Ms. Avira Som Profile

Avira Som

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Publications (3)

Proceedings Article | 24 April 2017 Presentation

Use of micro-optical coherence tomography to analyze barrier integrity of intestinal epithelial cells (Conference Presentation)

Avira Som, Hui Min Leung, Kengyeh Chu, Alex Eaton, Bryan Hurley, Guillermo Tearney

Proceedings Volume 10068, 1006809 (2017) https://doi.org/10.1117/12.2252727

KEYWORDS: Pathogens, Tomography, Resistance, Optical coherence tomography, Digestive system, Stomach, Image resolution, Coherence (optics), 3D image processing, Video

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Proceedings Article | 19 April 2017 Presentation

In vivo OCT imaging of the airways (Conference Presentation)

Hui Min Leung, Lael Yonker, Hongmei Mou, Avira Som, Bryan Hurley, Guillermo Tearney

Proceedings Volume 10041, 1004103 (2017) https://doi.org/10.1117/12.2252160

KEYWORDS: In vivo imaging, Biology, Medical research, Biological research, Optical coherence tomography, Tomography, Image resolution, Cystic fibrosis, Coherence (optics), Real time imaging

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Proceedings Article | 27 April 2016 Presentation

Imaging neutrophil migration dynamics using micro-optical coherence tomography (Conference Presentation)

Kengyeh Chu, Lael Yonker, Avira Som, Michael Pazos, Mark Kusek, Bryan Hurley, Guillermo Tearney

Proceedings Volume 9709, 97090G (2016) https://doi.org/10.1117/12.2213940

KEYWORDS: Tomography, Coherence (optics), Signal detection, Visualization, 3D image processing, Receptors, Resistance, Biomedical optics, Current controlled current source

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Neutrophils are immune cells that undergo chemotaxis, detecting and migrating towards a chemical signal gradient. Neutrophils actively migrate across epithelial boundaries, interacting with the epithelium to selectively permit passage without compromising the epithelial barrier. In many inflammatory disorders, excessive neutrophil migration can cause damage to the epithelium itself. The signaling pathways and mechanisms that facilitate trans-epithelial migration are not fully characterized. Our laboratory has developed micro-optical coherence tomography (μOCT), which has 2 μm lateral resolution and 1 μm axial resolution. As a high-resolution native contrast modality, μOCT can directly visualize individual neutrophils as they interact with a cell layer cultured on a transwell filter. A chemoattractant can be applied to the apical side of inverted monolayer, and human neutrophils placed in the basolateral compartment, while μOCT captures 3D images of the chemotaxis. μOCT images can also generate quantitative metrics of migration volume to study the dependence of chemotaxis on monolayer cell type, chemoattractant type, and disease state of the neutrophils. For example, a disease known as leukocyte adhesion deficiency (LAD) can be simulated by treating neutrophils with antibodies that interfere with the CD18 receptor, a facilitator of trans-epithelial migration. We conducted a migration study of anti-CD18 treated and control neutrophils using T84 intestinal epithelium as a barrier. After one hour, μOCT time-lapse imaging indicated a strong difference in the fraction of neutrophils that remain attached to the epithelium after migration (0.67 ± 0.12 attached anti-CD18 neutrophils, 0.23 ± 0.08 attached control neutrophils, n = 6, p < 0.05), as well as a modest but non-significant decrease in total migration volume for treated neutrophils. We can now integrate μOCT-derived migration metrics with simultaneously acquired measurements of transepithelial electrical resistance (TEER), a measure of membrane integrity that decreases when neutrophils create openings in the epithelium to permit migration. Preliminary results (n = 2) using real-time TEER measurements indicate that TEER change in anti-CD18 migration (26% at 1 hour) is not lower compared to control (14% at 1 hour), suggesting that the neutrophil-epithelial interaction is not impaired. Combined µOCT+TEER will allow the relationship of neutrophil migration and epithelial interactions to be studied to help uncover the mechanisms of altered neutrophil behavior in patients with inflammatory and immune diseases.

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