2010: a Sydney Project

Professor Bernie Tuch is not a man given to hyperbole, so if he thinks it a not unreasonable chance that human embryonic stem cells, differentiated into insulin-producing cells, will be in clinical trials to treat type 1 diabetes in the next four or five years, few are going to argue.

Tuch has directed the Diabetes Transplant Unit, based at Sydney's Prince of Wales Hospital, since 1991, and since then has been working steadily on finding a cell-based treatment for diabetes using a number of methods.

The Sydney Project is part of a global initiative to devise a cell therapy for diabetes in the shortest possible timeframe. The name is coined after the Chicago Project, an initiative led by Professor Jose Oberholzer, who runs the islet transplantation facility at the University of Illinois Medical Centre in Chicago.

Oberholzer is running trials of islet transplantation into the liver, one of many such trials around the world dedicated to finding a way to replace the insulin-producing cells destroyed in diabetes. More recently he has decided to extend these studies which use anti-rejection therapies into the more novel approach of placing the islets in microcapsules to avoid the need for such therapies. Clinical trials are pending.

For Tuch, who collaborates with Oberholzer, this is not a new project. In February 2006, he commenced a similar trial in Sydney, where resources are much fewer than those available in Chicago. Termed the seaweed diabetes trial, islets from donor pancreases were encapsulated in an alginate coating to prevent rejection and injected into the patient's peritoneal cavity, performed on an outpatient basis.

This phase 1 safety trial, which has been running since February 2006, has achieved modest results. Tuch's team presented data at an endocrinology conference in New Zealand late last year showing that the team had complete six transplants in three patients - one patient receiving four transplants - with an average of 172,000 islet equivalents per transplant.

"We showed some early function in those but it didn't have clinical benefit beyond the first week," Tuch says. "So what we are doing now is modifying the technology to enhance the function of the cells."

Tuch and his team at the DTU have been perfecting the technique of microencapsulation with sodium alginate, solidified in barium chloride, for the last eight years or so. It has applications in drug delivery and cell culture as well as transplantation studies, so the DTU has now decided to offer microencapsulation as a service to other research groups. The service is managed by Dr Jayne Foster, who is also involved in some of the unit's xenotransplantation work.

"The platform technology of microencapsulation is one we have developed with the assistance of a group in Germany, Karin Ulrichs' group in Wurzburg," Tuch says.

"Karin came out and taught us the procedure and we've worked with her in relation to it. So what we do is apply it specifically to encapsulating human islets as part of our seaweed diabetes trial, and we are encapsulating insulin-producing pig cells for use in mice and also encapsulating embryonic stem cells as part of a culture system."

Tuch says his group's expertise with microencapsulation, and speaking about it at conferences, led several groups to approach him to see if they could use the platform technology for their own purposes, mainly for growing cells in a 3D culture system and also for encapsulating structures so they are isolated when they are being transplanted. It is also aimed at drug delivery research.

---PB--- City projects

Microencapsulation of insulin-producing cells is a platform technology Tuch believes will overcome many of the drawbacks of other islet transplantation studies, particular the obvious drawback of immune rejection.

And while the current trial uses islets from cadavers, it is obvious the technology can be used with a number of different sources of insulin-producing cells. The DTU is investigating a number of these in addition to the donor pancreases, including human embryonic stem cells; stem cells derived from cord blood, the nose and the fetal pancreas; animal pancreas, particular pig; and genetically modified cell lines.

The Sydney Project is aiming for the human embryonic stem cell approach. "The thrust of what we are doing now is what we call the Sydney Project, which says that by 2012 we will be in clinical trials with human embryonic stem cells which will be differentiating into insulin-producing cells," Tuch says.

Research groups around the world now have their own 'city projects' and have agreed to share data. Examination of the data show the DTU where it is compared to others and what is possible considered the resources it has.

"The Sydney Project is a dream but it is based upon reality in terms of where we are and where our 'competitors' are," Tuch says. "The rate of progress that has been made, and our peers' perception of our data, tells us it isn't pie in the sky."

The project has a number of issues to overcome in that time, the first being to convert embryonic stem cells into insulin producing cells, which Tuch says that Novocell in California has achieved. Then there are the issues of safety - avoiding tumours, preventing rejection and the regulatory issues that everyone the world over has to deal with in one way or another.

"This is why I think five years is not unreasonable," he says. "No human embryonic stem cell is used yet in a human trial, but Geron is about to start one as a therapy for spinal cord lesions. They've put in their application for regulatory approval and it is not hard to see how the dominoes are likely to fall in the next five years."

The DTU has a co-operative agreement with IVF Australia to produce human embryonic stem cell lines from spare fertilised eggs and has produced two such lines: Endeavour 1 and Endeavour 2, the first of which is being used and will soon be distributed by the UK's Stem Cell Bank. The team has been able to convert hESCs into pancreatic progenitors using a two-stage, eight-day culture protocol and further work is being done to develop the cells into surrogate insulin-producing ones.

It is also investigating reprogramming cells using somatic cell nuclear transfer to create patient- and disease-specific lines. The lack of availability of unfertilised eggs has led it to investigate a number of novel sources, including the use of eggs from women who are having their ovaries removed to reduce the risk of them developing ovarian cancer.

"That is in the process of gaining approval here in Australia so it is early days yet. Getting normal eggs from an IVF clinic is a very conjectural one ... you can get around that problem using animal eggs but that is not allowed in Australia yet."

---PB--- Alternatives to hESCs

While hESCs is the focus of the Sydney project, Tuch says insulin producing cells should be obtained by any source that is available. That includes the fetal pancreas, an area his group has published on recently.

(Tuch is very keen to ensure that journalists get it right when spelling fetal - the derivation is from the Latin fetare, meaning to bring forth young, and the commonly used 'o' after the 'f' is a mistake. And if The Lancet picked up the error more than 50 years ago, it's probably about time Australian Life Scientist did the same.)

"We have a paper just out in Diabetes which talks about immunogenicity of immature pancreas," he says. "If you take pancreas from therapeutic termination of pregnancy early enough, in the first trimester, and transplant that into a humanised mouse, it won't be rejected. But if you take a later one - in the second trimester - it will.

"My thoughts are that if the immature pancreas doesn't get rejected but the mature pancreas does, could you differentiate the embryonic stem cell, the pancreatic progenitor, up to a certain level and then transplant it without the need for anti-rejection drugs?"

Other areas of exploration are using cord blood and also olfactory ensheathing cells, a project the team is working on with Professor Alan Mackay-Sim from the Eskitits Institute at Griffith University. While this work has not yet been published and he hesitates to say too much, the techniques the team used to produce definitive endoderm and pancreas progenitors in hESCs does not work in cord blood stem cells or olfactory cells.

"There are two interpretations - one is that the technique for one is not the same as for the other, and the other interpretation is that perhaps the pluripotent nature of the embryonic stem cell gives them an advantage over the multipotent nature of cord or olfactory. Which of those it is, I don't know."

And there is the work he has long wanted to pursue but has been hobbled by government - xenotransplantation, upon which there is a moratorium in Australia. He knows the reasons given for the moratorium but still doesn't understand it, but is nonetheless encouraged by recent research addressing one of xeno's problems - the transfer of porcine endogenous retroviruses.

He has not seen the data from Living Cell Technologies, the Auckland company that is trialling transplants of pig islets from its isolated herd, but he imagines there will be enough evidence from that work to perhaps help in overcoming the moratorium in Australia, due to lapse next year.

In the meantime, he will continue to do his research, see his patients and continue his work talking to community groups about science, which he takes very seriously. And he wouldn't mind some assistance from venture capitalists, if there are any out there not currently obsessed with resource stocks. "The basis of all solid research," he says, "is not just the ideas but finding the finances to support them."

---PB--- Induced pluripotent stem cells

Anyone working in stem cell research anywhere in the world must have been intrigued by the recent headlines about induced pluripotent stem (iPS) cells, carried out by Shinya Yamanaka's group at Kyoto University and also by James Thomson's team at the University of Wisconsin-Madison. Australia's Andrew French has also been in the news with his work at Stemagen in California on SCNT.

"It's encouraging," Tuch says about French's work. "The way I read it is that he's trying to make patient-specific stem cell lines and he has shown that with normal unfertilised eggs he can produce an embryo through somatic cell nuclear transfer. Whether he can make a stem cell line out of that remains to be seen."

On the work of Yamanaka and Thomson, he believes it is a good, complementary approach. "There are some dangers associated with it but the strengths are that [iPS cells] are attractive in terms of concept. The two groups are using a slightly different approach but they are basically genetically modifying somatic cells.

"If you talk to experts in gene therapy - which I am - they will ask how stably transfected are these cells. Is this long term or only short term? There are the obvious safety issues as well. But it is encouraging that this sort of research is occurring. "Will it overcome the need for embryonic stem cell lines? Time will tell."