Lymphocyte Apoptosis, Caspase Activation and Inflammatory Response in Septic Shock

Exploring genetic loci linked to COVID-19 severity and immune response through multi-trait GWAS analyses

Introduction

COVID-19 severity has been linked to immune factors, with excessive immune responses like cytokine storms contributing to mortality. However, the genetic basis of these immune responses is not well understood. This study aimed to explore the genetic connection between COVID-19 severity and blood cell traits, given their close relationship with immunity.

Materials and methods

GWAS summary statistics for COVID-19 and blood cell counts were analyzed using Linkage Disequilibrium Score Regression (LDSC) to estimate genetic correlations and heritabilities. For traits with significant correlations, a Multi-Trait GWAS Analysis (MTAG) was performed to identify pleiotropic loci shared between COVID-19 and blood cell counts.

Results

Our MTAG analysis identified four pleiotropic loci associated with COVID-19 severity, five loci linked to hospitalized cases, and one locus related to general patients. Among these, two novel loci were identified in the high-risk population, with rs55779981 located near RAVER1 and rs73009538 near CARM1. In hospitalized patients, two previously unrecognized loci were detected, namely, rs115545251 near GFI1 and rs3181049 near RAVER1, while in general patients, rs11065822 near CUX2 emerged as a newly identified locus. We also identified potential target genes, including those involved in inflammation signaling (CARM1), endothelial dysfunction (INTS12), and antiviral immune response (RAVER1), which may require further investigation.

Conclusion

Our study offers insights into the genetic overlap between COVID-19 and immune factors, suggesting potential directions for future research and clinical exploration.

Association between blood caspase-9 concentrations and septic patient prognosis

BACKGROUND

There are few data on caspase‑9 (intrinsic apoptosis pathway initiating caspase) in septic patients. Higher serum caspase‑9 levels in septic patients than in healthy subjects have been found. However, there are no data on the prognosis of septic patients and blood caspase‑9 concentrations. Therefore, the objective of this study was to analyze the potential association between blood caspase‑9 concentrations and prognosis in septic patients.

METHODS

Three Spanish hospitals participated in the recruitment of septic patients admitted to intensive care units in this observational and prospective study. Serum caspase‑9 concentrations were determined at the time of sepsis diagnosis. The 30-day mortality was the outcome variable.

RESULTS

Higher Acute Phisiology and Chronic Health Evaluation(APACHE)-II (p < 0.001), Sepsis-related Organ Failure Assessment score (SOFA) (p < 0.001), serum lactic acid levels (p = 0.001), serum caspase‑9 levels (p < 0.001), age (p < 0.001), International normalized ratio (INR) (p = 0.001), rate of septic shock (p = 0.001), Activated partial thromboplastin time (aPTT) (p = 0.03), rate of diabetes mellitus (p = 0.04), and lower platelet counts (p = 0.01) were found in non-surviving (n = 80) than in surviving patients (n = 134). Multiple logistic regression analysis showed an association between serum caspase‑9 concentrations and mortality (Odds Ratio (OR) = 1.985; 95% Confidence Interval (CI) = 1.359-2.900; p < 0.001) regardless of age, SOFA, lactic acid and septic shock and history of diabetes mellitus. No significant differences were found when we compared area under ROC curves of serum caspase‑9 with SOFA (p = 0.92) and with lactic acid (p = 0.59).

CONCLUSIONS

The main novel finding of our study was the association between blood caspase‑9 concentrations and septic patient prognosis. However, our study showed some limitations (for example, the absence of data in respect to execution of Surviving Sepsis Campaign bundles); thus, more research could be interesting to confirm our preliminary findings.

Association of serum soluble Fas concentrations and mortality of septic patients

INTRODUCTION

Scarce data on Fas, one of the main receptors that activates the apoptosis extrinsic pathway, in septic patients exists. Higher blood soluble Fas (sFas) concentrations in non-survivor septic patients compared with survivors have been found in small studies; however, the association of blood sFas concentrations with mortality controlling for sepsis severity has not been stablished due to this small sample size in those studies. Thus, our main objective study was to determine whether an association between blood sFas concentrations and sepsis mortality controlling for sepsis severity exists.

METHODS

We included septic patients in this observational and prospective study carried out in three Spanish Intensive Care Units. We obtained serum samples at sepsis diagnosis sepsis for sFas levels determination.

RESULTS

Thirty-day non-surviving patients (n=85) compared to surviving patients (n=151) had higher serum sFas levels (p<0.001). We found in multiple logistic regression analysis an association of serum sFas levels with mortality controlling for age and SOFA (OR=1.004; 95% CI=1.002-1.006; p<0.001), and for age and APACHE-II (OR=1.004; 95% CI=1.002-1.006; p<0.001). Serum sFas levels showed and area under the curve for mortality prediction of 71% (95% CI=65-71%; p<0.001). Kaplan-Meier analysis showed higher mortality rate in patients with serum sFas levels>83.5ng/mL (Hazard ratio=3.2; 95% CI=2.1-5.0; p<0.001).

CONCLUSIONS

That an association between blood sFas concentrations and sepsis mortality controlling for sepsis severity exists was our main new finding study.

Leukocyte kinetics during the early stage acts as a prognostic marker in patients with septic shock in intensive care unit

The leukocytes play an important role in immune function during sepsis. We performed a retrospective study to investigate if leukocytes kinetics was associated with survival in critically ill patients with septic shock in intensive care unit (ICU).Patients with septic shock from January 1, 2014 to June 30, 2018 in our ICU were included. We extracted the demographic, clinical and laboratory data, comorbidities from our clinical database. The number of white blood cell, neutrophil and lymphocyte on day 1 and day 3 after diagnosis were collected and neutrophil to lymphocyte ratios (NLR) were calculated. Our primary outcome was 28-day mortality. Univariate and multivariate logistic regression models and cox proportional risk model were used to analyze the association between the leukocytes kinetics during first 3 days after ICU admission and the day-28 mortality.A total of 1245 septic shock patients with a 28-day mortality of 35.02% were included into analysis. There were no significant difference of lymphocyte number (0.83 ± 0.02 vs 0.80 ± 0.04, P = .552) between survival and non-survivals on day 1. However, the lymphocyte counts was significantly lower (0.95 ± 0.03 vs 0.85 ± 0.04, P = .024) on the third day. Both multivariate logistic and Cox regression analysis showed that lymphocyte counts on day 3 were associated with day-28 mortality. Moreover, Kaplan-Meier survival analysis revealed that increasing in lymphocyte counts and decreasing WBC, neutrophils and NLR during the first 3 days after diagnosis were associated with longer survival.Leukocytes kinetics during the first 3 days is a valuable prognostic marker in patients with septic shock in the ICU.

Association of serum soluble Fas concentrations and mortality of septic patients

INTRODUCTION

Scarce data on Fas, one of the main receptors that activates the apoptosis extrinsic pathway, in septic patients exists. Higher blood soluble Fas (sFas) concentrations in non-survivor septic patients compared with survivors have been found in small studies; however, the association of blood sFas concentrations with mortality controlling for sepsis severity has not been stablished due to this small sample size in those studies. Thus, our main objective study was to determine whether an association between blood sFas concentrations and sepsis mortality controlling for sepsis severity exists.

METHODS

We included septic patients in this observational and prospective study carried out in three Spanish Intensive Care Units. We obtained serum samples at sepsis diagnosis sepsis for sFas levels determination.

RESULTS

Thirty-day non-surviving patients (n=85) compared to surviving patients (n=151) had higher serum sFas levels (p<0.001). We found in multiple logistic regression analysis an association of serum sFas levels with mortality controlling for age and SOFA (OR=1.004; 95% CI=1.002-1.006; p<0.001), and for age and APACHE-II (OR=1.004; 95% CI=1.002-1.006; p<0.001). Serum sFas levels showed and area under the curve for mortality prediction of 71% (95% CI=65-71%; p<0.001). Kaplan-Meier analysis showed higher mortality rate in patients with serum sFas levels>83.5ng/mL (Hazard ratio=3.2; 95% CI=2.1-5.0; p<0.001).

CONCLUSIONS

That an association between blood sFas concentrations and sepsis mortality controlling for sepsis severity exists was our main new finding study.

Association between serum sFasL concentrations and sepsis mortality

BACKGROUND

There are scarce data on soluble Fas Ligand (sFasL), one of the main ligands that activate the apoptosis extrinsic pathway, in septic patients. In a small study of septic children were found higher plasma sFasL levels in non-survivors compared with survivors; however, an association between blood sFasL levels and mortality controlling for sepsis severity was not stablished due to the small sample size of the study. Therefore, the main objective of this study was to determine whether there is an association between blood sFasL concentrations and mortality in septic patients controlling for sepsis severity. Methods: Septic patients were included in this observational and prospective study conducted in three Spanish Intensive Care Units. Serum samples at diagnosis of sepsis were obtained for serum sFasL levels determination.

RESULTS

Thirty-day non-surviving patients (n = 85) with respect to surviving patients (n = 151) showed higher serum sFasL levels (p<.001). Multiple logistic regression analysis found an association between serum sFasL levels and mortality (odds ratio [OR] = 1.007; 95% confidence interval [CI] = 1.003-1.010; p<.001) after controlling for age, septic shock, SOFA, INR and aPTT. The area under the curve (AUC) for mortality prediction by serum sFasL levels was of 62% (95% CI = 56-69%; p=.003). In Kaplan-Meier analysis was found that patients with serum sFasL levels >109 pg/mL had a higher mortality rate (hazard ratio = 3.6; 95% CI = 1.93-6.78; p<.001).

CONCLUSIONS

The main new finding from our study was that serum sFasL concentrations were associated with mortality in septic patients controlling for sepsis severity. Highlights Blood sFasL concentrations were higher in non-survivor than in survivor patients. There is an association between blood sFasL concentrations and mortality in septic patients. Blood sFasL concentrations could predict mortality of septic patients.

The severe COVID-19: A sepsis induced by viral infection? And its immunomodulatory therapy

COVID-19 is known for its magical infectivity, fast transmission and high death toll based on the large number of infected people. From the perspective of the clinical manifestation, autopsy examination and pathophysiology, the essence of COVID-19 should be viewed as a sepsis induced by viral infection, and has the essential characteristics as sepsis induced by other pathogens. Therefore, in addition to etiological and supportive treatment, immunomodulatory therapy is also appropriate to severe COVID-19. Although there is still a lack of consensus on immunotherapy for sepsis so far, relatively rich experiences have been accumulated in the past decades, which will help us in the treatment of severe COVID-19. This article will elaborate immunotherapy of sepsis, though it may not be consistent.

Peculiarities of leukocyte apoptosis modulation in children with pyelonephritis

One of the leading places among inflammatory diseases of the urinary tract of children belongs to pyelonephritis, the course of which presents in most cases as a severe infectious disease threatening the patient’s life, which is the main reason for development of chronic kidney failure. This study was conducted to compare apoptosis stages in peripheral blood of children of different age categories with pyelonephritis depending on etiological factor and complications. The problem of mechanisms underlying immune system misregulation, especially functional activity of leukocytes in children with pyelonephritis, have not been explored in recent years. Assessment of leukocytes (neutrophils) apoptosis stages in peripheral blood of children of different age categories with pyelonephritis depending on complications and etiological factor was the aim of present study. The children's peripheral blood samples were analysed and assessed using a flow cytofluorimeter. The present study demonstrates an increase of the level of apoptotic cells at an early stage of apoptosis in children of all age categories with chronic pyelonephritis, which can be explained by associations of a wide range of pathogens and the presence of sequelae. An increase in the number of apoptotic cells in the late stage of apoptosis is observed in children aged 1 month – 8 years, in children 8–18 years, the amount of apoptotic cells is reduced by 1.5 times. The study of apoptosis stages allows complete characterization of the dynamics of the apoptotic process and supplementation of the pathogenesis of pyelonephritis in children. Such studies will make it possible to affect apoptosis modulation to regulate or correct it and encourage the finding of innovative solutions in the treatment related to influence on the immune response. We conclude that enhancement of peripheral blood leukocyte apoptosis in chronic form of pyelonephritis especially in young children is due to the polyetiology of this form of pyelonephritis and the development of complications.

Prognostic Significance of Preoperative Circulating Monocyte Count in Patients With Breast Cancer: Based on a Large Cohort Study

Growing evidence showed that inflammation response plays an important role in cancer development and progression, and absolute lymphocyte count (ALC), absolute monocyte count (AMC), and lymphocyte to monocyte ratio (LMR) have been used as parameters of systemic inflammation in several tumors. In this study, we evaluated the prognostic significance of preoperative ALC, AMC and LMR in breast cancer and 2000 patients between January 2002 and December 2008 at Sun Yat-Sen University Cancer Center were enrolled. Patients were grouped by the cut-off value according to the receiver operating characteristics (ROC) curve analysis. Kaplan-Meier analysis showed that patients with elevated AMC levels (>0.48 × 10/L) had shorter overall survival (OS, P < 0.001). In multivariate analysis, preoperative AMC was identified as an independent prognostic parameter for OS in breast cancer patients (hazard ratio = 1.374, 95% confidence interval: 1.045-1.807). Subgroup analyses revealed that AMC was an unfavorable prognostic factor in stage II-III breast cancer patients and Luminal B, human epithelial growth factor receptor-2 overexpressing subtype, and triple-negative breast cancer (all P < 0.05). Additionally, the prognostic value of ALC and LMR could not be proven in the current study. Preoperative AMC may serve as an easily available and low-priced parameter to predict the outcomes of breast cancer.

Uncontrolled sepsis: a systematic review of translational immunology studies in intensive care medicine

BACKGROUND

The design of clinical immunology studies in sepsis presents several fundamental challenges to improving the translational understanding of pathologic mechanisms. We undertook a systematic review of bed-to-benchside studies to test the hypothesis that variable clinical design methodologies used to investigate immunologic function in sepsis contribute to apparently conflicting laboratory data, and identify potential alternatives that overcome various obstacles to improve experimental design.

METHODS

We performed a systematic review of the design methodology employed to study neutrophil function (respiratory burst), monocyte endotoxin tolerance and lymphocyte apoptosis in the intensive care setting, over the past 15 years. We specifically focussed on how control samples were defined, taking into account age, gender, ethnicity, concomitant therapies, timing of sample collection and the criteria used to diagnose sepsis.

RESULTS

We identified 57 eligible studies, the majority of which (74%) used case-control methodology. Healthy volunteers represented the control population selected in 83% of studies. Comprehensive demographic data on age, gender and ethnicity were provided in ≤48% of case control studies. Documentation of diseases associated with immunosuppression, malignancy and immunomodulatory therapies was rare. Less than half (44%) of studies undertook independent adjudication for the diagnosis of sepsis while 68% provided microbiological data. The timing of sample collection was defined by highly variable clinical criteria. By contrast, surgical studies avoided many such confounders, although only one study in surgical patients monitored the study group for development of sepsis.

CONCLUSIONS

We found several important and common limitations in the clinical design of translational immunologic studies in human sepsis. Major elective surgery overcame many of these methodological limitations. The failure of adequate clinical design in mechanistic studies may contribute to the lack of translational therapeutic progress in intensive care medicine.

Pathways mediating resolution of inflammation: when enough is too much

Patients with critical illness, and in particular sepsis, are now recognized to undergo unifying, pathogenic disturbances of immune function. Whilst scientific and therapeutic focus has traditionally been on understanding and modulating the initial pro-inflammatory limb, recent years have witnessed a refocusing on the development and importance of immunosuppressive 'anti-inflammatory' pathways. Several mechanisms are known to drive this phenomenon; however, no overriding conceptual framework justifies them. In this article we review the contribution of pro-resolution pathways to this phenotype, describing the observed immune alterations in terms of either a failure of resolution of inflammation or the persistence of pro-resolution processes causing inappropriate 'injurious resolution'-a novel hypothesis. The dysregulation of key processes in critical illness, including apoptosis of infiltrating neutrophils and their efferocytosis by macrophages, are discussed, along with the emerging role of specialized cell subtypes Gr1(+) CD11b(+) myeloid-derived suppressor cells and CD4(+) CD25(+) FoxP3(+) T-regulatory cells.

Serum caspase-9 levels are increased in patients with amyotrophic lateral sclerosis

It is known that apoptosis may play a role in the pathophysiology of amyotrophic lateral sclerosis (ALS). Moreover, caspase-9 is implicated in the apoptosis pathway. The aim of the study was to investigate caspase-9 levels in serum of patients with ALS. The study involved 30 patients with ALS and 30 patients from the control group. The serum caspase-9 levels were measured using the enzyme-linked immunosorbent method. The study showed that caspase-9 levels are significantly increased in serum of the patients with ALS comparing to the control group (p < 0.05). There was a significant correlation of serum caspase-9 levels with severity of clinical state of ALS patients and duration of the disease (p < 0.05). The results indicate that caspase-9 may be implicated in pathomechanism of neurodegeneration in ALS.

Prevention of lymphocyte apoptosis in septic mice with cancer increases mortality

Lymphocyte apoptosis is thought to have a major role in the pathophysiology of sepsis. However, there is a disconnect between animal models of sepsis and patients with the disease, because the former use subjects that were healthy prior to the onset of infection while most patients have underlying comorbidities. The purpose of this study was to determine whether lymphocyte apoptosis prevention is effective in preventing mortality in septic mice with preexisting cancer. Mice with lymphocyte Bcl-2 overexpression (Bcl-2-Ig) and wild type (WT) mice were injected with a transplantable pancreatic adenocarcinoma cell line. Three weeks later, after development of palpable tumors, all animals received an intratracheal injection of Pseudomonas aeruginosa. Despite having decreased sepsis-induced T and B lymphocyte apoptosis, Bcl-2-Ig mice had markedly increased mortality compared with WT mice following P. aeruginosa pneumonia (85 versus 44% 7-d mortality; p = 0.004). The worsened survival in Bcl-2-Ig mice was associated with increases in Th1 cytokines TNF-α and IFN-γ in bronchoalveolar lavage fluid and decreased production of the Th2 cytokine IL-10 in stimulated splenocytes. There were no differences in tumor size or pulmonary pathology between Bcl-2-Ig and WT mice. To verify that the mortality difference was not specific to Bcl-2 overexpression, similar experiments were performed in Bim(-/-) mice. Septic Bim(-/-) mice with cancer also had increased mortality compared with septic WT mice with cancer. These data demonstrate that, despite overwhelming evidence that prevention of lymphocyte apoptosis is beneficial in septic hosts without comorbidities, the same strategy worsens survival in mice with cancer that are given pneumonia.

Cecal ligation and puncture-induced impairment of innate immune function does not occur in the absence of caspase-1

Mice that have been subjected to cecal ligation and puncture (CLP) have an impaired ability to clear a subsequent Pseudomonas aeruginosa challenge compared with that of sham CLP controls. We hypothesized that this outcome is dependent upon a caspase-1 mechanism and tested this hypothesis by measuring caspase-1 after CLP and by measuring clearance of a bacterial challenge in caspase-1-deficient mice after CLP. Wild-type mice subjected to CLP had increased caspase-1 activity as well as increased IL-1β and increased IL-18 production in splenocytes stimulated with heat-killed Pseudomonas and had increased plasma concentrations of IL-1β and IL-18 and impaired clearance of a P. aeruginosa challenge compared with sham controls. Healthy, uninjured caspase-1(-\-) mice did not differ from wild-type mice in their ability to clear a Pseudomonas challenge. However, unlike wild-type mice, caspase-1(-/-) mice subjected to CLP had no impairment of bacterial clearance of the Pseudomonas challenge, suggesting that caspase-1 induction after CLP played a role in impairment of bacterial clearance. This was further substantiated by the use of a specific caspase-1 inhibitor, Ac-YVAD-CMK. Wild-type mice treated with Ac-YVAD-CMK (10 mg/kg s.c. twice daily, initiated at time of CLP) did not have impaired clearance of a Pseudomonas challenge compared with that of sham mice and had significantly improved bacterial clearance compared with that of untreated CLP mice. Increased caspase-1 expression and activity after CLP injury appears to contribute to diminished innate immune function.

Sepsis biomarkers: a review

INTRODUCTION

Biomarkers can be useful for identifying or ruling out sepsis, identifying patients who may benefit from specific therapies or assessing the response to therapy.

METHODS

We used an electronic search of the PubMed database using the key words "sepsis" and "biomarker" to identify clinical and experimental studies which evaluated a biomarker in sepsis.

RESULTS

The search retrieved 3370 references covering 178 different biomarkers.

CONCLUSIONS

Many biomarkers have been evaluated for use in sepsis. Most of the biomarkers had been tested clinically, primarily as prognostic markers in sepsis; relatively few have been used for diagnosis. None has sufficient specificity or sensitivity to be routinely employed in clinical practice. PCT and CRP have been most widely used, but even these have limited ability to distinguish sepsis from other inflammatory conditions or to predict outcome.