Lipid metabolism in vertebrate retinal rod outer segments

Giusto, Norma M.; Pasquaré, Susana J.; Salvador, Gabriela Alejandra; Castagnet, P.I.; Roque, Marta Elena; Boschero, Mónica G. Ilincheta de

doi:10.1016/s0163-7827(00)00009-6

Cited by 111 publications

(64 citation statements)

References 441 publications

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“…In contrast, we have found PE-4-HHE Michael adducts, resulting from n-3 fatty acid peroxidation, in retinas that are especially rich in DHA (27). Indeed, our results indicate that in diabetic rat retinas, DHA represented 28.3% and 38.4% of total phospholipids and PEs, respectively, whereas AA was 4-fold lower.…”

Section: Discussioncontrasting

confidence: 64%

Evidence for in situ ethanolamine phospholipid adducts with hydroxy-alkenals

Bacot

Bernoud-Hubac

Chantegrel

et al. 2007

Journal of Lipid Research

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Hydroxy-alkenals, such as 4-hydroxy-2(E )-nonenal (4-HNE; from n-6 fatty acids), are degradation products of fatty acid hydroperoxides, including those generated by free radical attack of membrane polyunsaturated fatty acyl moieties. The cytotoxic effects of hydroxy-alkenals are well known and are mainly attributable to their interaction with different molecules to form covalent adducts. Indeed, ethanolamine phospholipids (PEs) can be covalently modified in a cellular system by hydroxy-alkenals, such as 4-HNE, 4-hydroxy-2(E)-hexenal (4-HHE; from n-3 fatty acids), and 4-hydroxy-dodecadienal (4-HDDE; from the 12-lipoxygenase product of arachidonic acid), to form mainly Michael adducts. In this study, we describe the formation of PE Michael adducts in human blood platelets in response to oxidative stress and in retinas of streptozotocin-induced diabetic rats. We have successfully characterized and evaluated, for the first time, PEs coupled with 4-HHE, 4-HNE, and 4-HDDE by gas chromatography-mass spectrometry measurement of their ethanolamine moieties. We also report that aggregation of isolated human blood platelets enriched with PE-4-hydroxy-alkenal Michael adducts was altered. These data suggest that these adducts could be used as specific markers of membrane disorders occurring in pathophysiological states with associated oxidative stress and might affect cell function.-Bacot, S., N. Bernoud-Hubac, B. Chantegrel, C. Deshayes, A. Doutheau, G. Ponsin, M. Lagarde, and M. Guichardant. Evidence for in situ ethanolamine phospholipid adducts with hydroxy-alkenals. J. Lipid Res. 2007. 48: 816-825.

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Section: Discussioncontrasting

confidence: 64%

Evidence for in situ ethanolamine phospholipid adducts with hydroxy-alkenals

Bacot

Bernoud-Hubac

Chantegrel

et al. 2007

Journal of Lipid Research

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“…1,2 DHA is the major polyunsaturated fatty acid in the outer segments of the retina rods and cones, where it can constitute as much as 50% of the fatty acids in phosphatidylethanolamine (PE) and phosphatidylserine (PS), and as much as 80% of all the polyunsaturated fatty acids. 1 These membranes are specialized for the rapid transmission of light and contain 90% to 95% of the lipid as phospholipid. The phospholipids contain unusual PE, PS, and phosphatidylcholine (PC) species in which both acyl groups are DHA.…”

mentioning

confidence: 99%

Perinatal biochemistry and physiology of long-chain polyunsaturated fatty acids

Innis

2003

The Journal of Pediatrics

439

287

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Docosahexaenoic acid (DHA) and arachidonic acid (ARA) are important structural components of the central nervous system. These fatty acids are transferred across the placenta, are present in human milk, and are accumulated in the brain and retina during fetal and infant development. The high concentrations of DHA in the retina and of DHA and ARA in brain gray matter suggests that these fatty acids have important roles in retinal and neural function. Animal studies have shown that depletion of DHA from the retina and brain results in reduced visual function and learning deficits. The latter effects may be explained by changes in the membrane bilayer that alter membrane-associated receptors and signal transduction systems, ion channel activity, or direct effects on gene expression. DHA can be formed in the liver from alpha linolenic acid, but it is unclear if the rate of DHA synthesis in humans is sufficient to support optimal brain and retinal development. Although there is no evidence that the ability to form ARA from linoleic acid is limiting, supplementation with DHA reduces tissue ARA, possibly creating a conditional need for ARA in infants with a dietary intake of DHA. The amount of DHA in human milk varies widely and is positively correlated with visual and language development in breast-fed infants. Advances in understanding essential fatty acid requirements will benefit from intervention studies that use functionally relevant tests to probe the deficiency or adequacy of physiologically important pools of DHA and ARA in developing infants. (J Pediatr 2003;143:S1-S8) D ocosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (ARA, 20:4n-6) are important structural components of the highly specialized membranes lipids of the human central nervous system. 1,2 DHA is the major polyunsaturated fatty acid in the outer segments of the retina rods and cones, where it can constitute as much as 50% of the fatty acids in phosphatidylethanolamine (PE) and phosphatidylserine (PS), and as much as 80% of all the polyunsaturated fatty acids.1 These membranes are specialized for the rapid transmission of light and contain 90% to 95% of the lipid as phospholipid. The phospholipids contain unusual PE, PS, and phosphatidylcholine (PC) species in which both acyl groups are DHA. Approximately 10% of the weight of the brain, and 50% of the dry weight, is lipid. About half of this lipid is phospholipid, with approximately 20% cholesterol, 15% to 20% cerebrosides, and smaller amounts of sulphatides and gangliosides.2 The phospholipids of brain gray matter contain high proportions of DHA in PE and PS and high amounts of ARA in phosphatidylinositol (PI). ARA is also present in membrane phospholipids, particularly in PI throughout the body. Unlike other organs, the dietary essential fatty acid linoleic acid (LA, 18:2n-6) usually represents <1% of brain and retina fatty acids, and concentrations of a-linolenic acid (18:3n-3) are even lower. 2These usual characteristics of brain and retina phospholipids suggest that specific mechanisms ...

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“…9,[11][12][13][14]16,19 There are hypothetical potential explanations that may explain this situation, as the presence of high levels of DHA in the outer segment of cones and rods membranes, possibly providing both a protective and cell proliferation function. 27,28 Moreover, antioxidants like vitamin A, E and carotenoids might have a protective effect against photoreceptor cells membrane degeneration. 29 Although in an analysis of the selected studies might suggest a protective effect of vitamin A on ERG when assessed by 30 Hz amplitude decline, 12 this effect did not show on other ERG parameters or other outcomes such as visual acuity and visual field measurements.…”

Section: Discussionmentioning

confidence: 99%