Beneficial effects of statins on the microcirculation during sepsis: the role of nitric oxide

Gemfibrozil Improves Microcirculatory Oxygenation of Colon and Liver without Affecting Mitochondrial Function in a Model of Abdominal Sepsis in Rats

Recent studies observed, despite an anti-hyperlipidaemic effect, a positive impact of fibrates on septic conditions. This study evaluates the effects of gemfibrozil on microcirculatory variables, mitochondrial function, and lipid peroxidation levels with regard to its potential role as an indicator for oxidative stress in the colon and liver under control and septic conditions and dependencies on PPARα-mediated mechanisms of action. With the approval of the local ethics committee, 120 Wistar rats were randomly divided into 12 groups. Sham and septic animals were treated with a vehicle, gemfibrozil (30 and 100 mg/kg BW), GW 6471 (1 mg/kg BW, PPARα inhibitor), or a combination of both drugs. Sepsis was induced via the colon ascendens stent peritonitis (CASP) model. Then, 24 h post sham or CASP surgery, a re-laparotomy was performed. Measures of vital parameters (heart rate (HR), mean arterial pressure (MAP), and microcirculation (µHbO2)) were recorded for 90 min. Mitochondrial respirometry and assessment of lipid peroxidation via a malondialdehyde (MDA) assay were performed on colon and liver tissues. In the untreated sham animals, microcirculation remained stable, while pre-treatment with gemfibrozil showed significant decreases in the microcirculatory oxygenation of the colon. In the CASP animals, µHbO2 levels in the colon and the liver were significantly decreased 90 min after laparotomy. Pre-treatment with gemfibrozil prevented the microcirculatory aberrations in both organs. Gemfibrozil did not affect mitochondrial function and lipid peroxidation levels in the sham or CASP animals. Gemfibrozil treatment influences microcirculation depending on the underlying condition. Gemfibrozil prevents sepsis-induced microcirculatory aberrances in the colon and liver PPARα-independently. In non-septic animals, gemfibrozil impairs the microcirculatory variables in the colon without affecting those in the liver.

The Relationship between Delirium and Statin Use According to Disease Severity in Patients in the Intensive Care Unit

Objective

The aim of this study was to investigate the association between the use of statins and the occurrence of delirium in a large cohort of patients in the intensive care unit (ICU), considering disease severity and statin properties.

Methods

We obtained clinical and demographical information from 3,604 patients admitted to the ICU from January 2013 to April 2020. This included information on daily statin use and delirium state, as assessed by the Confusion Assessment Method for ICU. We used inverse probability of treatment weighting and categorized the patients into four groups based on the Acute Physiology and Chronic Health Evaluation II score (group 1: 0-10 - mild; group 2: 11-20 - mild to moderate; group 3: 21-30 - moderate to severe; group 4: > 30 - severe). We analyzed the association between the use of statin and the occurrence of delirium in each group, while taking into account the properties of statins.

Results

Comparisons between statin and non-statin patient groups revealed that only in group 2, patients who were administered statin showed significantly higher occurrence of delirium (p = 0.004, odds ratio [OR] = 1.58) compared to the patients who did not receive statin. Regardless of whether statins were lipophilic (p = 0.036, OR = 1.47) or hydrophilic (p = 0.032, OR = 1.84), the occurrence of delirium was higher only in patients from group 2.

Conclusion

The use of statins may be associated with the increases in the risk of delirium occurrence in patients with mild to moderate disease severity, irrespective of statin properties.

Neurogenic Hypertension, the Blood-Brain Barrier, and the Potential Role of Targeted Nanotherapeutics

Hypertension is a major health concern globally. Elevated blood pressure, initiated and maintained by the brain, is defined as neurogenic hypertension (NH), which accounts for nearly half of all hypertension cases. A significant increase in angiotensin II-mediated sympathetic nervous system activity within the brain is known to be the key driving force behind NH. Blood pressure control in NH has been demonstrated through intracerebrovascular injection of agents that reduce the sympathetic influence on cardiac functions. However, traditional antihypertensive agents lack effective brain permeation, making NH management extremely challenging. Therefore, developing strategies that allow brain-targeted delivery of antihypertensives at the therapeutic level is crucial. Targeting nanotherapeutics have become popular in delivering therapeutics to hard-to-reach regions of the body, including the brain. Despite the frequent use of nanotherapeutics in other pathological conditions such as cancer, their use in hypertension has received very little attention. This review discusses the underlying pathophysiology and current management strategies for NH, as well as the potential role of targeted therapeutics in improving current treatment strategies.

Evaluation of statins as a new therapy to alleviate chronotropic dysfunction in cirrhotic rats

AIMS

Liver cirrhosis defines by regenerative nodules and fibrotic septa, causing a complication called cirrhotic cardiomyopathy (CCM) with chronotropic hypo-responsiveness. In addition to lowering cholesterol levels, statins yield antioxidant and anti-inflammatory effects. In liver diseases animal models, statins have been shown to decrease hepatic inflammation, fibrogenesis, and portal pressure (PP). Therefore, we evaluated the atorvastatin effect on the heart in cirrhotic rats.

MATERIALS AND METHODS

Bile duct ligation (BDL) or sham operation performed on male Wistar rats and grouped as cirrhotic; BDL/Saline, BDL/Ator-7d(days) (Atorvastatin 15 mg/kg/day), and BDL/Ator-14d groups, or control; Sham/Saline, Sham/Ator-7d, and Sham/Ator-14d groups. Corrected QT interval (QTc interval), chronotropic responses, serum brain natriuretic peptides (BNP), heart tumor necrosis factor-α (TNF-α), nuclear factor erythroid 2-related factor 2 (Nrf2), and malondialdehyde (MDA) levels were studied along with atrial Ras homolog family member A (RhoA) and endothelial nitric oxide synthase (eNOS) gene expression.

KEY FINDINGS

The chronotropic responses decreased in BDL/Saline and increased in BDL/Ator-7d group. The QTc interval, BNP, TNF-α, and MDA levels increased in BDL/Saline and decreased in BDL/Ator-14d group. The Nrf2 level did not change in BDL/Saline and increased in BDL/Ator-14d group. The liver inflammation and fibrosis increased in BDL/Saline and did not affect BDL/Ator-7d and BDL/Ator-14d groups. The RhoA expression was down-regulated in BDL/Saline, BDL/Ator-7d, and BDL/Ator-14d groups. The eNOS expression did not change in BDL/Saline and down-regulated in BDL/Ator-14d group.

SIGNIFICANCE

Atorvastatin alleviates the chronotropic hypo-responsiveness and down-regulates the atrial RhoA and eNOS gene expression along with anti-inflammatory, antioxidant, and anti-stress effects in CCM.

Involvement of Fatty Acids and Their Metabolites in the Development of Inflammation in Atherosclerosis

Despite all the advances of modern medicine, atherosclerosis continues to be one of the most important medical and social problems. Atherosclerosis is the cause of several cardiovascular diseases, which are associated with high rates of disability and mortality. The development of atherosclerosis is associated with the accumulation of lipids in the arterial intima and the disruption of mechanisms that maintain the balance between the development and resolution of inflammation. Fatty acids are involved in many mechanisms of inflammation development and maintenance. Endothelial cells demonstrate multiple cross-linkages between lipid metabolism and innate immunity. In addition, these processes are linked to hemodynamics and the function of other cells in the vascular wall, highlighting the central role of the endothelium in vascular biology.

Beneficial effect of simvastatin on human umbilical vein endothelial cells gap junctions induced by TNF-α

Although simvastatin has been shown to inhibit vascular permeability, which might be amplified via gap junction intercellular communication (GJIC), the underlying mechanism of action remains unclear. In the present study, we investigated the effects and mechanisms of simvastatin on endothelial cells GJIC. Specifically, human umbilical vein endothelial cells (HUVECs) were stimulated with TNF-α (10 ng/mL) alone or in combination with simvastatin (5 µM), and their effects on vascular endothelial cell GJIC tested via the scrape loading/dye transfer (SL/DT) assay. Next, we performed immunofluorescence, real-time PCR and western blot assays to analyze expression of Cx37, Cx40 and Cx43 in HUVECs. Results showed that GJIC activity in HUVECs was markedly elevated in HUVECs treated with TNF-α in combination with simvastatin. In addition, simvastatin treatment significantly upregulated expression of Cx37 and Cx40 but downregulated Cx43 mRNAs and proteins. Taken together, these marked changes indicated that simvastatin exerts its regulatory effects on gap junction function by upregulating Cx37 and Cx40 and downregulating Cx43 expression.

Effect of Pravastatin Pretreatment and Hypercapnia on Intestinal Microvascular Oxygenation and Blood Flow During Sepsis

INTRODUCTION

In septic patients, adequate microvascular oxygenation (μHBO2) of the intestine is vital for their outcome. Recent studies suggest that statins can ameliorate septic microcirculation in a variety of tissues. However, the effect on intestinal microvascular oxygenation and blood flow is largely unknown. Furthermore, there are indications that statin therapy might not be beneficial in the presence of hypercapnia, as observed in septic acute respiratory distress syndrome (ARDS) patients. Therefore, the present study explores the effect of pravastatin with and without additional moderate acute hypercapnia on intestinal microvascular oxygenation and blood flow in experimental sepsis.

METHODS

Forty male Wistar rats were randomized into four groups. Half of the animals received 0.2 mg • kg pravastatin s.c., the other half received the same volume as vehicle (NaCl 0.9%). After 18 h, colon ascendens stent peritonitis surgery was conducted in all animals to induce sepsis. Twenty-four hours after surgery, baseline was established and the animals were subjected to either 120 min of normocapnic (pCO2 40 ± 6 mm Hg) or moderate hypercapnic (pCO2 72 ± 10 mm Hg) ventilation. Microcirculatory oxygenation (μHBO2) and perfusion (μflow) of the colon were continuously recorded using tissue reflectance spectrophotometry and laser Doppler, respectively.

RESULTS

In normocapnic septic animals μHBO2 decreased over time (-8.4 ± 8.7%; P < 0.05 vs. baseline), whereas after pravastatin pretreatment μHBO2 remained constant (-1.9 ± 5.7% vs. baseline). However, in hypercapnic septic animals pretreated with pravastatin μHBO2 declined significantly over time (-8.9 ± 11.8%; P < 0.05 vs. baseline) and was significantly lower compared with normocapnic pravastatin-pretreated animals. μflow did not change over time in any group.

CONCLUSION

Pravastatin pretreatment ameliorates the intestinal microvascular oxygenation in sepsis and thus seems to prevent intestinal hypoxia. Furthermore, we demonstrated that additional hypercapnia abolishes this effect, indicating why septic ARDS patients might not benefit from pravastatin therapy.

Statin-Induced Nitric Oxide Signaling: Mechanisms and Therapeutic Implications

In addition to their cholesterol-lowering effects, statins are associated with pleiotropic effects including improvements in heart failure (HF), reduced blood pressure, prevention of the rupture of atherosclerotic plaques and improved angiogenesis. In addition to these cardiovascular benefits, statins have been implicated in the treatment of neurological injuries, cancer, sepsis, and cirrhosis. These cholesterol-independent beneficial effects of statins are predominantly mediated through signaling pathways leading to increased production and bioavailability of nitric oxide (NO). In this review, the mechanistic pathways and therapeutic effects of statin-mediated elevations of NO are described and discussed.

Simvastatin Modulates Interaction Between Vascular Smooth Muscle Cell/Macrophage and TNF-α-Activated Endothelial Cell

Cellular interactions between endothelial cell (EC) and vascular smooth muscle cell (VSMC)/macrophages seem to be greatly changed under inflammatory conditions. Although simvastatin could regulate inflammatory transcription factors in EC and VSMC and also could inhibit leukocyte-endothelium interaction, whether it could modulate VSMC/macrophage functions that are induced by tumor necrosis factor-α (TNF-α)-activated EC remained unclear. The purpose of this study was to investigate the effects of simvastatin on VSMC/macrophage functions, which are induced by TNF-α-activated EC in coculture system in vitro. The results showed that under noncontacting conditions, simvastatin could reduce the proliferation, apoptosis, and TNF-α, IL-6, and vascular endothelial growth factor secretion both in VSMC and macrophage, which is induced by TNF-α-activated EC. And a hypothesis that simvastatin regulates the interactions and the soluble factors between EC and VSMC/macrophages could be drawn. And that might be a potential anti-atherosclerosis mechanism of simvastatin.

Endothelial Nitric Oxide Pathways in the Pathophysiology of Dengue: A Prospective Observational Study

BACKGROUND

Dengue can cause increased vascular permeability that may lead to hypovolemic shock. Endothelial dysfunction may underlie this; however, the association of endothelial nitric oxide (NO) pathways with disease severity is unknown.

METHODS

We performed a prospective observational study in 2 Vietnamese hospitals, assessing patients presenting early (<72 hours of fever) and patients hospitalized with warning signs or severe dengue. The reactive hyperemic index (RHI), which measures endothelium-dependent vasodilation and is a surrogate marker of endothelial function and NO bioavailability, was evaluated using peripheral artery tonometry (EndoPAT), and plasma levels of l-arginine, arginase-1, and asymmetric dimethylarginine were measured at serial time-points. The main outcome of interest was plasma leakage severity.

RESULTS

Three hundred fourteen patients were enrolled; median age of the participants was 21(interquartile range, 13-30) years. No difference was found in the endothelial parameters between dengue and other febrile illness. Considering dengue patients, the RHI was significantly lower for patients with severe plasma leakage compared to those with no leakage (1.46 vs 2.00; P < .001), over acute time-points, apparent already in the early febrile phase (1.29 vs 1.75; P = .012). RHI correlated negatively with arginase-1 and positively with l-arginine (P = .001).

CONCLUSIONS

Endothelial dysfunction/NO bioavailability is associated with worse plasma leakage, occurs early in dengue illness and correlates with hypoargininemia and high arginase-1 levels.

Oxidative-Nitrosative Stress and Myocardial Dysfunctions in Sepsis: Evidence from the Literature and Postmortem Observations

BACKGROUND

Myocardial depression in sepsis is common, and it is associated with higher mortality. In recent years, the hypothesis that the myocardial dysfunction during sepsis could be mediated by ischemia related to decreased coronary blood flow waned and a complex mechanism was invoked to explain cardiac dysfunction in sepsis. Oxidative stress unbalance is thought to play a critical role in the pathogenesis of cardiac impairment in septic patients.

AIM

In this paper, we review the current literature regarding the pathophysiology of cardiac dysfunction in sepsis, focusing on the possible role of oxidative-nitrosative stress unbalance and mitochondria dysfunction. We discuss these mechanisms within the broad scenario of cardiac involvement in sepsis.

CONCLUSIONS

Findings from the current literature broaden our understanding of the role of oxidative and nitrosative stress unbalance in the pathophysiology of cardiac dysfunction in sepsis, thus contributing to the establishment of a relationship between these settings and the occurrence of oxidative stress. The complex pathogenesis of septic cardiac failure may explain why, despite the therapeutic strategies, sepsis remains a big clinical challenge for effectively managing the disease to minimize mortality, leading to consideration of the potential therapeutic effects of antioxidant agents.

The association between prior statin use and long-term outcomes after critical care admission

BACKGROUND

Statins may have immunomodulatory effects that benefit critically ill patients. Therefore, we retrospectively examined the association between survival and the prescription of statins prior to admission to an intensive care unit (ICU), or high dependency unit (HDU), as a result of major elective surgery or as an emergency with a presumed diagnosis of sepsis.

METHODS

We retrospectively studied critical care patients (ICU or HDU) from a tertiary referral UK teaching hospital. Nottingham University Hospitals have more than 2200 beds, of which 39 are critical care beds. Over a 5-year period (2000-2005), 414 patients were identified with a presumed diagnosis of sepsis, and 672 patients were identified who had planned ICU/HDU admissions following elective major surgery. Patients prescribed statins prior to hospital admission were compared with those who were not. Demographics, medical history, drug history, and Acute Physiology and Chronic Health Evaluation II scores were examined. Univariate and multivariate analyses were applied using the primary end point of survival at 5 years after admission.

RESULTS

Patients prescribed statins prior to critical care admission were, on average, older and had higher initial Acute Physiology and Chronic Health Evaluation II scores and more preexisting comorbidities. Statins were almost invariably stopped following admission to critical care. Statin use was not associated with significantly altered survival during hospital admission, or at 5 years, for either patients with sepsis (9% vs 15%, P=.121; 73% vs 84%, P=.503, respectively) or postoperative patients (55% vs 58%, P=.762; 57% vs 63%, P=.390).

CONCLUSIONS

Prior statin use was not associated with improved outcomes in patients admitted to critical care after elective surgical cases or with a presumed diagnosis of sepsis.

Atorvastatin reduces endotoxin-induced microvascular inflammation via NOSII

In a lipopolysaccharide (LPS)-induced rat model of sepsis (endotoxaemia), we previously demonstrated that pravastatin reduced microvascular inflammation via increased endothelial nitric oxide synthase III (NOSIII). This study aimed to determine whether atorvastatin, the most commonly used statin for lowering cholesterol, exerted beneficial pleiotropic effects via a similar mechanism. The mesenteric microcirculation of anaesthetised male Wistar rats (308 ± 63 g, n = 54) was prepared for fluorescent intravital microscopy. Over 4 h, animals received intravenous (i.v.) administration of either saline, LPS (150 μg kg(-1) h(-1)) or LPS + atorvastatin (200 μg kg(-1) s.c., 18 and 3 h before LPS), with/without the non-specific NOS inhibitor L-NG-Nitroarginine Methyl Ester (L-NAME) (10 μg kg(-1) h(-1)) or NOSII-specific inhibitor 1400 W (20 μg kg(-1) min(-1)). LPS decreased mean arterial blood pressure (MAP) (4 h, control 113 ± 20 mmHg; LPS 70 ± 23 mmHg), being reversed by atorvastatin (105 ± 3 mmHg) (p < 0.05). LPS also increased macromolecular leak measured after 100 mg kg(-1) of i.v FITC-BSA (arbitrary grey level adjacent to venules), which again was attenuated by atorvastatin (control 1.9 ± 4.0; LPS 12.0 ± 2.4; LPS + atorvastatin 4.5 ± 2.2) (p < 0.05). Furthermore, immunohistochemistry identified that atorvastatin decreased LPS-induced upregulation of endothelial cell NOSII expression, but NOSIII was unchanged in all groups. Atorvastatin improved MAP and reduced microvascular inflammation during endotoxaemia, associated with a reduction of pro-inflammatory NOSII. This differs from previous studies, whereby pravastatin increased expression of NOSIII. Thus preoperative statins have beneficial anti-inflammatory effects during endotoxaemia, but careful consideration must be given to the specific statin being used.

Increased plasma arginase activity in human sepsis: association with increased circulating neutrophils

BACKGROUND

The pathophysiology of sepsis is incompletely understood. Impaired bioavailability of L-arginine, the substrate for NO synthesis, is linked to sepsis severity, and plasma arginase has been linked to hypoargininemia in other disease states. Circulating neutrophils are increased in sepsis and constitutively express arginase. We investigated whether plasma arginase activity is increased in human sepsis and whether this is associated with neutrophil numbers and activation.

METHODS

We used HPLC and a radiometric assay to evaluate plasma amino acid concentrations and plasma arginase activity. The relationships between plasma arginase activity, neutrophil count, neutrophil activity and plasma L-arginine and arginine metabolites were evaluated in 44 sepsis patients and 25 controls.

RESULTS

Plasma arginase activity was increased in sepsis patients, correlated with neutrophil count (r=0.44; p=0.003), but was independent of sepsis severity (SOFA or APACHE II score). Plasma HNP1-3 correlated with neutrophil count (r=0.31; p=0.04), was elevated in shock (median 180 ng/mL vs. 83 ng/mL sepsis without shock, p=0.0006) and correlated with SOFA score. Sepsis patients with high neutrophil counts had significantly higher plasma HNP1-3 and arginase activity and lower plasma L-arginine concentrations than those with lower neutrophil counts and controls.

CONCLUSIONS

Plasma arginase activity, potentially derived in part from neutrophil activation, is elevated in sepsis, and may contribute to impaired bioavailability of L-arginine in sepsis.

Millettia pachycarpa exhibits anti-inflammatory activity through the suppression of LPS-induced NO/iNOS expression

The present study was designed to investigate the in vitro and in vivo anti-inflammatory activity of flavonoids isolated from Millettia pachycarpa Benth. The seeds of M. pachycarpa Benth were extracted with ethanol and subjected to chromatographic separation for the isolation of bioactive compounds. Their structures were elucidated by spectroscopic methods. The anti-inflammatory activity of the compounds was investigated by evaluating the inhibition ability of NO production, iNOS activity and iNOS protein expression induced by LPS-stimulated RAW264.7 macrophages in vitro and the carrageenan-induced hind paw edema model in vivo. Molecular docking simulation was also employed to obtain the binding parameters in the binding pocket of iNOS. Thirteen compounds (1-13) were isolated from Chinese herbal medicine M. pachycarpa Benth. Among them, 4-hydroxylonchocarpin (6) and deguelin (7) exhibited remarkable inhibitory rates of 66.5% and 57.7%, respectively, compared with that of 52.5% of indomethacin in LPS-induced macrophages cells. 4-hydroxylonchocarpin (6) with low toxicity (IC50 > 100 μm) exhibited better inhibitory effects to positive control of 1400W on iNOS activity at the concentration of 10 μm. Western blot assay revealed that 4-hydroxylonchocarpin (6) inhibited iNOS protein expression in RAW264.7 cells and molecular docking simulation showed that 4-hydroxylonchocarpin (6) fit well into the binding pocket of iNOS. In the carrageenan-induced paw edema model, our data revealed that the anti-inflammatory potential of 4-hydroxylonchocarpin (6) at 10 mg/kg showed comparable inhibitory ability to indomethacin at 5 h while a higher concentration of 4-hydroxylonchocarpin (6) at 50 mg/kg showed higher inhibitory activity than indomethacin, which was further confirmed by plasma levels of nitrite. The overall results suggest that 4-hydroxylonchocarpin (6) might be used as a potential therapeutic agent for inflammation-associated disorders.

Statin treatment and mortality: propensity score-matched analyses of 2007-2008 and 2009-2010 laboratory-confirmed influenza hospitalizations

Background.  Annual influenza epidemics are responsible for substantial morbidity and mortality. The use of immunomodulatory agents such as statins to target host inflammatory responses in influenza virus infection has been suggested as an adjunct treatment, especially during pandemics, when antiviral quantities are limited or vaccine production can be delayed. Methods.  We used population-based, influenza hospitalization surveillance data, propensity score-matched analysis, and Cox regression to determine whether there was an association between mortality (within 30 days of a positive influenza test) and statin treatment among hospitalized cohorts from 2 influenza seasons (October 1, 2007 to April 30, 2008 and September 1, 2009 to April 31, 2010). Results.  Hazard ratios for death within the 30-day follow-up period were 0.41 (95% confidence interval [CI], .25-.68) for a matched sample from the 2007-2008 season and 0.77 (95% CI, .43-1.36) for a matched sample from the 2009 pandemic. Conclusions.  The analysis suggests a protective effect against death from influenza among patients hospitalized in 2007-2008 but not during the pandemic. Sensitivity analysis indicates the findings for 2007-2008 may be influenced by unmeasured confounders. This analysis does not support using statins as an adjunct treatment for preventing death among persons hospitalized for influenza.

Chronic Statin Use and Long-Term Rates of Sepsis: A Population-Based Cohort Study

PURPOSE

"Statins" have immunomodulatory and anti-inflammatory effects and may attenuate the risk of infections. We sought to determine the association between chronic statin use and long-term rates of sepsis events.

MATERIALS AND METHODS

We used data from 30 183 adult (≥45 years old) community-dwelling participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. The primary exposure was statin use. The primary outcome was hospitalization or emergency department treatment for sepsis. Using Cox proportional hazards models, we determined associations between statin use and first sepsis events, adjusting for patients demographics, health behaviors, chronic medical conditions, degree of medication adherence, baseline high-sensitivity C-reactive protein (hsCRP), and propensity for statin use.

RESULTS

Approximately one-third of participants reported statin use (n = 9475, 31.4%). During the 10-year follow-up period from 2003 to 2012, there were 1500 incident sepsis events. Statin use was not associated with rates of sepsis after multivariable adjustment for demographics, health behaviors, chronic medical conditions, medication adherence, abnormal hsCRP, and propensity for statin use, hazard ratio 0.93 (95% confidence interval: 0.81-1.06). Statin use was not similarly associated with rates of sepsis when stratified by propensity for statin use or medication adherence.

CONCLUSION

In the REGARDS cohort, statin use at baseline was not associated with rates of future sepsis events.

Fluid resuscitation therapy in endotoxemic hamsters improves survival and attenuates capillary perfusion deficits and inflammatory responses by a mechanism related to nitric oxide

Background

Relative hypovolemia is frequently found in early stages of severe sepsis and septic shock and prompt and aggressive fluid therapy has become standard of care improving tissue perfusion and patient outcome. This paper investigates the role of the nitric oxide pathway on beneficial microcirculatory effects of fluid resuscitation.

Methods

After skinfold chamber implantation procedures and endotoxemia induction by intravenous Escherichia coli lipopolysaccharide administration (2 mg.kg⁻¹), male golden Syrian hamsters were fluid resuscitated and then sequentially treated with L-N^ω-Nitroarginine and L-Arginine hydrochloride (LPS/FR/LNNA group). Intravital microscopy of skinfold chamber preparations allowed quantitative analysis of microvascular variables including venular leukocyte rolling and adhesion. Macro-hemodynamic, biochemical and hematological parameters as well as survival rate were also evaluated. Endotoxemic hamsters treated with fluid therapy alone (LPS/FR group) and non-treated animals (LPS group) served as controls.

Results

Fluid resuscitation was effective in reducing lipopolysaccharide-induced microcirculatory changes. After 3 hours of lipopolysaccharide administration, non-fluid resuscitated animals (LPS group) had the lowest functional capillary density (1% from baseline for LPS group vs. 19% for LPS/FR one; p <0.05). At the same time point, arteriolar mean internal diameter was significantly wider in LPS/FR group than in LPS one (100% vs. 50% from baseline). Fluid resuscitation also reduced leukocyte-endothelium interactions and sequestration (p <0.05 for LPS vs. LPS/FR group) and increased survival (median survival time: 2 and 5.5 days for LPS and LPS/FR groups, respectively; p <0.05). Nitric oxide synthase inhibition prevented these protective effects, while L-Arginine administration markedly restored many of them.

Conclusion

Our results suggest that the underlying mechanism of fluid therapy is the restoration of nitric oxide bioavailability, because inhibition of NOS prevented many of its beneficial effects. Nevertheless, further investigations are required in experimental models closer to conditions of human sepsis to confirm these results.

Cardiovascular manifestations of the emerging dengue pandemic

Dengue is one of the most important emerging viral diseases globally. The majority of symptomatic infections result in a relatively benign disease course. However, a small proportion of patients develop severe clinical manifestations, including bleeding, organ impairment, and endothelial dysfunction with increased capillary permeability causing hypovolaemic shock that can lead to cardiovascular collapse. Evidence is increasing that dengue can also cause myocardial impairment, arrhythmias and, occasionally, fulminant myocarditis. No antiviral agents or vaccines are licensed for dengue, and treatment remains supportive with judicious fluid replacement for patients with severe disease. Defining the role of cardiac dysfunction in the haemodynamic compromise of severe dengue has potentially important management implications. In this Review, we will outline the current understanding of the cardiovascular manifestations of dengue, including myocardial and vascular involvement, and conclude with a discussion of the available therapeutic options and potential future research directions.

The effect of statin therapy on the incidence of infections: a retrospective cohort analysis

BACKGROUND

Statins have been postulated to prevent infection through immunomodulatory effects.

OBJECTIVES

To compare the incidence of infections in statin users to that in nonusers within the same health care system.

METHODS

This was a retrospective cohort study of patients enrolled as Tricare Prime or Plus in the San Antonio military multimarket. Statin users were patients who received a statin for at least 3 months between October 1, 2004 and September 30, 2005. Nonusers were patients who did not receive a statin within the study period (October 1, 2003-September 30, 2009). Inpatient and outpatient International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes were used to determine the incidence of infections during the follow-up period (October 1, 2005-September 30, 2009) via multivariable regression analysis and time to infection via Cox regression analysis.

RESULTS

Of 45,247 patients who met the study criteria, 12,981 (29%) were statin users and 32,266 were nonusers. After adjustments for age, gender, Charlson Comorbidity Score, tobacco use, alcohol abuse/dependence, health care utilization and use of specific medication classes, statin use was associated with an increased incidence of common infections (odds ratio [OR]: 1.13; 95% confidence interval [CI]: 1.06-1.19) but not influenza or fungal infections (OR: 1.06, 95% CI: 0.80-1.39; OR: 0.97; 95% CI: 0.91-1.04, respectively). Time-to-first infection was similar in statin users and nonusers in all infection categories examined.

CONCLUSIONS

Statin use was associated with an increased incidence of common infections but not influenza or fungal infections. This study does not support a protective role of statins in infection prevention; however, the influence of potential confounders cannot be excluded.

Evidence for simvastatin anti-inflammatory actions based on quantitative analyses of NETosis and other inflammation/oxidation markers

Simvastatin (SMV) has been shown to exhibit promising anti-inflammatory properties alongside its classic cholesterol lowering action. We tested these emerging effects in a major thermal injury mouse model (3rd degree scald, ~20% TBSA) with previously documented, inflammation-mediated intestinal defects. Neutrophil extracellular traps (NETs) inflammation measurement methods were used alongside classic gut mucosa inflammation and leakiness measurements with exogenous melatonin treatment as a positive control. Our hypothesis is that simvastatin has protective therapeutic effects against early postburn gut mucosa inflammation and leakiness. To test this hypothesis, we compared untreated thermal injury (TI) adult male mice with TI littermates treated with simvastatin (0.2 mg/kg i.p., TI + SMV) immediately following burn injury and two hours before being sacrificed the day after; melatonin-treated (Mel) (1.86 mg/kg i.p., TI + Mel) mice were compared as a positive control. Mice were assessed for the following: (1) tissue oxidation and neutrophil infiltration in terminal ileum mucosa using classic carbonyl, Gr-1, and myeloperoxidase immunohistochemical or biochemical assays, (2) NETosis in terminal ileum and colon mucosa homogenates and peritoneal and fluid blood samples utilizing flow cytometric analyses of the surrogate NETosis biomarkers, picogreen and Gr-1, and (3) transepithelial gut leakiness as measured in terminal ileum and colon with FITC-dextran and transepithelial electrical resistance (TEER). Our results reveal that simvastatin and melatonin exhibit consistently comparable therapeutic protective effects against the following: (1) gut mucosa oxidative stress as revealed in the terminal ileum by markers of protein carbonylation as well as myeloperoxidase (MPO) and Gr-1 infiltration, (2) NETosis as revealed in the gut milieu, peritoneal lavage and plasma utilizing picogreen and Gr-1 flow cytometry and microscopy, and (3) transepithelial gut leakiness as assessed in the ileum and colon by FITC-dextran leakiness and TEER. Thus, simvastatin exhibits strong acute anti-inflammatory actions associated with marked decreases in gut tissue and systemic NETosis and decreased gut mucosa leakiness.

Bioactivity-guided isolation of anti-inflammation flavonoids from the stems of Millettia dielsiana Harms

Bioactivity-guided isolation of the EtOAc extract of the stems of Millettia dielsiana Harms yielded two new isoflavones together with nine known ones. Their structures were elucidated by analysis of the spectroscopic data including 2D NMR. All of the isolates were evaluated for their potential to inhibit the LPS-induced production of nitric oxide and TNF-α in murine macrophage RAW 264.7 cells. Among the tested compounds, Millesianin C (1) had the most potent anti-inflammatory effect decreasing NO production similar to that of dexamethasone and decreasing TNF-α secretion better than that of dexamethasone. Their structure-activity relationship was also analyzed.

Effect of statin use on outcomes of adults with candidemia

Background

Statins have immunomodulatory properties and hinder Candida growth. However, it is unknown whether they may improve prognosis in patients with candidemia. We sought to determine the effect of prior statin use on the clinical outcomes of patients suffering candidemia.

Methods and Findings

Multicenter cohort study of hospitalized adults with candidemia between 2005 and 2011 in six hospitals in Spain, Brazil and Argentina. Of 326 candidemias, 44 (13.5%) occurred in statin users and 282 (86.5%) in statin non-users. The median value of APACHE II at candidemia diagnosis was similar between groups (18 vs. 16; p=.36). Candida albicans was the most commonly isolated species, followed by C. parapsilosis, C. tropicalis, C. glabrata, and C. krusei. There were no differences regarding appropriate empirical antifungal treatment. Statin users had a lower early (5 d) case-fatality rate than non-users (4.5 vs. 17%; p=.031). This effect was not observed with other cardiovascular drugs (aspirin, beta blockers and ACE inhibitors). Independent factor related to early case-fatality rate was APACHE II score (AOR, 1.08; 95% CI, 1.03–1.14; p=.002). An appropriate empirical antifungal therapy (AOR, 0.11; 95% CI, 0.04–0.26; p=<.001) and prior statin use were independently associated with lower early case-fatality (AOR, 0.17; 95% CI, 0.03–0.93; p=.041). Fourteen days (14d) and overall (30d) case-fatality rates were similar between groups (27% vs. 29%; p=0.77 and 40% vs. 44%; p=.66).

Conclusions

The use of statins might have a beneficial effect on outcomes of patients with candidemia. This hypothesis deserves further evaluation in randomized trials.

Statins decrease mortality in Lebanese patients with sepsis: A multicenter study

BACKGROUND

Sepsis is a significant public health concern. The clinical response to statins is variable among sepsis patients.

OBJECTIVE

The aim of the study was to determinate the effect of statin-treatment on mortality in Lebanese patients with sepsis.

METHODS

A retrospective multicenter study on Lebanese patients with sepsis between January 2008 and March 2012 was conducted. Patients with a primary diagnosis of sepsis admitted to the intensive care unit of two tertiary care hospitals in Beirut were included. Patients who continued to receive statin therapy for dyslipidemia during the hospital course were included in the statin treatment group. The control group consisted of patients not taking statin. Demographic characteristics, clinical signs, standard laboratory test and treatment received were compared between these two groups using univariate analysis. Logistic regression and survival analysis were performed by SPSS.

RESULTS

THREE HUNDRED FIFTY ONE LEBANESE PATIENTS WERE INCLUDED (AGE: 71.33 SD=14.97 years; Male: 56%). Among them, 30% took a statin at the doses recommended for dyslipidemia. The comparison of the two groups showed that in the statin treatment group: The mean serum level of C-reactive protein at the time of sepsis was significantly decreased (P=0.050), the length-stay at ICU significantly increased (P=0.047) and mortality significantly reduced (P<0.001). Results were confirmed by logistic regression, particularly for mortality. In the Cox regression analysis, hypothermia and shock were significantly associated with high mortality while statin treatment decreased mortality (hazard ratio = 0.540; 95% CI: 0.302-0.964; P=0.037).

CONCLUSIONS

At usual doses for dyslipidemia, statin treatment decreased incidence of mortality related to sepsis and improved the survival in this Lebanese septic population. Large randomized controlled clinical trials must be realized to give conclusive results about the potential beneficial effect of statins in sepsis.

Prior statin therapy is associated with milder course and better outcome in acute pancreatitis--a cohort study

BACKGROUND

Statin treatment was shown to be associated with improved outcomes in several inflammatory conditions. We wanted to evaluate the effects of statin therapy on the course and outcome of acute pancreatitis (AP).

METHODS

A prospective cohort study included patients with acute pancreatitis divided into two groups according to statin use prior to hospitalization. Age, sex, etiology of AP, Ranson's score, APACHE II score and maximal CRP were recorded. Outcome measures were hospital length of stay and mortality. Matching of patients for matched analyses was done using individual matching and propensity score matching using variables a priori associated with course and outcome of acute pancreatitis.

RESULTS

Inclusion criteria were met for 1062 patients of whom 92 were taking statins. Statin users were older and had higher body mass indexes. Severe disease was more common in the no-statin group than in statin group (20.6% vs. 8.7% respectively). All severity markers were also higher in the no-statin group. All cause mortality was not different, while cardiovascular mortality was higher in the statin group in the cohort analysis. After matching by either method, the severity of disease was greater for the patients without statins treatment. Pancreatitis related mortality was higher in the no-statin group after matching. Among patients who developed severe AP, statin users showed lower Ranson's and APACHE II scores and lower maximal CRP.

CONCLUSIONS

Prior statin treatment significantly reduces morbidity and mortality in acute pancreatitis. Further studies are needed to evaluate possible therapeutic use of statins in acute pancreatitis.

Endothelial NOS (NOS3) impairs myocardial function in developing sepsis

Endothelial nitric oxide synthase (NOS)3-derived nitric oxide (NO) modulates inotropic response and diastolic interval for optimal cardiac performance under non-inflammatory conditions. In sepsis, excessive NO production plays a key role in severe hypotension and myocardial dysfunction. We aimed to determine the role of NOS3 on myocardial performance, NO production, and time course of sepsis development. NOS3(-/-) and C57BL/6 wildtype mice were rendered septic by cecum ligation and puncture (CLP). Cardiac function was analyzed by serial echocardiography, in vivo pressure and isolated heart measurements. Cardiac output (CO) increased to 160 % of baseline at 10 h after sepsis induction followed by a decline to 63 % of baseline after 18 h in wildtype mice. CO was unaltered in septic NOS3(-/-) mice. Despite the hyperdynamic state, cardiac function and mean arterial pressure were impaired in septic wildtype as early as 6 h post CLP. At 12 h, cardiac function in septic wildtype was refractory to catecholamines in vivo and respective isolated hearts showed impaired pressure development and limited coronary flow reserve. Hemodynamics remained stable in NOS3(-/-) mice leading to significant survival benefit. Unselective NOS inhibition in septic NOS3(-/-) mice diminished this survival benefit. Plasma NO( x )- and local myocardial NO( x )- and NO levels (via NO spin trapping) demonstrated enhanced NO( x )- and bioactive NO levels in septic wildtype as compared to NOS3(-/-) mice. Significant contribution by inducible NOS (NOS2) during this early phase of sepsis was excluded. Our data suggest that NOS3 relevantly contributes to bioactive NO pool in developing sepsis resulting in impaired cardiac contractility.

Systematic review and meta-analysis on the association between outpatient statins use and infectious disease-related mortality

BACKGROUND

To update and refine systematic literature review on the association between outpatient statins use and mortality in patients with infectious disease.

MATERIALS AND METHODS

We searched articles published before September 31, 2012, on the association between statins and infectious disease-related mortality through electronic databases. Eligible articles were analyzed in Review Manager 5.1. We conducted stratification analysis by study design, infection types, clinical outcomes and study locations.

RESULTS

The pooled odds ratio (OR) for death (statins use vs. no use) across the 41 included studies was 0.71 (95% confidence interval: 0.64, 0.78). The corresponding pooled ORs were 0.58 (0.38, 0.90), 0.66 (0.57, 0.75), 0.71 (0.57, 0.89) and 0.83 (0.67, 1.04) for the case-control study, retrospective cohort studies, prospective cohort studies and RCTs; 0.40 (0.20, 0.78), 0.61 (0.41, 0.90), 0.69 (0.62, 0.78) and 0.86 (0.68, 1.09) for bacteremia, sepsis, pneumonia and other infections; 0.62 (0.534, 0.72), 0.68 (0.53, 0.89), 0.71 (0.61, 0.83) and 0.86 (0.70, 1.07) for 30-day, 90-day, in-hospital and long-term (>1 year) mortality, respectively.

CONCLUSIONS

Outpatient statins use is associated with a lower risk of death in patients with infectious disease in observational studies, but in a less extent in clinical trials. This association also varies considerably by infection types and clinical outcomes.

The association of prior statin use in septic shock treated with early goal directed therapy

BACKGROUND

Previous literature suggests statins may have a therapeutic role in sepsis. No data have examined if statin use may have a positive impact beyond that afforded by early goal directed therapy (EGDT).

OBJECTIVE

To test the hypothesis that previous statin use is associated with improved clinically relevant outcomes in patients with severe sepsis and septic shock receiving EGDT.

METHODS

Retrospective cohort study of 91 patients who presented in an academic center in severe sepsis or septic shock and received EGDT. Primary outcome was mortality and secondary outcomes included mechanical ventilation days, ICU length of stay, and hospital length of stay.

RESULTS

Patients (87 of 91) presented to the Emergency Department before ICU admission. Patients (18 of 91) were receiving statin therapy before presentation. The statin group had a mortality rate of 22.2 vs. 39.7% in the nonstatin group (P=0.273). The statin group had fewer mechanical ventilation days (8.49 vs. 7.29 days, P=0.026), and a trend in improved hospital length of stay (17.9 vs. 14.4 days, P=0.065), and ICU length of stay (7.15 vs. 4.89 days, P=0.077).

CONCLUSION

Prior statin use is associated with fewer mechanical ventilation days and a trend toward improvement in other clinically relevant outcomes. This trial is limited by its retrospective nature and small sample size. These results should serve as hypothesis generating for future prospective trials, as the lack of novel drug therapy and the mortality rate of septic shock both remain unacceptable.

Reactive oxygen and nitrogen species in sepsis-induced hepatic microvascular dysfunction

Objective and design

Hepatic microvascular dysfunction is a critical event in the development of liver failure during sepsis. Activated blood cells and reactive oxygen and nitrogen species (RONS) have been implicated in the pathogenesis of sepsis.

Methods

Intravital-videomicroscopy was used to determine whether RONS contribute to the recruitment of leukocytes/platelets in the hepatic microvasculature during sepsis. Six hours following cecal-ligation and puncture (CLP), disturbances of the hepatic microvasculature were assessed in WT-mice (C57Bl/6 J; n = 8), in mice lacking gp91^phox(n = 5), overexpressing superoxide-dismutase (SOD, n = 8), in WT-mice treated with a NOS-inhibitor (l-NAME, n = 5), lacking nNOS, eNOS or iNOS (n = 5 each), treated with the NO-donor DetaNO (n = 5), in WT-mice treated with gadolinium-chloride (GdCl₂, n = 5) and compared to a group of WT-mice following a sham operation (n = 8). Six hours post-CLP, the adhesion of leukocytes and platelets in terminal hepatic venules (THV) and sinusoids was quantified.

Results

In WT-mice, CLP elicited increases in the number of adherent leukocytes and platelets. Similar responses to CLP were noted in mice overexpressing SOD or lacking either eNOS or gp91^phox. The blood-cell recruitment was significantly blunted in septic iNOS-knockout mice and this response was reversed by pre-treatment with DetaNO.

Conclusion

These findings suggest that iNOS-derived NO is a determinant of the pro-inflammatory phenotype assumed by the hepatic microvasculature during sepsis.

Predictors of hospital-acquired urinary tract-related bloodstream infection

OBJECTIVE

Bloodstream infection (BSI) secondary to nosocomial urinary tract infection is associated with substantial morbidity, mortality, and additional financial costs. Our objective was to identify predictors of nosocomial urinary tract-related BSI.

DESIGN

Matched case-control study.

SETTING

Midwestern tertiary care hospital.

PATIENTS

Cases (n=298) were patients with a positive urine culture obtained more than 48 hours after admission and a blood culture obtained within 14 days of the urine culture that grew the same organism. Controls (n=667), selected by incidence density sampling, included patients with a positive urine culture who were at risk for BSI but did not develop one. Methods. Conditional logistic regression and classification and regression tree analyses.

RESULTS

The most frequently isolated microorganisms that spread from the urinary tract to the bloodstream were Enterococcus species. Independent risk factors included neutropenia (odds ratio [OR], 10.99; 95% confidence interval [CI], 5.78-20.88), renal disease (OR, 2.96; 95% CI, 1.98-4.41), and male sex (OR, 2.18; 95% CI, 1.52-3.12). The probability of developing a urinary tract-related BSI among neutropenic patients was 70%. Receipt of immunosuppressants (OR, 1.53; 95% CI, 1.04-2.25), insulin (OR, 4.82; 95% CI, 2.52-9.21), and antibacterials (OR, 0.66; 95% CI, 0.44-0.97) also significantly altered risk.

CONCLUSIONS

The heightened risk of urinary tract-related BSI associated with several comorbid conditions suggests that the management of nosocomial bacteriuria may benefit from tailoring to certain patient subgroups. Consideration of time-dependent risk factors, such as medications, may also help guide clinical decisions in reducing BSI.

The impact of statin use on pneumonia risk and outcome: a combined population-based case-control and cohort study

Introduction

The impact of statin use on pneumonia risk and outcome remains unclear. We therefore examined this risk in a population-based case-control study and did a 5-year update of our previous 30-day mortality analyses.

Methods

We identified 70,953 adults with a first-time hospitalization for pneumonia between 1997 and 2009 in Northern Denmark. Ten age- and sex-matched population controls were selected for each pneumonia patient. To control for potential confounders, we retrieved individual-level data on other medications, comorbidities, recent surgery, socioeconomic indicators, influenza vaccination, and other markers of frailty or health awareness from medical databases. We followed all pneumonia patients for 30 days after hospital admission.

Results

A total of 7,223 pneumonia cases (10.2%) and 64 523 controls (9.1%) were statin users before admission, corresponding to an age- and sex-matched odds ratio (OR) of 1.17 (95% confidence interval [CI]: 1.14-1.21). After controlling for higher comorbidity and a wide range of other potential confounders, the adjusted OR for pneumonia associated with current statin use dropped to 0.80 (95% CI: 0.77-0.83). Previous statin use was not associated with decreased pneumonia risk (adjusted OR = 0.97, 95% CI: 0.91-1.02). Decreased risk remained significant after further adjustment for frailty and health awareness markers.

The prevalence of statin use among Danish pneumonia patients increased from 1% in 1997 to 24% in 2009. Thirty-day mortality following pneumonia hospitalization was 11.3% among statin users versus 15.1% among nonusers. This corresponded to a 27% reduced mortality rate (adjusted hazard ratio = 0.73, 95% CI: 0.67-0.79), corroborating our earlier findings.

Conclusions

Current statin use was associated with both a decreased risk of hospitalization for pneumonia and lower 30-day mortality following pneumonia.

The impact of prior long-term versus short-term statin use on the mortality of bacteraemic patients

BACKGROUND

The aim of this investigation was to assess the effect of prior statin use on the 30-day in-hospital mortality among bacteraemic patients and to determine the impact of long-term versus short-term statin use on the mortality of bacteraemic patients.

PATIENTS AND METHODS

A retrospective study of 342 bacteraemic patients who presented to the emergency department (ED) within a period of 7 years was undertaken. Twenty-three patients did not meet the inclusion criteria. The remaining 319 patients were divided into three groups according to statin use and duration of therapy prior to the bacteraemic episode: group 1 (n = 123) had long-term statin use ≥ 12 weeks, group 2 (n = 35) had short-term statin use < 12 weeks, and group 3 (n = 161) had no statin use.

RESULTS

The overall 30-day in-hospital all-cause mortality of patients with statins was lower than patients without statin therapy (13 vs. 24%, p = 0.001). The mortality rate in group 1 was lower than in group 2 (11 vs. 17%, p = 0.04). After adjusting for confounding variables, the results of a multiple Cox regression analysis revealed that the absence of statin use (hazard ratio [HR] = 2.98; 95% confidence interval [CI] 1.59-5.56, p = 0.001) was associated with increased 30-day in-hospital all-cause mortality in bacteraemic patients.

CONCLUSIONS

Statins reduce the 30-day in-hospital all-cause mortality of bacteraemic patients. Long-term statin use prior to the bacteraemia improves the survival of bacteraemic patients more than short-term statin use.

Clinical improvement in psoriasis with treatment of associated hyperlipidemia

Psoriasis is associated with an increased risk of cardiovascular disease, a principal cause of which is atherosclerosis caused by hyperlipidemia. However, it is not known whether treatment of hyperlipidemia in patients with psoriasis lead to clinical improvement in psoriasis condition. In this study, the authors summarize the existing literature relevant to this inquiry. They also describe the potential pathways believed to link psoriasis with atherosclerosis and the role of hyperlipidemia therapy in this setting. A few studies indicated clinical improvement in psoriasis with treatment of associated hyperlipidemia. Some studies showed that a low-fat diet improved psoriasis. Others indicated a decreased risk of psoriasis associated with intake of cholesterol-lowering drugs such as "statins." Treatment with statins increased lactate dehydrogenase level and diminished Psoriasis Area and Severity Index score, ie, reduced cutaneous lesion in psoriasis. Beneficial effects of statin therapy on psoriasis included downregulation of lymphocyte function-associated antigen-1, inhibition of leukocyte endothelial adhesion, extravasation and natural killer cell activity, inhibition of proinflammatory cytokines such as tumor necrosis factor-alpha and interleukin 1 and 6, lowering of C-reactive protein, promotion of a T(H)1 to T(H)2 cells and inhibition of T(H)1 cytokine receptors on T cells, leading to inhibition of activation of lymphocytes and infiltration into the inflammation sites. Taken together, current literature indicates clinical improvement in psoriasis condition with treatment of associated hyperlipidemia, particularly with statins of which the mechanisms could be attributed to immunomodulatory and anti-inflammatory effects.

Statins in prevention and treatment of severe sepsis and septic shock

Severe sepsis is an infection-induced inflammatory syndrome that can lead to multi-organ dysfunction and continues to be a major cause of morbidity and mortality worldwide. Because numerous cascades are triggered during sepsis, selective blocking of inflammatory mediators may be insufficient to arrest this process, and recent therapeutic approaches have proven controversial. Statins are the most commonly prescribed agents for hypercholesterolaemia and dominate the area of cardiovascular risk reduction. Moreover, these drugs have a variety of actions that are independent of their lipid lowering effect. Such anti-inflammatory, antioxidant, immunomodulatory, and antiapoptotic features have been collectively referred to as pleiotropic effects. By virtue of their pleiotropic effects, statins have also emerged as potentially useful in various critical care areas such as bacteraemia, the early phases of sepsis and septic shock, as well as the management of serious infections. This review outlines current evidence on the use of statins for preventing and treating sepsis.

Atorvastatin improves survival in septic rats: effect on tissue inflammatory pathway and on insulin signaling

The aim of the present study was to investigate whether the survival-improving effect of atorvastatin in sepsis is accompanied by a reduction in tissue activation of inflammatory pathways and, in parallel, an improvement in tissue insulin signaling in rats. Diffuse sepsis was induced by cecal ligation and puncture surgery (CLP) in male Wistar rats. Serum glucose and inflammatory cytokines levels were assessed 24 h after CLP. The effect of atorvastatin on survival of septic animals was investigated in parallel with insulin signaling and its modulators in liver, muscle and adipose tissue. Atorvastatin improves survival in septic rats and this improvement is accompanied by a marked improvement in insulin sensitivity, characterized by an increase in glucose disappearance rate during the insulin tolerance test. Sepsis induced an increase in the expression/activation of TLR4 and its downstream signaling JNK and IKK/NF-κB activation, and blunted insulin-induced insulin signaling in liver, muscle and adipose tissue; atorvastatin reversed all these alterations in parallel with a decrease in circulating levels of TNF-α and IL-6. In summary, this study demonstrates that atorvastatin treatment increased survival, with a significant effect upon insulin sensitivity, improving insulin signaling in peripheral tissues of rats during peritoneal-induced sepsis. The effect of atorvastatin on the suppression of the TLR-dependent inflammatory pathway may play a central role in regulation of insulin signaling and survival in sepsis insult.

Effect of preinjury statin use on mortality and septic shock in elderly burn patients

BACKGROUND

Premorbid statin use has been associated with decreased mortality in septic and trauma patients. This has been ascribed to the pleiotropic, anti-inflammatory effects of HMG-CoA reductase inhibitors. This association has not been investigated in burn victims.

METHODS

A retrospective review of 223 consecutive patients, aged 55 years and older admitted to Vanderbilt University Regional Burn Center from January 2006 to December 2008, was performed. Multivariate regression analysis determined odds ratios of death and sepsis by statin use, adjusting for cardiovascular comorbidities.

RESULTS

Of 223 patients, 70 (31.4%) were taking statins before admission. Mean age and mean total body surface area burn were not significantly different by statin use. The odds ratio of inhospital death was 0.17 (95% confidence interval 0.05-0.57; p = 0.004) if on statins. The odds ratio of mortality when stratified by cardiovascular comorbidities did not change. Sepsis developed in 30 patients (13.5%), with an odds ratio in statin users of 0.50 (95% confidence interval 0.20-1.30; p = 0.155).

CONCLUSION

Preinjury statin use was associated with an 83% reduction in the odds of death after thermal injury. The odds of sepsis decreased by 50%, although not statistically significant. Further study is warranted to investigate the potential benefits of statin therapy in the management of burn victims.