scholarly journals Assessing acute and chronic Staphylococcus aureus growth and virulence in an ex vivo model of cystic fibrosis lung infection

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Branagh Crealock-Ashurst ◽  
Freya Harrison ◽  
Esther Sweeney
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Ex Vivo ◽  
Bacterial Load ◽  
Clinical Results ◽  
Lung Model ◽  
Clinical State ◽  
Ex Vivo Model ◽  
Significant Difference ◽  
Factor Assay

Staphylococcus aureus is routinely found in sputum samples obtained from people with Cystic Fibrosis (CF). However, its role in the progression of the disease is unclear. This is important, as antibiotic clearance of S. aureus in CF yields unclear clinical results and there is debate around the utility of anti-Staphylococcal antibiotic treatment. We used an ex vivo porcine lung model (EVPL) to compare the growth and virulence of S. aureus isolates from acute CF exacerbations, with isolates from the same donors when they were stable. There was no significant difference in mean bacterial load between donors, strains or clinical state. However, when we compared the variance in bacterial load of each pair of exacerbation/stable isolates across experimental replicates of the lung model, we found that stable samples grew more consistently in the EVPL compared to those taken from the same donor during an exacerbation. Virulence factor assay results were mixed, with results implying greater virulence in either stable or acute samples after passage through the EVPL. We could not detect the AIP quorum sensing signal, which control expression of numerous acute virulence factors, using a reporter assay. We hypothesise that S. aureus might down-regulate Agr expression in the model, consistent with a role as a silent persister, rather than as a pathogenic agent. Further work using the EVPL model will determine how well this reflects the clinical reality in CF.

scholarly journals Anti-pseudomonad Activity of Manuka Honey and Antibiotics in a Specialized ex vivo Model Simulating Cystic Fibrosis Lung Infection

2019 ◽  
Vol 10 ◽  
Author(s):  
Aled E. L. Roberts ◽  
Lydia C. Powell ◽  
Manon F. Pritchard ◽  
David W. Thomas ◽  
Rowena E. Jenkins
Keyword(s):  
Cystic Fibrosis ◽  
Ex Vivo ◽  
Lung Infection ◽  
Cystic Fibrosis Lung ◽  
Manuka Honey ◽  
Ex Vivo Model

scholarly journals Assisting PNA Transport Through Cystic Fibrosis Human Airway Epithelia With Biodegradable Hybrid Lipid-Polymer Nanoparticles

2020 ◽  
Author(s):  
Marika Comegna ◽  
Gemma Conte ◽  
Andrea Falanga ◽  
Maria Marzano ◽  
Gustavo Cernera ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Ex Vivo ◽  
Release Kinetics ◽  
In Vitro Release ◽  
Target Cells ◽  
Ex Vivo Model ◽  
Shell Nanoparticles ◽  
Main Challenge ◽  
Mucus Barrier

Abstract Cystic Fibrosis (CF) is characterized by an airway obstruction caused by a thick mucus due to a malfunctioning Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein. The sticky mucus restricts drugs in reaching target cells limiting the efficiency of treatments. The development of new approaches to enhance drug delivery to the lungs represents CF treatment's main challenge. In this work, we report the synthesis and characterization of hybrid core-shell nanoparticles (hNPs) comprising a PLGA core and a dipalmitoylphosphatidylcholine (DPPC) shell engineered for inhalation. We loaded hNPs with a 7-mer peptide nucleic acid (PNA) previously considered for its ability to modulate the post-transcriptional regulation of the CFTR gene. We also investigated the in vitro release kinetics of hNPs and their efficacy in PNA delivery across the human epithelial airway barrier using an ex vivo model based on human primary nasal epithelial cells (HNEC) from CF patients. Confocal analyses and hNPs transport assay demonstrated the ability of hNPs to overcome the mucus barrier and release their PNA cargo within the cytoplasm, where it can perform its biological function.

scholarly journals Anex vivocystic fibrosis model recapitulates key clinical aspects of chronicStaphylococcus aureusinfection

2019 ◽  
Author(s):  
Esther Sweeney ◽  
Marwa M. Hassan ◽  
Niamh E. Harrington ◽  
Alan R. Smyth ◽  
Matthew N. Hurley ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Ex Vivo ◽  
Lung Model ◽  
Clinical Aspects ◽  
Small Colony Variant ◽  
Tissue Invasion ◽  
Disease Characteristics ◽  
Small Colony ◽  
Clinically Significant

AbstractStaphylococcus aureusis one of the most prevalent organisms isolated from the airways of people with cystic fibrosis (CF), predominantly early in life. Yet its role in the pathology of lung disease is poorly understood. Clinical studies are limited in scope by age and health of participants andin vitrostudies are not always able to accurately recapitulate chronic disease characteristics such as the development of small colony variants. Further, animal models also do not fully represent features of clinical disease: in particular, mice are not readily colonized byS. aureusand when infection is established it leads to the formation of abscesses, a phenomenon almost never observed in the human CF lung. Here, we present details of the development of an existingex vivopig lung model of CF infection to investigate the growth ofS. aureus. We show thatS. aureusis able to establish infection and demonstrates clinically significant characteristics including small colony variant phenotype, increased antibiotic tolerance and preferential localisation in mucus. Tissue invasion and the formation of abscesses were not observed, in line with clinical data.

scholarly journals Assisting PNA transport through cystic fibrosis human airway epithelia with biodegradable hybrid lipid-polymer nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marika Comegna ◽  
Gemma Conte ◽  
Andrea Patrizia Falanga ◽  
Maria Marzano ◽  
Gustavo Cernera ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Ex Vivo ◽  
Release Kinetics ◽  
In Vitro Release ◽  
Target Cells ◽  
Ex Vivo Model ◽  
Shell Nanoparticles ◽  
Main Challenge ◽  
Mucus Barrier

AbstractCystic fibrosis (CF) is characterized by an airway obstruction caused by a thick mucus due to a malfunctioning Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein. The sticky mucus restricts drugs in reaching target cells limiting the efficiency of treatments. The development of new approaches to enhance drug delivery to the lungs represents CF treatment's main challenge. In this work, we report the production and characterization of hybrid core–shell nanoparticles (hNPs) comprising a PLGA core and a dipalmitoylphosphatidylcholine (DPPC) shell engineered for inhalation. We loaded hNPs with a 7-mer peptide nucleic acid (PNA) previously considered for its ability to modulate the post-transcriptional regulation of the CFTR gene. We also investigated the in vitro release kinetics of hNPs and their efficacy in PNA delivery across the human epithelial airway barrier using an ex vivo model based on human primary nasal epithelial cells (HNEC) from CF patients. Confocal analyses and hNPs transport assay demonstrated the ability of hNPs to overcome the mucus barrier and release their PNA cargo within the cytoplasm, where it can exert its biological function.

scholarly journals Comparison of Extracapsular Stabilization Techniques Using an Ultrasonically Implanted Absorbable Bone Anchor (Weldix) after Cranial Cruciate Ligament Rupture in Cats—An In Vitro Study

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1695
Author(s):  
Lydia Koch ◽  
Barbara Bockstahler ◽  
Alexander Tichy ◽  
Christian Peham ◽  
Eva Schnabl-Feichter
Keyword(s):  
Internal Rotation ◽  
Ex Vivo ◽  
Cruciate Ligament ◽  
Joint Stability ◽  
Bone Anchor ◽  
Ex Vivo Model ◽  
Cranial Cruciate Ligament ◽  
Stifle Joint ◽  
Significant Difference

Background: This study evaluated joint stability after surgical repair of cranial cruciate ligament (CrCL)-deficient stifle joints in cats using a novel absorbable polylactide bone anchor in an ex vivo model. Methods: Thirty-six hindlimbs from cats with intact (Gi group) and transected CrCLs were treated with fabellotibial suture alone (GFW group), suture combined with an absorbable polylactide bone anchor (GWD group), or suture combined with a nonabsorbable bone anchor (GFT group), positioned in a limb press with predefined joint angles (stifle joint: 120 ± 5°; hock joint: 120 ± 5°) and loaded with 10%, 20%, and 30% of body mass (BM). Predefined points were measured on lateral radiographs and with a coordinate measurement machine. Distances on radiographs (mm) were measured and angles (°) were calculated to represent the craniocaudal movement and the internal rotation of the tibia. Results: There were no differences for craniocaudal movement between Gi and GFW or GFT, but for GWD regarding angle measurement at 30% BM. For internal rotation, there was no significant difference between Gi and GFW or GWD, but for GFT. Conclusion: The used absorbable polylactide bone-anchor was able to stabilize the stifle joint regarding internal rotation and craniocaudal movement as calculated from distance measurements.

scholarly journals Towards the Development of a Novel Ex Ovo Model of Infection to Pre-Screen Biomaterials Intended for Treating Chronic Wounds

2020 ◽  
Vol 11 (2) ◽  
pp. 37 ◽  
Author(s):  
Elena García-Gareta ◽  
Justyna Binkowska ◽  
Nupur Kohli ◽  
Vaibhav Sharma
Keyword(s):  
Staphylococcus Aureus ◽  
Persistent Infection ◽  
Scientific Community ◽  
Chronic Wounds ◽  
Ex Vivo ◽  
Chorioallantoic Membrane ◽  
Antimicrobial Properties ◽  
Ex Vivo Model ◽  
Angiogenic Potential ◽  
Chick Embryo Chorioallantoic Membrane

This communication reports preliminary data towards the development of a live ex vivo model of persistent infection that is based on the chick embryo chorioallantoic membrane (CAM), which can be used for pre-screening biomaterials with antimicrobial properties for their antimicrobial and angiogenic potential. Our results showed that it was possible to infect chicken embryos with Staphylococcus aureus, one of the main types of bacteria found in the persistent infection associated with chronic wounds, and maintain the embryos’ survival for up to 48 h. Survival of the embryos varied with the dose of bacteria inoculum and with the use and time of streptomycin application after infection. In infected yet viable embryos, the blood vessels network of the CAM was maintained with minimal disruption. Microbiological tests could confirm embryo infection, but quantification was difficult. By publishing these preliminary results, we hope that not only our group but others within the scientific community further this research towards the establishment of biomimetic and reproducible ex vivo models of persistent infection.

scholarly journals Keratinocyte growth factor attenuates hydrostatic pulmonary edema in an isolated, perfused rat lung model

2001 ◽  
Vol 280 (3) ◽  
pp. H1311-H1317 ◽  
Author(s):  
David A. Welsh ◽  
Benoit P. H. Guery ◽  
Bennett P. Deboisblanc ◽  
Elizabeth P. Dobard ◽  
Colette Creusy ◽  
...  
Keyword(s):  
Growth Factor ◽  
Pulmonary Edema ◽  
Ex Vivo ◽  
Keratinocyte Growth Factor ◽  
Lung Model ◽  
Rat Lung ◽  
Ex Vivo Model ◽  
Lung Weight ◽  
Edema Formation ◽  
Alveolar Epithelial

Hydrostatic pulmonary edema is a common complication of congestive heart failure, resulting in substantial morbidity and mortality. Keratinocyte growth factor (KGF) is a mitogen for type II alveolar epithelial and microvascular cells. We utilized the isolated perfused rat lung model to produce hydrostatic pulmonary edema by varying the left atrial and pulmonary capillary pressure. Pretreatment with KGF attenuated hydrostatic edema formation. This was demonstrated by lower wet-to-dry lung weight ratios, histological evidence of less alveolar edema formation, and reduced alveolar accumulation of intravascularly administered FITC-labeled large-molecular-weight dextran in rats pretreated with KGF. Thus KGF attenuates injury in this ex vivo model of hydrostatic pulmonary edema via mechanisms that prevent increases in alveolar-capillary permeability.

scholarly journals An ex vivo lung model to study bronchioles infected with Pseudomonas aeruginosa biofilms

2016 ◽  
Author(s):  
Freya Harrison ◽  
Stephen P. Diggle
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Resistance ◽  
Predictive Power ◽  
Ex Vivo ◽  
Opportunistic Pathogen ◽  
Lung Infection ◽  
Bacterial Virulence ◽  
Lung Model ◽  
Physical And Chemical

AbstractA key aim in microbiology is to determine the genetic and phenotypic bases of bacterial virulence, persistence and antimicrobial resistance in chronic biofilm infections. This requires tractable, high-throughput models that reflect the physical and chemical environment encountered in specific infection contexts. Such models will increase the predictive power of microbiological experiments and provide platforms for enhanced testing of novel antibacterial or antivirulence therapies. We present an optimised ex vivo model of cystic fibrosis lung infection: ex vivo culture of pig bronchiolar tissue in artificial cystic fibrosis mucus. We focus on the formation of biofilms by Pseudomonas aeruginosa. We show highly repeatable and specific formation of biofilms that resemble clinical biofilms by a commonly-studied lab strain and ten cystic fibrosis isolates of this key opportunistic pathogen.

Sign in / Sign up

Export Citation Format

Share Document