Simvastatin modulates chemokine and chemokine receptor expression by geranylgeranyl isoprenoid pathway in human endothelial cells and macrophages

Mononuclear phagocyte morphological response to chemoattractants is dependent on geranylgeranyl pyrophosphate

Statins are used to treat hypercholesterolemia and function by inhibiting the production of the rate-limiting metabolite mevalonate. As such, statin treatment not only inhibits de novo synthesis of cholesterol but also isoprenoids that are involved in prenylation, the posttranslational lipid modification of proteins. The immunomodulatory effects of statins are broad and often conflicting. Previous work demonstrated that statins increased survival and inhibited myeloid cell trafficking in a murine model of sepsis, but the exact mechanisms underlying this phenomenon were unclear. Herein, we investigated the role of prenylation in chemoattractant responses. We found that simvastatin treatment abolished chemoattractant responses induced by stimulation by C5a and FMLP. The inhibitory effect of simvastatin treatment was unaffected by the addition of either farnesyl pyrophosphate (FPP) or squalene but was reversed by restoring geranylgeranyl pyrophosphate (GGPP). Treatment with prenyltransferase inhibitors showed that the chemoattractant response to both chemoattractants was dependent on geranylgeranylation. Proteomic analysis of C15AlkOPP-prenylated proteins identified several geranylgeranylated proteins involved in chemoattractant responses, including RHOA, RAC1, CDC42, and GNG2. Chemoattractant responses in THP-1 human macrophages were also geranylgeranylation dependent. These studies provide data that help clarify paradoxical findings on the immunomodulatory effects of statins. Furthermore, they establish the role of geranylgeranylation in mediating the morphological response to chemoattractant C5a.NEW & NOTEWORTHY The immunomodulatory effect of prenylation is ill-defined. We investigated the role of prenylation on the chemoattractant response to C5a. Simvastatin treatment inhibits the cytoskeletal remodeling associated with a chemotactic response. We showed that the chemoattractant response to C5a was dependent on geranylgeranylation, and proteomic analysis identified several geranylgeranylated proteins that are involved in C5a receptor signaling and cytoskeletal remodeling. Furthermore, they establish the role of geranylgeranylation in mediating the response to chemoattractant C5a.

Use of Statins in Heart Failure with Preserved Ejection Fraction: Current Evidence and Perspectives

Systemic inflammation and coronary microvascular endothelial dysfunction are essential pathophysiological factors in heart failure (HF) with preserved ejection fraction (HFpEF) that support the use of statins. The pleiotropic properties of statins, such as anti-inflammatory, antihypertrophic, antifibrotic, and antioxidant effects, are generally accepted and may be beneficial in HF, especially in HFpEF. Numerous observational clinical trials have consistently shown a beneficial prognostic effect of statins in patients with HFpEF, while the results of two larger trials in patients with HFrEF have been controversial. Such differences may be related to a more pronounced impact of the pleiotropic properties of statins on the pathophysiology of HFpEF and pro-inflammatory comorbidities (arterial hypertension, diabetes mellitus, obesity, chronic kidney disease) that are more common in HFpEF. This review discusses the potential mechanisms of statin action that may be beneficial for patients with HFpEF, as well as clinical trials that have evaluated the statin effects on left ventricular diastolic function and clinical outcomes in patients with HFpEF.

Prenyltransferase gene expression reveals an essential role of prenylation for the inflammatory response in human gingival fibroblasts

BACKGROUND

Prenyltrasferases (PTases) are a class of enzymes known to be responsible for promoting posttranslational modification at the carboxyl terminus of proteins containing a so-called CaaX-motif. The process is responsible for proper membrane localization and the appropriate function of several intracellular signaling proteins. Current research demonstrating the pathomechanistic importance of prenylation in inflammatory illnesses emphasizes the requirement to ascertain the differential expression of PT genes under inflammatory settings, particularly in periodontal disease.

METHODS

Telomerase-immortalized human gingival fibroblasts (HGF-hTert) were cultured and treated with either inhibitors of prenylation (PTI) lonafarnib, tipifarnib, zoledronic acid, or atorvastatin at concentrations of 10 μM in combination with or without 10 μg Porphyromonas gingivalis lipopolysaccharide (LPS) for 24 h. Prenyltransferase genes FNTB, FNTA, PGGT1B, RABGGTA, RABGGTB, and PTAR1 as well as inflammatory marker genes MMP1 and IL1B were detected using quantitative real-time polymerase chain reaction (RT-qPCR). Immunoblot and protein immunoassay were used to confirm the results on the protein level.

RESULTS

RT-qPCR experiments revealed significant upregulation of IL1B, MMP1, FNTA, and PGGT1B upon LPS treatment. PTase inhibitors caused significant downregulation of the inflammatory cytokine expression. Interestingly, FNTB expression was significantly upregulated in response to any PTase inhibitor in combination with LPS, but not upon LPS treatment only, indicating a vital role of protein farnesyltransferase in the proinflammatory signaling cascade.

CONCLUSIONS

In this study, distinct PTase gene expression patterns in pro-inflammatory signaling were discovered. Moreover, PTase inhibiting drugs ameliorated inflammatory mediator expression by a significant margin, indicating that prenylation is a major pre-requisite for innate immunity in periodontal cells.

Cholesterol metabolism in the regulation of inflammatory responses

The importance of biologically active lipid mediators, such as prostanoids, leukotrienes, and specialized pro-resolving mediators, in the regulation of inflammation is well established. While the relevance of cholesterol in the context of atherosclerosis is also widely accepted, the role of cholesterol and its biosynthetic precursors on inflammatory processes is less comprehensively described. In the present mini-review, we summarize the current understanding of the inflammation-regulatory properties of cholesterol and relevant biosynthetic intermediates taking into account the implications of different subcellular distributions. Finally, we discuss the inflammation-regulatory effect of cholesterol homeostasis in the context of SARS-CoV-2 infections.

Statins for primary cardiovascular disease prevention among people with HIV: emergent directions

PURPOSE OF REVIEW

While people with HIV (PWH) are living longer due to advances in antiretroviral therapy, recent data have demonstrated an increased risk of cardiovascular disease (CVD) among this population. This increased risk is thought to be due to both traditional (for example, smoking, diabetes) and HIV-specific (for example, inflammation, persistent immune activation) risk factors. This review focuses on the potential for statin therapy to mitigate this increased risk.

RECENT FINDINGS

Several randomized clinical trials have demonstrated that statins, a class of lipid-lowering medications, are effective as a primary CVD prevention strategy among people without HIV. Among PWH, statins have been shown to lower cholesterol, exert immunomodulatory effects, stabilize coronary atherosclerotic plaque, and even induce plaque regression.

SUMMARY

Prevention of CVD among the aging population of people with controlled, but chronic, HIV is vital. Data exploring primary prevention in this context are thus far limited. The Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE) is ongoing; this trial will inform the field by investigating the effects of pitavastatin calcium as a primary prevention strategy for major adverse cardiovascular events among PWH on antiretroviral therapy (ART) at low-to-moderate traditional CVD risk.

Differential Effects of Gq Protein-Coupled Uridine Receptor Stimulation on IL-8 Production in 1321N1 Human Astrocytoma Cells

G-protein-coupled receptors (GPCRs) trigger various physiological functions. GPCR-mediated effects largely depend on the receptor-associated G-protein subtypes. However, compelling evidence suggests that single receptor proteins activate multiple G-protein subtypes to induce diverse physiological responses. This study compared responses mediated by three different Gq-binding uridine nucleotide receptors, P2Y₂, P2Y₄, and P2Y₆, by measuring Ca²⁺ signaling and interleukin (IL)-8 production. In 1321N1 human astrocytoma cells stably expressing these receptors, agonist stimulation evoked concentration-dependent intracellular Ca²⁺ elevation to a similar extent. In contrast, agonist-induced IL-8 production was prominent in P2Y₆-expressing cells, but not in P2Y₂- and P2Y₄-expressing cells. In addition to inhibition of Gq signaling, G₁₂ signal blockade attenuated uridine 5'-diphosphate (UDP)-induced IL-8 production, suggesting the involvement of a small G-protein pathway. The Rac inhibitor EHop-16 prevented UDP-induced IL-8 release. The P2Y₆-triggered IL-8 production was also inhibited by extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and protein kinase B (Akt) inhibitors. These results suggest that P2Y₆ receptor-induced IL-8 production requires Gq-mediated Ca²⁺ signaling as well as G₁₂-mediated activation of Rac. The results also suggest the importance of considering the involvement of multiple G proteins in understanding GPCR-mediated functions.

The Immunomodulatory Effects of Statins on Macrophages

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors used worldwide to manage dyslipidaemia and thus limit the development of atherosclerotic disease and its complications. These atheroprotective drugs are now known to exert pleiotropic actions outside of their cholesterol-lowering activity, including altering immune cell function. Macrophages are phagocytic leukocytes that play critical functional roles in the pathogenesis of atherosclerosis and are directly targeted by statins. Early studies documented the anti-inflammatory effects of statins on macrophages, but emerging evidence suggests that these drugs can also enhance pro-inflammatory macrophage responses, creating an unresolved paradox. This review comprehensively examines the in vitro, in vivo, and clinical literature to document the statin-induced changes in macrophage polarization and immunomodulatory functions, explore the underlying mechanisms involved, and offer potential explanations for this paradox. A better understanding of the immunomodulatory actions of statins on macrophages should pave the way for the development of novel therapeutic approaches to manage atherosclerosis and other chronic diseases and conditions characterised by unresolved inflammation.

Molecular targets of statins and their potential side effects: Not all the glitter is gold

Statins are a class of drugs widely used worldwide to manage hypercholesterolemia and the prevention of secondary heart attacks. Currently, available statins vary in terms of their pharmacokinetic and pharmacodynamic profiles. Although the primary target of statins is the inhibition of HMG-CoA reductase (HMGR), the rate-limiting enzyme in cholesterol biosynthesis, statins exhibit many pleiotropic effects downstream of the mevalonate pathway. These pleiotropic effects include the ability to reduce myocardial fibrosis, pathologic cardiac disease states, hypertension, promote bone differentiation, anti-inflammatory, and antitumor effects through multiple mechanisms. Although these pleiotropic effects of statins may be a cause for enthusiasm, there are many adverse effects that, for the most part, are unappreciated and need to be highlighted. These adverse effects include myopathy, new-onset type 2 diabetes, renal and hepatic dysfunction. Although these adverse effects may be relatively uncommon, considering the number of people worldwide who use statins daily, the actual number of people affected becomes quite large. Also, co-administration of statins with several other medications, herbal agents, and foods, which interact through common enzymatic pathways, can have untoward clinical consequences. In this review, we address these concerns.

Simvastatin Improves Myocardial Ischemia Reperfusion Injury through KLF-Regulated Alleviation of Inflammation

Objective. To clarify the protective effect of simvastatin on myocardial ischemia reperfusion injury (MIRI) and the underlying mechanism. Materials and Methods. The MIRI model in rats was firstly constructed. Twenty-four male rats were randomly assigned into the sham group, ischemia-reperfusion (I/R) group, and simvastatin group, with 8 rats in each group. Contents of superoxide dismutase (SOD) and malondialdehyde (MDA), as well as serum levels of CK and inflammatory factors, in rats were determined by the enzyme-linked immunosorbent assay (ELISA). Lactate dehydrogenase (LDH) activity in the three groups was examined. Through flow cytometry and Cell Counting Kit-8 (CCK-8) assay, apoptosis and viability in each group were detected, respectively. Relative levels of HMGB1, Kruppel-like factor 2 (KLF2), eNOS, and thrombomodulin (TM) were finally determined. Results. Simvastatin treatment markedly enhanced SOD activity and reduced contents of MDA, LDH, and creatine kinase (CK) in MIRI rats. The increased apoptosis and decreased viability following MIRI were partially reversed by simvastatin treatment. Besides, MIRI resulted in the upregulation of inflammatory factors and chemokines. Their elevations were abolished by simvastatin. In MIRI rats, simvastatin upregulated KLF2 and p-eNOS. Conclusions. Simvastatin protects inflammatory response at post-MIRI through upregulating KLF2, thus improving cardiac function.

Simvastatin in vitiligo: an update with recent review of the literature

Patients with vitiligo often seek medical attention, as it diminishes their quality of life resulting in significant morbidity. Several topical and systemic therapies are in vogue targeting the immunological aspect of this disease, but results are often unsatisfactory, and complete cure remains elusive. Recently, simvastatin, a 3-hydroxy-3-methylyglutaryl-coenzyme A (HMG-CoA) reductase inhibitor, is being evaluated for vitiligo management because of its multimodal action, easy availability, and low cost. The proposed multimodal actions range from anti-inflammatory, antioxidant, to immunomodulatory properties which may be of therapeutic benefit in vitiligo patients. The authors intend to evaluate the role of simvastatin as a novel therapeutic agent for vitiligo along with relevant review of literature.

Protocol for systematic review and meta-analysis: impact of statins as immune-modulatory agents on inflammatory markers in adults with chronic diseases

INTRODUCTION

Statins, also known as 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, are lipid-lowering agents that are central in preventing or reducing the complications of atherosclerotic cardiovascular disease. Because statins have anti-inflammatory properties, there is considerable interest in their therapeutic potential in other chronic inflammatory conditions. We aim to identify the statin with the greatest ability to reduce systemic inflammation, independent of the underlying disease entity.

METHODS AND ANALYSIS

We aim to conduct a comprehensive search of published and peer-reviewed randomised controlled clinical trials, with at least one intervention arm of a Food & Drug Administration-licensed or European Medicines Agency-licensed statin and a minimum treatment duration of 12 weeks. Our objective is to investigate the effect of statins (atorvastatin, fluvastatin, pitavastatin, pravastatin, rosuvastatin, simvastatin) on lipid profile, particularly, cholesterol low-density lipoprotein and inflammation markers such as high-sensitive C reactive protein (hsCRP), CRP, tumour necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), IL-6, IL-8, soluble cluster of differentiation 14 (sCD14) or sCD16 in adults, published in the last 20 years (between January 1999 and December 2019). We aim to identify the most potent statin to reduce systemic inflammation and optimal dosing. The following databases will be searched: Medline, Scopus, Web of Science and Cochrane Library of Systematic Reviews. The risk of bias of included studies will be assessed by Cochrane Risk of Bias Tool and Quality Assessment Tool for Quantitative Studies. The quality of studies will be assessed, to show uncertainty, by the Jadad Score. If sufficient evidence is identified, a meta-analysis will be conducted with risk ratios or ORs with 95% CIs in addition to mean differences.

ETHICS AND DISSEMINATION

Ethics approval is not required as no primary data will be collected. Results will be presented at conferences and published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42020169919.

Reduced Protumorigenic Tumor-Associated Macrophages With Statin Use in Premalignant Human Lung Adenocarcinoma

BACKGROUND

Statins have anticancer properties by acting as competitive inhibitors of the mevalonate pathway. They also have anti-inflammatory activity, but their role in suppressing inflammation in a cancer context has not been investigated to date.

METHODS

We have analyzed the relationship between statin use and tumor-associated macrophages (TAMs) in a cohort of 262 surgically resected primary human lung adenocarcinomas. TAMs were evaluated by multiplex immunostaining for the CD68 pan-TAM marker and the CD163 protumorigenic TAM marker followed by digital slide scanning and partially automated quantitation. Links between statin use and tumor stage, virulence, and cancer-specific survival were also investigated in a wider cohort of 958 lung adenocarcinoma cases. All statistical tests were two-sided.

RESULTS

We found a statin dose-dependent reduction in protumorigenic TAMs (CD68+CD163+) in both stromal (P = .021) and parenchymal (P = .003) compartments within regions of in situ tumor growth, but this association was lost in invasive regions. No statistically significant relationship between statin use and tumor stage was observed, but there was a statin dose-dependent shift towards lower histological grade as assessed by growth pattern (P = .028). However, statin use was a predictor of slightly worse cancer-specific survival (P = .032), even after accounting for prognostic variables in a multivariable Cox proportional hazards survival model (hazard ratio = 1.38, 95% confidence interval = 1.04 to 1.84).

CONCLUSIONS

Statin use is associated with reduced numbers of protumorigenic TAMs within preinvasive lung adenocarcinoma and is related to reduced tumor invasiveness, suggesting a chemo-preventive effect in early tumor development. However, invasive disease is resistant to these effects, and no beneficial relationship between statin use and patient outcome is observed.

Statins for neuroprotection in spontaneous intracerebral hemorrhage

Statins, a common drug class for treatment of dyslipidemia, may be neuroprotective for spontaneous intracerebral hemorrhage (ICH) by targeting secondary brain injury pathways in the surrounding brain parenchyma. Statin-mediated neuroprotection may stem from downregulation of mevalonate and its derivatives, targeting key cell signaling pathways that control proliferation, adhesion, migration, cytokine production, and reactive oxygen species generation. Preclinical studies have consistently demonstrated the neuroprotective and recovery enhancement effects of statins, including improved neurologic function, reduced cerebral edema, increased angiogenesis and neurogenesis, accelerated hematoma clearance, and decreased inflammatory cell infiltration. Retrospective clinical studies have reported reduced perihematomal edema, lower mortality rates, and improved functional outcomes in patients who were taking statins before ICH. Several clinical studies have also observed lower mortality rates and improved functional outcomes in patients who were continued or initiated on statins after ICH. Subgroup analysis of a previous randomized trial has raised concerns of a potentially elevated risk of recurrent ICH in patients with previous hemorrhagic stroke who are administered statins. However, most statin trials failed to show an association between statin use and increased hemorrhagic stroke risk. Variable statin dosing, statin use in the pre-ICH setting, and selection biases have limited rigorous investigation of the effects of statins on post-ICH outcomes. Future prospective trials are needed to investigate the association between statin use and outcomes in ICH.

[Preprocedural high - sensitivity C-reactive protein (hsCRP) decrease during intensive atorvastatin therapy: the presumable impact on atherosclerosis progression after coronary stenting]

Proinflammatory status is the risk factor for coronary atherosclerosis progression after coronary stenting (CS). Intensive statin treatment is associated with hsCRP concentration decline.

AIM

to evaluate prognostic significance of preprocedural hsCRP level reduction with intensive statin regimen for coronary atherosclerosis progression during one year after CS.

MATERIALS AND METHODS

We enrolled 102 patients with stable angina who were on list for scheduled CS. Group I (n=37) patients received atorvastatin 80 mg for 7 days before and 3 months after CS with further dose adjustment according to LDL; group II (n=65) patients received atorvastatin 20-40 mg/day for LDL goal achievement. HsCRP level was assessed at baseline, before CS and after 1, 3, 6 and 12 months. Coronary atherosclerosis progression was defined as new ≥50% stenosis or ≥30% increase of ≥20% pre - existing stenosis according to coronary angiography (CA) 1 year after CS.

RESULTS

Baseline concentration of hsCRP was comparable: 0.21 (0.13; 0.38) vs. 0.20 (0.1; 0.44) mg/dl in groups I and II, respectively (p>0.05). In group I significant hsCRP level decrease to 0.14 (0.07; 0.32) mg/dl (p.

Smoking affects gene expression in blood of patients with ischemic stroke

OBJECTIVE

Though cigarette smoking (CS) is a well-known risk factor for ischemic stroke (IS), there is no data on how CS affects the blood transcriptome in IS patients.

METHODS

We recruited IS-current smokers (IS-SM), IS-never smokers (IS-NSM), control-smokers (C-SM), and control-never smokers (C-NSM). mRNA expression was assessed on HTA-2.0 microarrays and unique as well as commonly expressed genes identified for IS-SM versus IS-NSM and C-SM versus C-NSM.

RESULTS

One hundred and fifty-eight genes were differentially expressed in IS-SM versus IS-NSM; 100 genes were differentially expressed in C-SM versus C-NSM; and 10 genes were common to both IS-SM and C-SM (P < 0.01; |fold change| ≥ 1.2). Functional pathway analysis showed the 158 IS-SM-regulated genes were associated with T-cell receptor, cytokine-cytokine receptor, chemokine, adipocytokine, tight junction, Jak-STAT, ubiquitin-mediated proteolysis, and adherens junction signaling. IS-SM showed more altered genes and functional networks than C-SM.

INTERPRETATION

We propose some of the 10 genes that are elevated in both IS-SM and C-SM (GRP15, LRRN3, CLDND1, ICOS, GCNT4, VPS13A, DAP3, SNORA54, HIST1H1D, and SCARNA6) might contribute to increased risk of stroke in current smokers, and some genes expressed by blood leukocytes and platelets after stroke in smokers might contribute to worse stroke outcomes that occur in smokers.

Repurposing simvastatin as a therapy for preterm labor: evidence from preclinical models

Preterm birth (PTB), the leading cause of neonatal morbidity and mortality, urgently requires novel therapeutic agents. Spontaneous PTB, resulting from preterm labor, is commonly caused by intrauterine infection/inflammation. Statins are well-established, cholesterol-lowering drugs that can reduce inflammation and inhibit vascular smooth muscle contraction. We show that simvastatin reduced the incidence of PTB in a validated intrauterine LPS-induced PTB mouse model, decreased uterine proinflammatory mRNA concentrations (IL-6, Cxcl1, and Ccl2), and reduced serum IL-6 concentration. In human myometrial cells, simvastatin reduced proinflammatory mediator mRNA and protein expression (IL-6 and IL-8) and increased anti-inflammatory cytokine mRNA expression (IL-10 and IL-13). Critically, simvastatin inhibited myometrial cell contraction, basally and during inflammation, and reduced phosphorylated myosin light chain concentration. Supplementation with mevalonate and geranylgeranyl pyrophosphate, but not farnesyl pyrophosphate, abolished these anticontractile effects, indicating that the Rho/Rho-associated protein kinase pathway is critically involved. Thus, simvastatin reduces PTB incidence in mice, inhibits myometrial contractions, and exhibits key anti-inflammatory effects, providing a rationale for investigation into the repurposing of statins to treat preterm labor in women.—Boyle, A. K., Rinaldi, S. F., Rossi, A. G., Saunders, P. T. K., Norman, J. E. Repurposing simvastatin as a therapy for preterm labor: evidence from preclinical models.

Leaky brain in neurological and psychiatric disorders: Drivers and consequences

BACKGROUND

The blood-brain barrier acts as a highly regulated interface; its dysfunction may exacerbate, and perhaps initiate, neurological and neuropsychiatric disorders.

METHODS

In this narrative review, focussing on redox, inflammatory and mitochondrial pathways and their effects on the blood-brain barrier, a model is proposed detailing mechanisms which might explain how increases in blood-brain barrier permeability occur and can be maintained with increasing inflammatory and oxidative and nitrosative stress being the initial drivers.

RESULTS

Peripheral inflammation, which is causatively implicated in the pathogenesis of major psychiatric disorders, is associated with elevated peripheral pro-inflammatory cytokines, which in turn cause increased blood-brain barrier permeability. Reactive oxygen species, such as superoxide radicals and hydrogen peroxide, and reactive nitrogen species, such as nitric oxide and peroxynitrite, play essential roles in normal brain capillary endothelial cell functioning; however, chronically elevated oxidative and nitrosative stress can lead to mitochondrial dysfunction and damage to the blood-brain barrier. Activated microglia, redox control of which is mediated by nitric oxide synthases and nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, secrete neurotoxic molecules such as reactive oxygen species, nitric oxide, prostaglandin, cyclooxygenase-2, quinolinic acid, several chemokines (including monocyte chemoattractant protein-1 [MCP-1], C-X-C motif chemokine ligand 1 [CXCL-1] and macrophage inflammatory protein 1α [MIP-1α]) and the pro-inflammatory cytokines interleukin-6, tumour necrosis factor-α and interleukin-1β, which can exert a detrimental effect on blood-brain barrier integrity and function. Similarly, reactive astrocytes produce neurotoxic molecules such as prostaglandin E2 and pro-inflammatory cytokines, which can cause a 'leaky brain'.

CONCLUSION

Chronic inflammatory and oxidative and nitrosative stress is associated with the development of a 'leaky gut'. The following evidence-based approaches, which address the leaky gut and blood-brain barrier dysfunction, are suggested as potential therapeutic interventions for neurological and neuropsychiatric disorders: melatonin, statins, probiotics containing Bifidobacteria and Lactobacilli, N-acetylcysteine, and prebiotics containing fructo-oligosaccharides and galacto-oligosaccharides.

Immunotropic Effects and Proposed Mechanism of Action for 3-Hydroxy-3-methylglutaryl-coenzyme A Reductase Inhibitors (Statins)

Inhibitors of HMG-CoA reductase (statins) are the major group of lipid-lowering drugs. Along with hypocholesterolemic activity, statins exhibit anti-inflammatory and immunomodulatory properties that expand their clinical use, particularly, in the treatment of chronic inflammatory and autoimmune disorders. In this review, we critically analyze the data of statin effects on immune cells (e.g., monocytes and T cells) involved in the development of atherosclerosis and other chronic inflammatory diseases. We (i) discuss the properties of statins and routes of cell entry, as well as their major intracellular targets; (ii) evaluate the data on the effects of statins on the subset composition of circulatory monocytes, ability of monocytes to migrate to the site of inflammation (cell motility and expression of adhesion molecules and chemokine receptors), production of cytokines, matrix metalloproteinases, and reactive oxygen species by monocytes/macrophages, and antigen-presenting activity in peripheral blood monocyte-derived dendritic cells; and (iii) summarize the data on the regulation of proliferation and differentiation of various CD4+ T cell subsets (type 1/2/17 helper T cells and regulatory T cells) by statins.

Management and Prevention of Saphenous Vein Graft Failure: A Review

Coronary artery bypass grafting (CABG) remains a vital treatment for patients with multivessel coronary artery disease (CAD), especially diabetics. The long-term benefit of the internal thoracic artery graft is well established and remains the gold standard for revascularization of severe CAD. It is not always possible to achieve complete revascularization through arterial grafts, necessitating the use of saphenous vein grafts (SVG). Unfortunately, SVGs do not have the same longevity, and their failure is associated with significant adverse cardiac outcomes and mortality. This paper reviews the pathogenesis of SVG failure, highlighting the difference between early, intermediate, and late failure. It also addresses the different surgical techniques that affect the incidence of SVG failure, as well as the medical and percutaneous prevention and treatment options in contemporary practice.

Modulation of Chemokine Receptor Function by Cholesterol: New Prospects for Pharmacological Intervention

Chemokine receptors are seven transmembrane-domain receptors belonging to class A of G-protein-coupled receptors (GPCRs). The receptors together with their chemokine ligands constitute the chemokine system, which is essential for directing cell migration and plays a crucial role in a variety of physiologic and pathologic processes. Given the importance of orchestrating cell migration, it is vital that chemokine receptor signaling is tightly regulated to ensure appropriate responses. Recent studies highlight a key role for cholesterol in modulating chemokine receptor activities. The steroid influences the spatial organization of GPCRs within the membrane bilayer, and consequently can tune chemokine receptor signaling. The effects of cholesterol on the organization and function of chemokine receptors and GPCRs in general include direct and indirect effects (Fig. 1). Here, we review how cholesterol and some key metabolites modulate functions of the chemokine system in multiple ways. We emphasize the role of cholesterol in chemokine receptor oligomerization, thereby promoting the formation of a signaling hub enabling integration of distinct signaling pathways at the receptor-membrane interface. Moreover, we discuss the role of cholesterol in stabilizing particular receptor conformations and its consequence for chemokine binding. Finally, we highlight how cholesterol accumulation, its deprivation, or cholesterol metabolites contribute to modulating cell orchestration during inflammation, induction of an adaptive immune response, as well as to dampening an anti-tumor immune response.

PET/CT Imaging of Chemokine Receptors in Inflammatory Atherosclerosis Using Targeted Nanoparticles

Atherosclerosis is inherently an inflammatory process that is strongly affected by the chemokine-chemokine receptor axes regulating the trafficking of inflammatory cells at all stages of the disease. Of the chemokine receptor family, some specifically upregulated on macrophages play a critical role in plaque development and may have the potential to track plaque progression. However, the diagnostic potential of these chemokine receptors has not been fully realized. On the basis of our previous work using a broad-spectrum peptide antagonist imaging 8 chemokine receptors together, the purpose of this study was to develop a targeted nanoparticle for sensitive and specific detection of these chemokine receptors in both a mouse vascular injury model and a spontaneously developed mouse atherosclerosis model.

METHODS

The viral macrophage inflammatory protein-II (vMIP-II) was conjugated to a biocompatible poly(methyl methacrylate)-core/polyethylene glycol-shell amphiphilic comblike nanoparticle through controlled conjugation and polymerization before radiolabeling with (64)Cu for PET imaging in an apolipoprotein E-deficient (ApoE(-/-)) mouse vascular injury model and a spontaneous ApoE(-/-) mouse atherosclerosis model. Histology, immunohistochemistry, and real-time reverse transcription polymerase chain reaction were performed to assess the plaque progression and upregulation of chemokine receptors.

RESULTS

The chemokine receptor-targeted (64)Cu-vMIP-II-comb showed extended blood retention and improved biodistribution. PET imaging showed specific tracer accumulation at plaques in ApoE(-/-) mice, confirmed by competitive receptor blocking studies and assessment in wild-type mice. Histopathologic characterization showed the progression of plaque including size and macrophage population, corresponding to the elevated concentration of chemokine receptors and more importantly increased PET signals.

CONCLUSION

This work provides a useful nanoplatform for sensitive and specific detection of chemokine receptors to assess plaque progression in mouse atherosclerosis models.

Statin modulation of monocyte phenotype and function: implications for HIV-1-associated neurocognitive disorders

HIV-1-associated neurocognitive disorder (HAND) remains a persistent problem despite antiretroviral therapy (ART), largely a result of continued inflammation in the periphery and the brain and neurotoxin release from activated myeloid cells in the CNS. CD14+CD16+ inflammatory monocytes, expanded in HIV infection, play a central role in the pathogenesis of HAND and have parallels with monocyte-dependent inflammatory mechanisms in atherosclerosis. Statins, through their HMG-CoA reductase inhibitor activity, have pleiotropic immunomodulatory properties that contribute to their benefit in atherosclerosis beyond lipid lowering. Here, we investigated whether statins would modulate the monocyte phenotype and function associated with HIV-1 neuropathogenesis. Treatment ex vivo with simvastatin and atorvastatin reduced the proportion of CD16+ monocytes in peripheral blood mononuclear cells, as well as in purified monocytes, especially CD14++CD16+ "intermediate" monocytes most closely associated with neurocognitive disease. Statin treatment also markedly reduced expression of CD163, which is also linked to HAND pathogenesis. Finally, simvastatin inhibited production of monocyte chemoattractant protein-1 (MCP-1) and other inflammatory cytokines following LPS stimulation and reduced monocyte chemotaxis in response to MCP-1, a major driver of myeloid cell accumulation in the CNS in HAND. Together, these findings suggest that statin drugs may be useful to prevent or reduce HAND in HIV-1-infected subjects on ART with persistent monocyte activation and inflammation.

Simvastatin increases the antineoplastic actions of paclitaxel carried in lipid nanoemulsions in melanoma-bearing mice

PURPOSE

Lipid nanoemulsions (LDEs) that bind to low-density lipoprotein (LDL) receptors used as carriers of paclitaxel (PTX) can decrease toxicity and increase PTX antitumoral action. The administration of simvastatin (Simva), which lowers LDL-cholesterol, was tested as an adjuvant to commercial PTX and to PTX associated with LDE (LDE-PTX).

MATERIALS AND METHODS

B16F10 melanoma-bearing mice were treated with saline solution or LDE (controls), Simva, PTX, PTX and Simva, LDE-PTX, and LDE-PTX and Simva: PTX dose 17.5 μmol/kg (three intraperitoneal injections, 3 alternate days): Simva 50 mg/kg/day by gavage, 9 consecutive days.

RESULTS

Compared with saline controls, 95% tumor-growth inhibition was achieved by LDE-PTX and Simva, 61% by LDE-PTX, 44% by PTX and Simva, and 43% by PTX. Simva alone had no effect. Metastasis developed in only 37% of the LDE-PTX and Simva, 60% in LDE-PTX, and 90% in PTX and Simva groups. Survival rates were higher in LDE-PTX and Simva and in LDE-PTX groups. The LDE-PTX and Simva group presented tumors with reduced cellular density and increased collagen fibers I and III. Tumors from all groups showed reduction in immunohistochemical expression of ICAM, MCP-1, and MMP-9; LDE-PTX and Simva presented the lowest MMP-9 expression. Expression of p21 was increased in the Simva, LDE-PTX, and LDE-PTX and Simva groups. In the Simva and LDE-PTX and Simva groups, expression of cyclin D1, a proliferation and survival promoter of tumor cells, was decreased. Therapy with LDE-PTX and Simva showed negligible toxicity compared with PTX and Simva, which resulted in weight loss and myelosuppression.

CONCLUSION

Simva increased the antitumor activity of PTX carried in LDE but not of PTX commercial presentation, possibly because statins increase the expression of LDL receptors that internalize LDE-PTX.

Change of concept about the regulation of angiotensin II-induced monocyte chemoattractant protein-1 production in human endothelial cells

AIMS

Some intriguing clinical observations about the anti-inflammatory effects of angiotensin type 1 (AT1) receptor blockers and angiotensin converting enzyme inhibitors in cardiovascular patients brought us to study the signalling pathways which lead to angiotensin II (ANG)-induced monocyte chemoattractant protein-1 (MCP-1) production in human endothelial cells.

METHODS

MCP-1 production in human umbilical vein endothelial cells (HUVECs) under treatments with ANG, AT1 and angiotensin type 2 (AT2) receptor blockers and pravastatin was measured by ELISA. The expression of AT1 and AT2 receptors and NADPH oxidase catalytic subunits (NOX 1-5) was analysed at mRNA and protein levels. Nuclear factor-kappa B (NF-κB) activation was studied by p65 subunit translocation to the cellular nucleus. Cell viability was tested by the MTT method. Nox4 subcellular distribution was analysed by subcellular protein fractionation and by immunoprecipitation followed by matrix-assisted laser desorption/ionization mass spectrometry analysis.

RESULTS

ANG-induced MCP-1 production was mediated by AT2 receptor, but not AT1 receptor in HUVECs in culture, which in turn activated NF-κB, promoting p65 subunit translocation to the nucleus. Reactive oxygen species produced by NADPH oxidase participated in this activation, mainly by the Nox4 subunit, ubiquitously expressed in all the compartments of HUVECs. Pravastatin inhibited ANG-induced MCP-1 production.

CONCLUSIONS

Our results support that ANG-induced MCP-1 production in HUVECs is mediated by AT2 instead AT1 receptor activation, which in turn activates NF-κB involving reactive oxygen species produced by the NADPH oxidase complex. Statins can also block ANG-induced MCP-1 production, probably by their inhibitory effects on NADPH oxidase activity.

Rosuvastatin enhances anti-inflammatory and inhibits pro-inflammatory functions in cultured microglial cells

Microglial activation results in profound morphological, functional and gene expression changes that affect the pro- and anti-inflammatory mechanisms of these cells. Although statins have beneficial effects on inflammation, they have not been thoroughly investigated for their ability to affect microglial functions. Therefore the effects of rosuvastatin, one of the most commonly prescribed drugs in cardiovascular therapy, either alone or in combination with bacterial lipopolysaccharide (LPS), were profiled in pure microglial cultures derived from the forebrains of 18-day-old rat embryos. To reveal the effects of rosuvastatin on a number of pro- and anti-inflammatory mechanisms, we performed morphometric, functional and gene expression studies relating to cell adhesion and proliferation, phagocytosis, pro- and anti-inflammatory cytokine (IL-1β, tumor necrosis factor α (TNF-α) and IL-10, respectively) production, and the expression of various inflammation-related genes, including those related to the above morphological parameters and cellular functions. We found that microglia could be an important therapeutic target of rosuvastatin. In unchallenged (control) microglia, rosuvastatin inhibited proliferation and cell adhesion, but promoted microspike formation and elevated the expression of certain anti-inflammatory genes (Cxcl1, Ccl5, Mbl2), while phagocytosis or pro- and anti-inflammatory cytokine production were unaffected. Moreover, rosuvastatin markedly inhibited microglial activation in LPS-challenged cells by affecting both their morphology and functions as it inhibited LPS-elicited phagocytosis and inhibited pro-inflammatory cytokine (IL-1β, TNF-α) production, concomitantly increasing the level of IL-10, an anti-inflammatory cytokine. Finally, rosuvastatin beneficially and differentially affected the expression of a number of inflammation-related genes in LPS-challenged cells by inhibiting numerous pro-inflammatory and stimulating several anti-inflammatory genes. Since the microglia could elicit pro-inflammatory responses leading to neurodegeneration, it is important to attenuate such mechanisms and promote anti-inflammatory properties, and develop prophylactic therapies. By beneficially regulating both pro- and anti-inflammatory microglial functions, rosuvastatin may be considered as a prophylactic agent in the prevention of inflammation-related neurological disorders.

Combined treatment with bexarotene and rosuvastatin reduces angiotensin-II-induced abdominal aortic aneurysm in apoE(-/-) mice and angiogenesis

BACKGROUND AND PURPOSE

Abdominal aortic aneurysm (AAA) is a degenerative vascular disease associated with angiogenesis. Bexarotene is a retinoid X receptor (RXR) ligand with anti-angiogenic activity. Statins also exert anti-angiogenic activity and activate PPARs. Because RXR ligands form permissive heterodimers with PPARs and a single anti-angiogenic drug may not be sufficient to combat the wide array of angiogenic factors produced during AAA, we evaluated the effect of combined low doses of bexarotene and rosuvastatin in a mouse model of AAA.

EXPERIMENTAL APPROACH

The effect of the combined treatment was investigated in a murine model of angiotensin II-induced AAA in apoE(-/-) mice. This combination therapy was also evaluated in in vivo (Matrigel plug assay) and in vitro (endothelial cell differentiation assay) models of angiogenesis as well as the underlying mechanisms involved.

KEY RESULTS

Co-treatment with bexarotene plus rosuvastatin reduced aneurysm formation, inflammation and neovascularization compared with each single treatment. In HUVEC, the combination of suboptimal concentrations of bexarotene and rosuvastatin inhibited angiotensin II-induced morphogenesis, proliferation and migration. These effects were accompanied by diminished production of pro-angiogenic chemokines (CXCL1, CCL2 or CCL5) and VEGF, and seemed to be mediated by RXRα/PPARα and RXRα/PPARγ activation. This combined therapy reduced the activation of members of the downstream PI3K pathway (Akt/mTOR and p70S6K1) in vivo and in vitro.

CONCLUSIONS AND IMPLICATIONS

The combination of RXR agonists with statins at low doses synergistically interferes with the signalling pathways that modulate inflammation and angiogenesis and may constitute a new and safer therapeutic treatment for the control of AAA.

Metformin enhances nitric oxide production and diminishes Rho kinase activity in rats with hyperlipidemia

BACKGROUND

Rho kinase over-activation is associated with nitric oxide (NO) reduction and atherosclerosis. Metformin is favorable for endothelial function improvement and cardiovascular outcomes. Whether cardio-protective effect of metformin is associated with Rho kinase activity is unknown.

METHODS

Hyperlipidemia model of rats were established accordingly. Thereafter, medical interventions in terms of atorvastatin, metformin or combined therapy were administered for 4 weeks. Laboratory parameters were compared among each groups at initial, 6 weeks of high-fat and high-cholesterol diet administration, and 4 weeks of medical intervention. Lineal regression analyses were performed.

RESULTS

No significant difference of laboratory parameters was observed initially. Six weeks of high-fat and high-cholesterol diet administration, serum levels of cholesterol, C-reactive protein (CRP) level, and Rho kinase activity were significantly increased while NO production was concomitantly reduced in comparison to the sham group. After 4 weeks of medical intervention, CRP level and Rho kinase activity were profoundly diminished while NO production was significantly enhanced in the atorvastatin and metformin groups, and these benefits were further enhanced with combined therapy. Lineal regression analyses showed that Rho kinase activity was negatively correlated with NO production but positively correlated with CRP level.

CONCLUSION

In rats with hyperlipidemia, metformin and atorvastatin therapy is favorable for NO production and CRP reduction, which might be associated with Rho kinase activity decrease.

Contribution of homeostatic chemokines CCL19 and CCL21 and their receptor CCR7 to coronary artery disease

OBJECTIVE

Our aim was to identify the role of the homeostatic chemokines CCL19 and CCL21 and their common receptor CCR7 in atherogenesis and to study the relationships between CCL19, CCL21, and CCR7 gene variants and coronary artery disease in a Chinese Han population.

APPROACH AND RESULTS

Immunohistochemical analysis of samples with atherosclerosis of various stages showed increased CCL19, CCL21, and CCR7 expression in atherosclerotic coronary plaques compared with nonatherosclerotic controls. Expression levels increased in positive correlation with coronary lesion stage. Cell adhesion assays confirmed that CCL19 promoted monocyte adhesion, which was induced by CCR7, to human umbilical vein endothelial cells, an effect partially antagonized by atorvastatin. After the human umbilical vein endothelial cells were treated with CCR7-neutralizing antibody, both CCL19- and CCL21-induced monocyte to human umbilical vein endothelial cell migration and CCL19-induced monocyte to human umbilical vein endothelial cell adhesion were abolished. The associations between genetic variants of CCL19, CCL21, CCR7, and coronary artery disease in a Chinese Han population were determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The following single nucleotide polymorphisms were associated with coronary artery disease: CCL19 rs2227302, CCL21 rs2812377, and CCR7 rs588019. Individuals with the CCL19 rs2227302 T allele or CCL21 rs2812377 G allele had higher plasma CCL19 levels than those with C/C genotype and higher CCL21 levels than those with T/T genotype in both case and control subjects.

CONCLUSION

CCL19/CCL21-CCR7 is a novel homeostatic chemokine system that modulates human monocyte adhesion and migration, promoting atherogenesis. It is associated with coronary artery disease risk in Chinese Han individuals. These data suggest that the CCL19/CCL21-CCR7 axis plays an important role in atherosclerosis progression.

Circulating monocyte chemotactic protein 1 (MCP-1), vascular cell adhesion molecule 1 (VCAM-1) and angiogenin in type 2 diabetic patients treated with statins in low doses

Statins are known as agents promoting a biphasic dose-dependent effect on angiogenesis under experimental conditions. Dysregulation of angiogenesis plays an important role in the development of atherosclerosis and it may be affected by metabolic factors. The aim of this research was to explain how low doses of statins modify serum concentrations of pro-angiogenic factors MCP-1 and angiogenin in type 2 diabetic patients. Measurements of metabolic control parameters were performed in 30 patients with type 2 diabetes treated with low doses of statin, and in 34 statin-free patients with type 2 diabetes. The serum levels of MCP-1 and VCAM-1 in statin-treated patients were lower than those of the statin-free group. ANCOVA results revealed that these effects were dependent only on the use of statins. In type 2 diabetic subjects, overall positive correlation was found between total cholesterol or LDL serum concentration and MCP-1 serum level. The angiogenin concentration in the serum did not show differences and was comparable in both groups. The angiogenin serum level correlated negatively with HDL, LDL and with HbA1c. Multivariate regression analysis indicated that angiogenin serum levels in type 2 diabetic patients were determined mainly by HbA1c, HDL-cholesterol and diabetes duration. It has been shown that statins used in low doses in type 2 diabetic subjects decrease MCP-1 and VCAM-1serum levels, most likely due to the statins-related effect on the lipid profile, while angiogenin serum levels in this group are determined rather by the current metabolic control.

Thiazolidinedione-independent activation of peroxisome proliferator-activated receptor γ is a potential target for diabetic macrovascular complications

Macrovascular complications are responsible for the high morbidity and mortality in patients with diabetes. Peroxisome proliferator‐activated receptor γ (PPARγ) plays a central role in the process of adipocyte differentiation and insulin sensitization, and also possesses anti‐atherogenic effects. Recently, some statins, angiotensin II type 1 receptor blockers and calcium channel blockers have been reported to activate PPARγ. However, the impact of PPARγ activation on diabetic macrovascular complications is not fully understood. It has been reported that the activation of PPARγ by thiazolidinediones induces anti‐atherogenic effects in vascular cells, including monocytes/macrophages, endothelial cells and smooth muscle cells, in atherosclerotic animal models and in clinical studies. We have reported that hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), which are used for treatment of hypercholesterolemia, activate PPARγ and mediate anti‐atherogenic effects through PPARγ activation in macrophages. Also, telmisartan, an angiotensin type I receptor blocker, has been reported to have anti‐atherogenic effects through PPARγ activation. Furthermore, we have reported that nifedipine, a dihydropyridine calcium channel blocker, can activate PPARγ, thereby mediating anti‐atherogenic effects in macrophages. Therefore, statin therapy and part of anti‐hypertensive therapy might produce beneficial effects through PPARγ activation in hypercholesterolemic and/or hypertensive patients with diabetes, and PPARγ might be a therapeutic target for diabetic macrovascular complications. In the present review, we focus on the anti‐atherogenic effects of PPARγ and suggest potential therapeutic approaches to prevent diabetic macrovascular complications. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00182.x, 2012)

Novel role of Cdc42 and RalA GTPases in TNF-α mediated secretion of CCL2

Transendothelial migration of autoreactive leukocytes into peripheral nerves is an early pathological hallmark of acute inflammatory demyelinating polyneuropathy (AIDP), a North American and European variant of Guillain-Barré Syndrome. Whereas the clinical management of AIDP is currently limited to non-selective immune modulating therapies, recent experimental studies support selective targeting of leukocyte trafficking as a promising alternative therapeutic strategy. Here, using a combination of targeted siRNA knockdown and pharmacological inhibitors, we report a novel role of both Cdc42 and RalA GTPases in facilitating TNF-α mediated CCL2 trafficking and release from immortalized rat peripheral nerve microvascular endoneurial endothelial cells. These findings raise interest in Cdc42 and RalA GTPases as potential therapeutic targets for the management of autoimmune inflammatory peripheral nerve disease.

Cdc42 GTPases facilitate TNF-α-mediated secretion of CCL2 from peripheral nerve microvascular endoneurial endothelial cells

Trafficking of autoreactive leukocytes across the blood-nerve barrier and into peripheral nerves is an early pathological hallmark of Guillain-Barré syndrome (GBS). Tumor necrosis factor-α (TNF-α), a proinflammatory cytokine, promotes transendothelial migration by upregulating endothelial expression of inflammatory mediators, including CCL2, a chemokine implicated in GBS. We sought to determine the mechanism by which TNF-α induces expression and secretion of CCL2 from peripheral nerve microvascular endoneurial endothelial cells (PNMECs). Expression of CCL2 mRNA and protein in quiescent PNMEC cultures was minimal. In contrast, cultures treated with TNF-α exhibited increased CCL2 mRNA and protein content, as well as protein secretion. Simvastatin significantly attenuated TNF-α-induced CCL2 secretion without affecting CCL2 mRNA or protein expression. Co-incubation with geranylgeranyl pyrophosphate, but not farnesyl pyrophosphate, prevented the effect of simvastatin. By comparison, inhibiting protein isoprenylation with GGTI-298, but not FTI-277, mimicked the effect of simvastatin and significantly attenuated transendothelial migration in vitro. Inhibition of the monomeric GTPase Cdc42, but not Rac1 or RhoA-C, attenuated TNF-α-mediated CCL2 secretion. TNF-α-mediated trafficking of autoreactive leukocytes into peripheral nerves during GBS may proceed by a mechanism that involves Cdc42-facilitated secretion of CCL2.

Increased proatherogenic monocyte-platelet cross-talk in monocyte subpopulations of patients with stable coronary artery disease

BACKGROUND

Monocytes and platelets are important cellular mediators of atherosclerosis. Human monocytes can be divided into CD14(++) CD16(-) , CD14(++) CD16(+) and CD14(+) CD16(++) cells, which differ in their functional properties. The aim of this study was to examine monocyte subset distribution, monocyte-platelet aggregate (MPA) formation and expression of CCR5, the receptor of the platelet-derived chemokine CCL5, and to determine whether these parameters are altered in individuals with coronary atherosclerosis.

METHODS

Peripheral blood cells from 64 healthy blood donors (HBDs) and 60 patients with stable coronary artery disease (CAD) were stained with antibodies against CD14, CD16, CD42b and CCR5 and analysed by flow cytometry. Circulating CCL5 levels were determined using an enzyme-linked immunosorbent assay.

RESULTS

In patients with CAD, the relative proportion of the CD14(++) CD16(-) monocyte subset was elevated (P < 0.05) and of the CD14(+) CD16(++) subset was reduced (P < 0.001) compared with the HBD group. Furthermore, MPA formation significantly increased in patients with CAD in all three monocyte subsets. In both study groups, the majority of CCR5(+) cells was detected in CD14(++) CD16(+) monocytes (P < 0.001 versus CD14(++) CD16(-) and CD14(+) CD16(++) ), although the CCR5(+) monocyte number was reduced in patients with CAD (CD14(++) CD16(-) /CD14(+) CD16(++) , P < 0.001; CD14(++) CD16(+) , P < 0.05) compared with the HBD group, particularly in those who were not taking statins. Ex vivo incubation of monocytes from HBDs with plasma from patients with CAD also decreased CCR5(+) expression (P < 0.05 versus plasma from HBDs). Serum CCL5 levels were similar in both groups.

CONCLUSIONS

The increased monocyte-platelet cross-talk in patients with CAD might have contributed to atherosclerosis progression. The decreased CCR5(+) monocyte numbers in patients with CAD could have resulted from CCR5(+) cell recruitment into atherosclerotic lesions or CCR5 downregulation in response to circulating factors.

Antiapoptotic effect of simvastatin ameliorates myocardial ischemia/reperfusion injury

Background. Myocardial ischemial reperfusion represents a clinically relevant problem associated with thrombolysis, angioplasty, and coronary bypass surgery. Injury of myocardium due to ischemial reperfusion includes cardiac contractile dysfunction, arrhythmias, and irreversible myocytes damage. These changes are considered to be the consequence of imbalance between the formation of oxidants and the availability of endogenous antioxidants in the heart. Objective. This study was undertaken to investigate the potential role of Simvastatin in the amelioration of myocardial I/R injury induced by ligation of coronary artery in a rat model. Materials and Methods. Adult male Swiss Albino rats were randomized into 4 equal groups. Group (1): sham group: rats underwent the same anesthetic and surgical procedures as those in the control group except ligation of LAD coronary artery, group (2): control group: rats were subjected to regional ischemia for 25 min and reperfusion for 2 hours by ligation of LAD coronary artery, group (3): control vehicle group: rats received vehicle of Simvastatin (normal saline) via IP injection and were subjected to regional ischemia for 25 min and reperfusion for 2 hours by ligation of LAD coronary artery, group (4): Simvastatin treated group: rats were pretreated with Simvastatin 1 mg/kg i.p. 1 hr before ligation of LAD coronary artery. At the end of experiment (2 hr of reperfusion), blood samples were collected from the heart for the measurement of plasma level of cardiac troponin I (cTnI). After that the heart was harvested and divided into 3 parts; one part was used for measurement of apoptosis, another part was homogenized for the measurement of tissue tumor necrosis factor- α (TNF- α ), interleukin-1 β (IL-1 β ), interleukin-6, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1 α , and the last part for histopathology study. Results. Compared with the sham group, levels of myocardial TNF- α and IL-1 β , IL-6, MCP-1, and MIP-1 α and plasma cTnI were increased (P < 0.05). Histologically, all rats in control group showed significant (P < 0.05) cardiac injury. Furthermore, all rats in control group showed significant (P < 0.05) apoptosis. Simvastatin significantly counteracted the increase in myocardium level of TNF- α , IL-1B, IL-6, MCP-1 and MIP-1 α , plasma cTnI, and apoptosis (P < 0.05). Histological analysis revealed that Simvastatin markedly reduced (P < 0.05) the severity of heart injury in the rats that underwent LAD ligation procedure. Conclusions. The results of the present study reveal that Simvastatin may ameliorate myocardial I/R injury in rats via interfering with inflammatory reactions and apoptosis which were induced by I/R injury.

International Union of Basic and Clinical Pharmacology. [corrected]. LXXXIX. Update on the extended family of chemokine receptors and introducing a new nomenclature for atypical chemokine receptors

Sixteen years ago, the Nomenclature Committee of the International Union of Pharmacology approved a system for naming human seven-transmembrane (7TM) G protein-coupled chemokine receptors, the large family of leukocyte chemoattractant receptors that regulates immune system development and function, in large part by mediating leukocyte trafficking. This was announced in Pharmacological Reviews in a major overview of the first decade of research in this field [Murphy PM, Baggiolini M, Charo IF, Hébert CA, Horuk R, Matsushima K, Miller LH, Oppenheim JJ, and Power CA (2000) Pharmacol Rev 52:145-176]. Since then, several new receptors have been discovered, and major advances have been made for the others in many areas, including structural biology, signal transduction mechanisms, biology, and pharmacology. New and diverse roles have been identified in infection, immunity, inflammation, development, cancer, and other areas. The first two drugs acting at chemokine receptors have been approved by the U.S. Food and Drug Administration (FDA), maraviroc targeting CCR5 in human immunodeficiency virus (HIV)/AIDS, and plerixafor targeting CXCR4 for stem cell mobilization for transplantation in cancer, and other candidates are now undergoing pivotal clinical trials for diverse disease indications. In addition, a subfamily of atypical chemokine receptors has emerged that may signal through arrestins instead of G proteins to act as chemokine scavengers, and many microbial and invertebrate G protein-coupled chemokine receptors and soluble chemokine-binding proteins have been described. Here, we review this extended family of chemokine receptors and chemokine-binding proteins at the basic, translational, and clinical levels, including an update on drug development. We also introduce a new nomenclature for atypical chemokine receptors with the stem ACKR (atypical chemokine receptor) approved by the Nomenclature Committee of the International Union of Pharmacology and the Human Genome Nomenclature Committee.

Antithrombotic actions of statins involve PECAM-1 signaling

Statins are widely prescribed cholesterol-lowering drugs that are a first-line treatment of coronary artery disease and atherosclerosis, reducing the incidence of thrombotic events such as myocardial infarction and stroke. Statins have been shown to reduce platelet activation, although the mechanism(s) through which this occurs is unclear. Because several of the characteristic effects of statins on platelets are shared with those elicited by the inhibitory platelet adhesion receptor PECAM-1 (platelet endothelial cell adhesion molecule-1), we investigated a potential connection between the influence of statins on platelet function and PECAM-1 signaling. Statins were found to inhibit a range of platelet functional responses and thrombus formation in vitro and in vivo. Notably, these effects of statins on platelet function in vitro and in vivo were diminished in PECAM-1(-/-) platelets. Activation of PECAM-1 signaling results in its tyrosine phosphorylation, the recruitment and activation of tyrosine phosphatase SHP-2, the subsequent binding of phosphoinositol 3-kinase (PI3K), and diminished PI3K signaling. Statins resulted in the stimulation of these events, leading to the inhibition of Akt activation. Together, these data provide evidence for a fundamental role of PECAM-1 in the inhibitory effects of statins on platelet activation, which may explain some of the pleiotropic actions of these drugs.

Potential role for anti-angiogenic therapy in abdominal aortic aneurysms

OBJECTIVE

Abdominal aortic aneurysm (AAA) is a condition that mainly affects elderly men. At present, there is no effective medical therapy that can retard aneurysm growth or prevent aneurysm rupture. There is evidence that angiogenesis within the wall of an aortic aneurysm may play key roles in aneurysm progression as well as rupture. The use of anti-angiogenic therapy as potential medical therapy in AAA is a promising strategy but has never been studied in detail.

DESIGN

This paper discusses the basic mechanisms of angiogenesis, the role played by angiogenesis in aortic aneurysms and the potential therapeutic role of anti-angiogenic drugs against aneurysm expansion or rupture.

RESULTS

Angiogenesis is a multi-step process which is fundamental for growth and differentiation of various tissues within a multi-cellular organism. Hypoxia and inflammation are key stimuli for activation of neoangiogenesis. Investigations in both human tissues and animal models of AAA have shown that angiogenesis is a pathological hallmark of AAA and appears to play a role in the development and progression of the condition. Pre-clinical studies have shown that anti-angiogenic drugs can potentially be effective in reducing the intensity of aneurysm formation, suggesting that such drugs may potentially be useful as novel drug therapy for AAA in humans.

CONCLUSION

Current evidence suggests that angiogenesis contributes to the destructive processes within aneurysmal aortic wall. As novel drug therapy for aortic aneurysms (for use in humans) is still eluding researchers, anti-angiogenic pathway appears to be an attractive approach.

Atorvastatin in stable angina patients lowers CCL2 and ICAM1 expression: pleiotropic evidence from plasma mRNA analyses

OBJECTIVE

Statin pleiotropy is still an evolving concept, and the lack of clarity on this subject is due at least in part to the lack of a definitive biomarker for statin pleiotropy. Using plasma mRNA analysis as a novel research tool for the non-invasive in vivo assessment of gene expression in vascular beds, we hypothesised that atorvastatin lowers the plasma mRNA level from statin pleiotropy-target genes, and the reduction is independent of the reduction of low-density lipoprotein cholesterol (LDL-C).

DESIGN AND METHODS

Forty-four patients with stable angina received atorvastatin therapy (20 mg/day, 10 weeks). Plasma chemokine (C-C motif) ligand 2 (CCL2) and intercellular adhesion molecule-1 (ICAM1) mRNA levels and their protein concentrations (MCP-1, sICAM-1) were analysed before and after the treatment. Plasma vascular adhesion molecule-1 (sVCAM-1) concentrations were also analysed.

RESULTS

Atorvastatin lowered plasma mRNA levels (CCL2: -31.76%, p=0.037; ICAM1: -34.09%, p<0.001) and MCP-1 protein concentration (-18.88%, p=0.008) but did not lower sICAM-1 and sVCAM-1 protein concentrations, and the decreases appeared to be independent from the lowering of LDL-C. The plasma mRNA levels correlated with their protein concentrations following statin treatment only.

CONCLUSION

Our results significantly strengthen the clinical evidence in support of statin pleiotropy. Furthermore, this unique simultaneous measurement of plasma mRNAs and their protein concentrations offers an advanced non-invasive in vivo assessment of the circulation pathology.

Hypercholesterolemia links hematopoiesis with atherosclerosis

Atherosclerosis is characterized by the progressive accumulation of lipids and leukocytes in the arterial wall. Leukocytes such as macrophages accumulate oxidized lipoproteins in the growing atheromata and give rise to foam cells, which can then contribute to the necrotic core of lesions. Lipids and leukocytes also interact in other important ways. In experimental models, systemic hypercholesterolemia is associated with severe neutrophilia and monocytosis. Recent evidence indicates that cholesterol-sensing pathways control the proliferation of hematopoietic stem-cell progenitors. Here we review some of the studies that are forging this particular link between metabolism and inflammation, and propose several strategies that could target this axis for the treatment of cardiovascular disease.

Targeting GGTase-I activates RHOA, increases macrophage reverse cholesterol transport, and reduces atherosclerosis in mice

BACKGROUND

Statins have antiinflammatory and antiatherogenic effects that have been attributed to inhibition of RHO protein geranylgeranylation in inflammatory cells. The activity of protein geranylgeranyltransferase type I (GGTase-I) is widely believed to promote membrane association and activation of RHO family proteins. However, we recently showed that knockout of GGTase-I in macrophages activates RHO proteins and proinflammatory signaling pathways, leading to increased cytokine production and rheumatoid arthritis. In this study, we asked whether the increased inflammatory signaling of GGTase-I-deficient macrophages would influence the development of atherosclerosis in low-density lipoprotein receptor-deficient mice.

METHODS AND RESULTS

Aortic lesions in mice lacking GGTase-I in macrophages (Pggt1b▵/▵) contained significantly more T lymphocytes than the lesions in controls. Surprisingly, however, mean atherosclerotic lesion area in Pggt1b▵/▵ mice was reduced by ≈60%. GGTase-I deficiency reduced the accumulation of cholesterol esters and phospholipids in macrophages incubated with minimally modified and acetylated low-density lipoprotein. Analyses of GGTase-I-deficient macrophages revealed upregulation of the cyclooxygenase 2-peroxisome proliferator-activated-γ pathway and increased scavenger receptor class B type I- and CD36-mediated basal and high-density lipoprotein-stimulated cholesterol efflux. Lentivirus-mediated knockdown of RHOA, but not RAC1 or CDC42, normalized cholesterol efflux. The increased cholesterol efflux in cultured cells was accompanied by high levels of macrophage reverse cholesterol transport and slightly reduced plasma lipid levels in vivo.

CONCLUSIONS

Targeting GGTase-I activates RHOA and leads to increased macrophage reverse cholesterol transport and reduced atherosclerosis development despite a significant increase in inflammation.

In vivo imaging of leukocyte recruitment to the atheroprone femoral artery reveals anti-inflammatory effects of rosuvastatin

Objective. To monitor the anti-inflammatory effect of rosuvastatin in leukocyte endothelial interactions in the atheroprone femoral artery in vivo. Methods and Results. Male Apolipoprotein E null mice (ApoE−/− mice, 6 weeks old) were fed a high-fat diet (20% fat, 1.25% cholesterol) with or without the HMG CoA reductase inhibitor rosuvastatin (10 mg/kg/day) for 6 weeks. Significant leukocyte adhesion was observed in the femoral artery of ApoE−/− mice, but not of wild type mice, in the absence of rosuvastatin. Interestingly, no obvious plaque formation was observed in the artery at this time point. The number of adherent leukocytes was dramatically diminished in ApoE−/− mice treated with rosuvastatin. DHE-associated oxidative stress and the expression of gp91-phox, a component of NADPH oxidase, were induced in ApoE−/− mice and were abolished by rosuvastatin treatment. Conclusion. Our data documented leukocyte recruitment prior to lipid accumulation and subsequent inhibition by rosuvastatin. The underlying mechanism seemed to involve oxidative stress and an anti-inflammatory effect on the endothelium of atheroprone vessels.