Statins, inflammation, and sepsis: hypothesis

Statins do not improve short-term survival in an oriental population with sepsis

OBJECTIVES

The aim of this study was to define the effect of statin on 30-day mortality in an oriental population with sepsis.

DESIGN

We conducted a retrospective study on patients with sepsis at National Taiwan University Hospital from 2001 to 2002. The effects of statins on 30-day mortality were evaluated based on clinical settings. Log-rank test and Cox regression analysis were performed using the proportional hazards assumption.

RESULTS

A total of 763 episodes of sepsis were reviewed; 454 consecutive patients were considered eligible. Among them, 104 (22.9%) took a statin at least 30 days before admission and during sepsis course, whereas the other 350 control (77.1%) did not. There was no significant difference of 30-day sepsis-related mortality between groups (19.2% vs 18.9%, P = .952). Statin treatment was not associated with decreased mortality at 30 days (P = .853; risk ratio, 0.95; 95% confidence interval, 0.53-1.68).

CONCLUSION

Short-term, sepsis-related mortality in a septic Taiwanese population was not reduced with statin treatment in our study. We concluded that statin therapy may have little effect on the survival of sepsis in oriental people, particularly in Taiwanese.

Statin therapy: not just used to lower cholesterol?

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, also known as statins, are the cornerstones of treatment of hyperlipidemia. They are widely used drugs that have well-documented, advantageous effects on cholesterol and atherosclerosis. The pleiotropic activities of statins can lead to newer applications. This review describes some of the available evidence supporting the use of statins for the treatment of acute coronary syndrome, as adjuncts to percutaneous coronary intervention, and for the prevention of sepsis. It also briefly discusses the rationale behind the potential development of statin-eluting stents.

Statins and sepsis: multiple modifications at multiple levels

Sepsis, an infection-induced inflammatory syndrome, is a leading and increasing cause of mortality worldwide. Animal and human observational studies suggest statins may prevent the morbidity and mortality associated with the sepsis syndrome. In this Review, we describe the demonstrated mechanisms through which statins modulate the inflammatory response associated with sepsis. These mechanisms include effects on cell signalling with consequent changes at the transcriptional level, the induction of haem oxygenase, the direct alteration of leucocyte-endothelial cell interaction, and the reduced expression of MHC II. Since statins do not target individual inflammatory mediators, but possibly reduce the overall magnitude of the systemic response, this effect could prove an important distinguishing feature modulating the host response to septic insults. This work establishes the biological plausibility needed for future trials of statins in critical illness.

The effect of statin therapy on infection-related mortality in patients with atherosclerotic diseases

OBJECTIVE

Statins have pleiotropic effects that are independent of their lipid-lowering ability. We have previously shown that prior statin therapy is associated with a decreased risk of severe sepsis in patients admitted with acute bacterial infection. The aim of this study was to determine whether statin therapy is associated with a decreased risk of infection-related mortality.

DESIGN

A prospective, observational, population-based study.

SETTING

Tertiary university medical center.

PATIENTS

Using a computerized database, 11,490 patients with atherosclerotic diseases were identified and followed for up to 3 yrs. Two groups of patients were compared: those receiving statins in the final month before follow-up termination and those who were not.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was infection-related mortality. Of the 11,362 patients included in the final analysis, 5,698 (50.1%) belonged to the statin group. Median follow-up was 19.8 months (interquartile range, 14.3-33.3). The risk of infection-related mortality was significantly lower in the statin compared with the no-statin group (0.9% vs. 4.1%), reflecting a relative risk of 0.22 (95% confidence interval, 0.17-0.28). Stepwise Cox proportional hazard survival analysis including a propensity score for receiving statins revealed that the protective effect of statins adjusted for all known potential confounders remained highly significant (hazard ratio, 0.37; 95% confidence interval, 0.27-0.52).

CONCLUSIONS

Therapy with statins may be associated with a reduced risk of infection-related mortality. This protective effect is independent of all known comorbidities and dissipates when the medication is discontinued. If this finding is supported by prospective controlled trials, statins may play an important role in the primary prevention of infection-related mortality.

Atrial Fibrillation and Plasma Troponin I Elevation After Cardiac Surgery: Relation to Inflammation-Associated Parameters

BACKGROUND

Recent studies have demonstrated correlation between inflammation to plasma troponin (cTnI) levels elevation and atrial fibrillation (AF) in noncardiac surgery settings. The goal of this prospective study was to examine the relation between inflammation associated parameters (IAPs) to post cardiac surgery cTnI elevation and AF.

METHODS

A single post CABG cTnI measurement was assessed in 156 consecutive patients. Clinical, operative and postoperative data, IAPs (hypophosphatemia, preoperative statin treatment, immediate postoperative fever, and prolonged mechanical ventilation) and in-hospital AF episodes were prospectively recorded.

RESULTS

Mean cTnI level was 14.4 +/- 12.4 ng/mL. In the two in-hospital deaths (1.2%) cTnI concentration was less than 12 ng/mL. Cardiac troponin-I levels were significantly higher in patients not preoperatively treated with statins (21.6 +/- 4.1 vs. 13.3 +/- 0.9, p = 0.05), in patients who needed intraoperative cardioversion (16.7 +/- 2.2 vs. 12.2 +/- 0.9, p = 0.07), in patients with postoperative hypophosphatemia (16.9 +/- 10.0 vs. 11.1 +/- 13.7, p = 0.04), postoperative fever (18.6 +/- 3.0 vs. 13.7 +/- 1.0, p = 0.07) and postoperative respiratory complications (23.9 +/- 4.3 vs. 13.5 +/- 1.0, p = 0.04). Step-wise logistic regression analysis revealed the following parameters as independently associated with elevated cTnI levels: preoperative statin treatment (CI 95%-15.9; -1.7, p = 0.02), intraoperative ventricular arrhythmia (CI 95%-0.7; 13.8, p = 0.08), hypophosphatemia (CI 95% 0.9; 8.6, p = 0.02), postoperative fever (CI 95% 0.9; 11.0, p = 0.02), and postoperative respiratory complications (CI 95% 0.1; 0.5, p = 0.01). Of the 156 patients, 50 (32.1%) had postoperative AF. The first episode of AF occurred between postoperative day 1 and 6 (mean-day 2). Mean duration of AF was 21.8 +/- 8.1 hours. Postoperative AF was significantly associated with age above 75 (50% vs. 29.4%, p = 0.01), hypertension (37% vs. 18%, p = 0.02), preoperative calcium channel blockers treatment (44% vs. 26%, p = 0.02), furosemide treatment (58% vs. 30%, p = 0.05), and preoperative left atrial diameter above 40 mm (56% vs. 29%, p = 0.01). Postoperatively, AF was significantly associated with postoperative renal failure (70% vs. 29%, p = 0.01), respiratory complications (61% vs. 29%, p = 0.02), and prolonged hospital stay (OR 1.1; CI 1.0-1.3; p < 0.05). No association was found between troponin levels and postoperative AF. Multivariable analysis found only left atrial enlargement and prolonged hospital stay independently associated with AF.

CONCLUSIONS

A significant correlation between clinical IAPs and cTnI plasma level elevation was found after cardiac surgery. There was no correlation between these parameters and postoperative AF, and there was no correlation between postoperative plasma cTnI levels and the occurrence of AF. Preoperative treatment with statins may be beneficial in reducing postoperative inflammatory response but further study has to be carried out.

Statins, bugs and prophylaxis: intriguing possibilities

Statin therapy may represent a potential prophylactic intervention in certain high-risk scenarios, for example in pandemic influenza and in those undergoing aggressive medical treatments. Emerging data indicate a potential prophylactic role in these high-risk groups.

Treatment of plague: promising alternatives to antibiotics

Plague still poses a significant threat to human health, and interest has been renewed recently in the possible use of Yersinia pestis as a biological weapon by terrorists. The septicaemic and pneumonic forms are always lethal if untreated. Attempts to treat this deadly disease date back to the era of global pandemics, when various methods were explored. The successful isolation of the plague pathogen led to the beginning of more scientific approaches to the treatment and cure of plague. This subsequently led to specific antibiotic prophylaxis and therapy for Y. pestis. The use of antibiotics such as tetracycline and streptomycin for the treatment of plague has been embraced by the World Health Organization Expert Committee on Plague as the 'gold standard' treatment. However, concerns regarding the development of antibiotic-resistant Y. pestis strains have led to the exploration of alternatives to antibiotics. Several investigators have looked into the use of alternatives, such as immunotherapy, non-pathogen-specific immunomodulatory therapy, phage therapy, bacteriocin therapy, and treatment with inhibitors of virulence factors. The alternative therapies reported in this review should be further investigated by comprehensive studies of their clinical application for the treatment of plague.

Do statins have a role in preventing or treating sepsis?

Statins have a variety of properties that are independent of their lipid lowering ability. These anti-inflammatory, antioxidant, immunomodulatory, and antiapoptotic features have been collectively referred to as pleiotropic effects. Severe sepsis is an intense infection-induced inflammatory syndrome that ultimately results in organ dysfunction. Because so many cascades are triggered during sepsis, merely blocking a single component may be insufficient to arrest the inflammatory process. A growing body of evidence suggests that statins may indeed have a protective effect against severe sepsis and reduce the rate of infection-related mortality. This novel primary prevention concept may have far-reaching implications for the future management of serious infections. Moreover, it was recently shown that statins potentially improve outcome after the onset of sepsis. The stage is now set for randomized clinical trials that will determine the precise role, if any, that statins may have in preventing and treating sepsis.

Statin-associated pleiotropy: possible beneficial effects beyond cholesterol reduction

Because elevated serum cholesterol levels are strongly associated with coronary heart disease, cholesterol reduction by 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (or statins) has been assumed to be the predominant, if not the only, mechanism underlying the beneficial effects of these drugs in cardiovascular diseases. Subgroup analyses of large clinical trials, however, have suggested that the beneficial effects of statins may extend to mechanisms beyond cholesterol reduction. Indeed, recent experimental and clinical evidence indicates that some of the cholesterol-independent or "pleiotropic" effects of statins may be mediated through improving or restoring endothelial function, enhancing the stability of atherosclerotic plaques, and decreasing oxidative stress and vascular inflammation.

Statin treatment and reduced risk of pneumonia in patients with diabetes

BACKGROUND

Recent prognostic studies have shown that previous treatment with statins is associated with a better outcome in patients admitted to hospital with pneumonia. Because of an increased risk of pneumonia in patients with diabetes, we assessed the effects of statin use on the occurrence of pneumonia in adult diabetic patients.

METHODS

All patients with a diagnosis of diabetes (types 1 and 2) enlisted in the UK General Practice Research Database between 1 June 1987 and 21 January 2001 were included. A case-control study was performed with cases defined as patients with a first recorded diagnosis of pneumonia. For each case up to four controls were matched by age, sex, practice, and index date. Patients were classified as current users when the index date was between the start and end date of statin treatment. Conditional multiple logistic regression analysis was used to estimate the strength of the association between statin treatment and the occurrence of pneumonia.

RESULTS

Statins were used in 1.1% of 4719 cases and in 2.1% of 15 322 matched controls (crude odds ratio (OR) 0.51, 95% CI 0.37 to 0.68). After adjusting for potential confounders, treatment with statins was associated with a significant reduction in the risk of pneumonia (adjusted OR 0.49, 95% CI 0.35 to 0.69). The association was consistent among relevant subgroups (cardiovascular diseases, pulmonary diseases) and independent of the use of other prescription drugs.

CONCLUSIONS

The use of statins is associated with a considerable reduction in the risk of pneumonia in diabetic patients. In addition to lowering the risk of cardiovascular disease, statins may be useful in preventing respiratory infections.

Statin use and mortality within 180 days after bacteremia: a population-based cohort study

OBJECTIVE

To examine the association between preadmission statin use and mortality among patients with bacteremia in a population-based setting.

DESIGN

Observational study based on prospective registration of bacteremia episodes and mortality over a 6-yr period.

SETTING

North Jutland County, Denmark (population, 500,000).

PATIENTS

A total of 5,353 adult patients hospitalized with bacteremia from 1997 to 2002. Individuals treated with statins (n = 176) were identified by record-linkage with the County Prescription Database.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We compared mortality rates 0-30 and 31-180 days after bacteremia in patients with and without preadmission statin use, adjusted for gender, age group, level of comorbidity, alcohol-related conditions, use of immunosuppressive drugs and systemic antibiotics, and focus on infection. The 30-day mortality in statin users vs. nonusers was similar (20.0% vs. 21.6%, adjusted mortality rate ratio 0.93, 95% confidence interval 0.66-1.30). Among survivors after 30 days, however, statin therapy was associated with a substantially decreased mortality up until 180 days after the bacteremia (8.4% vs. 17.5%, adjusted mortality rate ratio 0.44, 95% confidence interval 0.24-0.80). This tendency toward similar short-term and decreased longer term mortality associated with statin use was observed consistently in both community-acquired and nosocomial bacteremia episodes and when analyses were restricted to patients with previous cardiovascular discharge diagnoses or diabetes.

CONCLUSIONS

This study provides evidence against the hypothesis that statin use has an effect on short-term mortality after bacteremia. Statin use was, however, associated with a substantially decreased mortality between 31 and 180 days after bacteremia.

Socioeconomic gradient in use of statins among Danish patients: population-based cross-sectional study

AIMS

Socioeconomic inequalities in statin use are a public health concern but they may also confound observational studies of statins' effectiveness. We conducted a population-based cross-sectional study in Denmark to examine the association between socioeconomic status (SES) and statin use.

METHODS

We obtained data on socioeconomic status of all persons in North Jutland County, Denmark, between 1995 and 1999 from the Prevention Registry at Statistics Denmark. Data on filled statin prescriptions were identified through the County Prescription Database. We compared the 1-year prevalence proportions of statin use for different socioeconomic groups, adjusted for age and urbanization. Separate analyses were done for patients with a history of cardiovascular disease as recorded in the County Hospital Discharge Registry.

RESULTS

Among men with cardiovascular disease, statin use in 1995 was higher in those with the highest socioeconomic status (adjusted relative prevalence proportion (RPP) among top managers 1.86, 95% CI: 1.17-2.96), and lower among retired men (RPP (95% CI) 0.63 [0.43-0.93] in old-age pensioners, and 0.66 [0.45-0.98] in the early retired), when compared with basic-level workers. The socioeconomic differences in statin use among men decreased in magnitude over time but remained throughout the study period. We found no clear social gradient in statin use among women.

CONCLUSIONS

Even in a health care system that claims to ensure a high degree of equity in medical care, we found clear indications of a socioeconomic gradient in statin use among men in the years after the launching of these drugs.

Statins: panacea for sepsis?

Sepsis occurs when the immune system responds to a localised infection at a systemic level, thereby causing tissue damage and organ dysfunction. Statins have proven health benefits in many diseases involving vascular inflammation and injury. Recent animal data suggest that the administration of a statin before a sepsis-inducing insult reduces morbidity and improves survival. The immunomodulatory and anti-inflammatory effects of statins, collectively referred to as pleiotropic effects, lend biological plausibility to such findings. Limited human data hint at reduced mortality rates in bacteraemic patients, and a reduced risk of sepsis in patients with bacterial infections concurrently taking statins. These lines of evidence point to a potential new treatment and prevention modality for sepsis. The stage is set for randomised controlled clinical trials that will determine whether statins represent a safe and beneficial treatment in critically ill, septic patients and whether statins are effective at preventing sepsis in high-risk clinical settings.

Acute antiinflammatory properties of statins involve peroxisome proliferator-activated receptor-alpha via inhibition of the protein kinase C signaling pathway

Statins are inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase used in the prevention of cardiovascular disease (CVD). In addition to their cholesterol-lowering activities, statins exert pleiotropic antiinflammatory effects, which might contribute to their beneficial effects not only on CVD but also on lipid-unrelated immune and inflammatory diseases, such as rheumatoid arthritis, asthma, stroke, and transplant rejection. However, the molecular mechanisms involved in these antiinflammatory properties of statins are unresolved. Here we show that the peroxisome proliferator-activated receptor (PPAR) alpha mediates antiinflammatory effects of simvastatin in vivo in models of acute inflammation. The inhibitory effects of statins on lipopolysaccharide-induced inflammatory response genes were abolished in PPARalpha-deficient macrophages and neutrophils. Moreover, simvastatin inhibited PPARalpha phosphorylation by lipopolysaccharide-activated protein kinase C (PKC) alpha. A constitutive active form of PKCalpha inhibited nuclear factor kappaB transrepression by PPARalpha whereas simvastatin enhanced transrepression activity of wild-type PPARalpha, but not of PPARalpha mutated in its PKC phosphorylation sites. These data indicate that the acute antiinflammatory effect of simvastatin occurs via PPARalpha by a mechanism involving inhibition of PKCalpha inactivation of PPARalpha transrepression activity.

Effects of simvastatin in abdominal sepsis in rats

PURPOSE: Statins are widely recognized as hypolipemic drugs, but some studies have observed anti-inflammatory and immunomodulatory effects, known as pleiotropic. The aims of this work was to study possible anti-inflammatory effects of simvastatin in abdominal sepsis. Serum pro-inflammatory cytokines and leukocytes count were determined in an experimental model of abdominal sepsis, using cecal ligation and puncture (CLP) in rats. METHODS: Twenty eigth Wistar rats weighing 285±12g were randomly divided in: CLP/Sinvastatin rats (n=7), treated with 10 mg/Kg of oral simvastatin 18 and 2 hs berofe CLP; CLP/Saline group rats (n=7), treated with oral saline; group Sham/Simvastatin (n=7), treated with simvastatin, and group Sham/Saline (n=7), treated with saline. Serum TNF-alpha, IL-1beta and IL-6 by ELISA and total leukocytes, neutrophils, lymphocytes, and eosinophils were determined 24 hs after CLP. ANOVA and Tukey test were used considering significant p<0.05. RESULTS: It was demonstrated that serum TNF-alpha, IL-1beta and IL-6 were respectively 364,8±42pg/mL; 46,3±18pg/mL and 28,4±13pg/mL in CLP/Sinvastatin rats, significantly lower (p<0.05) than in group CLP/Saline (778,5±86pg/ml; 176,9±46pg/ml; 133,6±21 pg/ml, respectively). The same results were observed in total leukocytes and neutrophils counts. CONCLUSION: These results clearly demonstrate that simvastatin is an effective agent that reduces cytokines levels and leukocyte count in sepsis, independently of its well-known lipid-lowering effects. Thus, HMG-CoA reductase inhibitors like simvastatin have important anti-inflammatory effects in abdominal sepsis in rats.

Statin therapy is associated with fewer deaths in patients with bacteraemia

OBJECTIVE

Beneficial effects with statin use are increasingly reported in a variety of patient groups. There is in vitro and clinical evidence for its antiinflammatory and immunomodulatory therapeutic roles. We aimed to assess the association between statin administration and mortality in bacteraemic patients.

DESIGN

A retrospective cohort analysis.

SETTING

A 300-bed acute general hospital.

PATIENTS AND PARTICIPANTS

All patients (n=438) requiring hospital care for an episode of bacteraemia during the years 2000-2003 were included. Statin use, patient outcome, and clinical and laboratory variables were collected.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

There was a significant reduction in all-cause hospital mortality (10.6% vs. 23.1%, p=0.022) and death attributable to bacteraemia (6.1% vs. 18.3%, p=0.014) in patients who were receiving statin therapy at the time of bacteraemia (n=66). The reduction in all-cause hospital mortality (1.8% vs. 23.1%, p=0.0002) and death attributable to bacteraemia (1.8% vs. 18.3%, p=0.0018) was more pronounced in the patients who continued to receive statin therapy after the diagnosis of bacteraemia (n=56). The apparent mortality benefit persisted after controlling for differences between the groups. Statin use prior to admission was associated with a reduced adjusted hospital mortality rate (odds ratio 0.39; CI 95% 0.17, 0.91; p=0.029), and continuing statin use after bacteraemia increased this effect (odds ratio 0.06; CI 95% 0.01, 0.44; p=0.0056).

CONCLUSION

This retrospective study demonstrates a significant survival benefit associated with continuing statin therapy in bacteraemic patients. The potential for statins as an adjuvant therapy in sepsis warrants further investigation.

Statin therapy prior to ICU admission: protection against infection or a severity marker?

OBJECTIVE

Examine the impact of previous statin therapy on hospital mortality and whether it is due to a protective effect against ICU-acquired infections.

DESIGN AND SETTING

Cohort comparison study by retrospective chart-based analysis in a 26-bed, university-affiliated, medical-surgical ICU.

PATIENTS

We analyzed data from 438 patients at high risk of ICU-acquired infections, i.e., those receiving mechanical ventilation for more than 96 h, 38 (8.7%) of whom had been treated with statins prior to and during ICU admission.

MEASUREMENTS AND RESULTS

We recorded clinical characteristics, number and type of ICU-acquired infections, and ICU and hospital mortality. Statin-treated patients were older (71.7+/-8.3 vs. 61.5+/-18.3 years), but differences in predicted mortality risk by APACHE II (39.5+/-24.7 vs. 35.8+/-24.3%) did not reach statistical significance. The ICU-acquired infection rate in statin-treated patients was nonsignificantly lower (29% vs. 38%) and delayed (median 12 vs.10 days), without differences regarding the source of infections. Nevertheless, hospital mortality was significantly higher in statin-treated patients (61% vs. 42%), even after adjustment for APACHE II predicted risk (observed/expected ratio 1.53 vs. 1.17).

CONCLUSIONS

Statin therapy is associated with worse outcome, probably because underlying clinical conditions are insufficiently considered in mortality predictors. Its presumed protective effect against ICU infections remains unconfirmed.

Statins Reduce Interleukin-6–Induced C-Reactive Protein in Human Hepatocytes

Objectives— Besides its predictive role in determining cardiovascular risk, C-reactive protein (CRP) may exert direct proatherogenic effects through proinflammatory properties. CRP is mainly produced by hepatocytes in response to interleukin-6 (IL-6) and is then released into the systemic circulation. 3-hydroxy-3-methylglutaryl (HMG)-coenzyme A (CoA) reductase inhibitors, or statins, significantly reduce cardiovascular events and mortality in patients with or without coronary artery disease and reduce plasma CRP levels in humans. However, the mechanism by which statins reduce plasma CRP levels remains unknown.

Methods and Results— In this study, we report that statins limit both protein and RNA levels of IL-6-induced CRP in human hepatocytes. These effects are reversed by l -mevalonate and mimicked by an inhibitor of the geranylgeranyltransferase. IL-6–induced CRP production requires the binding of IL-6 to its cognate receptors, which results in activation and phosphorylation of the transcription factor STAT3. We provide evidence that statins reduce this IL-6–induced phosphorylation of STAT3 in hepatocytes.

Conclusion— These results demonstrate that statins reduce IL-6–induced CRP production directly in hepatocytes via inhibition of protein geranylgeranylation. We further show that statins act via inhibition of STAT3 phosphorylation. These findings furnish new evidence for direct antiinflammatory properties of statins and provide new mechanistic insight into their clinical benefits.

The "Statinth" wonder of the world: a panacea for all illnesses or a bubble about to burst

After the introduction of statins in the market as effective lipid lowering agents, they were shown to have effects other than lipid lowering. These actions were collectively referred to as 'pleiotropic actions of statins.' Pleiotropism of statins formed the basis for evaluating statins for several indications other than lipid lowering. Evidence both in favour and against is available for several of these indications. The current review attempts to critically summarise the available data for each of these indications.

A role for hydroxy-methylglutaryl coenzyme a reductase in pulmonary inflammation and host defense

RATIONALE

A growing literature indicates that hydroxy-methylglutaryl coenzyme A reductase inhibitors (statins) modulate proinflammatory cellular signaling and functions. No studies to date, however, have addressed whether statins modulate pulmonary inflammation triggered by aerogenic stimuli or whether they affect host defense.

OBJECTIVES

To test whether lovastatin modulates LPS-induced pulmonary inflammation and antibacterial host defense.

METHODS

To address these questions, and to confirm any effect of statins as dependent on inhibition of hydroxy-methylglutaryl coenzyme A reductase, we treated C57Bl/6 mice with three oral doses of 10 mg/kg lovastatin (or vehicle) and three intraperitoneal doses of 10 mg/kg mevalonic acid (or saline), and then exposed them to the following: (1) aerosolized LPS, (2) intratracheal keratinocyte-derived chemokine (KC), or (3) intratracheal Klebsiella pneumoniae.

MEASUREMENTS AND MAIN RESULTS

LPS- and KC-induced airspace neutrophils were reduced by lovastatin, an effect that was blocked by mevalonic acid cotreatment. Lovastatin was also associated with reduced parenchymal myeloperoxidase and microvascular permeability, and altered airspace and serum cytokines after LPS. Native pulmonary clearance of K. pneumoniae was inhibited by lovastatin and extrapulmonary dissemination was enhanced, both reversibly with mevalonic acid. Ex vivo studies of neutrophils isolated from lovastatin-treated mice confirmed inhibitory effects on Rac activation, actin polymerization, chemotaxis, and bacterial killing.

CONCLUSION

Lovastatin attenuates pulmonary inflammation induced by aerosolized LPS and impairs host defense.

Potential Role of Endotoxin as a Proinflammatory Mediator of Atherosclerosis

Atherosclerosis is increasingly recognized as a chronic inflammatory disease. Although a variety of inflammatory markers (ie, C-reactive protein) have been associated with atherosclerosis and its consequences, it is important to identify principal mediators of the inflammatory responses. One potentially important source of vascular inflammation in atherosclerosis is bacterial endotoxin. Mutations in Toll-like receptor 4 (TLR-4), an integral component of the endotoxin signaling complex, are fairly common in the Caucasian population and have recently been associated with reduced incidence of atherosclerosis and other cardiovascular diseases in some studies. Moreover, epidemiological studies suggest that endotoxemia at levels as low as 50 pg/mL constitutes a strong risk factor for the development of atherosclerosis. Endotoxin concentrations in this range may be produced by a variety of common subclinical Gram-negative infections. In this article, we outline the main elements of the endotoxin signaling receptor complex that initiates proinflammatory signaling (lipopolysaccharide binding protein [LBP], CD14, TLR-4, and MD-2) and discuss how changes in expression of these molecules may affect proatherogenic responses in the vessel wall. We also describe some of the proinflammatory effects of endotoxin that may be relevant to atherosclerosis, and discuss how serum lipoproteins, especially high-density lipoprotein, may modulate endotoxin-induced inflammatory responses. Further, we discuss recent findings suggesting that the lipid-lowering statins may have an additional protective role in blocking at least some of these proinflammatory signaling pathways. Finally, we discuss species diversity with regard to endotoxin signaling that should be considered when extrapolating experimental data from animal models to humans.

Prior statin therapy is associated with a decreased rate of severe sepsis

BACKGROUND

Statins have anti-inflammatory properties that are independent of their lipid-lowering abilities. We hypothesized that statin therapy before the onset of an acute bacterial infection may have a protective effect against severe sepsis. The aim of this study was to determine whether patients treated with statins develop severe sepsis less frequently.

METHODS AND RESULTS

In this prospective observational cohort study, consecutive patients admitted with presumed or documented acute bacterial infection were enrolled. The primary outcomes were the rate of severe sepsis and intensive care unit (ICU) admission. Of the 361 patients enrolled, 82 (22.7%) were treated with statins before their admission. Both groups had a similar severity of illness on admission. Severe sepsis developed in 19% of patients in the no-statin group and in only 2.4% of the statin group (P<0.001). Statin treatment was associated with a relative risk of developing severe sepsis of 0.13 (95% CI, 0.03 to 0.52) and an absolute risk reduction of 16.6%. The overall ICU admission rate was 10.2% (37/361): 12.2% of the no-statin group required ICU admission, whereas in the statin group only 3.7% were admitted to the ICU (P=0.025), reflecting a relative risk of ICU admission of 0.30 (95% CI, 0.1 to 0.95).

CONCLUSIONS

Prior therapy with statins may be associated with a reduced rate of severe sepsis and ICU admission. If supported by prospective controlled trials, statins may have a role in the primary prevention of sepsis.

Simvastatin Decreases Nitric Oxide Overproduction and Reverts the Impaired Vascular Responsiveness Induced by Endotoxic Shock in Rats

Lipopolysaccharides (LPS) can be used to induce experimental endotoxic shock, which is characterized by a significant decrease in mean arterial pressure (MAP) and a decreased vasoconstrictor response that have been attributed to excessive nitric oxide production. Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase), in addition to lowering serum cholesterol levels, exert many pleiotropic effects, including anti-inflammatory action. In the present study, we investigated the effect of simvastatin, an HMG-CoA reductase inhibitor, on the production of nitric oxide and the cardiovascular response to LPS. Male Wistar rats were pretreated with different doses of simvastatin (10, 20, 40, and 80 mg/kg, i.p.) or saline 20 min before i.v. injection of LPS (1.5 mg/kg) or saline (control). MAP was continuously recorded and nitrate plasma concentration was determined during the 6-h experimental session at 1-h intervals. The pressor response to phenylephrine (1 microg/kg) was evaluated before and 6 h after LPS administration. In the LPS-treated group, there was a time-dependent increase in nitrate plasma concentration (P<0.001), and this response was decreased in simvastatin pretreated rats (P<0.001). We also observed that LPS decreased the pressor response to phenylephrine (P<0.001), an effect that was reverted by simvastatin pretreatment (P<0.05). However, simvastatin did not modify the decrease of MAP induced by LPS. We concluded that simvastatin decreases nitrate plasma concentration in response to LPS and recovers vascular responsiveness during an experimental endotoxic shock. These data suggest the potential use of HMG-CoA reductase inhibitors as a coadjuvant in the treatment of septic shock.