Simvastatin treatment improves survival in a murine model of burn sepsis: Role of interleukin 6

doi:10.1016/j.burns.2010.10.010

Burns

Volume 37, Issue 2, March 2011, Pages 222-226

https://doi.org/10.1016/j.burns.2010.10.010 Get rights and content

Abstract

Infection is the most common and most serious complication of a major burn related to burn size. Recent studies have demonstrated that statin treatment can decrease mortality in murine or human sepsis. In the current study mice were anesthetized and subjected to a dorsal 30% TBSA scald burn. Simvastatin or placebo were administered by intraperitoneal injection once daily or every 12 h. On post burn day 7 cecal ligation and puncture with a 21-gauge needle (CLP) was performed under ketamine/xylazine anesthesia, the two different dosing schedules were continued and survival was monitored. In other groups of mice, interleukin-6 (IL-6) levels in blood were measured in mice at 7 days after injury. A simvastatin dependent improvement in survival was observed in the burn sepsis model. This protection was found to be dose and time dependent. In addition, statin treatment reduced the elevation in IL-6 levels of mice burned 7 days previously. However, IL-6 levels in burned mice with or without statin treatment were elevated by CLP to the same degree. The results of these studies suggest that statin treatment reduces mortality in mice with burns and CLP and that this effect may not be mediated via IL-6 levels.

Introduction

Sepsis and septic shock are the tenth most common causes of death in the United States [1], [2]. Infection is the most common and most serious complication of a major burn related to burn size [1], [3]. Despite improvements in antimicrobial therapies, sepsis still accounts for 50–60% of deaths in burn patients. Sepsis in burn patients is commonly due to bronchopneumonia, pyelonephritis, thrombophlebitis, or invasive wound infection. The burn wound is an ideal media for bacterial growth and provides a wide portal for invasion. Microbial colonization of open burn wounds, primarily from endogenous sources, is usually established by the end of the first week after injury. Infection is further promoted by loss of the epithelial barrier, malnutrition induced by the hypermetabolic response to burns, and by a generalized post-burn immunosuppression.

Burn leads to suppression of nearly all aspects of the immune response [4], [5]. Granulocytopenia is commonly seen in burn patients. Blood levels of immunoglobulins, fibronectin, and complement are reduced, in combination with a diminished ability for opsonization, chemotaxis and phagocytosis and reduced killing function of neutrophils, monocytes and macrophages. The cellular immune response is also impaired, as evidenced by anergy to common antigens, altered lymphocyte mitogenesis, and mixed lymphocyte responsiveness [4], [5].

Burn also results in reductions of interleukin-2 (Il-2) production, T-cell and NK cell cytotoxicity, and helper to suppressor T-cell ratio (HSR) [4], [5]. Given the acute onset and unpredictable nature of sepsis, primary prevention is rarely attempted in its management. However, recent studies have demonstrated that statin treatment can decrease mortality is a murine model of sepsis by preservation of cardiac function and reversal of inflammatory alterations. In addition, it has been shown that treatment with statins is associated with reduced incidence of sepsis in patients [6], [7], [8], [9], [10], [11].

In the present study, we developed a murine model of sepsis in burned mice and demonstrated that Simvastatin treatment reduces mortality. We also examined IL-6 serum levels in burned mice with and without statin treatment, before and after CLP since it has been suggested that the level of IL-6 relates to the survival of burned patients with sepsis [21].

Section snippets

Burns

Male CD-1 mice weighing 25–28 g were purchased from Charles River Breeding Laboratories, Boston MA. Full-thickness, non-lethal thermal injury (30% total body surface area [TBSA]) was produced, as described previously [12] using a protocol approved by the Subcommittee on Research Animal Care of the Massachusetts General Hospital. Briefly, the mice were anesthetized with ether and their backs were shaved with animal hair clippers. Under ether anesthesia, they were placed in molds exposing 30% TBSA

Results

We then proceeded to examine the effect of burn and CLP. A schematic diagram of the study protocol is shown in Fig. 1. Fig. 2 illustrates, the effect of Simvastatin and placebo treatment on the survival of mice with full-thickness (30% TBSA) burn and sepsis produced by CLP at 7 days after burn; treatment with simvastatin and placebo was initiated 2 h after burn. In the animals treated at 12-h intervals, statistical analysis by the Log-Rank (Mantel-Cox) method demonstrated significantly greater

Discussion

Sepsis can be broadly defined as the presence of pus-forming bacteria or their toxins in the blood or tissues. Sepsis remains the leading cause of death in patients treated in intensive care units with mortality ranging from 30 to 70% [1], [2]. The present study was designed to address two questions: (1) Does statin treatment, which has been shown to ameliorate the increased mortality produced by CLP protect in the burn plus CLP murine model? (2) Does statin treatment effect the elevation of

Conclusions

The results of these studies suggest that statin treatment reduces mortality in mice with burn and CLP and that this effect may not be mediated via modulation of IL-6 levels. Future studies of the levels of other cytokines after burn and CLP are warranted.

Conflict of interest statement

None of the authors have financial and personal relationships with other people or organizations that could inappropriately influence (bias) this work.

Acknowledgments

This work was supported in part by grants from the National Institutes of Health (NIGMS P50 GM21000) and Shriners Hospitals for Children.

References (22)

S.T. O'Sullivan et al.
Immunosuppression following thermal injury: the pathogenesis of immunocysfunction
Br J Plastic Surg
(1997)
M.G. Schwacha et al.
Differential expression and tissue compartmentalization of the inflammatory responses following thermal injury
Cytokine
(2002)
D.G. Hackam et al.
Statins and sepsis in patients with cardiovascular disease: a population-based cohort analysis
Lancet
(2006)
E.A. Carter et al.
Injury-induced inhibition of small intestinal protein and nucleic acid synthesis
Gastroenterology
(1990)
G.S. Martin et al.
The epidemiology of sepsis in the United States from 1979 through 2000
N Engl J Med
(2003)
R.S. Hotchkiss et al.
The pathophysiology and treatment of sepsis
N Engl J Med
(2003)
B.A. Pruitt
Infection and the burn patient
Br J Surg
(1990)
E.M. Mortensen et al.
The effect of prior statin use on 30-day mortality for patients hospitalized with community-acquired pneumonia
Respir Res
(2005)
P. Kruger et al.
Statin therapy is associated with fewer deaths in patients with bacteraemia
Intensive Care Med
(2006)
Y. Almog et al.
Prior statin therapy is associated with a decreased rate of severe sepsis
Circulation
(2004)

Y. Almog et al.

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

Crit Care Med

(2007)

Cited by (31)

Adenosine diphosphate ribosylation factor 6 inhibition protects burn sepsis induced lung injury through preserving vascular integrity and suppressing ASC inflammasome transmission
2024, Burns
Severe burns are devastating injuries with significant immune dysfunction and result in substantial mortality and morbidity due to sepsis induced organ failure. Acute lung injury is the most common type of organ injury in sepsis, however, the mechanisms of which are poorly understood and effective therapeutic measures are limited. This study is aimed to investigate the effect of a small Guanosine triphosphatase (GTPase), Adenosine diphosphate ribosylation factor 6 (ARF6), on burn sepsis induced lung injury, and discuss the possible mechanisms.
Burn sepsis was established in male C57BL/6 mice. Mice were anesthetised by intramuscular injection of ketamine and xylazine hydrochloride, then 30% TBSA full thickness burn followed by sub-eschar injection of lipopolysaccharide. Animals were treated with intraperitoneal injection of a small molecule inhibitor of ARF6: NAV-2729, or vehicle, right after the burn and sepsis stimuli were inflicted. Lung tissues were harvested for histopathological observation and the acute lung injury scores were calculated. Organ permeability, Vascular Endothelial Cadherin (VE-cadherin) expression, inflammatory cytokine levels and myeloperoxidase activity in lung tissues were detected. Rat pulmonary microvascular endothelial cells (PMVECs) were stimulated by burn sepsis serum with or without 10 μM NAV-2729. The ARF6 activation, VE-cadherin expression, inflammasome activity, adapter protein apoptosis speck-like protein containing a caspase recruiting domain (ASC) specks and cytokines secretion were determined. Student’s t test was used for comparison between two groups. Multiple comparisons among groups were performed by using analysis of variance, with Tukey’s test for the post hoc test.
NAV-2729 treatment attenuated burn sepsis induced lung injury and promoted survival of burn septic mice by preserving VE-cadherin expression in endothelial cell adherent junction and limited vascular hyperpermeability in lung tissues. Moreover, inflammatory cytokine expression and inflammatory injury in lung tissues were alleviated. Mechanistically, NAV-2729 enhanced vascular integrity by inhibiting ARF6 activation and restoring VE-cadherin expression in PMVECs. In addition, NAV-2729 inhibited ARF6-dependent phagocytosis of ASC specks, thus preventing inflammation propagation mediated by cell-to-cell transmission of ASC specks.
ARF6 inhibition preserved vascular integrity by restoring expression of VE-cadherin and suppressed the spread of inflammation by affecting phagocytosis of ASC specks, thus protected against sepsis induced lung injury and improve survival of burn septic animals. The findings of this study implied potential therapeutics by which ARF6 inhibition can protect lung function from septic induced lung injury and improve outcomes in burn sepsis.
Safety profile of atorvastatin in the role of burn wound injury conversion
2020, American Journal of Surgery
Citation Excerpt :
Furthermore, it was postulated that atorvastatin promotes earlier transition from the inflammatory to the proliferative phase and stimulates a faster resolution of myofibroblasts. Additional studies have also shown that statins were able to protect mice with burn injury from liver injury by suppressing the TNF-alpha signaling pathway as well as to improve survival in burn-related sepsis in the murine model.8,9 Atorvastatin has yet to be studied in human burn patients, and we believe that studying the safety of administration of atorvastatin to patients with burn injuries is imperative prior to beginning any such experiments due to potential side-effects of liver injury and rhabdomyolysis.
Atorvastatin could be beneficial in the treatment of burn patients to prevent burn wound progression from partial to full thickness. Our primary aim is to evaluate the safety of atorvastatin in burn patients.
Single center retrospective chart review of burn patients receiving atorvastatin during admission May 2016–May 2019 with historic controls was performed. Demographics, burn total body surface area, atorvastatin doses, creatinine phosphokinase, aspartate aminotransferase levels and adverse events were analyzed.
48 burn patients received atorvastatin during admission. Nine patients experienced elevated CK or AST levels during admission, but did not correlate with timing of atorvastatin administration and were comparable to levels in control patients. No adverse events associated with atorvastatin were identified.
Atorvastatin administered to patients with burn injuries was not associated with any adverse events or attributable lab abnormalities. We believe that atorvastatin is safe to use in patients with burns and can be safely studied to determine the drug’s effect on the prevention of burn wound conversion.
Oral administration of yeast β-glucan ameliorates inflammation and intestinal barrier in dextran sodium sulfate-induced acute colitis
2017, Journal of Functional Foods
Citation Excerpt :
IL-6 is produced by various cell types and exerts pleiotropic effects on different organ systems. Alterations in the production of IL-6 have been found in inflammatory states such as rheumatoid arthritis (Polgar et al., 2000), Crohn's disease, UC (Reinisch et al., 1999), and sepsis (Beffa et al., 2011). IL-6 can stimulate neutrophil chemotaxis and leads to tissue destruction in the colon.
Ulcerative colitis is a chronic inflammatory disease that is characterized by relapsing inflammation and dysfunction within the gastrointestinal tract. The purpose of this study was to investigate the protective effects of yeast β-glucan on regulating inflammation and disruption of the epithelial barrier in colitis caused by dextran sulfate sodium (DSS). Oral administration of yeast β-glucan reduced clinical symptoms, inflammatory infiltrates and cell apoptosis in the colon epithelium, ameliorated intestinal permeability and the structural integrity of tight junctions. Moreover, treatment with yeast β-glucan not only decreased myeloperoxidase, eosinophil peroxidase and N-acetyl-β-d-glucosaminidase levels, but also modified the immune status characterized by the change in immunoglobulin levels in DSS-treated mice. These results suggest that yeast β-glucan improves DSS-induced changes in mucosal inflammatory lesions and the intestinal barrier by inhibiting the expression of inflammatory mediators and enhancing the expression of tight junction proteins associated with intestinal permeability.
Protective effects of simvastatin administered in the experimental hepatic ischemia-reperfusion injury rat model
2015, Journal of Surgical Research
Citation Excerpt :
The rats were treated with i.p. injections of 1 mL of ethanol:saline (1:2, vehicle) 60 min before the laparotomy. Group III (I/R 2.5 mg/kg SV) was treated similarly to the I/R group, but also received i.p. injections of 1 mL of 2.5 mg/kg SV, 60 min before the I/R [8]. Group IV (I/R 5.0 mg/kg SV) was treated similarly to group III rats but received 1 mL of 5.0-mg/kg SV.
Hepatic ischemia–reperfusion (I/R) injury is a major complication in clinical practice. Previous studies suggest that statins have pleiotropic effects in addition to cholesterol-lowering effects. In this study, we aimed to investigate the hepatoprotective role of two different doses of simvastatin (SV) pretreatment in rats with experimental hepatic I/R injury.
Adult male Sprague–Dawley rats were divided into four groups (n = 7 in each group) :control, I/R, I/R with 2.5-mg/kg SV, and I/R with 5.0-mg/kg SV. Before hepatic I/R was induced, SV was injected intraperitoneally at doses of 2.5 and 5.0 mg/kg. After 45-min ischemia and a 60-min reperfusion period, the animals were euthanized, and liver tissues were excised. Tissue levels of malondialdehyde and nitric oxide, and activities of superoxide dismutase, glutathione peroxidase, and catalase were measured. Liver tissues were also evaluated histopathologically and immunohistochemically.
Histopathologic evaluation showed that 5.0-mg/kg SV reduced hepatic damage and apoptosis. Pretreatment with 5.0-mg/kg SV reduced malondialdehyde and nitric oxide levels (P < 0.01) and increased superoxide dismutase, glutathione peroxidase, and catalase activities significantly (P < 0.001, P < 0.01) in I/R with 2.5-mg/kg SV compared with I/R group. In addition, SV decreased Kupffer cell activation, and hypoxia-inducible factor-1α and vascular endothelial growth factor protein levels.
The results of this study suggest that 5.0-mg/kg SV pretreatment may be protective against hepatic I/R injury. This effect can be achieved by antioxidant and antiapoptotic activities.
δ-Amyrone inhibits lipopolysaccharide-induced inflammatory cytokines and protects against endotoxic shock in mice
2015, Chemico-Biological Interactions
Citation Excerpt :
IL-6, another crucial pro-inflammatory cytokine participating in inflammation, is produced by various cell types and exerts pleiotropic effects on different organ systems. Changed IL-6 production has been found in inflammatory states such as sepsis [26]. NO is a short-lived small molecule which plays a crucial role in various physiological processes.
δ-Amyrone (13(18)-Oleanen-3-one), which is an active constituent extracted and separated from Sedum lineare Thunb., has been found to possess a potent anti-inflammatory effect in different inflammation model animals. But its effects on lipopolysaccharide (LPS)-induced endotoxic shock have not been previous explored. The aim of this study is to evaluate the effect of δ-Amyrone on LPS-induced inflammatory cytokines and the protective effect on endotoxic shock mice. Experimental animals received δ-amyrone (4 and 8 mg/kg, i.p.) and dexamethasone (DEX) (5 mg/kg, i.p.) at 24 and 1 h before LPS injection. δ-Amyrone treatment significantly decreased mortality rate, tissues myeloperoxodase (MPO) activity, p65 NF-κB protein expression when compared with the LPS groups. The levels of tumor nectosis factor-alphagene (TNF-α) and interleukin-6 (IL-6) both in serum and lung, liver, kidney tissues, as well as the accumulation of nitric oxide (NO) in serum were decreased by δ-amyrone in response to p65 nuclear factors-kappa B (NF-κB). These results suggest that the protective activity of δ-amyrone on LPS-induced endotoxic shock is attributed to reducing NO production and mediating the pro-inflammatory cytokines, inhibited NF-κB expression.
Defining Traumatic Injury as a Disease
2014, Pathobiology of Human Disease: A Dynamic Encyclopedia of Disease Mechanisms
Traumatic injuries induce a complex response that disrupts physiological and immune system homeostasis. Trauma-induced loss of homeostasis can predispose people to infections and other complications such as coagulopathy, organ dysfunction, and metabolic disturbance. The response to injuries varies considerably by type and severity as well as by individual variables such as age, sex, and genetics. These variables make trauma research a challenging area of investigation. Nevertheless, advances have been made in understanding how injuries influence the immune system and other vital organs. This article provides an overview of current knowledge about how traumatic injuries induce disease by affecting host immune system function. The idea that traumatic injuries induce a unique host response that may be triggered by a combination of danger signals including danger-associated molecular pattern molecules, self-antigens, and cytokines is presented and discussed. Additionally, we present potential treatment approaches that might be useful strategies for restoring immune system and physiological homeostasis following traumatic injuries.

View all citing articles on Scopus

View full text

Simvastatin treatment improves survival in a murine model of burn sepsis: Role of interleukin 6

Abstract

Introduction

Section snippets

Burns

Results

Discussion

Conclusions

Conflict of interest statement

Acknowledgments

Br J Plastic Surg

Cytokine

Lancet

Gastroenterology

The epidemiology of sepsis in the United States from 1979 through 2000

N Engl J Med

The pathophysiology and treatment of sepsis

N Engl J Med

Infection and the burn patient

Br J Surg

The effect of prior statin use on 30-day mortality for patients hospitalized with community-acquired pneumonia

Respir Res

Statin therapy is associated with fewer deaths in patients with bacteraemia

Intensive Care Med

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

Circulation

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

Crit Care Med