Encapsulated islets in humans - Australia

[Ellen]

With cautious optimism, I smiled this morning reading this article. Wishing Dr. Tuch godspeed with his research. I hope this will work and if it does, I hope we'll be able to try it with porcine islets, because there are not enough cadaver islets available.


Diabetics get kelp to dump the needle
By Ben Cubby
February 21, 2006


A NEW treatment for type 1 diabetes using a brown seaweed extract may ultimately mean an end to daily injections for many of the 130,000 Australians who live with the disease.

During the first clinical trial yesterday, doctors at Sydney's Prince of Wales Hospital injected Janice Stewart with insulin-producing cells encased in microscopic, perforated capsules of seaweed extract.

If the trial goes as expected, many patients might have to take only one or two injections in a lifetime, instead of several a day.

The insulin-producing cells sit in a patient's abdomen, releasing insulin but guarded from the body's immune system by the seaweed shell. Tiny holes in the seaweed allow insulin to enter the patient's bloodstream, and let in nutrients to feed the cells, but are small enough to keep out antibodies.

The catch is that the insulin- producing cells must be gathered from the pancreas of a non-diabetic organ donor who died very recently.

They must then be placed inside the seaweed microcapsules, which are only about three-thousandths of a millimetre in diameter, a process likened to "blowing in soap bubbles" by University of NSW researcher Professor Bernie Tuch, who is leading the hospital research team.

"Even if we are able to get numbers of people like Janice off insulin, the supply problem is enormous," Professor Tuch said.

"Last year, for example, there were 204 people who died and donated their organs. There are 130,000 people like Janice in this country."

A shortage of donors means the new treatment, if successful, would be used to supplement existing treatments, which require regular injections of anti- rejection drugs.

Ms Stewart, 51, said she felt "fantastic" after being injected with the seaweed microcapsules yesterday. She developed the disease 40 years ago, and has been taking four insulin injections a day.

"If it works I think it's the best thing that's happened for diabetes since the discovery of insulin," said Ms Stewart, who is a nurse at the hospital and is one of six diabetics in the trial.

"At the minimum it will mean less insulin (injections) for me. Hopefully for the kids of today who are developing diabetes at the age I did they may not have a whole lifetime of it."

The NSW chief executive of Diabetes Australia, Liz Peers, said the organisation supported the trials and looked forward to the results.

• http://www.theage.com.au/news/national/diabetics-get-kelp-to

[Ellen]

Seaweed bubbles may fight diabetes

Judy Skatssoon
ABC Science Online

Tuesday, 21 February 2006


Researchers have put insulin producing cells like this into tiny capsules as a treatment for type 1 diabetes (Image: NIH)
Encapsulating insulin producing cells in tiny seaweed bubbles and injecting them into people with type 1 diabetes could one day remove the need for daily insulin injections, an Australian researcher says.

Professor Bernie Tuch of the University of New South Wales launched a trial of the technology this week, using capsules made from the seaweed derivative alginate and measuring just 300 micrometres across.

Tuch says if the trial works, it will mean that insulin producing cells, or islets, can be transplanted, effectively reversing type 1 diabetes, without the need for immunosuppressive drugs.

This is because the capsules protect the transplanted cells from being sought out and destroyed by the body's immune system.

The capsules also contain tiny holes that let the insulin flow out while allowing oxygen and nutrients in.

"The concept of the seaweed is that it forms a coating around the islets ... with holes that are small enough to prevent immune cells entering," Tuch says.

The trial, involving a 51-year woman who was diagnosed with type 1 diabetes 40 years ago, is the first of its kind in Australia.

Tuch's team at the Diabetes Transplant Unit at Sydney's Prince of Wales Hospital has previously tested the method in animals.

An Italian group began a similar human trial two years ago but is using capsules made from a different material.

About 75,000 capsules
During Monday's half-hour procedure the woman was injected with 75,000 capsules containing a total of around 200,000 islet cells.

The islets had been isolated from a cadaver and put into the capsules in a procedure Tuch compares to blowing soap bubbles.

"There's the alginate, there's your cells and there's air," he says.

"You blow the air and the alginate and the cells together and it's like blowing soap bubbles; they come out with the cells inside the capsules."

The capsules were injected into the patient's abdomen where it's hoped they will start producing insulin within 24 hours, allowing her to slowly begin reducing her insulin injections.

Microcapsules containing insulin producing cells (Image: DTU)
Tuch says one injection could potentially last a lifetime although it's not yet known whether the current patient will need extra injections.

What could go wrong?
Immunologist Dr Bronwyn O'Brien, who is working with a team from the University of Technology Sydney to genetically engineer liver cells so they produce insulin, says Tuch's method is promising but may have complications.

"In practice one of the big problems is that ... often islets that are in the centre of the capsule become hypoxic, they're not getting oxygen, and they die," she says.

"The implications would be the cells would break up into possibly small enough pieces that could leave the capsule."

There's also a chance that immune cells could grow around the outside of the capsules, blocking the flow of insulin, she says.

And while the pores in the capsules are big enough to keep T cells and antibodies out, there's still a chance that cytokines, the so-called messengers of the immune system, will slip through and produce an inflammatory response.

Tuch acknowledges this risk and says the patient received anti-inflammatory drugs as a precaution.

"We don't anticipate there is going to be a major inflammatory response but if they do get in then the islets may be destroyed," he says.

Not just for diabetes
The concept of microencapsulation as a means of avoiding rejection drugs could apply to any transplant involving cells, Tuch says, and in particular stem cell therapies.

"The concept of using capsules is certainly something that is reaching its clinical testing and time will tell what it has to offer," he says.