Researchers Develop New 3D Imaging Method as a More Cost-Effective, Accurate Way to Visualize Cells in Tumors

Advanced 3D imaging has been used often in the medical field, for applications as varied as to study the internal body structure of humans, prove if genes can influence our facial appearance, and even provide earlier breast cancer detection. A team of researchers with the National Institute of Allergy and Infectious Diseases (NIAID), one of the National Institutes of Health (NIH), have been hard at work developing a new, detailed method of 3D visualizing how cell types are distributed in complex tissues, such as tumors, called Clearing-Enhanced 3D microscopy (C_e3D).

Chemical tissue clearing techniques are used by hospital laboratories and researchers to make dense, opaque tissue transparent when they need detailed images of tissue samples, especially from tumor cells, which then lets scientists use state-of-the-art microscopes to identify and figure out the distribution of certain cells that could be cancerous and have already been marked with easy-to-see antibodies or fluorescent compounds. However, current tissue clearing techniques are limited and hard to use, so researchers have a difficult time understanding how a patient’s immune system is affecting the tumor. Some scientists use methods other than tissue clearing to count the cell types in tissues, but these techniques mean grinding up or slicing the tissue samples.

This new 3D tissue imaging technique could help medical researchers provide evaluations of how well various immunotherapies are targeting complex cancers. By using C_e3D, researchers are able to keep the biopsied tissue in one piece, use tracking methods to mark many different cell types, and then view the results in accurate 3D.

Ce3D allows scientists to “clear” tissues for easier analysis.

Ronald N. Germain, MD, PhD, and chief of the Laboratory of Systems Biology in NIAID’s Division of Intramural Research, together with Weizhe Li, PhD, also from NIAID’s Laboratory of Systems Biology and Michael Y. Gerner, PhD, with the University of Washington’s Department of Immunology, published a paper on their findings, titled “Multiplex, quantitative cellular analysis in large tissue volumes with clearing-enhanced 3D microscopy (C_e3D),” in Proceedings of the National Academy of Sciences.

The abstract reads, “Organ homeostasis, cellular differentiation, signal relay, and in situ function all depend on the spatial organization of cells in complex tissues. For this reason, comprehensive, high-resolution mapping of cell positioning, phenotypic identity, and functional state in the context of macroscale tissue structure is critical to a deeper understanding of diverse biological processes. Here we report an easy to use method, clearing-enhanced 3D (C_e3D), which generates excellent tissue transparency for most organs, preserves cellular morphology and protein fluorescence, and is robustly compatible with antibody-based immunolabeling. This enhanced signal quality and capacity for extensive probe multiplexing permits quantitative analysis of distinct, highly intermixed cell populations in intact C_e3D-treated tissues via 3D histo-cytometry. We use this technology to demonstrate large-volume, high-resolution microscopy of diverse cell types in lymphoid and nonlymphoid organs, as well as to perform quantitative analysis of the composition and tissue distribution of multiple cell populations in lymphoid tissues. Combined with histo-cytometry, C_e3D provides a comprehensive strategy for volumetric quantitative imaging and analysis that bridges the gap between conventional section imaging and disassociation-based techniques.”

Ce3D imaging allows scientists to view multiple cell types, shown here marked with assorted colors, that make up complex tissues like this lymph node in three dimensions.

In order to find the correct combination for the C_e3D method, the research team screened different reagants, using the lymphoid tissues of mice, because the level of detail and complexity in the tissue is high enough for the researchers to “accurately interpret how this tissue responds to medication and immunotherapy.”

Once they had the proper combination, they also tested the method on tissue from the intestine, liver, lung, muscle, and thymus, and were able to get detailed, comprehensive 3D images of each.

The medical field, in terms of cancerous growths, is turning more and more frequently these days to responses that are tailored to individual tumors. NIAID’s new C_e3D method could prove very important for researchers who are working to evaluate therapies in the lab, and for doctors evaluating real patients, as it’s a very sophisticated technique to get detailed information about a tumor. In addition, the technique is more scalable and cost-effective than tissue clearing methods, as it uses existing laboratory instruments and less expensive substances. Discuss in the 3D Tissue Imaging forum at 3DPB.com.