Purinergic P2X7 receptor expression increases in leukocytes from intra-abdominal septic patients.

Inflammation is a tightly coordinated response of the host immune system to bacterial and viral infections, triggered by the production of inflammatory cytokines. Sepsis is defined as a systemic inflammatory response followed by immunosuppression of the host and organ dysfunction. This imbalance of the immune response increases the risk of mortality of patients with sepsis, making it a major problem for critical care units worldwide. The P2X7 receptor plays a crucial role in activating the immune system by inducing the activation of peripheral blood mononuclear cells. In this study, we analyzed a cohort of abdominal origin septic patients and found that the expression of the P2X7 receptor in the plasma membrane is elevated in the different subsets of lymphocytes. We observed a direct relationship between the percentage of P2X7-expressing lymphocytes and the early inflammatory response in sepsis. Additionally, in patients whose lymphocytes presented a higher percentage of P2X7 surface expression, the total lymphocytes populations proportionally decreased. Furthermore, we found a correlation between elevated soluble P2X7 receptors in plasma and inflammasome-dependent cytokine IL-18. In summary, our work demonstrates that P2X7 expression is highly induced in lymphocytes during sepsis, and this correlates with IL-18, along with other inflammatory mediators such as IL-6, IL-8, and procalcitonin.

Whole Blood Platelet Aggregation Assessed by ROTEM Platelet Equipment in Healthy Volunteers from Southern Europe: A Verification Study.

BACKGROUND: This study aimed to verify the reference intervals (RIs) recently established in the Danish population for platelet aggregation induced by a specific agonist of the rotational thromboelastometry (ROTEM) platelet impedance aggregometer. Our local results were also compared with those published by the manufacturer. METHODS: This prospective study included healthy blood donors. Subjects with a history of coagulopathy, those on antiplatelet/anticoagulant therapy, or those taking nonsteroidal anti-inflammatory drugs were excluded. Blood samples were collected for ROTEM® platelet arachidonic acid thromboelastometry (ARATEM), adenosine-di-phosphate thromboelastometry (ADPTEM), and thrombin receptor-activating peptide-6 thromboelastometry (TRAPTEM). The parameters determined were the area under the curve (AUC, ohm·min), maximum amplitude at 6 min (A6, ohm), and maximum slope (MS, ohm/min). Values are expressed as 2.5th-97.5th percentiles. Comparisons are expressed as local vs Danish and manufacturer population RIs. Number (n) and percentage (%) of local tests below (<2.5th percentile) of the Danish and manufacturer population are shown. RESULTS: Forty donors (19 male; mean, 58 [range: 56 to 60] years) were included. There were no differences between our results and those published for the Danish population. In contrast, all ARATEM and ADPTEM values were lower in the local vs manufacturer group. CONCLUSIONS: Our results confirm those published for the Danish population, with respect to the ROTEM platelet aggregometer. CLINICALTRIALS.GOV REGISTRATION NUMBER: NCT02652897.

Current perspective on fibrinogen concentrate in critical bleeding.

INTRODUCTION: . Massive hemorrhage continues to be a treatable cause of death. Its management varies from prefixed ratio-driven administration of blood components to goal-directed therapy based on point-of-care testing and administration of coagulation factor concentrates. AREAS COVERED: . We review the current role of fibrinogen concentrate (FC) for the management of massive hemorrhage, either administered without coagulation testing in life-threatening hemorrhage, or within an algorithm based on viscoelastic hemostatic assays and plasma fibrinogen level. We identified relevant guidelines, meta-analyzes, randomized controlled trials, and observational studies that included indications, dosage, and adverse effects of FC, especially thromboembolic events. EXPERT OPINION: . Moderate- to high-grade evidence supports the use of FC for the treatment of severe hemorrhage in trauma and cardiac surgery; a lower grade of evidence is available for its use in postpartum hemorrhage and end-stage liver disease. Pre-emptive FC administration in non-bleeding patients is not recommended. FC should be administered early, in a goal-directed manner, guided by early amplitude of clot firmness parameters (A5- or A10-FIBTEM) or hypofibrinogenemia. Further investigation is required into the early use of FC, as well as its potential advantages over cryoprecipitate, and whether or not its administration at high doses leads to a greater risk of adverse events.

A prospective study on the correlation between thromboelastometry and standard laboratory tests - influence of type of surgery and perioperative sampling times.

This prospective study aimed at investigating the influence of surgery type and perioperative sampling times on the correlations between rotational thromboelastometry (ROTEM) parameters and standard laboratory coagulation tests assessing comparable coagulation phases. Patients undergoing glioblastoma multiforme resection (GBR group, n = 60) or laparoscopic colon cancer resection (CCR group, n = 40) were prospectively included. Blood samples for ROTEM and laboratory assessments were consecutively drawn within 24-hours prior to surgery (baseline), and at 2, 24 and 48-hours after surgery. Correlations between perioperative ExTEM clotting-time (CT-exTEM) and prothrombin time (PT), and between FibTEM maximum clot firmness (MCF-fibTEM) with and plasma fibrinogen (pFB) concentration (Clauss method), were evaluated using the Spearman's rho test. The efficiency of recommended cut-offs of CT-exTEM (>75 s) and MCF-fibTEM (<10 mm) for predicting a prolonged PT (>15 s) or a low pFB (<2 g/L), respectively, was assessed using Receiver-Operator Characteristic curves. Correlations between CT-exTEM and PT were weak in GBR (rho = 0.25 [0.12-0.38], p < .01), and very weak in CCR (rho = 0.06 [-0.12-0.27]). Those between MCF-fibTEM and pFB, were strong in both GBR (rho = 0.69 [0.61-0.76], p < .01) and CCR (rho = 0.70 [0.60-0.78], p < .01). These correlations remained largely unchanged over the studied perioperative period in both groups. Recommended CT-exTEM and MCF-fibTEM cut-offs had poor sensitivity for predicting a prolonged PT (17% [8-31]) or a low pFB (46% [32-62]), without group-related differences. Neither the type of surgery nor the perioperative sampling times had a significant influence on the correlations between ROTEM parameters and standard laboratory tests. ClinicalTrials.gov ID: NCT02652897.

Relationship of thromboelastography and conventional clotting test values with severe bleeding in critically ill patients with coagulopathy: A prospective study.

INTRODUCTION: This study aimed to ascertain the associations of thromboelastography (TEG® ) and standard laboratory test (SLTs) values with the presence of bleeding in critically ill patients with known coagulopathy. METHODS: Three groups of coagulopathic patients with (a) hepatic failure, (b) postoperative period after prolonged cardiac surgery, and (c) complex abdominal surgery with sepsis were prospectively included in this study. On intensive care unit (ICU) admission, patients were stratified into two groups according to whether they had major bleeding (MB) (evident overt bleeding, important bleeding apparent on imaging studies, and/or need for moderate-massive blood transfusion and hemodynamic instability). Blood samples were drawn for the SLTs (international normalized ratio [INR], activated partial thromboplastin time [aPTT], platelet count, and fibrinogen level [Clauss]) and TEG whole blood coagulation assays. Receiver operating characteristic (ROC) curves were generated to determine the efficiency of TEG and SLTs for detecting bleeding. The correlations between SLTs and TEG parameters with similar coagulation profiles were evaluated by Spearman rank-order analysis. RESULTS: Eighty-three patients were included, and bleeding was confirmed in 45 (54%). The fibrinogen level demonstrated the best accuracy for detecting bleeding with an area under the curve and 95% confidence intervals [AUC (95% CI)] of 0.74 (0.63-0.85) with the best cutoff value of ≤ 2 g/L. Regarding TEG-MA, the AUC (CI) obtained with the optimal cutoff value of ≤ 51 mm was 0.68 (0.56-0.80). CONCLUSIONS: Both conventional clotting tests and TEG values were poorly associated with bleeding in this critically ill cohort of patients with coagulopathy.

P2X7 receptor induces mitochondrial failure in monocytes and compromises NLRP3 inflammasome activation during sepsis.

Sepsis is characterized by a systemic inflammatory response followed by immunosuppression of the host. Metabolic defects and mitochondrial failure are common in immunocompromised patients with sepsis. The NLRP3 inflammasome is important for establishing an inflammatory response after activation by the purinergic P2X7 receptor. Here, we study a cohort of individuals with intra-abdominal origin sepsis and show that patient monocytes have impaired NLRP3 activation by the P2X7 receptor. Furthermore, most sepsis-related deaths are among patients whose NLRP3 activation is profoundly altered. In monocytes from sepsis patients, the P2X7 receptor is associated with mitochondrial dysfunction. Furthermore, activation of the P2X7 receptor results in mitochondrial damage, which in turn inhibits NLRP3 activation by HIF-1α. We show that mortality increases in a mouse model of sepsis when the P2X7 receptor is activated in vivo. These data reveal a molecular mechanism initiated by the P2X7 receptor that contributes to NLRP3 impairment during infection.