Regenerative medicine is focused on developing and applying new treatments to heal tissues and organs and restore function lost due to aging, disease, damage, or defects. The field of regenerative medicine aims to facilitate the repair or regrowth of damaged tissue or organs. Humans can naturally regenerate some tissues, including the liver, which, if damaged due to disease or injury, can grow back to its original size and function, though not its original shape. Unfortunately, many other human tissues do not regenerate, and a goal in regenerative medicine is to find ways to promote tissue regeneration in the body or to engineer replacement tissues using tissue engineering.