Rationale and design of the CV-PREVITAL study: an Italian multiple cohort randomised controlled trial investigating innovative digital strategies in primary cardiovascular prevention

INTRODUCTION

Prevention of cardiovascular disease (CVD) is of key importance in reducing morbidity, disability and mortality worldwide. Observational studies suggest that digital health interventions can be an effective strategy to reduce cardiovascular (CV) risk. However, evidence from large randomised clinical trials is lacking.

METHODS AND ANALYSIS

The CV-PREVITAL study is a multicentre, prospective, randomised, controlled, open-label interventional trial designed to compare the effectiveness of an educational and motivational mobile health (mHealth) intervention versus usual care in reducing CV risk. The intervention aims at improving diet, physical activity, sleep quality, psycho-behavioural aspects, as well as promoting smoking cessation and adherence to pharmacological treatment for CV risk factors. The trial aims to enrol approximately 80 000 subjects without overt CVDs referring to general practitioners' offices, community pharmacies or clinics of Scientific Institute for Research, Hospitalization and Health Care (Italian acronym IRCCS) affiliated with the Italian Cardiology Network. All participants are evaluated at baseline and after 12 months to assess the effectiveness of the intervention on short-term endpoints, namely improvement in CV risk score and reduction of major CV risk factors. Beyond the funded life of the study, a long-term (7 years) follow-up is also planned to assess the effectiveness of the intervention on the incidence of major adverse CV events. A series of ancillary studies designed to evaluate the effect of the mHealth intervention on additional risk biomarkers are also performed.

ETHICS AND DISSEMINATION

This study received ethics approval from the ethics committee of the coordinating centre (Monzino Cardiology Center; R1256/20-CCM 1319) and from all other relevant IRBs and ethics committees. Findings are disseminated through scientific meetings and peer-reviewed journals and via social media. Partners are informed about the study's course and findings through regular meetings.

TRIAL REGISTRATION NUMBER

NCT05339841.

Prenylcysteine oxidase 1, an emerging player in atherosclerosis

The research into the pathophysiology of atherosclerosis has considerably increased our understanding of the disease complexity, but still many questions remain unanswered, both mechanistically and pharmacologically. Here, we provided evidence that the pro-oxidant enzyme Prenylcysteine Oxidase 1 (PCYOX1), in the human atherosclerotic lesions, is both synthesized locally and transported within the subintimal space by proatherogenic lipoproteins accumulating in the arterial wall during atherogenesis. Further, Pcyox1 deficiency in Apoe^-/- mice retards atheroprogression, is associated with decreased features of lesion vulnerability and lower levels of lipid peroxidation, reduces plasma lipid levels and inflammation. PCYOX1 silencing in vitro affects the cellular proteome by influencing multiple functions related to inflammation, oxidative stress, and platelet adhesion. Collectively, these findings identify the pro-oxidant enzyme PCYOX1 as an emerging player in atherogenesis and, therefore, understanding the biology and mechanisms of all functions of this unique enzyme is likely to provide additional therapeutic opportunities in addressing atherosclerosis.

Dkk (Dickkopf) Proteins

Clinical and preclinical studies over the past 3 decades have uncovered a multitude of signaling pathways involved in the initiation and progression of atherosclerosis. From these studies, signaling by proteins of the Wnt family has recently emerged as an important player in the development of atherosclerosis. Wnt signaling is characterized by a large number of ligands, receptors, and coreceptors and can be regulated at many different levels. Among Wnt modulators, the evolutionary conserved Dkk (Dickkopf) proteins, and especially Dkk-1, the founding member of the family, are the best characterized. The role of Dkks in the pathophysiology of the arterial wall is only partially understood, but their involvement in atherosclerosis is becoming increasingly evident. This review introduces recent key findings on Dkk proteins and their functions in atherosclerosis and discusses the potential importance of modulating Dkk signaling as part of a novel, improved strategy for preventing and treating atherosclerosis-related diseases.

Visual Overview—

An online visual overview is available for this article.

Identification of DKK-1 as a novel mediator of statin effects in human endothelial cells

This study shows that DKK-1, a member of the Dickkopf family and a regulator of the Wnt pathways, represents a novel target of statins which, through the inhibition of HMG-CoA reductase and of non-steroidal isoprenoid intermediates, exert extra-beneficial effect in preventing atherosclerosis beyond their effect on the lipid profile. We found that atorvastatin downregulates DKK-1 protein (−88.3 ± 4.1%) and mRNA expression (−90 ± 4.2%) through the inhibition of Cdc42, Rho and Rac geranylgeranylated proteins. Further, a combined approach based on the integration of label-free quantitative mass spectrometry based-proteomics and gene silencing allowed us to demonstrate that DKK-1 itself mediates, at least in part, statin effects on human endothelial cells. Indeed, DKK-1 is responsible for the regulation of the 21% of the statin-modulated proteins, which include, among others, clusterin/apoJ, plasminogen activator inhibitor type 1 (PAI-1), myristoylated alanine-rich C-kinase substrate (MARCKS), and pentraxin 3 (PTX3). The Gene Ontology enrichment annotation revealed that DKK-1 is also a potential mediator of the extracellular matrix organization, platelet activation and response to wounding processes induced by statin. Finally, we found that plasma level of DKK-1 from cholesterol-fed rabbits treated with atorvastatin (2.5 mg/kg/day for 8 weeks) was lower (−42 ± 23%) than that of control animals. Thus, DKK-1 is not only a target of statin but it directly regulates the expression of molecules involved in a plethora of biological functions, thus expanding its role, which has been so far restricted mainly to cancer.

Reprint of: Proteomics in cardiovascular diseases: Unveiling sex and gender differences in the era of precision medicine

Cardiovascular diseases (CVDs) represent the most important cause of mortality in women and in men. Contrary to the long-standing notion that the effects of the major risk factors on CVD outcomes are the same in both sexes, recent evidence recognizes new, potentially independent, sex/gender-related risk factors for CVDs, and sex/gender-differences in the clinical presentation of CVDs have been demonstrated. Furthermore, some therapeutic options may not be equally effective and safe in men and women. In this context, proteomics offers an extremely useful and versatile analytical platform for biomedical researches that expand from the screening of early diagnostic and prognostic biomarkers to the investigation of the molecular mechanisms underlying CDVs. In this review, we summarized the current applications of proteomics in the cardiovascular field, with emphasis on sex and gender-related differences in CVDs.

SIGNIFICANCE

Increasing evidence supports the profound effect of sex and gender on cardiovascular physio-pathology and the response to drugs. A clear understanding of the mechanisms underlying sexual dimorphisms in CVDs would not only improve our knowledge of the etiology of these diseases, but could also inform health policy makers and guideline committees in tailoring specific interventions for the prevention, treatment and management of CVDs in both men and women.

Cholesterol-induced Thrombogenicity of the Vessel Wall: Inhibitory Effect of Fluvastatin

High cholesterol levels are a known risk factor for coronary events. The molecular links between high serum cholesterol and the increased thrombogenicity of the arterial wall are still matter of investigation. In the present study we investigate the relationship between plasma cholesterol, thrombus formation and TF expression in a atherosclerotic rabbit model.

Hypercholesterolemic rabbits showed a pronounced TF staining as well as NF-κB activation in the aortic arch. A consistent vessel wall platelet deposition was also observed. Treatment with fluvastatin reduced lipid accumulation, TF overexpression (-60%), NF-κB activation, and platelet deposition (-56%). In vitro studies showed that the drug upregulated IκBa in unstimulated as well as in TNFa-stimulated cells and also impaired the TNF-α-induced Cdc42 prenylation, indicating that fluvastatin interferes with the transcriptional activation of TF gene.

These results indicate that the prothrombotic phenotype of arterial wall, associated with elevated serum cholesterol levels, is mediated by TF overexpression. Fluvastatin treatment reduces the prothrombotic tendency by inhibiting TF synthesis.

Proteomics in cardiovascular diseases: Unveiling sex and gender differences in the era of precision medicine

Cardiovascular diseases (CVDs) represent the most important cause of mortality in women and in men. Contrary to the long-standing notion that the effects of the major risk factors on CVD outcomes are the same in both sexes, recent evidence recognizes new, potentially independent, sex/gender-related risk factors for CVDs, and sex/gender-differences in the clinical presentation of CVDs have been demonstrated. Furthermore, some therapeutic options may not be equally effective and safe in men and women. In this context, proteomics offers an extremely useful and versatile analytical platform for biomedical researches that expand from the screening of early diagnostic and prognostic biomarkers to the investigation of the molecular mechanisms underlying CDVs. In this review, we summarized the current applications of proteomics in the cardiovascular field, with emphasis on sex and gender-related differences in CVDs.

SIGNIFICANCE

Increasing evidence supports the profound effect of sex and gender on cardiovascular physio-pathology and the response to drugs. A clear understanding of the mechanisms underlying sexual dimorphisms in CVDs would not only improve our knowledge of the etiology of these diseases, but could also inform health policy makers and guideline committees in tailoring specific interventions for the prevention, treatment and management of CVDs in both men and women.

Normal human mitral valve proteome: A preliminary investigation by gel-based and gel-free proteomic approaches

The mitral valve is a highly complex structure which regulates blood flow from the left atrium to the left ventricle (LV) avoiding a significant forward gradient during diastole or regurgitation during systole. The integrity of the mitral valve is also essential for the maintenance of normal LV size, geometry, and function. Significant advances in the comprehension of the biological, functional, and mechanical behavior of the mitral valve have recently been made. However, current knowledge of protein components in the normal human mitral valve is still limited and complicated by the low cellularity of this tissue and the presence of high abundant proteins from the extracellular matrix. We employed here an integrated proteomic approach to analyse the protein composition of the normal human mitral valve and reported confident identification of 422 proteins, some of which have not been previously described in this tissue. In particular, we described the ability of pre-MS separation technique based on liquid-phase IEF and SDS-PAGE to identify the largest number of proteins. We also demonstrated that some of these proteins, e.g. αB-Crystallin, septin-11, four-and-a-half LIM domains protein 1, and dermatopontin, are synthesised by interstitial cells isolated from human mitral valves. These initial results provide a valuable basis for future studies aimed at analysing in depth the mitral valve protein composition and at investigating potential pathogenetic molecular mechanisms. Data are available via ProteomeXchange with identifier PXD004397.

Fibronectin extra domain A stabilises atherosclerotic plaques in apolipoprotein E and in LDL-receptor-deficient mice

The primary transcript of fibronectin undergoes alternative splicing in the cassette-type EDA and EDB exons and in the IIICs segment to generate different protein isoforms. Human carotid atherosclerotic plaques with a more stable phenotype are enriched with EDA containing fibronectin (FN-EDA). The aim of this study was to investigate the role of EDA containing fibronectin during atherogenesis. Mice constitutively expressing or lacking the EDA domain of fibronectin (EDA+/+ or EDA-/-)were crossed with ApoE-/- or LDL-R-/- mice and fed with a western type diet for 12 weeks. Lack of FN-EDA resulted in reduced atherosclerosis and in a plaque phenotype characterised by decreased calponin positive VSMC's (-15 %) and increased macrophages (+20 %). This was paralleled by increased MMP2, MMP9, and reduced TIMP2, collagen 1A1, 1A2 and 3A1 gene expression compared to that of wild-type and EDA+/+ mice. In vitro, VSMCs and macrophages isolated from EDA-/- miceshowed increased MMPs expression and activity compared to wild-type or EDA+/+ mice. Albumin-Cre recombinase/EDA+/+/ApoE-/- mice, which produceEDA containing FN only in peripheral tissues, presented an extension, a composition and a gene expression pattern in the atherosclerotic lesions similar to that of controls. The inclusion of EDA in FN results in larger atherosclerotic plaques compared to mice lacking EDA but with a more favourable phenotype in two animals models of atherosclerosis. This effect depends on the EDA-containing fibronectin produced by cells in the vasculature but not in the liver. These observations set the stage for investigating the properties of circulating EDA containing FN in improving plaque stability.

Atorvastatin reduces long pentraxin 3 expression in vascular cells by inhibiting protein geranylgeranylation

BACKGROUND

The long pentraxin PTX3 is an acute-phase multi-functional protein that might play both positive and detrimental effects under different pathophysiological conditions. We previously showed that statins down-regulate the release of PTX3 in human endothelial cells (ECs). The present study investigated the mechanism mediating this effect, its occurrence in other cells involved in atherogenesis, and whether it takes place in experimental atherosclerosis.

METHODS AND RESULTS

We found that atorvastatin (1-5 μmol/L) decreased the production and release of PTX3 in human ECs through a post-transcriptional effect. Co-incubation with mevalonate or geranylgeranyl pyrophosphate prevented this effect. Direct blockade of geranylgeranyl transferase I by GGTI-286, treatment with the Rac inhibitor NSC23766 or silencing of the geranylgeranylated GTPase Rac2 by siRNA closely mimicked the action of atorvastatin. In contrast, inactivation of other geranylgeranylated proteins such as RhoA, RhoB, and RhoC or Rac1 did not affect PTX3 release. In addition, we found that atorvastatin also decreased PTX3 secretion in aortic SMCs through a mechanism likely dependent on protein geranylgeranylation, while no effect was observed in monocytes. Finally, we found that atherosclerotic lesions from cholesterol-fed rabbits treated with atorvastatin (2.5 mg/kg/day for 8 weeks) showed less immunoreactive PTX3 than lesions from control animals.

CONCLUSIONS

Results suggest that statins may interfere with PTX3 expression in vascular cells via inhibition of protein geranylgeranylation. Since PTX3 is increasingly regarded as an important mediator of the inflammatory response underlying atherosclerosis and its complications, these results highlight the need for further studies of the role of PTX3 and its potential pharmacological modulation in cardiovascular disease.

Pharmacology of dipeptidyl peptidase-4 inhibitors: similarities and differences

The dipeptidyl peptidase (DPP)-4 inhibitors, which enhance glucose-dependent insulin secretion from pancreatic β cells by preventing DPP-4-mediated degradation of endogenously released incretin hormones, represent a new therapeutic approach to the management of type 2 diabetes mellitus. The 'first-in-class' DPP-4 inhibitor, sitagliptin, was approved in 2006; it was followed by vildagliptin (available in the EU and many other countries since 2007, although approval in the US is still pending), saxagliptin (in 2009), alogliptin (in 2010, presently only in Japan) and linagliptin, which was approved in the US in May 2011 and is undergoing regulatory review in Japan and the EU. As the number of DPP-4 inhibitors on the market increases, potential differences among the different members of the class become important when deciding which agent is best suited for an individual patient. The aim of this review is to provide a comprehensive and updated comparison of the pharmacodynamic and pharmacokinetic properties of DPP-4 inhibitors, and to pinpoint pharmacological differences of potential interest for their use in therapy. Despite their common mechanism of action, these agents show significant structural heterogeneity that could translate into different pharmacological properties. At the pharmacokinetic level, DPP-4 inhibitors have important differences, including half-life, systemic exposure, bioavailability, protein binding, metabolism, presence of active metabolites and excretion routes. These differences could be relevant, especially in patients with renal or hepatic impairment, and when considering combination therapy. At the pharmacodynamic level, the data available so far indicate a similar glucose-lowering efficacy of DPP-4 inhibitors, either as monotherapy or in combination with other hypoglycaemic drugs, a similar weight-neutral effect, and a comparable safety and tolerability profile. Data on nonglycaemic parameters are scant at present and do not allow a comparison among DPP-4 inhibitors. Several phase III trials of DPP-4 inhibitors are currently ongoing; these trials, along with post-marketing surveillance data, will hopefully increase our knowledge about the long-term efficacy and safety of DPP-4 inhibitor therapy, the effect on pancreatic cell function and peripheral glucose metabolism, and the effect on cardiovascular outcomes in patients with type 2 diabetes.

Role of polymorphonuclear neutrophils in atherosclerosis: current state and future perspectives

Contrary to the long-standing and widely accepted belief that polymorphonuclear neutrophils (PMN) are of marginal relevance in atherosclerosis, evidence revealing a previously unappreciated role of PMN in the process of atherosclerosis is being accumulating. Systemic inflammation involving activated PMN is clearly associated with unstable conditions of coronary artery disease and an increased number of circulating neutrophils is a well-known risk indicator of future cardiovascular outcomes. Furthermore, PMN are activated in a number of clinical conditions associated with high risk of developing atherosclerosis and are detectable into culprit lesions of patients with coronary artery disease. At present, pharmacological interventions aimed at blocking neutrophil emigration from the blood into the arterial wall and/or inhibiting neutrophil-mediated inflammatory functions are not an option for treating atherosclerosis. Nevertheless, several lines of evidence suggest that part of the atheroprotective effects of statins as well as HDL and HDL apolipoproteins may be related to their ability to modulate neutrophilic inflammation in the arterial wall. These hypotheses are not definitely established and warrant for further study. This Review describes the evidence suggesting that PMN may have a causative role in atherogenesis and atheroprogression and discusses the potential importance of modulating neutrophilic inflammation as part of a novel, improved strategy for preventing and treating atherosclerosis.

Raloxifene inhibits matrix metalloproteinases expression and activity in macrophages and smooth muscle cells

Secretion of matrix metalloproteinases (MMPs) by macrophages and smooth muscle cells (SMC) may impair atherosclerotic cap integrity leading to atherosclerosis complications. Selective estrogen receptor modulators (SERMs) have favourable impact on plasma lipid levels, but their role in the prevention of atherosclerosis still remains unclear. We investigated the effects of raloxifene, a second generation SERM, on MMP expression and activity in cultured macrophages and SMC, and in rabbit carotid lesions. Human monocyte-derived macrophages were isolated from blood of healthy donors. SMC were isolated from the intima-media layers of collared rabbit carotid arteries. Cells were incubated for 24h with increasing concentrations of raloxifene. Ovariectomized rabbits fed a 1% cholesterol-rich diet were subjected to pericarotid collar placement and treated with or without 10mgkg(-1)d(-1) raloxifene for 2 weeks. In macrophages, raloxifene treatment (0.1-10microM) significantly reduced MMP-9 gelatinolytic potential in a concentration-dependent manner, without affecting MMP-9 activation. This effect was estrogen receptor (ER)-dependent and due to the inhibition of MMP-9 promoter-driven transcription following an interaction with NF-kB pathway. Similarly, in cultured SMC, raloxifene inhibited up to 40% MMP-2 gelatinolytic activity. In vivo, raloxifene decreased the expression of MMP-2, MMP-3, and MMP-9 by intimal cells and the total gelatinolytic activity of collared carotids. These effects were accompanied by reduction of lesion size and inhibition of macrophage accumulation. Overall, results indicate that raloxifene may reduce MMPs expression and activity in macrophages and smooth muscle cells and favourably affect lesion formation.

Perivascular carotid collar placement induces neointima formation and outward arterial remodeling in mice independent of apolipoprotein E deficiency or Western-type diet feeding

We investigated the influence of apolipoprotein E deficiency and Western-type diet feeding on the development and composition of neointimal lesions induced by periadventitial carotid placement of a non-occlusive collar in mice. ApoE-/- and wild-type mice were fed a Western-type diet or chow diet for 4 weeks before collar surgery. Diets were continued after collar placement for 6 or 12 weeks. Compared to sham-operated arteries, collared carotids showed significant neointima formation, lumen loss, and outward remodeling in both apoE-/- and wild-type mice. These changes were not affected by either the genotype or the diet. Conversely, significant differences in neointima composition were detected between the two genotypes, with apoE-/- mice showing greater lipid deposition and lower SMC accumulation compared to wild-type mice, independent of the dietetic regimen. Altogether, the results of the present study indicate that although lesion composition may be influenced by genotype, neointima formation and arterial remodeling in the murine perivascular carotid collar model occur independent of the exposure to atherogenic diet or the presence of a sensitized genotype such as apoE-/-. The murine perivascular carotid collar model would thus be suitable for investigating neointima formation, arterial remodeling, and their potential pharmacological modulation in the setting of different genetic and dietary conditions.

Raloxifene elicits combined rapid vasorelaxation and long-term anti-inflammatory actions in rat aorta

Previous studies reported the ability of raloxifene to acutely relax arterial and venous vessels, but the underlying mechanisms are controversial. Anti-inflammatory effects of the drug have been reported in nonvascular tissues. Therefore, the aim of this study was to investigate the nature of short- and long-term effects of raloxifene on selected aspects of vascular function in rat aorta. Isometric tension changes in response to raloxifene were recorded in aortic rings from ovariectomized female rats that underwent estrogen replacement, whereas long-term experiments were performed in isolated aortic smooth muscle cells (SMCs). Raloxifene (0.1 pM-0.1 microM) induced acute vasorelaxation through endothelium- and nitric oxide (NO)-dependent, prostanoid-independent mechanisms. The relaxant response to raloxifene was significantly weaker than that to 17beta-estradiol and was sensitive to neither the nonselective estrogen receptor antagonist ICI 182,780 [7,17-[9[(4,4,5,5,5-pentafluoropentyl)sulfinyl]nonyl]estra-1,3,5(10)-triene-3,17-diol] nor a selective estrogen receptor (ER) alpha antagonist. This rapid vasorelaxant effect was retained in aortic rings from rats treated with 0.1 mg/kg, but not 1 mg/kg, lipopolysaccharide, 4 h before sacrifice. In cultured aortic SMCs, raloxifene treatment (1 nM-1 microM) for 24 h reduced inducible NO synthase activation in response to cytokines. This effect was prevented by the selective ERalpha antagonist and was associated with up-regulation of ERalpha protein levels, which dropped markedly upon cytokine stimulation. These findings illustrate the relevance of classic ER-dependent pathways to the vascular anti-inflammatory effects rather than to the nongenomic vasorelaxation induced by raloxifene and may assist in the design of novel ER isoform-selective estrogen-receptor modulators targeted to the vascular system.

Statins effect on smooth muscle cell proliferation

Clinical trials have firmly established that 3-hydroxy-3-methylglutaryl-coenzyme-A reductase inhibitors (statins) can induce regression of vascular atherosclerosis as well as reduction of cardiovascular-related morbidity and death in patients with and without coronary artery disease. These beneficial effects of statins are usually assumed to result from their ability to reduce cholesterol synthesis. However, because mevalonic acid is the precursor not only of cholesterol but also of many nonsteroidal isoprenoid compounds, inhibition of 3-hydroxy-3-methylglutaryl-coenzyme-A reductase may result in pleiotropic effects. Indeed, statins can interfere with major events involved in the formation and the evolution of atherosclerotic lesions, such as arterial myocyte migration and proliferation and cholesterol accumulation, independent of their hypolipidemic properties. The aim of this article is to focus on clinical and experimental data that show that statins possess effects beyond cholesterol lowering, particularly on arterial smooth muscle cell proliferation. The contribution of these direct vascular effects to the reduction of cardiovascular events observed in clinical trials with statins represents one of the major challenges for future studies to understand the antiatherosclerotic benefits of these agents.

Rupture of the atherosclerotic plaque: does a good animal model exist?

By its very nature, rupture of the atherosclerotic plaque is difficult to study directly in humans. A good animal model would help us not only to understand how rupture occurs but also to design and test treatments to prevent it from happening. However, several difficulties surround existing models of plaque rupture, including the need for radical interventions to produce the rupture, lack of direct evidence of rupture per se, and absence of convincing evidence of platelet- and fibrin-rich thrombus at the rupture site. At the present time, attention should therefore focus on the processes of plaque breakdown and thrombus formation in humans, whereas the use of animal models should probably be reserved for studying the function of particular genes and for investigating isolated features of plaques, such as the relationship between cap thickness and plaque stability.

Safety considerations for statins

PURPOSE OF REVIEW

The hydroxymethyl glutaryl coenzyme A reductase inhibitors or statins offer important benefits for the large populations of individuals at high risk for coronary heart disease. These drugs have a good safety profile. Nevertheless, differences in physicochemical and pharmacokinetic properties between statins may translate into significant differences in long-term safety. This review focuses on long-term adverse effects related to statin use, namely hepatotoxicity and myopathy. Moreover, the most common drugs used in combination with statins in long-term therapies are analyzed in terms of possible drug/drug interactions affecting the safety of statins.

RECENT FINDINGS

The withdrawal of cerivastatin from the global market in 2001, because of severe cases of rhabdomyolysis, highlighted concerns regarding the safety of the entire class. Afterwards, the role of statins and their interactions with other drugs in precipitating this condition have been carefully reviewed. In approximately 60% of the total number of cases, statin-related rhabdomyolysis was found to be related to drug/drug interactions. Recently, all cases of fatal rhabdomyolysis associated with statin use have been reported to the US Food and Drug Administration. This has shown that fatal rhabdomyolysis among statin users is a rare event, the reporting rates being much less than one death per million prescriptions in the case of all statins except cerivastatin.

SUMMARY

The safety and tolerability of the available statins support their use as the first-line treatment of patients at high risk for coronary heart disease, since the clinical benefits greatly outweigh the small risk of myopathy. Nevertheless, clinicians should be aware of the adverse effects possibly related to statin therapy, particularly in patients at high risk for coronary heart disease and requiring long-term multiple-drug therapies.

Polymorphonuclear leukocyte-myocyte interaction: an early event in collar-induced rabbit carotid intimal thickening

The importance of mononuclear leukocyte (MO) adhesion to dysfunctional endothelium and migration to the subendothelial space in the early phases of atherogenesis is well established. Few studies have addressed the relevance of polymorphonuclear leukocytes (PMNs) in the context of evolving lesions, and nothing is known about PMN interaction with vascular smooth muscle cells (SMCs). In this study, we investigated leukocyte/SMC interactions in a model of rabbit carotid injury induced by placement of a silastic collar. This procedure leads to the development of intimal thickening characterized by SMC accumulation preceded by an abundant leukocyte infiltration. By transmission electron microscopy and immunocytochemistry, we demonstrated the occurrence of PMN infiltration starting at 6 h and ceasing within 72 h after collar placement. A previously unknown extensive interaction between medial myocytes and PMNs was detected, referring to emperipolesis, an active phenomenon of cells engulfing other cells in a process other than phagocytosis. PMNs, but not MOs, were internalized by SMCs, which showed ultrastructural features intermediate between the true contractile and the fully synthetic phenotype without exhibiting any sign of injury. Emperipolesis preceded any detectable cell proliferation in the vessel wall and disappeared within 72 h, following the kinetic of PMN infiltration in the vessel wall. In summary, our findings show the occurrence of an active and selective interaction between PMNs and SMCs via emperipolesis during the early phases of intimal thickening after perivascular collaring. However, the overall etiology of the phenomena described in the present study and their pathophysiological significance should be further investigated.

Cholesterol-induced thrombogenicity of the vessel wall: inhibitory effect of fluvastatin

High cholesterol levels are a known risk factor for coronary events. The molecular links between high serum cholesterol and the increased thrombogenicity of the arterial wall are still matter of investigation. In the present study we investigate the relationship between plasma cholesterol, thrombus formation and TF expression in a atherosclerotic rabbit model. Hypercholesterolemic rabbits showed a pronounced TF staining as well as NF-kappaB activation in the aortic arch. A consistent vessel wall platelet deposition was also observed. Treatment with fluvastatin reduced lipid accumulation, TF overexpression (-60%), NF-kappaB activation, and platelet deposition (-56%). In vitro studies showed that the drug upregulated IkappaB alpha in unstimulated as well as in TNFalpha-stimulated cells and also impaired the TNFalpha-induced Cdc42 prenylation, indicating that fluvastatin interferes with the transcriptional activation of TF gene. These results indicate that the prothrombotic phenotype of arterial wall, associated with elevated serum cholesterol levels, is mediated by TF overexpression. Fluvastatin treatment reduces the prothrombotic tendency by inhibiting TF synthesis.

Fluvastatin reduces tissue factor expression and macrophage accumulation in carotid lesions of cholesterol-fed rabbits in the absence of lipid lowering

The expression of tissue factor (TF), mainly by infiltrated inflammatory cells, has been shown to be responsible for the thrombogenicity associated with atheroma. The contribution of the nonlipid-related effects of statins to the clinical benefits of statin therapy is currently under intense investigation. In this study, we evaluated the ability of fluvastatin to modulate TF expression and macrophage accumulation in rabbit carotid intimal lesions independently of cholesterol lowering. Male rabbits were fed for 30 days a 1% cholesterol-rich diet with or without fluvastatin at 5 mg/kg per day. Two weeks from the start of treatment, a silastic collar was placed around the carotid artery. Fifteen days later, the animals were killed, and carotid segments were excised and processed. The atherogenic diet caused a consistent increase in plasma cholesterol levels (610+/-231 mg/dL versus 50+/-9 mg/dL at baseline), which were not affected by fluvastatin (603+/-248 mg/dL). In the rabbits fed a high cholesterol diet without fluvastatin, an intimal lesion with macrophage accumulation and TF expression was detected. Fluvastatin significantly reduced TF and macrophage content of the lesion (-50% for both). Results indicate that fluvastatin may attenuate the inflammatory and thrombogenic potential of atherosclerotic lesions through a mechanism(s) other than cholesterol reduction, providing new insight regarding the complex mode of action of statins.

Clinically relevant pleiotropic effects of statins: drug properties or effects of profound cholesterol reduction?

Clinical trials have firmly established that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) can induce the regression of vascular atherosclerosis and reduce cardiovascular-related morbidity and death in patients with and without coronary artery disease. It is usually assumed that these beneficial effects are due to the ability of statins to reduce cholesterol synthesis. However, because mevalonic acid is not only the precursor of cholesterol but also of many non-steroidal isoprenoid compounds, the inhibition of HMG-CoA reductase may lead to pleiotropic effects. As shown by the data reported in this review, some statins can interfere with major events involved in the formation of atherosclerotic lesions, regardless of their hypolipidemic properties. The relevance of these effects in humans remains to be established (particularly in view of the high statin doses required to produce a direct vascular action), thus their contribution to the reduction in cardiovascular events observed in clinical trials has become one of the major challenges for future studies aimed at clarifying the anti-atherosclerotic benefits of statins.

Marked neointimal lipoprotein lipase increase in distinct models of proclivity to atherosclerosis: a feature independent of endothelial layer integrity

Lipoprotein lipase (LPL) in the arterial wall has been proposed to enhance the retention of apoB-containing lipoproteins, an early event in atherosclerosis. As the neointima is considered the primary site of lipid accumulation in atherogenesis, the arterial expression and location of LPL was investigated in distinct experimental models of neointimal formation in normolipidemic rabbits and rats. Neointima elicited by balloon aortic denudation or raised beneath an anatomically intact endothelial layer by placing a silastic collar around the common carotid artery, both showed a striking LPL immunostaining that mostly co-localized with neointimal smooth muscle cells. Besides, increased LPL protein and mRNA in deendothelialized aortas was demonstrated by Western and Northern blot analysis, respectively, suggesting an enhanced expression of LPL in injured arteries. It was concluded that LPL is increased in neointima developed in either denuded vessels or arteries with a preserved endothelium, a finding which suggests that LPL abundance may be an attribute of the neointima, whatever the stimulus that promotes its formation. On the basis of former evidence concerning the role of LPL in lipid retention, this study provides a possible explanation for the injury-induced vessel susceptibility to atherosclerosis, and the particular proneness of the neointimal layer to lipid accretion.

Upregulation and activation of Stat6 precede vascular smooth muscle cell proliferation in carotid artery injury model

The role of signal transducers and activators of transcription (STAT) proteins in modulating proliferation and differentiation of various cell types in the hematopoietic system and the central nervous system has been well established. In contrast, the pathophysiological role of these proteins in vascular proliferative diseases has remained unproven, despite in vitro observations emphasizing the involvement of the STAT system in mediating vascular smooth muscle cell (VSMC) proliferation. On the basis of our previous observations demonstrating the occurrence of a specific modulation of Stat6 protein during the proliferative, migratory, and differentiation phases of the developing brain, we investigated whether Stat6 protein is present and modulated in arterial tissue challenged by perivascular injury. The time course of expression and localization of Stat6 after arterial injury was analyzed by immunohistochemistry, Western blot analysis, and confocal microscopy. Six hours after injury, the expression of Stat6 was markedly increased. This overexpression preceded the onset of VSMC proliferation and was downregulated starting from 7 days after injury, coincident with the decline of VSMC proliferation. Moreover, early after injury, Stat6 was predominantly localized at the nuclear level, denoting its functional activation. Conversely, Stat6 staining at later time points was largely cytosolic, suggesting silencing effects of this signaling pathway. These data indicate that Stat6 signaling may contribute to the modifications of gene expression underlying VSMC activation in the context of acute vascular proliferative diseases.

New insights into the pharmacodynamic and pharmacokinetic properties of statins

The beneficial effects of statins are assumed to result from their ability to reduce cholesterol biosynthesis. However, because mevalonic acid is the precursor not only of cholesterol, but also of many nonsteroidal isoprenoid compounds, inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase may result in pleiotropic effects. It has been shown that several statins decrease smooth muscle cell migration and proliferation and that sera from fluvastatin-treated patients interfere with its proliferation. Cholesterol accumulation in macrophages can be inhibited by different statins, while both fluvastatin and simvastatin inhibit secretion of metalloproteinases by human monocyte-derived macrophages. The antiatherosclerotic effects of statins may be achieved by modifying hypercholesterolemia and the arterial wall environment as well. Although statins rarely have severe adverse effects, interactions with other drugs deserve attention. Simvastatin, lovastatin, cerivastatin, and atorvastatin are biotransformed in the liver primarily by cytochrome P450-3A4, and are susceptible to drug interactions when co-administered with potential inhibitors of this enzyme. Indeed, pharmacokinetic interactions (e.g., increased bioavailability), myositis, and rhabdomyolysis have been reported following concurrent use of simvastatin or lovastatin and cyclosporine A, mibefradil, or nefazodone. In contrast, fluvastatin (mainly metabolized by cytochrome P450-2C9) and pravastatin (eliminated by other metabolic routes) are less subject to this interaction. Nevertheless, a 5- to 23-fold increase in pravastatin bioavailability has been reported in the presence of cyclosporine A. In summary, statins may have direct effects on the arterial wall, which may contribute to their antiatherosclerotic actions. Furthermore, some statins may have lower adverse drug interaction potential than others, which is an important determinant of safety during long-term therapy.

Effect of lercanidipine and its (R)-enantiomer on atherosclerotic lesions induced in hypercholesterolemic rabbits

The in vivo antiatherogenic activity of the calcium antagonist lercanidipine and its (R)-enantiomer was investigated in two different types of atherosclerotic lesions (hyperplastic and fatty-streak lesions) in rabbits. Lercanidipine (0.3, 1, and 3 mg kg(-1) week(-1)) as well as its (R)-enantiomer at 3 mg kg(-1) week(-1) were given by subcutaneous injection for 10 weeks to White New Zealand rabbits, with cholesterol feeding beginning at week 2. The hyperplastic lesion was obtained by positioning a hollow silastic collar around one carotid artery, while aortic fatty streak lesions were induced by cholesterol feeding. In untreated animals (n=5), 14 days after collar positioning an intimal hyperplasia was clearly detectable: the arteries without collar showed a intima/media (I/M) ratio of 0.03+/-0.02, whereas in carotids with a collar the ratio was 2+/-0.42. In lercanidipine-treated animals a significant and dose-dependent effect on intimal hyperplasia was observed. I/M ratios were 0.73+/-0.4, 0.42+/-0.1, 0.32+/-0.1 for 0.3, 1, and 3 mg kg(-1) week(-1), respectively (P<0.05). The lercanidipine enantiomer (3 mg kg(-1) week(-1)) was as effective as the racemate (0.41+/-0.11). Proliferation of smooth muscle cells, assessed by incorporation of BrdU into DNA, was reduced by about 50%, 70%, 85%, and 80% by lercanidipine (0.3, 1, and 3 mg kg(-1) week(-1)) and its (R)-enantiomer, respectively. The area of fatty-streaks in the aorta (n = 11-15) was significantly reduced by lercanidipine (3 mg kg(-1) week(-1), 16% vs 27%, P<0.05), a trend was observed also with lower doses. When different segments of the aorta were considered (arch, thoracic, abdominal) a significant and dose-dependent effect in the thoracic and abdominal aorta was observed also at lower doses. The (R)-enantiomer was as effective as lercanidipine. These results suggest a direct antiatherosclerotic effect of lercanidipine, independent of modulation of risk factors such as hypercholesterolemia and/or hypertension as demonstrated by the absence of stereoselectivity.

Gene transfer into the carotid artery using an adventitial collar: comparison of the effectiveness of the plasmid-liposome complexes, retroviruses, pseudotyped retroviruses, and adenoviruses

We studied the efficiency of plasmid/liposome complexes, Moloney murine leukemia virus-derived (MMLV) retroviruses, pseudotyped vesicular stomatitis virus protein-G (VSV-G)-containing retroviruses, and adenoviruses in delivering genes into the rabbit carotid artery using a silastic collar applied to the adventitia. This method was used for gene transfer because (a) it provides a gene delivery reservoir; (b) no intraluminal manipulations are performed; (c) installation of the collar induces arterial smooth muscle cell (SMC) proliferation and enhances retroviral gene transfer efficiency where target cell proliferation is required. The transfer of the beta-galactosidase (lacZ) marker gene to the adventitia and media occurred with all gene transfer systems. Adenoviruses also transferred the beta-galactosidase gene to some endothelial cells. After 5 days, adenoviral vectors produced the highest gene transfer efficiency with up to 10%+/-6% of cells showing beta-galactosidase activity. Pseudotyped VSV-G retroviruses were also effective in achieving gene transfer in 0.05%+/-0.03% of cells in the adventitia and media. Plasmid/liposome complexes and MMLV retroviruses infected 0.05%+/-0.03% and <0.01%+/-0.01% of cells, respectively. It is concluded that replication-deficient adenoviruses, VSV-G pseudotyped retroviruses, and plasmid/liposome complexes can be used for gene transfer to the arterial wall using the collar method. Because the endothelium remains anatomically present throughout the experiments, the model may be useful for the gene transfer studies involving diffusible or secreted gene products that primarily act on the endothelium. Effects on medial SMC and even endothelium can be achieved from the adventitial side, suggesting an alternative route for the delivery of therapeutically useful genes into the arterial wall.

The menopause and lipid metabolism: strategies for cardiovascular disease prevention

The menopause and its biology are as yet still incompletely understood. Very little is known about biological and molecular changes in cardiovascular target tissues and organs after menopause. Experimental and clinical evidence indicate that prevention of cardiovascular disease by estrogens is aimed both at the correction of risk factors and at the direct control of vessel structure and function. The effects of progestogens on these processes are still debated. Few other medical interventions have as great a potential for affecting morbidity and mortality as does hormone replacement therapy in postmenopausal women. Hormone replacement therapy has produced effects on health risk, some are reduced, some are raised, while some remain uncertain, suggesting that further testing through specific clinical trials are required before confident recommendations can be made about the full range of benefits and risks. Lipid lowering therapy may be an acceptable alternative for postmenopausal women at risk for cardiovascular disease.

Proapoptotic effect of atorvastatin on stimulated rabbit smooth muscle cells

The in vitro and in vivo activity of atorvastatin and other 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase inhibitors (fluvastatin, pravastatin and simvastatin) has been investigated. Atorvastatin, fluvastatin, pravastatin and simvastatin caused a significant and dose-dependent (0.1-50 microM) reduction in cell multiplication of vascular smooth muscle cells (SMC) in cultures associated with the retardation of cycling cells in the G1 and G2/M compartments at 24 h, a phenomenon leading to apoptosis (programmed cell death) in several experimental in vitro models. The effects on the cell cycle resulted in a strong inhibition of cell proliferation at 48 h, followed by apoptosis when incubation was prolonged to 72 h as assessed by nuclei morphology and cytofluorimetric analysis of DNA. The apoptotic effect observed for the statins is completely prevented by the addition of exogenous mevalonate at a 100 microm concentration. in vivo SMC proliferation was stimulated by applying a silastic collar to the outside surface of carotid arteries in normocholesterolemic rabbits in the presence of an anatomically intact endothelium. The positioning of the collar promoted apoptosis in control vessels as assessed by Terminal Deoxynucleotidyl Transferase-dUTP-Biotin Nick-End Labeling (TUNEL) assay. The pre-treatment with 5 mg kg-1 per day of atorvastatin before collar insertion strongly increased the number of TUNEL-positive cells, suggesting a pro-apoptotic effect of HMGCoA reductase inhibitors also in vivo, even though cell DNA rearrangement still needs to be excluded. No apoptotic signal was detectable in sham operated arteries with no collar in either control or atorvastatin-treated rabbits. These data indicate that HMGCoA reductase inhibitors effect on the arterial wall may involve the modulation of both cell proliferation and programmed cell deaths supporting a possible role of statins in the prevention of early lesion and restenosis.

Secretory processing of amyloid precursor protein is inhibited by increase in cellular cholesterol content

Plasma-membrane composition plays a crucial role in most of the cellular functions that depend on membrane processes. In virtually all cell types the proteolytic processing of Alzheimer amyloid precursor protein (APP) to generate soluble APP (sAPP) is believed to occur at the plasma membrane or in its immediate proximity. Alteration of this metabolic pathway has been linked to the pathogenesis of Alzheimer's disease. We analysed the effect of membrane cholesterol enrichment on APP metabolism. Incubation of COS cells with increasing concentrations of non-esterified cholesterol carried by rabbit beta-very low-density lipoprotein caused a dose-dependent inhibition of sAPP release: 70% inhibition with 10 microg/ml non-esterified cholesterol. A less pronounced inhibitory effect was observed on treatment with human low-density lipoprotein. Inhibition of sAPP release was independent of receptor-mediated lipoprotein metabolism since simultaneous treatment with chloroquine did not modify the effect of lipoprotein treatment. In addition, treatment with cholesterol dissolved in either ethanol or methyl-beta-cyclodextrin elicited the same effect. Excess non-esterified cholesterol did not cause cell toxicity. Cell cholesterol mass inversely correlated with sAPP release. Progesterone, which inhibits shuttling of non-esterified cholesterol between the plasma membrane and intracellular pools, had no effect on the inhibition of sAPP release from cholesterol-loaded cells, providing indirect evidence that cholesterol may act at the plasma membrane.

In vivo enhanced antitumor activity of carmustine [N,N'-bis(2-chloroethyl)-N-nitrosourea] by simvastatin

The effects of a combination of simvastatin, a cholesterol-lowering agent, and carmustine (BCNU; N,N'-bis(2-chloroethyl)-N-nitrosourea) on experimental C6 glioma were studied in vitro and in vivo. In vitro simvastatin and BCNU alone inhibited cell proliferation in a dose-dependent fashion. A subliminal concentration of simvastatin (0.1 microM) markedly and synergistically increased the BCNU toxicity to C6 glioma cells. The cytofluorimetric analysis of DNA from simvastatin-treated C6 glioma cells showed, besides the already described arrest in G1, an arrest/retardation in G2-M. Mitotic index from C6 cells incubated with simvastatin (10 microM) decreased by about 90%, indicating a specific C6 arrest/retardation in G2. The drug effects could be completely reversed by simvastatin withdrawal or mevalonate addition to the cultured cells. The combination of simvastatin and BCNU resulted predominantly from the profound retardation of cells in the G2-M compartment of the cell cycle. In vivo simvastatin (administered daily mixed with food) and BCNU (single i.p. injection), when given separately, caused a dose-dependent inhibition of labeling index in C6 glioma homografts (ID50, 61 mg/kg/day and 8.7 mg/kg, respectively). The combination of the lowest doses tested (simvastatin, 25 mg/kg/day and BCNU 0.3 mg/kg) resulted in a significant growth delay (compared to either drug alone) in C6 glioma (P < 0.05). There was no significant increase in toxicity as assessed by myelosuppression (WBC counts and bone marrow labeling index) and body weight. The results provide in vivo support for the combined use of simvastatin, a cholesterol-lowering agent, and BCNU in brain tumor treatment.

PKC activity in rat C6 glioma cells: changes associated with cell cycle and simvastatin treatment

The parallel effects of simvastatin on cell cycle and PKC activity in rat C6 glioma cells were investigated. Simvastatin, 2.5 microM, for 24 h resulted in cell growth arrest in early G1 phase of the cell cycle and in a significant increase of total PKC activity (283 +/- 42 vs 470 +/- 61 pmoles/min/mg protein p = 0.002 for control cells and simvastatin-treated cells, respectively). The effect of simvastatin was fully prevented by mevalonate. A time dependent increase of PKC activity was observed in control exponentially free-growing C6 cells approaching confluency: a highly significant negative correlation (r = -0.91 p < 0.0001) between PKC activity and growth rate was calculated. PKC activity was high in cells arrested in G0 by serum starvation (0.4%). Following addition of complete medium (17.5% serum) the PKC activity progressively decreased and reached a minimum when cells traversed the G2/M phase, as determined by DNA analysis distribution. PKC activity dropped 30% in simvastatin-arrested early G1 cells; 44% in hydroxyurea-arrested cells at the G1/S boundary; and 73% in Colcemid mitosis-blocked cells. The results show that C6 glioma cell PKC activity is maximal in a G0 quiescent state and varies at different points of the cell cycle.