scholarly journals Visualizing the Potential Impairment of Polymyxin B to Central Nervous System Through MR Susceptibility-Weighted Imaging

2021 ◽  
Vol 12 ◽  
Author(s):  
Ni Zhang ◽  
Lichong Zhu ◽  
Qiuhong Ouyang ◽  
Saisai Yue ◽  
Yichun Huang ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Polymyxin B ◽  
Susceptibility Weighted Imaging ◽  
Gram Negative Bacteria ◽  
Severe Toxicity ◽  
Gram Negative ◽  
The Impact

Polymyxin B (PMB) exert bactericidal effects on the cell wall of Gram-negative bacteria, leading to changes in the permeability of the cytoplasmic membrane and resulting in cell death, which is sensitive to the multi-resistant Gram-negative bacteria. However, the severe toxicity and adverse side effects largely hamper the clinical application of PMB. Although the molecular pathology of PMB neurotoxicity has been adequately studied at the cellular and molecular level. However, the impact of PMB on the physiological states of central nervous system in vivo may be quite different from that in vitro, which need to be further studied. Therefore, in the current study, the biocompatible ultra-uniform Fe3O4 nanoparticles were employed for noninvasively in vivo visualizing the potential impairment of PMB to the central nervous system. Systematic studies clearly reveal that the prepared Fe3O4 nanoparticles can serve as an appropriate magnetic resonance contrast agent with high transverse relaxivity and outstanding biosafety, which thus enables the following in vivo susceptibility-weighted imaging (SWI) studies on the PMB-treated mice models. As a result, it is first found that the blood-brain barrier (BBB) of mice may be impaired by successive PMB administration, displaying by the discrete punctate SWI signals distributed asymmetrically across brain regions in brain parenchyma. This result may pave a noninvasive approach for in-depth studies of PMB medication strategy, monitoring the BBB changes during PMB treatment, and even assessing the risk after PMB successive medication in multidrug-resistant Gram-negative bacterial infected patients from the perspective of medical imaging.

scholarly journals Repurposing of the Fasciolicide Triclabendazole to Treat Infections Caused by Staphylococcus spp. and Vancomycin-Resistant Enterococci

2021 ◽  
Vol 9 (8) ◽  
pp. 1697
Author(s):  
Hongfei Pi ◽  
Abiodun D. Ogunniyi ◽  
Bhumi Savaliya ◽  
Hang Thi Nguyen ◽  
Stephen W. Page ◽  
...  
Keyword(s):  
Fasciola Hepatica ◽  
Bacterial Pathogens ◽  
Oral Treatment ◽  
Polymyxin B ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Vancomycin Resistant Enterococci ◽  
Vancomycin Resistant

One approach to combat the increasing incidence of multidrug-resistant (MDR) bacterial pathogens involves repurposing existing compounds with known safety and development pathways as new antibacterial classes with potentially novel mechanisms of action. Here, triclabendazole (TCBZ), a drug originally developed to treat Fasciola hepatica (liver fluke) in sheep and cattle, and later in humans, was evaluated as an antibacterial alone or in combination with sub-inhibitory concentrations of polymyxin B (PMB) against clinical isolates and reference strains of key Gram-positive and Gram-negative bacteria. We show for the first time that in vitro, TCBZ selectively kills methicillin-sensitive and methicillin-resistant Staphylococcus aureus and Staphylococcus pseudintermedius at a minimum inhibitory concentration (MIC) range of 2–4 µg/mL, and vancomycin-resistant enterococci at a MIC range of 4–8 µg/mL. TCBZ also inhibited key Gram-negative bacteria in the presence of sub-inhibitory concentrations of PMB, returning MIC90 values of 1 µg/mL for Escherichia coli, 8 µg/mL for Klebsiella pneumoniae, 2 µg/mL for Acinetobacter baumannii and 4 µg/mL for Pseudomonasaeruginosa. Interestingly, TCBZ was found to be bacteriostatic against intracellular S. aureus but bactericidal against intracellular S. pseudintermedius. Additionally, TCBZ’s favourable pharmacokinetic (PK) and pharmacodynamic (PD) profile was further explored by in vivo safety and efficacy studies using a bioluminescent mouse model of S. aureus sepsis. We show that repeated four-hourly oral treatment of mice with 50 mg/kg TCBZ after systemic S. aureus challenge resulted in a significant reduction in S. aureus populations in the blood to 18 h post-infection (compared to untreated mice) but did not clear the bacterial infection from the bloodstream, consistent with in vivo bacteriostatic activity. These results indicate that additional pharmaceutical development of TCBZ may enhance its PK/PD, allowing it to be an appropriate candidate for the treatment of serious MDR bacterial pathogens.

scholarly journals In Vitro and In Vivo Evaluation of 99mTc-Polymyxin B for Specific Targeting of Gram-Bacteria

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 232
Author(s):  
Sveva Auletta ◽  
Filippo Galli ◽  
Michela Varani ◽  
Giuseppe Campagna ◽  
Martina Conserva ◽  
...  
Keyword(s):  
Photon Emission ◽  
Polymyxin B ◽  
Sterile Inflammation ◽  
Unknown Etiology ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Positive Controls

Background: Infectious diseases are one of the main causes of morbidity and mortality worldwide. Nuclear molecular imaging would be of great help to non-invasively discriminate between septic and sterile inflammation through available radiopharmaceuticals, as none is currently available for clinical practice. Here, we describe the radiolabeling procedure and in vitro and in vivo studies of 99mTc-polymyxin B sulfate (PMB) as a new single photon emission imaging agent for the characterization of infections due to Gram-negative bacteria. Results: Labeling efficiency was 97 ± 2% with an average molar activity of 29.5 ± 0.6 MBq/nmol. The product was highly stable in saline and serum up to 6 h. In vitro binding assay showed significant displaceable binding to Gram-negative bacteria but not to Gram-positive controls. In mice, 99mTc-HYNIC-PMB was mainly taken up by liver and kidneys. Targeting studies confirmed the specificity of 99mTc-HYNIC-PMB obtained in vitro, showing significantly higher T/B ratios for Gram-negative bacteria than Gram-positive controls. Conclusions: In vitro and in vivo results suggest that 99mTc-HYNIC-PMB has a potential for in vivo identification of Gram-negative bacteria in patients with infections of unknown etiology. However, further investigations are needed to deeply understand the mechanism of action and behavior of 99mTc-HYNIC-PMB in other animal models and in humans.

scholarly journals Integrated endotoxin-adsorption and antibacterial properties of platelet-membrane-coated copper silicate hollow microspheres for wound healing

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Zaihui Peng ◽  
Xiaochun Zhang ◽  
Long Yuan ◽  
Ting Li ◽  
Yajie Chen ◽  
...  
Keyword(s):  
Wound Healing ◽  
Bacterial Infections ◽  
Antibacterial Properties ◽  
Platelet Membrane ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
The Impact ◽  
Copper Silicate

AbstractSerious infection caused by drug-resistant gram-negative bacteria and their secreted toxins (e.g., lipopolysaccharide) is a serious threat to human health. Thus, treatment strategies that efficiently kill bacteria and reducing the impact of their toxins simultaneously are urgently required. Herein, a novel antibacterial platform composed of a mesoporous copper silicate microsphere (CSO) core and a platelet membrane (PM) shell was prepared (CSO@PM). CSO@PM specifically targets bacteria owing to formyl peptide receptors on the PM and, combined with photothermal therapy (PTT), exhibits highly effective bacter icidal activity. Importantly, CSO@PM can adsorb lipopolysaccharide secreted by gram-negative bacteria, resulting in inflammation reduction. Thus, CSO@PM stimulates re-epithelialization and granulation-tissue formation, promoting wound healing. Moreover, this antibacterial platform exhibits no obvious toxicity at all the test concentrations in vitro and in vivo. Thus, CSO@PM exhibits a robust antibacterial effect and a strong toxin-adsorption capacity, facilitating the clinical treatment of many bacterial infections and the development of next-generation antibacterial nanoagents. Graphical Abstract

scholarly journals Integrated Endotoxin-Adsorption and Antibacterial Properties of Platelet-Membrane-Coated Copper Silicate Hollow Microspheres for Wound Healing

2021 ◽  
Author(s):  
Zaihui Peng ◽  
Xiaochun Zhang ◽  
Long Yuan ◽  
Yajie Chen ◽  
Ting Li ◽  
...  
Keyword(s):  
Wound Healing ◽  
Bacterial Infections ◽  
Antibacterial Properties ◽  
Platelet Membrane ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
The Impact ◽  
Copper Silicate

Abstract Serious infection caused by drug-resistant gram-negative bacteria and their secreted toxins (e.g., lipopolysaccharide) is a serious threat to human health. Thus, treatment strategies that efficiently kill bacteria and reducing the impact of their toxins simultaneously are urgently required. Herein, a novel antibacterial platform composed of a mesoporous copper silicate microsphere (CSO) core and a platelet membrane (PM) shell was prepared (CSO@PM). CSO@PM specifically targets bacteria owing to formyl peptide receptors on the PM and, combined with photothermal therapy (PTT), exhibits highly effective bactericidal activity. Importantly, CSO@PM can adsorb lipopolysaccharide secreted by gram-negative bacteria, resulting in inflammation reduction. Thus, CSO@PM stimulates re-epithelialization and granulation-tissue formation, promoting wound healing. Moreover, this antibacterial platform exhibits no obvious toxicity at all the test concentrations in vitro and in vivo. Thus, CSO@PM exhibits a robust antibacterial effect and a strong toxin-adsorption capacity, facilitating the clinical treatment of many bacterial infections and the development of next-generation antibacterial nanoagents.

scholarly journals Toxicity of metallic nanoparticles in the central nervous system

2019 ◽  
Vol 8 (1) ◽  
pp. 175-200 ◽  
Author(s):  
Krzysztof Sawicki ◽  
Magdalena Czajka ◽  
Magdalena Matysiak-Kucharek ◽  
Berta Fal ◽  
Bartłomiej Drop ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Metallic Nanoparticles ◽  
Current Knowledge ◽  
Negative Effects ◽  
Scientific Publications ◽  
The Central Nervous System ◽  
The Impact

Abstract Metallic nanoparticles due to their small size and unique physico-chemical characteristics have found excellent applications in various branches of industry and medicine. Therefore, for many years a growing interest has been observed among the scientific community in the improvement of our understanding of the impact of nanoparticles on the living organisms, especially on humans. Considering the delicate structure of the central nervous systemit is one of the organs most vulnerable to the adverse effects of metallic nanoparticles. For that reason, it is important to identify the modes of exposure and understand the mechanisms of the effect of nanoparticles on neuronal tissue. In this review, an attempt is undertaken to present current knowledge about metallic nanoparticles neurotoxicity based on the selected scientific publications. The route of entry of nanoparticles is described, as well as their distribution, penetration through the cell membrane and the blood-brain barrier. In addition, a study on the neurotoxicity in vitro and in vivo is presented, as well as some of the mechanisms that may be responsible for the negative effects of metallic nanoparticles on the central nervous system. Graphical abstract: This review summarizes the current knowledge on the toxicity of metallic NPs in the brain and central nervous system of the higher vertebrates.

scholarly journals Disrupting the leukemia niche in the central nervous system attenuates leukemia chemoresistance

2019 ◽  
Author(s):  
Leslie M. Jonart ◽  
Maryam Ebadi ◽  
Patrick Basile ◽  
Kimberly Johnson ◽  
Jessica Makori ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Lymphoblastic Leukemia ◽  
Leukemia Cells ◽  
Adhesion Assay ◽  
Hematopoietic Stem ◽  
The Central Nervous System ◽  
The Impact

AbstractProtection from acute lymphoblastic leukemia (ALL) relapse in the central nervous system (CNS) is crucial to survival and quality of life for ALL patients. Current CNS-directed therapies cause significant toxicities and are only partially effective. Moreover, the impact of the CNS microenvironment on leukemia biology is poorly understood. Herein, we showed that leukemia cells associated with the meninges of xenotransplanted mice, or co-cultured with meningeal cells, exhibit enhanced chemoresistance due to effects on both apoptosis balance and quiescence. From a mechanistic standpoint, we identified that leukemia chemoresistance is primarily mediated by direct leukemia-meningeal cell interactions and overcome by detaching the leukemia cells from the meninges. Next, we used a co-culture adhesion assay to identify drugs that disrupted leukemia-meningeal adhesion. In addition to identifying several drugs that inhibit canonical cell adhesion targets we found that Me6TREN, a novel hematopoietic stem cell (HSC) mobilizing compound, also disrupts leukemia-meningeal adhesion in vitro and in vivo. Finally, Me6TREN enhanced the efficacy of cytarabine in treating CNS leukemia in xenotransplanted mice. This work demonstrates that the meninges exert a critical influence on leukemia chemoresistance, elucidates mechanisms of CNS relapse beyond the well-described role of the blood-brain barrier, and identifies novel therapeutic approaches for overcoming chemoresistance.

scholarly journals In Vitro and In Vivo Antibacterial Activities of DW-224a, a New Fluoronaphthyridone

2006 ◽  
Vol 50 (6) ◽  
pp. 2261-2264 ◽  
Author(s):  
Hee-Soo Park ◽  
Hyun-Joo Kim ◽  
Min-Jung Seol ◽  
Dong-Rack Choi ◽  
Eung-Chil Choi ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
The Other ◽  
Vitro Activity ◽  
Gram Negative Bacteria ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.

scholarly journals INFLUENCE OF ANESTHESIA ON EXPERIMENTAL NEUROTROPIC VIRUS INFECTIONS

1946 ◽  
Vol 84 (4) ◽  
pp. 277-292 ◽  
Author(s):  
S. Edward Sulkin ◽  
Christine Zarafonetis ◽  
Andres Goth
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Diethyl Ether ◽  
Cervical Region ◽  
Virus Infections ◽  
Ether Anesthesia ◽  
Neurotropic Virus ◽  
Experimental Infections

Anesthesia with diethyl ether significantly alters the course and outcome of experimental infections with the equine encephalomyelitis virus (Eastern or Western type) or with the St. Louis encephalitis virus. No comparable effect is observed in experimental infections produced with rabies or poliomyelitis (Lansing) viruses. The neurotropic virus infections altered by ether anesthesia are those caused by viruses which are destroyed in vitro by this anesthetic, and those infections not affected by ether anesthesia are caused by viruses which apparently are not destroyed by ether in vitro. Another striking difference between these two groups of viruses is their pathogenesis in the animal host; those which are inhibited in vivo by ether anesthesia tend to infect cells of the cortex, basal ganglia, and only occasionally the cervical region of the cord. On the other hand, those which are not inhibited in vivo by ether anesthesia tend to involve cells of the lower central nervous system and in the case of rabies, peripheral nerves. This difference is of considerable importance in view of the fact that anesthetics affect cells of the lower central nervous system only in very high concentrations. It is obvious from the complexity of the problem that no clear-cut statement can be made at this point as to the mechanism of the observed effect of ether anesthesia in reducing the mortality rate in certain of the experimental neurotropic virus infections. Important possibilities include a direct specific effect of diethyl ether upon the virus and a less direct effect of the anesthetic upon the virus through its alteration of the metabolism of the host cell.

scholarly journals Astrocyte-Derived CCL2 is Associated with M1 Activation and Recruitment of Cultured Microglial Cells

2016 ◽  
Vol 38 (3) ◽  
pp. 859-870 ◽  
Author(s):  
Mingfeng He ◽  
Hongquan Dong ◽  
Yahui Huang ◽  
Shunmei Lu ◽  
Shu Zhang ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Microglial Activation ◽  
Culture Media ◽  
Microglial Cells ◽  
Migration Ability ◽  
Migration Assay ◽  
Tnf Α

Background/Aims: Microglia are an essential player in central nervous system inflammation. Recent studies have demonstrated that the astrocytic chemokine, CCL2, is associated with microglial activation in vivo. However, CCL2-induced microglial activation has not yet been studied in vitro. The purpose of the current study was to understand the role of astrocyte-derived CCL2 in microglial activation and to elucidate the underlying mechanism(s). Methods: Primary astrocytes were pre-treated with CCL2 siRNA and stimulated with TNF-α. The culture medium (CM) was collected and added to cultures of microglia, which were incubated with and without CCR2 inhibitor. Microglial cells were analyzed by quantitative RT-PCR to determine whether they polarized to the M1 or M2 state. Microglial migratory ability was assessed by transwell migration assay. Results: TNF-α stimulated the release of CCL2 from astrocytes, even if the culture media containing TNF-α was replaced with fresh media after 3 h. CM from TNF-α-stimulated astrocytes successfully induced microglial activation, which was ascertained by increased activation of M1 and enhanced migration ability. In contrast, CM from astrocytes pretreated with CCL2 siRNA showed no effect on microglial activation, compared to controls. Additionally, microglia pre-treated with RS102895, a CCR2 inhibitor, were resistant to activation by CM from TNF-α-stimulated astrocytes. Conclusion: This study demonstrates that the CCL2/CCR2 pathway of astrocyte-induced microglial activation is associated with M1 polarization and enhanced migration ability, indicating that this pathway could be a useful target to ameliorate inflammation in the central nervous system.

scholarly journals Polo-Like Kinase 4 (PLK4) Is Overexpressed in Central Nervous System Neuroblastoma (CNS-NB)

2018 ◽  
Vol 5 (4) ◽  
pp. 96 ◽  
Author(s):  
Anders Bailey ◽  
Amreena Suri ◽  
Pauline Chou ◽  
Tatiana Pundy ◽  
Samantha Gadd ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Brain Tumors ◽  
Meta Analysis ◽  
P Value ◽  
Embryonal Tumors ◽  
Expression Levels ◽  
Embryonal Brain

Neuroblastoma (NB) is the most common extracranial solid tumor in pediatrics, with rare occurrences of primary and metastatic tumors in the central nervous system (CNS). We previously reported the overexpression of the polo-like kinase 4 (PLK4) in embryonal brain tumors. PLK4 has also been found to be overexpressed in a variety of peripheral adult tumors and recently in peripheral NB. Here, we investigated PLK4 expression in NBs of the CNS (CNS-NB) and validated our findings by performing a multi-platform transcriptomic meta-analysis using publicly available data. We evaluated the PLK4 expression by quantitative real-time PCR (qRT-PCR) on the CNS-NB samples and compared the relative expression levels among other embryonal and non-embryonal brain tumors. The relative PLK4 expression levels of the NB samples were found to be significantly higher than the non-embryonal brain tumors (p-value < 0.0001 in both our samples and in public databases). Here, we expand upon our previous work that detected PLK4 overexpression in pediatric embryonal tumors to include CNS-NB. As we previously reported, inhibiting PLK4 in embryonal tumors led to decreased tumor cell proliferation, survival, invasion and migration in vitro and tumor growth in vivo, and therefore PLK4 may be a potential new therapeutic approach to CNS-NB.

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