Intravital imaging of a pulmonary endothelial surface layer in a murine sepsis model

Park, Inwon; Choe, Kibaek; Seo, Hyun-Ji; Hwang, Yoonha; Song, Eunjoo; Ahn, JoongHo; Jo, You Hwan; Kim, Pilhan

doi:10.1364/boe.9.002383

Cited by 29 publications

(25 citation statements)

References 52 publications

(92 reference statements)

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“…To visualise in vivo pulmonary microcirculation through a pulmonary imaging window, a custom-made video-rate laser scanning confocal microscopy system was implemented [21, 22]. Additional details of the imaging system and preparation of the mouse for intravital pulmonary imaging are provided in the supplementary material.…”

Section: Methodsmentioning

confidence: 99%

Neutrophils disturb pulmonary microcirculation in sepsis-induced acute lung injury

et al. 2019

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The lung is highly vulnerable during sepsis, yet its functional deterioration accompanied by disturbances in the pulmonary microcirculation is poorly understood. This study aimed to investigate how the pulmonary microcirculation is distorted in sepsis-induced acute lung injury (ALI) and reveal the underlying cellular pathophysiologic mechanism.Using a custom-made intravital lung microscopic imaging system in a murine model of sepsis-induced ALI, we achieved direct real-time visualisation of the pulmonary microcirculation and circulating cellsin vivo. We derived the functional capillary ratio (FCR) as a quantitative parameter for assessing the fraction of functional microvasculature in the pulmonary microcirculation and dead space.We identified that the FCR rapidly decreases in the early stage of sepsis-induced ALI. The intravital imaging revealed that this decrease resulted from the generation of dead space, which was induced by prolonged neutrophil entrapment within the capillaries. We further showed that the neutrophils had an extended sequestration time and an arrest-like dynamic behaviour, both of which triggered neutrophil aggregates inside the capillaries and arterioles. Finally, we found that Mac-1 (CD11b/CD18) was upregulated in the sequestered neutrophils and that a Mac-1 inhibitor restored the FCR and improved hypoxaemia.Using the intravital lung imaging system, we observed that Mac-1-upregulated neutrophil aggregates led to the generation of dead space in the pulmonary microcirculation that was recovered by a Mac-1 inhibitor in sepsis-induced ALI.

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Section: Methodsmentioning

confidence: 99%

Neutrophils disturb pulmonary microcirculation in sepsis-induced acute lung injury

et al. 2019

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“…The number of neutrophils per mm 2 vessel area was then determined for each animal. To estimate the blood flow velocity within the sinusoids, red blood cells (RBC) were identified using negative staining within the dextran channel [23] and their velocities were measured using MTrackJ plugin in FIJI/ImageJ [24]. Tracks were created by manually selecting the center of RBC through a series of frames.…”

Section: Imaging and Image Analysis Of Intravital Microscopy Experimentsmentioning

confidence: 99%

The vimentin rod domain blocks P-selectin-P-selectin glycoprotein ligand 1 interactions to attenuate leukocyte adhesion to inflamed endothelium

et al. 2020

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Acute inflammation begins with leukocyte P-selectin glycoprotein ligand-1 (PSGL-1) binding to P-selectin on inflamed endothelium and platelets. In pathologic conditions, this process may contribute to secondary organ damage, like sepsis-induced liver injury. Therefore, developing novel therapies to attenuate inflammation may be beneficial. We previously reported that recombinant human vimentin (rhVim) binds P-selectin to block leukocyte adhesion to endothelium and platelets. In this study, we used SPOT-peptide arrays to identify the rod domain as the active region within rhVim that interacts with P-selectin. Indeed, recombinant human rod domain of vimentin (rhRod) binds to P-selectin with high affinity, with in silico modeling suggesting that rhRod binds P-selectin at or near the PSGL-1 binding site. Using bio-layer interferometry, rhRod decreases PSGL-1 binding to immobilized P-selectin, corroborating the in silico data. Under parallel-plate flow, rhRod blocks leukocyte adhesion to fibrin (ogen)-captured platelets, P-selectin/Fc-coated channels, and IL-1β/IL-4-co-stimulated human umbilical vein endothelial cells. Finally, using intravital microscopy in endotoxemic C57Bl/6 mice, rhRod co-localizes with P-selectin in the hepatic sinusoids and decreases neutrophil adhesion to hepatic sinusoids. These data suggest a potential role for rhRod in attenuating inflammation through directly blocking P-selectin-PSGL-1 interactions.

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“…d BLI detection of luciferase reporter-labelled MSCs administered IV demonstrating a lower sensitivity than PET/SPECT and external anatomical structure alluding to in vivo cell location [126]. e , f Intravital microscopy imaging of live tissues demonstrating the specificity of labelling at the cellular level (pulmonary tissue; cytoplasm = red, nuclei = green) [127]. g GFP-labelled MSCs detected in lung tissue sections (green) with cell nuclei clearly visible (blue) [128].…”

Section: Methods Of Imaging Msc Distribution and Fatementioning

confidence: 99%

Modulating the distribution and fate of exogenously delivered MSCs to enhance therapeutic potential: knowns and unknowns

Masterson

Curley

Laffey

2019

ICMx

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Mesenchymal stem/stromal cells (MSCs) are undergoing intensive translational research for several debilitating conditions, including critical illnesses such as ARDS and sepsis. MSCs exert diverse biologic effects via their interaction with host tissues, via mechanisms that require the MSC to be in close proximity to the area of injury. Fully harnessing the therapeutic potential of advanced medicinal therapeutic products such as MSCs and their successful translation to clinical use requires a detailed understanding of MSC distribution and persistence in the injured tissues. Key aspects include understanding MSC distribution within the body, the response of the host to MSC administration, and the ultimate fate of exogenously administered MSCs within the host. Factors affecting this interaction include the MSC tissue source, the in vitro MSC culture conditions, the route of MSC administration and the specific issues relating to the target disease state, each of which remains to be fully characterised. Understanding these factors may generate strategies to modify MSC distribution and fate that may enhance their therapeutic effect. This review will examine our understanding of the mechanisms of action of MSCs, the early and late phase distribution kinetics of MSCs following in vivo administration, the ultimate fate of MSCs following administration and the potential importance of these MSC properties to their therapeutic effects. We will critique current cellular imaging and tracking methodologies used to track exogenous MSCs and their suitability for use in patients, discuss the insights they provide into the distribution and fate of MSCs after administration, and suggest strategies by which MSC biodistribution and fate may be modulated for therapeutic effect and clinical use. In conclusion, a better understanding of patterns of biodistribution and of the fate of MSCs will add important additional safety data regarding MSCs, address regulatory requirements, and may uncover strategies to increase the distribution and/or persistence of MSC at the sites of injury, potentially increasing their therapeutic potential for multiple disorders.

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Intravital imaging of a pulmonary endothelial surface layer in a murine sepsis model

Cited by 29 publications

References 52 publications

Neutrophils disturb pulmonary microcirculation in sepsis-induced acute lung injury

Neutrophils disturb pulmonary microcirculation in sepsis-induced acute lung injury

The vimentin rod domain blocks P-selectin-P-selectin glycoprotein ligand 1 interactions to attenuate leukocyte adhesion to inflamed endothelium

Modulating the distribution and fate of exogenously delivered MSCs to enhance therapeutic potential: knowns and unknowns

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