Olga Livaditi

Plasma pro- and anti-inflammatory cytokine levels and outcome prediction in unselected critically ill patients

PURPOSE To determine the inter-relationships between cytokine levels and physiological scores in predicting outcome in unselected, critically ill patients. METHODS To this end, 127 patients (96 men), having a mean+/-SD age of 45+/-20 years, with a wide range in admission diagnoses (medical, surgical, and multiple trauma patients) were prospectively investigated. Severity of critical illness and organ dysfunction were graded by acute physiology and chronic health evaluation (APACHE II) and sequential organ failure assessment (SOFA) scores, respectively. Blood samples were drawn on admission in the ICU to determine pro- and anti-inflammatory cytokines, including tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8, and IL-10. The main outcome measure was 28-day mortality. RESULTS Overall, 88 patients survived and 39 patients died. Univariate logistic regression analysis showed that SOFA, APACHE II, IL-8, IL-6, and IL-10 on admission in the ICU were related to mortality. Multiple logistic regression analysis in the entire cohort of critically ill patients revealed that SOFA (OR=1.341, p<0.001) and IL-6 (OR=1.075, p=0.01) constituted independent outcome predictors. receiver operator characteristics curve analysis showed that SOFA, APACHE II, and IL-6 had the highest area under the curve values. IL-6 correlated with APACHE II (r(s)=0.44, p<0.0001) and SOFA (r(s)=0.40, p<0.0001) scores. CONCLUSIONS In mixed ICU patients cytokine concentrations on admission in the ICU represent independent outcome predictors in the presence of disease severity scores.

The level of hypotension during hemorrhagic shock is a major determinant of the post-resuscitation systemic inflammatory response: an experimental study

BackgroundTo evaluate whether the level of hypotension during hemorrhagic shock may influence the oxidative and inflammatory responses developed during post-ischemic resuscitation.MethodsFifteen rabbits were equally allocated into three groups: sham-operated (group sham); bled within 30 minutes to mean arterial pressure (MAP) of 40 mmHg (group shock-40); bled within 30 minutes to MAP of 30 mmHg (group shock-30). Shock was maintained for 60 min. Resuscitation was performed by reinfusing shed blood with two volumes of Ringers lactate and blood was sampled for estimation of serum levels aminotransferases, creatinine, TNF-α, IL-1β, IL-6, malondialdehyde (MDA) and total antioxidant status (TAS) and for the determination of oxidative burst of polymorhonuclears (PMNs) and mononuclear cells (MCs).ResultsSerum AST of group shock-30 was higher than that of group shock-40 at 60 and 120 minutes after start of resuscitation; serum creatinine of group shock-30 was higher than group shock-40 at 120 minutes. Measured cytokines, MDA and cellular oxidative burst of groups, shock-40 and shock-30 were higher than group sham within the first 60 minutes after start of resuscitation. Serum concentrations of IL-1β, IL-6 and TNF-α of group shock-30 were higher than group shock-40 at 120 minutes (p < 0.05). No differences were found between two groups regarding serum MDA and TAS and oxidative burst on PMNs and MCs but both groups were different to group sham.ConclusionThe level of hypotension is a major determinant of the severity of hepatic and renal dysfunction and of the inflammatory response arising during post-ischemic hemorrhagic shock resuscitation. These findings deserve further evaluation in the clinical setting.

Hypoxemic resuscitation prevents pulmonary capillary endothelial dysfunction induced by normoxemic resuscitation from hemorrhagic shock

Objective:Hypoxemic reperfusion attenuates brain injury secondary to severe cerebral ischemia, myocardial, and intestinal injury occurring in intestinal postischemic shock, and offers hemodynamic stabilization and attenuation of inflammatory response when applied in the resuscitation from hemorrhagic shock. In this study, we sought to investigate the effect of hypoxemic resuscitation on pulmonary endothelium. Design:Prospective, randomized, controlled animal study. Setting:Experimental laboratory of a university intensive care unit. Subjects:Male New Zealand White rabbits weighting 3–3.5 kg. Interventions:Hemorrhagic shock at mean arterial pressure of 40 mm Hg was induced by exsanguinations in anesthetized, mechanically ventilated animals for 60 minutes and thereafter rabbits were resuscitated by homologous blood and Ringer’s lactate infusion under normoxemia (Normox-Res group, Pao2 = 95–105 mm Hg, n = 9) or hypoxemia (Hypox-Res group, Pao2 = 35–40 mm Hg, n = 7). Measurements and Main Results:Using indicator-dilution techniques we measured at baseline and post resuscitation pulmonary capillary endothelial angiotensin converting enzyme activity expressed as percentage of metabolism (%M) and hydrolysis (v) of the substrate 3H-benzoyl-Phe-Ala-Pro. Normox-Res rabbits exhibited decreased %M (p < 0.05) and v (p < 0.05) post resuscitation as compared with baseline, while no differences occurred in the Hypox-Res group. Myeloperoxidase was measured in lung tissue and was higher in Normox-Res than Hypox-Res animals (p < 0.01). Lung injury was estimated microscopically, whereas the expression of the intercellular adhesion molecule-1 and the vascular cell adhesion molecule-1 were assessed by immunohistochemistry on sections coming from the same tissue block. Compared with Normox-Res, Hypox-Res animals exhibited lower lung injury histopathological score (p < 0.01) and lung malondialdehyde concentration (p < 0.01), and lower intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expressions in both the inflammatory cells (p < 0.01) and the blood vessels (p < 0.05). Conclusions:Normoxemic resuscitation of hemorrhagic shock is associated with pulmonary endothelial dysfunction and lung injury that may be attenuated by hypoxemic resuscitation.

Exhaled Breath Condensate in Mechanically Ventilated Brain-injured Patients with No Lung Injury or Sepsis

BACKGROUND The inflammatory influence of prolonged mechanical ventilation in uninjured lungs remains a matter of controversy and largely unexplored in humans. The authors investigated pulmonary inflammation by using exhaled breath condensate (EBC) in mechanically ventilated, brain-injured patients in the absence of acute lung injury or sepsis and explored the potential influence of positive end-expiratory pressure (PEEP). METHODS Inflammatory EBC markers were assessed in 27 mechanically ventilated, brain-injured patients with neither acute lung injury nor sepsis and in 12 healthy and 8 brain-injured control subjects. Patients were ventilated with 8 ml/kg during zero end-expiratory pressure (ZEEP group, n = 12) or 8 cm H(2)O PEEP (PEEP group, n = 15). EBC was collected on days 1, 3, and 5 of mechanical ventilation to measure pH; interleukins (IL)-10, 1β, 6, 8, and 12p70; and tumor necrosis factor-α. RESULTS EBC pH was lower, whereas IL-1β and tumor necrosis factor-α were greater in both patient groups compared with either control group; IL-6 was higher, whereas IL-10 and IL-12p70 were sporadically higher than in healthy control subjects; no differences were noted between the two patient groups, except for IL-10, which decreased by day 5 during PEEP. Leukocytes, soluble IL-6, and soluble triggering receptor expressed on myeloid cells-1 in blood were constantly higher during zero end-expiratory pressure; EBC cytokines appeared mostly related to soluble IL-8 and inversely related to soluble triggering receptor expressed on myeloid cells-1. CONCLUSIONS In brain-injured, mechanically ventilated patients with neither acute lung injury nor sepsis, EBC markers appear to indicate the presence of subtle pulmonary inflammation that is mostly unaffected by PEEP. There is evidence for a systemic inflammatory response, especially in patients during zero end-expiratory pressure.

Longitudinal Assessment of Adrenal Function in the Early and Prolonged Phases of Critical Illness in Septic Patients: Relations to Cytokine Levels and Outcome

CONTEXT Adrenal dysfunction remains a controversial issue in critical care. The long-stay intensive care unit (ICU) population may be at increased risk of adrenal insufficiency. OBJECTIVE We aimed to determine whether adrenal dysfunction develops during the course of sepsis. DESIGN This is a prospective observational longitudinal study. SETTING The study was conducted in the ICU of a secondary/tertiary care hospital. PATIENTS We studied 51 consecutive mechanically ventilated patients with sepsis. INTERVENTION We measured cortisol, ACTH, cortisol-binding globulin, cytokines, and cortisol 30 minutes after 1 μg ACTH(1-24), upon sepsis diagnosis and every 3 to 4 days, until Day 30 or until recovery or death. MAIN OUTCOME MEASURES We looked for changes in baseline and stimulated cortisol levels and its relationship to ACTH levels, sepsis severity or survival. RESULTS Baseline and stimulated cortisol levels did not vary significantly. Septic patients with shock had higher baseline (20 ± 6 vs 17 ± 5 μg/dL, P = .03) and stimulated cortisol levels (26 ± 5 vs 23 ± 6 μg/dL, P = .04), compared with those without shock. On Day 1, ACTH levels could not predict cortisol levels (R(2) = 0.06, P = .08). ACTH levels increased significantly after Day 10 and, at this time point, they related to cortisol levels (R(2) = 0.35, P < .001). Development of septic shock, or resolution from it, was not associated with changes in baseline, stimulated cortisol levels, or the cortisol increment. There was much inpatient variability in the diagnosis of adrenal dysfunction at different time points. CONCLUSIONS Total cortisol levels relate both to the severity and outcome of sepsis and remain fairly unchanged during the course of illness. Initially, cortisol levels are largely ACTH independent, whereas ACTH increases and correlates with cortisol levels later on. Adrenal dysfunction does not seem to be a major problem during the prolonged phase of sepsis. Although not significant, the variation in cortisol levels may be such that classification of patients varies, questioning the utility of arbitrary cut-offs to define adrenal dysfunction in septic patients.

Hypoxemic resuscitation from hemorrhagic shock prevents lung injury and attenuates oxidative response and IL-8 overexpression

We investigated whether hypoxemic resuscitation from hemorrhagic shock prevents lung injury and explored the mechanisms involved. We subjected rabbits to hemorrhagic shock for 60 min by exsanguination to a mean arterial pressure of 40 mm Hg. By modifying the fraction of the inspired oxygen, we performed resuscitation under normoxemia (group NormoxRes, P(a)O(2)=95-105 mm Hg) or hypoxemia (group HypoxRes, P(a)O(2)=35-40 mm Hg). Animals not subjected to shock constituted the sham group (P(a)O(2)=95-105 mm Hg). We performed bronchoalveolar lavage (BAL) fluid, lung wet-to-dry weight ratio, and morphological studies. U937 monocyte-like cells were incubated with BAL fluid from each group. Cell peroxides, malondialdehyde, proteins, and cytokines in the BAL fluid were lower in sham than in shocked animals and in HypoxRes than in NormoxRes animals. The inverse was true for ascorbic acid and reduced glutathione. Lung edema, lung neutrophil infiltration, myeloperoxidase, and interleukin (IL)-8 gene expression were reduced in lungs of HypoxRes compared with NormoxRes animals. A colocalized higher expression of IL-8 and nitrotyrosine was found in lungs of NormoxRes animals compared to HypoxRes animals. The BAL fluid of NormoxRes animals compared with HypoxRes animals exerted a greater stimulation of U937 monocyte-like cells for proinflammatory cytokine release, particularly for IL-8. In the presence of p38-MAPK and Syk inhibitors and monosodium urate crystals, IL-8 release was reduced. We conclude that hypoxemic resuscitation from hemorrhagic shock ameliorates lung injury and reduces oxygen radical generation and lung IL-8 expression.

Ex-vivo effect of dexamethasone on cytokine production from whole blood of septic patients: Correlation with disease severity

BACKGROUND Controversial findings of former clinical trials on the effect of low dose hydrocortisone in patients with septic shock led to investigate the effect of corticosteroids on the production of cytokines from endotoxin (LPS)-stimulated whole blood. METHODS Whole blood from 33 septic patients was sampled within 24h alter diagnosis. Hydrocortisone was not administered during follow-up. Whole blood was stimulated with 30 ng/ml of LPS in the presence of 0.01, 0.1, 1 and 10 microM of dexamethasone. Concentrations of cytokines and of sTREM-1 were estimated in supernatants after six hours of incubation. RESULTS Dexamethasone inhibited LPS-stimulated release of TauNuFalpha, of IL-6, of IL-8 and of IL-10 in dose-dependent manner. A dual effect on the kinetics of release of IL-1beta and of sTREM-1 was shown. Release of IL-1beta was either decreased, what was connected with unfavorable outcome, or it was unaffected what was connected with a favorable outcome. Release of sTREM-1 was either increased, what was connected with unfavorable outcome, or it was decreased what was connected with a favorable outcome. CONCLUSIONS Part of the beneficiary effect of corticosteroids in sepsis may be due to an effect on the release of IL-1beta and of sTREM-1. This effect does not seem to be homogeneous for all septic patients.

Stimulation of monocytes is a pathway involved in systemic inflammatory response following haemorrhagic shock resuscitation: the effect of hypoxaemic resuscitation.

The present study was designed to investigate whether serum of animals subjected to hypoxaemic resuscitation from haemorrhagic shock may be a weak stimulant for monocytes or not. Twenty rabbits were subjected to haemorrhagic shock after blood exsanguination; resuscitation was performed by infusion of the shed blood in eight rabbits under normoxaemic conditions (NormoxRes) and in 12 under hypoxaemic conditions (HypoxRes); seven rabbits were subjected to sham operation. Malondialdehyde (MDA) and tumour necrosis factor (TNF)‐α were estimated in serum at serial time intervals; the serum was applied for stimulation of U937 monocytes with or without the p38 mitogen‐activated protein kinase (MAPK) inhibitor SB203580. Expression of triggering receptor expressed on myeloid cells‐1 (TREM‐1) on U937 was also assessed by flow cytometric analysis. Death supervened in four animals of the NormoxRes (50%) and in one animal of the HypoxRes group (8·33%, P: 0·032). Serum levels of TNF‐α and MDA were higher in NormoxRes compared to HypoxRes animals. Expression of TREM‐1 on U937 monocytes was similar after stimulation with serum sampled from both groups. Concentrations of interleukin (IL)‐1β, IL‐6 and IL‐8 of monocyte supernatants were higher after stimulation with serum of NormoxRes than HypoxRes rabbits. Production of cytokines after stimulation with serum was decreased significantly after addition of SB203580. It is concluded that stimulation of monocytes may contribute to the generation of the systemic inflammatory response during reperfusion after ischaemia. Lower stimulation of the p38 MAPK‐mediated production of IL‐1β, IL‐6 and IL‐8 by monocytes may be implicated as an explanation for the benefits shown for the host when resuscitation is performed under hypoxaemic conditions.

Nitrosative and Oxidative Stresses Contribute to Post-Ischemic Liver Injury Following Severe Hemorrhagic Shock: The Role of Hypoxemic Resuscitation

Purpose Hemorrhagic shock and resuscitation is frequently associated with liver ischemia-reperfusion injury. The aim of the study was to investigate whether hypoxemic resuscitation attenuates liver injury. Methods Anesthetized, mechanically ventilated New Zealand white rabbits were exsanguinated to a mean arterial pressure of 30 mmHg for 60 minutes. Resuscitation under normoxemia (Normox-Res group, n = 16, PaO2 = 95–105 mmHg) or hypoxemia (Hypox-Res group, n = 15, PaO2 = 35–40 mmHg) followed, modifying the FiO2. Animals not subjected to shock constituted the sham group (n = 11, PaO2 = 95–105 mmHg). Indices of the inflammatory, oxidative and nitrosative response were measured and histopathological and immunohistochemical studies of the liver were performed. Results Normox-Res group animals exhibited increased serum alanine aminotransferase, tumor necrosis factor - alpha, interleukin (IL) -1β and IL-6 levels compared with Hypox-Res and sham groups. Reactive oxygen species generation, malondialdehyde formation and myeloperoxidase activity were all elevated in Normox-Res rabbits compared with Hypox-Res and sham groups. Similarly, endothelial NO synthase and inducible NO synthase mRNA expression was up-regulated and nitrotyrosine immunostaining increased in animals resuscitated normoxemically, indicating a more intense nitrosative stress. Hypox-Res animals demonstrated a less prominent histopathologic injury which was similar to sham animals. Conclusions Hypoxemic resuscitation prevents liver reperfusion injury through attenuation of the inflammatory response and oxidative and nitrosative stresses.

Hypoxemic resuscitation after hemorrhagic shock is accompanied by reduced serum levels of angiopoietin-2.

BACKGROUND To investigate whether angiopoietin-2 (Ang2) and vascular endothelial growth factor (VEGF) are implicated in the hypoxemic resuscitation from hemorrhagic shock. METHODS Twenty rabbits were subjected to hemorrhagic shock after blood exsanguination; resuscitation was performed by infusion of the shed blood in ten rabbits under normoxemic conditions (NormoxRes) and in 10 under hypoxemic conditions (HypoxRes); four rabbits were subjected to sham operation. Serum was drawn at serial time intervals; serum was applied for stimulation of U937 monocytes. RESULTS Serum concentrations of Ang2 were higher in the NormoxRes group compared to the HypoxRes group at 90 min (p: 0.049) and at 120 min (p: 0.028). Serum concentrations of VEGF did not differ between groups. Concentrations of VEGF in the supernatants of U937 stimulated with sera of all groups were below detection limit. The wet to dry lung ratio of the HypoxRes group was significantly lower than the NormoxRes group (p<0.0001). CONCLUSIONS Hypoxemic resuscitation from hemorrhagic shock is a process accompanied by reduced serum levels of Ang2. These findings add significantly to our understanding of that experimental treatment strategy of resuscitation.