Maria Auxiliadora-Martins

Interleukin-33 attenuates sepsis by enhancing neutrophil influx to the site of infection

Sepsis is a systemic inflammatory condition following bacterial infection with a high mortality rate and limited therapeutic options. Here we show that interleukin-33 (IL-33) reduces mortality in mice with experimental sepsis from cecal ligation and puncture (CLP). IL-33–treated mice developed increased neutrophil influx into the peritoneal cavity and more efficient bacterial clearance than untreated mice. IL-33 reduced the systemic but not the local proinflammatory response, and it did not induce a T helper type 1 (TH1) to TH2 shift. The chemokine receptor CXCR2 is crucial for recruitment of neutrophils from the circulation to the site of infection. Activation of Toll-like receptors (TLRs) in neutrophils downregulates CXCR2 expression and impairs neutrophil migration. We show here that IL-33 prevents the downregulation of CXCR2 and inhibition of chemotaxis induced by the activation of TLR4 in mouse and human neutrophils. Furthermore, we show that IL-33 reverses the TLR4-induced reduction of CXCR2 expression in neutrophils via the inhibition of expression of G protein–coupled receptor kinase-2 (GRK2), a serine-threonine protein kinase that induces internalization of chemokine receptors. Finally, we find that individuals who did not recover from sepsis had significantly more soluble ST2 (sST2, the decoy receptor of IL-33) than those who did recover. Together, our results indicate a previously undescribed mechanism of action of IL-33 and suggest a therapeutic potential of IL-33 in sepsis.

Essential Role of CCR2 in Neutrophil Tissue Infiltration and Multiple Organ Dysfunction in Sepsis

RATIONALE Sepsis is defined as a systemic inflammatory response to infection, which in its severe form is associated with multiple organ dysfunction syndrome (MODS). The precise mechanisms by which MODS develops remain unclear. Neutrophils have a pivotal role in the defense against infections; however, overwhelming activation of neutrophils is known to elicit tissue damage. OBJECTIVES We investigated the role of the chemokine receptor CCR2 in driving neutrophil infiltration and eliciting tissue damage in remote organs during sepsis. METHODS Sepsis was induced in wild-type mice treated with CCR2 antagonist (RS504393) or CCR2(-/-) mice by cecal ligation and puncture (CLP) model. Neutrophil infiltration into the organs was measured by myeloperoxidase activity and fluorescence-activated cell sorter. CCR2 expression and chemotaxis were determined in neutrophils stimulated with Toll-like receptor agonists or isolated from septic mice and patients. MEASUREMENTS AND MAIN RESULTS CCR2 expression and responsiveness to its ligands was induced in circulating neutrophils during CLP-induced sepsis by a mechanism dependent on Toll-like receptor/nuclear factor-κB pathway. Genetic or pharmacologic inhibition of CCR2 protected mice from CLP-induced mortality. This protection was associated with lower infiltration of neutrophils into the lungs, heart, and kidneys and reduced serum biochemical indicators of organ injury and dysfunction. Importantly, neutrophils from septic patients express high levels of CCR2, and the severity of patient illness correlated positively with increasing neutrophil chemotaxis to CCR2 ligands. CONCLUSIONS Collectively, these data identify CCR2 as a key receptor that drives the inappropriate infiltration of neutrophils into remote organs during sepsis. Therefore, CCR2 blockade is a novel potential therapeutic target for treatment of sepsis-induced MODS.

Effectiveness of Oral Rinse with Chlorhexidine in Preventing Nosocomial Respiratory Tract Infections among Intensive Care Unit Patients

OBJECTIVE To evaluate the effectiveness of the oral application of a 0.12% solution of chlorhexidine for prevention of respiratory tract infections among intensive care unit (ICU) patients. DESIGN The study design was a double-blind, randomized, placebo-controlled trial. SETTING The study was performed in an ICU in a tertiary care hospital at a public university. PATIENTS. Study participants comprised 194 patients admitted to the ICU with a prospective length of stay greater than 48 hours, randomized into 2 groups: those who received chlorhexidine (n = 98) and those who received a placebo (n = 96). INTERVENTION Oral rinses with chlorhexidine or a placebo were performed 3 times a day throughout the duration of the patients stay in the ICU. Clinical data were collected prospectively. RESULTS Both groups displayed similar baseline clinical features. The overall incidence of respiratory tract infections (RR, 1.0 [95% confidence interval [CI], 0.63-1.60]) and the rates of ventilator-associated pneumonia per 1,000 ventilator-days were similar in both experimental and control groups (22.6 vs 22.3; P = .95). Respiratory tract infection-free survival time (7.8 vs 6.9 days; P = .61), duration of mechanical ventilation (11.1 vs 11.0 days; P = .61), and length of stay (9.7 vs 10.4 days; P = .67) did not differ between the chlorhexidine and placebo groups. However, patients in the chlorhexidine group exhibited a larger interval between ICU admission and onset of the first respiratory tract infection (11.3 vs 7.6 days; P = .05). The chances of surviving the ICU stay were similar (RR, 1.08 [95% CI, 0.72-1.63]). CONCLUSION Oral application of a 0.12% solution of chlorhexidine does not prevent respiratory tract infections among ICU patients, although it may retard their onset.

Cytokine Signatures of Innate and Adaptive Immunity in 17DD Yellow Fever Vaccinated Children and Its Association With the Level of Neutralizing Antibody

BACKGROUND The live attenuated yellow fever (YF) vaccines have been available for decades and are considered highly effective and one of the safest vaccines worldwide. METHODS The impact of YF-17DD-antigens recall on cytokine profiles of YF-17DD-vaccinated children were characterized using short-term cultures of whole blood samples and single-cell flow cytometry. This study enrolled seroconverters and nonseroconverters after primovaccination (PV-PRNT⁺ and PV-PRNT⁻), seroconverters after revaccination (RV-PRNT⁺), and unvaccinated volunteers (UV-PRNT⁻). RESULTS The analysis demonstrated in the PV-PRNT⁺ group a balanced involvement of pro-inflammatory/regulatory adaptive immunity with a prominent participation of innate immunity pro-inflammatory events (IL-12⁺ and TNF-α⁺ NEU and MON). Using the PV-PRNT⁺ cytokine signature as a reference profile, PV-PRNT⁻ presented a striking lack of innate immunity proinflammatory response along with an increased adaptive regulatory profile (IL-4⁺CD4⁺ T cells and IL-10⁺ and IL-5⁺CD8⁺ T cells). Conversely, the RV-PRNT⁺ shifted the overall cytokine signatures toward an innate immunity pro-inflammatory profile and restored the adaptive regulatory response. CONCLUSIONS The data demonstrated that the overall cytokine signature was associated with the levels of PRNT antibodies with a balanced innate/adaptive immunity with proinflammatory/regulatory profile as the hallmark of PV-PRNT(MEDIUM⁺), whereas a polarized regulatory response was observed in PV-PRNT⁻ and a prominent proinflammatory signature was the characteristic of PV-PRNT(HIGH⁺).

Clinical and Immunological Insights on Severe, Adverse Neurotropic and Viscerotropic Disease following 17D Yellow Fever Vaccination

ABSTRACT Yellow fever (YF) vaccines (17D-204 and 17DD) are well tolerated and cause very low rates of severe adverse events (YEL-SAE), such as serious allergic reactions, neurotropic adverse diseases (YEL-AND), and viscerotropic diseases (YEL-AVD). Viral and host factors have been postulated to explain the basis of YEL-SAE. However, the mechanisms underlying the occurrence of YEL-SAE remain unknown. The present report provides a detailed immunological analysis of a 23-year-old female patient. The patient developed a suspected case of severe YEL-AVD with encephalitis, as well as with pancreatitis and myositis, following receipt of a 17D-204 YF vaccination. The patient exhibited a decreased level of expression of Fc-γR in monocytes (CD16, CD32, and CD64), along with increased levels of NK T cells (an increased CD3+ CD16+/− CD56+/−/CD3+ ratio), activated T cells (CD4+ and CD8+ cells), and B lymphocytes. Enhanced levels of plasmatic cytokines (interleukin-6 [IL-6], IL-17, IL-4, IL-5, and IL-10) as well as an exacerbated ex vivo intracytoplasmic cytokine pattern, mainly observed within NK cells (gamma interferon positive [IFN-γ+], tumor necrosis factor alpha positive [TNF-α+], and IL-4 positive [IL-4+]), CD8+ T cells (IL-4+ and IL-5+), and B lymphocytes (TNF-α+, IL-4+, and IL-10+). The analysis of CD4+ T cells revealed a complex profile that consisted of an increased frequency of IL-12+ and IFN-γ+ cells and a decreased percentage of TNF-α+, IL-4+, and IL-5+ cells. Depressed cytokine synthesis was observed in monocytes (TNF-α+) following the provision of antigenic stimuli in vitro. These results support the hypothesis that a strong adaptive response and abnormalities in the innate immune system may be involved in the establishment of YEL-AND and YEL-AVD.

Mechanical ventilation mode (volume × pressure) does not change the variables obtained by indirect calorimetry in critically ill patients ☆

PURPOSE The aim of the study was to analyze the difference between the results obtained by indirect calorimetry (IC) using volume-controlled and pressure-controlled mechanical ventilation in 2 different ventilators and to characterize the variables achieved by IC after well-defined changes in minute volume (Vm). MATERIALS AND METHODS Prospective study of 20 critically ill patients under volume-controlled (n = 15) or pressure-controlled (n = 5) mechanical ventilation. Three IC measurements of 45 minutes each were taken; values of oxygen consumption (Vo(2)), carbon dioxide production (Vco(2)), Vm, resting energy expenditure (REE), and respiratory quotient (RQ) were obtained. For the last measurement, Vm was set at 20% above the baseline. RESULTS There were no differences between the results obtained by IC during volume-controlled and pressure-controlled mechanical ventilation. The most relevant changes in the variables obtained by IC before and after intervention in Vm were a significant increase in Vco(2) (from 165 to 177 mL·min(-1); P < .01), a decrease in Paco(2) (from 38.49 to 28.46 mm Hg; P < .01), and a rise in pH (from 7.41 to 7.49; P < .01). There were no alterations in Vo(2), REE, or RQ. CONCLUSIONS Ventilators and ventilation modes do not influence the IC measurements. The observed changes have no clinical effects and are reversible, provided that increased Vm is maintained for no longer than 45 minutes.

Comparison of Acute Physiology and Chronic Health Evaluation II Death Risk, Child-Pugh, Charlson, and Model for End-stage Liver Disease Indexes to Predict Early Mortality After Liver Transplantation

OBJECTIVE This study sought to determine which prognostic index was the most efficient to predict early (1-month) mortality of patients undergoing orthotopic liver transplantation (OLT). MATERIALS AND METHODS This retrospective study included 63 patients including 49 males and 14 females of overall median age 51.6 ± 9.7 years who were admitted to the intensive care unit (ICU) of a tertiary hospital. The Acute Physiology and Chronic Health Evaluation II (APACHE II) death risk, Child-Pugh, Charlson, and Model for End-stage Liver Disease (MELD) indices pre-OLT and post-OLT were analyzed by generation of receiver operating characteristic (ROC) curves to determine the area under the ROC curve (AUC), as a predictive factor for each index. The level of significance was set at P < .05. RESULTS The general 1-month posttransplantation mortality rate of OLT patients was 19% (n = 12 p). The AUC was 0.81 (confidence interval [CI] = 0.66-0.96; sensitivity = 72.5; specificity = 83.3) for APACHE II death risk; 0.74 (CI = 0.57-0.92; sensitivity = 76.5; specificity = 66.7) for MELD post-OLT; 0.70 (CI = 0.54-0.85; sensitivity = 64.7; specificity = 66.7) for Child-Pugh; 0.57 (CI = 0.36-0.78; sensitivity = 74.5; specificity = 50.0) for Charlson; and 0.50 (CI = 0.32-0.69; sensitivity = 98.0; specificity = 16.7) for MELD Pre-OLT. CONCLUSION Among the studied indices, the APACHE II death risk scoring system was the most effective to predict early mortality after OLT.

17DD and 17D-213/77 yellow fever substrains trigger a balanced cytokine profile in primary vaccinated children.

Background This study aimed to compare the cytokine-mediated immune response in children submitted to primary vaccination with the YF-17D-213/77 or YF-17DD yellow fever (YF) substrains. Methods A non-probabilistic sample of eighty healthy primary vaccinated (PV) children was selected on the basis of their previously known humoral immune response to the YF vaccines. The selected children were categorized according to their YF-neutralizing antibody titers (PRNT) and referred to as seroconverters (PV-PRNT+) or nonseroconverters (PV-PRNT−). Following revaccination with the YF-17DD, the PV-PRNT− children (YF-17D-213/77 and YF-17DD groups) seroconverted and were referred as RV-PRNT+. The cytokine-mediated immune response was investigated after short-term in vitro cultures of whole blood samples. The results are expressed as frequency of high cytokine producers, taking the global median of the cytokine index (YF-Ag/control) as the cut-off. Results The YF-17D-213/77 and the YF-17DD substrains triggered a balanced overall inflammatory/regulatory cytokine pattern in PV-PRNT+, with a slight predominance of IL-12 in YF-17DD vaccinees and a modest prevalence of IL-10 in YF-17D-213/77. Prominent frequency of neutrophil-derived TNF-α and neutrophils and monocyte-producing IL-12 were the major features of PV-PRNT+ in the YF-17DD, whereas relevant inflammatory response, mediated by IL-12+CD8+ T cells, was the hallmark of the YF-17D-213/77 vaccinees. Both substrains were able to elicit particular but relevant inflammatory events, regardless of the anti-YF PRNT antibody levels. PV-PRNT− children belonging to the YF-17DD arm presented gaps in the inflammatory cytokine signature, especially in terms of the innate immunity, whereas in the YF-17D-213/77 arm the most relevant gap was the deficiency of IL-12-producing CD8+T cells. Revaccination with YF-17DD prompted a balanced cytokine profile in YF-17DD nonresponders and a robust inflammatory profile in YF-17D-213/77 nonresponders. Conclusion Our findings demonstrated that, just like the YF-17DD reference vaccine, the YF-17D-213/77 seed lot induced a mixed pattern of inflammatory and regulatory cytokines, supporting its universal use for immunization.

The use of perioperative serial blood lactate levels, the APACHE II and the postoperative MELD as predictors of early mortality after liver transplantation

PURPOSE To evaluate the accuracy of different parameters in predicting early (one-month) mortality of patients submitted to orthotopic liver transplantation (OLT). METHODS This is a retrospective study of forty-four patients (38 males and 10 females, mean age of 52.2 ± 8.9 years) admitted to the Intensive Care Unit of a tertiary hospital. Serial lactate blood levels, APACHE II, MELD post-OLT, creatinine, bilirubin and INR parameters were analyzed by receiver-operator characteristic (ROC) curves as evidenced by the area under the curve (AUC). The level of significance was set at 0.05. RESULTS The mortality of OLT patients within one month was 17.3%. Differences in blood lactate levels became statistically significant between survivors and nonsurvivors at the end of the surgery (p<0.05). The AUC was 0.726 (95%CI = 0.593-0.835) for APACHE II (p = 0.02); 0.770 (95%CI = 0.596-0.849) for blood lactate levels (L7-L8) (p = 0.03); 0.814 (95%CI = 0.690-0.904) for MELD post-OLT (p < 0.01); 0.550 (95%CI = 0.414-0.651) for creatinine (p = 0.64); 0.705 (95%CI = 0.571-0.818) for bilirubin (p = 0.05) and 0.774 (95%CI = 0.654-0.873) for INR (p = 0.02). CONCLUSION Among the studied parameters, MELD post-OLT was more effective in predicting early mortality after OLT.

Effectiveness of a Dental Care Intervention in the Prevention of Lower Respiratory Tract Nosocomial Infections among Intensive Care Patients: A Randomized Clinical Trial

OBJECTIVE To evaluate whether dental treatment may enhance oral antisepsis, thus preventing more effectively lower respiratory tract infections (LRTIs) among critically ill patients. DESIGN Observer-blind randomized clinical trial. SETTING General intensive care unit (ICU) for adult patients. PATIENTS We analyzed data from 254 adult patients who stayed for at least 48 hours in the ICU. INTERVENTION Patients were randomized by means of rolling dice. The experimental group (n = 127) had access to dental care provided by a dental surgeon, 4-5 times a week. Besides routine oral hygiene, care also included teeth brushing, tongue scraping, removal of calculus, atraumatic restorative treatment of caries, and tooth extraction. The control group (n = 127) had access to routine oral hygiene only, which included the use of chlorhexidine as a mouth rinse, which was performed by the ICU nurse staff. RESULTS The primary study outcome was the LRTI incidence, which was 8.7% in the experimental group and 18.1% in the control group (adjusted relative risk [RR], 0.44 [95% confidence interval (CI), 0.20-0.96]; P = .04). Ventilator-associated pneumonia rates per 1,000 ventilator-days were 16.5 (95% CI, 9.8-29.5) in the control group and 7.6 (95% CI, 3.3-15.0) in the experimental group (P < .05). Mortality rates were similar between both study groups: 31.5% in the control group versus 29.1% in the experimental group (adjusted RR, 0.93 [95% CI, 0.52-1.65]; P = .796). No severe adverse events related to oral care were observed during the study. CONCLUSION Dental treatment was safe and effective in the prevention of LRTI among critically ill patients who were expected to stay at least 48 hours in the ICU. TRIAL REGISTRATION Brazilian Clinical Trials Registry, affiliated with the World Health Organizations International Clinical Trial Registry Platform: U1111-1152-2671.