Mapping the thymus in the viscoelastic landscape of biological tissues

The thymus plays a pivotal role in the generation of immunocompetent T cells. Although its function is dependent on its complex extracellular matrix, to date, the organization of its 3D architecture and mechanical properties have been poorly investigated. This hampers efforts to model and engineer this organ, which is a critical step for the development and application of strategies for the treatment of many haematological and autoimmune diseases. Here, we provide the first comprehensive dataset on thymic viscoelasticity and extracellular matrix architecture across scales and propose a novel visualization strategy — adapted from Ashby plots in materials science — to map and compare tissue mechanics among organs in a clear, interpretable format. The viscoelastic properties are represented by performance indicators which define the tendency of tissues to manifest solid- or a liquid-like behaviour. The Ashby-inspired plots are a unifying framework for visualizing tissue mechanics across systems. They indicate where the thymus “sits” among other organs and highlight its compliant and dissipative nature with respect to other soft biological tissues.