About this Research Topic
Epithelial tissues cover all body surfaces and cavities, lining most major organs. One of their main functions is being the first line of body protection against external insults by forming tight, highly selective physical barriers. Most epithelial tissues are multicellular, and the specific cell types are exquisitely arranged in a compartmentalized manner along complex three-dimensional (3D) structures such as invaginations, evaginations, cysts and tubules. Some examples are the intestinal crypts, the gastric glands, the corneal limbus and the hair-follicle bulges. Such 3D architectures are highly relevant for the functionality of the organ and get altered in pathological conditions.
Recent advances in cell biology and engineering techniques have produced major breakthroughs in the field, unraveling a new potential for in vitro models that had traditionally relied on transformed cell lines grown as monolayers. On one hand, novel cell-based systems such as organoids provide 3D miniaturized versions of epithelia that recapitulate major cell types, cell organization and barrier function. On the other hand, technological advances in biofabrication techniques, microfluidics, biomaterials and biosensors, have resulted in microphysiological systems such as organ-on-chip devices, able to mimic tissue functions. Finally, new biomaterials and biofabrication techniques lead to engineered tissues that include non-epithelial components, such as fibroblasts, immune or endothelial cells. It is expected that combinations of these cellular and engineered elements will provide in vitro models of epithelial tissues that might complement some in vivo animal research in preclinical assays. In addition, current developments to stablish patient-derived bioengineered 3D culture models are great tools for in vitro disease modeling and pave the way to personalized and regenerative medicine applications. Still, issues such as standardization, high-throughput, user-friendly setups and the necessary trade-off between complexity and manageability are yet to be defined.
This Research Topic aims to highlight recent experimental approaches to better mimic in vitro the 3D physiology and barrier properties of the different epithelial tissues. It will welcome original research articles and reviews in, but not limited to, areas including:
· epithelial organoids for in vitro assays
· organ-on-chip devices of epithelial tissues
· 3D microengineered models of epithelial tissues
· models including non-epithelial components
· biomedical applications, standardization and critical needs in the field.
Keywords: epithelium, 3D cell culture models, organoids, organ-on-a-chip, microengineered tissues
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