The acute and long-term effects of dietary fatty acids on vascular function in health and disease

Nutrition, Exercise, and Cognitive Rehabilitation for Dementia Prevention

Dementia is one of the most significant global challenges in medical and social care in the 21st century. It affects not only the patients themselves, but also their families, caregivers, and society in general, causing physical, psychological, and socioeconomic effects. As of 2020, there are approximately 6 million people in Japan aged 65 or older with dementia, and this number is expected to increase to around 7 million by 2025, meaning that one out of every five elderly people will have dementia. To prevent the onset and progression of dementia, it is crucial to have a proper understanding of its risks and adopt a healthy lifestyle. Leading an active life from an early stage can also aid in delaying or preventing the onset of dementia. Livingston has identified 12 risks that can lead to dementia, including physical inactivity, smoking, excessive alcohol consumption, air pollution, head injury, social isolation, poor educational history, obesity, hypertension, diabetes, depression, and hearing loss. Modifying one's lifestyle and leading an active life can be crucial in reducing these risks. The Mediterranean diet is gaining attention as a good practice for dementia prevention due to its diversity, richness in omega-3 fatty acids and vitamins. Exercise has been shown to prevent dementia on biological, behavioral, and socio-psychological levels. Repetitive transcranial magnetic stimulation is a non-invasive brain stimulation method that can alter brain plasticity and is being studied for clinical applications as a non-drug therapy for preventing dementia progression.

The effect of astaxanthin and lycopene on the content of fatty acids in the yolks of chicken eggs under different storage regimes

The level of consumers’ satisfaction with the quality of edible chicken eggs is determined, in particular, by the attractive appearance of the yolks and their content of biologically active substances that have functional properties. Such compounds include carotenoids astaxanthin and lycopene, which can be deposited in the yolks, provide their pigmentation, and as powerful antioxidants, affect the stability of the fatty acid composition of lipids during egg storage. The aim This study aimed mine the effect of supplements of oil extracts of astaxanthin (10, 20, and 30 mg/kg of feed) or lycopene (20, 40, and 60 mg/kg of feed) on the Dion of young hens on the fatty acid composition of the yolks during eggs storage in temperature conditions 4 ±0.5 ℃ and 12 ±0.5 ℃ for 30 days. The experiment used 45 High-Line W36 crossbred laying hens at 24 weeks of age. It was found that the storage temperature of eggs (4 ±0.5 ℃ and 12 ±0.5 ℃) equally affected the fatty acid composition of lipids of egg yolks obtained from laying hens fed lycopene supplements in doses of 20, 40, and 60 mg/kg or astaxanthin in doses of 10, 20 and 30 mg/kg of feed for 30 days. Doses of lycopene from 20 to 60 mg/kg or astaxanthin from 10 to 30 mg/kg in the diet of laying hens contributed to a decrease in egg yolks at both storage temperatures of ω6 PUFA particles: Eicosatetraenoic and 6.9, 12-okadekatrienic acids until their complete disappearance. The addition of astaxanthin to the diet of laying hens reduced and stabilized the ratio of ω3/ω6 PUFA in yolks during egg storage to a greater extent than the addition of lycopene. Storage of lycopene or astaxanthin-enriched edible chicken eggs at 4 ±0.5 °C and 12 ±0.5 °C for 30 days can be used to correct the fatty acid profile of yolk lipids.

Glu298Asp (rs1799983) Polymorphism Influences Postprandial Vascular Reactivity and the Insulin Response to Meals of Varying Fat Composition in Postmenopausal Women: Findings from the Randomized, Controlled Dietary Intervention and VAScular function (DIVAS)-2 Study

BACKGROUND

Previous acute studies suggest the Glu298Asp polymorphism (rs1799983) may influence vascular reactivity in response to long-chain n-3 PUFA intake. However, the effects of this genotype on postprandial vascular function after meals rich in SFAs, n-6 PUFAs, and MUFAs are unclear.

OBJECTIVES

This study determined the impact of the Glu298Asp polymorphism on changes in vascular function and cardiometabolic risk biomarkers in response to sequential meals of varying fat composition.

METHODS

In a randomized, double-blind, crossover, acute study, 32 postmenopausal women (mean ± SD age: 58 ± 5 y; BMI: 25.9 ± 4.1 kg/m2) consumed mixed meals (breakfast: 0 min, 50 g fat; lunch: 330 min, 30 g fat) containing SFAs, n-6 PUFAs, or MUFAs on 3 occasions. Blood samples for cardiometabolic disease risk markers and real-time measures of vascular reactivity [including flow-mediated dilatation (FMD; primary outcome)] were collected/performed before and regularly for 480 min after breakfast. Participants were retrospectively genotyped for the Glu298Asp (rs1799983) polymorphism. Data were analyzed using linear mixed models.

RESULTS

For the postprandial %FMD response, a test fat × genotype interaction was observed for the AUC (P = 0.019) but not incremental AUC (IAUC), with the AUC being ∼24% greater after MUFA- than after SFA- and n-6 PUFA-rich meals in the Glu298 homozygotes (P ≤ 0.026). Test fat × genotype interactions were also evident for postprandial insulin (P ≤ 0.005), with the MUFA-rich meals demonstrating significantly higher AUC (12.8%/14.9%), IAUC (14.6%/20.0%), and maximum concentration (20.0%/34.5%) than the SFA- and n-6 PUFA-rich meals, respectively, in Asp298 carriers (P < 0.05). Genotype did not influence other study outcome measures in response to the test fats.

CONCLUSIONS

Our findings suggest the Glu298Asp polymorphism may represent a potential determinant of the inter-individual variability in postprandial responsiveness of %FMD and insulin to acute meal fat composition in postmenopausal women. Further studies are required to confirm these observations.This trial was registered at clinicaltrials.gov as NCT02144454.

Role of cytochrome P450-derived, polyunsaturated fatty acid mediators in diabetes and the metabolic syndrome

Over the last decade, cases of metabolic syndrome and type II diabetes have increased exponentially. Exercise and ω-3 polyunsaturated fatty acid (PUFA)-enriched diets are usually prescribed but no therapy is effectively able to restore the impaired glucose metabolism, hypertension, and atherogenic dyslipidemia encountered by diabetic patients. PUFAs are metabolized by different enzymes into bioactive metabolites with anti- or pro-inflammatory activity. One important class of PUFA metabolizing enzymes are the cytochrome P450 (CYP) enzymes that can generate a series of bioactive products, many of which have been attributed protective/anti-inflammatory and insulin-sensitizing effects in animal models. PUFA epoxides are, however, further metabolized by the soluble epoxide hydrolase (sEH) to fatty acid diols. The biological actions of the latter are less well understood but while low concentrations may be biologically important, higher concentrations of diols derived from linoleic acid and docosahexaenoic acid have been linked with inflammation. One potential application for sEH inhibitors is in the treatment of diabetic retinopathy where sEH expression and activity is elevated as are levels of a diol of docosahexaenoic acid that can induce the destabilization of the retina vasculature.

Eight weeks of fish oil supplementation does not prevent sitting-induced leg endothelial dysfunction

Prolonged sitting impairs leg endothelial function and this impairment is thought to be mediated by a sustained reduction in blood flow-induced shear stress. However, whether nutritional strategies can be used to prevent sitting-induced leg endothelial dysfunction remains unknown. Herein, we tested the hypothesis that 8 weeks of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation would prevent endothelial dysfunction associated with sitting. Nineteen healthy men were randomly assigned to a placebo group or EPA+DHA group in a double-blind fashion. The EPA+DHA group was administered EPA-rich fish oil, containing 600 mg EPA and 260 mg DHA per day for 8 weeks. The placebo group received matching capsules for the same duration of time. Popliteal artery flow-mediated dilation (FMD) was measured at baseline and before and after a 3-h sitting period. During sitting, blood pressure, popliteal artery diameter, and blood velocity were measured every hour. Throughout the sitting period, popliteal artery blood flow and shear rate were markedly and similarly reduced in both groups (P < 0.05). However, counter to the hypothesis, 3 h of sitting impaired popliteal artery FMD to the same extent in both groups (P < 0.05). In conclusion, daily EPA and DHA supplementation is not effective at preventing the detrimental effects of prolonged sitting on leg endothelial function. Novelty We provide evidence that sitting-induced leg endothelial dysfunction in young healthy subjects cannot be remediated by a nutritional strategy known to produce cardiovascular benefits. This could be partially due to the low total dose of EPA and DHA administered.

Substances of Interest That Support Glaucoma Therapy

Glaucoma is a multifactorial disease in which pro-apoptotic signals are directed to retinal ganglion cells. During this disease the conventional outflow pathway becomes malfunctioning. Aqueous humour builds up in the anterior chamber, leading to increased intraocular pressure. Both of these events are related to functional impairment. The knowledge of molecular mechanisms allows us to better understand the usefulness of substances that can support anti-glaucoma therapy. The goal of glaucoma therapy is not simply to lower intraocular pressure; it should also be to facilitate the survival of retinal ganglion cells, as these constitute the real target tissue in this disease, in which the visual pathway is progressively compromised. Indeed, an endothelial dysfunction syndrome affecting the endothelial cells of the trabecular meshwork occurs in both normal-tension glaucoma and high-tension glaucoma. Some substances, such as polyunsaturated fatty acids, can counteract the damage due to the molecular mechanisms - whether ischemic, oxidative, inflammatory or other - that underlie the pathogenesis of glaucoma. In this review, we consider some molecules, such as polyphenols, that can contribute, not only theoretically, to neuroprotection but which are also able to counteract the metabolic pathways that lead to glaucomatous damage. Ginkgo biloba extract, for instance, improves the blood supply to peripheral districts, including the optic nerve and retina and exerts a neuro-protective action by inhibiting apoptosis. Polyunsaturated fatty acids can protect the endothelium and polyphenols exert an anti-inflammatory action through the down-regulation of cytokines such as TNF-α and IL-6. All these substances can aid anti-glaucoma therapy by providing metabolic support for the cells involved in glaucomatous injury. Indeed, it is known that the food we eat is able to change our gene expression.

One-year daily consumption of buttermilk drink containing lutein-enriched egg-yolks does not affect endothelial function in fasting and postprandial state

Previous results have shown that one-year daily consumption of a lutein-enriched egg yolk containing dairy drink did not significantly affect fasting serum lipid and lipoprotein concentrations in adults with early signs of macular degeneration. The current study further substantiates these findings with parameters reflecting endothelial function. Additionally, we extend our observations from the fasting to the postprandial situation. Subjects participated in a 1-y randomized placebo-controlled dietary intervention trial. 52 subjects were included in the active (Egg) group and 49 in the control (Con) group. Changes in postprandial biochemistry (triacylglycerol (TAG), glucose and non-esterified fatty acids (NEFA)) following a mixed meal and flow-mediated dilation (FMD) analyses were evaluated at the start and after one year intervention. Postprandial glycemic and lipemic responses before the intervention as well as the differences in postprandial responses after one-year intervention were comparable between the Egg and the Con group. Fasting FMD was comparable between the groups before the intervention started and at the end of intervention. Additionally, the change in FMD following a mixed meal was comparable between the groups. To conclude, one-year consumption of a lutein-enriched egg yolk incorporated in a dairy drink has no effect on postprandial lipid and glucose metabolism or endothelial function.

Postprandial lymphatic pump function after a high-fat meal: a characterization of contractility, flow, and viscosity

Dietary lipids are transported from the intestine through contractile lymphatics. Chronic lipid loads can adversely affect lymphatic function. However, the acute lymphatic pump response in the mesentery to a postprandial lipid meal has gone unexplored. In this study, we used the rat mesenteric collecting vessel as an in vivo model to quantify the effect of lipoproteins on vessel function. Lipid load was continuously monitored by using the intensity of a fluorescent fatty-acid analog, which we infused along with a fat emulsion through a duodenal cannula. The vessel contractility was simultaneously quantified. We demonstrated for the first time that collecting lymphatic vessels respond to an acute lipid load by reducing pump function. High lipid levels decreased contraction frequency and amplitude. We also showed a strong tonic response through a reduction in the end-diastolic and systolic diameters. We further characterized the changes in flow rate and viscosity and showed that both increase postprandially. In addition, shear-mediated Ca(2+) signaling in lymphatic endothelial cells differed when cultured with lipoproteins. Together these results show that the in vivo response could be both shear and lipid mediated and provide the first evidence that high postprandial lipid has an immediate negative effect on lymphatic function even in the acute setting.

From sodium intake restriction to nitrate supplementation: Different measures with converging mechanistic pathways?

Endothelial nitric oxide synthase is at the centre of endothelial physiology producing nitric oxide which dilates blood vessels, inhibits platelet aggregation and smooth muscle cell proliferation and reduces adhesion molecule production. The laminar shear stress is a common test used usually as the flow mediated dilatation test (FMD) which is sensitive to saturated fat, sodium and potassium although with the latter ion it is possible potassium has direct effects on ion channels in the smooth muscle cell as well as the endothelial cell. High blood pressure and blood cholesterol both reduce nitric oxide production, the latter probably by increasing caveolin-1 which binds nitric oxide synthase. Saturated fat reduces nitric oxide by elevating LDL cholesterol and caveolin-1 while insulin stimulates nitric oxide synthase activity by serine phosphorylation. Polyphenols from tea, coffee and cocoa and virgin olive oil enhance FMD and eNOS activity is essential for this activity. Wine polyphenols produce mixed results and it is not clear at present that they are beneficial. Blackberries and other polyphenol-rich fruit also enhance FMD. Dietary nitrate from beetroot and green leafy vegetables is converted to nitrite by salivary microbes and then to nitric oxide and this acts directly on the smooth muscle to lower blood pressure particularly in a low oxygen environment. Dietary nitrate also improves work efficiency and improves flow mediated dilatation.

A review of recent evidence in human studies of n-3 and n-6 PUFA intake on cardiovascular disease, cancer, and depressive disorders: does the ratio really matter?

Polyunsaturated fatty acids (PUFAs) have been considered of great interest for human health due to their potential anti-inflammatory action that may protect from a number of chronic-degenerative diseases with an inflammatory pathogenesis. This review aimed to report the most updated evidence of both n-3 and n-6 PUFAs effect on cardiovascular disease, cancer, and depression in humans. Attention has been also paid to those studies exploring the effects of the ratio intake. Results from pooled analyses of human studies reported a general positive effect of n-3 PUFAs intake on all outcomes considered. In contrast, the role of n-6 PUFAs on human health needs to be better assessed in order to clearly identify which compound exerts beneficial/harmful effects. Only a limited number of clinical studies considered the n-3:n-6 PUFAs ratio, rather reporting contrasting results. A number of limitations when considering the ratio between these two families of PUFAs have risen.

Whatever happened to the epoxyeicosatrienoic Acid-like endothelium-derived hyperpolarizing factor? The identification of novel classes of lipid mediators and their role in vascular homeostasis

SIGNIFICANCE

Cytochrome P450 (CYP) epoxygenases metabolize arachidonic acid (AA) to generate epoxyeicosatrienoic acids (EETs). The latter are biologically active and reported to act as an endothelium-derived hyperpolarizing factor as well as to affect angiogenic and inflammatory signaling pathways.

RECENT ADVANCES

In addition to AA, the CYP enzymes also metabolize the ω-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid and docosahexaenoic acid to generate bioactive lipid epoxide mediators. The latter can be more potent than the EETs, but their actions are under investigated. The ω3-epoxides, like the EETs, are metabolized by the soluble epoxide hydrolase (sEH) to corresponding diols, and epoxide hydrolase inhibition increases epoxide levels and demonstrates anti-hypertensive as well as anti-inflammatory effects.

CRITICAL ISSUES

It seems that the overall consequences of CYP activation largely depend on enzyme substrate preference and the endogenous ω-3/ω-6 PUFA ratio.

FUTURE DIRECTIONS

More studies combining PUFA profiling with cell signaling and disease studies are required to determine the spectrum of molecular pathways affected by the different ω-6 and ω-3 PUFA epoxides and diols. Such information may help improve dietary studies aimed at promoting health via ω-3 PUFA supplementation and/or sEH inhibition.

Effect of storage and cooking on the fatty acid profile of omega-3 enriched eggs and pork meat marketed in Belgium

The fatty acids (FA) profile was determined in n-3 enriched (Columbus™) Belgian eggs and pork in order to evaluate to what extent the n-3 fatty acids, which are very sensitive to oxidation, are resistant to storage or cooking. In standard eggs or pork, no change of the fatty acid profile was observed after storage or cooking without culinary fat, as well as in Columbus™ eggs and pork after storage. Some cooking processes (eggs in custard and meat in oven) induced a slight significant loss of n-3 fatty acids in Columbus™ eggs or pork (11.1% in fat from eggs cooked in custard vs. 15.3% in raw Columbus™ eggs and 11.0% in fat from oven cooked meat vs. 11.6% in raw Columbus™ meat). As expected, when Columbus™ pork is cooked with culinary fat, its fatty acid profile is modified according to the nature of the fat used.

The pharmacology of the cytochrome P450 epoxygenase/soluble epoxide hydrolase axis in the vasculature and cardiovascular disease

Over the last 20 years, it has become clear that cytochrome P450 (P450) enzymes generate a spectrum of bioactive lipid mediators from endogenous substrates. However, studies focused on the determining biologic activity of the P450 system have focused largely on the metabolites generated by one substrate (i.e., arachidonic acid). However, epoxides and diols derived from other endogenous substrates, such as linoleic acid, eicosapentaenoic acid, and docosahexaenoic acid, may be generated in higher concentrations and may potentially be of more physiologic relevance. Recent studies that used a combination of phenotyping and lipid array analyses revealed that rather than being inactive products, fatty acid diols play important roles in a number of biologic processes including inflammation, angiogenesis, and metabolic regulation. Moreover, inhibitors of the soluble epoxide hydrolase that increase epoxide but decrease diol levels have potential for the treatment of the metabolic syndrome.

A review of the biologic and pharmacologic role of docosapentaenoic acid n-3

Fish oil contains a complex mixture of omega-3 fatty acids, of which eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) are the three predominant forms. There has been a plethora of previous research on the effects and associations of fish oil supplementation with various clinical manifestations. While the majority of this work was focused on EPA and DHA as the active compounds, emerging research has begun to elucidate the specific role that DPA plays in these physiological processes and its differences with the other omega-3 fatty acids. The purpose of this review is to focus on the new studies undertaken with DPA. This review summarizes the biochemical mechanisms involved in the biosynthesis and metabolism of DPA before focusing on its effects in cardiovascular disease, immune function, and psychiatric and cognitive health. The limited studies point toward a positive role that DPA supplementation can play in these processes and that is separate and distinct from traditional supplementation with DHA and EPA.

A review of the biologic and pharmacologic role of docosapentaenoic acid n-3

Fish oil contains a complex mixture of omega-3 fatty acids, of which eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) are the three predominant forms. There has been a plethora of previous research on the effects and associations of fish oil supplementation with various clinical manifestations. While the majority of this work was focused on EPA and DHA as the active compounds, emerging research has begun to elucidate the specific role that DPA plays in these physiological processes and its differences with the other omega-3 fatty acids. The purpose of this review is to focus on the new studies undertaken with DPA. This review summarizes the biochemical mechanisms involved in the biosynthesis and metabolism of DPA before focusing on its effects in cardiovascular disease, immune function, and psychiatric and cognitive health. The limited studies point toward a positive role that DPA supplementation can play in these processes and that is separate and distinct from traditional supplementation with DHA and EPA.