optical-screening-novel-bacteria-specific-probes-on-ex-vivo-human

Optical Screening of Novel Bacteria-specific Probes on <em>Ex Vivo</em> Human Lung Tissue by Confocal Laser Endomicroscopy

Improving the speed and accuracy of bacterial detection is important for patient stratification and to ensure the appropriate use of antimicrobials. To ...

University of Edinburgh

Circadian (c. 24 h) rhythms of physiology are entrained to either the environmental light-dark cycle or the timing of food intake. In the current work the hypothesis that rhythms of platelet turnover in mammals are circadian and entrained by food intake was explored in mice. Mice were entrained to 12 h light-dark cycles and given either ad libitum (AL) or restricted access (RF) to food during the light phase. Blood and megakaryocytes were then collected from mice every 4 h for 24 h. It was found that total and reticulated platelet numbers, plasma thrombopoietin (TPO) concentration and the mean size of mature megakaryocytes were circadian but not entrained by food intake. In contrast, a circadian rhythm in the expression of Arnt1 in megakaryocytes was entrained by food. Although not circadian, the expression in megakaryocytes of Nfe2, Gata1, Itga2b and Tubb1 expression was downregulated by RF, whereas Ccnd1 was not significantly affected by the feeding protocol. It is concluded that circadian rhythms of total platelet number, reticulated platelet number and plasma TPO concentration are entrained by the light-dark cycle rather than the timing of food intake. These findings imply that circadian clock gene expression regulates platelet turnover in mammals.

Timed feeding of mice modulates light-entrained circadian rhythms of reticulated platelet abundance and plasma thrombopoietin and affects gene expression in megakaryocytes.

Acute lung injury (ALI) is an important cause of morbidity and mortality, with no currently effective pharmacological therapies. Neutrophils have been specifically implicated in the pathogenesis of ALI, and there has been significant research into the mechanisms of early neutrophil recruitment, but those controlling the later phases of neutrophil emigration that characterize disease are poorly understood.

Monocytes control second-phase neutrophil emigration in established lipopolysaccharide-induced murine lung injury.

We demonstrate a fast two-color widefield fluorescence microendoscopy system capable of simultaneously detecting several disease targets in intact human ex vivo lung tissue. We characterize the system for light throughput from the excitation light emitting diodes, fluorescence collection efficiency, and chromatic focal shifts. We demonstrate the effectiveness of the instrument by imaging bacteria (Pseudomonas aeruginosa) in ex vivo human lung tissue. We describe a mechanism of bacterial detection through the fiber bundle that uses blinking effects of bacteria as they move in front of the fiber core providing detection of objects smaller than the fiber core and cladding (∼3  μm ∼3  μm ). This effectively increases the measured spatial resolution of 4  μm 4  μm . We show simultaneous imaging of neutrophils, monocytes, and fungus (Aspergillus fumigatus) in ex vivo human lung tissue. The instrument has 10 nM and 50 nM sensitivity for fluorescein and Cy5 solutions, respectively. Lung tissue autofluorescence remains visible at up to 200 fps camera acquisition rate. The optical system lends itself to clinical translation due to high-fluorescence sensitivity, simplicity, and the ability to multiplex several pathological molecular imaging targets simultaneously.

Two-color widefield fluorescence microendoscopy enables multiplexed molecular imaging in the alveolar space of human lung tissue.

Infections arising from contaminated medical devices are a serious global issue, contributing to antibiotic resistance and imposing significant strain on healthcare systems. Since the majority of medical device-associated infections are biofilm related, efforts are being made to generate either bacteria-repellent or antibacterial coatings aimed at preventing bacterial colonisation. Here, we utilise a nanocapsule mediated slow release of a natural antimicrobial to improve the performance of a bacteria repellent polymer coating. Poly(lauryl acrylate) nanocapsules containing eugenol (4-allyl-2-methoxyphenol) were prepared and entrapped within a interpenetrating network designed to repel bacteria. When coated on a catheter and an endotracheal tube, this hemocompatible system allowed slow-release of eugenol, resulting in notable reduction in surface-bound Klebsiella pneumoniae and methicillin resistant Staphylococcus aureus.

Fortified interpenetrating polymers - bacteria resistant coatings for medical devices.

Acute respiratory distress syndrome (ARDS) is an often fatal neutrophil-dominant lung disease. Although influenced by multiple proinflammatory mediators, identification of suitable therapeutic candidates remains elusive. We aimed to delineate the presence of mitochondrial formylated peptides in ARDS and characterise the functional importance of formyl peptide receptor 1 (FPR1) signalling in sterile lung inflammation.

Article	Year
Timed feeding of mice modulates light-entrained circadian rhythms of reticulated platelet abundance and plasma thrombopoietin and affects gene expression in megakaryocytes. British journal of haematology\| PubMed ID: 19438469	2009
Monocytes control second-phase neutrophil emigration in established lipopolysaccharide-induced murine lung injury. American journal of respiratory and critical care medicine\| PubMed ID: 22822022	2012
Two-color widefield fluorescence microendoscopy enables multiplexed molecular imaging in the alveolar space of human lung tissue. Journal of biomedical optics\| PubMed ID: 27121475	2016
Fortified interpenetrating polymers - bacteria resistant coatings for medical devices. Journal of materials chemistry. B, Materials for biology and medicine\| PubMed ID: 27746915	2016
Novel role for endogenous mitochondrial formylated peptide-driven formyl peptide receptor 1 signalling in acute respiratory distress syndrome. Thorax\| PubMed ID: 28469031	2017

Emma Scholefield

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