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Pig Breeding Boosted for Transplant Tissue

by 5m Editor
23 July 2008, at 3:10pm

NEW ZEALAND - An entrepreneur of biotechnology, seeking ministerial approval of Auckland experiments to implant pig tissues in diabetes patients, is ramping up its production of piglets to kill for transplant tissue.

Pigs isolated from contact with other pigs for over 150 years on the Auckland Islands are used by Living Cell Technologies (LCT) to produce the islet cells, which can manufacture insulin in humans.

The Rare Breeds Conservation Society recovered 17 pigs from the Auckland Islands in 1999, and some years later descendents were put into quarantine by LCT, which has about 60 in two herds at Invercargill and Auckland.

LCT chief executive Dr Paul Tan claimed last year they were the most disease-free population of pigs in the world, and said he was investigating the possibility of a $6 million pig quarantine and research centre in Southland.

He said that Russian trials of the xenotransplantation technology had been so encouraging the company was expanding its piggeries.

"Positive clinical results have prompted us to expand our pig breeding facilities to meet supplies of DiabeCell for advancing our clinical and commercial programmes internationally," he said in a statement.

LCT last year originally planned to start New Zealand trials late last year but is still waiting on a national advisory committee to report to Health Minister David Cunliffe by August 8.

It has released interim results describing clinical benefits in Russian patients, at the Sklifosovsky Institute.

An initial five type 1 diabetes patients were implanted with the company's DiabeCell, encapsulated porcine islet cells, each receiving the lowest dose.

Two of those patients had received a second, similar, implant and the company said so far "no remarkable adverse events have occurred".

Now the trial has been expanded to a second group of five patients and the first of those has been implanted with a double dose.

LCT medical director Professor Bob Elliott said the first group of Russians had shown reductions in daily insulin requirements ranging from 23 percent toas much as 100 percent, while maintaining good control of blood glucose levels in four out of five patients.

In patients who had the longest follow-up period, there had been reductions in insulin requirements of 24 percent and 54 percent respectively.

The implanted pig tissues were known to have continued producing porcine insulin up to 11 months after the first implant.

An important measurement of blood glucose, the mean glycated hemoglobin (HbA1c) level, fell from 8.5 percent pre-implant to 6.8 percent, and the lowest patient response was a 10 percent reduction in daily insulin requirement.

Prof Elliot said swings in blood glucose levels and diabetes control had improved dramatically but with a smaller insulin dose and the lowest dose of pig cells.

"Higher doses of DiabeCell will support greater and longer term reductions in the insulin needs of patients."

Prof Elliot originally made similar transplants in 1996 and 1997, but the clinical trials were blocked by regulators because of fears that the animal transplants could transfer pig viruses into humans.

LCT has said that it does not believe wide public consultation was necessary for injecting porcine islet cells into type-1 diabetics.

But a Wellington thinktank, the Sustainability Council, has urged the minister to consult the public on the "community risk" in the event that transplanted pig tissues trigger an infectious disease in humans.

It has also questioned how transplant recipients can be stopped from donating blood or organs to other humans.

5m Editor