Essential Fatty Acids Interconversion in the Human Fetal Liver

Chambaz, Jean; Ravel, Denis; Manier, Marie-C.; Pépin, Dominique; Mulliez, N; Béréziat, G.

doi:10.1159/000242104

Cited by 140 publications

(69 citation statements)

References 8 publications

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“…Clark and colleagues (Cho et al, 1999) have measured delta-5 desaturase and delta-5 desaturase mRNA in human placental tissue although the levels were relatively low compared to other tissues and other workers have been unable to detect any delta-6 or delta-5 desaturase activity in human placental tissue (Chambaz et al, 1985). Similarly, two studies in the perfused placenta demonstrated no detectable chain elongation and desaturation of either LA or aLN (Booth et al, 1981;Haggarty et al, 1997).…”

Section: Synthesis Of Lcpufamentioning

confidence: 99%

Effect of placental function on fatty acid requirements during pregnancy

Haggarty¹

2004

Eur J Clin Nutr

187

156

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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.

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Section: Synthesis Of Lcpufamentioning

confidence: 99%

Effect of placental function on fatty acid requirements during pregnancy

Haggarty¹

2004

Eur J Clin Nutr

187

156

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“…One possible mechanism for this phenomenon is endogenous fetal desaturase activity (Chambaz et al 1985, Salem et al 1996, Su et al 2001.The enzymes D5-desaturase (D5D) and D6-desaturase (D6D) modify fatty acid structure by introducing a double bond at the D5 and D6 positions, respectively. This reaction limits the rate of de novo LCPUFA synthesis, with reduced desaturase activity causing lower tissue LCPUFA abundance in rats (De Tomas et al 1980).…”

Section: Introductionmentioning

confidence: 99%

The effect of fetal pig size and stage of gestation on tissue fatty acid metabolism and profile

McNeil¹,

Finch²,

Page³

et al. 2005

Reproduction

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The fetus requires an adequate supply of fatty acids for optimum growth and development. It has been hypothesized that reduced activity of enzymes of fatty acid metabolism could contribute to inadequate fetal growth. In a porcine model of differential fetal growth we examined heart and liver fatty acid synthase, D5-desaturase and D6-desaturase gene expression and measured hepatic fatty acid profile to assess long-chain polyunsaturated fatty acid status. On gestation days 45, 65 and 100 sows were killed and tissues extracted from an average-sized fetus and the smallest fetus from each litter. As early as day 45, considerable hepatic D5-and D6-desaturase was detected, and this expression significantly increased as gestation progressed. In contrast, cardiac desaturase expression remained stable with time. Fatty acid synthase expression was greatest at day 65 in the liver, but was not expressed in the heart. Overall, the smallest fetus did not exhibit reduced tissue D5-or D6-desaturase expression or compromised polyunsaturated fatty acid status at any stage. In fact, small fetuses expressed more cardiac D5-desaturase than their average-sized siblings, possibly in response to a stress to the heart. It is clear from this study that fatty acid metabolism changes markedly as gestation progresses, and reduced fatty acid supply does not cause inadequate growth in this porcine model of fetal development.

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“…The source of the EFA-derivative long-chain PUFAs arachidonic acid (ARA) and docosahexaonic acid (DHA) is primarily of maternal origin, as the placenta lacks or has only minor activity of the enzymes (d5-and d6-desaturase) for converting EFAs into long-chain PUFAs (2)(3)(4)(5). However, infants born premature have been suggested to be able to synthesize both ARA and DHA at an age when they should be developmentally dependent on the placenta (6,7).…”

mentioning

confidence: 99%

Gestational and hormonal regulation of human placental lipoprotein lipase

Magnusson-Olsson

Hamark

Ericsson

et al. 2006

Journal of Lipid Research

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The fetal demand for FFA increases as gestation proceeds, and LPL represents one potential mechanism for increasing placental lipid transport. We examined LPL activity and protein expression in first trimester and term human placenta. The LPL activity was 3-fold higher in term (n 5 7; P , 0.05) compared with first trimester (n 5 6) placentas. The LPL expression appeared lower in microvillous membrane from first trimester (n 5 2) compared with term (n 5 2) placentas. We incubated isolated placental villous fragments with a variety of effectors [GW 1929, estradiol, insulin, cortisol, epinephrine, insulin-like growth factor-1 (IGF-1), and tumor necrosis factor-a] for 1, 3, and 24 h to investigate potential regulatory mechanisms. Decreased LPL activity was observed after 24 h of incubation with estradiol (1 mg/ml), insulin, cortisol, and IGF-1 (n 5 12; P , 0.05). We observed an increase in LPL activity after 3 h of incubation with estradiol (20 ng/ml) or hyperglycemic medium plus insulin (n 5 7; P , 0.05).

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Essential Fatty Acids Interconversion in the Human Fetal Liver

Cited by 140 publications

References 8 publications

Effect of placental function on fatty acid requirements during pregnancy

Effect of placental function on fatty acid requirements during pregnancy

The effect of fetal pig size and stage of gestation on tissue fatty acid metabolism and profile

Gestational and hormonal regulation of human placental lipoprotein lipase

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