text: A natural ECM scaffold provides the necessary physical and biochemical environment to facilitate the growth and specialization of potent progenitor and stem cells.  Acellular matrices have been isolated in vitro and in vivo in a number of different tissues and organs. Decellularized ECM can be used to prepare bio-ink for 3D bioprinting. The most applicable success from decellularized tissues has come from symmetrical tissues that have less specialization, such as bone and dermal grafts; however, research and success are ongoing at the organ level.
  Acellular dermal matrices have been successful in a number of different applications. For example, skin grafts are used in cosmetic surgery and burn care.  The decellularized skin graft provides mechanical support to the damaged area while supporting the development of host-derived connective tissue. Cardiac tissue has clinical success in developing human valves from natural ECM matrices. A technique known as the Ross procedure uses an acellular heart valve to replace a defective valve, allowing native cells to repopulate a newly functioning valve. Decellularized allografts have been critical in bone grafts that function in bone reconstruction and replacing of deformed bones in patients.
  The limits to myocardial tissue engineering come from the ability to immediately perfuse and seed and implemented heart into a patient. Though the ECM scaffold maintains the protein and growth factors of the natural tissue, the molecular level specialization has not yet been harnessed by researchers using decellularized heart scaffolds. Better success at using a whole organ from decellularization techniques has been found in pulmonary research. Scientists have been able to regenerate whole lungs in vitro from rat lungs using perfusion-decellularization. By seeding the matrix with fetal rat lung cells, a functioning lung was produced.  The in vitro-produced lung was successfully implemented into a rat, which attests to the possibilities of translating an in vitro produced organ into a patient.
  Other success for decellularization has been found in small intestinal submucosa (SIS), renal, hepatic, and pancreatic engineering. Because it is a thin material, the SIS matrix can be decellularized through immersing the tissue in chemical and enzymatic treatments. Renal tissue engineering is still developing, but cadaveric kidney matrices have been able to support development of potent fetal kidney cells. Pancreatic engineering is a testament to the molecular specificity of organs. Scientists have not yet been able to produce an entirely functioning pancreas, but they have had success in producing an organ that functions at specific segments. For example, diabetes in rats was shown to decrease by seeding a pancreatic matrix at specific sites. The future applications of decellularized tissue matrix is still being discovered and is considered one of the most hopeful areas in regenerative research.