Secondary prevention with antioxidants of cardiovascular disease in endstage renal disease (SPACE): randomised placebo-controlled trial

Metabolic dysfunction-associated steatotic liver disease: An opportunity for collaboration between cardiology and hepatology

Altered metabolic function has many detrimental effects on the body that can manifest as cardiovascular and liver diseases. Traditional approaches to understanding and treating metabolic dysfunction-associated disorders have been organ-centered, leading to silo-type disease care. However, given the broad impact that systemic metabolic dysfunction has on the human body, approaches that simultaneously involve multiple medical specialists need to be developed and encouraged to optimize patient outcomes. In this review, we highlight how several of the treatments developed for cardiac care may have a beneficial effect on the liver and vice versa, suggesting that there is a need to target the disease process, rather than specifically target the cardiovascular or liver specific sequelae of metabolic dysfunction.

Ceruloplasmin, Vitamin C, and Uric Acid Levels in Patients With Myocardial Infarction: A Comparative Cross-Sectional Study

INTRODUCTION

Global mortality is significantly influenced by myocardial infarction. Scientists have examined the role of the copper-containing protein ceruloplasmin in heart attacks. It helps to regulate oxidative stress, iron metabolism, and inflammation. Vitamin C's antioxidative qualities lend credence to the idea that it could help prevent cardiovascular disease. Several studies have shown that elevated uric acid levels are related to a higher risk of myocardial infarction. With this background, we conducted this study to estimate levels of ceruloplasmin, vitamin C, and uric acid in patients with myocardial infarction.

MATERIALS AND METHODS

A tertiary care hospital in central India carried out this comparative cross-sectional study. The study was conducted between December 2022 and April 2023. Patients of any gender with newly diagnosed myocardial infarction who received admission to the intensive care unit and had ST-segment elevation of at least 2 mm in two or more consecutive electrocardiogram leads were included in the patient group. The control group consisted of individuals who did not exhibit any changes associated with myocardial infarction. Based on sex, age, and body mass index, the 75 control and 75 patients were matched. Ceruloplasmin, vitamin C, and uric acid were analyzed and compared.

RESULTS

The uric acid levels among the patient group were 10.34 ± 3.23 mg/dL, and among the controls, they were 3.45 ± 1.12 mg/dL (p<0.001). The ceruloplasmin levels among the patient group were 64.34 ± 4.21 mg/dL, and among the controls, they were 29.23 ± 3.82 mg/dL (p<0.001). The vitamin C levels among the patient group were 13.80 ± 0.94 μmol/L, and among the controls, they were 45.62 ± 4.34 μmol/L (p<0.001).

CONCLUSION

The patients with myocardial infarction demonstrated significantly elevated levels of ceruloplasmin and uric acid, while their vitamin C levels were lower in comparison. It is crucial to comprehend the underlying mechanisms through which these parameters influence the development of myocardial infarction.

Vitamin Supplement Use in Patients With CKD: Worth the Pill Burden?

All vitamins play essential roles in various aspects of body function and systems. Patients with chronic kidney disease (CKD), including those receiving dialysis, may be at increased risk of developing vitamin deficiencies due to anorexia, poor dietary intake, protein energy wasting, restricted diet, dialysis loss, or inadequate sun exposure for vitamin D. However, clinical manifestations of most vitamin deficiencies are usually subtle or undetected in this population. Testing for circulating levels is not undertaken for most vitamins except folate, B12, and 25-hydroxyvitamin D because assays may not be available or may be costly to perform and do not always correlate with body stores. The last systematic review through 2016 was performed for the Kidney Disease Outcome Quality Initiative (KDOQI) 2020 Nutrition Guideline update, so this article summarizes the more recent evidence. We review the use of vitamins supplementation in the CKD population. To date there have been no randomized trials to support the benefits of any vitamin supplementation for kidney, cardiovascular, or patient-centered outcomes. The decision to supplement water-soluble vitamins should be individualized, taking account the patient's dietary intake, nutritional status, risk of vitamins deficiency/insufficiency, CKD stage, comorbid status, and dialysis loss. Nutritional vitamin D deficiency should be corrected, but the supplementation dose and formulation need to be personalized, taking into consideration the degree of 25-hydroxyvitamin D deficiency, parathyroid hormone levels, CKD stage, and local formulation. Routine supplementation of vitamins A and E is not supported due to potential toxicity. Although more trial data are required to elucidate the roles of vitamin supplementation, all patients with CKD should undergo periodic assessment of dietary intake and aim to receive various vitamins through natural food sources and a healthy eating pattern that includes vitamin-dense foods.

Biomonitoring of Oxidative-Stress-Related Genotoxic Damage in Patients with End-Stage Renal Disease

Chronic kidney disease (CKD), a common progressive renal failure characterized by the permanent loss of functional nephrons can rapidly progress to end-stage renal disease, which is known to be an irreversible renal failure. In the therapy of ESRD, there are controversial suggestions about the use of regular dialysis, since it is claimed to increase oxidative stress, which may increase mortality in patients. In ESRD, oxidative-stress-related DNA damage is expected to occur, along with increased inflammation. Many factors, including heavy metals, have been suggested to exacerbate the damage in kidneys; therefore, it is important to reveal the relationship between these factors in ESRD patients. There are very few studies showing the role of oxidative-stress-related genotoxic events in the progression of ESRD patients. Within the scope of this study, genotoxic damage was evaluated using the comet assay and 8-OHdG measurement in patients with ESRD who were undergoing hemodialysis. The biochemical changes, the levels of heavy metals (aluminum, arsenic, cadmium, lead, and mercury) in the blood, and the oxidative biomarkers, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were evaluated, and their relationship with genotoxic damages was revealed. Genotoxicity, oxidative stress, and heavy-metal levels, except mercury, increased significantly in all renal patients. DNA damage, 8OHdG, and MDA significantly increased, and GSH significantly decreased in patients undergoing dialysis, compared with those not having dialysis. The duration and the severity of disease was positively correlated with increased aluminum levels and moderate positively correlated with increased DNA damage and cadmium levels. In conclusion, this study revealed that the oxidative-stress-related DNA damage, and also the levels of Al and Cd, increased in ESRD patients. It is assumed that these changes may play an important role in the progression of renal damage. Approaches for reducing oxidative-stress-related DNA damage and heavy-metal load in ESRD patients are recommended.

Inflammation: the driver of poor outcomes among children with severe acute malnutrition?

Severe acute malnutrition (SAM) is the most life-threatening form of undernutrition and underlies at least 10% of all deaths among children younger than 5 years in low-income countries. SAM is a complex, multisystem disease, with physiological perturbations observed in conjunction with the loss of lean mass, including structural and functional changes in many organ systems. Despite the high mortality burden, predominantly due to infections, the underlying pathogenic pathways remain poorly understood. Intestinal and systemic inflammation is heightened in children with SAM. Chronic inflammation and its consequent immunomodulation may explain the increased morbidity and mortality from infections in children with SAM, both during hospitalization and in the longer term after discharge. Recognition of the role of inflammation in SAM is critical in considering new therapeutic targets in this disease, which has not seen a transformational approach to treatment for several decades. This review highlights the central role of inflammation in the wide-ranging pathophysiology of SAM, as well as identifying potential interventions that have biological plausibility based on evidence from other inflammatory syndromes.

Antioxidants for adults with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a significant risk factor for cardiovascular disease (CVD) and death. Increased oxidative stress in people with CKD has been implicated as a potential causative factor. Antioxidant therapy decreases oxidative stress and may consequently reduce cardiovascular morbidity and death in people with CKD. This is an update of a Cochrane review first published in 2012.

OBJECTIVES

To examine the benefits and harms of antioxidant therapy on death and cardiovascular and kidney endpoints in adults with CKD stages 3 to 5, patients undergoing dialysis, and kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies until 15 November 2022 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised controlled trials investigating the use of antioxidants, compared with placebo, usual or standard care, no treatment, or other antioxidants, for adults with CKD on cardiovascular and kidney endpoints.

DATA COLLECTION AND ANALYSIS

Titles and abstracts were screened independently by two authors who also performed data extraction using standardised forms. Results were pooled using random effects models and expressed as risk ratios (RR) or mean difference (MD) with 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

We included 95 studies (10,468 randomised patients) that evaluated antioxidant therapy in adults with non-dialysis-dependent CKD (31 studies, 5342 patients), dialysis-dependent CKD (41 studies, 3444 patients) and kidney transplant recipients (21 studies, 1529 patients). Two studies enrolled dialysis and non-dialysis patients (153 patients). Twenty-one studies assessed the effects of vitamin antioxidants, and 74 assessed the effects of non-vitamin antioxidants. Overall, the quality of included studies was moderate to low or very low due to unclear or high risk of bias for randomisation, allocation concealment, blinding, and loss to follow-up. Compared with placebo, usual care, or no treatment, antioxidant therapy may have little or no effect on cardiovascular death (8 studies, 3813 patients: RR 0.94, 95% CI 0.64 to 1.40; I² = 33%; low certainty of evidence) and probably has little to no effect on death (any cause) (45 studies, 7530 patients: RR 0.95, 95% CI 0.82 to 1.11; I² = 0%; moderate certainty of evidence), CVD (16 studies, 4768 patients: RR 0.79, 95% CI 0.63 to 0.99; I² = 23%; moderate certainty of evidence), or loss of kidney transplant (graft loss) (11 studies, 1053 patients: RR 0.88, 95% CI 0.67 to 1.17; I² = 0%; moderate certainty of evidence). Compared with placebo, usual care, or no treatment, antioxidants had little to no effect on the slope of urinary albumin/creatinine ratio (change in UACR) (7 studies, 1286 patients: MD -0.04 mg/mmol, 95% CI -0.55 to 0.47; I² = 37%; very low certainty of evidence) but the evidence is very uncertain. Antioxidants probably reduced the progression to kidney failure (10 studies, 3201 patients: RR 0.65, 95% CI 0.41 to 1.02; I² = 41%; moderate certainty of evidence), may improve the slope of estimated glomerular filtration rate (change in eGFR) (28 studies, 4128 patients: MD 3.65 mL/min/1.73 m², 95% CI 2.81 to 4.50; I² = 99%; low certainty of evidence), but had uncertain effects on the slope of serum creatinine (change in SCr) (16 studies, 3180 patients: MD -13.35 µmol/L, 95% CI -23.49 to -3.23; I² = 98%; very low certainty of evidence). Possible safety concerns are an observed increase in the risk of infection (14 studies, 3697 patients: RR 1.30, 95% CI 1.14 to 1.50; I² = 3%; moderate certainty of evidence) and heart failure (6 studies, 3733 patients: RR 1.40, 95% CI 1.11 to 1.75; I² = 0; moderate certainty of evidence) among antioxidant users. Results of studies with a low risk of bias or longer follow-ups generally were comparable to the main analyses.

AUTHORS' CONCLUSIONS

We found no evidence that antioxidants reduced death or improved kidney transplant outcomes or proteinuria in patients with CKD. Antioxidants likely reduce cardiovascular events and progression to kidney failure and may improve kidney function. Possible concerns are an increased risk of infections and heart failure among antioxidant users. However, most studies were of suboptimal quality and had limited follow-up, and few included people undergoing dialysis or kidney transplant recipients. Furthermore, the large heterogeneity in interventions hampers drawing conclusions on the efficacy and safety of individual agents.

Clotting Propensity of Surface-Treated Membranes in a Hemodialysis Set-up That Avoids Systemic Anticoagulation

The development of biocompatible membranes, aiming to limit the inflammatory response, oxidative stress, and coagulability during hemodialysis, has been an important step in reducing dialysis-related adverse outcomes. This includes a reduction in the risk of clotting of the extracorporeal circuit, thus enabling hemodialysis with a reduced dose or even without systemic anticoagulant drugs in patients with an increased bleeding risk. In this article, we summarize the in vitro research and clinical evidence on the antithrombotic properties of vitamin E- and heparin-coated membranes.

Vitamin E Supplementation and Cardiovascular Health: A Comprehensive Review

This article conducts a thorough investigation into the potential role of vitamin E in preventing cardiovascular diseases (CVDs) in the context of shifting mortality patterns from infectious diseases to the continued prominence of CVDs in modern medicine. The primary focus is on vitamin E's antioxidant properties and its specific ability to counter lipid peroxidation, a pivotal process in the early stages of atherosclerosis, a precursor to CVDs. The research spans a wide range of methodologies, including in vitro, in vivo, clinical, and experimental studies, examining how vitamin E affects critical aspects of cardiovascular health, such as signaling pathways, gene expression, inflammation, and cholesterol metabolism. It also explores vitamin E's influence on complex processes like smooth muscle cell development, oxidative stress reduction, foam cell formation, and the stability of atherosclerotic plaques. In the context of clinical studies, the article presents findings that both support and yield inconclusive results regarding the impact of vitamin E supplementation on CVDs. It acknowledges the intricate interplay of factors such as patient selection, pathophysiological conditions, and genetic variations, all of which can significantly influence the efficacy of vitamin E. The article underscores the need for ongoing research, with a specific focus on understanding the regulatory metabolites of vitamin E and their roles in modulating cellular processes relevant to CVDs. It highlights the potential for innovative therapeutic approaches based on a deeper comprehension of vitamin E's multifaceted effects. However, it also candidly addresses the challenges of translating clinical trial findings into practical applications and emphasizes the importance of considering diverse variables to optimize therapeutic outcomes. In summary, this meticulously conducted study provides a comprehensive examination of vitamin E's potential as a preventive agent against CVDs, recognizing the complexity of the subject and the need for continued research to unlock its full potential in cardiovascular health.

Vitamin Needs and Treatment for Chronic Kidney Disease Patients

This paper summarizes the biochemistry, metabolism, and dietary needs of vitamins in patients with chronic kidney disease (CKD) and kidney transplant recipients. Evidence indicates that the dietary intake, in vivo synthesis, urinary excretion or metabolism of different vitamins may be substantially altered in kidney failure. There are discrepancies in vitamin status assessment depending on whether the assay is functional or measuring the blood vitamin level. Whether vitamin supplements should be routinely prescribed for patients with CKD is controversial. Because low dietary intake and compounds that interfere with vitamin activity are not uncommon in patients with CKD, and water-soluble vitamin supplements appear safe and not costly, the authors recommend that supplements of the water-soluble vitamins should be routinely offered to these individuals. More research is needed to assess vitamin nutrition and function and to determine the daily vitamin needs for all patients with CKD.

Vitamin E supplementation (alone or with other antioxidants) and stroke: a meta-analysis

CONTEXT

A previous study showed that vitamin E is effective in reducing the incidence of myocardial infarction only when it is taken in the absence of other antioxidants. It is unclear if it also reduces the incidence of stroke.

OBJECTIVE

The aim of this meta-analysis is to compare the effect of vitamin E supplementation alone or combined with other antioxidants on the incidence of stroke.

DATA SOURCES

A search was performed in the following databases: PubMed, ISI Web of Science, SCOPUS, and Cochrane Library.

DATA EXTRACTION

Sixteen randomized controlled trials were selected to evaluate the effect of vitamin E supplementation on stroke.

DATA ANALYSIS

The range of vitamin E doses used was 33-800 IU. The follow-up period ranged from 6 months to 9.4 years. Compared with controls, when vitamin E was given alone it did not reduce the incidence of ischemic and hemorrhagic stroke. Conversely, compared with controls, supplementation of vitamin E with other antioxidants reduced ischemic stroke (random effects, RR: 0.91; 95% CI: 0.84-0.99; P = 0.02) but with a significant increase in hemorrhagic stroke (random effects, RR: 1.22; 95% CI: 1.0-1.48; P = 0.04).

CONCLUSIONS

Supplementation with vitamin E alone is not associated with stroke reduction. Instead, supplementation of vitamin E with other antioxidants reduces the incidence of ischemic stroke but increases the risk of hemorrhagic stroke, cancelling any beneficial effect derived. Thus, vitamin E is not recommended in stroke prevention.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022258259.

Renal mitochondrial restoration by gymnemic acid in gentamicin-mediated experimental nephrotoxicity: evidence from serum, kidney and histopathological alterations

Background: Nephrotoxicity refers to the toxigenic impact of compounds and medications on kidney function. There are a variety of drug formulations, and some medicines that may affect renal function in multiple ways via nephrotoxins production. Nephrotoxins are substances that are harmful to the kidneys. Purpose: This investigation examines the renoprotective effect of gymnemic acid (GA) on Wistar rats in gentamicin-induced nephrotoxicity by analyzing serum, kidney, and histopathological markers. Study-design/methods: The current study investigated the protective effect of GA at doses of 20, 40, and 60 mg/kg against gentamicin-induced nephrotoxicity in rats. Vitamin E was administered to compare the antioxidant capacity and efficacy of GA. In addition to the treatment groups, 100 mg/kg of gentamicin was administered intraperitoneal for 14 days. At the end of the study protocol, kidney homogenate, blood, and serum were evaluated biochemically. Serum creatinine, blood urea, glomerular filtration rate (GFR), mitochondrial dysfunctions, inflammatory cytokines, and renal oxidative stress were examined to assess gentamicin-induced nephrotoxicity. In addition, the impact of GA on the above-mentioned nephrotoxic markers were evaluated and further confirmed by histological analysis. Results: This study establishes a correlation between antibiotic use, especifically aminoglycosides and acute renal failure. The research demonstrates the nephrotoxic effects of aminoglycosides, inducing mitochondrial ETC-complex dysfunction, and renal tissue inflammation in experimental rats. GA's antioxidant properties restored renal oxidative stress markers, reducing kidney inflammation and injury. Histopathological analysis revealed a significant reduction in renal injury with GA treatment. Additionally, GA demonstrated greater efficacy than Vitamin E in restoring antioxidant potential and mitochondrial enzymes. Conclusion: Consequently, our findings imply that long-term use of GA may be a suitable therapeutic strategy for reducing aminoglycoside toxicity. The current study suggests GA's potential in treating gentamicin-induced nephrotoxicity and acute renal failure, meriting further investigation using advanced techniques.

Beneficial and adverse effects of vitamin E on the kidney

This article reviews the beneficial and adverse effects of high-dose vitamin E supplementation on the vitamin E status and renal function in human and rodent studies. The high doses of vitamin E, which can cause renal effects, were compared to upper limits of toxicity (UL) as established by various authorities worldwide. In recent mice studies with higher doses of vitamin E, several biomarkers of tissue toxicity and inflammation were found to be significantly elevated. In these biomarker studies, the severity of inflammation and the increased levels of the biomarkers are discussed together with the need to re-evaluate ULs, given the toxic effects of vitamin E on the kidney and emphasizing oxidative stress and inflammation. The controversy in the literature about vitamin E effects on the kidney is mainly caused by the dose-effects relations that do not give a clear view, neither in human nor animals studies. In addition, more recent studies on rodents with new biomarkers of oxidative stress and inflammation give new insights into possible mechanisms. In this review, the controversy is shown and an advice given on the vitamin E supplementation for renal health.

N-Acetylcysteine: more than preventing contrast-induced nephropathy in uremic patients-focus on the antioxidant and anti-inflammatory properties

Oxidative stress (OS) has been recognized as a pathophysiologic mechanism underlying the development and progression of chronic kidney disease (CKD). OS, which results from the disturbance of balance among pro-oxidants and antioxidants favoring the pro-oxidants, is present even in early CKD and increases progressively along with deterioration of kidney function to end-stage kidney disease (ESKD). In ESKD, OS is further exacerbated mainly due to dialysis procedures per se and predisposes to increased cardiovascular morbidity and mortality. Therefore, since OS plays a pivotal role in the pathogenesis and progression of atherosclerosis in uremic patients, several strategies aiming to ameliorate OS in these patients have been proposed. Among those, N-acetylcysteine (NAC), a thiol-containing antioxidant agent, has attracted special attention due to its pleiotropic functions and beneficial effect in various OS-related entities including paracetamol overdose and prevention of contrast-induced nephropathy. In this review, we present the currently available literature on the antioxidant and anti-inflammatory properties of NAC in CKD, including hemodialysis and peritoneal dialysis.

The Effect of Vitamin E Supplementation in Postmenopausal Women-A Systematic Review

Menopause is a physiological change in any woman. Nevertheless, its symptoms could be difficult to accept, and hormone therapy can be sometimes unattractive or contraindicated. Vitamin E components are phytoestrogens, so they are believed to be useful in some indications including menopause. This review aimed to assess the available evidence on the effectiveness of vitamin E in alleviating menopausal symptoms. The Pubmed/MEDLINE, Cochrane Library and Scopus databases were screened. All types of studies that assessed the effectiveness of vitamin E in alleviating menopausal symptoms were included. The PICO question was: "How does vitamin E supplementation affect menopausal symptom occurrence?" The PROSPERO ID number of this review is CRD42022328830. After quality assessment, 16 studies were included in the analysis. The studies were divided into three groups in which the influence of vitamin E on the genital syndrome of menopause, vasomotor symptoms and vascular and metabolic changes were assessed. Vitamin E influences postmenopausal hot flashes, vascular modulation, plasma lipid profile level and vaginal changes. Compared to vitamin E, estrogen administration leads to better clinical effects. Nevertheless, vitamin E might serve as additive to hormone therapy and its alternative in women with contraindications to estrogens. More quality data are necessary to draw final conclusions.

Physiological Mechanisms of Hypertension and Cardiovascular Disease in End-Stage Kidney Disease

PURPOSE OF REVIEW

In this article, we summarize recent advances in understanding hypertension and cardiovascular disease in patients with end-stage kidney disease.

RECENT FINDINGS

Factors such as anemia, valvular and vascular calcification, vasoconstrictors, uremic toxins, hypoglycemia, carbamylated proteins, oxidative stress, and inflammation have all been associated with the progression of cardiovascular disease in end-stage kidney disease but the causality of these mechanisms has not been proven. The high risk of cardiovascular mortality has not improved as in the general population despite many advancements in cardiovascular care over the last two decades. Mechanisms that increase hypertension risk in these patients are centered on the control of extracellular fluid volume; however, over-correction of volume with dialysis can increase risks of intradialytic hypotension and death in these patients. This review presents both recent and classic work that increases our understanding of hypertension and cardiovascular disease in end-stage kidney disease.

Dicarbonyl-Dependent Modification of LDL as a Key Factor of Endothelial Dysfunction and Atherosclerotic Vascular Wall Damage

The review presents evidence that the main damage to the vascular wall occurs not from the action of “oxidized” LDL, which contain hydroperoxy acyls in the phospholipids located in their outer layer, but from the action of LDL particles whose apoprotein B-100 is chemically modified with low molecular weight dicarbonyls, such as malondialdehyde, glyoxal, and methylglyoxal. It has been argued that dicarbonyl-modified LDL, which have the highest cholesterol content, are particularly “atherogenic”. High levels of dicarbonyl-modified LDL have been found to be characteristic of some mutations of apoprotein B-100. Based on the reviewed data, we hypothesized a common molecular mechanism underlying vascular wall damage in atherosclerosis and diabetes mellitus. The important role of oxidatively modified LDL in endothelial dysfunction is discussed in detail. In particular, the role of the interaction of the endothelial receptor LOX-1 with oxidatively modified LDL, which leads to the expression of NADPH oxidase, which in turn generates superoxide anion radical, is discussed. Such hyperproduction of ROS can cause destruction of the glycocalyx, a protective layer of endotheliocytes, and stimulation of apoptosis in these cells. On the whole, the accumulated evidence suggests that carbonyl modification of apoprotein B-100 of LDL is a key factor responsible for vascular wall damage leading to atherogenesis and endothelial dysfunction. Possible ways of pharmacological correction of free radical processes in atherogenesis and diabetogenesis are also discussed.

Liposoluble vitamins A and E in kidney disease

Kidney disease (KD) is characterized by the presence of elevated oxidative stress, and this is postulated as contributing to the high cardiovascular morbidity and mortality in these individuals. Chronic KD (CKD) is related to high grade inflammatory condition and pro-oxidative state that aggravates the progression of the disease by damaging primary podocytes. Liposoluble vitamins (vitamin A and E) are potent dietary antioxidants that have also anti-inflammatory and antiapoptotic functions. Vitamin deficits in CKD patients are a common issue, and multiple causes are related to them: Anorexia, dietary restrictions, food cooking methods, dialysis losses, gastrointestinal malabsorption, etc. The potential benefit of retinoic acid (RA) and α-tocopherol have been described in animal models and in some human clinical trials. This review provides an overview of RA and α tocopherol in KD.

Vitamin E (Alpha-Tocopherol) Metabolism and Nutrition in Chronic Kidney Disease

Vitamin E (alpha-tocopherol) is an essential micronutrient and fat-soluble antioxidant with proposed role in protecting tissues from uncontrolled lipid peroxidation. This vitamin has also important protein function and gene modulation effects. The metabolism of vitamin E depends on hepatic binding proteins that selectively retain food alpha-tocopherol for incorporation into nascent VLDL and tissue distribution together with esterified cholesterol and triglycerides. Chronic kidney disease (CKD) is a condition of oxidative stress and increased lipid peroxidation, that are associated with alterations of alpha-tocopherol metabolism and function. Specific changes have been reported for the levels of its enzymatic metabolites, including both short-chain and long-chain metabolites, the latter being endowed with regulatory functions on enzymatic and gene expression processes important for the metabolism of lipids and xenobiotics detoxification, as well as for the control of immune and inflammatory processes. Vitamin E therapy has been investigated in CKD using both oral vitamin E protocols and vitamin E-coated hemodialyzers, showing promising results in the secondary prevention of cardiovascular disease, as well as of immune and hematological complications. These therapeutic approaches are reviewed in the present article, together with a narrative excursus on the main findings indicating CKD as a condition of relative deficiency and impaired metabolism of vitamin E.

Vitamin E: Where Are We Now in Vascular Diseases?

Vitamin E is one of the most popular fat-soluble vitamins in pathological research and has been under scrutiny since the 1980s as a vital dietary component of food. The antioxidant effect of vitamin E has been widely studied due to its benefits in the prevention of various cardiovascular diseases. In recent years, alternative effects of vitamin E, in terms of anti-inflammatory pathways and gene regulation, have also been of interest to researchers. This review examines the role of dietary vitamin E (α-tocopherol) as an antioxidant and bioactive molecule in promoting vascular health. While the antioxidant effect of vitamin E is well established, knowledge about its capacity as a promising regulatory molecule in the control of the vascular system is limited. The aim of this review is to discuss some of these mechanisms and summarize their role in the prevention of cardiovascular diseases (CVD). Here, we also briefly discuss foods rich in vitamin E, and deliberate some potential toxicological effects of excessive supplemental vitamin E in the body.

Cardiorenal syndrome: long road between kidney and heart

Almost 200 years ago, the first evidence described by Robert Bright (1836) showed the strong interaction between the kidneys and heart and, since then, the scientific community has dedicated itself to better understanding the mechanisms involved in the kidney-heart relationship, known in recent decades as cardiorenal syndrome (CRS). This syndrome includes a wide clinical variety that affects the kidneys and heart, in an acute or chronic manner. Moreover, it is well established in the literature that the immune system, the sympathetic nervous system, the renin-angiotensin-aldosterone, and the oxidative stress actively play a strong role in the cellular and molecular processes present in CRS. More recently, uremic molecules and epigenetic factors have been also shown to be key mediators in the development of syndrome. The present review intends to present the state of the art regarding CRS and to show the paths known, until now, in the long road between the kidneys and heart.

Interventional study with vitamin E in cardiovascular disease and meta-analysis

Cardiovascular disease (CVD) is one of the major causes of morbidity and mortality and atherosclerosis is the common root to most of the CVD. Oxidative stress is one of the most important factors driving atherosclerosis and its complications. Thus, strategies for the prevention and treatment of cardiovascular events had oxidative changes as a potential target. Natural vitamin E consists of a family of eight different compounds, four tocopherols and four tocotrienols. All tocopherols and tocotrienols are potent antioxidants with lipoperoxyl radical-scavenging activities. In addition, α-tocopherol possesses also anti-inflammatory as well as anti-atherothrombotic effects by modulating platelet and clotting system. Experimental and in vitro studies described molecular and cellular signalling pathways regulated by vitamin E antithrombotic and antioxidant properties. While observational studies demonstrated an inverse association between vitamin E serum levels and CVD, interventional trials with vitamin supplements provided negative results. This review focus on the impact of vitamin E in the atherothrombotic process and describes the results of experimental and clinical studies with the caveats related to the interventional trials with vitamin E to prevent CVD.

Vitamin E research: Past, now and future

The early history of vitamin E from its discovery by Herbert M. Evans and Katharine J. S. Bishop in 1922 up to its chemical synthesis by Paul Karrer and coworkers in 1938 and the development of the concept that vitamin E acts as an antioxidant in vivo are recalled. Some more recent results shedding doubt on this hypothesis are reviewed. They comprise influence of vitamin E on enzyme activities, signaling cascades, gene expression and bio-membrane structure. The overall conclusion is that our knowledge of the vitamin's mechanism of action still remains fragmentary. The metabolism of tocopherols and tocotrienols is presented and discussed in respect to bioactivity of the metabolites, interference with drug metabolism and the future design of clinical trials. Some strategies are recommended how to reach the final goal: the identification of the primary vitamin E target(s) and the analysis of the downstream events up to the physiological phenomena.

Do low molecular weight antioxidants contribute to the Protection against oxidative damage? The interrelation between oxidative stress and low molecular weight antioxidants based on data from the MARK-AGE study

A redox steady state is important in maintaining vital cellular functions and is therefore homeostatically controlled by a number of antioxidative agents, the most important of which are enzymes. Oxidative Stress (OS) is associated with (or/and caused by) excessive production of damaging reactive oxygen and/or nitrogen species (ROS, RNS), which play a role in many pathologies. Because OS is a risk factor for many diseases, much effort (and money) is devoted to early diagnosis and treatment of OS. The desired benefit of the "identify (OS) and treat (by low molecular weight antioxidants, LMWA)" approach is to enable selective treatment of patients under OS. The present work aims at gaining understanding of the benefit of the antioxidants based on interrelationship between the concentration of different OS biomarkers and LMWA. Both the concentrations of a variety of biomarkers and of LMWA were previously determined and some analyses have been published by the MARK-AGE team. For the sake of simplicity, we assume that the concentration of an OS biomarker is a linear function of the concentration of a LMWA (if the association is due to causal relationship). A negative slope of this dependence (and sign of the correlation coefficient) can be intuitively expected for an antioxidant, a positive slope indicates that the LMWA is pro-oxidative, whereas extrapolation of the OS biomarker to [LMWA] = 0 is an approximation of the concentration of the OS biomarker in the absence of the LMWA. Using this strategy, we studied the effects of 12 LMWA (including tocopherols, carotenoids and ascorbic acid) on the OS status, as observed with 8 biomarkers of oxidative damage (including malondialdehyde, protein carbonyls, 3-nitrotyrosine). The results of this communication show that in a cross-sectional study the LMWA contribute little to the redox state and that different "antioxidants" are very different, so that single LMWA treatment of OS is not scientifically justified assuming our simple model. In view of the difficulty of quantitating the OS and the very different effects of various LMWA, the use of the "identify and treat" approach is questionable.

Prevalence and predictors of heart failure among patients on maintenance hemodialysis therapy at Muhimbili National Hospital in Tanzania: a cross-sectional study

BACKGROUND

Heart failure among patients on hemodialysis therapy portends poor outcomes. Traditional risk factors like aging, hypertension and diabetes mellitus are relatively common in these patients and may not accurately predict the occurrence of heart failure. Such patients may have other factors that contribute to heart failure. This study aimed to investigate the prevalence and predictors of heart failure among patients on maintenance hemodialysis at Muhimbili National Hospital in Dar es Salaam, Tanzania.

RESULTS

Among 160 patients on maintenance hemodialysis, 49 (30.6%) were female. The mean age of patients was 52.2 ± 13.3 years. Almost all patients had hypertension and 69 (43.1%) had diabetes mellitus. Heart failure was prevalent in 17 (10.6%) patients. On multivariate analysis, presence of angina, intradialytic hypertension, and anemia were independent predictors of heart failure. Patients with heart failure had significantly higher malnutrition inflammation scores and erythropoietin resistance indexes.

CONCLUSIONS

Heart failure among hemodialysis patients correlates with the presence of angina, intradialytic hypertension, and anemia. Patients with heart failure had a greater degree of malnutrition-inflammation complex, and erythropoietin resistance. Patients with these conditions require a thorough cardiac evaluation and appropriate treatment.

Vitamins E and C do not effectively inhibit low density lipoprotein oxidation by ferritin at lysosomal pH

Low density lipoprotein (LDL) might be oxidized by iron in the lysosomes of macrophages in atherosclerotic lesions. We have shown previously that the iron-storage proteinferritin can oxidize LDL at lysosomal pH. We have now investigated the roles of the most important antioxidant contained in LDL, α-tocopherol (the main form of vitamin E) and of ascorbate (vitamin C), a major water-soluble antioxidant, on LDL oxidation by ferritin at lysosomal pH (pH 4.5). We incubated LDL with ferritin at pH 4.5 and 37 °C and measured its oxidation by monitoring the formation of conjugated dienes at 234 n min a spectrophotometer. α-Tocopherol is well known to inhibit LDL oxidation at pH 7.4, but enrichment of LDL with α-tocopherol was unable to inhibit LDL oxidation by ferritin at pH 4.5. Ascorbate had a complex effect on LDL oxidation by ferritin at lysosomal pH and exhibited both antioxidant and pro-oxidant effects. It had no antioxidant effect on partially oxidized LDL, only a pro-oxidant effect. Ascorbate completely inhibited LDL oxidation by copper at pH 7.4 for a long period, but in marked contrast did not inhibit LDL oxidation by copper at lysosomal pH. Dehydroascorbate, the oxidation product of ascorbate, had a pronounced pro-oxidant effect on LDL incubated with ferritin at pH 4.5. The inability of α-tocopherol and ascorbate to effectively inhibit LDL oxidation by ferritin at lysosomal pH might help to explain why the large clinical trials with these vitamins failed to show protection against cardiovascular diseases.

Implications of advanced oxidation protein products and vitamin E in atherosclerosis progression

Introduction

Advanced oxidation protein products (AOPP) are considered as markers of oxidative stress and inflammation, and highly predictive of atherosclerosis. Vitamin E (Vit-E) is a powerful antioxidant, but no consensus on its effectiveness at the level of AOPP or the process of atherosclerosis has been made. Hence this was the aim of the present study.

Material and methods

A longitudinal study was conducted on 205 patients with chronic kidney disease (CKD) and 40 controls. The correlations between AOPP and glomerular filtration rate (GFR) and different biological markers were analyzed. Supra-aortic trunk echo-Doppler was conducted to assess the correlation of AOPP with intima-media thickness. The effects of Vit-E treatment on AOPP levels and atherosclerosis progression were also investigated.

Results

AOPP levels increased in parallel to the alteration of renal functions in CKD patients, compared to the control group (p < 0.05). The mean value of AOPP increased concomitantly with the intima-media thickness (p < 0.05). Furthermore, AOPP mean value was higher in patients with atherosclerotic plaques (p < 0.05) compared to those without plaques. Vit-E treatment stabilized the levels of AOPP but had no effect on the atherosclerotic progression.

Conclusions

AOPP were proved to be effective markers of oxidative stress and their high levels help to predict the progression of atherosclerosis. As a powerful antioxidant, Vit-E stabilized the AOPP levels.

Could Antioxidant Supplementation Delay Progression of Cardiovascular Disease in End-Stage Renal Disease Patients?

In end-stage renal disease patients, the leading causes of mortality are of cardiovascular (CV) origin. The underlying mechanisms are complex, given that sudden heart failure is more common than acute myocardial infarction. A contributing role of oxidative stress is postulated, which is increased even at early stages of chronic kidney disease, is gradually augmented in parallel to progression to endstage renal disease and is further accelerated by renal replacement therapy. Oxidative stress ensues when there is an imbalance between reactive pro-oxidants and physiologically occurring electron donating antioxidant defence systems. During the last decade, a close association of oxidative stress with accelerated atherosclerosis and increased risk for CV and all-cause mortality has been established. Lipid peroxidation has been identified as a trigger for endothelial dysfunction, the first step towards atherogenesis. In order to counteract the deleterious effects of free radicals and thereby ameliorate, or delay, CV disease, exogenous administration of antioxidants has been proposed. Here, we attempt to summarize existing data from studies that test antioxidants for CV protection, such as vitamins E and C, statins, omega-3 fatty acids and N-acetylcysteine.

Implications of oxidative stress in chronic kidney disease: a review on current concepts and therapies

Moderate levels of endogenous reactive oxygen species (ROS) are important for various cellular activities, but high levels lead to toxicity and are associated with various diseases. Levels of ROS are maintained as a balance between oxidants and antioxidants. Accumulating data suggest that oxidative stress is a major factor in deterioration of renal function. In this review, we highlight the possible mechanism by which oxidative stress can lead to chronic kidney disease (CKD). This review also describes therapies that counter the effect of oxidative stress in CKD patients. Numerous factors such as upregulation of genes involved in oxidative phosphorylation and ROS generation, chronic inflammation, vitamin D deficiency, and a compromised antioxidant defense mechanism system cause progressive detrimental effects on renal function that eventually lead to loss of kidney function. Patients with renal dysfunction are highly susceptible to oxidative stress, as risk factors such as diabetes, renal hypertension, dietary restrictions, hemodialysis, and old age predispose them to increased levels of ROS. Biomolecular adducts (DNA, proteins, and lipids) formed due to reaction with ROS can be used to determine oxidative stress levels. Based on the strong correlation between oxidative stress and CKD, reversal of oxidative stress is being explored as a major therapeutic option. Xanthine oxidase inhibitors, dietary antioxidants, and other agents that scavenge free radicals are gaining interest as treatment modalities in CKD patients.

Hypocholesterolemia is a risk factor for reduced systemic vascular resistance reactivity during hemodialysis

Intradialytic hypotension (IDH) is associated with high mortality. Peripheral vascular resistance and circulating blood volume are important factors in IDH; however, the effects of hemodialysis (HD) on vascular resistance in IDH remain unclear. We herein performed a retrospective observational cohort study to investigate changes in and factors related to vascular resistance during HD. A total of 101 HD patients were divided into two groups (Decreased blood pressure (BP) during HD group: N = 19, Nondecreased BP group: N = 82), and cardiac output was measured with electrical velocimetry (AESCLON) for 3 h. The systemic vascular resistance index (SVRI) was significantly decreased in the Decreased BP group, while the cardiac index was similar in both groups. A multivariate regression analysis identified hypocholesterolemia as a predictor of reduced vascular resistance reactivity during HD. Furthermore, a correlation was found between changes in the SVRI and cholesterol levels in patients with a higher Geriatric Nutritional Risk Index (GNRI) but not in those with a lower GNRI. The present results suggest that hypocholesterolemia contributes to reducing systematic vascular resistance reactivity during HD, which is an important predictor of a reduction in BP during HD. The relationship between hypocholesterolemia and vascular resistance may involve mechanisms other than malnutrition.

KLF5 Is Induced by FOXO1 and Causes Oxidative Stress and Diabetic Cardiomyopathy

RATIONALE

Diabetic cardiomyopathy (DbCM) is a major complication in type-1 diabetes, accompanied by altered cardiac energetics, impaired mitochondrial function, and oxidative stress. Previous studies indicate that type-1 diabetes is associated with increased cardiac expression of KLF5 (Krüppel-like factor-5) and PPARα (peroxisome proliferator-activated receptor) that regulate cardiac lipid metabolism.

OBJECTIVE

In this study, we investigated the involvement of KLF5 in DbCM and its transcriptional regulation.

METHODS AND RESULTS

KLF5 mRNA levels were assessed in isolated cardiomyocytes from cardiovascular patients with diabetes and were higher compared with nondiabetic individuals. Analyses in human cells and diabetic mice with cardiomyocyte-specific FOXO1 (Forkhead box protein O1) deletion showed that FOXO1 bound directly on the KLF5 promoter and increased KLF5 expression. Diabetic mice with cardiomyocyte-specific FOXO1 deletion had lower cardiac KLF5 expression and were protected from DbCM. Genetic, pharmacological gain and loss of KLF5 function approaches and AAV (adeno-associated virus)-mediated Klf5 delivery in mice showed that KLF5 induces DbCM. Accordingly, the protective effect of cardiomyocyte FOXO1 ablation in DbCM was abolished when KLF5 expression was rescued. Similarly, constitutive cardiomyocyte-specific KLF5 overexpression caused cardiac dysfunction. KLF5 caused oxidative stress via direct binding on NADPH oxidase (NOX)4 promoter and induction of NOX4 (NADPH oxidase 4) expression. This was accompanied by accumulation of cardiac ceramides. Pharmacological or genetic KLF5 inhibition alleviated superoxide formation, prevented ceramide accumulation, and improved cardiac function in diabetic mice.

CONCLUSIONS

Diabetes-mediated activation of cardiomyocyte FOXO1 increases KLF5 expression, which stimulates NOX4 expression, ceramide accumulation, and causes DbCM.

Antioxidants protect against gingival overgrowth induced by cyclosporine A

OBJECTIVE

We investigated the importance of reactive oxygen species (ROS) on developing gingival overgrowth (GO) and then introduced the antioxidant strategy to prevent, or even reduce GO.

BACKGROUND

Gingival overgrowth is a common side effect of the patients receiving cyclosporine A (CsA), an immune suppressant. Although it has been broadly investigated, the exact pathogenesis of the induced GO is still uncertain.

METHODS

We cultured human primary gingival fibroblasts and used animal model of GO to investigate the ameliorative effects of antioxidants on CsA-induced GO. To examine the CsA-induced oxidative stress, associated genes and protein expression, and the overgrown gingiva of rats by using immunocytochemistry, confocal laser scanning microscopy, real-time PCR, ELISA, gelatin zymography, gingival morphological, and immunohistochemical analysis.

RESULTS

We found for the first time that ROS was responsible for the CsA-induced oxidative stress and TGF-β1 expression in human primary gingival fibroblasts, as well as the GO of rats. The antioxidants (oxidative scavenger of vitamin E and an antioxidative enzyme inducer of hemin) ameliorated CsA-induced pathological and morphological alterations of GO without affected the CsA-suppressed il-2 expression in rats. CsA-induced oxidative stress, HO-1, TGF-β1, and type II EMT were also rescued by antioxidants treatment.

CONCLUSIONS

We concluded that CsA repetitively stimulating the production of ROS is the cause of CsA-GO which is ameliorated by treating antioxidants, including vitamin E and sulforaphane. Furthermore, the immunosuppressive effect of CsA is not interfered by antioxidant treatments in rats. This finding may thus help the clinician devise better prevention strategies in patients susceptible to GO.

Table olives and health: a review

Table olives, a product of olive tree (Olea europaea L.), is an important fermented product of the Mediterranean Diet. Agronomical factors, particularly the cultivar, the ripening stage and the processing method employed are the main factors influencing the nutritional and non-nutritional composition of table olives and their organoleptic properties. The important nutritional value of this product is due to its richness in monounsaturated fat (MUFA), mainly oleic acid, fibre and vitamin E together with the presence of several phytochemicals. Among these, hydroxytyrosol (HT) is the major phenolic compound present in all types of table olives. There is a scarcity of in vitro, in vivo and human studies of table olives. This review focused comprehensively on the nutrients and bioactive compound content as well as the health benefits assigned to table olives. The possible health benefits associated with their consumption are thought to be primarily related to effects of MUFA on cardiovascular health, the antioxidant (AO) capacity of vitamin E and its role in protecting the body from oxidative damage and the anti-inflammatory and AO activities of HT. The influence of multiple factors on composition of the end product and the potential innovation in the production of table olives through the reduction of its final salt content was also discussed.

Anti-allergic effects of vitamin E in allergic diseases: An updated review

Allergic diseases are caused by the immune system's response to innocent antigens called allergens. Recent decades have seen a significant increase in the prevalence of allergic diseases worldwide, which has imposed various socio-economic effects in different countries. Various factors, including genetic factors, industrialization, improved hygiene, and climate change contribute to the development of allergic diseases in many parts of the world. Moreover, changes in lifestyle and diet habits play pivotal roles in the prevalence of allergic diseases. Dietary changes caused by decreased intake of antioxidants such as vitamin E lead to the generation of oxidative stress, which is central to the development of allergic diseases. It has been reported in many articles that oxidative stress diverts immune responses to the cells associated with the pathogenesis of allergic diseases. The aim of this short review was to summarize current knowledge about the anti-allergic properties of vitamin E.

Effects of REDOX in Regulating and Treatment of Metabolic and Inflammatory Cardiovascular Diseases

Reduction oxidation (REDOX) reaction is crucial in life activities, and its dynamic balance is regulated by ROS. Reactive oxygen species (ROS) is associated with a variety of metabolic diseases involving in multiple cellular signalling in pathologic and physiological signal transduction. ROS are the by-products of numerous enzymatic reactions in various cell compartments, including the cytoplasm, cell membrane, endoplasmic reticulum (ER), mitochondria, and peroxisome. ROS signalling is not only involved in normal physiological processes but also causes metabolic dysfunction and maladaptive responses to inflammatory signals, which depends on the cell type or tissue environment. Excess oxidants are able to alter the normal structure and function of DNA, lipids, and proteins, leading to mutations or oxidative damage. Therefore, excessive oxidative stress is usually regarded as the cause of various pathological conditions, such as cancer, neurodegeneration, cardiovascular diseases (CVDs), diabetes, and kidney diseases. Currently, it has been possible to detect diabetes and other cardiac diseases by detecting derivatives accompanied by oxidative stress in vivo as biomarkers, but there is no effective method to treat these diseases. In consequence, it is essential for us to seek new therapy targeting these diseases through understanding the role of ROS signalling in regulating metabolic activity, inflammatory activation, and cardiac diseases related to metabolic dysfunction. In this review, we summarize the current literature on REDOX and its role in the regulation of cardiac metabolism and inflammation, focusing on ROS, local REDOX signalling pathways, and other mechanisms.

Oxidative Stress in ESRD Patients on Dialysis and the Risk of Cardiovascular Diseases

Chronic kidney disease is highly prevalent worldwide. The decline of renal function is associated with inadequate removal of a variety of uremic toxins that exert detrimental effects on cells functioning, thus affecting the cardiovascular system. The occurrence of cardiovascular aberrations in CKD is related to the impact of traditional risk factors and non-traditional CKD-associated risk factors, including anemia; inflammation; oxidative stress; the presence of some uremic toxins; and factors related to the type, frequency of dialysis and the composition of dialysis fluid. Cardiovascular diseases are the most frequent cause for the deaths of patients with all stages of renal failure. The kidney is one of the vital sources of antioxidant enzymes, therefore, the impairment of this organ is associated with decreased levels of these enzymes as well as increased levels of pro-oxidants. Uremic toxins have been shown to play a vital role in the onset of oxidative stress. Hemodialysis itself also enhances oxidative stress. Elevated oxidative stress has been demonstrated to be strictly related to kidney and cardiac damage as it aggravates kidney dysfunction and induces cardiac hypertrophy. Antioxidant therapies may prove to be beneficial since they can decrease oxidative stress, reduce uremic cardiovascular toxicity and improve survival.

Can we Overcome the Predestined Poor Survival of Diabetic Patients? Perspectives from Pre- and Post-Dialysis

Although the survival of diabetic peritoneal dialysis (PD) patients has improved, it is still much worse than the survival of nondiabetic patients. Diabetes has its own risks for cardiovascular disease (CVD), such as increased levels of advanced glycation end-products, carbonyl and oxidative stress, and low-grade inflammation. An independent, graded association has been observed between a reduced glomerular filtration rate and the risk of CVD events in chronic kidney disease (CKD). Both CKD and diabetes synergistically lead to a high risk of CVD. It seems that the poor survival of diabetic PD patients is predestined at the initiation of dialysis because of multiple pre-existing risk factors and comorbid diseases, particularly CVD.

Recently, several trials were successful in improving the survival of patients with diabetic CKD. Tight control of glucose, blood pressure management using angiotensin converting-enzyme inhibitors or angiotensin II receptor blockers, and use of statins, antioxidants, or peroxisome proliferator-activated receptor gamma agonists may improve the survival of diabetic PD patients. However, simple correction of a single CVD risk factor is not likely to be effective. New PD solutions such as those low in glucose degradation products or those with icodextrin may also be effective in reducing the risk of CVD in diabetic PD patients. Therefore, multifactorial interventions—including diet control, early referral, and choice of an optimal PD solution—may improve the survival of diabetic PD patients.

Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis

There are several previous studies on the association of vitamin E with prevention of stroke but the findings remain controversial. We have conducted a systematic review, meta-analysis together with trial sequential analysis of randomised controlled trials to evaluate the effect of vitamin E supplementation versus placebo/no vitamin E on the risk reduction of total, fatal, non-fatal, haemorrhagic and ischaemic stroke. Relevant studies were identified by searching online databases through Medline, PubMed and Cochrane Central Register of Controlled Trials. A total of 18 studies with 148 016 participants were included in the analysis. There was no significant difference in the prevention of total stroke (RR (relative risk)=0.98, 95% CI 0.92-1.04, p=0.57), fatal stroke (RR=0.96, 95% CI 0.77-1.20, p=0.73) and non-fatal stroke (RR=0.96, 95% CI 0.88-1.05, p=0.35). Subgroup analyses were performed under each category (total stroke, fatal stroke and non-fatal stroke) and included the following subgroups (types of prevention, source and dosage of vitamin E and vitamin E alone vs control). The findings in all subgroup analyses were statistically insignificant. In stroke subtypes analysis, vitamin E showed significant risk reduction in ischaemic stroke (RR=0.92, 95% CI 0.85-0.99, p=0.04) but not in haemorrhagic stroke (RR=1.17, 95% CI 0.98-1.39, p=0.08). However, the trial sequential analysis demonstrated that more studies were needed to control random errors. Limitations of this study include the following: trials design may not have provided sufficient power to detect a change in stroke outcomes, participants may have had different lifestyles or health issues, there were a limited number of studies available for subgroup analysis, studies were mostly done in developed countries, and the total sample size for all included studies was insufficient to obtain a meaningful result from meta-analysis. In conclusion, there is still a lack of statistically significant evidence of the effects of vitamin E on the risk reduction of stroke. Nevertheless, vitamin E may offer some benefits in the prevention of ischaemic stroke and additional well-designed randomised controlled trials are needed to arrive at a definitive finding. PROSPERO registration number: CRD42020167827.

Modulation of Lipid Transport and Adipose Tissue Deposition by Small Lipophilic Compounds

Small lipophilic molecules present in foods of plant origin have relevant biological activities at rather low concentrations. Evidence suggests that phytosterols, carotenoids, terpenoids, and tocopherols can interact with different metabolic pathways, exerting beneficial effects against a number of metabolic diseases. These small molecules can modulate triacylglycerol absorption in the intestine and the biosynthesis of chylomicrons, the lipid carriers in the blood. Once in the bloodstream, they can impact lipoprotein clearance from blood, thereby affecting fatty acid release, incorporation into adipocytes and triglyceride reassembling and deposit. Consequently, some of these molecules can regulate pathophysiological processes associated to obesity and its related conditions, such as insulin resistance, metabolic syndrome and type-2 diabetes. The protective capacity of some lipophilic small molecules on oxidative and chemotoxic stress, can modify the expression of key genes in the adaptive cellular response, such as transcription factors, contributing to prevent the inflammatory status of adipose tissue. These small lipophilic compounds can be incorporated into diet as natural parts of food but they can also be employed to supplement other dietary and pharmacologic products as nutraceuticals, exerting protective effects against the development of metabolic diseases in which inflammation is involved. The aim of this review is to summarize the current knowledge of the influence of dietary lipophilic small biomolecules (phytosterols, carotenoids, tocopherols, and triterpenes) on lipid transport, as well as on the effects they may have on pathophysiological metabolic states, related to obesity, insulin resistance and inflammation, providing an evidence-based summary of their main beneficial effects on human health.

Cardiovascular and Metabolic Protection by Vitamin E: A Matter of Treatment Strategy?

Cardiovascular diseases (CVD) cause about 1/3 of global deaths. Therefore, new strategies for the prevention and treatment of cardiovascular events are highly sought-after. Vitamin E is known for significant antioxidative and anti-inflammatory properties, and has been studied in the prevention of CVD, supported by findings that vitamin E deficiency is associated with increased risk of cardiovascular events. However, randomized controlled trials in humans reveal conflicting and ultimately disappointing results regarding the reduction of cardiovascular events with vitamin E supplementation. As we discuss in detail, this outcome is strongly affected by study design, cohort selection, co-morbidities, genetic variations, age, and gender. For effective chronic primary and secondary prevention by vitamin E, oxidative and inflammatory status might not have been sufficiently antagonized. In contrast, acute administration of vitamin E may be more translatable into positive clinical outcomes. In patients with myocardial infarction (MI), which is associated with severe oxidative and inflammatory reactions, decreased plasma levels of vitamin E have been found. The offsetting of this acute vitamin E deficiency via short-term treatment in MI has shown promising results, and, thus, acute medication, rather than chronic supplementation, with vitamin E might revitalize vitamin E therapy and even provide positive clinical outcomes.

KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for nutrition in kidney diseases since 1999. Since the publication of the first KDOQI nutrition guideline, there has been a great accumulation of new evidence regarding the management of nutritional aspects of kidney disease and sophistication in the guidelines process. The 2020 update to the KDOQI Clinical Practice Guideline for Nutrition in CKD was developed as a joint effort with the Academy of Nutrition and Dietetics (Academy). It provides comprehensive up-to-date information on the understanding and care of patients with chronic kidney disease (CKD), especially in terms of their metabolic and nutritional milieu for the practicing clinician and allied health care workers. The guideline was expanded to include not only patients with end-stage kidney disease or advanced CKD, but also patients with stages 1-5 CKD who are not receiving dialysis and patients with a functional kidney transplant. The updated guideline statements focus on 6 primary areas: nutritional assessment, medical nutrition therapy (MNT), dietary protein and energy intake, nutritional supplementation, micronutrients, and electrolytes. The guidelines primarily cover dietary management rather than all possible nutritional interventions. The evidence data and guideline statements were evaluated using Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Cholesterol induced autophagy via IRE1/JNK pathway promotes autophagic cell death in heart tissue

BACKGROUND

Cardiovascular diseases (CVDs), with highest mortality and morbidity rates, are the major cause of death in the world. Due to the limited information on heart tissue changes, mediated by hypercholesterolemia, we planned to investigate molecular mechanisms of endoplasmic reticulum (ER) stress and related cell death in high cholesterol fed rabbit model and possible beneficial effects of α-tocopherol.

METHODS

Molecular changes in rabbit heart tissue and cultured cardiomyocytes (H9c2 cells) were measured by western blotting, qRT-PCR, immunflouresence and flow cytometry experiments. Histological modifications were assessed by light and electron microscopes, while degradation of mitochondria was quantified through confocal microscope.

RESULTS

Feeding rabbits 2% cholesterol diet for 8 weeks and treatment of cultured cardiomyocytes with 10 μg/mL cholesterol for 3 h induced excessive autophagic activity via IRE1/JNK pathway. While no change in ER-associated degradation (ERAD) and apoptotic cell death were determined, electron and confocal microscopy analyses in cholesterol supplemented rabbits revealed significant parameters of autophagic cell death, including cytoplasmic autophagosomes, autolysosomes and organelle loss in juxtanuclear area as well as mitochondria engulfment by autophagosome. Either inhibition of ER stress or JNK in cultured cardiomyocytes or α-tocopherol supplementation in rabbits could counteract the effects of cholesterol.

CONCLUSION

Our findings underline the essential role of hypercholesterolemia in stimulating IRE1/JNK branch of ER stress response which then leads to autophagic cell death in heart tissue. Results also showed α-tocopherol as a promising regulator of autophagic cell death in cardiomyocytes.

Chronic Inflammation in Peritoneal Dialysis: The Search for the Holy Grail?

Mortality and morbidity in chronic kidney disease (CKD) patients are unacceptably high. The annual mortality rate due to cardiovascular disease (CVD) is approximately 9%, which, for the middle-aged person, is at least 10- to 20-fold higher than for the general population. Classic risk factors for CVD are highly prevalent in CKD patients, but they cannot fully account for the excessive rate of CVD in this population. Instead, it has become increasingly clear that nontraditional risk factors, such as systemic inflammation, may play a key role in the development of atherosclerosis. It is well established that inflammatory markers are very powerful predictors of high CVD morbidity and mortality not only in the general population, but particularly in CKD patients. Signs of a sustained low-grade inflammation, such as increased levels of C-reactive protein (CRP), are present in the majority of stage 5 CKD patients, even in patients in clinically stable condition, and they are also commonly observed after the initiation of dialysis therapy. Dialysis therapy — hemodialysis as well as peritoneal dialysis (PD) — may itself contribute to systemic inflammation. Local intraperitoneal inflammation can also occur in patients treated with PD. These local effects may result in a low-grade inflammation, caused by the bioincompatibility of conventional glucose-based dialysis fluids, to intense inflammation associated with peritonitis. Given these circumstances, it is reasonable to hypothesize that strategies aiming to reduce inflammation are potentially important and novel, and could serve to reduce CVD, thereby lowering morbidity and mortality in patients with CKD. In this review we provide information supporting the hypothesis that systemic inflammation is tightly linked to the most common complications of CKD patients, in particular those on PD, and that local inflammation in PD may contribute to various related complications. The aims of this review are to discuss the reasons that make inflammation an attractive target for intervention in CKD, the particular aspects of the inflammation–CVD axis during PD treatment that are likely involved, and possible means for the detection and management of chronic inflammation in PD patients.

Supplemental Vitamins and Minerals for Cardiovascular Disease Prevention and Treatment

PURPOSE OF REVIEW

The objective of this study is to explore the current literature supporting the use oral multivitamins and multi/minerals (OMVMs) for cardiovascular diseases (CVD) treatment and prevention.

RECENT FINDINGS

Data on multivitamins, vitamin C and D, coenzyme Q, calcium, and selenium, has showed no consistent benefit for the prevention of CVD, myocardial infarction, or stroke, nor was there a benefit for all-cause mortality to support their routine supplementation. Folic acid alone and B vitamins with folic acid, B₆ and B₁₂, reduce stroke, whereas niacin and antioxidants are associated with an increased risk of all-cause mortality. Iron deficiency should be avoided and treated if found, but routine supplementation to those without deficiency is not evidence based. Despite the high supplement use by the general public, there is no evidence to support the routine supplementation of oral multivitamins and multi/minerals (OVMN) for CVD prevention or treatment.

The Relationship between Tissue Thioredoxin Reductase Activity and the Psoriasis Area and Severity Index

Introduction:

Psoriasis is an autoimmune disease. The important role of oxidative stress in the pathogenesis of psoriasis had been investigated in different studies. Thioredoxin reductase (TrxR) is a selenocysteine-containing enzyme which is involved in the protection of cells against oxidative stress. Here, we investigated the TrxR activity in skin lesions of psoriatic patients and the possible correlation between this activity and the severity of the disease that was scored based on the Psoriasis Area and Severity Index (PASI).

Materials and Methods:

TrxR activity was determined using TrxR colorimetric method based on the reduction of 5,5'-dithiobis-(2-nitrobenzoic acid) to 5-thio-2-nitrobenzoic acid by TrxR using nicotinamide adenine dinucleotide phosphate in 20 psoriatic patients (11 men and 9 women) aged 38.9 ± 12.6 years. For evaluating the disease severity, PASI score system (mild [PASI <10], moderate [PASI 10–20], or severe [PASI >20]) was utilized that was based on three factors including thickness, erythema, and scaling of lesions.

Results:

Our results revealed that the TrxR activity between different groups of psoriatic patients (according to the PASI score) was statistically significant and it was higher in psoriatic patients with mild disease (correlation coefficient = −0.85).

Conclusion:

These results further strengthen the association between psoriasis and oxidative stress. The increased level of TrxR could be due to the protective effect of this enzyme against the inflammatory process and oxidative stress. Moreover, TrxR could be used as a novel marker for evaluating psoriasis severity.

Inflammation and Oxidative Stress in Chronic Kidney Disease-Potential Therapeutic Role of Minerals, Vitamins and Plant-Derived Metabolites

Chronic kidney disease (CKD) is a debilitating pathology with various causal factors, culminating in end stage renal disease (ESRD) requiring dialysis or kidney transplantation. The progression of CKD is closely associated with systemic inflammation and oxidative stress, which are responsible for the manifestation of numerous complications such as malnutrition, atherosclerosis, coronary artery calcification, heart failure, anemia and mineral and bone disorders, as well as enhanced cardiovascular mortality. In addition to conventional therapy with anti-inflammatory and antioxidative agents, growing evidence has indicated that certain minerals, vitamins and plant-derived metabolites exhibit beneficial effects in these disturbances. In the current work, we review the anti-inflammatory and antioxidant properties of various agents which could be of potential benefit in CKD/ESRD. However, the related studies were limited due to small sample sizes and short-term follow-up in many trials. Therefore, studies of several anti-inflammatory and antioxidant agents with long-term follow-ups are necessary.

Cholesterol Disturbances and the Role of Proper Nutrition in CKD Patients

Chronic kidney disease (CKD) is a widespread disease with increasing prevalence in the modern society. Lipid disturbances are common in this group of patients. In most patients with CKD atherogenic dyslipidemia is observed. Dyslipidemia in patients with renal diseases increases the risk of cardiovascular diseases and it accelerates the progression of chronic kidney disease to its end stage. The amelioration of dyslipidemia and the lowering of oxidative stress, inflammatory processes, insulin sensitivity and remnant lipoproteins levels may lead to the reduction in cardiovascular burden. Nutritional interventions can strengthen the beneficial effect of treatment and they play an important role in the preservation of overall well-being of the patients with CKD since the aim of appropriate diet is to reduce the risk of cardiovascular events, prevent malnutrition, and hamper the progression of kidney disease. The management of dyslipidemia, regardless of the presence of chronic kidney disease, should be initiated by the introduction of therapeutic lifestyle changes. The introduction of diet change was shown to exert beneficial effect on the lipid level lowering that reaches beyond pharmacological therapy. Currently available evidence give the impression that data on dietary interventions in CKD patients is not sufficient to make any clinical practice guidelines and is of low quality.

Oxidative Status before and after Renal Replacement Therapy: Differences between Conventional High Flux Hemodialysis and on-Line Hemodiafiltration

Hemodialysis patients experience high oxidative stress because of systemic inflammation and depletion of antioxidants. Little is known about the global oxidative status during dialysis or whether it is linked to the type of dialysis. We investigated the oxidative status before (pre-) and after (post-) one dialysis session in patients subjected to high-flux dialysis (HFD) or on-line hemodiafiltration (OL-HDF). We analyzed carbonyls, oxidized LDL (oxLDL), 8-hydroxy-2′-deoxyguanosine, and xanthine oxidase (XOD) activity as oxidative markers, and total antioxidant capacity (TAC), catalase, and superoxide dismutase activities as measures of antioxidant defense. Indices of oxidative damage (OxyScore) and antioxidant defense (AntioxyScore) were computed and combined into a global DialysisOxyScore. Both dialysis modalities cleared all markers (p < 0.01) except carbonyls, which were unchanged, and oxLDL, which increased post-dialysis (p < 0.01). OxyScore increased post-dialysis (p < 0.001), whereas AntioxyScore decreased (p < 0.001). XOD and catalase activities decreased post-dialysis after OL-HDF (p < 0.01), and catalase activity was higher after OL-HDF than after HFD (p < 0.05). TAC decreased in both dialysis modalities (p < 0.01), but remained higher in OL-HDF than in HFD post-dialysis (p < 0.05), resulting in a lower overall DialysisOxyScore (p < 0.05). Thus, patients on OL-HDF maintain higher levels of antioxidant defense, which might balance the elevated oxidative stress during dialysis, although further longitudinal studies are needed.