Reduced Proprotein convertase subtilisin/kexin 9 (PCSK9) function increases lipoteichoic acid clearance and improves outcomes in Gram positive septic shock patients.

Previous studies have shown lipopolysaccharide from Gram-negative bacteria is cleared from the circulation via LDL receptors on hepatocytes, which are downregulated by PCSK9. Whether clearance of Gram positive bacterial lipoteichoic acid (LTA) shows similar dependence on PCSK9, and whether this is clinically relevant in Gram positive human sepsis, is unknown. We examined survival data from three cohorts of patients who had Gram positive septic shock (n = 170, n = 130, and n = 59) and found that patients who carried a PCSK9 loss-of-function (LOF) allele had significantly higher 28-day survival (73.8%) than those with no LOF alleles (52.8%) (p = 0.000038). Plasma clearance of LTA was also found to be increased in PCSK9 knockout mice compared to wildtype control mice (p = 0.002). In addition, hepatocytes pre-treated with recombinant wildtype PCSK9 showed a dose-dependent decrease in uptake of fluorescently-labeled LTA (p < 0.01). In comparison to wildtype PCSK9, hepatocytes pre-treated with 3 different LOF variants of recombinant PCSK9 showed an increase in LTA uptake. This study shows the clearance of LTA follows a similar route as lipopolysaccharide, which is dependent on hepatic LDL receptors. This has important implications in health as strategies aimed at inhibiting PCSK9 function may be an effective treatment option for both Gram-positive and negative sepsis.

CETP genetic variant rs1800777 (allele A) is associated with abnormally low HDL-C levels and increased risk of AKI during sepsis.

High-density cholesterol (HDL-C) levels are influenced by genetic variation in several genes. Low levels of HDL-C have been associated with increased risk of acute kidney injury (AKI). We investigated whether genetic polymorphisms in ten genes known to regulate HDL-C levels are associated with both HDL-C levels and AKI development during sepsis. Two cohorts were retrospectively analyzed: Derivation Cohort (202 patients with sepsis enrolled at the Emergency Department from 2011 to 2014 in Vancouver, Canada); Validation Cohort (604 septic shock patients enrolled into the Vasopressin in Septic Shock Trial (VASST)). Associations between HDL-related genetic polymorphisms and both HDL-C levels, and risk for clinically significant sepsis-associated AKI (AKI KDIGO stages 2 and 3) were evaluated. In the Derivation Cohort, one genetic variant in the Cholesteryl Ester Transfer Protein (CETP) gene, rs1800777 (allele A), was strongly associated with lower HDL-C levels (17.4 mg/dL vs. 32.9 mg/dL, P = 0.002), greater CETP mass (3.43 µg/mL vs. 1.32 µg/mL, P = 0.034), and increased risk of clinically significant sepsis-associated AKI (OR: 8.28, p = 0.013). Moreover, the same allele was a predictor of sepsis-associated AKI in the Validation Cohort (OR: 2.38, p = 0.020). Our findings suggest that CETP modulates HDL-C levels in sepsis. CETP genotype may identify patients at high-risk of sepsis-associated AKI.

Impact of PCSK9 loss-of-function genotype on 1-year mortality and recurrent infection in sepsis survivors.

BACKGROUND: Reduced activity of proprotein convertase subtilisin/kexin type 9 (PCSK9) has been associated with decreased short-term death in patients with septic shock. Whether PCSK9 genotype influences long-term outcomes in sepsis survivors is unknown. METHODS: We evaluated the impact of PCSK9 loss-of-function (LOF) genotype on both 1-year mortality and infection-related readmission (IRR) after an index sepsis admission. The Derivation cohort included 342 patients who survived 28 days after a sepsis admission in a tertiary hospital (Vancouver/Canada, 2004-2014), while an independent Validation cohort included 1079 septic shock patients admitted at the same hospital (2000-2006). All patients were genotyped for three common missense PCSK9 LOF variants rs11591147, rs11583680, rs562556 and were classified in 3 groups: Wildtype, single PCSK9 LOF, and multiple PCSK9 LOF, according to the number of LOF alleles per patient. We also performed a meta-analysis using both cohorts to investigate the effects of PCSK9 genotype on 90-day survival. FINDINGS: In the Derivation cohort, patients carrying multiple PCSK9 LOF alleles showed lower risk for the composite outcome 1-year death or IRR (HR: 0.40, P = 0.006), accelerated reduction on neutrophil counts (P = 0.010), and decreased levels of PCSK9 (P = 0.037) compared with WT/single LOF groups. Our meta-analysis revealed that the presence of multiple LOF alleles was associated with lower 90-day mortality risk (OR = 0.69, P = 0.020). INTERPRETATION: The presence of multiple PCSK9 LOF alleles decreased the risk of 1-year death or IRR in sepsis survivors. Biological measures suggest this may be related to an enhanced resolution of the initial infection. FUNDING: Canadian Institutes of Health Research (PJT-156056).

The Understanding and Management of Organism Toxicity in Septic Shock.

The toxicity caused by different organisms in septic shock is substantially complex and characterized by an intricate pathogenicity that involves several systems and pathways. Immune cells' pattern recognition receptors initiate the host response to pathogens after the recognition of pathogen-associated molecular patterns. In essence, the subsequent activation of downstream pathways may progress to infection resolution or to a dysregulated host response that represents the hallmark of organ injury in septic shock. Likewise, the management of organism toxicity in septic shock is complicated and comprises a multiplicity of suitable targets. In this review, the classic immune responses to pathogens are discussed as well as other factors that are relevant in the pathogenicity of septic shock, including sepsis-induced immune suppression, inflammasome activation, intestinal permeability, and the role of lipids and proprotein convertase subtilisin/kexin type 9. Current therapies aiming to eliminate the organisms causing septic shock, recent and ongoing trials in septic shock treatment, and potential new therapeutic strategies are also explored.

Update of Sepsis in the Intensive Care Unit.

Sepsis, the most common cause of admission to an intensive care unit (ICU), has had an increased incidence and prevalence over the last years with a simultaneous decrease in its short-term mortality. Sepsis survivors are more frequently discharged from hospital and often experience long-term outcomes such as late mortality, immune dysfunction, secondary infections, impaired quality of life, and unplanned readmissions. Early recognition and management of sepsis have challenged emergency care and critical care physicians and nurses. New sepsis definitions were produced and the Surviving Sepsis Campaign (SSC) 2016 was updated recently. Although hospital readmissions after sepsis are common, associated risk factors and how to manage patients who survive an episode of sepsis still need clarification. The immune dysfunction caused by sepsis/septic shock is complex, persistent, affects inflammatory and anti-inflammatory systems, and might be associated with long-term outcomes of sepsis. Several randomized controlled trials (RCT) that analyzed new (and old) interventions in sepsis/septic shock are discussed in this review in parallel with the SSC 2016 recommendations and other guidelines when relevant. RCTs addressing incidence, treatment, and prevention of important sepsis-associated organ dysfunction such as the acute respiratory distress syndrome, acute kidney injury, and brain dysfunction are highlighted. Finally, we briefly discuss the need for novel targets, predictive biomarkers, and new designs of RCTs in sepsis.

Proteins of the mitotic checkpoint and spindle are related to chromosomal instability and unfavourable prognosis in patients with myelodysplastic syndrome.

AIMS: To study the immunoexpression of proteins related to the mitotic checkpoint (cell division cycle 20 (CDC20), mitotic arrest deficient 2 (MAD2)) and the mitotic spindle (Aurora-B) in patients with myelodysplastic syndrome (MDS). METHODS: Protein expression was analysed in bone marrow tissue samples from 40 patients with MDS using immunohistochemistry. Prognostic markers (transfusion dependency, depth of cytopenias, chromosomal abnormalities and survival) were also studied. RESULTS: Higher MAD2 expression was observed among patients with platelets <50×10(9)/L than among patients with platelets ≥50×10(9)/L (42.6±22.8% vs 22.7±19.1%, respectively). Higher CDC20 expression was identified among patients with three dysplasias compared with patients who presented with one or two dysplasias (33.9±24.1% vs 10.5±5.7% vs 12.8±7.8%, respectively), among patients who exhibited a complex versus non-complex karyotype (50.0±30.2% vs 18.4±14%, respectively) and among patients with platelets <50×10(9)/L vs platelets ≥50×10(9)/L (38.2±26.2% vs 16.1±12.4%, respectively). Higher Aurora-B expression was found in patients with an abnormal versus normal karyotype (21.2±13.2% vs 7.5±5.0%, respectively). High expression of MAD2 and CDC20 (≥50%) was associated with severe thrombocytopenia. We also found statistically significant differences in the overall survival rate when comparing different degrees of CDC20, MAD2 and Aurora-B protein expression. CONCLUSIONS: To the best of our knowledge, this is the first report to demonstrate that these proteins are associated with chromosomal abnormalities and poor prognosis in patients with MDS.

Epidemiology of and factors associated with end-of-life decisions in a surgical intensive care unit.

OBJECTIVE: To investigate the epidemiology of and possible factors associated with end-of-life decisions in a surgical intensive care unit. DESIGN: Analysis of prospectively collected data. SETTING: University hospital surgical intensive care unit. PATIENTS: All patients admitted to the surgical intensive care unit between September 2002 and July 2006. MEASUREMENTS AND MAIN RESULTS: During the study period, 14,720 patients were admitted to the surgical intensive care unit (61.8 male; mean age, 62 yrs). The prevalence of end-of-life decisions was 2.7% (n = 398); 230 patients (1.6%) had a do-not-resuscitate order, 90 (0.6%) had a decision to withhold therapy, and 78 (0.5%) had a decision to withdraw life-supportive therapy. Patients with end-of-life decisions had higher severity scores on the day of intensive care unit admission, were mostly unplanned admissions, were older, and were more commonly referred from the emergency room or other hospitals compared to those who did not have an end-of-life decision. The prevalence of end-of-life decisions increased significantly with the severity of sepsis. An end-of-life decision was made for 29% of the patients who died in the intensive care unit. Intensive care unit and hospital mortality rates were 6.1% and 10.3%, respectively, overall, and 65.1% and 82.2%, respectively, in patients with an end-of-life decision. In multivariate analysis, older age, admission from another hospital, cirrhosis, sepsis syndromes, simplified acute physiology score II, and sequential organ failure assessment scores were independently associated with end-of-life decisions. CONCLUSIONS: Twenty-nine percent of patients who die in the surgical intensive care unit have an end-of-life decision. Severe sepsis/septic shock was associated with a 16-fold increased likelihood of having an end-of-life decision.