KEY POINTS:
Experimental pig cell transplants into humans with type-1 diabetes are to resume in New Zealand after an 11-year break - raising hopes of better treatment for people with the incurable disease.
"Scientific approval has been given, which is a major breakthrough," the Auckland pioneer of the treatment, Professor
Bob Elliott, told the Herald yesterday.
Nicola Zimmerman, a 25-year-old architect and former Elliott patient with diabetes, was ecstatic that the treatment was a step closer to possibly being an option for her.
"Just the thought of not having to inject insulin is one of the most exciting things," she said. "It's quite an emotional thought."
About 11,000 New Zealanders have type-1 diabetes, which is different from obesity-linked type-2 diabetes.
Type-1 diabetes usually starts in childhood, and leaves people unable to produce much or any insulin, a substance the body uses to process glucose. They need regular injections of synthetic insulin.
Professor Elliott's company, Living Cell Technologies, takes clusters of insulin-producing cells from the pancreases of killed newborn piglets and coats them with a seaweed-based gel so they can be inserted into the patient's abdomen. Each patient receives billions of the pig cells.
No immune-suppression drugs are used. The gel protects the cells from the immune system, but admits substances such as glucose, which stimulate insulin production.
Human trials of an earlier version of the technology were halted in 1996 because of fears the transplants could lead to pig retroviruses infecting the human population.
But Living Cell says there is no evidence of humans or other animals that have had the transplants being infected.
Professor Elliott said that if all went well with the clinical trials of the company's Diabecell product, it could be available as a treatment for patients in two years.
He said the Health Ministry's Medsafe unit had authorised the new trial after extensive international consultation by a Health Research Council committee to canvass ethical and cultural matters, safety, public health and scientific data.
"They have come away with the opinion that it's a safe procedure and there is no hindrance to us going ahead," he said.
Approval was still needed from a ministry ethics committee in Auckland, but Professor Elliott expects this to be straightforward and take about two months.
He expected the trial at Middlemore Hospital could start in the second half of the year. It would involve eight adults and would check for safety and preliminary efficacy.
In animals with diabetes, Living Cell's pig-cell transplants have produced a significant reduction in insulin requirements and freedom from insulin dependence in some cases, with no adverse effects.
The ministry had little to say yesterday on the trial, except to note that it still needed approval from the regional ethics committee.
A participant in the 1996 trial, Aucklander Michael Helyer, was tested again last year. Pig cells were still producing some insulin in him, and he said he was still deriving some benefit. For more than a year after his transplant, the cells enabled him to reduce his injected insulin by a third, and he had better control of his blood-glucose levels.
Nicola Zimmerman was 9 1/2 when her diabetes was diagnosed, and she has followed developments of the experimental treatment closely.
She finger-prick-tests her blood-glucose level, and injects insulin five times a day. She maintains fairly good control of her levels, but has had a few low-sugar scares.
"I usually feel myself getting a bit shaky and can get a glass of orange juice [for glucose]."
For Living Cell, it is the second pig-cell transplant regulatory approval within three months. A trial on six adults, approved in January, is about to begin in Russia.
Other companies have tried different types of transplants, including from rabbits, for diabetes.
But Living Cell chief executive Paul Tan said his company preferred pigs because pig insulin was very similar to human insulin and because only six piglets were needed for each patient, against 80 rabbits.
The company's pigs, kept in Auckland and Invercargill, are descended from animals left on the subantarctic Auckland Islands 200 years ago.
Dr Tan said they were free of viruses found in other pigs and of viruses that were important to exclude from transplants to humans.
Diabetes
There are two main types of the disease. Both have long-term risks from high blood-glucose levels, including heart disease, blindness and kidney failure.
TYPE 1
* Affects about 11,000 New Zealanders.
* Cause unknown, but possibly a virus in those genetically predisposed.
* The immune system kills most of the cells that produce insulin, a substance the body uses to process glucose.
* Patients must regularly test blood-glucose levels and inject synthetic insulin.
* Lack of insulin or low glucose levels can cause coma and death.
TYPE 2
* About 110,000 people diagnosed and possibly as many again undiagnosed.
* Tends to run in families.
* Linked to obesity.
* The body does not produce enough insulin and stops using it properly.
* Insulin injections may be needed. Other medicines often used.
* High blood-glucose levels can cause seizures.
