Lipopolysaccharide-Induced Hemolysis Is Abolished by Inhibition of Thrombin Generation but Not Inhibition of Platelet Aggregation

Engineered Bacterial Outer Membrane Vesicles-Based Doxorubicin and CD47-siRNA Co-Delivery Nanoplatform Overcomes Immune Resistance to Potentiate the Immunotherapy of Glioblastoma

Apart from the blood-brain barrier (BBB), the efficacy of immunotherapy for glioblastoma (GBM) is limited by the presence of intrinsic and adaptive immune resistance, implying that co-delivery of various immunotherapeutic agents or simultaneous regulation of different cells is urgently needed. Bacterial outer membrane vesicles (OMVs) offer a unique advantage in the treatment of GBM, owing to their multifunctional properties as carriers and immune adjuvants and their ability to cross the BBB. However, traditional OMVs can lead to toxic side effects and disruption of tight junctions in the BBB. Therefore, to enhance the in vivo safety and targeting capability of OMVs, we introduced engineered OMVs to reduce toxicity and further constructed a modularly assembled nanoplatform by performing simple peptide modifications. This nanoplatform demonstrates satisfactory biosafety and is able to continuously cross the BBB and target GBM with the assistance of Angiopep-2. Subsequently, immunogenic substances on OMVs, along with carried small-interfering RNA (siRNA) and doxorubicin, can promote and enhance the reprogramming and phagocytic abilities of macrophages and microglia, respectively, and increase the immunogenicity of GBM, ultimately overcoming GBM immune resistance to enhance the efficacy of immunotherapy. This OMVs-based nanoplatform provides a new paradigm and insights into the development of immunotherapy for GBM.

PCT, IL-6, and IL-10 facilitate early diagnosis and pathogen classifications in bloodstream infection

BACKGROUND

In the diagnosis of bloodstream infection (BSI), various inflammatory markers such as C-reactive protein (CRP), procalcitonin (PCT), interleukins (IL), white blood cell count (WBC), neutrophil percentage (NE%), platelet count (PLT), and erythrocyte sedimentation rate (ESR) have been extensively utilized. However, their specific roles in distinguishing BSI from local bacterial infection (LBI) and in classifying BSI pathogens remain uncertain.

METHODS

A historical cohort study was conducted, involving the enrollment of 505 patients with BSI and 102 patients with LBI. To validate the reliability of the clinical data obtained from this cohort, mouse models of BSI were utilized.

RESULTS

Our findings revealed that patients with BSI had significantly higher levels of inflammatory markers, including CRP, PCT, IL-6, IL-10, WBC, NE%, and ESR, compared to those with LBI (p < 0.05). The receiver operating characteristic (ROC) curve analysis demonstrated that CRP, PCT, IL-6, IL-10, ESR and NE% exhibited excellent diagnostic efficacy for BSI. Additionally, we observed significant differences in CRP, PCT, IL-6, and IL-10 levels between patients with BSI caused by Gram-positive bacteria (GP-BSI) and Gram-negative bacteria (GN-BSI), but no significant variations were found among specific bacterial species. Furthermore, our study also found that CRP, PCT, and IL-10 have good discriminatory ability for vancomycin-resistant Enterococcus (VRE), but they show no significant diagnostic efficacy for other multidrug-resistant organisms (MDROs) such as carbapenem-resistant Enterobacteriaceae (CRE), carbapenem-resistant Pseudomonas aeruginosa (CRPA), and methicillin-resistant Staphylococcus aureus (MRSA). In our mouse model experiments, we observed a remarkable increase in PCT, IL-6, and IL-10 levels in mice with GN-BSI compared to those with GP-BSI.

CONCLUSION

Our study has confirmed that PCT, IL-6, and IL-10 are efficient biomarkers for distinguishing between BSI and LBI. Furthermore, they can be utilized to classify BSI pathogens and differentiate between VRE and vancomycin-susceptible Enterococcus. These findings are extremely valuable for clinicians as they enable timely initiation of empiric antibiotic therapies and ultimately lead to improved clinical outcomes for patients with BSI.

Novel aspects of sepsis pathophysiology: NETs, plasma glycoproteins, endotheliopathy and COVID-19

In 2016, sepsis was newly defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis remains one of the crucial medical problems to be solved worldwide. Although the world health organization has made sepsis a global health priority, there remain no specific and effective therapy for sepsis so far. Indeed, over the previous decades almost all attempts to develop novel drugs have failed. This may be partly ascribable to the multifactorial complexity of the septic cascade and the resultant difficulties of identifying drug targets. In addition, there might still be missing links among dysregulated host responses in vital organs. In this review article, recent advances in understanding of the complex pathophysiology of sepsis are summarized, with a focus on neutrophil extracellular traps (NETs), the significant role of NETs in thrombosis/embolism, and the functional roles of plasma proteins, histidine-rich glycoprotein (HRG) and inter-alpha-inhibitor proteins (IAIPs). The specific plasma proteins that are markedly decreased in the acute phase of sepsis may play important roles in the regulation of blood cells, vascular endothelial cells and coagulation. The accumulating evidence may provide us with insights into a novel aspect of the pathophysiology of sepsis and septic ARDS, including that in COVID-19.

Biomimetic Lipopolysaccharide-Free Bacterial Outer Membrane-Functionalized Nanoparticles for Brain-Targeted Drug Delivery

The blood-brain barrier (BBB) severely blocks the intracranial accumulation of most systemic drugs. Inspired by the contribution of the bacterial outer membrane to Escherichia coli K1 (EC-K1) binding to and invasion of BBB endothelial cells in bacterial meningitis, utilization of the BBB invasion ability of the EC-K1 outer membrane for brain-targeted drug delivery and construction of a biomimetic self-assembled nanoparticle with a surface featuring a lipopolysaccharide-free EC-K1 outer membrane are proposed. BBB penetration of biomimetic nanoparticles is demonstrated to occur through the transcellular vesicle transport pathway, which is at least partially dependent on internalization, endosomal escape, and transcytosis mediated by the interactions between outer membrane protein A and gp96 on BBB endothelial cells. This biomimetic nanoengineering strategy endows the loaded drugs with prolonged circulation, intracranial interstitial distribution, and extremely high biocompatibility. Based on the critical roles of gp96 in cancer biology, this strategy reveals enormous potential for delivering therapeutics to treat gp96-overexpressing intracranial malignancies.

Simvastatin Prevents Liver Microthrombosis and Sepsis Induced Coagulopathy in a Rat Model of Endotoxemia

Background: Endotoxemia causes endothelial dysfunction and microthrombosis, which are pathogenic mechanisms of coagulopathy and organ failure during sepsis. Simvastatin has potential anti-thrombotic effects on liver endothelial cells. We investigated the hemostatic changes induced by lipopolysaccharide (LPS) and explored the protective effects of simvastatin against liver vascular microthrombosis. Methods and results: We compared male Wistar rats exposed to LPS (5 mg/kg one i.p. dose) or saline in two experimental protocols—placebo (vehicle) and simvastatin (25 mg/kg die, orally, for 3 days before LPS). Morphological studies were performed by light- and electron-microscopy analyses to show intravascular fibrin deposition, vascular endothelial structure and liver damage. Peripheral- and organ-hemostatic profiles were analyzed using whole blood viscoelastometry by ROTEM, liver biopsy and western-blot/immunohistochemistry of thrombomodulin (TM), as well as immunohistochemistry of the von Willebrand factor (VWF). LPS-induced fibrin deposition and liver vascular microthrombosis were combined with a loss of sinusoidal endothelial TM expression and VWF-release. These changes were associated with parenchymal eosinophilia and necrosis. ROTEM analyses displayed hypo-coagulability in the peripheral blood that correlated with the degree of intrahepatic fibrin deposition (p < 0.05). Simvastatin prevented LPS-induced fibrin deposition by preserving TM expression in sinusoidal cells and completely reverted the peripheral hypo-coagulability caused by endotoxemia. These changes were associated with a significant reduction of liver cell necrosis without any effect on eosinophilia. Conclusions: Simvastatin preserves the antithrombotic properties of sinusoidal endothelial cells disrupted by LPS, deserving pharmacological properties to contrast sepsis-associated coagulopathy and hepatic failure elicited by endotoxemia

Protective Mechanism of the Selective Vasopressin V1A Receptor Agonist Selepressin against Endothelial Barrier Dysfunction

Sepsis and septic shock are among the most common causes of death in the intensive care unit; advanced therapeutic approaches are thus urgently needed. Vascular hyperpermeability represents a major manifestation of severe sepsis and is responsible for the ensuing organ dysfunction and failure. Vasopressin V1A receptor (V1AR) agonists have shown promise in the treatment of sepsis, increasing blood pressure, and reducing vascular hyperpermeability. The effects of the selective V1AR-selective agonist selepressin have been investigated in an in vitro model of thrombin-, vascular endothelial growth factor-, angiopoietin 2-, and lipopolysaccharide (LPS)-induced pulmonary microvascular endothelial hyperpermeability. Results suggest that selepressin counteracts the effects of all four endothelial barrier disruptors in a concentration-dependent manner, as reflected in real-time measurements of vascular permeability by means of transendothelial electrical resistance. Further, selepressin protected the barrier integrity against the LPS-mediated corruption of the endothelial monolayer integrity, as captured by VE-cadherin and actin staining. The protective effects of selepressin were abolished by silencing of the vasopressin V1AR, as well as by atosiban, an antagonist of the human V1AR. p53 appears to be involved in mediating these palliative effects, since selepressin strongly induced its expression levels, suppressed the inflammatory RhoA/myosin light chain2 pathway, and triggered the barrier-protective effects of the GTPase Rac1. We conclude that V1AR-selective agonists, such as selepressin, may prove useful in the improvement of endothelial barrier function in the management of severe sepsis. SIGNIFICANCE STATEMENT: A cardinal sign of sepsis, a serious disease with significant mortality and no specific treatment, is pulmonary endothelial barrier dysfunction that leads to pulmonary edema. Here, we present evidence that in cultured human lung microvascular endothelial cells, the synthetic, selective vasopressin V1A receptor agonist selepressin protects against endothelial barrier dysfunction caused by four different edemogenic agents, suggesting a potential role of selepressin in the clinical management of sepsis.

Lactoferrin-Loaded PEG/PLA Block Copolymer Targeted With Anti-Transferrin Receptor Antibodies for Alzheimer Disease

Last few years, struggles have been reported to develop the nanovesicles for drug delivery via the brain-blood barrier (BBB). Novel drugs, for instance, iAβ5, are efficient to inhibit the aggregates connected to the treatment of Alzheimer disease and are being evaluated, but most of the reports reflect some drawbacks of the drugs to reach the brain in preferred concentrations owing to the less BBB penetrability of the surface dimensions. In this report, we designed and developed a new approach to enhance the transport of drug via BBB, constructed with lactoferrin (Lf)-coated polyethylene glycol-polylactide nanoparticles (Lf-PPN) with superficial monoclonal antibody-functionalized antitransferrin receptor and anti-Aβ to deliver the iAβ5 hooked on the brain. The porcine brain capillary endothelial cells were utilized as BBB typically to examine the framework efficacy and toxicity. The cellular uptake of the immuno-nanoparticles with measured conveyance of the iAβ5 peptide was significantly enhanced and associated with Lf-PPN without monoclonal antibody functionalizations.