Modeling the Effects of Protracted Cosmic Radiation in a Human Organ-on-Chip Platform.

Galactic cosmic radiation (GCR) is one of the most serious risks posed to astronauts during missions to the Moon and Mars. Experimental models capable of recapitulating human physiology are critical to understanding the effects of radiation on human organs and developing radioprotective measures against space travel exposures. The effects of systemic radiation are studied using a multi-organ-on-a-chip (multi-OoC) platform containing engineered tissue models of human bone marrow (site of hematopoiesis and acute radiation damage), cardiac muscle (site of chronic radiation damage) and liver (site of metabolism), linked by vascular circulation with an endothelial barrier separating individual tissue chambers from the vascular perfusate. Following protracted neutron radiation, the most damaging radiation component in deep space, a greater deviation of tissue function is observed as compared to the same cumulative dose delivered acutely. Further, by characterizing engineered bone marrow (eBM)-derived immune cells in circulation, 58 unique genes specific to the effects of protracted neutron dosing are identified, as compared to acutely irradiated and healthy tissues. It propose that this bioengineered platform allows studies of human responses to extended radiation exposure in an "astronaut-on-a-chip" model that can inform measures for mitigating cosmic radiation injury.

Strategies for 3D bioprinting of spheroids: A comprehensive review.

Biofabricated tissues have found numerous applications in tissue engineering and regenerative medicine in addition to the promotion of disease modeling and drug development and screening. Although three-dimensional (3D) printing strategies for designing and developing customized tissue constructs have made significant progress, the complexity of innate multicellular tissues hinders the accurate evaluation of physiological responses in vitro. Cellular aggregates, such as spheroids, are 3D structures where multiple types of cells are co-cultured and organized with endogenously secreted extracellular matrix and are designed to recapitulate the key features of native tissues more realistically. 3D Bioprinting has emerged as a crucial tool for positioning of these spheroids to assemble and organize them into physiologically- and histologically-relevant tissues, mimicking their native counterparts. This has triggered the convergence of spheroid fabrication and bioprinting, leading to the investigation of novel engineering methods for successful assembly of spheroids while simultaneously enhancing tissue repair. This review provides an overview of the current state-of-the-art in spheroid bioprinting methods and elucidates the involved technologies, intensively discusses the recent tissue fabrication applications, outlines the crucial properties that influence the bioprinting of these spheroids and bioprinted tissue characteristics, and finally details the current challenges and future perspectives of spheroid bioprinting efforts in the growing field of biofabrication.

Predicting outcomes of oral food challenges by using the allergen-specific IgE-total IgE ratio.

BACKGROUND: Although allergists typically use allergen-specific IgE (sIgE) levels or skin prick test wheal sizes to identify food allergens that may provoke IgE-mediated food-induced allergic reactions, both tests have high rates of false positivity and mislabel patients who are tolerant as allergic to the food allergen. OBJECTIVE: To examine the accuracy of the ratio of sIgE to total IgE ("Ratio") in predicting the outcome of challenges performed to confirm the development of tolerance. METHODS: Medical records of children diagnosed with food allergy who participated in oral food challenge at an allergy outpatient clinic (2009-2013) were reviewed for IgE antifood serology and concomitant oral food challenge outcomes, which were analyzed for associations by using logistic regression models and receiver operator characteristics curves. RESULTS: The Ratio for participants who failed their challenge was higher than the Ratio of those who passed their challenge (failed 1.48% vs passed 0.49%; n = 195). Receiver operator characteristic curves showed that the Ratio was significantly more accurate than sIgE alone in predicting challenge outcome (Ratio 0.69 vs sIgE alone 0.55; P = .03). These trends were mostly associated with more persistent food allergens, such as peanut, tree nuts, shellfish, and seeds (failed 2.18% vs passed 0.41%; n = 93) (Ratio 0.81 vs sIgE alone 0.54; P < .01). CONCLUSION: Our findings suggest that the Ratio is more accurate than sIgE alone in predicting outcomes of challenges performed to confirm the development of tolerance to select food allergens, especially to peanut and tree nuts. The Ratio may be useful in identifying patients most likely to pass oral food challenge.