Ultra-High-Resolution 3D Optical Coherence Tomography Reveals Inner Structures of Human Placenta-Derived Trophoblast Organoids.

Abigail J Deloria,Victoria Kunihs,Simon Oberhofer,Wolfgang Drexler,Rainer Leitgeb,Sandra Haider,Richard Haindl,Bianca Dietrich,Mengyang Liu,Martin Knofler

doi:10.1109/tbme.2020.3038466

Abigail J Deloria, Victoria Kunihs + Show 8 more

Open Access

https://doi.org/10.1109/tbme.2020.3038466

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Abstract

3D optical coherence tomography (OCT) is used for analyses of human placenta organoids in situ without sample preparation. The trophoblast organoids analyzed were derived from primary human trophoblast. In this study a custom made ultra-high-resolution spectral domain OCT system with uniform spatial and axial resolution of 2.48μm in organoid tissue was used. The obtained OCT results align to differentiation status tested via quantitative polymerase chain reaction, Western blot analyses, immunohistochemistry, and immunofluorescence of histological sections. 3D OCT enables a more detailed placenta organoid monitoring compared to brightfield microscopy. Inner architecture with light scattering "bridges" surrounding cavities were visualized and quantified in situ for the first time. The formation of these bridges and cavities is congruent to differentiated trophoblast organoids having developed syncytiotrophoblasts. Using 3D OCT in living placenta organoids is a fast tool to assess the differentiation status and resolve internal structures in situ, which is not possible with standard live cell imaging modality. Only recently human placenta-derived organoids were established, allowing to have a highly reproducible and stable in vitro model to investigate not only developmental but also physiological and pathophysiological processes during early pregnancy. To our knowledge, this work is the first to analyze living human placenta organoids using 3D OCT. Thereby, the rapid and especially non-endpoint OCT qualitative analyses align to the differentiation stage of organoids, which will aid future advancement in this field.

Highlights

C ELL culture is an indispensable preclinical model system to study physiological events, disease, and drug discovery
We compared the images of the same living, in GRFM embedded Trophoblast organoids (TB-ORGs) via two in situ imaging techniques, brightfield microscopy using the EVOS FL Cell Imaging System microscope (Fig. 1a) and a customized optical coherence tomography (OCT) system (Fig. 1b–d), respectively
To investigate wether OCT and brightfield imaging techniques were in quantitative agreement, TB-ORG areas of brightfield and en face avaraged OCT images of 9 organoids were measured via ImageJ by three raters three times and compared

Summary

Introduction

C ELL culture is an indispensable preclinical model system to study physiological events, disease, and drug discovery. Organoids are formed by stem or progenitor cells, that give rise to complex, self-organizing, and self-renewing 3D cell culture systems embedded in a matrix-gel recapitulating more closely features of in vivo organs [5]–[7]. Self-renewing placenta organoids, derived from isolated trophoblasts of first trimester placentae, were developed and are used as a model system for the early human placenta [10], [11]. These works set the fundament to elucidate physiological and pathophysiological processes aiming for placental disease modeling and fetal-maternal interaction during placentation.

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