Polystyrene-Divinylbenzene-Based Adsorbents Reduce Endothelial Activation and Monocyte Adhesion Under Septic Conditions in a Pore Size-Dependent Manner

Real-World Outcomes of Hemoadsorption with CytoSorb® in Patients with Septic Shock: Insights from a Single-Center Study

BackgroundHemoadsorption is currently employed to treat septic shock and other clinical conditions involving massive inflammatory mediator release. CytoSorb®, a device utilizing synthetic resin microbeads, provides a large adsorption surface for blood purification. This study aimed to review the clinical course of patients with septic shock treated with CytoSorb® in our hospital's intensive care unit (ICU).Patients and MethodsThis study retrospectively analyzed the clinical course of patients with septic shock treated with CytoSorb®, focusing on treatment timing and the volume of blood processed.ResultsBetween July 1, 2016, and December 31, 2023, 175 patients (106 men, 69 women; median age: 67 years, interquartile [IQR]: 58-85) received CytoSorb® therapy. Survivors exhibited a significantly lower simplified acute physiology score at admission than nonsurvivors. CytoSorb® was initiated within 24 h of shock onset in 102 patients (58%, early starters) and between 25 and 48 h in 73 patients (42%, late starters). Hemodynamic improvements elevated mean arterial pressure and reduced lactate, procalcitonin, C-reactive protein, sequential organ failure assessment scores, and noradrenaline doses in survivors. These effects were more pronounced in early starters receiving intensive treatment, who also demonstrated significantly lower lactate levels and higher mean arterial pressure at the end of therapy. Overall, 86 patients (49%) died in the ICU. Survivors underwent longer treatment durations and processed greater blood volumes than nonsurvivors.ConclusionsIn patients with septic shock treated with CytoSorb® within 48 h of onset, treatment intensity-rather than timing-was associated with lower ICU mortality rates.

Application of Human Plasma/Serum to Cell Culture In Vitro: A Translational Research Approach to Better Define Disease Mechanisms

In vitro cell culture experiments play an important role in medical research. Various cellular mechanisms and signaling pathways have been identified with in vitro experimental techniques. Unfortunately, the clinical and translational impact of these studies is often limited due to their inability to closely resemble physiological or pathophysiological milieus in cell culture and the use of unrealistic experimental conditions. Thus, further developments must be made to improve the translation of in vitro cell culture work. The application of human plasma or serum as a stimulus for cells, human or otherwise, is a relatively new approach that ultimately overcomes many of the in vitro limitations and provides a more physiologically relevant model. While this technique has been used for the investigation of various diseases and pharmacological mechanisms, discrepancies remain regarding the appropriate methodologies. This review provides insight into recent findings through the application of human plasma or serum as stimuli, as well as an analysis of methodological considerations and suggestions for future directions.

Beyond Pattern Recognition: TLR2 Promotes Chemotaxis, Cell Adhesion, and Migration in THP-1 Cells

The interaction between monocytes and endothelial cells in inflammation is central to chemoattraction, adhesion, and transendothelial migration. Key players, such as selectins and their ligands, integrins, and other adhesion molecules, and their functions in these processes are well studied. Toll-like receptor 2 (TLR2), expressed in monocytes, is critical for sensing invading pathogens and initiating a rapid and effective immune response. However, the extended role of TLR2 in monocyte adhesion and migration has only been partially elucidated. To address this question, we performed several functional cell-based assays using monocyte-like wild type (WT), TLR2 knock-out (KO), and TLR2 knock-in (KI) THP-1 cells. We found that TLR2 promotes the faster and stronger adhesion of monocytes to the endothelium and a more intense endothelial barrier disruption after endothelial activation. In addition, we performed quantitative mass spectrometry, STRING protein analysis, and RT-qPCR, which not only revealed the association of TLR2 with specific integrins but also uncovered novel proteins affected by TLR2. In conclusion, we show that unstimulated TLR2 influences cell adhesion, endothelial barrier disruption, migration, and actin polymerization.

Survival of Patients Treated With Extracorporeal Hemoadsorption and Extracorporeal Membrane Oxygenation: Results From a Nation-Wide Registry

Extracorporeal hemoadsorption with the CytoSorb adsorber is increasingly being used during the past years. The use in combination with extracorporeal membrane oxygenation (ECMO) is feasible, but frequency of its use and outcomes have not been assessed in larger cohorts. We analyzed all patients treated with veno-venous (VV) ECMO either with or without CytoSorb in Germany from 2017 to 2019. Data were retrieved from a nationwide claim dataset collected by the Research Data Center of the Federal Bureau of Statistics. During this three-year episode, 7,699 patients were treated with VV ECMO. Among these, the number of CytoSorb-treated patients constantly increased from 156 (6.6%) in 2017 to 299 (11.8%) in 2019. In this large cohort hemoadsorption with the CytoSorb adsorber was associated with higher mortality and increased treatment costs. Due to limited information in the dataset about the severity of disease comparison of outcomes of patients treated with and without CytoSorb has to be interpreted with caution. Further studies have to examine if this finding is due to a negative effect of hemoadsorption with the CytoSorb device or is rather to be attributed to disease severity.

Targeting circulating high mobility group box-1 and histones by extracorporeal blood purification as an immunomodulation strategy against critical illnesses

Both high mobility group box-1 (HMGB1) and histones are major damage-associated molecular patterns (DAPMs) that mediate lethal systemic inflammation, activation of the complement and coagulation system, endothelial injury and multiple organ dysfunction syndrome in critical illnesses. Although accumulating evidence collectively shows that targeting HMGB1 or histones by their specific antibodies or inhibitors could significantly mitigate aberrant immune responses in multiple critically ill animal models, routine clinical use of such agents is still not recommended by any guideline. In contrast, extracorporeal blood purification, which has been widely used to replace dysfunctional organs and remove exogenous or endogenous toxins in intensive care units, may also exert an immunomodulatory effect by eliminating inflammatory mediators such as cytokines, endotoxin, HMGB1 and histones in patients with critical illnesses. In this review, we summarize the multiple immunopathological roles of HMGB1 and histones in mediating inflammation, immune thrombosis and organ dysfunction and discuss the rationale for the removal of these DAMPs using various hemofilters. The latest preclinical and clinical evidence for the use of extracorporeal blood purification to improve the clinical outcome of critically ill patients by targeting circulating HMGB1 and histones is also gathered.

Effect of extracorporeal hemoadsorption in critically ill patients with COVID-19: A narrative review

COVID-19 has been affecting the world unprecedentedly and will remain widely prevalent due to its elusive pathophysiological mechanism and the continuous emergence of new variants. Critically ill patients with COVID-19 are commonly associated with cytokine storm, multiple organ dysfunction, and high mortality. To date, growing evidence has shown that extracorporeal hemoadsorption can exert its adjuvant effect to standard of care by regulating immune homeostasis, reducing viremia, and decreasing endotoxin activity in critically ill COVID-19 cases. However, the selection of various hemofilters, timing of initiation and termination of hemoadsorption therapy, anticoagulation management of extracorporeal circuits, identification of target subgroups, and ultimate survival benefit remain controversial. The purpose of this narrative review is to comprehensively summarize the rationale for the use of hemoadsorption in critically ill patients with COVID-19 and to gather the latest clinical evidence in this field.

Polyzwitterionic Coating of Porous Adsorbents for Therapeutic Apheresis

Adsorbents for whole blood apheresis need to be highly blood compatible to minimize the activation of blood cells on the biomaterial surface. Here, we developed blood-compatible matrices by surface modification with polyzwitterionic polysulfobetainic and polycarboxybetainic coatings. Photoreactive zwitterionic terpolymers were synthesized by free-radical polymerization of zwitterionic, photoreactive, and fluorescent monomers. Upon UV irradiation, the terpolymers were photodeposited and mutually crosslinked on the surface of hydrophobic polystyrene-co-divinylbenzene and hydrophilic polyacrylamide-co-polyacrylate (DALI) beads. Fluorescent microscopy revealed coatings with an average thickness of 5 µm, which were limited to the bead surface. Blood compatibility was assessed based on polymer-induced hemolysis, coagulation parameters, and in vitro tests. The maintenance of the adsorption capacity after coating was studied in human whole blood with cytokines for polystyrene beads (remained capacity 25-67%) and with low-density lipoprotein (remained capacity 80%) for polyacrylate beads. Coating enhanced the blood compatibility of hydrophobic, but not of hydrophilic adsorbents. The most prominent effect was observed on coagulation parameters (e.g., PT, aPTT, TT, and protein C) and neutrophil count. Polycarboxybetaine with a charge spacer of five carbons was the most promising polyzwitterion for the coating of adsorbents for whole blood apheresis.

Cytokine adsorption in patients with acute-on-chronic liver failure (CYTOHEP)-a single center, open-label, three-arm, randomized, controlled intervention trial

Background

Liver cirrhosis is a major healthcare problem and the mortality rate is high. During recent years, systemic inflammation has been recognized as a major driver of hepatic decompensation and progression of liver cirrhosis to acute-on-chronic liver failure (ACLF). The aim of the CYTOHEP study is to assess the impact of extracorporeal hemoadsorption with the CytoSorb adsorber on serum bilirubin concentrations, humoral inflammation parameters, liver function parameters, and patient survival in patients with ACLF and acute kidney injury (AKI).

Methods

The CYTOHEP study is a prospective, single-center, open-label, three-arm, randomized, controlled intervention trial. Patients with ACLF and AKI stage 3 according to Kidney Disease: Improving Global Outcome (KDIGO) criteria will be randomized into three groups to be treated with (1) continuous renal replacement therapy (CRRT) and CytoSorb, (2) CRRT without CytoSorb, and (3) without both, CRRT and CytoSorb. In the hemoadsorption group, CytoSorb will be used for 72 h. The other groups receive standard of care with early or late initiation of CRRT, respectively. Primary endpoint of the study is serum bilirubin concentration after 72 h, important secondary endpoints are 30-day survival and a panel of inflammatory parameters.

Discussion

The CYTOHEP study is designed to evaluate the benefit of extracorporeal hemoadsorption in patients with ACLF. The results of this study will help to better understand the potential role of hemoadsorption for the treatment of ACLF and its impact on bilirubin levels, inflammatory parameters, and survival.

Trial registration

ClinicalTrials.gov NCT05019352. Registered on August 24, 2021. Deutsches Register Klinischer Studien (DRKS) DRKS00026082.

Adjuvant hemoadsorption therapy in patients with severe COVID-19 and related organ failure requiring CRRT or ECMO therapy: A case series

INTRODUCTION

Severe cases of the COVID-19 are often associated with the development of a fulminant sepsis-like state with a concomitant cytokine release syndrome. Recently, immunomodulating approaches to treat such a hyperinflammation have come into focus, including the use of new extracorporeal organ support therapies such as CytoSorb hemoadsorption designed to remove cytokines and other circulating mediators from blood.

PATIENTS AND METHODS

Thirteen critically ill COVID-19 patients with ARDS who received either ECMO therapy and/or CRRT with concomitant multiple organ failure were included. Hemoadsorption therapy was initiated once the patient had established-or was at high risk of developing-a hyperinflammatory state with marked hemodynamic instability or progressive lung failure. Levels of inflammatory markers, vasopressor requirements, oxygenation, and ventilation parameters were measured, as well as clinically relevant outcome measures.

RESULTS

Combined therapy was associated with a significant reduction in inflammatory mediators, hemodynamic stabilization with a concomitant decrease in requirements for vasoactive substances, and a pronounced improvement in lung function and the need for ventilatory support. Treatment appeared safe and well-tolerated.

CONCLUSIONS

In this case series of SARS-CoV-2 infected patients admitted to the intensive care unit with ARDS, we report effective interleukin (IL)-6 removal, reduced norepinephrine requirement, and improved lung function while receiving adjuvant, extracorporeal hemoadsorption therapy in the context of a multimodal treatment approach. The presented protocol for CytoSorb initiation may be a good foundation for the development of further prospective studies in the field and may eventually also be applied to other forms of hyperinflammatory ARDS.

Analysis of Inflammatory Mediator Profiles in Sepsis Patients Reveals That Extracellular Histones Are Strongly Elevated in Nonsurvivors

The timely recognition of sepsis and the prediction of its clinical course are challenging due to the complex molecular mechanisms leading to organ failure and to the heterogeneity of sepsis patients. Treatment strategies relying on a “one-fits-all” approach have failed to reduce mortality, suggesting that therapeutic targets differ between patient subgroups and highlighting the need for accurate analysis of the molecular cascades to assess the highly variable host response. Here, we characterized a panel of 44 inflammatory mediators, including cytokines, chemokines, damage-associated molecular patterns, and coagulation-related factors, as well as markers of endothelial activation in 30 patients suffering from renal failure in the course of sepsis. All patients received continuous veno-venous hemodialysis with either high cut-off filters or with standard filters, and mediators were quantified for all patients at the initiation of dialysis and after 24 h and 48 h. Mediator concentrations in individual patients ranged widely, demonstrating the heterogeneity of sepsis patients. None of the mediators correlated with SAPS III or TISS scores. The overall in-hospital mortality of the study population was 56.7% (57.1% vs. 56.3% for high cut-off vs. standard filter). The two filter groups differed regarding most of the mediator levels at baseline, prohibiting conclusions regarding the effect of standard filters versus high cut-off filters on mediator depletion. The elevation and correlation of damage-associated molecular patterns and markers of endothelial activation gave evidence of severe tissue damage. In particular, extracellular histones were strongly increased and were almost 30-fold higher in nonsurvivors as compared to survivors, indicating their diagnostic and prognostic potential.

Computer-aided design of short peptide ligands targeting tumor necrosis factor-alpha for adsorbent applications

A peptide ligand (T1: Ac-RKEM-NH₂) designed by a computer-aided method can enhance TNF-α adsorption from the plasma of rats with sepsis to PVA.

Mechanisms of endothelial activation in sepsis and cell culture models to study the heterogeneous host response

Sepsis is currently viewed as a fundamental disintegration of control functions from intracellular signalling to immunoregulatory and neuroendocrine mechanisms. The immediate threat in sepsis is invasive infection, and the need to activate immune defense mechanisms to clear the pathogen before irreparable damage occurs. In the process of pathogen elimination, however, the systemic host response to infection may cause collateral damage to the endothelium and may lead to the destruction of host tissues.A number of experimental models have been developed to monitor endothelial activation and to study endothelial dysfunction under septic conditions. Here, we review the application of these models to assess the highly variable host response in sepsis and to investigate the efficacy of adsorbent-based extracorporeal therapies. We also highlight the need for efficient diagnostic tools, which are indispensable to select patients who are likely to benefit from distinct adjunctive therapies.