New and Persistent Sedative Prescriptions Among Older Adults Following a Critical Illness: A Population-Based Cohort Study.

BACKGROUND: ICU survivors often have complex care needs and can experience insufficient medication reconciliation and polypharmacy. It is unknown which ICU survivors are at risk of new sedative use posthospitalization. RESEARCH QUESTION: For sedative-naive, older adult ICU survivors, how common is receipt of new and persistent sedative prescriptions, and what factors are associated with receipt? STUDY DESIGN AND METHODS: This population-based cohort study included ICU survivors aged ≥ 66 years who had not filled sedative prescriptions within ≤ 6 months before hospitalization (sedative-naive) in Ontario, Canada (2003-2019). Using multilevel logistic regression, demographic, clinical, and hospital characteristics and their association with new sedative prescription within ≤ 7 days of discharge are described. Variation between hospitals was quantified by using the adjusted median OR. Factors associated with persistent prescriptions (≤ 6 months) were examined with a multivariable proportional hazards model. RESULTS: A total of 250,428 patients were included (mean age, 76 years; 61% male). A total of 15,277 (6.1%) filled a new sedative prescription, with variation noted across hospitals (2% [95% CI, 1-3] to 44% [95% CI, 3-57]); 8,458 (3.4%) filled persistent sedative prescriptions. Adjusted factors associated with a new sedative included: discharge to long-term care facility (adjusted OR [aOR], 4.00; 95% CI, 3.72-4.31), receipt of inpatient geriatric (aOR, 1.95; 95% CI, 1.80-2.10) or psychiatry (aOR, 2.76; 95% CI, 2.62-2.91) consultation, invasive ventilation (aOR, 1.59; 95% CI, 1.53-1.66), and ICU length of stay ≥ 7 days (aOR, 1.50; 95% CI, 1.42-1.58). The residual heterogeneity between hospitals (adjusted median OR, 1.43; 95% CI, 1.35-1.49) had a stronger association with new sedative prescriptions than the Charlson Comorbidity Index score or sepsis. Factors associated with persistent sedative use were similar with the addition of female subjects (subdistribution hazard ratio, 1.07; 95% CI, 1.02-1.13) and pre-existing polypharmacy (subdistribution hazard ratio, 0.88; 95% CI, 0.80-0.93). INTERPRETATION: One in 15 sedative-naive, older adult ICU survivors filled a new sedative within ≤ 7 days of discharge; more than one-half of these survivors filled persistent prescriptions. New prescriptions at discharge varied widely across hospitals and represent the potential value of modifying prescription practices, including medication review and reconciliation.

Pharmacokinetics of recombinant human annexin A5 (SY-005) in patients with severe COVID-19.

Objective: Annexin A5 is a phosphatidylserine binding protein with anti-inflammatory, anticoagulant and anti-apoptotic properties. Preclinical studies have shown that annexin A5 inhibits pro-inflammatory responses and improves organ function and survival in rodent models of sepsis. This clinical trial aimed to evaluate the pharmacokinetic (PK) properties of the recombinant human annexin A5 (SY-005) in severe COVID-19. Methods: This was a pilot randomized, double-blind, placebo-controlled trial. Severe COVID-19 patients were randomly assigned to receive intravenous 50 µg/kg (low dose, n = 3), 100 µg/kg (high dose, n = 5) of SY-005 or placebo (n = 5) every 12 h for 7 days. Plasma SY-005 levels were assessed using enzyme-linked immunosorbent assay (ELISA) and the PK parameters were determined using non-compartmental analysis. Results: All patients treated with SY-005 had a normal baseline estimated glomerular filtration rate (eGFR, 104-125 mL/min/1.73 m2). Both low and high doses of SY-005 were cleared within 6 h after intravenous administration. Plasma maximum concentrations (Cmax), half-life, clearance and volume distribution of low and high doses of SY-005 were 402.4 and 848.9 ng/mL, 0.92 and 0.96 h, 7.52 and 15.19 L/h, and 9.98 and 20.79 L, respectively. Daily pre-dose circulating annexin A5 levels were not significantly different when SY-005 was administered at the low or the high dose 12-h intervals. There was no significant effect on activated partial thromboplastin time (aPTT) or INR (international normalized ratio of prothrombin time) during 7 days of SY-005 treatment. Conclusion: SY-005 doses of 50 and 100 µg/kg were detectable and subsequently cleared from the plasma in severe COVID-19 patients with normal baseline renal function. There was no significant plasma SY-005 accumulation 6 h after drug administration and coagulation was not altered during 7 days of treatment. Clinical trials Registration: This study was registered with ClinicalTrials.gov (NCT04748757, first posted on 10 February 2021).

Epitope-specific antibody responses differentiate COVID-19 outcomes and variants of concern.

BACKGROUNDThe role of humoral immunity in COVID-19 is not fully understood, owing, in large part, to the complexity of antibodies produced in response to the SARS-CoV-2 infection. There is a pressing need for serology tests to assess patient-specific antibody response and predict clinical outcome.METHODSUsing SARS-CoV-2 proteome and peptide microarrays, we screened 146 COVID-19 patients' plasma samples to identify antigens and epitopes. This enabled us to develop a master epitope array and an epitope-specific agglutination assay to gauge antibody responses systematically and with high resolution.RESULTSWe identified linear epitopes from the spike (S) and nucleocapsid (N) proteins and showed that the epitopes enabled higher resolution antibody profiling than the S or N protein antigen. Specifically, we found that antibody responses to the S-811-825, S-881-895, and N-156-170 epitopes negatively or positively correlated with clinical severity or patient survival. Moreover, we found that the P681H and S235F mutations associated with the coronavirus variant of concern B.1.1.7 altered the specificity of the corresponding epitopes.CONCLUSIONEpitope-resolved antibody testing not only affords a high-resolution alternative to conventional immunoassays to delineate the complex humoral immunity to SARS-CoV-2 and differentiate between neutralizing and non-neutralizing antibodies, but it also may potentially be used to predict clinical outcome. The epitope peptides can be readily modified to detect antibodies against variants of concern in both the peptide array and latex agglutination formats.FUNDINGOntario Research Fund (ORF) COVID-19 Rapid Research Fund, Toronto COVID-19 Action Fund, Western University, Lawson Health Research Institute, London Health Sciences Foundation, and Academic Medical Organization of Southwestern Ontario (AMOSO) Innovation Fund.

The effect of aerosolized indomethacin on lung inflammation and injury in a rat model of blunt chest trauma

Background: Acute lung contusion from blunt chest trauma (BCT) is characterized by an intense inflammatory response in the pulmonary parenchyma, which is associated with acute lung injury (ALI), acute respiratory distress syndrome and ventilator-associated pneumonia. We hypothesized that aerosolized indomethacin may reduce pulmonary inflammation and ALI in a rat model of BCT. Methods: Sprague-Dawley rats were anesthetized and received a tracheotomy for administration of aerosolized medication through a catheter. The BCT procedure involved free-dropping a hollow metal weight (200 g) from a height of 25.5, 38.3 or 51.2 cm onto the right thorax. We administered 1 mg/kg of indomethacin or 1 mL/kg of saline intratracheally 15 minutes after BCT. The sham group had a similar procedure without the exposure to BCT and treatment. Three hours postimpact, we obtained arterial blood gas and analyzed bronchoalveolar lavage for protein concentration, polymorphonuclear leukocytes (PMN) and cytokine levels, and lung tissue samples were taken for histopathological analysis. Results: The rats' mean arterial pressure and heart rate dropped immediately postimpact but recovered close to that of the sham group after 30 minutes in both control and treatment groups. Compared to BCT alone, indomethacin significantly reduced the total protein level in the lungs (1.06 ± 0.39 mg/mL v. 3.75 ± 1.95 mg/mL, p = 0.006) and alveolar FD-70 leak (0.23 ± 0.19 µg/mL v. 0.53 ± 0.19 µg/mL, p = 0.02). Indomethacin also significantly attenuated the acute inflammatory response in percent PMN (13.33 ±7.5% v. 28.0 ± 12.96%, p = 0.04). Tumour necrosis factor-α and interleukin-6 decreased in the indomethacin group, but the decreases were not significant compared with other groups. Conclusion: Aerosolized indomethacin has a protective effect against alveloar tissue permeability and inflammatory response induced by BCT.

Contexte: La contusion pulmonaire aiguë causée par un traumatisme thoracique fermé (TTF) se caractérise par une intense réaction inflammatoire dans le parenchyme pulmonaire, liée à une atteinte pulmonaire aiguë (APA), à un syndrome de détresse respiratoire et à la pneumonie associée à la ventilation mécanique. Nous avons émis l'hypothèse que l'indométacine en aérosol pouvait réduire l'inflammation pulmonaire et l'APA dans un modèle murin de TTF. Méthodes: Des rats Sprague-Dawley ont été anesthésiés et ont subi une trachéotomie pour l'administration du médicament en aérosol par un cathéter. Le TTF a été infligé par un poids de métal creux (200 g) en chute libre d'une hauteur de 25,5, 38,3 ou 51,2 cm sur le thorax droit. Nous avons administré 1 mg/kg d'indométacine ou 1 mL/kg de solution saline dans la trachée 15 minutes après le TTF. Un groupe a été soumis à une intervention similaire fictive, sans exposition au TTF ni au traitement. Trois heures après l'impact, nous avons obtenu des gaz artériels et analysé le liquide de lavage bronchoalvéolaire pour connaître les taux de protéines, de leucocytes polymorphonucléaires (PMN) et de cytokines; nous avons aussi prélevé des échantillons de tissu pulmonaire pour des analyses histopathologiques. Résultats: La pression artérielle et la fréquence cardiaque moyennes des rats ont immédiatement chuté après l'impact, mais sont revenues près des valeurs du groupe soumis à l'intervention fictive après 30 minutes dans le groupe témoin et le groupe traité. Comparativement au TTF seul, l'indométacine a significativement réduit le taux de protéines totales dans les poumons (1,06 ± 0,39 mg/mL c. 3,75 ± 1,95 mg/mL, p = 0,006) et la fuite alvéolaire de FD-70 (0,23 ± 0,19 µg/mL c. 0,53 ± 0,19 µg/mL, p = 0,02). L'indométacine a aussi significativement atténué la réaction inflammatoire aiguë en pourcentage de PMN (13,33 ±7,5 % c. 28,0 ± 12,96 %, p = 0,04). Le facteur de nécrose tumorale α et l'interleukine-6 ont diminué dans le groupe sous indométacine, mais ces baisses n'ont pas été significatives comparativement aux autres groupes. Conclusion: L'indométacine en aérosol exerce un effet protecteur contre la perméabilité du tissu alvéolaire et la réaction inflammatoire induite par le un TTF.

Agreement between venous and arterial blood gas analysis of acid-base status in critical care and ward patients: a retrospective cohort study.

PURPOSE: To determine whether the use of venous blood gases can be a suitable alternative to arterial sampling to evaluate acid-base status. METHODS: The database of the clinical laboratory in a large academic hospital was searched for records of venous blood gas analysis and an arterial sample taken within ten minutes from the same patient. Bland-Altman analyses of pH, pCO2, and lactate were performed for samples obtained from patients separately from within and outside the intensive care unit (ICU). RESULTS: In 2,296 paired arterial-venous samples from 351 ICU patients, the bias was 0.044, -6.2 mmHg, and -0.07 mEq·L-1 for pH, pCO2, and lactate, respectively. The range of agreement centred on this bias (upper minus lower level of agreement) was 0.134, 16.7 mmHg, and 1.35 mEq·L-1 for pH, pCO2, and lactate, respectively. Intraclass correlation coefficients (ICCs) were 0.79, 0.76, and 0.99 for pH, pCO2, and lactate, respectively, indicating excellent agreement. Multiple samples obtained from the same patient had a median standard deviation of 0.02, 2.77 mmHg, and 0.18 mEq·L-1 for pH, pCO2, and lactate, respectively. Similar agreement was observed in samples from patients outside the ICU, although the ICC was only 0.53 for pCO2. CONCLUSIONS: Venous gases are suitable for initial evaluation of acid-base status in critically ill patients. Based on clinical evaluation, an arterial sample may then be considered for confirmation, and thereafter, venous blood gases could be sufficient for monitoring response to treatment.

C-peptide attenuates acute lung inflammation in a murine model of hemorrhagic shock and resuscitation by reducing gut injury.

BACKGROUND: The study aims to evaluate whether C-peptide can reduce gut injury during hemorrhagic shock (HS) and resuscitation (R) therefore attenuate shock-induced inflammation and subsequent acute lung injury. METHODS: Twelve-week-old male mice (C57/BL6) were hemorrhaged (mean arterial blood pressure maintained at 35 mm Hg for 60 minutes) and then resuscitated with Ringer's lactate, followed by red blood cell transfusion with (HS/R) or without C-peptide (HS/R + C-peptide). Mouse gut permeability, bacterial translocation into the circulatory system and intestinal pathology, circulating HMGB1, and acute lung injury were assessed at different times after R. The mice in the control group underwent sham procedures without HS. RESULTS: Compared to the sham group, the mice in the HS/R group showed increased gut permeability (6.07 ± 3.41 µg of FD4/mL) and bacterial translocation into the circulatory system (10.05 ± 4.92, lipopolysaccharide [LPS] of pg/mL), and increased gut damage; conversely, mice in the HS/R + C-peptide group showed significantly reduced gut permeability (1.59 ± 1.39 µg of FD4/mL; p < 0.05) and bacterial translocation (4.53 ± 1.08 pg of LPS/mL; p < 0.05) with reduced intestine damage. In addition, mice in the HS/R group had increased circulating HMGB1 (21.64 ± 14.17 ng/mL), lung myeloperoxidase) activity (34.4 ± 8.91 mU/g of tissue), and pulmonary protein leakage (2.33 ± 1.16 µg Evans blue/g tissue per minute). Mice in the HS/R + C-peptide group showed decreased HMGB1 (7.27 ± 1.93 ng/mL; p < 0.05), lung myeloperoxidase (23.73 ± 8.39 mU/g of tissue; p < 0.05), and pulmonary protein leakage (1.17 ± 0.42 Evans Blue/g tissue per minute; p < 0.05). CONCLUSION: Our results indicate that C-peptide exerts beneficial effects to attenuate gut injury and dysfunction, therefore diminishing lung inflammation and subsequent injury in mice with HS and R.

Carbon monoxide releasing molecule-3 improves myocardial function in mice with sepsis by inhibiting NLRP3 inflammasome activation in cardiac fibroblasts.

The NLRP3 inflammasome is an intracellular multiple-protein complex that controls the maturation and release of interleukin (IL)-1ß and IL-18. Endogenous carbon monoxide (CO) is anti-inflammatory. The aim of this study was to assess the effects/mechanisms of CO-releasing molecule-3 (CORM-3)-dependent modulation of the NLRP3 inflammasome in cardiac fibroblasts (CF) and its effect on myocardial function in sepsis. CF were treated with CORM-3 or inactive CORM-3 (iCORM-3) before NLRP3 inflammasome priming with lipopolysaccharides (LPS) or following activation with adenosine triphosphate (ATP). In parallel, cardiomyocytes (CM) were challenged with supernatants of LPS/ATP-stimulated CF or a cytokine mixture (Cyto-mix) containing IL-1ß, IL-18, and HMGB1. In vivo, mice were treated with CORM-3 before or after LPS to induce sepsis (endotoxemia). Pretreatment of CF with CORM-3 prevented an LPS-induced increase in NLRP3 and pro-IL-1ß expression. Treatment of CF with CORM-3 before ATP prevented ATP-induced activation of the NLRP3 inflammasome. Challenging CF with LPS/ATP promoted NLRP3 interactions with adaptor ASC (apoptosis-associated speck-like protein containing a caspase-recruitment domain), which was prevented by CORM-3. Challenging CM with supernatants of CF with LPS/ATP or Cyto-mix (IL-1ß, IL-18, and HMGB1) resulted in CM apoptosis, which was attenuated with either a CORM-3 or IL-1 receptor antagonist. Finally, myocardial NLRP3 inflammasome activation and myocardial dysfunction in septic mice were abolished by CORM-3. In NLRP3-deficient mice with sepsis, CORM-3 did not show additional benefits in improving myocardial function. Our results indicate that CORM-3 suppresses NLRP3 inflammasome activation by blocking NLRP3 interactions with the adaptor protein ASC and attenuates myocardial dysfunction in mice with sepsis.

Cardiac fibroblasts contribute to myocardial dysfunction in mice with sepsis: the role of NLRP3 inflammasome activation.

Myocardial contractile dysfunction in sepsis is associated with the increased morbidity and mortality. Although the underlying mechanisms of the cardiac depression have not been fully elucidated, an exaggerated inflammatory response is believed to be responsible. Nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome is an intracellular platform that is involved in the maturation and release of interleukin (IL)-1ß. The aim of the present study is to evaluate whether sepsis activates NLRP3 inflammasome/caspase-1/IL-1ß pathway in cardiac fibroblasts (CFs) and whether this cytokine can subsequently impact the function of cardiomyocytes (cardiac fibroblast-myocyte cross-talk). We show that treatment of CFs with lipopolysaccharide (LPS) induces upregulation of NLRP3, activation of caspase-1, as well as the maturation (activation) and release of IL-1ß. In addition, the genetic (small interfering ribonucleic acid [siRNA]) and pharmacological (glyburide) inhibition of the NLRP3 inflammasome in CFs can block this signaling pathway. Furthermore, the inhibition of the NLRP3 inflammasome in cardiac fibroblasts ameliorated the ability of LPS-challenged CFs to impact cardiomyocyte function as assessed by intracellular cyclic adenosine monophosphate (cAMP) responses in cardiomyocytes. Salient features of this the NLP3 inflammasome/ caspase-1 pathway were confirmed in in vivo models of endotoxemia/sepsis. We found that inhibition of the NLRP3 inflammasome attenuated myocardial dysfunction in mice with LPS and increased the survival rate in mice with feces-induced peritonitis. Our results indicate that the activation of the NLRP3 inflammasome in cardiac fibroblasts is pivotal in the induction of myocardial dysfunction in sepsis.

A prospective determination of the incidence of perceived inappropriate care in critically ill patients.

BACKGROUND: Health care providers' perceptions regarding appropriateness in end-of-life treatments have been widely studied. While nurses and physicians believe that rationing and other cost-related practices sometimes occur in the intensive care unit (ICU), they allege that treatment is often excessive. OBJECTIVE: To prospectively determine the incidence and causes of health care providers' perceptions regarding appropriateness of end-of-life treatments. METHODS: The present prospective study collected data from patients admitted to the medical-surgical trauma ICU of a 30-bed, Canadian teaching hospital over a three-month period. Daily surveys were completed independently by bedside nurses, charge nurses and attending physician. RESULTS: In total, 5224 of 6558 expected surveys (representing 294 patients) were analyzed, yielding a response rate of 79.7%. The incidence of perceived inappropriate care in the present study was 6.5% (19 of 294 patients), with ongoing treatment for >2 days after this determination occurring in 1% (three of 294 patients). However, at least one caregiver perceived inappropriate care at some point in 110 of 294 (37.5%) patients. In these cases, in which processes to address care were not already underway, respondents believed that important issues resulting in provision of inappropriate treatments included patient-family issues and communication before or in the ICU. Caregivers did not know their patients' wishes 22% (1129 of 5224) of the time. CONCLUSIONS: Although ongoing inappropriate care appeared to be a rare occurrence, the issue was a concern to at least one caregiver in one-third of cases. Public awareness for end-of-life issues, adequate communication, and up-to-date knowledge and practice in determining the wishes of critically ill patients are potential target areas to improve end-of-life care and reduce inappropriate care in the ICU. A daily, prospective survey of multidisciplinary caregivers, such as the survey used in the present study, is a viable and valuable means of determining the scope and causes of inappropriate care in the ICU.

Effect of cardiopulmonary bypass on thrombin generation and protein C pathway.

OBJECTIVE: The purpose of this study was to evaluate the mechanisms of cardiopulmonary bypass (CPB)-induced dysregulation between thrombin and its regulatory anticoagulant activated protein C (APC). DESIGN: A prospective observational cohort study. SETTING: A tertiary care university hospital and associated research laboratory. PATIENTS: Twenty patients undergoing elective coronary artery bypass surgery with (n = 10) or without CPB (n = 10). INTERVENTIONS: Blood samples were collected at 7 time points: preinduction; after heparin; 1 hour after the institution of CPB (or the completion of distal anastomoses in off-CPB group); after protamine; and at 0, 4, and 18 hours in the Intensive care unit (ICU). Samples were analyzed for prothrombin fragments (F1+2), thrombin-antithrombin complexes, protein C (PC), APC, soluble thrombomodulin (sTM), and soluble endothelial protein C receptor (sEPCR). MEASUREMENTS AND MAIN RESULTS: F1+2 levels increased significantly 1 hour after the initiation of CPB in comparison with baseline (2.7 ± 0.5 v 0.5 ± 0.2 nmol/L, p < 0.001) (mean ± standard deviation) and remained elevated until 4 hours after ICU admission (p < 0.001). In contrast, APC levels did not show any significant changes over time in either group. sEPCR, sTM, and PC levels did not change during CPB although sEPCR decreased significantly after the termination of CPB compared with baseline in the CPB group. CONCLUSIONS: Exposure to CPB is associated with a distinct thrombin surge that continues postoperatively for 4 hours. The impaired ability to generate APC reflects a complex process that is not associated with increased levels of sEPCR and thrombomodulin during CPB. Further studies are required to evaluate the regulation of the host APC response in cardiac surgery.

Recombinant human erythropoietin improves gut barrier function in a hemorrhagic shock and resuscitation rat model.

BACKGROUND: Gut injury and bacterial translocation develop and persist after limited periods of hemorrhagic shock. Erythropoietin (EPO) can exert hemodynamic, anti-inflammatory, and tissue protective effects. We tested the hypothesis that EPO given at the time of resuscitation with saline will reduce functional ileal injury 24 hours after shock. METHODS: Sprague-Dawley rats (n = 6 per group) were randomized to sham surgery or hemorrhagic shock maintained at mean arterial pressure 40 mm Hg for 60 minutes and then treated with either saline resuscitation (three times the volume of shed blood) or saline + recombinant human EPO (rHuEPO) resuscitation. Intravenous rHuEPO (1,000 U/kg) was given at the start of saline resuscitation, and at 24 hours ileal function was evaluated using quantitative cultures of mesenteric lymph nodes to assess for bacterial translocation (colony-forming units per gram of tissue [CFU/g]), determination of portal vein plasma endotoxin levels and histopathological evaluation using semi-thin plastic sections of the distal ileum. In a second series of animals, fluorescein isothiocyanate-dextran 4000 (FD-4) was used to assess mucosal permeability of the distal ileum to macromolecules. RESULTS: At 24 hours, the saline group had morphologic evidence of intestinal injury when compared with the sham group, and the degree of mucosal injury was less in the saline + rHuEPO when compared with the saline group, which demonstrated significantly reduced bacterial translocation to the mesenteric lymph nodes (383 CFU/g ± 111 CFU/g vs. 1130 CFU/g ± 297 CFU/g; p < 0.05) and decreased terminal ileum permeability to FD-4 (3.08 µg/mL ± 0.31 µg/mL vs. 5.14 µg/mL ± 0.88 µg/mL; p < 0.05). No significant difference was found in the portal vein endotoxin levels between the two groups. Histopathological evaluation demonstrated a trend for decreased enterocyte disarray or disruption and vacuolization in the saline + rHuEPO versus saline group. CONCLUSION: Using rHuEPO at time of saline resuscitation resulted in decreased bacterial translocation and permeability to macromolecules 24 hours after shock. These observations suggest that rHuEPO can mediate a protective effect on intestinal mucosal barrier function during ischemic injury.

Endogenous HMGB1 contributes to ischemia-reperfusion-induced myocardial apoptosis by potentiating the effect of TNF-α/JNK.

High-mobility group box 1 (HMGB1) is a nuclear protein that has been implicated in the myocardial inflammation and injury induced by ischemia-reperfusion (I/R). The purpose of the present study was to assess the role of HMGB1 in myocardial apoptosis induced by I/R. In vivo, myocardial I/R induced an increase in myocardial HMGB1 expression and apoptosis. Inhibition of HMGB1 (A-box) ameliorated the I/R-induced myocardial apoptosis. In vitro, isolated cardiac myocytes were challenged with anoxia-reoxygenation (A/R; in vitro correlate to I/R). A/R-challenged myocytes also generated HMGB1 and underwent apoptosis. Inhibition of HMGB1 attenuated the A/R-induced myocyte apoptosis. Exogenous HMGB1 had no effect on myocyte apoptosis. However, inhibition of HMGB1 attenuated myocyte TNF-α production after the A/R was challenged; surprisingly, HMGB1 itself did not induce myocyte TNF-α production. Exogenous TNF-α induced a moderate proapoptotic effect on the myocytes, an effect substantially potentiated by coadministration of HMGB1. It is generally accepted that apoptosis induced by TNF-α is regulated by the balance of activation of c-Jun NH(2)-terminal kinase (JNK) and NF-κB. Indeed, in the present study, TNF-α increased the phosphorylation status of JNK and p65, a subunit of NF-κB; HMGB1 greatly potentiated TNF-α-induced JNK phosphorylation. Furthermore, inhibition of JNK (SP-600125) prevented the myocyte apoptosis induced by a TNF-α/HMGB1 cocktail. Finally, A/R increased HMGB1 production in both wild-type and toll-like receptor 4-deficient myocytes; however, deficiency in toll-like receptor 4 diminished A/R-induced myocyte apoptosis, TNF-α, and JNK activation. Our results indicate that myocyte-derived HMGB1 and TNF-α work in concert to promote I/R-induced myocardial apoptosis through JNK activation.

The alarmin cytokine, high mobility group box 1, is produced by viable cardiomyocytes and mediates the lipopolysaccharide-induced myocardial dysfunction via a TLR4/phosphatidylinositol 3-kinase gamma pathway.

High mobility group box 1 (HMGB1) is an alarmin actively secreted by immune cells and passively released by necrotic nonimmune cells. HMGB1 has been implicated in both cardiac contractile dysfunction and the lethality associated with sepsis/endotoxemia. The aim of the current study was to assess whether viable cardiomyocytes could produce HMGB1 and whether HMGB1 can affect myocardial contractility. LPS was used as a model of sepsis/endotoxemia in mice and isolated cardiac myocytes. LPS increased myocardial expression of HMGB1 in vivo (immunohistochemistry) and production and secretion of HMGB1 by viable cardiac myocytes in vitro (Western). LPS increased the phosphorylation status of PI3Kgamma in cardiac myocytes, an effect not observed in TLR4(-/-) myocytes. Genetic (PI3Kgamma(-/-)) or pharmacologic (AS605240) blockade of PI3Kgamma ameliorated the LPS-induced 1) cardiomyocyte production and secretion of HMGB1 in vitro and 2) HMGB1 expression in the myocardium in vivo. The LPS-induced depression of myocardial contractility was prevented by the HMGB1 antagonist, A-box. Genetic (PI3Kgamma(-/-)) or pharmacologic (AS605240) blockade of PI3Kgamma ameliorated the LPS-induced decrease in myocardial contractility. No evidence of inflammatory infiltrate was noted in any of the in vivo studies. The findings of the current study indicate that 1) LPS can induce HMGB1 secretion by viable cardiac myocytes through a TLR4/PI3Kgamma signaling pathway, and 2) HMGB1 plays a role in the LPS-induced myocardial contractile dysfunction. The results of the current study also have broader implications (i.e., that viable parenchymal cells, such as cardiac myocytes, participate in the alarmin response).

NADPH oxidase contributes to conversion of cardiac myocytes to a proinflammatory phenotype in sepsis.

It has been reported that polymorphonuclear leukocyte (PMN) infiltration into the myocardial interstitium is involved in sepsis-induced myocardial dysfunction. The aim of this study was to evaluate the role of NADPH oxidase in the sepsis-induced conversion of cardiomyocytes to a proinflammatory phenotype. Using an in vitro approach we evaluated the role of NADPH oxidase in cardiomyocyte CXC chemokine production and its ability to promote PMN transendothelial migration under septic conditions. Treatment of cardiac myocytes with septic plasma (1) activated NADPH oxidase (p47phox phosphorylation) and increased its activity (O(2)(-) production) and (2) converted them to a proinflammatory phenotype; both effects were prevented by blockade of NADPH oxidase. NF-kappaB nuclear translocation was increased in cardiomyocytes conditioned with septic plasma, a response prevented by blockade of NADPH oxidase. The increase in NF-kappaB activation/translocation was associated with phosphorylation of both IKK and the p65 subunit of NF-kappaB. Blockade of NADPH oxidase prevented phosphorylation of IKK, but not p65. Blockade approaches indicated that p38 MAP kinase (previously implicated in NF-kappaB activation) did not play a role in the NADPH oxidase pathway, either upstream or downstream. Collectively, the results of this study and those of previous reports indicate that the conversion of cardiomyocytes to a proinflammatory phenotype in sepsis involves two distinct pathways: NADPH oxidase-mediated phosphorylation of IKK and p38 MAP kinase-mediated phosphorylation of p65.

Impact of intensive care unit discharge time on patient outcome.

OBJECTIVE: To determine the impact of nighttime intensive care unit (ICU) discharge on patient outcome. DESIGN: Multiple-center, retrospective observational cohort study. SETTING: Canadian hospitals. PATIENTS: We used a prospectively collected dataset containing information on 79,090 consecutive admissions from 31 Canadian community and teaching hospitals. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were categorized according to the time of ICU discharge into daytime (07:00-20:59) and nighttime (21:00-06:59). Admissions were excluded if the patients were a)

Perioperative N-acetylcysteine to prevent renal dysfunction in high-risk patients undergoing cabg surgery: a randomized controlled trial.

CONTEXT: Renal dysfunction is a complication of coronary artery bypass graft (CABG) surgery performed with cardiopulmonary bypass (CPB) that is associated with increased morbidity and mortality. N-acetylcysteine, an antioxidant and vasodilator, counteracts renal ischemia and hypoxia. OBJECTIVE: To determine whether perioperative intravenous (IV) N-acetylcysteine preserves renal function in high-risk patients undergoing CABG surgery with CPB compared with placebo. DESIGN, SETTING, AND PATIENTS: Randomized, quadruple blind, placebo-controlled trial (October 2003-September 2004) in operating rooms and general intensive care units (ICUs) of 2 Ontario tertiary care centers. The 295 patients required elective or urgent CABG and had at least 1 of the following: preexisting renal dysfunction, at least 70 years old, diabetes mellitus, impaired left ventricular function, or undergoing concomitant valve or redo surgery. INTERVENTIONS: Patients received 4 (2 intraoperative and 2 postoperative) doses of IV N-acetylcysteine (600 mg) (n = 148) or placebo (n = 147) over 24 hours. MAIN OUTCOME MEASURES: The primary outcome was the proportion of patients developing postoperative renal dysfunction, defined by an increase in serum creatinine level greater than 0.5 mg/dL (44 micromol/L) or a 25% increase from baseline within the first 5 postoperative days. Secondary outcomes included postoperative interventions and complications, the requirement for renal replacement therapy (RRT), adverse events, hospital mortality, and ICU and hospital length of stay. RESULTS: There was no difference in the proportion of patients with postoperative renal dysfunction (29.7% vs 29.0%, P = .89; relative risk [RR], 1.03 [95% confidence interval {CI}, 0.72-1.46]) in the N-acetylcysteine and placebo groups, respectively. We noted nonsignificant differences in postoperative interventions and complications, the need for RRT (0.7% vs 2.1%; P = .37), total (6.1% vs 9.6%; P = .26) and serious adverse events, hospital mortality (3.4% vs 2.7%; P>.99), and ICU and hospital length of stay between the N-acetylcysteine and placebo groups. A post hoc subgroup analysis of patients (baseline creatinine level >1.4 mg/dL [120 micromol/L]) showed a nonsignificant trend toward fewer patients experiencing postoperative renal dysfunction in the N-acetylcysteine group compared with the placebo group (25.0% vs 37.1%; P = .29). CONCLUSIONS: N-acetylcysteine did not prevent postoperative renal dysfunction, interventions, complications, or mortality in high-risk patients undergoing CABG surgery with CPB. Further research is required to identify CABG patients at risk for postoperative renal events, valid markers of renal dysfunction, and to establish renal thresholds associated with important clinical outcomes.