Therapeutic Rationale for Endotoxin Removal with Polymyxin B Immobilized Fiber Column (PMX) for Septic Shock

Capnocytophaga canimorsus Meningitis Complicated by Septic Shock: The Use of Extracorporeal Blood Purification Techniques

Capnocytophaga canimorsus is a Gram-negative bacterium, commonly found as a commensal germ in the oral cavity of dogs and cats. It is an opportunistic pathogen, but, in specific situations, it can cause very severe diseases, including arthritis, pleuritis, endocarditis, sepsis, and, in extremely rare cases, meningoencephalitis. The predisposing situations include immunosuppression, liver cirrhosis, splenectomy, hemochromatosis, beta thalassemia major (Cooley's anemia), and alcohol abuse. In this report, we describe the case of a 48-year-old male patient, with a medical history of several predisposing conditions, who developed a severe case of meningoencephalitis caused by C. canimorsus, following a dog bite on his hand. The patient was successfully treated for his meningitis, but subsequently he developed a hospital-acquired septic shock from Acinetobacter baumannii, which was treated with targeted antibiotic therapy and sequential extracorporeal blood purification therapies using Oxiris™ and Toraymyxin™ hemofilters.

Challenges in Septic Shock: From New Hemodynamics to Blood Purification Therapies

Sepsis and septic shock are associated with high mortality, with diagnosis and treatment remaining a challenge for clinicians. Their management classically encompasses hemodynamic resuscitation, antibiotic treatment, life support, and focus control; however, there are aspects that have changed. This narrative review highlights current and avant-garde methods of handling patients experiencing septic shock based on the experience of its authors and the best available evidence in a context of uncertainty. Following the first recommendation of the Surviving Sepsis Campaign guidelines, it is recommended that specific sepsis care performance improvement programs are implemented in hospitals, i.e., "Sepsis Code" programs, designed ad hoc, to achieve this goal. Regarding hemodynamics, the importance of perfusion and hemodynamic coherence stand out, which allow for the recognition of different phenotypes, determination of the ideal time for commencing vasopressor treatment, and the appropriate fluid therapy dosage. At present, this is not only important for the initial timing, but also for de-resuscitation, which involves the early weaning of support therapies, directed elimination of fluids, and fluid tolerance concept. Finally, regarding blood purification therapies, those aimed at eliminating endotoxins and cytokines are attractive in the early management of patients in septic shock.

Mortality Risk Prediction in Abdominal Septic Shock Treated with Polymyxin-B Hemoperfusion: A Retrospective Cohort Study

Endotoxin, a component of the cell membrane of gram-negative bacteria, is a trigger for dysregulated inflammatory response in sepsis. Extracorporeal purification of endotoxin, through adsorption with polymyxin B, has been studied as a therapeutic option for sepsis. Previous studies suggest that it could be effective in patients with high endotoxin levels or patients with septic shock of moderate severity. Here, we perform a retrospective, single-centre cohort study of 93 patients suffering from abdominal septic shock treated with polymyxin-B hemoperfusion (PMX-HP) between 2015 and 2020. We compared deceased and surviving patients one month after the intervention using X² and Mann-Whitney U tests. We assessed the data before and after PMX-HP with a Wilcoxon single-rank test and a multivariate logistic regression analysis. There was a significant reduction of SOFA score in the survivors. The expected mortality using APACHE-II was 59.62%, whereas in our sample, the rate was 40.9%. We found significant differences between expected mortality and real mortality only for the group of patients with an SOFA score between 8 and 13. In conclusion, in patients with abdominal septic shock, the addition of PMX-HP to the standard therapy resulted in lower mortality than expected in the subgroup of patients with intermediate severity of illness.

Cytokine modulation in abdominal septic shock via the crucial role of IL-6 signaling in endothelial dysfunction

Background

Early recovery from shock improves prognosis in septic shock patients. We determined whether cytokine modulation by Continuous Renal Replacement Therapy (CRRT) following acute care surgery resulted in stable hemodynamics in them. To investigate our hypothesis, we measured proinflammatory cytokines IL-6, IL-1ra and the coagulation cascade activator plasminogen activator inhibitor-1 (PAI-1) following CRRT with polymyxin B immobilized fiber (PMX-DHP) which has been utilized as an adjuvant treatment option for patients with severe septic shock.

Methods

66 septic shock patients requiring 2 h direct hemoperfusion therapy PMX-DHP were included. 36 patients of them also received continuous hemodiafiltration (CHDF) after performing PMX-DHP. Circulatory dynamics and levels of inflammatory mediators, namely IL-6, IL-1ra, and PAI-1 were assessed before, immediately after, and 24 h initiation of PMX-DHP.

Results

Mean Arterial Pressure (MAP) rose intentionally by PMX-DHP just after enforcement 24 h later (p < 0.01). Levels of IL-6, IL-1ra, and PAI-1 significantly decreased after PMX-DHP (p < 0.05) and this trend was observed up to 24 h post initiation of PMX-DHP (p < 0.05). IL-6 modulation by PMX-DHP was enhanced with using CHDF and there was a significant correlation between IL-6 and MAP (p < 0.0001). In addition, levels of Il-6 and PAI-1 showed a significant correlation.

Conclusion

Our data showed employing CRRT as cytokine modulators could be an additional therapeutic strategy to improve septic shock outcomes via the crucial role of IL-6 signaling in endothelial dysfunction.

Potential survival benefit and early recovery from organ dysfunction with polymyxin B hemoperfusion: perspectives from a real-world big data analysis and the supporting mechanisms of action

Background

Endotoxin (ET) removal therapy with polymyxin B-immobilized fiber column hemoperfusion (PMX-HP) has been used for the treatment of septic shock. Some observational studies reported clinical benefits, particularly in specific subgroups of patients. However, larger randomized controlled trial results have been disappointing.

Main body

The four studies that revealed the survival benefit of PMX-HP were based on the Japanese Diagnosis Procedure Combination (DPC) national inpatient database (J-DPC study). Nevertheless, one J-DPC study and a randomized controlled trial (RCT) conducted in France evaluated PMX-HP in patients with abdominal septic shock and did not report a significant survival benefit. In both studies, the severity of illness was too low to find substantial significant differences in mortality. The results of the J-DPC studies further suggest that some subpopulations of patients could benefit from PMX-HP. Based on these results, this review revisited prior RCTs and other large-scale studies on PMX-HP. In addition, four J-DPC studies and one large-scale study reported a survival benefit with PMX-HP. A secondary analysis of the EUPHRATES trial, the most recent double-blinded RCT of PMX-HP conducted in North America, suggested a survival benefit in patients with high levels of endotoxemia. In the J-DPC studies and the EUPHRATES trial, ventilator-free days, vasoactive drug-free days, and renal replacement-free days were significantly improved in the PMX-HP groups. These findings suggest that PMX-HP can contribute to early recovery from organ dysfunction. The reduction of supportive care likely provides important health and economic benefits for managing patients with septic shock. Finally, the blood levels of mediators or biomarkers related to respiratory, cardiovascular, and renal dysfunction have been reported to be normalized with PMX-HP.

Conclusions

These results support the biological rationale for the improvement in organ dysfunction observed in the J-DPC studies and other large-scale studies, including the EUPHRATES trial. Real-world evidence from large data sets suggests an appropriate patient population that are likely to benefit from the utility of PMX-HP for septic shock.

Application of oXiris-continuous hemofiltration adsorption in patients with sepsis and septic shock: A single-centre experience in China

oXiris is a new, high-adsorption membrane filter in continuous hemofiltration adsorption to reduce the inflammatory response in sepsis. The investigators retrospectively reviewed patients with sepsis/septic shock who underwent at least one oXiris-treatment from November 2020 to March 2022. The demographic data, baseline levels before treatment, clinical datas, prognosis, and the occurrence of adverse events during treatment were recorded. 90 patients were enrolled in this study. The hemodynamic indices, sequential organ failure assessment score, lactate, inflammatory biomarkers levels were significantly improved at 12 h and 24 h after treatment. Procalcitonin and interleukin-6 reduction post-treatment of oXiris were most pronounced in infection from skin and soft tissue, urinary and abdominal cavity. Logistic regression analysis showed that pre-treatment sequential organ failure assessment score (p = 0.034), percentage decrease in sequential organ failure assessment score (p = 0.004), and age (p = 0.011) were independent risk factors for intensive care unit mortality. In conclusion, oXiris-continuous hemofiltration adsorption may improve hemodynamic indicators, reduce the use of vasoactive drugs, reduce lactate level and infection indicators. Of note, oXiris improve organ function in sepsis, which may result to higher survival rate.

Endotoxin removal therapy with Polymyxin B immobilized fiber column as a COVID-19-bedside strategy protocol for endotoxic shock

Endotoxin -induced sepsis is a leading cause of ICU mortality. From 1994 to the present, PMX-HP has been available as an adjuvant therapy for endotoxin removal and immunomodulation. The efficacy and usefulness of this therapy have been demonstrated for more than a quarter of a century and are partially supported by clinical studies. However, it appears that selected subgroups of patients with endotoxic shock and with appropriate timing could benefit. Endotoxemia may be involved in the pathophysiology of COVID-19, based on enterocyte dysfunction and malabsorptive syndrome. Due to the characteristics of the microbiota, Gram-negative bacteria or their fragments (i.e., endotoxin) may translocate into the systemic circulation leading to inflammatory activation, immune dysfunction, and sepsis. In addition, patients with severe forms of COVID-19 are at risk of superimposed infections. Endotoxemia can arise due to the translocation of Gram-negative bacteria or their fragments from the gut barrier. According to the most updated evidence available from large randomized trials, septic shock patients with MODS > 9 and EA levels ranging from 0.6 to 0.9 are those who may benefit the most from PMX-HP treatment in terms of improvement of survival. As shown in a previous publication, we believe that similarly to the source control, microbiological cultures, and antibiotics administration, EA evaluation at regular intervals, and the targeted use of PMX-HP could be lifesaving and adequate within the golden hour for the diagnosis and treatment of endotoxic shock. In our center, we applied a diagnostic-clinical flowchart also for endotoxic shock related to COVID-19.

Application of Adsorptive Blood Purification Techniques during Cardiopulmonary Bypass in Cardiac Surgery

By reason of surgical demand, the majority of cardiovascular procedures still depend on the use of cardiopulmonary bypass (CPB). Due to the nonphysiological state of CPB, it can cause complex and unpredictable inflammatory response, which may lead to significant morbidity and mortality. Unfortunately, the pharmacological and mechanical strategies that currently exist do not offer significant advantages in controlling inflammatory response and improving patient outcomes. The best strategy to reduce inflammation in CPB is still uncertain. In recent years, adsorptive blood purification techniques (BPTs) have emerged, among which CytoSorb is the latest representative device. Currently, the primary application area of adsorptive BPTs is in the control and treatment of systemic hyperinflammatory states, such as refractory septic shock patients. However, the evidences on efficacy and safety of adsorptive BPTs application during CPB surgery are still inconclusive, so we summarize the relevant evidences here and suggest future potential research areas.

Implications of endotoxins in wound healing: a narrative review

Bacterial toxins are thought to play a role in delayed wound healing in critically colonised and infected wounds. Endotoxins are released from Gram-negative bacteria when they are lysed by host phagocytic cells during an immune response, or by antimicrobial agents, potentially leading to a detrimental effect on the host tissues. Endotoxins can affect all aspects of the wound healing process, leading to delayed healing and contributing to wound chronicity. Release of endotoxins by bacteria can also have serious systemic effects (for example, septic shock) that can lead to high levels of patient mortality. This review summarises the role and implications on wound healing of bacterial endotoxins, describing the impact of endotoxins on the various phases of the wound healing response. There is a paucity of in vivo/clinical evidence linking endotoxins attributed to a wound (via antibiotic treatment) or their release from infecting bacteria with parameters of delayed wound healing. Future work should investigate if this link is apparent and determine the mechanism(s) by which such detrimental effects occur, offering an opportunity to identify possible treatment pathways. This paper describes the phenomenon of antimicrobial-induced endotoxin release and summarises the use of wound dressings to reduce wound bioburden without inducing microbial death and subsequent release of endotoxins, thus limiting their detrimental effects.

Adsorption-Based Detoxification of Endotoxins by Porous Flexible Organic Frameworks

Bacterial lipopolysaccharides (LPS, endotoxins) cause sepsis that is responsible for a huge amount of mortality globally. However, their neutralization or detoxification remains an unmet medical need. We envisaged that cationic organic frameworks with persistent hydrophobic porosity may adsorb and thus neutralize LPS through a combination of cooperative ion-pairing electrostatic attraction and hydrophobicity. We here report the preparation of two water-soluble flexible organic frameworks (FOF-1 and FOF-2) from tetratopic and ditopic precursors through quantitative formation of hydrazone bonds at room temperature. The two FOFs are revealed to possess hydrodynamic diameters, which range from 20 to 120 nm, depending on the concentrations. Dynamic light scattering and isothermal titration calorimetric and chromogenic limulus amebocyte lysate experiments indicate that both frameworks are able to adsorb and thus reduce the concentration of free LPS molecules in aqueous solution, whereas cytokine inhibition experiments with RAW264.7 support that this adsorption can significantly decrease the toxicity of LPS. In vivo experiments with mice (five males per group) show that the injection of FOF-1 at a dose of 0.6 mg/kg realizes the survival of all of the mice administrated with LPS of the d-galactosamine (d-Gal)-sensitized absolute lethal dose (LD₁₀₀, 0.05 mg/kg), whereas its maximum tolerated dose for mice is determined to be 10 mg/kg. These findings provide a new promising sequestration strategy for the development of porous agents for the neutralization of LPS.

Renal Replacement Techniques in Septic Shock

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to an infection; it carries a risk for mortality, considerably exceeding that of a mere infection. Sepsis is the leading cause for acute kidney injury (AKI) and the requirement for renal replacement therapy (RRT) in intensive care unit (ICU) patients. Almost every second critically ill patient with sepsis will develop AKI. In septic shock, the dysregulated host response to infectious pathogens leads to a cytokine storm with uncontrolled production and release of humoral proinflammatory mediators that evoke cellular toxicity and promote the development of organ dysfunction and increased mortality. In addition to treating AKI, RRT techniques can be employed for extracorporeal adsorption of inflammatory mediators using specifically developed adsorption membranes, hemoperfusion sorbent cartridges or columns; these techniques are intended to decrease the level and early deleterious effects of circulating proinflammatory cytokines and endotoxins during the first hours and days of septic shock treatment, in order to improve patient outcomes. Several methods and devices, such as high cut-off membranes, the Oxiris®-AN69 membrane, CytoSorb® and HA380 cytokine hemoadsorption, polymyxin B endotoxin adsorption, and plasmapheresis have been examined in small study series or are under evaluation as ways of improving patient outcomes in septic shock. However, to date, the data on actual outcome benefits have remained controversial, as discussed in this review.

Targeting Cytokines, Pathogen-Associated Molecular Patterns, and Damage-Associated Molecular Patterns in Sepsis via Blood Purification

Sepsis is characterized by a dysregulated immune response to infections that causes life-threatening organ dysfunction and even death. When infections occur, bacterial cell wall components (endotoxin or lipopolysaccharide), known as pathogen-associated molecular patterns, bind to pattern recognition receptors, such as toll-like receptors, to initiate an inflammatory response for pathogen elimination. However, strong activation of the immune system leads to cellular dysfunction and ultimately organ failure. Damage-associated molecular patterns (DAMPs), which are released by injured host cells, are well-recognized triggers that result in the elevation of inflammatory cytokine levels. A cytokine storm is thus amplified and sustained in this vicious cycle. Interestingly, during sepsis, neutrophils transition from powerful antimicrobial protectors into dangerous mediators of tissue injury and organ dysfunction. Thus, the concept of blood purification has evolved to include inflammatory cells and mediators. In this review, we summarize recent advances in knowledge regarding the role of lipopolysaccharides, cytokines, DAMPs, and neutrophils in the pathogenesis of sepsis. Additionally, we discuss the potential of blood purification, especially the adsorption technology, for removing immune cells and molecular mediators, thereby serving as a therapeutic strategy against sepsis. Finally, we describe the concept of our immune-modulating blood purification system.