Atorvastatin therapy in hypercholesterolemic patients suppresses cellular uptake of oxidized-LDL by differentiating monocytes

Effect of Statins on Patients With Osteoradionecrosis of the Jaw

BACKGROUND

Osteoradionecrosis of the jaw (ORN) is a late complication of radiation therapy. Radiation-induced fibrosis is the most likely mechanism for developing ORN, and statins are effective against radiation-induced fibrosis. However, no reports have indicated the direct effectiveness of statins in treating ORN.

PURPOSE

This study aimed to measure the association between statin exposure and ORN disease resolution.

STUDY DESIGN, SETTING, SAMPLE

This retrospective cohort study included patients with ORN diagnosed between January 2008 and December 2020 at the Hospital's Department of Oral and Maxillofacial Surgery. Patients who were immunocompromised or followed up for < 6 months were excluded.

PREDICTOR VARIABLE

The predictor variable was statin exposure, which was defined as the use of statins for dyslipidemia.

MAIN OUTCOME VARIABLE

The main outcome variable was ORN disease progression status (good prognosis). Patients who showed full recovery and improvement were included in the good prognosis group, and those who showed invariance and deterioration were included in the poor prognosis group.

COVARIATES

We analyzed the clinicodemographic including the age of onset, sex, history of smoking, alcohol consumption, history of chemotherapy, tumor site, association with dental treatment, location (maxilla or mandible), the time to ORN onset from radiation therapy, and stage of ORN, and treatment characteristics including hyperbaric oxygen therapy, long-term macrolide administration, and sequestrectomy.

ANALYSES

We analyzed the association between statin exposure or covariates and time to ORN improvement using bivariate and multivariate Cox regression. The significance level was set at P = .05.

RESULTS

We analyzed 102 patients, and the improvement rate was 32.4%. The favorable prognostic factors were statin exposure (adjusted hazard ratio [HR], 3.71; 95% confidence interval [CI], 1.62 to 8.50; P = .002), onset in the maxilla (HR, 2.15; 95% CI, 1.02 to 4.55; P = .045), and stage 1 of ORN (HR, 2.65; 95% CI, 1.20 to 5.83; P = .016).

CONCLUSION AND RELEVANCE

In this study, statin exposure, onset in the maxilla, and stage 1 of Lyons's classification were favorable prognostic factors for ORN. Although this study's findings were insufficient to recommend statin use for ORN, statins may be a novel and effective treatment for ORN.

Understanding the molecular mechanisms of statin pleiotropic effects

Statins represent the cornerstone of pharmacotherapy for the prevention of atherosclerotic cardiovascular disease. These medications not only reduce low-density lipoprotein cholesterol (LDL-C) via inhibition of 3-hydroxy-3-methylglutarate attached to CoA reductase, the key rate-limiting step in the cholesterol biosynthetic pathway, but also upregulate expression of the low-density lipoprotein receptor, improving serum clearance. Given LDL-C is a causal risk factor for the development of atherosclerosis, these complementary mechanisms largely explain why statin therapy leads to reductions in major adverse cardiovascular events. However, decades of basic and clinical research have suggested that statins may exert other effects independent of LDL-C lowering, termed pleiotropic effects, which have become a topic of debate among the scientific community. While some literature suggests statins may improve plaque stability, reduce inflammation and thrombosis, decrease oxidative stress, and improve endothelial function and vascular tone, other studies have suggested potential harmful pleiotropic effects related to increased risk of muscle-related side effects, diabetes, hemorrhagic stroke, and cognitive decline. Furthermore, the introduction of newer, non-statin LDL-C lowering therapies, including ezetimibe, proprotein convertase subtilisin/Kexin Type 9, and bempedoic acid, have challenged the statin pleiotropy theory. This review aims to provide a historical background on the development of statins, explore the mechanistic underpinnings of statin pleiotropy, review the available literature, and provide up to date examples that suggest statins may exert effects outside of LDL-C lowering and the cardiovascular system.

Genetic variants, gene expression, and soluble CD36 analysis in acute coronary syndrome: Differential protein concentration between ST-segment elevation myocardial infarction and unstable angina

Background

Atherosclerosis plays an important role in the pathophysiology of acute coronary syndrome (ACS). CD36 is a scavenger receptor involved in lipid metabolism. Some single‐nucleotide variants in the non‐coding region could indirectly alter the expression and the function of the protein.

Objective

The aim of this study was to investigate the gene and protein expression associated with CD36 variants (rs1194182;C > G; rs1049654;C > A, rs1334512;G > T, and rs3211892;G > A) in ACS patients from the western Mexican population.

Methods

We recruited 310 ACS patients and 308 subjects in the control group (CG). Genotyping was determined by TaqMan SNP genotyping assays. CD36 expression at the mRNA level was quantified by TaqMan gene expression assays. Soluble CD36 (sCD36) was measured by enzyme‐linked immunosorbent assay.

Results

We show that rs1194182G > C variant provides a protective effect with a 1.7‐fold lower susceptibility to develop ACS (p  = 0.03); however, this association was masked by diabetes and dyslipidemia. We observed a higher sCD36 concentration in patient with ST‐segment elevation myocardial infarction (STEMI) compared with patients with unstable angina (UA) (p  = 0.038). Likewise, in diabetic patients versus non‐diabetic (p < 0.001). We observed in patients an increase in CD36 mRNA expression (1.91 times higher) than in the CG (p  = 0.02).

Conclusion

The rs1194182 seems to be associated with diabetes in a risky manner, in ACS patients and protective for dyslipidemia in both groups. The concentration of sCD36 seems to be associated with the clinical spectrum of the ACS patients and the presence of diabetes, since patients with STEMI present significantly elevated level compared with UA.

Assessing the Impact of Colchicine on Coronary Plaque Phenotype After Myocardial Infarction with Optical Coherence Tomography: Rationale and Design of the COCOMO-ACS Study

Introduction

Recurrent event rates after myocardial infarction (MI) remain unacceptably high, in part because of the continued growth and destabilization of residual coronary atherosclerotic plaques, which may occur despite lipid-lowering therapy. Inflammation is an important contributor to this ongoing risk. Recent studies have shown that the broad-acting anti-inflammatory agent, colchicine, may reduce adverse cardiovascular events in patients post-MI, although the mechanistic basis for this remains unclear. Advances in endovascular arterial wall imaging have allowed detailed characterization of the burden and compositional phenotype of coronary plaque, along with its natural history and responsiveness to treatment. One such example has been the use of optical coherence tomography (OCT) to demonstrate the plaque-stabilizing effects of statins on both fibrous cap thickness and the size of lipid pools within plaque.

Methods

The Phase 2, multi-centre, double-blind colchicine for coronary plaque modification in acute coronary syndrome (COCOMO-ACS) study will evaluate the effect of colchicine 0.5 mg daily on coronary plaque features using serial OCT imaging in patients following MI. Recruitment for the trial has been completed with 64 participants with non-ST elevation MI randomized 1:1 to colchicine or placebo in addition to guideline recommended therapies, including high-intensity statins. The primary endpoint is the effect of colchicine on the minimal fibrous cap thickness of non-culprit plaque over an 18-month period.

Summary

The COCOMO-ACS study will determine whether addition of colchicine 0.5 mg daily to standard post-MI treatment has incremental benefits on high-risk features of coronary artery plaques. If confirmed, this will provide new mechanistic insights into how colchicine may confer clinical benefits in patients with atherosclerotic cardiovascular disease.

Trial Registration

ANZCTR trial registration number: ACTRN12618000809235. Date of trial registration: 11th of May 2018.

Effect of Si-Miao-Yong-An decoction on the differentiation of monocytes, macrophages, and regulatory T cells in ApoE-/- mice

ETHNOPHARMACOLOGICAL RELEVANCE

Si-Miao-Yong-An decoction (SMYAD) is a renowned traditional Chinese medicinal formula. SMYAD was originally recorded in the "Shi Shi Mi Lu", which was edited by medical scientist Chen Shi'duo during the Qing Dynasty. SMYAD has been traditionally used to treat thromboangiitis obliterans. At present, it is mainly used in clinical applications and research of cardiovascular diseases.

AIM OF THE STUDY

To explore the effects of SMYAD on the pathological changes of atherosclerosis (AS) and the differentiation of monocytes, macrophages, and regulatory T (Treg) cells in apolipoprotein E knockout (ApoE-/-) mice.

MATERIALS AND METHODS

Eight C57BL/6J mice, which were fed with normal diet for 16 weeks, were used as control group. Forty ApoE-/- mice were randomly divided into model group, atorvastatin group, SMYAD low-dose (SMYAD-LD) group, SMYAD medium-dose (SMYAD-MD) group, and SMYAD high-dose (SMYAD-HD) group. ApoE-/- mice were fed with western diet (WD) for 8 weeks, and the drugs were continuously administered for 8 weeks. The levels of serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were measured by the esterase method. Morphological changes of the aortic sinus in mice were observed by hematoxylin-eosin (HE) staining, the lipid infiltration of the aorta and aortic sinus were observed by oil red O staining, and the spleen index was calculated. The proportion of Ly6Chigh and Ly6Clow monocyte subsets, macrophages, and their M1 phenotype, as well as Treg cells in spleen were measured by flow cytometry. The expressions of cluster of differentiation 36 (CD36), scavenger receptor A1 (SRA1), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), F4/80, and fork head frame protein 3 (FOXP3) in aortic sinus were assessed by immunohistochemical staining. The serum levels of oxidized low density lipoprotein (ox-LDL), interleukin-1β (IL-1β), IL-18, transforming growth factor-β (TGF-β), and IL-10 were measured by enzyme-linked immunosorbent assays (ELISA).

RESULTS

Compared with the model group, the level of serum TC and LDL-C decreased in the SMYAD group, the pathological changes of aortic sinus decreased, and lipid infiltration of aorta and aortic sinus also decreased. These decreases were accompanied by a significant downregulation of CD36, SRA1, and LOX-1. Furthermore, the proportions of Ly6Chigh pro-inflammatory monocyte subsets, macrophages, and their M1 phenotypes in spleen decreased significantly, while the proportion of Treg cells increased. In addition, while the expression of F4/80 decreased, the expression of FOXP3 increased in the aorta sinus. The levels of serum pro-inflammatory factors IL-1β and IL-18 decreased.

CONCLUSIONS

SMYAD can improve the pathological changes associated with AS and can inhibit lipid deposition in ApoE-/- mice induced by WD diet. The likely mechanism is the inhibition of the differentiation and recruitment of monocytes and macrophages, the promotion of the differentiation and recruitment of Treg cells, as well as the reduction of the secretion of pro-inflammatory factors.

Improved lipid target level attainment in patients with peripheral artery disease

BACKGROUND

Patients with peripheral artery disease (PAD) fall under the category of a very high cardiovascular risk. Although, consequent lipid lowering therapy (LLT) is advised, only sparse data on attained target level in PAD exists.

OBJECTIVES

We aimed to analyse contemporary guideline recommendations for LLT in symptomatic PAD patients.

METHODS

monocentric, prospective, observational study involving 200 symptomatic PAD patients. Guideline target level attainment and LLT were analysed between 2017 and 2019.

RESULTS

Overall 78.5% of the patients were on statin therapy, mainly of high intensity with atorvastatin in 50% and rosuvastatin in 33% of the cases. Average statin dosage adjusted for simvastatin was 55 mg/d. Low density lipoproteincholesterol (LDL-C) was <1.8 mmol/L in 53% and <1.4 mmol/L in 34% of the cases. Mean LDL-C levels were at 1.85 ± 0.88 mmol/L. We observed no difference in the treatment and the target level attainment of patients with a stable PAD (intermittent claudication) or chronic critical PAD. However, patients with ≥1 vascular region affected (i.e. coronary and/or cerebrovascular) were treated more intensively and had lower LDL-C levels than patients with PAD alone.

CONCLUSION

It appears that there is more awareness and improvement of previously documented undertreatment of LDL-C levels in symptomatic PAD patients. Although statin treatment is initiated in the majority of patients, our findings call for a continuously intensified LLT in symptomatic PAD patients.

LOX-1, the Common Therapeutic Target in Hypercholesterolemia: A New Perspective of Antiatherosclerotic Action of Aegeline

BACKGROUND

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the major receptor for oxidized low-density lipoprotein (Ox-LDL) in the aorta of aged rats. Ox-LDL initiates LOX-1 activation in the endothelium of lipid-accumulating sites of both animal and human subjects of hypercholesterolemia. Targeting LOX-1 may provide a novel diagnostic strategy towards hypercholesterolemia and vascular diseases.

HYPOTHESIS

This study was planned to address whether aegeline (AG) could bind to LOX-1 with a higher affinity and modulate the uptake of Ox-LDL in hypercholesterolemia.

STUDY DESIGN

Thirty-six Wistar rats were divided into six groups. The pathology group rats were fed with high-cholesterol diet (HCD) for 45 days, and the treatment group rats were fed with HCD and aegeline/atorvastatin (AV) for the last 30 days. In vivo and in vitro experiments were carried out to assay the markers of atherosclerosis like Ox-LDL and LOX-1 levels. Histopathological examination was performed. Oil Red O staining was carried out in the IC-21 cell line. Docking studies were performed.

RESULTS

AG administration effectively brought down the lipid levels induced by HCD. The lowered levels of Ox-LDL and LOX-1 in AG-administered rats deem it to be a potent antihypercholesterolemic agent. Compared to AV, AG had a pronounced effect in downregulating the expression of lipids evidenced by Oil Red O staining. AG binds with LOX-1 at a higher affinity validated by docking.

CONCLUSION

This study validates AG to be an effective stratagem in bringing down the lipid stress induced by HCD and can be deemed as an antihypercholesterolemic agent.

Immunobiology of Atherosclerosis: A Complex Net of Interactions

Cardiovascular disease is the leading cause of mortality worldwide, and atherosclerosis the principal factor underlying cardiovascular events. Atherosclerosis is a chronic inflammatory disease characterized by endothelial dysfunction, intimal lipid deposition, smooth muscle cell proliferation, cell apoptosis and necrosis, and local and systemic inflammation, involving key contributions to from innate and adaptive immunity. The balance between proatherogenic inflammatory and atheroprotective anti-inflammatory responses is modulated by a complex network of interactions among vascular components and immune cells, including monocytes, macrophages, dendritic cells, and T, B, and foam cells; these interactions modulate the further progression and stability of the atherosclerotic lesion. In this review, we take a global perspective on existing knowledge about the pathogenesis of immune responses in the atherosclerotic microenvironment and the interplay between the major innate and adaptive immune factors in atherosclerosis. Studies such as this are the basis for the development of new therapies against atherosclerosis.

Paraoxonase 1 Activity, Polymorphism and Atherosclerosis Risk Factors in Patients Undergoing Coronary Artery Surgery

Background: Paraoxonase1 (PON1), an enzyme connected to high density lipoproteins (HDL) particles, plays an important role in protecting arteries against atherosclerosis. The serum activity and concentration of PON1 depends on several genetic polymorphisms as well as environmental factors. Materials and methods: Investigated population consisted of 71 patients aged 43–76 years with confirmed coronary heart disease (CHD). Established risk factors of CHD such as hypertension, elevated total cholesterol and LDL cholesterol (LDL-C), low HDL cholesterol (HDL-C), diabetes mellitus, obesity, smoking and premature CHD in family history were assessed. PON1 genotype for −108C/T promotor region was determined by polymerase chain reaction-restriction fragments length polymorphism (PCR–RFLP) method. Paraoxonase activity towards paraoxon and arylesterase activity towards phenyl acetate were measured spectrophotometrically. Results: Significant correlations between diabetes mellitus and paraoxonase activity (R = −0.264, p = 0.026) and between the premature coronary heart disease in family history and PON1 activity (R = −0.293, p = 0.013) were found. In multivariate analysis, PON1 paraoxonase activity was independently of confounding factors associated with diabetes (OR = 0.985; p = 0.024) and premature CHD in family history (OR = 0.983; p = 0.027). PON1 activity towards aryl acetate positively correlated with HDL-C level (R = 0.255, p = 0.032). In patients treated with statins, PON1 paraoxonase activity was significantly (p = 0.033) higher than in patients without treatment. Conclusions: In diabetic patients with CHD, paraoxonase activity is lower than in normoglycemic patients despite similar lipid profiles. Diabetes and positive family history in patients with overt CHD are associated with the serum PON1 activity, which might be an additional factor helpful in evaluating cardiovascular risk in this group of patients.

Effects of various doses of atorvastatin on vascular endothelial cell apoptosis and autophagy in vitro

Atorvastatin (Lipitor™) is a lipid‑lowering agent that is widely used in the treatment of cardiovascular diseases. Previous research has largely focused on its cholesterol‑lowering effects; however, a limited number of studies have investigated the actions of atorvastatin on vascular endothelial cells. In the present study, the effects of various doses of atorvastatin were investigated on human umbilical vein endothelial cells (HUVECs). HUVECs were treated with various concentrations of atorvastatin in serum‑free or serum‑containing medium, and alterations in HUVEC morphology were observed. Cell survival and necrosis rates were evaluated using sulforhodamine B and lactate dehydrogenase assays, respectively. In addition, the protein expression levels of cellular apoptosis and autophagy markers were detected using western blot analysis. The results revealed that HUVEC morphology was altered following treatment with various concentrations of atorvastatin. In addition, autophagy was demonstrated to be induced by atorvastatin treatment at all concentrations, whereas high concentrations appeared to induce apoptosis and suppress the survival of HUVECs. In conclusion, the results of the present study suggested that various doses of atorvastatin may exert differential effects on HUVECs, and high doses may suppress angiogenesis. Therefore, atorvastatin may present a novel potential anti‑tumor therapeutic strategy. However, further studies are required to fully elucidate the association between the dose of atorvastatin and its clinical outcome.

Association between Q192R polymorphism in the PON1 gene and statin responses in cardiac patients

Introduction

Paraoxonases are a group of different forms enzymes that consist of three non-similar isoforms, PON1, PON2 and PON3, which are located near to each other on the long arm of chromosome7. This study aims to investigate the association of a Q192R polymorphism of PON1 gene and statin response in patients with ischemic heart disease with dyslipidemia.

Methods

The studied population included three hundred patients with coronary artery disease with dyslipidemia who were prescribed statins. Total lipid profile was measured in these patients both before and after approximately 6 months of treatment. Q192R polymorphism of PON1 gene was assessed by real-time PCR.

Results

There were no significant differences in baseline lipid levels according to different genotypes in all studied casesof Q192R (rs662) polymorphism. HDL-C goals were attained less often in patients with RR homozygosity than in Q allele carriers. Analysis by univariate logistic regression confirmed that QQ/QR carriers had an increased chance of attaining HDL-C goals.

Conclusion

This study shows that the Q192R polymorphism of PON1gene has important role in interindividual variety in accomplishment of HDL-C goals in response to statins.

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The studied 300 patients with ischemic heart disease with dyslipidemia who were prescribed statins.

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Q192R polymorphism of PON1 gene was assessed by real-time PCR.

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This study shows that the Q192R polymorphism of PON1 gene may play a role in achievement of HDL-C goals in response to statins.

Antioxidative activity of high-density lipoprotein (HDL): Mechanistic insights into potential clinical benefit

Uptake of low-density lipoprotein (LDL) particles by macrophages represents a key step in the development of atherosclerotic plaques, leading to the foam cell formation. Chemical modification of LDL is however necessary to induce this process. Proatherogenic LDL modifications include aggregation, enzymatic digestion and oxidation. LDL oxidation by one-electron (free radicals) and two-electron oxidants dramatically increases LDL affinity to macrophage scavenger receptors, leading to rapid LDL uptake and fatty streak formation. Circulating high-density lipoprotein (HDL) particles, primarily small, dense, protein-rich HDL3, provide potent protection of LDL from oxidative damage by free radicals, resulting in the inhibition of the generation of pro-inflammatory oxidized lipids. HDL-mediated inactivation of lipid hydroperoxides involves their initial transfer from LDL to HDL and subsequent reduction to inactive hydroxides by redox-active Met residues of apolipoprotein A-I. Several HDL-associated enzymes are present at elevated concentrations in HDL3 relative to large, light HDL2 and can be involved in the inactivation of short-chain oxidized phospholipids. Therefore, HDL represents a multimolecular complex capable of acquiring and inactivating proatherogenic lipids. Antioxidative function of HDL can be impaired in several metabolic and inflammatory diseases. Structural and compositional anomalies in the HDL proteome and lipidome underlie such functional deficiency. Concomitant normalization of the metabolism, circulating levels, composition and biological activities of HDL particles, primarily those of small, dense HDL3, can constitute future therapeutic target.

Effects of dyslipidaemia on monocyte production and function in cardiovascular disease

Monocytes are heterogeneous effector cells involved in the maintenance and restoration of tissue integrity. Monocytes and macrophages are involved in cardiovascular disease progression, and are associated with the development of unstable atherosclerotic plaques. Hyperlipidaemia can accelerate cardiovascular disease progression. However, monocyte responses to hyperlipidaemia are poorly understood. In the past decade, accumulating data describe the relationship between the dynamic blood lipid environment and the heterogeneous circulating monocyte pool, which might have profound consequences for cardiovascular disease. In this Review, we explore the updated view of monocytes in cardiovascular disease and their relationship with macrophages in promoting the homeostatic and inflammatory responses related to atherosclerosis. We describe the different definitions of dyslipidaemia, highlight current theories on the ontogeny of monocyte heterogeneity, discuss how dyslipidaemia might alter monocyte production, and explore the mechanistic interface linking dyslipidaemia with monocyte effector functions, such as migration and the inflammatory response. Finally, we discuss the role of dietary and endogenous lipid species in mediating dyslipidaemic responses, and the role of these lipids in promoting the risk of cardiovascular disease through modulation of monocyte behaviour.

Macrophage-mediated cholesterol handling in atherosclerosis

Formation of foam cells is a hallmark at the initial stages of atherosclerosis. Monocytes attracted by pro-inflammatory stimuli attach to the inflamed vascular endothelium and penetrate to the arterial intima where they differentiate to macrophages. Intimal macrophages phagocytize oxidized low-density lipoproteins (oxLDL). Several scavenger receptors (SR), including CD36, SR-A1 and lectin-like oxLDL receptor-1 (LOX-1), mediate oxLDL uptake. In late endosomes/lysosomes of macrophages, oxLDL are catabolysed. Lysosomal acid lipase (LAL) hydrolyses cholesterol esters that are enriched in LDL to free cholesterol and free fatty acids. In the endoplasmic reticulum (ER), acyl coenzyme A: cholesterol acyltransferase-1 (ACAT1) in turn catalyses esterification of cholesterol to store cholesterol esters as lipid droplets in the ER of macrophages. Neutral cholesteryl ester hydrolases nCEH and NCEH1 are involved in a secondary hydrolysis of cholesterol esters to liberate free cholesterol that could be then out-flowed from macrophages by cholesterol ATP-binding cassette (ABC) transporters ABCA1 and ABCG1 and SR-BI. In atherosclerosis, disruption of lipid homoeostasis in macrophages leads to cholesterol accumulation and formation of foam cells.

Effects of established hypolipidemic drugs on HDL concentration, subclass distribution, and function

The knowledge of an inverse relationship between plasma high-density lipoprotein cholesterol (HDL-C) concentrations and rates of cardiovascular disease has led to the concept that increasing plasma HDL-C levels would be protective against cardiovascular events. Therapeutic interventions presently available to correct the plasma lipid profile have not been designed to specifically act on HDL, but have modest to moderate effects on plasma HDL-C concentrations. Statins, the first-line lipid-lowering drug therapy in primary and secondary cardiovascular prevention, have quite modest effects on plasma HDL-C concentrations (2-10%). Fibrates, primarily used to reduce plasma triglyceride levels, also moderately increase HDL-C levels (5-15%). Niacin is the most potent available drug in increasing HDL-C levels (up to 30%), but its use is limited by side effects, especially flushing.The present chapter reviews the effects of established hypolipidemic drugs (statins, fibrates, and niacin) on plasma HDL-C levels and HDL subclass distribution, and on HDL functions, including cholesterol efflux capacity, endothelial protection, and antioxidant properties.

Endothelial progenitor cells in diabetic patients with myocardial infarction - can statins improve their function?

The effect of statins on endothelial progenitor cells (EPCs) function derived from diabetic patients (DMpts) with acute myocardial infarction (AMI) is unknown. In this study we assess the response of early and late EPCs from diabetic versus non-diabetic patients (NDMpts) with AMI to statins. EPCs were obtained from 10 diabetic and 10 age-matched non-diabetic male patients with AMI. For each patient, cultures of early and late EPCs were performed under 4 different conditions: normal glucose concentration (control); high glucose concentration; normal glucose concentration with atorvastatin supplementation and normal glucose concentration with pravastatin supplementation. To compare the effect of these treatments on EPC function in DMpts versus NDMpts, we performed in vitro: EPC colony-forming units (CFU) assay; cell cycle analysis; viability assessment and expression of the surface markers CXCR4, CD133, CD34 and KDR. Under control conditions, CFU numbers were reduced in DMpts-derived EPCs when compared to those of NDMpts (1.4±0.8 vs 2.6±1.2 CFU/well, P=0.021). When early EPCs from DMpts were cultured in the presence of statins, CFU capacity was restored, surmounting that of NDMpts under control conditions. Statins significantly improved viability of early EPCs and delayed the onset of late EPCs senescence, even in cells from DMpts. In addition, statins induced approximately a 2-fold increase in the proportion of late EPCs in S-phase of the cell cycle (P<0.05). Statins have a beneficial effect on both early and late EPCs from DMpts with AMI. Despite the functional impairment of EPCs from DMpts, they exhibit similar responsiveness to statins as equivalent cells from NDMpts.

Nanoparticulate carrier system: a novel treatment approach for hyperlipidemia

Hyperlipidemia is a prevailing risk factor that leads to development and progression of atherosclerosis and consequently cardiovascular diseases. Several antihyperlipidemic drugs are having various disadvantages such as low water solubility and poor bioavailabilty due to presystemic gastrointestinal clearance. Thus, there is a considerable need for the development of efficient delivery methods and carriers. This review focuses on the importance and role of various nanoparticulate systems as carrier for antihyperlipidemic drugs in the treatment of hyperlipidemia. Some nanoparticle technology-based products are approved by FDA for effective treatment of hyperlipidemia, namely Tricor® by Abbott Laboratories (Chicago, IL, USA) and Triglide® by Skye Pharma (London, UK). Efforts to address each of these issues are going on, and should remain the focus on the future studies and look forward to many more clinical products in the future.

Zerumbone Suppresses Phorbol Ester-Induced Expression of Multiple Scavenger Receptor Genes in THP-1 Human Monocytic Cells

Unregulated uptake of oxidized low-density lipoproteins (ox-LDL) via macrophage scavenger receptors (SRs), such as lectin-like ox-LDL receptor-1 (LOX-1), is a key event in atherosclerosis. In the present study, we used differentiated Caco-2 cells as a model of the human small intestine to evaluate the suppressive effects of 16 traditional food items selected from Okinawa on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced LOX-1 mRNA expression in THP-1 human monocyte-like cells. Three Zingiberaceae plants, Curcuma aromatica Salisbury, Curcuma longa L., and Zingiber zerumbet Smith, markedly suppressed that expression. When added to the apical sides of Caco-2 monolayers, zerumbone, a sesquiterpene from Z. zerumbet Smith, was found to permeate into the basolateral medium as an intact structure in a time-dependent manner. alpha-Humulene, a structural analog of zerumbone lacking the alpha,beta-unsaturated carbonyl group, did not suppress LOX-1 mRNA expression, indicating that its electrophilic moiety might play pivotal roles in its activities. Further, zerumbone attenuated the expression of SR-A, SR-PSOX, and CD36, but not that of CD68 or CLA-1, leading to a blockade of DiI-acLDL uptake, while it also inhibited the transcriptional activities of activator protein-1 and nuclear factor-kappaB. Together, our results indicate that zerumbone is a potential phytochemical for regulating atherosclerosis with reasonable action mechanisms.

The good and bad effects of statins on insulin sensitivity and secretion

AIMS

Statins are the main lipid-lowering treatment in both primary and secondary prevention populations. Whether statins deteriorates glycemic control, predisposing to the onset of diabetes mellitus has been a matter of recent concern. Statins may accelerate progression to diabetes via molecular mechanisms that impact insulin sensitivity and secretion. In this review, we debate the relative effect of statins in driving insulin resistance and the impairment of insulin secretion.

METHODS

Narrative overview of the literature synthesizing the findings of literature was retrieved from searches of computerized databases, hand searches, and authoritative texts employing the key words "Statins", "Randomized Clinical Trial", "Insulin sensitivity", "Insulin resistance", "Insulin Secretion", "Diabetes Mellitus" alone and/or in combination.

RESULTS

The weight of clinical evidence suggests a worsening effect of statins on insulin resistance and secretion, anyway basic science studies did not find a clear molecular explanation, providing conflicting evidence regarding both the beneficial and the adverse effects of statin therapy on insulin sensitivity.

CONCLUSIONS

Although most of the clinical studies suggest a worsening of insulin resistance and secretion, the cardiovascular benefits of statin therapy outweigh the risk of developing insulin resistance, thus the data suggest the need to treat dyslipidemia and to make patients aware of the possible risk of developing type 2 diabetes or, if they already are diabetic, of worsening their metabolic control.

Highly upregulated expression of CD36 and MSR1 in circulating monocytes of patients with acute coronary syndromes

Acute Coronary Syndromes (ACS) are a group of disorders caused by the significant reduction of circulation in coronary arteries. The most common reason of the dysfunction is a blood clot formed in place of plaque rupture. The role of scavenger receptors in development and progression of atherosclerosis has been confirmed in many animal experiments, however the knowledge about contribution of the receptors in the development of ACS symptoms in humans still remains insufficient. The aim of this work was to define the expression of two scavenger receptors: CD36 and MSR1 in monocytes of patients with ACS after the onset of symptoms and after the 6 months of treatment. The analysis of CD36 and MSR1 expression was carried out with the use of real-time PCR and flow cytometry. Analyses of lipid and glucose concentration in blood and the level of inflammatory markers in plasma were performed additionally for all ACS patients. All data obtained during the research were analyzed using statistical tests, such as Mann Whitney test, Wilcoxon test, or correlation. In all patients with symptoms of ACS the amount of CD36 and MSR1 mRNA in circulating monocytes, as well as the density of both receptors on the cells surface was significantly higher. Re-analysis of subjects after 6 months of treatment, showed a significant decrease in the CD36 and MSR1 expression in all patients who received atorvastatin. The results of presented studies demonstrate that both investigated receptors are involved in the development and/or progression of ACS.

Pravastatin and simvastatin improves acetylsalicylic acid-mediated in vitro blood platelet inhibition

BACKGROUND

Insight into the pathophysiology of atherothrombosis indicates that an integrated risk factor approach, focusing particularly on the management of dyslipidaemia (with statins) and thrombosis (with ASA), may constitute an optimal therapeutic approach. We investigated whether pravastatin, simvastatin and atorvastatin may directly modulate under in vitro conditions the reactivity of blood platelets originating from healthy volunteers. In addition, we analysed the influence of statins on the platelet sensitivity to ASA under such conditions.

MATERIALS AND METHODS

We monitored collagen- or ADP-induced platelet aggregation, CD36, PAC-1 and CD62 expression on platelet surface and thromboxane generation after incubation with pravastatin, simvastatin, atorvastatin and/or ASA.

RESULTS

The incubation of whole blood with simvastatin and pravastatin significantly decreased CD36 expression. In the presence of 50 μM ASA, simvastatin and pravastatin significantly reduced the PAC-1 expression (30% reduction for simvastatin, P < 0·01, and 15% reduction for pravastatin, P < 0·01), platelet aggregation (20% reduction for both statins, P < 0·01) and thromboxane generation (35% reduction for simvastatin, P < 0·001, and 30% reduction for pravastatin, P < 0·001) compared to ASA alone. Atorvastatin changed neither baseline platelet aggregation nor ASA-mediated platelet inhibition.

CONCLUSIONS

Our results suggested that statins may directly interact with platelet membranes or may modulate a signalling pathway in platelets (the pleiotropic effects of statins). It is possible that the statin effect on CD36 and ASA-mediated protein acetylation can be reached by the modulation of a distribution or a function of membrane-associated proteins. Further studies are certainly needed to better elucidate the mechanism(s) underlying the statins' effects on platelet sensitivity to ASA.

The urokinase system in the pathogenesis of atherosclerosis

Atherogenesis refers to the development of atheromatous plaques in the inner lining of the arteries. These atherosclerotic lesions are characterized by accumulation of monocyte-derived macrophage-foam cells loaded with cholesterol, which eventually undergo apoptotic death, leading finally to formation of the necrotic core of the plaque. Atheroma formation also involves the recruitment of smooth muscle cells (SMC) from the media into the intima, where they proliferate and form the neointima in a process called "remodeling". Cells in the advanced atherosclerotic plaques express high levels of the serine protease urokinase-type plasminogen activator (uPA) and its receptor (uPAR). uPA is a multi-functional multi-domain protein that is not only a regulator of fibrinolysis, but it is also associated with several acute and chronic pathologic conditions. uPA mediate the extracellular matrix (ECM) degradation, and plays a pivotal role in cell adhesion, migration and proliferation, during tissue remodeling. On cell surface uPA binds to the high affinity urokinase receptor, providing a strictly localized proteolysis of ECM proteins. The uPA/uPAR complex also activates intracellular signaling, thus regulating cellular function. An imbalance in the uPA/uPAR system leads to dis-orders in tissue structure and function. This review summarizes recent progress in understanding the role and mechanisms of the uPA/uPAR system in atherogenesis.

Paraoxonase 1 (PON1) inhibits monocyte-to-macrophage differentiation

OBJECTIVE

To analyze paraoxonase 1 (PON1) effect on monocyte-to-macrophage differentiation.

METHODS AND RESULTS

THP-1 monocytic cell-line and mouse peritoneal macrophages (MPM) were studied. Markers for monocytes differentiation included: morphological changes, CD11b and CD36 expression, and cellular oxidative stress. PON1KO MPM were more differentiated than control C57BL/6 MPM. Intraperitoneal injection of recombinant PON1 (rePON1) to C57BL/6 or to PON1KO mice significantly increased serum, MPM, and tissues PON1 activities. These effects were associated with a significant decrease in CD11b in C57BL/6 and PON1KO MPM (by 21% and 35%, respectively), in CD36 (by 35% and 38%, respectively), and in cellular total peroxides content (by 18% and 20%, respectively). rePON1 also significantly inhibited CD11b and CD36 expression, and cellular total peroxides during PMA-induced THP-1 monocytes differentiation, by 68%, 56% and 53%, respectively. Similar effects were observed upon using reconstituted HDL (rHDL) +rePON1, or human HDL +rePON1, in comparison to rHDL or to human HDL, as well as, HDL from C57BL/6 vs. PON1KO mice. Inhibition of monocyte-to-macrophage differentiation was demonstrated also by several dietary antioxidants such as vitamin E, gallic acid, or punicalagin (the major polyphenol in pomegranate). Whereas NADPH oxidase was not involved in PON1 anti-differentiation effect, mitochondrial complex I could be involved, as rotenone (complex I inhibitor) significantly decreased (by 77%) the expression of CD11b during THP-1 differentiation. Finally, blocking PON1 sulfhydryl group with N-ethylmalemide significantly attenuated PON1 inhibitory effect on THP-I monocyte-to-macrophage differentiation.

CONCLUSION

HDL-associated PON1 inhibits monocyte-to-macrophage differentiation, and this effect could be related to PON1 peroxidase-like activity which involves its free sulfhydryl group.

The effects of atorvastatin and rosuvastatin on oxidative stress in diabetic patients

AIM

Diabetes is associated with abnormalities in lipid profile and increased oxidative stress. Statins are preferred agents in diabetic patients due to their antioxidant and LDL-C lowering effects. This study is designed to compare the effects of atorvastatin and rosuvastatin on low density lipoprotein cholesterol (LDL-C), lipid hydroperoxide (LOOH), total oxidant status (TOS) and total antioxidant capacity (TAC) in diabetic patients with hyperlipidemia.

MATERIALS AND METHODS

Sixty two patients who have type 2 diabetes mellitus with serum LDL levels more than 100mg/dL were randomly assigned to receive atorvastatin 20mg (n=31) or rosuvastatin 10mg (n=31). Blood tests were performed at the beginning of the study and after three months.

RESULTS

There were no statistically significant differences in the pre- and after treatment levels of the LDL-C between groups. TAC values were increased in both groups and statistically significant in the former group (p=0.007). There was no difference between the change percentages ((after treatment TAC-pretreatment TAC)/pretreatment level) of TAC between two treatment groups. The effects of two drugs on the other oxidative parameters were not significantly different.

CONCLUSION

Both atorvastatin and rosuvastatin may be helpful in reducing increased oxidative stress in diabetic patients with hyperlipidemia.

Effect of atorvastatin therapy on oxidant-antioxidant status and atherosclerotic plaque formation

Background:

The aim of this study was to determine the oxidant–antioxidant status and lipid peroxidation products, as well as paraoxonase and atherosclerotic plaque formation, in a hypercholesterolemic atherosclerosis rabbit model to investigate the effects of atorvastatin in the atherosclerotic process.

Methods:

Forty male New Zealand rabbits were divided into four groups, ie, a control group receiving standard pellets, a group receiving atorvastatin therapy, a hypercholesterolemic group receiving an atherogenic diet, and a group receiving both an atherogenic diet and atorvastatin.

Results:

The atherogenic diet increased the levels of low-density lipoprotein (LDL) thiobarbituric acid reactive substances (1.84 vs 3.79 nmol/mg protein) and LDL-conjugated diene (147 vs 318 μmol/mg protein) after induction of oxidation by Cu²⁺, despite an increase of superoxide dismutase activity. Treatment with atorvastatin limited LDL oxidation significantly (LDL thiobarbituric acid reactive substances 2.19 nmol/mg protein, LDL-conjugated diene 222 μmol/mg protein). Paraoxonase, which prevents LDL oxidation and inactivates LDL-derived oxidized phospholipids, showed a pronounced decrease in the group receiving the atherogenic diet (110 U/L to 28 U/L), and atorvastatin treatment increased paraoxonase activity. Histological examination of arcus aorta tissues from the hypercholesterolemic group showed abundant plaque formation surrounding and obstructing the lumen, whereas treatment with atorvastatin prevented or limited plaque formation, keeping the plaque thin and localized.

Conclusion:

Atorvastatin has dramatic antiatherosclerotic effects, part of which seems to be due to the antioxidant features of the parent drug and/or its metabolites, favoring inhibition of LDL oxidation.

Cytokines, macrophage lipid metabolism and foam cells: implications for cardiovascular disease therapy

Cardiovascular disease is the biggest killer globally and the principal contributing factor to the pathology is atherosclerosis; a chronic, inflammatory disorder characterized by lipid and cholesterol accumulation and the development of fibrotic plaques within the walls of large and medium arteries. Macrophages are fundamental to the immune response directed to the site of inflammation and their normal, protective function is harnessed, detrimentally, in atherosclerosis. Macrophages contribute to plaque development by internalizing native and modified lipoproteins to convert them into cholesterol-rich foam cells. Foam cells not only help to bridge the innate and adaptive immune response to atherosclerosis but also accumulate to create fatty streaks, which help shape the architecture of advanced plaques. Foam cell formation involves the disruption of normal macrophage cholesterol metabolism, which is governed by a homeostatic mechanism that controls the uptake, intracellular metabolism, and efflux of cholesterol. It has emerged over the last 20 years that an array of cytokines, including interferon-γ, transforming growth factor-β1, interleukin-1β, and interleukin-10, are able to manipulate these processes. Foam cell targeting, anti-inflammatory therapies, such as agonists of nuclear receptors and statins, are known to regulate the actions of pro- and anti-atherogenic cytokines indirectly of their primary pharmacological function. A clear understanding of macrophage foam cell biology will hopefully enable novel foam cell targeting therapies to be developed for use in the clinical intervention of atherosclerosis.

Synthesis and structure-activity relationship of N-(2-arylethyl) isoquinoline derivatives as human scavenger receptor CD36 antagonists

By using human scavenger receptor CD36 as the target, twenty-five N-(2-arylethyl) isoquinoline derivatives were designed, synthesized and evaluated for their antagonistic activities for CD36-oxidatively low density lipoprotein (oxLDL) binding. The primary analysis of structure-activity relationship (SAR) indicated a methoxyl at the 7-position and a hydroxyl at the 6- or 8-position could afford good activities. Among these analogs, compounds 7e and 7t showed the potential CD36 antagonistic activities with IC(50) values of 0.2 and 0.8 μg/mL, respectively. Furthermore, both of them could effectively inhibit oxLDL uptake in insect Sf9 cells overexpressing human CD36, and thus have been selected for further investigation. We consider N-(2-arylethyl) isoquinoline analogs to be a family of novel CD36 antagonists.

Serum soluble CD36, assessed by a novel monoclonal antibody-based sandwich ELISA, predicts cardiovascular mortality in dialysis patients

AIM

Accelerated atherosclerosis is a characteristic feature of chronic kidney disease (CKD). CD36 is a scavenger receptor which contributes to foam cell formation, an early crucial step in atherosclerosis development. Recently, a soluble form of CD36 (sCD36) has been discovered. The aim of the study was to develop an ELISA method for quantitative sCD36 evaluation and to measure it in a cohort of CKD stage 5 patients.

METHOD

A novel monoclonal antibody-based sandwich ELISA for sCD36 evaluation was developed and verified by repeated optimization procedures. Serum concentration of sCD36 was then analyzed in a cohort of 228 CKD stage 5 patients prior to dialysis initiation. Additionally, samples from a control group of 73 healthy, age and gender-matched subjects were evaluated.

RESULTS

The novel CD36 ELISA assay had a recovery of at least 90%, and intra- and inter-assay variability of 6 and 11%, respectively. Concentration of serum sCD36 in CKD patients was significantly increased as compared to controls, and associated with the use of HMG-CoA reductase inhibitors (statins) and the presence of diabetes mellitus (DM). Patients above the 75th percentile of sCD36 concentration were at increased risk of 3-year cardiovascular mortality, as compared to the rest of the cohort [HR 2.85 (1.09-7.59) p=0.03].

CONCLUSION

For the first time, sCD36 was assessed quantitatively in a group of patients and showed associations with DM, CKD, and statin use. Furthermore, the concentration of sCD36 predicted cardiovascular mortality in CKD stage 5 patients.

Modulating effect of atorvastatin on paraoxonase 1 activity in type 2 diabetic Egyptian patients with or without nephropathy

The aim of this study was to investigate the modulating effect of atorvastatin on serum paraoxonase 1 enzyme (PON1) activity in type 2 diabetic Egyptian patients with or without nephropathy. The present study was carried out on the following groups: control group, which consisted of 30 healthy persons; Group I, which consisted of 20 type 2 diabetic patients without nephropathy; and Group II, which consisted of 20 type 2 diabetic patients with nephropathy. All the patients selected were under an antidiabetic regimen of insulin, and patients receiving antihypertensive agents were excluded from the follow-up study to avoid drug interaction fallacies. Twenty-two patients (15 without nephropathy and seven with nephropathy) received atorvastatin in individually adjusted oral dosage (range 10-20 mg) once per day for 12 weeks. All cases were subjected to thorough clinical examination and history taking and measurement of serum levels of PON1 activity, malondialdehyde (MDA), glutathione reductase activity, fasting glucose, total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), urea, and creatinine. Urine samples were collected for determination of proteinuria. The obtained results showed that PON1 activity and HDL significantly decreased and fasting glucose significantly increased in Group I and Group II when compared to the control group, with significant difference in their levels between Group II and Group I. MDA, total cholesterol, and LDL levels significantly increased and glutathione reductase activity significantly decreased in Group I and Group II when compared to the control group. Urea, creatinine, and proteinuria levels showed significant increase in Group II when compared to the control group and Group I, with nonsignificant difference between control group and Group I. Atorvastatin therapy caused a significant increase in PON1 activity, and serum levels of MDA and glutathione reductase activity were significantly decreased and increased, respectively. Also, total cholesterol, triglyceride and LDL-cholesterol levels were significantly reduced with a significant increase in HDL-cholesterol levels. There was a significant modest reduction in serum urea and creatinine levels as well as in proteinuria level. Fasting glucose level was significantly reduced under the antidiabetic regimen of insulin through the follow-up period. PON1 activity showed a significant negative correlation with glucose and LDL, and a significant positive correlation with HDL in all the studied groups. It could be concluded that atorvastatin with its pleiotropic effects could provide optimal therapeutic intervention to control not only dyslipidemia, but also oxidative stress status with consequent improvement in the course of type 2 diabetes and diabetic nephropathy. More specifically, restoration of PON1 activity by atorvastatin opens a window to investigate other drugs that could provide a new adjuvant therapeutic line for better control of diabetes and diabetic nephropathy. Further research is also recommended to study the distribution of PON1 genetic polymorphism among the Egyptian population to explain the variability in its activity and its relationship with other factors that associate diabetes and its complications.

Atorvastatin downregulates monocyte CD36 expression, nuclear NFkappaB and TNFalpha levels in type 2 diabetes

AIM

Type 2 diabetes increases the risk for cardiovascular disease, and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) reduce cardiovascular events in these patients. The benefits of statin therapy cannot be explained only by the lipid-lowering effect. The aim of this study was to test the effect of atorvastatin therapy on CD36 scavenger receptor expression, nuclear factor-kappaB (NFkappaB) levels and markers of inflammation (C-reactive protein, CRP, Tumor Necrosis Factor-alpha, TNF-alpha) in circulating monocytes from diabetic patients.

METHODS

Twenty-two type 2 diabetic patients were treated for 8 weeks with atorvastatin (20 mg/day). At baseline and after treatment a blood sample was collected for measurement of glucose, lipid profile (total cholesterol, HDL, LDL cholesterol, triglycerides), glycated hemoglobin (HbA1c), CRP and for isolation of monocytes.

RESULTS

Atorvastatin decreased total (p<0.0001) and LDL (p<0.01), and incresased HDL choles-terol (p<0.02). CD36 surface protein expression (anti-CD36 fluorescein isothiocyanate-FITC) was reduced in circulating monocytes after atorvastatin therapy (p<0.02) while immunoblot analysis showed reduced nuclear and increased cytoplasm NFkappaB levels (p<0.05). Finally, TNFalpha production in lipopolysaccharide-activated monocytes from patients treated with atorvastatin was reduced (p<0.05).

CONCLUSION

These results suggest that atorvastatin therapy, beside lowering serum cholesterol levels, could exert anti-atherogenic and anti-inflammatory effects in type 2 diabetic patients.

Basic Science Review Section: Statin Therapy—Part II: Clinical Considerations for Cardiovascular Disease

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, commonly known as statins, are the medical treatment of choice for hypercholesterolemia. In addition to achieving a therapeutic decrease in serum cholesterol levels, statin therapy appears to promote pleiotropic effects that are independent of changes in serum cholesterol. These cholesterol lowering and pleiotropic effects are beneficial not only for the coronary circulation, but for the myocardium and peripheral arterial system as well. Patients receiving statin therapy must be carefully monitored, however, as statins potentially have harmful side effects and drug interactions. This article is part II of a 2-part review, and it focuses on the clinical aspects of statin therapy in cardiovascular disease.

Ezetimibe therapy and its influence on oxidative stress and fibrinolytic activity

OBJECTIVE

The effect of ezetimibe on blood lipids, oxidative stress, and fibrinolytic activity in hyperlipidemic patients was investigated after three months of therapy.

METHODS

Thirty hyperlipidemic patients were treated for twelve weeks with ezetimibe 10 mg/day. A healthy control group with matching age and gender was also included. Fasting blood glucose, lipid parameters, paraoxonase (PON1), protein carbonyl (PCO), oxidized LDL (oxLDL), 8-isoprostane (ISOPR), total antioxidant capacity (TAC) levels, tissue-type plasminogen activator (tPA), plasminogen activator inhibitor type-1 (PAI-1), and PAI-1/t-PA levels were evaluated.

RESULTS

Ezetimibe therapy for twelve weeks led to changes in lipid profile in accordance with the literature. Fibrinolytic activity parameters, PAI-1/tPA and tPA-1 decreased, whereas PAI-1 levels did not change significantly. Antioxidant parameters, serum PON1 activity, and TAC levels increased significantly compared with the basal values. Oxidant parameters, oxLDL, ISOPR, and PCO (which is an indicator of oxidative protein damage) decreased significantly after therapy.

CONCLUSIONS

Ezetimibe therapy has beneficial effects on fibrinolytic activity and homeostasis between oxidant and antioxidant activity in hyperlipidemic patients This may be through lowering lipid levels or other mechanisms such as decreasing insulin resistance and the pleiotropic effects of the drug.

Inhibition of foam cell formation using a soluble CD68-Fc fusion protein

The appearance of lipid-rich foam cells is a major feature of vulnerable atherosclerotic plaque formation. The transformation of macrophages into foam cells results from excessive uptake of cholesterol-rich particles by scavenger receptors such as CD68. We cloned a CD68-Fc immunoadhesin, a fusion protein consisting of the extracellular domain of the human CD68 and a human Fc domain, and investigated the function in vitro. Specific binding of CD68-Fc to OxLDL with an affinity of 10 nmol/L was determined by surface plasmon resonance and increased binding to lipid-rich human and ApoE(-/-) mice plaque tissue. This was confirmed both by immunohistochemical staining of CD68-Fc-treated paraffin sections from human plaques and by ELISA-based quantification of CD68-Fc binding to human atherosclerotic plaque extracts. In an in vitro model of macrophage/foam cell formation, CD68-Fc reduced foam cell formation significantly. This was caused both by interference of CD68-Fc with OxLDL uptake into macrophages and platelets and by the inhibition of platelet/OxLDL phagocytosis. Finally, expression of metalloproteinases by macrophages/foam cells was inhibited by CD68-Fc. In conclusion, CD68-Fc seems to be a promising new tool for preventing macrophage/foam cell formation. Thus, CD68-Fc might offer a novel therapeutic strategy for patients with acute coronary syndrome by modulating the generation of vulnerable plaques.

Benefits and difficulties in measuring HDL subfractions and human paraoxonase-1 activity during statin treatment

Dyslipidaemia including decreased high density lipoprotein cholesterol concentration is one of several factors that have been implicated in increased cardiovascular risk. Since their introduction in the 1980s, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have emerged as the one of the best-selling class of medications to date, with numerous trials demonstrating powerful efficacy in preventing cardiovascular diseases. Although statins have been shown to modestly raise or not alter HDL-cholesterol, their effect on HDL subfractions and on HDL-associated enzymes including human paraoxonase-1 (PON1) has not yet been fully explored. This review summarizes the currently available data on the effect of statins on HDL subfractions and on PON1 activity with a particular emphasis on the clinical relevance of these effects. Moreover, methodological problems of HDL subfraction and PON1 activity determinations are also discussed.

Evidence for statin therapy in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age group that is associated with increased cardiovascular risk. In addition to its lipid-lowering effects, statin therapy has shown been shown to have beneficial pleiotropic effects that may contribute to their reduction in cardiovascular morbidity and mortality. In this review, the effect of statins on PCOS is discussed with reference to the underlying potential mechanism of action.

Atorvastatin increases expression of low-density lipoprotein receptor mRNA in human circulating mononuclear cells

1. 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) inhibitors, or statins, are commonly used to lower plasma cholesterol levels. HMGCR and the low-density lipoprotein (LDL) receptor (LDLR) are of central importance to cholesterol homeostasis and yet there is a paucity of data on the effect of statins on the regulation of the LDLR and HMGCR in humans. 2. In the present study, we examined the effect of atorvastatin on the expression of HMGCR, LDLR and LDLR-related protein (LRP) mRNA in circulating mononuclear cells. Twelve human volunteers were treated with atorvastatin, 20 mg/day for 4 weeks. 3. Atorvastatin decreased plasma total and LDL-cholesterol by 29% (P < 0.0001) and 41% (P < 0.001), respectively, and increased LDLR mRNA abundance, in absolute terms, by 35% (P < 0.001) and 31% (P < 0.0001) and 37% (P = 0.01) relative to reference GAPDH and beta-actin mRNA, respectively. In contrast, atorvastatin had no significant effect on LRP or HMGCR mRNA levels. 4. The increase in LDLR mRNA in circulating mononuclear cells agrees with the few human studies conducted, as well as with in vitro and animal studies, whereas the unchanged HMGCR mRNA is consistent with the hepatic specificity of atorvastatin. The present study firmly documents an increase in LDLR mRNA levels in response to statin administration in normal humans.

Functional alterations of myeloid cell subsets in hyperlipidaemia: relevance for atherosclerosis

Atherosclerosis is a chronic inflammatory disease wherein the infiltration of myeloid cells of the vessel wall is a hallmark event. Lymphocytes, platelets and endothelial cells stand out as prominent suspects being involved in atherosclerosis. However, recent advances suggest a crucial role for myeloid leucocytes, specifically monocyte subsets, neutrophils, dendritic cells and endothelial progenitor cells. These cell types are not just rapidly recruited or already reside in the vascular wall, but also initiate and perpetuate core mechanisms in plaque formation and destabilization. Hyperlipidaemia is an independent risk factor for atherosclerosis. Herein, hyperlipidaemia skews myeloid cell haemostasis, phenotype and transcriptional regulation of pro-inflammatory factors ultimately promoting myeloid cell extravasation and atherosclerosis. We here review the role of myeloid cells in atherosclerosis as well as the effects of hyperlipidaemia on these cells.

Atorvastatin modifies the protein profile of circulating human monocytes after an acute coronary syndrome

Aggressive treatment with high-dose atorvastatin reduces more effectively the incidence of cardiovascular events than moderate statin therapy. The mechanism of this benefit has not been fully elucidated. In order to know the potential effects of statin treatment on the protein expression of circulating monocytes in acute coronary syndrome (ACS) patients, a proteomic analysis of these cells was carried out by 2-DE and MS. Twenty-five patients with non-ST-elevation acute coronary syndrome (NSTEACS) were randomized, the fourth day after admission, to receive ATV 80 mg/dL (n = 14) or conventional treatment (CT) (n = 11), for two months. Blood was withdrawn at the end of the treatment, and monocytes were extracted for proteomic analysis and their protein expression patterns determined. Age, sex, total cholesterol, LDL, HDL, triglycerides, body mass index, presence of hypertension, diabetes, and smoking status were not significantly different between the two groups of patients. The expression of 20 proteins was modified by intensive ATV. Among the most relevant results stand out the normalization by intensive ATV treatment of the expression of proteins that modulate inflammation and thrombosis such as protein disulfide isomerase ER60 (PDI), Annexin I, and prohibitin, or that have other protective effects as HSP-70. Thus, this approach shed light at the molecular level of the beneficial mechanisms of anti-atherothrombotic drugs.

CD36: a multi-modal target for acute stroke therapy

A role for CD36 in the pathogenesis of atherosclerosis, inflammation and lipid metabolism has been well-documented. However, little is known about the role of CD36 in cerebral ischemia. The intent of this review is to develop the concept that CD36, whose functions have been implicated in other pathological events, is a prototypic inflammatory receptor that contributes to the pathogenesis of cerebral ischemia. The importance of CD36 as a treatment target is indicated by the fact that many treatment strategies that are effective in experimental models of stroke exhibit little or no efficacy in clinical trials. The failure of clinical trials may be due to the use of animal models of stroke that do not reflect traditional risk factors for stroke in humans. The discussion will be focused on two risk factors, hyperlipidemia and diabetes, that modulate CD36 responses. Blocking the expression and function of CD36 by pharmacological or genetic means will provide insight not only toward identifying CD36 as a novel molecular target but also for developing effective therapeutic strategies to treat stroke victims. More importantly, coupling clinically relevant conditions with CD36-mediated ischemic injury may provide an appropriate animal model paradigm and develop a scientific understanding that could lead to clinical translational studies involving human subjects.

Differentiation of bone marrow-derived endothelial progenitor cells is shifted into a proinflammatory phenotype by hyperglycemia

Bone marrow (BM)-derived endothelial progenitor cells (EPC) contribute to vascular maintenance by participating in angiogenesis, re-endothelialization, and remodeling. Myeloid progenitor cells in the BM are functionally and quantitatively an important precursor pool for cells that contribute to these processes. However, these precursor pools in the BM also give rise to important effector cells of the innate immune system, such as macrophages and dendritic cells. We hypothesized that the disturbed repair responses that are being observed in diabetes mellitus are also related to an effect on functional and differentiation characteristics at the level of this bone marrow precursor pool. Indeed, we observed that bone marrow differentiation cultures for EPC, macrophages (Mph), or dendritic cells (DC) from hyperglycemic BM yielded 40% fewer EPC and 50% more Mph compared with control BM. These changes were directly related to the hemoglobin A(1C) levels of the donor mice. BM-derived DC numbers were not affected by hyperglycemia. The composition of the BM was not altered; in particular, the numbers of CD31+/Ly6C+ cells, which serve as common progenitors for EPC, Mph, and DC, were unaffected. In addition, BM-derived EPC from hyperglycemic mice were less angiogenic and more proinflammatory in regards to endocytosis, T-cell activation, and interleukin 12 production. HMG-CoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase inhibition by statin supplementation of the culture medium counteracted these hyperglycemia-induced changes. Our study results show that hyperglycemia alters the differentiation fate of BM precursor cells, reducing the potential to generate vascular regenerative cells and favoring the development of proinflammatory cells.

The role of oxidative stress and antioxidant defenses in Buerger disease and atherosclerotic peripheral arterial occlusive disease

The aim of this study was to determine the status and the role of oxidative stress and antioxidant defenses in patients with Buerger disease and atherosclerotic peripheral arterial occlusive disease (PAOD). Seventy-three subjects resembling each other in general characteristics were involved in the study: 21 with lower extremity PAOD (mean age 53.05 +/- 10.8 years, 17 men and four women), 22 with Buerger disease (mean age 38.59 +/- 6.4 years, 19 men and three women), and 30 healthy volunteers (mean age 38.59 +/- 6.4 years, 22 men and eight women). We measured the levels of plasma malondialdehyde (MDA), paraoxonase (PON1), protein carbonyls, arylesterase, nitric oxide (NO), serum oxidized low-density lipoprotein (ox-LDL) and MDA, glutathione (GSH), glutathione reductase (GSH-red), glutathione peroxidase (GSH-px), superoxide dismutase (SOD), and catalase (CAT) in erythrocytes. Plasma protein carbonyls, serum ox-LDL, and plasma and erythrocyte MDA were significantly high in the Buerger disease group compared to the PAOD and control groups (p < 0.001). Plasma PON1 levels and GSH and GSH-px levels in erythrocytes in the Buerger disease group were significantly low compared to the PAOD and control groups (p < 0.001). GSH-red, SOD, and CAT levels in erythrocytes in the Buerger disease group were significantly lowcompared to the PAOD group (p < 0.01, p < 0.001, and p < 0.001, respectively). NO levels were significantly lower in the PAOD group compared to the control group (p < 0.05). The balance between oxidative stress and antioxidant capacity is more seriously impaired in Buerger disease than PAOD.

Atorvastatin decreases stearoyl-CoA desaturase gene expression in THP-1 macrophages incubated with oxidized LDL

Statins, inhibitors of HMG-CoA reductase, reduce plasma low-density lipoprotein (LDL) cholesterol levels decreasing the incidence of coronary events. However, the observed benefit of statins appears to extend beyond their lipid-lowering effects. Previous studies by our group have demonstrated that atorvastatin in oxidized LDL incubated macrophages modifies the gene expression profile of certain enzymes involved in fatty acid metabolism, mainly stearoyl-CoA desaturase (SCD). SCD is a rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids and its expression is mediated by sterol regulatory element-binding protein-1 (SREBP-1). The aim of this study was to determine whether atorvastatin might affect the fatty acid composition in macrophages and if their SCD gene expression profile could explain this effect. Therefore, THP-1 macrophages were treated with atorvastatin and native or oxidized LDL, their fatty acid composition was determined by gas-chromatography, and the SCD and SREBP-1 gene expression profile was analysed using quantitative RT-PCR. We found that atorvastatin reduces the percentage of palmitoleic and oleic acids in THP-1 cells incubated with oxLDL, which could be explained by the inhibition of SCD and SREBP-1 gene expression. The observed results were reversed when mevalonate was added to THP-1 macrophages. This would suggest that inhibition of SCD in THP-1 macrophages incubated with oxLDL and the change in fatty acid composition is an important effect of atorvastatin.