Total Outflow of High-Density Lipoprotein-Cholesteryl Esters from Plasma Is Decreased in a Model of 3/4 Renal Mass Reduction.

(1) Background: Previous studies have enriched high-density lipoproteins (HDL) using cholesteryl esters in rabbits with a three-quarter reduction in functional renal mass, suggesting that the kidneys participate in the cholesterol homeostasis of these lipoproteins. However, the possible role of the kidneys in lipoprotein metabolism is still controversial. To understand the role of the kidneys in regulating the HDL lipid content, we determined the turnover of HDL-cholesteryl esters in rabbits with a three-quarter renal mass reduction. (2) Methods: HDL subclass characterization was conducted, and the kinetics of plasma HDL-cholesteryl esters, labeled with tritium, were studied in rabbits with a 75% reduction in functional renal mass (Ntx). (3) Results: The reduced renal mass triggered the enrichment of cholesterol, specifically cholesteryl esters, in HDL subclasses. The exchange of cholesteryl esters between HDL and apo B-containing lipoproteins (VLDL/LDL) was not significantly modified in Ntx rabbits. Moreover, the cholesteryl esters of HDL and VLDL/LDL fluxes from the plasmatic compartment tended to decrease, but they only reached statistical significance when both fluxes were added to the Nxt group. Accordingly, the fractional catabolic rate (FCR) of the HDL-cholesteryl esters was lower in Ntx rabbits, concomitantly with its accumulation in HDL subclasses, probably because of the reduced mass of renal cells requiring this lipid from lipoproteins.

Eicosapentaenoic and Docosahexaenoic Acid Supplementation Increases HDL Content in n-3 Fatty Acids and Improves Endothelial Function in Hypertriglyceridemic Patients.

High-density lipoproteins (HDLs) are known to enhance vascular function through different mechanisms, including the delivery of functional lipids to endothelial cells. Therefore, we hypothesized that omega-3 (n-3) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content of HDLs would improve the beneficial vascular effects of these lipoproteins. To explore this hypothesis, we performed a placebo-controlled crossover clinical trial in 18 hypertriglyceridemic patients without clinical symptoms of coronary heart disease who received highly purified EPA 460 mg and DHA 380 mg, twice a day for 5 weeks or placebo. After 5 weeks of treatment, patients followed a 4-week washout period before crossover. HDLs were isolated using sequential ultracentrifugation for characterization and determination of fatty acid content. Our results showed that n-3 supplementation induced a significant decrease in body mass index, waist circumference as well as triglycerides and HDL-triglyceride plasma concentrations, whilst HDL-cholesterol and HDL-phospholipids significantly increased. On the other hand, HDL, EPA, and DHA content increased by 131% and 62%, respectively, whereas 3 omega-6 fatty acids significantly decreased in HDL structures. In addition, the EPA-to-arachidonic acid (AA) ratio increased more than twice within HDLs suggesting an improvement in their anti-inflammatory properties. All HDL-fatty acid modifications did not affect the size distribution or the stability of these lipoproteins and were concomitant with a significant increase in endothelial function assessed using a flow-mediated dilatation test (FMD) after n-3 supplementation. However, endothelial function was not improved in vitro using a model of rat aortic rings co-incubated with HDLs before or after treatment with n-3. These results suggest a beneficial effect of n-3 on endothelial function through a mechanism independent of HDL composition. In conclusion, we demonstrated that EPA and DHA supplementation for 5 weeks improved vascular function in hypertriglyceridemic patients, and induced enrichment of HDLs with EPA and DHA to the detriment of some n-6 fatty acids. The significant increase in the EPA-to-AA ratio in HDLs is indicative of a more anti-inflammatory profile of these lipoproteins.

Trp Fluorescence Redshift during HDL Apolipoprotein Denaturation Is Increased in Patients with Coronary Syndrome in Acute Phase: A New Assay to Evaluate HDL Stability.

High-density lipoproteins' (HDL) stability is a determinant of their residence times in plasma and consequently an important parameter that influences the beneficial properties of these lipoproteins. Since there are no accessible procedures for this purpose, here, we describe the methodological conditions to assess the stability of the HDL based on the redshift of the fluorescence spectrum of tryptophans contained in the structure of HDL-apolipoproteins during incubation with urea 8M. Along the HDL denaturation kinetics, the main variations of fluorescence were observed at the wavelengths of 330, 344, and 365 nm at room temperature. Therefore, HDL denaturation was estimated using the tryptophan (Trp)-ratio of fluorescence intensity (rfi) at such wavelengths. By setting 100% of the measurable denaturation at 26 h, HDL reached 50% after 8 h of incubation with urea. Then, for further analyses we determined the percentage of HDL denaturation at 8 h as an estimation of the stability of these lipoproteins. To explore the potential usefulness of this test, we analyzed the stability of HDL isolated from the plasma of 24 patients diagnosed with acute coronary syndrome (ACS). These HDL presented significantly higher percentages of denaturation (64.9% (58.7-78.4)) than HDLs of healthy individuals (23.3% (20.3-27.0)). These results indicate that HDL in ACS are less stable than in control subjects. Moreover, the percentage of denaturation of HDL correlated with body mass index and aspartate transaminase plasma activity. Furthermore, apo-I, HDL-cholesterol, HDL-triglycerides, and apo A-I-to-triglycerides ratio correlated with the percentage of HDL denaturation, suggesting that the lipoprotein composition is a main determinant of HDL stability. Finally, the percentage of HDL denaturation is the parameter that predicted the presence of ACS as determined by a machine learning procedure and logistic regression analysis. In conclusion, we established the methodological conditions to assess the stability of HDL by a fluorescence-based method that merits exploration in prospective studies for evaluating the coronary artery disease risk.

Resveratrol and Quercetin as Regulators of Inflammatory and Purinergic Receptors to Attenuate Liver Damage Associated to Metabolic Syndrome.

Nonalcoholic fatty liver disease (NAFLD) is considered a manifestation of metabolic syndrome (MS) and is characterized by the accumulation of triglycerides and a varying degree of hepatic injury, inflammation, and repair. Moreover, peroxisome-proliferator-activated receptors (PPARs) play a critical role in the pathophysiological processes in the liver. There is extensive evidence of the beneficial effect of polyphenols such as resveratrol (RSV) and quercetin (QRC) on the treatment of liver pathology; however, the mechanisms underlying their beneficial effects have not been fully elucidated. In this work, we show that the mechanisms underlying the beneficial effects of RSV and QRC against inflammation in liver damage in our MS model are due to the activation of novel pathways which have not been previously described such as the downregulation of the expression of toll-like receptor 4 (TLR4), neutrophil elastase (NE) and purinergic receptor P2Y2. This downregulation leads to a decrease in apoptosis and hepatic fibrosis with no changes in hepatocyte proliferation. In addition, PPAR alpha and gamma expression were altered in MS but their expression was not affected by the treatment with the natural compounds. The improvement of liver damage by the administration of polyphenols was reflected in the normalization of serum transaminase activities.

Effect of a Resveratrol/Quercetin Mixture on the Reversion of Hypertension Induced by a Short-Term Exposure to High Sucrose Levels Near Weaning and a Long-Term Exposure That Leads to Metabolic Syndrome in Rats.

Hypertension is an important global public health problem. Excess sucrose during a short period near weaning (short sucrose period, SSP; sucrose during rat postnatal days 12 to 28) increases the risk of developing hypertension during adulthood and sucrose ingestion for 6 months after weaning also results in metabolic syndrome (MS) accompanied by hypertension. The aim of this study was to test if the mechanisms that lead to hypertension induced by SSP and MS are similarly modified by a resveratrol/quercetin mixture (RSV/QSC) that targets epigenetic cues. We studied the reversion of hypertension by an RSV/QSC mixture administered for 1 month (from month 6 to month 7 of age) in these two models, since it is effective against some signs of MS. RSV/QSC might determine Sirtuin 1 (SIRT1) and Sirtuin 3 (SIRT3) expression that modulates the expression of endothelial nitric oxide synthase (eNOS), which synthesizes nitric oxide (NO), and of superoxide dismutases (SOD1 and 2), which are antioxidant enzymes that have an impact on the NO levels. Short- (SSP) and long-term (MS) exposure to sucrose induced hypertension and RSV/QSC reversed it. It increased the insulin sensitivity, which may determine the eNOS expression. eNOS expression was decreased in aortas from SSP and MS rats and RSV/QSC only elevated its levels in aortas from MS rats. SIRT1 was also only increased in the MS aortas. Hypertension was accompanied by a decrease in total non-enzymatic antioxidant defenses in SSP and MS aortas, which improved with the RSV/QSC treatment. SOD1 expression was not modified by the sucrose treatments, but SOD2 expression was decreased in SSP and MS aortas. The RSV/QSC treatment increased SOD1 expression in MS aortas. SIRT3 was not modified by the sucrose or RSV/QSC treatments. In conclusion, SSP and MS lead to hypertension, but MS leads to more possible epigenetically- regulated mechanisms related to high blood pressure that could be targeted by the RSV/QSC mixture. Therefore, treatment has better effects on hypertension produced by MS.

Microencapsulated Pomegranate Modifies the Composition and Function of High-Density Lipoproteins (HDL) in New Zealand Rabbits.

Previous studies demonstrated that pomegranate, which is a source of several bioactive molecules, induces modifications of high-density lipoproteins (HDL) lipid composition and functionality. However, it remains unclear whether the beneficial effects of pomegranate are related to improvement in the lipid components of HDL. Therefore, in this placebo-controlled study, we characterized the size and lipid composition of HDL subclasses and assessed the functionality of these lipoproteins after 30 days of supplementation with a pomegranate microencapsulated (MiPo) in New Zealand white rabbits. We observed a significant decrease in plasma cholesterol, triglycerides, and non-HDL sphingomyelin, as well as increases in HDL cholesterol and HDL phospholipids after supplementation with MiPo. Concomitantly, the triglycerides of the five HDL subclasses isolated by electrophoresis significantly decreased, whereas phospholipids, cholesterol, and sphingomyelin of HDL subclasses, as well as the HDL size distribution remained unchanged. Of particular interest, the triglycerides content of HDL, estimated by the triglycerides-to-phospholipids ratio, decreased significantly after MiPo supplementation. The modification on the lipid content after the supplementation was associated with an increased resistance of HDL to oxidation as determined by the conjugated dienes formation catalyzed by Cu2+. Accordingly, paraoxonase-1 (PON1) activity determined with phenylacetate as substrate increased after MiPo. The effect of HDL on endothelial function was analyzed by the response to increasing doses of acetylcholine of aorta rings co-incubated with the lipoproteins in an isolated organ bath. The HDL from rabbits that received placebo partially inhibited the endothelium-dependent vasodilation. In contrast, the negative effect of HDL on endothelial function was reverted by MiPo supplementation. These results show that the beneficial effects of pomegranate are mediated at least in part by improving the functionality of HDL, probably via the reduction of the content of triglycerides in these lipoproteins.

Atorvastatin and Fenofibrate Increase the Content of Unsaturated Acyl Chains in HDL and Modify In Vivo Kinetics of HDL-Cholesteryl Esters in New Zealand White Rabbits.

Previous studies demonstrated modifications of high-density lipoproteins (HDL) structure and apolipoprotein (apo) A-I catabolism induced by the atorvastatin and fenofibrate combination. However, it remains unknown whether such structural and metabolic changes of HDL were related to an improvement of the HDL-cholesteryl esters (HDL-CE) metabolism. Therefore, we determined the structure of HDL and performed kinetic studies of HDL-CE radiolabeled with tritium in rabbits treated with atorvastatin, fenofibrate, and a combination of both drugs. The atorvastatin and fenofibrate combination increased the HDL size and the cholesterol and phospholipid plasma concentrations of the largest HDL subclasses. Moreover, the relative amount of unsaturated fatty acids contained in HDL increased, in detriment of saturated fatty acids as determined by gas chromatography-mass spectrometry. The transfers of cholesteryl esters (CE) from HDL to very low-density lipoproteins/low-density lipoproteins (VLDL/LDL) and vice versa were enhanced with atorvastatin, alone or in combination. Moreover, the direct elimination of CE from plasma via VLDL/LDL decreased with fenofibrate, whereas the direct elimination of CE via HDL augmented with the combination treatment. Taken together, the rise of unsaturated fatty acid content and the size increase of HDL, suggest that atorvastatin and fenofibrate induce more fluid HDL particles, which in turn favor an enhanced CE exchange between HDL and VLDL/LDL. Our results contribute to a better understanding of the relationship between the structure and function of HDL during the use of anti-dyslipidemic drugs.

Characterization of immortalized human dermal microvascular endothelial cells (HMEC-1) for the study of HDL functionality.

BACKGROUND: Primary cultures endothelial cells have been used as models of endothelial related diseases such atherosclerosis. Biological behavior of primary cultures is donor-dependent and data could not be easily reproducible; endothelial cell lines are emerging options, particularly, human dermal microvascular endothelial cells (HMEC-1), that should be validated to substitute primary cultures for the study of HDL functions. METHODS: Morphology, size and granularity of cells were assessed by phase contrast microscopy and flow cytometry of HMEC-1. The adhesion molecules, ICAM-1and VCAM-1 after TNF-α stimulation, and endothelial markers CD105 endoglin, as well as HDL receptor SR-BI were determined by flow cytometry. Internalization of HDL protein was demonstrated by confocal microscopy using HDL labeled with Alexa Fluor 488. HUVECs were used as reference to compared the characteristics with HMEC-1. RESULTS: HMEC-1 and HUVEC had similar morphologies, size and granularity. HMEC-1 expressed endothelial markers as HUVECs, as well as functional SR-B1 receptor since the cell line was able to internalize HDL particles. HMEC-1 effectively increased ICAM-1 and VCAM-1 expression after TNF-α stimulation. HUVECs showed more sensibility to TNF-α stimulus but the range of ICAM-1 and VCAM-1 expression was less homogeneous than in HMEC-1, probably due to biological variation of the former. Finally, the expression of adhesion molecules in HMEC-1 was attenuated by co-incubation with HDL. CONCLUSION: HMEC-1 possess characteristics of endothelial cells, similar to HUVECs, being a cell line suitable to evaluate the functionality of HDL vis-à-vis the endothelium.

HDL-Mediated Lipid Influx to Endothelial Cells Contributes to Regulating Intercellular Adhesion Molecule (ICAM)-1 Expression and eNOS Phosphorylation.

Reverse cholesterol transport (RCT) is considered as the most important antiatherogenic role of high-density lipoproteins (HDL), but interventions based on RCT have failed to reduce the risk of coronary heart disease. In contrast to RCT, important evidence suggests that HDL deliver lipids to peripheral cells. Therefore, in this paper, we investigated whether HDL could improve endothelial function by delivering lipids to the cells. Internalization kinetics using cholesterol and apolipoprotein (apo) AI fluorescent double-labeled reconstituted HDL (rHDL), and human dermal microvascular endothelial cells-1 (HMEC-1) showed a fast cholesterol influx (10 min) and a slower HDL protein internalization as determined by confocal microscopy and flow cytometry. Sphingomyelin kinetics overlapped that of apo AI, indicating that only cholesterol became dissociated from rHDL during internalization. rHDL apo AI internalization was scavenger receptor class B type I (SR-BI)-dependent, whereas HDL cholesterol influx was independent of SR-BI and was not completely inhibited by the presence of low-density lipoproteins (LDL). HDL sphingomyelin was fundamental for intercellular adhesion molecule-1 (ICAM-1) downregulation in HMEC-1. However, vascular cell adhesion protein-1 (VCAM-1) was not inhibited by rHDL, suggesting that components such as apolipoproteins other than apo AI participate in HDL's regulation of this adhesion molecule. rHDL also induced endothelial nitric oxide synthase eNOS S1177 phosphorylation in HMEC-1 but only when the particle contained sphingomyelin. In conclusion, the internalization of HDL implies the dissociation of lipoprotein components and a SR-BI-independent fast delivery of cholesterol to endothelial cells. HDL internalization had functional implications that were mainly dependent on sphingomyelin. These results suggest a new role of HDL as lipid vectors to the cells, which could be congruent with the antiatherogenic properties of these lipoproteins.

Current Therapies Focused on High-Density Lipoproteins Associated with Cardiovascular Disease.

High-density lipoproteins (HDL) comprise a heterogeneous family of lipoprotein particles divided into subclasses that are determined by density, size and surface charge as well as protein composition. Epidemiological studies have suggested an inverse correlation between High-density lipoprotein-cholesterol (HDL-C) levels and the risk of cardiovascular diseases and atherosclerosis. HDLs promote reverse cholesterol transport (RCT) and have several atheroprotective functions such as anti-inflammation, anti-thrombosis, and anti-oxidation. HDLs are considered to be atheroprotective because they are associated in serum with paraoxonases (PONs) which protect HDL from oxidation. Polyphenol consumption reduces the risk of chronic diseases in humans. Polyphenols increase the binding of HDL to PON1, increasing the catalytic activity of PON1. This review summarizes the evidence currently available regarding pharmacological and alternative treatments aimed at improving the functionality of HDL-C. Information on the effectiveness of the treatments has contributed to the understanding of the molecular mechanisms that regulate plasma levels of HDL-C, thereby promoting the development of more effective treatment of cardiovascular diseases. For that purpose, Scopus and Medline databases were searched to identify the publications investigating the impact of current therapies focused on high-density lipoproteins.

Differential expression of osteopontin, and osteoprotegerin mRNA in epicardial adipose tissue between patients with severe coronary artery disease and aortic valvular stenosis: association with HDL subclasses.

BACKGROUND: Previous studies suggest a relationship of the epicardial adipose tissue (EAT) with progression and calcification of the atherosclerotic plaque; however, it is unknown if this tissue expresses genes that may participate on these processes and if the expression of these genes is regulated by high-density lipoprotein (HDL) subclasses. METHODS: To explore this possibility, we determined the mRNA expression by qPCR of a pro-calcifying gene (osteopontin (OPN)), and two anti-calcifying genes (osteoprotegerin (OPG) and osteonectin (ON)), in biopsies of EAT obtained from 15 patients with coronary artery disease (CAD) determined by angiography, and 15 patients with diagnostic of aortic valve stenosis but without CAD as control group. We determined the distribution and composition of HDL subclasses by electrophoresis and their statistical relationship with the gene expression in EAT. RESULTS: EAT from CAD patients showed a higher expression level of OPN and OPG than control group, whereas ON expression was similar between groups. Large HDL subclasses were cholesterol-poor in CAD patients as estimated by the cholesterol-to-phospholipid ratio. A linear regression model showed an independent association of OPN expression with HDL3a-cholesterol, and OPG expression with the relative proportion of HDL3b protein. Logistic analysis determined that OPN expression was positively associated with the presence of atherosclerotic plaque CONCLUSION: OPN, ON, and OPG genes are transcribed in EAT; to the exception of ON, the level of expression was different in CAD patients and control group, and correlated with some HDL subclasses, suggesting a new role of these lipoproteins.

Fenofibrate Therapy Restores Antioxidant Protection and Improves Myocardial Insulin Resistance in a Rat Model of Metabolic Syndrome and Myocardial Ischemia: The Role of Angiotensin II.

Renin-angiotensin system (RAS) activation promotes oxidative stress which increases the risk of cardiac dysfunction in metabolic syndrome (MetS) and favors local insulin resistance. Fibrates regulate RAS improving MetS, type-2 diabetes and cardiovascular diseases. We studied the effect of fenofibrate treatment on the myocardic signaling pathway of Angiotensin II (Ang II)/Angiotensin II type 1 receptor (AT1) and its relationship with oxidative stress and myocardial insulin resistance in MetS rats under heart ischemia. Control and MetS rats were assigned to the following groups: (a) sham; (b) vehicle-treated myocardial infarction (MI) (MI-V); and (c) fenofibrate-treated myocardial infarction (MI-F). Treatment with fenofibrate significantly reduced triglycerides, non-high density lipoprotein cholesterol (non-HDL-C), insulin levels and insulin resistance index (HOMA-IR) in MetS animals. MetS and MI increased Ang II concentration and AT1 expression, favored myocardial oxidative stress (high levels of malondialdehyde, overexpression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4), decreased total antioxidant capacity and diminished expression of superoxide dismutase (SOD)1, SOD2 and catalase) and inhibited expression of the insulin signaling cascade: phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PkB, also known as Akt)/Glut-4/endothelial nitric oxide synthase (eNOS). In conclusion, fenofibrate treatment favors an antioxidant environment as a consequence of a reduction of the Ang II/AT1/NOX4 signaling pathway, reestablishing the cardiac insulin signaling pathway. This might optimize cardiac metabolism and improve the vasodilator function during myocardial ischemia.

Inflammation and Oxidative Stress Induced by Obesity, Gestational Diabetes, and Preeclampsia in Pregnancy: Role of High-Density Lipoproteins as Vectors for Bioactive Compounds.

Inflammation and oxidative stress are essential components in a myriad of pathogenic entities that lead to metabolic and chronic diseases. Moreover, inflammation in its different phases is necessary for the initiation and maintenance of a healthy pregnancy. Therefore, an equilibrium between a necessary/pathologic level of inflammation and oxidative stress during pregnancy is needed to avoid disease development. High-density lipoproteins (HDL) are important for a healthy pregnancy and a good neonatal outcome. Their role in fetal development during challenging situations is vital for maintaining the equilibrium. However, in certain conditions, such as obesity, diabetes, and other cardiovascular diseases, it has been observed that HDL loses its protective properties, becoming dysfunctional. Bioactive compounds have been widely studied as mediators of inflammation and oxidative stress in different diseases, but their mechanisms of action are still unknown. Nonetheless, these agents, which are obtained from functional foods, increase the concentration of HDL, TRC, and antioxidant activity. Therefore, this review first summarizes several mechanisms of HDL participation in the equilibrium between inflammation and oxidative stress. Second, it gives an insight into how HDL may act as a vector for bioactive compounds. Third, it describes the relationships between the inflammation process in pregnancy and HDL activity. Consequently, different databases were used, including MEDLINE, PubMed, and Scopus, where scientific articles published in the English language up to 2023 were identified.

High Sucrose Ingestion during a Critical Period of Vessel Development Promotes the Synthetic Phenotype of Vascular Smooth Muscle Cells and Modifies Vascular Contractility Leading to Hypertension in Adult Rats.

Cardiometabolic diseases, including hypertension, may result from exposure to high sugar diets during critical periods of development. Here, we studied the effect of sucrose ingestion during a critical period (CP) between postnatal days 12 and 28 of the rat on blood pressure, aortic histology, vascular smooth muscle phenotype, expression of metalloproteinases 2 and 9, and vascular contractility in adult rats and compared it with those of adult rats that received sucrose for 6 months and developed metabolic syndrome (MS). Blood pressure increased to a similar level in CP and MS rats. The diameter of lumen, media, and adventitia of aortas from CP rats was decreased. Muscle fibers were discontinuous. There was a decrease in the expression of alpha-actin in CP and MS rat aortas, suggesting a change to the secretory phenotype in vascular smooth muscle. Metalloproteinases 2 and 9 were decreased in CP and MS rats, suggesting that phenotype remains in an altered steady stationary state with little interchange of the vessel matrix. Aortic contraction to norepinephrine did not change, but aortic relaxation was diminished in CP and MS aortas. In conclusion, high sugar diets during the CP increase predisposition to hypertension in adults.

Nutraceuticals for Complementary Treatment of Multisystem Inflammatory Syndrome in Children: A Perspective from Their Use in COVID-19.

Multisystem inflammatory syndrome in children (MIS-C) has been widely reported in some children diagnosed with SARS-CoV-2. Clinical signs of MIS-C are manifested at 2 to 4 weeks after SARS-CoV-2 infection, where elevated biomarkers of inflammation and cardiac dysfunction are the hallmark of this syndrome when infection or exposure to SARS-CoV-2 has been confirmed. However, after two years of acknowledgment, MIS-C treatment is still under research to reach safety and effectiveness in the acute phase in children. Therefore, in this review, we discuss the potential use of natural compounds with antioxidant and anti-inflammatory effects to reduce collateral damage caused by hyperinflammation in MIS-C pathology for new research in treatment and interventions.

Native Low-Density Lipoproteins Act in Synergy with Lipopolysaccharide to Alter the Balance of Human Monocyte Subsets and Their Ability to Produce IL-1 Beta, CCR2, and CX3CR1 In Vitro and In Vivo: Implications in Atherogenesis.

Increasing evidence has demonstrated that oxidized low-density lipoproteins (oxLDL) and lipopolysaccharide (LPS) enhance accumulation of interleukin (IL)-1 beta-producing macrophages in atherosclerotic lesions. However, the potential synergistic effect of native LDL (nLDL) and LPS on the inflammatory ability and migration pattern of monocyte subpopulations remains elusive and is examined here. In vitro, whole blood cells from healthy donors (n = 20) were incubated with 100 µg/mL nLDL, 10 ng/mL LPS, or nLDL + LPS for 9 h. Flow cytometry assays revealed that nLDL significantly decreases the classical monocyte (CM) percentage and increases the non-classical monocyte (NCM) subset. While nLDL + LPS significantly increased the number of NCMs expressing IL-1 beta and the C-C chemokine receptor type 2 (CCR2), the amount of NCMs expressing the CX3C chemokine receptor 1 (CX3CR1) decreased. In vivo, patients (n = 85) with serum LDL-cholesterol (LDL-C) >100 mg/dL showed an increase in NCM, IL-1 beta, LPS-binding protein (LBP), and Castelli's atherogenic risk index as compared to controls (n = 65) with optimal LDL-C concentrations (≤100 mg/dL). This work demonstrates for the first time that nLDL acts in synergy with LPS to alter the balance of human monocyte subsets and their ability to produce inflammatory cytokines and chemokine receptors with prominent roles in atherogenesis.

Enzymatic assessment of cholesterol on electrophoresis gels for estimating HDL size distribution and plasma concentrations of HDL subclasses.

The aim of this study was to develop an enzymatic cholesterol staining method to determine HDL subclasses in a polyacrylamide gradient gel electrophoresis, which further allows staining by protein in the same electrophoresis lane. HDLs from 120 healthy individuals were separated through nondenaturing PAGE. HDLs were stained for cholesterol using an enzymatic semisolid mixture. Once the gels were unstained, they were stained again for proteins with Coomassie blue. The proportions of HDL subclasses were determined by densitometry. HDL subclasses were transformed to concentrations using as reference HDL-cholesterol plasma levels. This method is comparable in linearity and reproducibility to Coomassie blue staining, although it provides quantitative data. As expected, HDL size distribution shifted toward larger particles when determined by cholesterol as compared with protein. With this method, we observed different proportions of HDL subclasses between men and women as compared with Coomassie blue staining. We described a method to determine HDL size distribution by enzymatic cholesterol staining on polyacrylamide gels. The method allows the quantification of the cholesterol plasma concentration of each HDL subclass with the possibility to further stain the protein in the same sample. The combination of HDL staining by cholesterol and protein on electrophoresis gels provides information that may have clinical relevance.

The c.*52 A/G and c.*773 A/G Genetic Variants in the UTR'3 of the LDLR Gene Are Associated with the Risk of Acute Coronary Syndrome and Lower Plasma HDL-Cholesterol Concentration.

Dyslipidemia has a substantial role in the development of acute coronary syndrome (ACS). Low-density lipoprotein receptor (LDLR) plays a critical role in plasma lipoprotein hemostasis, which is involved in the formation of atherosclerotic plaque. This study aimed to evaluate whether LDLR gene polymorphisms are significantly associated with ACS and the plasma lipids profile. Three LDLR gene polymorphisms located in the UTR'3 region (c.*52 A/G, c.*504 A/G, and c.* 773 A/G) were determined using TaqMan genotyping assays in a group of 618 ACS patients and 666 healthy controls. Plasma lipids profile concentrations were determined by enzymatic/colorimetric assays. Under co-dominant and recessive models, the c.*52 A allele of the c.*52 A/G polymorphism was associated with a higher risk of ACS (OR = 2.02, pCCo-dom = 0.033, and OR = 2.00, pCRes = 0.009, respectively). In the same way, under co-dominant and recessive models, the c.*773 G allele of the c.*773 A/G polymorphism was associated with a high risk of ACS (OR = 2.04, pCCo-dom = 0.027, and OR = 2.01, pCRes = 0.007, respectively). The "AAG" haplotype was associated with a high risk of ACS (OR = 1.22, pC = 0.016). The c.*52 AA genotype showed a lower HDL-C concentration than individuals with the GG genotype. In addition, carriers of c.*773 GG genotype carriers had a lower concentration of the high-density lipoprotein-cholesterol (HDL-C) than subjects with the AA genotype. Our data suggest the association of the LDLRc.*773 A/G and LDLR c.*52 A/G polymorphisms with both the risk of developing ACS and with a lower concentration of HDL-C in the study population.

Nonclassical Axis of the Renin-Angiotensin System and Neprilysin: Key Mediators That Underlie the Cardioprotective Effect of PPAR-Alpha Activation during Myocardial Ischemia in a Metabolic Syndrome Model.

The activation of the renin-angiotensin system (RAS) participates in the development of metabolic syndrome (MetS) and in heart failure. PPAR-alpha activation by fenofibrate reverts some of the effects caused by these pathologies. Recently, nonclassical RAS components have been implicated in the pathogenesis of hypertension and myocardial dysfunction; however, their cardiac functions are still controversial. We evaluated if the nonclassical RAS signaling pathways, directed by angiotensin III and angiotensin-(1-7), are involved in the cardioprotective effect of fenofibrate during ischemia in MetS rats. Control (CT) and MetS rats were divided into the following groups: (a) sham, (b) vehicle-treated myocardial infarction (MI-V), and (c) fenofibrate-treated myocardial infarction (MI-F). Angiotensin III and angiotensin IV levels and insulin increased the aminopeptidase (IRAP) expression and decreased the angiotensin-converting enzyme 2 (ACE2) expression in the hearts from MetS rats. Ischemia activated the angiotensin-converting enzyme (ACE)/angiotensin II/angiotensin receptor 1 (AT1R) and angiotensin III/angiotensin IV/angiotensin receptor 4 (AT4R)-IRAP axes. Fenofibrate treatment prevented the damage due to ischemia in MetS rats by favoring the angiotensin-(1-7)/angiotensin receptor 2 (AT2R) axis and inhibiting the angiotensin III/angiotensin IV/AT4R-IRAP signaling pathway. Additionally, fenofibrate downregulated neprilysin expression and increased bradykinin production. These effects of PPAR-alpha activation were accompanied by a reduction in the size of the myocardial infarct and in the activity of serum creatine kinase. Thus, the regulation of the nonclassical axis of RAS forms part of a novel protective effect of fenofibrate in myocardial ischemia.

Bone Morphogenetic Protein-2 and Osteopontin Gene Expression in Epicardial Adipose Tissue from Patients with Coronary Artery Disease Is Associated with the Presence of Calcified Atherosclerotic Plaques.

PURPOSE: It has been proposed that the cardiovascular effects of obesity are related to epicardial adipose tissue (EAT), which seems to play an active role on the development and calcification of atherosclerotic plaques, but the mechanisms are still unknown. Therefore, the aim of this study was to determine whether the EAT expresses the genes of calcifying factors and whether such expression is associated with the body mass index (BMI) and with the presence of coronary artery calcium (CAC) in patients with coronary artery disease (CAD). PATIENTS AND METHODS: Forty-three patients with CAD were enrolled specifically for this study, and their CAC score and EAT volume were determined by computed tomography. As the group of comparison, 41 patients with aortic valve stenosis and CAC = 0 were included (control group). A representative subgroup of 16 CAD patients and 23 controls were selected to obtain EAT biopsies during the chirurgical procedure from the atrio-interventricular groove. The mRNA expression of bone morphogenetic protein-2 and -4 (BMP-2, BMP-4), osteopontin (OPN), osteonectin (ON), and osteoprotegerin (OPG) in EAT was determined by qPCR. RESULTS: The gene expression of OPN and BMP-2 was 70% and 52% higher in the EAT from CAD patients than that in controls, respectively, whereas the expression of OPG, ON, and BMP-4 was similar in both groups. The EAT volume positively correlated with OPG and with the BMI, suggesting a relationship of obesity with local higher expression of calcifying genes in the coronary territory. The logistic regression analysis showed that high levels of both OPN and BMP-2 increased about 6 and 8 times the odds of coronary calcification (CAC score > 0), respectively. CONCLUSION: EAT correlated with BMI and expressed the mRNA of calcifying genes but only OPN and BMP-2 expression was higher in CAD patients. Higher levels of both OPN and BMP-2 statistically determined the presence of calcium in coronary arteries of CAD patients.