Effects of low-dose acetylsalicylic acid and atherosclerotic vascular diseases on the outcome in patients with severe sepsis or septic shock

Metabolic syndrome induces benefits in mice experiencing severe sepsis, comparable to the effects of low-dose aspirin pretreatment in septic mice lacking metabolic syndrome

BACKGROUND

Sepsis is a complex condition characterized by systemic host inflammation caused by an infection. Experimental and observational studies indicate that obesity, one of the components of metabolic syndrome (MetS), or aspirin (ASA) treatment could be associated with sepsis survival. However, the effects of ASA on septic mice with MetS-induced conditions have not been explored.

METHODS

Swiss mice were administered monosodium glutamate (MSG) (4 mg/kg) during their first 5 days of life for MetS induction, while the control mice received an equimolar saline solution. MetS was validated in male mice on their 60th day of life. ASA treatment was administered for 15 days prior to sepsis (40 mg/kg). On the 75th day, sepsis was induced in MetS and control mice through cecal ligation and puncture (CLP). The effects of ASA on septic mice with MSG-induced MetS were assessed by determining survival rates, quantification of nitric oxide (NO), and cytokine levels in the plasma, while correlating these data with hematological, blood glucose and cardiovascular parameters.

RESULTS

MetS was validated by Lee-Index (3 body weight/naso-anal length×1000), hypertension, and hyperglycemia in animals receiving MSG as neonates. In control animals, severe sepsis promoted hypoglycemia, which was associated with mortality, as well as increased plasma NO levels, hypotension, hematological alterations, and elevation of proinflammatory cytokines. In contrast, MetS and pre-treatment with ASA were able to prevent sepsis-related alterations.

CONCLUSIONS

MetS and ASA pre-treatment provided protection against severe sepsis. However, ASA was ineffective in mice with MetS undergoing severe sepsis.

Impact of P2Y12 inhibitors on clinical outcomes in sepsis-3 patients receiving aspirin: a propensity score matched analysis

BACKGROUND

Sepsis is a life-threatening disease accompanied by disorders of the coagulation and immune systems. P2Y12 inhibitors, widely used for arterial thrombosis prevention and treatment, possess recently discovered anti-inflammatory properties, raising potential for improved sepsis prognosis.

METHOD

We conducted a retrospective analysis using the data from Medical Information Mart for Intensive Care-IV database. Patients were divided into an aspirin-alone group versus a combination group based on the use of a P2Y12 inhibitor or not. Differences in 30-day mortality, length of stay (LOS) in intensive care unit (ICU), LOS in hospital, bleeding events and thrombotic events were compared between the two groups.

RESULT

A total of 1701 pairs of matched patients were obtained by propensity score matching. We found that no statistically significant difference in 30-day mortality in aspirin-alone group and combination group (15.3% vs. 13.7%, log-rank p = 0.154). In addition, patients received P2Y12 inhibitors had a higher incidence of gastrointestinal bleeding (0.5% vs. 1.6%, p = 0.004) and ischemic stroke (1.7% vs. 2.9%, p = 0.023), despite having a shorter LOS in hospital (11.1 vs. 10.3, days, p = 0.043). Cox regression showed that P2Y12 inhibitor was not associated with 30-day mortality (HR = 1.14, 95% CI 0.95-1.36, p = 0.154).

CONCLUSION

P2Y12 inhibitors did not provide a survival benefit for patients with sepsis 3 and even led to additional adverse clinical outcomes.

Association between aspirin and mortality in critically ill patients with atrial fibrillation: a retrospective cohort study based on mimic-IV database

Background

Atrial fibrillation (AF) is a prevalent issue among critically ill patients, and the availability of effective treatment strategies for AF is limited.

Aim

The objective of this study was to evaluate the mortality rate associated with AF in critically ill patients who were either aspirin or non-aspirin users.

Methods

This cohort study incorporated critically ill patients with AF from the Medical Information Mart for Intensive Care database. The study compared incidences of 28-day mortality, 90-day mortality, and 1-year mortality between patients with and without aspirin prescriptions. To assess the association between aspirin and the endpoints, Kaplan-Meier analysis and Cox proportional hazards regression analyses were conducted.

Results

In this study, a total of 13,330 critically ill patients with atrial fibrillation (AF) were included, of which 4,421 and 8,909 patients were categorized as aspirin and non-aspirin users, respectively. The 28-day, 90-day, and 1-year mortality rates were found to be 17.5% (2,330/13,330), 23.9% (3,180/13,330), and 32.9% (4,379/13,330), respectively. The results of a fully-adjusted Cox proportional hazard model indicated that aspirin use was negatively associated with the risk of death after adjusting for confounding factors (28-day mortality, HR 0.64, 95% CI 0.55-0.74; 90-day mortality, HR 0.65, 95% CI 0.58-0.74; 1-year mortality, HR 0.67, 95%CI 0.6∼0.74). The results of the subgroup analysis indicate a more robust correlation, specifically among patients under the age of 65 and those without a history of congestive heart failure or myocardial infarction.

Conclusions

The utilization of aspirin may exhibit a correlation with a reduction in risk-adjusted mortality from all causes in critically ill patients diagnosed with atrial fibrillation. However, additional randomized controlled trials are necessary to elucidate and confirm this potential association.

Continuation of chronic antiplatelet therapy is not associated with increased need for transfusions: a cohort study in critically ill septic patients

BACKGROUND

The decision to maintain or halt antiplatelet medication in septic patients admitted to intensive care units presents a clinical dilemma. This is due to the necessity to balance the benefits of preventing thromboembolic incidents and leveraging anti-inflammatory properties against the increased risk of bleeding.

METHODS

This study involves a secondary analysis of data from a prospective cohort study focusing on patients diagnosed with severe sepsis or septic shock. We evaluated the outcomes of 203 patients, examining mortality rates and the requirement for transfusion. The cohort was divided into two groups: those whose antiplatelet therapy was sustained (n = 114) and those in whom it was discontinued (n = 89). To account for potential biases such as indication for antiplatelet therapy, propensity score matching was employed.

RESULTS

Therapy continuation did not significantly alter transfusion requirements (discontinued vs. continued in matched samples: red blood cell concentrates 51.7% vs. 68.3%, p = 0.09; platelet concentrates 21.7% vs. 18.3%, p = 0.82; fresh frozen plasma concentrates 38.3% vs. 33.3%, p = 0.7). 90-day survival was higher within the continued group (30.0% vs. 70.0%; p < 0.001) and the Log-rank test (7-day survivors; p = 0.001) as well as Cox regression (both matched samples) suggested an association between continuation of antiplatelet therapy < 7 days and survival (HR: 0.24, 95%-CI 0.10 to 0.63, p = 0.004). Sepsis severity expressed by the SOFA score did not differ significantly in matched and unmatched patients (both p > 0.05).

CONCLUSIONS

The findings suggest that continuing antiplatelet therapy in septic patients admitted to intensive care units could be associated with a significant survival benefit without substantially increasing the need for transfusion. These results highlight the importance of a nuanced approach to managing antiplatelet medication in the context of severe sepsis and septic shock.

The 125th Anniversary of Aspirin-The Story Continues

The year 2024 marks the 125th anniversary of aspirin, still one of the most frequently used drugs worldwide. Despite its veritable age, it is still relevant in pharmacotherapy and its use has spread to new areas over time. Due to aspirin's multiple pharmacological actions unified in one single molecule (i.e., analgesic, antipyretic, anti-inflammatory, antithrombotic, and antiviral effects), it continues to attract considerable attention in the scientific community and is subject to intense basic and clinical research. In fact, recent results confirmed aspirin's potential role as an antiviral drug and as an agent that can block harmful platelet functions in inflammatory/immunological processes. These features may open up new horizons for this ancient drug. The future of aspirin looks, therefore, bright and promising. Aspirin is not yet ready for retirement; on the contrary, its success story continues. This 125th anniversary paper will concisely review the various therapeutic uses of aspirin with a particular emphasis on the latest research results and their implications (e.g., use as an antiviral agent). In addition, the reader is provided with future perspectives for this remarkable drug.

The role of platelet P2Y12 receptors in inflammation

Inflammation is a complex pathophysiological process underlying many clinical conditions. Platelets contribute to the thrombo-inflammatory response. Platelet P2Y12 receptors amplify platelet activation, potentiating platelet aggregation, degranulation and shape change. The contents of platelet alpha granules, in particular, act directly on leucocytes, including mediating platelet-leucocyte aggregation and activation via platelet P-selectin. Much evidence for the role of platelet P2Y12 receptors in inflammation comes from studies using antagonists of these receptors, such as the thienopyridines clopidogrel and prasugrel, and the cyclopentyltriazolopyrimidine ticagrelor, in animal and human experimental models. These suggest that antagonism of P2Y12 receptors decreases markers of inflammation with some evidence that this reduces incidence of adverse clinical sequelae during inflammatory conditions. Interpretation is complicated by pleiotropic effects such as those of the thienopyridines on circulating leucocyte numbers and of ticagrelor on adenosine reuptake. The available evidence suggests that P2Y12 receptors are prominent mediators of inflammation and P2Y12 receptor antagonism as a potentially powerful strategy in a broad range of inflammatory conditions. LINKED ARTICLES: This article is part of a themed issue on Platelet purinergic receptor and non-thrombotic disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.4/issuetoc.

Management of patients on antithrombotic therapy with severe infections: a joint clinical consensus statement of the ESC Working Group on Thrombosis, the ESC Working Group on Atherosclerosis and Vascular Biology, and the International Society on Thrombosis and Haemostasis

Patients with severe infections and a pre-existing indication for antithrombotic therapy, i.e. antiplatelet agents, anticoagulant drugs, or their combinations, require integrated clinical counselling among coagulation, infectious disease, and cardiology specialists, due to sepsis-induced coagulopathy that frequently occurs. Bacterial and viral pathogens constitute an increasing threat to global public health, especially for patients with ongoing antithrombotic treatment who have a high risk of thrombotic recurrences and high susceptibility to severe infections with increased morbidity and mortality. Similarly, sepsis survivors are at increased risk for major vascular events. Coagulopathy, which often complicates severe infections, is associated with a high mortality and obligates clinicians to adjust antithrombotic drug type and dosing to avoid bleeding while preventing thrombotic complications. This clinical consensus statement reviews the best available evidence to provide expert opinion and statements on the management of patients hospitalized for severe bacterial or viral infections with a pre-existing indication for antithrombotic therapy (single or combined), in whom sepsis-induced coagulopathy is often observed. Balancing the risk of thrombosis and bleeding in these patients and preventing infections with vaccines, if available, are crucial to prevent events or improve outcomes and prognosis.

Association Between Aspirin Use and Sepsis Outcomes: A National Cohort Study

BACKGROUND

Aspirin has anti-inflammatory and antiplatelet activities and directly inhibits bacterial growth. These effects of aspirin may improve survival in patients with sepsis. We retrospectively reviewed a large national health database to test the relationship between prehospital aspirin use and sepsis outcomes.

METHODS

We conducted a retrospective population-based cohort study using the National Health Insurance Research Database of Taiwan from 2001 to 2011 to examine the relationship between aspirin use before hospital admission and sepsis outcomes. The association between aspirin use and 90-day mortality in sepsis patients was determined using logistic regression models and weighting patients by the inverse probability of treatment weighting (IPTW) with the propensity score. Kaplan-Meier survival curves for each IPTW cohort were plotted for 90-day mortality. For sensitivity analyses, restricted mean survival times (RMSTs) were calculated based on Kaplan-Meier curves with 3-way IPTW analysis comparing current use, past use, and nonuse.

RESULTS

Of 52,982 patients with sepsis, 12,776 took aspirin before hospital admission (users), while 39,081 did not take any antiplatelet agents including aspirin before hospital admission (nonusers). After IPTW analysis, we found that when compared to nonusers, patients who were taking aspirin within 90 days before sepsis onset had a lower 90-day mortality rate (IPTW odds ratio [OR], 0.90; 95% confidence interval [CI], 0.88-0.93; P < .0001). Based on IPTW RMST analysis, nonusers had an average survival of 71.75 days, while current aspirin users had an average survival of 73.12 days. The difference in mean survival time was 1.37 days (95% CI, 0.50-2.24; P = .002).

CONCLUSIONS

Aspirin therapy before hospital admission is associated with a reduced 90-day mortality in sepsis patients.

Oxygen therapy for sepsis and prevention of complications

Patients with sepsis have a wide range of respiratory disorders that can be treated with oxygen therapy. Experimental data in animal sepsis models show that oxygen therapy significantly increases survival, while clinical data on the use of different oxygen therapy protocols are ambiguous. Oxygen therapy, especially hyperbaric oxygenation, in patients with sepsis can aggravate existing oxidative stress and contribute to the development of disseminated intravascular coagulation. The purpose of this article is to compare experimental and clinical data on oxygen therapy in animals and humans, to discuss factors that can influence the results of oxygen therapy for sepsis treatment in humans, and to provide some recommendations for reducing oxidative stress and preventing disseminated intravascular coagulation during oxygen therapy.

Transfusion of fresh washed platelets does not prevent experimental polymicrobial-induced septic shock in mice

INTRODUCTION

The specific role of platelets during sepsis is not yet fully understood, probably related to the paradox of platelets being potentially beneficial but also deleterious via their thrombotic functions.

OBJECTIVE

To evaluate the impact of thrombocytopenia on septic shock in mice and to investigate whether transfusion of fresh washed platelets, either fully functional or with impaired hemostatic properties, might have beneficial effects.

METHODS

Septic shock was induced by cecal ligation and puncture (CLP). Experimental depletion of circulating platelets was induced with a rat anti-mouse GPIbα monoclonal antibody. Transfusion of either wild-type washed platelets, platelets treated with the antiplatelet drugs acetylsalicylic acid (ASA) and clopidogrel, or GPIIbIIIa-deficient washed platelets treated with ASA and clopidogrel was performed 4 h after CLP surgery.

RESULTS

Depletion of circulating platelets negatively affected septic shock, worsening systemic inflammation, coagulopathy, organ damage, and mortality, raising the question of whether a higher platelet count could be protective. Transfusion of fully functional platelets or platelets with combined treatment with ASA and clopidogrel, with or without additional GPIIbIIIa deficiency, afforded an immediate return of circulating platelet counts to their initial values before surgery. However, transfusion of each of the three types of platelets did not prevent arterial hypotension, inflammatory response, coagulopathy, and organ damage during septic shock.

CONCLUSION

Depletion of circulating platelets negatively affects septic shock, while transfusion of washed platelets has no significant beneficial effect in mice.

Combined Antiplatelet Therapy Reduces the Proinflammatory Properties of Activated Platelets

The cause of atherothrombosis is rupture or erosion of atherosclerotic lesions, leading to an increased risk of myocardial infarction or stroke. Here, platelet activation plays a major role, leading to the release of bioactive molecules, for example, chemokines and coagulation factors, and to platelet clot formation. Several antiplatelet therapies have been developed for secondary prevention of cardiovascular events, in which anticoagulant drugs are often combined. Besides playing a role in hemostasis, platelets are also involved in inflammation. However, it is unclear whether current antiplatelet therapies also affect platelet immune functions. In this study, the possible anti-inflammatory effects of antiplatelet medications on chemokine release were investigated using enzyme-linked immunosorbent assay and on the chemotaxis of THP-1 cells toward platelet releasates. We found that antiplatelet medication acetylsalicylic acid (ASA) led to reduced chemokine (CC motif) ligand 5 (CCL5) and chemokine (CXC motif) ligand 4 (CXCL4) release from platelets, while leukocyte chemotaxis was not affected. Depending on the agonist, α _IIb β ₃ and P2Y ₁₂ inhibitors also affected CCL5 or CXCL4 release. The combination of ASA with a P2Y ₁₂ inhibitor or a phosphodiesterase (PDE) inhibitor did not lead to an additive reduction in CCL5 or CXCL4 release. Interestingly, these combinations did reduce leukocyte chemotaxis. This study provides evidence that combined therapy of ASA and a P2Y ₁₂ or PDE3 inhibitor can decrease the inflammatory leukocyte recruiting potential of the releasate of activated platelets.

Clinical Applications of Aspirin as a Multi-potent Drug Beyond Cardiovascular Implications: A Proof of Concept for Anesthesiologists- A Narrative Review

To the best of our knowledge, aspirin (ASA) is known as a commonly used medication worldwide. Although the cardiovascular aspects of ASA are well-established, recently, it has been identified that ASA can yield multiple extra-cardiovascular therapeutic potencies in facing neurodegenerative disorders, various cancers, inflammatory responses, and the COVID-19 pandemic. In this review, we aimed to highlight the proven role of ASA administration in the variety of non-cardiovascular diseases, particularly in the field of anesthesiology.

Platelet P2Y 12 Receptor Deletion or Pharmacological Inhibition does not Protect Mice from Sepsis or Septic Shock

Introduction  Platelets are increasingly appreciated as key effectors during sepsis, raising the question of the usefulness of antiplatelet drugs to treat patients with sepsis.

Objective  Evaluate the potential contribution of the platelet P2Y ₁₂ receptor in the pathogenesis of polymicrobial-induced sepsis and septic shock in mice.

Methods  The effects of P2Y ₁₂ inhibition using clopidogrel treatment and of platelet-specific deletion of the P2Y ₁₂ receptor in mice were examined in two severity grades of cecal ligation and puncture (CLP) leading to mild sepsis or septic shock.

Results  Twenty hours after induction of the high grade CLP, clopidogrel- and vehicle-treated mice displayed a similar 30% decrease in mean arterial blood pressure (MAP) characteristic of shock. Septic shock-induced thrombocytopenia was not modified by clopidogrel treatment. Plasma concentrations of inflammatory cytokines and myeloperoxidase (MPO) were similarly increased in clopidogrel- and vehicle-treated mice, indicating comparable increase in systemic inflammation. Thrombin-antithrombin (TAT) complexes and the extent of organ damage were also similar. In mild-grade CLP, clopidogrel- and vehicle-treated mice did not display a significant decrease in MAP, while thrombocytopenia and plasma concentrations of TNFα, IL6, IL10, MPO, TAT and organ damage reached similar levels in both groups, although lower than those reached in the high grade CLP. Similarly, mice with platelet-specific deletion of the P2Y ₁₂ receptor were not protected from CLP-induced sepsis or septic shock.

Conclusion  The platelet P2Y ₁₂ receptor does not contribute to the pathogenesis of sepsis or septic shock in mice, suggesting that P2Y ₁₂ receptor antagonists may not be beneficial in patients with sepsis or septic shock.

Complement factor D is linked to platelet activation in human and rodent sepsis

BACKGROUND

The complement factor D (CFD) exerts a regulatory role during infection. However, its physiological function in coagulopathy and its impact on the course of an infection remains unclear.

MATERIALS

Wild-type and CFD-deficient mice (n = 91) were subjected to cecal ligation and puncture to induce sepsis. At several time points, markers of coagulation and the host-immune response were determined. Furthermore, in patients (n = 79) with sepsis or SIRS, CFD levels were related to clinical characteristics, use of antiplatelet drugs and outcome.

RESULTS

Septic CFD-deficient mice displayed higher TAT complexes (p = 0.02), impaired maximal clot firmness, but no relevant platelet drop and reduced GPIIb/IIIa surface expression on platelets (p = 0.03) compared to septic wild-type mice. In humans, higher CFD levels (non-survivors, 5.0 µg/ml to survivors, 3.6 µg/ml; p = 0.015) were associated with organ failure (SOFA score: r = 0.33; p = 0.003) and mortality (75% percentile, 61.1% to 25% percentile, 26.3%). CFD level was lower in patients with antiplatelet drugs (4.5-5.3 µg/ml) than in patients without.

CONCLUSION

In mice, CFD is linked to pronounced platelet activation, depicted by higher GPIIb/IIIa surface expression in wild-type mice. This might be of clinical importance since high CFD plasma concentrations were also associated with increased mortality in sepsis patients.

Acetylsalicylic acid inhibits intravascular coagulation during Staphylococcus aureus-induced sepsis in mice

Antiplatelet therapies have been proposed for the treatment of sepsis, a syndrome resulting from a dysregulated immune response and inappropriate activation of coagulation. Acetylsalicylic acid (ASA) may serve as a potential therapeutic strategy to prevent infection-induced coagulopathy and associated tissue damage. Using intravital microscopy, we found that Staphylococcus aureus infection induced neutrophil recruitment, platelet aggregation, and neutrophil extracellular trap (NET) release in the liver. Mice pretreated with ASA, or animals receiving ASA 3 hours postinfection, had significantly reduced platelet aggregation and NET release. Additionally, ASA-treated mice had reduced intravascular thrombin activity and microvascular occlusion as compared with untreated S aureus-infected mice. This inhibition of coagulation was accompanied by decreased levels of alanine aminotransferase and aspartate aminotransferase in the plasma, indicating less liver damage. Finally, bacterial loads (colony-forming units per milliliter) in liver, lung, and spleen were not different between groups, and the phagocytic capacity of Kupffer cells was preserved following ASA treatment. These results suggest that ASA may serve as a therapeutic approach to sepsis through its ability to reduce the deleterious action of immunothrombi while maintaining innate immune functions.

Circulating MicroRNA Levels Indicate Platelet and Leukocyte Activation in Endotoxemia Despite Platelet P2Y12 Inhibition

There is evidence for the effects of platelet inhibition on innate immune activation. Circulating microRNAs (miRNAs) have been implicated as markers of platelet and leukocyte activation. In the present study, we assessed the effects of P2Y₁₂ inhibitors on platelet and leukocyte miRNAs during endotoxemia. Healthy volunteers were randomly assigned to receive oral ticagrelor (n = 10), clopidogrel (n = 8) or no drug (n = 8) for one week, followed by an intravenous bolus of 2 ng/kg endotoxin. Serum was collected at baseline, after one week of antiplatelet treatment and 6 and 24 h after endotoxin administration. MiRNAs were screened using LNA-based qPCR, followed by TaqMan-qPCR validation of candidates. Clinical validation was performed in 41 sepsis patients. Platelet-enriched miR-197, miR-223 and miR-223* were decreased in volunteers following antiplatelet therapy. Endotoxin increased platelet miRNAs, whilst the opposite effect was seen for leukocyte-enriched miR-150. Neither of these endotoxin-mediated effects were altered by P2Y₁₂ inhibitors. Sepsis patients with fatal outcomes (n = 12) had reduced miR-150 levels compared with survivors (n = 29). In conclusion, we show that miR-150 is downregulated in experimental endotoxemia and can predict survival in sepsis but is unaffected by P2Y₁₂ inhibition. While P2Y₁₂ inhibition reduces platelet-associated miRNAs in healthy volunteers, it fails to attenuate the response of platelet miRNAs to endotoxemia.

Treatment With Acetylsalicylic Acid Reverses Endotoxin Tolerance in Humans In Vivo: A Randomized Placebo-Controlled Study

OBJECTIVE

To investigate immunostimulatory effects of acetylsalicylic acid during experimental human endotoxemia and in sepsis patients.

DESIGN

Double-blind, randomized, placebo-controlled study in healthy volunteers and ex vivo stimulation experiments using monocytes of septic patients.

SETTING

Intensive care research unit of an university hospital.

SUBJECTS

Thirty healthy male volunteers and four sepsis patients.

INTERVENTIONS

Healthy volunteers were challenged IV with endotoxin twice, at a 1-week interval, with each challenge consisting of a bolus of 1 ng/kg followed by continuous administration of 1 ng/kg/hr during 3 hours. Volunteers were randomized to acetylsalicylic acid prophylaxis (80 mg acetylsalicylic acid daily for a 14-d period, starting 7 d before the first endotoxin challenge), acetylsalicylic acid treatment (80 mg acetylsalicylic acid daily for the 7-d period in-between both endotoxin challenges), or the control group (receiving placebo). Furthermore, monocytes of sepsis patients were incubated with acetylsalicylic acid preexposed platelets and were subsequently stimulated with endotoxin.

MEASUREMENTS AND MAIN RESULTS

Acetylsalicylic acid prophylaxis enhanced plasma tumor necrosis factor-α concentrations upon the first endotoxin challenge by 50% compared with the control group (p = 0.02) but did not modulate cytokine responses during the second endotoxin challenge. In contrast, acetylsalicylic acid treatment resulted in enhanced plasma levels of tumor necrosis factor-α (+53%; p = 0.02), interleukin-6 (+91%; p = 0.03), and interleukin-8 (+42%; p = 0.02) upon the second challenge, whereas plasma levels of the key antiinflammatory cytokine interleukin-10 were attenuated (-40%; p = 0.003). This proinflammatory phenotype in the acetylsalicylic acid treatment group was accompanied by a decrease in urinary prostaglandin E metabolite levels (-27% ± 7%; p = 0.01). Ex vivo exposure of platelets to acetylsalicylic acid increased production of tumor necrosis factor-α (+66%) and decreased production of interleukin-10 (-23%) by monocytes of sepsis patients.

CONCLUSIONS

Treatment, but not prophylaxis, with low-dose acetylsalicylic acid, partially reverses endotoxin tolerance in humans in vivo by shifting response toward a proinflammatory phenotype. This acetylsalicylic acid-induced proinflammatory shift was also observed in septic monocytes, signifying that patients suffering from sepsis-induced immunoparalysis might benefit from initiating acetylsalicylic acid treatment.

Inhibition of immunothrombosis does not affect pathogen capture and does not promote bacterial dissemination in a mouse model of sepsis

After infection, neutrophils release neutrophil extracellular traps (NETs), decondensed DNA fibers decorated with both nuclear proteins and proteins derived from intracellular granules. These structures have a fundamental role in the development of immunothrombosis; a physiological process mediated by immune cells and molecules from the coagulation system that facilitates the recognition, containment, and destruction of pathogens. Although NETs and immunothrombi are widely hypothesized to be key host defense responses responsible for limiting bacterial dissemination, their actual role in this process has not been formally assessed within the context of a bloodstream infection. Mice were first treated with LPS to generate inflammation (NETs and immunothrombi) and then bacteria dissemination was analyzed by intravital microscopy and colony-forming units (CFU) assay. Blocking NETs or coagulation by the administration of DNase or Argatroban (thrombin inhibitor), respectively, did not modify the percentage of bacteria capture by Kupffer cells, neutrophils or platelets. Moreover, both inhibitors reduced the number of bacteria in the spleen, without modifying CFUs in the liver or lung. In conclusion, we demonstrate that immunothrombi are not necessary to limit the dissemination of bloodstream bacterial infections.

Platelets in Host Defense: Experimental and Clinical Insights

Platelets are central players in thrombosis and hemostasis but are increasingly recognized as key components of the immune system. They shape ensuing immune responses by recruiting leukocytes, and support the development of adaptive immunity. Recent data shed new light on the complex role of platelets in immunity. Here, we summarize experimental and clinical data on the role of platelets in host defense against bacteria. Platelets bind, contain, and kill bacteria directly; however, platelet proinflammatory effector functions and cross-talk with the coagulation system, can also result in damage to the host (e.g., acute lung injury and sepsis). Novel clinical insights support this dichotomy: platelet inhibition/thrombocytopenia can be either harmful or protective, depending on pathophysiological context. Clinical studies are currently addressing this aspect in greater depth.

Influence of Acetylsalicylic Acid Use on Risk and Outcome of Community-Acquired Staphylococcus aureus Bacteremia: A Population-Based Study

Objective

To investigate the influence of acetylsalicylic acid (ASA) use on risk and outcome of community-acquired Staphylococcus aureus bacteremia (CA-SAB).

Method

We used population-based medical databases to identify all patients diagnosed in northern Denmark with first-time CA-SAB and matched population controls from 2000–2011. Categories for ASA users included current users (new or long-term users), former users, and nonusers. The analyses were adjusted for comorbidities, comedication use, and socioeconomic indicators.

Results

We identified 2638 patients with first-time CA-SAB and 26 379 matched population controls. Compared with nonusers, the adjusted odds ratio (aOR) for CA-SAB was 1.00 (95% confidence interval [CI], 0.88–1.13) for current users, 1.00 (95% CI, 0.86–1.16) for former users, 2.04 (95% CI, 1.42–2.94) for new users, and 0.95 (95% CI, 0.84–1.09) for long-term users. Thirty-day cumulative mortality was 28.0% among current users compared with 21.6% among nonusers, yielding an adjusted hazard rate ratio (aHRR) of 1.02 (95% CI, 0.84–1.25). Compared with nonusers, the aHRR was 1.10 (95% CI, 0.87–1.40) for former users, 0.60 (95% CI, 0.29–1.21) for new users, and 1.06 (95% CI, 0.87–1.31) for long-term users. We observed no difference in the risk or outcome of CA-SAB with increasing ASA dose or by presence of diseases commonly treated with ASA.

Conclusions

Use of ASA did not seem to influence the risk or outcome of CA-SAB. The apparent increased risk among new users may relate to residual confounding from the circumstances underlying ASA treatment initiation. Our finding of no association remained robust with increasing ASA dose and across multiple patient subsets.

Platelets Are Critical Key Players in Sepsis

Host defense against infection is based on two crucial mechanisms: the inflammatory response and the activation of coagulation. Platelets are involved in both hemostasis and immune response. These mechanisms work together in a complex and synchronous manner making the contribution of platelets of major importance in sepsis. This is a summary of the pathophysiology of sepsis-induced thrombocytopenia, microvascular consequences, platelet-endothelial cells and platelet–pathogens interactions. The critical role of platelets during sepsis and the therapeutic implications are also reviewed.

Thromboinflammation: challenges of therapeutically targeting coagulation and other host defense mechanisms

Thrombosis with associated inflammation (thromboinflammation) occurs commonly in a broad range of human disorders. It is well recognized clinically in the context of superficial thrombophlebitis (thrombosis and inflammation of superficial veins); however, it is more dangerous when it develops in the microvasculature of injured tissues and organs. Microvascular thrombosis with associated inflammation is well recognized in the context of sepsis and ischemia-reperfusion injury; however, it also occurs in organ transplant rejection, major trauma, severe burns, the antiphospholipid syndrome, preeclampsia, sickle cell disease, and biomaterial-induced thromboinflammation. Central to thromboinflammation is the loss of the normal antithrombotic and anti-inflammatory functions of endothelial cells, leading to dysregulation of coagulation, complement, platelet activation, and leukocyte recruitment in the microvasculature. α-Thrombin plays a critical role in coordinating thrombotic and inflammatory responses and has long been considered an attractive therapeutic target to reduce thromboinflammatory complications. This review focuses on the role of basic aspects of coagulation and α-thrombin in promoting thromboinflammatory responses and discusses insights gained from clinical trials on the effects of various inhibitors of coagulation on thromboinflammatory disorders. Studies in sepsis patients have been particularly informative because, despite using anticoagulant approaches with different pharmacological profiles, which act at distinct points in the coagulation cascade, bleeding complications continue to undermine clinical benefit. Future advances may require the development of therapeutics with primary anti-inflammatory and cytoprotective properties, which have less impact on hemostasis. This may be possible with the growing recognition that components of blood coagulation and platelets have prothrombotic and proinflammatory functions independent of their hemostatic effects.

Effects of antiplatelet therapy on the mortality rate of patients with sepsis: A meta-analysis

PURPOSE

Abnormal platelet activation plays an important role in the development of sepsis. The effect of antiplatelet drugs on the outcome of patients with sepsis remains unclear. This meta-analysis aimed to determine the effect of antiplatelet drugs on the prognosis of patients with sepsis.

MATERIALS AND METHODS

PubMed, Cochrane Library, CBM, and Embase were searched for all related articles published from inception to April 2018. The primary end point was mortality. Adjusted data were used and statistically analysed.

RESULTS

Ten cohort studies were included. The total number of patients with sepsis was 689,897. Data showed that the use of antiplatelet drugs could effectively reduce the mortality of patients with sepsis (odds ratio (OR) = 0.82, 95% CI: 0.81-0.83, p < 0.05). Seven studies used aspirin for antiplatelet therapy, and subgroup analysis showed that aspirin effectively reduced ICU or hospital mortality in patients with sepsis (OR = 0.60, 95% CI: 0.53-0.68, p < 0.05). A subgroup analysis on the timing of anti-platelet drug administration showed that antiplatelet drugs can reduce mortality when administered either before (OR = 0.78, 95% CI: 0.77-0.80) or after sepsis (OR = 0.59, 95% CI: 0.52-0.67).

CONCLUSIONS

Antiplatelet drugs, particularly aspirin, could be used to effectively reduce mortality in patients with sepsis.

[Antipyretics in intensive care patients]

BACKGROUND

Antipyretics are among the most widely prescribed drugs in German hospitals. Despite this widespread use, their role for treatment of critically ill patients still remains unclear. In particular, the questionable positive effects of reducing fever are discussed.

OBJECTIVES

In this review we aimed to summarize and discuss current study results covering the use of antipyretics in critically ill patients. Suspected effects with regard to fever reduction and lethality should be considered.

MATERIALS AND METHODS

A selective literature search was carried out in the PubMed database. We reviewed the bibliographies of all work considered relevant.

RESULTS

There are only a few studies on the use of antipyretics in intensive care patients, which are difficult to compare systematically due to different designs, protocols and endpoints. All in all, the decrease in temperature was very low (0.3 °C) and showed even adverse effects on 28-days mortality in sepsis. In patients with sepsis and ASS medication, a decreased mortality has been shown in retrospective analysis.

CONCLUSIONS

The benefit of fever control using antipyretics in intensive care patients with regard to endpoints like lethality remains unclear. Randomized controlled trials with suitable protocols and endpoints are needed to provide a solid base for development of guidelines.

The preventive effect of antiplatelet therapy in acute respiratory distress syndrome: a meta-analysis

Background

Acute respiratory distress syndrome (ARDS) is a life-threatening condition with high mortality that imposes a serious medical burden. Antiplatelet therapy is a potential strategy for preventing ARDS in patients with a high risk of developing this condition. A meta-analysis was performed to investigate whether antiplatelet therapy could reduce the incidence of newly developed ARDS and its associated mortality in high-risk patients.

Methods

The Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, Medline, and the Web of Science were searched for published studies from inception to 26 October 2017. We included randomized clinical trials, cohort studies and case-control studies investigating antiplatelet therapy in adult patients presenting to the hospital or ICU with a high risk for ARDS. Baseline patient characteristics, interventions, controls and outcomes were extracted. Our primary outcome was the incidence of newly developed ARDS in high-risk patients. Secondary outcomes were hospital and ICU mortality. A random-effects or fixed-effects model was used for quantitative synthesis.

Results

We identified nine eligible studies including 7660 high-risk patients who received antiplatelet therapy. Based on seven observational studies, antiplatelet therapy was associated with a decreased incidence of ARDS (odds ratio (OR) 0.68, 95% confidence interval (CI) 0.52–0.88; I² = 68.4%, p = 0.004). In two randomized studies, no significant difference was found in newly developed ARDS between the antiplatelet groups and placebo groups (OR 1.32, 95% CI 0.72–2.42; I² = 0.0%, p = 0.329). Antiplatelet therapy did not reduce hospital mortality in randomized studies (OR 1.15, 95% CI 0.58–2.27; I² = 0.0%; p = 0.440) or observational studies (OR 0.80, 95% CI 0.62–1.03; I² = 31.9%, p = 0.221).

Conclusions

Antiplatelet therapy did not significantly decrease hospital mortality in high-risk patients. However, whether antiplatelet therapy is associated with a decreased incidence of ARDS in patients at a high risk of developing the condition remains unclear.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-1988-y) contains supplementary material, which is available to authorized users.

Blood platelets and sepsis pathophysiology: A new therapeutic prospect in critically [corrected] ill patients?

Beyond haemostasis, platelets have emerged as versatile effectors of the immune response. The contribution of platelets in inflammation, tissue integrity and defence against infections has considerably widened the spectrum of their role in health and disease. Here, we propose a narrative review that first describes these new platelet attributes. We then examine their relevance to microcirculatory alterations in multi-organ dysfunction, a major sepsis complication. Rapid progresses that are made on the knowledge of novel platelet functions should improve the understanding of thrombocytopenia, a common condition and a predictor of adverse outcome in sepsis, and may provide potential avenues for management and therapy.

Platelets, inflammation and anti-inflammatory effects of antiplatelet drugs in ACS and CAD

Platelets play a pivotal role in chronic inflammation leading to progression of atherosclerosis and acute coronary events. Recent discoveries on novel mechanisms and platelet-dependent inflammatory targets underpin the role of platelets to maintain a chronic inflammatory condition in cardiovascular disease. There is strong and clinically relevant crosslink between chronic inflammation and platelet activation. Antiplatelet therapy is a cornerstone in the prevention and treatment of acute cardiovascular events. The benefit of antiplatelet agents has mainly been attributed to their direct anti-aggregatory impact. Some anti-inflammatory off-target effects have also been described. However, it is unclear whether these effects are secondary due to inhibition of platelet activation or are caused by direct distinct mechanisms interfering with inflammatory pathways. This article will highlight novel platelet associated targets that contribute to inflammation in cardiovascular disease and elucidate mechanisms by which currently available antiplatelet agents evolve anti-inflammatory capacities, in particular by carving out the differential mechanisms directly or indirectly affecting platelet mediated inflammation. It will further illustrate the prognostic impact of antiplatelet therapies by reducing inflammatory marker release in recent cardiovascular trials.

Quantifying the Effects of Prior Acetyl-Salicylic Acid on Sepsis-Related Deaths: An Individual Patient Data Meta-Analysis Using Propensity Matching

OBJECTIVE

The primary objective was to conduct a meta-analysis on published observational cohort data describing the association between acetyl-salicylic acid (aspirin) use prior to the onset of sepsis and mortality in hospitalized patients.

STUDY SELECTION

Studies that reported mortality in patients on aspirin with sepsis with a comparison group of patients with sepsis not on prior aspirin therapy were included.

DATA SOURCES

Fifteen studies described hospital-based cohorts (n = 17,065), whereas one was a large insurance-based database (n = 683,421). Individual-level patient data were incorporated from all selected studies.

DATA EXTRACTION

Propensity analyses with 1:1 propensity score matching at the study level were performed, using the most consistently available covariates judged to be associated with aspirin. Meta-analyses were performed to estimate the pooled average treatment effect of aspirin on sepsis-related mortality.

DATA SYNTHESIS

Use of aspirin was associated with a 7% (95% CI, 2-12%; p = 0.005) reduction in the risk of death as shown by meta-analysis with considerable statistical heterogeneity (I = 61.6%).

CONCLUSIONS

These results are consistent with effects ranging from a 2% to 12% reduction in mortality risk in patients taking aspirin prior to sepsis onset. This association anticipates results of definitive studies of the use of low-dose aspirin as a strategy for reduction of deaths in patients with sepsis.

The importance of blood platelet lipid signaling in thrombosis and in sepsis

Blood platelets are the first line of defense against hemorrhages and are also strongly involved in the processes of arterial thrombosis, a leading cause of death worldwide. Besides their well-established roles in hemostasis, vascular wall repair and thrombosis, platelets are now recognized as important players in other processes such as inflammation, healing, lymphangiogenesis, neoangiogenesis or cancer. Evidence is accumulating they are key effector cells in immune and inflammatory responses to host infection. To perform their different functions platelets express a wide variety of membrane receptors triggering specific intracellular signaling pathways and largely use lipid signaling systems. Lipid metabolism is highly active in stimulated platelets including the phosphoinositide metabolism with the phospholipase C (PLC) and the phosphoinositide 3-kinase (PI3K) pathways but also other enzymatic systems producing phosphatidic acid, lysophosphatidic acid, platelet activating factor, sphingosine 1-phosphate and a number of eicosanoids. While several of these bioactive lipids regulate intracellular platelet signaling mechanisms others are released by activated platelets acting as autocrine and/or paracrine factors modulating neighboring cells such as endothelial and immune cells. These bioactive lipids have been shown to play important roles in hemostasis and thrombosis but also in vessel integrity and dynamics, inflammation, tissue remodeling and wound healing. In this review, we will discuss some important aspects of platelet lipid signaling in thrombosis and during sepsis that is an important cause of death in intensive care unit. We will particularly focus on the implication of the different isoforms of PI3Ks and on the generation of eicosanoids released by activated platelets.

A randomised trial on the effect of anti-platelet therapy on the systemic inflammatory response in human endotoxaemia

The use of acetylsalicylic acid (ASA) is associated with improved outcome in patients with sepsis, and P2Y₁₂ inhibitors have been suggested to also have immunomodulatory effects. Therefore, we evaluated the effects of clinically relevant combinations of antiplatelet therapy on the immune response in experimental endotoxaemia in humans in vivo. Forty healthy subjects were randomised to seven days of placebo, placebo with ASA, ticagrelor and ASA, or clopidogrel and ASA treatment. Systemic inflammation was elicited at day seven by intravenous administration of Escherichia coli endotoxin. ASA treatment profoundly augmented the plasma concentration of pro-inflammatory cytokines, but did not affect anti-inflammatory cytokines. Addition of either P2Y₁₂ antagonist to ASA did not affect any of the circulating cytokines, except for an attenuation of the ASA-induced increase in TNFα by ticagrelor. Systemic inflammation increased plasma adenosine, without differences between groups, and although P2Y₁₂ inhibition impaired platelet reactivity, there was no correlation with cytokine responses.

Pattern and consequences of cardiologic medications management for patients with elevated troponin I upon admission into an intensive care unit not linked to type 1 acute myocardial infarction: A prospective observational cohort study

OBJECTIVES

No recommendations are currently available to help the clinician with the pharmacological management of intensive care unit (ICU) patients with elevated cardiac troponin (cTn) not linked to type 1 AMI. The aim of this study was to evaluate the pattern of cardiologic medications for patients with elevated cTnI in ICU not link to type 1 AMI and their effects on in-hospital mortality.

MATERIAL AND METHODS

A prospective observational cohort study conducted in two ICU units. Patients with increased plasma concentration of cTnI at admission not linked to type 1 AMI were consecutively included.

RESULTS

One hundred and ninety of the 835 patients admitted (23%) had an increased plasma concentration of cTnI not related to type 1 AMI. Antiplatelet therapy (AT) and statin were prescribed in 56 (29.5%) and 50 (26.3%) of patients, respectively. Others cardiologic medications were prescribed in less than 5% of all cases and were considered as contraindicated in more than 50% of cases. Antiplatelet therapy was the only cardiologic treatment associated with reduction of in-hospital mortality following uni- and multivariate analysis. The death rate was 23% and 40% in these patients treated with and without AT, respectively (aOR=0.39 [95% CI: 0.15-0.97]).

CONCLUSIONS

Statin and AT were frequently prescribed to patients with a cTnI elevation not linked to type 1 AMI. This study suggests that AT in patients with an increased plasma concentration of cTnI, not related to type 1 AMI in ICU, could reduce in-hospital mortality.

Effect of antiplatelet therapy on mortality and acute lung injury in critically ill patients: A systematic review and meta-analysis

Aim:

Platelet function is intricately linked to the pathophysiology of critical Illness, and some studies have shown that antiplatelet therapy (APT) may decrease mortality and incidence of acute respiratory distress syndrome (ARDS) in these patients. Our objective was to understand the efficacy of APT by conducting a meta-analysis.

Materials and Methods:

We conducted a meta-analysis using PubMed, Central, Embase, The Cochrane Central Register, the ClinicalTrials.gov Website, and Google Scholar. Studies were included if they investigated critically ill patients receiving antiplatelet therapy and mentioned the outcomes being studied (mortality, duration of hospitalization, ARDS, and need for mechanical ventilation).

Results:

We found that there was a significant reduction in all-cause mortality in patients on APT compared to control (odds ratio [OR]: 0.83; 95% confidence interval [CI]: 0.70–0.97). Both the incidence of acute lung injury/ARDS (OR: 0.67; 95% CI: 0.57–0.78) and need for mechanical ventilation (OR: 0.74; 95% CI: 0.60–0.91) were lower in the antiplatelet group. No significant difference in duration of hospitalization was observed between the two groups (standardized mean difference: −0.02; 95% CI: −0.11–0.07).

Conclusion:

Our meta-analysis suggests that critically ill patients who are on APT have an improved survival, decreased incidence of ARDS, and decreased need for mechanical ventilation.

AspiriN To Inhibit SEPSIS (ANTISEPSIS) randomised controlled trial protocol

INTRODUCTION

Sepsis is a leading global cause of morbidity and mortality, and is more common at the extremes of age. Moreover, the cost of in-hospital care for elderly patients with sepsis is significant. There are indications from experimental and observational studies that aspirin may reduce inflammation associated with infection. This paper describes the rationale and design of the AspiriN To Inhibit SEPSIS (ANTISEPSIS) trial, a substudy of ASPirin in Reducing Events in the Elderly (ASPREE). ANTISEPSIS primarily aims to determine whether low-dose aspirin reduces sepsis-related deaths in older people. Additionally, it will assess whether low-dose aspirin reduces sepsis-related hospitalisations and sepsis-related Intensive Care Unit (ICU) admissions.

METHODS AND ANALYSIS

ASPREE is a double-blinded, randomised, placebo-controlled primary prevention trial that will determine whether daily low-dose aspirin extends disability-free longevity in 19 000 healthy older people recruited in Australia and the USA. The ANTISEPSIS substudy involves additional ASPREE trial data collection to assess the impact of daily low-dose aspirin on sepsis-related events in the 16 703 ASPREE participants aged 70 years and over, recruited in Australia. The intervention is a daily 100 mg dose of enteric-coated aspirin versus matching placebo, with 1:1 randomisation. The primary outcome for the ANTISEPSIS substudy is the incidence of sepsis-related death in eligible patients. The incidence of sepsis-related hospital and ICU admissions are secondary outcomes. ANTISEPSIS is to be conducted between 2012 and 2018.

DISCUSSION

This substudy will determine whether aspirin, an inexpensive and accessible therapy, safely reduces sepsis-related deaths and hospitalisations in older Australians. If shown to be the case, this would have profound effects on the health of older Australians.

TRIAL REGISTRATION NUMBER

Pre-results, ACTRN12613000349741.

Cardiac Troponin Measurement in the Critically Ill: Potential for Guiding Clinical Management

Elevated cardiac troponin (cTn) in the absence of acute coronary syndromes (ACS) is associated with increased mortality in critically ill patients. There are no evidence-based interventions that reduce mortality in this group.

Human recombinant alkaline phosphatase inhibits ex vivo platelet activation in humans

Sepsis-associated acute kidney injury (AKI) is associated with high morbidity and mortality. Excessive platelet activation contributes to AKI through the formation of microthrombi and amplification of systemic inflammation. Two phase II trials demonstrated that bovine-intestinal alkaline phosphatase (AP) improved renal function in critically ill patients with sepsis-associated AKI. In this study, we characterised the platelet-inhibiting effects of a human recombinant AP. Whole blood and platelet-rich plasma (PRP) of healthy volunteers (n=6) was pre-treated ex vivo with recAP, whereafter platelet reactivity to ADP, collagen-related peptide (CRP-XL) and Pam3CSK4 was determined by flow cytometry. RecAP (40 U/ml) reduced the platelet reactivity to ADP (inhibition with a median of 47 %, interquartile range 43-49 %; p<0.001) and tended to reduce platelet reactivity to CRP-XL (9 %, 2-25 %; p=0.08) in whole blood. The platelet-inhibiting effects of recAP were more pronounced in PRP both for ADP- (64 %, 54-68 %; p=0.002) and CRP-XL-stimulated samples (60 %, 46-71 %; p=0.002). RecAP rapidly converted ADP into adenosine, whereas antagonism of the A2A adenosine receptor partially reversed the platelet inhibitory effects of recAP. Platelets of septic shock patients (n=5) showed a 31% (22-34%; p=0.03) more pronounced reactivity compared to healthy volunteers, and this was completely reversed by recAP treatment. In conclusion, we demonstrate that recAP inhibits ex vivo human platelet activation through dephosphorylation of ADP and formation of adenosine as its turnover product. RecAP is able to reverse the platelet hyperreactivity present in septic shock patients. These effects may contribute to the beneficial effects of recAP as a new therapeutic candidate for sepsis-associated AKI.

Risk factors for mortality in patients admitted to intensive care units with pneumonia

Background

Despite the high mortality in patients with pneumonia admitted to an ICU, data on risk factors for death remain limited.

Methods

In this secondary analysis of PROTECT (Prophylaxis for Thromboembolism in Critical Care Trial), we focused on the patients admitted to ICU with a primary diagnosis of pneumonia. The primary outcome for this study was 90-day hospital mortality and the secondary outcome was 90-day ICU mortality. Cox regression model was conducted to examine the relationship between baseline and time-dependent variables and hospital and ICU mortality.

Results

Six hundred sixty seven patients admitted with pneumonia (43.8 % females) were included in our analysis, with a mean age of 60.7 years and mean APACHE II score of 21.3. During follow-up, 111 patients (16.6 %) died in ICU and in total, 149 (22.3 %) died in hospital. Multivariable analysis demonstrated significant independent risk factors for hospital mortality including male sex (hazard ratio (HR) = 1.5, 95 % confidence interval (CI): 1.1 - 2.2, p-value = 0.021), higher APACHE II score (HR = 1.2, 95 % CI: 1.1 - 1.4, p-value < 0.001 for per-5 point increase), chronic heart failure (HR = 2.9, 95 % CI: 1.6 - 5.4, p-value = 0.001), and dialysis (time-dependent effect: HR = 2.7, 95 % CI: 1.3 - 5.7, p-value = 0.008). Higher APACHE II score (HR = 1.2, 95 % CI: 1.1 - 1.4, p-value = 0.002 for per-5 point increase) and chronic heart failure (HR = 2.6, 95 % CI: 1.3 – 5.0, p-value = 0.004) were significantly related to risk of death in the ICU.

Conclusion

In this study using data from a multicenter thromboprophylaxis trial, we found that male sex, higher APACHE II score on admission, chronic heart failure, and dialysis were independently associated with risk of hospital mortality in patients admitted to ICU with pneumonia. While high illness severity score, presence of a serious comorbidity (heart failure) and need for an advanced life support (dialysis) are not unexpected risk factors of mortality, male sex might necessitate further exploration. More studies are warranted to clarify the effect of these risk factors on survival in critically ill patients admitted to ICU with pneumonia.

Trial registration

ClinicalTrials.gov Identifier: NCT00182143.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0397-5) contains supplementary material, which is available to authorized users.

Effect of Antiplatelet Therapy on Acute Respiratory Distress Syndrome and Mortality in Critically Ill Patients: A Meta-Analysis

BACKGROUND

Antiplatelet agents are commonly used for cardiovascular diseases, but their pleiotropic effects in critically ill patients are controversial. We therefore performed a meta-analysis of cohort studies to investigate the effect of antiplatelet therapy in the critically ill.

METHODS

Nine cohort studies, retrieved from PubMed and Embase before November 2015, involving 14,612 critically ill patients and 4765 cases of antiplatelet users, were meta-analysed. The main outcome was hospital or 30-day mortality. Secondary outcome was acute respiratory distress syndrome (ARDS) or acute lung injury (ALI). Random- or fixed-effect models were taken for quantitative synthesis of the data.

RESULTS

Antiplatelet therapy was associated with decreased mortality (odds ratio (OR) 0.61; 95% confidence interval (CI), 0.52-0.71; I2 = 0%; P <0. 001) and ARDS/ALI (OR 0.64; 95% CI, 0.50-0.82; I2 = 0%; P <0. 001). In every stratum of subgroups, similar findings on mortality reduction were consistently observed in critically ill patients.

CONCLUSIONS

Antiplatelet therapy is associated with reduced mortality and lower incidence of ARDS/ALI in critically ill patients, particularly those with predisposing conditions such as high-risk surgery, trauma, pneumonia, and sepsis. However, it remains unclear whether similar findings can be observed in the unselected and broad population with critical illness.

Iron and a mixture of DHA and EPA supplementation, alone and in combination, affect bioactive lipid signalling and morbidity of iron deficient South African school children in a two-by-two randomised controlled trial

We recently reported that iron supplementation increased respiratory morbidity in iron deficient South African children. This increase, however, was attenuated when iron was provided in combination with a mixture of DHA/EPA. To explore potential underlying mechanisms, we examined the effects of iron and DHA/EPA, alone and in combination, on plasma lipid-derived immune modulator concentrations and related gene expression in peripheral blood mononuclear cells (PBMC). DHA/EPA decreased inflammatory 12-hydroxyeicosatetraenoic acid and tended to increase anti-inflammatory and pro-resolving 17-hydroxydocosahexaenoic acid (17-HDHA), while iron decreased 17-HDHA. However, in combination with iron, the anti-inflammatory effect of DHA/EPA was maintained. These biochemical changes may explain the prevention of iron-induced respiratory morbidity that we observed when iron was supplemented in combination with DHA/EPA during the 8.5 month randomised controlled trial and might lead to a safer approach of delivering iron supplementation. The study was registered at clinicaltrials.gov as NCT01092377.

Chronic antiplatelet therapy is not associated with alterations in the presentation, outcome, or host response biomarkers during sepsis: a propensity-matched analysis

Purpose

Sepsis is a major health burden worldwide. Preclinical investigations in animals and retrospective studies in patients have suggested that inhibition of platelets may improve the outcome of sepsis. In this study we investigated whether chronic antiplatelet therapy impacts on the presentation and outcome of sepsis, and the host response.

Methods

We performed a prospective observational study in 972 patients admitted with sepsis to the mixed intensive care units (ICUs) of two hospitals in the Netherlands between January 2011 and July 2013. Of them, 267 patients (27.5 %) were on antiplatelet therapy (95.9 % acetylsalicylic acid) before admission. To account for differential likelihoods of receiving antiplatelet therapy, a propensity score was constructed, including variables associated with use of antiplatelet therapy. Cox proportional hazards regression was used to estimate the association of antiplatelet therapy with mortality.

Results

Antiplatelet therapy was not associated with sepsis severity at presentation, the primary source of infection, causative pathogens, the development of organ failure or shock during ICU stay, or mortality up to 90 days after admission, in either unmatched or propensity-matched analyses. Antiplatelet therapy did not modify the values of 19 biomarkers providing insight into hallmark host responses to sepsis, including activation of the coagulation system, the vascular endothelium, the cytokine network, and renal function, during the first 4 days after ICU admission.

Conclusions

Pre-existing antiplatelet therapy is not associated with alterations in the presentation or outcome of sepsis, or the host response.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-015-4171-9) contains supplementary material, which is available to authorized users.

Obstructive coronary artery disease in patients hospitalized for severe sepsis or septic shock with concomitant acute myocardial infarction

PURPOSE

It is difficult to differentiate type 1 acute myocardial infarction (AMI) with obstructive coronary artery disease (OCAD) from type 2 AMI in patients admitted for severe sepsis. The aims of this study were to assess the risk factors and prognosis of OCAD in patients admitted to the intensive care unit for severe sepsis with concomitant AMI.

MATERIALS AND METHODS

This is a single-center retrospective cohort study including all consecutive patients who were hospitalized for severe sepsis or septic shock between March 2006 and September 2014 and who underwent coronary angiography in the intensive care unit to identify AMI.

RESULTS

Overall, 78 (5.5%) of 1418 patients hospitalized for severe sepsis underwent coronary angiography to identify concomitant AMI. Thirty-two patients (41%) had OCAD. Following multivariate analysis, the risk factors of OCAD were peripheral vascular disease (odds ratio [OR] =5.7; 95% confidence interval [CI], 1.1-30.4; P = .042) and at least 2 cardiovascular risk factors (OR = 6.7; 95% CI, 1.9-23.8; P = .003). Obstructive coronary artery disease was associated with a significant mortality increase at 60 days (OR = 8.1; 95% CI, 1.9-30.2; P = .004).

CONCLUSIONS

Obstructive coronary artery disease is a poor prognosis factor in patients hospitalized for severe sepsis with concomitant AMI. In this setting, medical treatment should be considered for patients with peripheral vascular disease or with at least 2 cardiovascular risk factors; the need to perform coronary angiography should be considered carefully.

Group G streptococci mediate fibrinogen-dependent platelet aggregation leading to transient entrapment in platelet aggregates

Platelets have been reported to become activated in response to bacteria and this is proposed to contribute to the acute response to bacterial infection. In the present study, we investigated platelet aggregation in response to group G streptococci (GGS) in vitro in healthy human donors and in vivo in a mouse model of streptococcal sepsis. Platelet aggregation by GGS was dependent on the bacterial surface protein FOG and engagement of the platelet fibrinogen receptor; however, it was independent of IgG and the platelet Fc receptor. Platelets exerted no antibacterial effects on the bacteria, and aggregates formed were markedly unstable, allowing bacteria to rapidly return to the plasma and grow post-aggregation. Thrombocytopenia and platelet activation occurred during invasive infection with GGS, and platelets were demonstrated to contribute to bacterial dissemination during infection. These findings reveal an important role for bacteria-platelet interactions during the pathogenesis of streptococcal infection.

Aspirin as a potential treatment in sepsis or acute respiratory distress syndrome

Sepsis is a common condition that is associated with significant morbidity, mortality and health-care cost. Pulmonary and non-pulmonary sepsis are common causes of the acute respiratory distress syndrome (ARDS). The mortality from ARDS remains high despite protective lung ventilation, and currently there are no specific pharmacotherapies to treat sepsis or ARDS. Sepsis and ARDS are characterised by activation of the inflammatory cascade. Although there is much focus on the study of the dysregulated inflammation and its suppression, the associated activation of the haemostatic system has been largely ignored until recently. There has been extensive interest in the role that platelet activation can have in the inflammatory response through induction, aggregation and activation of leucocytes and other platelets. Aspirin can modulate multiple pathogenic mechanisms implicated in the development of multiple organ dysfunction in sepsis and ARDS. This review will discuss the role of the platelet, the mechanisms of action of aspirin in sepsis and ARDS, and aspirin as a potential therapy in treating sepsis and ARDS.

Proteomic analysis of differential protein expression in platelets of septic patients

Sepsis is one of the major health problems all over the world. Early diagnostic of sepsis is an attractive strategy to decrease the mortality of septic patients. However, an effective biomarker that fulfills all the necessary requirements for the accurate characterization of sepsis is still unavailable until now. In this study, the 2-DE technique followed by mass spectrometry and a database search was used for searching and identifying the differential expressed proteins in platelets between septic patients and paired healthy controls. Platelet 2-DE profiles of septic patients and paired healthy controls with high resolution and reproducibility were obtained. Differential platelet 2-DE profiles between septic patients and paired healthy controls were established. Differential protein spots between normal healthy volunteers and septic patients from platelet 2-DE profiles were identified by 2-DE followed with mass spectrometry and a database search. Five proteins with increased expression were identified between septic patients and healthy controls from platelet samples. These up-expressed proteins were EF-hand calcium-binding domain-containing protein 7, actin, interleukin-1β, glycoprotein IX, and glycoprotein IIB. Sepsis induces a complex regulation of platelet protein changes. Our study highlights the important role of these differential expressed proteins in sepsis, which deserve further research as potential candidates for therapeutic strategies. Furthermore, our research is beneficial for the future developments of sepsis diagnosis and therapy.

Lipid mediators in immune dysfunction after severe inflammation

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Aberrant LM levels contribute to immune dysfunction in CI.

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Aberrance reflects dysregulation of inflammatory resolution pathways or their failure.

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Targeted manipulation of LMs restores immune competence and outcomes in animal models.

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Stratified resolution-based immunomodulatory strategies hold therapeutic potential.

Sepsis, trauma, burns, and major surgical procedures activate common systemic inflammatory pathways. Nosocomial infection, organ failure, and mortality in this patient population are associated with a quantitatively different reprioritization of the circulating leukocyte transcriptome to the initial inflammatory insult, greater in both magnitude and duration, and secondary to multiple observed defects in innate and adaptive immune function. Dysregulation of inflammatory resolution processes and associated bioactive lipid mediators (LMs) mechanistically contribute to this phenotype. Recent data indicate the potential efficacy of therapeutic interventions that either reduce immunosuppressive prostaglandins (PGs) or increase specialized proresolving LMs. Here, we reassess the potential for pharmacological manipulation of these LMs as therapeutic approaches for the treatment of critical illness (CI).