Bioassay for Endothelial Damage Mediators Retrieved by Hemoadsorption

The role of hemoadsorption in cardiac surgery - a systematic review

BACKGROUND

Extracorporeal blood purification has been widely used in intensive care medicine, nephrology, toxicology, and other fields. During the last decade, with the emergence of new adsorptive blood purification devices, hemoadsorption has been increasingly applied during CPB in cardiac surgery, for patients at different inflammatory risks, or for postoperative complications. Clinical evidence so far has not provided definite answers concerning this adjunctive treatment. The current systematic review aimed to critically assess the role of perioperative hemoadsorption in cardiac surgery, by summarizing the current knowledge in this clinical setting.

METHODS

A literature search of PubMed, Cochrane library, and the database provided by CytoSorbents was conducted on June 1st, 2023. The search terms were chosen by applying neutral search keywords to perform a non-biased systematic search, including language variations of terms "cardiac surgery" and "hemoadsorption". The screening and selection process followed scientific principles (PRISMA statement). Abstracts were considered for inclusion if they were written in English and published within the last ten years. Publications were eligible for assessment if reporting on original data from any type of study (excluding case reports) in which a hemoadsorption device was investigated during or after cardiac surgery. Results were summarized according to sub-fields and presented in a tabular view.

RESULTS

The search resulted in 29 publications with a total of 1,057 patients who were treated with hemoadsorption and 988 control patients. Articles were grouped and descriptively analyzed due to the remarkable variability in study designs, however, all reported exclusively on CytoSorb® therapy. A total of 62% (18/29) of the included articles reported on safety and no unanticipated adverse events have been observed. The most frequently reported clinical outcome associated with hemoadsorption was reduced vasopressor demand resulting in better hemodynamic stability.

CONCLUSIONS

The role of hemoadsorption in cardiac surgery seems to be justified in selected high-risk cases in infective endocarditis, aortic surgery, heart transplantation, and emergency surgery in patients under antithrombotic therapy, as well as in those who develop a dysregulated inflammatory response, vasoplegia, or septic shock postoperatively. Future large randomized controlled trials are needed to better define proper patient selection, dosing, and timing of the therapy.

Major endothelial damage markers identified from hemadsorption filters derived from treated patients with septic shock - endoplasmic reticulum stress and bikunin may play a role

Introduction

In septic patients the damage of the endothelial barrier is decisive leading to circulatory septic shock with disseminated vascular coagulation, edema and multiorgan failure. Hemadsorption therapy leads to rapid resolution of clinical symptoms. We propose that the isolation of proteins adsorbed to hemadsorption devices contributes to the identification of mediators responsible for endothelial barrier dysfunction.

Material and methods

Plasma materials enriched to hemadsorption filters (CytoSorb®) after therapy of patients in septic shock were fractionated and functionally characterized for their effect on cell integrity, viability, proliferation and ROS formation by human endothelial cells. Fractions were further studied for their contents of oxidized nucleic acids as well as peptides and proteins by mass spectrometry.

Results

Individual fractions exhibited a strong effect on endothelial cell viability, the endothelial layer morphology, and ROS formation. Fractions with high amounts of DNA and oxidized DNA correlated with ROS formation in the target endothelium. In addition, defined proteins such as defensins (HNP-1), SAA1, CXCL7, and the peptide bikunin were linked to the strongest additive effects in endothelial damage.

Conclusion

Our results indicate that hemadsorption is efficient to transiently remove strong endothelial damage mediators from the blood of patients with septic shock, which explains a rapid clinical improvement of inflammation and endothelial function. The current work indicates that a combination of stressors leads to the most detrimental effects. Oxidized ssDNA, likely derived from mitochondria, SAA1, the chemokine CXCL7 and the human neutrophil peptide alpha-defensin 1 (HNP-1) were unique for their significant negative effect on endothelial cell viability. However, the strongest damage effect occurred, when, bikunin - cleaved off from alpha-1-microglobulin was present in high relative amounts (>65%) of protein contents in the most active fraction. Thus, a relevant combination of stressors appears to be removed by hemadsorption therapy which results in fulminant and rapid, though only transient, clinical restitution.

Impact of CytoSorb Hemoadsorption Therapy on Fluid Balance in Patients with Septic Shock

Recent in vitro studies have investigated the effects of hemoadsorption therapy on endothelial function in sepsis showing a reduction in markers of endothelial dysfunction, but, to this day, there are no clinical studies proving whether this approach could actually positively influence the disturbed vascular barrier function in septic conditions. We retrospectively analyzed data on administered fluid volumes and catecholamines in 124 septic shock patients. We collected catecholamine and volume requirements and calculated the volume balance within different time periods to obtain an assumption on the stability of the vascular barrier. Regarding the entire study cohort, our findings revealed a significant reduction in fluid balance at 72 h (T72) compared to both baseline (T0) and the 24 h mark (T24). Fluid balances from T72-T0 were significantly lower in hospital survivors compared with non-survivors. Patients who received a second catecholamine had a significantly lower in-hospital mortality. Our findings suggest that the applied treatment regimen including hemoadsorption therapy is associated with a reduced positive fluid balance paralleled by reductions in vasopressor needs, suggesting a potential positive effect on endothelial integrity. These results, derived from a large cohort of patients, provide valuable insights on the multiple effects of hemoadsorption treatment in septic shock patients.

Proteins Adsorbed during Intraoperative Hemoadsorption and Their In Vitro Effects on Endothelium

(1) Background: Hemoadsorption is a method of blood purification with a wide spectrum of indications. Pre-emptive use of hemoadsorption in patients undergoing heart surgery with cardiopulmonary bypass is considered to reduce the risk of postoperative systemic inflammatory response syndrome. The current study aimed to identify the spectrum of blood proteins adsorbed on the polymer matrix of the CytoSorb hemoadsorption system and to investigate their influence on cultured endothelial cells in vitro. (2) Methods: Adsorbers used for intraoperative hemoadsorption were obtained from patients undergoing on-pump valve surgery in acute endocarditis. Proteins were extracted from the adsorbers, purified, identified with mass-spectrometry and applied to cultured human aortic endothelial cells. (3) Results: A broad range of blood proteins were identified in the material eluted from the CytoSorb adsorber. When added to cultured ECs, these protein extracts caused severe reduction in cell viability and migration. After 24 h exposure, transcriptional changes with up-regulation of multiple metabolic regulators were observed and verified on the protein level. Genes responsible for control of mitosis were significantly down-regulated. (4) Conclusions: In summary, our data reveal that intraoperative hemoadsorption allows broad spectrum removal of a wide range of molecules eliciting endothelial damage.

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.

Case Report: Successful Use of Extracorporeal Therapies After ECMO Resuscitation in a Pediatric Kidney Transplant Recipient

The combination of extracorporeal membrane oxygenation (ECMO) and extracorporeal blood purification in children is rarely used due to small total blood volumes, risks of hemodynamic instability and a negative association between volume of blood transfusion and patient outcome. To our knowledge, this is the first description of a multimodal extracorporeal detoxication in the setting of ECMO in a post-kidney-transplant child on immunosuppression. We describe a case of a 30-months old child, who was extracorporeally resuscitated after cardiac arrest during kidney transplantation surgery and additionally treated with a number of extracorporeal blood purification methods (plasma exchange, CytoSorb, and lipopolysaccharide adsorption) in the setting of immunosuppression therapy. This case report shows the successful use of multimodal extracorporeal therapies for a good patient outcome. The lack of response to CytoSorb therapy might suggest an occult infection and not necessarily failure of treatment.