The response of the host microcirculation to bacterial sepsis: Does the pathogen matter?

Sepsis results from the interaction between a host and an invading pathogen. The microcirculatory dysfunction is now considered central in the development of the often deadly multiple organ dysfunction syndrome in septic shock patients. The microcirculatory flow shutdown and flow shunting leading to oxygen demand and supply mismatch at the cellular level and the local activation of inflammatory pathways resulting from the leukocyte-endothelium interactions are both features of the sepsis-induced microcirculatory dysfunction. Although the host response through the inflammatory and immunologic response appears to be critical, there are also evidences that Gram-positive and Gram-negative bacteria can exert different effects at the microcirculatory level. In this review we discuss available data on the potential bacterial-specific microcirculatory alterations observed during sepsis

MyD88 Dependent Signaling Contributes to Protective Host Defense against Burkholderia pseudomallei

Background: Toll-like receptors (TLRs) have a central role in the recognition of pathogens and the initiation of the innate immune response. Myeloid differentiation primary-response gene 88 (MyD88) and TIR-domain-containing adaptor protein inducing IFNb (TRIF) are regarded as the key signaling adaptor proteins for TLRs. Melioidosis, which is endemic in SE-Asia, is a severe infection caused by the gram-negative bacterium Burkholderia pseudomallei. We here aimed to characterize the role of MyD88 and TRIF in host defense against melioidosis. Methodology and Principal Findings: First, we found that MyD88, but not TRIF, deficient whole blood leukocytes released less TNFa upon stimulation with B. pseudomallei compared to wild-type (WT) cells. Thereafter we inoculated MyD88 knockout (KO), TRIF mutant and WT mice intranasally with B. pseudomallei and found that MyD88 KO, but not TRIF mutant mice demonstrated a strongly accelerated lethality, which was accompanied by significantly increased bacterial loads in lungs, liver and blood, and grossly enhanced liver damage compared to WT mice. The decreased bacterial clearance capacity of MyD88 KO mice was accompanied by a markedly reduced early pulmonary neutrophil recruitment and a diminished activation of neutrophils after infection with B. pseudomallei. MyD88 KO leukocytes displayed an unaltered capacity to phagocytose and kill B. pseudomallei in vitro. Conclusions: MyD88 dependent signaling, but not TRIF dependent signaling, contributes to a protective host respons

Year in review in Intensive Care Medicine 2010: I. Acute renal failure, outcome, risk assessment and ICU performance, sepsis, neuro intensive care and experimentals

SCOPUS: re.jinfo:eu-repo/semantics/publishe

The clinical frailty scale – does it predict outcome of the very-old in UK ICUs?

Introduction The age of patients admitted into critical care in the UK is increasing. Clinical decisions for very-old patients, usually defined as over 80, can be challenging. Clinicians are frequently asked to predict outcomes as part of discussions around the pros and cons of an intensive care unit (ICU) admission. Measures of overall health in old age, such as the clinical frailty scale (CFS), are increasingly used to help guide these discussions. We aimed to understand the characteristics of the very-old critically unwell population in the UK and the associations between frailty and outcome of an ICU admission in our healthcare system (National Health Service, NHS). Methods Baseline characteristics, ICU interventions and outcomes (ICU- and 30-day mortality) were recorded for sequential admissions of very old patients to UK ICUs as part of the European VIP 1 and 2 studies. Patient characteristics, interventions and outcome measures were compared by frailty group using standard statistical tests. Multivariable logistic regression modelling was undertaken to test association between baseline characteristics, admission type and outcome. Results 1858 participants were enrolled from 95 ICUs in the UK. The median age was 83. The median CFS was 4 (IQR 3–5). 30-day survival was significantly lower in the frail group (CFS > 4, 58%) compared to vulnerable (CFS = 4, 65%) and fit (CFS < 4 68%, p = .004). Sequential organ failure assessment (SOFA) score, reason for admission and CFS were all independently associated with increased 30-day mortality (p < .01). Conclusion In the UK, frailty is associated with an increase in mortality at 30-days following an ICU admission. At moderate frailty (CFS 5–6), three out of every five patients admitted survived to 30-days. This is a similar mortality to septic shock

30-Day Mortality among Very Old Patients Admitted to European Intensive Care Units for Major Trauma

Introduction: Cases of major trauma in the very old (over 80 years) are increasingly common in the intensive care unit (ICU). Predicting outcome is challenging in this group of patients as chronological age is a poor marker of health and poor predictor of outcome. Increasingly, decisions are guided by the use of organ dysfunction scores of both acute conditions (e.g., sequential organ failure assessment [SOFA] score) and chronic health issues (e.g., clinical frailty scale [CFS]). Recent work suggests that increased CFS is associated with a worse outcome in elderly major trauma patients. We aimed to test whether this association held true in the very old (over 80) or whether SOFA had a stronger association with 30-day outcome. Methods: Data from the very elderly intensive care patient (VIP)-1 and VIP-2 studies for patients over 80 years old with major trauma admissions were merged. These participants were recruited from 20 countries across Europe. Baseline characteristics, level of care provided, and outcome (ICU and 30-day mortality) were summarised. Uni- and multivariable regression analyses were undertaken to determine associations between CFS and SOFA score in the first 24 h, type of major trauma, and outcomes. Results: Of the 8,062 acute patients recruited to the two VIP studies, 498 patients were admitted to intensive care because of major trauma. Median age was 84 years, median SOFA score was 6 (IQR 3, 9), and median CFS was 3 (IQR 2, 5). Survival for 30 days was 54%. Median and interquartile range of CFS were the same for survivors and non-survivors. In the logistic regression analysis, CFS was not associated with increased mortality. SOFA score (p < 0.001) and trauma with head injury (p < 0.01) were associated with increased mortality. Conclusions: Major trauma admissions in the very old are not uncommon, and 30-day mortality is high. We found that CFS was not a helpful predictor of mortality. SOFA and trauma with head injury were associated with worse outcomes in this patient group

Modeling the structure of helical assemblies with experimental constraints in Rosetta

Determining high-resolution structures of proteins with helical symmetry can be challenging due to limitations in experimental data. In such instances, structure-based protein simulations driven by experimental data can provide a valuable approach for building models of helical assemblies. This chapter describes how the Rosetta macromolecular package can be used to model homomeric protein assemblies with helical symmetry in a range of modeling scenarios including energy refinement, symmetrical docking, comparative modeling, and de novo structure prediction. Data-guided structure modeling of helical assemblies with experimental information from electron density, X-ray fiber diffraction, solid-state NMR, and chemical cross-linking mass spectrometry is also described