA 0.95 +/- 0.06, IUGR-M 1.12 +/- 0.11, P < 0.001; IUGR-S 1.28 +/- 0.20, P = 0.002). We conclude that LDL-R and SR-BI levels are altered in IUGR pregnancies. These differences were associated with changes in LDL, but not HDL, mobility and cholesterol concentration in maternal circulation.

Expression pattern of fatty acid transport protein-1 (FATP-1), FATP-4 and heart-fatty acid binding protein (H-FABP) genes in human term placenta

Placental tissue from five women undergoing elective caesarean did not present differences in fatty acids or mRNA expression of FATP-1, FATP-4 and H-FABP in different placental locations. mRNA expression of FATP-1 and FATP-4 was significantly higher than H-FABP. The expression of L-FABP was too low in placenta for accurate quantification.

Role of nutrition in the development of the fetal cardiovascular system

Emerging evidence demonstrates that heart disease may originate during fetal development. This review will focus on the role of maternal nutrition in the development of the fetal cardiovascular system. Emphasis will be placed upon the concept that nutritional inadequacies during gestation may be major programming stimuli that alter fetal cardiac, as well as vascular, physiology and predispose an individual to cardiovascular abnormalities in postnatal life. It is hypothesized that this research area will yield new information, resulting in improved fetal nutrition, growth and development through efficient maternal nutrition before and during pregnancy and will form the basis for nutritional strategies for the primary prevention of cardiovascular disease.

Human fetal growth and organ development: 50 years of discoveries

Knowledge about human fetal growth and organ development has greatly developed in the last 50 years. Anatomists and physiologists had already described some crucial aspects, for example, the circulation of blood during intrauterine life through the fetal heart, the liver as well as the placenta. However, only in the last century physiologic studies were performed in animal models. In the human fetus, the introduction of ultrasound and Doppler velocimetry has provided data about the growth and development of the fetus and of the circulation through the different fetal districts. Moreover, in the last 2 decades we have learned about fetal oxygenation and fetal nutrient supply caused by the availability of fetal blood samples obtained under relatively steady state conditions. These studies, together with studies using stable isotope methodologies, have clarified some aspects of the supply of the major nutrients for the fetus such as glucose, amino acids, and fatty acids. At the same time, the relevance of placental function has been recognized as a major determinant of fetal diseases leading to intrauterine growth restriction. More recently, the availability of new tools such as 3-dimensional ultrasound and magnetic resonance imaging, have made possible the evaluation of the growth and development of fetal organs. This knowledge in the healthy fetus will improve the ability of clinicians to recognize abnormal phenotypes of the different fetal organs, thus allowing to stage fetal diseases.

Placental LPL gene expression is increased in severe intrauterine growth-restricted pregnancies

Intrauterine growth restriction (IUGR) is associated with reduced placental supply of nutrients to the fetus. Lipoprotein lipase (LPL) mediates the hydrolysis of triglycerides from maternal lipoproteins to obtain fatty acids. Here, we tested the hypothesis that placental LPL gene expression level is altered in pregnancies complicated by IUGR. To this purpose, 28 IUGR fetuses were identified during pregnancy and divided in two groups: 7 M-IUGR ["mild" IUGR, with normal umbilical artery pulsatility index (PI)] and 21 S-IUGR ("severe" IUGR, with abnormal PI). Moreover, 10 out of 28 IUGR pregnancies were associated with preeclampsia. Controls were 19 normal pregnancies delivering appropriate for gestational age (AGA) fetuses. Relative real-time quantification of LPL was carried out in RNA from placental chorionic villi by the DeltaDeltaCt method, using beta-actin as normalizing gene. Placental LPL mRNA expression levels were significantly higher in IUGR than in AGA. In particular, significantly higher values were observed in S-IUGR, independent from the concomitant association with preeclampsia. No significant relationship was observed between placental LPL mRNA expression levels or gestational age. In conclusion, placental LPL mRNA gene expression is increased in severe IUGR, characterized by enhanced vascular placental resistances and alterations of placental nutrient transport.

Maternal and cord blood long-chain polyunsaturated fatty acids are predictive of bone mass at birth in healthy term-born infants

Long-chain polyunsaturated fatty acids (LC PUFA) are associated with bone mass in animals and human adults, yet no data exist for human infants. Thus, the objective of this study was to establish that LC PUFA status is associated with bone mass in healthy infants. Thirty mother-infant pairs were studied for LC PUFA status by measuring maternal and cord blood red blood cells (RBC) for arachidonic acid (AA), eicosapentaenoic acid (EPA), and DHA. Infant anthropometry and lumbar spine 1-4, femur and whole-body bone mineral content (BMC) were measured within 15 d of delivery. Maternal and infant LC PUFA were tested for their relationship to BMC using Pearson correlation and backward step-wise regression analyses. At birth, the average gestational age was 39.3+/-1.1 wk and body weight was 3433+/-430 g. Cord RBC AA was positively correlated with whole-body BMC, AA:EPA positively correlated with lumbar spine 1-4 BMC and femur BMC. Maternal RBC AA was positively correlated with whole-body BMC. After accounting for infant weight using regression, whole-body BMC was positively predicted by cord RBC AA but none of the maternal LC PUFA; lumbar spine 1-4 BMC was positively predicted by cord RBCAA:EPA ratio but negatively by maternal DHA; and femur BMC was not predicted by cord LC PUFA but was negatively predicted by maternal DHA. Imbalances among the n-6 and n-3 LC PUFA by term gestation are associated with lower bone mass, suggesting that the maternal diet should be balanced in n-6 and n-3 LC PUFA.

Reduced docosahexaenoic acid synthesis may contribute to growth restriction in infants born to mothers who smoke

In newborn infants, progressive decrease in anthropometric values and impairment of the docosahexaenoic acid (DHA) status was associated with maternal smoking during pregnancy, with a parallel increase of the metabolic precursor of DHA, alpha-linolenic acid. Maternal smoking may impair DHA synthesis which may contribute to reduced fetal growth.

Placental phenotypes of intrauterine growth

The placenta is essential to nutrition before birth. Recent work has shown that a range of clearly defined alterations can be found in the placentas of infants with intrauterine growth restriction (IUGR). In the mouse, a placental specific knockout of a single imprinted gene, encoding IGF-2, results in one pattern of alterations in placenta structure and function which leads to IUGR. We speculate that the alterations in the human placenta can also be grouped into patterns, or phenotypes, that are associated with specific patterns of fetal growth. Identifying the placental phenotypes of different fetal growth patterns will improve the ability of clinicians to recognize high-risk patients, of laboratory scientists to disentangle the complexities of IUGR, and of public health teams to target interventions aimed at ameliorating the long-term adverse effects of inadequate intrauterine growth.

LC-PUFA content in human milk: is it always optimal?

The content of long-chain polyunsaturated fatty acids (LC-PUFAs) in human milk has been connected with infant growth and developmental indices. The LC-PUFA content of human milk usually reflects the dietary habits of mothers, so questions have been raised regarding the possibility of enriching maternal diet with LC-PUFAs during lactation (or even before) in order to improve infant outcome. Nevertheless, environmental and genetic factors have independent roles in affecting both maternal milk composition and infant development.

CONCLUSION

Diet-related differences in the LC-PUFA composition of human milk are under active investigation for their possible contribution to infant development, but environment- and gene-related differences in both human milk composition and maternal diet should be considered in evaluating the adaptive mechanisms of infants and the effects of specific LC-PUFA dietary supplementations.

Infants with intrauterine growth restriction have impaired formation of docosahexaenoic acid in early neonatal life: a stable isotope study

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

Small-for-gestational-age infants need dietary quality more than quantity for their development: the role of human milk

Infants born small for gestational age (SGA) show some forms of developmental delay throughout paediatric age, and up to adolescence. The positive effect of breastfeeding on development, observed in most studies on healthy, term infants, seems to be further stressed in the group of SGA infants, particularly if breastfeeding is protracted. Besides the close maternal-infant contact of breastfeeding, the nutritional factors of human milk, above all long-chain polyunsaturated fatty acids, including docosahexaenoic acid, may at least partly account for the observed association.

CONCLUSION

SGA infants represent a high-risk group, not only for developmental delay, but also for long-term, unfavourable metabolic consequences. Breastfeeding and human milk quality together could help to prevent some of the neurological and metabolic sequelae of being born growth retarded.

Pathophysiology of metabolic syndrome X and its links to the perinatal period

It is proposed that metabolic syndrome X is initiated in the perinatal period as a low-grade systemic inflammatory condition. Increased consumption of energy-dense diets by pregnant women and lactating mothers suppresses the activities of Delta-6 and Delta-5 desaturases not only in maternal tissues but also in fetal liver and the placenta, resulting in decreased plasma and tissue concentrations of long-chain polyunsaturated fatty acids omega-6 arachidonic acid (AA), omega-3 eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). EPA, DHA, and AA have negative feedback control on tumor necrosis factor-alpha and IL-6 synthesis. Hence, EPA, DHA, and AA deficiencies induced by an energy-dense diet increase generation of tumor necrosis factor-alpha and interleukin-6, markers of inflammation that in turn decrease production of endothelial nitric oxide and adiponectin to induce insulin resistance in maternal and fetal tissues. Increased concentrations of tumor necrosis factor-alpha and interleukin-6 enhance expression and activity of 11beta-hydroxysteroid dehydrogenase type 1 enzyme, which produces abdominal obesity, insulin resistance, hyperlipidemia, hyperphagia, and hyperleptinemia, characteristic features of metabolic syndrome X. Continued consumption of an energy-dense diet in childhood aggravates these molecular events. This implies that supplementation of long-chain polyunsaturated fatty acids (especially AA, EPA, and DHA in appropriate ratios) from the perinatal period through adulthood could prevent, arrest, or postpone development of metabolic syndrome X.

Essential fatty acids and their derivatives

PURPOSE OF REVIEW

This review will address recent research in metabolism of essential fatty acids and their long chain derivatives. Our main focus will be the association between essential fatty acid status and various disease states, as well as the effects of supplementation with essential fatty acids or their derivatives on a number of clinical outcomes.

RECENT FINDINGS

There have been several papers over the last few years that show links between supplementation with fish oil (n-3 polyunsaturated fatty acids) and cardiovascular disease. Recent data suggest that the use of fish oil (containing n-3 fatty acids) in a variety of disorders such as cystic fibrosis, coronary disease and in the prevention of sudden death is beneficial. Several papers show reductions in systemic markers of inflammation. More widespread use of essential fatty acid derivatives in infant formula can certainly be questioned on the basis of the recent data. Fewer benefits are seen with ingestion of the essential fatty acids themselves, likely related to limited conversion to their long chain derivatives in humans.

SUMMARY

Derivatives of essential fatty acids have the potential to modify a number of disease states, either ingested in greater quantities in the diet, or taken as supplements in the form of fish oil.

Fetal growth restriction: a workshop report

Intrauterine growth restriction (IUGR) is associated with significantly increased perinatal morbidity and mortality as well as cardiovascular disease and glucose intolerance in adult life. A number of disorders from genetic to metabolic, vascular, coagulative, autoimmune, as well as infectious, can influence fetal growth by damaging the placenta, leading to IUGR as a result of many possible fetal, placental and maternal disorders. Strict definitions of IUGR and of its severity are needed in order to eventually distinguish among different phenotypes, such as gestational age at onset, degree of growth restriction and presence of hypoxia. This report explores and reviews some of the most recent developments in both clinical and basic research on intrauterine growth restriction, by seeking mechanisms that involve genetic factors, utero-placental nutrient availability and vascular growth factors. New exciting findings on the genomic imprinting defects potentially associated with IUGR, and the placental anomalies associated with the decreased nutrient transport are summarized. Moreover, recent data on angiogenic growth factors as well as new information arising from application of gene chip technologies are discussed.

Visual evoked potentials in disproportionately growth-retarded human neonates

To study brain function in the neonatal period, disproportionately growth-retarded (n = 33) and appropriately grown (n = 21) infants were examined using Doppler flow velocities prenatally and visual evoked potentials postnatally. Visual evoked potentials recordings were made at gestation of 40 and 46 weeks. The group of growth-retarded infants had significantly prolonged latencies to both of the two major peaks (designated P and N), most pronounced for the P peak. This result was observed at both ages investigated and corresponds to a developmental delay of 3 weeks. For individuals, the increase in P latency correlated to prenatal flow indices and to neonatal anthropometric parameters indicative of growth retardation. We conclude that in utero growth retardation affects brain development as assessed by visual evoked potentials in the neonatal period. This developmental delay may be produced by intracerebral factors during the process of growth retardation, and these alterations may have a prognostic value.

The source of long-chain PUFA in formula supplements does not affect the fatty acid composition of plasma lipids in full-term infants

Supplementation of formulas for full-term infants with long-chain (LC) PUFA [arachidonic acid (AA) and docosahexaenoic acid (DHA)] at levels resembling human milk is recommended because they provide biochemical and functional benefits to the neonate. The objective of this work was to determine whether the source of dietary LC-PUFA affects the bioavailability in full-term infants. Treatment groups were as follows: full-term infants were fed from birth to 3 mo breast-milk (n = 11, 0.4 and 0.3 g/100 g total fatty acids as AA and DHA, respectively), formula containing LC-PUFA in the form of egg phospholipids (n = 12), or a formula supplemented with LC-PUFA in the form of triglycerides synthesized by single cells of algal and fungal microorganisms (n = 12). Both formulas provided 0.4 and 0.1 g/100 g total fatty acids as AA and DHA, respectively. We compared the fatty acid compositions of the main plasma lipid fractions (phospholipids, triglycerides, and cholesteryl esters) at birth and 3 mo. At 3 mo, lower levels of nervonic acid (NA), docosapentaenoic (DPA) acid, and DHA were found in all plasma lipid fractions from infants fed formula compared with those in the human milk-fed infants, irrespective of the source of the formula supplement (P < 0.02). These data demonstrate that the form of dietary LC-PUFA (triglycerides or phospholipids) does not influence their bioavailability. Similarly, absorption of LC-PUFA depends mainly on the lipid composition of the diet fed. These results suggest that the levels of NA, DPA, and DHA in formulas for full-term infants should be increased.

Relationship between plasma fatty acid profile and antioxidant vitamins during normal pregnancy

OBJECTIVE

To study the changes of plasma fatty acids and lipophilic vitamins during normal pregnancy.

DESIGN

Plasma fatty acid profile and the concentration of carotenoids, tocopherols and retinol were measured in healthy women at the first and third trimesters of pregnancy, at delivery, and in cord blood plasma.

RESULTS

Maternal plasma cholesterol and triglycerides increased from the first to the third trimester of gestation, while free fatty acids progressively increased from the first trimester through the third trimester to delivery, suggesting an enhanced lipolytic activity. Plasma levels of alpha- and gamma-tocopherols, lycopene and beta-carotene also progressively increased with gestation, but values in cord blood plasma were lower than in mothers at delivery. Retinol levels declined with gestational time and values in cord blood plasma were even lower. The proportion of total saturated fatty acids increased with gestation, and it further increased in cord blood plasma. Total n-9 fatty acids remained stable throughout pregnancy, and slightly declined in cord blood plasma, the change mainly corresponding to oleic acid. Total n-6 fatty acids declined with gestation and further decreased in cord blood plasma, and a similar trend was found for linoleic acid. However, arachidonic acid declined in women at the third trimester and at delivery as compared to the first trimester, but was enhanced in cord blood plasma. The proportion of total n-3 fatty acids remained stable throughout pregnancy at the expense of decreased alpha-linolenic acid at delivery but enhanced eicosapentaenoic acid, with small changes in docosahexaenoic acid. The proportion of these n-3 fatty acids was similar in cord blood plasma and maternal plasma at delivery.

CONCLUSIONS

Owing to the different placental transfer mechanisms and fetal capability to metabolize some of the transferred fatty acids and lipophilic vitamins, the fetus preserves the essential compounds to assure their appropriate availability to sustain its normal development and to protect itself from the oxidative stress of extrauterine life.

SPONSORSHIP

The studies reported herein have been carried out with financial support from the Commission of the European Communities, specific RTD programme 'Quality of Life and Management of Living Resources', QLK1-2001-00138 'Influence of Dietary Fatty Acids on the Pathophysiology of Intrauterine Foetal Growth and Neonatal Development' (PeriLip). It does not necessarily reflect its views and in no way anticipates the Commission's future policy in this area.