Oxidized LDL and the metabolic syndrome

BCM-7: Opioid-like Peptide with Potential Role in Disease Mechanisms

Bovine milk is an essential supplement due to its rich energy- and nutrient-rich qualities. Caseins constitute the vast majority of the proteins in milk. Among these, β-casein comprises around 37% of all caseins, and it is an important type of casein with several different variants. The A1 and A2 variants of β-casein are the most researched genotypes due to the changes in their composition. It is accepted that the A2 variant is ancestral, while a point mutation in the 67th amino acid created the A1 variant. The digestion derived of both A1 and A2 milk is BCM-7. Digestion of A2 milk in the human intestine also forms BCM-9 peptide molecule. The opioid-like characteristics of BCM-7 are highlighted for their potential triggering effect on several diseases. Most research has been focused on gastrointestinal-related diseases; however other metabolic and nervous system-based diseases are also potentially triggered. By manipulating the mechanisms of these diseases, BCM-7 can induce certain situations, such as conformational changes, reduction in protein activity, and the creation of undesired activity in the biological system. Furthermore, the genotype of casein can also play a role in bone health, such as altering fracture rates, and calcium contents can change the characteristics of dietary products. The context between opioid molecules and BCM-7 points to a potential triggering mechanism for the central nervous system and other metabolic diseases discussed.

The lack of association between different LDL-C levels and oxidized LDL in patients with type 2 diabetes

Background

High concentrations of low-density lipoprotein cholesterol (LDL-C) have been a known risk factor for cardiovascular diseases. Also, the role of oxidized LDL (ox-LDL) in forming atherosclerosis plaque has been proven. However, it has not yet been proven that atherogenic LDL-C by-products like ox-LDL will decrease by keeping the LDL levels at the desired level. This study aimed to examine the relationship between LDL-C and ox-LDL in different LDL-C values in patients with type 2 diabetes (T2D).

Methods

In this cross-sectional study, 347 patients with T2D who received statins were enrolled. LDL-C values were defined into four groups as LDL-C < 55 mg/dL, 55 mg/dL ≤ to <70 mg/dL, 70 mg/dL ≤ to <100 mg/dL and LDL-C ≥ 100 mg/dL. Total cholesterol, triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and ox-LDL were studied in the four defined groups.

Results

Ox-LDL levels were not different among the four groups (p = 0.30). In addition, LDL-C and ox-LDL levels had no significant correlation (r = 0.480, p = 0.376). Additionally, based on this study analysis, ox-LDL levels were significantly correlated with TG levels (r = 0.119, p < 0.05) and TG/HDL ratio (r = 0.390, p < 0.01).

Conclusions

It is concluded that ox-LDL levels were not associated with different LDL-C level categories from <55 mg/dL to >100 mg/dL in patients with T2D. However, the revealed association of ox-LDL with TG level and TG/HDL ratio may be considered in the clinic.

Linoleic Acid: A Narrative Review of the Effects of Increased Intake in the Standard American Diet and Associations with Chronic Disease

The intake of linoleic acid (LA) has increased dramatically in the standard American diet. LA is generally promoted as supporting human health, but there exists controversy regarding whether the amount of LA currently consumed in the standard American diet supports human health. The goal of this narrative review is to explore the mechanisms that underlie the hypothesis that excessive LA intake may harm human health. While LA is considered to be an essential fatty acid and support health when consumed in modest amounts, an excessive intake of LA leads to the formation of oxidized linoleic acid metabolites (OXLAMs), impairments in mitochondrial function through suboptimal cardiolipin composition, and likely contributes to many chronic diseases that became an epidemic in the 20th century, and whose prevalence continues to increase. The standard American diet comprises 14 to 25 times more omega-6 fatty acids than omega-3 fatty acids, with the majority of omega-6 intake coming from LA. As LA consumption increases, the potential for OXLAM formation also increases. OXLAMs have been associated with various illnesses, including cardiovascular disease, cancer, and Alzheimer's disease, among others. Lowering dietary LA intake can help reduce the production and accumulation of OXLAMs implicated in chronic diseases. While there are other problematic components in the standard American diet, the half-life of LA is approximately two years, which means the damage can be far more persistent than other dietary factors, and the impact of reducing excessive LA intake takes time. Therefore, additional research-evaluating approaches to reduce OXLAM formation and cardiolipin derangements following LA consumption are warranted.

Effect of Dietary Berry Supplementation on Antioxidant Biomarkers in Adults with Cardiometabolic Risks: A Systematic Review of Clinical Trials

Cardiometabolic conditions are closely associated with inflammation and oxidative stress. Dietary berries may serve as a beneficial nutrition intervention to address the features of cardiometabolic dysfunction and associated oxidative stress. The high antioxidant status of dietary berries may increase antioxidant capacity and reduce biomarkers of oxidative stress. This systematic review was conducted to investigate these effects of dietary berries. The search was conducted using PubMed, Cochrane Library, Web of Science, and citation searching. Through this search we identified 6309 articles and 54 were included in the review. Each study's risk of bias was assessed using the 2019 Cochrane Methods' Risk of Bias 2 tool. Antioxidant and oxidative stress outcomes were evaluated, and the magnitude of effect was calculated using Cohen's d. A range of effectiveness was reported in the included studies and the quality of the studies differed between the parallel and crossover trials. Considering the inconsistency in reported effectiveness, future investigations are warranted to determine the acute and sustained reductions of oxidative stress biomarkers from dietary berry intake (PROSPERO registration# CRD42022374654).

HDL and LDL have distinct, opposing effects on LPS-induced brain inflammation

Endotoxemia and sepsis induce neuroinflammation and increase the risk of neurodegenerative disorders although the mechanism by which peripheral infection leads to brain inflammation is not well understood. While circulating serum lipoproteins are known immunometabolites with the potential to modulate the acute phase response and cross the blood brain barrier, their contribution to neuroinflammation during systemic infection is unknown. The objective of this study was to elucidate the mechanisms by which lipoprotein subclasses modulate lipopolysaccharide (LPS)-induced neuroinflammation. Adult C57BL/6 mice were divided into 6 treatment groups, including a sterile saline vehicle control group (n = 9), an LPS group (n = 11), a premixed LPS + HDL group (n = 6), a premixed LPS + LDL group (n = 5), a HDL only group (n = 6) and an LDL only group (n = 3). In all cases injections were administered intraperitoneally. LPS was administered at 0.5 mg/kg, and lipoproteins were administered at 20 mg/kg. Behavioural testing and tissue collection was performed 6 h post-injection. The magnitude of peripheral and central inflammation was determined by qPCR of pro-inflammatory genes in fresh liver and brain. Metabolite profiles of liver, plasma and brain were determined by ¹H NMR. Endotoxin concentration in the brain was measured by the Limulus Amoebocyte Lysate (LAL) assay. Co-administration of LPS + HDL exacerbated both peripheral and central inflammation, whilst LPS + LDL attenuated this inflammation. Metabolomic analysis identified several metabolites significantly associated with LPS-induced inflammation, which were partially rescued by LDL, but not HDL. Endotoxin was detected at significantly greater concentrations in the brains of animals that received LPS + HDL compared to LPS + saline, but not those that received LPS + LDL. These results suggest that HDL may promote neuroinflammation through direct shuttling of endotoxin to the brain. In contrast, LDL was shown to have anti-neuroinflammatory properties in this study. Our results indicate that lipoproteins may be useful targets in neuroinflammation and neurodegeneration associated with endotoxemia and sepsis.

Biomarkers of oxidative stress and reproductive complications

Oxidative stress is the result of an imbalance between the formation of reactive oxygen species (ROS) and the levels of enzymatic and non-enzymatic antioxidants. The assessment of biological redox status is performed by the use of oxidative stress biomarkers. An oxidative stress biomarker is defined as any physical structure or process or chemical compound that can be assessed in a living being (in vivo) or in solid or fluid parts thereof (in vitro), the determination of which is a reproducible and reliable indicator of oxidative stress. The use of oxidative stress biomarkers allows early identification of the risk of developing diseases associated with this process and also opens up possibilities for new treatments. At the end of the last century, interest in oxidative stress biomarkers began to grow, due to evidence of the association between the generation of free radicals and various pathologies. Up to now, a significant number of studies have been carried out to identify and apply different oxidative stress biomarkers in clinical practice. Among the most important oxidative stress biomarkers, it can be mentioned the products of oxidative modifications of lipids, proteins, nucleic acids, and uric acid as well as the measurement of the total antioxidant capacity of fluids in the human body. In this review, we aim to present recent advances and current knowledge on the main biomarkers of oxidative stress, including the discovery of new biomarkers, with emphasis on the various reproductive complications associated with variations in oxidative stress levels.

The Impact of Aerobic Exercise on HDL Quantity and Quality: A Narrative Review

High-density lipoproteins comprise roughly 25-30% of the circulating proteins involved in the transport of lipids in circulation. These particles differ in size and lipid composition. Recent evidence suggests that the quality of HDL particles (which depends on shape, size and the composition of proteins and lipids determining HDL functionality) may be more important than their quantity. The functionality of HDL is mirrored by its cholesterol efflux activity, as well as its antioxidant (including the protection of LDL against oxidation), anti-inflammatory and antithrombotic properties. The results of many studies and meta-analyses imply the beneficial impact of aerobic exercise on HDL-C levels. Physical activity was found to be usually associated with an increase in HDL cholesterol and a decrease in LDL cholesterol and triglycerides. Exercise, apart from inducing quantitative alterations in serum lipids, exerts a beneficial impact on HDL particle maturation, composition and functionality. The Physical Activity Guidelines Advisory Committee Report underlined the importance of establishing a program recommending exercises that enable attainment of maximal advantage at the lowest level of risk. The aim of this manuscript is to review the impact of different types of aerobic exercise (various intensities and durations) on the level and quality of HDL.

The Potential Role of Connexins in the Pathogenesis of Atherosclerosis

Connexins (Cx) are members of a protein family which enable extracellular and intercellular communication through hemichannels and gap junctions (GJ), respectively. Cx take part in transporting important cell-cell messengers such as 3',5'-cyclic adenosine monophosphate (cAMP), adenosine triphosphate (ATP), and inositol 1,4,5-trisphosphate (IP3), among others. Therefore, they play a significant role in regulating cell homeostasis, proliferation, and differentiation. Alterations in Cx distribution, degradation, and post-translational modifications have been correlated with cancers, as well as cardiovascular and neurological diseases. Depending on the isoform, Cx have been shown either to promote or suppress the development of atherosclerosis, a progressive inflammatory disease affecting large and medium-sized arteries. Cx might contribute to the progression of the disease by enhancing endothelial dysfunction, monocyte recruitment, vascular smooth muscle cell (VSMC) activation, or by inhibiting VSMC autophagy. Inhibition or modulation of the expression of specific isoforms could suppress atherosclerotic plaque formation and diminish pro-inflammatory conditions. A better understanding of the complexity of atherosclerosis pathophysiology linked with Cx could result in developing novel therapeutic strategies. This review aims to present the role of Cx in the pathogenesis of atherosclerosis and discusses whether they can become novel therapeutic targets.

The Current Status of Research on High-Density Lipoproteins (HDL): A Paradigm Shift from HDL Quantity to HDL Quality and HDL Functionality

The quantity of high-density lipoproteins (HDL) is represented as the serum HDL-C concentration (mg/dL), while the HDL quality manifests as the diverse features of protein and lipid content, extent of oxidation, and extent of glycation. The HDL functionality represents several performance metrics of HDL, such as antioxidant, anti-inflammatory, and cholesterol efflux activities. The quantity and quality of HDL can change during one’s lifetime, depending on infection, disease, and lifestyle, such as dietary habits, exercise, and smoking. The quantity of HDL can change according to age and gender, such as puberty, middle-aged symptoms, climacteric, and the menopause. HDL-C can decrease during disease states, such as acute infection, chronic inflammation, and autoimmune disease, while it can be increased by regular aerobic exercise and healthy food consumption. Generally, high HDL-C at the normal level is associated with good HDL quality and functionality. Nevertheless, high HDL quantity is not always accompanied by good HDL quality or functionality. The HDL quality concerns the morphology of the HDL, such as particle size, shape, and number. The HDL quality also depends on the composition of the HDL, such as apolipoproteins (apoA-I, apoA-II, apoC-III, serum amyloid A, and α-synuclein), cholesterol, and triglyceride. The HDL quality is also associated with the extent of HDL modification, such as glycation and oxidation, resulting in the multimerization of apoA-I, and the aggregation leads to amyloidogenesis. The HDL quality frequently determines the HDL functionality, which depends on the attached antioxidant enzyme activity, such as the paraoxonase and cholesterol efflux activity. Conventional HDL functionality is regression, the removal of cholesterol from atherosclerotic lesions, and the removal of oxidized species in low-density lipoproteins (LDL). Recently, HDL functionality was reported to expand the removal of β-amyloid plaque and inhibit α-synuclein aggregation in the brain to attenuate Alzheimer’s disease and Parkinson’s disease, respectively. More recently, HDL functionality has been associated with the susceptibility and recovery ability of coronavirus disease 2019 (COVID-19) by inhibiting the activity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The appearance of dysfunctional HDL is frequently associated with many acute infectious diseases and chronic aging-related diseases. An HDL can be a suitable biomarker to diagnose many diseases and their progression by monitoring the changes in its quantity and quality in terms of the antioxidant and anti-inflammatory abilities. An HDL can be a protein drug used for the removal of plaque and as a delivery vehicle for non-soluble drugs and genes. A dysfunctional HDL has poor HDL quality, such as a lower apoA-I content, lower antioxidant ability, smaller size, and ambiguous shape. The current review analyzes the recent advances in HDL quantity, quality, and functionality, depending on the health and disease state during one’s lifetime.

Effects of Anthocyanin-rich Berries on the Risk of Metabolic Syndrome: A Systematic Review and Meta-analysis

OBJECTIVE: Metabolic syndrome (MetS) can lead to fatal complications, including cardiovascular disease. Emerging evidence suggests has emerged that increased fruit and vegetable intake and decreased intake of saturated fats, simple sugars, and processed foods can improve cardiovascular health. Anthocyanins (color pigments) have anti-inflammatory and antioxidant capacities but are of low bioavailability. In this systematic review and metaanalysis, we investigate the possible beneficial effects of the intake of berries high in anthocyanins on MetS risk factors. We also investigate the influences of high-density lipoprotein (HDL), lowdensity lipoprotein (LDL), triglycerides (TG), and total cholesterol (TC). METHODS: We identified 2,274 articles from PUBMED and EMBASE following a search input designed to include studies of interest of these, 21 met inclusion criteria. RESULTS: The studies showed an overall reduction in low-density lipoprotein (p=0.04). Increases in HDL were found with cranberry and freeze-dried berry intake during a 4-6-week intervention. No statistically significant findings were detected for fasting glucose, Hb1Ac, insulin levels, blood pressure, oxidized LDL (OX-LDL), BMI, and overall HDL. CONCLUSIONS: We conclude from this systematic review and meta-analysis that increased berry intake improves MetS key risk factors and reduces the risk of cardiovascular disease. Pronounced effects were apparent for concentrated berry products, such as freeze-dried strawberries.

Effect of saffron supplementation on oxidative stress parameters: A systematic review and meta-analysis of randomized placebo-controlled trials

Oxidative stress (OS), the absence of equilibrium between prooxidants and antioxidants in the body, has been shown to play a pivotal role in the initiation and progression of many diseases. Saffron has been noted for its antioxidant capacity and can be used to improve OS parameters in unhealthy patients. Our aim was to evaluate the efficacy of saffron supplementation on OS parameters in unhealthy patients in randomized controlled trials (RCTs). We searched Medline, EMBASE, Cochrane CENTRAL, Scopus, and Web of Science without language restrictions for RCTs up until April 2021. Studies were included if they compared any form of saffron supplementation to placebo or no supplementation on OS parameters in unhealthy patients. Using a random-effects model with calculated standardized mean difference (SMD) and 95% confidence intervals (CI), we quantitatively synthesized the data. Heterogeneity was assessed using Cochrane's I 2 values. Ten randomized controlled trials were eligible for this review. Seven were included in the meta-analysis and indicated an association between saffron intake and a statistically significant decrease in malondialdehyde (MDA) levels (SMD: -0.40; 95% CI: -0.63, -0.17; I 2 = 32.6%) and a significant increase in total antioxidant capacity (TAC, SMD: 0.24; 95% CI: 0.05, 0.42; I 2 = 00.0%). Saffron intake was shown to significantly impact MDA and TAC, indicating its beneficial properties in improving OS in unhealthy patients. However, additional RCTs are required to evaluate the effect on other OS parameters.

Smoking and Neuropsychiatric Disease-Associations and Underlying Mechanisms

Despite extensive efforts to combat cigarette smoking/tobacco use, it still remains a leading cause of global morbidity and mortality, killing more than eight million people each year. While tobacco smoking is a major risk factor for non-communicable diseases related to the four main groups—cardiovascular disease, cancer, chronic lung disease, and diabetes—its impact on neuropsychiatric risk is rather elusive. The aim of this review article is to emphasize the importance of smoking as a potential risk factor for neuropsychiatric disease and to identify central pathophysiological mechanisms that may contribute to this relationship. There is strong evidence from epidemiological and experimental studies indicating that smoking may increase the risk of various neuropsychiatric diseases, such as dementia/cognitive decline, schizophrenia/psychosis, depression, anxiety disorder, and suicidal behavior induced by structural and functional alterations of the central nervous system, mainly centered on inflammatory and oxidative stress pathways. From a public health perspective, preventive measures and policies designed to counteract the global epidemic of smoking should necessarily include warnings and actions that address the risk of neuropsychiatric disease.

The role of oxidant-antioxidant markers and resistin in metabolic syndrome elderly individuals

In elderly, hormones and oxidant-antioxidant interplay are suggested to mediate biochemical balance between adipose tissue to other tissues. Thus the study attempts to explore metabolic traits, plasma resistin, and oxidant-antioxidant markers in metabolic syndrome (MetS) in comparison to non-metabolic syndrome (non-MetS) elderly individuals. A total of 541 healthy elderly Caucasians, with no acute and/or chronic disorders were invited. After taking into account inclusion/exclusion criteria's the MetS was defined as the presence of three out of five abnormal findings and allowed to divided groups into: non-metabolic syndrome, non-MetS (n = 25, median age 69.0 years), and newly diagnosed MetS (n = 29; median age 70.5 years) individuals. Glucose, plasma lipids, resistin (Res), thiobarbituric acid-reacting substances (TBARS), total antioxidant status (TAS), and Cu,Zn-superoxide dismutase (SOD-1) were measured. The MetS had higher resistin than non-MetS (p < 0.04). The linear correlation (all at p < 0.05) showed correlation for Res&triacylglycerols (R = 0.44), and for Res&diastolic blood pressure (R = -0.58) and for SOD-1&fasting glucose (R = -0.34) in MetS, while in the non-MetS group fasting glucose correlates with Res (R = 0.58) and with TAS (R = -0.43). The multiple regression analysis (alone and in combination) showed that independently from other factors resistin correlated positively with fasting glucose (β = 0.37; R = 0.58; R2 = 0.23; p < 0.01) in all investigated elderly participants. In the MetS resistin correlated negatively with diastolic blood pressure (β = -0.68; R = 0.80; R2 = 0.53; p = 0.0004) moreover in that group TAS correlated negatively with HDL-C (β = -0.71; R = 0.72; R2 = 0.37; p = 0.01). While age correlated negatively with systolic blood pressure (β = -0.60; R = 0.62; R2 = 0.14; p = 0.03) independently from other factors in the non-MetS group. Various metabolic factors contribute to maintain serum resistin and oxidant-antioxidant balance in the elderly people in the presence or absence of MetS. Resistin may serve as a predictor of MetS in the elderly, while strong antioxidant defense interactions in older individuals may indicate good health.

Telomere Length and Oxidative Stress and Its Relation with Metabolic Syndrome Components in the Aging

Simple Summary

A link between telomere length and some age-related diseases has been identified, including metabolic syndrome. So far, there is no mechanism to explain the origin or cause of telomere shortening in this syndrome; however, oxidative stress is a constant factor. Therefore, we reviewed scientific evidence that supported the association between oxidative stress and telomere length dynamics, also examining how each of the metabolic syndrome components individually affects the length. In this regard, there is strong scientific evidence that an increase in the number of metabolic syndrome components is associated with a shorter telomere length, oxidative damage at the lipid and DNA level, and inflammation, as well as its other components, such as obesity, hyperglycemia, and hypertension, while for dyslipidemia, there is a little more discrepancy. The difficulty for the correct treatment of metabolic syndrome lies in its multifactorial nature. Hence, there is a need to carry out more studies on healthy lifestyles during aging to prevent and reduce oxidative damage and telomere wear during aging, and consequently the progression of chronic degenerative diseases, thus improving the living conditions of older people.

Abstract

A great amount of scientific evidence supports that Oxidative Stress (OxS) can contribute to telomeric attrition and also plays an important role in the development of certain age-related diseases, among them the metabolic syndrome (MetS), which is characterised by clinical and biochemical alterations such as obesity, dyslipidaemia, arterial hypertension, hyperglycaemia, and insulin resistance, all of which are considered as risk factors for type 2 diabetes mellitus (T2DM) and cardiovascular diseases, which are associated in turn with an increase of OxS. In this sense, we review scientific evidence that supports the association between OxS with telomere length (TL) dynamics and the relationship with MetS components in aging. It was analysed whether each MetS component affects the telomere length separately or if they all affect it together. Likewise, this review provides a summary of the structure and function of telomeres and telomerase, the mechanisms of telomeric DNA repair, how telomere length may influence the fate of cells or be linked to inflammation and the development of age-related diseases, and finally, how the lifestyles can affect telomere length.

The Impact of Oxidative Stress in Human Pathology: Focus on Gastrointestinal Disorders

Accumulating evidence shows that oxidative stress plays an essential role in the pathogenesis and progression of many diseases. The imbalance between the production of reactive oxygen species (ROS) and the antioxidant systems has been extensively studied in pulmonary, neurodegenerative cardiovascular disorders; however, its contribution is still debated in gastrointestinal disorders. Evidence suggests that oxidative stress affects gastrointestinal motility in obesity, and post-infectious disorders by favoring the smooth muscle phenotypic switch toward a synthetic phenotype. The aim of this review is to gain insight into the role played by oxidative stress in gastrointestinal pathologies (GIT), and the involvement of ROS in the signaling underlying the muscular alterations of the gastrointestinal tract (GIT). In addition, potential therapeutic strategies based on the use of antioxidants for the treatment of inflammatory gastrointestinal diseases are reviewed and discussed. Although substantial progress has been made in identifying new techniques capable of assessing the presence of oxidative stress in humans, the biochemical-molecular mechanisms underlying GIT mucosal disorders are not yet well defined. Therefore, further studies are needed to clarify the mechanisms through which oxidative stress-related signaling can contribute to the alteration of the GIT mucosa in order to devise effective preventive and curative therapeutic strategies

The Influence of a Conjugated Pneumococcal Vaccination on Plasma Antibody Levels against Oxidized Low-Density Lipoprotein in Metabolic Disease Patients: A Single-Arm Pilot Clinical Trial

As a mediator between lipid metabolism dysfunction, oxidative stress and inflammation, oxidized low-density lipoprotein (oxLDL) is a promising therapeutical target in a wide range of metabolic diseases. In mice, pneumococcal immunization increases anti-phosphorylcholine and oxLDL antibody levels, and reduces atherosclerosis, non-alcoholic steatohepatitis and Niemann–Pick disease burden. These findings suggest that pneumococcal vaccination may be a useful preventive and therapeutical strategy in metabolic disease patients. In this pilot clinical trial, our aim was to determine whether the administration of a pneumococcal vaccine increases anti-phosphorylcholine and anti-oxLDL antibody levels in metabolic disease patients. The following patients were enrolled: four patients with familial partial lipodystrophy (all women, mean age 32 years old); three familial hypercholesterolemia patients (one girl, two boys; mean age 13 years); and two Niemann–Pick type B (NP-B) patients (two men, mean age 37.5 years old). Participants received one active dose of a 13-valent conjugated pneumococcal vaccine (Prevenar 13) and were followed-up for four weeks. Four weeks after Prevenar 13 vaccination, no differences were observed in patients’ levels of anti-oxLDL IgM or IgG antibodies. In addition, we observed a reduction in anti-phosphorylcholine (anti-PC) IgM antibody levels, whereas no differences were observed in anti-PC IgG antibody titers. These findings indicate that Prevenar 13 vaccination does not induce an immune response against oxLDL in patients with metabolic diseases. Therefore, Prevenar 13 is not suited to target the metabolic disruptor and pro-inflammatory mediator oxLDL in patients.

Effects of Modified Low-Density Lipoproteins and Fenofibrate on an Outer Blood-Retina Barrier Model: Implications for Diabetic Retinopathy

Purpose: There is a lack of treatment for early diabetic retinopathy (DR), including blood-retina barrier (BRB) breakdown. The robust clinical benefit of fenofibrate in DR provides an opportunity to explore disease mechanisms and therapeutic targets. We have previously found that modified lipoproteins contribute to DR and that fenofibrate protects the inner BRB. We now investigate (1) whether modified lipoproteins elicit outer BRB injury and (2) whether fenofibrate may alleviate such damage.

Methods: Human retinal pigment epithelium ARPE-19 cells were cultured in semipermeable transwells to establish a monolayer barrier and then exposed to heavily oxidized, glycated low-density lipoprotein (HOG-LDL, 25–300 mg/L, up to 24 h) versus native (N)-LDL. Transepithelial electric resistance (TEER) and FITC-dextran permeability were measured. The effects of fenofibrate, its active metabolite fenofibric acid, and other peroxisome proliferator-activated receptor (PPARα) agonists (gemfibrozil, bezafibrate, and WY14643) were evaluated, with and without the PPARα antagonist GW6471 or the adenosine monophosphate-activated protein kinase (AMPK) inhibitor Compound C.

Results: HOG-LDL induced concentration- and time-dependent barrier impairment, decreasing TEER and increasing dextran leakage, effects that were amplified by high glucose. Fenofibric acid, but not fenofibrate, gemfibrozil, bezafibrate, or WY14643, attenuated barrier impairment. This effect was reversed significantly by Compound C, but not by GW6471.

Conclusions: Modified lipoproteins elicited outer BRB injury in an experimental model, which was reduced by fenofibric acid through a PPARα-independent, AMPK-mediated mechanism. These findings suggest a protective role of fenofibric acid on the outer BRB in diabetic retina.

Effects of a Vegetarian Diet on Cardiometabolic Risk Factors, Gut Microbiota, and Plasma Metabolome in Subjects With Ischemic Heart Disease: A Randomized, Crossover Study

Background A vegetarian diet (VD) may reduce future cardiovascular risk in patients with ischemic heart disease. Methods and Results A randomized crossover study was conducted in subjects with ischemic heart disease, assigned to 4-week intervention periods of isocaloric VD and meat diet (MD) with individually designed diet plans, separated by a 4-week washout period. The primary outcome was difference in oxidized low-density lipoprotein cholesterol (LDL-C) between diets. Secondary outcomes were differences in cardiometabolic risk factors, quality of life, gut microbiota, fecal short-chain and branched-chain fatty acids, and plasma metabolome. Of 150 eligible patients, 31 (21%) agreed to participate, and 27 (87%) participants completed the study. Mean oxidized LDL-C (-2.73 U/L), total cholesterol (-5.03 mg/dL), LDL-C (-3.87 mg/dL), and body weight (-0.67 kg) were significantly lower with the VD than with the MD. Differences between VD and MD were observed in the relative abundance of several microbe genera within the families Ruminococcaceae, Lachnospiraceae, and Akkermansiaceae. Plasma metabolites, including l-carnitine, acylcarnitine metabolites, and phospholipids, differed in subjects consuming VD and MD. The effect on oxidized LDL-C in response to the VD was associated with a baseline gut microbiota composition dominated by several genera of Ruminococcaceae. Conclusions The VD in conjunction with optimal medical therapy reduced levels of oxidized LDL-C, improved cardiometabolic risk factors, and altered the relative abundance of gut microbes and plasma metabolites in patients with ischemic heart disease. Our results suggest that composition of the gut microbiota at baseline may be related to the reduction of oxidized LDL-C observed with the VD. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT02942628.

Antioxidants and Oxidative Stress in Children: Influence of Puberty and Metabolically Unhealthy Status

Oxidative stress could help explain the relationship between childhood obesity and a metabolically unhealthy (MU) status. Moreover, puberty could also influence this relationship, since it entails physiological cardiometabolic changes. We aimed to evaluate plasma antioxidants and oxidative stress biomarkers in MU and metabolically healthy (MH) prepubertal and pubertal children and their associations with pro-inflammatory and endothelial damage biomarkers, taking puberty into account. A total of 1444 Spanish children aged 3-17 years (48.9% males, 66% prepubertal, 47.1% with obesity) were recruited. Blood pressure, anthropometric and biochemical parameters were measured, and children were categorized as having a MU or MH status according to risk factors. Retinol, carotenes, tocopherols, total antioxidant capacity (TAC), oxidized low-density lipoprotein and selected pro-inflammatory and endothelial damage biomarkers were analyzed. General linear models adjusted for age, sex, recruitment center and body mass index, partial correlations and stepwise linear regressions were performed. Lower carotenes and tocopherols levels were found in MU than in MH children. Plasma TAC was lower in prepubertal and higher in pubertal children with obesity compared to normal-weight children. Antioxidants and oxidative stress biomarkers showed novel associations with several pro-inflammatory and endothelial damage biomarkers, with pubertal differences, supporting the importance of considering both the antioxidant and oxidative stress status and puberty in the prevention of metabolic diseases in childhood.

Oxidized LDL induces procoagulant profiles by increasing lysophosphatidylcholine levels, lysophosphatidylethanolamine levels, and Lp-PLA2 activity in borderline hypercholesterolemia

BACKGROUND AND AIMS

The increased risk of cardiovascular disease under hypercholesterolemia is due to associations between oxidized low-density lipoprotein (ox-LDL) and lipoprotein-associated phospholipase A₂ (Lp-PLA₂) and between ox-LDL and coagulant profiles. We investigated the impact of different ox-LDL levels on coagulation time and plasma metabolomes in subjects with borderline hypercholesterolemia.

METHODS AND RESULTS

One hundred thirty-one subjects with borderline hypercholesterolemia (serum cholesterol ≥200 mg/dL) were divided into low ox-LDL (n = 66) and high ox-LDL (n = 65) groups. After adjusting for confounding factors, the high ox-LDL group exhibited a significantly decreased activated partial thromboplastin time (aPTT) and prothrombin time (PT) and increased Lp-PLA₂ activity. Compared to the low ox-LDL group, the high ox-LDL group exhibited significantly increased intensities of 17 lysophosphatidylcholines (lysoPCs) and 7 lysophosphatidylethanolamines (lysoPEs). Ox-LDL was inversely correlated with aPTT and PT and positively correlated with Lp-PLA₂ activity. Positive correlations were also found among ox-LDL, Lp-PLA₂ activity, lysoPCs, and lysoPEs. LysoPCs and lysoPEs were inversely correlated with PT and aPTT. The identified plasma metabolites, including amino acids, fatty acid amides, acylcarnitines, and lysophospholipids, were significantly upregulated in the high ox-LDL group.

CONCLUSION

High ox-LDL levels may be involved in the development of a procoagulant state in subjects with borderline hypercholesterolemia by increasing Lp-PLA₂ activity and lysoPC and lysoPE levels.

Circulating levels of oxidized low-density lipoprotein in patients with obstructive sleep apnea: a systematic review and meta-analysis

BACKGROUND

Obstructive sleep apnea (OSA) is associated with an increased risk of developing atherosclerotic cardiovascular disease (ASCVD). Patients with OSA have increased levels of oxidative stress and several studies have shown higher levels of oxidative stress markers. Oxidized-LDL (Ox-LDL) is an important risk factor for ASCVD and a number of studies have measured its levels in patients with OSA, though results from these studies are conflicting. This meta-analysis aimed to reassess circulating levels of Ox-LDL in patients with OSA in comparison with controls.

METHODS

Studies evaluating Ox-LDL levels in patients with OSA and controls were explored in databases of PubMed, EMBASE, Scopus, and Web of Science. Two authors independently performed the search from January 1990 to February 2019. Two authors independently screened the studies according to title, abstract, and full text. In addition, the Newcastle-Ottawa Quality Assessment Scale was utilized to evaluate the quality of the studies. The impact of OSA on Ox-LDL levels was determined using the random effects model.

RESULTS

Of 195 articles retrieved, 98 were duplicates, 49 were excluded by title, 20 excluded by abstract, and 22 by full texts. Six eligible studies were included in the meta-analysis. Pooled analysis demonstrated that Ox-LDL increased in patients with OSA compared with controls. In addition, subgroup analysis revealed that studies matching age or BMI between OSA patients and controls showed no significant difference between patients with OSA and healthy controls, while unmatched studies had higher levels of Ox-LDL in patients with OSA in comparison with controls.

CONCLUSION

This study demonstrated higher circulating concentrations of Ox-LDL in patients with OSA. However, no significant difference was found in studies in which patients and controls were matched for age and BMI, suggesting the involvement of these two confounding factors as a cause for elevated concentrations of circulating Ox-LDL in patients with OSA.

Protection of natural antioxidants against low-density lipoprotein oxidation

This chapter reports essential information about the protective action of antioxidants against LDL oxidation. The activity of individual compounds (tocopherols, vitamin C, phenolic compounds) as well as extracts obtained from plant material (cereals, fruits, legumes, nuts, mushrooms, by-products of food industry) is reported. The structure-antioxidant activity relationship of phenolic compounds is discussed. This article summarizes the findings to date of both in vitro and in vivo studies using foods or phenolic extracts isolated from foodstuffs at inhibiting the incidence of LDL oxidation. This chapter summarizes also the reportings to date of in vivo studies using foods or beverages at inhibiting the incidence of LDL oxidation.

Role of Heparin-Binding Epidermal Growth Factor-Like Growth Factor in Oxidative Stress-Associated Metabolic Diseases

Heparin-binding EGF-like growth factor (HB-EGF) is an EGF family member that interacts with epidermal growth factor receptor (EGFR) and ERBB4. Since HB-EGF was first identified as a novel growth factor secreted from a human macrophage cell line, numerous pathological and physiological functions related to cell proliferation, migration, and inflammation have been reported. Notably, the expression of HB-EGF is sensitively upregulated by oxidative stress in the endothelial cells and functions for auto- and paracrine-EGFR signaling. Overnutrition and obesity cause elevation of HB-EGF expression and EGFR signaling in the hepatic and vascular systems. Modulations of HB-EGF signaling showed a series of protections against phenotypes related to metabolic syndrome and advanced metabolic diseases, suggesting HB-EGF as a potential target against metabolic diseases.

Serum malondialdehyde-modified low-density lipoprotein levels on admission predict prognosis in patients with acute coronary syndrome undergoing percutaneous coronary intervention

BACKGROUND

Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is a predictive marker of cardiovascular events in patients with stable angina pectoris. However, little is known about this marker in patients with acute coronary syndrome (ACS). We investigated the prognostic relevance of MDA-LDL to cardiovascular outcomes in patients with ACS.

METHODS

A total of 370 consecutive patients with ACS who underwent primary percutaneous coronary intervention (PCI) were enrolled from October 2009 to September 2014 at Mitoyo General Hospital. Serum MDA-LDL levels were measured at admission. The patients were divided into three tertile groups according to serum MDA-LDL levels. The primary outcomes were cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, revascularization, and heart failure requiring hospital admission.

RESULTS

MDA-LDL levels in patients with acute myocardial infarction were significantly greater than those in patients with unstable angina pectoris (mean±standard deviation: 133±48U/L vs. 157±69U/L, p=0.001). During follow-up [472 (195-920) days], 82 (22%) events occurred. Kaplan-Meier analysis showed that patients in the highest MDA-LDL tertile had the worst prognosis (log-rank, p<0.001). Cox regression analysis showed that serum MDA-LDL levels were an independent predictor of cardiovascular events after PCI in patients with ACS, even after adjustment for age, sex, body mass index, conventional cardiovascular risk factors, other lipid biomarkers, statin use on admission, cardiac biomarkers, and presence or absence of multivessel disease (hazard ratio: 1.80 per 1 standard deviation U/L increase, 95% confidence interval: 1.07-3.16, p=0.027).

CONCLUSION

Serum MDA-LDL levels on admission are a significant prognostic marker in patients with ACS who undergo successful PCI.

Pro-oncogenic action of LOX-1 and its splice variant LOX-1Δ4 in breast cancer phenotypes

The identification of new predictive biomarkers and therapeutic target for tailored therapy in breast cancer onset and progression is an interesting challenge. OLR-1 gene encodes the cell membrane receptor LOX-1 (lectin-like oxidized low-density lipoprotein receptor). We have recently identified a novel alternative OLR-1 isoform, LOX-1Δ4, whose expression and functions are still not clarified. In the present paper, we demonstrated that LOX-1 is overexpressed in 70% of human breast cancer (n = 47) and positively correlated to the tumor stage and grade (p < 0.01). Observations on LOX-1 and its splice variant Δ4 pointed out a different expression pattern correlated to breast cancer phenotypes. Overexpressing LOX-1 and LOX-1Δ4 in vitro, we obtained a strong enhancement of proliferative rate and a downregulation of cell death-related proteins. In addition, we observed a strong modulation of histone H4 acetylation and Ku70, the limiting factor of DNA double-strand breaks repair machinery implied in apoptosis inhibition and drug resistance acquisition. Moreover, LOX-1Δ4 overexpression is able to increase proliferation in a non-tumorigenic epithelial cell line, MCF12-F, acting as an oncogene. Altogether, these results suggest that LOX-1 may acts as a molecular link among metabolism, inflammation and cancer, indicating its potential role as biomarker and new molecular target, representing an attractive and concrete opportunity to improve current strategies for breast cancer tailored therapy.

The upregulated scavenger receptor CD36 is associated with the progression of nontarget lesions after stent implantation in atherosclerotic rabbits

Background

The incidence of recurrent cardiovascular events from the progression of nontarget lesions (NTLs) is high for percutaneous coronary intervention-treated patients. However, the underlying mechanisms have not been thoroughly elucidated.

Methods

In this study, ten atherosclerotic rabbits with multiple plaques in the upper and lower segments of abdominal aorta (group A) were randomly divided into two subgroups: group A1 underwent intravascular ultrasound examination and stent implantation in the lower segments of the abdominal aorta (n=5), whereas group A2 was without stenting (n=5). Group B was a control group without balloon injury. The serum levels of high-sensitivity CRP, interleukin-6 (IL-6), oxidized low-density lipoprotein, and CD36 were assessed via ELISA at five time points between the 10th and 18th weeks. The upper abdominal aorta was examined via the immunohistochemical stain and Western blotting of matrix metallopeptidase 9 (MMP-9), CD36, IL-6, and tumor necrosis factor α.

Results

As a result, we found that stent implantation aggravated serum levels of CD36, oxidative stress, and inflammatory cytokines. Meanwhile, the upper abdominal arterial plaque burden significantly increased after stenting by intravascular ultrasound. Immunohistochemistry and Western blotting showed that the local NTLs’ matrix metallopeptidase 9, CD36, IL-6, and tumor necrosis factor α expressions in group A1 were significantly higher than those in groups A2 and B (P<0.05–0.01). More importantly, a strong correlation was identified between CD36 expression and NTLs’ plaque burden before the rabbits were killed.

Conclusion

Taken together, stent implantation accelerated inflammation, induced oxidative stress, and increased the NTLs’ progression, which were associated with the upregulated CD36 expression.

Elevation of Oxidized Lipoprotein of Low Density in Users of Combined Oral Contraceptives

Background

The use of combined oral contraceptive (COC) has been related to changes in glycemic, lipid metabolism, increased oxidative stress, and systemic blood pressure, which could suggest a higher oxidation of low-density lipoprotein cholesterol (LDL-cholesterol) in women on use of COC.

Objective

To test the hypothesis that there is a difference in the plasma values of oxidized LDL among women who use and do not use COC, as well as to evaluate the correlation between it and the lipid profile and high-sensitivity C-reactive protein (hs-CRP).

Methods

Forty-two women with ages between 18 and 35 years old, who were eutrophic, irregularly active, with triglycerides < 150 mg/dL, blood glucose < 100 mg/dL, and who used or did not use COC were selected. These women were allocated in the COC group, formed by 21 women on COC use for at least 1 year; and a control group (CG), consisting of 21 women who had not used any type of hormonal contraceptive for at least 1 year. A significance level of 5% was adopted for statistical analyses.

Results

It was observed that GCOC showed higher values of oxidized LDL than the CG, respectively 384 mU/mL versus 283 mU/mL (p < 0.01). A positive correlation between oxidized LDL and LDL-cholesterol (r = 0.3, p < 0.05), with total cholesterol (r = 0.47, p < 0.01) and with triglycerides (r = 0.32, p < 0.03) was observed, and there was no correlation with the hs-CRP. In the categorized analysis of oxidized LDL, 71.4% of GCOC women, and 28.6% of the CG remained above the established cutoff point.

Conclusion

Women who use COC have higher plasma levels of oxidized LDL, and there is a positive correlation between oxidized LDL and other lipid variables.

Factors related to metabolic parameters in medicated patients with major depressive disorder--a naturalistic study

The aim of this study was to examine the metabolic parameters, including body mass index (BMI), homeostasis model assessment-estimated insulin resistance (HOMA-IR), homeostasis model assessment-estimated pancreatic β-cell function (HOMA-β), and lipid plasma level, in medicated patients with major depressive disorder (MDD) and to assess factors related to metabolic parameters in patients with MDD. 121 patients with MDD and 63 controls were recruited. The Hamilton Depression Rating Scale (HDRS), Wisconsin Card Sorting Test (WCST), Continuous Performance Test (CPT), and Finger-Tapping Test (FTT), were administered. BMI, HOMA-IR, and HOMA-β were calculated as modifiable metabolic parameters. The FTT results and BMI in depressed patients were significantly poorer and lower, respectively, than those of the controls. However, no significant differences were noted between MDD patients and controls included metabolic parameters and other neuropsychological tests. Among depressed patients, higher BMI is significantly related with lower education, no tobacco use, and male. The result demonstrated metabolic parameters could be neutral among medicated patients with MDD, particularly in non-elderly Asian individuals. The deficits of psychomotor speed could be more prominent than other cognitive alterations in patient with MDD.

Analyzing 2000 in Vivo Drug Delivery Data Points Reveals Cholesterol Structure Impacts Nanoparticle Delivery

Lipid nanoparticles (LNPs) are formulated using unmodified cholesterol. However, cholesterol is naturally esterified and oxidized in vivo, and these cholesterol variants are differentially trafficked in vivo via lipoproteins including LDL and VLDL. We hypothesized that incorporating the same cholesterol variants into LNPs-which can be structurally similar to LDL and VLDL-would alter nanoparticle targeting in vivo. To test this hypothesis, we quantified how >100 LNPs made with six cholesterol variants delivered DNA barcodes to 18 cell types in wild-type, LDLR-/-, and VLDLR-/- mice that were both age-matched and female. By analyzing ∼2000 in vivo drug delivery data points, we found that LNPs formulated with esterified cholesterol delivered nucleic acids more efficiently than LNPs formulated with regular or oxidized cholesterol when compared across all tested cell types in the mouse. We also identified an LNP containing cholesteryl oleate that efficiently delivered siRNA and sgRNA to liver endothelial cells in vivo. Delivery was as-or more-efficient as the same LNP made with unmodified cholesterol. Moreover, delivery to liver endothelial cells was 3 times more efficient than delivery to hepatocytes, distinguishing this oleate LNP from hepatocyte-targeting LNPs. RNA delivery can be improved by rationally selecting cholesterol variants, allowing optimization of nanoparticle targeting.

Long-Term Consumption of Cuban Policosanol Lowers Central and Brachial Blood Pressure and Improves Lipid Profile With Enhancement of Lipoprotein Properties in Healthy Korean Participants

Metabolic syndrome is closely associated with higher risk of hypertension, cardiovascular disease (CVD), diabetes and stroke. The aim of the present study was to investigate the long-term effects of policosanol supplementation on blood pressure (BP) and the lipid profile in healthy Korean participants with pre-hypertension (systolic 120–139 mmHg, diastolic 85–89 mmHg). This randomized, double-blinded, and placebo-controlled trial included 84 healthy participants who were randomly assigned to three groups receiving 10 mg of policosanol, 20 mg of policosanol, or placebo for 24 weeks. The BP, lipid profile, and anthropometric factors were measured pre- and post-intervention and then compared. Based on an average of three measurements of brachial BP, the policosanol 20 mg group showed the most significant reduction in average systolic BP (SBP) from 138 ± 12 mmHg at week 0 to 126 ± 13 mmHg at week 24 (p < 0.0001). The policosanol 20 mg group also showed significant reductions in aortic SBP and DBP up to 9% (p = 0.00057) and 8% (p = 0.004), respectively compared with week 0. Additionally, blood renin and aldosterone levels were significantly reduced in the policosanol 20 mg group up to 63% (p < 0.01) and 42% (p < 0.05), respectively, at week 24. For the blood lipid profile, the policosanol 10 mg and 20 mg groups showed significant reductions in total cholesterol (TC) of around 8% (p = 0.029) and 13% (p = 0.0004), respectively, at week 24 compared with week 0. Serum HDL-C level significantly increased up to 16% and 12% in the policosanol 10 mg (p = 0.002) and 20 mg (p = 0.035) group, respectively. The study results suggest that long-term policosanol consumption simultaneously reduces peripheral BP as well as aortic BP accompanied by elevation of HDL-C and % HDL-C in TC in a dose-dependent manner.

Relation between circulating oxidized-LDL and metabolic syndrome in children with obesity: the role of hypertriglyceridemic waist phenotype

BACKGROUND

The association between oxidative stress (OS) and metabolic syndrome (MetS) has been reported in adults. We analyzed the relation between circulating oxidized low-density lipoproteins (Ox-LDL) and MetS in pediatric ages in order to define whether plasma Ox-LDL levels are correlated to obesity and whether oxidative damage, using serum Ox-LDL levels as a proxy, are associated with MetS.

METHODS

We enrolled 178 children (11.8±2.6 years). On the basis of a body mass index (BMI) threshold, the subjects were classified as: normal weight BMI <75th percentile; overweight BMI 75-97th percentile; obese BMI >97th percentile. Patients were classified as having MetS if they met three or more of the following criteria for age and sex: BMI >97th percentile, triglyceride levels >95th percentile, high-density lipoprotein (HDL) cholesterol level <5th percentile, systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) >95th percentile and impaired glucose tolerance.

RESULTS

Obese children showed increased MetS prevalence (p=0.001) and higher Ox-LDL levels compared to normal- and overweight subjects (p<0.05), with a limited relation between Ox-LDL and MetS (p=0.06). Waist-to-height ratio (W/HtR) (p=0.02), triglycerides (TG) (p=0.001) and LDL-cholesterol (p<0.001) resulted independent predictors of increased plasma Ox-LDL levels.

CONCLUSIONS

Oxidative damage was correlated with a hypertriglyceridemic waist phenotype and can be a precocious marker of MetS and cardiometabolic risk in obese children.

Comparison of the effects of flaxseed oil and sunflower seed oil consumption on serum glucose, lipid profile, blood pressure, and lipid peroxidation in patients with metabolic syndrome

BACKGROUND

Metabolic syndrome (MetSyn) increases the risk of type II diabetes and morbidity and mortality due to cardiovascular diseases. Flaxseed oil (FO), as a functional food, is one of the major vegetal sources of essential omega-3 fatty acids.

OBJECTIVE

This study aimed to compare the effects of consumption of FO and sunflower seed oil (SO) on lipid peroxidation and other symptoms of MetSyn.

METHODS

This randomized controlled interventional trial was conducted on 60 volunteers aged 30 to 60 years who were diagnosed with MetSyn in Shiraz, Iran. The participants who fulfilled the inclusion criteria were randomly assigned to SO (n = 30, receiving 25 mL/d SO) and FO (n = 30, receiving 25 ml/d FO) groups using block randomization. The diets were identical for all the participants. Blood pressure (BP), serum lipid, fasting blood sugar, and malondialdehyde were measured at baseline and at the end of week 7.

RESULT

The results showed no significant difference between the 2 groups regarding blood lipid levels and fasting blood sugar at the end of the study. However, significant reductions in total cholesterol, low-density lipoprotein cholesterol (5.6% in FO and 10.8% in SO), and triglyceride levels were seen within each group after treatment with FO and SO (P < .05). Nonetheless, between-group changes were significant (<0.05) for systolic BP (mean [±standard deviation {SD}] changes were -14.0 ± 22.41 in the FO group [P = .004] and 0.92 ± 8.70 in the SO group [P = .594]) and diastolic BP (mean [±SD] changes were -4.26 ± 7.44 in the FO group [P = .007] and 1.30 ± 6.91 in the SO group [P = .344]), but marginally significant (P = .053) for malondialdehyde level (mean [±SD] changes were -1.29 ± 1.48 in the FO group [P < .001] and -0.52 ± 1.34 in the SO group [P = .52]). A significant decrease in weight was also found in both groups. However, waist circumference decreased significantly only in the FO group at the end of the study (P < .05).

CONCLUSION

Our results indicated that dietary FO could be effective in amelioration of some symptoms of MetSyn and decrease BP and lipid peroxidation.

Potential of Metformin to Improve Cardiac Risk in Postpartum Women with Gestational Diabetes

Objective

Pregnancy is associated with an increase in total cholesterol, high density lipoproteins (HDL), and low-density lipoproteins (LDL). Postpartum, HDL and LDL decrease over the first 12 weeks postpartum. Oxidized LDL (ox-LDL) is a marker of oxidative stress-related inflammation, which is associated with obesity and also with development of cardiovascular disease. Cardiovascular protection and weight loss are benefits from metformin, especially in women with diabetes. The objective of this study was to compare changes in lipid profiles and biomarkers for obesity during the initial 6 weeks postpartum between women with gestational diabetes mellitus (GDM) treated with metformin versus placebo.

Methods

This was a planned ancillary study of a randomized controlled trial compares metformin versus placebo in women with GDM for postpartum weight loss. Two 3 mL blood samples were collected within 24 h of delivery and 6 weeks postpartum immediately processed after collection then stored at −20°C until completion of clinical trial prior to analysis. Change in the median plasma concentrations of total cholesterol, HDL, ox-LDL, glucose, insulin, leptin, and unacylated ghrelin were compared between study groups.

Results

Of the 77 postpartum women were included, 35 received metformin and 42 received placebo. There was less of a reduction in HDL in the metformin group compared to placebo (−2.3 versus −7.5 mg/dL, p = 0.019). In addition, there was a greater reduction in ox-LDL in those receiving metformin (−12.2 versus −3.8 mg/dL, p = 0.038). No other differences were observed in the selected biomarkers evaluated.

Conclusion

Biomarker levels of HDL and ox-LDL were positively affected during the initial 6 weeks postpartum in GDM women treated with metformin. Additional studies with a longer duration of metformin treatment in the postpartum period are warranted to evaluate long-term potential benefits.

Measurement and Clinical Significance of Biomarkers of Oxidative Stress in Humans

Oxidative stress is the result of the imbalance between reactive oxygen species (ROS) formation and enzymatic and nonenzymatic antioxidants. Biomarkers of oxidative stress are relevant in the evaluation of the disease status and of the health-enhancing effects of antioxidants. We aim to discuss the major methodological bias of methods used for the evaluation of oxidative stress in humans. There is a lack of consensus concerning the validation, standardization, and reproducibility of methods for the measurement of the following: (1) ROS in leukocytes and platelets by flow cytometry, (2) markers based on ROS-induced modifications of lipids, DNA, and proteins, (3) enzymatic players of redox status, and (4) total antioxidant capacity of human body fluids. It has been suggested that the bias of each method could be overcome by using indexes of oxidative stress that include more than one marker. However, the choice of the markers considered in the global index should be dictated by the aim of the study and its design, as well as by the clinical relevance in the selected subjects. In conclusion, the clinical significance of biomarkers of oxidative stress in humans must come from a critical analysis of the markers that should give an overall index of redox status in particular conditions.

Endothelial Dysfunction in Obesity

Chronic inflammatory state in obesity causes dysregulation of the endocrine and paracrine actions of adipocyte-derived factors, which disrupt vascular homeostasis and contribute to endothelial vasodilator dysfunction and subsequent hypertension. While normal healthy perivascular adipose tissue (PVAT) ensures the dilation of blood vessels, obesity-associated PVAT leads to a change in profile of the released adipo-cytokines, resulting in a decreased vasorelaxing effect. Adipose tissue inflammation, nitric oxide (NO)-bioavailability, insulin resistance and oxidized low-density lipoprotein (oxLDL) are main participating factors in endothelial dysfunction of obesity. In this chapter, disruption of inter-endothelial junctions between endothelial cells, significant increase in the production of reactive oxygen species (ROS), inflammation mediators, which are originated from inflamed endothelial cells, the balance between NO synthesis and ROS , insulin signaling and NO production, and decrease in L-arginine/endogenous asymmetric dimethyl-L-arginine (ADMA) ratio are discussed in connection with endothelial dysfunction in obesity.

Novel methods in pulmonary hypertension phenotyping in the age of precision medicine (2015 Grover Conference series)

Among pulmonary vascular diseases, pulmonary hypertension (PH) is the best studied and has been the focus of our work. The current classification of PH is based on a relatively simple combination of patient characteristics and hemodynamics. This leads to inherent limitations, including the inability to customize treatment and the lack of clarity from a more granular identification based on individual patient phenotypes. Accurate phenotyping of PH can be used in the clinic to select therapies and determine prognosis and in research to increase the homogeneity of study cohorts. Rapid advances in the mechanistic understanding of the disease, improved imaging methods, and innovative biomarkers now provide an opportunity to define novel PH phenotypes. We have recently shown that altered metabolism may affect nitric oxide levels and protein glycosylation, the peripheral circulation (which may provide insights into the response to therapy), and exhaled-breath analysis (which may be useful in disease evaluation). This review is based on a talk presented during the 2015 Grover Conference and highlights the relevant literature describing novel methods to phenotype pulmonary arterial hypertension patients by using approaches that involve the pulmonary and systemic (peripheral) vasculature. In particular, abnormalities in metabolism, the pulmonary and peripheral circulation, and exhaled breath in PH may help identify phenotypes that can be the basis for a precision-medicine approach to PH management. These approaches may also have a broader scope and may contribute to a better understanding of other diseases, such as asthma, diabetes, and cancer.

Effects of Hormone Therapy on Oxidative Stress in Postmenopausal Women with Metabolic Syndrome

The aim of this study was to determine the effect of oral hormone therapy (HT) on oxidative stress (OS) in postmenopausal women with metabolic syndrome (MetS). A randomized, double blind, placebo-controlled trial was carried out. We formed four groups of 25 women each; healthy (HW) and MetS women (MSW) were assigned to HT (1 mg/day of estradiol valerate plus 5 mg/10 day of medroxiprogesterone) or placebo. We measured plasma lipoperoxides, erythrocyte superoxide dismutase and glutathione peroxidase, total plasma antioxidant status and uric acid, as OS markers. Alternative cut-off values of each parameter were defined and a stress score (SS) ranging from 0 to 7 was used as total OS. MetS was defined according to National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATPIII) criteria. Participants were seen at baseline, 3 and 6 months. After 6 months, MetS decreased in MSW-HT (48%), their triglycerides and high-density lipoprotein cholesterol (HDL-c) improved; in the other groups no difference was found. SS in MSW-HT decreased (3.8 ± 0.3 to 1.7 ± 0.3, p < 0.05) and OS was also reduced (44%), this effect was evident since 3 mo. HW-HT with high OS also decreased (40%). In placebo groups there was no change. Our findings suggest that HT improve lipids and OS associated to MetS in postmenopausal women.

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Epicardial adipose tissue has a unique transcriptome modified in severe coronary artery disease

OBJECTIVE

To explore the transcriptome of epicardial adipose tissue (EAT) as compared to subcutaneous adipose tissue (SAT) and its modifications in a small number of patients with coronary artery disease (CAD) versus valvulopathy.

METHODS

SAT and EAT samples were obtained during elective cardiothoracic surgeries. The transcriptome of EAT was evaluated, as compared to SAT, using an unbiased, whole-genome approach in subjects with CAD (n = 6) and without CAD (n = 5), where the patients without CAD had cardiac valvulopathy.

RESULTS

Relative to SAT, EAT is a highly inflammatory tissue enriched with genes involved in endothelial function, coagulation, immune signaling, potassium transport, and apoptosis. EAT is lacking in expression of genes involved in protein metabolism, tranforming growth factor-beta (TGF-beta) signaling, and oxidative stress. Although underpowered, in subjects with severe CAD, there is an expression trend suggesting widespread downregulation of EAT encompassing a diverse group of gene sets related to intracellular trafficking, proliferation/transcription regulation, protein catabolism, innate immunity/lectin pathway, and ER stress.

CONCLUSIONS

The EAT transcriptome is unique when compared to SAT. In the setting of CAD versus valvulopathy, there is possible alteration of the EAT transcriptome with gene suppression. This pilot study explores the transcriptome of EAT in CAD and valvulopathy, providing new insight into its physiologic and pathophysiologic roles.

Sexual dimorphism of lipid metabolism in very long-chain acyl-CoA dehydrogenase deficient (VLCAD-/-) mice in response to medium-chain triglycerides (MCT)

Medium-chain triglycerides (MCT) are widely applied in the treatment of long-chain fatty acid oxidation disorders. Previously it was shown that long-term MCT supplementation strongly affects lipid metabolism in mice. We here investigate sex-specific effects in mice with very-long-chain-acyl-CoA dehydrogenase (VLCAD) deficiency in response to a long-term MCT modified diet. We quantified blood lipids, acylcarnitines, glucose, insulin and free fatty acids, as well as tissue triglycerides in the liver and skeletal muscle under a control and an MCT diet over 1 year. In addition, visceral and hepatic fat content and muscular intramyocellular lipids (IMCL) were assessed by in vivo(1)H magnetic resonance spectroscopy (MRS) techniques. The long-term application of an MCT diet induced a marked alteration of glucose homeostasis. However, only VLCAD-/- female mice developed a severe metabolic syndrome characterized by marked insulin resistance, dyslipidemia, severe hepatic and visceral steatosis, whereas VLCAD-/- males seemed to be protected and only presented with milder insulin resistance. Moreover, the highly saturated MCT diet is associated with a decreased hepatic stearoyl-CoA desaturase 1 (SCD1) activity in females aggravating the harmful effects of a saturated MCT diet. Long-term MCT supplementation deeply affects lipid metabolism in a sexual dimorphic manner resulting in a severe metabolic syndrome only in female mice. These findings are striking since the first signs of insulin resistance already occur in female VLCAD-/- mice during their reproductive period. How these metabolic adaptations are finally regulated needs to be determined. More important, the relevance of these findings for humans under these dietary modifications needs to be investigated.

Oxidized LDL and NO synthesis--Biomarkers of endothelial dysfunction and ageing

Oxidized LDL (oxLDL) and nitric oxide (NO) exert contradictory actions within the vascular endothelium microenvironment influencing key events in atherogenesis. OxLDL and NO are so far regarded as representative parameters of oxidative stress and endothelial dysfunction, new targets in prevention, diagnosis and therapy of cardiovascular diseases, and also as candidate biomarkers in evaluating the human biological age. The aim of this review is to explore recent literature on molecular mechanisms and pathophysiological relationships between LDL oxidation, NO synthesis and vascular endothelium function/dysfunction in ageing, focusing on the following aspects: (1) the impact of metabolic status on both LDL oxidation and NO synthesis in relation with oxidative stress, (2) the use of oxidized LDL and NO activity as biomarkers in human studies reporting on cardiovascular outcomes, and (3) evidences supporting the importance of oxidized LDL and NO activity as relevant biomarkers in vascular ageing and age-related diseases.

Serum fetuin-A and arginase-1 in human obesity model: Is there any interaction between inflammatory status and arginine metabolism?

Obesity is a major risk factor for many chronic metabolic diseases such as inflammation, insulin resistance (IR) and fatty liver injury. It was reported that obesity causes some variations on the serum levels of fetuin-A and is associated with arginine metabolism, especially arginase-1 levels. The aim of our study was to evaluate, the interaction and possible changes of these liver over produced proteins, fetuin-A and arginase-1 levels in obesity-related inflammatory status. Study groups were composed of individuals aged between 19 and 63 (n = 62). The control group included healthy subjects with BMI < 25, obese group included obese patients with BMI > 30 and with no other chronic disease. Biochemical markers were determined by an auto-analyzer. Adiponectin, fetuin-A, arginase-1, asymmetric dimethylarginine (ADMA), arginine, Hexanoyl-lysine (HEL) and leptin levels were measured with commercial ELISA immunoassay kits. Nitrite and nitrate were determined with colorimetric assay kit in serum samples. High sensitive C-reactive protein (hsCRP) levels and liver function enzymes activities were higher in the obese group in respect to the control group. Serum fetuin-A, arginase-1 and leptin levels were increased but adiponectin levels were decreased in obese subjects. Fetuin-A levels showed significant correlations with arginase-1 and HOMA-IR. Consequently, we carried out an investigation about higher serum fetuin-A and arginase-1 levels may have an important role in obesity and obesity-related liver damage.

Co-existence of insulin resistance and high concentrations of circulating oxidized LDL lipids

INTRODUCTION

Insulin metabolism has been previously linked to oxidized low-density lipoproteins (ox-LDL), but corroborating intervention studies are lacking. We investigated whether changes in ox-LDL levels are accompanied by changes in insulin sensitivity in a 32-month life-style intervention study.

MATERIALS AND METHODS

A 2-month weight reduction was followed by 6-month diet and exercise counselling and a 2-year follow-up period. Men of 35-50 years of age, BMI ≥ 30 kg/m(2), and waist circumference > 100 cm were recruited via newspapers in the city of Tampere, Finland. Of the 90 men meeting the inclusion criteria, 67 (76%) completed the study. Ox-LDL was estimated as the presence of oxidized lipids in LDL. Homeostasis model assessment of insulin resistance (HOMA-IR), ox-LDL, and ratio of ox-LDL and high-density lipoprotein cholesterol (ox-LDL/HDL-c) were used as the main outcome measures.

RESULTS

The detected changes in HOMA-IR were strikingly similar to those in ox-LDL and ox-LDL/HDL-c. Compared to the first HOMA-IR quartile, the fourth quartile had 23%-51% higher concentrations in ox-LDL and ox-LDL/HDL-c at all time points (P < 0.05 for all).

CONCLUSION

This weight reduction intervention study adds evidence to support the connection between insulin metabolism and oxidized LDL, possibly contributing to the higher incidence of atherosclerotic cardiovascular diseases among diabetic patients.