Modulation of inflammatory mediators and PPARgamma and NFkappaB expression by pravastatin in response to lipoproteins in human monocytes in vitro

Identification and analysis of the molecular targets of statins in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world. According to several types of research, statins may impact the development and treatment of CRC. This work aimed to use bioinformatics to discover the relationship between statin targets and differentially expressed genes (DEGs) in CRC patients and determine the possible molecular effect of statins on CRC suppression. We used CRC datasets from the GEO database to select CRC-related DEGs. DGIdb and STITCH databases were used to identify gene targets of subtypes of statin. Further, we identified the statin target of CRC DEGs hub genes by using a Venn diagram of CRC DEGs and statin targets. Funrich and enrichr databases were carried out for the KEGG pathway and gene ontology (GO) enrichment analysis, respectively. GSE74604 and GSE10950 were used to identify CRC DEGs. After analyzing datasets,1370 genes were identified as CRC DEGs, and 345 targets were found for statins. We found that 35 genes are CRC DEGs statin targets. We found that statin targets in CRC were enriched in the receptor and metallopeptidase activity for molecular function, cytoplasm and plasma membrane for cellular component, signal transduction, and cell communication for biological process genes were substantially enriched based on FunRich enrichment. Analysis of the KEGG pathways revealed that the overexpressed DEGs were enriched in the IL-17, PPAR, and Toll-like receptor signaling pathways. Finally, CCNB1, DNMT1, AURKB, RAC1, PPARGC1A, CDKN1A, CAV1, IL1B, and HSPD1 were identified as hub CRC DEGs statin targets. The genetic and molecular aspects of our findings reveal that statins might have a therapeutic effect on CRC.

Inappropriate Activation of TLR4/NF-κB is a Cause of Heart Failure

Significance: Heart failure, a disease with extremely high incidence, is closely associated with inflammation and oxidative stress. The Toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) pathway plays an important role in the occurrence and development of heart failure.

Recent advances: Previous studies have shown that TLR4/NF-κB causes heart failure by inducing oxidative stress and inflammation; damaging the endothelia; promoting fibrosis; and inducing myocardial hypertrophy, apoptosis, pyroptosis, and autophagy.

Critical issues: Understanding the pathogenesis of heart failure is essential for the treatment of this disease. In this review, we outline the mechanisms underlying TLR4/NF-κB pathway-mediated heart failure and discuss drugs that alleviate heart failure by regulating the TLR4/NF-κB pathway.

Future directions: During TLR4/NF-κB overactivation, interventions targeting specific receptor antagonists may effectively alleviate heart failure, thus providing a basis for the development of new anti-heart failure drugs.

Biological Actions, Implications, and Cautions of Statins Therapy in COVID-19

The Coronavirus Disease 2019 (COVID-19) showed worse prognosis and higher mortality in individuals with obesity. Dyslipidemia is a major link between obesity and COVID-19 severity. Statins as the most common lipid regulating drugs have shown favorable effects in various pathophysiological states. Importantly, accumulating observational studies have suggested that statin use is associated with reduced risk of progressing to severe illness and in-hospital death in COVID-19 patients. Possible explanations underlie these protective impacts include their abilities of reducing cholesterol, suppressing viral entry and replication, anti-inflammation and immunomodulatory effects, as well as anti-thrombosis and anti-oxidative properties. Despite these benefits, statin therapies have side effects that should be considered, such as elevated creatinine kinase, liver enzyme and serum glucose levels, which are already elevated in severe COVID-19. Concerns are also raised whether statins interfere with the efficacy of COVID-19 vaccines. Randomized controlled trials are being conducted worldwide to confirm the values of statin use for COVID-19 treatment. Generally, the results suggest no necessity to discontinue statin use, and no evidence suggesting interference between statins and COVID-19 vaccines. However, concomitant administration of statins and COVID-19 antiviral drug Paxlovid may increase statin exposure and the risk of adverse effects, because most statins are metabolized mainly through CYP3A4 which is potently inhibited by ritonavir, a major component of Paxlovid. Therefore, more clinical/preclinical studies are still warranted to understand the benefits, harms and mechanisms of statin use in the context of COVID-19.

All-cause mortality in COVID-19 patients receiving statin therapy: analysis of veterans affairs database cohort study

Statins have been advocated as a potential treatment for coronavirus disease-2019 (COVID-19) due to its pleotropic properties. The aim of the study was to elucidate the association between antecedent statin exposure and 30-day all-cause mortality, intensive care unit (ICU) admission and hypoxic respiratory failure requiring mechanical ventilation in patients diagnosed with COVID-19. Observational cohort study derived from the VA Corporate Data Warehouse of all veterans tested positive for COVID-19 between January 1st and May 31st, 2020. Antecedent use of statins was defined as a redeemed drug prescription in the 6 months prior to COVID-19 diagnosis. Propensity-matched mixed-effects logistic regression was performed, stratified by statin use. The study population comprised 14,268 patients with COVID-19 (median age 66 years (25th-75th percentile, 53-74), 90.7% men), of whom 7,168 were receiving a prescription for statins. Patients with statin exposure had a greater prevalence of comorbidities and a higher risk of mortality (Odd ratio [OR] 1.52; 95% confidence interval [CI] 1.37-1.68). After adjusting for covariates, statin exposure was not associated with a decreased mortality in the overall cohort by either Cox proportional hazards stratified model (HR 0.99; 95% CI 0.88-1.12) or propensity matching (HR .86; 95% CI 0.74-1.01). Similarly, there was no demonstrated advantage of statins in reducing the risk of ICU admission (HR 0.92; 95% CI 0.74-1.31) or hypoxic respiratory failure requiring mechanical ventilation (HR 1.02; 95% CI 0.81-1.29). Antecedent statin exposure in patients with COVID-19 was not associated with a decreased risk of 30-day all-cause mortality or need for mechanical ventilation.

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.

Perioperative Statin Use May Reduce Postoperative Arrhythmia Rates After Total Joint Arthroplasty

BACKGROUND

Postoperative arrhythmias are associated with increased morbidity and mortality in total joint arthroplasty (TJA) patients. HMG-CoA (3-hydroxy-3-methyl-glutaryl-CoA) reductase inhibitors (statins) decrease atrial fibrillation rates after cardiac surgery, but it is unknown if this cardioprotective effect is maintained after joint reconstruction surgery. We aim to determine if perioperative statin use decreases the incidence of 90-day postoperative arrhythmias in patients undergoing primary TJA.

METHODS

We performed a single-center retrospective cohort study in which 231 primary TJA patients (109 hips, 122 knees) received simvastatin 80 mg daily during their hospitalization as part of a single surgeon's standard postoperative protocol. This cohort was matched to 966 primary TJA patients (387 hips and 579 knees) that did not receive simvastatin. New-onset arrhythmias (bradycardia, atrial fibrillation/tachycardia/flutter, paroxysmal supraventricular tachycardia, and ventricular tachycardia) and complications (readmissions, thromboembolism, infection, and dislocation) within 90 days of the procedure were documented. Categorical variables were analyzed using Fisher's exact tests. Our study was powered to detect a 3% difference in arrhythmia rates.

RESULTS

Within 90 days postoperatively, arrhythmias occurred in 1 patient (0.4%) who received a perioperative statin, 39 patients (4.0%) who did not receive statins (P = .003), and 24 patients (4.2%) who were on outpatient statins (P = .005). This is 10-fold reduction in the relative risk of developing a postoperative arrhythmia within 90 days of arthroplasty and an absolute risk reduction of 3.6%.

CONCLUSION

Treating as few as 28 patients with perioperative simvastatin prevents one new cardiac arrhythmia within 90 days in statin-naïve patients undergoing TJA.

Plausible Positive Effects of Statins in COVID-19 Patient

Since the onset of the global COVID-19 pandemic, there has been much discussion about the advantages and disadvantages of ongoing chronic drug therapies in SARS-CoV-2-positive patients. These discussions include also statins treatment. The statins are among the most widely used drugs in the global population. Statins aim to lower cholesterol, which is essential for many biological processes but can lead to heart disease if levels are too high; however, also the pleiotropic effects of statins are well known. So could the anti-inflammatory or the potential antiviral effects of statins be helpful in avoiding extreme inflammation and severity in COVID-19? To date, there are conflicting opinions on the effects of statins in the course of COVID-19 infection. The aim of this article is to describe the molecular and pharmacological basis of the pleiotropic effects of statins that could be more involved in the fight against COVID-19 infection and to investigate the current epidemiological evidence in the literature on the current and important topic.

Prior Statin Use and Risk of Mortality and Severe Disease From Coronavirus Disease 2019: A Systematic Review and Meta-analysis

BACKGROUND

Statins up-regulate angiotensin-converting enzyme 2, the receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), while also exhibiting pleiotropic antiviral, antithrombotic, and anti-inflammatory properties. Uncertainties exist about their effect on the course of SARS-CoV-2 infection. We sought to systematically review the literature and perform a meta-analysis to examine the association between prior statin use and outcomes of patients with coronavirus disease 2019 (COVID-19).

METHODS

We searched Ovid Medline, Web of Science, Scopus, and the preprint server medRxiv from inception to December 2020. We assessed the quality of eligible studies with the Newcastle-Ottawa quality scale. We pooled adjusted relative risk (aRRs) of the association between prior statin use and outcomes of patients with COVID-19 using the DerSimonian-Laird random-effects model and assessed heterogeneity using the I 2 index.

RESULTS

Overall, 19 (16 cohorts and 3 case-control) studies were eligible, with a total of 395 513 patients. Sixteen of 19 studies had low or moderate risk of bias. Among 109 080 patients enrolled in 13 separate studies, prior statin use was associated with a lower risk of mortality (pooled aRR, 0.65 [95% confidence interval {CI}, .56-.77], I 2 = 84.1%) and a reduced risk of severe COVID-19 was also observed in 48 110 patients enrolled in 9 studies (pooled aRR, 0.73 [95% CI, .57-.94], I 2 = 82.8%), with no evidence of publication bias.

CONCLUSIONS

Cumulative evidence suggests that prior statin use is associated with lower risks of mortality or severe disease in patients with COVID-19. These data support the continued use of statins medications in patients with an indication for lipid-lowering therapy during the COVID-19 pandemic.

Cystic Fibrosis Lung Disease in the Aging Population

The demographics of the population with cystic fibrosis (CF) is continuously changing, with nowadays adults outnumbering children and a median predicted survival of over 40 years. This leads to the challenge of treating an aging CF population, while previous research has largely focused on pediatric and adolescent patients. Chronic inflammation is not only a hallmark of CF lung disease, but also of the aging process. However, very little is known about the effects of an accelerated aging pathology in CF lungs. Several chronic lung disease pathologies show signs of chronic inflammation with accelerated aging, also termed “inflammaging”; the most notable being chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). In these disease entities, accelerated aging has been implicated in the pathogenesis via interference with tissue repair mechanisms, alterations of the immune system leading to impaired defense against pulmonary infections and induction of a chronic pro-inflammatory state. In addition, CF lungs have been shown to exhibit increased expression of senescence markers. Sustained airway inflammation also leads to the degradation and increased turnover of cystic fibrosis transmembrane regulator (CFTR). This further reduces CFTR function and may prevent the novel CFTR modulator therapies from developing their full efficacy. Therefore, novel therapies targeting aging processes in CF lungs could be promising. This review summarizes the current research on CF in an aging population focusing on accelerated aging in the context of chronic airway inflammation and therapy implications.

The advantages of drug treatment with statins in patients with SARS-CoV-2 infection

On 11 March 2020 the World Health Organization (WHO) declared a status of global pandemic caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (coronavirus disease 2019, COVID-19). The pandemic is currently underway, and to date has caused approximately 2.42 million deaths worldwide. The first vaccines have recently been licensed; however, research continues to identify therapeutic agents to prevent serious complications, such as anti-inflammatory, immunomodulatory, anticoagulant or antiviral agents authorized for other therapeutic indications. Epidemiological evidence shows that advanced age and comorbidities, such as diabetes, heart disease, and dyslipidemia may represent COVID-19 risk factors. In particular, in patients with hypercholesterolemia treated with statins, it is recommended that treatment should not be discontinued if COVID-19 infection occurs. The pleiotropic effects of statins are well known. In this brief review, we propose that the use of statins can potentially protect against SARS-CoV-2-induced tissue damage and improve lung function in COVID-19 patients through several pleiotropic effects. Pleiotropic effects of statins that may be a significant benefit in patients with hypercholesterolemia treated with statins and COVID-19 positive. Recent evidence shows promising results.

Statins as an adjunctive therapy for COVID-19: the biological and clinical plausibility

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the coronavirus disease 2019 (COVID-19) has infected millions of individuals and has claimed hundreds of thousands of human lives worldwide. Patients with underlying cardiovascular conditions are at high risk for SARS-CoV-2 infection, and COVID-19 patients have high incidence of cardiovascular complications such as acute cardiac injury, arrhythmias, heart failure, and thromboembolism. The disease has no approved proven effective therapy and hence repurposing of existing approved drugs has been considered as the fastest treatment approach. Statins have been shown to exhibit lipid lowering dependent and independent cardiovascular protective effects as well as favorable effects in various other pathophysiological states. These beneficial properties of statins are a result of their multiple pleotropic effects that include, anti-inflammatory, immunomodulatory, antithrombotic and antimicrobial properties. In this review, we provide a comprehensive description of the mechanisms of the pleotropic effects of statins, the relevant pre-clinical and clinical data pertinent to their role in infections and acute lung injury, the possible cardiovascular benefits of statins in COVID-19, and the implications of the therapeutic potential of statins in COVID-19 disease. We conclude with the rationale for conducting randomized controlled trials of statins in COVID-19 disease.

Airway Redox Homeostasis and Inflammation Gone Awry: From Molecular Pathogenesis to Emerging Therapeutics in Respiratory Pathology

As aerobic organisms, we are continuously and throughout our lifetime subjected to an oxidizing atmosphere and, most often, to environmental threats. The lung is the internal organ most highly exposed to this milieu. Therefore, it has evolved to confront both oxidative stress induced by reactive oxygen species (ROS) and a variety of pollutants, pathogens, and allergens that promote inflammation and can harm the airways to different degrees. Indeed, an excess of ROS, generated intrinsically or from external sources, can imprint direct damage to key structural cell components (nucleic acids, sugars, lipids, and proteins) and indirectly perturb ROS-mediated signaling in lung epithelia, impairing its homeostasis. These early events complemented with efficient recognition of pathogen- or damage-associated recognition patterns by the airway resident cells alert the immune system, which mounts an inflammatory response to remove the hazards, including collateral dead cells and cellular debris, in an attempt to return to homeostatic conditions. Thus, any major or chronic dysregulation of the redox balance, the air-liquid interface, or defects in epithelial proteins impairing mucociliary clearance or other defense systems may lead to airway damage. Here, we review our understanding of the key role of oxidative stress and inflammation in respiratory pathology, and extensively report current and future trends in antioxidant and anti-inflammatory treatments focusing on the following major acute and chronic lung diseases: acute lung injury/respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and cystic fibrosis.

Anti-inflammatory Action of Statins in Cardiovascular Disease: the Role of Inflammasome and Toll-Like Receptor Pathways

Atherosclerosis is one type of cardiovascular disease (CVD) in which activation of the NLRP3 inflammasome and toll-like receptor (TLR) pathways is implicated. One of the most effective treatments for atherosclerosis is the use of statin medications. Recent studies have indicated that statins, in addition to their lipid-lowering effects, exert inhibitory and/or stimulatory effects on the NLRP3 inflammasome and TLRs. Some of the statins lead to activation of the inflammasome and subsequently cause secretion of IL-1β and IL-18. Thus, these actions may further aggravate the disease. On the other hand, some statins cause inhibition of the inflammasome or TLRs and along with lipid-lowering, help to improve the disease by reducing inflammation. In this article, we discuss these contradictory studies and the mechanisms of action of statins on the NLRP3 inflammasome and TLR pathways. The dose-dependent effects of statins on the NLRP3 complex are related to their chemistry, pharmacokinetic properties, and danger signals. Lipophilic statins have more pleiotropic effects on the NLRP3 complex in comparison to hydrophilic statins. Statins can suppress TLR4/MyD88/NF-ĸB signaling and cause an immune response shift to an anti-inflammatory response. Furthermore, statins inhibit the NF-ĸB pathway by decreasing the expression of TLRs 2 and 4. Statins are cost-effective drugs, which should have a continued future in the treatment of atherosclerosis due to both their immune-modulating and lipid-lowering effects.

Downregulation of PTEN by sodium orthovanadate protects the myocardium against ischemia/reperfusion injury after chronic atorvastatin treatment

Acute statin treatment has been reported to be critical in protecting the cardiac cells against ischemia/reperfusion injury by activating PI3K/Akt signal pathway. In vitro rat myocardial ischemia/reperfusion model, chronic statin treatment led to upregulation of phosphatase and tensin homolog (PTEN). This has been potentially indicated the correlation in PTEN and protective effect of statin on myocardium. In this current study, we evaluated the role of sodium orthovanadate a nonspecific inhibitor to PTEN and its correlation with atorvastatin on protecting myocardium against ischemia/reperfusion injury. We found a long-term statin treatment could increase the PTEN level, and this process was counteracted in the presence of sodium orthovanadate. However, the phosphotyrosine level was not affected by this statin. Besides, this process was mediated by Akt signaling since phosphorylated Akt level was altered by statin and sodium orthovanadate treatment. In a conclusion, this study showed a potential mechanism underlying PTEN-induced attenuation in long-term statin's therapeutic effect, which provided the new insight into the synergic role of PTEN and atorvastatin in protecting cardiac cells against ischemia/reperfusion injury.

Effect of statins on toll-like receptors: a new insight to pleiotropic effects

The toll-like receptors (TLRs) are a class of transmembrane-spanning receptors that are sentinels of both innate and adaptive immunity. Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) are the most commonly prescribed therapeutic agents for treating hypercholesterolemia globally. However, statin therapy appears to have pleiotropic effects including attenuation of chronic low-grade inflammation and modulation of TLR activity. Statins through abolition of TLR4 expression and regulation of the TLR4/Myd88/NF-κB signaling pathway may slow the progression of atherosclerosis and other inflammatory diseases. In this review, we have focused on the impact and mechanism of action of statins on cardiovascular and non-cardiovascular diseases.

In vitro and in vivo delivery of atorvastatin: A comparative study of anti-inflammatory activity of atorvastatin loaded copolymeric micelles

Statins have been shown to exert ‘pleiotropic effects’ independent of their cholesterol lowering actions that include anti-inflammatory properties. In this study we synthesized mono methoxy poly (ethylene glycol)–poly (ε-caprolactone) (mPEG-PCL) di block copolymers. The structure of the copolymers was characterized by H nuclear magnetic resonance, Fourier-transform infrared spectroscopy, differential scanning calorimetry and gel permeation chromatography techniques. In this method, atorvastatin was encapsulated within micelles through a single-step nano-precipitation method, leading to the formation of atorvastatin-loaded mPEG-PCL (atorvastatin/mPEG-PCL) micelles. The resulting micelles were characterized further by various techniques such as dynamic light scattering and atomic force microscopy. In this study the anti-inflammatory activity of atorvastatin and atorvastatin/mPEG-PCL micelles on acute models of inflammation are analyzed, to compare the effect of indometacin in rats. Carrageenan induces rat paw edema; six animals of each group (10 groups) received indometacin, atorvastatin, and atorvastatin/mPEG-PCL micelles orally 1, 6, 12 and 24 h before carrageenan injection in paw. The paw edema thickness measured at 1, 2, 3 and 4 h after injection and percentage inhibition of edema in various groups were calculated. The results showed that the zeta potential of micelles was about −16.6 mV and the average size was 81.7 nm. Atorvastatin was encapsulated into mPEG-PCL micelles with loading capacity of 14.60 ± 0.96% and encapsulation efficiency of 62.50 ± 0.84%. Atorvastatin and atorvastatin/mPEG-PCL micelles showed significant anti-inflammatory activity in the present study. The anti-inflammatory activity of atorvastatin and atorvastatin/mPEG-PCL micelles was significant in comparison with indometacin. Atorvastatin/mPEG-PCL micelles showed more anti-inflammatory activity than atorvastatin. This study revealed the anti-inflammatory activity of atorvastatin and atorvastatin/mPEG-PCL micelles and suggested the statins have a potential inflammatory activity along with its lipid lowering properties. Contrary to anti-inflammatory effects, the pro-inflammatory responses are independent of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibition and can be mediated directly by atorvastatin.

Fecal microbiota transplantation in metabolic syndrome: History, present and future

The history of fecal microbiota transplantation (FMT) dates back even to ancient China. Recently, scientific studies have been looking into FMT as a promising treatment of various diseases, while in the process teaching us about the interaction between the human host and its resident microbial communities. Current research focuses mainly on Clostridium difficile infections, however interest is rising in other areas such as inflammatory bowel disease (IBD) and the metabolic syndrome. With regard to the latter, the intestinal microbiota might be causally related to the progression of insulin resistance and diabetes. FMT in metabolic syndrome has proven to be an intriguing method to study the role of the gut microbiota and open the way to new therapies by dissecting in whom insulin resistance is driven by microbiota. In this article we review the history of FMT, the present evidence on its role in the pathophysiology of metabolic syndrome and its efficacy, limitations and future prospects.

Analysis of Bone Repair and Inflammatory Process Caused by Simvastatin Combined With PLGA+HA+βTCP Scaffold

PURPOSE

This study evaluated the tissue and inflammatory responses to the use of simvastatin and poly(lactic-co-glycolic acid) + hydroxyapatite + β-tricalcium phosphate (PLGA+HA+βTCP) scaffold for bone repair.

MATERIALS AND METHODS

Two defects of 5 mm in diameter were made in the calvaria of rats, which were shared into the following 6 groups: naive, sham, vehicle, PLGA+HA+βTCP scaffold, simvastatin (4 mg/mL), and simvastatin with the scaffold. Tissue samples were collected at 1, 7, 15, 30, and 60 days after surgery. Inflammation was evaluated by interleukin-1 beta and tumor necrosis factor alpha quantification and by a hemogram, whereas bone repair was evaluated using densitometry and scanning electron microscopy. Data were statistically analyzed using ANOVA followed by post hoc tests (P < 0.05).

RESULTS

There was an increased cytokine expression in the scaffold and simvastatin groups (P < 0.001 and P < 0.05, respectively) 1 day after surgery but no alterations on the hemogram were observed. It was found on bone tissue samples that 60 days after surgery all groups presented similar densitometry values and morphology characteristics, despite the occurrence of bone formation delay in the simvastatin group (P < 0.01).

CONCLUSION

The use of simvastatin and PLGA+HA+βTCP scaffold, associated or not, did not lead to improvement in bone repair.

Differential Effects of Peroxisome Proliferator Activator Receptor-α and γ Ligands on Intimal Hyperplasia After Balloon Catheter-Induced Vascular Injury in Zucker Rats

Background: Patients with type 2 diabetes mellitus have a higher rate of restenosis following angioplasty. Peroxisome proliferator activator receptor-x (PPAR) and y ligands such as fenofibrate and rosiglitazone, respectively, have been shown to have protective effects on the vessel wall. We studied the effect of fenofibrate and rosiglitazone on intimal hyperplasia in the Zucker rat, a model for insulin resistance and type 2 diabetes mellitus, following balloon catheter-induced injury.

Methods and Results: Three groups of 13-week-old female fatty Zucker rats were administered an aqueous suspension of either 3 mg/kg/d rosiglitazone (n = 7) or 150 mg/kg/d fenofibrate (n = 6) by gavage, or served as controls (n = 9). In addition, two groups of 13-week-old female lean Zucker rats were either administered 3 mg/kg/d rosiglitazone (n = 6) or served as controls (n = 6). Carotid balloon injury was induced 1 week after the drugs were started. The drug administration was continued for 3 weeks. A 2-mm balloon catheter was introduced through the femoral artery to the left carotid. The balloon was inflated to 4 atmospheres for 20 seconds and then was deflated to 2 atmospheres and dragged down to the aorta. The rats were killed 3 weeks after the injury. The carotid intima/media ratio was calculated. Intimal hyperplasia after carotid balloon-induced injury in the fatty Zucker rats was significantly reduced in the group treated with rosiglitazone (0.18 ± 0.29) compared with the untreated group (0.97 ± 0.13; P < .01). Plasma glucose, triglyceride, and insulin levels were elevated, indicative of the presence of insulin resistance; rosiglitazone treatment significantly reduced insulin and triglyceride levels without decreasing glucose. Rosiglitazone treatment also reduced, but to a lesser extent, the intimal hyperplasia in the lean Zucker rats (0.57 ± 0.10 vs 1.06 ± 0.12 treated and untreated, respectively; P < .01); however, it had no effect on insulin, triglyceride, or glucose levels in this group. The intimal hyperplasia in the fatty Zucker rats treated with fenofibrate was not reduced compared with controls (0.84 ± 0.26 vs 0.97 ± 0.13, respectively); fenofibrate reduced insulin and triglyceride, but not glucose levels, in these animals.

Conclusions: The PPAR-y ligand rosiglitazone, but not the PPAR-x ligand fenofibrate, decreases intimal hyperplasia following balloon injury in both fatty and lean Zucker rats. This effect of the PPAR-y ligand was independent of glycemia, insulin, and lipid levels, and was more pronounced in insulin-resistant rats.

Pleiotropic effects of statins: new therapeutic targets in drug design

The HMG Co-enzyme inhibitors and new lipid-modifying agents expand their new therapeutic target options in the field of medical profession. Statins have been described as the most effective class of drugs to reduce serum cholesterol levels. Since the discovery of the first statin nearly 30 years ago, these drugs have become the main therapeutic approach to lower cholesterol levels. The present scientific research demonstrates numerous non-lipid modifiable effects of statins termed as pleiotropic effects of statins, which could be beneficial for the treatment of various devastating disorders. The most important positive effects of statins are anti-inflammatory, anti-proliferative, antioxidant, immunomodulatory, neuroprotective, anti-diabetes, and antithrombotic, improving endothelial dysfunction and attenuating vascular remodeling besides many others which are discussed under the scope of this review. In particular, inhibition of Rho and its downstream target, Rho-associated coiled-coil-containing protein kinase (ROCK), and their agonistic action on peroxisome proliferator-activated receptors (PPARs) can be viewed as the principle mechanisms underlying the pleiotropic effects of statins. With gradually increasing knowledge of new therapeutic targets of statins, their use has also been advocated in chronic inflammatory disorders for example rheumatoid arthritis (RA) and in systemic lupus erythematosus (SLE). In the scope of review, we highlight statins and their pleiotropic effects with reference to their harmful and beneficial effects as a novel approach for their use in the treatment of devastating disorders. Graphical abstract Pleiotropic effect of statins.

Effects of simvastatin and taurine on delayed cerebral vasospasm following subarachnoid hemorrhage in rabbits

The aim of the current study was to observe the effects of simvastatin and taurine on delayed cerebral vasospasm (DCVS) following experimental subarachnoid hemorrhage (SAH) in rabbits. A total of 48 New Zealand white rabbits were allocated at random into four groups (control, SAH, SAH + simvastatin and SAH + taurine groups; n=12 each). The rabbit model of DCVS was established using a double hemorrhage method, which involved injecting autologous arterial blood into the cisterna magna in the SAH groups. The SAH + simvastatin group was administered oral simvastatin (5 mg/kg) daily between days 0-6. The SAH + taurine group was administered oral taurine (50 mg/kg) daily between days 0-6. Starch (50 mg/kg) was administered orally to the animals in the other two groups (control and SAH groups). The control group were not subjected to any other injections or treatment. The internal diameter and internal diameter/wall thickness of the basilar artery (BA) were measured. The expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were determined using immunohistochemical and quantitative polymerase chain reaction methods following the sacrifice of all animals on day 7. The activity of nuclear factor (NF)-κB in the BA was also measured using an electrophoretic mobility shift assay. The BA walls in the SAH + simvastatin and SAH + taurine groups exhibited reduced narrowing and corrugation of the tunica elastica interna compared with the SAH group. At the protein and cDNA levels, it was found that cerebral vasospasm of the BA in the SAH + simvastatin and SAH + taurine groups was alleviated, as indicated by the reduced expression of TNF-α, IL-1β, IL-6 and NF-κB compared with the SAH group (P<0.05). In conclusion, simvastatin and taurine reduced DCVS following SAH in rabbits, which suggests that these compounds may exert anti-inflammatory effects.

Simvastatin Inhibits Toll-like Receptor 8 (TLR8) Signaling in Primary Human Monocytes and Spontaneous Tumor Necrosis Factor Production from Rheumatoid Synovial Membrane Cultures

Simvastatin has been shown to have antiinflammatory effects that are independent of its serum cholesterol lowering action, but the mechanisms by which these antiinflammatory effects are mediated have not been elucidated. To explore the mechanism involved, the effect of simvastatin on toll-like receptor (TLR) signaling in primary human monocytes was investigated. A short pretreatment with simvastatin dose-dependently inhibited the production of tumor necrosis factor (TNF)-α in response to TLR8 activation (but not TLR2, -4 or -5). Statins are known inhibitors of the cholesterol biosynthetic pathway, but, intriguingly, TLR8 inhibition could not be reversed by addition of mevalonate or geranylgeranyl pyrophosphate, downstream products of cholesterol biosynthesis. TLR8 signaling was examined in HEK 293 cells stably expressing TLR8, where simvastatin inhibited I kappa B kinase (IKK)α/β phosphorylation and subsequent nuclear factor (NF)-κB activation without affecting the pathway to activating protein-1 (AP-1). Because simvastatin has been reported to have antiinflammatory effects in RA patients and TLR8 signaling contributes to TNF production in human RA synovial tissue in culture, simvastatin was tested in these cultures. Simvastatin significantly inhibited the spontaneous release of TNF in this model, which was not reversed by mevalonate. Together, these results demonstrate a hitherto unrecognized mechanism of simvastatin inhibition of TLR8 signaling that may in part explain its beneficial antiinflammatory effects.

Discovering functional modules by topic modeling RNA-Seq based toxicogenomic data

Toxicogenomics (TGx) endeavors to elucidate the underlying molecular mechanisms through exploring gene expression profiles in response to toxic substances. Recently, RNA-Seq is increasingly regarded as a more powerful alternative to microarrays in TGx studies. However, realizing RNA-Seq's full potential requires novel approaches to extracting information from the complex TGx data. Considering read counts as the number of times a word occurs in a document, gene expression profiles from RNA-Seq are analogous to a word by document matrix used in text mining. Topic modeling aiming at to discover the latent structures in text corpora would be helpful to explore RNA-Seq based TGx data. In this study, topic modeling was applied on a typical RNA-Seq based TGx data set to discover hidden functional modules. The RNA-Seq based gene expression profiles were transformed into "documents", on which latent Dirichlet allocation (LDA) was used to build a topic model. We found samples treated by the compounds with the same modes of actions (MoAs) could be clustered based on topic similarities. The topic most relevant to each cluster was identified as a "marker" topic, which was interpreted by gene enrichment analysis with MoAs then confirmed by compound and pathways associations mined from literature. To further validate the "marker" topics, we tested topic transferability from RNA-Seq to microarrays. The RNA-Seq based gene expression profile of a topic specifically associated with peroxisome proliferator-activated receptors (PPAR) signaling pathway was used to query samples with similar expression profiles in two different microarray data sets, yielding accuracy of about 85%. This proof-of-concept study demonstrates the applicability of topic modeling to discover functional modules in RNA-Seq data and suggests a valuable computational tool for leveraging information within TGx data in RNA-Seq era.

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

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

Atorvastatin improves plaque stability in ApoE-knockout mice by regulating chemokines and chemokine receptors

It is well documented that statins protect atherosclerotic patients from inflammatory changes and plaque instability in coronary arteries. However, the underlying mechanisms are not fully understood. Using a previously established mouse model for vulnerable atherosclerotic plaque, we investigated the effect of atorvastatin (10 mg/kg/day) on plaque morphology. Atorvastatin did not lower plasma total cholesterol levels or affect plaque progression at this dosage; however, vulnerable plaque numbers were significantly reduced in the atorvastatin-treated group compared to control. Detailed examinations revealed that atorvastatin significantly decreased macrophage infiltration and subendothelial lipid deposition, reduced intimal collagen content, and elevated collagenase activity and expression of matrix metalloproteinases (MMPs). Because vascular inflammation is largely driven by changes in monocyte/macrophage numbers in the vessel wall, we speculated that the anti-inflammatory effect of atorvastatin may partially result from decreased monocyte recruitment to the endothelium. Further experiments showed that atorvastatin downregulated expression of the chemokines monocyte chemoattractant protein (MCP)-1, chemokine (C-X3-C motif) ligand 1 (CX3CL1) and their receptors CCR2 and, CX3CR1, which are mainly responsible for monocyte recruitment. In addition, levels of the plasma inflammatory markers C-reactive protein (CRP) and tumor necrosis factor (TNF)-α were also significantly decrease in atorvastatin-treated mice. Collectively, our results demonstrate that atorvastatin can improve plaque stability in mice independent of plasma cholesterol levels. Given the profound inhibition of macrophage infiltration into atherosclerotic plaques, we propose that statins may partly exert protective effects by modulating levels of chemokines and their receptors. These findings elucidate yet another atheroprotective mechanism of statins.

Statins as regulators of redox state in the vascular endothelium: beyond lipid lowering

SIGNIFICANCE

Endothelial dysfunction and the imbalance between nitric oxide (NO) and reactive oxygen species production in the vascular endothelium are important early steps in atherogenesis, a major socioeconomic health problem. Statins have well-established roles in primary and secondary prevention of cardiovascular disease (CVD), due to both their lipid-lowering capacity and their pleiotropic properties. It is therefore important to understand the mechanisms by which statins can modify endothelial function and affect atherogenesis.

RECENT ADVANCES

In the last decade, the concept of statin pleiotropy has been reinforced by a large number of cell culture, animal, and translational studies. Statins have been shown to suppress the activity of pro-oxidant enzymes (such as NADPH oxidase) and pro-inflammatory transcriptional pathways in the endothelium. At the same time, they enhance endothelial NO synthase expression and activity while they also improve its enzymatic coupling. This leads to increased NO bioavailability and improved endothelial function.

CRITICAL ISSUES

Despite significant recent advances, the exact mechanisms of statin pleitropy are still only partially understood. The vast majority of the published literature relies on animal studies, while the actual mechanistic studies in humans are limited.

FUTURE DIRECTIONS

The success of statins as endothelium redox-modifying agents with a direct impact on clinical outcome highlights the importance of the endothelium as a therapeutic target in CVD. Better understanding of the mechanisms that underlie endothelial dysfunction could lead to the design of novel therapeutic strategies that target the vascular endothelium for the prevention and treatment of CVD.

Kmup-1 Protects Kidney from Streptozotocin-Induced Pro-Inflammation in Early Diabetic Nephropathy by Restoring Enos/Pparγ and Inhibiting MMP-9

KMUP-1 increases nitric oxide (NO) via endothelium nitric-oxide synthase (eNOS). Deficiency of eNOS and peroxisome proliferator-activated receptor-γ (PPARγ) is the pathogenesis of diabetic nephropathy (DN). This study aims to investigate whether KMUP-1 inhibits streptozotocin (STZ)-induced proinflammation in early DN. In experiments, STZ was used to induce diabetes in Wistar rats. Twenty-four male rats were randomly divided into four groups, including control, STZ (65 mg/kg, i.p.), STZ+KMUP-1(1 mg/kg) and STZ+KMUP-1 (2.5 mg/kg). KMUP-1 HCl was dissolved in distilled water for oral administration. The morphology of renal tissues was evaluated by periodic acid-schiff (PAS) staining and immunohistochemistry of eNOS. The expressions of matrix metalloproteinase-2/-9 (MMP-2/-9), eNOS, B-cell lymphoma 2 (Bcl-2), Bcl-2– associated X protein (Bax) and PPARγ of renal tissues were examined by Western blotting technique. NO production was evaluated by Griess reagent. Oxidative stress was evaluated by measuring reactive oxygen species (ROS). Results indicated that STZ-induced diabetic mellitus (DM) and subsequent DN, including excessive deposition of extracellular matrix (ECM) accompanied by enhanced MMP-2/-9, raised ROS production, increased Bcl-2/Bax ratio and decreased eNOS/PPARy over a period of 4 weeks. KMUP-1 inhibited STZ-induced hyperglycemia, BUN, MMP-2/MMP-9, and restored eNOS-PPARγ expression in renal tissues. Immunohistochemistry (IHC) of eNOS in glomeruli of renal cortical tissue sections indicated that KMUP-1 restored the eNOS caused by STZ. PAS staining of glomeruli indicated that KMUP-1 could not significantly reduce STZ-induced ECM expansion. Moreover, KMUP-1 increased Bcl-2/Bax and decreased ROS. In summary, KMUP-1 inhibits STZ-induced proinflammation in early DN by restoring PPARγ/eNOS and inhibiting MMP-9.

Antibiotic and anti-inflammatory therapies for cystic fibrosis

Cystic fibrosis (CF) lung disease is characterized by chronic bacterial infection and an unremitting inflammatory response, which are responsible for most of CF morbidity and mortality. The median expected survival has increased from <6 mo in 1940 to >38 yr now. This dramatic improvement, although not great enough, is due to the development of therapies directed at secondary disease pathologies, especially antibiotics. The importance of developing treatments directed against the vigorous inflammatory response was realized in the 1990s. New therapies directed toward the basic defect are now visible on the horizon. However, the impact of these drugs on downstream pathological consequences is unknown. It is likely that antibiotics and anti-inflammatory drugs will remain an important part of the maintenance regimen for CF in the foreseeable future. Current and future antibiotic and anti-inflammatory therapies for CF are reviewed.

Lifestyle factors and inflammation: associations by body mass index

Chronic inflammation, which is associated with obesity, may play a role in the etiology of several diseases. Thus, reducing inflammation may offer a disease-prevention strategy, particularly among the obese. Several modifiable factors have been associated with inflammation, including: dietary fiber intake, saturated fat intake, physical activity, smoking, alcohol, and use of certain supplements and medications (glucosamine, chondroitin, fish oil, vitamin E, statins and aspirin). To study whether these associations differ by body mass index (BMI), we used data on 9,895 adults included in the 1999-2004 cycles of the National Health and Nutrition Examination Survey (NHANES). Survey-weighted linear regression was used to evaluate the associations between modifiable factors and serum high-sensitivity C-reactive protein (hsCRP) concentrations across the following groups: underweight/normal weight (BMI<25 kg/m(2)), overweight (25-<30 kg/m(2)) and obese (30+ kg/m(2)). While several factors were significantly associated with decreased hsCRP among the normal weight or overweight groups (increased fiber intake, lower saturated fat intake, physical activity, not smoking, and use of chondroitin, fish oil and statins), only increasing dietary fiber intake and moderate alcohol consumption were associated with reduced hsCRP among the obese. Effect modification by BMI was statistically significant for the saturated fat-hsCRP and smoking-hsCRP associations. These results suggest that posited anti-inflammatory drugs and behaviors may be less strongly associated with inflammation among the obese than among lower weight persons.

Lipid nephrotoxicity: new concept for an old disease

The prevalence of obesity in the United States remains high, exceeding 30% in most states. As this trend continues unhindered, we will continue see a persistent rise in obesity-related metabolic effects—hypertension, dyslipidemia, diabetes mellitus, and atherosclerosis. These diseases are also the leading causes of chronic kidney diseases and end-stage renal disease. The lipid nephrotoxicity hypothesis, proposed over three decades ago, suggested that proteinuria, decreased albumin levels, and the resultant hyperlipidemia may cause a glomerulosclerosis similar to atherosclerosis. More recent studies have demonstrated the role of oxidized high-density lipoprotein (HDL) and low-density lipoprotein (LDL) particles in the progression of kidney disease. Elucidation of the role of lipid-lowering therapies and the concomitant improvement in tubulointerstitial and glomerular diseases is a further evidence of the role of lipids in renal injury. Synergistic effects of lipid-lowering drugs and blockers of the renin-angiotensin-aldosterone system (RAAS) in renal protection have also been documented. Dyslipidemia in renal disease is usually characterized by elevated LDL cholesterol, low HDL cholesterol, and high triglycerides. After an initial glomerular injury, likely to be inflammatory, a series of self-perpetuating events occur. Increased glomerular basement permeability leads to loss of lipoprotein lipase activators, which results in hyperlipidemia. Circulating LDL has a charge affinity for glycoaminoglycans in the glomerular basement membrane and further increases its permeability. Substantial amounts of filtered lipoprotein cause proliferation of mesangial cells. Proximal tubules reabsorb some of the filtered lipoprotein, and the remainder is altered during passage through the nephron. If intraluminal pH is close to the isoelectric point of the apoprotein, luminal apoprotein will precipitate, causing tubulointerstitial disease. This review shows the evidence for the role of lipids in development of chronic renal disease, the pathophysiology of lipid nephrotoxicity, and strategies available to clinicians to slow the progression of disease.

Prospective study of statin use and risk of Parkinson disease

OBJECTIVE

To prospectively examine whether use of statins is associated with altered risk of Parkinson disease (PD).

DESIGN, SETTING, AND PARTICIPANTS

A prospective study including 38 192 men and 90 874 women participating in 2 ongoing US cohorts, the Health Professional Follow-up Study and the Nurses' Health Study, was conducted. Information on regular cholesterol-lowering drug use (≥2 times/wk) was collected in 1994 in both cohorts via questionnaire. Relative risks (RRs) and 95% CIs were computed using Cox proportional hazards models adjusting for age, smoking, caffeine intake, duration of hypercholesterolemia, and other covariates.

MAIN OUTCOME MEASURE

Incident PD.

RESULTS

During 12 years of follow-up (1994-2006), we documented 644 incident PD cases (338 women and 306 men). The risk of PD was lower among current statin users (adjusted pooled RR = 0.74; 95% CI, 0.54-1.00; P = .049) relative to nonusers. A significant association was observed in participants younger than 60 years at baseline (adjusted pooled RR = 0.31; 95% CI, 0.11-0.86; P = .02) but not among those who were older (adjusted pooled RR = 0.83; 95% CI, 0.60-1.14; P = .25) (P for interaction = .03).

CONCLUSIONS

We found that regular use of statins was associated with a modest reduction in PD risk. The possibility that some statins may reduce PD risk deserves further consideration.

Interplay between statins and PPARs in improving cardiovascular outcomes: a double-edged sword?

Statins are best-selling medications in the management of high cholesterol and associated cardiovascular complications. They inhibit 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA)-reductase in order to prevent disproportionate cholesterol synthesis. Statins slow the progression of atherosclerosis, prevent the secondary cardiovascular events and improve the cardiovascular outcomes in patients with elevated cholesterol levels. The underlying mechanisms pertaining to the cardioprotective role of statins are linked with numerous pleiotropic actions including inhibition of inflammatory events and improvement of endothelial function, besides an effective cholesterol-lowering ability. Intriguingly, recent studies suggest possible interplay between statins and nuclear transcription factors like PPARs, which should also be taken into consideration while analysing the potential of statins in the management of cardiovascular complications. It could be suggested that statins have two major roles: (i) a well-established cholesterol-lowering effect through inhibition of HMG-CoA-reductase; (ii) a newly explored PPAR-activating property, which could mediate most of cardiovascular protective pleiotropic effects of statins including anti-inflammatory, antioxidant and anti-fibrotic properties. The present review addressed the underlying principles pertaining to the modulatory role of statins on PPARs.

Statins inhibit monocyte chemotactic protein 1 expression in endometriosis

Statins are potent inhibitors of the endogenous mevalonate pathway. Besides inhibiting cholesterol biosynthesis, statins may also demonstrate anti-inflammatory properties. Inflammation is implicated in the attachment and invasion of endometrial cells to the peritoneal surface and growth of ectopic endometrium by inducing proliferation and angiogenesis. In this study, the effect of statins on monocyte chemotactic protein 1 (MCP-1) expression in endometriotic implants in nude mouse model and in cultured endometriotic cells was evaluated. In mouse model, simvastatin decreased MCP-1 expression in a dose-dependent manner in endometriotic implants (P < .05). Similarly, both simvastatin and mevastatin revealed a dose-dependent inhibition of MCP-1 production in cultured endometriotic cells (P < .01). This inhibitory effect of the statins on MCP-1 production was reversed by the downstream substrates of the mevalonate pathway. Moreover, statins decreased MCP-1 messenger RNA expression in cultured endometriotic cells (P < .05). In conclusion, statins exert anti-inflammatory effect in endometriotic cells and could provide a potential treatment of endometriosis in the future.

Toll-like receptors and diabetes: a therapeutic perspective

Diabetes is a mutifactorial metabolic disorder that leads to a number of complications. Diabetes is estimated to affect 36 million people in the U.S.A., and the prevalence of diagnosed and undiagnosed diabetes is at 9.3% and continues to rise. Evidence from experimental animal models as well as humans has indicated that systemic inflammation plays a role in the pathophysiological processes of diabetes and is facilitated by innate immune responses. TLRs (Toll-like receptors) are key innate immune receptors that recognize conserved PAMPs (pathogen-associated molecular patterns), induce inflammatory responses essential for host defences and initiate an adaptive immune response. Although TLR expression is increased in a plethora of inflammatory disorders, the effects of metabolic aberrations on TLRs and their role in diabetes and its complications is still emerging. In the present paper, we provide a systematic review on how TLRs play a detrimental role in the pathogenic processes [increased blood sugar, NEFAs (non-esterified 'free' fatty acids), cytokines and ROS (reactive oxygen species)] that manifest diabetes. Furthermore, we will highlight some of the therapeutic strategies targeted at decreasing TLRs to abrogate inflammation in diabetes that may eventually result in decreased complications.

PPARγ in coronary atherosclerosis: in vivo expression pattern and correlations with hyperlipidemic status and statin treatment

OBJECTIVE

Peroxisome proliferator-activated receptor-γ (PPARγ) is involved in regulation of macrophage inflammation and in atherosclerosis. Herein we investigate the influence of statin treatment on PPARγ expression in coronary artery disease.

METHOD

PPARγ expression was investigated in coronary atherosclerotic atherectomies (N=48) and arteries (N=12) from patients with stable or unstable coronary syndromes or undergoing cardiac transplantation for end-stage ischemic cardiomyopathy, respectively, by immunohistochemistry. Plaque components and tissue factor immunoreactivity were also investigated. Atherectomies were obtained from de novo culprit lesions of hypercholesterolemic (16 statin-treated and 16 untreated) and normolipidemic (N=16) patients. Furthermore, PPARγ expression was evaluated in patients peripheral blood monocytes and in monocytic U937 cells after atorvastatin incubation, by Western blot analysis.

RESULT

PPARγ expression was higher in coronary plaques and peripheral blood monocytes of statin-treated patients, and it significantly increased in monocytes after 24h atorvastatin incubation (p<0.05). Intra-plaque macrophage content, atheroma, neoangiogenesis and hemorrhage, and circulating CRP levels were lower in statin-treated than untreated hypercholesterolemic patients and comparable with normolipidemic subjects. PPARγ immunoreactivity was localized to neointima and media, its distribution pattern being different from that of tissue factor.

CONCLUSION

PPARγ expression was enhanced in statin-treated patients with different distribution and behavior as compared to atheroma, macrophage content, tissue factor immunoreactivity and serum CRP. In vitro studies showed increased PPARγ expression in monocytes after atorvastatin incubation. These findings provide further evidence as to the protective role of statins in coronary artery disease and their influence on PPARγ expression in coronary plaques and on the inflammatory status of patients.

Rosuvastatin reduces microglia in the brain of wild type and ApoE knockout mice on a high cholesterol diet; implications for prevention of stroke and AD

We have previously shown that a high cholesterol (HC) diet results in increases in microglia load and levels of the pro-inflammatory cytokine interleukin-6 (IL-6) in the brains of wild type (WT) and apolipoprotein E knockout (ApoE-/-) mice. In the present investigation, we analyzed whether treatment with rosuvastatin, an inhibitor of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, would prevent the increases in inflammatory microglia and IL-6 levels in the brain and plasma of WT and ApoE-/- mice. We report that a HC diet resulted in an increased microglia load in the brains of WT and ApoE-/- mice, in support of our previous study. Treatment with rosuvastatin significantly decreased the microglia load in the brains of WT and ApoE-/- mice on a HC diet. Rosuvastatin treatment resulted in lowered plasma IL-6 levels in WT mice on a HC diet. However, in the present study the number of IL-6 positive cells in the brain was not significantly affected by a HC diet. A recent clinical study has shown that rosuvastatin reduces risk of ischemic stroke in patients with high plasma levels of the inflammatory marker C-reactive protein by 50%. The results from our study show that rosuvastatin reduces inflammatory cells in the brain. This finding is essential for furthering the prevention and treatment of neurodegenerative diseases such as Alzheimer's disease (AD) and stroke.

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.

An update on the lipid nephrotoxicity hypothesis

When the 'lipid nephrotoxicity hypothesis' was proposed in 1982, it brought together several disparate experimental findings in hyperlipidemia and renal disease to suggest that concomitant hyperlipidemia and proteinuria would cause self-perpetuating renal disease once the initial glomerular insult was no longer present. This process would be analogous to atherosclerosis. Since 1982, increasing evidence has supported the hypothesis that lipid abnormalities contribute to both atherosclerosis and glomerulosclerosis. In this Review, we discuss research developments that are relevant to the lipid nephrotoxicity hypothesis. We describe how inflammatory stress accompanying chronic kidney disease modifies lipid homeostasis by increasing cholesterol uptake mediated by lipoprotein receptors, inhibiting cholesterol efflux mediated by the ATP-binding cassette transporter 1 and impairing cholesterol synthesis in peripheral cells. As a result of these events, cholesterol relocates to and accumulates in renal, vascular, hepatic and possibly other tissues. The combination of increased cellular cholesterol influx and reduced efflux causes injury in some tissues and lowers the plasma cholesterol level. In addition, inflammatory stress causes a degree of statin resistance via unknown mechanisms. These phenomena alter traditional understanding of the pathogenesis of lipid-mediated renal and vascular injury and could influence the clinical evaluation of renal and cardiovascular risk and the role of lipid-lowering treatment in affected patients.

Toll like receptor 4 in atherosclerosis and plaque destabilization

The immune system plays a pivotal role in initiation and progression of atherosclerosis. Monocytes and T-lymphocytes are the first cells to enter the damaged endothelium. Differentiation of monocytes into macrophages and ingestion of lipids by these macrophages turning them into foam cells is a crucial step in the development of a fatty streak, the first sign of atherosclerosis. In recent years there has been accumulating evidence for the involvement of Toll like receptor 4, a pattern recognition receptor of the innate immune system, in the pathogenesis of atherosclerosis. Different cell types present in the atherosclerotic plaque express TLR4 and several pro-atherogenic ligands have been shown to activate TLR4. The innate immune system and the TLR signaling cascade may play an important role not only in the pathogenesis of atherosclerosis, but also in plaque destabilization. In this review, we discuss the role of TLR4 in the pathogenesis of atherosclerosis and vulnerable plaque development.