Diet (n-3) polyunsaturated fatty acid content and parity affect liver and erythrocyte phospholipid fatty acid composition in female rats

The relationship between plasma free fatty acids, cognitive function and structural integrity of the brain in middle-aged healthy humans

Background: The cerebral composition of ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) is believed to influence cognitive function and structural damage of the aging brain. However, existing data is inconsistent.

Materials and Methods: This retrospective study explored the association between free plasma PUFA concentrations, cognitive function and brain structure atrophy in a well-characterized community-dwelling cohort of elderly individuals without stroke and dementia. Ten different fatty acids were analyzed in stored plasma samples from 391 non-demented elderly individuals by gas chromatography mass spectrometry. Neuropsychiatric tests capturing memory, executive function and visuopractical skills were performed in all participants. Brain atrophy was assessed by MRI in a subset of 167 individuals.

Results: Higher plasma concentrations of free ω-6 PUFAs (p = 0.042), and, in particular, linoleic acid (p = 0.01), were significantly associated with lower executive function. No significant association existed between ω-3 PUFA concentrations and cognitive functioning. The volume of the frontal lobes was inversely associated with ω-6 PUFAs, whereas ω-3 PUFAs were positively related with temporal lobe volumes. All associations did not withstand correction for multiple comparisons.

Conclusions: Our study suggests subtle effects of PUFA imbalances on cognition and brain structure. Yet the observed associations are weak and unlikely to be of clinical relevance. The brain regions that seem to be most sensitive to imbalances of ω-3 and ω-6 PUFAs are the frontal and temporal lobes.

Perinatal dietary omega-3 fatty acid deficiency reduces maternal nurturing behavior in rats: dissociation from elevated pro-inflammatory signaling

Objectives: Maternal-pup nurturing behavior has previously been shown to impact offspring neurodevelopment independent of diet. Here we investigated the effects of perinatal maternal n-3 fatty acid deficiency on maternal-pup nurturing behavior and potential associations with pro-inflammatory signaling.Methods: Eight-week-old virgin female Long-Evans hooded rats were randomized to a control diet containing alpha-linolenic acid (ALA, 18:3n-3) (CON, n = 10) or an ALA-free diet (Deficient, DEF, n = 11) 30 d prior to mating. On postnatal day 2 (P2) litters were culled to eight per dam. On P3, P6, and P9 dams and their litters were video recorded and maternal nurturing behaviors, including licking/grooming of pups and arched-back nursing, were scored by a blinded rater. Following weaning on P21, dam postmortem central (prefrontal cortex, PFC) and peripheral (red blood cell, RBC) fatty acid composition and central (PFC IL-1β, IL-2, IL-6, TNFα, cPLA₂, COX-2 mRNA) and peripheral (plasma IL-1β, IL-2, IL-6, TNFα, CRP) pro-inflammatory biostatus assessed.Results: DEF dams exhibited significantly lower RBC (p ≤ 0.0001) and PFC (p ≤ 0.0001) docosahexaenoic acid (DHA) levels compared with CON dams. Irrespective of diet dams exhibited significantly lower RBC, but not PFC, DHA levels compared with non-parous rats. DEF dams exhibited less licking/grooming (p = 0.008), arched-back nursing (p ≤ 0.0001) and blanket nursing (p = 0.003), and exhibited more passive nursing (p = 0.003) but not time off pups (p = 0.1), compared with CON dams. PFC and plasma inflammatory measures did not differ significantly between groups.Discussion: Perinatal dietary n-3 fatty acid deficiency reduces maternal nurturing behavior and this effect is not associated with enduring elevations in pro-inflammatory signaling.

N-3 (Omega-3) Fatty Acids: Effects on Brain Dopamine Systems and Potential Role in the Etiology and Treatment of Neuropsychiatric Disorders

BACKGROUND & OBJECTIVE

A number of neuropsychiatric disorders, including Parkinson's disease, schizophrenia, attention deficit hyperactivity disorder, and, to some extent, depression, involve dysregulation of the brain dopamine systems. The etiology of these diseases is multifactorial, involving genetic and environmental factors. Evidence suggests that inadequate levels of n-3 (omega- 3) polyunsaturated fatty acids (PUFA) in the brain may represent a risk factor for these disorders. These fatty acids, which are derived from the diet, are a major component of neuronal membranes and are of particular importance in brain development and function. Low levels of n-3 PUFAs in the brain affect the brain dopamine systems and, when combined with appropriate genetic and other factors, increase the risk of developing these disorders and/or the severity of the disease. This article reviews the neurobiology of n-3 PUFAs and their effects on dopaminergic function.

CONCLUSION

Clinical studies supporting their role in the etiologies of diseases involving the brain dopamine systems and the potential of n-3 PUFAs in the treatment of these disorders are discussed.

Comparative analyses of DHA-Phosphatidylcholine and recombination of DHA-Triglyceride with Egg-Phosphatidylcholine or Glycerylphosphorylcholine on DHA repletion in n-3 deficient mice

Background

Docosahexaenoic acid (DHA) is important for optimal neurodevelopment and brain function during the childhood when the brain is still under development.

Methods

The effects of DHA-Phosphatidylcholine (DHA-PC) and the recombination of DHA-Triglyceride with egg PC (DHA-TG + PC) or α-Glycerylphosphorylcholine (DHA-TG + α-GPC) were comparatively analyzed on DHA recovery and the DHA accumulation kinetics in tissues including cerebral cortex, erythrocyte, liver, and testis were evaluated in the weaning n-3 deficient mice.

Results

The concentration of DHA in weaning n-3 deficient mice could be recovered rapidly by dietary DHA supplementation, in which DHA-PC exhibited the better efficacy than the recombination of DHA-Triglyceride with egg PC or α-GPC. Interestingly, DHA-TG + α-GPC exhibited the greater effect on DHA accumulation than DHA-TG + PC in cerebral cortex and erythrocyte (p < 0.05), which was similar to DHA-PC. Meanwhile, DHA-TG + PC showed a similar effect to DHA-PC on DHA repletion in testis, which was better than that of DHA-TG + α-GPC (p < 0.05).

Conclusion

We concluded that different forms of DHA supplements could be applied targetedly based on the DHA recovery in different tissues, although the supplemental effects of the recombination of DHA-Triglyceride with egg PC or α-GPC were not completely equivalent to that of DHA-PC, which could provide some references to develop functional foods to support brain development and function.

An Increased Dietary Supply of Medium-Chain Fatty Acids during Early Weaning in Rodents Prevents Excessive Fat Accumulation in Adulthood

Medium-chain fatty acids (MCFA) are a directly and readily absorbed source of energy. Exposure early-in-life to increased MCFA levels might affect development and impact (lipid) metabolism later in life. We tested whether an increased MCFA intake early-in-life positively affects adult body composition and metabolic status when challenged by a western-style diet (WSD). Male offspring of C57Bl/6j mice and Wistar rats were fed a control diet (CTRL; 10 w% fat, 14% MCFA) or a medium-chain triglycerides (MCT) diet with 20% MCFA until postnatal (PN) day 42, whereupon animals were fed a WSD (10 w% fat) until PN day 98. Body composition was monitored by Dual Energy X-ray Absorptiometry (DEXA). In rats, glucose homeostasis was assessed by glucose tolerance test (GTT) and insulin tolerance test (ITT); in mice, the HOmeostasis Model Assessment of Insulin Resistance (HOMA-IR) was calculated. At autopsy on PN day 98, plasma lipid profiles, glucose, insulin, and adipokines were measured; organs and fat pads were collected and the adipocyte size distribution was analysed. Milk analysis in mice showed that the maternal MCT diet was not translated into milk, and pups were thus only exposed to high MCT levels from early weaning onward: PN day 16 until 42. Mice exposed to MCT showed 28% less fat accumulation vs. CTRL during WSD. The average adipocyte cell size, fasting plasma triglycerides (TG), and leptin levels were reduced in MCT mice. In rats, no effects were found on the adult body composition, but the adipocyte cell size distribution shifted towards smaller adipocytes. Particularly mice showed positive effects on glucose homeostasis and insulin sensitivity. Increased MCFA intake early-in-life protected against the detrimental effects of an obesogenic diet in adulthood.

Increased intake of vegetable oil rich in n-6 PUFA enhances allergic symptoms and prevents oral tolerance induction in whey-allergic mice

Increased intake of vegetable oils rich in n-6 PUFA, including soyabean oil, has been associated with an increase in allergic disease. The present study aimed to determine the effect of an increasing dose of dietary vegetable oil on allergic outcomes in mice. To study this, mice received a 7 v. 10 % soyabean oil diet before and during oral sensitisation with whey or whey hyperimmune serum transfer. Another group of mice received partial whey hydrolysate (pWH) while being fed the diets before oral sensitisation. The acute allergic skin response, serum Ig level, mouse mast cell protease-1 (mMCP-1) concentration and/or splenic T-cell percentages were determined upon whey challenge. When the diets were provided before and during oral sensitisation, the acute allergic skin response was increased in mice fed the 10 % soyabean oil diet compared with the 7 % soyabean oil diet. Whey IgE and IgG1 levels remained unaltered, whereas mMCP-1 levels increased in mice fed the 10 % soyabean oil diet. Furthermore, allergic symptoms were increased in naive mice fed the 10 % soyabean oil diet and sensitised with whey hyperimmune serum. In addition to enhancing the mast cell response, the 10 % soyabean oil diet increased the percentage of activated Th1 and Th2 cells as well as increased the ratios of Th2:regulatory T cells and Th2:Th1 when compared with the 7 % soyabean oil diet. Oral tolerance induction by pWH was abrogated in mice fed the 10 % soyabean oil diet compared with those fed the 7 % soyabean oil diet during pretreatment with pWH. In conclusion, increased intake of soyabean oil rich in n-6 PUFA suppresses tolerance induction by pWH and enhances the severity of the allergic effector response in whey-allergic mice. Dietary vegetable oils rich in n-6 PUFA may enhance the susceptibility to develop or sustain food allergy.

Reduced linoleic acid intake in early postnatal life improves metabolic outcomes in adult rodents following a Western-style diet challenge

The global increase in dietary n-6 polyunsaturated fatty acid (PUFA) intake has been suggested to contribute to the rise in obesity incidence. We hypothesized that reduced n-6 PUFA intake during early postnatal life improves adult body composition and metabolic phenotype upon a Western diet challenge. Male offspring of C57Bl/6j mice and Wistar rats were subjected to a control diet (CTRL; 3.16 En% linoleic acid [LA]) or a low n-6 PUFA diet (low LA; 1.36 En% LA) from postnatal days (PNs) 2 to 42. Subsequently, all animals were switched to a Western-style diet (2.54 En% LA) until PN98. We monitored body composition by dual-energy x-ray absorptiometry and glucose homeostasis by an intravenous glucose and insulin tolerance test in rats and by the homeostasis model assessment of insulin resistance (HOMA-IR) in mice. At PN98, plasma lipids, glucose, insulin, and adipokines were measured and adipocyte number and size were analyzed. In mice, the postnatal low-LA diet decreased fat accumulation during the adult Western-style diet challenge (-27% compared with CTRL, P < .001). Simultaneously, it reduced fasting triglyceride levels and lowered fasting resistin and leptin levels. In rats, the low-LA diet did not affect adult body composition, but decreased the number of retroperitoneal adipocytes and increased the number of large adipocytes. In conclusion, lowering dietary n-6 PUFA intake in early life protected against detrimental effects of an obesogenic diet in adulthood on metabolic homeostasis and fat mass accumulation.

Dietary Marine n-3 PUFAs Do Not Affect Stress-Induced Visceral Hypersensitivity in a Rat Maternal Separation Model

BACKGROUND

Although never evaluated for efficacy, n-3 (ω-3) long-chain polyunsaturated fatty acids (LCPUFAs) are commercially offered as treatment for irritable bowel syndrome (IBS).

OBJECTIVE

This study was designed to investigate, in a mast cell-dependent model for visceral hypersensitivity, whether this pathophysiologic mechanism can be reversed by dietary LCPUFA treatment via peroxisome proliferator-activated receptor γ (PPARG) activation.

METHODS

Maternally separated rats were subjected to hypersensitivity-inducing acute stress at adult age. Reversal was attempted by protocols with tuna oil-supplemented diets [4% soy oil (SO) and 3% tuna oil (SO-T3) or 3% SO and 7% tuna oil (SO-T7)] and compared with control SO diets (7% or 10% SO) 4 wk after stress. The PPARG agonist rosiglitazone was evaluated in a 1 wk preventive protocol (30 mg · kg⁻¹ · d⁻¹). Erythrocytes were assessed to confirm LCPUFA uptake and tissue expression of lipoprotein lipase and glycerol kinase as indicators of PPARG activation. Colonic mast cell degranulation was evaluated by toluidine blue staining. In vitro, human mast cell line 1 (HMC-1) cells were pretreated with rosiglitazone, eicosapentaenoic acid, or docosahexaenoic acid, stimulated with phorbol 12-myristate 13-acetate (PMA) and calcium ionophore or compound 48/80 and evaluated for tumor necrosis factor α (TNF-α) and β-hexosaminidase release.

RESULTS

Stress led to visceral hypersensitivity in all groups. Hypersensitivity was not reversed by SO-T3 or control treatment [prestress vs. 24 h poststress vs. posttreatment area under the curve; 76 ± 4 vs. 128 ± 12 (P < 0.05) vs. 115 ± 14 and 82 ± 5 vs. 127 ± 16 (P < 0.01) vs. 113 ± 19, respectively]. Comparison of SO-T7 with its control showed similar results [74 ± 6 vs. 103 ± 13 (P < 0.05) vs. 115 ± 17 and 66 ± 3 vs. 103 ± 10 (P < 0.05) vs. 117 ± 11, respectively]. Erythrocytes showed significant LCPUFA uptake in the absence of colonic PPARG activation. Rosiglitazone induced increased PPARG target gene expression, but did not prevent hypersensitivity. Mast cell degranulation never differed between groups. Rosiglitazone and LCPUFAs significantly reduced PMA/calcium ionophore-induced TNF-α release but not degranulation of HMC-1 cells.

CONCLUSION

Dietary LCPUFAs did not reverse stress-induced visceral hypersensitivity in maternally separated rats. Although further research is needed, claims concerning LCPUFAs as a treatment option in IBS cannot be confirmed at this point and should be regarded with caution.

DHA-rich tuna oil effectively suppresses allergic symptoms in mice allergic to whey or peanut

BACKGROUND

Supplementation with long-chain n-3 polyunsaturated fatty acids (LCPUFAs) has been found to reduce the development of allergic disease.

OBJECTIVE

The aim of this study was to compare the effectiveness of fish oil diets rich in eicosapentaenoic acid (20:5n-3; EPA) or docosahexaenoic acid (22:6n-3; DHA) in suppressing food allergic symptoms.

METHODS

Mice were fed a control diet (10% soybean oil) or fish oil diet rich in EPA (4% soybean oil + 6% EPA oil containing 28.8% EPA and 13.7% DHA) or DHA (4% soybean oil + 6% DHA oil containing 7% EPA and 27.8% DHA), starting 14 d before and for 5 wk during oral sensitization with peanut extract (PE) or whey. Acute allergic skin responses, serum immunoglobulins (Igs), and mucosal mast cell protease-1 (mmcp-1) were assessed. Hyperimmune serum was transferred to naive recipient mice fed the different diets.

RESULTS

The DHA diet effectively reduced the acute allergic skin response compared with the control or EPA diet in PE-allergic mice (control, 159 ± 15, or EPA, 129 ± 8, vs. DHA, 78 ± 7 μm; P < 0.0001 or P < 0.05, respectively). In contrast, both the DHA and EPA diets reduced the allergic skin response in whey allergic mice (control, 169 ± 9, vs. DHA, 91 ± 13, or EPA, 106 ± 14 μm; P < 0.001 or P < 0.01, respectively); however, only the DHA diet reduced mmcp-1 and whey-specific IgE and IgG1. The DHA and EPA diets also reduced the acute skin response in passively immunized mice.

CONCLUSIONS

The DHA-rich fish oil diet reduced allergic sensitization to whey and allergic symptoms in both PE- and whey-allergic mice. These data suggest that DHA-rich fish oil is useful as an intervention to prevent or treat food allergy symptoms.

Dietary fish oil improves endothelial function and lowers blood pressure via suppression of sphingolipid-mediated contractions in spontaneously hypertensive rats

OBJECTIVE

Long-chain n-3 polyunsaturated fatty acids from oily fish reduce blood pressure (BP) in hypertension. Previously, we demonstrated that hypertension is associated with marked alterations in sphingolipid biology and elevated ceramide-induced vasoconstriction. Here we investigated in spontaneously hypertensive rats (SHRs) whether fish oil improves endothelial function including reduced vascular contraction induced via the sphingolipid cascade, resulting in reduced BP.

METHODS

Twelve-week-old SHRs were fed a control or fish oil-enriched diet during 12 weeks, and BP was recorded. Plasma sphingolipid levels were quantified by mass spectrometry and the response of isolated carotid arteries towards different stimuli was measured. Furthermore, erythrocyte membrane fatty acid composition, thromboxane A2 formation and cytokine secretion in ex-vivo lipopolysaccharide-stimulated thoracic aorta segments were determined.

RESULTS

The fish oil diet reduced the mean arterial BP (P < 0.001) and improved endothelial function, as indicated by a substantially increased relaxation potential towards ex-vivo methacholine exposure of the carotid arteries (P < 0.001). The long-chain n-3 polyunsaturated fatty acid diet resulted in altered levels of specific (glucosyl)ceramide subspecies (P < 0.05), reduced membrane arachidonic acid content (P < 0.001) and decreased thromboxane concentrations in plasma (P < 0.01). Concomitantly, the fish oil diet largely reduced ceramide-induced contractions (P < 0.01), which are predominantly mediated by thromboxane. Furthermore, thromboxane A2 and interleukin-10 were reduced in supernatants of lipopolysaccharide-stimulated thoracic aorta of SHRs fed the fish oil diet while RANTES (regulated on activation, normal T-cell expressed and secreted) was enhanced. This may contribute to reduced vasoconstriction in vivo.

CONCLUSIONS

Dietary fish oil lowers BP in SHRs and improves endothelial function in association with suppression of sphingolipid-dependent vascular contraction.

Dietary long chain n-3 polyunsaturated fatty acids prevent impaired social behaviour and normalize brain dopamine levels in food allergic mice

Allergy is suggested to exacerbate impaired behaviour in children with neurodevelopmental disorders. We have previously shown that food allergy impaired social behaviour in mice. Dietary fatty acid composition may affect both the immune and nervous system. The aim of this study was to assess the effect of n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) on food allergy-induced impaired social behaviour and associated deficits in prefrontal dopamine (DA) in mice. Mice were fed either control or n-3 LCPUFA-enriched diet before and during sensitization with whey. Social behaviour, acute allergic skin response and serum immunoglobulins were assessed. Monoamine levels were measured in brain and intestine and fatty acid content in brain. N-3 LCPUFA prevented impaired social behaviour of allergic mice. Moreover, n-3 LCPUFA supplementation increased docosahexaenoic acid (DHA) incorporation into the brain and restored reduced levels of prefrontal DA and its metabolites 3,4-dihydroxyphenylacetic acid, 3-methoxytyramine and homovanillic acid in allergic mice. In addition to these brain effects, n-3 LCPUFA supplementation reduced the allergic skin response and restored decreased intestinal levels of serotonin metabolite 5-hydroxyindoleacetic acid in allergic mice. N-3 LCPUFA may have beneficial effects on food allergy-induced deficits in social behaviour, either indirectly by reducing the allergic response and restoring intestinal 5-HT signalling, or directly by DHA incorporation into neuronal membranes, affecting the DA system. Therefore, it is of interest to further investigate the relevance of food allergy-enhanced impairments in social behaviour in humans and the potential benefits of dietary n-3 LCPUFA supplementation.

Dietary long chain n-3 polyunsaturated fatty acids prevent allergic sensitization to cow's milk protein in mice

BACKGROUND

Cow's milk allergy is one of the most common food allergies in children and no treatment is available. Dietary lipid composition may affect the susceptibility to develop allergic disease.

OBJECTIVE

Assess whether dietary supplementation with long chain n-3 polyunsaturated fatty acids (n-3 LCPUFA) prevents the establishment of food allergy.

METHODS

Mice were fed a control or fish oil diet before and during oral sensitization with whey. Acute allergic skin response, serum immunoglobulins as well as dendritic cell (DC) and T cell subsets in mesenteric lymph nodes (MLN), spleen and/or small intestine were assessed.

RESULTS

The acute allergic skin response was reduced by more than 50% in sensitized mice fed the fish oil diet compared to the control diet. In addition, anti-whey-IgE and anti-whey-IgG1 levels were decreased in the fish oil group. Serum transfer confirmed that the Th2-type humoral response was suppressed since sera of fish oil fed sensitized mice had a diminished capacity to induce an allergic effector response in naïve recipient mice compared to control sera. Furthermore, the acute skin response was diminished upon passive sensitization in fish oil fed naïve recipient mice. In addition, the percentage of activated Th1 cells was reduced by fish oil in spleen and MLN of sham mice. The percentage of activated Th2 cells was reduced in both sham- and whey-sensitized mice. In contrast, whey-sensitized mice showed an increased percentage of CD11b+CD103+CD8α- DC in MLN in association with enhanced FoxP3+ regulatory T cells (Treg) in spleen and intestine of fish oil fed whey-sensitized mice compared to sham mice.

CONCLUSIONS AND CLINICAL RELEVANCE

Dietary n-3 LCPUFA largely prevented allergic sensitization in a murine model for cow's milk allergy by suppressing the humoral response, enhancing local intestinal and systemic Treg and reducing acute allergic symptoms, suggesting future applications for the primary prevention of food allergy.

Postnatal dietary fatty acid composition permanently affects the structure of hypothalamic pathways controlling energy balance in mice

BACKGROUND

We previously reported that dietary lipid quality during early life can have long-lasting effects on metabolic health and adiposity. Exposure to a postnatal diet with low dietary omega-6 (n-6) or high omega-3 (n-3) fatty acid (FA) content resulted in reduced body fat accumulation when challenged with a moderate Western-style diet (WSD) beginning in adolescence.

OBJECTIVE

We determined whether this programming effect is accompanied by changes in hypothalamic neural projections or modifications in the postnatal leptin surge, which would indicate the altered development of hypothalamic circuits that control energy balance.

DESIGN

Neonatal mice were subjected to a control diet (CTR) or experimental diet with altered relative n-6 and n-3 FA contents [ie, a diet with a relative reduction in n-6 fatty acid (LOW n-6) or a diet with a relative increase in n-3 fatty acid (HIGH n-3) compared with the CTR from postnatal day (PN) 2 to 42].

RESULTS

Compared with CTR mice, mice fed a LOW n-6 or HIGH n-3 during postnatal life showed significant reductions in the density of both orexigenic and anorexigenic neural projections to the paraventricular nucleus of the hypothalamus at PN 28. These impairments persisted into adulthood and were still apparent after the WSD challenge between PNs 42 and 98. However, the neuroanatomical changes were not associated with changes in the postnatal leptin surge.

CONCLUSION

Although the exact mechanism remains to be elucidated, our data indicate that the quality of dietary FA during postnatal life affects the development of the central regulatory circuits that control energy balance and may do so through a leptin-independent mechanism.

Streptozotocin-induced diabetes partially attenuates the effects of a high-fat diet on liver and brain fatty acid composition in mice

The current study addresses the effects of a high-fat diet on liver and brain fatty acid compositions and the interaction of that diet with diabetes in a type 1 mouse model. Adult, male, normal and streptozotocin-induced diabetic C57BL/6 mice were fed standard (14 % kcal from fat) or high-fat (54 % kcal from fat, hydrogenated vegetable shortening and corn oil) diets for 8 weeks. Liver and whole brain total phospholipid fatty acid compositions were then determined by TLC/GC. In the liver of non-diabetic mice, the high-fat diet increased the percentages of 18:1n-9, 20:4n-6, and 22:5n-6 and decreased 18:2n-6 and 22:6n-3. Diabetes increased 16:0 in liver, and decreased 18:1n-7 and 20:4n-6. The effects of the high-fat diet on liver phospholipids in diabetic mice were similar to those in non-diabetic mice, or were of smaller magnitude. In the brain, the high-fat diet increased 18:0 and 20:4n-6 of non-diabetic, but not diabetic mice. Brain 22:5n-6 acid was increased by the high-fat diet in both non-diabetic and diabetic mice, but this increase was smaller in diabetic mice. Diabetes alone did not alter the percentage of any individual fatty acid in brain. This indicates that the effects of a high-fat diet on liver and brain phospholipid fatty acid compositions are partially attenuated by concomitant hyperglycemia with hypoinsulinemia.

Nutritional deficiencies and phospholipid metabolism

Phospholipids are important components of the cell membranes of all living species. They contribute to the physicochemical properties of the membrane and thus influence the conformation and function of membrane-bound proteins, such as receptors, ion channels, and transporters and also influence cell function by serving as precursors for prostaglandins and other signaling molecules and modulating gene expression through the transcription activation. The components of the diet are determinant for cell functionality. In this review, the effects of macro and micronutrients deficiency on the quality, quantity and metabolism of different phospholipids and their distribution in cells of different organs is presented. Alterations in the amount of both saturated and polyunsaturated fatty acids, vitamins A, E and folate, and other micronutrients, such as zinc and magnesium, are discussed. In all cases we observe alterations in the pattern of phospholipids, the more affected ones being phosphatidylcholine, phosphatidylethanolamine and sphingomyelin. The deficiency of certain nutrients, such as essential fatty acids, fat-soluble vitamins and some metals may contribute to a variety of diseases that can be irreversible even after replacement with normal amount of the nutrients. Usually, the sequelae are more important when the deficiency is present at an early age.

Phospholipid composition of erythrocytes and glutathione redox system in rats during adaptation to cholesterol load

We studied phospholipid composition of erythrocytes and the state of the glutathione redox system in rats during adaptation to cholesterol load for 180 days. The adaptive response is formed during the period from day 30 to day 90 of cholesterol load and is associated with increased relative content of phosphatidylethanolamine and phosphatidylinositol, activation of glutathione redox system enzymes (glutathione reductase and glutathione peroxidase), and enhanced production of glutathione.

N-3 long-chain polyunsaturated fatty acids prevent excessive fat deposition in adulthood in a mouse model of postnatal nutritional programming

This study investigates whether improved quality of nutrients during early postnatal life has effects on adult metabolic profile and body composition in a murine model of nutritional programming. Male offspring of C57Bl/6j dams received a diet containing 21% energy (En%) as fat of either 100% vegetable oils [control (CTRL)] or 80% vegetable oils/20% tuna fish oil [rich in n-3 long-chain polyunsaturated fatty acids (n-3 LCP)] from postnatal day (PN) 2 to 42. Subsequently, mice of both experimental groups were switched to a western style diet (WSD; 21 En% fat, high saturated fatty acid [FA] content, and cholesterol) until dissection at PN98. Body composition was analyzed by dual x-ray absorptiometry during the WSD challenge. Results showed that a n-3 LCP-rich diet during postnatal life not only reduced fat accumulation by ∼30% during the WSD challenge from PN42 to 98 (p < 0.001) but also led to a healthier plasma lipid profile, healthier plasma glucose homeostasis, and less hypertrophic adipocytes compared with CTRL. This study shows that postnatal nutrition has programming effects on adult body composition and metabolic homeostasis. In addition, it emphasizes that moderate alterations in fat quality during early postnatal life considerably affect adult metabolic health.

N-3 (omega-3) Fatty acids in postpartum depression: implications for prevention and treatment

A growing body of clinical and epidemiological evidence suggests that low dietary intake and/or tissue levels of n-3 (omega-3) polyunsaturated fatty acids (PUFAs) are associated with postpartum depression. Low tissue levels of n-3 PUFAs, particularly docosahexaenoic acid (DHA), are reported in patients with either postpartum or nonpuerperal depression. Moreover, the physiological demands of pregnancy and lactation put childbearing women at particular risk of experiencing a loss of DHA from tissues including the brain, especially in individuals with inadequate dietary n-3 PUFA intake or suboptimal metabolic capabilities. Animal studies indicate that decreased brain DHA in postpartum females leads to several depression-associated neurobiological changes including decreased hippocampal brain-derived neurotrophic factor and augmented hypothalamic-pituitary-adrenal responses to stress. Taken together, these findings support a role for decreased brain n-3 PUFAs in the multifactorial etiology of depression, particularly postpartum depression. These findings, and their implications for research and clinical practice, are discussed.

Developmental effects of dietary n-3 fatty acids on activity and response to novelty

Insufficient availability of n-3 polyunsaturated fatty acids (PUFA) during pre- and neonatal development decreases accretion of docosahexaenoic acid (DHA, 22:6n-3) in the developing brain. Low tissue levels of DHA are associated with neurodevelopmental disorders including attention deficit hyperactivity disorder (ADHD). In this study, 1st- and 2nd-litter male Long-Evans rats were raised from conception on a Control diet containing alpha-linolenic acid (4.20 g/kg diet), the dietarily essential fatty acid precursor of DHA, or a diet Deficient in alpha-linolenic acid (0.38 g/kg diet). The Deficient diet resulted in a decrease in brain phospholipid DHA of 48% in 1st-litter pups and 65% in 2nd-litter pups. Activity, habituation, and response to spatial change in a familiar environment were assessed in a single-session behavioral paradigm at postnatal days 28 and 70, inclusive. Activity and habituation varied by age with younger rats exhibiting higher activity, less habituation, and less stimulation of activity induced by spatial novelty. During the first and second exposures to the test chamber, 2nd-litter Deficient pups exhibited higher levels of activity than Control rats or 1st-litter Deficient pups, and less habituation during the first exposure, but were not more active after introduction of a novel spatial stimulus. The higher level of activity in a familiar environment, but not after introduction of a novel stimulus is consistent with clinical observations in ADHD. The observation of this effect only in 2nd-litter rats fed the Deficient diet suggests that brain DHA content, rather than dietary n-3 PUFA content, likely underlies these effects.

Effects of a high fat or a balanced omega 3/omega 6 diet on cytokines levels and DNA damage in experimental colitis

OBJECTIVE

High-fat diets have been shown to be a risk factor for ulcerative colitis (UC). Omega-6 polyunsaturated fatty acids are considered to increase lipid peroxidation, while the omega-3 polyunsaturated fatty acid exerts a chemopreventative effect. We evaluated the effect of high-fat diets (20%) enriched with fish or soybean oil on colonic inflammation and DNA damage in dextran sulfate sodium-induced colitis.

METHODS

Male Wistar rats (28-30 days) were fed an American Institute of Nutrition (AIN)-93 diet for 47 days and divided into five groups: control normal fat non-colitic (C) or control colitis (CC), high soybean fat group (HS) colitis, high fish fat group colitis, or high-fat soybean plus fish oil colitis. UC was induced from day 35 until day 41 by 3% dextran sulfate sodium. On day 47, the rats were anesthetized; blood samples collected for corticosterone determination, and the distal colon was excised to quantify interleukin-4 (IL-4), IL-10, and interferon-gamma levels, myeloperoxidase activity, histological analyses, and DNA damage. The disease activity index was recorded daily.

RESULTS

The disease activity index, histological analysis, myeloperoxidase activity, IL-4, interferon-gamma, and corticosterone levels did not differ among the colitic groups. IL-10 was significantly increased by the high fish fat group diet in relation to HS, but only the high soybean-fish fat diet increased the IL-10/IL-4 ratio (anti-inflammatory/pro-inflammatory) to levels closer to the C group and reduced DNA damage compared to the HS group (P<0.05).

CONCLUSION

The data show that high-fat diets did not exacerbate UC and suggest that the soybean and fish oil mixture, more than the fish oil alone, could be a complementary therapy to achieve a cytokine balance in UC.

Gender differences in rat erythrocyte and brain docosahexaenoic acid composition: role of ovarian hormones and dietary omega-3 fatty acid composition

The two-fold higher prevalence rate of major depression in females may involve vulnerability to omega-3 fatty acid deficiency secondary to a dysregulation in ovarian hormones. However, the role of ovarian hormones in the regulation of brain omega-3 fatty acid composition has not been directly evaluated. Here we determined erythrocyte and regional brain docosahexaenoic acid (DHA, 22:6n-3) composition in intact male and female rats, and in chronically ovariectomized (OVX) rats with or without cyclic estradiol treatment (2 microg/4d). All groups were maintained on diets with or without the DHA precursor alpha-linolenic acid (ALA, 18:3n-3). We report that both male (-21%) and OVX (-19%) rats on ALA+ diet exhibited significantly lower erythrocyte DHA composition relative to female controls. Females on ALA+ diet exhibited lower DHA composition in the prefrontal cortex (PFC) relative males (-5%). OVX rats on ALA+ diet exhibited significantly lower DHA composition in the hippocampus (-6%), but not in the PFC, hypothalamus, or midbrain. Lower erythrocyte and hippocampus DHA composition in OVX rats was not prevented by estrogen replacement. All groups maintained on ALA- diet exhibited significantly lower erythrocyte and regional brain DHA composition relative to groups on ALA+ diet, and these reductions were greater in males but not in OVX rats. These preclinical data corroborate clinical evidence for gender differences in peripheral DHA composition (female>male), demonstrate gender differences in PFC DHA composition (male>female), and support a link between ovarian hormones and erythrocyte and region-specific brain DHA composition.

Ethnic differences in early pregnancy maternal n-3 and n-6 fatty acid concentrations: an explorative analysis

Ethnicity-related differences in maternal n-3 and n-6 fatty acid status may be relevant to ethnic disparities in birth outcomes observed worldwide. The present study explored differences in early pregnancy n-3 and n-6 fatty acid composition of maternal plasma phospholipids between Dutch and ethnic minority pregnant women in Amsterdam, the Netherlands, with a focus on the major functional fatty acids EPA (20 : 5n-3), DHA (22 : 6n-3), dihomo-gamma-linolenic acid (DGLA; 20 : 3n-6) and arachidonic acid (AA; 20 : 4n-6). Data were derived from the Amsterdam Born Children and their Development (ABCD) cohort (inclusion January 2003 to March 2004). Compared with Dutch women (n 2443), Surinamese (n 286), Antillean (n 63), Turkish (n 167) and Moroccan (n 241) women had generally lower proportions of n-3 fatty acids (expressed as percentage of total fatty acids) but higher proportions of n-6 fatty acids (general linear model; P < 0.001). Ghanaian women (n 54) had higher proportions of EPA and DHA, but generally lower proportions of n-6 fatty acids (P < 0.001). Differences were most pronounced in Turkish and Ghanaian women, who, by means of a simple questionnaire, reported the lowest and highest fish consumption respectively. Adjustment for fish intake, however, hardly attenuated the differences in relative EPA, DHA, DGLA and AA concentrations between the various ethnic groups. Given the limitations of this observational study, further research into the ethnicity-related differences in maternal n-3 and n-6 fatty acid patterns is warranted, particularly to elucidate the explanatory role of fatty acid intake v. metabolic differences.