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INTRODUCTION: This talk will discuss the applications of tissue engineering in two areas of medicine: regenerative engineering of whole organs at the clinical scale, and modelling of diseases and therapeutic modalities using microsized “organs on chip” platforms. EXPERIMENTAL: Engineering of human tissues involves the use of human stem cells (in most cases derived from a sample of blood) and two engineering components that are “instructing” the cells how to form a specific tissue. Th first component is a tissue specific biomaterial scaffold that serves as a structural and logistic template for tissue formation. The second component is the bioreactor designed to provide homeostasis and tissue-specific molecular and physical regulatory factors, as well as sensing and imaging modalities necessary to monitor and measure tissue development and function. In all cases, we aim to recapitulate the cell niches, using bioengineering tools. RESULTS AND DISCUSSION: To illustrate the state of the art in the field and reflect on the current challenges and opportunities, this talk will discuss representative examples of whole organ engineering and organs-on chip models of injury, disease and regeneration. At the clinical scale, the goal is to achieve regeneration by treating the whole organ damaged by injury of disease. We will discuss regenerative engineering of a joint (that can be engineered de novo), and the lung and heart (that are being regenerated with the use of therapeutic cells). In organs-on-chip platforms, microsized human tissues are matured to adult-like phenotypes and functionally linked by vascular perfusion containing circulating cells and factors. At the micro-scale, we will focus on organs on chip models of cancer metastasis, radiation damage, and side effects of some common drugs. Finally, we will discuss the key challenges the field is currently facing. CONCLUSIONS: Tissue engineering is increasingly successful in recapitulating human physiology in health and disease, in patient-specific settings, supporting the development of high-fidelity research models and treatment modalities tailored to the specific patient. [ABSTRACT FROM AUTHOR]

Cosmic radiation is the most serious risk that will be encountered during the planned missions to the Moon and Mars. There is a compelling need to understand the effects, safety thresholds, and mechanisms of radiation damage in human tissues, in order to develop measures for radiation protection during extended space travel. As animal models fail to recapitulate the molecular changes in astronauts, engineered human tissues and "organs-on-chips" are valuable tools for studying effects of radiation in vitro. We have developed a bioengineered tissue platform for studying radiation damage in individualized settings. To demonstrate its utility, we determined the effects of radiation using engineered models of two human tissues known to be radiosensitive: engineered cardiac tissues (eCT, a target of chronic radiation damage) and engineered bone marrow (eBM, a target of acute radiation damage). We report the effects of high-dose neutrons, a proxy for simulated galactic cosmic rays, on the expression of key genes implicated in tissue responses to ionizing radiation, phenotypic and functional changes in both tissues, and proof-of-principle application of radioprotective agents. We further determined the extent of inflammatory, oxidative stress, and matrix remodeling gene expression changes, and found that these changes were associated with an early hypertrophic phenotype in eCT and myeloid skewing in eBM. We propose that individualized models of human tissues have potential to provide insights into the effects and mechanisms of radiation during deep-space missions and allow testing of radioprotective measures. One Sentence Summary: Engineered human tissue models can be used to study and counter the effects of cosmic radiation. [ABSTRACT FROM AUTHOR]