18 October 2009
ByAppeared in BioNews 530
Tissue-engineers at Columbia University, New York, US, have grown a jawbone from bone stem cells in the laboratory for the first time. The team, led by Dr Gordana Vunjak-Novakovic, published their work in the journal Proceedings of the National Academy of Sciences. The result marks a milestone in the move towards bone reconstructions - from patients' own stem cells - for those affected by congenital defects, arthritis or cancer resections.
The team chose the jawbone, or temporomandibular joint (TMJ), to carry out a 'proof of concept' study, as it is one of the most complex joints in the body and represents a substantial challenge to model from scratch. 'We thought the jawbone would be the most rigorous test of our technique; if you can make this, you can make any shape', commented Dr Vunjak-Novakovic.
First, a scaffold was made form 'trabecular bone' - the porous, spongy structure found in the centre of bones - and infused with human mesenchymal stem cells (hMSCs) and all the nutrients needed for a bone to form. The scaffold, based on digital images of patient jawbones, was placed within a custom made 'bioreactor', designed to precisely resemble a human jawbone.
After five weeks, layers of bone-like tissue became visible. The tissue was physiologically realistic, the paper says. Yet the structure contained only bone cells - no cartilage, tendons or blood vessels were grown. The team is currently working on ways to make a hybrid structure, connectable to blood vessels in the head.
Professor Anthony Hollander, a tissue engineering expert from the University of Bristol who contributed to the production of an artificial windpipe last year, said: 'One of the major problems facing scientists in this field is how to engineer a piece of bone with the right dimensions - that is critical for some of these bone defects'.
Other recent achievments in the field of tissue regeneration include the use of pluripotent stem cells to create an artificial bladder and a beating heart in the laboratory, and scientists at Tokyo University earlier this year demonstrated the growth of teeth in mice.