Omega 3 Polyunsaturated Fatty Acids Improve Endothelial Dysfunction in Chronic Renal Failure: Role of eNOS Activation and of Oxidative Stress

The Combined Effects of the Most Important Dietary Patterns on the Incidence and Prevalence of Chronic Renal Failure: Results from the US National Health and Nutrition Examination Survey and Mendelian Analyses

BACKGROUND

We aimed to comprehensively assess the relationship of specific dietary patterns and various nutrients with chronic kidney disease (CKD) and its progression.

METHODS

The observational study data were from the NHANES 2005-2020. We calculated four dietary pattern scores (healthy eating index 2020 (HEI-2020), dietary inflammatory index (DII), alternative mediterranean diet (aMed), and dietary approaches to stop hypertension (DASH)) and the intakes of various nutrients and defined CKD, CKD-very high risk, and kidney dialysis. Associations between dietary patterns and nutrients and disease were assessed by means of two logistic regression models. Two-sample MR was performed with various food and nutrients as the exposure and CKD, kidney dialysis as the outcome. Sensitivity analyses were conducted to verify the reliability of the results.

RESULTS

A total of 25,167 participants were included in the analyses, of whom 4161 had CKD. HEI-2020, aMed, and DASH were significantly negatively associated with CKD and CKD-very high risk at higher quartiles, while DII was significantly positively associated. A higher intake of vitamins and minerals may reduce the incidence and progression of CKD to varying degrees. The MR results, corrected for false discovery rates, showed that a higher sodium intake was associated with a higher prevalence of CKD (OR: 3.91, 95%CI: 2.55, 5.99).

CONCLUSIONS

Adhering to the three dietary patterns of HEI-2020, aMed, and DASH and supplementing with vitamins and minerals benefits kidney health.

Natural supplements in antiphospholipid syndrome: A case for further study

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by thrombotic events and/or pregnancy complications in the presence of persistently positive antiphospholipid antibodies (aPL). Although long-term anticoagulation with vitamin K antagonists is considered standard of care, there is an unmet need for safe therapeutics as primary thromboprophylaxis or adjuncts to standard of care in APS. APS is driven by oxidative stress, procoagulant, proinflammatory and angiogenic pathways. For these reasons there has been an increased interest into the investigation of antithrombotic, anti-inflammatory and anti-oxidant properties of natural supplements in APS. The objective of this review is to summarize the mechanistic, epidemiologic and clinical evidence behind the use of natural supplements in APS, with a specific focus on vitamin D, omega-3 fatty acids, coenzyme Q10, gingerol, and isoquercetin. This review should serve as a compelling argument for the future study of natural supplements in APS.

Clinical management of feline chronic kidney disease in Portugal: a questionnaire-based study

OBJECTIVES

The aim of the study was to characterise the clinical management of feline chronic kidney disease (CKD) by veterinary practitioners in Portugal.

METHODS

A questionnaire-based study was designed to be completed by all veterinarians who had diagnosed and treated at least one case of feline CKD in the previous year.

RESULTS

A total of 409 veterinary practitioners responded to the questionnaire, with approximately half of them diagnosing 2-5 cases of feline CKD per month (n = 219, 53.5%). Although a high proportion of these reported using the guidelines published by the International Renal Interest Society (n = 379, 92.7%), only 19.1% (n = 78) systematically performed systolic blood pressure (SBP) measurements in all of their patients. A renal diet was advised by almost all respondents (n = 406, 99.3%), but 36.9% (n = 150) of them considered that it represented less than 75% of the daily food intake for most of their patients. This dietary intervention was often prescribed regardless of stage (n = 298, 73.4%) and without a proper gradual diet transition. Appetite stimulants were frequently prescribed (n = 366, 89.5%), as well as a calcium channel blocker (n = 171, 41.8%) and an angiotensin-converting enzyme inhibitor (n = 245, 59.9%) to control systemic hypertension and proteinuria, respectively. Prescription of a phosphate binder was also common (n = 311, 76.0%). Regarding monitoring, 70.9% (n = 290) recommended that stable patients be reassessed every 2-3 months or more frequently, but only 35.7% (n = 146) were able to comply with this periodicity due to owners' constraints.

CONCLUSIONS AND RELEVANCE

The findings showed that although most survey respondents are aware of international guidelines for the clinical management of cats with CKD, the SBP measurement still needs to be more systematic to allow proper substaging and detection of systemic hypertension. The monitoring frequency was lower than recommended. Furthermore, the introduction of a renal therapeutic diet should be refined to improve its acceptance rate.

n-3 PUFA-Enriched Diet Preserves Skeletal Muscle Mitochondrial Function and Redox State and Prevents Muscle Mass Loss in Mice with Chronic Heart Failure

Rationale and Methods: Skeletal muscle derangements, potentially including mitochondrial dysfunction with altered mitochondrial dynamics and high reactive oxygen species (ROS) generation, may lead to protein catabolism and muscle wasting, resulting in low exercise capacity and reduced survival in chronic heart failure (CHF). We hypothesized that 8-week n-3-PUFA isocaloric partial dietary replacement (Fat = 5.5% total cal; EPA + DHA = 27% total fat) normalizes gastrocnemius muscle (GM) mitochondrial dynamics regulators, mitochondrial and tissue pro-oxidative changes, and catabolic derangements, resulting in preserved GM mass in rodent CHF [Myocardial infarction (MI)-induced CHF by coronary artery ligation, left-ventricular ejection fraction <50%]. Results: Compared to control animals (Sham), CHF had a higher GM mitochondrial fission-fusion protein ratio, with low ATP and high ROS production, pro-inflammatory changes, and low insulin signalling. n-3-PUFA normalized all mitochondrial derangements and the pro-oxidative state (oxidized to total glutathione ratio), associated with normalized GM cytokine profile, and enhanced muscle-anabolic insulin signalling and prevention of CHF-induced GM weight loss (all p < 0.05 vs. CHF and p = NS vs. S). Conclusions:n-3-PUFA isocaloric partial dietary replacement for 8 weeks normalizes CHF-induced derangements of muscle mitochondrial dynamics regulators, ROS production and function. n-3-PUFA mitochondrial effects result in preserved skeletal muscle mass, with potential to improve major patient outcomes in clinical settings.

Fatty acids act on vascular endothelial cells and influence the development of cardiovascular disease

Endothelial cells (ECs) maintain the health of blood vessels and prevent the development of cardiovascular disease (CVD). Free saturated fatty acids (FAs) induce EC damage and increase the risk of CVD by promoting arteriosclerosis. Conversely, polyunsaturated FAs (PUFAs), such as docosahexaenoic acid, are thought to suppress EC damage induced during the early stages of CVD. This review describes the effects of multiple dietary FAs on EC disorders involved in the development of CVD. The roles of FAs in atherosclerosis and CVD were analyzed by evaluating articles published in PubMed, Science Direct, and Web of Science. Saturated FAs were found to induce EC damage by reducing the production and action of EC-derived nitric oxide. Oxidative stress, inflammation, and the renin-angiotensin system were found to be involved in EC disorder. Furthermore, n-3 PUFAs were found to reduce EC dysfunction and prevent the development of EC disorder. These results indicate that FAs may affect EC failure induced during the early stages of CVD and reduce the risk of developing the disease.

Physiological Doses of Oleic and Palmitic Acids Protect Human Endothelial Cells from Oxidative Stress

Oxidative stress has been proposed to be a pathogenic mechanism to induce endothelial dysfunction and the onset of cardiovascular disease. Elevated levels of free fatty acids can cause oxidative stress by increasing mitochondrial uncoupling but, at physiological concentrations, they are essential for cell and tissue function and olive oil free fatty acids have proved to exhibit beneficial effects on risk factors for cardiovascular disease. We hypothesize that realistic concentrations within the physiological range of oleic (OA) and palmitic (PA) acids could be beneficial in the prevention of oxidative stress in vascular endothelium. Hence, pre-treatment and co-treatment with realistic physiological doses of palmitic and oleic acids were tested on cultured endothelial cells submitted to a chemically induced oxidative stress to investigate their potential chemo-protective effect. Cell viability and markers of oxidative status: reactive oxygen species (ROS), reduced glutathione (GSH), malondialdehyde (MDA), glutathione peroxidase (GPx) and glutathione reductase (GR) were evaluated. As a conclusion, the increased ROS generation induced by stress was significantly prevented by a pre- and co-treatment with PA or OA. Moreover, pre- and co-treatment of cells with FFAs recovered the stress-induced MDA concentration to control values and significantly recovered depleted GSH and normalized GPx and GR activities. Finally, pre- and co-treatment of cells with physiological concentrations of PA or OA in the low micromolar range conferred a substantial protection of cell viability against an oxidative insult.

n-3 PUFA dietary lipid replacement normalizes muscle mitochondrial function and oxidative stress through enhanced tissue mitophagy and protects from muscle wasting in experimental kidney disease

INTRODUCTION AND METHODS

Skeletal muscle mitochondrial dysfunction may cause tissue oxidative stress and consequent catabolism in chronic kidney disease (CKD), contributing to patient mortality. We investigated in 5/6-nephrectomized (Nx) rats the impact of n3-polyunsaturated fatty-acids (n3-PUFA) isocaloric partial dietary replacement on gastrocnemius muscle (Gm) mitochondrial master-regulators, ATP production, ROS generation and related muscle-catabolic derangements.

RESULTS

Nx had low Gm mitochondrial nuclear respiratory factor-2 and peroxisome proliferator-activated receptor gamma coactivator-1alpha, low ATP production and higher mitochondrial fission-fusion protein ratio with ROS overproduction. n3-PUFA normalized all mitochondrial derangements and pro-oxidative tissue redox state (oxydized to total glutathione ratio). n3-PUFA also normalized Nx-induced muscle-catabolic proinflammatory cytokines, insulin resistance and low muscle weight. Human uremic serum reproduced mitochondrial derangements in C2C12 myotubes, while n3-PUFA coincubation prevented all effects. n3-PUFA also enhanced muscle mitophagy in-vivo and siRNA-mediated autophagy inhibition selectively blocked n3-PUFA-induced normalization of C2C12 mitochondrial ROS production.

CONCLUSIONS

In conclusion, dietary n3-PUFA normalize mitochondrial master-regulators, ATP production and dynamics in experimental CKD. These effects occur directly in muscle cells and they normalize ROS production through enhanced mitophagy. Dietary n3-PUFA mitochondrial effects result in normalized catabolic derangements and protection from muscle wasting, with potential positive impact on patient survival.

Nitrotyrosine, Nitrated Lipoproteins, and Cardiovascular Dysfunction in Patients with Type 2 Diabetes: What Do We Know and What Remains to Be Explained?

Diabetes mellitus (DM) is a strong risk factor for the development of cardiovascular diseases (CVDs), which are the most important cause of morbidity and mortality in the population of patients living with DM. DM is associated with lipid metabolism disorders characterized by a decrease in the high-density lipoprotein blood concentration, an increase in the triglyceride blood concentration, and the presence of modified lipoproteins not routinely measured in clinical practice. Nitrated lipoproteins are produced by the nitration of the tyrosyl residues of apolipoproteins by myeloperoxidase. There is some evidence from the research conducted showing that nitrated lipoproteins may play a role in the development of cardiovascular dysfunction, but this issue requires further investigation. It was found that the nitration of HDL particles was associated with a decrease in caspase-3 and paraoxonase-1 activity, as well as a decrease in the activity of cholesterol transport via ABCA1, which reduces the protective effect of HDL particles on the cardiovascular system. Less information has been collected about the role of nitrated LDL particles. Thus far, much more information has been obtained on the relationship of nitrotyrosine expression with the presence of cardiovascular risk factors and the development of cardiovascular dysfunction. The purpose of this paper is to provide an extensive review of the literature and to present the most important information on the current state of knowledge on the association between nitrotyrosine and nitrated lipoproteins with dysfunction of the cardiovascular system, especially in patients living with DM. Moreover, directions for future research in this area were discussed.

Effects of ω-3 PUFA-Rich Oil Supplementation on Cardiovascular Morphology and Aortic Vascular Reactivity of Adult Male Rats Submitted to an Hypercholesterolemic Diet

Simple Summary

Currently, processed and ultraprocessed foods represent a significant component of the diet of modern societies, increasing the risk of developing obesity, diabetes and atherosclerosis. Therefore, replacing saturated fats with mono- and polyunsaturated fats, such as omega-3 polyunsaturated fatty acids (ω-3 PUFAs), has been considered as a dietary strategy to reduce clinical events related to atherosclerosis. In the present study, the effects of 56-day ω-3 PUFA-rich oil supplementation on liver function, lipid profile, and oxidative stress in hypercholesterolemic rats were investigated, as well as its impact on cardiovascular health. Interestingly, we observed a positive effect in reducing hepatic markers, preserving cardiovascular morphology, and increasing vasodilator responsiveness. These findings contribute to the generation of consistent recommendations for the therapeutic use of ω-3 PUFAs in the treatment of atherosclerosis, leading to a consequent reduction in related morbidity and mortality.

Abstract

Atherosclerosis is a cardiovascular disease associated with abnormalities of vascular functions. The consumption of mono- and polyunsaturated fatty acids can be considered a strategy to reduce clinical events related to atherosclerosis. In the present study, we investigated the effects of supplementation with 310 mg of ω-3 PUFAs (2:1 eicosapentaenoic/docosahexaenoic acids) for 56 days on rats with hypercholesterolemia induced by a diet containing cholesterol (0.1%), cholic acid (0.5%), and egg yolk. Serum biochemical parameters were determined by the enzymatic colorimetric method. Assessment of vascular effects was performed by analysis of histological sections of the heart and aortic arch stained with hematoxylin and eosin and vascular reactivity of the aorta artery. We observed that treatment with ω-3 PUFAs did not promote alterations in lipid profile. On the other hand, we documented a favorable reduction in liver biomarkers, as well as contributions to the preservation of heart and aortic arch morphologies. Interestingly, the vascular reactivity of rat thoracic aortic preparations was improved after treatment with ω-3 PUFAs, with a decrease in hyperreactivity to phenylephrine and increased vasorelaxation promoted by acetylcholine. Our findings suggest that the supplementation of hypercholesterolemic rats with ω-3 PUFAs promoted improvement in liver and vascular endothelial function as well as preserving heart and aortic tissue, reinforcing the early health benefits of ω-3 PUFAs in the development of atherosclerotic plaque and further related events.

Dietary Omega-3 Fatty Acid Intake and Mortality in CKD Population: A 1999-2014 NHANES Analysis

INTRODUCTION

High risk of early death, especially contributed to cardiovascular disease, exists in patients who have chronic kidney disease (CKD). And the burden of cardiovascular disease is able to be lightened by an increase in omega-3 polyunsaturated fatty acid (omega-3 PUFA). A diet high in omega-3 PUFA in the general population is protective, although it is inconclusive about its beneficial role in the CKD population.

METHODS

From the 1999 to 2014 National Health and Nutrition Examination Surveys (NHANES), we can collect 2,990 participants who suffered from CKD, who were classified into 4 groups: <0.86, 0.87-1.30, 1.31-1.92, and 1.93-9.65 g/day based on NHANES 24-h dietary recall questionnaire dietary omega-3 PUFA. Moreover, their mortality details were available to be obtained by linking NHANES to the National Death Index. The associations between dietary omega-3 PUFA and mortality were evaluated by constructing multivariable Cox proportional hazards models.

RESULTS

Over 8 years of a median follow-up, 864 deaths were recorded. The adjusted hazard ratios (95% confidence interval) for all-cause mortality of the diseased people with CKD in the 2nd (0.87-1.30 g/day), 3rd (0.87-1.30 g/day), and 4th (1.93-9.65 g/day) quartiles of dietary omega-3 PUFA were 0.94 (0.72, 1.23), 0.74 (0.54, 1.02), and 0.67 (0.48, 0.93), respectively, versus those with the lowest quartile of dietary omega-3 PUFA intake (<0.86 g/day) (p for trend = 0.011).

CONCLUSION

There may be a inverse relation of dietary omega-3 PUFA intake and all-cause mortality in patients with CKD. Therefore, an increase of dietary omega-3 PUFA may be encouraged to be used clinically in patients with CKD.

Erythropoietin therapy improves endothelial function in patients with non-dialysis chronic kidney disease and anemia (EARNEST-CKD): A clinical study

BACKGROUND

This study investigated whether administering erythropoiesis-stimulating agents (ESAs) improves endothelial function in patients with non-dialysis chronic kidney disease (CKD) and anemia.

METHODS

This single-center, prospective, single-arm comparison study enrolled patients with non-dialysis CKD (stages 4-5) and hemoglobin levels <10 g/dL. ESA administration followed the Kidney Disease: Improving Global Outcomes guideline. The primary endpoint was the change in flow-mediated dilatation after ESA administration in individual patients. The secondary endpoints were changes in 6-minute walk test results, blood pressure, New York Heart Association class, and echocardiographic parameters. The echocardiographic parameters examined included chamber quantification, Doppler parameters, and systolic and diastolic function parameters.

RESULTS

Initially, 13 patients were screened, but 2 discontinued due to either heart failure or voluntary withdrawal. The mean flow-mediated dilatation values significantly increased by 10.59% (from 1.36% ± 1.91% to 11.95% ± 8.11%, P = .001). Echocardiographic findings showed that the left ventricular mass index decreased by 11.9 g/m2 (from 105.8 ± 16.3 to 93.9 ± 19.5 g/m2, P  =  .006), and the left atrial volume index decreased by 10.8 mL/m2 (from 50.1 ± 11.3 to 39.3 ± 11.3 mL/m2, P = .004) after 12 weeks of ESA administration. There were no significant differences between pre- and post-ESA treatment 6-minute walk test results. No significant side effects were observed during the study period.

CONCLUSIONS

This is the first clinical study to demonstrate that an ESA improves endothelial dysfunction, left ventricular hypertrophy, and left atrial volume in patients with non-dialysis CKD. Thus, ESAs may be considered as adjunctive therapy for reducing cardiovascular risk in these patients.

The Use of Chinese Yang/Qi-Invigorating Tonic Botanical Drugs/Herbal Formulations in Ameliorating Chronic Kidney Disease by Enhancing Mitochondrial Function

Background: Chronic kidney disease (CKD) is a leading cause of morbidity and mortality. Mitochondrial dysfunction has been implicated as a key factor in the development of CKD. According to traditional Chinese medicine (TCM) theory, many Chinese Yang/Qi-invigorating botanical drugs/herbal formulations have been shown to produce promising outcomes in the clinical management of CKD. Experimental studies have indicated that the health-promoting action of Yang/Qi invigoration in TCM is related to the up-regulation of mitochondrial energy generation and antioxidant status. Objective: In this review, we aim to test whether Chinese Yang/Qi-invigorating tonic botanical drugs/herbal formulations can provide medical benefits in CKD and its complications. And we also explore the possible involvement of mitochondrial-associated signaling pathway underlying the beneficial effects of Yang/Qi invigoration in TCM. Methods: A systematic search of "PubMed", "China National Knowledge Infrastructure (CNKI)" and "Google Scholar" was carried out to collect all the available articles in English or Chinese related to Chinese Yang/Qi-invigorating tonic botanical drugs/herbal formulations and their effects on mitochondrial function and chronic kidney disease. Result and Discussion: The relationship between the progression of CKD and mitochondrial function is discussed. The effects of Chinese Yang/Qi-invigorating tonic botanical drugs/herbal formulations and their active ingredients, including phytosterols/triterpenes, flavonoids, and dibenzocyclooctadiene lignans, on CKD and related alterations in mitochondrial signaling pathways are also presented in this review. In the future, exploration of the possible beneficial effects and clinical studies of more Yang- and Qi-invigorating botanical drugs/herbal formulations in the prevention and/or/treatment of CKD and the molecular mechanisms relating to the enhancement of mitochondrial functions warrants further investigation. Conclusion: Given the critical role of mitochondrial function in safeguarding renal functional integrity, the enhancement of mitochondrial energy metabolism and antioxidant status in kidney tissue is likely involved in renal protection. Future studies on the biochemical and chemical basis underlying the effects of Chinese Yang/Qi-invigorating tonic botanical drugs/herbal formulations from a mitochondrial perspective will hopefully provide novel insights into the rational development of new drugs for the prevention and/or treatment of CKD.

Polyporus Umbellatus Protects Against Renal Fibrosis by Regulating Intrarenal Fatty Acyl Metabolites

Background: Chronic renal failure (CRF) results in significant dyslipidemia and profound changes in lipid metabolism. Polyporus umbellatus (PPU) has been shown to prevent kidney injury and subsequent kidney fibrosis.

Methods: Lipidomic analysis was performed to explore the intrarenal profile of lipid metabolites and further investigate the effect of PPU and its main bioactive component, ergone, on disorders of lipid metabolism in rats induced by adenine. Univariate and multivariate statistical analyses were performed for choosing intrarenal differential lipid species in CRF rats and the intervening effect of n-hexane extract of PPU and ergone on CRF rats.

Results: Compared with control group, decreased creatinine clearance rate indicated declining kidney function in CRF group. Based on the lipidomics, we identified 65 lipid species that showed significant differences between CRF and control groups. The levels of 12 lipid species, especially fatty acyl lipids including docosahexaenoic acid, docosapentaenoic acid (22n-3), 10,11-Dihydro-12R-hydroxy-leukotriene C4, 3-hydroxydodecanoyl carnitine, eicosapentaenoic acid, hypogeic acid and 3-hydroxypentadecanoic acid had a strong linear correlation with creatinine clearance rate, which indicated these lipid species were associated with impaired renal function. In addition, receiver operating characteristics analysis showed that 12 lipid species had high area under the curve values with high sensitivity and specificity for differentiating CRF group from control group. These changes are related to the perturbation of fatty acyl metabolism. Treatment with PPU and ergone improved the impaired kidney function and mitigated renal fibrosis. Both chemometrics and cluster analyses showed that rats treated by PPU and ergone could be separated from CRF rats by using 12 lipid species. Intriguingly, PPU treatment could restore the levels of 12 lipid species, while treatment with ergone could only reverse the changes of six fatty acids in CRF rats.

Conclusion: Altered intrarenal fatty acyl metabolites were implicated in pathogenesis of renal fibrosis. PPU and ergone administration alleviated renal fibrosis and partially improved fatty acyl metabolism. These findings suggest that PPU exerted its renoprotective effect by regulating fatty acyl metabolism as a potential biochemical mechanism. Therefore, these findings indicated that fatty acyl metabolism played an important role in renal fibrosis and could be considered as an effective therapeutic avenue against renal fibrosis.

Are Nutraceuticals Beneficial in Chronic Kidney Disease?

Chronic kidney disease (CKD) is a worldwide health problem in which prevalence is constantly rising. The pathophysiology of CKD is complicated and has not been fully resolved. However, elevated oxidative stress is considered to play a vital role in the development of this disease. CKD is also thought to be an inflammatory disorder in which uremic toxins participate in the development of the inflammatory milieu. A healthy, balanced diet supports the maintenance of a good health status as it helps to reduce the risk of the development of chronic diseases, including chronic kidney disease, diabetes mellitus, and hypertension. Numerous studies have demonstrated that functional molecules and nutrients, including fatty acids and fiber as well as nutraceuticals such as curcumin, steviol glycosides, and resveratrol not only exert beneficial effects on pro-inflammatory and anti-inflammatory pathways but also on gut mucosa. Nutraceuticals have attracted great interest recently due to their potential favorable physiological effects on the human body and their safety. This review presents some nutraceuticals in which consumption could exert a beneficial impact on the development and progression of renal disease as well cardiovascular disease.

Membrane modulatory effects of omega-3 fatty acids: Analysis of molecular level interactions

Bioactive omega-3 polyunsaturated fatty acids have been shown to reduce the risk of death in patients with cardiovascular disease and alleviate the symptoms of other inflammatory diseases. However, the mechanisms of action of these effects remain unclear. It has been postulated that omega-3 polyunsaturated fatty acids modify cell membranes by incorporation into the membrane and altering the signaling properties of cellular receptors. In this chapter, we explore the effects of omega-3 polyunsaturated fatty acids on cell membrane structure and function. We present a review of the current evidence for the health benefits of these compounds and explore the molecular mechanisms through which omega-3 polyunsaturated fatty acids interact with membrane lipids and modulate bilayer structure. Using computational models of multicomponent phospholipid bilayers, we assess the consequences of incorporation of these fatty acids on membrane lipid packing, water permeation, and membrane structure.

Endothelial Dysfunction in Chronic Kidney Disease, from Biology to Clinical Outcomes: A 2020 Update

The vascular endothelium is a dynamic, functionally complex organ, modulating multiple biological processes, including vascular tone and permeability, inflammatory responses, thrombosis, and angiogenesis. Endothelial dysfunction is a threat to the integrity of the vascular system, and it is pivotal in the pathogenesis of atherosclerosis and cardiovascular disease. Reduced nitric oxide (NO) bioavailability is a hallmark of chronic kidney disease (CKD), with this disturbance being almost universal in patients who reach the most advanced phase of CKD, end-stage kidney disease (ESKD). Low NO bioavailability in CKD depends on several mechanisms affecting the expression and the activity of endothelial NO synthase (eNOS). Accumulation of endogenous inhibitors of eNOS, inflammation and oxidative stress, advanced glycosylation products (AGEs), bone mineral balance disorders encompassing hyperphosphatemia, high levels of the phosphaturic hormone fibroblast growth factor 23 (FGF23), and low levels of the active form of vitamin D (1,25 vitamin D) and the anti-ageing vasculoprotective factor Klotho all impinge upon NO bioavailability and are critical to endothelial dysfunction in CKD. Wide-ranging multivariate interventions are needed to counter endothelial dysfunction in CKD, an alteration triggering arterial disease and cardiovascular complications in this high-risk population.

A novel eicosapentaenoic acid-derived anti-inflammatory lipid mediator 5,6-DiHETE is abundant in blue back fish intestines

Because omega-3 fatty acids, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and their metabolites are known to possess anti-inflammatory and health-promoting functions in human and experimental animals, their intake is assumed to be beneficial for maintaining our health. We previously identified a cytochrome P450-metabolite of EPA, 5,6-dihydroxy-8Z,11Z,14Z,17Z-eicosatetraenoic acid (5,6-DiHETE), as a novel bioactive lipid, which inhibits vascular hyperpermeability in inflammation. Because blue back fishes including sardine, mackerel, and horse mackerel are reported to contain high concentrations of omega-3 fatty acids, we investigated which tissue of blue back fish is suitable as a source of 5,6-DiHETE. We measured the concentration of 5,6-DiHETE as well as major fatty acids in muscle, bone, heart, liver, and intestine of blue back fishes. Arachidonic acid was detected richer in intestines than other tissues of blue back fishes. The concentrations were between 4.45 and 5.62 µg/g tissue weight. EPA and DHA are also detected richer in intestines of blue back fishes. The concentrations were between 75.95 and 358.04 µg/g, and 203.09 and 464.88 µg/g, respectively. Especially, mackerel intestine contained the highest levels of both EPA and DHA. 5,6-DiHETE was present in greater amount in livers and intestines of blue back fishes. The livers contained 118.98 to 476.11 ng/g, whereas intestines contained 156.14 to 970.22 ng/g of 5,6-DiHETE. Of interest, sardine intestine contained much higher level of 5,6-DiHETE than the other fish tissues. These results suggest that visceral organs of blue back fishes, remarkably sardine intestine, can be a good source of 5,6-DiHETE. PRACTICAL APPLICATION: A novel anti-inflammatory lipid, 5,6-DiHETE, was detected in each tissues of blue back fishes. Especially their intestines contain the highest concentration of this lipid.

A Mixture of Algae and Extra Virgin Olive Oils Attenuates the Cardiometabolic Alterations Associated with Aging in Male Wistar Rats

Aging is one of the major risk factors for suffering cardiovascular and metabolic diseases. Due to the increase in life expectancy, there is a strong interest in the search for anti-aging strategies to treat and prevent these aging-induced disorders. Both omega 3 polyunsaturated fatty acids (ω-3 PUFA) and extra virgin olive oil (EVOO) exert numerous metabolic and cardiovascular benefits in the elderly. In addition, EVOO constitutes an interesting ingredient to stabilize ω-3 PUFA and decrease their oxidation process due to its high content in antioxidant compounds. ω-3 PUFA are commonly obtained from fish. However, more ecological and sustainable sources, such as algae oil (AO) can also be used. In this study, we aimed to study the possible beneficial effect of an oil mixture composed by EVOO (75%) and AO (25%) rich in ω-3 PUFA (35% docosahexaenoic acid (DHA) and 20% eicosapentaenoic acid (EPA)) on the cardiometabolic alterations associated with aging. For this purpose; young (three months old) and old (24 months old) male Wistar rats were treated with vehicle or with the oil mixture (2.5 mL/kg) for 21 days. Treatment with the oil mixture prevented the aging-induced increase in the serum levels of saturated fatty acids (SFA) and the aging-induced decrease in the serum concentrations of mono-unsaturated fatty acids (MUFA). Old treated rats showed increased serum concentrations of EPA and DHA and decreased HOMA-IR index and circulating levels of total cholesterol, insulin and IL-6. Treatment with the oil mixture increased the mRNA levels of antioxidant and insulin sensitivity-related enzymes, as well as reduced the gene expression of pro-inflammatory markers in the liver and in cardiac and aortic tissues. In addition, the treatment also prevented the aging-induced endothelial dysfunction and vascular insulin resistance through activation of the PI3K/Akt pathway. Moreover, aortic rings from old rats treated with the oil mixture showed a decreased response to the vasoconstrictor AngII. In conclusion, treatment with a mixture of EVOO and AO improves the lipid profile, insulin sensitivity and vascular function in aged rats and decreases aging-induced inflammation and oxidative stress in the liver, and in the cardiovascular system. Thus, it could be an interesting strategy to deal with cardiometabolic alterations associated with aging.

Effects of walnut oil on metabolic profile and transcription factors in rats fed high-carbohydrate-/-fat diets

The aim of this study was to examine the effects of walnut oil (WO) on metabolic profile and transcription factors in rats fed high carbohydrate (HCD) and high-fat diet (HFD). Forty-two male rats were divided in to six groups: (a) Control, (b) WO (20 mg/kg BW), (c) HCD (20% of sucrose), (d) HCD + WO (e) HFD (42% of calories as fat), and (f) HFD + WO. HFD and HCD intake increased final body weights by 19% and 23% and visceral fat weights by 3- and 5-fold, respectively (p < .05 for all). In addition, serum glucose, total cholesterol, triglyceride, and free fatty acids (FFA) insulin, leptin, and MDA levels increased in rats fed with HFD and HCD. WO supplementation improved these metabolic parameters (p < .05 for all). HFD + WO and HCD + WO treated groups had a significant reduction in serum and liver malondialdehyde (MDA) levels by 12% or 15% (p < .05 for both). In addition, WO supplementation lowered the levels of hepatic nuclear factor kappa B (NF-κB) and NADPH oxidase subunit p22^phox , whereas increased the endothelial-NO synthase (e-NOS), nuclear factor erythroid 2-related factor-2, and sirtuin-1 levels. In conclusion, WO supplementation could alleviate the adverse impacts of both HCD and HFD in the rats. PRACTICAL APPLICATIONS: This study suggests that WO intake can modulate carbohydrate metabolism and increase antioxidant capacity. These properties might be partially mediated through the regulation of the transcription factors and some proteins involved in energy metabolism, as well as a balance of oxidative stress, and insulin sensitivity.

Blood pressure modifies outcomes in patients with stage 3 to 5 chronic kidney disease

Observational studies have demonstrated that low blood pressure is related to poor clinical outcomes in patients with chronic kidney disease (CKD). Subgroup analyses from the SPRINT trial showed that targeting systolic blood pressure under 120 mmHg is less beneficial for patients with CKD. Although malnutrition and inflammation are common in patients with advanced CKD, such patients are usually excluded from clinical trials. Therefore, we hypothesized that malnutrition-inflammation-cachexia syndrome could explain this J-shaped relationship. To test this, we studied 2441 patients with CKD stages 3-5 who received anti-hypertensive treatment for at least one year. Averaged blood pressures of the first year were used in the analyses. Fine-Gray competing risks regression showed a J-shaped relationship between continuous systolic blood pressure and end-stage kidney disease (ESKD) with a nadir risk at a systolic blood pressure of 120 mmHg. Adjusted sub-distribution hazard ratios of categorical systolic blood pressure 100-109 and 110-119 mmHg were 2.17 (95% confidence interval: 1.21-3.89) and 1.37 (0.94-1.99) for ESKD, respectively, compared with systolic blood pressures of 120-129 mmHg. Cox regression also showed J-shaped relationships between continuous systolic or diastolic blood pressures, and the composite outcomes of cardiovascular events and all-cause mortality. Logistic regression demonstrated the odds ratios of blood pressure components for Malnutrition-Inflammation Scores over 4 were J-shaped. Sub-distribution hazard ratios of systolic blood pressure 100-119 mmHg for ESKD was higher in those with a Malnutrition-Inflammation Score over 4, compared to 0.93 (0.53-1.63) in those with a score of 4 or under with significant interaction. Thus, malnutrition-inflammation-cachexia syndrome is associated with low blood pressure and modifies the J-shaped relationship in patients with advanced CKD.

Lipid Accumulation and Chronic Kidney Disease

Obesity and hyperlipidemia are the most prevalent independent risk factors of chronic kidney disease (CKD), suggesting that lipid accumulation in the renal parenchyma is detrimental to renal function. Non-esterified fatty acids (also known as free fatty acids, FFA) are especially harmful to the kidneys. A concerted, increased FFA uptake due to high fat diets, overexpression of fatty acid uptake systems such as the CD36 scavenger receptor and the fatty acid transport proteins, and a reduced β-oxidation rate underlie the intracellular lipid accumulation in non-adipose tissues. FFAs in excess can damage podocytes, proximal tubular epithelial cells and the tubulointerstitial tissue through various mechanisms, in particular by boosting the production of reactive oxygen species (ROS) and lipid peroxidation, promoting mitochondrial damage and tissue inflammation, which result in glomerular and tubular lesions. Not all lipids are bad for the kidneys: polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) seem to help lag the progression of chronic kidney disease (CKD). Lifestyle interventions, especially dietary adjustments, and lipid-lowering drugs can contribute to improve the clinical outcome of patients with CKD.

Effects of a New Combination of Medical Food on Endothelial Function and Lipid Profile in Dyslipidemic Subjects: A Pilot Randomized Trial

Nutritional approaches to improve dyslipidemias have been recently developed, but evidences on different medical foods are often incomplete. The main aim of our study was to evaluate the effects on endothelial function, lipid profile, and glucose metabolism of two different combinations of nutraceuticals, first one containing Bergavit (200 mg Citrus bergamia), Omega-3 (400 mg), Crominex 3+ (10 mcg trivalent chromium), and red yeast rice (100 mg; 5 mg monacolin K) and second one containing red yeast rice (200 mg; 3 mg monacolin K), Berberine (500 mg), Astaxanthin (0.5 mg), folic acid (200 mcg), Coenzyme Q10 (2 mg), and Policosanol (10 mg). Fifty subjects affected by dyslipidemia not requiring statin treatment were enrolled in this randomized, blind, controlled trial and submitted to blood sampling for lipid and glucose profiles and instrumental evaluation of endothelial function before and after 6 weeks of treatment with nutraceuticals. Both nutraceutical combinations improved the lipid profile; the nutraceutical containing 5 mg of monacolin K, 200 mg of the extract Citrus bergamia, 400 mg of Omega-3, and 10 mcg of trivalent chromium entailed a significant improvement of endothelial function with enhanced cholesterol lowering effect. In conclusion, this study confirms the positive effect of functional food on lipid profile and endothelial function in absence of major undesirable effects.

Increased circulating trimethylamine N-oxide contributes to endothelial dysfunction in a rat model of chronic kidney disease

Chronic kidney disease (CKD) is strongly associated with increased cardiovascular risk. Impaired endothelial function, a key initiating step in the pathogenesis of cardiovascular disease, has been reported in patients with CKD, but the mechanisms responsible for endothelial dysfunction in CKD remain elusive. Emerging evidence reveals that trimethylamine-N-oxide (TMAO), a gut microbiota-generated metabolite, is involved in the pathogenesis of many cardiovascular diseases. Circulating TMAO is elevated in CKD. Here we tested the hypothesis that elevated TMAO plays a contributory role in the pathogenesis of endothelial dysfunction in CKD. Rats underwent 5/6 nephrectomy to induce CKD or sham operation, and were treated with 1.0% 3,3-Dimethyl-1-butanol (DMB, an inhibitor of trimethylamine formation) or vehicle. Eight weeks after nephrectomy and DMB treatment, circulating TMAO levels were markedly elevated in CKD-vehicle rats compared with sham-vehicle rats, but were reduced in CKD-DMB rats. Acetylcholine-induced endothelium-dependent vasodilation was impaired in CKD-vehicle rats compared with sham-vehicle rats as indicated by reduced maximal relaxation (E_max) and decreased area under the curve (AUC). E_max and AUC were both normalized in CKD-DMB rats. No difference in sodium nitroprusside-induced endothelial-independent vasodilation was observed across groups. Molecular studies revealed that endothelial nitric-oxide synthase activity was decreased, while superoxide production and proinflammatory cytokine expression were increased in the aorta of CKD-vehicle rats compared with sham-vehicle rats. Of note, the abnormalities in above molecular parameters were completely restored in CKD-DMB rats. These results suggest that CKD elevates circulating TMAO levels, which may reduce eNOS-derived NO production by increasing vascular oxidative stress and inflammation, contributing to CKD-associated endothelial dysfunction and cardiovascular disease.

Evaluation of the Effectiveness of Xanthine Oxidoreductase Inhibitors on Haemodialysis Patients using a Marginal Structural Model

A lower serum uric acid (UA) level has been associated with a higher mortality rate in haemodialysis patients. We investigated the long-term confounding factors of UA and mortality, and fitted a marginal structural model (MSM) based on the causal effect of xanthine oxidoreductase inhibitors (XORi). In total, 2429 patients on regular dialysis from April 2013 to March 2016 were included, and divided into quintiles by serum UA with Kaplan Meier (KM) curves and log rank analysis. Baseline characteristics were evaluated for relationships with all-cause mortality and cardiovascular disease (CVD) using the Cox hazard model. The MSM was used to control for time-dependent confounders of the XORi treatment effect. KM curves indicated that patients in the highest UA quintile had better outcomes than those in the lowest UA quintile. UA was not correlated with all-cause mortality or CVD events in the Cox model; however, the hazard ratio (HR) for mortality was 0.96 for the baseline administration of XORi. The MSM analysis for the effect of XORi treatment on all-cause mortality revealed a HR of 0.24 (95% confidence interval: 0.15-0.38) in all cohorts. These results suggest that XORi improved all-cause mortality in end-stage renal disease, irrespective of the serum UA level.