Granzymes are serine proteases released by cytotoxic lymphocytes to induce apoptosis in virus-infected cells and tumor cells. Evidence is emerging that granzymes also play a role in controlling ...inflammation. Granzyme serum levels are elevated in patients with autoimmune diseases and infections, including sepsis. However, the function of extracellular granzymes in inflammation largely remains unknown. Here, we show that granzyme K (GrK) binds to Gram-negative bacteria and their cell-wall component lipopolysaccharide (LPS). GrK synergistically enhances LPS-induced cytokine release in vitro from primary human monocytes and in vivo in a mouse model of LPS challenge. Intriguingly, these extracellular effects are independent of GrK catalytic activity. GrK disaggregates LPS from micelles and augments LPS–CD14 complex formation, thereby likely boosting monocyte activation by LPS. We conclude that extracellular GrK is an unexpected direct modulator of LPS–TLR4 signaling during the antimicrobial innate immune response.
Sepsis is a common cause of acute respiratory distress syndrome (ARDS) associated with a high mortality. A panel of biomarkers (BMs) to identify septic patients at risk for developing ARDS, or at ...high risk of death, would be of interest for selecting patients for therapeutic trials, which could improve ARDS diagnosis and treatment, and survival chances in sepsis and ARDS. We measured nine protein BMs by ELISA in serum from 232 adult septic patients at diagnosis (152 required invasive mechanical ventilation and 72 had ARDS). A panel including the BMs RAGE, CXCL16 and Ang-2, plus PaO
/FiO
, was good in predicting ARDS (area under the curve = 0.88 in total septic patients). Best performing panels for ICU death are related to the presence of ARDS, need for invasive mechanical ventilation, and pulmonary/extrapulmonary origin of sepsis. In all cases, the use of BMs improved the prediction by clinical markers. Our study confirms the relevance of RAGE, Ang-2, IL-1RA and SP-D, and is novel supporting the inclusion of CXCL16, in BMs panels for predicting ARDS diagnosis and ARDS and sepsis outcome.
The acute respiratory distress syndrome (ARDS) is an acute inflammatory process of the lung caused by a direct or indirect insult to the alveolar-capillary membrane. Currently, ARDS is diagnosed ...based on a combination of clinical and physiological variables. The lack of a specific biomarker for ARDS is arguably one of the most important obstacles to progress in developing novel treatments for ARDS. In this article, we will review the current understanding of some appealing biomarkers that have been measured in human blood, bronchoalveolar lavage fluid (BALF) or exhaled gas that could be used for identifying patients with ARDS, for enrolling ARDS patients into clinical trials, or for better monitoring of patient's management. After a literature search, we identified several biomarkers that are associated with the highest sensitivity and specificity for the diagnosis or outcome prediction of ARDS: receptor for advanced glycation end-products (RAGE), angiopoietin-2 (Ang-2), surfactant protein D (SP-D), inteleukin-8, Fas and Fas ligand, procollagen peptide (PCP) I and III, octane, acetaldehyde, and 3-methylheptane. In general, these are cell-specific for epithelial or endothelial injury or involved in the inflammatory or infectious response. No biomarker or biomarkers have yet been confirmed for the diagnosis of ARDS or prediction of its prognosis. However, it is anticipated that in the near future, using biomarkers for defining ARDS, or for determining those patients who are more likely to benefit from a given therapy will have a major effect on clinical practice.
Summary
Sepsis is a complex syndrome related to an infection‐induced exaggerated inflammatory response, which is associated with a high mortality. Granzymes (Gzm) are proteases mainly found in ...cytotoxic lymphocytes that not only have a role in target cell death, but also as mediators of infection and inflammation. In this study we sought to analyse the intracellular expression of GzmA, B, M and K by flow cytometry in diverse blood lymphocyte populations from 22 sepsis patients, 12 non‐infected intensive care unit (ICU) patients and 32 healthy controls. Additionally, we measured GzmA and B plasma levels. Both groups of patients presented decreased percentage of natural killer (NK) cells expressing GzmA, B and M relative to healthy controls, while sepsis patients showed an increased proportion of CD8+ T cells expressing GzmB compared to controls. Expression of GzmK remained relatively unaltered between groups. Extracellular levels of GzmB were increased in non‐infected ICU patients relative to sepsis patients and healthy controls. Our results show differential alterations in intracellular expression of Gzm in sepsis patients and non‐infected critically ill patients compared to healthy individuals depending on the lymphocyte population and on the Gzm.
This study reports differential alterations in intracellular expression of granzymes A, B and M in sepsis patients and non‐infected critically ill patients compared to healthy individuals depending on the lymphocyte population and on the granzyme subtype. Expression of granzyme K remained relatively unaltered between groups
Sepsis is a severe systemic inflammatory response to infections that is accompanied by organ dysfunction and has a high mortality rate in adult intensive care units. Most genetic studies have ...identified gene variants associated with development and outcomes of sepsis focusing on biological candidates. We conducted the first genome-wide association study (GWAS) of 28-day survival in adult patients with sepsis.
This study was conducted in two stages. The first stage was performed on 687 European sepsis patients from the GEN-SEP network and 7.5 million imputed variants. Association testing was conducted with Cox regression models, adjusting by sex, age, and the main principal components of genetic variation. A second stage focusing on the prioritized genetic variants was performed on 2,063 ICU sepsis patients (1362 European Americans and 701 African-Americans) from the MESSI study. A meta-analysis of results from the two stages was conducted and significance was established at p < 5.0 × 10
. Whole-blood transcriptomic, functional annotations, and sensitivity analyses were evaluated on the identified genes and variants.
We identified three independent low-frequency variants associated with reduced 28-day sepsis survival, including a missense variant in SAMD9 (hazard ratio 95% confidence interval = 1.64 1.37-6.78, p = 4.92 × 10
). SAMD9 encodes a possible mediator of the inflammatory response to tissue injury.
We performed the first GWAS of 28-day sepsis survival and identified novel variants associated with reduced survival. Larger sample size studies are needed to better assess the genetic effects in sepsis survival and to validate the findings.
Mannose-binding lectin (MBL)-associated serine protease-2 (MASP-2) is an indispensable enzyme for the activation of the lectin pathway of complement. Its deficiency is classified as a primary ...immunodeficiency associated to pyogenic bacterial infections, inflammatory lung disease, and autoimmunity. In Europeans, MASP-2 deficiency, due to homozygosity for
c.359A > G
(p.D120G), occurs in 7 to 14/10,000 individuals. We analyzed the presence of the p.D120G mutation in adults (increasing the sample size of our previous studies) and children. Different groups of patients (1495 adults hospitalized with community-acquired pneumonia, 186 adults with systemic lupus erythematosus, 103 pediatric patients with invasive pneumococcal disease) and control individuals (1119 healthy adult volunteers, 520 adult patients without history of relevant infectious diseases, and a pediatric control group of 311 individuals) were studied. Besides our previously reported MASP-2-deficient healthy adults, we found a new p.D120G homozygous individual from the pediatric control group. We also reviewed p.D120G homozygous individuals reported so far: a total of eleven patients with a highly heterogeneous range of disorders and nine healthy controls (including our four MASP-2-deficient individuals) have been identified by chance in association studies. Individuals with complete deficiencies of several pattern recognition molecules of the lectin pathway (MBL, collectin-10 and collectin-11, and ficolin-3) as well as of MASP-1 and MASP-3 have also been reviewed. Cumulative evidence suggests that MASP-2, and even other components of the LP, are largely redundant in human defenses and that individuals with MASP-2 deficiency do not seem to be particularly prone to infectious or autoimmune diseases.
The role of mannose-binding lectin in pneumococcal infection García-Laorden, M Isabel; Rodríguez de Castro, Felipe; Solé-Violán, Jordi ...
European respiratory journal/The European respiratory journal,
01/2013, Letnik:
41, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The role of mannose-binding lectin (MBL) deficiency (MBL2; XA/O and O/O genotypes) in host defences remains controversial. The surfactant proteins (SP)-A1, -A2 and -D, other collectins whose genes ...are located near MBL2, are part of the first-line lung defence against infection. We analysed the role of MBL on susceptibility to pneumococcal infection and the existence of linkage disequilibrium (LD) among the four genes. We studied 348 patients with pneumococcal community-acquired pneumonia (P-CAP) and 2,110 controls. A meta-analysis of MBL2 genotypes in susceptibility to P-CAP and to invasive pneumococcal disease (IPD) was also performed. The extent of LD of MBL2 with SFTPA1, SFTPA2 and SFTPD was analysed. MBL2 genotypes did not associate with either P-CAP or bacteraemic P-CAP in the case-control study. The MBL-deficient O/O genotype was significantly associated with higher risk of IPD in a meta-analysis, whereas the other MBL-deficient genotype (XA/O) showed a trend towards a protective role. We showed the existence of LD between MBL2 and SP genes. The data do not support a role of MBL deficiency on susceptibility to P-CAP or to IPD. LD among MBL2 and SP genes must be considered in studies on the role of MBL in infectious diseases.
Acute respiratory distress syndrome (ARDS) is a lung inflammatory process caused mainly by sepsis. Most previous studies that identified genetic risks for ARDS focused on candidates with biological ...relevance. We aimed to identify novel genetic variants associated with ARDS susceptibility and to provide complementary functional evidence of their effect in gene regulation.
We did a case-control genome-wide association study (GWAS) of 1935 European individuals, using patients with sepsis-associated ARDS as cases and patients with sepsis without ARDS as controls. The discovery stage included 672 patients admitted into a network of Spanish intensive care units between January, 2002, and January, 2017. The replication stage comprised 1345 individuals from two independent datasets from the MESSI cohort study (Sep 22, 2008-Nov 30, 2017; USA) and the VISEP (April 1, 2003-June 30, 2005) and MAXSEP (Oct 1, 2007-March 31, 2010) trials of the SepNet study (Germany). Results from discovery and replication stages were meta-analysed to identify association signals. We then used RNA sequencing data from lung biopsies, in-silico analyses, and luciferase reporter assays to assess the functionallity of associated variants.
We identified a novel genome-wide significant association with sepsis-associated ARDS susceptibility (rs9508032, odds ratio OR 0·61, 95% CI 0·41-0·91, p=5·18 × 10
) located within the Fms-related tyrosine kinase 1 (FLT1) gene, which encodes vascular endothelial growth factor receptor 1 (VEGFR-1). The region containing the sentinel variant and its best proxies acted as a silencer for the FLT1 promoter, and alleles with protective effects in ARDS further reduced promoter activity (p=0·0047). A literature mining of all previously described ARDS genes validated the association of vascular endothelial growth factor A (VEGFA; OR 0·55, 95% CI 0·41-0·73; p=4·69 × 10
).
A common variant within the FLT1 gene is associated with sepsis-associated ARDS. Our findings support a role for the vascular endothelial growth factor signalling pathway in ARDS pathogenesis and identify VEGFR-1 as a potential therapeutic target.
Instituto de Salud Carlos III, European Regional Development Funds, Instituto Tecnológico y de Energías Renovables.
Supplemental oxygen is a supportive treatment in patients with sepsis to balance tissue oxygen delivery and demand in the tissues. However, hyperoxia may induce some pathological effects. We sought ...to assess organ damage associated with hyperoxia and its correlation with the production of reactive oxygen species (ROS) in a preclinical model of intra-abdominal sepsis. For this purpose, sepsis was induced in male, Sprague-Dawley rats by cecal ligation and puncture (CLP). We randomly assigned experimental animals to three groups: control (healthy animals), septic (CLP), and sham-septic (surgical intervention without CLP). At 18 h after CLP, septic (n=39), sham-septic (n=16), and healthy (n=24) animals were placed within a sealed Plexiglas cage and randomly distributed into four groups for continuous treatment with 21%, 40%, 60%, or 100% oxygen for 24 h. At the end of the experimental period, we evaluated serum levels of cytokines, organ damage biomarkers, histological examination of brain and lung tissue, and ROS production in each surviving animal. We found that high oxygen concentrations increased IL-6 and biomarkers of organ damage levels in septic animals, although no relevant histopathological lung or brain damage was observed. Healthy rats had an increase in IL-6 and aspartate aminotransferase at high oxygen concentration. IL-6 levels, but not ROS levels, are correlated with markers of organ damage. In our study, the use of high oxygen concentrations in a clinically relevant model of intra-abdominal sepsis was associated with enhanced inflammation and organ damage. These findings were unrelated to ROS release into circulation. Hyperoxia could exacerbate sepsis-induced inflammation, and it could be by itself detrimental. Our study highlights the need of developing safer thresholds for oxygen therapy.
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