Friday, 10 August 2007

Xenotransplants - the pig or not the pig

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The scientific community has been in a heated debate about xenotransplants (transplanting pig islets into humans). Although the procedures are showing to be effective - is the insulin secretion entirely pig? Some experts surmise that after the transplants, diabetic patients are actually able to produce some insulin on their own, after all.

The latest press release from Tissera, Inc (an Israeli-based company) made a statement that raises my hopes. It was, "By the fourth month after transplantation, the insulin dose needed to maintain near-normal blood sugar levels decreased by more than 90% in comparison with the insulin dose needed before transplantation, meaning that endogenous insulin production was predominantly responsible for blood sugar control."

The question of the origin of endogenous insulin was addressed by measurement of blood C-peptide. C-peptide splits from insulin and indicates the level of insulin secretion from the patient. C-peptide levels were measured both at baseline and in response to a sugar load, which brings about a rise in blood C-peptide. The measured C-peptide was shown to be predominantly of pig origin. So herein lies my question: is predominantly more than 50%? A type 1 diabetic has undetectable levels of C-peptide. Period. After the xenotransplant the C-peptide level is all of a sudden detectable? Could these islet transplants assist in regenerating the diabetics' own islets?

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