Association of type II secretory phospholipase A2 and surfactant protein D with the pulmonary oxygenation potential in patients with septic shock during polymyxin-B immobilized fiber-direct hemoperfusion

Inhibition of sPLA2 enzyme activity by cell-permeable antioxidant EUK-8 and downregulation of p38, Akt, and p65 signals induced by sPLA2 in inflammatory mouse paw edema model

The arachidonic acid (AA) metabolic pathway, plays a vital role in the production of eicosanoids by the action of pro-inflammatory secretory phospholipase A₂ (PLA₂ ). Release of eicosanoids is known to be involved in many inflammatory diseases. Identification of the inhibitory molecules of this AA pathway enzyme along with the regulation of intracellular signaling cascades may be a finer choice to develop as a powerful anti-inflammatory drug. In this regard, we have screened few cell-permeable antioxidant molecules Tempo, Mito-TEMPO, N,N'-Bis(salicylideneamino)ethane-manganese(II) (EUK)-134, and EUK-8 against pro-inflammatory sPLA₂ s. Among these, we found EUK-8 is a potent inhibitor with its IC₅₀ value ranges 0.7-2.0 µM for sPLA₂ s isolated from different sources. Furthermore, docking studies confirm the strong binding of EUK-8 towards sPLA₂ . In vivo effect of EUK-8 was studied in HSF-sPLA₂ -induced edema in mouse paw model. In addition to neutralizing the edema, EUK-8 significantly reduces the phosphorylation level of inflammatory proteins such as p38 member of MAPK pathway, Akt, and p65 along with the suppression of pro-inflammatory cytokine (interleukin-6) and chemokine (CXCL1) in edematous tissue. This shows that EUK-8 not only inhibits the sPLA₂ activity, it also plays an important role in the regulation of sPLA₂ -induced cell signaling cascades. Apart from the sPLA₂ inhibition, we also examine the regulatory actions of EUK-8 with other downstream enzymes of AA pathway such as 5-LOX assay in human polymorphonuclear leukocytes (PMNs) and COX-2 expression in carrageenan-λ induced paw edema. Here EUK-8 significantly inhibits 5-LOX enzyme activity and downregulates COX-2 expression. These data indicate that EUK-8 found to be a promising multitargeted inhibitory molecule toward inflammatory pathway. In conclusion, mitochondrial targeted antioxidant EUK-8 is not only the powerful antioxidant, also a potent anti-inflammatory molecule and may be a choice of molecule for pharmacological applications.

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.

Molecular mechanisms in septic shock (Review)

Sepsis is a clinical syndrome defined by the presence of infection and systemic inflammatory response to infection and results from a complex interaction between the host and infectious agents. It is characterized by the activation of multiple inflammatory pathways, with an increased risk of mortality. The incidence of sepsis has been on an ever-increasing pathway in recent years. Sepsis can be induced by several clinical situations that predispose to its occurrence: malignant tumors, organ transplantation, AIDS, radiation therapy, burns, sores, polytrauma, diabetes mellitus, hepatic failure, renal failure, malnutrition, catheters or different invasive devices, and urinary catheters. The microorganisms involved in the pathogenesis of sepsis are Gram-positive cocci (Staphylococci, Streptococci) and Gram-negative bacilli (Klebsiella, Pseudomonas aeruginosa, E. coli), fungi (Candida), parasites, and viruses. Among mechanisms involved in septic shock production, two pathological phenomena appear: the profound decompensation of circulation and metabolic disturbances that evolve towards an irreversible state. The intimate mechanism of shock involves the activation of monocytes, macrophages and neutrophils by lipopolysaccharides of Gram-negative bacteria. The microvascular bed is directly involved in the etiopathogenesis of disorders of acute inflammatory states associated with or without sepsis. A better comprehension of sepsis pathophysiology, especially the molecular mechanisms of septic shock, allows for new therapeutic perspectives.

Clinical Effects of Polymyxin B Hemoperfusion in Patients With Septic Shock Caused by Urinary Tract Infection

Direct hemoperfusion with polymyxin B-immobilized fiber (PMX-DHP) has been widely used for severe sepsis and septic shock. However, data are limited regarding the clinical experience and efficacy of PMX-DHP for septic shock resulting from urinary tract infection (UTI). At our institution, 15 patients with septic shock resulting from a UTI received PMX-DHP from January 2013 to July 2017. The cause of the urosepsis was mainly obstructive pyelonephritis secondary to ureterolithiasis or neurogenic bladder. Average Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores were 25.9 ± 4.3 and 10.5 ± 2.2, respectively. If patients were still hypotensive after initial resuscitation, we began PMX-DHP. Mean arterial pressure increased significantly from 58.3 ± 9.6 mm Hg to 93.6 ± 14.8 mm Hg just after PMX-DHP and to 94.7 ± 16.9 mm Hg (P < 0.0001) 24 h after the treatment. Catecholamine index decreased significantly from 20.7 ± 11.3 to 9.3 ± 13.5 (P = 0.0001) 24 h after the treatment. Of 15 patients, 14 (93.3%) had survived 28 days after admission. Our results suggest a possible role for PMX-DHP in the rapid stabilization of hemodynamics in patients with septic shock with an underlying UTI. These patients may be good candidates for PMX-DHP.

C-terminal fragment of agrin (CAF) levels predict acute kidney injury after acute myocardial infarction

Background

Patients with acute myocardial infarction are at high risk for acute kidney injury. Novel biomarkers that can predict acute kidney injury in AMI may allow timely interventions. C-terminal fragment of agrin (CAF), a proteoglycan of the glomerular and tubular basement membrane, have been recently associated with rapid renal function deterioration and proximal tubular dysfunction. It is unknown whether elevated CAF levels may serve as a novel AKI biomarker in patients presenting with AMI.

Methods

In 436 persons enrolled in a multicenter prospective observational cohort study of patients with acute myocardial infarction, we measured plasma and urine levels of several kidney injury biomarkers including CAF, neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18) and cystatin-C.The relationship between biomarker levels at baseline and the development of AKI and long-term mortality were analyzed after adjustment for demographic and clinical variables.

Results

AKI incidence was up to 15% during hospitalization. The predictive accuracy for AKI of urinary CAF was similar to NGAL and superior to other tested kidney injury biomarkers. In a multivariate model that included all possible confounding variables only urinary CAF continued to be an independent marker for AKI (OR 1.35 95%CI 1.05 -1.74). During the 2 years follow-up, only plasma CAF levels remained a significant independent predictor of mortality (OR 2.5 95%CI 1.02-6.2; P = 0.04).

Conclusions

Elevated CAF levels are associated with AKI in patients with acute myocardial infarction. Our study provides preliminary evidence that CAF levels may predict AKI and mortality after AMI in low risk patients with relative preserved kidney function at baseline.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0611-9) contains supplementary material, which is available to authorized users.