stabilized-longitudinal-vivo-cellular-level-visualization-pancreas

Stabilized Longitudinal <em>In Vivo</em> Cellular-Level Visualization of the Pancreas in a Murine Model with a Pancreatic Intravital Imaging Window

Direct in vivo cellular-resolution imaging of the pancreas in a live small animal model has been technically challenging. A recent intravital imaging ...

Seoul National University bundang hospital

Direct intravital imaging of an endothelial surface layer (ESL) in pulmonary microcirculation could be a valuable approach to investigate the role of a vascular endothelial barrier in various pathological conditions. Despite its importance as a marker of endothelial cell damage and impairment of the vascular system,  visualization of ESL has remained a challenging technical issue. In this work, we implemented a pulmonary microcirculation imaging system integrated to a custom-design video-rate laser scanning confocal microscopy platform. Using the system, a real-time cellular-level microscopic imaging of the lung was successfully performed, which facilitated a clear identification of individual flowing erythrocytes in pulmonary capillaries. Subcellular level pulmonary ESL was identified  by fluorescence angiography using a dextran conjugated fluorophore to label blood plasma and the red blood cell (RBC) exclusion imaging analysis. Degradation of ESL width was directly evaluated in a murine sepsis model , suggesting an impairment of pulmonary vascular endothelium and endothelial barrier dysfunction.

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

Vagus nerve stimulation (VNS) during post-resuscitation may increase recovery of cerebral blood flow (CBF) and reduce neurological injury.

Effect of Electrical Vagus Nerve Stimulation on Cerebral Blood Flow and Neurological Outcome in Asphyxial Cardiac Arrest Model of Rats.

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 cells  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.

Neutrophils disturb pulmonary microcirculation in sepsis-induced acute lung injury.

Automated surveillance for cardiac arrests would be useful in overcrowded emergency departments. The purpose of this study is to develop and test artificial neural network (ANN) classifiers for early detection of patients at risk of cardiac arrest in emergency departments.

Developing neural network models for early detection of cardiac arrest in emergency department.

Longitudinal imaging of murine pancreas is technically challenging due to the mechanical softness of the tissue influenced by peristalsis. Here, we report a novel pancreatic imaging window for long-term stabilized cellular-level observation of the islets in the pancreas . By spatially separating the pancreas from the bowel movement and physiologic respiration with a metal plate integrated in the imaging window, we successfully tracked the pancreatic islets up to three weeks and visualized the dumbbell-shape transformation from the single islet. This window can be a useful tool for long-term cellular-level visualization of the microstructure in the pancreas.

A Novel Pancreatic Imaging Window for Stabilized Longitudinal  Observation of Pancreatic Islets in Murine Model.

, longitudinal observation of tumorigenesis in a live mouse model over an extended time period has been actively pursued to obtain a better understanding of the cellular and molecular mechanism in a highly complex tumor microenvironment. However, common intravital imaging approaches based on a conventional laser scanning confocal or a two-photon microscope have been mostly limited to the observation of superficial parts of the solid tumor tissue. In this work, we implemented a small diameter needle-shaped side-view confocal endomicroscope that can be directly inserted into a solid tumor in a minimally-invasive manner . By inserting the side-view endomicroscope into the breast tumor from the surface, we achieved  depth-wise cellular-level visualization of microvasculature and fluorescently labeled tumor cells located deeply inside the tumor. In addition, we successfully performed longitudinal depth-wise visualization of a growing breast tumor over three weeks in a live mouse model, which revealed dynamic changes in microvasculature such as a decreasing amount of intratumoral blood vessels over time.

 longitudinal depth-wise visualization of tumorigenesis by needle-shaped side-view confocal endomicroscopy.

Although there are well-established small-animal sepsis models, the longitudinal assessment of hemodynamic variables, laboratory values, and blood culture in a single living sepsis model is limited. Therefore, we aimed to comprehensively characterize fecal peritonitis-induced sepsis in a porcine model.

Characterization of Fecal Peritonitis-Induced Sepsis in a Porcine Model.

Although initial fluid resuscitation in sepsis is critical for the treatment of tissue hypoperfusion, little evidence supports the distribution of infused fluid in patients with sepsis. This study was designed to assess the body water distribution in patients with sepsis using bioelectrical impedance analysis and correlate the trend in body water distribution during fluid treatment with the prognosis of patients with sepsis.

Assessment of body water distribution in patients with sepsis during fluid resuscitation using multi-frequency direct segmental bioelectrical impedance analysis.

We hypothesized utilizing machine learning (ML) algorithms for screening septic shock in ED would provide better accuracy than qSOFA or MEWS.

Machine learning for prediction of septic shock at initial triage in emergency department.

It is not easy to ensure optimal prevention of hospital-acquired pressure ulcer (HAPU) in crowded emergency departments (EDs). We hypothesised that a prolonged ED length of stay (LOS) is associated with an increased risk of HAPU. This is a single-centre observational study. Prospectively collected HAPU surveillance data were analysed. Adult (aged ≥20 years) patients admitted through the ED from April 1, 2013 to December 31, 2016 were included. The primary outcome was the development of HAPU within a month. Covariates included demographics, comorbidities, conditions at triage, initial laboratory results, primary ED diagnosis, critical ED interventions, and ED dispositions. The association between ED LOS and HAPU was modelled using logistic and extended Cox regression. A total of 48 641 admissions were analysed. The crude odds ratio (OR) and hazard ratio (HR) for HAPU were increased to 1.44 (95% CI, 1.20-1.72) and 1.21 (95% CI, 1.02-1.45), respectively, in ED LOS ≥24 hours relative to ED LOS <6 hours. In multivariable logistic regression, ED LOS ≥12 and ≥24 hours were associated with higher risk of HAPU, with ORs of 1.30 (95% CI, 1.05-1.60) and 1.80 (95% CI, 1.45-2.23) relative to ED LOS <6 hours, respectively. The extended Cox regression showed that the risk lasted up to a week, with HRs of 1.42 (95% CI, 1.07-1.88) and 1.92 (95% CI, 1.44-2.57) relative to ED LOS <6 hours, respectively. In conclusion, Prolonged ED LOS is independently associated with HAPU. Shorter ED LOS should be pursued as a goal in a multifaceted solution for HAPU.

Prolonged stay in the emergency department is an independent risk factor for hospital-acquired pressure ulcer.

Fine particulate matter 2.5 (PM2.5) is a harmful air pollutant currently threatening public health. Although many studies have been performed on the general negative effects of PM2.5 in mice and humans, the migration patterns of various immune cells in response to PM2.5 exposure remain unclear. In this study, we aimed to investigate the immune cell migratory response in the lung and the liver of intratracheally PM2.5-inoculated mice. To investigate the migration trajectory of immune cells in the lung and the liver tissues of mice, we employed microscopic tools including two-photon intravital imaging, histological analysis, and transmission electron microscopy. Our data from two-photon intravital imaging showed that there was no significant difference in the number of infiltrated neutrophils in the lung and the liver of PM2.5-treated mice, compared to the nontreated condition. However, from the histological analysis and the transmission electron microscopy after vascular perfusion to remove intravascular leukocytes, we observed that some leukocytes were frequently observed in the lung and the liver of PM2.5-treated mice. Interestingly, quantification of leukocyte population using flow cytometry showed significant increase of neutrophils and macrophages in the lung, but not much in the liver, 24 h post-PM2.5 treatment. These data imply that two-photon intravital imaging of the lung and the liver actually visualized neutrophils, which were adherent to the luminal side of the vasculature. We then conducted mRNA microarray analysis to further observe how PM2.5 affects gene expression patterns in the lung and the liver. PM2.5 treatment changed the mRNA expression associated with the IL-17 signaling pathway in the lung and changed the mRNA expression associated with metabolic pathways in the liver. In summary, these results suggest that the immune response in the lung is distinctly regulated from that in the liver under acute PM2.5-induced inflammation and that these organs consequently are regulated via distinct signaling pathways.

PM2.5 Exposure in the Respiratory System Induces Distinct Inflammatory Signaling in the Lung and the Liver of Mice.

Metabolic acidosis is commonly associated with the disease severity in patients with sepsis or septic shock. This study was performed to investigate the association between serum total carbon dioxide (TCO concentration and 28-day mortality in patients with sepsis.

Serum total carbon dioxide as a prognostic factor for 28-day mortality in patients with sepsis.

Ischaemic tissue injury caused by tissue hypoperfusion is one of the major consequences of sepsis. Phosphate concentrations are elevated in ischaemic tissue injury. This study was performed to investigate the association of phosphate concentrations with mortality in patients with sepsis.

Moderate to severe hyperphosphataemia as an independent prognostic factor for 28-day mortality in adult patients with sepsis.

An index combining respiratory rate and oxygenation (ROX) has been introduced, and the ROX index is defined as the ratio of oxygen saturation by pulse oximetry/fraction of inspired oxygen to respiratory rate. In sepsis, hypoxemia and tachypnea are commonly observed. We performed this study to investigate the association between the ROX index and 28-day mortality in patients with sepsis or septic shock.

Article	Year
Intravital imaging of a pulmonary endothelial surface layer in a murine sepsis model. Biomedical optics express\| PubMed ID: 29760995	2018
Effect of Electrical Vagus Nerve Stimulation on Cerebral Blood Flow and Neurological Outcome in Asphyxial Cardiac Arrest Model of Rats. Neurocritical care\| PubMed ID: 30382532	2019
Neutrophils disturb pulmonary microcirculation in sepsis-induced acute lung injury. The European respiratory journal\| PubMed ID: 30635296	2019
Developing neural network models for early detection of cardiac arrest in emergency department. The American journal of emergency medicine\| PubMed ID: 30982559	2020
A Novel Pancreatic Imaging Window for Stabilized Longitudinal Observation of Pancreatic Islets in Murine Model. Diabetes & metabolism journal\| PubMed ID: 31237131	2020
longitudinal depth-wise visualization of tumorigenesis by needle-shaped side-view confocal endomicroscopy. Biomedical optics express\| PubMed ID: 31259046	2019
Characterization of Fecal Peritonitis-Induced Sepsis in a Porcine Model. The Journal of surgical research\| PubMed ID: 31330293	2019
Assessment of body water distribution in patients with sepsis during fluid resuscitation using multi-frequency direct segmental bioelectrical impedance analysis. Clinical nutrition (Edinburgh, Scotland)\| PubMed ID: 31416662	2020
Machine learning for prediction of septic shock at initial triage in emergency department. Journal of critical care\| PubMed ID: 31734491	2020
Prolonged stay in the emergency department is an independent risk factor for hospital-acquired pressure ulcer. International wound journal\| PubMed ID: 31773872	2020
PM2.5 Exposure in the Respiratory System Induces Distinct Inflammatory Signaling in the Lung and the Liver of Mice. Journal of immunology research\| PubMed ID: 31871955	2019
Serum total carbon dioxide as a prognostic factor for 28-day mortality in patients with sepsis. The American journal of emergency medicine\| PubMed ID: 32303411	2020
Moderate to severe hyperphosphataemia as an independent prognostic factor for 28-day mortality in adult patients with sepsis. Emergency medicine journal : EMJ\| PubMed ID: 32321706	2020
The index of oxygenation to respiratory rate as a prognostic factor for mortality in Sepsis. The American journal of emergency medicine\| PubMed ID: 33039213	2020

Inwon Park

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