Percentage oleic acid is inversely related to percentage arachidonic acid in total lipids of rat serum

Parental dietary arachidonic acid altered serum fatty acid profile, hepatic antioxidant capacity, and lipid metabolism in domestic pigeons (Columba livia)

The aim of this study was to explore the effects of dietary arachidonic acid on serum fatty acid profile, hepatic antioxidant capacity, and lipid metabolism in pigeon squabs by supplementing arachidonic acid in their parental diets. A completely randomized design was conducted consisting of control group, 0.05% dietary arachidonic acid supplementation group, 0.1% dietary arachidonic acid supplementation group, and 0.2% dietary arachidonic acid supplementation group. Six randomly selected squabs from each group were sampled on Day 21 post-hatch. Results indicated that moderate level (0.05%) of arachidonic acid in parental diets for pigeon squabs improved lipid metabolism via regulation on serum lipid profile and fatty acid composition and tended to reduce hepatic lipid accumulation in the premise of negligible damage to antioxidant status. Unfortunately, excessive parental supplementation of dietary arachidonic acid might be harmful to squab health. The regulatory effects of arachidonic acid were sensitive to the arachidonic acid doses. In conclusion, parental dietary arachidonic acid at 0.05% could be beneficial for squabs to maintain health as reflective aspects in ameliorative serum lipid profile, fatty acid composition, and reduced hepatic lipid accumulation.

Intended Ranges and Correlations between Percentages of Variables Like Oleic Acid, Eicosapentaenoic Acid, and Arachidonic Acid

In chicken muscle, we previously showed that ranges of oleic acid (OA), arachidonic acid (AA), and eicosapentaenoic acid (EPA) might explain why %OA was inversely related to %AA, and that %EPA correlated positively with %AA. We here try to clarify further how ranges of the fatty acids could make strong associations between their relative amounts, utilizing published data from chicken muscle and human sera. We generated random number variables (OA’, AA’, EPA’) in lieu of the true variables, and we studied effects of altering their ranges upon scatterplots of %OA’ vs. %AA’ (%EPA’), and %AA’ vs. %EPA’. To explain the results, we first applied the equation OA’ + AA’ + EPA’ = S, i.e., %OA’ + %AA’ + %EPA’ = 100. Next, we considered how the OA’ (AA’, EPA’) fractions of S related to S. Increasing the OA’ range towards higher values improved the positive association between %AA’ and %EPA’. Thus, increased intake of OA could improve the positive correlations between percentages of eicosanoid precursors, raising the question of whether “intended ranges” of some fatty acids represent a case of evolutionary selection to, e.g., achieve balance between eicosanoids.

Study of HSA interactions with arachidonic acid using spectroscopic methods revealing molecular dynamics of HSA-AA interactions

The interaction between human serum albumin (HSA) and arachidonic acid (AA) as an unsaturated fatty acid were investigated in the present study using methods including UV-VIS spectrophotometry, fluorescence and circular dichroism (CD) spectroscopy, lifetime measurements, fluorescence anisotropy measurements and visual molecular dynamics (MD). The thermodynamic parameters were assessed from HSA thermal and chemical denaturation in the presence and absence of AA. From the thermal denaturation, the Tm and ΔG˚(298K) magnitudes obtained were 327.7 K and 88 kJ/mol, respectively, for HSA alone, and 323.4 K and 85 kJ/mol, respectively, following treatment with a 10 µM AA concentration. The same manner of reduction in Gibbs free energy as a criterion of protein stability was achieved during chemical denaturation by urea in the presence of AA. The present study investigates HSA binding nature through MD approaches, and the results indicated that the binding affinity of AA to the subdomain IIA of HSA is greater compared with that of subdomain IIIA. Although the HSA regular secondary structure evaluation by CD exhibited a minor change following incubation with AA, its tertiary structure revealed an observable fluctuation. Thus, it appears that the interaction between AA and HSA requires minor instability and partial structural changes.

Induced Ketosis as a Treatment for Neuroprogressive Disorders: Food for Thought?

Induced ketosis (or ketone body ingestion) can ameliorate several changes associated with neuroprogressive disorders, including schizophrenia, bipolar disorder, and major depressive disorder. Thus, the effects of glucose hypometabolism can be bypassed through the entry of beta-hydroxybutyrate, providing an alternative source of energy to glucose. The weight of evidence suggests that induced ketosis reduces levels of oxidative stress, mitochondrial dysfunction, and inflammation-core features of the above disorders. There are also data to suggest that induced ketosis may be able to target other molecules and signaling pathways whose levels and/or activity are also known to be abnormal in at least some patients suffering from these illnesses such as peroxisome proliferator-activated receptors, increased activity of the Kelch-like ECH-associated protein/nuclear factor erythroid 2-related factor 2, Sirtuin-1 nuclear factor-κB p65, and nicotinamide adenine dinucleotide (NAD). This review explains the mechanisms by which induced ketosis might reduce mitochondrial dysfunction, inflammation, and oxidative stress in neuropsychiatric disorders and ameliorate abnormal levels of molecules and signaling pathways that also appear to contribute to the pathophysiology of these illnesses. This review also examines safety data relating to induced ketosis over the long term and discusses the design of future studies.

Olive oil promotes wound healing of mice pressure injuries through NOS-2 and Nrf2

The pressure injury environment is characterized by overproduction of reactive oxygen species and exacerbated inflammation, which impair the healing of these lesions. Mediterranean-like diet may be a good intervention to improve the healing of pressure injury owing to its anti-inflammatory and antioxidant components. Thus, this study evaluated the hypothesis that olive oil, as a main source of lipid in Mediterranean diet, could improve cutaneous wound healing of pressure injury in mice. Male Swiss mice were randomly divided into standard, olive oil, or soybean oil plus olive oil groups and fat represented 10% of total calories in all groups. Four weeks after the beginning of diet administration, 2 cycles of ischemia-reperfusion (IR) by external application of 2 magnets disks were performed in the dorsal skin to induce pressure injury formation. Fourteen days after the end of the second IR cycle, olive oil-based diet reduced neutrophils cells and cyclooxygenase-2 protein expression and increased nitric oxide synthase-2 and protein and lipid oxidation. Olive oil based-diet also increased nuclear factor erythroid 2-related factor 2 protein expression and collagen type I precursor protein expression. In addition, administration of olive oil-based diet promoted wound closure at 7, 10, and 14 days after the end of the second IR cycle. These findings support the hypothesis that olive oil-based diet improves cutaneous wound healing of pressure injury in mice through the reduction of inflammation and stimulation of redox equilibrium.

The inverse association between relative abundances of oleic acid and arachidonic acid: a case of distribution dependent regulation?

BACKGROUND

Since oleic acid (OA, 18:1 c9) and arachidonic acid (AA, 20:4 n6) may have antagonistic actions, it is of interest to assess their relative abundances. We previously reported an inverse correlation between % OA and %AA. However, percentages of the same sum may be correlated without involving biology. We now investigate whether random numbers, generated within the true concentration distributions for OA and AA, may be correlated.

METHODS

We reanalysed data from a previous diet trial in chickens. Breast muscle was collected, and the concentration of fatty acids in muscle lipids was determined using gas chromatography. We computed R = S - OA - AA, where S is the sum of all fatty acids (g/kg) and R is concentration of all fatty acids, except OA and AA. From histograms we found physiological distributions of OA, AA and R. Then we generated random numbers for each of 3 variables (n = 163), within the distributions (g/kg) for OA (1-7), AA (0.25-0.39), and R (4-10). Next we made scatterplots of % OA vs. % AA, and studied how a narrowing or broadening of distributions might change the relationship.

RESULTS

Also with random numbers, generated within true concentration distributions for OA and AA, we found an inverse relationship between their percentages (r = - 0.356, p < 0.001; r = 163); however, the points were not close to the regression line. The %OA vs. %AA relationship changed appreciably in response to slightly altering concentration distributions of OA and AA, and a negative association could be changed to become positive.

CONCLUSION

Using random numbers, generated within the biological distributions for OA, AA, and sum of the remaining fatty acids, we found an inverse relationship between "% OA" and "% AA", but the scatterplot was poor compared with that obtained with real values. The association between relative abundances of random numbers of OA and AA was very sensitive to changes in distributions, and a negative association could be changed to become positive by slightly altering the distributions. Thus, the association between relative abundances of OA and AA could be partly caused by the particular distribution of the fatty acid concentration: a Distribution Dependent Correlation.

Vitamin D deficiency influences fatty acid metabolism

Reports indicate that maternal vitamin D deficiency may be associated with increased inflammation. Long chain polyunsaturated fatty acids (LCPUFAs); omega-3 and omega-6 fatty acids are known to have anti-inflammatory and pro-inflammatory properties respectively. The present study examines the effect of vitamin D deficiency on fatty acid composition and metabolism in a rat model. Female Wistar rats were randomly divided into two groups (n = 8/group) as follows; control and vitamin D deficient (VDD). Diets (control: 1000 IU D3/kg diet; VDD: 0 IU D3/kg diet) were given from weaning and continued throughout pregnancy. Pregnant female rats were dissected on gestational day 20 to collect blood, liver and placenta. The VDD diet reduced maternal serum 25-hydroxyviatmin D3 levels (p < 0.001) as compared to control. Maternal vitamin D deficiency resulted in lower total weight gain and placental weight (p < 0.05 for both) during pregnancy. Animals from VDD group demonstrated higher arachidonic acid (AA) levels in both the liver and plasma (p < 0.05 for both) as compared to control. Liver, plasma and placental monounsaturated fatty acid levels (MUFA) were lower (p < 0.01 for all) while plasma total saturated fatty acids (SFA) (p = 0.05) were higher in the VDD group. Animals from the VDD group demonstrated lower ∆9-desaturase activity index (p < 0.01 for all) in the liver, plasma and placenta. The plasma ∆5-desaturase activity index (p < 0.05) was higher although no change was observed in the ∆6-desaturase activity index. However, the mRNA levels of liver ∆6-desaturase was lower (p < 0.05) in the VDD group. Our findings indicate that maternal vitamin D deficiency influences fatty acid desaturase activity and expression and therefore alters maternal fatty acid metabolism.

Moderate levels of dietary arachidonic acid reduced lipid accumulation and tended to inhibit cell cycle progression in the liver of Japanese seabass Lateolabrax japonicus

To investigate the physiological roles of dietary arachidonic acid (ARA) in fish, a feeding trial with Japanese seabass was conducted, followed by a hepatic transcriptome assay. Six experimental diets differing basically in ARA level (0.05%, 0.22%, 0.37%, 0.60%, 1.38% and 2.32% of dry matter) were used in the feeding trial. Liver samples from fish fed diets with 0.05% and 0.37% ARA were subjected to transcriptomic assay, generating a total of 139 differently expressed unigenes, which were primarily enriched in lipid metabolism and cell cycle-related signaling pathways. Then, qRT-PCR validation on lipid metabolism and cell cycle-related genes as well as corresponding enzyme-linked immunosorbent assay of selected proteins were conducted with liver samples from all six groups. Moderated ARA levels reduced lipogenesis and stimulated β-oxidation concurrently, but high ARA levels seemed to affect lipid metabolism in complicated ways. Both gene expression and protein concentration of cell cycle-related proteins were decreased by moderate levels of dietary ARA. The lipid content and fatty acid composition in fish confirmed the transcription and protein concentration results related to lipid metabolism. In conclusion, moderate levels of dietary ARA (0.37% and 0.60%) reduced lipid accumulation and tended to inhibit cell cycle progression in the liver of Japanese seabass.

Participation of Arachidonic Acid Metabolism in the Aortic Aneurysm Formation in Patients with Marfan Syndrome

Marfan syndrome (MFS) is a pleiotropic genetic disease involving the cardiovascular system where a fibrillin-1 mutation is present. This mutation is associated with accelerated activation of transforming growth factor β (TGFβ1) which contributes to the formation of aneurysms in the root of the aorta. There is an imbalance in the synthesis of thromboxane A₂ (TXA₂) and prostacyclin, that is a consequence of a differential protein expression of the isoforms of cyclooxygenases (COXs), suggesting an alteration of arachidonic acid (AA) metabolism. The aim of this study was to analyze the participation of AA metabolism associated with inflammatory factors in the dilation and dissection of the aortic aneurysm in patients with MFS. A decrease in AA (p = 0.02), an increase in oleic acid (OA), TGFβ1, tumor necrosis factor alpha (TNFα), prostaglandin E₂ (PGE₂) (p < 0.05), and COXs activity (p = 0.002) was found. The expressions of phospholipase A₂ (PLA₂), cytochrome P450 (CYP450 4A), 5-lipoxygenase (5-LOX), COX2 and TXA2R (p < 0.05) showed a significant increase in the aortic aneurysm of patients with MFS compared to control subjects. COX1, 6-keto-prostaglandin 1 alpha (6-keto-PG_1α) and 8-isoprostane did not show significant changes. Histological examination of the aortas showed an increase of cystic necrosis, elastic fibers and collagen in MFS. The results suggest that there are inflammatory factors coupled to genetic factors that predispose to aortic endothelial dysfunction in the aortic tissue of patients with MFS. There is a decrease in the percentage of AA, associated with an increase of PLA₂, COX2/TXA2R, CYP450 4A, and 5-LOX which leads to a greater synthesis of PGE₂ than of 6-keto-PGF_1α, thus contributing to the formation of the aortic aneurysm. The evident loss of the homeostasis in these mechanisms confirms that there is a participation of the AA pathway in the aneurysm progression in MFS.

Contractile function recovery in severely injured gastrocnemius muscle of rats treated with either oleic or linoleic acid

NEW FINDINGS

What is the central question of this study? Oleic and linoleic acids modulate fibroblast proliferation and myogenic differentiation in vitro. However, their in vivo effects on muscle regeneration have not yet been examined. We investigated the effects of either oleic or linoleic acid on a well-established model of muscle regeneration after severe laceration. What is the main finding and its importance? We found that linoleic acid increases fibrous tissue deposition and impairs muscle regeneration and recovery of contractile function, whereas oleic acid has the opposite effects in severely injured gastrocnemius muscle, suggesting that linoleic acid has a harmful effect and oleic acid a potential therapeutic effect on muscle regeneration. Oleic and linoleic acids control fibroblast proliferation and myogenic differentiation in vitro; however, there was no study in skeletal muscle in vivo. The aim of this study was to evaluate the effects of either oleic or linoleic acid on the fibrous tissue content (collagen deposition) of muscle and recovery of contractile function in rat gastrocnemius muscle after being severely injured by laceration. Rats were supplemented with either oleic or linoleic acid for 4 weeks after laceration [0.44 g (kg body weight)^-1 day^-1 ]. Muscle injury led to an increase in oleic-to-stearic acid and palmitoleic-to-palmitic acid ratios, suggesting an increase in Δ⁹ desaturase activity. Increased fibrous tissue deposition and reduced isotonic and tetanic specific forces and resistance to fatigue were observed in the injured muscle. Supplementation with linoleic acid increased the content of eicosadienoic (20:2, n-6) and arachidonic (20:4, n-6) acids, reduced muscle mass and fibre cross-sectional areas, increased fibrous tissue deposition and further reduced the isotonic and tetanic specific forces and resistance to fatigue induced by laceration. Supplementation with oleic acid increased the content of docosahexaenoic acid (22:6, n-3) and abolished the increase in fibrous tissue area and the decrease in isotonic and tetanic specific forces and resistance to fatigue induced by muscle injury. We concluded that supplementation with linoleic acid impairs muscle regeneration and increases fibrous tissue deposition, resulting in impaired recovery of contractile function. Oleic acid supplementation reduced fibrous tissue deposition and improved recovery of contractile function, attenuating the tissue damage caused by muscle injury.

Influence of cafeteria diet and fish oil in pregnancy and lactation on pups' body weight and fatty acid profiles in rats

PURPOSE

The aim was to determine the effects of cafeteria diet (CD) and fish oil supplements given to pregnant and lactating rats on the birth weight and fatty acid profiles of their offspring.

METHODS

Female rats were given standard diet (STD) or CD for 22 days before pregnancy. After mating, some animals remained on STD or CD; for some CD rats, the diet was supplemented with 8.78 % fish oil (CD-FO). After 12 days, half the CD-FO group returned to CD (CD-FO12) and the others remained on CD-FO.

RESULTS

At birth, body weights of pups of the three CD groups were lower than STD, maintained until 21 days in the CD-FO group only. At the end of lactation, dams of the CD groups had increased plasma triacylglycerols (TAG), non-esterified fatty acids, and glycerol concentrations, whereas most n-6 long-chain polyunsaturated fatty acids (LCPUFA) were decreased, the effect being greatest in the CD-FO group, where most n-3 LCPUFA were increased and indices of Δ(5) and Δ(6) desaturase activities decreased. The 21-day-old pups of the CD group had increased plasma TAG, not present in the CD-FO group, which had increased 3-hydroxybutyrate concentrations. In both 2- and 21-day-old CD pups, plasma concentrations of ARA were lower than STD, and even lower in the two CD-FO groups.

CONCLUSIONS

The effect of CD and CD-FO decreasing pups body weight could be related to decreased concentrations of ARA, caused by the inhibition of the Δ(5) and Δ(6) desaturases in the pathway of n-6 LCPUFA biosynthesis.

Variation of unsaturated fatty acids in soybean sprout of high oleic acid accessions

Oleic acid and oleic acid rich foods may have beneficial health effects in humans. Soybeans with high oleic acid (around 80% in seed oil) have been developed. Soybean sprouts are an important vegetable in Korea, Japan and China. The objective of this study was to investigate the variation of unsaturated fatty acids, oleic, linoleic and α-linolenic acids, in sprouts from soybeans with normal and high oleic acid concentration. Twelve soybean accessions with six high oleic acid lines, three parents of high oleic acid lines, and three checks with normal and high oleic acid concentration were used in this study. The unsaturated fatty acid concentration in sprouts from each genotype was similar to the concentration in the ungerminated seed. The oleic acid concentration in the sprouts of high oleic acid lines (up to 80%) was still high (>70%) compared to the ungerminated seed. Thus, high oleic soybean varieties developed for sprout production could add valuable health benefits to sprouts and the individuals who consume this vegetable.

The inverse association between relative abundances of oleic acid and arachidonic acid is related to alpha -linolenic acid

Background

Many health effects of oils rich in oleic acid (OA, 18:1 n9) seem to be opposite those of arachidonic acid (AA, 20:4 n6), i.e. concerning cardiovascular risk. In recent studies in humans and in the rat we observed that percentages of OA and AA were inversely related, raising the question of whether the inverse association is a general one, and how it might be explained. In the present work we examine whether percentages of OA and AA are inversely associated in breast muscle lipids of chickens, and whether alpha-linolenic acid (ALA) may be related to the OA/AA ratio.

Methods

The study group consisted of 163 chickens. Breast muscle was collected, and the concentration of fatty acids in muscle lipids was determined using gas chromatography. We studied association between fatty acids using bivariate correlations (Pearson) and linear regression. Synthesis of OA from stearic acid (Stear) was estimated using the OA/Stear ratio, and formation of AA from linoleic acid (LA) was estimated by the AA/LA ratio.

Results

We found a strong inverse relationship (r = -0.942, p < 0.001; n = 163) between % OA and % AA in breast muscle lipids of the chickens. There was an inverse association (r = -0.887, p < 0.001) between the OA/Stearic acid ratio, estimating Delta9 desaturase, and the AA/LA ratio, estimating desaturases/elongase activities. Furthermore, there was a strong negative association between % AA and the OA/Stearic acid ratio (r = -0.925, p < 0.001), and % OA correlated negatively (r = -0.914, p < 0.001) with the AA/LA ratio. ALA was positively associated (r = 0.956, p < 0.001) with the OA/AA ratio, and this association prevailed when controlling for the other fatty acids. ALA was positively associated (r = 0.857, p < 0.001) with the OA/Stear ratio, but was negatively related (r = -0.827, p < 0.001) to the AA/LA ratio.

Conclusions

The relative abundances of OA and AA that are inversely related in muscle lipids of chickens may be explained by a feedback regulation between the synthesis of OA and AA, and related to ALA, which seems to stimulate formation of OA, and inhibit synthesis of AA, but further studies are required to clarify whether this hypothesis is valid.

Percentages of oleic acid and arachidonic acid are inversely related in phospholipids of human sera

Background

Many health effects of oils rich in oleic acid (18:1 n9) seem to be opposite those of arachidonic acid (20:4 n6), i.e. concerning cardiovascular risk. In recent study in rats we observed that percentages of oleic acid and arachidonic acid were inversely related in total serum lipids. In the present work we investigate whether an inverse relationship between this couple of fatty acids also exists in the phospholipid fraction of human sera.

Methods

The study group consisted of 11 men and 35 women. Mean age was 23.8 ± 2.5 years (mean ± SD), and the body mass index was 23.5 ± 3.2 kg/m². After fasting overnight, blood was drawn and the concentration of fatty acids in serum phospholipids was determined, using gas chromatography. We studied the association between percentages of oleic acid and arachidonic acid using bivariate correlations (Pearson), and multiple linear regressions.

Results

We found an inverse relationship (r = −0.563, p < 0.001; n = 46) between % oleic acid and % arachidonic acid in the serum phosholipid fraction of the 46 fasting subjects. By multiple linear regression, and % 20:4 n6 as the dependent variable, the inverse association with % 18:1 n9 persisted when controlling for sex, age, body mass index, and percentages of the other fatty acids measured (t = −17.6, p < 0.001). Per cent 20:4 n6 seemed to correlate negatively (r = −0.289, p = 0.05) with the (18:1 n9)/(18:0) ratio, estimating Delta9 desaturase activity, and % oleic acid correlated negatively (r = −0.321, p = 0.029) with the (20:4)/(18:2) ratio, estimating desaturases/elongase activities.

Conclusions

In a group of healthy human subjects, percentages of oleic acid and arachidonic acid were inversely related, and the inverse association persisted when controlling for possible confounding variables. The findings might contribute to explain positive health effects of foods rich in oleic acid.