HMG-CoA reductase inhibitors inhibit inducible nitric oxide synthase gene expression in macrophages

Statin Use and Coronary Artery Calcification: a Systematic Review and Meta-analysis of Observational Studies and Randomized Controlled Trials

PURPOSE OF REVIEW

This review aimed to determine the association between statin use and coronary artery calcification (CAC), as detected by computed tomography in the general population, in previously published observational studies (OSs) and randomized controlled trials (RCTs).

RECENT FINDINGS

A systematic search until February 2022 identified 41 relevant studies, comprising 29 OSs and 12 RCTs. We employed six meta-analysis models, stratifying studies based on design and effect metrics. For cohort studies, the pooled β of the association with CAC quantified by the Agatston score was 0.11 (95% CI = 0.05; 0.16), with an average follow-up time per person (AFTP) of 3.68 years. Cross-sectional studies indicated a pooled odds ratio of 2.11 (95% CI = 1.61; 2.78) for the presence of CAC. In RCTs, the pooled standardized mean differences (SMDs) for CAC, quantified by Agatston score or volume, over and AFTP of 1.25 years were not statistically significant (SMD =  - 0.06, 95% CI =  - 0.19; 0.06 and SMD = 0.26, 95% CI =  - 0.66; 1.19), but significantly different (p-value = 0.04). Meta-regression and subgroup analyses did not show any significant differences in pooled estimates across covariates. The effect of statins on CAC differs across study designs. OSs demonstrate associations between statin use and higher CAC scores and presence while being prone to confounding by indication. Effects from RCTs do not reach statistical significance and vary depending on the quantification method, hampering drawing conclusions. Further investigations are required to address the limitations inherent in each approach.

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.

Anti-inflammatory and Antioxidant Effects of Rosuvastatin on Asthmatic, Hyperlipidemic, and Asthmatic-Hyperlipidemic Rat Models

Statins could be of potential therapeutic effect in asthma due to their pleiotropic effects on inflammation process. This study aimed to examine the possible interaction of serum lipids, and evaluate the effect of rosuvastatin treatment on asthma. Seven groups of rats, namely control (C), asthmatic (A), hyperlipidemic (H), asthmatic-hyperlipidemic (AH), rosuvastatin (40 mg/kg)-treated asthmatic (AR), rosuvastatin-treated hyperlipidemic (HR), and rosuvastatin-treated hyperlipidemic-asthmatic (AHR) groups, were studied. Total and differential WBC counts, serum oxidative stress markers, and bronchoalveolar lavage fluid (BALF) levels of IL-6 and IL-10 were evaluated. In the A and AH groups, total and differential WBC counts, and IL-6 and IL-10 levels were higher than in the C group (p<0.05 to p<0.001). An increase in nitrite and malondialdehyde concentrations and a decrease in total thiol content and superoxide dismutase and catalase activities were observed in the A, H, and AH groups compared to the C group (p<0.05 to p<0.001). Beyond lipid lowering, rosuvastatin treatment reduced total and differential WBC counts in the A and AH groups (p<0.05 to p<0.001), IL-6 level in the AH group (p<0.05), and IL-10 level in all treated groups (p<0.05). Rosuvastatin reduced oxidative stress by decreasing nitrite and malondialdehyde concentrations, and increasing total thiol content in all treated groups as well as superoxide dismutase and catalase activities in the H and AH groups (p<0.05 to p<0.01). Rosuvastatin reduced airway inflammation and oxidation through regulating NOS and reducing pro-inflammatory cytokine and inflammatory cells, which indicate a novel insight into the pleiotropic effects of rosuvastatin in treatment of asthma.

Statins and Bempedoic Acid: Different Actions of Cholesterol Inhibitors on Macrophage Activation

Statins represent the most prescribed class of drugs for the treatment of hypercholesterolemia. Effects that go beyond lipid-lowering actions have been suggested to contribute to their beneficial pharmacological properties. Whether and how statins act on macrophages has been a matter of debate. In the present study, we aimed at characterizing the impact of statins on macrophage polarization and comparing these to the effects of bempedoic acid, a recently registered drug for the treatment of hypercholesterolemia, which has been suggested to have a similar beneficial profile but fewer side effects. Treatment of primary murine macrophages with two different statins, i.e., simvastatin and cerivastatin, impaired phagocytotic activity and, concurrently, enhanced pro-inflammatory responses upon short-term lipopolysaccharide challenge, as characterized by an induction of tumor necrosis factor (TNF), interleukin (IL) 1β, and IL6. In contrast, no differences were observed under long-term inflammatory (M1) or anti-inflammatory (M2) conditions, and neither inducible NO synthase (iNOS) expression nor nitric oxide production was altered. Statin treatment led to extracellular-signal regulated kinase (ERK) activation, and the pro-inflammatory statin effects were abolished by ERK inhibition. Bempedoic acid only had a negligible impact on macrophage responses when compared with statins. Taken together, our data point toward an immunomodulatory effect of statins on macrophage polarization, which is absent upon bempedoic acid treatment.

Therapeutic effect of statins on airway remodeling during asthma

INTRODUCTION

Asthma is a chronic inflammatory disease of the airways, which is usually characterized by remodeling, hyperresponsiveness and episodic obstruction of the airways. The underlying chronic airway inflammation leads to pathological restructuring of both the large and small airways. Since the effects of current asthma medications on airway remodeling have been met with contradictions, many therapeutic agents have been redirected from their primary use for the treatment of asthma. Such treatments, which could target several signaling molecules implicated in the inflammatory and airway remodeling processes of asthma, would be an ideal choice.

AREAS COVERED

Statins are effective serum cholesterol-lowering agents that were found to have potential anti-inflammatory and anti-remodeling properties. Literature search was done for the past 10 years to include research and review articles in the field of statins and asthma complications. In this review, we discuss the role of statins in airway tissue remodeling and their potential therapeutic modalities in asthma.

EXPERT OPINION

With improved understanding of the role of statins in airway remodeling and inflammation, statins represent a potential therapeutic option for various asthma phenotypes. Further research is warranted to optimize statins for asthma therapy through inhalation as a possible route of administration.

Statins: Old drugs as new therapy for liver diseases?

In addition to lowering cholesterol levels, statins have pleiotropic effects, particularly anti-inflammatory, antiangiogenic, and antifibrotic, that may be beneficial in some chronic inflammatory conditions. Statins have only recently been investigated as a potential treatment option in chronic liver diseases because of concerns related to their safety in patients with impaired liver function. A number of experimental studies in animal models of liver diseases have shown that statins decrease hepatic inflammation, fibrogenesis and portal pressure. In addition, retrospective cohort studies in large populations of patients with cirrhosis and pre-cirrhotic conditions have shown that treatment with statins, with the purpose of decreasing high cholesterol levels, was associated with a reduced risk of disease progression, hepatic decompensation, hepatocellular carcinoma development, and death. These beneficial effects persisted after adjustment for disease severity and other potential confounders. Finally, a few randomised controlled trials have shown that treatment with simvastatin decreases portal pressure (two studies) and mortality (one study). Statin treatment was generally well tolerated but a few patients developed severe side effects, particularly rhabdomyolysis. Despite these promising beneficial effects, further randomised controlled trials in large series of patients with hard clinical endpoints should be performed before statins can be recommended for use in clinical practice.

Repurposing of statins via inhalation to treat lung inflammatory conditions

Despite many therapeutic advancements over the past decade, the continued rise in chronic inflammatory lung diseases incidence has driven the need to identify and develop new therapeutic strategies, with superior efficacy to treat these diseases. Statins are one class of drug that could potentially be repurposed as an alternative treatment for chronic lung diseases. They are currently used to treat hypercholesterolemia by inhibiting the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, that catalyses the rate limiting step in the mevalonate biosynthesis pathway, a key intermediate in cholesterol metabolism. Recent research has identified statins to have other protective pleiotropic properties including anti-inflammatory, anti-oxidant, muco-inhibitory effects that may be beneficial for the treatment of chronic inflammatory lung diseases. However, clinical studies have yielded conflicting results. This review will summarise some of the current evidences for statins pleiotropic effects that could be applied for the treatment of chronic inflammatory lung diseases, their mechanisms of actions, and the potential to repurpose statins as an inhaled therapy, including a detailed discussion on their different physical-chemical properties and how these characteristics could ultimately affect treatment efficacies. The repurposing of statins from conventional anti-cholesterol oral therapy to inhaled anti-inflammatory formulation is promising, as it provides direct delivery to the airways, reduced risk of side effects, increased bioavailability and tailored physical-chemical properties for enhanced efficacy.

Statins anticancer targeted delivery systems: re-purposing an old molecule

OBJECTIVES

Exploring the use of statins as anticancer agents and exploiting different drug delivery systems in targeting these molecules to cancerous sites. Literature review was performed to investigate the use of statins in cancer treatment in one hand, and the different pharmaceutical approaches to deliver and target these drugs to their site of action.

KEY FINDINGS

Statins were used for decades as antihypercholestrolemic drugs but recently have been proven potential for broad anticancer activities. The incorporation of statins in nanoparticulate drug delivery systems not only augmented the cytotoxicity of statins but also overcame the resistance of cancerous cells against the traditional chemotherapeutic agents. Statins-loaded nanoparticles could be easily tampered to target the cancerous cells and consequently minimal drug amount could be utilized.

SUMMARY

This review reconnoitered the different endeavors to incorporate statins in various nanoparticles and summarized the successful effects in targeting cancerous cells and reducing their proliferation without the side effects of commonly used chemotherapeutic agents.

Innovative Target Therapies Are Able to Block the Inflammation Associated with Dysfunction of the Cholesterol Biosynthesis Pathway

The cholesterol pathway is an essential biochemical process aimed at the synthesis of bioactive molecules involved in multiple crucial cellular functions. The end products of this pathway are sterols, such as cholesterol, which are essential components of cell membranes, precursors of steroid hormones, bile acids and other molecules such as ubiquinone. Several diseases are caused by defects in this metabolic pathway: the most severe forms of which cause neurological involvement (psychomotor retardation and cerebellar ataxia) as a result of a variety of cellular impairments, including mitochondrial dysfunction. These pathologies are induced by convergent mechanisms in which the mitochondrial unit plays a pivotal role contributing to defective apoptosis, autophagy and mitophagy processes. Unraveling these mechanisms would contribute to the development of effective drug treatments for these disorders. In addition, the development of biochemical models could have a substantial impact on the understanding of the mechanism of action of drugs that act on this pathway in multifactor disorders. In this review we will focus in particular on inhibitors of cholesterol synthesis, mitochondria-targeted drugs and inhibitors of the inflammasome.

Statins in Asthma: Potential Beneficial Effects and Limitations

Asthma's sustenance as a global pandemic, across centuries, can be attributed to the lack of an understanding of its workings and the inability of the existing treatment modalities to provide a long lasting cure without major adverse effects. The discovery of statins boosted by a better comprehension of the pathophysiology of asthma in the past few decades has opened up a potentially alternative line of treatment that promises to be a big boon for the asthmatics globally. However, the initial excellent results from the preclinical and animal studies have not borne the results in clinical trials that the scientific world was hoping for. In light of this, this review analyzes the ways by which statins could benefit in asthma via their pleiotropic anti-inflammatory properties and explain some of the queries raised in the previous studies and provide recommendations for future studies in this field.

Globally profiling sialylation status of macrophages upon statin treatment

Sialic acids (SAs) are widely expressed on immune cells and their levels and linkages named as sialylation status vary upon cellular environment changes related to both physiological and pathological processes. In this study, we performed a global profiling of the sialylation status of macrophages and their release of SAs in the cell culture medium by using flow cytometry, confocal microscopy and liquid chromatography tandem mass spectrometry (LC-MS/MS). Both flow cytometry and confocal microscopy results showed that cell surface α-2,3-linked SAs were predominant in the normal culture condition and changed slightly upon treatment with atorvastatin for 24 h, whereas α-2,6-linked SAs were negligible in the normal culture condition but significantly increased after treatment. Meanwhile, the amount of total cellular SAs increased about three times (from 369 ± 29 to 1080 ± 50 ng/mL) upon treatment as determined by the LC-MS/MS method. On the other hand, there was no significant change for secreted free SAs and conjugated SAs in the medium. These results indicated that the cell surface α-2,6 sialylation status of macrophages changes distinctly upon atorvastatin stimulation, which may reflect on the biological functions of the cells.

Statins stimulate atherosclerosis and heart failure: pharmacological mechanisms

In contrast to the current belief that cholesterol reduction with statins decreases atherosclerosis, we present a perspective that statins may be causative in coronary artery calcification and can function as mitochondrial toxins that impair muscle function in the heart and blood vessels through the depletion of coenzyme Q10 and 'heme A', and thereby ATP generation. Statins inhibit the synthesis of vitamin K2, the cofactor for matrix Gla-protein activation, which in turn protects arteries from calcification. Statins inhibit the biosynthesis of selenium containing proteins, one of which is glutathione peroxidase serving to suppress peroxidative stress. An impairment of selenoprotein biosynthesis may be a factor in congestive heart failure, reminiscent of the dilated cardiomyopathies seen with selenium deficiency. Thus, the epidemic of heart failure and atherosclerosis that plagues the modern world may paradoxically be aggravated by the pervasive use of statin drugs. We propose that current statin treatment guidelines be critically reevaluated.

Statins role in the prevention and treatment of sepsis

Sepsis is a complex disease with typically poor outcomes. While the onset of sepsis is typically infectious, the detrimental consequences follow pathogen toxin release that produces activation of numerous cytokines and a pro-inflammatory response. These same cytokines also stimulate activation of coagulation and inhibit natural fibrinolysis. Despite decades of research targeted against these pathways the development of sepsis and mortality in patients with sepsis remains high. While statins were developed for reducing cholesterol in patients with atherosclerotic disease, we now know they have a number of other properties which may be helpful in the prevention and treatment of sepsis. Statins have demonstrated the ability to reduce a number of pro-inflammatory cytokines known to be detrimental in the development and progression of sepsis. Statins have also demonstrated the ability to limit the coagulation response and promote fibrinolysis in the setting of sepsis. Based on these encouraging pharmacologic properties of statins a number of trials have been conducted evaluating the impact of statins on the prevention and treatment of sepsis. Most of the trials to date have been retrospective cohort trials, with very few prospective randomized trials. While some trials fail to demonstrate a benefit of statins, most trials suggest a reduction in the development of sepsis and/or other important sepsis related outcomes. While the laboratory and early clinical experience with statins are encouraging, randomized controlled trials will be need to fully define the role of statins in the prevention and treatment of sepsis.

Simvastatin local drug delivery in smokers with chronic periodontitis: a randomized controlled clinical trial

BACKGROUND

Simvastatin (SMV) is a specific competitive inhibitor of 3-hydroxy-2-methyl-glutaryl coenzyme A reductase. Statins have recently been shown to promote bone formation. This study was designed to investigate the effectiveness of SMV 1.2% in an indigenously prepared biodegradable controlled release gel as an adjunct to scaling and root planing (SRP) in the treatment of smokers with chronic periodontitis.

METHODS

Forty patients were categorized into two treatment groups: SRP plus SMV 1.2% and SRP plus placebo. Clinical parameters were recorded at baseline and at 3, 6 and 9 months; they included modified sulcus bleeding index (mSBI), probing depth (PD) and clinical attachment level (CAL). At baseline, after 6 months and 9 months, radiologic assessment of intrabony defect (IBD) fill was done using computer-aided software.

RESULTS

Mean probing depth reduction and mean clinical attachment level gain was greater in the SMV group than the placebo group at all visits. Furthermore, significantly greater mean percentage of bone fill was found in the SMV group (32.37 ± 10.23%) compared to the placebo (4.18 ± 5.39%).

CONCLUSIONS

There was a greater decrease in mSBI and PD and more CAL gain with significant IBD fill at sites treated with SRP plus locally delivered SMV in smokers with chronic periodontitis.

Long-chain fatty alcohols from evening primrose oil inhibit the inflammatory response in murine peritoneal macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Evening primrose (Oenothera biennis L., Onagraceae) is a wild medicinal plant of Central American origin that is now one of the most widely used herbal medicines in different parts of the world. Oil extracted from it seeds is traditionally used in the treatment of eczema, asthma, rheumatoid arthritis, breast problem, premenstrual and menopausal syndrome, all they have an inflammatory component. The present study demonstrates the in vitro anti-inflammatory effect of long-chain fatty alcohols, minor compounds isolated from Evening primrose oil (EPO).

MATERIAL AND METHODS

A mixture of long chain fatty alcohols (LCFAs) was isolated from the non-triacylglycerol fraction of the EPO. Hexacosanol (C26OH: 38.65%), tetracosanol (C24OH: 31.59%), docosanol (C22OH: 11.36%) and octocosanol (C28OH: 7.64%), were the major constituents, identified and quantified by GC and GC-MS. LCFA was tested with LPS stimulated murine peritoneal macrophage. This fraction, significantly and dose-dependently decreased nitric oxide production induced by LPS (P<0.001) and the inhibitory effect seems to be consequence of an action at the level of the inducible nitric-oxide synthethase (iNOS) gene enzyme expression rather than to a direct inhibitory action on enzyme activity. The release of PLA2 and TXB2 also was significantly inhibited by LCFAs (P<0.001) although LCFAs did not affect to PGE2 generation, however the western blot assay showed that LCFAs reduced cyclooxygenase-2 enzyme gene expression at all doses assayed. In the same way, the secretion of inflammatory cytokines interleukin 1β (IL-1β) and tumour necrosis factor α (TNF-α) from LPS-stimulated murine macrophage, were also significantly reduced (P<0.001).

CONCLUSION

These results demonstrates the anti-inflammatory activity of LCFAs, providing an additional value about the role of bioactive minor compounds in the beneficial effect of EPO and supports its traditional uses in inflammatory processes management.

Statins decrease lung inflammation in mice by upregulating tetraspanin CD9 in macrophages

Tetraspanins organize protein complexes in tetraspanin-enriched membrane microdomains that are distinct from lipid rafts. Our previous studies suggested that reduction in the levels of tetraspanins CD9 and CD81 may be involved in the progression of inflammatory lung diseases, especially COPD. To search for agents that increase the levels of these tetraspanins, we screened 1,165 drugs in clinical use and found that statins upregulate CD9 and CD81 in RAW264.7 macrophages. The lipophilic statins, fluvastatin and simvastatin, reversed LPS-induced downregulation of CD9 and CD81, simultaneously preventing TNF-α and matrix metalloproteinase-9 production and spreading of RAW264.7 cells. These statins exerted anti-inflammatory effects in vitro in wild-type macrophages but not in CD9 knockout macrophages, and decreased lung inflammation in vivo in wild-type mice but not in CD9 knockout mice, suggesting that their effects are dependent on CD9. Mechanistically, the statins promoted reverse transfer of the LPS-signaling mediator CD14 from lipid rafts into CD9-enriched microdomains, thereby preventing LPS receptor formation. Finally, upregulation of CD9/CD81 by statins was related to blockade of GTPase geranylgeranylation in the mevalonate pathway. Our data underscore the importance of the negative regulator CD9 in lung inflammation, and suggest that statins exert anti-inflammatory effects by upregulating tetraspanin CD9 in macrophages.

Simvastatin induces caspase-dependent apoptosis and activates P53 in OCM-1 cells

Simvastatin is a cholesterol-lowering drug which exhibits numerous pleiotropic effects including anti-cancer activity. Yet, the anti-cancer effects in choroidal melanoma remain poorly characterized. Therefore, in this study, we investigated the effects of simvastatin on OCM-1 cells growth, apoptosis and cycle. Simvastatin showed an inhibitory effects on OCM-1 cells viability in dose-dependent (2-10 μM) and time-dependent (24-72 h) manner. Further study suggested that simvastatin-induced inhibition OCM-1 cells proliferation was associated with G1 phase arrest, decreased protein and mRNA expression of proliferation marker cyclin D1, cyclin E, cyclin dependent kinase (CDK)2 and increased expression of CDK inhibitory protein P21. In addition, simvastatin resulted in an increase in levels of reactive oxygen species (ROS) in OCM-1 cells and simvastatin significantly triggered apoptosis in OCM-1 cells, which was characterized by increased chromatin condensation, activation of caspase-9 and cleaved-caspase-3, increased expression mitochondrion-related apoptosis protein of P53, Bax and decreased expression of Bcl2 and iASPP. Collectively, our study demonstrated that simvastatin can efficiently inhibit proliferation and induce apoptosis in OCM-1 cells.

Treatment With Low-dose Atorvastatin, Losartan, and Their Combination Increases Expression of Vasoactive-Related Genes in Rat Aortas

Recently it has been shown that statins and angiotensin receptor blockers (ARBs) at low doses express beneficial pleiotropic vascular effects. We aimed to explore whether these drugs at low doses induce the expression of vasoactive-related genes. Sixty adult Wistar rats were treated with low-dose atorvastatin (2 mg/kg), low-dose losartan (5 mg/kg), their combination or saline daily for 4, 6, or 8 weeks. Expression of the vasoactive-related genes endothelin receptor type A ( EDNRA), endothelial nitric oxide synthase 3 ( NOS3), inducible nitric oxide synthase 2 ( NOS2), and angiotensin II receptor type 1 ( AGTRL1a) was measured in isolated thoracic aortas. Expression of EDNRA gradually decreased, the lowest values being obtained after 8 weeks (low-dose atorvastatin, losartan [1.6- and 1-7-fold vs controls, respectively; both P < .05], and the combination [2.3-fold vs control, P < .001]). The highest values of NOS3 were obtained after 6 weeks (low-dose atorvastatin, losartan, and their combination, 3.1-fold, P < .01; 3.4-fold, P < .001; and 3.6-fold, P < .001 vs controls, respectively) and then declined after 8 weeks. The combination was more effective in inducing total NOS3 expression when compared to the separate drugs (1.4-fold; P < .05). Importantly, expression of NOS3 was associated with increased plasma NO levels and positively correlated with thoracic aorta relaxation. No changes in expression of NOS2 and AGTRL1a were observed. We showed that low-dose atorvastatin or losartan and especially their combination increases the expression of NOS3 and decreases the expression of EDNRA. These findings are valuable in explaining the effectiveness of the “low-dose pharmacological approach” for improvement in arterial function.

HMG-CoA Reductase Inhibitors for Prevention and Treatment of Severe Sepsis

HMG-CoA reductase inhibitors, or statins, are among the most commonly prescribed pharmaceuticals in the world, especially among the elderly. The remarkable conjuncture of this fact with the rising incidence of severe sepsis among people over age 65 could prove to be of serendipitous benefit, because numerous actions of the statins make them of potential use in the prevention and treatment of severe sepsis. Severe sepsis continues to be a highly lethal condition, for which there are, as yet, no effective pharmacological treatments, save antibiotics. We explore the biological plausibility of statins as prophylaxis agents and as treatment for severe sepsis and thoroughly review the preclinical and clinical studies that have explored the effects of statins in infected and septic patients. Statins remain only promising treatments for severe sepsis, without convincing evidence that they reduce patient mortality. Ongoing randomized trials may provide conclusive evidence, whether positive or negative.

Statins in the critically ill

The use or misuse of statins in critically ill patients recently attracted the attention of intensive care clinicians. Indeed, statins are probably the most common chronic treatment before critical illness and some recent experimental and clinical data demonstrated their beneficial effects during sepsis, acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), or after aneurismal subarachnoidal hemorrhage (aSAH). Due to the heterogeneity of current studies and the lack of well-designed prospective studies, definitive conclusions for systematic and large-scale utilization in intensive care units cannot be drawn from the published evidence. Furthermore, the extent of statins side effects in critically ill patients is still unknown. For the intensive care clinician, it is a matter of individually identifying the patient who can benefit from this therapy according to the current literature. The purpose of this review is to describe the mechanisms of actions of statins and to synthesize the clinical data that underline the relevant effects of statins in the particular setting of critical care, in an attempt to guide the clinician through his daily practice.

Statins in sepsis

Sepsis is a common intensive care unit event occurring in approximately 750 000 patients annually, with a case mortality rate approaching 50%. Sepsis is characterized by a chaotic and excessive release of inflammatory cytokines and procoagulants including tumor necrosis factor, interleukin (IL)-1, IL-6, IL-8, platelet-activating factor, and tissue factor. Efforts to inhibit individual cytokines in order to modify poor outcomes have been generally disappointing, suggesting the need to target multiple inflammatory mediators to obtain clinical benefit. Statins lower lipids by inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, which in turn inhibits the rate-limiting step in cholesterol biosynthesis. In addition to lowering total cholesterol, statins have pleiotropic effects on inflammation and immunity. Instead of impacting a single entity in the sepsis syndrome, statins may have positive effects on multiple inflammatory, immunomodulating, and coagulation targets involved in the development of infection and sepsis. There have been a number of institutional- and population-based studies that have evaluated the impact of statins in patients with infection and sepsis. Most of these studies, but not all, have demonstrated a number of positive outcomes in patients with statins, including reduction in mortality. Based on these data, statins are a promising therapy in the management of patients with sepsis and warrant larger and more rigorous clinical trials.

Statin therapy reduces growth of abdominal aortic aneurysms

BACKGROUND

The aim of this study was to evaluate the influence of statins on the growth of small abdominal aortic aneurysms (AAAs).

METHODS

We retrospectively examined AAA diameter in 211 patients who had undergone serial imaging surveillance.

RESULTS

Patients treated with and without statins were similar regarding age, initial aneurysm size, diagnosis of diabetes and hypertension, and smoking history. Patients receiving statins had a decreased aneurysm growth rate compared with those patients not receiving statins (0.9 mm/y [interquartile range, -1.0 to +1.0] vs 3.2 mm/y [interquartile range, 2.0-4.9], P < 0.0001). This difference in the rate of growth was maintained after adjusting for potential confounding factors.

CONCLUSIONS

To date, this is the one of the largest retrospective studies demonstrating an association between statin use and decreased growth rate of AAA.

Atorvastatin treatment is effective when used in combination with mefloquine in an experimental cerebral malaria murine model

BACKGROUND

One of the major complications of Plasmodium falciparum infection is cerebral malaria (CM), which causes one million deaths worldwide each year, results in long-term neurological sequelae and the treatment for which is only partially effective. Statins are recognized to have an immunomodulatory action, attenuate sepsis and have a neuroprotective effect. Atorvastatin (AVA) has shown in vitro anti-malarial activity and has improved the activity of mefloquine (MQ) and quinine.

METHODS

The efficiency of 40 mg/kg intraperitoneal AVA, alone or in association with MQ, was assessed in an experimental Plasmodium berghei ANKA rodent parasite model of CM and performed according to different therapeutic schemes. The effects on experimental CM were assessed through the evaluation of brain histopathological changes and neuronal apoptosis by TUNEL staining.

RESULTS

AVA alone in the therapeutic scheme show no effect on survival, but the prophylactic scheme employing AVA associated with MQ, rather than MQ alone, led to a significant delay in mouse death and had an effect on the onset of CM symptoms and on the level of parasitaemia. Histopathological findings show a correlation between brain lesions and CM onset. A neuronal anti-apoptotic effect of AVA in the AVA + MQ combination was not shown.

CONCLUSIONS

The combination of AVA and MQ therapy led to a significant delay in mouse mortality. There were differences in the incidence, time to cerebral malaria and the level of parasitaemia when the drug combination was administered to mice. When used in combination with MQ, AVA had a relevant effect on the in vivo growth inhibition and clinical outcome of P. berghei ANKA-infected mice.

Prior use of 3-hydroxy-3-methyl-glutaryl-coenzyme a reductase inhibitor, simvastatin fails to improve outcome after experimental intracerebral hemorrhage

OBJECTIVE

Contrary to some clinical belief, there were quite a few studies regarding animal models of intracerebral hemorrhage (ICH) in vivo suggesting that prior use of statins may improve outcome after ICH. This study reports the effect of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG CoA) reductase inhibitor, simvastatin given before experimental ICH.

METHODS

Fifty-one rats were subjected to collagenase-induced ICH, subdivided in 3 groups according to simvastatin treatment modality, and behavioral tests were done. Hematoma volume, brain water content and hemispheric atrophy were analyzed. Immunohistochemical staining for microglia (OX-42) and endothelial nitric oxide synthase (eNOS) was performed and caspase-3 activity was also measured.

RESULTS

Pre-simvastatin therapy decreased inflammatory reaction and perihematomal cell death, but resulted in no significant reduction of brain edema and no eNOS expression in the perihematomal region. Finally, prior use of simvastatin showed less significant improvement of neurological outcome after experimental ICH when compared to post-simvastatin therapy.

CONCLUSION

The present study suggests that statins therapy after ICH improves neurological outcome, but prior use of statins before ICH might provide only histological improvement, providing no significant impact on neurological outcome against ICH.

Simvastatin as add-on therapy to interferon β-1a for relapsing-remitting multiple sclerosis (SIMCOMBIN study): a placebo-controlled randomised phase 4 trial

BACKGROUND

Treatment of relapsing-remitting multiple sclerosis with interferon beta is only partly effective. We aimed to establish whether add-on of simvastatin, a statin with anti-inflammatory properties, improves this efficacy.

METHODS

We enrolled treatment-naive patients with relapsing-remitting multiple sclerosis in a multicentre, placebo-controlled, double-blind, randomised, parallel-group trial of simvastatin (80 mg daily) as add-on treatment to intramuscular interferon beta-1a (30 μg weekly). After starting treatment with interferon beta, patients were randomly assigned (in computer-generated blocks of four patients) to simvastatin 80 mg per day or placebo for 1-3 years. Patients and treating and evaluating physicians were masked to treatment allocation. The primary outcome measure was annual rate of documented relapses; analysis was by intention to treat. This trial is registered at ClinicalTrials.gov, NCT00492765.

FINDINGS

We randomly assigned 307 patients to interferon beta plus simvastatin (n=151) or plus placebo (n=156). Annual rate of documented relapses was 0·19 (95% CI 0·13 to 0·28) in the simvastatin group and 0·14 (95% CI 0·09 to 0·23) in the placebo group (absolute difference 0·059, 95% CI -0·21 to 0·09; p=0·35). Time to first documented relapse (20th percentile) was 18·1 months in patients on simvastatin and 21·5 months in those on placebo (hazard ratio 1·21, 95% CI 0·74 to 1·99; p=0·51). Mean number of new or enlarging T2 lesions was 2·96 in the simvastatin group and 2·52 in the placebo group (ratio of new lesions, 1·17, 95% CI 8·89 to 1·55; p=0·25). Eight (6%) patients on simvastatin and 17 (13%) on placebo had no disease activity (odds ratio 0·42, 95% CI 0·17 to 1·00; p=0·05). No unexpected adverse events were seen. Generally, adverse events were mild and there were no group differences in infections or musculoskeletal disorders, including myalgia (five [3%] patients on simvastatin and nine [6%] on placebo). Rhabdomyolysis and myoglobinuria were not reported and there were no differences in serum creatine phosphokinase.

INTERPRETATION

We found no beneficial effect of simvastatin as add-on therapy to interferon beta-1a. Although unlikely, we can not exclude that combination of other statins with other disease-modifying drugs still could be beneficial.

FUNDING

Biogen Idec.

Statins and brain dysfunction: a hypothesis to reduce the burden of cognitive impairment in patients who are critically ill

Delirium is a frequent form of acute brain dysfunction in patients who are critically ill and is associated with poor clinical outcomes, including a critical illness brain injury that may last for months to years. Despite widespread recognition of significant adverse outcomes, pharmacologic approaches to prevent or treat delirium during critical illness remain unproven. We hypothesize that commonly prescribed statin medications may prevent and treat delirium by targeting molecular pathways of inflammation (peripheral and central) and microglial activation that are central to the pathogenesis of delirium. Systemic inflammation, a principal mechanism of injury, for example, in sepsis, acute respiratory distress syndrome, and other critical illnesses, can cause neuronal apoptosis, blood-brain barrier injury, brain ischemia, and microglial activation. We hypothesize that the known pleiotropic effects of statins, which attenuate such neuroinflammation, may redirect microglial activation and promote an antiinflammatory phenotype, thereby offering the potential to reduce the public health burden of delirium and its associated long-term cognitive injury.

Red Mold Rice Mitigates Oral Carcinogenesis in 7,12-Dimethyl-1,2-Benz[a]anthracene-Induced Oral Carcinogenesis in Hamster

The prevalence of oral tumor has exponentially increased in recent years; however, the effective therapies or prevention strategies are not sufficient. Red mold rice is a traditional Chinese food, and several reports have demonstrated that red mold rice had an anti-tumor effect. However, the possible anti-tumor mechanisms of the red mold rice are unclear. In this study, we examined the anti-tumor effect of red mold rice on 7,12-dimethyl-1,2-benz[a]anthracene (DMBA)-induced oral tumor in hamster. The ethanol extract of red mold rice (RMRE) treatment significantly decreases the levels of DMBA-induced reactive oxygen species, nitro oxide and prostaglandin E₂ than those of the lovastatin-treated group (P < .001). Moreover, RMRE decreases the formation of oral tumor induced by DMBA. Monacolin K, monascin, ankaflavin or other red mold rice metabolites had been reported to decrease inflammation and oxidative stress and exerted anti-tumor effects. Therefore, we evaluated the anti-inflammation and anti-oxidative stress effects of monacolin K, monascin, ankaflavin and citrinin in lipopolysaccharide-treated RAW264.7 cells. We found that RMRE reduced the LPS-induced nitrite levels in RAW264.7 cells better than monacolin K, monascin, ankaflavin or citrinin (P < .05).

The pleiotropic effects of statins and omega-3 fatty acids against sepsis: a new perspective

The available therapeutic options for sepsis are restricted by their effectiveness and high cost. Emerging preliminary data suggest that statins and omega-3 fatty acids (OM3FA) may be associated with improved outcomes in terms of prevention and treatment of sepsis. We sought to review the current evidence on the effectiveness of their combined administration against sepsis, by carrying out a review of PubMed and Scopus databases for relevant studies, without imposing language or time restrictions. No clinical studies were identified regarding the effect of the combination treatment with statins and OM3FA on sepsis in terms of prevention or treatment. However, there is experimental evidence that both statins and OM3FA inhibit the inflammatory process at different levels, but also enhance inhibition at those levels that are common. There are also preliminary data supporting the beneficial effect of this combination on platelet function and other haemostatic mechanisms. Appropriately designed and powered clinical trials are warranted to investigate the effectiveness and safety of the combined administration of statins and OM3FA for the prevention and treatment of sepsis.

Simvastatin improves epithelial dysfunction and airway hyperresponsiveness: from asymmetric dimethyl-arginine to asthma

Altered arginine metabolism, the uncoupling of nitric oxide synthase (NOS) by asymmetric dimethyl-arginine (ADMA), increased oxo-nitrosative stress, and cellular injury were reported in airway epithelial cells in asthma. Statins improve vascular endothelial dysfunction by reducing ADMA and increasing endothelial NOS (eNOS), thereby reducing oxo-nitrosative stress in cardiovascular diseases. Whether statin therapy leads to similar beneficial effects in lung epithelium in asthma is unknown. The effects of simvastatin therapy after sensitization (40 mg/kg, intraperitoneally) on markers of arginine and NO metabolism and features of asthma were ascertained in a murine model of allergic asthma. The effects of simvastatin on the expression of NOS in A549 lung epithelial cells were studied in vitro. Simvastatin induced eNOS in lung epithelial cells in vitro. In acute and chronic models of asthma, simvastatin therapy was associated with significantly reduced airway inflammation, airway hyperresponsiveness, and airway remodeling. ADMA and inducible nitric oxide synthase were reduced by simvastatin, but eNOS was increased. A marked reduction of nitrotyrosine, a marker of oxo-nitrosative stress, was evident in airway epithelium. Cell injury markers such as cytosolic cytochrome c, caspases 3 and 9 and apoptotic protease activating factor 1 (Apaf-1) were also reduced. Simvastatin improves dysfunctional nitric oxide metabolism in allergically inflamed lungs. Important pleiotropic mechanisms may be responsible for the statin-induced reduction of airway inflammation, epithelial injury, and airway hyperresponsiveness.

Cyclic nucleotides and mitogen-activated protein kinases: regulation of simvastatin in platelet activation

Background

3-Hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have been widely used to reduce cardiovascular risk. These statins (i.e., simvastatin) may exert other effects besides from their cholesterol-lowering actions, including inhibition of platelet activation. Platelet activation is relevant to a variety of coronary heart diseases. Although the inhibitory effect of simvastatin in platelet activation has been studied; the detailed signal transductions by which simvastatin inhibit platelet activation has not yet been completely resolved.

Methods

The aim of this study was to systematically examine the detailed mechanisms of simvastatin in preventing platelet activation. Platelet aggregation, flow cytometric analysis, immunoblotting, and electron spin resonance studies were used to assess the antiplatelet activity of simvastatin.

Results

Simvastatin (20-50 μM) exhibited more-potent activity of inhibiting platelet aggregation stimulated by collagen than other agonists (i.e., thrombin). Simvastatin inhibited collagen-stimulated platelet activation accompanied by [Ca²⁺]i mobilization, thromboxane A₂ (TxA₂) formation, and phospholipase C (PLC)γ2, protein kinase C (PKC), and mitogen-activated protein kinases (i.e., p38 MAPK, JNKs) phosphorylation in washed platelets. Simvastatin obviously increased both cyclic AMP and cyclic GMP levels. Simvastatin markedly increased NO release, vasodilator-stimulated phosphoprotein (VASP) phosphorylation, and endothelial nitric oxide synthase (eNOS) expression. SQ22536, an inhibitor of adenylate cyclase, markedly reversed the simvastatin-mediated inhibitory effects on platelet aggregation, PLCγ2 and p38 MAPK phosphorylation, and simvastatin-mediated stimulatory effects on VASP and eNOS phosphorylation.

Conclusion

The most important findings of this study demonstrate for the first time that inhibitory effect of simvastatin in platelet activation may involve activation of the cyclic AMP-eNOS/NO-cyclic GMP pathway, resulting in inhibition of the PLCγ2-PKC-p38 MAPK-TxA₂ cascade, and finally inhibition of platelet aggregation.

Decreased ubiquinone availability and impaired mitochondrial cytochrome oxidase activity associated with statin treatment

In order to investigate the potential involvement of mitochondrial electron transport chain (ETC) dysfunction in myotoxicity associated with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor (statin) treatment, assessment was made of ETC activity and ubiquinone status in two patients experiencing myopathy following treatment with simvastatin (40 mg/day) and cyclosporin (patient 1) and simvastatin (40 mg/day) and itraconazole (patient 2). Analysis of skeletal muscle biopsies revealed a decreased ubiquinone status (77 and 132; reference range: 140-580 pmol/mg) and cytochrome oxidase (complex IV) activity (0.006 and 0.007 reference range: 0.014-0.034). To assess statin treatment in the absence of possible pharmacological interference from cyclosporin or itraconazole, primary astrocytes were cultured with lovastatin (100 microM). Lovastatin treatment resulted in a decrease in ubiquinone (97.9 +/- 14.9; control: 202.9 +/- 18.4 pmol/mg; p < 0.05), and complex IV activity (0.008 +/- 0.001; control: 0.011 +/- 0.001; p < 0.05) relative to control. These data, coupled with the patient findings, indicate a possible association between statin treatment, decreased ubiquinone status, and loss of complex IV activity.

Involvement of HSP70 in the protection of bicyclol on apoptosis of HepG2 cells intoxicated by d-galactosamine

Heat shock proteins (HSPs), the best known endogenous factors, play important roles in the cytoprotection and repair of cells and tissues against the harmful effects of stress and insults. In this study, RNAi technology was used to identify whether HSP70 was involved in the protection of bicyclol against d-galactosamine (d-GaIN)-induced apoptosis in HepG2 cells. As a result, bicyclol induced HSP70 in a time- and dose-dependent manner in HepG2 cells. Bicyclol markedly alleviated apoptosis and caspase-3 activity in HepG2 cells intoxicated by d-GaIN. The degradation of inhibitory kappa B, phosphorylation of inhibitory kappa B kinase, nuclear factor kappa B (NF-kappaB) nuclear translocation, and DNA-binding activity were all inhibited by bicyclol in HepG2 cells intoxicated by d-GaIN. In addition, bicyclol decreased the nitric oxide production and inducible nitric oxide synthase (iNOS) expression. The inhibitory effects of bicyclol on all the above biomarkers were attenuated when the HSP70 gene was silenced accordingly. Our data also showed that MG132 (inhibitor of NF-kappaB) and NG-nitro-l-arginine methyl ester (inhibitor of iNOS) inhibited hepatocyte apoptosis induced by d-GaIN. These in vitro results suggested that HSP70 partially contributed to the hepatoprotection of bicyclol through suppressing the NF-kappaB-iNOS pathway.

Beneficial microvascular and anti-inflammatory effects of pravastatin during sepsis involve nitric oxide synthase III

BACKGROUND

Sepsis induces microvascular inflammation and production of the vasodilator nitric oxide (NO) via endothelial and inducible nitric oxide synthase (eNOS or NOS III and iNOS or NOS II). Statins are cholesterol-lowering drugs; however, they also attenuate inflammation. This study aimed to determine whether pravastatin protected against sepsis-induced hypotension, loss of vascular tone, and microvascular inflammation via NOS pathways.

METHODS

Male Wistar rats (n=18) were anaesthetized and the mesentery prepared for fluorescent intravital microscopy. Animals received either lipopolysaccharide (LPS; n=6); LPS+pravastatin (18 and 3 h before LPS; n=6), or saline as a control, for 4 h.

RESULTS

Mean arterial pressure decreased in LPS-treated animals (P<0.05), but not in those also receiving pravastatin. Acetylcholine-induced relaxation of venules was abolished by LPS but improved by pravastatin. Pravastatin also reduced the increase in nitrite concentration and macromolecular leak from venules induced by LPS (P<0.05). The increased leucocyte adhesion seen in LPS-treated rats was also reduced in those also treated with pravastatin. Immunohistochemical analysis showed that pravastatin increased endothelial cell expression of NOS III during sepsis, but had no effect on LPS-induced up-regulation of NOS II.

CONCLUSIONS

Pravastatin improved NOS III-mediated vessel relaxation and exerted anti-inflammatory effects within the microcirculation after LPS administration in rats. Pravastatin therefore appears to have beneficial effects during sepsis, as a result of increased microvascular expression and function of NOS III.

Can statins suppress the development of abdominal aortic aneurysms? A review of the current evidence

Statins possess several pleiotropic effects and have been shown in vitro and in vivo to inhibit the expression of inflammatory mediators and downregulate molecules involved in extracellular matrix (ECM) degradation. Recent observational studies in humans suggest that statins may have a role in abdominal aortic aneurysm (AAA) prevention or may even inhibit aneurysm expansion. In this review, we summarize the effects of statins on the vessel wall of aneurysmal aortas and currently available data concerning their inhibitory effects on aneurysm progression.

Homocysteine modulates the effect of simvastatin on expression of ApoA-I and NF-kappaB/iNOS

AIMS

Statins can ameliorate atherosclerosis by inhibition of cholesterol biosynthesis or by modulation of inflammation. In earlier work, we showed that homocysteine (Hcy) reduced synthesis of apolipoprotein A-I (ApoA-I). Our goal in this study was to determine whether Hcy could interfere with the ability of simvastatin to increase ApoA-I synthesis or to modify statin-dependent regulation of inflammatory factors.

METHODS AND RESULTS

Human HepG2 hepatocarcinoma cells and murine RAW264.7 macrophages were treated with simvastatin, with and without Hcy, to examine the expression of ApoA-I and nuclear factor-kappaB (NF-kappaB) or the NF-kappaB target, inducible nitric-oxide synthase (iNOS), respectively. Mice with methylenetetrahydrofolate reductase (Mthfr) deficiency, an animal model of hyperhomocysteinemia, were administered simvastatin (in diets or by injection) for in vivo assessment of these interactions. In HepG2 cells, Hcy reduced the statin-dependent increases in ApoA-I protein, mRNA, and ApoA-I promoter activity. In RAW264.7 macrophages, simvastatin decreased, whereas Hcy increased, the expression of pro-inflammatory NF-kappaB protein; in the presence of both Hcy and simvastatin, the pro-inflammatory effect of Hcy prevailed. Hcy increased mRNA levels of iNOS in the macrophage line; the combination of Hcy and simvastatin resulted in a trend towards greater induction. In mouse studies, simvastatin decreased cholesterol levels, but levels of ApoA-I in Mthfr-deficient mice remained lower than those in Mthfr(+/+) mice. Simvastatin injection increased iNOS protein and mRNA levels in peripheral blood of hyperhomocysteinemic Mthfr-deficient mice, but not in Mthfr(+/+) mice. The drug also increased MTHFR protein in cells and mouse liver, an effect that was modified by Hcy.

CONCLUSION

These findings provide a link between statins and folate-dependent Hcy metabolism, and suggest that Hcy interferes with some anti-atherogenic and anti-inflammatory properties of simvastatin. Our work may have clinical relevance for hyperhomocysteinemic individuals on statin therapy.

Simvastatin suppresses the progression of experimentally induced cerebral aneurysms in rats

BACKGROUND AND PURPOSE

The pathophysiology of cerebral aneurysms (CAs) is linked to chronic inflammation and degradation of extracellular matrix in vascular walls. Because statins have protective effects on various vascular diseases independent of their lipid-lowering effects, we investigated the effect of simvastatin on CA progression.

METHODS

CAs were induced in Sprague-Dawley rats with or without oral administration of simvastatin. The size and media thickness of CAs was evaluated 3 months after aneurysm induction. Expression of macrophage chemoattractant protein-1, vascular cell adhesion molecule-1, endothelial nitric oxide synthase, interleukin-1beta, inducible nitric oxide synthase, matrix metalloproteinase-2, and matrix metalloproteinase-9 in aneurysmal walls was examined by reverse transcriptase-polymerase chain reaction and immunohistochemistry. To examine whether simvastatin has a suppressive effect on preexisting CAs, simvastatin administration started at 1 month after aneurysm induction.

RESULTS

Rats treated with simvastatin exhibited a significant increase in media thickness and a significant reduction in aneurysmal size compared with control rats. Treatment with simvastatin resulted in reduced expression of macrophage chemoattractant protein-1 and vascular cell adhesion molecule-1, increased expression of endothelial nitric oxide synthase, and reduced the number of macrophage infiltration. In quantitative polymerase chain reaction and immunohistochemistry, simvastatin significantly inhibited upregulated expression of interleukin-1beta, inducible nitric oxide synthase, matrix metalloproteinase-2, and matrix metalloproteinase-9 associated with CA progression. Gelatin zymography revealed decreased activity of matrix metalloproteinase-2 and matrix metalloproteinase-9 in aneurysmal walls by simvastatin treatment. Simvastatin also effectively inhibited aneurysm enlargement and thinning of the media of preexisting CAs.

CONCLUSIONS

Treatment with simvastatin suppresses the development of CAs by inhibiting inflammatory reactions in aneurysmal walls. Simvastatin also has a preventive effect on the progression of preexisting CAs. Simvastatin is a promising candidate of a novel medical treatment for the prevention of CA progression.

Enhanced nitric oxide and cyclic GMP formation plays a role in the anti-platelet activity of simvastatin

BACKGROUND AND PURPOSE

It has been found that 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) exert various vascular protective effects, beyond their cholesterol-lowering property, including inhibition of platelet-dependent thrombus formation. The objective of the present study was to determine whether the nitric oxide (NO)/cyclic GMP-mediated processes in platelets contribute to the anti-aggregatory activity of simvastatin.

EXPERIMENTAL APPROACH

After rabbit platelets were incubated with simvastatin for 5 min, aggregation was induced and the platelet aggregation, nitric oxide synthase activity, guanylyl cyclase activity, NO and cyclic GMP formation were measured appropriately.

KEY RESULTS

Treatment with simvastatin concentration-dependently inhibited platelet aggregation induced by collagen or arachidonic acid with an IC(50) range of 52-158 microM. We also demonstrated that simvastatin (20-80 microM) concentration-dependently further enhanced collagen-induced NO and cyclic GMP formation through increasing NOS activity (from 2.64+/-0.12 to 3.52+/-0.21-5.10+/-0.14 micromol min(-1) mg protein(-1)) and guanylyl cyclase activity (from 142.9+/-7.2 to 163.5+/-17.5-283.8+/-19.5 pmol min(-1) mg protein(-1)) in the platelets. On the contrary, inhibition of platelet aggregation by simvastatin was markedly attenuated (by about 50%) by addition of a nitric oxide synthase inhibitor, a NO scavenger or a NO-sensitive guanylyl cyclase inhibitor. The anti-aggregatory effects of simvastatin were significantly increased by addition of a selective inhibitor of cyclic GMP phosphodiesterase.

CONCLUSIONS AND IMPLICATIONS

Our findings indicate that enhancement of a NO/cyclic GMP-mediated process plays an important role in the anti-aggregatory activity of simvastatin.

Simvastatin enhances induction of inducible nitric oxide synthase in 3T3-L1 adipocytes

The present study was designed to determine whether hydroxymethylglutaryl-CoA reductase inhibitors (statins) modulate the NO production via iNOS in adipocytes stimulated by lipopolysaccharide (L) and tumour necrosis factor-alpha (T). Well-differentiated 3T3-L1 adipocytes significantly produced NO by LT-treatment. Pre-incubation with simvastatin, a lipophilic statin, pravastatin, a hydrophilic one, or Y27632, an inhibitor of Rho kinase, further enhanced the production of NO. The effect of simvastatin was offset by mevalonate and geranylgeranyl pyrophosphate (GGPP) but not by squalene. The mRNA level for iNOS parallelled the NO production. The NF-kappaB was activated by the LT-treatment and was further enhanced by simvastatin, pravastatin or Y27632 addition. Mevalonate and GGPP completely offset the effect of simvastatin. Statins and Y27632 also further increased the interleukin-6 secretion in the LT-treated 3T3-L1 adipocytes. These results suggest that statins, especially lipophilic type, enhance induction of iNOS by inhibiting the small GTP-binding protein signal in adipocytes.

Role of matrix metalloproteinase inhibitors in preventing abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a significant health problem in the United States, with approximately 30,000 repair operations annually. Treatment of AAA is associated with more than 150,000 hospital admissions per year. The development of AAA is characterized by destruction of the elastic media of the aortic wall. A large body of evidence suggests that a group of enzymes called matrix metalloproteinases (MMPs) plays a significant role in the destruction of extracellular matrix in the aortic wall. MMP inhibition has, therefore, been viewed as an alternative pharmacotherapeutic approach to slow down the development and progression of small AAAs, thus reducing the need for surgical intervention.

Fluvastatin ameliorates endotoxin induced multiple organ failure in conscious rats

OBJECTIVES

Sepsis is a severe inflammatory disorder that may lead to multiple organ failure. Lipopolysaccharide (LPS) is associated with Gram-negative sepsis and can activate monocytes and macrophages to release pro-inflammatory mediators such as tumor necrosis factor-alpha (TNF-alpha), nitric oxide (NO) and anti-inflammatory mediator such as interleukin-10 (IL-10). In this present study, we used fluvastatin, a HMG-CoA reductase inhibitor, to study its effects upon LPS-induced endotoxic shock in conscious rats.

METHODS

The experiments were designed that rats received an intravenous injection of 1mg/kg fluvastatin followed 10min later, by an intravenous injection of 10mg/kg Klebsiella pneumoniae LPS, the latter inducing endotoxic shock amongst conscious rats. Subsequently, the levels of certain biochemical variables and cytokines in serum were then measured during the ensuing 48-h period following sepsis. These included total cholesterol (TCH), triglyceride (TG), blood urea nitrogen (BUN), creatinine (Cre), creatine phosphokinase (CPK), lactic dehydrogenase (LDH), aspartate transferase (GOT), alanine transferase (GPT), tumor necrosis factor-alpha, interleukin-10 and nitric oxide.

RESULTS

LPS significantly increased blood TG, BUN, Cre, LDH, CPK, GOT, GPT, TNF-alpha, IL-10 and NO levels but decreased the blood TCH level. Pretreatment of test rats with fluvastatin decreased blood levels of certain markers of organ injury, suppressed the release of TNF-alpha and increased IL-10, and NO levels following LPS treatment. Fluvastatin did not affect the blood TCH and TG level subsequent to the development of sepsis.

CONCLUSIONS

Pre-treatment with fluvastatin suppresses the release of plasma TNF-alpha, increases plasma IL-10, and NO production, and decreases the levels of markers of organ injury associated with endotoxic shock, so ameliorating LPS-induced organ damage amongst conscious rats.