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Next Generation Tissue Engineering Strategies by Combination of Organoid Formation and 3D Bioprinting
Published in Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon, Tissue Engineering Strategies for Organ Regeneration, 2020
Shikha Chawla, Juhi Chakraborty, Sourabh Ghosh
Embryoid bodies are prepared using embryonic stem cells and induced pluripotent cells, using selective cocktails of cytokines. In several cases, preparation of embryoid bodies is a crucial first step in lineage-specific differentiation protocols for stem cells (Brickman and Serup 2017). In this process, relatively large numbers of cells (>1000 to 1 million cells per well) are aggregated, using microwells and hanging drops, and induced to differentiate towards specific cell type. Gradually with increasing culture time, within the embryoid body, differentiated cells seem to assume different morphologies, to develop disorganized cell mass. Reaggregation of embryoid bodies, followed by cellular self-assembly, leads to development of organoids. Recently, self-assembled embryonic stem cells based organoid formation has been acknowledged as one of the key in vitro methods to generate mini organs like mini-gut, brain-like organoids (Warmflash et al. 2014) and liver organoids (Takebe et al. 2013) etc. Morphogen signaling gradient plays a critical role in positioning and patterning of the whole embryos and tissues during normal development, leading to final body parts compartmentalization. Thus, quest for modalities to include combination of cytokines to reproduce such embryonic development based on spatio-temporal morphogen signaling is the need of current developmental biology inspired tissue engineering. Apart from cellular self-assembly tissue, organ formation may involve other complex phenomenon, for instance, varied affinity amongst distinct elements (expression of hemophilic or heterophilic adhesion molecules), hypoxia or mass transport issues, cellular rearrangements and active cell migration. Several organoid formation strategies have been utilized in the past to develop mini-organs. Few examples include the development of two layered optic cup-like organoid using 3D aggregates of self-assembled mouse pluripotent embryonic stem cells (Eiraku et al. 2011). Nelson et al. developed a 3D in vitro model of mouse mammary epithelial tubules; they utilized micropatterning technology to guide the 3D structure of the developed organoid. They successfully demonstrated that the geometry of multicellular tubules, in addition to the availability of the spatially controlled levels of autocrine inhibitory morphogen concentration, can regulate the branch positioning during mammary epithelial cells and primary organoids morphogenesis (Nelson et al. 2006). Another interesting example of morphogen induced control of organoid formation was demonstrated by Montesano et al. (Montesano et al. 1991). Using 3D culture of Madin–Darby canine kidney cells, Montesano et al. demonstrated voluntary tubular formation from the epithelial cyst in the presence of hepatocyte growth factor. Thus, conclusively, developmental biology inspired morphogen signaling in 3D organoids tissue and organ is a promising approach for developing tissue-engineered equivalents (Fig. 4.2). It is pertinent to mention here that since this strategy is scaffold/biomaterial-free, there is no concern how polymer/biomaterial will change cell behavior and thus may closely mimic the in vivo like self-driven cellular/tissue morphogenesis.
Ambient hydrogen sulfide exposure increases the severity of influenza A virus infection in swine
Published in Archives of Environmental & Occupational Health, 2021
Cristina M. Santana, Phillip Gauger, Amber Vetger, Drew Magstadt, Dong-Suk Kim, Denusha Shrestha, Chandrashekhar Charavaryamath, Wilson K. Rumbeiha
Pigs were challenged with A/Swine/Missouri/73632LG/2014 H3N2. The IAV isolate was propagated in Madin-Darby Canine Kidney Cells (MDCK) as previously described [22]. At DPI 0, pigs were anesthetized and simultaneously inoculated with 2 ml intratracheally and 1 ml intranasally of 1 × 105.0 TCID50/ml. Non-challenge groups were inoculated with the same volumes of a placebo (cell culture medium, MEM, Thermofisher Scientific). This viral dosage was chosen from experience in our laboratory and is consistent with previous studies [23, 24].