The functionality of parenchymal cells is intimately dependent on the cross-talk with stromal cells and with the vasculature, and the precise patterning of these components can be used to promote tissue maturation. A) Centimeter-scale vascularized bone constructs and bioprinted vascularized bone niche. Reproduced with permission.[24] Copyright 2016, National Academy of Sciences. B) Providing a precise 3D patterning of vascular cells within bioprinted filaments was proven beneficial to mimic healthy liver lobules, and enhance expression of cytochromes in hepatocytic cells, when compared to nonorganized mixing of endothelial cells and hepatocytes within the same bioink. Reproduced with permission.[140] Copyright 2018, Wiley-VCH. C) Free-form endothelialized vessels can be obtained via printing with sacrificial gels and further studied to understand angiogenic sprouting in 3D. Reproduced under the terms of the Creative Commons CC-BY 3.0 License (https://creativecommons.org/licenses/by/3.0/).[281] Copyright 2018, The Authors, published by IOPScience.