Friday, November 21, 2008

A New Era in Transplant Medicine and Tissue Engineering

A recently performed medical procedure performed by Spanish doctors successfully replaced a damaged trachea. Will the “Holy Grail” of tissue engineering – replacing whole organs – be that much closer?

By: Vanessa Uy

Doctors in Spain recently replaced one of the windpipes or trachea of 30-year-old Claudia Castillo after a bout with tuberculosis damaged the organ. What made the procedure unique is that the donated trachea came from a non-genetically compatible donor. Plus, the new procedure made the use of post-operative anti-rejection drugs unnecessary by making the donated organ acquire an all-out total histocompatibility with the recipient.

The uniqueness of this new medical procedure involves the use of the recipient’s own stem cells to make the donated organ rejection-proof, even if it came from a non-compatible donor. The new procedure involved a trachea obtained from a recently deceased organ donor. The donated trachea is then cleansed of the donor’s own genetic material until all that is left is just a collagen scaffold of a trachea. The next step involved infusing the donated trachea collagen scaffold with Claudia Castillo’s own stem cells to make the donated trachea both immunologically and genetically compatible – total histocompatibility - with her own body.

This cutting-edge medical procedure was made possible due to a collaboration of three doctors from Spain, Britain, and Italy. At present, this new medical procedure is still prohibitively expensive to be done on a routine basis. But the success of this particular trial serves as a proof of concept that stem-cell therapy works in increasing transplanted organ’s histocompatibility with their recipients and is now more than a mere laboratory curiosity.

Even though this newfangled medical procedure is seen by everyone as the newest and latest in medical science, it can trace it’s roots back to more than 40 years of laboratory research. Back in 1965, Marshall R. Urist of the University of California at Los Angeles probably kicked-off the science of tissue engineering – creating semi-synthetic living organs that can be used as human replacement parts – by demonstrating that new bony tissue would form in test animals that received implants of powdered bone. Fast forward to 2006, a team of American doctors successfully “created” a human bladder by growing the organ out of stem cells - which can be very useful in treating urinary incontinence of the elderly and bladder reflux in children without the need of post-operative anti-rejection drugs and their negative side-effects.

Before receiving the life-saving tracheal transplant, Claudia Castillo was often out of breath due to her tuberculosis damaged left trachea, if left untreated, her left might become disease becoming withered and then die off. The new procedure that gave Claudia Castillo the genetically compatible trachea really did suit her particular case. If she had undergone a “conventional” tracheal transplant procedure, it might have necessitated the use of anti-rejection medication. Anti-rejection medication would have been the last thing she needs because these drugs are notorious for wrecking havoc with the human immune system. Thus making her susceptible with diseases that attack people with weakened immune systems like tuberculosis, which was the root cause of Claudia Castillo’s problem in the first place. Worse still, she might contract pneumonia, which often happens to patients taking anti-rejection medication. But thanks to this new medical procedure, those worries are behind her or the next patient who undergoes this procedure. This truly is the new era of transplant medicine and tissue engineering. The next step now is to make the procedure much cheaper than what it current costs so that more people that badly needed it can avail of this particular procedure without going bankrupt.

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