A team of Massachusetts General Hospital (MGH) investigators has made the first steps towards development of bioartificial replacement limbs suitable for transplantation. In their report, which has been published online in the journal Biomaterials, the researchers describe using an experimental approach previously used to build bioartificial organs to engineer rat forelimbs with functioning vascular and muscle tissue. They also provided evidence that the same approach could be applied to the limbs of primates.
They have shown that they can maintain the matrix of all of these tissues (muscles, bone, cartilage, blood vessels, tendons, ligaments and nerves) in their natural relationships to each other, that they can culture the entire construct over prolonged periods of time, and that we can repopulate the vascular system and musculature.”
The authors note that more than 1.5 million individuals in the U.S. have lost a limb, and although prosthetic technology has greatly advanced, the devices still have many limitations in terms of both function and appearance.
They had used decellularization technique to regenerate kidneys, livers, hearts and lungs from animal models, but this is the first reported use to engineer the more complex tissues of a bioartificial limb.
The same decellularization process used in the whole-organ studies – perfusing a detergent solution through the vascular system – was used to strip all cellular materials from forelimbs removed from deceased rats in a way that preserved the primary vasculature and nerve matrix. After thorough removal of cellular debris – a process that took a week – what remained was the cell-free matrix that provides structure to all of a limb’s composite tissues. At the same time, populations of muscle and vascular cells were being grown in culture.
* The secret to building a living, functioning, artificial limb starts with a dead one.
* Over a period of 52 hours, infusion of a detergent solution removes cells from a rat forelimb, leaving behind the cell-free matrix scaffolding onto which new tissues can be regenerated.
* it is put in a specially designed bioreactor and after 2 weeks it is recellularized
* they graft some skin onto the fledgling leg, and the doctors had themselves their own, home-grown rat limb (minus the bones and cartilage).
* they attached it to a rat
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