Nuclear factor kappaB mediates a procoagulant response in monocytes during extracorporeal circulation

Cardiopulmonary bypass and VA-ECMO induced immune dysfunction: common features and differences, a narrative review

Cardiopulmonary bypass (CPB) and veno-arterial extracorporeal membrane oxygenation are critical tools in contemporary cardiac surgery and intensive care, respectively. While these techniques share similar components, their application contexts differ, leading to distinct immune dysfunctions which could explain the higher incidence of nosocomial infections among ECMO patients compared to those undergoing CPB. This review explores the immune modifications induced by these techniques, comparing their similarities and differences, and discussing potential treatments to restore immune function and prevent infections. The immune response to CPB and ECMO involves both humoral and cellular components. The kinin system, complement system, and coagulation cascade are rapidly activated upon blood contact with the circuit surfaces, leading to the release of pro-inflammatory mediators. Ischemia-reperfusion injury and the release of damage-associated molecular patterns further exacerbate the inflammatory response. Cellular responses involve platelets, neutrophils, monocytes, dendritic cells, B and T lymphocytes, and myeloid-derived suppressor cells, all of which undergo phenotypic and functional alterations, contributing to immunoparesis. Strategies to mitigate immune dysfunctions include reducing the inflammatory response during CPB/ECMO and enhancing immune functions. Approaches such as off-pump surgery, corticosteroids, complement inhibitors, leukocyte-depleting filters, and mechanical ventilation during CPB have shown varying degrees of success in clinical trials. Immunonutrition, particularly arginine supplementation, has also been explored with mixed results. These strategies aim to balance the inflammatory response and support immune function, potentially reducing infection rates and improving outcomes. In conclusion, both CPB and ECMO trigger significant immune alterations that increase susceptibility to nosocomial infections. Addressing these immune dysfunctions through targeted interventions is essential to improving patient outcomes in cardiac surgery and critical care settings. Future research should focus on refining these strategies and developing new approaches to better manage the immune response in patients undergoing CPB and ECMO.

Inflammatory Progression in Patients Undergoing Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is identified as a novel therapeutic strategy that offers short-term support to the metabolism of the heart and lungs in humans. Recently, the clinical centers, which provide ECMO has increased rapidly worldwide. The indications for the use of ECMO in daily clinical practice were broadened dynamically. However, even with the widespread adoption of ECMO, it still remains significant morbidity and mortality, and the underlying mechanisms are still not elucidated. Notably, one of the vital complications during ECMO was proposed as the inflammatory progression within the extracorporeal circulation. via the development of inflammatory response, patients with ECMO may further suffer from systemic inflammatory response syndrome (SIRS), posing serious risks to human health. Recently, growing evidence confirmed that through exposure of blood into the ECMO circuit could lead to the stimulation of the immune system which also facilitated the inflammatory response and systemic impaired. In the current review, the pathological development of inflammatory progression in patients with ECMO is well-listed. Furthermore, the relationship between immune-related activation and the development of inflammation is also summarized, which may further help us to decide the therapeutic strategies in daily clinical practice.

Autoimmune and autoinflammatory conditions after COVID-19 vaccination. New case reports and updated literature review

Autoimmunity linked to COVID-19 immunization has been recorded throughout the pandemic. Herein we present six new patients who experienced relapses of previous autoimmune disease (AD) or developed a new autoimmune or autoinflammatory condition following vaccination. In addition, we documented additional cases through a systematic review of the literature up to August 1st, 2022, in which 464 studies (928 cases) were included. The majority of patients (53.6%) were women, with a median age of 48 years (IQR: 34 to 66). The median period between immunization and the start of symptoms was eight days (IQR: 3 to 14). New-onset conditions were observed in 81.5% (n: 756) of the cases. The most common diseases associated with new-onset events following vaccination were immune thrombocytopenia, myocarditis, and Guillain-Barré syndrome. In contrast, immune thrombocytopenia, psoriasis, IgA nephropathy, and systemic lupus erythematosus were the most common illnesses associated with relapsing episodes (18.5%, n: 172). The first dosage was linked with new-onset events (69.8% vs. 59.3%, P = 0.0100), whereas the second dose was related to relapsing disease (29.5% vs. 59.3%, P = 0.0159). New-onset conditions and relapsing diseases were more common in women (51.5% and 62.9%, respectively; P = 0.0081). The groups were evenly balanced in age. No deaths were recorded after the disease relapsed, while 4.7% of patients with new-onset conditions died (P = 0.0013). In conclusion, there may be an association between COVID-19 vaccination and autoimmune and inflammatory diseases. Some ADs seem to be more common than others. Vaccines and SARS-CoV-2 may induce autoimmunity through similar mechanisms. Large, well-controlled studies are warranted to validate this relationship and assess additional variables such as genetic and other environmental factors.

Coagulopathies after Vaccination against SARS-CoV-2 May Be Derived from a Combined Effect of SARS-CoV-2 Spike Protein and Adenovirus Vector-Triggered Signaling Pathways

Novel coronavirus SARS-CoV-2 has resulted in a global pandemic with worldwide 6-digit infection rates and thousands of death tolls daily. Enormous efforts are undertaken to achieve high coverage of immunization to reach herd immunity in order to stop the spread of SARS-CoV-2 infection. Several SARS-CoV-2 vaccines based on mRNA, viral vectors, or inactivated SARS-CoV-2 virus have been approved and are being applied worldwide. However, the recent increased numbers of normally very rare types of thromboses associated with thrombocytopenia have been reported, particularly in the context of the adenoviral vector vaccine ChAdOx1 nCoV-19 from Astra Zeneca. The statistical prevalence of these side effects seems to correlate with this particular vaccine type, i.e., adenoviral vector-based vaccines, but the exact molecular mechanisms are still not clear. The present review summarizes current data and hypotheses for molecular and cellular mechanisms into one integrated hypothesis indicating that coagulopathies, including thromboses, thrombocytopenia, and other related side effects, are correlated to an interplay of the two components in the vaccine, i.e., the spike antigen and the adenoviral vector, with the innate and immune systems, which under certain circumstances can imitate the picture of a limited COVID-19 pathological picture.

Extracorporeal life support and systemic inflammation

Extracorporeal life support (ECLS) encompasses a wide range of extracorporeal modalities that offer short- and intermediate-term mechanical support to the failing heart or lung. Apart from the daily use of cardiopulmonary bypass (CPB) in the operating room, there has been a resurgence of interest and utilization of veno-arterial and veno-venous extracorporeal membrane oxygenation (VA- and VV-ECMO, respectively) and extracorporeal carbon dioxide removal (ECCO₂R) in recent years. This might be attributed to the advancement in technology, nonetheless the morbidity and mortality associated with the clinical application of this technology is still significant. The initiation of ECLS triggers a systemic inflammatory response, which involves the activation of the coagulation cascade, complement systems, endothelial cells, leukocytes, and platelets, thus potentially contributing to morbidity and mortality. This is due to the release of cytokines and other biomarkers of inflammation, which have been associated with multiorgan dysfunction. On the other hand, ECLS can be utilized as a therapy to halt the inflammatory response associated with critical illness and ICU therapeutic intervention, such as facilitating ultra-protective mechanical ventilation. In addition to addressing the impact on outcome of the relationship between inflammation and ECLS, two different but complementary pathophysiological perspectives will be developed in this review: ECLS as the cause of inflammation and ECLS as the treatment of inflammation. This framework may be useful in guiding the development of novel therapeutic strategies to improve the outcome of critical illness.

Cell Type-Specific Roles of NF-κB Linking Inflammation and Thrombosis

The transcription factor NF-κB is a central mediator of inflammation with multiple links to thrombotic processes. In this review, we focus on the role of NF-κB signaling in cell types within the vasculature and the circulation that are involved in thrombo-inflammatory processes. All these cells express NF-κB, which mediates important functions in cellular interactions, cell survival and differentiation, as well as expression of cytokines, chemokines, and coagulation factors. Even platelets, as anucleated cells, contain NF-κB family members and their corresponding signaling molecules, which are involved in platelet activation, as well as secondary feedback circuits. The response of endothelial cells to inflammation and NF-κB activation is characterized by the induction of adhesion molecules promoting binding and transmigration of leukocytes, while simultaneously increasing their thrombogenic potential. Paracrine signaling from endothelial cells activates NF-κB in vascular smooth muscle cells and causes a phenotypic switch to a “synthetic” state associated with a decrease in contractile proteins. Monocytes react to inflammatory situations with enforced expression of tissue factor and after differentiation to macrophages with altered polarization. Neutrophils respond with an extension of their life span—and upon full activation they can expel their DNA thereby forming so-called neutrophil extracellular traps (NETs), which exert antibacterial functions, but also induce a strong coagulatory response. This may cause formation of microthrombi that are important for the immobilization of pathogens, a process designated as immunothrombosis. However, deregulation of the complex cellular links between inflammation and thrombosis by unrestrained NET formation or the loss of the endothelial layer due to mechanical rupture or erosion can result in rapid activation and aggregation of platelets and the manifestation of thrombo-inflammatory diseases. Sepsis is an important example of such a disorder caused by a dysregulated host response to infection finally leading to severe coagulopathies. NF-κB is critically involved in these pathophysiological processes as it induces both inflammatory and thrombotic responses.

An Analysis of Risk Factors for Hemolysis in Children on Extracorporeal Membrane Oxygenation

OBJECTIVES

Hemolysis is a known complication of pediatric extracorporeal membrane oxygenation associated with renal failure and mortality. We sought to identify predictors of hemolysis in pediatric extracorporeal membrane oxygenation patients and determine its influence on outcomes.

DESIGN

Retrospective, single-center study.

SETTING

Urban, quaternary care center pediatric and neonatal ICU.

PATIENTS

Ninety-six patients requiring extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Daily measurements of plasma-free hemoglobin were obtained while patients were on extracorporeal membrane oxygenation. Patients with a prior extracorporeal membrane oxygenation run, on extracorporeal membrane oxygenation for less than 24 hours, or without complete medical records were excluded from the study. Ninety-six patients met inclusion criteria, of which, 25 patients (26%) had plasma-free hemoglobin greater than 30 mg/dL. Of those patients, 15 of 25(60%) had plasma-free hemoglobin greater than 50 mg/dL, and 21 of 25(84%) occurred during the first 7 days on extracorporeal membrane oxygenation. Compared with patients without hemolysis, those with hemolysis were younger (0.2 mo [0.06-3.2 mo] vs 8.2 mo [0.6-86 mo]; p < 0.001), had a higher pericannulation international normalized ratio (3.9 [3.5-5.5] vs 2.6 [1.8-3.7]; p = 0.003), lower pericannulation platelet count (33 × 10/μL [22-42 × 10/μL] vs 61 × 10/μL [38-86 × 10/μL]; p < 0.001), and had a less negative inlet pressure (-3.5 mm Hg [-14 to 11.5 mm Hg] vs -19 mm Hg [-47 to 0 mm Hg]; p = 0.01). A greater proportion of patients with hemolysis had a heparin assay less than 0.2 mg/dL (50% vs 17%; p = 0.001) and had fluid removal via slow continuous ultrafiltration (32% vs 6%; p < 0.001). Patients with hemolysis had increased risk of in-hospital mortality (odds ratio 10.0; 95% CI 3.4-32; p < 0.001). On multivariable analysis, continuous ultrafiltration (odds ratio, 8.0; 95% CI, 1.9-42; p = 0.007) and pericannulation international normalized ratio greater than 3.5 (odds ratio, 7.2; 95% CI, 2.3-26; p = 0.001) were significantly associated with hemolysis.

CONCLUSIONS

Hemolysis is a common complication of pediatric extracorporeal membrane oxygenation. We found that patients with hemolysis (plasma-free hemoglobin > 30 mg/dL) had a 10-fold increase in in-hospital mortality. In our study cohort, hemolysis was associated with continuous ultrafiltration use, but not continuous renal replacement therapy. Additionally, our results suggest that the degree of coagulopathy (international normalized ratio > 3.5) at the time of cannulation influences hemolysis. Additional prospective studies are necessary to define further strategies to prevent hemolysis and improve outcomes in pediatric extracorporeal membrane oxygenation patients.

Melatonin Attenuates Pulmonary Hypertension in Chronically Hypoxic Rats

Chronic hypoxia induces pulmonary hypertension and vascular remodeling, which are clinically relevant to patients with chronic obstructive pulmonary disease (COPD) associated with a decreased level of nitric oxide (NO). Oxidative stress and inflammation play important roles in the pathophysiological processes in COPD. We examined the hypothesis that daily administration of melatonin (10 mg/kg) mitigates the pulmonary hypertension and vascular remodeling in chronically hypoxic rats. The right ventricular systolic pressure (RVSP) and the thickness of pulmonary arteriolar wall were measured from normoxic control, vehicle- and melatonin-treated hypoxic rats exposed to 10% O₂ for 14 days. Levels of markers for oxidative stress (malondialdhyde) and inflammation (tumor necrosis factor-α (TNFα), inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2)) and the expressions of total endothelial NO synthase (eNOS) and phosphorylated eNOS at serine1177 (ser1177) were determined in the lung tissue. We found that the RVSP and the thickness of the arteriolar wall were significantly increased in the vehicle-treated hypoxic animals with elevated levels of malondialdhyde and mRNA expressions of the inflammatory mediators, when compared with the normoxic control. In addition, the phosphorylated eNOS (ser1177) level was significantly decreased, despite an increased eNOS expression in the vehicle-treated hypoxic group. Melatonin treatment significantly attenuated the levels of RVSP, thickness of the arteriolar wall, oxidative and inflammatory markers in the hypoxic animals with a marked increase in the eNOS phosphorylation in the lung. These results suggest that melatonin attenuates pulmonary hypertension by antagonizing the oxidative injury and restoration of NO production.

The inflammatory response to extracorporeal membrane oxygenation (ECMO): a review of the pathophysiology

Extracorporeal membrane oxygenation (ECMO) is a technology capable of providing short-term mechanical support to the heart, lungs or both. Over the last decade, the number of centres offering ECMO has grown rapidly. At the same time, the indications for its use have also been broadened. In part, this trend has been supported by advances in circuit design and in cannulation techniques. Despite the widespread adoption of extracorporeal life support techniques, the use of ECMO remains associated with significant morbidity and mortality. A complication witnessed during ECMO is the inflammatory response to extracorporeal circulation. This reaction shares similarities with the systemic inflammatory response syndrome (SIRS) and has been well-documented in relation to cardiopulmonary bypass. The exposure of a patient’s blood to the non-endothelialised surface of the ECMO circuit results in the widespread activation of the innate immune system; if unchecked this may result in inflammation and organ injury. Here, we review the pathophysiology of the inflammatory response to ECMO, highlighting the complex interactions between arms of the innate immune response, the endothelium and coagulation. An understanding of the processes involved may guide the design of therapies and strategies aimed at ameliorating inflammation during ECMO. Likewise, an appreciation of the potentially deleterious inflammatory effects of ECMO may assist those weighing the risks and benefits of therapy.

Thrombosis in hematologic malignancies: risks and consequences

SUMMARY Thrombotic complications in hematologic malignancies have been found to be high among the various forms of cancer. Thrombosis not only increases the morbidity, but also has an adverse impact on survival. The pathogenesis among the different forms of hematologic malignancies is reviewed in this article. The thrombogenicity of the individual malignant cells, the tumor burden, treatment modalities and presence of comorbidities are among the major risk factors. These factors vary with the acute leukemias, lymphomas, multiple myeloma and myeloproliferative neoplasms. The thrombogenetic factors in the more common hematologic malignancies are discussed. Results of recent randomized controlled clinical trials are beginning to provide data for meaningful therapeutic guidelines on thromboprophylaxis. They also enable the clinician to assess the risk factors in each individual patient. More clinical trials are needed to provide better risk stratification and to devise risk-adapted treatment regimens.

Hematopoietic stem cell transplantation induces immunologic tolerance in renal transplant patients via modulation of inflammatory and repair processes

Background

Inducing donor-specific tolerance in renal transplant patients could potentially prevent allograft rejection and calcineurin inhibitor nephrotoxicity. Combined kidney and hematopoietic stem cell transplant from an HLA-matched donor is an exploratory and promising therapy to induce immune tolerance. Investigtion of molecular mechanisms involved in the disease is needed to understand the potential process of cell therapy and develop strategies to prevent this immunologic rejection.

Methods

We enrolled nine patients in a clinical study in which cryopreserved donor hematopoietic stem cells were infused on days 2, 4, and 6 after kidney transplantation. One month post-transplant, 4 plasma samples were collected from combined transplants (C + Tx), and 8 plasma samples from patients with kidney transplantation alone (Tx). High abundance proteins in plasma were depleted and the two-dimensional liquid chromatography-tandem mass spectrometry coupled with iTRAQ labeling was utilized to identify the protein profiling between the two groups. Clusters of up- and down-regulated protein profiles were submitted to MetaCore for the construction of transcriptional factors and regulation networks.

Results and Discussion

Among the 179 identified proteins, 65 proteins were found in C + Tx with at least a 2-fold change as compared with Tx. A subset of proteins related to the complement and coagulation cascade, including complement C3a,complement C5a, precrusors to fibrinogen alpha and beta chains,was significantly downregulated in C + Tx. Meanwhile, Apolipoprotein-A1(ApoA1), ApoC1, ApoA2, ApoE, and ApoB were significantly lower in Tx compared to C + Tx. Gene ontology analysis showed that the dominant processes of differentially expressed proteins were associated with the inflammatory response and positive regulation of plasma lipoprotein particle remodeling.

Conclusions

Thus, our study provides new insight into the molecular events in the hematopoietic stem cell-induced immunologic tolerance.

Low venous thromboembolic risk with bortezomib in multiple myeloma and potential protective effect with thalidomide/lenalidomide-based therapy: review of data from phase 3 trials and studies of novel combination regimens

Patients with multiple myeloma (MM) are at elevated risk of venous thromboembolism (VTE), specifically deep vein thrombosis (DVT) and pulmonary embolism (PE). VTE risk in MM is increased by various patient- and disease-related factors. The type of anti-MM therapy represents a key factor, with a substantially elevated VTE risk in patients treated with the immunomodulatory drugs (IMiDs) thalidomide or lenalidomide in combination with dexamethasone and/or chemotherapy; VTE risk with lenalidomide-dexamethasone is further increased with concomitant erythropoietin. By contrast, treatment with the proteasome inhibitor bortezomib, alone or in combination, does not increase VTE risk; rates of DVT/PE do not appear affected by the use of erythropoiesis-stimulating agents. Bortezomib has shown antihemostatic effects in patients with relapsed or refractory MM, which supports that it exerts antithrombotic actions and thus potentially provides a protective effect in combination with regimens with an elevated VTE risk. Herein, we review data from phase 3 trials of bortezomib- and/or IMiD-based therapy in frontline MM, together with other studies of novel combination regimens. Despite the confounding effect of variable VTE prophylaxis, bortezomib-based regimens were typically associated with DVT/PE rates of ≤5%, similar to those seen with melphalan-prednisone and dexamethasone, whereas IMiD-based bortezomib-free regimens were generally associated with higher rates. Direct comparisons of regimens of thrombogenic potential with or without bortezomib demonstrated lower VTE risk with bortezomib. Between-study comparisons of VTE risk support these findings. Taken together, these data confirm the low VTE risk associated with bortezomib and support a potential protective effect of bortezomib in combination with IMiD-based regimens associated with elevated VTE risk.

Protective effects of steroids in cardiac surgery: a meta-analysis of randomized double-blind trials

OBJECTIVE

Cardiac surgery and cardiopulmonary bypass (CPB) induce an acute inflammatory response contributing to postoperative morbidity. The use of steroids as anti-inflammatory agents in surgery using CPB has been tested in many trials and has been shown to have good anti-inflammatory effects but no clear clinical advantages for the lack of an adequately powered sample size. The aim of this study was to evaluate the effects of steroid treatment on mortality and morbidity after cardiac surgery.

DESIGN

A systematic meta-analysis of randomized double-blind trials (RDBs).

SETTING

A university hospital.

PARTICIPANTS

Adult patients who underwent cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

A trial search was performed through PubMed and Cochrane databases from 1966 to January 2009. Among 104 clinical trials reviewed, 31 RDB trials (1,974 patients) were considered suitable to be analyzed. A quality assessment of the trials was performed using the Jadad score. The types of steroid used in these trials were methylprednisolone (51.4%), dexamethasone (34.3%), hydrocortisone (5.7%), prednisolone (2.9%), or a combination of methylprednisolone and dexamethasone (5.7%). Steroid prophylaxis provided a protective effect preventing postoperative atrial fibrillation (odds ratio = 0.56; confidence interval [CI] 0.44-0.72, p < 0.0001), reducing postoperative blood loss (mean difference = -204.2 mL; CI from -287.4 to -121 mL; p < 0.0001), and reducing intensive care unit (mean difference = -6.6 hours; CI from -10.5 to -2.7 hours, p = 0.0007) and overall hospital stay (mean difference = -0.8 days; CI from -1.4 to -0.2 days, p = 0.01). Steroid prophylaxis had no effect on postoperative mortality, mechanical ventilation duration, re-exploration for bleeding, and postoperative infection.

CONCLUSIONS

A systematic review of RDB trials reveals that steroid prophylaxis may reduce morbidity after cardiac surgery and does not increase the risk of postoperative infections.

Understanding the inflammatory response to cardiac surgery

The systemic inflammatory response to cardiac surgery is common, and resultant impairment of multiple organ function is generally mild or subclinical due to physiological reserve within organ systems. Unfortunately, the changing profile of patients referred for surgery suggests that the systemic inflammatory response may prominently influence surgical outcome in the future. Older, co-morbid patients with more limited physiological reserve are being referred for complex lengthy procedures, and paediatric surgery has witnessed a shift to earlier complex primary correction or palliation involving long cardiopulmonary bypass times or a period of suboptimal organ perfusion using circulatory arrest or low flow cardiopulmonary bypass. Unique to cardiac surgery is the predictability of the inflammatory response, but prophylactic therapies have not translated into clinical benefit, which the preconditioning phenomenon may address.

The ubiquitin-proteasome system: a novel target for anticancer and anti-inflammatory drug research

The ubiquitin-proteasome system is responsible for the degradation of most intracellular proteins, including those that control cell cycle progression, apoptosis, signal transduction and the NF-κB transcriptional pathway. Aberrations in the ubiquitin-proteasome system underlie the pathogenesis of many human diseases, so both the ubiquitin-conjugating system and the 20S proteasome are important targets for drug discovery. This article presents a few of the most important examples of the small molecule inhibitors and modulators targeting the ubiquitin-proteasome system, their mode of action, and their potential therapeutic relevance in the treatment of cancer and inflammatory-related diseases.

New targeted therapies for treatment of thrombosis in antiphospholipid syndrome

Antiphospholipid (aPL) antibodies (Abs) are associated with thrombosis and pregnancy loss in antiphospholipid syndrome (APS), a disorder initially characterised in patients with systemic lupus erythematosus (SLE) but now known to occur in the absence of other autoimmune disease. There is strong evidence that aPL Abs are pathogenic in vivo, from studies of animal models of thrombosis, endothelial cell activation and pregnancy loss. In recent years, progress has been made in characterising the molecular basis of this pathogenicity, which includes direct effects on platelets, endothelial cells and monocytes as well as activation of complement. This review summarises the clinical manifestations of APS and current modalities of treatment, and explains recent advances in understanding the molecular events triggered by aPL Abs on target cells in coagulation pathways as well as effects of aPL Abs on complement activation. Based on this information and on additional scientific evidence using in vitro and in vivo models, new potential targeted therapies for treatment and/or prevention of thrombosis in APS are proposed and discussed.

In Vivo Effects of an Inhibitor of Nuclear Factor-Kappa B on Thrombogenic Properties of Antiphospholipid Antibodies

It has been shown that endothelial cell (EC) activation and tissue factor (TF) upregulation in EC and monocytes by antiphospholipid antibodies (aPL Abs) leads to a prothrombotic state and involves translocation of nuclear factor-kappa B (NF-kappaB). Here we examined the effects of an NF-kappaB inhibitor on aPL-induced thrombosis, TF activity, and EC in vivo. We treated CD1 mice with IgG from a patient with antiphospholipid syndrome (IgG-APS) or with control IgG (IgG-NHS). The adhesion of leukocytes (number of white blood cells) to EC in cremaster muscle (as an indication of EC activation) as well as the size of an induced thrombus in the femoral vein of the mice were examined. Some mice in each group were infused with 10 microM MG132 (an inhibitor of NF-kappaB). TF activity was determined using a chromogenic assay in homogenates of carotid arteries and in peritoneal cells of mice. In vivo, IgG-APS increased significantly the number of white blood cells adhering to ECs (4.7 +/- 2.2) when compared to control mice (1.5 +/- 0.8), and these effects were significantly reduced when mice were pretreated with MG132 (0.8 +/- 0.2). IgG-APS increased significantly the thrombus size and MG132 inhibited that effect (93%). Treatment of the mice with IgG-APS also induced significantly increased TF function in peritoneal cells and in homogenates of carotid arteries. Pretreatment of the mice with MG132 abrogated those effects significantly. Mice injected with IgG-APS or with IgM-APS with or without the inhibitor had medium-high titers of anticardiolipin antibodies in serum at the time of the surgical procedures. The data show that prothrombotic and proinflammatory properties of IgG-APS and IgM-APS are downregulated in vivo by an NF-kappaB inhibitor. These findings may be important in designing new modalities of targeted therapies to treat thrombosis in patients with APS.

Reinfusion of aspirated pericardial blood during CPB. Part II. Laparotomy sponges are hazardous parts of the CPB circuit?

Usually, cotton laparotomy sponges are discarded when they become blood soaked. During bypass surgery, however, they are often wrung out into the pericardial sac and the contents of the sac are aspirated into the cardiopulmonary bypass (CPB) circuit. After cardiopulmonary bypass, many patients give evidence of mental confusion, excessive bleeding, and systemic inflammatory response syndrome (SIRS). We believe that a possible cause is reinfusion of blood that has been activated by contact with laparotomy sponges and contains fibrin microemboli and thrombin. Thrombin production, soluble fibrin (SF) development, and fibrinogen disappearance were measured, over time, in model systems composed of increasing amounts (0-10-20 microL) of tissue factor (TF) in 4 ml of anticoagulated blood distributed through the interstices of a 49-cm(2) laparotomy sponge. Clotting occurred in all of the sponges. Clotting was accelerated by the presence of TF. Without TF, clotting occurred in an average of 28 min (range 17-39). With 10 and 20 microl TF, clotting occurred in 20 (range 11-27) and 13 (range 10-16) min, respectively. Thrombin at a level of approximately 16 NIHU/ml whole blood was present in several donors for 10-20 min after clotting was complete. If 120 ml of blood was to be wrung from a full-sized laparotomy sponge at this point in time, it could contain as much as 2000 units of thrombin.

Coagulation disorders of cardiopulmonary bypass: a review

BACKGROUND

Postoperative bleeding is one of the most common complications of cardiac surgery.

DISCUSSION

Extensive surgical trauma, prolonged blood contact with the artificial surface of the cardiopulmonary bypass (CPB) circuit, high doses of heparin, and hypothermia are all possible triggers of a coagulopathy leading to excessive bleeding. Platelet activation and dysfunction also occur and are caused mainly by heparin, hypothermia, and inadequate protamine administration. Heparin and protamine administration based on heparin concentrations as opposed to fixed doses may reduce coagulopathy and postoperative blood loss.

CONCLUSIONS

A better comprehension of the multifactorial mechanisms of activation of coagulation, inflammation, and fibrinolytic pathways during CPB may enable a more effective use of the technical and pharmaceutical options which are currently available.