Back to Winter 1999-2000 CivAb                       Home

The same British company, Imutran, a subsidiary of the Swiss firm Novartis, made essentially the same announcement in 1996.  So far, prudence has prevailed, but companies, with an eye on a potential international market estimated to be in the neighborhood of $7 billion, are pushing hard to start partaking of their share of it.

Two other companies, one unnamed as yet, have applied to the British Department of Health to begin xenotransplant trials although not with whole organs in the case of the American firm Genzyme, which wants to transplant brain cells from fetal pigs into human victims of Parkinson's disease.
   
Cells, so small you cannot see them without a good microscope, may sound less dangerous than whole organs, but there is still the possibility, even the likelihood, of transferring unknown pathogens along with them. 

A  study, co-sponsored by Novartis and the US Centers for Disease Control tracked 150 patients in 9 countries who had been exposed to live pig tissue over a 12-year period.  Most, 131, had had their blood circulated through pig spleens, 15 had skin grafts, and 14 had injections of porcine pancreas cells to treat diabetes. (Science, Aug. 21, 1999 as reported in August 23 document of  Campaign for Responsible Transplantation) 

There were reports of rashes and fevers but the most definitive information came from a Russian experiment in which the blood of 30 patients was circulated through pig tissue outside their bodies. Of these 23 still had pig cells circulating in their blood more than eight years later and 4 had produced antibodies against porcine endogenous retrovirus (PERV), indicating an infection. This occurred without  transplanting organs or tissues, just from running blood through pig spleens, kidneys, livers or clumps of cells.

In the late 1980's, (unspecified) doctors achieved  improvement in some Parkinson's patients by implanting neurons from human fetal cells into their brains.  In 1995 the University of Colorado Health Sciences Center observed improved movement in 13 of 19 patients injected with fetal cells compared to no improvement in the placebo group. (Science News, November 27, 1999)

Cell culture holds a lot of promise.  We have seen how cells were cultured to form an ear for a boy born without one.  The latest achievement at Children's Hospital in Boston is growing replacement heart valves starting with cells from a patient's own tissues, thus eliminating the need for immune suppression to avoid rejection.  Unfortunately, the patient in this case was a lamb, who didn't need  valve replacement.  Transplant surgeon Dr Simon Hoerstrup estimates that it will be "several years before they will be ready for tests in humans".  (The Evening Tribune, Nov. 8, 1999  AP report)

The use of embryonic human cells eliminates the danger of pig pathogens causing a new transmissible human disease  The religious conviction of  "pro-lifers" that a clump of cells too small to be seen with the naked eye is a human being rather than living matter with the potential of becoming one if implanted in somebody's womb, has discouraged research in this promising way to help Parkinson's victims.  Perpetuating these cells in cultures could provide an  almost limitless supply for therapeutic uses without the need for fresh cells, which could be then be thrown away again as they are now.

There is also the possibility of using adult stem cells and growing organs from a patient's own cells.  Stem cells have the capacity to develop into other kinds of human cells and could be useful in developing treatments for other human problems without the risk of spawning new diseases and without the risk of tampering with the genes that make one  species distinct from another.