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

Regulation of atherogenesis by chemokines and chemokine receptors

Atherosclerosis is a chronic inflammatory and metabolic disorder affecting large- and medium-sized arteries, and the leading cause of mortality worldwide. The pathogenesis of atherosclerosis involves accumulation of lipids and leukocytes in the intima of blood vessel walls creating plaque. How leukocytes accumulate in plaque remains poorly understood; however, chemokines acting at specific G protein-coupled receptors appear to be important. Studies using knockout mice suggest that chemokine receptor signaling may either promote or inhibit atherogenesis, depending on the receptor. These proof of concept studies have spurred efforts to develop drugs targeting the chemokine system in atherosclerosis, and several have shown beneficial effects in animal models. This study will review key discoveries in basic and translational research in this area.

Therapeutic strategies to deplete macrophages in atherosclerotic plaques

Macrophages can be found in all stages of atherosclerosis and are major contributors of atherosclerotic plaque development, progression and destabilization. Continuous recruitment of monocytes drives this chronic inflammatory disease, which can be intervened by several strategies: reducing the inflammatory stimulus by lowering circulating lipids and promoting cholesterol efflux from plaque, direct and indirect targeting of adhesion molecules and chemokines involved in monocyte adhesion and transmigration and inducing macrophage death in atherosclerotic plaques in combination with anti-inflammatory drugs. This review discusses the outlined strategies to deplete macrophages from atherosclerotic plaques to promote plaque stabilization.

Restoration of alveolar type II cell function contributes to simvastatin-induced attenuation of lung ischemia-reperfusion injury

Alveolar type (AT) II cells transdifferentiate into ATI cells and as such represent a promising source for regenerating lung epithelium following lung injury. ATII cells are characterized by the presence of lamellar bodies (LBs), which store and secrete the surfactant protein-C (SP-C). Lung ischemia-reperfusion injury (LIRI) causes a distinct impairment of the ATII cell function, subsequently hindering lung repair by loss of ATI transdifferentiation. In this study, we provide new evidence that the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor simvastatin may restore the function of impaired ATII cells in vitro and in vivo. ATII cell lines, A549 (human) and MLE-12 (mouse), were subjected to hypoxia-reoxygenation (H/R) injury. Simvastatin pretreatment at low (5-20 µM), but not high (50-100 µM) doses markedly reduced apoptosis and increased proliferation and SP-C expression. In a rat lung ischemia-reperfusion (I/R) model, simvastatin treatment also increased ATII cell proliferation in vivo, as demonstrated by proliferating cell nuclear antigen/SP-C double staining. Transmission electron microscopy revealed that the number and volume density of LBs were significantly increased in the simvastatin-treated rat lungs. The protective effects of simvastatin were reversed in vitro by PI3-kinase (PI3K) inhibitors wortmannin and L-mevalonate, indicating that the PI3K/Akt and mevalonate pathways may be involved in simvastatin-induced ATII cell function restoration. These data demonstrate that an appropriate dose of simvastatin has a protective effect on LIRI in vitro and in vivo, due at least partially to restored ATII cell function via the HMG-CoA reductase pathway-dependent activation of PI3K/Akt signaling in a mevalonate pathway-dependent manner.

Reduced risk of poststroke pneumonia in thrombolyzed stroke patients with continued statin treatment

BACKGROUND

Pneumonia is a frequent complication after stroke with strong impact on clinical outcome. Statins have pleiotropic immunmodulatory properties and were recently shown to exert beneficial effects on the development and clinical course of pneumonia.

AIMS

We aimed to investigate whether statin use is associated with a reduced risk of poststroke pneumonia in acute ischemic stroke patients treated with tissue plasminogen activator within 4·5hours.

METHODS

Data was extracted from a local register including all consecutive stroke patients who received thrombolysis at our institution. Prior statin use was identified retrospectively from clinical records and had to be continued after hospital admission. Poststroke pneumonia was diagnosed according to standardized criteria of US Centers for Disease Control and Prevention. Mortality and functional outcome at three-months were further assessed.

RESULTS

Overall, 481 ischemic stroke patients were analyzed. Continued statin use was documented in 17% of the patients. Frequency of pneumonia was 11%. Patients with statin use were less likely to develop poststroke pneumonia (5% vs. 13%, P = 0·04). After multivariable adjustment for known risk factors for poststroke pneumonia (age, stroke severity, dysphagia, male sex and diabetes), statin treatment was negatively associated with pneumonia (OR 0·31; 95% CI 0·10-0·94). Occurrence of pneumonia independently predicted three-month mortality and functional outcome.

CONCLUSIONS

Use of statins in acute ischemic stroke patients who receive thrombolysis might reduce the risk of poststroke pneumonia. Further studies are warranted to validate this finding.

Statins and the risk of cancer after heart transplantation

BACKGROUND

Although newer immunosuppressive agents, such as mTOR (mammalian target of rapamycin) inhibitors, have lowered the occurrence of malignancies after transplantation, cancer is still a leading cause of death late after heart transplantation. Statins may have an impact on clinical outcomes beyond their lipid-lowering effects. The aim of the present study was to delineate whether statin therapy has an impact on cancer risk and total mortality after heart transplantation.

METHODS AND RESULTS

A total of 255 patients who underwent heart transplantation at the University Hospital Zurich between 1985 and 2007 and survived the first year were included in the present study. The primary outcome measure was the occurrence of any malignancy; the secondary end point was overall survival. During follow-up, a malignancy was diagnosed in 108 patients (42%). The cumulative incidence of tumors 8 years after transplantation was reduced in patients receiving a statin (34% versus 13%; 95% confidence interval, 0.25-0.43 versus 0.07-0.18; P<0.003). Statin use was associated with improved cancer-free and overall survival (both P<0.0001). A Cox regression model that analyzed the time to tumor formation with or without statin therapy, adjusted for age, male sex, type of cardiomyopathy, and immunosuppressive therapy (including switch to mTOR inhibitors or tacrolimus), demonstrated a superior survival in the statin group. Statins reduced the hazard of occurrence of any malignancy by 67% (hazard ratio, 0.33; 95% confidence interval, 0.21-0.51; P<0.0001).

CONCLUSIONS

Although it is not possible to adjust for all potential confounders because of the very long follow-up period, this registry suggests that statin use is associated with improved cancer-free and overall survival after cardiac transplantation. These data will need to be confirmed in a prospective trial.

Combined treatment of Aβ immunization with statin in a mouse model of Alzheimer's disease

We evaluated the therapeutic efficacy of combined treatment of Aβ-immunization with simvastatin in an Alzheimer mouse model at age 22 months. DNA prime-adenovirus boost immunization induced modest anti-Aβ titers and simvastatin increased the seropositive rate. Aβ-KLH was additionally administered to boost the titers. Irrespective of simvastatin, the immunization did not decrease cerebral Aβ deposits but increased soluble Aβ and tended to exacerbate amyloid angiopathy in the hippocampus. The immunization increased cerebral invasion of leukocytes and simvastatin counteracted the increase. Thus, modest anti-Aβ titers can increase soluble Aβ and simvastatin may reduce inflammation associated with vaccination in aged Alzheimer mouse models.

Statins and vein graft failure in coronary bypass surgery

Saphenous vein grafts used in coronary artery bypass graft surgery suffer from lower patency rates compared to left internal mammary artery. A number of clinical trials and observational studies have demonstrated a significant benefit of statin treatment on vein graft patency. Aside from their well-known lipid-lowering capacities, statins exert pleiotropic effects by direct inhibition of the mevalonate pathway in the wall of these grafts. This leads to reduced geranylgeranylation of small GTPases such as Rho and Rac. Through this LDL-independent mechanism, statins improve endothelial function and reduce vascular inflammation and oxidative stress, inhibiting also smooth muscle cell proliferation and migration. Although the existing evidence supports a beneficial effect of statins on vein grafts biology, more clinical trials focused on the effect of aggressive statin treatment on vein graft patency are required, in order to safely translate this strategy into clinical practice.

Anti-inflammatory and anti-thrombotic intervention strategies using atorvastatin, clopidogrel and knock-down of CD40L do not modify radiation-induced atherosclerosis in ApoE null mice

BACKGROUND AND PURPOSE

We previously showed that irradiating the carotid arteries of ApoE(-/-) mice accelerated the development of macrophage-rich, inflammatory and thrombotic atherosclerotic lesions. In this study we investigated the potential of anti-inflammatory (atorvastatin, CD40L knockout) and anti-thrombotic (clopidogrel) intervention strategies to inhibit radiation-induced atherosclerosis.

MATERIAL AND METHODS

ApoE(-/-) mice were given 0 or 14 Gy to the neck and the carotid arteries were harvested at 4 or 28 weeks after irradiation. Atorvastatin (15 mg/kg/day) or clopidogrel (20 mg/kg/day) was given in the chow; control groups received regular chow. Clopidogrel inhibited platelet aggregation by 50%. CD40L(-/-)/ApoE(-/-) and ApoE(-/-) littermates were also given 0 or 14 Gy to the neck and the carotid arteries were harvested after 30 weeks.

RESULTS

Clopidogrel decreased MCP-1 expression in the carotid artery at 4 weeks after irradiation. Expression of VCAM-1, ICAM-1, thrombomodulin, tissue factor and eNOS was unchanged in atorvastatin and clopidogrel-treated mice. Neither drug inhibited either age-related or radiation-induced atherosclerosis. Furthermore, loss of the inflammatory mediator CD40L did not influence the development of age-related and radiation-induced atherosclerosis.

CONCLUSIONS

The effects of radiation-induced atherosclerosis could not be circumvented by these specific anti-inflammatory and anti-coagulant therapies. This suggests that more effective drug combinations may be required to overcome the radiation stimulus, or that other underlying mechanistic pathways are involved compared to age-related atherosclerosis.

CCR1 as a target for multiple myeloma

INTRODUCTION

By directing cell trafficking, differentiation and growth, chemokines modulate the immune response and are involved in the pathogenesis of autoimmune diseases and cancers, including multiple myeloma (MM). MM, the second most common hematological malignancy in the US, is characterized by disordered plasma cell growth within the bone marrow microenvironment. CCL3 and its receptors, CCR1 in particular, play a central role in the pathogenesis of MM and MM-induced osteolytic bone disease.

AREAS COVERED

This review describes the functional role of CCR1 in MM and the preclinical results observed with CCR1 antagonists. CCL3 and CCR1 stimulate tumor growth, both directly and indirectly, via upregulation of cell adhesion and cytokine secretion. In addition, they modulate the osteoclast/osteoblast balance, by inducing osteoclast differentiation and inhibiting osteoblast function. Targeting either ligand or receptor reverses these effects, leading to in vivo tumor burden control and prevention of osteolysis, as confirmed in both murine and humanized mouse models.

EXPERT OPINION

These promising data set the stage for clinical trials to assess the effects of CCR1 inhibitors in MM. The success of these studies depends on the development of novel antagonists with improved chemical/physical properties and careful selection of the patient population who may benefit the most from these agents.

Preoperative Statin use is not Associated with a Reduced Risk of Atrial Fibrillation After Cardiac Surgery

Introduction: Postoperative atrial fibrillation (POAF) is prevalent after cardiac surgery and associated with significant morbidity and costs. Statins are commonly used in this population and may be a preventative strategy for PAOF. We wished to examine the effect of preoperative statin use on the risk of POAF after cardiac surgery. Methods: A retrospective, observational study was conducted using data from 489 adult patients who underwent cardiac surgery at a single institution. Univariate analyses and unconditional logistic regression were used to determine the impact of preoperative statin use on the probability of developing POAF, while controlling for the baseline risk of POAF and the use of amiodarone prophylaxis (AMP). A baseline risk index was calculated for each patient using a previously validated model. Patients with chronic atrial fibrillation or missing data were excluded. Results: Mean patient age was 63 (SD=13) years, 73% were male, 68% underwent isolated coronary artery bypass grafting, 16% underwent isolated valve surgery, with 13% underwent combined CABG and valve surgeries, and 3% underwent other forms of cardiac surgery. POAF occurred in 27% of patients receiving statins and 24% of those not receiving statins (p=0.3792). After controlling for baseline risk of POAF and the use of AMP, we found that preoperative statins were not associated with reductions in POAF (OR=1.19, 95%CI=0.782-1.822, p=0.4118). Conclusions: Multiple factors impact the development of POAF after cardiac surgery including patient demographics, comorbidities, surgical type, and concomitant medications. In this study, after adjustment for these factors the preoperative use of statins did not significantly influence the development of POAF.

Role of endothelial chemokines and their receptors during inflammation

Chemokines are a large group of small cytokines known for their chemotactic ability to regulate the recruitment of leukocytes to sites of inflammation. This occurs through the binding of chemokines to their receptors located on the leukocyte that results in cellular changes such as actin rearrangement and cell shape, which allow for the migration of the leukocyte. In addition to regulating leukocyte function, it is now becoming apparent that other nonhematopoetic cells, such as smooth muscle cells and endothelial cells, can also be regulated by chemokines. Studies within the past 10 years has demonstrated the presence of various chemokine receptors on endothelial cells as well as the ability of chemokines to activate these receptors resulting in various cellular responses including migration, proliferation, and cellular activation. The purpose of this review is to highlight the research that has been done to date demonstrating the important role for chemokines in regulating endothelial function during various inflammatory conditions associated with angiogenesis, homeostasis, and leukocyte transmigration. This review will focus specifically on the role of the endothelium in mediating chemokine effects associated with wound healing, atherosclerosis, and autoimmune diseases, conditions where leukocyte recruitment and angiogenesis play a major role. Recent progress in the development and implementation of therapeutics agents against these small molecules, or their receptors, will also be addressed.

Pleiotropic effects of statins. - Basic research and clinical perspectives -

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are widely used to lower serum cholesterol levels in the primary and secondary prevention of cardiovascular disease. Recent experimental and clinical evidence suggests that the beneficial effects of statins may extend beyond their cholesterol-lowering effects, to include so-called pleiotropic effects. These cholesterol-independent effects include improving endothelial function, attenuating vascular and myocardial remodeling, inhibiting vascular inflammation and oxidation, and stabilizing atherosclerotic plaques. The mechanism underlying some of these pleiotropic effects is the inhibition of isoprenoid synthesis by statins, which leads to the inhibition of intracellular signaling molecules Rho, Rac and Cdc42. In particular, inhibition of Rho and one of its downstream targets, Rho kinase, may be a predominant mechanism contributing to the pleiotropic effects of statins. The aim of the present review is to provide an update on the non-cholesterol-dependent statin effects in the cardiovascular system and highlight some of the recent findings from bench to bedside to support the concept of statin pleiotropy.

Thioredoxin 1 downregulates MCP-1 secretion and expression in human endothelial cells by suppressing nuclear translocation of activator protein 1 and redox factor-1

To know whether thioredoxin 1 (Trx1) works for an antioxidant defense mechanism in atherosclerosis, the effect of Trx1 on the release of monocyte chemoattractant protein-1 (MCP-1), a potent chemoattractant for recruitment and accumulation of monocytes/macrophages in the intima of artery vessel, was investigated in human endothelial-like EA.hy 926 cells. It was found that overexpression of Trx1 suppressed, whereas knockdown of endogenous Trx1 enhanced, oxidized low-density lipoprotein (oxLDL)-stimulated MCP-1 release and expression in the cells. It was also observed that overexpression of Trx1 suppressed, whereas depletion of endogenous Trx1 greatly promoted, nuclear translocation of c-Jun and the redox factor-1 (Ref-1). Electrophoretic mobility shift assay showed significantly reduced DNA-binding activity of activator protein-1 (AP-1) in Trx1-overexpressing cells but apparently enhanced DNA binding activity of AP-1 in Trx1-knockdown cells, indicating that nuclear Ref-1 rather than Trx1 itself finally dominates the regulation of AP-1 activity, although Trx1 is considered to upregulate AP-1 activity. It was also observed that Trx1 depressed intracellular generation of reactive oxygen species (ROS). Diphenyleneiodonium (DPI), the inhibitor of NADPH oxidase, suppressed MCP-1 secretion, whereas transient expression of Nox1 enhanced transcription of MCP-1 in endothelial cells. Assays with AP-1 and MCP-1 luciferase reporters further demonstrated that transient expression of Trx1 significantly depressed the transcriptional activity of c-Jun/c-Fos and consequent MCP-1 transcription. This study suggests that Trx1 inherently suppresses MCP-1 expression in vascular endothelium and may prevent atherosclerosis by depressing MCP-1 release. Besides the suppression of intracellular ROS generation, the inhibition of nuclear translocation of AP-1 and Ref-1 are mainly responsible for the downregulation of MCP-1 by Trx1.

GGTI-2133, an inhibitor of geranylgeranyltransferase, inhibits infiltration of inflammatory cells into airways in mouse experimental asthma

Statins have been proposed as a novel treatment of respiratory diseases including asthma. Although the mechanism of anti-inflammatory effect of statins is still unclear, an inhibition of protein prenylation by depleting the downstream metabolites of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase might be involved. To test the hypothesis, the effects of GGTI-2133, a direct inhibitor of geran ylgeranyltransferase (GGTase), on antigen-induced airway inflammation were investigated in a murine model of allergic bronchial asthma. Mice were sensitized and repeatedly challenged with ovalbumin antigen (OA). Animals were also treated with GGTI-2133 (5 mg/kg/day, i.p.) once a day before and during the antigen inhalation period. Repeated antigen inhalation caused an infiltration of inflammatory cells, especially eosinophils, into airways. Significant increases in interleukin (IL)-4, IL-13, eotaxin, thymus and activation-regulated chemokine (TARC) and leukotriene B4 (LTB4) in bronchoalveolar lavage fluids and total and OA-specific IgE in sera were also found in the antigen-exposed animals. The systemic treatments with GGTI-2133 inhibited the antigen-induced eosinophil infiltration into airways almost completely. However, interestingly, the GGTI-2133 treatment did not affect the levels of these chemotactic factors and IgE. These findings suggest that selective inhibition of GGTase is effective for eosinophilic airway inflammation such as asthma.

Statins suppress interleukin-6-induced monocyte chemo-attractant protein-1 by inhibiting Janus kinase/signal transducers and activators of transcription pathways in human vascular endothelial cells

BACKGROUND AND PURPOSE

The mechanisms of anti-inflammatory actions of statins, 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase inhibitors, remain unclear. We investigated the effects of statins on interleukin (IL)-6-induced monocyte chemo-attractant protein (MCP)-1 expression and monocyte chemotaxis.

EXPERIMENTAL APPROACH

Cultures of human aortic endothelial cells (HAECs) were stimulated with IL-6 in the absence and presence of statins. Gene expression and protein secretion of MCP-1, phosphorylation of Janus kinase (JAK) and the signal transducers and activators of transcription (STAT) pathway, and human monocyte migration were examined.

KEY RESULTS

IL-6 plus its soluble receptor sIL-6R (IL-6/sIL-6R) promoted THP-1 monocyte migration, and increased gene expression and protein secretion of MCP-1, more than IL-6 alone or sIL-6R alone. Various statins inhibited IL-6/sIL-6R-promoted monocyte migration and MCP-1 expression in HAECs. Co-incubation of mevalonate and geranylgeranyl pyrophosphate, but not farnesyl pyrophosphate, reversed the inhibitory effects of statins on MCP-1 expression. Geranylgeranyl transferase inhibitor, but not farnesyl transferase inhibitor, suppressed IL-6/sIL-6R-stimulated MCP-1 expression. IL-6/sIL-6R rapidly phosphorylated JAK1, JAK2, TYK2, STAT1 and STAT3, which were inhibited by statins. Transfection of STAT3 small interfering RNA (siRNA), but not STAT1 siRNA, attenuated the ability of IL-6/sIL-6R to enhance THP-1 monocyte migration. In addition, statins blocked IL-6/sIL-6R-induced translocation of STAT3 to the nucleus.

CONCLUSIONS AND IMPLICATIONS

Statins suppressed IL-6/sIL-6R-induced monocyte chemotaxis and MCP-1 expression in HAECs by inhibiting JAK/STAT signalling cascades, explaining why statins have anti-inflammatory properties beyond cholesterol reduction.

Does statin use improve pneumonia outcomes?

Despite medical advances, pneumonia remains a leading cause of morbidity and mortality among patients in developed countries. It is therefore not surprising that much research has been devoted to improving outcomes associated with this condition. Traditionally thought of as lipid-lowering agents, the 3-hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitors (hereafter referred to as statins) have "pleiotropic" effects of clinical relevance. Several studies have reported an association between statin use and improved health outcomes, including those associated with pneumonia. While many of these are limited by their retrospective or observational methodology, the finding that statin use may improve pneumonia outcomes is tantalizing and worthy of further exploration. Our review of the literature found several potential mechanisms by which statins could influence the course of bacterial pneumonia. For instance, statins directly attenuate inflammation and inflammatory markers, are antioxidative and immunomodulatory, and exert in vitro antibacterial effects on microbial pathogens. On the other hand, statin use is also thought to be a surrogate marker for better health and may simply be a confounding variable when it comes to pneumonia. This article explores some of the potential mechanisms by which statin therapy may impact the course of pneumonia. In addition, we review the clinical studies both supporting and arguing against such an effect.

The role of chemokines in recruitment of immune cells to the artery wall and adipose tissue

The role of the immune system is to recognize pathogens, tumor cells or dead cells and to react with a very specific and localized response. By taking advantage of a highly sophisticated system of chemokines and chemokine receptors, leukocytes such as neutrophils, macrophages, and T-lymphocytes are targeted to the precise location of inflammation. While this is a beneficial process for acute infection and inflammation, recruitment of immune cells to sites of chronic inflammation can be detrimental. It is becoming clear that these inflammatory cells play a significant role in the initiation and progression of metabolic disorders such as atherosclerosis and insulin resistance by infiltrating the artery wall and adipose tissue (AT), respectively. Data from human studies indicate that elevated plasma levels of chemokines are correlated with these metabolic diseases. Recruitment of macrophages to the artery wall is well known to be one of the first steps in early atherosclerotic lesion formation. Likewise, recruitment of macrophages to AT is thought to contribute to insulin resistance associated with obesity. Based on this knowledge, much recent work in these areas has focused on the role of chemokines in attracting immune cells (monocytes/macrophages in particular) to these 2 sites. Thus, understanding the potential for chemokines to contribute to metabolic disease can help direct studies of chemokines as therapeutic targets. In this article, we will review current literature regarding the role of chemokines in atherosclerosis and obesity-related insulin resistance. We will focus on novel work showing that chemokine secretion from endothelial cells, platelets, and adipocytes can contribute to immune cell recruitment, with a diagram showing the time course of chemokine expression and leukocyte recruitment to AT. We will also highlight a few of the less-commonly known chemokine-chemokine receptor pairs. Finally, we will discuss the potential for chemokines as therapeutic targets for treatment of atherosclerosis and insulin resistance.

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

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

Simvastatin inhibits airway hyperreactivity: implications for the mevalonate pathway and beyond

RATIONALE

Statin use has been linked to improved lung health in asthma and chronic obstructive pulmonary disease. We hypothesize that statins inhibit allergic airway inflammation and reduce airway hyperreactivity via a mevalonate-dependent mechanism.

OBJECTIVES

To determine whether simvastatin attenuates airway inflammation and improves lung physiology by mevalonate pathway inhibition.

METHODS

BALB/c mice were sensitized to ovalbumin over 4 weeks and exposed to 1% ovalbumin aerosol over 2 weeks. Simvastatin (40 mg/kg) or simvastatin plus mevalonate (20 mg/kg) was injected intraperitoneally before each ovalbumin exposure.

MEASUREMENTS AND MAIN RESULTS

Simvastatin reduced total lung lavage leukocytes, eosinophils, and macrophages (P < 0.05) in the ovalbumin-exposed mice. Cotreatment with mevalonate, in addition to simvastatin, reversed the antiinflammatory effects seen with simvastatin alone (P < 0.05). Lung lavage IL-4, IL-13, and tumor necrosis factor-alpha levels were all reduced by treatment with simvastatin (P < 0.05). Simvastatin treatment before methacholine bronchial challenge increased lung compliance and reduced airway hyperreactivity (P = 0.0001).

CONCLUSIONS

Simvastatin attenuates allergic airway inflammation, inhibits key helper T cell type 1 and 2 chemokines, and improves lung physiology in a mouse model of asthma. The mevalonate pathway appears to modulate allergic airway inflammation, while the beneficial effects of simvastatin on lung compliance and airway hyperreactivity may be independent of the mevalonate pathway. Simvastatin and similar agents that modulate the mevalonate pathway may prove to be treatments for inflammatory airway diseases, such as asthma.

Confronting the next influenza pandemic with anti-inflammatory and immunomodulatory agents: why they are needed and how they might work

Despite the best efforts of influenza scientists, companies and health officials to prepare for the next pandemic, most of the world's people will not have access to affordable supplies of vaccines and antiviral agents. They will have to rely on 19th century public health 'technologies' to see them through. In the 21st century, science ought to be able to provide something better. Influenza scientists study the molecular characteristics of influenza viruses and their signaling effects in cell culture and animal models of infection. While these studies have been enormously informative, they have been unable to explain the system-wide effects of influenza on the host, the increased mortality of younger adults in the 1918 influenza pandemic and the much lower mortality rates in children who were more commonly infected with the 1918 virus. Experiments by non-influenza scientists have defined common cell signaling pathways for acute lung injury caused by different agents, including inactivated H5N1 influenza virus. These pathways include several molecular targets that are up-regulated in acute lung injury and down-regulated by anti-inflammatory and immunomodulatory agents, including statins, fibrates, and glitazones. These agents also help reverse the mitochondrial dysfunction that accompanies multi-organ failure, something often seen in fatal Influenza. Observational studies suggest that statins are beneficial in treating patients with pneumonia (there are no such studies for fibrates and glitazones). Other studies suggest that these agents might be able to 'roll back' the self-damaging host response of young adults to the less damaging response of children and thus save lives. Research is urgently needed to determine whether these and other agents that modify the host response might be useful in managing H5N1 influenza and the next pandemic.

Update on statin-mediated anti-inflammatory activities in atherosclerosis

Anti-inflammatory activities of statins in atherosclerosis have been well documented by both basic research and clinical studies. Statins have been introduced in the 1980s as 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors to block cholesterol synthesis and lower cholesterol serum levels. In the last three decades, statins have been shown to possess several anti-inflammatory and antioxidant activities resulting in the beneficial reduction of atherosclerotic processes and cardiovascular risk in both humans and animal models. Inflammatory intracellular pathways involving kinase phosphorylation and protein prenylation are modulated by statins. The same intracellular mechanisms might also cause statin-induced myotoxicity. In the present review, we will update evidence on statin-mediated regulation of inflammatory pathways in atherogenesis.

Shear stress preconditioning modulates endothelial susceptibility to circulating TNF-alpha and monocytic cell recruitment in a simplified model of arterial bifurcations

OBJECTIVE

Atherosclerotic plaque formation results from a combination of local shear stress patterns and inflammatory processes. This study investigated the endothelial response to shear stress in combination with the inflammatory cytokine TNF-alpha in a simplified model of arterial bifurcation.

METHODS

Human umbilical vein endothelial cells (ECs) were exposed to laminar or non-uniform shear stress in bifurcating flow-through slides, followed by stimulation with TNF-alpha. To study cell adhesion, ECs were perfused with medium containing THP-1 monocytic cells. Endothelial protein expression was determined by immunofluorescence.

RESULTS

Adhesion of monocytic cells to unstimulated ECs was nearly undetectable under laminar shear stress and was slightly increased under non-uniform shear stress. Exposure of ECs to non-uniform shear stress in combination with TNF-alpha induced a 12-fold increase in monocytic cell recruitment and a significant induction of endothelial E-selectin and VCAM-1 expression. Both these effects were prevented in ECs exposed to laminar shear stress. The significant differences in TNF-alpha-induced monocytic cell recruitment and adhesion molecule expression between laminar and non-uniform shear stress regions were abolished in the absence of shear stress preconditioning. Simvastatin (1 micromol/L) suppressed the non-uniform shear stress- and TNF-alpha-induced increase in monocytic cell adhesion by about 30% via inhibition of VCAM-1 expression. Resveratrol, the active component of red wine, inhibited the expression of both VCAM-1 and E-selectin, and reduced monocytic cell recruitment by 50% at 20 micromol/L.

CONCLUSIONS

Non-uniform shear stress induces endothelial susceptibility to circulating TNF-alpha and adhesion of monocytic cells. Interference with this process may inhibit inflammatory response in atherosclerosis-prone regions.

Potential immunologic effects of statins in cancer following transplantation

3-hydroxy-3-methyglutaryl CoA reductase inhibitors (statins) are frequently used following organ transplantation and have well reported pleiotropic effects, including immunomodulation, which may be of benefit in preventing graft rejection. However, the immunomodulatory effects of statins on cell transformation and malignancy, combined with the immunologic processes and administration of immunosuppression are almost completely unknown. The administration of immunosuppression is well recognised as the main cause of cancer following transplantation, so the addition of an immunomodulatory agent should be associated with an increased incidence of cancer, as immune surveillance and response may be suppressed, allowing cellular transformation and proliferation combined with lack of recognition to occur. This hypothetical review attempts to delineate the mode of action of statins in terms of pro/anti-carcinogenic mechanisms, while considering graft rejection and the presence of immunosuppression.

Chemokine–chemokine receptors in cancer immunotherapy

A surge in interest in the chemokine–chemokine receptor network is probably related to the expanding roles that chemokines have now been identified to play in human biology, particularly immunity. Specific tissue microenvironments express distinct chemokines and both hematopoietic and nonhematopoietic cells have receptor expression profiles that permit the coordinated trafficking and organization of cells within these specific tissues. Since the chemokine network plays critical roles in both the function of the immune system and the progression of cancer, it is an attractive target for therapeutic manipulation. This review will focus on chemokine and chemokine receptor network-related therapeutic interventions that utilize host–tumor interactions particularly involving the immune system.

Pravastatin attenuates interferon-gamma action via modulation of STAT1 to prevent aortic atherosclerosis in apolipoprotein E-knockout mice

1. The beneficial effects of pravastatin, beyond that of lowering cholesterol in atherosclerosis, include reducing the action of interferon (IFN)-gamma. Interferon-gamma activates the signal transducer and activator of transcription 1 (STAT1), but it is unclear whether the inhibitory effect of pravastatin in atherosclerosis is via modulation of the IFN-gamma/STAT1 pathway. Thus, the aim of the present study was to determine whether the action of pravastatin in preventing aortic atherosclerosis by attenuation of IFN-gamma action is dependent on STAT1. 2. Male apolipoprotein E-knockout (apoE(-/-)) mice were fed a diet containing 1.25% cholesterol (w/w). Mice were divided into two groups, one of which was supplemented with pravastatin (80 mg/kg per day). Male C57BL/6J mice were fed a normal diet and served as the control group (n = 12 per group). 3. Atherosclerotic lesions in the aortic root were assessed by staining sections haematoxylin and eosin. Serum concentrations of IFN-gamma and IFN-gamma mRNA expression in the thoracoabdominal aorta were determined by ELISA and real-time quantitative polymerase chain reaction methods, respectively. Expression of phosphorylated STAT1 (pSTAT1), interferon regulating factor (IRF)-1 and suppressors of cytokine signalling 1 (SOCS1) was determined in the thoracoabdominal aorta using Western blot analysis. 4. After 8 weeks, pravastatin treatment significantly prevented the formation of atherosclerotic lesions (P < 0.05) and reduced serum IFN-gamma concentrations (P < 0.05) and levels of IFN-gamma mRNA within the aorta (P < 0.01). Pravastatin significantly decreased the expressions of pSTAT1 and IRF-1 within the aorta and significantly increased expression of SOCS1. 5. These results suggest that the actions of pravastatin in attenuating the action of IFN-gamma and subsequently preventing aortic atherosclerosis may depend, at least in part, on modulation of STAT1 activity. This providing us with a new therapeutic approach and a clearer insight into the clinical benefits of pravastatin.

Disparate effects of simvastatin on angiogenesis during hypoxia and inflammation

AIMS

Studies have shown that some of statin's pleiotropic effects were achieved by either promotion or inhibition of angiogenesis, depending on the underlying disease. This study tested the hypothesis that the angiogenic potential of simvastatin is related to the microenvironmental conditions.

MAIN METHODS

Human umbilical vein endothelial cells (HUVEC) were studied after exposure to hypoxia or the inflammatory factors tumor necrosis factor (TNF)-alpha, with or without co-incubation with simvastatin (1 micromol/L) and mevalonate. HUVEC angiogenesis was evaluated by tube formation, migration, and proliferation assays. Hypoxia inducible factor (HIF)-1alpha, vascular endothelial growth factor (VEGF), Akt, endothelium nitric oxide synthase (e-NOS), and oxidative stress were evaluated.

KEY FINDINGS

HUVEC angiogenesis increased during hypoxia (tube length 14.7+/-0.5 vs. 7.8+/-0.6 mm, p<0.05) and further enhanced by simvastatin (19.3+/-1.1 mm, p<0.05 vs. hypoxia alone), which downregulated the expression of the HIF-1 inhibitor PHD2 and upregulated HIF-1alpha, VEGF, and Akt, without changing oxidative stress or eNOS. Incubation with TNF-alpha promoted HUVEC angiogenesis (7.4+/-0.2 vs. 6.5+/-0.2 mm, p<0.05) with increased oxidative stress. However, simvastatin inhibited this promotion (2.5+/-0.3 mm, p<0.001 vs. TNF-alpha alone) by decreasing oxidative stress, VEGF, Akt, and eNOS.

SIGNIFICANCE

We conclude that at the same dosage, simvastatin can either promote or inhibit angiogenesis, possibly by activating upstream regulators of HIF-1alpha in hypoxia, but conversely interfering with angiogenic signaling downstream to inflammation. These opposing angiogenic effects should be considered in the therapeutic strategies with statins.

Use of atorvastatin as an anti-inflammatory treatment in Crohn's disease

BACKGROUND AND PURPOSE

Experimental and clinical investigations have revealed that statins can downregulate both acute and chronic inflammatory processes. Whether statins express anti-inflammatory activities in the treatment of Crohn's disease is unknown.

EXPERIMENTAL APPROACH

Ten patients were given 80 mg atorvastatin once daily for 13 weeks and then followed up for 8 weeks after the treatment. The anti-inflammatory effects of statin were assessed by measuring levels of plasma C-reactive protein (CRP), soluble (s) CD14, tumour necrosis factor (TNF)-alpha, sTNFRI and II, CCL2 and 8 and the mucosal inflammation by faecal calprotectin. Circulating monocytes were subgrouped and their chemokine receptor expression of CCR2 and CX(3)CR1 were analysed.

KEY RESULTS

In 8 of 10 patients, atorvastatin treatment reduced CRP (P=0.008) and sTNFRII (P=0.064). A slight decrease in plasma levels of sCD14, TNF-alpha and sTNFRI was observed in 7/10 patients and faecal calprotectin was reduced in 8/10 patients. We also observed that the treatment diminished expression of CCR2 and CX(3)CR1 on monocyte populations (P=0.014). At the follow-up visit, 8 weeks after the atorvastatin treatment was terminated, CRP levels had returned to those seen before the treatment.

CONCLUSIONS AND IMPLICATIONS

Our findings imply that atorvastatin therapy reduces inflammation in patients with Crohn's disease and, therefore, encourage further investigations of statin-mediated protective effects in inflammatory bowel diseases.

C-reactive protein: the harbinger of cardiovascular diseases

Coronary heart disease remains the major cause of mortality and morbidity in the United States and other western countries despite major advances in its treatment. During the last decades, many markers of coronary artery disease have been found which help predict future risk of cardiovascular events. High-sensitivity C-reactive protein has been studied extensively and was seen to be associated with a higher risk of cardiovascular events in patients with acute coronary syndromes and/or peripheral artery disease. Discussed in this review is the latest literature about this marker and its association with cardiovascular disease, as well as the latest therapeutic options available.

In vivo transmigrated monocytes from patients with stable coronary artery disease have a reduced expression of CD11b

Coronary artery disease (CAD) is characterized by infiltration of monocyte derived cells in the intima of the vessel wall. We hypothesized that accumulation of these cells is caused partly by an altered monocyte transmigration process in CAD. To gain insight into this issue we applied the skin blister method that allows collection of in vivo transmigrated cells at sites of local inflammation. Nineteen patients with stable CAD and 19 matched controls were enrolled. Markers of inflammation and gradients of chemokines, as well as adhesion molecule expression and up-regulation capacity, were studied. The expression of inflammatory markers, such as C-reactive protein, interleukin (IL)-6, tumour necrosis factor-alpha and IL-10, was similar in patients and controls, indicating that patients were in a stable phase of the disease. Expression of adhesion molecules, CD11b and very late activation antigen-4, on peripheral monocytes did not differ between patients and controls. However, following in vivo transmigration, monocytes in patients with CAD had a significantly reduced expression and mobilization of CD11b. The effect on CD11b could not be reproduced by in vitro stimulation with blister fluid, representing a local inflammatory milieu, or in an in vitro system of transmigration. These findings point towards differences in monocyte CD11b expression and availability at an inflammatory site between patients with CAD and healthy controls.

Inhibitory effect of simvastatin on the TNF-alpha- and angiotensin II-induced monocyte adhesion to endothelial cells is mediated through the suppression of geranylgeranyl isoprenoid-dependent ROS generation

Vascular endothelial cell activation by cytokines and other pro-inflammatory mediators is an initial event in atherosclerosis and in other vascular diseases. Simvastatin, a HMG-CoA reductase inhibitor, suppressed both tumor necrosis factor (TNF)-alpha- and angiotensin (Ang) II-induced monocyte adhesion to endothelial cells (an initial step in vascular inflammation) and reactive oxygen species (ROS) production. Diphenyleneiodonium and apocynin, both NADPH oxidase inhibitors, also suppressed TNF-alpha-induced ROS and monocyte-endothelial cell adhesion, demonstrating that TNF-alpha-induced monocyte adhesion is mediated through ROS produced by NADPH oxidase activation. Furthermore, exogenously applied mevalonate or geranylgeranylpyrophosphate in combination with simvastatin completely prevented the inhibitory effects of simvastatin on ROS generation and monocyte-endothelial cell adhesion by TNFalpha and Ang II. These results suggest that monocyte adhesion to endothelial cells induced by TNF-alpha or Ang II is mediated via the geranylgeranyl isoprenoid-dependent generation of ROS, and that this is inhibited by simvastatin.

Common CCR5-del32 frameshift mutation associated with serum levels of inflammatory markers and cardiovascular disease risk in the Bruneck population

BACKGROUND AND PURPOSE

Atherosclerosis is a progressive inflammatory disease and can develop in large arteries such as carotid and femoral arteries or medium-sized muscular arteries of the heart. Previous predominantly experimental studies suggested an important role of chemokines in the development of atherosclerosis. The main aim of this study was to examine potential effect of the CCR5-del32 mutation on systemic inflammation, intima-media thickness in carotid and femoral arteries, and on the indices of cardiovascular disease.

METHODS

In the present study, we have examined the association of a common functional 32-bp frameshift deletion mutation in a chemokine receptor (CCR5) in relation to inflammation and atherosclerosis. CCR5 is a G protein-coupled receptor involved in inflammatory response and regulation of leukocytes activation and migration. Genetic screening of this mutation was carried out on a well-known and previously described cohort of Bruneck (n=826) using polymerase chain reaction.

RESULTS

Screening was successful in 810 subjects of whom 7 were homozygous, 102 were heterozygous, and 701 were normal. The mutation was associated with significantly lower levels of C-reactive protein in a dose-dependent manner. Moreover, CCR5-del32 was associated with a significantly lower carotid intima-media thickness in the common carotid artery (del32/del32, 837+/-8 microm; wt/del32, 909+/-21 microm; wt/wt, 958+/-8 microm; P=0.007 after multivariable adjustment). Furthermore, incident cardiovascular disease (1995 to 2005) was markedly reduced in del32 homozygotes and heterozygotes subjects compared with wild-type homozygotes (del32/del32=0%, wt/del32=7.8%, wt/wt=14.8%, P=0.020). Findings equally applied to coronary artery and cerebrovascular disease.

CONCLUSIONS

The chemokine receptor CCR5-del32 frameshift mutation is associated with low levels of C-reactive protein, decreased intima-media thickness, and cardiovascular disease risk. These findings are consistent with the hypothesis that the chemokine receptor CCR5 is involved in the mediation of low-grade systemic inflammation and may play a role in human atherosclerosis and cardiovascular disease.

Reversal of elastase-induced pulmonary emphysema and promotion of alveolar epithelial cell proliferation by simvastatin in mice

Besides lowering cholesterol, statins exert multiple effects, such as anti-inflammatory activity and improvement of endothelial cell function. We examined whether simvastatin (SS) protects against the development of elastase-induced pulmonary emphysema in mice by using mean linear intercepts of alveoli (Lm) as a morphometric parameter of emphysema. After injection of intratracheal elastase on day 0, C57BL/6 mice were treated daily with SS (SS+ group) or PBS (SS- group) for 2 wk. A 21% decrease in Lm on day 7 was observed in the SS+ group vs. the SS- group. Anti-inflammatory effects of SS were observed as a decrease in percentage of neutrophils up to day 3, and in hydroxyproline concentration on day 3, in bronchoalveolar lavage fluid (BALF). SS also increased the number of proliferating cell nuclear antigen (PCNA)-positive alveolar epithelial cells between days 3 and 14. To confirm the role of statins in promoting proliferation of alveolar cells, mice were treated with SS (SS+) vs. PBS (SS-) for 12 days, starting 3 wk after elastase administration. After SS treatment, Lm decreased by 52% and PCNA-positive alveolar epithelial cells increased compared with the SS- group. Concentrations of vascular endothelial growth factor in BALF and endothelial nitric oxide synthase protein expression in pulmonary vessels tended to be higher in the SS+ group vs. the SS- group in this protocol. In conclusion, SS inhibited the development of elastase-induced pulmonary emphysema in mice. This therapeutic effect was due not only to anti-inflammation but also to the promotion of alveolar epithelial cell regeneration, partly mediated by restoring endothelial cell functions.

Simvastatin and indomethacin have similar anti-inflammatory activity in a rat model of acute local inflammation

Statins, such as simvastatin, lower circulating cholesterol levels and are widely prescribed for the treatment of hypercholesterolaemia. Several studies have shown unexpected effects of statins on inflammation. We studied the anti-inflammatory effect of simvastatin using a standard model of an acute local inflammation, the carrageenan-induced footpad oedema. Experimental groups (n = 6-8) were given simvastatin in a dose range 5-30 mg/kg, indomethacin 1-8 mg/kg and methylcellulose (control) per os. Footpad volume was measured with a plethysmograph and compared with the pre-injection volume of the same paw. Swelling (in microlitres) was then calculated, and in drug-treated animals, per cent inhibition was derived through comparison with the control group. Histopathological examination of the skin biopsies was performed to examine severity of paw skin lesions and to confirm the simvastatin-induced inhibition of acute inflammation. Both simvastatin and indomethacin administered orally, 1 hr before carrageenan injection, significantly reduced the extent of footpad oedema. Indomethacin dose-dependently blocked the swelling; the maximal effect was obtained with 8 mg/kg by 48.3% (P < 0.05). Simvastatin produced a comparable anti-inflammatory activity at a dose of 5 mg/kg (32%), while 10 and 30 mg/kg caused a 47.6% and 51.7% reduction, respectively, with the maximal effect observed at 20 mg/kg by 57.2% (P < 0.05). The comparison of the ED(50) of these agents on molar basis showed equipotent anti-inflammatory activity. Histopathological examination of the footpad skin biopsies revealed that simvastatin, dose-dependently and comparablly to indomethacin, reduced polymorphonuclear leucocyte infiltration. These data support the hypothesis that simvastatin has an acute anti-inflammatory activity.

Inhibition of rho family functions by lovastatin promotes myelin repair in ameliorating experimental autoimmune encephalomyelitis

Impaired remyelination is critical to neuroinflammation in multiple sclerosis (MS), which causes chronic and relapsing neurological impairments. Recent studies revealed that immunomodulatory activity of statins in an experimental autoimmune encephalomyelitis (EAE) model of MS are via depletion of isoprenoids (farnesyl-pyrophosphate and geranylgeranyl-pyrophosphate) rather than cholesterol in immune cells. In addition, we previously documented that lovastatin impedes demyelination and promotes myelin repair in treated EAE animals. To this end, we revealed the underlying mechanism of lovastatin-induced myelin repair in EAE using in vitro and in vivo approaches. Survival, proliferation (chondroitin sulfate proteoglycan-NG2(+) and late oligodendrocyte progenitor marker(+)), and terminal-differentiation (myelin basic protein(+)) of OPs was significantly increased in association with induction of a promyelinating milieu by lovastatin in mixed glial cultures stimulated with proinflammatory cytokines. Lovastatin-induced effects were reversed by cotreatment with mevalonolactone or geranylgeranyl-pyrophosphate, but not by farnesyl-pyrophosphate or cholesterol, suggesting that depletion of geranygeranyl-pyrophosphate is more critical than farnesyl-pyrophosphate in glial cells. These effects of lovastatin were mimicked by inhibitors of geranylgeranyl-transferase (geranylgeranyl transferase inhibitor-298) and downstream effectors {i.e., Rho-family functions (C3-exoenzyme) and Rho kinase [Y27632 (N-(4-pyridyl)-4-(1-aminoethyl)cyclohexanecarboxamide dihydrochloride)]} but not by an inhibitor of farnesyl-transferase (farnesyl transferase inhibitor-277). Moreover, activities of Rho/Ras family GTPases were reduced by lovastatin in glial cells. Corresponding with these findings, EAE animals exhibiting demyelination (on peak clinical day; clinical scores >/=3.0) when treated with lovastatin and aforementioned agents validated these in vitro findings. Together, these data provide unprecedented evidence that-like immune cells-geranylgeranyl-pyrophosphate depletion and thus inhibition of Rho family functions in glial cells by lovastatin promotes myelin repair in ameliorating EAE.

Pravastatin Inhibits the Rho/CCN2/extracellular matrix cascade in human fibrosis explants and improves radiation-induced intestinal fibrosis in rats

PURPOSES

Intestinal complications after radiotherapy are caused by transmural fibrosis and impair the quality of life of cancer survivors. Radiation fibrosis was considered permanent and irreversible, but recently, its dynamic nature was shown, providing new opportunities for the development of antifibrotic therapies. Among these new targets, we identified the Rho/ROCK pathway and thought to investigate whether pravastatin treatment inhibits Rho pathway activation and elicits an antifibrotic action.

EXPERIMENTAL DESIGN

Rho and ROCK activities were monitored in human explants presenting radiation fibrosis remodeling after incubation with pravastatin. Subsequent modulation of CCN2, type I collagen, and fibronectin expression were assessed ex vivo and in intestinal smooth muscle cells derived from radiation enteropathy. Then, the therapeutic relevance of the antifibrotic action of pravastatin was explored in vivo in a rat model of chronic radiation fibrosis (19 Gy X-rays) treated with 30 mg/kg/d pravastatin in the drinking water.

RESULTS

The results obtained with human explants show that pravastatin specifically inhibits Rho activity in submucosal mesenchymal cells. Pravastatin also elicits ROCK inhibition, and subsequent CCN2 production in human explants and smooth muscle cells isolated from radiation enteropathy. Inhibition of type I collagen and fibronectin does occur, showing that pravastatin modulates the secretory phenotype of mesenchymal cells. Lastly, curative pravastatin administration improves radiation enteropathy in rats. This structural improvement is associated with decreased deposition of CCN2 and subsequent decreased extracellular matrix deposition.

CONCLUSION

Targeting established fibrosis with pravastatin is an efficient and safe antifibrotic strategy in radiation-induced enteropathy, and is easily transferable into the clinic.

Simvastatin prevents the inflammatory process and the dopaminergic degeneration induced by the intranigral injection of lipopolysaccharide

Anti-inflammatory strategies have attracted much interest for their potential to prevent further deterioration of Parkinson's disease. Recent experimental and clinical evidence indicate that statins - extensively used in medical practice as effective lipid-lowering agents - have also anti-inflammatory effects. In this study, we investigated the influence of simvastatin on the degenerative process of the dopaminergic neurons of the rat following intranigral injection of lipopolysaccharide (LPS), a potent inductor of inflammation that we have previously used as an animal model of Parkinson's disease. We evaluated TH positive neurons, astroglial, and microglial populations and found that simvastatin prevented the inflammatory processes, as the induction of interleukin-1beta, tumor necrosis factor-alpha, and iNOS and the consequent dopaminergic degeneration induced by LPS. Moreover, simvastatin produced the activation of the neurotrophic factor BDNF, along with the prevention of the oxidative damage to proteins. Moreover, it also prevents the main changes produced by LPS on different mitogen-activated protein kinases, featured as increases of P-c-Jun N-terminal protein kinase, P-extracellular signal-regulated kinase, p-38, and P-glycogen synthase kinase and the decrease of the promotion of cell survival signals such as cAMP response element-binding protein and Akt. Our results suggest that statins could delay the progression of dopaminergic degeneration in disorders involving inflammatory processes.

Comparison of biochemical effects of statins and fish oil in brain: the battle of the titans

Neural membranes are composed of glycerophospholipids, sphingolipids, cholesterol and proteins. The distribution of these lipids within the neural membrane is not random but organized. Neural membranes contain lipid rafts or microdomains that are enriched in sphingolipids and cholesterol. These rafts act as platforms for the generation of glycerophospholipid-, sphingolipid-, and cholesterol-derived second messengers, lipid mediators that are necessary for normal cellular function. Glycerophospholipid-derived lipid mediators include eicosanoids, docosanoids, lipoxins, and platelet-activating factor. Sphingolipid-derived lipid mediators include ceramides, ceramide 1-phosphates, and sphingosine 1-phosphate. Cholesterol-derived lipid mediators include 24-hydroxycholesterol, 25-hydroxycholesterol, and 7-ketocholesterol. Abnormal signal transduction processes and enhanced production of lipid mediators cause oxidative stress and inflammation. These processes are closely associated with the pathogenesis of acute neural trauma (stroke, spinal cord injury, and head injury) and neurodegenerative diseases such as Alzheimer disease. Statins, the HMG-CoA reductase inhibitors, are effective lipid lowering agents that significantly reduce risk for cardiovascular and cerebrovascular diseases. Beneficial effects of statins in neurological diseases are due to their anti-excitotoxic, antioxidant, and anti-inflammatory properties. Fish oil omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid, have similar anti-excitotoxic, antioxidant and anti-inflammatory effects in brain tissue. Thus the lipid mediators, resolvins, protectins, and neuroprotectins, derived from eicosapentaenoic acid and docosahexaenoic acid retard neuroinflammation, oxidative stress, and apoptotic cell death in brain tissue. Like statins, ingredients of fish oil inhibit generation of beta-amyloid and provide protection from oxidative stress and inflammatory processes. Collective evidence suggests that antioxidant, anti-inflammatory, and anti-apoptotic properties of statins and fish oil contribute to the clinical efficacy of treating neurological disorders with statins and fish oil. We speculate that there is an overlap between neurochemical events associated with neural cell injury in stroke and neurodegenerative diseases. This commentary compares the neurochemical effects of statins with those of fish oil.