High-sensitive troponinT, interleukin-8, and interleukin-6 link with post-surgery risk in infant heart surgery.

BACKGROUND: This study focuses on biomarkers in infants after open heart surgery, and examines the association of high-sensitive troponin T (hs-cTnT), interleukin-6 (IL-6), and interleukin-8 (IL-8) with postoperative acute kidney injury (AKI), ventilatory support time and need of vasoactive drugs. METHODS: Secondary exploratory study from a double-blinded clinical randomized trial (Mile-1) on 70 infants undergoing open heart surgery with cardiopulmonary bypass (CPB). In this sub-study, the entire study population was examined without considering the study drugs. The biomarkers' peak concentration (highest concentration at 2 or 6 h post-CPB) were used for statistical analyses. RESULTS: Peak IL-8, hs-cTnT, and IL-6 occurred at 2 h post-CPB for 96%, 79%, and 63% of the patients, respectively. The odds ratio of developing AKI2-3 for IL-6 > 293 pg/mL was 23.4 (95% CI 5.3;104.0), for IL-8 > 100 pg/mL it was 11.5 (3.0;44.2), and for hs-cTnT >5597 pg/mL it was 6.1 (1.5; 24.5). In more than two third of the patients with the highest peak concentrations of IL-8, IL-6, and hs-cTnT, there was a need for ventilatory support for >24 h and use of vasoactive drugs at 24 h post-CPB, while in less than one third of the patients with the lowest peak concentrations of IL-8 and hs-cTnT such requirements were observed. CONCLUSIONS: The peak biomarker concentrations and CPB-time strongly predicted AKI2-3, with IL-6 and IL-8 emerging as strongest predictors. Furthermore, our findings suggest that measuring hs-cTnT and IL-8 just 2 h post-CPB-weaning may assist in identifying infants suitable for early extubation and highlight those at risk of prolonged ventilation.

Out-of-hospital cardiac arrest: Survival in children and young adults over 30 years, a nationwide registry-based cohort study.

OBJECTIVES: We studied short-term (30-day) and long-term (up to ten-year) survival among children and young adults following out-of-hospital cardiac arrest (OHCA) in Sweden over the course of the past 30 years. We also studied the causes of OHCA in children and examined predictors of survival. SETTING: This was a nationwide, registry-based cohort study, using the Swedish Registry of Cardiopulmonary Resuscitation. Our study comprised a cohort of 4,804 individuals aged 0 to 30 years who suffered OHCA between 1990 and 2020, in whom cardiopulmonary resuscitation (CPR) was initiated. We stratified the study cohort to distinct age groups and time periods. RESULTS: We found an increase in 30-day survival from 7% to 20% over the span of 30 years. In those under 1 year of age, survival increased from 2% to 19%. Time to CPR decreased from 14 to 2 min. The 10-year survival was high among those who survived 30 days. The etiology of cardiac arrests exhibited significant variations across different age groups but remained relatively consistent over time. Causes linked to mental illness constituted a substantial percentage of these cases. Compared to the reference period (1990-1994), the odds of survival in 2015-2020 was 3.00 (95% CI: 1.43, 6.94; p = 0.006). CONCLUSION: Survival rate after OHCA in children and young adults has increased three-fold over the past 30 years. Still overall mortality is high underscoring the need for continued efforts to mitigate risk factors and optimize survival.

Survival Trends in Children With Tetralogy of Fallot in Sweden From 1970 to 2017.

Importance: Mortality in patients with tetralogy of Fallot (TOF) has decreased substantially since the start of surgical correction of this abnormality in the 1950s. However, nationwide data in Sweden comparing survival trends among pediatric patients with TOF with the general population are still limited. Objective: To study survival trends in pediatric patients with TOF and compare them with matched controls. Design, Setting, and Participants: A Swedish registry-based, nationwide, matched cohort study was conducted; data were collected from national health registers from January 1, 1970, to December 31, 2017. Patients with a registered diagnosis of TOF as well as controls without TOF matched by birth year and sex were included in the study. Follow-up data were collected from birth to age 18 years, death, or the end of follow-up (December 31, 2017), whichever occurred first. Data analysis was performed from September 10 to December 20, 2022. Survival trends among patients with TOF were compared with matched controls using Cox proportional hazards regression and Kaplan-Meier survival analyses. Main Outcomes and Measures: All-cause mortality during childhood in patients with TOF and matched controls. Results: The population included 1848 patients (1064 [57.6%] males; mean [SD] age, 12.4 [6.7] years) with TOF and 16 354 matched controls. The number of patients who underwent congenital cardiac surgery (henceforth, surgery group) was 1527 (897 [58.7%] males). In the whole TOF population from birth until age 18 years, 286 patients (15.5%) died during a mean (SD) follow-up time of 12.4 (6.7) years. In the surgery group, 154 of 1527 patients (10.1%) died during a follow-up time of 13.6 (5.7) years with a mortality risk of 21.9 (95% CI, 16.2-29.7) compared with matched controls. When stratified by birth period, a substantial decrease in the mortality risk was noted in the surgery group, from 40.6 (95% CI, 21.9-75.4) in those born in the 1970s to 11.1 (95% CI, 3.4-36.4) in those born in the 2010s. Survival increased from 68.5% to 96.0%. The risk of mortality for surgery decreased from 0.52 in the 1979s to 0.19 in the 2010s. Conclusions and Relevance: The findings of this study suggest there has been substantial improvement in survival in children with TOF who underwent surgery from 1970 to 2017. However, the mortality rate is still significantly higher in this group compared with matched controls. Predictors of good and poor outcomes in this group need to be further explored, with the modifiable ones evaluated for further outcome improvements.

Outcome following anaesthesia in infancy in the Nordic countries: Subgroup analysis of the NECTARINE study.

INTRODUCTION: The neonate and children audit of anaesthesia practice in Europe (NECTARINE) prospective observational study reported an incidence of 35.2% of critical events requiring intervention during 6542 anaesthetics in 5609 infants up to 60 weeks postmenstrual age (PMA) from 165 centres in 31 European countries. METHODS: Sub-analysis of the cohort from the Nordic countries (8% of the entire cohort) was conducted. Secondary aims were to describe the Nordic countries' anaesthetic practices and compare morbidity and mortality with the overall European cohort. RESULTS: Eleven Nordic centres recruited 447 infants (66% males, 37.3% born preterm and 45% had congenital anomalies) undergoing anaesthesia for 530 surgical or non-surgical procedures at 25-60 weeks PMA. Perioperative critical events triggered interventions in 228/530 (43%) cases. Hypotension (12.6%) or hypoxaemia (11.7%) were more common in younger patients and those with co-morbidities. Hypo/hypercapnia occurred in 1.5%/4.7% of cases. More than two attempts for intubation were required in 13 (2.9%) infants (max three attempts). Distribution of ASA-Physical Status Scores was similar to the total European cohort (40% was ASA > 2). A total of 236/530 (44.5%) patients were admitted to the postoperative intensive care unit. Thirty-day morbidity (complications in 87/447 = 19.5%) and mortality (8/447, 1.8%) did not differ from the overall European cohort. Hospital re-admissions were significant up to 90 days (98/447 = 21.9%). CONCLUSIONS: In Nordic countries, anaesthesia in young infant children is resource-demanding, and perioperative critical events and co-morbidities are common. Thirty-day morbidity and mortality data in the Nordic countries did not differ from the overall European cohort.

Levosimendan Versus Milrinone and Release of Myocardial Biomarkers After Pediatric Cardiac Surgery: Post Hoc Analysis of Clinical Trial Data.

OBJECTIVES: We compared the effect of two inodilators, levosimendan and milrinone, on the plasma levels of myocardial injury biomarkers, that is, high-sensitivity troponin T and heart-type fatty acid binding protein, and on N-terminal prohormone of brain natriuretic peptide as a biomarker of ventricular function. We hypothesized that levosimendan could attenuate the degree of myocardial injury when compared with milrinone. DESIGN: A post hoc, nonprespecified exploratory secondary analysis of the Milrinone versus Levosimendan-1 trial (ClinicalTrials.gov Identifier: NCT02232399). SETTING: Two pediatric tertiary university hospitals. PATIENTS: Infants 1-12 months old, diagnosed with ventricular septal defect, complete atrioventricular septal defect, or Tetralogy of Fallot undergoing corrective surgery with cardiopulmonary bypass. INTERVENTIONS: Seventy patients received a loading dose of either levosimendan or milrinone at the start of cardiopulmonary bypass followed by an infusion of the respective drug, which continued for 26 hours. MEASUREMENTS AND MAIN RESULTS: Plasma levels of the three cardiac biomarkers were measured prior to the initiation of cardiopulmonary bypass and 2, 6, and 24 hours after weaning from cardiopulmonary bypass. In both groups, the levels of high-sensitivity troponin T and heart-type fatty acid binding protein were highest at 2 hours post cardiopulmonary bypass, whereas the highest level of N-terminal prohormone of brain natriuretic peptide occurred at 24 hours post cardiopulmonary bypass. There was no significant difference in the biomarkers' plasma levels between the study groups over time. Neither was there a significant difference in the postoperative peak plasma levels of the cardiac biomarkers. CONCLUSIONS: In this post hoc analysis of the MiLe-1 trial, there was no demonstrable difference in the postoperative cardiac biomarker profile of myocardial injury and ventricular function when comparing infants managed in the perioperative period with levosimendan versus milrinone.

Levosimendan Versus Milrinone for Inotropic Support in Pediatric Cardiac Surgery: Results From a Randomized Trial.

OBJECTIVE: The present study aimed to determine the differential effects of intraoperative administration of milrinone versus levosimendan on myocardial function after pediatric cardiac surgery. Transthoracic echocardiography was used for myocardial function evaluation using biventricular longitudinal strain with 2-dimensional speckle tracking echocardiography in addition to conventional echocardiographic variables. DESIGN: A secondary analysis of a randomized, prospective, double-blinded clinical drug trial. SETTING: Two pediatric tertiary university hospitals. PARTICIPANTS: Infants between 1 and 12 months old diagnosed with ventricular septal defect, complete atrioventricular septal defect, or tetralogy of Fallot who were scheduled for corrective surgery with cardiopulmonary bypass. INTERVENTIONS: The patients were randomly assigned to receive an infusion of milrinone or levosimendan at the start of cardiopulmonary bypass and for 26 consecutive hours. MEASUREMENTS AND MAIN RESULTS: Biventricular longitudinal strain and conventional echocardiographic variables were measured preoperatively, on the first postoperative morning, and before hospital discharge. The association between perioperative parameters and postoperative myocardial function also was investigated. Images were analyzed for left ventricular (n = 67) and right ventricular (n = 44) function. The day after surgery, left ventricular longitudinal strain deteriorated in both the milrinone and levosimendan groups (33% and 39%, respectively). The difference was not significant. The corresponding deterioration in right ventricular longitudinal strain was 42% and 50% (nonsignificant difference). For both groups, biventricular longitudinal strain approached preoperative values at hospital discharge. Preoperative N-terminal pro-brain natriuretic peptide could predict the left ventricular strain on postoperative day 1 (p = 0.014). CONCLUSIONS: Levosimendan was comparable with milrinone for left and right ventricular inotropic support in pediatric cardiac surgery.

The Effect of Levosimendan Versus Milrinone on the Occurrence Rate of Acute Kidney Injury Following Congenital Heart Surgery in Infants: A Randomized Clinical Trial.

OBJECTIVES: It has been shown that, in contrast to other inotropic agents, levosimendan improves glomerular filtration rate after adult cardiac surgery. The aim of this study was to investigate the efficacy of levosimendan, compared with milrinone, in preventing acute kidney dysfunction in infants after open-heart surgery with cardiopulmonary bypass. DESIGN: Two-center, double-blinded, prospective, randomized clinical trial. SETTING: The study was performed in two tertiary pediatric centers, one in Sweden (Gothenburg) and one in Finland (Helsinki). PATIENTS: Infants between 1 and 12 months old, diagnosed with Tetralogy of Fallot, complete atrioventricular septal defect or nonrestrictive ventricular septal defect, undergoing total corrective cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: Seventy-two infants were randomized to receive a perioperative infusion of levosimendan (0.1 µg/kg/min) or milrinone (0.4 µg/kg/min). The infusion was initiated at the start of cardiopulmonary bypass and continued for 26 hours. MEASUREMENTS AND MAIN RESULTS: The primary outcome variable was the absolute value of serum creatinine data on postoperative day 1. Secondary outcomes included the following: 1) acute kidney injury according to the serum creatinine criteria of the Kidney Diseases: Improving Global Outcomes; 2) acute kidney injury with serum creatinine corrected for fluid balance; 3) plasma neutrophil gelatinase-associated lipocalin; 4) cystatin C; 5) urea; 6) lactate; 7) hemodynamic variables; 8) use of diuretics in the PICU; 9) need of dialysis; 10) length of ventilator therapy; and 11) length of PICU stays. There was no significant difference in postoperative serum creatinine between the treatment groups over time (p = 0.65). The occurrence rate of acute kidney injury within 48 hours was 46.9% in the levosimendan group and 39.5% in the milrinone group (p = 0.70). There were no significant differences in other secondary outcome variables between the groups. CONCLUSIONS: Levosimendan compared with milrinone did not reduce the occurrence rate of acute kidney injury in infants after total corrective heart surgery for atrioventricular septal defect, ventricular septal defect, or Tetralogy of Fallot.

Incidence of severe critical events in paediatric anaesthesia in Scandinavia: Secondary analysis of Anaesthesia PRactice In Children Observational Trial (APRICOT).

BACKGROUND: The Anaesthesia PRactice In Children Observational Trial (APRICOT) in 261 European hospitals revealed a 5.2% incidence of severe critical events in the perioperative period and wide variability in practice. METHODS: A sub-analysis of the Scandinavian data was undertaken to investigate differences from the rest of Europe in the incidence and nature of perioperative severe critical events and to attempt to identify areas for quality improvement. FINDINGS: In the Scandinavian cohorts of 1520 paediatric patients out of 31 127 patients, the overall incidence of perioperative severe critical events was lower than the rest of Europe (4.4% (95% CI [3.5-5.6]) vs 5.2% (95% CI [5.0-5.5]); RR 0.57), albeit the incidence varied across countries. There was a lower rate of bronchospasm (0.9%), stridor (1.1%) and cardiovascular instability (0.9%) than the rest of Europe. The proportion of bronchospasm events occurring at induction was 0.13% in Scandinavian cohort which was less than the rest of Europe (1.2%). The proportion of sicker patients where less experienced teams were managing the care was notably lower in Scandinavia than in the rest of Europe (14.4% vs 20.4% of the American Society of Anesthesiologists Physical Status Classification System Score (ASA-PS III and 8.3% vs 12.8% of the ASA-PS IV. Cardiovascular instability was lower in Scandinavia (0.92%) compared to Europe (1.9%). The incidence of drug errors was low in both the overall APRICOT (0.2%) and in Scandinavia (0.3%). There were no deaths. INTERPRETATION: This sub-analysis shows that current Scandinavia paediatric perioperative clinical practice compares favourably with the rest of Europe. The lower incidence of cardiovascular and respiratory complications could be partly attributed to more experienced dedicated paediatric anaesthesia providers managing the higher risk groups of patients in Scandinavia. Whether this cohort of anaesthetized children is truly representative of the entire Scandinavia countries is unknown. Areas for quality improvement include: standardisation of the definition of severe critical events, increased reporting, development of evidence-based protocols for the management of severe critical events, development and rational implementation of paediatric perioperative risk assessment scores, implementation of current best practice in the provision of competent paediatric anaesthesia service in Europe, development of specific training and ensuring maintenance skills in paediatric anaesthesia. Furthermore, based on data from the original Apricot paper children under the age of 3 years and ASA-PS III and IV patients should not be anaesthetised without direct supervision of a specialist in paediatric anaesthesia. Given the sample size of the Scandinavian cohort this conclusion cannot be investigated further.

Exploration of 27 plasma immune markers: a cross-sectional comparison of 64 old psychiatric inpatients having unipolar major depression and 18 non-depressed old persons.

BACKGROUND: The prevalence of major depression (MD) according to population studies is the same for old (65 years and older) and younger adults. In contrast, an elevated proportion of old MD patients are hospitalized compared to younger adults with MD, indicating a need to expand the characteristics of old inpatients with MD. To illustrate this point, the association between inflammation and MD in old psychiatric inpatients is sparsely investigated even though an association between inflammation and treatment resistance among younger adults with MD has been reported. In this study, we aimed to explore the plasma concentrations of 27 immune markers in old inpatients with MD, and our purpose was to expand the understanding of inflammatory mechanisms in these patients. METHODS: Prior to electroconvulsive treatment of MD, we compared 64 inpatients with unipolar MD (mean age 75.2 years) and 18 non-depressed controls (mean age 78.0 years). Symptoms characterizing MD were assessed by the Hamilton Rating Scale of Depression (HRSD)-17, and the immune markers from peripheral blood plasma were analysed using multiplex assay technology. For statistical analysis of data, we used the independent samples median test, independent samples t-test, χ2-test, receiver operating characteristic curve analyses, stepwise discriminant analysis, and multivariate linear regression. RESULTS: Twenty-two immune markers representing pro- and anti-inflammatory, adaptive and trophic signalling had higher concentrations in the inpatients compared to the controls. Only the four immune markers IL-1ß, IL-5, IL-10 and IL-15 had concentrations below the lower detection limit in a considerable portion (above 20%) of the patient cases. A combination of the concentration in plasma of TNF, vascular endothelial growth factor (VEGF), IL-1ß, IL-7 and monocyte chemotactic protein (MCP)-1, correctly classified 98.4% of the depressed patients and 83.3% of the non-depressed controls. Plasma concentration of TNF and VEGF were associated with the HRSD-17 scores (p = 0.017 and 0.005, respectively). CONCLUSIONS: Our results indicate that several inflammatory mechanisms may be highly activated in old psychiatric inpatients with MD, and indicate that immune markers may contribute to a more comprehensive understanding of MD in old persons. TRIAL REGISTRATION: NCT01559324 ClinicalTrials.gov.

Combined Inhibition of C5 and CD14 Attenuates Systemic Inflammation in a Piglet Model of Meconium Aspiration Syndrome.

BACKGROUND: Meconium aspiration syndrome (MAS) is a severe lung condition affecting newborns and it can lead to a systemic inflammatory response. We previously documented complement activation and cytokine release in a piglet MAS model. Additionally, we showed ex vivo that meconium-induced inflammation was dependent on complement and Toll-like receptors. OBJECTIVES: To assess the efficacy of the combined inhibition of complement (C5) and CD14 on systemic inflammation induced in a forceful piglet MAS model. METHODS: Thirty piglets were randomly allocated to a treatment group receiving the C5-inhibitor SOBI002 and anti-CD14 (n = 15) and a nontreated control group (n = 15). MAS was induced by intratracheal meconium instillation, and the piglets were observed for 5 h. Complement, cytokines, and myeloperoxidase (MPO) were measured by ELISA. RESULTS: SOBI002 ablated C5 activity and the formation of the terminal complement complex in vivo. The combined inhibition attenuated the inflammasome cytokines IL-1ß and IL-6 by 60 (p = 0.029) and 44% (p = 0.01), respectively, and also MPO activity in the bronchoalveolar fluid by 42% (p = 0.017). Ex vivo experiments in human blood revealed that the combined regimen attenuated meconium-induced MPO release by 64% (p = 0.008), but there was only a negligible effect with single inhibition, indicating a synergic cross-talk between the key molecules C5 and CD14. CONCLUSION: Combined inhibition of C5 and CD14 attenuates meconium-induced inflammation in vivo and this could become a future therapeutic regimen for MAS.

The role of general anesthesia on traits of neurodevelopmental disorders in a Swedish cohort of twins.

BACKGROUND: The role of general anesthetics as a risk factor for possible neurodevelopmental disorders (NDDs) in humans is unresolved. The investigation of the role of anesthetics in the development of postgeneral anesthesia (anesthesia onward) NDDs has proven to be complicated, partly because of the inherent confounding in clinical cohort studies, and partly by the fact that anesthetics are only one part in the complex process of anesthesia-surgery. METHODS: Utilizing the Swedish databases Child and Adolescent Twins Study in Sweden (CATSS) and National Patient Register (NPR), we investigated twins discordant for anesthesia, born between 1997 and 2004 for traits of NDDs. We identified 68 twin pairs discordant for anesthesia and explored traits of Attention-Deficit/Hyperactivity Disorder (ADHD), Learning Disability (LD), and Autism Spectrum Disorder (ASD) in them while simultaneously taking congenital abnormalities and systemic disorders (CSDs) into account. We analyzed the possible effect of anesthesia on neurodevelopmental problems, and we analyzed the within-pair differences using conditional linear regression. RESULTS: Twins with a recorded episode of anesthesia had higher traits of NDDs than twins without; similarly twins with CSDs had higher mean scores on all traits than twins without CSDs. The within-pair analyses suggested that exposure to anesthesia was associated with higher scores of ADHD (regression coefficient 1.02 and 95% confidence intervals: 0.27-1.78) in monozygotic (MZ) twins discordant for anesthesia. This effect remained when adjusting for congenital abnormalities. DISCUSSION: Our finding that traits of ADHD were slightly associated with anesthesia in a genetically sensitive design is in need of replication and warrants further investigation. Future studies should aim to elucidate mechanisms behind this possible association (e.g. anesthetics doses, age at exposure, exposure duration).

Combined inhibition of C5 and CD14 efficiently attenuated the inflammatory response in a porcine model of meningococcal sepsis.

BACKGROUND: Fulminant meningococcal sepsis, characterized by overwhelming innate immune activation, mostly affects young people and causes high mortality. This study aimed to investigate the effect of targeting two key molecules of innate immunity, complement component C5, and co-receptor CD14 in the Toll-like receptor system, on the inflammatory response in meningococcal sepsis. METHODS: Meningococcal sepsis was simulated by continuous intravenous infusion of an escalating dose of heat-inactivated Neisseria meningitidis administered over 3 h. The piglets were randomized, blinded to the investigators, to a positive control group (n = 12) receiving saline and to an interventional group (n = 12) receiving a recombinant anti-CD14 monoclonal antibody together with the C5 inhibitor coversin. RESULTS: A substantial increase in plasma complement activation in the untreated group was completely abolished in the treatment group (p = 0.006). The following inflammatory mediators were substantially reduced in plasma in the treatment group: Interferon-γ by 75% (p = 0.0001), tumor necrosis factor by 50% (p = 0.01), Interleukin (IL)-8 by 50% (p = 0.03), IL-10 by 40% (p = 0.04), IL-12p40 by 50% (p = 0.03), and granulocyte CD11b (CR3) expression by 20% (p = 0.01). CONCLUSION: Inhibition of C5 and CD14 may be beneficial in attenuating the detrimental effects of complement activation and modulating the cytokine storm in patients with fulminant meningococcal sepsis.

In vitro anti-platelet potency of ticagrelor in blood samples from infants and children.

INTRODUCTION: Ticagrelor, a novel platelet inhibitor acting on the ADP-dependent P2Y12 receptor, is currently approved for treating adults with acute coronary syndrome. The effect of ticagrelor in children has not been explored. As a first step, we here evaluate if the in vitro anti-platelet potency of ticagrelor in blood samples from children of different age is different as compared with in blood samples from adults. MATERIALS AND METHODS: Blood samples from 36 healthy children grouped by age (0-2 months, n=6; 2-6 months, n=6; 6months-2years, n=6; 2-6 years, n=10; 6-12 years, n=8) and 13 adults were collected for in vitro analysis using vasodilator stimulated phosphoprotein phosphorylation (VASP) assay in whole blood and ADP-induced light transmission aggregometry (LTA) in platelet rich plasma. Ticagrelor (0.01 - 10µmol/L) was added in vitro and its potency was assessed by calculating the concentration that provided 50% inhibition of the maximum response (IC50). RESULTS: The in vitro potency of ticagrelor in blood from adults and in blood from children of any age group were comparable, both when analyzed with LTA and with VASP. CONCLUSIONS: These in vitro results are consistent with the hypothesis that ticagrelor would achieve a comparable anti-platelet effect in children of different ages as in adults at equal plasma exposure.

Meconium aspiration syndrome: possible pathophysiological mechanisms and future potential therapies.

Does meconium cause meconium aspiration syndrome (MAS) or is meconium discharge only a marker of fetal hypoxia? This dispute has lasted for centuries, but since the 1960s, detrimental effects of meconium itself on the lungs have been demonstrated in animal experiments. In clinical MAS, persistent pulmonary hypertension of the newborn is the leading cause of death in MAS. Regarding the complex chemical composition of meconium, it is difficult to identify a single agent responsible for the pathophysiology. However, considering that meconium is stored in the intestines, partly unexposed to the immune system, aspirated meconium could be recognized as 'danger', representing damaged self. The common denominator in the pathophysiology could therefore be activation of innate immunity. Thus, a bulk of evidence implies that meconium is a potent activator of inflammatory mediators, including cytokines, complement, prostaglandins and reactive oxygen species. We hypothesize that the two main recognition systems of innate immunity, the Toll-like receptors and the complement system, recognize meconium as 'danger', which leads not only to lung dysfunction but also to a systemic inflammatory response. This might have therapeutic implications in the future.

Polyvalent immunoglobulin significantly attenuated the formation of IL-1ß in Escherichia coli-induced sepsis in pigs.

Evidence suggests that adjunctive treatment with intravenous immunoglobulin preparations enriched with IgA and IgM reduce mortality in sepsis. The mode of action of polyvalent immunoglobulin is complex, including neutralization of toxins and modulation of complement activation and cytokine formation toward an anti-inflammatory profile. In this study we explored the effect of Pentaglobin, containing IgG, IgA and IgM, on the initial inflammatory reaction as well as on hemodynamics, using a well characterized and standardized porcine model of sepsis. Anesthetized and mechanically ventilated pigs, mean weight 14.9 kg, were allocated into two groups of 8 animals, receiving either Pentaglobin or saline, before sepsis was induced by intravenous Escherichia coli infusion. Five negative controls received saline only. All animals were observed for 4 h under extensive invasive monitoring. Pentaglobin significantly (p < 0.05) attenuated IL-1ß formation by 38% at the end of the experiment, and markedly increased (p < 0.05) the formation of IL-10 at 60 min. TNF-α, IL-6, IL-8 and expression of the cell surface marker wCD11R3 were lower in the Pentaglobin group, but the differences were not significant. The serum concentration of LPS was three times higher in the Pentaglobin group (p < 0.005), indicating binding of LPS to Pentaglobin. Complementary in vitro experiments showed a higher binding affinity for IgM and IgA to LPS than for IgG. LPS-induced formation of IL-6 was significantly (p < 0.05) attenuated by Pentaglobin in an in vitro whole blood model. In conclusion, Pentaglobin decreased the key inflammasome IL-1ß molecule in an E. coli-model of pigs sepsis.

Hyperoxic resuscitation after hypoxia-ischemia induces cerebral inflammation that is attenuated by tempol in a reporter mouse model with very young mice.

BACKGROUND: Oxygen supplementation is still part of international resuscitation protocols for premature children. Mechanisms for tissue damage by hypoxia/ischemia in the extreme premature involve inflammation. AIM AND METHOD: To study cerebral inflammation after hypoxia/ischemia and oxygen treatment in the premature, we measured NF-κB activity in 5-day-old transgenic reporter mice in response to experimental hypoxia/ischemia. results were correlated to cerebral histological evaluation and plasma cytokine levels. A treatment strategy with the antioxidant tempol was tested. RESULTS: One day after hypoxia/ischemia NF-κB activation was increased compared to controls [mean difference: 10.6±4.6% (P=0.03)]. Exposure to 100% oxygen after hypoxia/ischemia further increased NF-κB activation compared to hypoxia/ischemia alone [mean difference: 15.0±5.5% (P=0.01)]. Histological changes in the brain were positively correlated with NF-κB activity (P<0.001), but we found no significant difference in tissue damage between resuscitation with air and resuscitation with pure oxygen. Administration of tempol reduced NF-κB activation [mean difference: 14.6±5.0% (P=0.01)] and the plasma level of cytokines; however, the histological damage score was not affected. CONCLUSION: Cerebral inflammatory response after hypoxia/ischemia in a mouse model with immature brain development corresponding to human prematurity prior to 32 weeks' gestation was influenced by administration of oxygen. Tempol treatment attenuated inflammation but did not reduce the extent of histological cerebral damage.

The role of bradykinin and the effect of the bradykinin receptor antagonist icatibant in porcine sepsis.

Bradykinin (BK) is regarded as an important mediator of edema, shock, and inflammation during sepsis. In this study, we evaluated the contribution of BK in porcine sepsis by blocking BK and by measuring the stable BK metabolite, BK1-5, using anesthetized pigs. The effect of BK alone, the efficacy of icatibant to block this effect, and the recovery of BK measured as plasma BK1-5 were first investigated. Purified BK injected intravenously induced an abrupt fall in blood pressure, which was completely prevented by pretreatment with icatibant. BK1-5 was detected in plasma corresponding to the doses given. The effect of icatibant was then investigated in an established model of porcine gram-negative sepsis. Neisseria meningitidis was infused intravenously without any pretreatment (n = 8) or pretreated with icatibant (n = 8). Negative controls received saline only. Icatibant-treated pigs developed the same degree of severe sepsis as did the controls. Both groups had massive capillary leakage, leukopenia, and excessive cytokine release. The plasma level of BK1-5 was low or nondetectable in all pigs. The latter observation was confirmed in supplementary studies with pigs undergoing Escherichia coli or polymicrobial sepsis induced by cecal ligation and puncture. In conclusion, icatibant completely blocked the hemodynamic effects of BK but had no beneficial effects on N. meningitidis-induced edema, shock, and inflammation. This and the fact that plasma BK1-5 in all the septic pigs was virtually nondetectable question the role of BK as an important mediator of porcine sepsis. Thus, the data challenge the current view of the role of BK also in human sepsis.

Neisseria meningitidis and Escherichia coli are protected from leukocyte phagocytosis by binding to erythrocyte complement receptor 1 in human blood.

The initial interaction of Gram-negative bacteria with erythrocytes and its implications on leukocyte phagocytosis and oxidative burst in human whole blood were examined. Alexa-labeled Escherichia coli, wild-type H44/76 N. meningitidis and the H44/76lpxA lipopolysaccharide (LPS)-deficient mutant were incubated with whole blood using lepirudin as anticoagulant which has no adverse effects on complement. Bacteria free in plasma, bound to erythrocytes or phagocytized by granulocytes and monocytes were quantified using flow cytometry. The effects of the C3 inhibitor compstatin, a C5a receptor antagonist (C5aRa) and a complement receptor 1 (CR1)-blocking antibody (3D9) were examined. Most bacteria (80%) immediately bound to erythrocytes. The binding gradually declined over time, with a parallel increase in phagocytosis. Complement inhibition with compstatin reduced erythrocyte binding and bacterial C3 opsonization. In contrast, the C5aRa efficiently reduced phagocytosis, but did not affect the binding of bacteria to erythrocytes. The anti-CR1 blocking mAb dose-dependently reduced bacterial binding to erythrocytes to nil, with subsequent increased phagocytosis and oxidative burst. LPS had no effect on these processes since similar results were obtained using an LPS-deficient N. meningitidis mutant. In vivo experiments in a pig model of sepsis showed limited binding of bacteria to erythrocytes, consistent with the facts that erythrocyte CR1 receptors are absent in non-primates and that the bacteria were mainly found in the lungs. In conclusion, complement-dependent binding of Gram-negative bacteria to erythrocyte CR1 decreases phagocytosis and oxidative burst by leukocytes in human whole blood.

Dissecting the effects of lipopolysaccharides from nonlipopolysaccharide molecules in experimental porcine meningococcal sepsis.

OBJECTIVE: To dissect the in vivo responses to lipopolysaccharide compared with nonlipopolysaccharide structures of whole meningococci. DESIGN: Comparative experimental study. SETTING: University hospital with an animal intensive care unit and laboratory. SUBJECTS: Twenty-four anesthetized healthy Norwegian landrace pigs of 30 kg (+/- 2.5 kg) grouped into two test groups and one control group. INTERVENTIONS: Exponentially increasing numbers of Neisseria meningitidis H44/76 (NmLPS+) or a knockout mutant of H44/76 completely lacking lipopolysaccharide (NmLPS-) were infused intravenously to the pigs. MEASUREMENTS AND MAIN RESULTS: Physiological and hematologic parameters were continuously recorded and biochemical analyses were performed in batch after completion. Systemic vascular resistance, cardiac index and lactate changed significantly more in the NmLPS+ than in the NmLPS- group (p < .05). Mean pulmonary artery pressure increased early in the NmLPS+ and late in the NmLPS- group, but finally reached equally high values. Capillary leakage (fluid requirement, plasma albumin loss, organ wet/dry ratio) was more prominent in the NmLPS+ group (p < .05). Leukocytes were depleted in a highly lipopolysaccharide-dependent manner (p < .001). Thrombin-antithrombin complexes and plasminogen activator inhibitor-1 increased 2.5 to five times more in the NmLPS+ group (p < .05). Maximum cytokine concentrations in plasma were markedly higher in the NmLPS+ group (p < .05): tumor necrosis factor-alpha (40 times), interleukin-1beta (40 times), interleukin-6 (13 times), and interleukin-10 (four times). Interleukin-12 increased only in the NmLPS+ group. CONCLUSION: This large animal model, which simulates human disease well, confirms the potency of lipopolysaccharide but provides clear evidence that nonlipopolysaccharide molecules induce cardiovascular and hematologic changes quite similar to those caused by lipopolysaccharide. In general, 10- to 20-fold higher doses of the lipopolysaccharide-deficient mutant were required to induce the same degree of pathophysiological changes. Endotoxic activity of Gram-negative bacteria should no longer be attributed solely to the activity of lipopolysaccharide.