Scientists are taking the first steps to see if organs like hearts or livers can be grown inside the human body using a new tissue replacement technique, a bio-engineering company said Tuesday. The Massachusetts Institute of Technology and the Childrens' Hospital of Boston were granted three patents covering the growth of new organs and tissue within the body.The patents are licensed to La Jolla, Calif.-based Advanced Tissue Sciences Inc., which owns related patents. The company said the technology has already been used to grow new livers in rats and dogs and also to generate new heart muscles in animals with diseased hearts.