Previous immune checkpoint inhibitor therapy is associated with decreased COVID-19-related hospitalizations and complications in patients with cancer: Results of a propensity-matched analysis of the OnCovid registry.

OBJECTIVES: To date, studies have not provided definitive answers regarding whether previous immune checkpoint inhibitor (ICI) treatment alters outcomes for cancer patients with COVID-19. METHODS: The OnCovid registry (NCT04393974) was searched from February 27, 2020, to January 31, 2022, for patients who received systemic anti-cancer therapy in the 4 weeks before laboratory-confirmed COVID-19 diagnosis. Propensity-score matching using country, vaccination status, primary tumor type, sex, age, comorbidity burden, tumor stage, and remission status investigated differences in predefined clinical outcomes comparing those who had or had not received ICIs. RESULTS: Of 3523 patients screened, 137 ICI-only and 1378 non-ICI met inclusion criteria. Before matching, ICI patients were older, male, enrolled at centers in Italy, and had histories of smoking, thoracic cancers, advanced cancer stages, and active malignancies (P ≤0.02). After matching, there were 120 ICI and 322 non-ICI patients. ICI patients had no differences (odds ratio: 95% CI) in presenting COVID-19 symptoms (0.69: 0.37-1.28), receipt of COVID-specific therapy (0.88: 0.54-1.41), 14-day (0.95: 0.56-1.61), or 28-day (0.79: 0.48-1.29) mortalities. However, ICI patients required less COVID-19-related hospitalization (0.37: 0.21-0.67) and oxygen therapy (0.51: 0.31-0.83) and developed fewer complications (0.57: 0.36-0.92). CONCLUSION: In this propensity-score matched analysis, previous ICI therapy did not worsen and potentially improved COVID-19 outcomes in patients with cancer.

Anti-PD-L1 therapy altered inflammation but not survival in a lethal murine hepatitis virus-1 pneumonia model.

Introduction: Because prior immune checkpoint inhibitor (ICI) therapy in cancer patients presenting with COVID-19 may affect outcomes, we investigated the beta-coronavirus, murine hepatitis virus (MHV)-1, in a lethal pneumonia model in the absence (Study 1) or presence of prior programmed cell death ligand-1 (PD-L1) antibody (PD-L1mAb) treatment (Study 2). Methods: In Study 1, animals were inoculated intratracheally with MHV-1 or vehicle and evaluated at day 2, 5, and 10 after infection. In Study 2, uninfected or MHV-1-infected animals were pretreated intraperitoneally with control or PD-L1-blocking antibodies (PD-L1mAb) and evaluated at day 2 and 5 after infection. Each study examined survival, physiologic and histologic parameters, viral titers, lung immunophenotypes, and mediator production. Results: Study 1 results recapitulated the pathogenesis of COVID-19 and revealed increased cell surface expression of checkpoint molecules (PD-L1, PD-1), higher expression of the immune activation marker angiotensin converting enzyme (ACE), but reduced detection of the MHV-1 receptor CD66a on immune cells in the lung, liver, and spleen. In addition to reduced detection of PD-L1 on all immune cells assayed, PD-L1 blockade was associated with increased cell surface expression of PD-1 and ACE, decreased cell surface detection of CD66a, and improved oxygen saturation despite reduced blood glucose levels and increased signs of tissue hypoxia. In the lung, PD-L1mAb promoted S100A9 but inhibited ACE2 production concomitantly with pAKT activation and reduced FOXO1 levels. PD-L1mAb promoted interferon-γ but inhibited IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF) production, contributing to reduced bronchoalveolar lavage levels of eosinophils and neutrophils. In the liver, PD-L1mAb increased viral clearance in association with increased macrophage and lymphocyte recruitment and liver injury. PD-L1mAb increased the production of virally induced mediators of injury, angiogenesis, and neuronal activity that may play role in COVID-19 and ICI-related neurotoxicity. PD-L1mAb did not affect survival in this murine model. Discussion: In Study 1 and Study 2, ACE was upregulated and CD66a and ACE2 were downregulated by either MHV-1 or PD-L1mAb. CD66a is not only the MHV-1 receptor but also an identified immune checkpoint and a negative regulator of ACE. Crosstalk between CD66a and PD-L1 or ACE/ACE2 may provide insight into ICI therapies. These networks may also play role in the increased production of S100A9 and neurological mediators in response to MHV-1 and/or PD-L1mAb, which warrant further study. Overall, these findings support observational data suggesting that prior ICI treatment does not alter survival in patients presenting with COVID-19.

Comprehensive adjusted outcome data are needed to assess the impact of immune checkpoint inhibitors in cancer patients with COVID-19: Results of a systematic review and meta-analysis.

BACKGROUND: Determining how prior immune checkpoint inhibitor (ICI) therapy influences outcomes in cancer patients presenting with COVID-19 is essential for patient management but must account for confounding variables. METHODS: We performed a systematic review and meta-analysis of studies reporting adjusted effects of ICIs on survival, severe events, or hospitalisation in cancer patients with COVID-19 based on variables including age, gender, diabetes mellitus, hypertension (HTN), chronic obstructive pulmonary disease, and other comorbidities. When adjusted effects were unavailable, unadjusted data were analysed. RESULTS: Of 42 observational studies (38 retrospective), 7 reported adjusted outcomes for ICIs and 2 provided sufficient individual patient data to calculate adjusted outcomes. In eight studies, adjusted outcomes were based on ≤7 variables. Over all studies, only one included >100 ICI patients while 26 included <10. ICIs did not alter the odds ratio (95%CI) (OR) of death significantly (random effects model), across adjusted (n = 8) [1.31 (0.58-2.95) p = 0.46; I2  = 42%, p = 0.10], unadjusted (n = 30) [1.06 (0.85-1.32) p = 0.58; I2  = 0%, p = 0.76] or combined [1.09 (0.88;1.36) p = 0.41; I2  = 0%, p = 0.5)] studies. Similarly, ICIs did not alter severe events significantly across adjusted (n = 5) [1.20 (0.30-4.74) p = 0.73; I2  = 52%, p = 0.08], unadjusted (n = 19) [(1.23 (0.87-1.75) p = 0.23; I2  = 16%, p = 0.26] or combined [1.26 (0.90-1.77) p = 0.16; I2  = 25%, p = 0.14] studies. Two studies provided adjusted hospitalisation data and when combined with 13 unadjusted studies, ICIs did not alter hospitalisation significantly [1.19 (0.85-1.68) p = 029; I2  = 5%, p = 0.40]. Results of sensitivity analyses examining ICI effects based on 5 variables were inconclusive. Certainty of evidence was very low. CONCLUSIONS: Across studies with adjusted and unadjusted results, ICIs did not alter outcomes significantly. But studies with comprehensive adjusted outcome data controlling for confounding variables are necessary to determine whether ICIs impact COVID-19 outcomes in cancer patients.

Effects of chloroquine or hydroxychloroquine treatment on non-SARS-CoV2 viral infections: A systematic review of clinical studies.

Chloroquine (CQ) and hydroxychloroquine (HCQ) have been used as antiviral agents for the treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection. We performed a systematic review to examine whether prior clinical studies that compared the effects of CQ and HCQ to a control for the treatment of non-SARS-CoV2 infection supported the use of these agents in the present SARS-CoV2 outbreak. PubMed, EMBASE, Scopus and Web of Science (PROSPERO CRD42020183429) were searched from inception through 2 April 2020 without language restrictions. Of 1766 retrieved reports, 18 studies met our inclusion criteria, including 17 prospective controlled studies and one retrospective study. CQ or HCQ were compared to control for the treatment of infectious mononucleosis (EBV, n = 4), warts (human papillomavirus, n = 2), chronic HIV infection (n = 6), acute chikungunya infection (n = 1), acute dengue virus infection (n = 2), chronic HCV (n = 2), and as preventive measures for influenza infection (n = 1). Survival was not evaluated in any study. For HIV, the virus that was most investigated, while two early studies suggested HCQ reduced viral levels, four subsequent ones did not, and in two of these CQ or HCQ increased viral levels and reduced CD4 counts. Overall, three studies concluded CQ or HCQ were effective; four concluded further research was needed to assess the treatments' effectiveness; and 11 concluded that treatment was ineffective or potentially harmful. Prior controlled clinical trials with CQ and HCQ for non-SARS-CoV2 viral infections do not support these agents' use for the SARS-CoV2 outbreak.

Bacillus anthracis edema toxin inhibits hypoxic pulmonary vasoconstriction via edema factor and cAMP-mediated mechanisms in isolated perfused rat lungs.

Bacillus anthracis edema toxin (ET) inhibited lethal toxin-stimulated pulmonary artery pressure (Ppa) and increased lung cAMP levels in our previous study. We therefore examined whether ET inhibits hypoxic pulmonary vasoconstriction (HPV). Following baseline hypoxic measures in isolated perfused lungs from healthy rats, compared with diluent, ET perfusion reduced maximal Ppa increases (mean ± SE percentage of maximal Ppa increase with baseline hypoxia) during 6-min hypoxic periods (FIO2 = 0%) at 120 min (16 ± 6% vs. 51 ± 6%, P = 0.004) and 180 min (11.4% vs. 55 ± 6%, P = 0.01). Protective antigen-mAb (PA-mAb) and adefovir inhibit host cell edema factor uptake and cAMP production, respectively. In lungs perfused with ET following baseline measures, compared with placebo, PA-mAb treatment increased Ppa during hypoxia at 120 and 180 min (56 ± 6% vs. 10 ± 4% and 72 ± 12% vs. 12 ± 3%, respectively, P ≤ 0.01) as did adefovir (84 ± 10% vs. 16.8% and 123 ± 21% vs. 26 ± 11%, respectively, P ≤ 0.01). Compared with diluent, lung perfusion with ET for 180 min reduced the slope of the relationships between Ppa and increasing concentrations of endothelin-1 (ET-1) (21.12 ± 2.96 vs. 3.00 ± 0.76 × 108 cmH2O/M, P < 0.0001) and U46619, a thromboxane A2 analogue (7.15 ± 1.01 vs. 3.74 ± 0.31 × 107 cmH2O/M, P = 0.05) added to perfusate. In lungs isolated from rats after 15 h of in vivo infusions with either diluent, ET alone, or ET with PA-mAb, compared with diluent, the maximal Ppa during hypoxia and the slope of the relationship between change in Ppa and ET-1 concentration added to the perfusate were reduced in lungs from animals challenged with ET alone (P ≤ 0.004) but not with ET and PA-mAb together (P ≥ 0.73). Inhibition of HPV by ET could aggravate hypoxia during anthrax pulmonary infection.NEW & NOTEWORTHY The most important findings here are edema toxin's potent adenyl cyclase activity can interfere with hypoxic pulmonary vasoconstriction, an action that could worsen hypoxemia during invasive anthrax infection with lung involvement. These findings, coupled with other studies showing that lethal toxin can disrupt pulmonary vascular integrity, indicate that both toxins can contribute to pulmonary pathophysiology during infection. In combination, these investigations provide a further basis for the use of antitoxin therapies in patients with worsening invasive anthrax disease.

Bacillus anthracis lethal toxin, but not edema toxin, increases pulmonary artery pressure and permeability in isolated perfused rat lungs.

Although lethal toxin (LT) and edema toxin (ET) contribute to lethality during Bacillus anthracis infection, whether they increase vascular permeability and the extravascular fluid accumulation characterizing this infection is unclear. We employed an isolated perfused Sprague-Dawley rat lung model to investigate LT and ET effects on pulmonary vascular permeability. Lungs (n ≥ 6 per experimental group) were isolated, ventilated, suspended from a force transducer, and perfused. Lung weight and pulmonary artery (Ppa) and left atrial pressures were measured over 4 h, after which pulmonary capillary filtration coefficients (Kf.c) and lung wet-to-dry weight ratios (W/D) were determined. When compared with controls, LT increased Ppa over 4 h and Kf.c and W/D at 4 h (P < 0.0001). ET decreased Ppa in a significant trend (P = 0.09) but did not significantly alter Kf.c or W/D (P ≥ 0.29). Edema toxin actually blocked LT increases in Ppa but not LT increases in Kf.c and W/D. When Ppa was maintained at control levels, LT still increased Kf.c and W/D (P ≤ 0.004). Increasing the dose of each toxin five times significantly increased and a toxin-directed monoclonal antibody decreased the effects of each toxin (P ≤ 0.05). Two rho-kinase inhibitors (GSK269962 and Y27632) decreased LT increases in Ppa (P ≤ 0.02) but actually increased Kf.c and W/D in LT and control lungs (P ≤ 0.05). A vascular endothelial growth factor receptor inhibitor (ZM323881) had no significant effect (P ≥ 0.63) with LT. Thus, LT but not ET can increase pulmonary vascular permeability independent of increased Ppa and could contribute to pulmonary fluid accumulation during anthrax infection. However, pulmonary vascular dilation with ET could disrupt protective hypoxic vasoconstriction. NEW & NOTEWORTHY The most important findings from the present study are that Bacillus anthracis lethal toxin increases pulmonary artery pressure and pulmonary permeability independently in the isolated rat lung, whereas edema toxin decreases the former and does not increase permeability. Each effect could be a basis for organ dysfunction in patients with this lethal infection. These findings further support the need for adjunctive therapies that limit the effects of both toxins during infection.

Bacillus anthracis Edema Toxin Increases Fractional Free Water and Sodium Reabsorption in an Isolated Perfused Rat Kidney Model.

Bacillus anthracis edema toxin (ET) consists of protective antigen (PA), necessary for host cell toxin uptake, and edema factor (EF), the toxic moiety which increases host cell cyclic AMP (cAMP). Since vasopressin stimulates renal water and sodium reabsorption via increased tubular cell cAMP levels, we hypothesized the ET would also do so. To test this hypothesis, we employed an isolated perfused rat kidney model. Kidneys were isolated and perfused with modified Krebs-Henseleit buffer. Perfusate and urine samples were obtained at baseline and every 10 min over 150 min following the addition of challenges with or without treatments to the perfusate. In kidneys perfused under constant flow or constant pressure, compared to PA challenge (n = 14 or 15 kidneys, respectively), ET (13 or 15 kidneys, respectively) progressively increased urine cAMP levels, water and sodium reabsorption, and urine osmolality and decreased urine output (P ≤ 0.04, except for sodium reabsorption under constant pressure [P = 0.17]). In ET-challenged kidneys, compared to placebo treatment, adefovir, an EF inhibitor, decreased urine cAMP levels, water and sodium reabsorption, and urine osmolality and increased urine output, while raxibacumab, a PA-directed monoclonal antibody (MAb), decreased urine cAMP levels, free water reabsorption, and urine osmolality and increased urine output (P ≤ 0.03 except for urine output with raxibacumab [P = 0.17]). Upon immunohistochemistry, aquaporin 2 was concentrated along the apical membrane of tubular cells with ET but not PA, and urine aquaporin 2 levels were higher with ET (5.52 ± 1.06 ng/ml versus 1.51 ± 0.44 ng/ml [means ± standard errors of the means {SEM}; P = 0.0001). Edema toxin has renal effects that could contribute to extravascular fluid collection characterizing anthrax infection clinically.

Analysis of Anthrax Immune Globulin Intravenous with Antimicrobial Treatment in Injection Drug Users, Scotland, 2009-2010.

We studied anthrax immune globulin intravenous (AIG-IV) use from a 2009-2010 outbreak of Bacillus anthracis soft tissue infection in injection drug users in Scotland, UK, and we compared findings from 15 AIG-IV recipients with findings from 28 nonrecipients. Death rates did not differ significantly between recipients and nonrecipients (33% vs. 21%). However, whereas only 8 (27%) of 30 patients at low risk for death (admission sequential organ failure assessment score of 0-5) received AIG-IV, 7 (54%) of the 13 patients at high risk for death (sequential organ failure assessment score of 6-11) received treatment. AIG-IV recipients had surgery more often and, among survivors, had longer hospital stays than did nonrecipients. AIG-IV recipients were sicker than nonrecipients. This difference and the small number of higher risk patients confound assessment of AIG-IV effectiveness in this outbreak.

Confirmed Bacillus anthracis infection among persons who inject drugs, Scotland, 2009-2010.

In Scotland, the 2009 outbreak of Bacillus anthracis infection among persons who inject drugs resulted in a 28% death rate. To compare nonsurvivors and survivors, we obtained data on 11 nonsurvivors and 16 survivors. Time from B. anthracis exposure to symptoms or hospitalization and skin and limb findings at presentation did not differ between nonsurvivors and survivors. Proportionately more nonsurvivors had histories of excessive alcohol use (p = 0.05) and required vasopressors and/or mechanical ventilation (p≤0.01 for each individually). Nonsurvivors also had higher sequential organ failure assessment scores (mean ± SEM) (7.3 ± 0.9 vs. 1.2 ± 0.4, p<0.0001). Antibacterial drug administration, surgery, and anthrax polyclonal immune globulin treatments did not differ between nonsurvivors and survivors. Of the 14 patients who required vasopressors during hospitalization, 11 died. Sequential organ failure assessment score or vasopressor requirement during hospitalization might identify patients with injectional anthrax for whom limited adjunctive therapies might be beneficial.

Purified cell wall from the probiotic bacterium Lactobacillus gasseri activates systemic inflammation and, at higher doses, produces lethality in a rat model.

INTRODUCTION: One proposed benefit of probiotic therapy is that probiotic bacterial cell-wall binding to intestinal cell pathogen-recognition receptors activates protective innate immunity. However, in critically ill patients, intestinal epithelium disruption by shock or other insults may compromise this compartmentalized response and cause systemic bacteria and cell-wall translocation. The effects of intravascular introduction of probiotic bacterial cell wall are unclear. METHODS: We investigated 24-hour infusions of purified cell wall from Lactobacillus gasseri ATC33323 (L. gasseri), a probiotic bacterium, in Sprague-Dawley rats (n = 49). RESULTS: Increasing cell-wall doses (0 (control), 10, 20, 40, 80, or 160 mg/kg over 24 hours) produced dose-ordered decreases in survival measured after 168 hours (11 survivors/11 total (100%), seven of seven (100%), seven of seven (100%), six of eight (75%), five of eight (63%), and one of nine (11%), respectively, P < 0.0001). The L. gasseri cell wall was equally or more lethal than Staphylococcus aureus cell wall, which was previously studied (100% to 88% survival with the same increasing doses). During challenge, compared with controls, L. gasseri cell wall produced increases in blood IL-1ß, IL-10, tumor necrosis factor-α, migratory inhibitory protein-1α, monocyte chemotactic protein-1, and nitric oxide, and decreases in neutrophils, lymphocytes, and platelets that were greater with higher versus lower doses (P ≤ 0.05). Medium-dose cell wall (40 and 80 mg/kg combined) progressively decreased blood pressure and increased heart rate, and all doses increased lactate, hepatic transaminases, and creatinine phosphokinase (P ≤ 0.05). CONCLUSION: Although L. gasseri, like other probiotic bacteria, is considered safe, its cell wall can stimulate the maladaptive inflammatory response associated with pathogenic bacteria. Such effects deserve study, especially regarding critically ill patients.

Antitumor necrosis factor therapy is associated with improved survival in clinical sepsis trials: a meta-analysis.

OBJECTIVES: Sepsis is a lethal syndrome annually affecting approximately 900,000 patients in the United States alone. Despite their benefit in rheumatoid disease, selective antitumor necrosis factor agents failed to improve outcome in early sepsis trials in the 1990s. However, data from additional sepsis trials testing these agents are now available. We therefore sought to determine the effect on survival of selective antitumor necrosis factor agents in randomized clinical sepsis trials.. DATA SOURCES: PubMed, Scopus, Embase, and Web of Science. STUDY SELECTION: Randomized human sepsis trials of selective antitumor necrosis factor agents reporting survival rates. DATA EXTRACTION: Two investigators independently collected relevant data on study characteristics, treatment interventions, and patients from each study. DATA SYNTHESIS: Antitumor necrosis factor agents in 15 sepsis trials (n=8,896 patients) meeting inclusion criteria had similar effects (I=0, p=0.84) and compared with controls (placebo in 14 trials or a lower dose in one trial) overall decreased the relative risk of death (95% CI) (0.93 [0.88-0.98], p=0.01). In subgroup analysis, tumor necrosis factor monoclonal antibodies (10 trials, n=6,818) alone produced a significant survival benefit (0.93 [0.87, 0.99], p=0.02) (I=0, p=0.83). Tumor necrosis factor polyclonal antibodies (two trials, n=151) and low-molecular-weight soluble receptor (two trials, n=1,786) had similar beneficial effects to antitumor necrosis factor agents overall (0.82 [0.49-1.37], p=0.45; 0.93 [0.81-1.08], p=0.33, respectively). The effect of tumor necrosis factor high-molecular-weight soluble receptor (one trial, n=141) was not significantly different from other agents but was on the side of harm (1.50 [0.86-2.61], p=0.16). CONCLUSION: Antitumor necrosis factor agents produced a modest but significant decrease in the risk of dying with sepsis. Prior individual trials failed to demonstrate benefit, likely because they were underpowered. A definitive trial demonstrating the potential benefit of such agents might require 10,000 or more patients with sepsis.

B. anthracis edema toxin increases cAMP levels and inhibits phenylephrine-stimulated contraction in a rat aortic ring model.

B. anthracis edema toxin (ET) and lethal toxin (LT) are each composed of protective antigen (PA), necessary for toxin uptake by host cells, and their respective toxic moieties, edema factor (EF) and lethal factor (LF). Although both toxins likely contribute to shock during infection, their mechanisms are unclear. To test whether ET and LT produce arterial relaxation, their effects on phenylephrine (PE)-stimulated contraction in a Sprague-Dawley rat aortic ring model were measured. Rings were prepared and connected to pressure transducers. Their viability was confirmed, and peak contraction with 60 mM KCl was determined. Compared with PA pretreatment (control, 60 min), ET pretreatment at concentrations similar to those noted in vivo decreased the mean (±SE) maximum contractile force (MCF; percent peak contraction) in rings generated during stimulation with increasing PE concentrations (96.2 ± 7.0 vs. 57.3 ± 9.1) and increased the estimated PE concentration producing half the MCF (EC50; 10(-7) M, 1.1 ± 0.3 vs. 3.7 ± 0.8, P ≤ 0.002). ET inhibition with PA-directed monoclonal antibodies, selective EF inhibition with adefovir, or removal of the ring endothelium inhibited the effects of ET on MCF and EC50 (P ≤ 0.02). Consistent with its adenyl cyclase activity, ET increased tissue cAMP in endothelium-intact but not endothelium-denuded rings (P < 0.0001 and 0.25, respectively). LT pretreatment, even in high concentrations, did not significantly decrease MCF or increase EC50 (all P > 0.05). In rings precontracted with PE compared with posttreatment with PA (90 min), ET posttreatment produced progressive reductions in contractile force and increases in relaxation in endothelium-intact rings (P < 0.0001) but not endothelium-denuded rings (P = 0.51). Thus, ET may contribute to shock by producing arterial relaxation.

Efficacy of selective mineralocorticoid and glucocorticoid agonists in canine septic shock.

OBJECTIVE: Corticosteroid regimens that stimulate both mineralocorticoid and glucocorticoid pathways consistently reverse vasopressor-dependent hypotension in septic shock but have variable effects on survival. The objective of this study was to determine whether exogenous mineralocorticoid and glucocorticoid treatments have distinct effects and whether the timing of administration alters their effects in septic shock. DESIGN, SETTING, SUBJECTS, AND INTERVENTIONS: Desoxycorticosterone, a selective mineralocorticoid agonist; dexamethasone, a selective glucocorticoid agonist; and placebo were administered either several days before (prophylactic) or immediately after (therapeutic) infectious challenge and continued for 96 hrs in 74 canines with staphylococcal pneumonia. MEASUREMENTS AND MAIN RESULTS: Effects of desoxycorticosterone and dexamethasone were different and opposite depending on timing of administration for survival (p = .05); fluid requirements (p = .05); central venous pressures (p ≤ .007); indicators of hemoconcentration (i.e., sodium [p = .0004], albumin [p = .05], and platelet counts [p = .02]); interleukin-6 levels (p = .04); and cardiac dysfunction (p = .05). Prophylactic desoxycorticosterone treatment significantly improved survival, shock, and all the other outcomes stated, but therapeutic desoxycorticosterone did not. Conversely, prophylactic dexamethasone was much less effective for improving these outcomes compared with therapeutic dexamethasone with the exception of shock reversal. Prophylactic dexamethasone given before sepsis induction also significantly reduced serum aldosterone and cortisol levels and increased body temperature and lactate levels compared with therapeutic dexamethasone (p ≤ .05), consistent with adrenal suppression. CONCLUSIONS: In septic shock, mineralocorticoids are only beneficial if given prophylactically, whereas glucocorticoids are most beneficial when given close to the onset of infection. Prophylactic mineralocorticoids should be further investigated in patients at high risk to develop sepsis, whereas glucocorticoids should only be administered therapeutically to prevent adrenal suppression and worse outcomes.

The evolving experience with therapeutic TNF inhibition in sepsis: considering the potential influence of risk of death.

INTRODUCTION: Septic shock is highly lethal and its incidence is increasing. Although TNF-α plays a key role in sepsis pathogenesis, past efforts to therapeutically inhibit it had limited success. However, there is continued interest in such therapies and there are now ongoing Phase II sepsis trials testing the effects of AZD9773, a TNF-directed polyclonal antibody fragment preparation. Experience with anti-inflammatory agents suggested that their efficacy may relate to sepsis-associated risk of death. AREAS COVERED: An overview of the biology of TNF and experimental data implicating TNF as a key mediator in sepsis pathogenesis; a review of the earlier clinical experience with anti-TNF therapies demonstrating that when examined across 12 trials, these agents had a highly consistent overall effect which although not reaching significance, was on the side of benefit; a review of data showing that sepsis-associated risk of death may influence the efficacy of anti-inflammatory agents like anti-TNF ones and a review of the rational and clinical experience to date with AZD9773 and its precursor, CytoFab. EXPERT OPINION: Discusses variables that may need to be accounted for to maximize the success of clinical trials in sepsis testing agents that modulate host inflammation.

The individual survival benefits of tumor necrosis factor soluble receptor and fluid administration are not additive in a rat sepsis model.

BACKGROUND: Tumor necrosis factor (TNF) antagonists [e.g., TNF soluble receptor (TNFsr)] improved survival in preclinical but not clinical sepsis trials. However fluid support-itself beneficial-is standard clinically but rarely employed in preclinical sepsis models. We hypothesized that these therapies may not have additive benefit. METHODS AND RESULTS: Antibiotic-treated rats (n = 156) were randomized to intratracheal or intravenous Escherichia coli challenges (>LD50) and either placebo or TNFsr and 24 h fluid treatments alone or together. The survival effects of these therapies did not differ significantly comparing challenge routes. When averaged across route, while TNFsr or fluid alone decreased the hazard ratio of death significantly [ln ± standard error (SE): -0.65 ± 0.30 and -0.62 ± 0.30, respectively, p ≤ 0.05], together they did not (p = 0.16). Furthermore, the observed effect of TNFsr and fluid together on reducing the hazard ratio was significantly less than estimated (-0.37 ± 0.29 versus -1.27 ± 0.43, respectively, p = 0.027) based on TNFsr and fluid alone. While each treatment increased central venous pressure at 6 and 24 h, the observed effects of the combination were also less than estimated ones (p ≤ 0.0005). CONCLUSIONS: The individual survival benefits of TNFsr and fluids were not additive in this rat sepsis model. Investigating new sepsis therapies together with conventional ones during preclinical testing may be informative.

Anthrax edema toxin has cAMP-mediated stimulatory effects and high-dose lethal toxin has depressant effects in an isolated perfused rat heart model.

While anthrax edema toxin produces pronounced tachycardia and lethal toxin depresses left ventricular (LV) ejection fraction in in vivo models, whether these changes reflect direct cardiac effects as opposed to indirect ones related to preload or afterload alterations is unclear. In the present study, the effects of edema toxin and lethal toxin were investigated in a constant pressure isolated perfused rat heart model. Compared with control hearts, edema toxin at doses comparable to or less than a dose that produced an 80% lethality rate (LD(80)) in vivo in rats (200, 100, and 50 ng/ml) produced rapid increases in heart rate (HR), coronary flow (CF), LV developed pressure (LVDP), dP/dt(max), and rate-pressure product (RPP) that were most pronounced and persisted with the lowest dose (P ≤ 0.003). Edema toxin (50 ng/ml) increased effluent and myocardial cAMP levels (P ≤ 0.002). Compared with dobutamine, edema toxin produced similar myocardial changes, but these occurred more slowly and persisted longer. Increases in HR, CF, and cAMP with edema toxin were inhibited by a monoclonal antibody blocking toxin uptake and by adefovir, which inhibits the toxin's intracellular adenyl cyclase activity (P ≤ 0.05). Lethal toxin at an LD(80) dose (50 ng/ml) had no significant effect on heart function but a much higher dose (500 ng/ml) reduced all parameters (P ≤ 0.05). In conclusion, edema toxin produced cAMP-mediated myocardial chronotropic, inotropic, and vasodilatory effects. Vasodilation systemically with edema toxin could contribute to shock during anthrax while masking potential inotropic effects. Although lethal toxin produced myocardial depression, this only occurred at high doses, and its relevance to in vivo findings is unclear.

SB203580, a p38 inhibitor, improved cardiac function but worsened lung injury and survival during Escherichia coli pneumonia in mice.

BACKGROUND: Supporting its therapeutic application in sepsis, p38 mitogen-activated protein kinase (MAPK) inhibition decreases cardiopulmonary injury and lethality with lipopolysaccharide challenge. However, only one preclinical study has reported the survival effects of a p38 inhibitor (SB203580, 100 mg/kg) during infection. We therefore tested SB203580 in mice (n = 763) challenged with intratracheal Escherichia coli and treated with antibiotics and fluids. METHODS AND RESULTS: Compared with placebo, high dose SB203580 (100 mg/kg) pretreatment increased the hazards ratio of death (95% confidence interval) (3.6 [2.1, 6.1], p < 0.0001). Decreasing doses (10, 1, or 0.1 mg/kg) went from being harmful to having no significant effect (p < 0.0001 for the effect of decreasing dose). At 48 hours, but not 24 hours after E. coli, high and low dose SB203580 pretreatment decreased cardiac phosphorylated p38 MAPK levels and improved cardiac output either (p

Neuronal nitric oxide synthase deficiency decreases survival in bacterial peritonitis and sepsis.

OBJECTIVE: To investigate the role of neuronal nitric oxide synthase (NOS1) in murine polymicrobial peritonitis and sepsis. DESIGN: Randomized experimental trial. SETTING: Animal research facility. SUBJECTS: B6129S NOS1+/+ and B6;129S4 NOS-/- mice. INTERVENTIONS: NOS1+/+ and NOS1-/- animals underwent cecal ligation and puncture (CLP) or sham surgery and received the NOS1 inhibitor 7-nitroindazole (7-NI) or vehicle. MEASUREMENTS AND MAIN RESULTS: After CLP, genetic deficiency and pharmacologic inhibition of NOS1 significantly increased risk of mortality [8.69 (3.27, 23.1), p<0.0001 and 1.71 (1.00, 2.92) p=0.05, hazard ratio of death (95% confidence interval) for NOS1-/- and 7-NI-treated NOS1+/+ respectively] compared with NOS1+/+ animals. In 7-NI-treated NOS1+/+ animals, there were increases (6 h) and then decreases (24 h), whereas in NOS-/- animals persistent increases in blood bacteria counts (p=0.04 for differing effects of 7-NI and NOS1-/-) were seen compared with NOS1(+/+) animals. After CLP, NOS1(-/-) had upregulation of inducible NOS and proinflammatory cytokines and greater increases in serum tumor necrosis factor-alpha and interleukin-6 levels compared with NOS1+/+ mice (all p<0.05). Following CLP, there were similar significant decreases in circulating leukocytes and lung lavage cells (p

Preclinical trial of L-arginine monotherapy alone or with N-acetylcysteine in septic shock.

OBJECTIVE: L-arginine supplementation in sepsis is controversial. Septic shock has been alternatively viewed as an L-arginine-deficient state or as a syndrome caused by excess nitric oxide, an end-product of L-arginine metabolism. DESIGN: Randomized, placebo-controlled, and double-blinded (investigators, veterinarians, and pharmacists). SETTING: Laboratory. SUBJECTS: Purpose-bred, 1- to 2-yr-old, 10- to 12-kg beagles. INTERVENTIONS: The effects of parenteral L-arginine alone or in combination with N-acetylcysteine were compared with vehicle alone in a well-characterized canine model of Escherichia coli peritonitis. Two doses were studied that delivered approximately 1.5-fold (10 mg x kg(-1) x hr(-1)) and 15-fold (100 mg x kg(-1) x hr(-1)) the L-arginine dose typically administered with standard total parenteral nutrition. Animals in the low- and high-dose L-arginine arms were further randomized to receive vehicle alone or N-acetylcysteine (20 mg x kg(-1) x hr(-1)) as an antioxidant to prevent peroxynitrite formation. MEASUREMENTS AND MAIN RESULTS: The main measurements were hemodynamics, plasma arginine and ornithine, serum nitrate/nitrite, laboratory studies for organ injury, and survival. Both doses of L-arginine similarly increased mortality (p = .02), and worsened shock (p = .001 for reduced mean arterial pressure). These effects were associated with significant increases in plasma arginine (p = .0013) and ornithine (p = .0021). In addition, serum nitrate/nitrite (p = .02), liver enzymes (p = .08), and blood urea nitrogen/creatinine ratios (p = .001) rose, whereas arterial pH (p = .001) and bicarbonate levels (p = .001) fell. N-acetylcysteine did not significantly decrease any of the harmful effects of L-arginine. Thus, parenteral L-arginine monotherapy was markedly harmful in animals with septic shock. CONCLUSIONS: These findings suggest that supplemental parenteral L-arginine, at doses above standard dietary practices, should be avoided in critically ill patients with septic shock.

DTPA Fe(III) decreases cytokines and hypotension but worsens survival with Escherichia coli sepsis in rats.

OBJECTIVE: Nonselective inhibition of nitric oxide (NO) with NO synthase antagonists decreases hypotension but worsens outcome clinically. We investigated whether iron (III) complex of diethylenetriaminepentaacetic acid [DTPA Fe(III)], a scavenger of NO as well as other oxidant mediators, has similar divergent effects in E. coli challenged rats. METHODS: Animals with venous and arterial catheters and challenged with intrabronchial or intravenous E. coli were randomized to treatment with DTPA Fe(III) in doses from 3 to 800 mg/kg or placebo. Mean blood pressure (MBP) was measured in all animals and plasma NO, cytokines, and blood and lung leukocyte and bacteria counts in animals administered intrabronchial E. coli and DTPA Fe(III) 50 mg/kg or placebo. Animals received antibiotics and were observed 168 h. RESULTS: Independent of drug regimen or infection site, compared to placebo, DTPA Fe(III) increased MBP although this was greater with high vs. lower doses. Despite increased MBP, DTPA Fe(III) worsened the hazards ratio of survival . At 6 and 24 h DTPA Fe(III) decreased NO but not significantly and decreased four cytokines (tumor necrosis factor-alpha, interleukins 1 and 10, and macrophage inflammatory protein 3alpha) and lung lavage neutrophils. From 6 to 24 h DTPA Fe(III) increased blood bacteria. CONCLUSIONS: DTPA Fe(III) while increasing blood pressure has the potential to worsen outcome in sepsis. Further preclinical testing is required before this agent is applied clinically.