Biomedical Applications of Tissue Clearing and Three-Dimensional Imaging in Health and Disease

Abstract

Summary Three-dimensional (3D) optical imaging techniques can expand our knowledge about physiological and pathological processes that cannot be fully understood with 2D approaches. Standard diagnostic tests frequently are not sufficient to unequivocally determine the presence of a pathological condition. Whole-organ optical imaging requires tissue transparency, which can be achieved by using tissue clearing procedures enabling deeper image acquisition and therefore making possible the analysis of large-scale biological tissue samples. Here, we review currently available clearing agents, methods, and their application in imaging of physiological or pathological conditions in different animal and human organs. We also compare different optical tissue clearing methods discussing their advantages and disadvantages and review the use of different 3D imaging techniques for the visualization and image acquisition of cleared tissues. The use of optical tissue clearing resources for large-scale biological tissues 3D imaging paves the way for future applications in translational and clinical research.

Lung organoids: advances in generation and 3D-visualization

“…The complexity and delicate structure of the lung are primary reasons why acquiring high-quality microscopy images is difficult, particularly three-dimensional (3D) imaging of the lung for studies that require subcellular resolution while maintaining anatomical structure. Over the last decade, cutting-edge microscopic and quantitative histological techniques have been developed for 3D imaging of lung tissue (reviewed in (Schittny 2018)) and, although innovations have been made with regard to lung tissue clearing and preparation, the acquisition of highquality, clinically relevant data for 3D imaging remains challenging (Gomez-Gaviro et al 2020;Klouda et al 2020).…”

A Review of Ex Vivo X-ray Microfocus Computed Tomography-Based Characterization of the Cardiovascular System

“…However, it results in the destruction of the sample, preventing further analysis, and the 3D reconstruction of the tissue requires image stacking and is highly labor-intensive. Moreover, it renders an anisotropic resolution; it is prone to artefacts and the sample preparation (fixation, embedding and cutting) can potentially alter the structural organization of the tissue [ 16 , 17 , 18 ]. Episcopic microscopy has already reduced some of the drawbacks of standard histology by automatically aligning the images of paraffin-embedded samples during sectioning, making the 3D reconstruction easier, but it does not prevent the destruction of the sample and still renders an anisotropic resolution [ 19 ].…”

A quick and versatile protocol for the 3D visualization of transgene expression across the whole body of larval Drosophila

“…In the present study we have developed a clearing protocol tailored specifically to third-instar larvae, user friendliness, and routine use. Important features of the present procedure include a brief initial incubation with fresh bleach, making the enzymatic digestion of the exoskeleton unnecessary (Masselink et al, 2019;Pende et al, 2018), and the use of ECi (Klingberg et al, 2017) instead of more toxic agents such as DBE or THF (Erturk et al, 2012) or hydrophilic reagents (Ueda et al, 2020;G omez-Gaviro, Sanderson, Ripoll, & Desco, 2020). ECi is not only a budget compound and approved as non-toxic.…”