Title : 3D Bio printed cardiovascular tissue model for space based applications
Abstract:
Microgravity is one of the most significant stress factors experienced by living organisms during spaceflight. Controlled in vitro studies of cells and tissues under the conditions of microgravity can improve our understanding of gravity sensing, transduction and responses in living cells and tissues. Cells exposed to microgravity show reorganization of the cytoskeletal system, altered proliferation and increased apoptosis. Most culture systems used to study effects of microgravity are limited by the 2D confines of the culture dish. This limits proliferation and differentiation of cells in 2D which could potentially limit cell-cell interactions that is important for developing the level of organization in tissue obtained in vivo. 3D culture in microgravity can profoundly modulate cell proliferation and survival by allowing cells to self-organize by aggregation and facilitate spatially unrestricted interactions between cells and their surroundings. Research studies have demonstrated that exposure to microgravity in space leads to cardiovascular deconditioning in astronauts by inducing adaptive alterations in vascular structure and function which is measured through cell morphological studies and gene expression. Although microgravity clearly alters gene expression of cells in culture and induces the aggregation of cells into tissue-like structures, each cell appears to have cell-specific responses to microgravity and therefore mechanical characterization is conducted on the 3D bioprinted constructs to assess the contractility of the tissue. This 3D bioprinted tissue model will help in understanding the effects of microgravity on endothelial dysfunction by studying the changes in the 3D construct embedded with endothelial cells, forming the inner wall of the vasculature. An extrusion-based six-head bioprinter (Celllink BioX6) is used for bioprinting tissue constructs. The bioprinted tissue constructs are imaged using fluorescence microscopy to assess cell attachment and cell distribution within the channel. Cellular viability if the bioprinted tissue constructs are assessed using live-dead assay. These bioprinted constructs are finally exposed to 3-D clinostat Gravite microgravity simulator system available at NASA KSC over a period of 24-72 hours. Following exposure, biochemical analysis is performed by measuring the availability of nitric oxide (NO) and reactive oxygen species (ROS) generation and compared with the controls.
