WOW!! This is big news, also quite odd. But the implications here are enormous. This means that eventually for leukemia patients. You can grow your own bone and get your own bone marrow for a bone marrow transplant.
IF a lover breaks your heart, tissue engineers can’t fix it. But if sticks and stones break your bones, scientists may be able to grow custom-size replacements.
Gordana Vunjak-Novakovic, a professor of biomedical engineering atColumbia University, has solved one of many problems on the way to successful bone implants: how to grow new bones in the anatomical shape of the original.
Dr. Vunjak-Novakovic and her research team have created and nourished two small bones from scratch in their laboratory. The new 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 a leading figure in the field, Dr. Charles A. Vacanti, director of the laboratories for tissue engineering and regenerative medicine at the Brigham and Women’s Hospital in Boston. He has no connection to the Columbia work. “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. “It’s a splendid example of tissue engineering at its best.”
Engineered bones are being tested in animals and in a few people, and may be common in operating rooms within a decade, said Rosemarie Hunziker, a program officer at theNational Institute of Biomedical Imaging and Bioengineering, which sponsors research in the field, including that at Columbia.
“It’s a field that is attracting much interest from venture capitalists,” said Robert Langer, a professor at M.I.T. Dr. Langer has more than 750 patents issued or pending in tissue engineering and drug delivery systems, and is an adviser to many companies that have started businesses based on his work.
Scott Hollister, a professor at the University of Michigan, Ann Arbor, is a co-founder of Tissue Regeneration Systems, a company that is commercializing technology his group is developing for skeletal reconstruction in the face, spine and extremities.
Dr. Vunjak-Novakovic, who has filed a patent application through Columbia, said that her lab’s work had attracted considerable interest from investors, but that it was too soon to talk about commercial applications. “We are starting studies with large animals that will establish safety and feasibility before commercialization, “she said.
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 molded 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, or bioreactor, sothe bone would flourish.
“The cells grow rapidly,” Dr. Vunjak-Novakovic said. “They don’t know whether they are in the body or in a culture. They only sense the signals.”
Traditional bone grafts are typically harvested from other parts of the body, often a traumatic step, or made of materials like titanium that aren’t always compatible with host bones or cause inflammation, said Dr. Francis Y. Lee, a professor of clinical orthopedic surgery at Columbia’s College of Physicians and Surgeons. Dr. Lee also has no connection to Dr. Vunjak-Novakovic’s work.
“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.”
The design of the bioreactor is ingenious, said Dr. Vacanti of Boston, because it allows sources of nourishment and other fluids to permeate the pores of the scaffold as new bone grows within the pores. Often, cells make tissue mainly on the outside of a scaffold, while cells inside tend to die. But Dr. Vunjak-Novakovic’s bioreactor permits close observation and control of additives by the research team. “They can direct the flow and monitor the effect on the development of tissue,” Dr. Vacanti said.
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