Scientists grow bones,with eye on patients needs

Dr Vunjak-Novakovic and her team have created and nourished two small bones from scratch in their laboratory. The bones,part of a joint at the back of the jaw,were created with human stem cells. The shape is based on digital images of undamaged bones.

Tissue-engineered bones have many implications,according to Dr Charles A Vacanti,director for tissue engineering at the Brigham and Womens Hospital. If your imaging equipment has sufficient high resolution,you can construct virtually any intricate shape you want for example,the middle ear bone,creating an exact duplicate, he said.

Engineered bones are being tested on animals and on a few people,and may be common in operating rooms within a decade,said Rosemarie Hunziker,a program officer at the National Institute of Biomedical Imaging and Bioengineering.

Dr Vunjak-Novakovic,Dr Warren L Grayson and other members of the team used digital images of the joint to guide a machine that carved a three-dimensional replica,called a scaffold,from cleansed bone material. The team turned the bare scaffold into living tissue by putting it into a chamber moulded to its exact shape,and adding human cells,typically isolated from bone marrow or liposuctioned fat. A steady source of oxygen,growth hormones,sugar and other nutrients was piped into the chamber so the bone would flourish.

The cells grow rapidly, Dr Vunjak-Novakovic said. They dont know whether they are in the body or in a culture. Traditional bone grafts are typically harvested from other parts of the body or made of materials like titanium that arent always compatible with host bones or cause inflammation,said Dr Francis Y Lee,a professor of clinical orthopedic surgery. If we have an anatomically matching scaffold that can host bone cells, Dr Lee said,this will provide a new way of reconstructing bone and cartilage defects.