Rapid production of human liver scaffolds for functional tissue engineering by high shear stress oscillation-decellularization

The development of human liver scaffolds retaining their 3-dimensional structure and extra-cellular matrix (ECM) composition is essential for the advancement of liver tissue engineering. We report the design and validation of a new methodology for the rapid and accurate production of human acellular liver tissue cubes (ALTCs) using normal liver tissue unsuitable for transplantation. The application of high shear stress is a key methodological determinant accelerating the process of tissue decellularization while maintaining ECM protein composition, 3D-architecture and physico-chemical properties of the native tissue. ALTCs were engineered with human parenchymal and non-parenchymal liver cell lines (HepG2 and LX2 cells, respectively), human umbilical vein endothelial cells (HUVEC), as well as primary human hepatocytes and hepatic stellate cells. Both parenchymal and non-parenchymal liver cells grown in ALTCs exhibited markedly different gene expression when compared to standard 2D cell cultures. Remarkably, HUVEC cells naturally migrated in the ECM scaffold and spontaneously repopulated the lining of decellularized vessels. The metabolic function and protein synthesis of engineered liver scaffolds with human primary hepatocytes reseeded under dynamic conditions were maintained. These results provide a solid basis for the establishment of effective protocols aimed at recreating human liver tissue in vitro

Mesenchymal stromal cells mediate Aspergillus hyphal extract-induced allergic airway inflammation by inhibition of the Th17 signaling pathway

Systemic administration of mesenchymal stromal cells (MSCs) suppresses airway inflammation and methacholine-induced airway hyper-responsiveness (AHR) in mouse models of T helper cell (Th) type 2-mediated eosinophilic allergic airway inflammation (AAI); however, the efficacy of MSCs in mouse models of severe Th17-mediated neutrophilic AAI has not yet been demonstrated. We assessed MSC effects in a mouse model of mixed Th2/Th17 AAI produced by mucosal exposure to Aspergillus fumigatus hyphal extract (AHE). Following sensitization produced by oropharyngeal AHE administration, systemic (tail vein) administration of syngeneic MSCs on the first day of challenge significantly reduced acute AHR predominantly through reduction of Th17-mediated airway inflammation. In parallel experiments, MSCs also mitigated AHR when administered during recurrent challenge 10 weeks after initial sensitization and challenge through reduction in systemic Th17-mediated inflammation. Investigation into potential mechanistic actions of MSCs in this model demonstrated that although T regulatory cells were increased in all AHE-treated mice, MSC administration did not alter T regulatory cell numbers in either the acute or recurrent model. Differential induction of interleukin-17a secretion was observed in ex vivo restimulation of mediastinal lymph node mixed-cell cytokine analyses. Although the mechanisms by which MSCs act to decrease inflammation and AHR in this model are not yet fully elucidated, decrease in Th17-mediated airway inflammation appears to play a significant role. These results provide a basis for further investigations of MSC administration as a potential therapeutic approach for severe refractory neutrophilic asthma