A:From the late 1990s, it has been reported that human decellularized tissue-extracellular matrix from which cellular components have been removed-works well as a substitute for living tissue. Decellularized tissue exhibits good biocompatibility, and the lack of donor cellular material minimizes the risk of graft rejection. Importantly, the removal of donor ellular material may allow for the use of animal tissue as a source for xenotransplantation into humans, so this technology has the potential to provide a high-performance scaffold for tissue engineering.

A:The main existing approach for decellularizing tissues involves using detergents. Such techniques may leave residual cytotoxic chemicals or change the mechanical properties of the tissue. We developed an alternative method of decellularizing tissues using highhydrostatic pressure (HHP, >600 MPa). The cell debris can then be removed by washing, without chemicals or detergents.

A: In vivo grafts of HHP-decellularized tissues show minimal inflammation and exhibit good long-term stability. Grafted decellularized tissues can also strongly recruit host cells, facilitating rapid integration into host tissue. An additional benefit is that HHP has a sterilizing effect: Because the treatment disrupts lipid bilayers, it can destroy pathogens such as bacteria, fungi, and some viruses.

A: We transplanted decellularized porcine corneas into rabbits, and achieved transparent corneas that lasted for at least twelve months after transplantation.

Another challenge we tackled was developing graft materials that can function as an interface between hard and soft tissues. We have used decellularized tissues in conjunction with a synthetic polymer to develop a hybrid biomaterial. This material can function s an interface between different tissue types, or between a tissue and an implanted synthetic device.

We also explored using powders made from decellularized tissues for treating myocardial infarction in a rat model. Decellularized liver powder promoted cell integration and neovascularization both in vitro and in vivo, and suppressed myocardial necrosis.

A: We are working on regenerating bone marrow, brain, and cartilage using the relevant decellularized tissues. Decellularized tissue is emerging as superior to many artificial materials currently used in tissue engineering. We will continue working with our research partners to explore the potential of decellularized tissue.