Diagnostic potential of endotoxin scattering photometry for sepsis and septic shock

Broad-Spectrum Clearance of Lipopolysaccharides from Blood Based on a Hemocompatible Dihistidine Polymer

Blood infection can release toxic bacterial lipopolysaccharides (LPSs) into bloodstream, trigger a series of inflammatory reactions, and eventually lead to multiple organ dysfunction, irreversible shock, and even death, which seriously threatens human life and health. Herein, a functional block copolymer with excellent hemocompatibility is proposed to enable broad-spectrum clearance of LPSs from whole blood blindly before pathogen identification, facilitating timely rescue from sepsis. A dipeptide ligand of histidine-histidine (HH) was designed as the LPS binding unit, and poly[(trimethylamine N-oxide)-co-(histidine-histidine)], a functional block copolymer combining the LPS ligand of HH and a zwitterionic antifouling unit of trimethylamine N-oxide (TMAO), was then designed by reversible addition-fragmentation chain transfer (RAFT) polymerization. The functional polymer achieved effective clearance of LPSs from solutions and whole blood in a broad-spectrum manner and had good antifouling and anti-interference properties and hemocompatibility. The proposed functional dihistidine polymer provides a novel strategy for achieving broad-spectrum clearance of LPSs, with potential applications in clinical blood purification.

Use of Organ Dysfunction as a Primary Outcome Variable Following Cecal Ligation and Puncture: Recommendations for Future Studies

Outcomes variables for research on sepsis have centered on mortality and changes in the host immune response. However, a recent task force (Sepsis-3) revised the definition of sepsis to "life-threatening organ dysfunction caused by a dysregulated host response to infection." This new definition suggests that human studies should focus on organ dysfunction. The appropriate criteria for organ dysfunction in either human sepsis or animal models are, however, poorly delineated, limiting the potential for translation. Further, in many systems, the difference between "dysfunction" and "injury" may not be clear. In this review, we identify criteria for organ dysfunction and/or injury in human sepsis and in rodents subjected to cecal ligation and puncture (CLP), the most commonly used animal model of sepsis. We further examine instances where overlap between human sepsis and CLP is sufficient to identify translational endpoints. Additional verification may demonstrate that these endpoints are applicable to other animals and to other sepsis models, for example, pneumonia. We believe that the use of these proposed measures of organ dysfunction will facilitate mechanistic studies on the pathobiology of sepsis and enhance our ability to develop animal model platforms to evaluate therapeutic approaches to human sepsis.

The Prognostic Value of Presepsin for Sepsis in Abdominal Surgery: A Prospective Study

INTRODUCTION

Rapid diagnosis accompanied by appropriate treatment is essential in the therapy of sepsis. However, there is no blood marker available, which reliably predicts sepsis and associated mortality. Therefore, the aim of the present study was to evaluate presepsin and endotoxin in comparison with established blood markers in patients undergoing emergency visceral surgery for abdominal infection.

PATIENTS AND METHODS

This prospective study included 31 patients with abdominal infection undergoing emergency surgery between March and August 2014. The Sepsis-2 and Sepsis-3 definitions of sepsis were used. Blood markers (presepsin, endotoxin, C-reactive protein, procalcitonin (PCT), interleukin 6 (IL-6), white blood count) were analyzed preoperatively and correlated with the clinical course and mortality. Additionally, a combination of the three markers, which performed best, was tested.

RESULTS

Twenty patients (64.5%) in the analyzed cohort developed sepsis from an abdominal focus according to the latest sepsis definition. Out of the analyzed blood markers, presepsin exhibited the highest area under the curve, sensitivity, and specificity for the prediction of the development of sepsis. Moreover, presepsin had the highest predictive value for mortality as opposed to both endotoxin and previously established blood markers (i.e., PCT, IL-6). The multimarker approach, which included PCT, IL-6, and presepsin, showed no additional predictive value over presepsin alone.

CONCLUSION

The present study suggests that presepsin is a novel predictor of sepsis and mortality from sepsis in patients undergoing surgery for intra-abdominal infections. The findings of the present study should be validated in a larger cohort.

Outstanding Contributions of LAL Technology to Pharmaceutical and Medical Science: Review of Methods, Progress, Challenges, and Future Perspectives in Early Detection and Management of Bacterial Infections and Invasive Fungal Diseases

The blue blood of the horseshoe crab is a natural, irreplaceable, and precious resource that is highly valued by the biomedical industry. The Limulus amebocyte lysate (LAL) obtained from horseshoe crab blood cells functions as a surprisingly sophisticated sensing system that allows for the extremely sensitive detection of bacterial and fungal cell-wall components. Notably, LAL tests have markedly contributed to the quality control of pharmaceutical drugs and medical devices as successful alternatives to the rabbit pyrogen test. Furthermore, LAL-based endotoxin and (1→3)-β-D-glucan (β-glucan) assay techniques are expected to have optimal use as effective biomarkers, serving as adjuncts in the diagnosis of bacterial sepsis and fungal infections. The innovative β-glucan assay has substantially contributed to the early diagnosis and management of invasive fungal diseases; however, the clinical significance of the endotoxin assay remains unclear and is challenging to elucidate. Many obstacles need to be overcome to enhance the analytical sensitivity and clinical performance of the LAL assay in detecting circulating levels of endotoxin in human blood. Additionally, there are complex interactions between endotoxin molecules and blood components that are attributable to the unique physicochemical properties of lipopolysaccharide (LPS). In this regard, while exploring the potential of new LPS-sensing technologies, a novel platform for the ultrasensitive detection of blood endotoxin will enable a reappraisal of the LAL assay for the highly sensitive and reliable detection of endotoxemia.

The Elevation in Preoperative Procalcitonin Is Associated with a Poor Prognosis for Patients Undergoing Resection for Colorectal Cancer

BACKGROUND

Procalcitonin (PCT) is a well-known marker for bacterial infection; however, the clinical significance of PCT in the long-term prognosis after colorectal cancer (CRC) surgery remains unclear.

METHODS

This is a retrospective review of 277 patients that underwent CRC surgery to investigate the relationship between preoperative PCT, clinicopathological condition, cancer-specific overall survival (OS), and relapse-free survival (RFS).

RESULTS

Median follow-up interval was 5.0 years in all patients. Thirty-six patients developed recurrence, and 46 patients died due to recurrences or metastases of CRC. Preoperative PCT levels were highest in Stage IV patients. The cancer-specific OS in patients with Stage IV/PCT ≤0.05 ng/mL was significantly higher than those with Stage IV/PCT >0.05 ng/mL (3 years survival; 42.3 vs. 14.3%, p = 0.0413). On multivariate analysis, gender, TNM classification, and PCT were identified as significant risk factors for cancer-specific OS in patients with Stage I-III CRC. The cancer-specific OS rate of these patients with PCT ≥0.08 ng/mL, compared with PCT <0.08 ng/mL, was significantly decreased (5 years survival; 59.1 vs. 92.7%, p < 0.0001). TNM classification was finally identified as an independent risk factor for cancer-specific RFS in these patients by multivariate analysis.

CONCLUSION

High preoperative PCT values in CRC patients appeared to be associated with poor OS but not RFS following surgical treatments.

Anti-endotoxin Properties of Polymyxin B-immobilized Fibers

Polymyxin B is an antibiotic that shows strong bactericidal activity against Gram-negative bacteria, by binding to and inactivating endotoxin. Systemic administration of polymyxin B in humans is restricted because of its nephrotoxicity and neurotoxicity, and this compound was therefore considered a strong candidate ligand for the extracorporeal selective adsorption of circulating endotoxin in the blood. Toraymyxin® is a direct hemoperfusion column that uses polymyxin B attached to an insoluble carrier to bind endotoxin in the blood. In 1994, the Japanese National Health Insurance system approved the use of Toraymyxin for the treatment of endotoxemia and septic shock.In this chapter, we will review the development, clinical use, and efficacy of Toraymyxin, examine the structure of the Toraymyxin column, and comment on the current position of Toraymyxin in the treatment of severe sepsis and septic shock. We will also highlight some potential new applications of Toraymyxin for pulmonary diseases.

Endotoxin adsorption: Direct hemoperfusion with the polymyxin B-immobilized fiber column (PMX)

Toraymyxin^® is a medical device developed to adsorb circulating endotoxins in the blood using direct hemoperfusion therapy for patients with septic shock. In 1994, the Japanese National Health Insurance system approved the use of Toraymyxin for the treatment of endotoxemia and septic shock. Since then, Toraymyxin has been safely used in more than 100,000 cases in emergency and intensive care units in Japan. Toraymyxin is currently available for use in the clinical setting in 14 countries worldwide. In this study, we reviewed and introduced the development, clinical use, and efficacy of Toraymyxin and commented on its anticoagulant use and cartridge clotting issue in the treatment of severe sepsis and septic shock. We also highlighted potential new applications of Toraymyxin for longer duration therapy and pulmonary diseases.

A comparative study of blood endotoxin detection in haemodialysis patients

BACKGROUND

Endotoxemia is commonly reported in patients receiving haemodialysis and implicated in the pathogenesis of systemic inflammation. The Limulus Amoebocyte Lysate (LAL) assay is the most commonly used blood endotoxin detection assay. Two kinetic variations of the assay are commercially available - the turbidimetric and chromogenic assay, it is unknown which assay is superior for endotoxin detection in uremic patients. Selection of the optimum LAL technique for endotoxin detection in haemodialysis patients is important to further understanding of the sequela of endotoxemia and development of endotoxin-lowering strategies in this population.

METHOD

A turbidimetric and chromogenic LAL assay from the same manufacturer were directly compared. We investigated the ability of both LAL assays to detect endotoxin in uremic plasma. Plasma samples from haemodialysis patients and healthy controls were spiked with endotoxin and percentage spike recovery for the chromogenic and turbidimetric assay was determined. Assay accuracy and precision were compared between both LAL assays.

RESULTS

The turbidimetric assay had greater accuracy than the chromogenic assay. Spike recovery was 113.8 % vs. 53.8 % for the turbidimetric and chromogenic assay respectively. Assay bias was higher in the chromogenic assay (-0.384EU/mL vs. 0.011EU/mL). The turbidimetric assay demonstrated greater precision compared to the chromogenic assay. Coefficient of variation ranged from 4.5 to 24.1 % for the turbidimetric assay and 25.8-26.5 % for the chromogenic assay.

CONCLUSION

The study findings suggest that the kinetic turbidimetric LAL assay has greater accuracy and precision than the chromogenic assay and is the optimum LAL technique for endotoxin detection in haemodialysis patients, though these findings should be verified using LAL reagents from other sources.

Endotoxemia in end-stage kidney disease

Chronic unexplained inflammation remains a prevalent and clinically significant problem for patients with end-stage kidney disease (ESKD), especially in the dialysis population. The causes of persistent inflammation are likely to be multifactorial, but the underlying mechanisms remain to be elucidated. Endotoxins are reported to play a significant role in the pathogenesis of inflammation in patients with ESKD. However, blood endotoxin measurement with the Limulus amoebocyte lysate (LAL) assay is difficult with current detection systems. The reported degree and prevalence of endotoxemia varies in the literature. There are questions as to whether endotoxemia is truly present; whether the varied findings are due to methodological issues with the LAL assay and whether any endotoxemia that might be present plays a role in chronic inflammation frequently observed in ESKD patients. This review will discuss the challenges of accurate blood endotoxin detection, the potential source of blood endotoxins, and the significance of endotoxemia to patient with ESKD.